SFII Exam

Liquefactive Necrosis: Liver

The liver shows a small abscess here filled with many neutrophils This abscess is an example of localized liquefactive necrosis.

Amyloidosis

"A group of disorders associated with a number of inherited and inflammatory disorders in which extracellular deposits of fibrillar proteins are responsible for tissue damage and functional compromise." - Pathogenesis likely involves abnormal protein folding. - Often involves immune components. - Spectrum of clinical disease; a group of diseases having in common deposition of a similar appearing substance/protein.

Dysplasia

"Disordered growth" Cells look 'malignant', but remain confined within the basement membrane. Some epithelial tissues undergo this process as a pre-neoplastic change: stepwise progression of accumulating genetic alterations. - Loss of uniformity of individual cells (nuclear enlargement, membrane irregularities - Loss of architectural orientation (polarity) - Display cytologic abnormality and pleomorphism Dysplasia can be qualified: - mild - moderated - severe Severe dysplasia for epithelial tissues is referred to as 'carcinoma in-situ'. Often found adjacent to invasive carcinoma. Not all forms of dysplasia progress to invasive carcinoma, but there is usually some potential to do so

Hemodynamics: Microscopic Thrombosis

"Lines of Zahn" Alternating pale pink bands of platelets with fibrin and red bands of RBC's forming a true thrombus

Metastasis

"Tumor implants discontinuous with primary tumor". Metastases are a distinguishing feature of malignant neoplasms Approximately 30% of newly diagnosed patients with solid tumors (not blood related cancers such as leukemia) will present with metastases. Metastatic disease strongly reduces the possibility of cure. Pathways of Spread 1. Direct extension and seeding 2. Lymphatic - Tumor invades lymphatic vessels to eventually lodge in regional lymph nodes. (Follows natural routes of lymphatic drainage). 3. Hematogenous - Tumor invades blood vessels - Liver and lungs frequently involved secondarily with hematogenous dissemination

Beta-blocker with partial (low) agonist activity

("intrinsic sympathomimetic activity = ISA") at beta receptors 1. Pindolol - prototype - β1 and β2 weak partial agonist - nonselective beta-blocker with ISA at beta-1, beta-2 receptors - Because it has ISA at beta-receptors in the heart it doesn't slow resting heart rate as much as other beta-blockers, but still blocks increase in HR and CO produced by SNS stimulation - Therefore, it is less likely to cause severe bradycardia in hypertensive patients with low resting HR (a long-distance runner or cyclist).

Cell Injury

- Cells can adapt to stress within limits. - Too much stress can lead to injury and death. - Thought to be a reversible stage which some cells pass - Various noxious stimuli can induce changes in the cell - If a cell cannot adapt to a particular noxious stimulus, it may undergo cell death - There are specific findings, both at the organellular level and at the microscopic level that define reversible and irreversible injury/necrosis. Results from functional and biochemical abnormalities of essential cellular components. Type of injury depends on: - type of cell - degree to which it can adapt Cellular response depends on: - type of injury - duration - intensity

Edema: Sodium Retention

- Water follows sodium - mechanisms involved are complex physiologically - higher blood volume associated with increased hydrostatic pressure and diminished colloidal osmotic/oncotic pressure

Liquefactive necrosis

- complete enzymatic digestion of the cell - result is a liquefied, soft and gelatinous defect in tissue - typical of hypoxic/ischemic injury in brain - typically of various bacterial and fungal infections

Agonists (Full Agonists)

- drugs that cause activation of receptors - drugs that occupy receptors and bring about a full or maximal response - maximal response is usually defined as that produced by most powerful agonists, or that produced by a drug associated classically with the response Two Hypotheses: 1. Binding - Conformational Change - Activation - D + R <--> DR <--> R* --> Response 2. Conformational Change - Activation - Binding (stabilization) - Effects occur even when no agonist is present --> Constitutive Activity - agonist stabilizes active form of receptor (binds with greater affinity to active conformation of receptor than inactive conformation) Resting ratio of R/R* is high (99/1) - majority of receptor is in resting/inactive conformation Agonist/Full Agonist 1. D has high affinity for R* (Kd = 1nM) and low affinity for R (Kd = 1mM) - D pulls receptors into DR*

Coagulative necrosis

- most common type - often caused by hypoxic injury - Characterized by preservation of basic outline of the 'coagulated' cell for a few days - increased acidosis in the cell, which denatures proteins, including enzymes which would otherwise digest the cell - inflammatory cells that come to the site will eat the dead cells - Coagulation necrosis occurs with hypoxic injury in all tissues except the brain that undergoes liquefactive necrosis.

Fat necrosis

- refers to enzymatic destruction of fat that can occur in the abdomen with pancreatic injury OR - refers to peripheral fat usually damaged by some sort of trauma

Paraneoplastic Syndromes

1. Endocrinopathies - Cushing's Syndrome - Paraneoplastic Hypercalcemia - Sydrome of Innappropriate ADH Secretion (SIADH) 2. Immunologically-Mediated 3. Hyper coagulability 3. Cachexia

Inverse Agonism: New Concept

1. Almost all physiological systems have low constitutive activity (R/R* is high) - cannot detect inverse agonism - inverse agonists and neutral antagonists look the same - resting ratio R/R* of 99/1 is the normal condition for most physiological systems 2. Transfected cells and transgenic mice and few physiological systems have constitutive activity (R/R* is not high) - can detect inverse agonism

Consequences of Drug Metabolism

1. Active drug --> inactive metabolite - Example: Phenobarbital --> p-hydroxyphenobarbital 2. Active drug --> active metabolite - Metabolite with same or new activity - Example: Fluoxetine --> Norfluoxetine (methyl group removed) - Example: Procainamide --> N-acetylprocainamide (NAPA) 3. Inactive drug (prodrug) --> active metabolite - Example: Enalapril --> Enalaprilat 4. Active drug --> toxic metabolite Example: Meperidine --> normeperidine - If normeperidine accumulates (in a patient with renal impairment, for example), CNS toxicity including seizures may occur

Drugs that Increase Release of Catecholamine Neurotransmitters (NE and DA)

1. Amphetamines and related drugs e.g. methylphenidate (Ritalin) - Release NE and prolong NE actions in SNS - In CNS these drugs do same for NE, DA and serotonin Amphetamines' Mechanism: 1. Inhibits re-uptake pumps: Competitively blocks reuptake pumps so transmitters have more prolonged effects in the synapse 2. Amphetamine enters axons where it inhibits VMAT-2 and MAO - Catecholamine release is increased by reversing re-uptake pump - Results in increased concentration of neurotransmitter free in nerve ending cytoplasm, which reverses concentration gradient - re-uptake pump transports neurotransmitter out of axon terminal into the synapse = release. - But note, this increased release is not by a normal physiological process Amphetamines have strong reinforcing properties (primarily via DA) - Thus they have high abuse potential - Tolerance develops - Prolonged use of escalating doses can lead to depressive episodes and can exacerbate or even lead to acute psychotic-like episodes. Drug Uses: - ADHD, narcolepsy, general stimulant. - used for their CNS actions - primarily to treat Attention Deficit Hyperactivity Disorders and narcolepsy - Why do they work for ADHD? Probably because they increase focus (attention). 2. Ephedrine - Enters nerve NE terminal and can displace NE from cytoplasm increasing NE release - also weak agonist at adrenergic receptors (alpha-1, beta-1 & beta-2 receptors) --> relaxes bronchial smooth muscle, stimulates heart, raises BP Drug Use: Ephedrine and similar drugs often found in OTC cold drugs, weight loss preps - was sold OTC as a nasal decongestant because of its vasoconstrictive actions and as a bronchodilator - also a mild CNS stimulant and appetite suppressant. - Current controversy over uses because of variability of doses in OTC products - especially herbal preps, herbals not regulated by FDA Tolerance develops. Warning: Restrictions on sales of ephedrine because it can be used as starting material for illegal synthesis of methamphetamine Note: both amphetamines and ephedrine lack a ring hydroxyl group, so they are not metabolized by COMT Pseudoepedrine has largely replaced ephedrine in OTC cold preps. It too produces tolerance. . 3. Tyramine - Enters sympathetic nerve axons through reuptake pump and increases release of NE - Can displace NE from axon similar to ephedrine Not used clinically Product of normal gut bacteria and is also found in high concentrations in certain fermented foods (yogurt, wine, beer, aged cheese, etc.) - Tyramine is normally rapidly metabolized by monoamine oxidase (MAO) enzymes in gut and liver, so normally it doesn't reach the general circulation in appreciable concentration. But what happens if MAO is inhibited? - Basis for an important interaction between these foods and drugs that inhibit MAO enzyme (MAO inhibitors) - so-called "cheese reaction", which can be life-threatening All of these drugs produce release of catecholamines that is non-physiological Ca2+-independent pathway What about a drug that blocks presynaptic a2a and a2c receptors (normally inhibitory)

Classes of Pathogen

1. Bacteria 2. Fungi 3. Viruses 4. Parasites Sentinel cells of the immune system (mainly DCs) are able to identify each class of pathogen and determine whether its location is extracellular or intracellular - accomplished by receptors on cell membrane, in phagosomes and in the cytosol of sentinel cells - receptors are termed pattern recognition receptors (PRRs) - PRRs recognize conserved structural motifs on different classes of pathogen - motifs are called microbe-associated molecular patterns (MAMPs) NOTE: MAMPs are components of ALL bacteria, ALL fungi, ALL viruses and ALL parasites - Each class of pathogen has its own set of MAMPs - For example, bacteria have different MAMPs to fungi, viruses and parasites, etc.

Beta-Adrenergic Receptor Antagonists: Pharmacological Effects

1. Blockade of beta-1 receptors in the heart leads to: - decrease contractility (decrease SV) - decrease HR - resulting in decreased CO (HR x SV) 2. Blockade of beta-1 receptors in the kidney: - causes a decrease in renin release in response to SNS stimulation - Would lead to less Na+ and water retention causing a decreases in blood volume --> decrease in BP 3. Blockade of beta-2 receptors in airway smooth muscle: - will prevent EPI-mediated bronchodilation (very important in asthmatics and other patients with airway disease) - So, all beta-blockers, even those that are selective beta-1 blockers, are usually contraindicated in asthmatics - Remember: selectivity is almost always relative and dose dependent, and selectivity diminishes as the dose increases 4. Blockade of beta-2 receptors in the liver: - will partially block breakdown of glycogen that occurs in response to EPI released during hypoglycemia - problem in insulin-dependent diabetic patients, who may depend on this liver response to recover from hypoglycemic episodes - Beta-1 selective blockers are preferable in these patients Graph: Effect in an anesthetized dog of the injection of epinephrine before and after propranolol - In the presence of a B-receptor-blocking agent, epinephrine no longer augments the force of contraction (SV) nor increases cardiac rate (HR) - Blood pressure is still elevated by epinephrine because vasoconstriction is not blocked (a1 mediated)

Direct Adrenergic Receptor Agonists: Epinephrine

1. Epinephrine Stimulates all 10 alpha and beta adrenergic receptors Low dose: primarily beta-2 effects (vasodilation) Higher dose: beta-1 (heart) and alpha effects (vasoconstriction)

Precaution with all B-adrenergic Receptors

1. Cardiac depression - used cautiously in patients with inadequate cardiac function, but still used. 2. Bronchoconstriction in patients with airway disease, asthma - even b-1 selective blockers can be problematic, so usually β-blockers should not be used in asthma - an exception could be immediately after an MI to prevent potentially fatal cardiac arrhythmias 3. Beta-blockers will usually decrease glycogenolysis in liver - Will mask important signs of hypoglycemia - These are potentially important problems for diabetics, especially, insulin-dependent diabetics.

Therapeutic Uses of Catecholamines and Related Agonists

1. Cardiogenic shock - Dopamine and Dobutamine can increase CO with less increase in TPR compared to Epi (at high doses) - Why is that important? DA increases perfusion of renal and mesentery vessels 2. Septic shock - NE is usually preferred because it reliably raises BP, which counters the very marked fall in BP in septic shock (mortality rate 40% or higher) - Minutes count! 3. Heart Failure (Acute episodes) - B1 effects - Dobutamine increases CO without excessive increase in TPR - there is less workload on heart - used via infusion in HF and sometimes in septic shock 4. Anaphylactic shock - intramuscular EPI is used to cause vasoconstriction via alpha-adrenergic effects (a1 & a2) (counteract hypotension) - decrease mucous membrane congestion via alpha effects - produce bronchodilation (b2-adrenergic) - increase cardiac contractility via b1-adrenergic effects 5. Cardiac arrest or complete heart block - B1 effects - EPI and Isoproterenol - (b-1 effects on SA and AV node). Why not NE? 6. In combination with local anesthetics - EPI by vasoconstriction via alpha in the region where the anesthetic is injected, decreases its diffusion and prolongs the duration of the nerve block - Toxicity is decreased since the amount of local anesthetic absorbed systemically is reduced. 7. Asthma and bronchospasm - EPI and ISO delivered by inhalation produce bronchodilation by stimulating b-2 receptors in bronchial smooth muscle - selective b-2 receptor agonists are preferred because they have fewer cardiac effects

Selective α2-adrenergic receptor agonists

1. Clonidine Initially vasoconstrictor when given iv But lowers BP when used clinically (orally) - when injected i.v.: stimulates postsynaptic alpha-2B receptors in peripheral vasculature causing vasoconstriction - when injected i.v.: also decreases NE release via a presynaptic (autoreceptor a2A) mechanism: auto inhibitory - After oral administration, decreases peripheral sympathetic outflow by stimulating postsynaptic alpha-2A receptors in CNS cardiovascular centers in the medulla (vasomotor centers) --> decreases activity of SNS - Used as an antihypertensive drug Sudden withdrawal from clonidine has been reported to result in hypertensive episode. Example of receptor adaptation? - withdrawal of SNS inhibition - a1 receptors of bv are more sensitive to NE? α-methyldopa - alpha-methyl-DOPA - another antihypertensive drug - probably lowers blood pressure in a similar manner after conversion to α-methyl-NE in brain (decrease SNS outflow by stimulating a-2A inhibitory receptors - α-methyldopa is used mainly in hypertension during pregnancy α2 agonists or partial agonists have also been tried in: - Tourette's - Withdrawal from opiates - ADHD - Data so far is inconclusive but still emerging 2. Brimonidine - alpha-2 agonist - used topically in eye to treat glaucoma - It decreases intraocular pressure by decreasing aqueous humor production Figure!! - Evidence that α2A-adrenergic receptor mediated feedback regulation of NE release is physiologically active and relevant to cardiac function. - The heart and NE content of coronary venous blood was measured during periods of stimulation of the SNS cardiac accelerator nerve before and after clonidine or the alpha-adrenergic receptor antagonist phentolamine (all alpha receptors!!! --> blocks NE negative feedback inhibition at presynaptic nerve terminals)

Drugs that Decrease Release of NE (and other NTs)

1. Clonidine - All SNS axons have presynaptic alpha-2 receptors (inhibitory) - Clonidine stimulates presynaptic alpha-2A and alpha 2C adrenergic receptors that hyperpolarize NE axon terminal --> decreased firing rate of neurons --> results in decreased release of NE - These receptors are also on neurons in CNS, where they may decrease firing rate of neurons NOTE: Clonidine also stimulates postsynaptic alpha-2B receptors on vascular SM leading to vasoconstriction - Yet, clonidine is an antihypertensive drug - How does it work? It decreases SNS signals from the CNS --> decreases sympathetic outflow from CNS (a2A inhibitory receptors) Drug Use - Hypertension: less used now - Tourette's syndrome in children and has been used to treat withdrawal from some drugs of abuse, including opiates) 2. Botulinum Toxin - toxin blocks docking and fusion of vesicles containing ACh - Blocks coupling of two vesicular proteins, VAMP & SNAP - leading to paralysis of muscles Drug Use: 1. spastic disorders to relax muscles 2. paralysis of small muscles of face by Botox: fewer wrinkles (and insurance-free billing) - In higher amounts, as occurs from contaminated foods, it can paralyze breathing and is often fatal (it is one of the most potent toxins known) c. Tetanus toxin - similar mechanism but in the CNS where it blocks GABA neurotransmission - decrease release of GABA in the CNS - Consequences: Tetanic (prolonged) contraction of muscles and possible Seizures - GABA is inhibitory, if blocked loss of normal inhibitory --> titanic contractions

Types of Shock

1. Distributive - septic or non-septic 2. Cardiogenic 3. Hypovolemic 4. Obstructive

Drug Metabolism

1. Drug metabolism: an enzyme-catalyzed change in chemical structure (chemical transformation) - Usually increases polarity to promote renal and biliary excretion - More than 1 pathway may be involved in metabolism of a given drug 2. First Pass Metabolism (First Pass Effect) - Metabolism in intestinal mucosa or liver before reaching systemic circulation for some orally administered drugs - if substantially metabolized referred to as first pass effect - ex: propranolol, lidocaine, morphine 3. Enterohepatic Recycling - continuing cycle of biliary secretion and intestinal reabsorption - results in long/prolonged elimination half-life - Can result in a 2nd peak in the plasma-concentration time course - ex: indomethacin, cyclosporine

Four Main Aspects of Disease Process

1. Etiology (cause) - Genetic or acquired - most disease is multifactorial 2. Pathogenesis (mechanism) - Sequence of cellular, biochemical or molecular events that follow exposure of a cell to injurious stimuli (stressor) 3. Morphology - Structural alterations in cells or tissues characteristic of a disease process - structural changes of organs and cells 4. Clinical manifestations - functional changes

Pathologic Apoptosis Etiology

1. Exogenous noxious stimuli: - include many of same agents that can induce necrosis (drugs, radiation). 2. Viruses: Prototype is viral hepatitis. 3. Tumors: seen in both regressive and actively growing tumors

Four Pathways of Cellular Accumulations

1. Inadequate removal of a normal substance secondary to defects in mechanisms of packaging and transport 2. Accumulation of an abnormal endogenous substance as a result of genetic or acquired defects in its folding, packaging, transport, or secretion 3. Failure to degrade a metabolite due to inherited enzyme deficiencies 4. Deposition and accumulation of an abnormal exogenous substance when cell has neither the enzymatic machinery to degrade the substance nor the ability to transport it to other sites

Clinical Aspects of Neoplasia

1. Local invasion - Tumors can grow into adjacent organs, vessels, etc - cause obstruction, bleeding, organ failure 2. Distant metastases - Tumors can spread via lymphatic channels or hematogenouly or through tumor seeding - affect distant organs causing organ failure e.g. liver failure - brain (hard to treat, chemo and BBB) - bone (lytic or blastic, more common to axial skeleton, prostate cancer, breast cancer, risk of spinal cord compression, bisphosphonates to reduce new metastases ) 3. Infections - One of leading complications in patients with cancer and who are treated with immunosuppressive therapies - Bacterial, viral, fungal infections can lead to multi-organ failure and sepsis 4. Bleeding / Thrombosis - Disseminated intravascular coagulation (DIC): Systemic activation of coagulation consumes factors and platelets produce bleeding, vascular occlusion and tissue hypoxia - Tumors produce procoagulant factors, can lead to the vein thrombosis (DVT) or pulmonary embolism

Beta-1 Selective Blockers

1. Metoprolol - prototype - short t1/2 ~ 4 h or extended release - These drugs may provide greater exercise tolerance than the nonselective agents - During stress or exercise, or in peripheral vascular disease, beta-2 receptors in skeletal muscle vasculature can still mediate vasodilation in response to higher circulating EPI levels (don't want to block those Beta-2) - In diabetics, glycogenolysis is less impeded, so there is better recovery from hypoglycemic episodes (beta2 mediated) 2. Atenolol - t1/2 ~ 7 h; not used in renal insufficiency Advantages of Selective β1-blockers 1. β1 selective blockers usually allow better exercise tolerance - Better blood flow to muscles (why? β-2 receptors not blocked) - less block of muscle K+ uptake, which is mediated by β-2 receptors. 2. β1 blockers produce less blockade of liver glyogenolysis, which is mediated by β2 receptors. - Also less masking of hypoglycemic symptoms- important in diabetic patient. Partial agonists (ISA) Better exercise tolerance especially for patient with low heart rate

Drugs that Effect Catecholamine Synthesis and Use of Drugs

1. Metyrosine (also called α-Methyl-p-tyrosine) - Inhibits tyrosine hydroxylase (TH) competitively - competes with tyrosine for TH - Decreases NE and EPI synthesis in periphery and CNS Drug Use - Can be used as adjunctive therapy for NE/EPI/catecholamine secreting tumors (pheochromocytomas), and before surgery to remove the tumor - Why is TH the best target to inhibit catecholamine synthesis? --> rate limiting step/enzyme in production of catecholamines, cannot make catecholamines without this enzyme 2. L-DOPA - increases synthesis of all catecholamines in CNS, as well as in peripheral tissues - L-DOPA bypasses TH - Increases synthesis of catecholamines by providing a substrate beyond the rate-limiting step Drug Use 1. Parkinson's disease: most important (>40 yrs) - Disease of loss of dopaminergic neurons in CNS - Increases dopamine - Why not give DA to treat Parkinson's disease? --> DA does not cross BBB, but DOPA can cross the BBB and then can be converted to DA 2. Rare conditions of TH deficiency What does L-DOPA do to TH activity? - probably decreases TH activity due to negative feedback inhibition of DA and NE

Cell Death

1. Necrosis: - pathologic process - cell is irreversibly injured - unable to maintain membrane integrity - undergoes progressive enzymatic degradation - Accidental and/or unregulated form of cell death that results from membrane damage and loss of ion homeostasis - triggers inflammatory response due to release of cellular contents 2. Apoptosis: - Programmed cell death - physiologic or pathologic usually secondary to DNA damage - characterized by nuclear dissolution without the complete loss of membrane integrity - does not trigger an inflammatory response

Drug Receptors

1. Neurotransmitter or hormone receptors (most common) - Proteins: genes cloned, sequenced, identified (mostly) - General classes: i. Ion channels (e.g. nicotinic cholinergic, glutamate, GABA) ions - sodium, potassium, calcium, chloride ii. G protein coupled (e.g. adrenergic, muscarinic) second messengers - cAMP, IP3, prostaglandins iii. Growth factor (e.g. EGF) & Cytokine (e.g. interferon) protein kinase activity - phosphorylated proteins (RTKs) iv. Transcription factor (e.g. estrogen) transcriptional regulation (nuclear receptor) 2. Enzymes - HMG-CoA, PDE, MEK, cholinesterase 3. Protein-Protein interactions - bcr-abl, EWS-Fli-1BCL2-BH3 binding (Venetoclax for CLL) 4. DNA or RNA - siRNA, antisense - delivery is difficult but the promise of specificity is extreme - look for these in the future

Drugs that Inhibit Metabolism of Catecholamines: Monoamine Oxidase (MAO) Inhibitors

1. Phenelzine, Isocarboxazid, Tranylcypromine - Non-selective - used as antidepressants, not usually first-line treatments - All restrictions apply 2. Selegiline (Deprenyl) - Selective for MAO-B. - Used in adjust in treatment of Parkinson's disease. - Because of the selective inhibition, remaining MAO-A enzyme in the periphery can continue to metabolize tyramine and other drugs - Therefore, fewer drug and food interactions; nevertheless, some interactions may occur

Proto-oncogene Activation Mechanism: 1. Point Mutation

1. Point mutation: - Activating or gain of function mutations, usually somatic Point mutation of RAS family genes are an example and a very common abnormality in human tumors - GTPase involved in signal transduction that can be mutated to become constitutively active --> self sufficiency in growth signals - - pancreatic adenocarcinoma, cholangiocarcinoma, colon carcinoma, endometrial carcinoma, lung and thyroid carcinoma

Selective α-adrenergic Receptor Antagonists (Blockers)

1. Prazosin: a1 a, b, d - competitive antagonist approximately 100X more potent at alpha-1 than alpha-2 receptors - Useful as an antihypertensive drug - produces less reflex tachycardia than nonselective agents (not getting blockade at a2A presynaptic receptors that would have caused more NE release to heart, TG!) - Side effect: orthostatic hypotension but usually only with first few doses. 1. Tamsulosin a1A selective - useful for treating benign prostatic hyperplasia (BPH) - cause relaxation of smooth muscle in the prostate, the trigone muscle of bladder and urethra. - This drug is α1A selective, so it usually produces less orthostatic hypotension at therapeutic doses. - now classic example of how knowledge of alpha-1 receptor subtypes can lead to better therapy

Drugs that Disrupts Storage Vesicles

1. Reserpine - Blocks vesicular monoamine transporter (VMAT-2) on storage vesicles for catecholamines (NE, EPI, DA) and serotonin (5-HT) - leads to depletion of these biogenic amines in peripheral tissues and CNS How does interrupting storage vesicles lead to depletion? - By enzymatic oxidation by MAO Drug Use - Reserpine was one of the first drugs widely used to treat hypertension - Seldom used today because of severe side effects, (sedation, depression, GI problems) - has been replaced by much more specific and better drugs in most of the world Of great historical importance: - Used to treat "madness" in India ~500 years ago. It is very sedating - One of the earliest drugs for treating psychoses (1940s) and then for and early drug for hypertension - advanced our understanding of hypertension, depression, and schizophrenia It taught us a lot about CNS disorders

Termination of the Effect of Catecholamines

1. Reuptake into nerve terminal is primary mechanism for termination of effect - Transporters exist for DA, NE, 5-HT (NET = NE transporter) - Once inside nerve terminal, the transmitter is taken up by vesicles or broken down by enzymes (MAO) - Transporters will transport drugs that have effects inside the cell (eg., tyramine, ephedrine and amphetamine enter the nerve terminal and increase release of NE). - Drugs can block the reuptake pump thereby increasing the effect of released transmitter (eg., cocaine and tricyclic antidepressants). 2. Uptake into target cell or other tissues/organs followed by metabolism by catechol-O-methyltransferase (COMT) - location of COMT is mainly extraneuronal (gut, liver, kidney, brain). - renders catecholamines ineffective orally since they are metabolized before significant systemic absorption occurs. - COMT metabolizes circulating catecholamines (EPI). - Drugs that inhibit COMT (eg., entacapone) increase concentration of circulating catecholamines - These drugs are used for Parkinson's Disease to increase DA. 3. Metabolism by MAO and COMT - Monoamine oxidase is located on outer surface of mitochondria in sympathetic nerves, liver, GI, kidneys. - Drugs that inhibit MAO (eg., phenelzine and selegiline) increase concentration of specific transmitters (NE, 5-HT or DA) in nerve terminal. 4. Diffusion from synapse

Release of Norepinephrine (and most other NTs)

1. Storage vesicles are filled and dock near axon terminal (active zone) 2. Depolarization of axon terminal (nerve ending) triggers opening of voltage-gated Ca2+ channels 3. Calcium enters through these channels 4. Ca2+ entry promotes docking and fusion* of the storage vesicles with plasma membrane Release of transmitter occurs by exocytosis Transmitter diffuses into the synaptic cleft (100 Å) ***Docking and fusion processes require ATP-dependent interactions between: - specialized Vesicle Associated Membrane Proteins (VAMPs) on storage vesicles - specialized Synaptosomal Nerve-Associated Proteins (SNAPs) on plasma membrane Note: Other components of vesicle, including co-transmitters can also be released (depending on factors such as firing frequency) Note: presynaptic receptors on axon terminal & cell body α-2A and α-2C Note: recapture of vesicle membrane by endocytosis followed by recycling of vesicles - Mutations of a vesicle protein synaptophysin involved in endocytosis are implicated in certain developmental intellectual disabilities.

Theory and Assumptions of Drug-Receptor Interactions

1. The binding of a drug to the receptor causes some event which leads to a response - D + R <--> DR => event => response - Event is a conformational change required for activation of the receptor - The drug: causes a conformational change OR binds to a preferred conformation 2. The response to the drug is graded (i.e. is dose-dependent) - increase in drug concentration --> increase in response - hyperbolic (reaches plateau at Emax) 3. The drug-receptor interaction follows mass-action relationships - only one drug molecule occupies each receptor site - binding is reversible - Mass action => increasing something on left drives reaction to the right and vice versa - D + R <--> DR - Kd = (D)(R)/(DR) --> equilibrium dissociation constant 4. For a given drug, magnitude of the response is directly proportional to fraction of the total receptor sites occupied by drug - occupancy assumption - defines a 'simple system' - (DR)/(Rt) = E/Emax 5. Number of drug molecules >>> the number of receptors. - keep the math simple - Most of the time it is true - same assumption is made for Michaelis-Menten - What this means is that as (D) increases, free receptors (R) decrease, but free (D) does not

Antibodies: Three Main Mechanisms of Defense

1. neutralization 2. opsonization 3. complement-mediated lysis. Neutralization - process by which antibodies can block antigens from binding to cellular receptors - antigens may be exotoxins, virus particles - Antibodies combine with antigens to form immune complexes that are removed and disposed of by macrophages Opsonization - ability of antibodies to bind to antigens and provide handles (Fc portion) that can be grasped by professional phagocytes and other cells - These receptors are called Fc receptors. Complement activation and lysis - classical pathway of complement cascade can be activated by both IgM and IgG - allows antibody binding to result in microbe lysis

Proto-oncogene Activation Mechanism: 2. Chromosomal Translocation: fusion protein

2. Chromosomal translocation: fusion protein - Involves transfer of a portion of one chromosome to another - Many tumors have known translocations: used to confirm diagnosis - Philadelphia (Ph) chromosome t(9;22) well known example in patients with chronic myelogeneous leukemia (CML) - Translocation activates c-ABL proto-oncogene (protein kinase) - resultant BCR/ABL oncogene has very high tyrosine kinase activity ABL is a cytoplasmic non-receptor tyrosine kinase After ABL/BCR fusion - ABL becomes very active! **Good target for therapy since this fusion protein does not exist in normal cells (only cancer cells)

Direct Adrenergic Receptor Agonists: Norepinephrine

2. Norepinephrine Stimulates 9 alpha and beta receptors (beta-1 >> beta-2): essentially does not stimulate beta-2 - Limited clinical use due to its rapid reuptake, and its potent vasoconstrictive effects. Epinephrine vs NE - Question: Why is Epi used more often than NE? - Answer: Better CO and Organ Perfusion (increased contractility (SV) and HR --> increase in systolic BP) Exceptions: Norepi is useful in septic shock and other severe hypotensive states (e.g., anesthesia) - even though it does not increase CO very much, the increased cardiac force (contractility) and BP increase perfusion pressure without increasing heart rate - increased HR is not desirable in these cases because of chance of cardiac arrhythmia - Here, NE is useful to maintain perfusion pressure without increased HR Why is HR usually increased less by NE than by Epi? - baroreceptor reflex due rapid increase in diastolic BP via alpha-mediated vasoconstriction (norepi) leading to decreased HR via vagal nerve stimulation Would the presence of atropine change the effects of NE on cardiac output? How? By what mechanism? - atropine: muscarinic antagonist, would block cardioinhibitory reflex - By blocking muscarinic receptors, atropine would block baroreceptor-induced vagus stimulation and would therefore increase the heart rate - result would be that cardiac output would increase How are the actions of injected Epi and NE terminated? - High affinity uptake into nerves and lower affinity uptake into other tissues, such as heart.

Proto-oncogene Activation Mechanism: 3. Chromosomal Translocation: increased promotor

3. Chromosomal translocation: increased promoter activity - Proto-type is Burkitt lymphoma (a mature B cell lymphoma/leukemia) involving c-myc proto-oncogene, t(8;14) - C-myc gene is translocated next to a promotor gene that controls transcription of immunoglobulin heavy and light chains --> leads to over production of a normal C-myc product leading to the emergence of a dominant clone - C-myc is involved in cell cycle regulation

Direct Adrenergic Receptor Agonists: Isoproterenol

3. Isoproterenol Not a catecholamine but similar structure Potent beta-1 and beta-2 selective agonist (essentially no alpha effects) Not a substrate for reuptake or for MAO so its duration of action is longer than NE or EPI, but is still brief due to COMT metabolism

Nicotinic Agonists

Acetylcholine Nicotine - smoking cessation

Direct Adrenergic Receptor Agonists: Dopamine

4. Dopamine Stimulates D1 receptor >> beta-1 > alpha-1 Low dose: D1 effects --> dilation of renal/mesenteric vasculature (coronary vessels) Moderate dose: beta-1 effects in heart (cardiac contractility) --> increase in CO High dose: alpha1 effects (vasoconstriction), moderates HR (slight baroreceptor reflex like epi) too high can override renal/mesenteric vasodilation This separation of effects by dose makes it useful in some cases of shock because it can increase CO (beta-1) while preserving renal function (D1) Dopamine induced increase in cardiac output could occur via: - partial agonist activity at beta-adrenergic receptors - DA may increase NE release at synapses in heart by 1) by activating D-1 receptors on NE axon terminals and 2) competing for and therefore inhibiting NE re-uptake How can Dopamine by Useful? DA and NE given by Infusion: - Note: DA increases HR and CO via β-adrenergic receptors, while increasing renal, mesenteric and coronary blood flow via D1 receptors. - However, note that at higher doses, the dilating effects via D1 can be somewhat offset by the α1 effects (vasoconstriction)

Proto-oncogene Activation Mechanism: Gene Amplification

4. Gene amplification - Chromosomal abnormality that results in increased number of gene copies. Examples: - Erb B2 (HER2/neu) amplified in breast/ovarian carcinoma (too many HER2 receptors expressed in membrane) - N-myc- amplified in 40% of neuroblastomas Often implies a poor prognosis

Inverse Agonists

4. If D has low affinity (Kd=1mM) for R* and high affinity (Kd=1 nM) for R Receptor ratio R/R* is 99/1 - will look like a neutral/competitive antagonist If the initial receptor ratio R/R* is 6:4 - receptor is active without agonist - receptor has constitutive activity in absence of agonist - active receptor elicits effect/response is absence of agonist Inverse agonist will pull receptor ratio towards the inactive/resting conformation R leading to an opposite effect of the agonist - decrease the constitutive activity

Heavy Chain Isotypes

5 isotypes (or classes) of HC based on the aa sequences of their constant regions: - mu - gamma - alpha - delta - epsilon Each antibody contains 2 identical HC Antibodies can contain either 2 kappa or 2 lambda LC gamma HC: IgG, 4 subclasses of gamma HC: gamma1/IgG1, gamma2/IgG2, gamma3/IgG3, and gamma4/IgG4 alpha HC: IgA, 2 subclasses of alpha HC (IgA1 and IgA2). delta HC: IgD epsilon HC = IgE

Direct Adrenergic Receptor Agonists: Dobutamine

5. Dobutamine Stimulates beta-1 > beta-2 with weak alpha-1 stimulation Selective β1-Adrenergic Agonist Less activation of vasodilator β2 receptors and modest activation α1 receptors --> less reflex tachycardia via baroreceptors (less cardioacceletory reflex b/c B2 vasodilation is not active) Results in a favorable, relatively greater increase in force of cardiac contraction (contractility) compared to HR increase t1/2 ~2 min: given by continuous i.v. infusion Racemic mixture: (+) β1 agonist and α1 antagonist; (-) is α1 agonist. - Less reflex tachycardia How? Doesn't directly lower TPR (no B2 effects) - Greater inotropic vs chronotropic effect --> heart is more efficient: working less for same CO - inotropic: contractility, SV - chronotropic: HR Decreased Response (tachyphylaxis) to Dobutamine is sometimes seen in heart failure patients treated chronically for long periods Mechanisms: - Receptor Desensitization - Receptor Down-regulation

Amyloidosis: Chemical Properties

95% consists of fibril proteins. 5% consists of a glycoprotein - P component - also referred to serum amyloid P or SAP - protein component is bound to all amyloid fibrils and may have some scavenging function or may have a role stabilizing the fibril. 15 chemically distinct types of amyloid proteins The following will be discussed in more detail in association with the clinical disease: - AL (immunoglobulin light chain) - AA (non-immunoglobulin protein synthesized in the liver) - TTR (transthyretin) - beta2-microglobulin - beta-amyloid protein

Ecchymoses

> 1-2 cm Subcutaneous hemorrhages often associated with trauma Bruises may change colors clinically as red blood cells are degraded and resorbed.

Neoplasia: Cecum Adenoma

Adenoma: benign neoplasm of glandular tissue. Multiple adenomas of the cecum are seen here in a case of familial polyposis Tubular adenoma (polyp) - growth into the lumen - Tubular adenomas are neoplastic with dyplastic growth

Antigen Binding

A small antigen like a hapten often binds in a pocket in the antigen binding site A large antigen, like a protein or polysaccharide, might interact with the antigen binding site over an extended surface An antibody recognizes only a part of a large molecule called an epitope (or antigenic determinant) - epitope may be composed of aa in a linear sequence or aa from different regions of the protein that are brought together in the native protein structure (conformational epitope) - linear epitope vs. conformational epitope Forces that hold an antigen and antibody together are noncovalent so the interaction can be formed and broken: - van der Waals - hydrogen bonds - hydrophobic interactions - electrostatic) Affinity: Strength of interactions b/w an antigen and a single antibody binding site Avidity: Total strength of the interaction b/w an antibody and its antigen and it relates to the number of antigen binding sites on the antibody - 2 on IgG, 10 on IgM pentamer, 4 on IgA dimer Cross-reactivity: means that an antibody specific for one antigen is able to bind another, different antigen - results when two epitopes have similar structures so both are complementary to the antibody binding site. Antigen binding sites of different antibodies are unique in their 3D shape and chemical characteristics: - due to differences in lengths of HVR loops and - due to differences in the characteristics of the amino acids found in these loops - amino acids dictate hydrophobicity, charge and shape of antigen binding site - Because binding sites of different antibodies have different amino acid sequences, each antibody is specific for a different antigenic determinant (epitope) - Binding site is complementary to its antigen (specifically to its antigenic determinant or epitope) - better the fit --> higher the affinity antibody has for its antigen Hypothesized that every individual can generate antibodies carrying antigen binding sites complementary to any antigen that might be encountered in the lifetime of an individual. Literally a billion different antibodies might be available to our immune system, each binding site highly specific for its antigen in shape, charge and hydrophobicity

Thrombosis Pathology

A thrombus can form anywhere in vascular system (venous and arterial) or heart. Most thrombi originate at site of vascular injury and are firmly attached to vessel wall or heart wall. Propagating tail may not be attached and break off forming an embolus. Microscopic: - Composed of alternating areas of platelets, fibrin and RBCs - Some degenerating leukocytes may be present.

Overview of ACh and cholinergic receptors

ACh release from preganglionic neurons of SNS and PNS Nicotinic neuronal (Nn) receptors (ionotropic) on postganglioinc cells bodies (in the ganglia) of SNS and PNS ACh released from postganglionic neurons of PNS Muscarinic receptors (GPCR) on effector organs of PNS ACh released from postoganglionc neuron going to sweat glands in the SNS Muscarinic receptors on sweat glands of the SNS ACh released from somatic (voluntary) motor neuron Nicotinic muscular (Nm) receptors on effector muscles

Organophosphates Toxic Effects - Nerve Agents

AChE inhibitors extreme levels of ACh is all the cholinergic synapses Symptoms - Pupillary constriction - Lacrimation - Runny nose - Sweating - Drooling - Vomiting - Urination - Defecation - Bronchoconstriction - Tracheal secretions - Hypotension - Cardiac slowing - Seizures - Unconsciousness - Respiratory paralysis - Suffocation Death can occur within three minutes Treatment - Immediately administer antidote - Remove and wash clothing with bleach - Wash body with diluted bleach - Irrigate eyes - Monitor airway, breathing and circulation Antidote - Atropine: antimuscarinic --> Counteracts effects on brain, heart, trachea and gastrointestinal tract - Pralidoxime: Breaks the bond between the nerve agent and cholinesterase, strong nucleophile rendering cholinesterase active again to break down ACh - could also give a ganglionic blocker

BCR vs TCR binding to antigen

ANTIBODY (BCR) BINDS AN ANTIGEN DIRECTLY T-CELL RECEPTOR (TCR) BINDS A COMPLEX OF ANTIGEN FRAGMENT AND SELF MOLECULE (MHC) Antibodies are much more flexible in their ability to bind antigen than are TCRs Paratope of the antibody (BCR) molecule can bind conformational epitopes (folding of native proteins) and linear epitopes Paratope of TCR molecule binds linear epitopes Antibodies generally bind hydrophilic epitopes on solvent exposed surface of the antigen TCRs recognize linear peptides from the internal hydrophobic regions of proteins.

Mechanisms of Cell Injury

ATP depletion: - Hypoxic injury and chemical injury can interfere with normal ATP production - Direct results of this interference lead to deregulation of the sodium-potassium pump, calcium homeostasis, disruption of protein synthesis and the unfolded protein response. Mitochondrial damage: - When the mitochondria become damaged, often it means death for the cell. - Abnormal calcium levels, oxidative stresses, lipid peroxidation can lead to mitochondrial abnormalities - manifest by increasing porosity of the inner mitochondrial membrane - cannot maintain normal oxidative phosphorylation. Abnormal calcium homeostasis: - Abnormal increases in intracellular calcium lead to increasing membrane permeability - can activate a variety of abnormal enzymatic reactions and induce apoptosis. Accumulation of oxygen radicals/oxidative damage: - Partially reduced oxygen formed as a by-product of metabolism can be considered a reactive oxygen species - Damage is initiated by certain stimuli: radiant energy, exogeneous chemicals and drugs, some metals and nitric oxide - Cell injury occurs via lipid peroxidation of cell membranes, abnormal modification of proteins and direct DNA damage. Loss of membrane integrity

IgG: Blood and Extravascular Sites

Ability of antibodies to bind Fc receptors (FcR) on phagocytes is important in removal and destruction of pathogens Certain cell types express FcR specific for particular classes or subclasses of antibody Fc Receptors bind to exposed Fc portion of the antibody while the Fab portion is bound to antigen Antibody:antigen complex is endocytosed and degraded within the phagocyte. NK cells also have Fc receptors and will mediate antibody-dependent cellular cytotoxicity (ADCC).

Neurotransmitters of the Sympathetic Nervous System Review

Acetylcholine (cholinergic neurons): 1. preganglionic neurons of SNS (and PNS) 2. preganglionic neurons of SNS that innervate adrenal medulla 3. postganglionic neurons of the SNS that innervate sweat glands - sympathetic cholinergic fibers (special case) Norepinephrine (adrenergic neurons) and Epinephrine: 1. postganglionic neurons of SNS release norepinephrine 2. adrenal medulla secretes: - norepinephrine - 20% - epinephrine - 80%

Activation of Classical Complement Cascade: IgM

Ability to bind complement and activate complement cascade is an important function of antibodies to aid in ridding the body of pathogens Binding of complement requires that the antigen-bound Ig have constant regions from two adjacent monomers near one another End result is destruction of the antigen to which the antibodies are bound IgM is able to activate complement: - most effective Ig in fixing complement because of its pentamer structure - automatically has 2 monomers next to one another - Note that IgM cannot bind complement until it has bound antigen (conformational change), a form of regulation of complement activation

IgG: Activation of Classical Complement Cascade

Ability to bind complement and activate the complement cascade is animportant function of antibodies to aid in ridding the body of pathogens. Binding of complement requires that the antigen-bound Ig have the constant regions of two Ig monomers near one another Requires a certain density of antigen and IgG binding in order to trigger complement - Thus IgG is not as good as activating complement as the IgM pentamer

Calcification

Abnormal accumulation of calcium salts within tissue Occurs in a variety of pathologic states Firm and chalky on gross examination Appears blue/purplish on H&E stained slides (the calcification looks the same for both dystrophic and metastatic) Calcification is subcategorized as: - Dystrophic: occurs in abnormal tissues; underlying disease. Examples: atherosclerotic vessels, tumor necrosis - Metastatic: Occurs in patients with systemic hypercalcemia and normal tissues.

Complications of Acute Inflammation

Abscess: - area of pus with underlying tissue destruction - collection of acute inflammatory cells (that make up the pus) is characteristically walled off (by attempted repair process around abscess) making it more difficult to treat with systemic antibiotics - Abscesses often need to be surgically drained. Ulcer: - superficial epidermal or mucosal defect - skin or epithelium is sloughed off (falls off) - area directly underneath defect contains numerous neutrophils, cellular debris and fibrin - deeper areas consist of macrophages, new vessels and fibroblasts indicative of repair - Ulcers can be found on any mucosal surface and on the skin.

Brief Overview of Pharmacokinetics

Absorption Distribution Metabolism Elimination Cmax = max. plasma concentration Tmax = time of Cmax AUC = area under the curve T1/2 = half-life of elimination (how long does it take to eliminate 50% of the drug?)

Cellular Accumulations

Accumulation of a substance may occur in the cytoplasm, nucleus or organelle - may be produced in cell or outside of cell - a few organelles respond to both acute and chronic injury with interesting and specific morphologic changes - Many of these abnormalities occur with certain diseases and can be detected on light microscopy as 'bodies', accumulations or inclusions Lysosomes: - contain hydrolytic enzymes used in breakdown of phagocytosed material - act as a site for materials that the cell cannot properly metabolize - in some patients with lysosomal storage diseases (caused by a variety of enzyme deficiencies), these may become abnormally large and cause problems. Endoplasmic reticulum: - smooth ER is metabolizes certain substances (especially drugs in the liver) - If a patient is taking a drug that utilizes the smooth ER, the consequence is increased numbers and enlargement. Mitochondria: - Mitochondrial abnormalities can be seen in several diseases and can be altered in number, size and shape. - mitochondrial myopathies are disease of skeletal muscle. Cytoskeleton: - Thick, thin and intermediate filaments are present within the cytoskeleton. - Certain toxins, drugs and genetic diseases can lead to alterations of the cytoskeleton.

Hemopericardium

Accumulation of blood in pericardial spaces Often secondary to rupture of the aorta (from aortic aneurysm or trauma)

Hemothorax

Accumulation of blood in pleural spaces

Hemarthoses

Accumulation of blood in the joint space

Hematoma

Accumulation of blood within a tissue

Muscarinic Agonists

Acetylcholine Methacholine - B methyl group - makes it more specific to muscarinic receptors (4.4A) - helps to hinder hydrolysis by cholinesterase - only use in medicine --> diagnostic tool b/w asthma and COPD Carbachol - resistant to hydrolysis by cholinesterase because of terminal NH2 - decrease intraocular pressure --> treat glaucoma (open up a canal??) Bethanechol - activate muscarinic receptors tract after surgery (typically constipated) - iliac paralysis - restores GI function

Cholinergic Receptor

Acetylcholine takes on two known conformations - can rotate around its access Two charged centers are: 4.4A aparts --> Muscarinic conformation (low energy conformation) - muscarine has two charged centers 4.4A apart - binds to muscarinic receptors Two charged centers are: 5.9A aparts --> Nicotinic Conformation (high energy conformation - nicotine has two charged centers 5.9A apart - binds to nicotinic receptors

Hyperemia

Active process in which arteriolar dilation leads to increased blood flow Affected tissues typically turn red

Clinical Example: Acute vs. Chronic Hemorrhage

Acute hemorrhage: - 22 year-old man is involved in a motor vehicle accident with subsequent blunt trauma to the chest - ruptured ventricle and hemopericardium result in increased pressure within the pericardial space - heart cannot pump against this pressure, tamponade and death ensue (obstructive shock) Chronic hemorrhage: - 62 year-old woman with hemoglobin of 8 g/dL - Colonoscopy reveals a tumor of large intestine and stool that is positive for blood - GI tract is a common anatomic site for chronic blood loss - patient may not know that they are bleeding, but feel tired (anemic, slow chronic blood loss)

Acute vs. Chronic Inflammation

Acute inflammation: - Rapid onset - short duration (hours to days) - fluid accumulation (edema) - neutrophils Chronic inflammation: - Variable onset - longer duration (weeks, months, years) - macrophages and lymphocytes - new vessel formation and fibrosis

Hemodynamics: Renal Infarction

Acute renal infarction Note: - wedge shape of this zone of coagulative necrosis - resulting from loss of blood supply with resultant tissue ischemia that produces the pale infarct The small amount of blood supply from the capsule supplies the immediate subcortical zone The remaining cortex is congested, as is the medulla.

Cellular Adaptation

Adaptations of cellular growth and differentiation Defined as an altered steady state secondary to external stress (cannot return back to initial/baseline steady state, adapts to a new homeostasis) - Changes are reversible and may include change in size, number, cell type, metabolic activity or function - Cellular adaptation can be either physiologic (considered a 'normal' response and often temporary) or pathologic (considered an abnormal response and one that often needs to be addressed clinically) Cellular adaptations: 1. hypertrophy 2. hyperplasia 3. atrophy 4. metaplasia

Malignant Tumors

Add 'oma' with a few more rules Cancer usually refers to a malignant neoplasm Malignant tumors, by definition, have the ability to: - invade (break through the basement membrane) - metastasize (travel to distant sites via lymphatic vessels, blood vessels) General Characteristics: - growth may be slow or rapid - ill defined (not well circumscribed, pseudopods) - nonencapsulated Malignant tumors of epithelial tissues are referred to as carcinomas --> identify by keratin production - Glandular malignancies: adenocarcinoma (liver, lungs, GI) - Squamous malignancies: squamous cell carcinoma (skin, mucosal surfaces) - Small Cell/Neuroendocrine (lung, prostate) Common to include tissue of origin: - Hepatocellular carcinoma (adenocarcinoma in the liver) Secondary qualifiers are also common: - Papillary serous cystadenocarcinoma (ovary) Malignant tumors of mesenchymal tissues are referred to as sarcomas --> identify by vimentin production - Leiomyosarcoma (Malignant tumor of smooth muscle) --> desmin production - Rhabdomyosarcoma (Malignant tumor of skeletal muscle) --> desmin production - Osteosarcoma (Malignant tumor of bone) - Liposacroma Blastoma (primitive, small round blue cell tumors of childhood) neural/neurofilament production Lymphoma (malignant tumors of lymphoid tissue/lymphocytes, B and T-cell neoplasms) Melanoma (malignant tumor of melanocytes, neural crest origin ) Gliomas (tumors primary to the CNS, do not metastasize beyond CNS, but considered malignant) --> glial fibrillary acidic protein (GFAP) Seminoma (malignant tumor of testis) Degree of differentiation: Some malignant tumors are further qualified by assessing how closely they resemble presumed tissue of origin (predictor of cancer aggressiveness) - Well differentiated: closely resembles tissue of origin - Moderately differentiated: less closely resembles tissue of origin - Poorly differentiated: barely resembles tissue of origin - Undifferentiated: tumor cells do not resemble any tissue of origin Other terms: - Anaplasia: Lack of differentiation - Pleomorphism: Variation in size and shape of the cell and/or the nucleus Tumors of the brain are also exceptional: - no clear cut distinction between benign and malignant.

Drug Effects: Additivity vs. Synergism

Additivity: - If two drugs work at the orthosteric site of the same receptor, and are given at less than maximal dose/concentration, their effects will add Synergism: - Two drugs, acting on distinct sites or receptors whose actions potentiate the effect of the other drug will be synergistic Examples of Synergy Mechanisms: 1. Inhibitor of serotonin uptake & serotonin released from neurons 2. Inhibitor of acetylcholinesterase & acetylcholine released from neurons 3. Benzodiazepines, acting allosterically, & GABA released from neurons - Benzodiazepines increase the frequency of the chloride ion channel opening, thereby increasing the inhibitory effect of GABA on neuronal excitability - PAM of GABA channel 4. Probenecid and Penicillin - 1st inhibits the tubular secretion of the 2nd, prolonging action.

Resuscitation: Vasopressors in Septic Shock

Adrenergic agonists are first line: - rapid onset - high potency - short half-life Alpha Adrenergic Agonists: - Receptors located in vascular walls - increase vascular tone (TPR) and BP - also decreases CO (reflexive bradycardia)and impair tissue blood flow Beta Adrenergic Agonists: - Beta 1: most common in heart, mediate increases in inotropy (contractility) and chronotropy (rate) - Beta 2: in blood vessels induces vasodilation (think b-agonists like albuterol: asthma) - Overall B-adrenergic stimulation: increase blood flow but increased risk of ischemia given increased HR and contractility Dopamine agonists: - DA receptors: renal, mesenteric, coronary, cerebral vascular beds - Low dose DA: leads to vasodilation (particularly renal/mesenteric) - High dose DA: stimulates alpha-1 receptors leading to vasoconstriction Common Vasopressors in Sepsis: - Norepinephrine: predominantly alpha adrenergic, but modest beta adrenergic - Dopamine: predominantly beta adrenergic at lower doses and alpha at higher doses - Epinephrine: predominantly beta effects at low dose, alpha effects increasing with higher doses. - Phenylephrine: pure alpha adrenergic activity Side Effects of Vasopressors: Use just enough to restore tissue perfusion without excessive peripheral arterial vasoconstriction (TPR) leading to tissue hypoxia and necrosis Surviving Sepsis Guidelines: - Norepinephrine as first choice vasopressor - Epinephrine as an additional agent if needed - Avoid Dopamine except in carefully selected patients

Log Dose-Response Curve

Advantages of expression as log(drug) versus response. 1. Dose-response relationship expressed as a nearly straight line over a large range of drug doses. 2. Wide range of doses can be plotted on a single graph, allowing easy comparison of different drugs. Hyperbolic Saturation Curve --> Sigmoidal Saturation Curve

Orthosteric vs Allosteric Diagram

Affinity modulation --> Effects EC50 --> potency Efficacy modulation --> Effects Emax --> efficacy - modulator may effect affinity, efficacy or both

Heavy Chain Isotype Switching

After leaving the BM: - B cell expresses IgM and simultaneously express IgD when the locus synthesizes a very long RNA transcript After encounter with antigen - class switch can occur - B cell can express either IgG, IgA, IgE Antibodies that are produced carry the same antigen binding specificity as the original B cell (VDJ HC Variable region) (+/- somatic hypermutation) Isotype switch process only alters the effector functions of the antibody by changing the class of antibody produced LC remains the same (no change in constant region or variable region)

Selective Beta2 adrenergic receptor agonists

Albuterol - bronchi Ritodrine - bronchi, uterus Terbutaline - bronchi Therapeutic use: Bronchodilation - To treat asthma/bronchospasm: Albuterol, Terbutaline - Often delivered to site of action by inhalation to reduce systemic side effects. - Less cardiac stimulation than nonselective agents such as epi and iso which also stimulated B1 in the heart - (What accounts for the cardiac effects of b2 agonists? There are, in fact, b2 adrenergic receptors in myocardium β2 agonists were once thought to reduce premature contractions of pregnant uterus: - No longer because they were not very effective and risk/benefit for this purpose wasn't favorable. - it is interesting that the pregnant uterus responds more than non-pregnant uterus. This is probably an example of influence of hormones on receptor expression in specific tissues.)

Nicotinic Antagonists

All competitive blockers Nn antagonists: ganglionic blocking drugs (and at adrenal medulla) - Nn antagonist have N 6 carbons apart to block receptor binding sit - Hexamethonium - Trimethaphan - cuts off autonomic nervous system Nm antagonists: muscle relaxants - block NMJ Nm receptors at motor end plate (end plate potential gets smaller and smaller --> causes paralysis - flaccidity) - 10 carbon apart anionic binding sites for positively charged N at Nm receptors - Nm antagonists have N 10 carbons apart - Curare

General Supportive Care

All critically ill patients receive best practices: - blood glucose management - provision of fluids - Prophylaxis for thromboembolism - Stress ulcer prophylaxis for GIB prevention - Oral or enteral feeding early - Physical therapy early and for duration - Address goals of care always

Therapeutic Index

All drugs are poisons and what separates a poison from a drug is dose The only drug that doesn't have a side effect is the one that just came on the market How do we measure 'toxicity' of drugs? Big Question: What dose do we give a person to achieve a therapeutic response and avoid a toxic response? Method of expressing comparison of therapeutic dose to toxic dose - T.I. = TxD50/ED50 - The larger the T.I. the safer the drug This works well if the dose/response curves are parallel. - But, if they are not...Standard Margin of Safety is used. - SMS = TxD1/ED99 - dose that negatively affects 1% of the population over the dose that positively affects 99% of the population

Catecholamine Degradation/Metabolic Pathway

All mitochondria contain MAO on their outer membranes: enzyme is abundant all cells including in nerve terminals At least 2 types of MAO: MAO-A and MAO-B Catecholamines are metabolized by: 1. monoamine oxidase (MAO)2 2. catechol-o-methyltransferase (COMT) Monoamine oxidase metabolizes neurotransmitters NE, EPI, DA, Serotonin (5-HT), and other biogenic amines MAO inhibitors allow concentrations of biogenic amine neurotransmitters to increase in cytoplasm in nerve terminal and can increase release of these transmitters - inhibit degradation/metabolism of these NTs leading to increased amounts, and increased release of them Drug Uses - drugs can be useful for treating some types of depressions and as an adjunct in Parkinson's disease (inhibit degradation of DA from L-DOPA provided to relieve symptoms)

Origin of Cellular Elements of the Immune System

All of the cells in the immune system originate from a pluripotent stem cell in the bone marrow Pluripotent hematopoietic stem cell gives rise to several types of progenitor cells under the influence of cytokines, chemokines, cell adhesion molecules and transcription factors. ILC = innate lymphoid cell Note that dendritic cells (DCs) can come from both the lymphoid progenitor and the myeloid progenitor - DCs can also come from various other cells such as fibroblasts attesting to the plasticity of cells.

Inheritance of Allotypes

Alleles are inherited in families and individuals may be: - homozygous (carrying 2 copies of one allele Km(1)+Km(1) - heterozygous (carrying 1 copy of one allele and 1 copy of another allele, Km(1)+Km(2) Children inherit one of the two alleles carried by each parent - 4 possible sibling combinations - is a 1 in 4 chance that a sibling inherits the same two alleles as another sibling

Adrenergic Receptor Subtypes and Potencies to NE and EPI

Alpha1 receptors - Gq coupled to PLC activation - PLC cleaves PIP2 into IP3 and DAG - IP3 binds to ER to cause Ca++ release - Ca2+ secondary messenger can go to elicit effects on other proteins (Ca2+-calmodulin, w/DAG --> PKC) - (EPI >= NE) - Alpha1 receptors mediate primarily excitatory smooth muscle responses - contraction of vascular muscle, GI and bladder sphincters, radial muscle, pilomotor muscle - alpha1A subtype predominates in prostate smooth muscle Beta1 receptors - Gs coupled to adenylyl cyclase: increase cAMP - (EPI = NE) Beta2 receptors - Gs coupled to adenylyl cyclase: increase cAMP - (EPI >> NE) Beta3 receptors - Gs coupled to adenylyl cyclase: increase cAMP - (EPI < NE) physiological response to elevated cAMP concentration in the cell depends on the type of cell. - increased cAMP levels that occur with stimulation of either beta1 or beta2 receptors on cardiac muscle cells lead to contraction of the cardiac muscle - increased cAMP levels seen with stimulation of beta2 receptors on smooth muscle cells (bronchial, uterine, vascular, etc.) result in relaxation of smooth muscle Dopamine1 receptors - - Gs coupled to adenylyl cyclase: increase cAMP - D1 receptors are present on vascular smooth muscle cells in renal and mesenteric blood vessels - stimulation by dopamine leads to an increase in cAMP resulting in dilation of renal vascular beds and increased renal blood flow. Alpha2 receptors - Gi coupled to adenylyl cyclase: decrease cAMP - Gi has an inhibitory effect on adenylyl cyclase - (EPI >= NE) - a2 receptors are coupled to other G proteins in addition to Gi and mediate both excitatory and inhibitory responses: Alpha2A subtype (inhibitory) - located presynaptically on postganglionic sympathetic nerve terminals; stimulation results in decreased release of NE (negative feedback) - located presynaptically on cholinergic nerve terminals; stimulation (NE from SNS postganglionic collaterals) causes a decreased release of acetylcholine - located postsynaptically on cells in vasomotor center in medulla; stimulation inhibits vasomotor center leading to a decrease in sympathetic outflow to the heart (¯HR, ¯contractility), vasculature (¯TPR) and adrenal medulla (¯NE & EPI release) Alpha2B subtype - located postynaptically on vascular smooth muscle - stimulation causes vasoconstriction (TPR) mediated by a decrease in cAMP

PDE Inhibitors

Aminophylline (Theophylline) Sildenafil

Hemodynamics: Amniotic Fluid Embolism

Amniotic fluid embolism Rare complication seen at term during or shortly after labor in pregnancy resulting in sudden death Amniotic fluid may gain access to uterine veins following a tear in the placental membranes and embolize to the lungs, producing acute dyspnea with cyanosis and shock Fetal squames, lanugo hair, vernix, and mucin can embolize to small pulmonary arteries.

Amyloidosis: Pathogenesis

Amyloidosis results from abnormal folding of proteins Deposited as fibrils in a variety of organs and tissues. Abnormally folded proteins are unstable and tend to aggregate. a. May occur because of increased concentration of protein leading to tendency to fold improperly b. Mutant proteins that are inherently structurally unstable c. Proteolytic cleavage and fragmentation

Variable Region Seen as Foreign

An anti-idotypic response can occur to one's own antibodies - When a B cell encounters antigen and there is expansion of the B cell clone, a large amount of a single antibody is produced - In sufficient quantities, an immune response to the antigen combining site can occur as it is unique to that antibody - Prior to B cell expansion, the B cell and its unique Ig (unique antigen binding sites at the ends of the two Fab arms) is invisible to the immune system ("below the radar") This type of response can be significant for two reasons: 1. Has been hypothesized that this type of recognition may play a role in controlling the immune response by removing antibodies once they are no longer required. 2. Human monoclonal antibodies are preferable for use in immunotherapies because you reduce the chances of an anti-isotypic response - However, an anti-idiotypic response can occur over time reducing the effectiveness of the immunotherapy 3. anti-idiotypic reagents have been used as a treatment for B cell malignancies targeting the unique antibody found on the malignant B cell clone Three types of determinants (or epitopes) recognized during immune responses to immunoglobulins 1. Isotypic: response to species-specific determinants on constant regions of the heavy and light chains 2. Allotypic: response to allelic differences of either the variable or constant regions of the heavy and light chains within a species 3. Idiotypic: response to the variable region, specifically the antigen combining site, of an antibody.

Cardiogenic Shock

Cardiac pump failure --> resulting in decrease in cardiac output Systemic vascular resistance is typically increased in an effort to compensate for the diminished cardiac output

Neoplasia: Lymphoma Higher Magnification

Example of a large cell lymphoma Most lymphomas are of B cell origin The cells in this large cell lymphoma are polygonal and with open chromatin.

If the antagonist or inverse agonist binds at the orthosteric site...

Antagonism is competitive - antagonist binds to free receptor at active site Emax - competitive antagonism is is surmountable - Emax for agonist can be achieved with sufficient concentrations of the agonist to out compete antagonist (I) - therefore competitive antagonism at orthosteric site does not impact ability to achieve Emax EC50 is NOT A CONSTANT - Having to compete against I increases the EC50 of agonist - EC50 of agonist increases with increasing antagonist (I) concentration (affinity of receptor for agonist decreases b/c competing with antagonist) - results in shift of curve to the right - Kd = EC50 in a simple system - Kd intrinsic property of the receptor-drug pair (measure of affinity) - EC50 changes in presence of antagonists, etc. Examples: Propranolol - beta blocker Rispiridone - antipsychotic - bind orthosteric site to act as competitive antagonist What if you do an experiment that ramps up the concentration of I in presence of a saturating concentration of D (agonist) (e.g. 100xKd, 1000xKd) - IC50: conc of I that inhibits 50% of the max response - IC50 is NOT A CONSTANT - Having to compete against D increases the IC50 - Increasing saturating concentration of D increases the IC50 (decreases affinity of receptor for antagonist (I) because competing with higher concentration of the agonist (D)) - Assumption = competitive - Ki = IC50 / 1 + D/Kd

Generation of Monoclonal Antibodies

Antibodies specific for a particular antigen can be created by hybridoma technology or by recombinant DNA methods Monoclonal antibodies have multiple uses - used diagnostically to detect the level of certain cell populations such as CD4+ T cells in persons with an HIV infection - used for imaging to detect tumor antigens to monitor metastases or for therapy, for example to neutralize a toxin. Hybridoma technology: Monoclonal antibodies production: - mice are immunized with an antigen (purified protein or whole cell) - example: mouse being immunized with human T lymphocytes to make an antibody to human CD4 - After repeated exposures to the antigen, the mouse will produce antibody-secreting B cells directed against the immunogen - mouse B cells are making antibodies specific for all foreign components of the human T cells including human CD4 - These antibody-secreting B cells are short-lived. - To extend the life of the mouse B cells indefinitely, the B cells isolated from the mouse spleen are then fused in a test tube with immortal mouse myeloma cells, a malignant plasma cell line (immortalized B cells have been pre-treated to eliminate production of their own Ig) - After selection to remove unfused cells and a further cloning/selection to select hybridomas making a CD4-specific antibody, the hybridomas can be expanded indefinitely to provide an infinite source of monoclonal antibody

IgG Properties

Antibodies that contain gamma HC (IgG1, 2, 3, 4) are the major class of immunoglobulins in serum. 4 subclasses of IgG heavy chain - differ slightly in sequence of their constant regions - majority of the differences b/w subclasses are found in their hinge region where they differ in size, sequence, position, number of S-S bonds. IgG3 has a very long hinge region with 11 S-S bonds IgG1 has a much shorter hinge region with 2 S-S bonds IgG3 is more susceptible to proteolytic cleavage and has a shorter half-life b/c of long hinge region IgG1 - predominant subclass in serum with levels at least 3 times greater than any of the other IgG subclasses - better at crossing the placenta At birth, all the IgG in newborns is maternal IgG which is replaced by the baby's own IgG over the first 6 months of life Serum level and half-life e.g, about 20 days for most IgG subclasses - IgG3 has the shortest half-life in serum again likely due to its long hinge region - also is best at activating the classical complement pathway. Antibody transfer to the fetus can protect the fetus through passive immunization - potential to harm the fetus if antibodies are directed toward fetal components Other effector functions not listed include: - neutralization of pathogens - sensitization for killing by NK cells (IgG1 and IgG3). Note that IgG subclasses have a preference for specific types of antigens - IgG1 and IgG3 tend to bind proteins - IgG2 tends to bind carbohydrates - this is not always the case, always exceptions

IgM Prosperities

Antibodies w/mu HC --> IgM Found as monomers on B cell surface. When secreted: IgM is found as a pentamer - 5 monomers are linked together by interchain S-S and J or joining chain Pentamer has 10 antigen combining sites: - 2 per monomer (5 monomers) - very good at binding antigens with repeating subunits and causing agglutination (clumping) Found primarily in serum First antibody made by B cells First antibody line of defense for rapidly controlling blood infections IgM antibodies are most effective at complement activation due to the pentamer structure. Note the other properties of IgM in the table.

Schematic Structure of BCR and TCR

Antibody molecule: - antibodies (immunoglobulins) are glycoproteins consisting of four chains - two identical heavy chains (green) - two identical light chains (yellow) - heavy chains are linked together by disulfide bonds - light chains are linked to heavy chains by disulfide bonds - Each chain is divided into domains of about 110 amino acids (domains are shown as pink and blue in the figure) - pink domains are termed variable domains based on their variable amino acid sequence - variable domains of a heavy chain and its corresponding light chain form what is called the paratope: binds antigen - blue domains are termed constant domains because their amino acid sequence is more conserved - constant domains confer effector function of the antibody, that is, where it can go and what it can do - two identical paratopes to bind two identical epitopes or antigenic determinants on an antigen - antibody can be secreted from terminally differentiated B cell (plasma cell) or it can be found fixed to the B cell membrane where it is known as the BCR T-cell receptor: - TCR is a heterodimer consisting of an α and β chain or a γ and δ chains - much like one arm of the immunoglobulin molecule - TCR has variable and constant domains as does the antibody molecule and - variable domains form the paratope of TCR - TCRs recognize linear peptides that are displayed by MHC molecules - TCR paratope sees both the peptide and the MHC molecule.

Variable Region Domains

Antigen binding is a property of the variable regions of the LC and HC Each Ig monomer has two antigen binding arms (i.e., 2 Fab regions) and thus two binding sites When the aa sequences of variable regions from antibodies with different antigen binding specificities are compared, it is seen that variability is not evenly distributed throughout the variable regions - conserved regions are termed "framework regions" - sequence variation is concentrated in 3 regions in the LC and 3 regions in the HC: regions are called hypervariable regions (HVR) or complementarity determining regions (CDR) - HVRs form some of the loops that link the beta strands and are clustered at one end of the Fab region HVRs from one HC and one LC combine together to form an antigen binding site at the end of each arm of the Ig monomer

Infarction

Area of ischemic necrosis caused by occlusion of either arterial supply or venous drainage in a particular tissue. 1. Heart attack (myocardial infarction): ischemic injury of cardiac muscle in a perfusion zone of occluded artery 2. Pulmonary embolus (PE): Ischemic injury as a result of occlusion of pulmonary artery or branches, usually as a result of a DVT 3. Stroke (cerebrovascular accident, CVA): ischemic or hemorrhagic parenchymal injury as a result of arterial occlusion (atherosclerosis) or embolism. 4. Bowel infarction (ischemic bowel): variety of etiologies, often fatal in the elderly population. Nature of vascular supply - Some organs have dual blood supply - Collateral circulation may develop in some organs with slowly progressive narrowing of a vessel (coronary blood vessel angiogenic adaptation) Rate of development of the occlusion - Slowly developing occlusions may develop collateral circulation, in some organs atrophy may ensue - Acute or rapidly developing occlusions are more likely to cause infarction Vulnerability of the tissue - Neurons are the most sensitive to ischemia followed by the heart

Mathematical Formulation of Dose-Response Relationships

At equilibrium, the concentrations of D, R, and DR are: - Kd = (D)(R)/(DR) Fractional Occupancy = (DR)/(Rt) = (D) / Kd + (D) - fraction of receptors occupied depends only on concentration of drug and it's Kd value According to occupancy assumption, the magnitude of the biological response (effect), E, is proportional to the fraction of total receptor sites occupied by drug molecules, (DR)/(Rt), and the maximum response possible, Emax, is proportional to RT. Fraction of maximal response = E/Emax = (D) / Kd + (D) A plot of response versus drug concentration calculated by this equation gives a hyperbolic curve - response is expressed as a percent rather than a fraction of the maximum value - Emax - EC50: 50% occupancy, effective conc that stimulates 50% of the max response, when D = Kd half of R (receptors) is occupied - Note in 'simple system' the EC50 = Kd

Healing Response: Granulation Tissue

At high magnification, granulation tissue has: - capillaries (dilated, angiogenesis, leaky) - fibroblasts - variable amount of inflammatory cells (mostly mononuclear, but possibility of some PMN's)

Acute Inflammation: Vasculitis Higher Magnification

At higher magnification, vasculitis with arterial wall necrosis is seen Note the fragmented remains of neutrophilic nuclei (karyorrhexis) - Neutrophils breaking down Acute inflammation is a non-selective process that can lead to tissue destruction.

Neoplasia: Fibroadenoma Higher Magnification

At low power, fibroadenoma has compressed ducts surrounded by a fibrous stroma Lesions are most likely to be found as a "breast lump" on examination of young women They are discreet, firm, rubbery masses that are freely movable Benign lesion This will not develop into a cancer

Atrophy

Atrophy: - Decrease in size and number of cells and size of the organ - Note that this term is used to describe both events at the cellular level and the overall appearance of the organ based on weight - Atrophy can be either physiologic or pathologic - Physiologic atrophy is common during development Etiology 1. Decreased workload (disuse) 2. Denervation 3. Diminished blood supply (decreased nutrition, pressure associated with ischemia) 4. Diminished endocrine stimulation *Cellular changes: - Autophagic vacuoles - Lipofuscin granules Mechanisms: - Reduction in structural components - Increased protein degradation - Ubiquitin-proteasome pathway or lysosomal destruction Clinical correlation: Decreased workload/disuse atrophy (pathologic): - Typically refers to skeletal muscle atrophy - clinical example includes a broken bone that is immobilized - often a visible difference in size of the muscle in broken arm vs normal arm after cast removal Loss of innervation/denervation atrophy (pathologic): - Refers to skeletal muscle when nerve supply is cut or lost Diminished blood supply/ischemic atrophy (pathologic): - Any organ or tissue can atrophy secondary to a decreased blood supply - most common underlying mechanism is atherosclerosis (fat build-up and more) in the vessels that narrow the vascular lumen to that organ (or thickening in the muscular wall of arteries due to HTN narrows vascular lumen to organs - renal artery stenosis) Inadequate nutrition (pathologic): - Even if the blood supply gets to the organ, if there are deficient nutrients, the organ or tissue will also shrink - may be due to decreased intake or increased metabolism that can occur with cancer. Decreased hormonal stimulation (physiologic or pathologic): - As one ages, hormonal stimulation often decreases leading to a decrease in size and weight of the organ. Pressure/ischemia (pathologic): - Tissue compression can lead to atrophy. - Example: tumors that compress on adjacent tissues or structures may impede the blood supply to that area.

Phase I Reduction Reactions

Azo- and nitro-reductions are catalyzed by cytochrome P450

Role of B Lymphocytes and Plasma Cells

B CELLS GIVE RISE TO PLASMA CELLS THAT SECRETE ANTIBODIES When B cells exit the BM they can become one of the following types of cell: - plasma cell: secretes antibody - memory B cell: recalls previous encounter w/antigen - regulatory B cell

Cardiovascular Resuscitation in Septic Shock

Based on Emmanuel Rivers' "Early Goal Directed Therapy": - Early recognition and support initiated in the ED Protocol Driven: Goal directed regimen: - fluids - Vasopressors - Blood transfusions - Inotropic Agents In-hospital mortality decreased from 46.5% to 30.5% Now the current standard of t care

Binding of Agonists and Antagonists to Muscarinic Receptors

Based upon Nitrogen and Carbonyl Oxygen Sites - nitrogen (+ charge) binds to anionic binding site - carbonyl oxygen (- charge) binds to H-bonding site - 4.4A apart Agonist vs. Antagonists General Rule of pharmacology: simple drugs (structures) are usually agonists, big bulky molecules usually competitive antagonists MOST COMMON SIDE EFFECTS IS ANTIMUSCARNIC SIDE EFFECTS - only have to have to charge centers which binds to the anionic site and the H-bonding site 4.4 A apart - lots of drugs can fulfill this so many drug side effects are due to binding and antagonism of muscarinic receptors

Structural and Functional Differences in Immunoglobulin Isotypes

Basic structures of 5 Ig isotypes (or classes) differ - IgM and IgE lack hinge regions and have an extra domain (heavy chain constant domain) The 5 isotypes also differ in number and position of disulfide bonds and N-linked carbohydrates - structural differences lead to different functional properties of the isotypes. Two types of functions that an antibody performs: 1. effector functions 2. antigen recognition Effector functions of antibodies are a property of the heavy chain constant regions - effector functions of an antibody are dictated by class and subclass of the Ig (different heavy chain constant regions) - Effector functions relate to how the Ig interacts with other immune system components like complement and Fc receptors.

Neoplasia: Leiomyoma

Benign neoplasms can be multiple Uterus with leiomyomas of varying size As a general rule, benign neoplasms do not give rise to malignant neoplasms Oma = benign Leiomyo = Smooth muscle Pelvic pain, bleeding, can interfere with implanation if trying to get pregnant

Benign Tumors

Benign tumors are named by adding the suffix -oma to cell of origin Benign tumors are not capable of metastasis and are confined to the BM Examples: - Osteoma (benign tumor of bone) - Leiomyoma (benign tumor of smooth muscle) - Fibroma (benign tumor of fibrous tissue) - Adenoma (benign tumor of glandular epithelium) - Cystadenoma (benign tumor of glandular epithelium with a cystic component) Benign tumors generally: - resemble their normal histologic counterparts microscopically - encapsulated (not always) - are well circumscribed - are localized - are not life threatening - slower growth than malignant tumors Benign Neoplasms can: - produce hormones or other substances (pituitary adenomas) - cosmetic issues for patient (lipomas) - grow back after removal (constantly have to be resected) Depending on the exact location, even a benign tumor may be fatal: - in the brain (small space - could lead to hernation) - may be associated with a hemorrhage - may compress another vital structure Most benign tumors remain benign (they do not progress or transform to a malignant tumor)

Beta/Dopamine Receptor MOA and Alpha2 Receptor MOA Diagram

Binding to β adrenoceptors stimulates adenylyl cyclase by activating stimulatory G protein, Gs, which leads to the dissociation of α subunit charged with GTP - Activated αs subunit directly activates adenylyl cyclase resulting in an increased rate of synthesis of cAMP Alpha2-adrenoceptor ligands inhibit adenylyl cyclase by causing dissociation of inhibitory G protein, Gi, into its subunits --> activated αi subunit charged with GTP and a βγ unit. - Mechanism by which these subunits inhibit adenylyl cyclase is uncertain. cAMP binds to regulatory subunit (R) of cAMP-dependent protein kinase, leading to liberation of active catalytic subunits (C) that phosphorylate specific protein substrates and modify their activity - catalytic units also phosphorylate the cAMP response element binding protein (CREB), which modifies gene expression.

Comparison of Bioavailability of IV vs Oral Administration of a Drug

Bioavailability after administration of a single dose of drug. Intravenously administered drug: - immediately available in the circulation/blood (100% bioavailability) - drug is then distributed to other body compartments and eliminated by first-order kinetics (B-elimination) Other routes of administration (e.g., oral, subcutaneous, and intramuscular): - demonstrate slower entry of drug into the blood - nonintravenous routes of administration must take into account bioavailability - many orally administered drugs are incompletely absorbed or undergo first-pass metabolism in the liver If a drug has 100% bioavailability: - total amount of drug reaching systemic circulation will be the same for all routes of drug administration (same AUC) - nonintravenous routes will require a longer period of time to reach a peak concentration of drug in the plasma (different alpha-distribution phases) - same B-elimination rates (first order kinetics) - same drug metabolism/elimination once in circulation If the bioavailability of an oral, subcutaneous, or intramuscular dosage form is less than 100%: - dose of drug would have to be increased in order for total amount of drug reaching systemic circulation to be the same as that of an intravenous dose Total amount of drug reaching systemic circulation can be quantified by integrating the area under the curve (AUC) of the plasma drug concentration versus time plot Although different routes of administration (e.g., oral, subcutaneous, and intramuscular) can have different rates of drug absorption and therefore differ in the kinetics of plasma drug concentration over time (alpha distribution phases), if these routes exhibit the same level of bioavailability, then they will have the same AUC

Warfarin and Pharmacogenomics

Bleeding due to over-anticoagulation is risk of therapy with warfarin Non-Genetic Factors in Warfarin Pharmacokinetics and Response - Age - Weight - Dietary Vitamin K intake - Drug Interactions Genetic Factors in Warfarin PK and Response - VKORC1 (vitamin K epoxide reductase) reduces vitamin K 2,3-epoxide to active Vitamin K (important for coagulation cascade) --- Pharmacodynamic target of warfarin (inhibits VKORC1) --- Genetic variants in VKORC1 enzyme associated with decreased requirement for warfarin (less efficient enzyme, less warfarin needed) - CYP2C9 is responsible for metabolism of S-warfarin

Apoptosis

Defined: Programmed cell death Specific pathway whereby specific enzymes are activated to degrade the DNA and nucleus The cell fragments into apoptotic bodies composed of parts of cytoplasm and nucleus - apoptotic bodies are quickly removed without an inflammatory reaction/host reaction Can be physiologic or pathologic

Combined a1- and B-adrenergic Receptor Blockers

Block b-1, b-2 and a-1 adrenergic receptors - Blockade of b-adrenergic receptors causes decrease stimulation of heart by catecholamines - Blockade of a-receptors causes vasodilation (decreased TPR) - Any increase in sympathetic stimulation that might occur via the baroreceptor mechanism is attenuated because the a-1 and b-receptors are blocked - helps to make these drugs useful in the treatment of hypertension. 1. Carvedilol - Combined α1- and β blocker/receptor antagonist - for heart failure - Shown to decrease mortality and morbidity (days in hospital) in patients with moderate heart failure - α-1 receptors in heart may contribute to the enlargement of failing heart via a link to myokinase. Therefore, the α1 antagonist action may block this - This effect may also reflect "ligand bias" (activating one receptor-mediated pathway over another). - also has anti-oxidant and antiproliferative properties (may decrease cell enlargement in HF), which might contribute to its therapeutic effects 2. Labetalol - alpha and Beta-Adrenergic antagonist - Used primarily to treat hypertension in pregnancy - Used to treat hypertension during pregnancy and for hypertensive emergencies - Does not have the antiproliferative properties

Non-Selective Beta Blockers

Block both beta-1 and beta-2 receptors and beta-3 (in fat cells) 1. Propranolol - prototype - t1/2 = 3 - 6 h, but sustained release preparation is available - has large first-pass effect so individual variability in plasma concentration is high - has local anesthetic properties and high lipid solubility, thus some CNS effects 2. Nadolol - longer t1/2 = 14 - 24 h. 3. Timolol - used in eye for treatment of glaucoma **More than a dozen other beta-blockers on the market some with longer t1/2, some with more or less lipid solubility

Obstructive Shock

Blockage of flow out of heart resulting in decreased cardiac output Systemic vascular resistance increases to compensate Caused by: - pericardial tamponade - pulmonary embolism - tension pneumothorax

Hemodynamics: Ecchymoses

Blotchy areas of hemorrhage in the skin are called ecchymoses and areas of purpura - Ecchymoses are larger than petechiae - can appear with coagulation disorders Hemorrhage: Extravasation of blood outside a vessel (may be internal or external). Hematoma: Hemorrhage within a tissue with subsequent accumulation of blood. Petechiae: Minute hemorrhages (1-2 mm) often on skin surface, mucosal membranes and serosal surfaces. Purpura: Larger hemorrhages (> 3mm). Ecchymoses: Hemorrhages (>1-2 cm), often referred to as a subcutaneous hemorrhage.

Chronic Inflammation: Monocytes and Macrophages

Bone marrow stem cells give rise to monocytes. Monocytes circulate in the blood and then migrate into tissues where they differentiate into tissue macrophages. Process of monocyte extravasation is a highly regulated event mediated by certain adhesion molecules. Activation of tissue macrophages is also regulated by immune mediators, such as specific cytokines produced by T lymphocytes and NK cells as well as by non-immune mechanisms including bacterial endotoxins. Activated macrophages secrete mediators with a common goal of eliminating the injurious stimuli. Activated macrophages are larger, have increased lysosomal enzymes, more active metabolism and increased ability to kill the microbe. M1: - Classically, macrophages are activated by microbial products - macrophage produces substances that enhance removal of organism - Activation is mediated largely by IFN-gamma. M2: - Alternatively, macrophages can be activated by other cytokines (IL-4 and IL-13) - the macrophage functions to promote tissue repair.

Inclusions: Iron

Brown coarsely granular material in macrophages in this alveolus is hemosiderin that has accumulated as a result of the breakdown of RBC's and release of the iron in heme The macrophages clear up this debris, which is eventually recycled

Air Embolus

Bubbles caused by gas in circulation (in excess of 100cc) May cause obstruction and occlusion

Invasion

Cancers usually begin as localized growths, but may extend into adjacent tissues/structures (direct extension) Some tumors will: - have a capsule and a pushing borders -others will have irregular and poorly demarcated borders and infiltrate haphazardly. Some cancers as they invade will incite a fibroblastic reaction in surrounding tissue referred to as desmoplasia - gives tumor a very firm/hard consistency clinically and a scar-like appearance pathologically Ability of tumor cells to invade and metastasize depends on the expression of: - adhesion molecules - cytokines - proteolytic enzymes - growth factors

Cancer: Ability to Invade and Metastasize

Cadherins are downregulated in tumors, making cells less 'sticky' to each other Benign tumors show little type IV collagenase activity Malignant tumors overexpress type IV collagenase Tumors can use ameboid movements to get into vessels and lymphatics Invasion: Carcinoma Progression - insitu carcinoma (dysplasia) - microinvasion (penetrates BM) - local invasion (contiguous extension into organ) - local metastasis (discontiguous spread in organ/neighboring lymph nodes) - distant metastasis

Cardiac Hypertrophy

Cardiac hypertrophy involving the left ventricle The number of myocardial fibers does not increase, but their size can increase in response to an increased workload, leading to marked thickening of the left ventricle in this patient with systemic hypertension Hypertrophy: Adaptive response in which a cell becomes larger (increase in size) often due to increased workload. (normal numbers of cells just bigger, no change in cell number) - physiologic or pathologic

Acetylcholine Dose-Response Curve

Cardiovascular system --> activated by Muscarine Smooth muscle and glands --> activated by Muscarine ganglia, adrenal medulla --> activated by Nicotine NMJ --> activated by Nicotine

Fibrinolytic System

Cascading process mediated by plasmin (which is breakdown of inactive plasminogen) Plasminogen activators (PA): - Urokinase-like PA: present in plasma and other tissues - Tissue-type PA (t-PA): synthesized by endothelia, most active when attached to fibrin - Streptokinase: bacterial product Functions plasmin: Breaks down fibrin

Catecholamine Properties and Relative Receptor Potencies

Catecholamines: - catechol ring: little CNS access - metabolized by COMT in GI/liver - must give parenterally (iv, im, inhalation) as to not be degraded (first pass metabolism) a1 receptors - epi and norepi much more potent than isoproterenol - epi > norepi >>>> iso B2 receptors - isoproterenol and epi much more potent than norepi - iso > epi >>>>> norepi - essentially norepi does not act on B2 receptors B1 receptors - isoproterenol is more potent than epi and norepi - iso > epi = norpei

IgD Properties

Cecond antibody made by a B cell after IgM is IgD. Low levels in the serum Serum half life is very short Synthesis rate is extremely low when compared to IgG. Recent evidence suggest a role for IgD in protection from pathogens in the upper respiratory tract Other notable features of IgD are that: - it is a marker for mature B cells - fine-tunes B cell response to antigen After the B cell is activated by antigen, IgD is down-regulated

Irreversible Cell Injury

Cell cannot recover from the injurious stimulus. No clear-cut point Likely depends on the cellular environment, type and duration of injurious stimulus Irreversibly injured cells demonstrate the features of necrosis.

Apoptosis Morphology

Cell shrinkage (early, cytoplasm becomes 'dense') Chromatin condensation: - hallmark of apoptosis - pattern is specific: the chromatin aggregates peripherally within nucleus Cytoplasmic blebs: - Peripherally within the cytoplasm Apoptotic bodies: - remains after nuclear destruction/dissolution - Tightly packed organelles within the membrane. Phagocytosis: - Macrophages eat apoptotic bodies.

Cellular Response to Stress and Injury

Cells are dynamic to the stresses/external changes around them (within limits) Stress and the Cellular Response: - Homeostasis: steady state - Adaptation: Cellular change as a response to stress Cellular adaptations Mechanisms of cell injury Mechanisms of cell death: - Necrosis - Apoptosis Intracellular accumulations Tissue calcification

Cerebral Atrophy

Cerebral atrophy in a patient with Alzheimer's disease Gyri are narrowed and sulci widened toward to frontal pole Atrophy: Adaptive response in which a cell becomes smaller (decrease in size) secondary to: - decreased workload - denervation - decreased blood supply - decreased endocrine stimulation

Chronic Inflammation: Lung

Certain etiologic agents such as viruses are more likely to lead to chronic inflammation, as seen here in the lung of a patient with influenza A Chronic inflammation of the lung - viral infection of the alveolar wall (no productive cough) - inflammatory cells are not in the alveolar space, in the surrounding tissue (interstitial space) Note: inflammatory infiltrates of chronic inflammation are more likely to be interstitial (within tissues) rather than exudative (above surfaces or in spaces) like acute inflammation Hallmark cells - lymphocytes, macrophages Tissue response hallmark - fibrosis: deposition of collagen Chronic inflammation: - Long duration and involves lymphocytes and macrophages primarily - 'Granulomatous' inflammation is a type of chronic inflammatory reaction

Infection Triggers an Inflammatory Response

Chemokines and cytokines released from DC and MO act on capillaries in vicinity of pathogen to recruit more phagocytes from the blood, predominantly the PMN (neutrophil) Under influence of cytokines and pharmacologically active mediators (from mast cells): - vasodilation of capillaries: blood vessel dilates slowing down blood flow so that immune/effector cells in the blood start to roll along the wall of the vessel and are captured by cell adhesion molecules (expressed by activated endothelium cells) - cells in blood squeeze between the endothelial cells of the blood vessel and are attracted to the site of infection by a chemokine gradient (chemotaxis) - Plasma proteins also escape into the tissues bringing antibodies and various antimicrobial factors, complement, etc. Downstream the vessel clots to prevent the pathogen entering the circulation.

Acetylcholine Synapse

Choline taken up into nerve terminal Choline + Acetyl CoA from TCA = Acetylcholine by enzyme Choline acetyltransferase (ChAT) ACh actively transported into vesicles Ca2+ dependent release into synaptic cleft Binds to ACh receptors (nicotinic or muscarinic) on post synaptic cell Degraded into choline and Acetyl CoA by Acetylcholinesterase anchored to postsynaptic cell membrane

Chronic Inflammation: Synovium

Chronic inflammation can go on for a long time - Longer duration - insidious onset, weeks, month, lifetime - Caused by Persistent infections (viral, parasite) - Autoimmune diseases also: leads to ongoing inflammation in the tissues Seen here in the synovium of a patient with rheumatoid arthritis are collections of dark blue lymphocytes - lymphoid aggregates

Neoplasia: Renal Cell Carcinoma Higher Magnifcation

Classic histologic appearance of a renal cell carcinoma: neoplastic cells have clear cytoplasm and are arranged in nests with intervening blood vessels. This appearance is why they are often called "clear cell carcinomas".

Elucidation of Immunoglobulin Structure

Cleavage of an antibody with papain - occurs in hinge region above the disulfide bonds - generates two different types of fragments termed Fab and Fc Each Ig monomer has two Fab fragments and these fragments were found to possess the antigen binding properties The Fc fragment was found to crystallize and to bind to receptors (called Fc receptors) on cell surfaces. Cleavage of an antibody with pepsin - occurs below S-S bonds of the hinge region as well as at multiple spots in the CH2 domain - yields a fragment termed F(ab')2: made up of 2 Fab fragments held together by the disulfide bonds in the hinge region - yields partial Fc fragment generated. Recombinant DNA technology has also generated a HC V region linked to a LC V region an Ig fragment called a single chain Fv which is also used in immunotherapy.

Clonal Selection

Clonal selection hypothesis - describes how huge repertoire of B cells and T cells each with a unique receptor are generated in the bone marrow and thymus, respectively Both B cells and T cells originate from the common lymphoid progenitor Both early B cells and early T cells have multiple gene segments that are randomly joined to form: - functional variable domain of heavy and light chains of the BCR - functional variable domain of α and β chains of TCR Random gene rearrangement to form the variable regions may result in a receptor that recognizes self antigens - any cells displaying self-reactive receptors are eliminated in bone marrow and thymus Naïve B cells and T cells leaving the bone marrow and thymus should only recognize foreign (non-self) antigens Both naïve B cells and T cells travel to secondary lymphoid tissue T cell enters the paracortex of a secondary lymphoid organ and looks for a DC displaying peptide (held in an MHC molecule) for which the TCR is specific (for the peptide and MHC) - interaction is first step in T cell activation B cell enters the outer cortex of a lymph node and becomes part of an aggregation of B cells called a B cell follicle - searches for antigens coming into the lymph node for which its BCR is specific - B cell may bind the antigen directly or pluck antigen from a subcortical macrophage or a follicular dendritic cell (concentrate antigens on their surface) - Interaction with antigen causes the B cell to search for a T cell to help it make antibody

Patterns of Necrosis

Coagulative necrosis Liquefactive necrosis Caseous necrosis Fat necrosis Fibrinoid necrosis

Reuptake Blockers

Cocaine Desipramine

Pharmacological Antagonists

Competitive Inhibition Noncompetitive Inhibition Agonist and antagonist both work on the SAME RECEPTOR

Outcomes of Acute Inflammation

Complete resolution: - inflammatory process is complete - cessation of leukocyte infiltration - return of normal vascular permeability and normal tissue Healing by fibrosis: - With more extensive inflammation and tissue necrosis - connective tissue replacement occurs (scar) Progression to chronic process: - no exact measurements or criteria to say why some acute inflammatory reactions become chronic problems - Often stimulus is not removed adequately or there is some block or interference with normal acute reaction/resolution - Many chronic inflammatory processes begin as a chronic problem and do not necessarily arise secondary to an acute inflammation.

Inflammation General Features

Complex reaction to an injurious agent (microbes/damaged cells) Involves chemical mediators, vascular and cellular events that lead to accumulation of fluid and WBCs in the injured area Broadly separate inflammation into an acute process or a chronic process - based on onset, duration, stimulus, types of cells/morphologic pattern 5 Rs of Inflammation 1. Recognition of injurious agent 2. Recruitment of leukocytes 3. Removal of agent 4. Regulation of response 5. Resolution/repair of any damaged tissue itis - vasculitis - gastritis - meningitis

Primary vs. Secondary Immune Réponse

Concept of immunological memory - mediated by memory B cells and memory T cells. Memory cell are the fittest B and T cells that were activated during the initial encounter with the pathogen. After the pathogen is eliminated almost all B and T cells undergo apoptosis leaving behind a small number of B and T memory cells. Consider immunizing a naïve animal with antigen A - animal has never seen antigen A before - lag phase in the antibody response to antigen reflects time from when the antigen is picked up by DCs that travel to secondary lymphoid tissues to present peptides to naïve T cells - antigen A-specific naïve T cells have to expand in population and some have to become follicular helper T cells which move to the junction between the paracortex and the B cell follicles - at the same time naïve B cells in the follicles pick up antigen A directly, or from follicular dendritic cells or subcortical macrophages - Antigen A-specific B cells travel to meet follicular helper T cells at the follicle-paracortical junction and both enter the B cell follicle where B cells are instructed to make high affinity antibody to antigen A - Early IgM antibodies come from B cells that have trafficked directly from the B cell follicle to the lymph node medulla - As antibody is secreted by plasma cells, first IgM and then IgG appear in the blood - amount of antibody increases until the antigen is cleared after which the B cells contract leaving behind memory B cells If after a few months the same animal is injected again with antigen A - memory B cells and T cells are immediately activated and antibody appears in the blood almost immediately - more antibody is made, it is exclusively IgG and it has higher affinity for antigen A If another antigen is injected (antigen B) at the same time as the second dose of antigen A, the response to antigen is a primary response with the same kinetics as that to the first dose of antigen A.

Phase II Reactions

Conjugation Reactions: Drug or metabolite conjugated with endogenous substrate - glucuronic acid - acetic acid - sulfuric acid - glutathione - methylation Enzymes occur primarily in cytosol - except UDP-glucuronyl transferase (microsomal) Types of Phase II Reactions: - Table

Immune System as a Surveillance System

Constant patrols the human body looking for altered self (cancer) and dangerous non-self (pathogens) What is altered self? mutated cells What is non-self? Anything that isn't self, Non-self can be of 2 types: - Harmless: food, pollen, dander - Dangerous: pathogens The immune system must eliminate dangerous non-self and altered self, and ignore harmless non-self. Goal of immune system: maintain homeostasis by identifying and eliminating anything that endangers you - external threat i.e., an infectious agent - one of your cells that undergoes malignant transformation The immune system must avoid being activated by harmless antigens - activation of immune system causes host cell damage Cells that recognize non-self are termed sentinel cells - epithelium, DC, macrophages, NK cell.

Epinephrine Reversal

Conversion of increase in BP (pressor response) in response to a high dose of epinephrine to a decrease in BP after blocking α-adrenergic receptors (e.g. with phentolamine) - revealing vasodilating effects mediated by β2 adrenergic receptors Tracings show the response to a high dose of epinephrine before and after phentolamine, a drug that blocks epinephrine action at receptors that mediate vasoconstriction (the α-adrenergic receptors). A dose of epinephrine that has a pressor effect before phentolamine has a depressor effect after phentolamine This is important historically because it indicated the likely existence of different types of epinephrine receptors relevant to physiology, including cardiovascular function. These are classified as α- and β-adrenergic receptors. We now know there are 10 adrenergic receptors in adult humans. Graph: 1. Phentolamine (a-adrenergic antagonist) --> lowers BP (decrease vascular tone) 2. Epi --> increases BP (a1, a2B effects) 3. Phentolamine w/Epi --> lowers BP even more than phentolamine alone, suggests that when alpha effects of Epi are blocked, Epi effects other adrenergic receptors that cause vasodilation --> decrease in TPR Clinical concern: - α-adrenergic receptors may be blocked by some drugs as a side effect (e.g., antihistamines, some antidepressants and some antipsychotics)

Hemodynamics: Coronary Thrombosis

Coronary thrombosis One of the complications of atherosclerosis Left: Dark red thrombus is seen in the anterior descending coronary artery Right: Coronary thrombosis at higher magnification Thrombus occludes the lumen and produces ischemia and/or infarction of the myocardium

Hemodynamics: Coronary Thrombosis Higher Magnification

Coronary thrombus is seen microscopically occluding the remaining small lumen of this coronary artery.

Neoplasia: Lymphoma

Cross section through the mesentery to reveal multiple enlarged lymph nodes that abut each other. Unlike metastases, nodes with lymphoma tend to have little necrosis and maintain a solid, fleshy tan appearance.

Metabolic Resuscitation in Septic Shock

Current Controversy Marik Cocktail: 2017 Vitamin C levels fall during sepsis: - Deficiency leads to endothelial boundary disruption (leading to edema seen in scurvy) - Required for synthesis of catecholamines --> failure of SNS Thiamine Deficiency is common in sepsis (approx 1/3) - associated with increased mortality - Beriberi mimics sepsis by causing distributive shock and lactic acidosis Glucocorticoids - increase expression of sodium-vitamin C transporter. - Endothelial integrity was preserved in combination w vit C but not when either evaluated alone Mortality: 8.5% vs. 40.4% (p<0.001) Vasopressors weaned off earlier with less volume needed Severity of illness scores improved across the board Currently be tested

Paraneoplastic Syndromes: 1. Endocrinopathies

Cushing's Syndrome: - Ectopic production of ACTH (adrenocorticotropic hormone): stimulates adrenal cortex hormones, Na+ retention - hypertension, muscle wasting, hypokalemia, dark skin striae Common Causes: - Small cell lung cancer - pancreatic neuroendocrine tumors Paraneoplastic Hypercalcemia: - Release of parathyroid hormone related peptide (PTHrp) by tumor - mobilizes calcium from bones to the blood (activates osteoclasts) Common Causes: - Squamous cell carcinomas of lung - breast carcinoma Syndrome of Inappropriate ADH secretion (SIADH): - Ectopic production of ADH: hypo-osmolar hyponatremia (water retention) Common cause: Small cell lung cancer

Neoplasia: Hepatic Adenoma

Cut surface of the liver reveals hepatic adenoma Note how well circumscribed it is. Benign tumor in the liver - Anabolic Steroids - Well circumscribed - Not infiltrating into the liver

Phase I Microsomal Oxidative Drug Metabolism

Cytochrome P450 Hepatic Microsomal Oxidation Mixed Function Oxidase (MFO) System Hepatic smooth ER: primary source of cytochrome P450 system. - Microsomes are fragments of ER that are obtained in vitro by physical disruption of the tissue and differential centrifugation. Extrahepatic sites of P450-mediated reactions: - include lung, kidney, skin, and intestinal mucosa Other drug metabolizing enzymes in microsomes include flavin mono-oxygenase (FMO3) Types of P450-mediated (microsomal) oxidation reactions - IMAGE - Expoxidation - look out for toxic metabolite production Cytochrome P450 Isozymes - clinically relevant in drug metabolism - CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP2E1, CYP3A - Small differences in amino acid sequence can have important consequences in drug metabolism - CYP2B6, CYP2C19, CYP2C9, and CYP2D6 show genetic variability in expression - Inhibited by commonly used drugs - All except CYP2D6 can be induced (inducible)

Inclusions: Intermediate Filaments

Cytoplasmic organelle damage leads to a variety of injury patterns, most of which are best seen by electron microscopy - Acute injuries tend to damage an entire cell, so specific organelle damage is beside the point. - However, in some cases the damage can be cumulative over many years Here are Mallory bodies (the red globular material) composed of cytoskeletal filaments in liver cells chronically damaged from alcoholism - These are a type of "intermediate" filament between the size of actin (thin) and myosin (thick) Abnormal accumulation of keratin of cytoskeleton of hepatocytes due to alcoholic hepatistis

Embolism

Detached intravascular solid, liquid or gaseous mass that is carried by blood to a site distant from the point of origin

Hypovolemic Shock

Decreased blood flow to heart because of volume loss - loss of total blood volume (bleeding) or - loss of plasma (burn) Systemic vascular resistance (TPR) increases to compensate for reduced CO to maintain perfusion to vital organs

The Dendritic Cell

DCs exist in two states 1. When they are resting (not responding to danger) they are regulatory cells that produce cytokines that prevent the activation of T lymphocytes (IL-10, TGF-B) - display few receptors at low levels - in this state they prevent the immune system from responding to harmless non-self such as food. 2. When DCs encounter dangerous non-self they become phagocytic and take up pathogens and kill and dismantle them. - Once DC PRRs ligate MAMPs --> signal transduction pathways are activated to cause increased expression of various molecules on the membrane of the DC - MHC class I and II - costimulatory molecules B7.1 and B7.2 - several cell adhesion molecules (CD11c, ICAM-1, CD58, LFA-1< ICAM-2) - chemokine receptor CCR7 - secrete interleukin1 (IL-1) and cytokine CCL18 Expression of chemokine receptor CCR7 allows homing of DCs to lymph nodes because CCR7 recognizes cytokines produced constitutively by lymph nodes. Activated DCs are termed licensed or mature. - Mature conventional dendritic cells (DC) are primarily concerned with activation of naive T cells - several subsets of conventional dendritic cells - process antigen efficiently (exception: plasmacytoid DC) - when mature they express MHC proteins and co-stimulatory molecules for priming naive T cells Immature dendritic cells lack many of the cell-surface molecules listed but have numerous surface receptors (PRRs) that recognize pathogen molecules (MAMPs), including most of the Toll-like receptors (TLRs) DCs are unique among antigen-presenting cells (APCs) because they are the only cells that can activate a naïve T cell. DCs can tell the class of pathogen and it origin (either outside or inside the cell) due to: - different PRRs recognize different MAMPs that are characteristic of different classes of pathogen AND - because PRRs bind MAMPs located on the cell membrane, in endosomes/phagosomes and the cytosol When DCs present peptide in the context of MHC molecules to naïve T cells in paracortex of lymph nodes - drive naïve T cells to become a particular subset that is appropriate to deal with the type of pathogen encountered by the DC - accomplished by the DC secreting different cytokines that are able to polarize the naïve T cell.

Bridge Between the Innate and Adaptive Immune Response: Dendritic Cells

DCs express a full complement of signaling pattern recognition receptors (PRRs) that allow it to determine the type of pathogen and its source (extracellular or intracellular) The signaling PPRs (mainly TLRs) are located on the membrane, phagosomes/endosomes, and cytosol of the DC When the DC binds MAMPs it stops acting as a phagocyte and becomes a dedicated antigen presenting cell (APC) - leaves the barrier epithelial to travel to the paracortex of the closest lymph node via the lymphatics - paracortex is the region where naïve T cells congregate after they leave the thymus. DC IS THE ONLY CELL THAT CAN ACTIVATE A NAÏVE T CELL

DC Antigen Presentation to Naive T-cells

DCs present fragments of antigens held in MHC molecules to naive T cells - DCs meet the native T cells in the paracortex of SECONDARY LYMPHOID ORANS Epitope: amino acid sequence recognized by T-cell receptors (TCR) and B-cell receptors (BCR) - Epitopes are 8-18 amino acids in length Only way a T cell can see an epitope is if it presented to it by a major histocompatibility complex (MHC) molecule - MHC as a hot dog bun and - peptide as a hot dog T cell recognizes both the peptide and the MHC molecule APCs have to present peptides (epitopes) derived from pathogens they have digested and place them in MHC molecules which then traffic to the membrane of the APC - epitopes recognized by TCRs often come from hydrophobic regions of the folded protein

Cancer: Evasion of Apoptosis

DNA damage, loss of adhesion to basement membrane and other cell signals can trigger apoptosis. Cells adapt to evade apoptosis at nearly every point in the cascade. Over-expression of BCL-2 - seen in many lymphomas - causes less apoptosis and thus cells accumulate, rather than proliferate - cancer is thus more indolent - not a proliferating process just evading death so slower progression of cancer!

Hemorrhage

Defined as extravasation of blood outside of the vessel Many types of hemorrhages in various or any part of the body Often a result of vascular injury Clinical manifestations are dependent on: - size of the vessel - location of the vessel - duration and extent of injury

Light and Heavy Chain Gene Rearrangement

DNA rearrangement occurs during B cell development to produce a functional HC gene and LC gene - As a hematopoietic stem cell differentiates into a B lymphocyte in the BM, the DNA within the HC and LC loci breaks and rejoins (i.e., rearranges) to form a functional (or expressed) HC and LC gene - rearrangement of HC locus occurs before LC locus rearranges HC gene rearrangement: - one of the D segments is randomly spliced next to one of the J segments - V segment along with its corresponding leader sequence segment is spliced next to the rearranged D-J LC gene rearrangement: - In each B cell, at random, the LC locus DNA is broken and rejoined so that one of the multiple V gene segments is spliced next to one of the 5 J segments - Different B cells rearrange different V and J segments DNA sequences downstream of each V exon and upstream of each J exon ensure that the splicing takes place at the correct position HC locus organization is similar to LC locus organization with a few exceptions: 1. V region of the heavy chain is specified by 3 exons, V, D (diversity), and J, instead of 2 exons, V and J, as in the light chain gene 2. constant region is divided into several exons, each specifying one of the constant region domains (CH1, CH2, etc) and one specifying the hinge region 3. There are additional heavy chain constant region exons that determine whether the antibody will be membrane-bound (on B cell surface) or secreted 4. choice of which exons are used is determined during mRNA processing and alters from membrane-bound as the B cell starts secreting antibody and develops into a plasma cell. Gene rearrangement is facilitated by a variety of enzymes: - encoded by RAG genes (recombination activating genes) - Mutations in RAG genes lead to forms of severe combined immunodeficiency (SCID; Omenn's Syndrome) and failure to effectively synthesize antibodies. Rearrangement of the DNA permanently alters the locus since genetic material is lost in the rearrangement Rearrangement is somatic - it occurs during B cell development and is not passed on to offspring When light and heavy chain loci are rearranged, the B cell produces IgM antibodies. Summary: - Ig loci rearrange as the hematopoietic stem cell matures to a B cell - permanent DNA rearrangements involving V, D, and J segments in the heavy chain locus and V and J segments in the light chain locus - process of determining which segments are spliced together is random in each B cell and is called combinatorial diversity.

Components of a Perscription

Date Name/DOB Address Age -adult or weight of child and dose in mg/Kg/day Rx "recipe" - Four Requirements for each drug that is prescribed 1. Medication Name (Brand vs Generic) 2. Strength (milligrams, grains, units) 3. Formula (tablets, capsules, liquids, cream) 4. Quantity (Amount Dispensed) Examples: - Imodium 2 mg caps #20 - Diazepam 2 mg tab #20 Signatura (sig) - Directions for patient - always write in english Examples: 1 tab qid, ac + hs - qd bid tid qid, qod - ac pc hs q6h Refill Information Signature, Name, Address, Registry Number of Physician Safety Closure Container Liquids 1 teaspoon = 5 ml 1 tablespoon = 15 ml 1 oz = 30 ml Rx Pen VK 250 mg / 5 ml Sig: 1 tsp qid, ac + hs (for 10 full days) Disp: how many ounces?

Neoplasia

Definition: - new, uncontrolled growth - resulting growth referred to as a neoplasm - Tumor is used interchangeably with neoplasm - A tumor or neoplasm is a general term and does not indicate that it is benign (not capable of invasion and metastases) or malignant (capable of invasion and metastases) Neoplasms are monoclonal (originate from single transformed cell) and grow autonomously (absence of inducing agent) - non-neoplastic cell proliferation is typically polyclonal Terms benign and malignant refer to overall biological behavior of a tumor rather than to its morphologic characteristics All tumors have: - parenchymal component (tumor cell) - stromal component (reactive connective tissue, blood vessels, immune cells) Nomenclature is dependent on parenchymal component Growth and spread is dependent on the stroma The exact stimulus or etiology for a given neoplasm may not be identifiable; with most neoplasms (benign and malignant), the cause is unknown.

Epigenetics

Definition: Changes in gene expression caused by DNA modifications that occur without changes in DNA sequence (changes in phenotype w/o changing genotype) - DNA methylation - Histone modifications: determine whether DNA can be transcribed - RNA: can turn genes off by triggering DNA methylation or histone modifications May be a reason why genotype does not always predict phenotype - estimated that only 20-30% of variability in drug response (safety or efficacy) is explained by genetic factors Some epigenetic changes are associated with disease - Cancers: some treatments are designed to target the epigenome - Some forms of mental retardation - Some autoimmune disease - Some neuropsychiatric disease, Mood disorders, Alzheimer's disease, Autism

Prescription Writing

Definition: an order for medication written as a formula for a particular individual at a specific time

Amyloidosis: Diagnosis and Biopsy

Diagnosis of amyloidosis depends on tissue demonstration of amyloid deposits. Most common sites of tissue biopsy: - Rectum - Gingival tissues - Subcutaneous abdominal tissue Special stain: Congo red Other techniques and protein typing: a. Serum/urine electrophoresis (AL associated) b. Bone marrow biopsy to demonstrate a plasmacytosis (AL associated) c. Scintigraphy with radiolabeled SAP d. Immunohistochemistry

Hemodynamics: Subarachnoid Hemorrhage

Diffuse subarachnoid hemorrhage Extends from the base of the brain to the lateral surface of frontal and temporal lobes **Note that there is no blood beneath the dura reflected upwards (not a subdural hemorrhage)

Paraneoplastic Syndromes: 3. Hyper coagulability

Disseminated Intravascular Coagulation (DIC) - Systemic activation of coagulation consumes factors and platelets - produce bleeding, vascular occlusion and tissue hypoxia Common Causes: acute leukemia, prostatic adenocarcinoma Migratory Thromboplebitis (Trousseau Syndrome) - Tumors produce procoagulant factors - can lead to the vein thrombosis (DVT) or pulmonary embolism in one site, resolution, and then forming at another site Common Causes: deep seeded cancers (pancreas, lung)

Hemodynamics: DIC

Disseminated intravascular coagulation (DIC): - Abnormal systemic activation of thrombosis and fibrinolytic systems leading to a consumptive coagulopathy - Occurs as a secondary event in patients with another, often serious medical problem (obstetrical emergencies, severe burns (endothelial damage), advanced malignancies). Left: Disseminated intravascular coagulation (DIC) is a consequence of widespread activation of the coagulation system through endothelial injury and/or release of thromboplastic substances into the circulation - DIC can be seen with severe infections, trauma, neoplasia, and obstetric complications, among others. - Small fibrin thrombi can form in small arteries of brain, heart lungs, kidneys, and other organs to produce ischemic tissue damage. Right: Small fibrin thrombi from widespread activation of the coagulation system with disseminated intravascular coagulopathy (DIC) can be seen in capillary loops in this glomerulus, highlighted by a fibrin stain. Laboratory findings with DIC include: - decreased platelets - diminished fibrinogen - prolonged prothrombin time - elevated partial thromboplastin time - elevated D-dimer Consumption of coagulation factors w/generation of fibrin split products, along with platelet consumption, leads to these findings.

Beta agonists

Dobutamine (beta1) Albuterol (beta2)

Storage of Catecholamines

Dopamine is synthesized in the cytoplasm Dopamine is actively transported into vesicles by vesicular monoamine transporter (VMAT) - active transport mechanism is used by various transmitters (DA, NE, EPI, 5-HT) and is inhibited by drugs such as reserpine. Dopamine is converted to norepinephrine by DBH in the vesicles

Excretion

Drug and/or its metabolites are excreted via: - kidneys - stool - breath - sweat. Concentration of the drug in the blood changes with time because of absorption, distribution, metabolism and excretion

Muscarinic and Nicotinic Potentiators

Drugs that Enhance the Effects of Acetylcholine at Both Muscarinic and Nicotinic Receptors Acetylcholinesterase Inhibitors (AChE inhibitors) - derivates of carbamic acid - COONH2 - inhibits the breakdown of ACh at the synapse leading to an increase/build up of ACh in the synapse enhancing its effects Acetyl derivative bound to AChE creates steric hindrance b/c of nitrogen and it takes a longer time for the water molecule to break the bond with the AChE enzyme - 30 minutes vs. milliseconds Lead to build up AChE levels centrally (CNS) at the synapse - used to treat Alzheimers where we get a degradation of cholinergic neurons in the CNS (brain) - improve quality of life, cannot reverse cholinergic neuron degradation Reverse affects of curare (build up Ach levels in the body) - want to give an antimuscarinic at the same time (only interested in the effects of the AChE inhibitor at the NMJ not at all the other sites in the body) Second Group Edrophonium - short acting, N binds to anionic site - can reverse effects of curare Third Group Organophosphates - would need 60 days of hydration to break the bound - long acting AChE inhibitor - can be longer term treatment for glacoma - insecticides - build up of ACh to toxic levels - not conducive to life - led to development of chemical warfare agents which are just super toxic insecticides, also organophosphates ACh synapse on fire if exposure to these organophosphate warfare agents

Partial Agonists

Drugs that occupy receptors but bring about less than the maximum response - these drugs are less powerful - 100% occupancy produces a lesser response (correspond to substrates with a lower Vmax in enzyme analogy) - have lower efficacy Partial Agonists 2. If D has high affinity (Kd=1 nM) for R* and modest affinity (Kd=10 nM) for R

Calcifications

Dystrophic or Metastatic This is dystrophic calcification in the wall of the stomach - At the far left is an artery with calcification in its wall - There are also irregular bluish-purple deposits of calcium in the submucosa - Calcium is more likely to be deposited in tissues that are damaged.

Efficacy vs. Potency

Efficacy: - indicate ability of drug to produce a response - power - intrinsic activity - corresponds to Vmax - where is the curve on the y-axis? Potency: - indicate ability of drug to bind to receptor - affinity - Kd, EC50, ED50 - corresponds to Km - Where is the curve on the x-axis? Two drugs that have the same efficacy but different potency - same Emax, but different EC50 (binding affinity to receptor)

Role of the Adrenal Medulla and Epinephrine

EPI released by adrenal medulla enhances the effects of locally released NE on alpha and beta1 receptors Because EPI it also stimulates beta2 receptors, circulating EPI produces bronchodilation, glycogen breakdown and vasodilation of blood vessels in skeletal muscles and liver - vasodilation results in shunting of blood from other tissues such as skin to skeletal muscles In addition to stimulating receptors that are innervated by SNS neurons, circulating EPI also stimulates receptors that are not innervated by SNS neurons.

Division on Immunoglobulin into Variable and Constant Regions

Each polypeptide in an Ig monomer is divided into two sections - variable region (shown in red) - constant region (shown in blue) In an intact Ig monomer: - variable regions bind antigen - constant regions bind complement and cellular receptors Variable regions of light and heavy chains are located at amino-terminal end of the polypeptide chains and are each ~110 amino acids long - Termed variable regions because they vary extensively in aa sequence (specifically at HVRs vs framework regions) among antibodies with different antigen-binding specificities The a sequence of the carboxy-terminal portions of the LC and HC are shared by many antibodies and are called constant regions.

Amyloidosis: Treatment

Early diagnosis is important. Important to act quickly before permanent organ damage occurs. In many cases, if the underlying disorder is treated, one usually sees improvement of target organs. Clonal disorders of plasma cells are treated with chemotherapy and or bone marrow transplantation. Inflammatory disorders associated with reactive type amyloidosis are treated with anti-inflammatory drugs. Liver transplantation has been used to treat some types in which mutant protein is produced in the liver; however this is far from optimal. Newer Therapies: - Aimed at correcting unstable protein and abnormal folding - Determining and identifying any key proteases that may play a role. - Intervention of amyloid deposits. - Immunotherapy.

Management of Sepsis

Elements of Cares: 1. Resuscitation --> Fluids/Vasopressors 2. Infection Control 3. Respiratory Support - lower tidal volumes better outcomes 4. CNS support - start physical/occupational therapy early - better outcomes 5. General Supportive Care

Zero Order Kinetics

Elimination of a few drugs (e.g. ethanol, phenytoin, and aspirin at higher doses) do not follow first order kinetics Enzymes are overwhelmed (saturated) by large doses - drug concentration > Km for metabolic enzyme - the elimination system can only work at Vmax and a fixed amount of drug is eliminated at a constant rate (mg/min) - The concept of half-life does not apply to zero-order kinetics.

Physiologic Apoptosis Etiology

Embryogenesis: - Much of the developing fetus involves apoptosis. Hormone-related involution: - Breast after lactation is complete and endometrium during a cycle. Epithelial maintenance: - Most epithelial tissues undergo apoptosis in order to maintain an appropriate number of cells (skin and GI tract) Inflammatory cells: - elimination of potentially harmful lymphocytes as recognized by self Cytotoxic T cells induce virally infected cells

Intracellular Sites of Drug Metabolizing Enzymes

Endoplasmic Reticulum Mitochondria Cytosol Lysosomes Nuclear Envelope Plasma Membrane

Hemostasis: Endothelium

Endothelium plays a major role in hemostasis Activators and injurious agents that turn on endothelium: - Hemodynamic factors - Infectious agents - Plasma mediators - Cytokines Antithrombotic Properties Antiplatelet factors: - An intact endothelial prevents subendothelial EMC from coming into contact with platelets - Prostacyclin: produced by endothelium, vasodilator, inhibitor of platelet aggregation - Nitric oxide: produced by endothelium, inhibits platelet aggregation - Adenosine diphosphatase: expressed on endothelial cells, degrades ADP and inhibits platelet aggregation Anticoagulant effects: - Heparin-like molecules: cofactors of antithrombin III (which inactivates thrombin and other factors) - Thrombomodulin: binds to thrombin and becomes activated then in turn activates protein C. 1. Protein C: with the help of protein S, cleaves factors Va and VIIIa 2. Protein S: Produced by endothelium, acts as a co-factor for protein C - Tissue factor pathway inhibitor: on surface of endothelium, inhibits activated tissue factor Fibrinolytic effects: - Tissue-type plasminogen activator (t-PA): produced by endothelium, helps to clear fibrin Prothrombotic Properties Platelet effects - Von Willebrand factor (vWF): produced by endothelium, enhances platelet adhesion to endothelium Procoagulant effects - Tissue factor: stimulated by bacterial endotoxins or cytokines, activates extrinsic clotting cascade Antifibrinolytic effects - Plasminogen activator inhibitors: produced by endothelia and suppress fibrinolysis

Catecholamines

Epinephrine Norepinephrine Isoproterenol Dopamine Dobutamine

Phase I Hydrolysis Reactions

Esterases - plasma, liver, and other tissues Amidases - liver and gut flora

Causes of Cell Injury

Etiology of Cell Injury Hypoxia/Ischemia: Oxygen deficiency Physical agents: Trauma, temperature changes, radiation, electrical injury. Chemical agents: Organic (glucose and salt), poisons, insecticides, drugs Infectious: Many infections can directly damage the cell or cause damage secondary to the inflammatory reaction that they incite. Immunologic: Autoimmunity and other forms hypersensitivity reactions Genetics: There are many genetic mutations that lead to disease and cellular injury Nutritional: Both too little and too much can be a problem. - B12 and/or folate deficiencies can lead to anemia - too much cholesterol/lipid leads to blockage of blood vessels via atherosclerosis

Neoplasia: Liver Metasteses

Example of extensive metastases to the liver A primary neoplasm of the liver is more likely to be a solitary mass The presence of metastases is the best indication that a neoplasm is malignant Systemic effects of having a malignancy (weak, tired, cachexia, loss of appetite, weight loss) Rapid growth impinging on other structures may cause pain Metatases from other organ Not a cancer originating in the liver, orginating from other organ Colon cancer frequently goes to the liver Can spread locally if breaks thorugh BM Can then go into lymphatics and spread Hematogenous spread: liver, lung (multiple nodules in these structures might indicate metastatic cancer) rather than just a singular nodule

Acute Inflammation: Fibrin Mesh

Example of the fibrin mesh in fluid with PMN's that has formed in the area of acute inflammation - Pink material is protein (fibrin) - end product of coagulation It is this fluid collection that produces the "tumor" or swelling aspect of acute inflammation

Beta-Adrenergic Receptor Antagonists: Therapeutic Uses

Exercise-induced angina (cardiac ischemia due to poor perfusion of coronary vessels/insufficient coronary) - decrease cardiac work leads to a decrease in oxygen demand and improved cardiac exercise tolerance - Decreased renin release also decreases heart O2 demands - But, beta-blockers can decrease skeletal muscle exercise tolerance by blocking fat cell release of free fatty acids, which are used by exercising muscle. (Beta 3 receptor on fat cell?) Suppression of cardiac arrhythmias (leading cause of death) - decreased incidence of ventricular ectopic beats - decrease conduction in SA and AV node - stabilize heart rhythm Post-myocardial infarction - Increase survival after MI - Probably by protecting against post-MI ventricular fibrillation episodes - Beta-blockers after an MI have been shown to prolong survival after acute MI - Current data suggests that if the heart rhythm/cardiovascular state is stable, beta blocker can be stopped after 3-4 years. - But non-select beta-blockers can also worsen lipid profile. How? Decrease in HDL and HDL/LDL ratio Chronic Congestive Heart Failure - This probably seems counterintuitive (and it should), but beta-blockers prevent effects of overactive SNS on the heart, thus decrease arrhythmias - Used cautiously in stable HF, beneficial effects derive from decreased sudden death due to cardiac arrhythmia - Decreased catecholamine stimulation of heart - Possibly less remodeling of myocardium (less enlargement) - from cardiac contractility - Possible preservation of heart muscle cells: beta-blockers can interrupt the effects of overactive catecholamine stimulation that leads to the progressive heart failure as more cardiac myocytes die Hypertension - (Not first-line treatment) - Decrease CO due to decreased force/contractility and rate of contraction - The decrease in renin release in response to SNS stimulation is also advantageous in patients with high plasma renin activity - Beta-blockers may not work well for hypertension in black population. Open-angle glaucoma - relieve intraocular pressure reduce production of aqueous humor, topical Migraines - reduce frequency and intensity Performance anxiety (opera singers, horn players- decrease muscle tremors)

Influences on Drug Metabolism

Exogenous - Inhibition - Induction Endogenous - Pharmacogenetics - Disease - Sex - Aging

Exogenous Carcinogens

Exposure to carcinogens (occupational work) can lead to carcinogensis: - Furniture making --> wood dust --> sinonasal carcinoma - Rubber industry --> aromatic amines --> bladder cancer - Dye and textile production --> benzidine --> bladder cancer Exposure to foods or by products of cooking: - Aflatoxins --> hepatocellular carcinoma - Barbeque/Smoked meat --> Polycyclic Aromatic Hydrocarbons (PAH) --> gastric/lung cancer Exposure to viral agents and radiation is also carcinogenic.

Fibrosis Definition

Extensive deposition of collagen that occurs with some forms of injury and chronic inflammation.

Mechanisms of Apoptosis

Extrinsic/death receptor-initiated pathway - Requires cell surface 'death receptors' which are members of TNF family of proteins. - TNFR1 and Fas (CD95) - with appropriate ligand binding, caspases are cleaved and activated - FLIP is a protein which inhibits apoptosis Intrinsic/mitochondrial pathway - pathway is a result of increased mitochondrial permeability - In the normal cell, there are anti-apoptotic proteins that reside in the mitochondrial membrane (Bcl-2 and Bcl-x) - As the mitochondria are damaged, these are lost and replaced by pro-apoptotic members of the same family. - Cytochrome c leaks out of damaged mitochondria and cleaves/activates caspase-9 *An 'execution' phase takes place involving other caspases that dissolve the cell components. *Macrophages clear the cellular debris

Acute Inflammation Hallmarks

Exudate: - Inflammatory extracellular fluid rich in protein - cellular debris - specific gravity above 1.020 (goes along with structural changes in the vessel that occur with inflammation). Transudate: - fluid with low protein - few cells - specific gravity less than 1.012. (This is really an ultra filtrate of blood plasma). Edema: - Excess of fluid in interstitial spaces or in serous cavities - can be either an exudate or transudate. Pus: - referred to as a purulent exudate - rich in neutrophils, making it appear whitish clinically.

Neoplasia: Osteosarcoma

Femur has a large eccentric tumor mass arising in the metaphyseal region This is an osteosarcoma of bone These tumors most often occur in young persons (note that the epiphysis seen at the right is still present).

First Order Kinetics

First-order process (which most drugs follow) half-life (t1/2) - the time it takes to remove half of the drug from the blood is constant - because the enzymes (or other processes) are not saturated - (D < Km) of metabolic enzyme - therefore the rate of the process is dependent only on the concentration of the drug - a constant fraction (e.g. half) is metabolized (or eliminated) in a fixed time - >90% of the drug is cleared in 4 half lives ke is the elimination rate constant - unit of ke? per time (hr-1) t1/2 = 0.693/ke What is the meaning of ke = 0.1 hr-1? - 10 % of drug gone/hr IF THE CONC IS STEADY

Four-compartment model of drug distribution

Flow-Limited Drug Distribution: After administration of an intravenous bolus: - drug is delivered to various tissues via systemic circulation - fraction of the administered dose is initially highest in the vascular compartment (blood), but the blood fraction subsequently falls rapidly as the drug is distributed to the other tissue compartments - most vessel-rich tissues (i.e., tissues that are supplied by the highest fraction of the cardiac output) are generally the first to accumulate drug - However, the tissue compartments also vary in their capacity for taking up drug - Because the mass of the muscle group is larger than that of the vessel-rich group (VRG), the muscle group has a larger uptake capacity. But because the muscles are less well perfused than the vessel-rich group, this effect is manifested only after the drug has begun to distribute to the VRG - most poorly perfused group is the adipose-rich group, but this group has the highest capacity to accumulate drug. The peak level of drug in the adipose group is not as high as that in the muscle-rich group, because a significant amount of drug has been eliminated by metabolism or excretion before the adipose group begins to accumulate drug After the administration of drug has been completed, the reverse pattern is seen: - the drug leaves first from the vessel-rich group and then from the muscle and adipose groups, respectively - pattern emphasizes that adipose tissue can provide a significant reservoir of drug even after drug administration is discontinued. The drug in this example is thiopental, a barbiturate that can be used to induce general anesthesia THIS HAPPENS IN HIGHLY LIPID SOLUBLE DRUGS - A highly lipid soluble drug such as thiopental (lipid:water partition coefficient = 102:1) easily crosses lipid membranes and distributes out of the water compartment, i.e., has a high apparent VD - These drugs exhibit flow-limited distribution, i.e., their distribution is dependent on the rate of blood flow to a tissue - these drugs will distribute faster to the highly perfused organs and more slowly to the poorly perfused tissues. Note: Most drugs exhibit membrane-limited distribution --> distribution is limited by the drug's ability to cross cell membranes (lipophilicity)not by the rate of blood flow. Thiopental Experiment: Thiopental is highly lipid soluble, it crosses membranes easily and, as such, it exhibits flow-limited distribution, i.e., its distribution is dependent on the rate of blood flow to a tissue. Thus, thiopental will distribute faster to the highly perfused organs (such as the brain, kidneys, heart, lungs, adrenals, liver), than to the muscle group, and more slowly to the vessel poor group (poorly perfused tissues such as fat, bone, cartilage).

Edema

Fluid in the interstitial tissues (any tissue, organ or space) - Hydrothorax (pleural effusion) - Hydropericardium (pericardial effusion) - Hydroperitoneum (ascites) - Anasarca (severe generalized edema) Two major types: Inflammatory: result of increased vascular permeability Non-inflammatory: related to changes in hydrostatic and osmotic pressures and obstruction. Hydrostatic pressure: - pressure exerted or transmitted by water at rest - Fluids flow from higher pressure to lower. Osmotic pressure: - pressure required to prevent passage of water through a semi-permeable membrane from a region of low concentration of solutes to one of higher concentration of solutes Oncotic pressure: - form of osmotic pressure exerted by proteins in blood plasma that normally tend to pull water into the circulatory system. Increases in plasma hydrostatic pressure may result in edema Decreases in plasma oncotic pressure may result in edema.

Amyloidosis: Prognosis

For patients with systemic disease, prognosis is typically poor. AL-associated disease with multiple myeloma, median survival is approximately 2 years - indicate longer survival as chemotherapy improves. With reactive type amyloidosis, there is a slightly better prognosis

Thrombosis

Formation of a blood clot in: - uninjured vasculature - vessel with minor injury - pathologic disease Factors involved in thrombosis: VIRCHOW TRIAD 1. Endothelial injury 2. Abnormal blood flow (stasis or turbulence) 3. Hypercoagulability 1. Endothelial Injury: - Important factor (alone can cause thrombosis) - Important in arterial circulation - May initiate thrombosis with physical injury or functional abnormalities - Physical injury: Atherosclerotic plaque and inflammatory vascular injury - Dysfunctional injury: Hypertension and bacterial endotoxins 2. Abnormal Flow Normal flow is laminar - Stasis: Slow flow or no flow; contributes to venous thrombosis - Turbulence: Irregular flow; contributes to arterial thrombosis Mechanisms of stasis and turbulence in thrombosis: - Allow platelets to come into contact with endothelium - Prevent dilution of activated clotting factors - Retard inflow of clotting factor inhibitors - Promote endothelial cell activation 3. Hypercoagulability: - Alteration of the coagulation pathways that predisposes to thrombosis

Hemostasis Overview

Functions of normal hemostasis: 1. Maintain blood in fluid, clot-free state within normal vessels. 2. Induce a rapid and localized blood clot when necessary. Highly regulated process involving a series of stages, resting and activated enzymes and several mechanisms of control. Regulated by: - vascular wall - platelets - coagulation cascade Events of normal hemostasis (after injury): 1. Vasoconstriction: - result of reflex neurogenic mechanisms and by production of endothelin 2. Platelet activation: - result of exposure of subendothelial extra-cellular matrix - adhesion mediated by von Willebrand factor - platelets when activated undergo morphologic and functional changes, releasing contents of secretory granules 3. Platelet aggregation: - Forms primary hemostatic plug 4. Activation of coagulation cascade - result of tissue injury, release of tissue factor by endothelium in conjunction with factors released by platelets - Net result of coagulation cascade is formation of thrombin - Thrombin acts to convert fibrinogen to fibrin - Fibrin is a filamentous protein that stabilizes initial platelet plug along with the other factors and results in secondary hemostasis 5. Stabilization of platelet plug: - Polymerized fibrin and platelet aggregate to form a stable, permanent clot.

Site of Action of Barbiturates at the GABAa Receptor Complex

GABA-A receptor-chloride ion channel complex - Complex consists of five or more membrane-spanning subunits - GABA interacts at two sites between α and β subunits triggering chloride channel opening with resulting membrane hyperpolarization Binding of benzodiazepines and newer hypnotic drugs such as zolpidem occurs at a single site between α and γ subunits, facilitating the process of chloride ion channel opening - PAM (positive allosteric modulator) for GABA receptor Cl- channel (causes more frequency of opening) - Blocks Ca2+ channel opening - Blocks AMPA (subtype of glutamate receptor) The benzodiazepine antagonist flumazenil also binds at this site and can reverse the hypnotic effects of zolpidem

Muscarinic Receptors

GPCR - metabotropic 5 subtypes - slower activation - longer duration M1 (ganglia) - Gq → PLC (↑IP3, DAG) → ↑Ca (excitatory) M2 (heart) - Gi → ↓cAMP, ↑K conductance (hyper polarization --> slow down heart rate) (inhibitory) M3 (smooth muscle, glands) - Gq → PLC (↑IP3, DAG) → ↑Ca (excitatory)

Gangrenous Necrosis

Gangrene: necrosis of many tissues in a body part Left: - In this case, the toes were involved in a frostbite injury - This is an example of "dry" gangrene in which there is mainly coagulative necrosis from the anoxic injury Right: - This is gangrene of the lower extremity - In this case the term "wet" gangrene is more applicable because of the liquefactive component from superimposed infection in addition to the coagulative necrosis from loss of blood supply - This patient had diabetes mellitus

Morphologic Patterns of Acute Inflammation

General morphological patterns of acute inflammation. Much depends on the type of tissue and type of injury. - Congestion (increased blood in vessels) - Edema (fluid in interstitial spaces) - Influx of neutrophils and often tissue necrosis - Depending on the timing of the lesion, may also see evidence of repair already in progress Other patterns: Serous inflammation: - accumulation of thin fluid derived from mesothelial lining of a given cavity (peritoneal, thoracic) or from plasma - blister is an example. Fibrinous inflammation: - occurs in setting of greater vascular permeability so that larger proteins can escape, such as fibrin - fibrinous exudate appears red and granular grossly and histologically appears as pink threads - Pericarditis can be fibrinous. Suppurative or purulent: - accumulation of pus - often in setting of pyogenic (bacterial) infection - Pus includes neutrophils, necrotic cells, edema fluid - abscess is accumulation of pus in a localized area within a tissue.

Various Exons Encode Light and Heavy Chains

Genes that specify the LC and the HC are located on different chromosomes in the human genome kappa light chain locus: chromosome 2 lambda light chain locus: chromosome 22 heavy chain gene locus: chromosome 14 Within the gene (or locus), information for encoding a variable region is specified by: - 2 exons for the light chain (V and J) - 3 exons for the heavy chain (V, D, J) - J and D exons encode one of the hypervariable regions

Pharmacogenomics

Genetic polymorphisms exist in both: - Phase I (CYP2D6, CYP2C19, CYP2C9, CYP2B6, non-P50 enzymes) - Phase II (e.g. glucuronyl transferases, N-acetyltransferase, thiopurine S-methyltransferase, sulfotransferases) - biotransformation pathways and can lead to variability in drug response Polymorphisms can also lead to altered drug pharmacokinetics (absorption, DME) and pharmacodynamics (drug effect due to polymorphisms at receptors and other biomarkers). Identification of individuals with genetic polymorphisms in drug metabolism or response may require a change in therapy, depending on contribution to efficacy/safety. AmpliChip CYP450 Test - pharmacogenomic microarray

Cancer (Malignant Neoplasm) Grade and Stage

Grade Reflects morphologic and cellular characteristics of the tumor. - Degree of differentiation - Nuclear pleomorphism - Number of mitotic figures and abnormal mitotic figures - Amount of tumor necrosis Grading schema have been developed for many tumors: - carcinomas and sarcomas - different depending on the tumor type. Grade is especially important for predicting behavior for sarcomas. Grades typically range from 1 (better) to grade 3 or 4 (worse) Stage Defined as overall extent of tumor in the body. In most cases, prognosis is determined by stage. TNM staging system is most common: - T: tumor size - N: involvement of regional lymph nodes - M: Presence of distant metastases TMN varies widely depending on the tumor type and biology of the disease.

Granulomatous Inflammation

Granulomatous inflammation: - Pattern of chronic inflammation characterized by a collection of activated macrophages and giant cells that attempt to wall off an injurious stimulus. Granuloma: - Localized collection or focus of inflammation consisting of activated macrophages surrounded by a collar of mononuclear cells (lymphocytes and plasma cells) - center of the granuloma may be necrotic (caseating) or not (non-caseating) - Caseating granulomas are often associated with mycobacterial infection (tuberculosis) Classification of Granulomas Foreign Body Type: - Incited by inert (foreign) material such as suture material, silicon and talc. - often foreign material is too large to be phagocytosed by a single macrophage. - material does not usually incite any other specific type of inflammatory response. - material can typically be found in the center of granuloma under polarized light microscopically. Immune Type: - Caused by insoluble particles, often infectious and are capable of inciting a cell-mediated response. - inciting agent is engulfed by a macrophage, and through a series of interactions between T lymphocytes and the activated macrophage, a granuloma is formed. - Presentation to T lymphocytes by macrophage - Activated T cell produce IL- 2 which stimulates other T cells - Activated T cells produce IFN-gamma, which activates macrophages and transforms them into epithelioid and multinucleate giant cells

Chronic Inflammation: Granulomatous Inflammation

Granulomatous inflammation: - Specific type of chronic inflammatory reaction - means to contain the injurious agent - Examples: tuberculosis, leprosy, cat-scratch disease. Granuloma - area of inflammation specifically with epithelioid macrophage (histiocytes) that engulf and surround infecting organism or injurious agent - Lymphocytes and monocytes may also be present - center may be necrotic (referred to as 'caseous' usually in the setting of tuberculosis) - APC that presents a microbe (mycobacteria) - Macrophages produce IL-12 which stimulates T-cells (helper) which then secreted IFN-gamma which in turns activates macrophages to become specialized, group of macrophages that are collecting around microbe - Costimulation very specific type of response Grossly, a granuloma tends to be a focal lesion Seen here is a lymph node involved by granulomatous inflammation Differential diagnosis includes infections Caseating granulomas are often associated with tuberculosis infection

Infarction Morphology

Gross Red: Hemorrhagic - Venous occlusions - Dual circulation - Previously congested tissues - Re-perfusion White: - Occur in organs with end-artery circulation - heart, spleen, kidney Microscopic - necrosis

Liquefactive Necrosis: Brain

Grossly, the cerebral infarction at the upper left here demonstrates liquefactive necrosis --> dissolving of brain tissue Eventually, the removal of the dead tissue leaves behind a cavity --> not much scar tissue is formed in the brain, so instead leaves behind a cavity As this infarct in the brain is organizing and being resolved, the liquefactive necrosis leads to resolution with cystic spaces Liquefactive necrosis: type of necrosis typical of some infections, and hypoxic death in brain tissue - Dominant enzymatic digestion - Characterized by cell degradation into a liquefied mass

Tummor Suppressor Special Case: HPV

HPV is a DNA virus - more than 150 HPV genotypes Tumors caused by HPV: Benign: - Warts of hand and feet - Condyloma accuminata (genital warts) - Nasal and laryngeal papillomas Malignant: - Squamous cell carcinoma of cervix - Adenocarcinoma of cervix - Squamous cell carcinoma of anus - Squamous cell carcinoma of oral cavity - Squamous cell carcinoma of skin - Basal cell carcinoma of skin HPVs inducing genital neoplasms include: - HPV-6, 11: condyloma - HPV-16, 18: malignant tumors Common warts of hands/feet caused by: - HPV-1, 2, 4 Genes for Early (E) and Late (L) proteins are in the viral genome - E6 = p53 degradation, telomerase induction - E7 = RB degradation, transactivation of c-jun (proto-oncogene) degrades tumor suppressor genes :( insensitivity to growth inhibitory signals **p16 unregulated/overexpressed in cells infected with HPV p53 degradation --> p16 is attempting to make up for lost p53 and inhibit the cell cycle

Granulation Tissue Definition

Hall mark of healing Consists of formation of new blood vessels (angiogenesis) and proliferation of fibroblasts Microscopically - small capillary sized vessels are present - lined by plump endothelial cells - scattered spindle shaped cells (fibroblasts) are present producing collagen - tissue appears edematous (loose)

What happens if you cannot discriminate b/w self and non-self?

Harmless non-self: ALLERGY (HYPERSENSITIVITY) Self: AUTOIMMUNITY Altered self (malignant): CANCER

Hemodynamics: Hemopericardium

Hemopericardium: demonstrated by dark blood in the pericardial sac opened at autopsy Massive blunt force trauma to the chest may cause rupture of the myocardium and/or coronary arteries with bleeding into the pericardial cavity The extensive collection of blood in this closed space leads to cardiac tamponade

Hemodynamics: Hemorrhagic Stroke

Hemorrhages involving the basal ganglia area (the putamen in particular) tend to be non-traumatic and caused by HTN Hypertensive cerebrovascular accident HTN damages and weakens the small penetrating arteries A mass effect with midline shift, often with secondary edema, may lead to herniation.

Healing Response: Granuloma Scar

Healed scar associated with a silicone granuloma Inhaled silica persists indefinitely and produces an inflammatory reaction that is marked by prominent fibrosis Dense pink collagen is seen in the center of the nodule

Healing Response: Skin Excision

Healing biopsy site on skin seen a week following excision - Skin surface has re-epithelialized - Below this is granulation tissue with small capillaries and fibroblasts forming collagen (pink) - After a month, just a small collagenous scar will remain Primary and secondary intention (healing process) Going deeper into the dermis and subcutaneous: scar Just epidermis probably not gonna form a scar

Cutaneous Would Healing

Healing by first intention: - Clean uninfected surgical incision approximated by surgical sutures - Healing occurs with little scar formation. Healing by second intention: - Involves more extensive tissue loss often with a large tissue defect - usually a more intensive inflammatory response - more granulation tissue and wound contraction

Wound Healing

Healing is a fibroproliferative response that begins with 24 hours of the injury Induction of inflammation to remove dead tissue: - Inflammatory cells can fight off infection and also rid the area of subsequent dead cells and debris - If damage persists, then the inflammatory reaction may become chronic. Migration and proliferation of connective tissue: - Fibroblasts and endothelial cells proliferate in the first 24-72 hours to form a specialized tissue called granulation tissue. Angiogenesis (new vessels and growth of the new vessels): - referred to as neovascularization - New vessels likely sprout from pre-existing ones - Neovascularization is critical to repair and is a major component of granulation tissue. Scar formation: Three processes are involved in scar formation: 1. fibroblastic proliferation 2. extracellular matrix 3. tissue remodeling - process of scar formation goes beyond granulation tissu - TGF-beta appears to be the most important growth factor involved in scar formation as it promotes fibroblast proliferation and collagen synthesis - While some extracellular matrix degradation occurs during repair (remodeling), net collagen deposition is necessary for scar Tissue remodeling (Maturation): - balance of ECM degradation and collagen deposition - Matrix metalloproteinases (MMPs) are a family of proteins that act to degrade collagen Factors affecting healing - type of tissue and extent of tissue damage. - type, intensity, duration of the injury. - Inadequate blood supply and foreign bodies. - Underlying medical conditions (i.e., diabetes mellitus). - Nutrition (poor nutrition affects proper wound healing - affects collagen production for ex vit c) - Steroids (anti-inflammatory affects that can retard healing)

Petechiae

Hemorrhages that are small (1-2mm) Often involving skin or mucus membranes Associated with: - decreased numbers of platelets - platelet dysfunction - clotting factor abnormalities (less common)

Inclusions: Carbon

Here is anthracotic pigment in macrophages in a hilar lymph node Anthracosis is nothing more than accumulation of carbon pigment from breathing dirty air Smokers have the most pronounced anthracosis The anthracotic pigment looks bad, but it causes no major organ dysfunction.

Coagulative Necrosis of the Myocardium

Here is myocardium in which the cells are dying The nuclei of the myocardial fibers are being lost The cytoplasm is losing its structure, because no well-defined cross-striations are seen. Cytoplasm looks granular and less well defined First phase --> cytoplasm is brightly eosinophilic Atracting inflammatory cells Coagulative necrosis: - Most common type of necrosis - characterized by denaturation of cytoplasmic proteins, breakdown of cellular organelles, and cell swelling - Under the microscope, cells retain their basic outline for some time, however, the cytoplasm becomes more pink (eosinophilic), and nuclei breakdown and disappear.

Prostatic Hyperplasia: Higher Magnification

Here is one of the nodules of hyperplastic prostate. The cells making up the glands are normal in appearance, there are just too many of them.

Chemical Mediators of Acute Inflammation

Histamine: - Preformed and present predominantly in mast cells, basophils, platelets - Degranulation of mast cells occurs with physical injury and with several types of immune reactions. - causes vasodilation of arterioles and increased permeability of venules - mediates immediate transient response Seratonin: - Present in platelets and neuroendocrine cells - similar effects to histamine - released when platelets aggregate after contact with collagen (often exposed with injury) - PAF also stimulates release of serotonin from platelets Complement: - many proteins in plasma in inactive form which are activated and begin cascade of events. - anaphylatoxins: certain split products stimulate release of histamine from mast cells, thereby causing vasodilation and increased permeability - C5a: potent chemotactic factor for many leukocytes. - C3b acts as an opsonin. - Many regulatory proteins control this system. Kinin System: - plasma proteins that release vasoactive peptides (bradykinin) - bradykinin increases vascular permeability, vasodilation, pain Clotting System: - linkage b/w clotting system and inflammation: THROMBIN - Thrombin cleaves fibrinogen to generate an insoluble fibrin clot - Thrombin binds to specific receptors to mobilize selectins, produce chemokines, enhance expression of adhesion molecules, produce PAF and nitric oxide. Arachidonic acid metabolites: - role in inflammation and anti-inflammatory agents are directed along this pathway - LOOK AT PICTURE Platelet activating factor (PAF): - released from activated basophils (platelets, other leukocytes) - stimulates platelets - causes vasoconstriction and bronchoconstriction - at very low concentrations causes vasodilation and increased permeability - enhances leukocyte adhesion and chemotaxis. Cytokines: - two major ones involved in acute inflammation: TNF and IL-1 - Induce synthesis of endothelial adhesion molecules - Induce synthesis of other chemical mediators - Induce enzymes involved with matrix remodeling - Increase thrombogenicity of enodothelium - TNF acts to prime neutrophils Chemokines: - smaller proteins that act as chemoattractants for leukocytes - control migration of leukocytes in tissue Nitric oxide: - Potent vasodilator - Some antimicrobial actions - Reduces platelet aggregation and adhesion - Regulates leukocyte recruitment and other aspects of inflammation

Pathophysiology of Sepsis

Host-organism interaction self-propagating inflammatory cascade Direction, extent, duration of interaction based on: - Pathogen factors - Host factors Inflammatory response: PAMPs (LPS, peptidoglycan) interact with host cell specific receptors - Toll-like receptors - C-type lectin receptors - Retinoic acid inducible gene 1-like receptors - Nucleotide-binding oligomerization domain-like receptors Pro-inflammatory response: - Exaggerated inflammation leads to collateral tissue damage and necrotic cell death - Results in release of damage-associated molecular patterns (DAMPs) that perpetuate inflammation - positive feedback loop Anti-inflammatory response: - Immunosuppression - Inhibition of proinflammatory gene transcription - Impaired function of immune cells Activated neutrophils kill bacteria, but also... - Injure endothelium - cause vasodilation - Activate the coagulation cascade - Increase vascular permeability - Subsequent flow of protein rich edema fluid into lung and other tissues (EDEMA)

Clearance

How do you determine what dose rate to use to obtain a desired target plasma concentration? - need to know how much drug is being 'cleared' per time so you can replace it at that rate. Recall that most drugs undergo first order kinetics, so it is a constant fraction (not amount) that is being cleared per unit time A constant fraction of the Vd is being cleared per unit time. Clearance is the amount of the Vd that is completely cleared (by metabolism and elimination) in a given time. The units are volume/time e.g. ml/hr or ml/hr.kg for a per kg basis (to adjust for body mass). ke is the fraction of Vd that is cleared per time ke = 0.1 hr-1 --> 10% elimination/hr Clearance = CL = ke * Vd - CL = 0.69/t1/2 x Vd - ke = CL/Vd - t1/2 = 0.69Vd/Cl Important concept to help understand dosage to obtain a desired steady-state concentration of a drug. - dosing rate of a drug (mg/day) = clearance (ml/day) times the concentration at steady state (mg/ml), assuming complete bioavailability - applies well to steady state scenarios. Concept: Amount in will equal the amount out at steady state - If you know how many Liters are cleared completely per hour and the concentration (mg/Liter), you know how many mg/hr are being cleared. That is the amount out. Maintenance Dosing Rate: IV - Dosing Rate (amount in/time) = Css (amount out /volume) x CL (volume/time) Maintenance Dosing Rate: NON IV ADMINISTRATION - Dosing Rate = (Dose x F)/time = Css x CL

Hyperplasia

Hyperplasia: - Increase in number of cells in an organ or tissue (mitotically active cells) - Often leads to an increase in size and/or volume of organ - Often occurs with hypertrophy - Physiologic or pathologic - Pathologic hyperplasia can provide 'fertile soil' for more ominous changes (precancerous and malignant) Etiology 1. Physiologic: Hormonal or compensatory 2. Pathologic: Excessive stimulation (hormonal) Mechanisms: 1. Increased local production of growth factors 2. Increased levels of growth factor receptors on responding tissue 3. Activation of particular intracellular signaling pathways 4. Stem cell activation and renewal Clinical correlation: Female breast at puberty (physiologic): - Proliferation of glandular epithelium that occurs secondary to hormonal stimulation. Liver regeneration (physiologic or pathologic): - Increase in tissue mass after cell loss. - Different mechanisms may come into play depending on underlying etiology (partial hepatectomy versus cell loss because of chronic injury) - latter may involve stem cell commitment and differentiation. Endometrial hyperplasia (pathologic): - There is a delicate balance of estrogen and progesterone that controls the endometrial lining - When disturbed, the lining endothelium may proliferate abnormally - most important aspect of pathologic hyperplasia is an increased risk of changing to a precancerous or cancerous type of proliferation.

Hypertrophy

Hypertrophy: - Increase in the size of cells resulting in an increase in size of organ - Response to increased stimuli or increased demand in non-dividing (post mitotic) cells - cell becomes larger secondary to increased synthesis of structural components - physiologic or pathologic Etiology: 1. Increased workload (demand) 2. Increased stimulation Mechanisms: 1. Mechanical sensors result in production of growth factors and vasoactive agents 2. Increase in synthesis of proteins 3. Switch of contractile proteins from adult to fetal or neonatal forms 4. Re-expression of neonatal genes and products that are typically down-regulated at birth. *Hypertrophy and hyperplasia may occur together. Clinical correlation: Skeletal muscle hypertrophy (physiologic): - increased demand of exercise and body building leads to increase in skeletal muscle size - larger muscle fibers allow for this increased stress without injury Uterine muscle hypertrophy (physiologic): - uterus becomes greatly enlarged during pregnancy to accommodate the growing fetus - stimulus in this situation is hormonal - estrogen acts directly on smooth muscle of uterus to increase appropriate protein synthesis and cell size Cardiac muscle hypertrophy (pathologic): - Various stimuli act on heart to increase the size of the muscle fibers and size of the organ - in most instances considered pathologic - increased systemic pressures are usually implicated (HTN) and most commonly the left ventricle is affected (LV hypertrophy)

Exposure to Immunoglobulins from a Genetically Different Member of the Same Species

Identifies allotypic determinants Although members of a species share the same genes that specify the heavy and light chain classes and subclasses, the genes of one individual may vary slightly in DNA sequence from the same genes of another individual - termed alleles as they are actual differences in the genes carried by individuals When an individual carrying one allele is immunized with Ig synthesized in an individual with a different allele, these subtle amino acid differences can be recognized as foreign stimulating an immune response Region of the antibody recognized in this immune response is termed an allotypic determinant - differences can reside on the heavy and light chains and are found in primarily in constant regions. An example of allotypes in humans: - LCs encoded by the Km alleles of the kappa LC - Three alleles have been identified in humans - Km(1) allele encodes valine at position 153 and leucine at position 191 - Km(2) allele specifies alanine at 153 and a leucine at 191 - Km(3) allele has alanine at position 153 and valine at position 191 - Since each Ig monomer contains 2 identical LC, in a Km heterozygote (e.g., Km(2),Km(3)), both LC in an antibody will carry only one of the two allelic products (e.g., only Km(2) or only Km(3)). Kappa light chain gene is not the only human antibody gene in which there are allelic variants in the population - alleles of IgA2 (called A2m), IgE (Em) and all of the subclasses of IgG (G1m, G2m, etc)

Exposure to Monoclonal Antibodies

Identifies idiotypic determinants What is an idiotype? - antigenic determinant located in the antigen combining site of an antibody which is unique to each individual antibody The antibody recognizing the binding site is termed an anti-idiotypic antibody For example - anti-idiotypic antibodies can be made by a person if the individual is exposed to a sufficient concentration of an antibody and the immune system recognizes the antigen combining site as foreign - This might happen in two ways: 1. a person is given a monoclonal antibody as a therapeutic treatment 2. an individual might respond to an increased concentration of a particular antibody following an immune response Region of monoclonal antibody recognized is termed an idiotypic determinant.

Exposure to Immunoglobulins from Another Species

Identifies isotypic determinants Regions of the Ig molecule that differ between species are recognized when Ig from one species are introduced into another species Antibodies made in the human in response to mouse antibodies are directed towards antigenic determinants (epitopes) localized to the constant regions of the heavy and light chains of the mouse antibodies These epitopes are termed isotypic determinants because they are shared by an entire class or subclass of antibody (found on all mouse kappa light chains) The antibodies that detect these isotypic epitopes (rabbit anti-human kappa LC antibodies) can be used as reagents in the lab to determine the class or subclass of an uncharacterized antibody to characterize B cell leukemias or diagnose immunodeficiency diseases

Fate of a Thrombus

If one survives the thrombotic event, several things can occur over the following days to weeks: Propagation: - Further accumulation of platelets and fibrin, perhaps leading to complete occlusion of the vessel. Dissolution: - Removal of the thrombus by fibrinolytic system. Organization: - Involves an inflammatory reaction and fibrosis or a granulation tissue type reaction and recanalization (new lumina formation). Embolization: - Breaking off of a small piece of thrombus that travels to another site in the body

If the antagonist binds at an allosteric site...

If the antagonist/modulator binds at an allosteric site it can affect: - Kd or Emax or Both (of the agonist) Antagonism is non-competitive and saturable - antagonist binds to free receptor or receptor bound to drug at site that is not the active site (not the orthosteric site) Negative Allosteric Modulator: NAM - can cause a decrease in Emax OR - can cause a increase in EC50 (decreased affinity of receptor for drug/agonist) - can cause both of the above Positive Allosteric Modulator: PAM - can cause an increase in Emax OR - can cause a decrease in EC50 (increased affinity of receptor for drug/agonist) - can cause both of the above Examples: - Diazepam: PAM for GABAA receptors (potentiates effect of GABA) - Maraviroc: NAM for CCR5-Receptor (decreases receptor affinity for HIV)

Oral Administration

If the drug is given orally or by another route, the maximal plasma concentration is not achieved immediately, but only after absorption is complete. Thus, there is a slower rise to maximum. BUT, the decline is the same. So, t1/2 is the same Bioavailability: - fraction or percent of drug that is administered that actually enters the bloodstream. - Abbreviated F (Fraction available) Calculated, for oral dose, as the ratio of the areas under the curves for oral/iv - F = AUCoral/AUCiv What can affect bioavailability? - Change in 1st pass metabolism (gut/liver metabolism) - changes in p-glycoprotein (e.g. inhibition by other drugs)

Repair

If tissue injury is severe - typically including damage to parenchymal cells and surrounding stromal network (extracellular matrix components) - healing cannot be accomplished by regeneration Repair often involves deposition of collagen to form a scar Repair process includes includes: - Inflammation - Angiogenesis - Migration and proliferation of fibroblasts - Scar formation - Connective tissue remodeling

IgA Structure and Isotypes

IgA is expressed as a monomer on B cell surface and in serum Secretion: Multimer (dimer) in secretions - IgA dimer is held together by interchain S-S bonds and by the J chain and has multiple antigen binding sites. IgA reaches external secretions by transport through epithelial cells - Secretory IgA binds to a receptor on epithelial cells called the polyIg receptor and is internalized - Then it is transported through epithelial cells and dumped into secretions - As it is released, the polyIg receptor is cleaved and a portion remains attached to IgA as secretory component (or secretory piece) - carbohydrates of the SP hold the IgA dimer at the mucosal surface by binding to mucins and protect it from proteases. Two subclasses of IgA: IgA1, IgA2 - differ in their hinge region Hinge region of IgA1 is sensitive to proteases made by some respiratory pathogens which cleave and destroy IgA1 IgA2 is not sensitive to the protease In the blood, ratio of A1:A2 is 4:1 In mucosal secretions ratio is 3:2 which may be a consequence of destruction of A1 by some pathogens and commensal microorganisms

IgA Properties

IgAs primary role is to block entry of pathogens through mucus membranes. IgA is major Ig class in secretions such as: - tears - saliva - breast milk (protection of infant: passive immunity) - mucus One notable feature of IgA is that it is synthesized at a very high rate, almost at twice the rate of IgG. Transfer to a newborn is an example of passive transfer of immunity. IgA does NOT activate the classical complement pathway. Other effector functions include: - activity in neutralization of pathogens (like IgG) - phagocytosis, ADCC? - ability to diffuse into extravascular sites (like IgG).

IgE Properties

IgE has an epsilon HC - no hinge region - 4 constant region domains Some notable features of IgE are: - shortest serum half-life - lowest synthesis rate - primarily found on mast cells lining epithelial cell surfaces and is important in allergen removal and immunity to parasites - binds with high affinity to Fc receptors on surface of tissue mast cells or blood basophils or eosinophils - If large parasites are coated with IgE antibody, eosinophils can bind via their FcR, eosinophil can release toxic molecules that damage the parasite (ADCC) - degranulation causes vasodilation, smooth muscle contraction, release of mediators and influx of inflammatory cells to attack the parasite

Antibody Classification

IgG - present at highest concentration in blood - general purpose antibody that can activate complement cascade giving rise to opsonins, chemoattractant molecules, MAC IgE - termed a cytophilic antibody - very short serum half-life in the blood - much longer half-life when attached to membrane of mast cells, basophils, eosinophils - When cross linked by antigen it causes these cells to disrupt releasing inflammatory mediators, microbicidal proteins and proteases. IgD - found on membrane of developing B cells and is important in B cell development - IgD enhances mucosal immunity - IgD class-switched B cells enter the circulation to "arm" basophils and other innate immune cells with secreted IgD - cross-linking of IgD on basophils stimulates release of immunoactivating, proinflammatory and antimicrobial mediators. IgM - pentameric immunoglobulin having 10 antigen binding sites - found in blood and can enter the tissues during inflammation - potent activator of the complement cascade - natural antibodies i.e., those produced in the apparent absence of antigen are of the IgM isotype, These antibodies recognize carbohydrate antigens and some self-antigens. IgA - monomer in blood - dimer or higher order polymer in secretions - Secreted IgA contains two additional chains, J-chain and secretory component (SC) - principal mediator of mucosal immunity - serum IgA may be a driver and regulator of autoimmune diseases/immune over-activation - regulation of cytokines, effector cell function, and homeostasis

Immunoglobulin in Second Stage of Response

IgG, IgA, IgE As a B cell is proliferating in response to antigen, it may receive signals that induce the B cell to alter the isotype of Ig that is being synthesized B cell will stop synthesis of IgM/IgD and begin synthesis of IgG or IgA or IgE

Cytotoxic CD8+ T cells

Image shows effector CD8+ cytotoxic T cell recognizing a host cell displaying viral peptides in the context of MHC class I CD8+ T cells constantly surveil the human body looking for host cells displaying non-self peptides held by MHC class I molecules CD8+ T cell makes contact with the target cell by means of cell adhesion molecules and then secretes various toxic molecules to kill the virus-infected cell - TCR binds to viral peptide:MHC I complex - CD8+ corecepter on T-cell stabilizes TCR:MHCI interaction Mature Effector T cells DO NOT require a second (co-stimulatory signal) as is the case with mature naïve T cells

CD4+ TH1 Cells

Image shows one of the functions of an effector CD4+ TH1 T cell which is to help macrophages to cope with intravesicular pathogen such as Mycobacterium tuberculosis - this bacterium can impair the ability of the phagosome to mature and fuse with lysosomes to form the phagolysosome in which the bacterium is killed and digested In order to get help from a CD4+ TH1 T cell the macrophage presents mycobacterial peptides in the context of MHC class II to an effector CD4+ TH1 T cell - T cell secretes IFN-1 which binds to receptors on the macrophage membrane and signals the interior of the macrophage to increase its microbicidal activity CD4+ T CELLS HELP MACROPHAGES DEAL WITH MYCOBACTERIA

Dendritic Cell Activation, Maturation, and Migration

Immature DCs located throughout the body take up pathogens and/or antigens by: - macropinocytosis - receptor-mediated endocytosis - phagocytosis Stimulated by ligation of MAMPs with PRRs to migrate through the lymphatics to regional lymph nodes DCs arrive as fully mature non-phagocytic, APDCs that express both antigen (in context of MHC) and co-stimulatory molecules (B7) necessary to activate a naive T cell that recognizes the antigen - stimulating lymphocyte proliferation and differentiation

What happens if you immune system functions sub optimally?

Immunodeficiency Diseases - Increased susceptibility to infectious agents - Inability to detect and control neoplastic cells

General Structure of Immunoglobulin

Immunoglobulin monomer composition: - two identical heavy (i.e., big, ~ 440 or 550 amino acids long) polypeptide chains - two identical light (ie small; ~220 amino acids) polypeptide chains - All of the chains are covalently linked together by disulfide bonds (S-S) between cysteine residues - Igs are glycosylated proteins - Sometimes Ig monomers may be linked together Sequence of each heavy and light chain is divided into 110 amino acid long segments called domains - Each immunoglobulin domain shares certain characteristics with the other Ig domains such as an intrachain disulfide bond and conserved amino acids at particular positions in the sequence - each domain folds into a structure called an Ig fold - fold consists of two antiparallel beta pleated sheets held together by the intra-chain S-S (sandwich held together with a toothpick) - heavy and light chains associate through interactions between the Ig domains - Each domain has evolved to perform a specific function Hinge region - located between the CH1 and CH2 domains of the heavy chain - region varies in length in different HC and contains cysteine residues which allow linkage of the HC polypeptides by S-S bonds - hinge region is rich in proline residues: give flexibility to the two antigen binding arms which makes it easier for the molecule to bind to antigen - hinge makes the monomer particularly susceptible to proteolytic cleavage (papain and pepsin cleave in this region)

Immunoglobins/Antibodies: Mediators of Humoral Immunity

Immunoglobulins (antibodies) are synthesized by B lymphocytes Antibodies can be found: - on the surface of the B cell (membrane bound BCR) - secreted by the B cell Secreted antibodies are found in body fluids (which were once known as "humors") Humors include: - blood - tears - saliva - mucus in bronchial, genitourinary and digestive tracts Antibodies are the effector molecules of humoral immunity Each B cell produces a unique antibody that is specific for a particular antigen Monoclonal antibody: antibody made by a single B lymphocyte (clone) and its progeny Function of antibody molecules: bind and remove antigen

Antigenic Determinants and Immune Response to Immunoglobulins

Immunoglobulins, as glycoproteins, can function as immunogens stimulating an immune response (humoral) Note: An antigenic determinant detected in a humoral immune response is a region of a protein which is recognized and bound by an antibody Another name for a determinant is an epitope

Leukocytosis

Increased WBCs circulating in the blood and measured by the complete blood count (CBC). Common feature of infections Increased neutrophils (neutrophilia) w/bacterial infections Increased lymphocytes (lymphocytosis) w/viral infections Cytokines stimulate release of WBCs from the bone marrow. A left shift refers to release of premature neutrophils (bands) from the bone marrow and can be seen with bacterial infections

Additional Diversity in Immunoglobulins after Antigen Encounter

In the periphery: - if the B cell encounters antigen - B cell becomes activated in the peripheral lymphoid tissue (e.g., lymph node) After activation: - IgD is down regulated - Activation of the B cell generates signals that induce process of somatic hypermutation and the process of isotype switch - Isotype switch leads to a change in the class of antibody produced by the B cell - end result is the generation of antibody secreting plasma cells and memory B cells - Alteration in RNA processing alters the Ig from cell membrane-bound to secreted.

T Cell Development: CD4 and CD8 Selection

In the thymus early developing T cells express a TCR and co-receptors CD4 and CD8 Positive Selection (Cortical Thymus) - As T-cells they pass through cortex of the thymus early T cells are exposed to MHC class I and MHC class II bearing self-peptide by thymic epithelial cells - If the T cell recognizes peptide in context of MHC class I then it down-regulates CD4 and becomes a CD8+ T cell - If the T cell recognizes peptide in context of MHC class II it down-regulates CD8 and becomes a CD4+ helper T cell HELPER T CELLS: DISPLAY CO-RECEPTOR CD4 - BIND PEPTIDE:MHC CLASS II CYTOTOXIC T CELLS: DISPLAY CO-RECEPTOR CD8 - BIND PEPTIDE:MHC CLASS I

Circulatory Shock

Inadequate cellular oxygen utilization Diagnosis: - clinical - hemodynamic - biochemical signs NOT exclusively defined as hypotension Three Windows into the Body 1. Brain/Mental Status - cloudy, altered mental state 2. Skin - cold, clammy, mottled 3. Kidney/Urine Output - decrease, oliguria Tachycardia Elevated blood lactate

Physiologic Stress and Toxic Stimuli

Increased demand Decreased nutrients Increased or decreased stimulation Chronic irritation Reduced oxygen supply Microbial infection Metabolic alterations

Stimuli for Acute Inflammation

Infection - typically bacterial and fungal - occasionally viruses and parasites can initiate an acute response with neutrophils. Trauma - physical and chemical Tissue necrosis - Often secondary to ischemia

Neoplasia: Ductal Carcinoma Higher Magnification

Infiltrating ductal carcinoma of breast at low magnification appears to radiate from a central area of desmoplasia: collagenous component gives neoplasm a hard "scirrhous" consistency that is palpable Such an invasive carcinoma may be fixed to underlying chest wall, making it non-mobile Can mimic normal tissue: still trying to do what breast tissue down (forming malignant ducts/glands) Growing in hapasard way, no normal architecture Central scar of collagen = DESMOPLASIA - makes it a hard mass, reactive process to neoplastic process

Chronic Inflammation Overview

Inflammation of prolonged duration - weeks or months (sometimes years) in which active inflammation, tissue destruction and repair are occurring simultaneously - arises de novo or it can result from acute inflammation that has not appropriately healed/resolved - Usually onset is insidious (slow and non-dramatic) - Involves mononuclear cells (derived from reticuloendothelial system) and includes monocytes (blood) and macrophages (tissue), lymphocytes, plasma cells - Granulomatous inflammation is a special type of chronic inflammation

Chronic Inflammation: Cell Types Seen

Inflammatory reactions are not neatly categorized by cell type A variety of inflammatory cell types may be present, though one may predominate Seen here are mainly neutrophils, but there are also plasma cells, lymphocytes, and macrophages. Macrophages can phagocytose other cells as well as cellular debris Macrophages apart of chronic inflammation stimulating healing (M2) Fibrosis - tissue destruction Macrophage that has eaten two neutrophils

Exogenous Influences on Drug Metabolism

Inhibition of Metabolism - Can result in toxicity if metabolism required for inactivation, May require dosage adjustment if drug whose metabolism is inhibited has a narrow therapeutic range. - Can result in therapeutic failure if metabolism required for activity (prodrug --> active metabolite) - Most often observed with Phase I drug metabolism, especially P450-mediated reactions - Can result from drug-drug interactions, food-drug interactions (competitive inhibition) - Drugs with common metabolic pathways may interact (not all inhibitors are substrates for enzyme); interactions can be mechanism-based. Induction of Metabolism - Can result in toxicity if metabolized to toxic metabolite - Can result in therapeutic failure if drug is active and converted to inactive metabolite - Can result from drug-drug interactions, herbal-drug interactions, environmental-drug interactions (tobacco smoke)

Immune System: Two Integrated Arms

Innate Immune System: - conserved throughout evolution - origins in unicellular, primitive life-forms - rapid response - low specificity, pattern-recognition system - response is invariant (no memory): no matter how many times it encounters a particular agent it responds in same way - mediated by phagocytic cells and primitive lymphocytes that lack high specificity receptors. Adaptive Immunity: - slow response - high specificity, high affinity receptors on lymphocytes (B cells and T cells) - exhibits memory: responds more rapidly and more strongly to second or subsequent encounters with the same agent - after initial interaction with antigen a few high affinity B and T lymphocytes are preserved (memory cells) that are activated in response to a subsequent encounter with the same antigen

Inclusions: Lipid

Intracellular accumulations of a variety of materials can occur in response to cellular injury Here is fatty metamorphosis (fatty change) of the liver in which deranged lipoprotein transport from injury (most often alcoholism) leads to accumulation of lipid in the cytoplasm of hepatocyte

Hemodynamics: Intraventricular Hemorrhage

Intraventricular hemorrhage (IVH) Arose in the subependymal region (germinal matrix) of a 28-week gestational age newborn Germinal matrix region is very susceptible to such lesions at this period of development, leading to IVH as a complication of prematurity. Germinal matrix bleed: very fragile vessels in preterm brain

Nicotinic Receptors

Ion Channel - Ionotropic - binds two molecules of ACh --> opens the donut Cation pore (Na+, K+) Typically excitatory response (Na+ goes into the cell depolarizing the cell) Fast Onset Short Duration of Action

Neoplasia: Ductal Carcinoma

Irregular mass lesion: infiltrating ductal carcinoma of breast Center is very firm (scirrhous) and white because of the desmoplasia Areas of yellowish necrosis in portions of neoplasm infiltrating into the surrounding breast Can have areas of pseudopod branching into surrounding tissue unlike benign adenoma which is well circumscribed Breast Cancer: Most common - arises from ductal cells Such tumors appear very firm and non-mobile on physical exam.

Clinical Correlation: Necrosis Etiology

Ischemia - MI: coagulative - Ischemic Stroke: liquefactive - 64 year-old man with a history of HTN and high cholesterol has an episode of chest pain that radiates to the left arm. Myocardial infarction is prototype of ischemic injury and coagulative necrosis - 79 year-old man has a 'stroke' (cerebrovascular accident). The tissue distal to a blocked blood vessel will undergo cell death, liquefactive necrosis Tumors - Malignant and aggressive: coagulative Trauma - Peripheral tissues and pancreatitis: fat necrosis - 24 year-old man has a hard, nodule on his arm at the site of previous trauma. The microscopic findings are consistent with fat necrosis Infection - Tuberculosis: classic caseous necrosis - 34 year-old immunocompromised patient is short-of-breath with recurrent fevers. An enlarged hilar lymph node is noted and the patient is diagnosed with tuberculosis. Cut surface is yellow, friable and microscopy shows granulomatous inflammation with central necrosis

Hemodynamics: Cerebral Infarction

Ischemic Stroke Intermediate to remote infarct in the distribution of the middle cerebral artery Followed by liquefactive necrosis from loss of blood supply to the brain

Alternative V/D/J Exons Provide Diversity

Kappa locus - many V exons (approximately 40 functional exons) - each of V exons is preceded by a leader (L) sequence exon - Five alternative J exons - kappa constant region exon Each V segment is capable of specifying first ~95 amino acids of a variable region Each J segment is capable of specifying last 10 amino acids of a variable region. In a cell that is not a B cell (e.g., in a hematopoietic stem cell or in a T lymphocyte or in an epithelial cell): organization of gene segments is called the "germline" organization: V1 V2 V3.... V40 J1 J2 J3 J4 J5 C Lambda locus - similar organization to Kappa - there are four subclasses of lambda light chains so there are 4 slightly different constant region exons - Each constant region exon is preceded by a J segment - Thus, the germline organization for lambda is: - V1 V2... V30...J1 C1 J2 C2... - Note: The number of segments is not important, just the general concept of "multiple V segments" etc. Heavy Chain locus - ~40 V gene segments - ~23 D segments - 6 J segments - followed by constant region exons specifying each of the classes and subclasses of heavy chain (mu, then delta, then followed by the others - Not shown here due to space constraints are the multiple exons of each constant region - This is the germline gene organization

Amyloidosis: Morphology

Kidney: - Gross: variable; can be small, large or normal. - Microscopic: amyloid deposits are primarily in glomeruli Heart: - Gross: enlarged - Microscopic: subendocardial and myocardial deposits. Liver: - Gross: normal or enlarged - Microscopic: Space of Disse and in vasculature Other: - Nodules in tongue - deposition in peripheral nerves

Drugs that Affect Catecholamine Synthesis, Release and Termination of Effect

L-Tyrosine is actively transported into axoplasm of the neuron, where L-Tyrosine is converted first to L-DOPA by tyrosine hydroxylase (TH), and then to dopamine by aromatic L-amino acid decarboxylase (ALAAD). Dopamine is actively transported into synaptic vesicles, where it is converted by dopamine ß-hydroxylase (DBH) to norepinephrine (NE) Arrival of a nerve action potential at varicosity causes the influx of calcium ions, which promotes the exocytotic release of NE into the neuroeffector junction where NE can activate receptors on: - postjunctional smooth muscle or glandular cells (α1) - cardiac cells (ß1) - prejunctional neuronal membrane (α2) - inhibits further release of NE Uptake 1: - Action of NE is terminated by transport back into the variscosity - In the varicosity, NE can be stored in the synaptic vesicle or metabolized by monoamine oxidase (MAO) to inactive deaminated products. Uptake 2: - NE is also lost from neuroeffector junction by diffusion and by transport into the postjunctional cell - metabolized to normetanephrine by catechol-O-methyltransferase (COMT). Prejunctional and postjunctional sites of action of drugs that modify noradrenergic transmission at a sympathetic neuroeffector junction. Drugs that enhance or mimic noradrenergic transmission (green circles) 1. Facilitate release (e.g.,amphetamine) 2. Block reuptake (e.g.,cocaine) 3. Receptor agonists (e.g., phenylephrine) Drugs that reduce noradrenergic transmission (red circles) 1. Inhibit synthesis (1a, alpha-methyltyrosine: 1b, carbidopa; 1c, disulfiram) 2. Disrupt vesicular storage (e.g., reserpine) 3. Inhibit release (e.g., guanethidine) 4. Receptor antagonists (e.g., prazosin)

Amyloidosis: Tissue Damage

Large deposits of abnormal protein lead to pressure atrophy, loss of normal tissue and loss of function. May influence/block exchange of nutrients. Some speculation of toxic nature of amyloid deposits: - Oxidative stress - Formation of abnormal ion channels - Destruction of cell membranes

Hemodynamics: Thromboembolism

Large pulmonary thromboembolus seen in cross section of this lung Typical source for such thromboemboli is from large veins in the legs and pelvis (DVT)

Edema: Reduced Plasma Oncotic Pressure

Largely determined by albumin and can occur in two ways: 1. Excessive loss (often through the kidneys - proteinuria) 2. Reduced synthesis (with liver injury/disease or malnutrition) Clinical correlate: - 26 year-old man presents with lower extremity edema - found to have a kidney disease resulting in excessive loss of albumin termed nephrotic syndrome. - 68 year-old man has a long history of chronic alcohol abuse - liver is small and fibrotic, cirrhosis with abnormal/decreased production of albumin and other plasma proteins - explains in part, the extravasation of fluid into the peritoneal cavity.

Myeloid Cells in Innate Immunity

Left column - professional phagocytes whose job it is to uptake pathogens by a process called phagocytosis - phagocytosis: form of receptor-mediated endocytosis - endpoint of phagocytosis is death and dismantling of the engulfed pathogen - DCs continuously perform pinocytosis: drink the fluid that surrounds them - macrophage (MO) and dendritic cell (DC) are professional antigen-presenting cells: present peptides (resulting from destruction of pathogen proteins) on their surface held in MHC class II molecules to interact with CD4+ T cells - Macrophages and DCs are long lived cells and are found throughout the body, particularly below the barrier epithelia. - Neutrophils are the most prominent cells in the blood, leave the blood only when recruited by cytokines and chemokines produced by cells at site of infection (MO, DC), live for only a few days. Right column (eosinophil, basophil and mast cell) - mediator-releasing cells - granules in their cytosol contain pharmacologically active molecules - eosinophil releases lipid mediators, platelet-activating factor (PAF), and leukotriene C4 (LTC4)], and cytotoxic granule cationic proteins, major basic protein (MBP), eosinophil peroxidase (EPO), eosinophil cationic protein (ECP), and eosinophil-derived neurotoxin (EDN) - Eosinophils are involved in defense against parasites and contributes to inflammation - Eosinophils are largely located at the barrier epithelia - Basophils are also found mainly at barrier epithelia and release histamine, serotonin that induce inflammation, and heparin that prevents blood clotting - levels of eosinophils and basophils in the blood are very low - Mast cells are found below the barrier epithelia and around small blood vessels where they facilitate the escape of leukocytes from the blood into the tissues. - Mast cell secretory granules contain preformed mediators that are rapidly (within seconds to minutes) released into the extracellular environment upon cell stimulation: mediators include histamine, neutral proteases, proteoglycans, and some cytokines, such as tumor necrosis factor-alpha (TNF-alpha)

Chronic Inflammation: Foreign Body Giant Cell Reactions

Left: - example of a poorly formed granuloma associated with foreign material - Two foreign body giant cells are seen just to the right of center where there is a bluish strand of suture material from a previous operation Right: - foreign body type giant cell at the upper left of center adjacent to a segment of vegetable material aspirated into the lung - Acute inflammatory cells are also seen here likely associated with secondary bacterial infection from vegetable - Neutrophils: acute response responding to the bacteria on aspirated vegetable - Giant Cell: Chronic response to foreign body of vegetable

Chronic Inflammation: Granulomatous Inflammation Higher Magnification

Left: - two pulmonary granulomas - Granulomatous inflammation typically consists of epithelioid macrophages, giant cells (fused macrophages), lymphocytes, plasma cells, and fibroblasts - may be some neutrophils - no caseating necrosis (not TB) Right: - epithelioid cells around the center of a granuloma - get their name from pink cytoplasm similar to squamous epithelial cells - Their nuclei tend to be long and stringy.

Hemodynamics: Pulmonary Infarction

Left: Large thromboemboli can cause death Medium sized thromboemboli (blocking a pulmonary artery to a lobule or set of lobules) can produce the lesion seen here:hemorrhagic pulmonary infarction - infarct is wedge-shaped and based on the pleura - These infarcts are hemorrhagic because though the the pulmonary artery carrying most of the blood and oxygen is cut off, the bronchial arteries from the systemic circulation (supplying about 1% of the blood to the lungs) is not cut off. - Wedged shaped (vascularity) Right: - larger area of infarction produced by a medium-sized thromboembolus to the lung - This infarction has begun to organize at the margins - also possible to have multiple small pulmonary thromboemboli that do not cause sudden death and do not occlude a large enough branch of pulmonary artery to cause infarction - However, if there are many small emboli, particularly if they are showered to the lungs over a period of time, then they collectively may block enough small arteries to produce pulmonary hypertension

Hemodynamics: Pulmonary Embolism High Magnification

Left: Microscopic appearance of a pulmonary embolus (PE) in a major pulmonary artery branch Right: Pulmonary embolus is adherent to the pulmonary arterial wall If the patient survives, the thromboembolus will organize and, for the most part, be removed.

Caseous Necrosis

Left: This is the gross appearance of caseous necrosis in a hilar lymph node infected with tuberculosis The node has a cheesy tan to white appearance Caseous necrosis is really just a combination of coagulative and liquefactive necrosis that is most characteristic of granulomatous inflammation Right: This is more extensive caseous necrosis, with confluent cheesy tan granulomas in the upper portion of this lung in a patient with tuberculosis. The tissue destruction is so extensive that there are areas of cavitation (cystic spaces) being formed as the necrotic (mainly liquefied) debris drains out via the bronchi Caseous necrosis: - refers to a process largely correlated with tuberculosis infection that implies granulomatous inflammation with central necrosis - Caseous is a term used to describe the white, cheesy material that is seen grossly

Infection/Sepsis

Life threatening organ dysfunction due to a dysregulated host response to infection SIRS like state + evidence of infection = Infected - Adaptive response SIRS like state + evidence of infection + plus organ dysfunction = Sepsis - Maladaptive, dysregulated, excessive response Septic Shock: Sepsis + hypotension

Accumulations

Lipid accumulation - can occur in many organs and by different mechanisms. - Steatosis describes accumulation of triglycerides in parenchymal cells (usually liver) - Drugs, alcohol, toxins, disease can interfere with catabolism of FFA thereby causing a fatty liver. Excess protein within a cell - can lead to or be secondary to disease. - Mechanisms include: Increased reabsorption, increased synthesis, defects in protein folding Glycogen - can accumulate within tissues - occurs in diabetes mellitus and glycogen storage diseases - latter usually involving enzyme deficiencies. Pigments: - Both endogeneous (melanin, hemosiderin, lipofuscin) and exogeneous (anthracosis, tattooing) pigments can abnormally accumulate within cells. - Most of these pigments are present within macrophages and are visible on H&E stained slides as an intracellular brown or black substance

Organs of Drug Metabolism

Liver GI Tract Plasma Skin Lung Kidney Brain Heart Liver + GI Tract --> First Pass Metabolism (if given orally)

Coagulative Necrosis of the Adrenal Gland

Lost all nuclei --> pale appearance The area just under the capsule is spared because of blood supply from capsular arterial branches This is an odd place for an infarct, but it illustrates the shape and appearance of an ischemic (pale) infarct well.

Secondary Lymphoid Tissues

Lymph Nodes Spleen Mucosa-associated lymphoid tissues (MALTs) All secondary lymphoid tissue has same organization as shown the picture with some minor differences - Spleen does NOT have lymphatic supply or drainage - gut-associated lymphoid tissues do NOT have afferent lymphatic vessels but do have efferent lymphatic vessels Note the following features of the lymph node There are three areas: 1. outer cortex (pale yellow) --> B cells 2. central paracortex (blue) --> T cells 3. inner medulla (red) --> plasma cells, macrophages Lymph arrives via afferent lymphoid vessels that empty into the sub-capsular sinus which divides into several sub-cortical sinuses that divide the lymph node in segments similar to an orange Lymph node stroma is like a sieve where molecules and pathogens in afferent lymph percolate through the node coming in contact with various types of immune cell

Distribution of Lymphoid Tissues in the Body

Lymphatic vessels form a centripetal pathway that gathers lymphatic fluid and carries it back into the blood via the great vessels in the neck. Left side: thoracic duct enters into the left subclavian and internal jugular veins Right side: right lymphatic duct enters into the right subclavian and jugular veins Lymph nodes act as filters and serve as the location where immune cells congregate and the adaptive immune response is initiated.

Edema: Lymphatic Obstruction

Lymphatic vessels may also become occluded and lead to leakage of fluid: lymphedema Lymphedema may result from extensive parasitic infections that cause fibrosis and obstruction Cancer surgeries involve lymph node dissection (removing regional nodes) and lymphedema may result

Chronic Inflammation: Other Cells Involved

Lymphocytes - called into play by cytokines - act to continually activate macrophages and other leukocytes Plasma cells -develop from activated B cells - produce antibody to persistent antigen or against altered tissue components Eosinophils - involved in some chronic inflammatory reactions including parasitic infections - Eosinophils can also contribute to tissue damage in some situations (ADCC) Mast cells - participate in both acute and chronic inflammatory reactions - In chronic inflammation, their products may contribute to fibrosis

Lymphocyte Maturation

Lymphocytes mature in the BM or thymus and then gather in lymphoid tissues throughout the body Primary lymphoid tissues (thymus and bone marrow) - repertoire of T cells and B cells w/specific TCR or BCR respectively are generated - Any B cells or T cells expressing receptors that recognize self antigens are deleted in these primary lymphoid organs - Furthermore, in the thymus developing T cells are tested to make sure that their T-cell receptor (TCR) recognizes self MHC molecules T cells exiting the thymus are called naïve T cells - travel through blood and take up residence in the paracortical areas of secondary lymphoid tissues B cells leaving the bone marrow are termed transitional B cells and they travel to the spleen before entering the B cell zone (follicles) of secondary lymphoid tissues

Major Histocompatibility Complex (MHC) Molecules

MHC class I: - expressed by all nucleated cells - peptides loaded into MHC class I are derived from degradation of pathogen proteins in the cytosol (endogenous) by the proteasome MHC class II: - expressed by APCs only. - peptides loaded into MHC class II are derived from pathogens that have been up-taken from outside (exogenous) the cell by phagocytosis, killed and digested in the phagolysosome (endocytic pathway)

Hemodynamics: Saddle Thromboembolism

Main pulmonary trunk and pulmonary arteries to right and left lungs are seen here opened to reveal a large "saddle" pulmonary thromboembolus Such an embolus is usually fatal

Neoplasia: Heptocellular Carcinoma Higher Magnification

Malignant cells of this hepatocellular carcinoma (seen mostly on the right) are well differentiated and interdigitate with normal, larger hepatocytes (seen mostly at the left) Nuclei are abnormal N/C ratio is large

Inclusions: Lysosomal Storage Diseases

Many inherited disorders of metabolism can lead to accumulation of storage products in cells Seen here with Gaucher's disease involving spleen. The large pale cells contain an accumulated storage product from lack of an enzyme Lysosomal storage disease: accumulation of substrate due to enzyme deficiency

Cancer: Sustained Angiogenesis

Maximum diffusion for oxygen, nutrients, waste is only 1-2 mm Lack of oxygen in rapidly growing tumor cells stimulate 'normal' response of cells to hypoxia: increases angiogenesis. New vessels in tumors are leaky/abnormal due to haphazard growth and disorderly milieu - can lead to metastasis b/c cancer cells get into blood vessels more easily through leaky vessels

Drug Metabolism: Framework for Pharmacology

Mechanism of action Elimination Pharmacogenetics Drug Interactions Adverse Drug Reactions

Metaplasia of Esophageal Mucosa

Metaplasia of esophageal squamous mucosa has occurred here, with gastric type columnar mucosa at the left Acid reflux Barret mucosa creates mucin to protect from acid Squamous --> mucous producing cells

Metaplasia of Laryngeal Respiratory Epithelium

Metaplasia of laryngeal respiratory epithelium has occurred here in a smoker The chronic irritation has led to an exchanging of one type of epithelium (the normal columnar respiratory epithelium at the right) for another (the more resilient squamous epithelium at the left) - squamous metaplasia Metaplasia is not a normal physiologic process and may be the first step toward neoplasia Metaplasia: Adaptive response in which one adult cell type (typically epithelia) is replaced by another to better withstand external stresses. Review: - Epithelial (squamous, glandular) - Mesenchymal (fat, fibrous, muscle) - Neural - Melanocytic (neural crest)

Metaplasia

Metaplasia: - Replacement of one adult cell type by another - most common in epithelial tissues (example: glandular, columnar epithelium being replaced by squamous epithelium) - Occurs due to external stimuli/stress that are irritating - Epithelium changes to better withstand stress. - Originates at the stem cell cell: reprogramming - cell does not undergo a phenotypic change, stem cells are reprogrammed to differentiate along a different pathway or undifferentiated mesenchymal cells differentiate along a specific pathway. Etiology: - Irritation - Persistent stress Mechanisms: - Local cytokines, growth factors and ECM - Turning on of tissue specific differentiation genes in stem cells Clinical correlation: 1. Respiratory tract squamous metaplasia: - Bronchial epithelium is ciliated pseudo-stratified columnar type - toxins within the inhaled smoke provide an external stress that impairs that mucociliary ladder - result is a switch to more resilient squamous type 2. Esophageal metaplasia: - esophagus is lined by stratified squamous epithelium - In patients with gastric acid reflux, the normal squamous lining changes to intestinal type epithelium - metaplastic epithelium attempts to secrete mucins for protective purposes. While both of the above act as a protective mechanism for the external stimulus, continued irritation can lead to additional genetic abnormalities and cancer.

Neoplasia: Metastatic Adenocarcinoma Higher Magnification

Metastatic adenocarcinoma is seen in a lymph node Common for carcinomas to metastasize to lymph nodes First nodes involved are those draining the site of the primary neoplasm (sentinel nodes) Lymph node Black and little dots are the lymphocytes Looks like glands (do not belong) Colon cancer Adenocarcinoma of colon that makes glands that has spread to the lymph nodes via lymphatics

Drugs that affect catecholamine synthesis

Metyrosine L-Dopa/carbidopa

Cancer: Defects in DNA Repair

Microsatellites - few base pair repeating sequences, usually 1-6 base pairs in length - accumulate with unfaithful replication of DNA during "S" phase - daughter strand has a frame-shift mutation due to DNA polymerase slippage during replication - usually fixed my mismatch repair proteins. Microsatellite instability (MSI) - mismatch repair proteins (Mut S and Mut L) do not work properly - due to mutations in mismatch repair genes, MSH2 and MLH1, respectively - cannot correct micro satellite expansions due to replication slippage Knowing the MSI status of a colonic tumor is important because it has better prognosis and is treated less aggressively - cell will accumulate mutations and be targeted for apoptotic cell death (p53 regulation)

Neoplasia: Melanoma Higher Magnification

Microscopic appearance of a melanoma Large polygonal cells have very pleomorphic nuclei that contain prominent nucleoli The neoplasm is making brown melanin pigment.

Neoplasia: Lung Squamous Cell Carcinoma Higher Magnification

Microscopic appearance of squamous cell carcinoma with nests of polygonal cells with pink cytoplasm and distinct cell borders Nuclei are hyperchromatic and angular

Caseous Necrosis: Higher Magnification

Microscopically, caseous necrosis is characterized by acellular pink areas of necrosis Seen here at the upper right, surrounded by a granulomatous inflammatory process.

Acute Inflammation: Necrotizing Bronchopneumonia Higher Magnification

Microscopically, the extensive neutrophilic exudate of a necrotizing pneumonia is seen here Normal tissues are destroyed in this region - Destruction of the underlying tissue

Drug Effects on Cholinergic Receptors

Mimic --> Agonists Block --> Antagonists Enhance --> Potentiators

Chronic Inflammation Morphology

Mononuclear cells: - Macrophages - lymphocytes - plasma cells - Often lymphoid aggregates, simulating lymphoid follicles of a lymph node, are seen in tissues affected by chronic inflammation Tissue destruction: - occurs because of injurious stimulus as well as the inflammatory response itself. Repair and fibrosis: - scar tissue often forms replacing the normal tissue.

Effects of Direct Acting Cholinergic Stimulants

Muscarinic receptor stimulants

Necrosis Morphology

Morphologic correlate to cell death. Nuclear changes: - three characteristic morphologic patterns. - Pyknosis (nuclear shrinkage, increased basophilia) - Karyolysis (loss of normal chromatin, less basophilic) - Karyorrhexis (the pyknotic nucleus undergoes fragmentation) - The nucleus eventually disappears. Cytoplasmic changes: - Increased eosinophilia (more pink) - more 'glassy' appearance - vacuolation (holes, moth-eaten appearance) - calcification (late)

Systemic thromboembolism

Most systemic thromboemboli arise from mural thrombi in the heart or valve Can travel to a wide variety of sites including: intestines, kidney, spleen, extremities

Cholinergic Receptor Classes

Muscarinic - M1 - Peripheral Nerves, CNS - M2 - Cardiovascular - M3 - Smooth Muscles, Glands Nicotinic - Neuronal --> Ganglia, Adrenal Medulla, CNS - Muscular --> NMJ

Binding of Agonists and Antagonists to Nicotinic Ganglionic (Nn) and Neuromuscular (Nm) Receptors

Muscarninc blocking drugs - 4.4A Ganglionic blocking drugs - 6C NM blocking drugs - 10C

Tumor Suppressors: APC

Mutation of adenomatous polyposis cell genes involved in hereditary and sporadic colon cancers APC down-regulates of growth promoting signals (β-catenin) that otherwise induce proliferation factors (c-MYC, cyclin D, etc) - when APC is knocked out B-catenin can induce proliferation factors without resistriction Mutation can be germline (inherited) or somatic (acquired) [first hit] Second hit can be due to second allele becoming mutated or methylation abnormalities. In the colon cancer model, APC mutations occur early (adenoma) in the progression to cancer.

Affinity Maturation

Mutation process (somatic hypermutation) occurs after encounter with an antigen in order to optimize the response to the antigen Optimization is termed affinity maturation As the B cell clone proliferates and divides in response to antigen, the HC and LC genes encoding the antibody begin to differ among the B cells derived from the original clone due to mutation rate Some of the mutations may alter the antigen binding site: - Positive --> increasing affinity of the antibody for its antigen - No effect on the original interaction - Negative --> can cause loss of antigen binding Those B cells derived from the original clone that synthesize higher affinity antibodies begin to proliferate more rapidly and come to predominate in the response (affinity maturation) This phenomenon results in memory B cells which are "fine-tuned" to mount the most effective response the next time the antigen is encountered. Diversity in antibodies occurs during: 1. joining of gene segments prior to antigen encounter 2. process of somatic hypermutation after antigen encounter

Molecular Basis of Cancer

Mutations (nonlethal genetic damage) are key players in development of malignant tumors Genes are thought to be involved in carcinogenesis: - Proto-oncogenes - Tumors suppressor genes - Genes involved in apoptosis - Genes involved in DNA repair Transformation: - Disruption of a cell's regulatory pathways (involving mutations in above genes) - leading to de-regulation of cell proliferation and suppression of apoptosis - typically a multi-step process.

Tumor Suppressors: Retinoblastoma (Rb)

Mutations may be germline or sporadic Associated with development of retinoblastoma (both alleles inactivated) Also associated with other cancers (osteosarcoma, breast, bladder, lung) Mutations (inactivating) permit unregulated cell proliferation by allowing cells to escape G1 restriction check point. RB mutations occur in the E2F binding pocket - RB can no longer bind to E2F TF to inhibit it - constitutive transcription of S phase genes - no G1 check point essentially In addition, certain products of viruses (i.e. HPV) may inactivate RB

Receptor Reverse

Not all receptors may be required to be occupied by agonist to get to Emax Rt is not Emax This introduces 'non-simple systems' Explains why EC50 and KD may not be equal Kd comes from occupancy (receptor occupancy) EC50 comes from function (physiological response) Theoretical Example: - beta-adrenergic receptor control of cAMP and heart rate. - NE + BAR <--> NEBAR => cAMP => PKA => increase heart rate What if: A large excess of cAMP is able to be produced, and only 1% of max possible production of cAMP is needed to half-activate PKA? - i.e. there is excess synthetic potential for cyclic AMP and there is a linear relationship PKA => heart rate

Neoplasia: Cervical Carcinoma

Neoplasia is new and autonomous growth Note the mass of abnormal tissue on the surface of the cervix --> Invasive cervical carcinoma The term "tumor" is often used synonymously with neoplasm, but a "tumor" is nonspecific Not all dysplasia will progressive to invasive cancer Different serotypes of HPV may confer a higher grade dysplasia that cannot be fought off by the body's immune system - higher risk for developing invasive cancer

Neoplasia: Osteosarcoma Higher Magnification

Neoplastic spindle cells of osteosarcoma are seen to be making pink osteoid here Osteoid production by a sarcoma is diagnostic of osteosarcoma.

Neutral Antagonists

Neutral Anatagonists 3. If D has equal affinity (Kd=1 nM) for R* and (Kd=1nM) for R

Acute Inflammation: Cholecystitis

Neutrophils are seen infiltrating the mucosa and submucosa of the gallbladder in this patient with acute cholecystitis Can see neutrophils that have come out of the dilated capillaries

Nicotinic Antagonists Binding Sites

Nn receptor (Ganglionic cell receptor) - second N binding site (anionic binding site) - 6 carbon distance b/w two N binding sites Nm receptor (Muscle end plate receptor) - second N binding site (anionic binding site) - 10 carbon distance b/w two N binding sites allows for selectivity of antagonists - ganglionic blockers - 6C N distance - NMJ blockers (muscle relaxants) - 10C N distance

Hemodynamics: Normal Coronary Artery

Normal coronary artery No atherosclerosis Widely patent lumen that can carry as much blood as the myocardium requires Hemostasis: - Clot when needed and keep fluid when not needed to clot Endothelial cell integrity: IMPORTANCE OF ENDOTHELIUM - single cell layer that lines all bv and inside of heart also - endothelium is really integral in coagulation and inflammation which typically happen together) - pro-thrombotic responsibility and anti-thrombotic properties (on and off processes): balance Collagen exposure: platelet adhesion/activation - platelets change shape/confirmation and release factors to help is aggregation and clot formation - vWF Extrinsic Tissue factor (endothelial cell damage) - factor 7 (same as tissue factor) Intrinsic: negatively charged surface of platelets when confirmation changes Atherosclerosis --> disrupts flow (makes turbulent flow) - inflammatory cytokines from atherosclerotic plaque can cause activation/destruction/damage to endothelium

Phase I Nonmicrosomal Oxidative Drug Metabolism

Non-P450 mediated Oxidation - Alcohol - Aldehyde - Purines - Monoamines CHART***

Amyloidosis: Physical Properties

Non-branching fibrils Indefinite length 7.5-10.0 nm in diameter Structure is same in all types of amyloidosis. Cross beta-pleated sheet conformation is responsible for distinctive staining and birefringence For some fibrils this conformation is intrinsic, for others it is induced

Intravenous Infusion of Catecholamines: Direct and Compensatory Effects

Norepinephrine - a1, a2B in arteries --> vasoconstriction --> increase in diastolic BP - B1 in heart --> increase in contractility of ventricles --> increase SV --> increases in systolic BP - baroreceptor reflex due to rapid increase in diastolic bp (due to a1, a2B increasing TPR/afterload) --> increased stretch/firing of baroreceptors --> cardioinhibitory reflex --> decrease in HR (counteracts increase in SV leading to no change or decrease in CO) Epinephrine - low dose - B2 in muscle vascular beds --> vasodilation --> decrease in diastolic BP (decreased TPR) - B2 receptors are very sensitive to low doses of EPI, alpha receptors become more sensitive to EPI at higher doses - B1, B2 in the heart --> increased contractility --> increase SV --> increase CO --> increases in systolic BP - B1, B2 at SA --> increased HR (also contributes to increase in CO and increase in systolic BP) Isoproterenol - B2 in muscle vascular beds --> vasodilation --> decrease in diastolic BP - more decreased diastolic BP and mean arterial pressure and TPR than epinephrine graph because no alpha effects --> iso is beta selective, in the EPI graph still had minimal alpha1 stimulating leading to vasoconstriction against B2 vasodilation - B1, B2 in the heart --> increased contractility --> increase SV --> increase CO ---> increases in systolic BP - B1, B2 at SA --> increased HR (contributes to increase in CO and increase in systolic BP), HR is higher than EPI graph because no baroreceptor reflex present b/c of further decrease in TPR, in EPI graph, still minimal baroreceptor reflex present b/c of slight increase in BP acting against B1, B2 affects at SA to increase HR *NOTES: Effect of EPI on vascular tone is concentration dependent - Lower doses cause beta-2 mediated vasodilation leading to a decrease in DBP - as the dose increases alpha-mediated vasoconstriction predominates leading to an increase in DBP

Hemodynamics Overview

Normal cellular function is dependent on delivery of oxygen and nutrients and removal of waste products. Normal fluid homeostasis involves: - Maintenance of vessel wall integrity and normal endothelial function - Intravascular pressure (hydrostatic, oncotic) and osmolarity Alterations in either may result in movement of water across the vascular wall Edema: - Extravasation of fluid into interstitial space - Different clinical manifestations depending on amount and location - Pathophysiologically: several categories of edema Hyperemia: - Local increase of blood volume in a particular tissue secondary to active dilation of arterioles - tissue is grossly redder in appearance. Congestion: - Local increase of blood volume in a particular tissue - result of impaired outflow and is a passive process. *Congestion and edema often occur simultaneously Hemorrhage: - Extravasation of blood outside the vessel. Shock: - Cardiovascular collapse resulting in: - hypotension - hypoperfusion - cellular hypoxia There are several 'types' of shock.

Neoplasia: Cervical Dysplasia

Normal cervical squamous epithelium at the left Dysplastic squamous epithelium at the right Dysplasia is a disorderly growth of epithelium, but still confined to the epithelium.

Neoplasia: Cervical Dysplasia Higher Magnification

Normal cervical squamous epithelium at the left merges into dysplastic squamous epithelium at the right in which the cells are more disorderly - Larger, hyperchromatic (higher mitotic activity)

Neoplasia: Hepatic Adenoma Higher Magnification

Normal liver tissue with a portal triad is seen on the left Hepatic adenoma is on the right - composed of cells that closely resemble normal hepatocytes - but the neoplastic liver tissue is disorganized and does not contain a normal lobular architecture Beingn tumors typically mimic the normal tissue counterpart

Structural Similarities b/w Amphetamines and Ephedrine

Note similar structures to catecholamines Similarity b/w ephedrine and amphetamines especially methamphetamine. Resulted in possibility of diversion of ephedrine to methamphetamine Because of this: pseudoephedrine and phenylephrine have largely replaced ephedrine in OTC products *Pseudoephedrine is a diastereomer (non-mirror-image isomer) of ephedrine

Antibody Distribution in Human Body Diagram

Note the location of dimeric IgA and IgE at the barrier epithelia

Neoplasia: Squamous Cell Carcinoma

Note, the tumor has grown beyond the basement membrane and has invaded the submucosa Squamous epithelial cells are present in these large nests with pink keratin in the centers Epithelial derived cancer = carcinoma Keratin production in the middle from malignant squamous cell carcinoma Black cells are lymphocytes, body is responding to cancer

Edema: Increased Plasma Hydrostatic Pressure

Occurs mainly in situations of impaired venous return (Congestion/Impaired outflow) Clinical correlate: - A 32 year-old woman with a deep venous thrombosis of the lower extremity - thrombus impairs venous return in that extremity and fluid collects in the soft tissues of the leg and the leg appears swollen (congestion) - A 55 year-old woman with chronic hepatitis C has cirrhosis and ascites - Cirrhosis is fibrosis within the liver parenchyma that leads to an increase in pressure in the normally low-pressure portal system (restricting venous portal flow to liver) - mechanism partially explains why this patient has fluid that backs up and accumulates in the peritoneal space.

Metabolism

Once the drug is absorbed and enters the blood, it is distributed to its site of action and is also metabolized and excreted. Some drugs are eliminated chemically unchanged via the kidneys, lungs, or sweat. Most drugs are metabolized (chemically modified) prior to elimination. Metabolites may be inactive or active (more or less) relative to the parent drug - Some parent drugs are inactive (prodrugs) and only the metabolites are active - Metabolites may have different activities than the parent drug (i.e. work on different R and cause different [side] effects) Cytochrome P450 (CYP) enzymes in the liver often catalyze oxidation, reduction, or hydrolysis of drugs - phase I metabolism Many genes encode CYP enzymes and there are many variants of each gene product - 18 families of CYP genes Nomenclature: e.g. CYP2D6 - (family 2, subfamily D, member 6) - CYP families 1-4 most important for drug metabolism because of non-specificity Drugs are metabolized by specific CYP enzymes. Drug-drug interactions can occur because: * CYP enzymes can be induced by chronic drug treatment. - Induction means an increase in enzyme leading to an increase in enzyme activity * CYP enzymes can be inhibited by drugs * CYP activities usually decline with age and/or liver disease - elderly patients often metabolize drugs more slowly, or differently, than young patients. * CYP activities are usually increased in pregnancy. - No drugs can definitively be shown to be safe during pregnancy, but are often unavoidable. - Alterations in CYP activities can necessitate altering dosage. * Genetic makeup of individuals varies and the expression of specific CYP enzymes may be higher, lower, or be missing from an individual which - often why different patients have a much different response to a given drug (pharmacogenetics/pharmacogenomics)

Hemodynamics: Myocardial Infarction

One complication of a transmural myocardial infarction is rupture of the myocardium - most likely to occur in the first week between 3 to 5 days following the initial event - when the myocardium is weakest White arrow marks the point of rupture in this anterior-inferior myocardial infarction of the left ventricular free wall and septum Note the dark red blood clot forming the hemopericardium.

Acute Inflammation: Ulceration

One consequence of acute inflammation is ulceration. This occurs on epithelial surfaces Here the gastric mucosa has been lost, or ulcerated (acute gastritis --> pain) A larger ulcer and several adjacent smaller ones with surrounding erythema appear at the left of center.

Encoding Heavy Chain Isotypes

Order of the constant region exons that specify different classes and subclasses of HC Mu, delta --> followed by gamma , epsilon, alpha exons V, D, J segments are upstream to the left of the complex as shown on the slide - mu and delta are next to V/D/J exons Activation of the B cell by antigen can stimulate another DNA rearrangement event that alters the class of HC constant region expressed Switch sequences in the DNA - precede constant region exons encoding each class and subclass of heavy chain except delta Switch from IgM to a different class or subclass of antibody is influenced by specific cytokines secreted by T cells and acting on the B cell Rearranged HC VDJ segment is spliced next to one of the C region exons downstream of delta. DNA rearrangement changes the class of antibody expressed to either IgG (1,2,3,4), IgA (1 or 2), IgE Once the switch downstream has been made, there is no going back A B cell that has switched from IgM to IgG3 can't switch back to IgM (DNA is spliced out permanently) but it can switch further downstream to IgA or IgG2, for example.

Drug Transporters: P-glycoprotein

P-gp, Multi-drug Resistance 1 [MDR 1] protein Efflux transporter Located in apical membrane of: - intestine - liver - kidney - BBB Barrier to compounds getting into the blood, brain Intestinal Pgp drives efflux of drugs back into lumen of the intestine, limiting absorption - (i.e., basolateral-to-apical, blood-to-lumen Pgp can be inhibited or induced by specific drugs - May be co-expressed with CYP3A4 - Some overlap with CYP3A4 substrates - Some overlap with CYP3A4 inhibitors - Pgp can be induced by St. John's wort, rifampin, ritonavir Pgp expression - especially in liver and small intestine may be co-expressed with drug metabolizing enzymes and functionally interactive - CYP3A4 in particular - overlap between some (but not all) substrates Substrates - Digoxin - Diltiazem - Fexofenadine - Nifedipine Inducers - St. John's wort - Rifampin - Ritonavir Inhibitors - Amiodarone - Diltiazem - Erythromycin - Ketoconazole

Acute Inflammation: Acute Bronchopneumonia

PMN's seen here are in alveoli, indicative of an acute bronchopneumonia of the lung The PMN's form an exudate in the alveoli This patient had a "productive" cough because large amounts of purulent sputum were produced The source, the neutrophilic alveolar exudate, is seen here within the alveolar spaces No destruction/damage yet seen to endothelial pneumocytes

Cancer: Self Sufficiency in Growth Signals

PROTO-ONCOGENES A cellular gene which encodes a protein critical for cell proliferation in the signal transduction pathway. Activation mechanisms: 1. Point Mutation 2. Chromosomal Translocation: fusion protein 3. Chromosomal Translocation: increased promotor activity 4. Gene Amplification MECHANISMS OF ONCOGENE ACTION: - Oncogenes are classified according to the roles of the normal counterparts (proto-oncogenes). 1. Growth factors - May be products of oncogenic activity that stimulate cell growth - Examples: EGF (epidermal derived growth factor) 2. Growth factor receptors - Mutations result in unrestrained activation of the receptor and promote dysregulated growth - Example: erb B2 (HER2/neu) 3. G-proteins: Ras oncogenes (Signal Transducers) - Mutations in Ras proteins can reduce GTPase activity or stabilize the binding site - resulting in uncontrolled stimulation of Ras functions - RAF too 4. Nuclear Regulatory Proteins: - Transcription Factors (c-MYC) - Cell Cycle Components (Cyclin D)

Stages of Infection Response

Panel 1: Adhere to the epithelium - infectious agent must first adhere to epithelium before it can invade - Antimicrobial factors and specialized antibodies (SIgA) in mucosal secretions or sweat block adhesion of pathogen to epithelium and to kill it. - most efficient way of preventing infection is to prevent the pathogen from adhering to the surface Panel 2: Local infection, penetration of epithelium - skin is injured allowing the pathogen entry - local immune response at site of the infection is mediated by cells within the epithelium and dermis - antimicrobial factors and complement components in the tissue fluid may clear the infection. - local immune response may prevent the infection from becoming established - accomplished by resident phagocytes and local antimicrobial factors Panel 3: Local infection of tissues - local innate response is unable to contain and resolve the infection with local phagocytes and soluble antimicrobial factors - cytokines and chemokines from local immune cells act on nearby capillaries to recruit phagocytes from the blood as reinforcements - process is termed acute inflammation - DCs leave site of infection and travel through the lymphatics to the local lymph nodes where they present pathogen peptides to naïve T cells that have arrived from the thymus. - if local innate response is not successful, local sentinel cells signal for reinforcements and the adaptive immune response. Panel 4: Adaptive immunity - Antibodies produced by terminally differentiated B cells (plasma cells) enter blood and diffuse into the site of infection - Effector CD4+ or CD8+ T cells leave lymph node and traffic through the blood to the site of infection to mount attacks on the pathogen. - eventual clearance of the infection

Paraneoplastic Syndromes: 2. Immunologically-Mediated

Paraneoplastic Myasthenia Gravis and Lambert-Eaton Syndromes: - antibodies against tumor cell antigens cross-react with normal neuronal cell antigens OR - tumor cell antigens mimic neural cell antigens - body labels these antigens as foreign - as a result even normal neural cell antigens are attacked : produces bleeding, vascular occlusion, tissue hypoxia Common Causes: - Thymic carcinoma - small cell lung cancer

Autonomic Nervous System influence on Blood Pressure

Parasympathetic Effects (Ach stimulation of muscarinic M2 receptors) a) Heart: decreased heart rate - decrease firing of SA node - decreased conduction through AV node Sympathetic effects (NE and EPI) a) Heart (beta receptor mediated, B1 + B2) - increased heart rate (SA node) - increased conduction velocity (AV node and His-Purkinje system) - increased contractility (atrial & ventricular muscle) b) Blood vessels - arterial and venous constriction (alpha (a1 + a2B) receptor mediated) - vasodilation in skeletal muscle b.v. and splanchnic b.v. to the liver (beta2 receptor mediated) c) Kidney - increased renin secretion (beta1 receptor mediated) - increased Na/H2O retention: increase blood volume

Congestion

Passive accumulation of blood within a tissue - result of impaired flow and usually occurs together with edema - increased volume of blood results in increased hydrostatic pressures and fluid leakage.

PRRs and MAMPs

Pattern Recognition Receptors (PRRs) on DCs and MOs recognize microbe-associated molecular patterns (MAMPs) Professional APCs - DC - Macrophage (MO) - B cell PRRs that bind MAMPs: - Mannose receptor binds mannose arrays - Dectin-1 binds β glucans - DC-SIGN binds mannose and fucose arrays - DEC 205 binds CpG oligonucleotides - TLRs binds various MAMPs - CCRs (chemokine receptors) 1, 4, 2, 5, 6 - Glucan receptor binds glucose arrays - Scavenger receptor binds lipids - LPS receptor (CD14) binds lipopolysaccharide These receptors signal the interior of the cells causing the DC and MO release pro-inflammatory cytokines and chemokines - TLRs major signal initiator/sounding the alarm (leads to production of chemokines/cytokines specific to pathogen encountered to communicate that to the immune system) - other PRRs mentioned aid in pathogen phagocytosis Some of these receptors are termed endocytic receptors because they bind pathogens to the surface of the phagocyte making them easier to engulf.

Pattern for Serum Protein Electrophoresis

Pattern for serum protein fractionation If serum proteins are fractionated by electrophoresis, - majority of antibodies are found in gamma globulin fraction Originally called immune globulins

Aging and Drug Metabolism

Pediatrics - Phase I and Phase II reactions absent or much slower in neonates; mature at different rates - Dosing requirements for neonates and children different from adults Elderly - First pass extraction of drugs that are highly cleared by the liver (e.g. neuroleptics, triazolam and midazolam, propranolol) may be reduced due to age-related decrease in hepatic blood flow - Phase I biotransformations have some age-related decreases - Phase II biotransformations are generally not affected by age

Responsiveness to Drugs

People differ in their responses to drugs due to many factors (genetics, illness, etc). Even in a controlled population (age, sex, etc.) there are differences. ED50: effective dose - dose that causes an effect in 50% of people - Why do some people respond to low doses and others only to high doses? - What factors influence ED50? - Affinity, absorption, distribution, biotransformation, excretion Median Effective Dose

Chronic Inflammation Etiology

Persistent infection: - Involves certain microorganisms - some bacteria, some viruses, some fungi and parasites - are of low toxicity and often associated with delayed hypersensitivity reactions Prolonged exposure to toxic agents: - can be exogeneous or endogeneous Hypersensitivity diseases: - Immune reactions against one's own tissues - excessive and inappropriate activation of the immune system.

Hemodynamics: Petechiae

Petechial hemorrhages on epicardium of the heart. Petechiae are classically found when a coagulopathy is due to a low platelet count (primary hemostasis problem) Can also appear following sudden hypoxia

Endogenous Influences on Drug Metabolism

Pharmacogenetics Aging Effects of Disease on Drug Metabolism - Severe liver disease can result in impaired drug metabolism (decrease efficiency of hepatic enzymes) - Heart Failure results in decreased blood flow to the liver - important for drugs that are dependent on liver blood flow for elimination by hepatic enzymes Sex Differences observed in pharmacokinetics - Reported particularly for drugs metabolized by CYP3A but lack of consensus (may be due to inadequate power of studies to detect differences) - Lower dose of zolpidem for insomnia recommended in women due to slower rate of elimination than in men Effects of Race and Ethnicity on Drug Metabolism - variability in codeine pharmacokinetics (CYP2D6) - rosuvastatin (may be related to transporter) - more genetically related

Pharmacogenetics/Pharmacogenomics Definitions

Pharmacogenomics - general study of the many different genes that determine drug behavior Pharmacogenetics - study of inherited differences (variation) in drug metabolism and response Genetic Polymorphism - differences in DNA sequences that occur naturally in a population, with a frequency of > 1% Single Nucleotide Polymorphism (SNP) - polymorphism where alleles differ by replacement of a single nucleotide in the DNA sequence. Nonsynonymous SNPs - SNPs that change the amino acid sequence

Phases of Drug Metabolism

Phase I Reactions - Oxidation (microsomal P450-mediated and nonmicrosomal non-P450-mediated) - Reduction - Hydrolysis - generally resulting in increased polarity of molecule Phase II Reactions - Conjugation reactions

MAO Inhibitors

Phenelzine Selegiline

Alpha Blockers

Phentolamine (nonselective) Phenoxybenzamine (nonselective) Prazosin (alpha1) Tamsulosin (alpha1A)

Alpha agonists

Phenylephrine (alpha1) Clonidine (alpha2) Brimonidine (alpha2)

Selective α1 adrenergic receptor agonists

Phenylephrine: α1 agonist - Vasoconstrictor (presser) - Causes vasoconstriction of arteries and veins leading to an increase in BP with subsequent decrease in HR (baroreceptor cardioinhibitory reflex, increased vagal nerve activity w/decreased SNS output) - Nasal decongestant (rebound hyperemia) a1 agonists often used as decongestant in OTC preparations - Available orally - available as a nasal spray (reduces systemic side effects) - Problems with extended use: rebound hyperemia and ischemia, especially with nasal inhalers - What mechanism could account for this rebound hyperemia? --> receptor desensitization??

Drugs that act indirectly at SNS synapses via postsynaptic mechanisms

Phosphodiesterase (PDE) Inhibitors. - drugs can increase cAMP and cGMP 2nd messenger systems by inhibiting specific phosphodiesterase (PDE) enzymes that metabolize these second messengers - PDE inactivates cAMP and cGMP messengers - inhibiting PDE increases cAMP and cGMP levels in postsynaptic cell - ~12 PDE enzymes known so far PDE: Breakdown of cAMP and/or cGMP (to AMP and GMP) to end their intracellular signaling Both: 1, 2, 3, 10, 11 cAMP: 4, 7, 8 cGMP: 5, 6, 9 1. Aminophylline = Theophylline - Non-selective PDE inhibitor - target is predominantly, but not exclusively, PDE-4 - actions attributed to inhibition of PDE-4 - Increases cAMP (and to some extent cyclic GMP in certain cells) --> activation of PKA --> many effects --> relaxation of bronchial smooth muscle and stimulation of cardiac muscle, similar to those of beta-adrenergic agonists (such as Epi and NE) Uses: Asthma and COPD: - Relaxes bronchial smooth muscle (increases cAMP --> SM relaxation --> bronchodilation - But increases heart rate and may cause excess CNS stimulation and anxiety. What effect would aminophylline have on responses to other transmitters and hormones that act by increasing cAMP? - aminophylline was used extensively to treat asthma, bronchospasm and COPD - Aminophylline can markedly increase cardiac stimulation --> leading to possible arrhythmias - also produces CNS excitation --> possibly even convulsions in high doses. - also stimulates brainstem respiratory centers: used to treat apnea in preterm infants. How would a drug that blocks beta-adrenergic receptors affect the response to aminophylline? Aminophylline also inhibits certain cytokines (TNF-α) and leukotrienes: anti-inflammatory actions, reduces release of inflammatory cytokines Also blocks adenosine receptors and probably ↓inflammation - Inhibition of PDE is not aminophylline's only potentially important mechanism of action - in many tissues, it also potently blocks receptors for adenosine, which is a local autonomic nervous system messenger. Replaced by more specific drugs: - Some newer PDE-4 inhibitors decrease activity of certain cytokines and may be useful for treating some immune dysfunctions. 2. Sildenafil, tadalafil and vardenafil (Viagra, Cialis and Levitra) - Selective PDE-5 inhibitors: relatively specific for cyclic GMP - Nitric oxide (NO) directly stimulates guanylyl cyclase to produce cyclic GMP - PDE-5 inhibitor increases cGMP levels - NO --> Guanylate Cyclase --> cGMP --> PDE-5 --> 5'GMP (PDE-5 inhibitor would increase cGMP) - Increase in cGMP activates signal transduction pathway that relaxes smooth muscles in blood vessels in corpora cavernosa in the penis leading to an erection Sildenafil (sold as Revatio) - cGMP mechanism is also important in pulmonary vasculature - used to lower/decrease pulmonary vascular resistance to treat pulmonary hypertension and acute respiratory distress syndrome in adults and newborns. These drugs may also increase cerebral blood flow - cyclic GMP, LTP (mechanism for memory) - possible use in vascular dementias and AD is being studied In the eye, color vision is affected by GMP signaling

Acetylcholinesterase Inhibitors

Physostigmine Neostigmine Edrophonium Nerve gases: Organophosphates, Sarin Donepezil/Rivastigmine

Acute Phase Proteins

Plasma proteins synthesized in the liver increase during the inflammatory reaction. Cytokines act on the liver to up-regulate the synthesis of acute phase proteins Common acute phase reactants include: - fibrinogen - C-reactive protein (CRP) (can activate classical complement pathway) - serum amyloid A protein - mannose binding lectin Function as opsonins and aid in microbial destruction Serve as markers for some chronic inflammatory diseases and may indicate relapse or failure of therapy

B-cell Maturation: IgM

Polypeptides of IgM are synthesized by a B cell in the pre-B cell stag IgM is the first Ig made by any B cell Expressed at the cell surface of immature B cells in the bone marrow Because IgM is the first Ig made by a B cell, it is the first Ig made by a neonate

Barrier Epithelium and Portals of Entry

Portals of entry: - eye - nose, mouth (to GI and respiratory tracts) - anus - urinary meatus - vaginal introitus in females. Pathogens take the path of least resistance to enter the human body and that path is the portals of entry. The skin is a formidable barrier unless damaged The mucosal surfaces are a single cell thick - mucosal surfaces are preferred entry point Both skin and mucosae have their own defense systems

Cellular Components and Events of Acute Inflammation

Predominantly white blood cells/leukocytes: acute inflammation --> neutrophils Neutrophils predominate in first 24 hours eventually to be replaced by macrophages (after 24 hours through 48 hours) Leukocytes ingest and kill bacteria and other microbes Macrophages clean up the debris. Review of events as leukocytes travel to sight of injury: - Margination: Collection of leukocytes near endothelial surface within the vessel lumen --> slowing of blood flow during inflammation helps this process - Adhesion: Complicated process mediated by: selectins, immunoglobulin family, integrins and mucin-like glycoproteins. Complimentary molecules are exposed on leukocytes and the endothelium - process is mediated by cytokines. - Diapedesis: Transmigration of leukocytes across the endothelium - enhanced by presence of adhesion molecules present in the intercellular junctions (PECAM or CD 31). - Chemotaxis: leukocytes move in the tissue to the exact site of injury via a concentration gradient --> occurs via chemoattractants such as complement, leukotrienes, cytokines. - Recognition: leukocytes express several receptors that recognize external stimuli - stimuli include bacterial products (TLRs), opsonins (opsonin receptors), cytokines (GPCR). - Removal: phagocytosis of antigen, macrophages clean up the end of acute inflammatory response Adhesion Molecules Selectins - Selectins bind through their lectin domain. - act to mediate adhesion of leukocytes to endothelium - only expressed on cytokine-activated endothelium. - Mediate 'rolling' of leukocytes Immunoglobulin family - ICAM-1 (Serves as ligand for integrins on WBCs and has a major role in adhesion, arrest and transmigration) - VCAM-1 (Mediates adhesion of eosinophils, monocytes and lymphocytes). Integrins - Large family of proteins that mediate cellular interactions between other cells or between the extracellular matrix (surrounding tissue). - Integrins are expressed on leukocytes and platelets.

Adrenergic Transmission: Presynaptic Components

Presynaptic terminal is located at end of axon and contains organelles important for its specialized function Mitochondria: - great need to ATP - Supply ATP for many steps of the vesicle cycle Smooth ER - regulation of calcium stores - lipid production (important for vesicle production) No Rough ER present - reminder that proteins found in presynaptic terminal need to be transported from soma/cell body via axonal transport (can make enzymes needed for neurotransmitter production rate limiting) Presynaptic terminal is where the NTs are synthesized and packaged into vesicles Synaptic vesicles - small clear or small dense vesicles between 30-50 nm in sizes - Small vesicles store non-peptide NTs - Small vesicles release NTs in response to a very large increase in calcium in presynaptic terminal - Ca2+ dependent NT release: increase in calcium is due to membrane depolarization and subsequent opening of voltage-gated calcium channels - then calcium flows in due to a gradient differential (normal conditions: high extracellular calcium & low intracellular calcium) - Clear vesicles are recycled in presynaptic terminal following release of NT (NT is released but the vesicle is not) - Synaptic vesicle release of NT in response to membrane depolarization and calcium influx is fast and spatially precise.

Nonselective α-adrenergic Receptor Antagonists

Primary effect of these drugs is to produce vasodilation b/c they block existing sympathetic tone to arteries and veins Non-selective a1- and a2-adrenergic blockers - decrease in BP (via decrease in TPR) - usually accompanied by reflex increase in HR (baroreceptor caridioacceleratory reflex) Therapeutic use: - management of pheochromocytoma diagnosis - control of symptoms before surgery - blocks vascular effects of excess EPI/NE from tumor - also during surgery when tumor is being manipulated 1. Phentolamine: - competitive a1 and a2 antagonist - Note effect of phentolamine on HR and NE release (both increase because of block of a2A inhibitory negative feedback receptors on presynaptic SNS nerve terminals causes increase NE in synaptic cleft --> increased HR - can lead to an important side effect that prevents its routine use for treating hypertension - What side effect is that? Angina pain - Why? Because heart is beating faster - Therefore, Phentolamine increases work and O2 demands of the heart - Decrease in BP (via decrease in TPR) and block of presynaptic a2A receptors triggers an increase in the HR (caridoacceletory reflex and increase NE in synaptic cleft), which increases the work of the heart and its need for O2 - At the same time that the heart is working harder, the decrease in TPR results in less blood flow to the coronary vessels - Result: Angina or coronary O2 insufficiency 2. Phenoxybenzamine: - noncompetitive a1 and a2 antagonist - alkylates alpha-adrenergic receptors (it is not very selective so it also alkylates serotonin and histamine receptors) --> irreversible - takes 3-4 days for new receptors to be synthesized - Phenoxybenzamine can be used to block catecholamine effects at α-adrenergic receptors before surgery to remove catecholamine-secreting tumors (pheochromocytomas) - in the case of inoperable tumors, to attenuate the effects of catecholamines.

Lymphoid Tissues

Primary lymphoid tissues - bone marrow - thymus Secondary lymphoid tissues - lymph nodes - spleen - mucosa-associated lymphoid tissues Location of secondary lymphoid tissues at portals of entry to the human body Spleen is the secondary lymphoid organ that protects the blood circulatory system

Tumor Suppressors: p53

Principal mediator of growth arrest, senescence and apoptosis --> puts the breaks on cell cycle proliferation - p53 levels will rise in response to DNA damage, oncogenic activation and other cell stresses due to post-transcriptional modifications of p53 inhibitor proteins - if knockout, can not regulate cell cycle growth resulting in DNA damaged cells to continue replicating Many cancers will involve deletion of one or both alleles of p53 Li Fraumeni syndrome: - patients have inherited predisposition to develop cancers (in many organs) due to germline mutations in one allele and presuming a second hit prior to tumor development Mutated in: - 100% of small cell carcinomas - 80% of colon carcinomas - 50% of breast carcinomas The step at which p53 is inactivated during tumor progression depends on the specific organ and tumor **Chemo and radiation which induce DNA damage to kill the cancer cells will not be successful in cancers with p53 mutations

Paraneoplastic Syndromes: 4. Cachexia

Progressive loss of both fat and skeletal muscle tissue in site of adequate nutrient intake Elevated metabolic rate accompanied by weakness and anemia. Found in many cancer patients, no matter type of underlying malignancy One of greatest contributors to decreased quality of life

Drugs that Block Reuptake of Catecholamines

Prolong and Increase Action of NE 1. Cocaine and Amphetamines - Blocks both peripheral and CNS re-uptake of NE, DA and Serotonin (5-HT) - **Unlike amphetamine, cocaine probably does not increase release - Blocking reuptake prolongs neurotransmitter effect in CNS (leading to CNS excitation, including euphoria, anorexia) and in periphery (vasoconstriction and cardiac stimulation) Tolerance and High ABUSE liability - abused in Europe and N. America for >120 years - Cocaine also has useful local anesthetic properties and is used especially in ENT - DA effects 2. Desipramine and several other drugs used as antidepressants - selectively inhibit NE reuptake system in CNS and periphery - used as modestly effective antidepressants but do not produce the euphoric effects of cocaine or amphetamines - Why not? These drugs prevent actions of drugs that must enter NE axon through the NET re-uptake system (e.g., tyramine or ephedrine, or even amphetamine) - Tolerance does not develop - Not abused. Why not? They don't inhibit DA reuptake --> no euphoric effects Note: NE re-uptake inhibitors can block uptake of drugs that act inside the NE axon, including ephedrine-like drugs, thus diminishing their effects on NE neurotransmission.

Tolerance to Indirect-Acting Stimulants: Mechanisms

Prolonged or Repeated use of high doses results in: TOLERANCE: maydevelop rapidly, which usually leads to escalating doses. Why does tolerance develop? 1. Decreased Neurotransmitter availability - increased demands for release exceed synthesis capacity - Mechanisms of action of drugs that increase release can overwhelm the ability of synthesis to maintain adequate supply of NE and DA - Why? Synthesis inhibited by negative feedback inhibition of tyrosine hydroxylase (by high levels of catecholamines) 2. Possible Desensitization or Down-regulation of post-synaptic receptors Examples of drugs producing clinical tolerance - Amphetamines, Cocaine Consequences: - Requires increased dose to achieve similar effects - In some cases, can result in eventual exhaustion ("crash") --> in extreme cases can lead to psychiatric symptoms. - Especially a problem with amphetamines and can lead to escalating doses and dependence. - Decongestants (e.g., Ephedrine & Pseudoephedrine (especially nasal inhalers --> rebound hyperemia b/c of prolonged vasoconstriction)

Beta Blockers

Propranolol (nonselective) Metoprolol (beta1) Pindolol (partial agonist) Carvedilol (beta and alpha) Labetalol (beta and alpha)

Biochemistry of Apoptosis

Protein cleavage: - Caspases are a group of cysteine proteases that play an active role in apoptosis - When cleaved/activated, they activate other enzymes that directly degrade DNA, cleave other important proteins, and fragment the cytoskeleton DNA breakdown: - When DNA is fragmented during apoptosis, the breakdown products are 50 to 300-kilobase pieces - can be visualized on gel electrophoresis as DNA ladders - smear pattern is more typical of necrosis Phagocytic recognition: - Phosphatidylserine is expressed on membrane as well as other proteins that allow for their prompt phagocytosis

Reactive Systemic Amyloidosis

Protein: AA protein - consists of 76 aa - derived from a large serum protein called serum amyloid associated protein (SAA) Referred to as secondary amyloidosis because most patients have some underlying systemic inflammatory or autoimmune disorder or chronic type of infection - Most common underlying diseases: Rheumatoid arthritis, inflammatory bowel disease, tuberculosis, osteomyelitis and bronchiectasis. - Also associated with heroine abusers, so-called 'skin poppers' - Also associated with solid tumors: renal cell carcinoma, Hodgkin lymphoma Most patients present with: - renal disease - gastrointestinal or liver involvement

Primary Amyloidosis or AL-Amyloid

Protein: Immunoglobulin light chain Produced by immunoglobulin secreting cells, plasma cells. Associated with monoclonal B cell proliferation (example: multiple myeloma) and are systemic. Localized types of AL-amyloidosis are described: - associated with monoclonal plasma cells deposition - localized to a few sites: mucous membranes (conjunctiva), urinary bladder and respiratory tract. Most common type of systemic amyloid in the United States. Median age of onset is 60 years with a male predominance. Disease usually leads to multi-organ failure and death.

Amyloid of Aging (Senile Systemic Amyloidosis)

Protein: Transthyretin (TTR) - normal serum protein that binds and transports thyroxine and retinol - mutated form of transthyretin is responsible for other types of hereditary amyloidosis; however in SSA, the transthyretin is structurally normal (wild type) Age dependent (usually elderly individuals 80 years and older). Disease is typically asymptomatic and is found in vessels of GI tract, heart and lungs. Pathogenesis of this type is unknown Protein is found in normal or decreased concentrations. Protein fragmentation is suspected.

Hemodialysis Associated Amyloidosis

Protein: Β2-microglobulin Occurs in patients on long-term dialysis (for chronic renal failure). Deposition of Β2-microglobulin: - component of MHC class I molecule - present in high concentrations that was not filtered through dialysis membranes This type has decreased in incidence with newer filters.

Amyloid

Proteinaceous substance (fibrillar proteins) that form abnormally and deposit in extracellular space in a variety of organs This deposition results in tissue atrophy and damage

Hemodynamics: Thromboembolism of Pulmonary Artery

Pulmonary thromboembolus is occluding the main pulmonary artery Persons who are immobilized for weeks are at greatest risk The patient can experience sudden onset of shortness of breath. Death may occur within minutes.

Immune System Recognizes Danger and Induces Protective Responses

Recognition: - sentinel/innate cells: epithelium, macrophages (MO), dendritic cells (DCs) recognize danger signals and detect presence of infection - danger signals = conserved molecules on surface of bacteria, fungi, viruses, parasites - results in release of cytokines and chemokines to induce inflammation - If the local response is unable to resolve the infection, DCs migrate to secondary lymphoid tissues to activate the adaptive immune response: T cells and B cells to produce antibodies and effector T cells. Effector functions: - include phagocytes, antimicrobial proteins, antibodies, effector T cells, complement, Regulation: - When infection is resolved almost all immune cells are removed/die except very few memory B cells and T cells - shut down the immune response once the job it done/limit immune response - necessary for two reasons (1) activated immune cells can damage healthy cells and prolong inflammation which damages tissues (2) size of pool of immune cells must be kept constant Memory: - having been exposed to a pathogen (primed) - ability upon a second (recall) and subsequent exposure to same pathogen to respond more quickly, more strongly and more specifically What is an antigen? - any molecule recognized by the immune system.

Shock

Referred to as 'cardiovascular shock' Final common pathway for many potentially lethal clinical events Characterized by: - Systemic hypotension - Hypoperfusion - Impaired tissue oxygenation - Cellular hypoxia Types of Shock Cardiogenic: - result of myocardial pump failure. Neurogenic: - Not a common subtype - spinal cord injury, an anesthetic injury - loss of vascular tone and peripheral pooling of blood. Hypovolemic: - result of significant loss of blood or plasma volume - hemorrhage - burns Obstructive: - cardiac tamponade - pneumothorax - pulmonary embolism Distributive: - anaphylaxis - sepsis Shock associated with systemic inflammation: variety of insults associated - microbial infection (septic) - burns - trauma - pancreatitis - Common feature is an outpouring of inflammatory mediators that result in vasodilation and vascular leakage

Regeneration Definition

Refers to growth of cells and tissues to replace lost structures Occurs in tissues w/normal proliferative activity Requires an intact connective tissue scaffold composed of extracellular components that are critical for cell migration and normal polarity. Stem cells are required for regeneration Tissue restitution is identical to original components

Neoplasia: Renal Cell Carcinoma

Renal cell carcinoma arising in lower pole of the kidney Rairly circumscribed The cut surface demonstrates a variegated appearance with yellowish areas, white areas, brown areas, and hemorrhagic red areas Though these neoplasms are usually slow-growing, they can often reach a considerable size before detection because there is a lot of room to enlarge in the retroperitoneum and there is another kidney to provide renal function Presenting symptoms and signs usually include flank pain, mass effect, and hematuria.

Antibody Repertoire Generated Before Antigen Exposure

Repertoire of antigen binding sites actually is generated by B lymphocytes prior to antigen encounter Each B lymphocyte produces antibodies of a single antigen specificity Size of repertoire of antigen binding sites is limited only by the number of B cells found in the body at any one time - As new B cells replace old B cells, the antigen binding sites found in the pool change Clones of B cells bearing antibodies specific for a particular antigen are stimulated to proliferate upon exposure to that antigen. How is the immune system able to generate literally millions of different antigen binding sites? - answer lies in the genes that specify the LC and the HC as described above.

Physiology of the Sympathetic Nervous System

Responses to SNS Stimulation: Eyes a1 - pupillary dilation (mydriasis) Bronchi B2 - dilation Heart B1 - increased heart rate (SA node) - increased conduction velocity (AV node and His-Purkinje system) - increased contractility (atrial/ventricular muscle) - increased automaticity and rate of idioventricular pacemakers GI - decreased motility a/B - contraction of sphincters a1 Urinary bladder - decreased contraction of bladder wall muscles (SM relaxation) B3 - contraction of sphincters a1 Kidney B1 - ↑ renin secretion → ↑ Na+ and water retention (↑ Angiotensin II) Liver B2 - increased metabolism → increased glycogen breakdown and glucose release Skeletal muscles B2 - increased K+ uptake - increased glycogen breakdown Fat cells - lipolysis, release of free fatty acids skin (pilomotor muscle) a1 - piloerection (hair stands on end) Male sexual organs - ejaculation Prostate a1A - contraction Blood vessels a) constriction - all vascular beds (arteries and veins) a1, a2B b) dilation - vessels in skeletal muscles and vessels to the liver B2 Sweat glands - profuse sweating (cholinergic response) M Adrenal medulla - acts like a postganglionic cell (chromaffin cells) - releases NE (20%) and EPI (80%) --> circulate throughout body and function as hormones since their target is distant from the release site - allows for a prolonged and more powerful effect

Termination of NE Actions

Reuptake: Actions of most neurotransmitters are terminated by being transported back into axon from which it was released - Reuptake is the main mechanism for ending the synaptic actions of catecholamines - What is a prominent exception? ACh. Each neurotransmitter uses a specific reuptake system (transporter) - comprised of a general Na+/K+ ATPase: provides energy for pumping and specific recognition site (receptor) for specific neurotransmitter: - NET, DAT, SERT, GAT, GluT **These systems provide potentially important targets for selective drugs to modulate activity of specific neurotransmitters NE is transported with Na+ and Cl- down their concentration gradients into the cell - ion concentration gradient is maintained by the Na+/K+ATPase

Fever

Rise in body temperature by 1 to 4 degrees C. Typically associated with infection, but not always. In case of bacterial infection, bacterial products stimulate leukocytes to secrete cytokines (IL-1, TNF-a) - these cytokines increase cyclooxygenases that convert arachidonic acid into prostaglandins. - Prostaglandins act on the hypothalamus to reset core body temperature at a higher level. - thought that this rise in temperature helps to fight the infection (migrate bacterial and viral replication)

Hemodynamics: Fat Embolism

Rounded clear holes in the small pulmonary arterial branch in the lung characteristic of fat embolism Fat embolism syndrome is most often a consequence of trauma with long bone fractures It can also be seen with: - extensive soft tissue trauma - burn injuries - severe fatty liver - very rarely with orthopedic procedures. Bone marrow/fat embolism Can cause obstruction in itself but also can trigger coagultion (can lead to DIC) - upsets endothelium --> inflammation

Absorption

Routes of drug administration: - IV - SC - sublingual - IM - transdermal - Oral To enter the bloodstream (other than IV) and get to site of action, a drug must be absorbed across a lipid membrane (gut, cell membrane, placenta, blood brain barrier etc). Passive diffusion through lipid bilayer --> most drugs - most drugs don't have a transport mechanism and must cross membranes by passive diffusion - Only nonpolar molecules are easily absorbed across membranes - Polar molecules and ions are not (or very poorly) absorbed across membranes - To be absorbed, the drug ALSO needs to be water soluble - Completely non-water soluble drugs (e.g. mineral oil) are not absorbed by the body and pass straight through the GI tract. Many drugs are weak acids (R-COOH) or bases (R-NH2) which can exist either in uncharged (nonpolar) or charged (polar) form acid: R-COOH <=> R-COO- + H+ base: R-NH2 + H+ <=> R-NH3+ or R-NH3+ <=> R-NH2 + H+ QUESTION: How can a drug be polar enough to be water soluble and nonpolar enough to cross lipid membranes by passive diffusion? pKa of weak acid or base is very important!!! - Depending on pH and the pKa, the compound is mostly ionized (polar) or non-ionized (non-polar) Henderson-Hasselbalch equation pH - pKa = log (unprotonated/protonated) - good for both acids and bases - acid: pH - pKa = log (B-/A) - base: pH - pKa = log (B/BH+) Can lead to 'ion trapping' - e.g. aspirin (pK 5.4) or phenobarbital (pK 7.4)

Fight or Flight Response

SNS is a tonic system so its activity can be increased or decreased organ by organ or as a unit Not essential to life, but is necessary in stressful situations such as exercise, excitement, hemorrhage, etc. During stress the SNS is activated and all the physiological responses listed above (in the table) occur

Liquefactive Necrosis: Lung

Seen here are two lung abscesses (collection of neutrophils), one in the upper lobe and one in the lower lobe of this left lung An abscess is a complication of severe pneumonia, most typically from virulent organisms such as Staphylococcus aureus Abscesses are often complications of aspiration, where they appear more frequently in the right posterior lung

Acute Inflammation: Alveolar Exudate

Seen here is vasodilation with exudation - has led to an outpouring of fluid with fibrin into the alveolar spaces, along with PMN's The series of events in the process of inflammation are: 1. Vasodilation: leads to greater blood flow to the area of inflammation, resulting in redness and heat 2. Vascular permeability: endothelial cells become "leaky" from either direct endothelial cell injury or via chemical mediators (contraction) 3. Exudation: fluid, proteins, red blood cells, and white blood cells escape from the intravascular space as a result of increased osmotic pressure and increased hydrostatic pressure intravascularly 4. Vascular stasis: slowing of the blood in the bloodstream with vasodilation and fluid exudation to allow chemical mediators and inflammatory cells to collect and respond to the stimulus.

Pathways to Cancer Growth

Self Sufficiency in Growth Signals Insensitivity to Growth-Inhibitory Signals Defects in DNA Repair Evasion of Apoptosis Limitless Replicative Potential Sustained Angiogenesis Ability to Invade and Metastasize

Coagulation Cascade

Series of enzymatic conversions turning (inactive) pro-enzymes into activated enzymes Results in formation of thrombin which then converts fibrinogen --> fibrin (insoluble, fibrous protein) Highly regulated and requires co-factors, such as calcium and reactions tend to occur on a phospholipid complex Traditionally separated into intrinsic and extrinsic pathways converging with activation of factor X (not accurate in vivo) Activation of clotting (coagulation cascade) simultaneously activates fibrinolytic system which acts to limit the process of hemostasis Factors that limit coagulation 1. Dilution: coagulation factors are washed out with flowing blood 2. Decreased exposure to negatively charged surface 3. Anti-thrombotic properties of adjacent endothelium - Fibrinolysis

Distribution

Several different aqueous volumes that a drug may, or may not, have access to: - plasma - interstitial volume - intracellular volume - non-aqueous tissue reservoirs such as muscle or fat. The drug, once administered, can potentially find its way into several "compartments" Central Compartment: blood and other readily accessible fluids and tissues Some tissues are more well-perfused than others - brain and kidney > muscle > fat - drugs reach these tissues at different times and can redistribute from the well-perfused tissues to the less well-perfused tissues if their ultimate compartment is a less-well perfused tissue (e.g. fat) - distribution can be 'flow limited' (by blood flow) or membrane limited (by lipophilicity) - Vessel rich group = brain, kidney, liver, heart Example - a very lipophilic drug that passes membranes easily and is given i.v., distributes rapidly into well-perfused tissues (vessel rich group) - then slowly is leached out into less well-perfused tissues (e.g. muscle and eventually fat) - Note the non-linearity of the time axis - Depending on the site of action (i.e. where are the receptors), this drug could be rapidly acting for a short time or could take a while to have an effect. Plasma Protein Binding - affects the concentration of free drug. - Ex: Warfarin binds extensively (97-99%) to plasma proteins - Disease (e.g. liver, kidney) can change the amount of plasma proteins, changing the amount of drug bound (and free) - Other drugs that are also highly protein bound can compete with each other changing the free concentration of both drugs.

Systemic Effects of Inflammation

Several systemic effects of inflammation related to infection and/or injury The acute phase response (systemic inflammatory response syndrome) describes this systemic reaction. Response includes fever, neutrophilia, lethargy, increased muscle catabolism. Three macrophage derived cytokines: IL-1, IL-6, TNF-a are responsible for most of these effects

Distributive Shock

Severely decreased systemic vascular resistance. Cardiac output is typically increased in an effort to compensate for the diminished TPR Septic OR Non-septic (anaphylactic shock) --> hypotension

Summary of Relationships

Single Compartment Model: (i.v. bolus, rapid distribution) - Vd = D/Co - CL = ke x Vd Loading Dose: D = Vd x Ctarget Maintenance Dosing Rate: - Doral*F/t = CL * Css - Doseiv/t = CL * Css t - time interval

Purpura

Slightly larger hemorrhages (> 3mm) Similar causes as petechiae or secondary to: - trauma - inflammation - increased vascular fragility

Neoplasia: Fibroadenoma

Small fibroadenoma of the breast (fibrous and glandular tissue) Benign neoplasm More commonly found in younger women of reproductive age Dye was used as part of the diagnostic procedure Confined to the BM Generally well circumscribed Not infiltrating into the surrounding tissue May or may not be capsulated More slowly growing Can grow to be quite large Might be soft and mobile rather than firm and hard

Somatic Hypermutation

Somatic hypermutation occurs in the germinal centers of peripheral lymphoid tissue - Called somatic because it does not alter the germ cells of the individual (i.e., is not passed on to the offspring) Process targets the rearranged gene segments specifying the V regions of the HC and the LC polypeptides - mutation events occur at a rate much greater than normal somatic mutations altering 1 base pair per every 1000 base pairs every time the B cell divides - mutations occur at a rate of 1 in every 10^10 base pairs per cell division - If mutation occur at HVR can increase or decrease affinity of antibody for the antigen - If mutation occurs in the framework more likely to lead to a nonfunctional antibody

Muscle Fiber Atrophy

Some muscle fibers here that show atrophy The number of cells is the same as before the atrophy occurred, but the size of some fibers is reduced This is a response to injury by "downsizing" to conserve the cell In this case, innervation (denervation) of the small fibers in the center was lost. This is a trichrome stain.

Caseous necrosis

Specific type of coagulative necrosis in response to infection Caseous describes the gross appearance of tissue as cheese-like typical of tuberculosis granulomatous inflammation - A granuloma is a defense mechanism whereby the body tries to surround and wall-off an injurious agent (in this case, M. tuberculosis) - granuloma is a well-circumscribed area consisting of specialized macrophages and lymphocytes If a granuloma is caseating, it has a necrotic center

Neoplasia: Lung Squamous Cell Carcinoma

Squamous cell carcinoma Extends from hilum to pleura The black areas represent anthracotic pigment Cancer arising from metaplastic epithelial ALMOST ALL OCCUR IN SMOKERS - Central lesion, occurs in bronchial epithelium

Infection Control

Start broad spectrum antibiotics ASAP - increase in mortality rate each hour antibiotic therapy is delayed from onset of hypotension Culture data is not usually available at diagnosis Broad-spectrum IV antibiotics, set by local antibiogram Await culture data and then narrow If no culture data (often with pneumonia), once improved, may switch to oral, more narrow coverage

Alpha1 Receptor MOA Diagram

Stimulation of α1 receptors (GPCR) by catecholamines leads to activation of a Gq-coupling protein Activated a subunit (αq*) of G protein activates phospholipase C PLC leads to release of IP3 (inositol 1,4,5-trisphosphate) and DAG (diacylglycerol) from phosphatidylinositol 4,5-bisphosphate (PtdIns 4,5-P2) IP3 stimulates release of sequestered stores of calcium, leading to an increased concentration of cytoplasmic Ca2+ Ca2+ may activate Ca2+-dependent protein kinases, which in turn phosphorylate their substrates DAG w/Ca2+ activates protein kinase C (PKC)

Septic Shock

Subset of sepsis in which particularly profound circulatory, cellular and metabolic abnormalities substantially increase mortality. Septic Shock: Sepsis + hypotension Hypotension requiring treatment with vasopressors despite adequate resuscitation with 30ml/kg crystalloid to maintain mean arterial pressure >65 Shock with: - increased WBC (band cells) - liver function abnormality (elevated AST/ALTs) - elevated lactate (measure of lack of tissue perfusion) - evidence of kidney injury (increased creatinine)

Regulation of Beta-adrenergic Receptors

Sudden withdrawal of beta-blockers can lead to over-stimulation of heart - During long-term blockade, beta-receptors tend to increase in number (receptor up-regulation) - Usually of little consequence as long as the beta-blocker is present, but sudden withdrawal of the blocker can lead to overstimulation of the heart and severe consequences - Therefore, when a beta- blocker is going to be stopped, it should be gradually withdrawn unless being replaced by another beta- blocker Desensitization of adrenergic receptors to chronic use of agonists: - Phosphorylation of G-protein coupled receptors during sustained stimulation leads to decreased sensitivity and response. - Internalization of receptors --> reversible --> irreversible --> degradation - Why is desensitization important? (Think of beta, alpha-1 and alpha-2 receptors and the drugs that target them) Figure: - Rapid desensitization and longer term down-regulation of b-adrenoceptors Panel A: Response to a b-adrenoceptor agonist vs time. Duration of exposure to a constant concentration of agonist is indicated by the bar at top. The break in the time axis indicates passage of time in the absence of agonist - Desensitization refers to the reduced cAMP response after several minutes in the continued presence of agonist - Restored response is observed after a brief period (typically several more minutes) in the absence of agonist Panel B: Agonist-induced phosphorylation (P) by a G protein-coupled receptor kinase (GRK) of carboxyl terminal hydroxyl groups (-OH) of the b-adrenoceptor - This phosphorylation facilitates binding of a protein, b-arrestin (b-arr), which prevents the receptor from interacting with Gs - Removal of agonist for a short period of time (on the order of several minutes) allows dissociation of b-arr, removal of phosphate (Pi) from the receptor by phosphatases (P'ase), and restoration of the receptor's normal responsiveness to agonist - Physiological: Desensitization-Resensitization Cycle (Brief) Panel C: Agonist-induced endocytosis and endocytic membrane trafficking of receptors - Beta-arrestin promotes receptor binding to endocytotic structures in the plasma membrane called coated pits - After short-term agonist exposure, receptors primarily undergo dephosphorylation by phosphatases (P'ase) and recycling, promoting rapid recovery of signaling responsiveness - After longer-term agonist exposure, receptors that have undergone endocytosis traffic to lysosomes, promoting the process of receptor down-regulation - Pharmacological Desensitization (Longer-term)

Amyloidosis: Clinical

Symptoms of amyloidosis are variable - patients may have no symptoms - vary depending on extent of amyloid deposition and on underlying disorder. General symptoms: - Fatigue - weight loss - occasionally syncope. Cardiac: - symptoms associated with arrhythmias - shortness of breath (often associated with underlying heart failure, CHF) Renal: - proteinuria (nephrotic syndrome) - edema - symptoms related to renal failure. Gastrointestinal: - Malabsorption - diarrhea - dysphagia (difficulty swallowing)

SIRS

Systemic Inflammatory Response Syndrome Two or more of the following: SIRS Criteria - Body temp >38 or <36 C - HR >90 - Tachypnea, manifested by RR>20, or hyperventilation as indicated by PaCO2 <32mmhg - WBC increase >12k or <4k

Septic Shock

Systemic immune reaction to bacterial or fungal infection Characterized by: - vasodilation - pooling of peripheral blood - severe hemodynamic derangements Etiology and Pathogenesis of Septic Shock Hospital acquired gram+ or gram- bacteria Predisposing factors: - diabetes mellitus - cirrhosis - leukopenia - invasive devices - prior treatment with steroids Sites of initial infection: - lungs - genitourinary system - gastrointestinal system - with spread to bloodstream Pathogenesis is not completely understood Inflammatory mediators: - Microbial cell wall substances trigger an inflammatory cell reaction (LPS) - Inflammatory cells release chemical mediators: TNF, IL-1, IFN, prostaglandins, PAF - Chemical mediators activate endothelia - Activation of complement enhances pro-inflammatory state - Activation of coagulation cascade: directly (some chemical mediators via Factor XII or indirectly through endothelia) Endothelial activation: - Consequences include: vasodilation, increased permeability, thrombosis - Pro-inflammatory state may alter expression of some factors promoting coagulation and thrombosis --- Increased tissue factor production --- Decreased production of anti-coagulation factors - Increased NO production (contributing to vasodilation) Metabolic: - Hyperglycemia resulting from several mechanisms: --- Promotion of gluconeogenesis --- Suppression of insulin release --- Promotion of insulin resistance in liver and other organs Signs and symptoms of Septic Shock: Sepsis - Fever - tachycardia, tachypnea - decreased blood pressure - warm skin (and flushed initially due to peripheral vasodilation) - oliguria (decreased urine output)

Amyloidosis: Classification

Systemic: Involves more than one organ system (generalized). Localized: Deposits limited to a single organ. Controversy as to how to classify amyloidosis Some classify according to biochemical protein/fibril Some classifications are based on clinical disease

Roles of Effector T cells in Cell-mediated and Humoral Immunity

T cell-mediated immune responses are directed principally at intracellular pathogens CD8+ T cells - Destruction of infected cells by cytotoxic - direct killing, cellular toxicity - CTL CD4+ TH1 - Destruction of intracellular pathogens in macrophages activated by CD4+ TH17 - recruit neutrophils to sites of infection early in the adaptive immune response - response aimed mainly at extracellular pathogens. CD4+ TH2 - induce switch to production of IgE antibodies - involved in activation of effector responses aimed against extracellular multicellular parasites such as helminth worms TFH - contribute to humoral immunity by stimulating the production of antibodies by B cells in secondary lymphoid organs and inducing class switching - can produce cytokines characteristic of TH1,TH2 or TH17 cells - All classes of antibody contribute to humoral immunity, which is directed principally at extracellular pathogens - Both cell-mediated and humoral immunity are involved in defense against most infections Regulatory T cells (TREG) - tend to suppress the adaptive immune response - important in preventing immune responses from becoming uncontrolled (at end of infection and in preventing autoimmunity

Cardiovascular Parameters that Influence Blood Pressure

TPR = Total Peripheral Resistance - resistance of the entire systemic circulation (relates to the tone in the arteries) CO = Cardiac Output - amount of blood pumped out of the left ventricle each minute SV = Stroke Volume - amount of blood pumped out of the left ventricle with each heart beat HR = Heart Rate - number of heart beats each minute VR = Venous Return - amount of blood flowing from the veins into the heart (right atrium)/minute Venous tone - the level of constriction in the veins Blood volume is regulated by the kidneys

Cancer: Insensitivity to Growth-Inhibitory Signals

TUMOR SUPRESSOR GENES - Genes that normally exert negative regulatory control of cell growth - Encode negative transcriptional regulators of cell cycle, signal transducing molecules, and cell surface receptors. - 2 alleles must be knocked out for tumor formation (only 1 allele, a heterozygous state, is sufficient for protection) --> recessive manner --> two hit hypothesis - Loss of heterozygosity (LoH) in a tumor suppressor predisposes to cancer Examples: - Rb - p53 - APC

Cancer: Limitless Replicative Potential

Telomeres = short repeats of DNA at extreme ends chromosomes - not fully replicated with each cell cycle. As telomeres shorten - perceived as DNA damage and the cell initiates cell cycle arrest If no repair - telomeres get critically short - chromosomes fuse ends - ultimately apoptosis. Maintenance of telomeres - through reactivation of telomerase - seen in nearly all types of cancers Telomerase is present in stem cells

Testicular Atrophy

Testis at the right has undergone atrophy and is much smaller than the normal testis at the left.

Prostatic Hyperplasia

The normal prostate is about 3 to 4 cm in diameter. The number of prostatic glands, as well as the stroma, has increased The pattern of increase here is not uniform, but nodular This increase is in response to hormonal manipulation, but in this case is not a normal physiologic process Hyperplasia: Adaptive response in which there are increased numbers of cells (cells are normal, just more of them!) - physiologic or pathologic - often goes along with hypertrophy

Cardiovascular Effects of Catecholamines in Humans - Low Dose

Therapeutic doses: 0.1-0.4 μg/kg/min IV or 0.5-1.0 mg SC)

Hemodynamics: Bowel Infarction

The small intestine is infarcted Dark red to grey infarcted bowel contrasts with the pale pink normal bowel at the bottom. Some organs such as bowel with anastomosing blood supplies, or liver with a dual blood supply, are hard to infarct This bowel was caught in a hernia and the mesenteric blood supply was constricted by the small opening to the hernia sac - mechanical cause

Allelic Exclusion

There is only one functionally rearranged LC locus and one functionally rearranged HC locus in each B cell. How is this accomplished when each B cell has 2 kappa and 2 lambda LC loci and 2 HC loci? - If more than one locus rearranged functionally, then each B cell would express a mixture of antibodies - This is prevented by a process termed allelic exclusion Allelic Exclusion: Once a functional gene has been generated by rearrangement --> rearrangement of other LC or HC loci is halted - Failure to form a functional HC locus by incorrect splicing of V/D/J segments is followed by rearrangement of the second HC locus - If this second try is not successful, the B cell undergoes apoptosis (programmed cell death) - If the first attempt is successful, an intermediate Ig-like molecule containing the HC paired with a surrogate (temporary) LC: thought to be responsible for halting HC locus rearrangement and initiating LC locus rearrangement - there is sequential rearrangement of the LC loci until a functional locus is formed. It is estimated that only 1/3 of attempts to join V to J or D to J or V to DJ are successful

Noncompetitive Inhibition

These are PHARMACOLOGICAL ANTAGONISTS - agonist and antagonist both work on the same receptor - antagonist bind at allosteric site (agonist binds at orthosteric site) - antagonist can bind to receptor if the receptor is bound or not bound to the agonist

Competitive Inhibition

These are PHARMACOLOGICAL ANTAGONISTS - agonist and antagonist both work on the same receptor - both bind at orthosteric (active) site, compete for same site, if antagonist is bound, agonist cannot bind

Direct Adrenergic Receptor Agonists Overview

Think: 1. Location 2. Selectivity Remember that lose dose EPI is more useful that lose dose norepinephrine b/c don't get baroreceptor reflex from sudden increase in TPR (leading to increase in diastolic pressure)

Acute Inflammation: Necrotizing Bronchopneumonia

This necrotizing bronchopneumonia has numerous areas of raised, lighter tan appearance which are the areas containing the extensive neutrophilic infiltrates and tissue destruction. Necrotizing pattern of inflammation due to continued acute inflammation --> abcess formation Could develop into an abcess - collection of neutrophils (pus) that the body starts to wall off, formation of granulation tissue around neutrophils - Complication of acute inflammation

Catecholamine Synthesis and its Regulation

Tight regulation of rate limiting enzyme: Tyrosine Hydroxylase (TH): - rate-limiting enzyme in synthesis of norepinephrine (NE) and dopamine (DA). - requires a co-factor: tetrahydrobiopterin (BH4) may be actual overall rate-liming factor in synthesis (this is because tyrosine, TH substrate, is usually high enough to saturate the enzyme, but the co-factor may not be Regulation Mechanisms of TH 1. Phosphorylation of enzyme increases TH activity - phosphorylation by PKA, PKC and Calcium-Calmodulin kinases increase TH affinity for co-factor tetrahydrobiopterin (BH4) 2. End-product feedback inhibition by free intraneuronal NE or DA decreases activity of TH by competing with BH4 cofactor - this co-factor may be the limiting factor in synthesis not just the enzyme 3. Amount of TH can be increased by gene transcription. - Under some pathological conditions - for example, in heart failure (make more NE, EPI for heart contractility)

Features/Components of the Immune System

Tightly regulated system Integrated with other body systems Based on receptor-ligand interactions by changing affinity and/or concentration of either or both Leukocytes: initiating and effecting immunity Antibodies: bind to antigens and clear them Cytokines (IL): instructional molecules Chemokines: control cell migration Cell adhesion molecules (CAMs): form a synapse between cells, ICAMS, integrins, cadherins, lectins Transcription Factors/Master Regulators: determine cell phenotype - Many cells alter phenotype due to cytokine actions

Healing/Repair Definition

Tissue response to a wound, inflammatory process, or cellular necrosis Consists of a fibroproliferative response that acts as a patch - consists of a combination of regeneration and scar formation Involves new vessel formation and fibroblasts Variable depending on type of injury, tissue involved, extent and duration of injurious stimulus. Several factors associated with healing and repair: - Cell Proliferation - Regeneration - Extracellular Matrix - Repair - Wound Healing - Fibrosis

Examples of P450-mediated Drug-Drug Interactions or Genomic Based PK Changes

Tizanidine-Fluvoxamine Interaction - Tizanidine is a substrate of CYP1A2 - Fluvoxamine is a potent inhibitor of P450 isozyme - Interaction results in 12x increase in Cmax of Tizanidine and 33-fold increase in AUC - tizanidine cannot be metabolized as efficiently w/inhibitor present leading to increase in concentration and pharmacological effects - Interaction results also in pharmacodynamic effects (Decrease heart rate, decreased blood pressure, and impaired cognitive function). St. John's wort - Indinavir Interaction - St. John's wort (CYP3A inducer) significantly reduces exposure to indinavir (CYP3A substrate) - induces CYP3A resulting in increased metabolism of indinavir decreasing concentration and pharmacological effects CYP2D6 and Codeine - O-Demethylation of codeine to morphine via CYP2D6 is required for opioid activity - Analgesic Effect of codeine decreased in CYP2D6 poor metabolizers (PMs) or after inhibition of CYP2D6 - Life threatening codeine intoxication in patient with ultra-rapid CYP2D6 metabolism

Drug Transporters Affect on Pharmacokinetics

Transporters can have effects on pharmacokinetics of a drug (or endogenous substrate). - Transport of drugs and others substances in and out of cells - May directly control absorption, distribution, and elimination - May work in concert with metabolizing enzymes - May be modulated by drugs resulting in drug interactions Transporters known to interact with drugs in clinical use: - Breast cancer resistance protein (BCRP) - Organic anion transporter 1/3 (OAT1/OAT3) - Multidrug and toxin extrusion (MATE) proteins - Organic cation transporter 2 (OCT2) - Organic anion transporting polypeptide 1B1/1B3 (OATP1B1/OATP1B3) --- Example of clinically relevant drug interaction with rosuvastatin (substrate) and cyclosporine (inhibitor) --- Prescribing information states that rosuvastatin dose should not exceed 5 mg daily when given with cyclosporine (vs usual starting dose of 10-20 mg daily) because of risk of myopathy with increased plasma concentration of rosuvastatin caused by drug interaction

Tumor Clonality

Tumors are monoclonal (derived from a single precursor cells) However, still show tumor heterogeneity - tumor cell variants arise as mass expands

Acetylcholineesterase (AChE)

Two Types: 1. Specific for acetylcholine at the synapse (RBC and placenta) --> only breaks down ACh 2. Nonspecific one circulating in the blood that is a non specific esterase that will cleave any ester - plasma cholinesterase (pseudocholinesterase) MOA - Diagram

Physiological Antagonists

Two drugs that bind to two different receptors that have opposite physiological responses? Example - agonist at b-adrenergic receptor that increases heart rate (NE + bAR <--> increase HR) - agonist at muscarinic cholinergic receptor that decreases heart rate (ACh + mAChR <--> decrease HR)

Light Chain Isotypes

Two isotypes of LC: - kappa - lambda Each antibody has either two identical kappa or two identical lambda LC The identity of the LC as either kappa or lambda is determined by the aa sequence of the constant region In humans: - ~60% of antibodies contain kappa LC - ~40% contain lambda LC If we look more closely at lambda LC, we find that there are 4 slightly different constant region sequences forming four subclasses of lambda LC.

Vascular Events in Acute Inflammation

Two major changes occur: - vasodilation (heat, redness) - increased permeability (swelling) These changes are designed to move plasma proteins and inflammatory cells out of circulation and into the site of injury. Vasodilation: - transient period of vasoconstriction - vessel then dilates to allow more blood and blood components to get to the site of injury. - First in arterioles, then in capillaries. - cause of a warm and red area in case of subcutaneous or superficial injury. - Induced by several mediators including histamine and nitric oxide that act on the vascular smooth muscle. Increased permeability: - The normally intact endothelium becomes leaky during acute inflammation to allow for various proteins and cells to escape into injured tissue. - results in edema - Immediate transient response refers to formation of endothelial gaps in venules, one of the first events to occur and lasts between 15 and 30 minutes. - may be direct endothelial damage and injury that allows for increased permeability. - Delayed prolonged leakage occurs with some types of injury and is another mechanism of permeability beginning after 2 hours. - Neutrophils can release several toxic oxygen species and proteolytic enzymes that cause endothelial detachment. Summary: - Transient response mediated by histamine and leukotrienes (released from cells at site of infection/trauma causing endothelial cell activation) - Delayed response starting about 2 hours and lasting about 12 hours mediated by kinins and complement (released from complement and effector cells that have migrated to site of infection to recruit more inflammatory cells) - Delayed prolonged responses typically occurring after a burn (thermal injury).

Allotypes Significance

Type of immune response can occur due to: - exposure to different allelic products after transfusion - exposure of mother to fetal immunoglobulins during pregnancy - exposure to a therapeutic humanized antibody For example: - exposure to Ig from another individual can occur during pregnancy when mom is exposed to immunoglobulins from her fetus - In the family example shown, the father carries the Km(1) allele which the mother does not share. If this allele is passed on to one of the offspring, the mother while pregnant may be exposed to immunoglobulins made by the fetus possessing Km(1) encoded light chains stimulating the mother to produce alloantibodies to Km(1) - could have consequences in subsequent pregnancies if the antibodies pass the placenta **Note: "alloantibodies" --> antibodies against immunoglobulin components that differ among members of a species

Reversible Cell Injury

Type of injury that if the damaging stimulus is removed, the cell will return to its normal state Characterized by: - decreased oxidative phosphorylation - decreased ATP - cell swelling: membrane becomes damaged and leaky with influx of water Light microscopic - Cellular swelling - Fatty change Electron microscopic - Membrane blebbing - Loosening of intercellular bridges - Loss of microvilli - Mitochondrial and endoplasmic reticulum swelling - Myelin figures

Multiple Compartments Model

With IV administration there is often visible a very rapid, distribution, phase where the concentration drops very quickly, followed by the elimination phase shown here alpha-distribution beta-elimination

Drugs that increase catecholamine release

Tyramine Amphetamine Ephedrine (Ephedra) Pseudoephedrine

MAO Inhibitors (MAOI) Interactions can be Problematic

Tyramine Interactions: - Tyramine is all around and in us - in many foods we eat (Cheese, yogurt, other fermented foods and red wines) - forms from normal bacterial decarboxylation of tyrosine in our GI system. - So, why doesn't it affect our SNS? Rich supply of MAO in gut and liver prevents its escape to the general circulation - But when MAO is inhibited tyramine can be a problem - Generalized inhibition of MAO allows tyramine (from diet and from bacteria in gut) to escape degradation in gut and liver and circulate in the blood to enter peripheral NE axons - Because MAOIs markedly increase concentration of NE in cytoplasm of SNS axons, the effects of tyramine, as well as indirectly-acting agonists (found in many OTC cold preps and herbals that release NE e.g., pseudoephedrine and others), can be dangerously exaggerated, with the risk of hypertensive crisis, stroke or MI. - Thus, patients using MAOIs must restrict their dietary intake of tyramine-containing foods and drugs that can increase NE release Drug Interactions between MAOI and other drugs - can be problematic—even fatal 1. Meperidine (Demerol) known interactions with MAOIs, but caution with all opiates 2. Indirect-acting stimulants, antidepressants, dextromethorphan (in most cough meds), OTC decongestants - Both can interact with MAOIs and therefore should not be given to someone who has taken an MAOI within 2 weeks because of possibility of causing a constellation of life-threatening effects known as the "serotonin syndrome". Serotonin Syndrome - Usually associated with several drugs acting together to increase serotonin (e.g., serotonin uptake inhibitors and MAOI) - Increased BP, HR, temperature, tremor, hyperreflexia, agitation, confusion - can be fatal. Because of these potential interactions, MAOIs are usually not a first line or popular treatment for depression, but one is used as an adjunct for Parkinson's disease

Adrenergic Nerve Terminal: Critical Steps in Noradrenergic Neurotransmission

Tyrosine Hydroxylase is highly regulated - negative feedback inhibition from end products - phosphorylation increases activity Note: most of the steps in synthesis take place in the cytoplasm - Exception: Dopamine is transported into storage vesicle via the VMAT and DA --> NE takes place in the storage vesicle What about NE --> Epinephrine in the adrenal gland? - Requires PNMT enzyme and SAM as methyl donor, both of which are in the cytoplasm - NE leaks out of vesicle and converted to EPI via PNMT in cytosol

Synthesis of Catecholamines

Tyrosine hydroxylase is the rate-limiting step. - metyrosine, inhibits TH decreasing synthesis of DA, NE, EPI. L-amino acid decarboxylase (LAAD) is not specific. - It will metabolize other endogenous compounds and some drugs: (conversion of 5-OH-tryptophan to 5-OH-tryptamine by LAAD) - LAAD can be inhibited in the periphery by carbidopa, which does not cross the blood brain barrier. - Carbidopa is given with L-dopa to treat Parkinson's Disease to prevent the conversion of L-dopa to dopamine in the periphery.

Fat Embolus

Uncommon Involves fat (normal component of bone marrow) and often other elements of the bone marrow that become dislodged during: - severe trauma (several fractures) or burns - orthopedic surgery, - rigorous CPR (with fracture of sternum) May or may not cause symptoms. Fat embolism 'syndrome' may result in death: - Pulmonary insufficiency - Neurologic symptoms (irritability, confusion, seizures) - Anemia (RBCs aggregate and hemolyze) - Thrombocytopenia (platelets attach to fat, and are removed, resulting in low platelet count) - Pathogenesis involves both mechanical and biochemical injury and the syndrome may have an element of DIC

Amniotic Fluid Embolus

Uncommon Complication of normal pregnancy during labor or the immediate post-partum period Result of infusion of amniotic fluid (and some fetal tissue such as squames from skin or hairs) into maternal circulation via tears in fetal membranes or rupture of uterine veins Sudden onset of dypsnea, confusion, seizure, hypotension High mortality and often associated with DIC

Stages of Shock

Unless the insult is rapidly fatal, there are three general phases of shock: 1. Nonprogressive: (reflex) - compensatory mechanisms are activated to maintain perfusion of vital organs. Clinical Correlate: - Tachycardia - Peripheral vasoconstriction: coolness, 'clamminess', pallor - Renal conservation of fluid (lack of urination) 2. Progressive: - Characterized by tissue hypoperfusion, metabolic abnormalities (acidosis), widespread tissue hypoxia Systemic acidosis blunts vasomotor response: - Arteriolar dilation and pooling of peripheral blood Clinical correlate: - Lab values associated with acidosis - Decreased urine output and mental confusion (build of urea, toxic metabolites) 3. Irreversible: - Tissue and cellular injuries are non-recoverable even if hemodynamic defects are corrected. Clinical correlate: - Lab values associated with renal failure (increased blood urea nitrate/BUN and increased creatinine), little or no urine output - If sepsis: increased WBC count, inflammatory markers - Potential disseminated intravascular coagulation (DIC) and death Hypotensive and cardiogenic shock - Weak, rapid pulse - Tachypnea - cool, clammy cyanotic skin Septic shock - Prognosis varies with age of patient and type of shock - Prognosis is worse for older patients with co-morbidities and for cardiogenic and septic shock.

Monoclonal Antibodies as Tools

With the advent of recombinant DNA technology, other ways to generate or alter monoclonal antibodies have been developed These methods are targeted at making the monoclonal antibodies from a mouse more human-like in order to lessen any immune responses to antibody therapies and to improve their properties. Some therapies use antibodies with two different Fab arms to, for example, target a tumor cell for killing by linking the tumor cell to an immune cell.

Effect of Multiple Doses

Up to now: inject drug => see what happens to concentration. Typically, drugs are given chronically. What happens to plasma concentration when the drug is given at frequent intervals? Ex: If you give 2 grams of drug/day once a day of a drug that has a t1/2 of 1 day * Mean steady state levels (>90%) are reached after approx. 4 half lives (= 4 x t1/2) * Steady State Concentration (Css): Amount out = Amount in * What if the patient can't wait 4 days for levels to come up to the target plasma concentration (which is in the therapeutic range)? - What would happen if the first dose on the figure above was doubled? - What is a loading dose? - Should it always be given in a single administration (no). * What if the amplitude is too large resulting in peak concentrations too high and trough concentrations too low? i.e. what if the toxic dose is about 3.5 and mec is about 2.5

Immunotherapy

Vaccines Adoptive Transfer of cells: T-cells, DCs Adoptive Transfer of Igs, cytokines

Pathologic Findings of Edema

Variety of clinical, gross, microscopic findings associated with edema depending on organ system or tissue involved. Lungs Clinically pulmonary edema is common Increased hydrostatic pressure - Congestive heart failure (CHF) left sided - Pulmonary vein obstruction (enlarged lymph nodes or tumor) Microvascular injury - Infection - Aspiration (gastric contents) - Radiation Brain Edema in the brain may be localized to a specific area or it may be diffuse Mechanisms include: - Hypertension - Obstruction - Severe trauma - Metabolic (hyponatremia) Complications 1. Lower extremity edema (subcutaneous) - Difficulty mobilizing which can lead to other problems - Impaired wound healing 2. Pulmonary edema - Shortness of breath - Risk of infection - Chronic cough 3. Cirrhosis leading to ascites - Shortness of breath (abdomen impinges on the thoracic cavity) - Abdominal discomfort - Decreased mobility - Risk of infection 4. CNS edema - Midline shift or herniation

Acute Inflammation: Vasculitis

Vasculitis shown here demonstrates the destruction that can accompany the acute inflammatory process and the interplay with the coagulation mechanism The arterial wall is undergoing necrosis, and there is thrombus formation in the lumen Purple and black in inflammatory cells (neutrophils) Vasculitis (inflammation of BVs) - typically leads to a rash in the skin

Volume of Distribution

Vd is the APPARENT volume that the administered drug is dissolved in Original (initial) concentration (Co) in plasma = 0.2 mg/ml Dose (D) of drug given = 1000 mg Apparent volume of distribution of the drug would be: - Vd = D/Co = (1000 mg)/(0.2 mg/ml) = 5000 ml = 5 liters Why is the volume only apparent? - bucket analogy: What if you dissolved 10 grams of a drug in a bucket full of water, and the volume was unknown. - Then you assay the concentration of the drug and find it to be 1 gram/Liter - What is the volume of the bucket? --> 10 L - What if 9.9 grams of your 10 grams stuck to the sides of the bucket (and you didn't know it) and you measure the concentration (of free drug) to be 0.01 grams/liter. - What is the volume of the bucket? --> 1000 L - analogous to a drug that is sequestered in some tissue store (e.g. fat) causing concentration in plasma to be very low --> so the Vd is very large. If there are absorption and/or distribution phases Co is determined by extrapolating back to the y-axis. Drug can be found in places other than blood, e.g. fat, brain, which lowers the blood concentration - If the drug never leaves the blood --> Vd will be a few (4-8) liters - If the drug leaves the blood through gaps in capillaries but can't pass through membranes and thus is found in interstitial fluid --> Vd will be about 15 liters. - If the drug passes through membranes and is highly localized (>95%) to, for example, fat the Vd may be many (>100) liters - Thus, Vd may have no physical meaning. Things that can affect Vd: - Renal failure and liver failure (alter fluid retention and protein binding) - Dehydration Knowing Vd allows you to calculate a LOADING DOSE - how much drug do you need to fill up the bucket to achieve a target initial concentration of drug - D = Vd x Co --> What dose do I give to achieve target concentration

Thromboembolism: Pulmonary Embolus

Venous thrombus (originating in femoral vein most commonly) that potentially occludes small or large branches of pulmonary artery Very common entity that occurs in a variety of clinical settings in both men and women. Predisposing factors include: those associated with hypercoagulability and immobility (particularly post-operative period, long plane rides etc) Clinical Spectrum: - Small occlusions may be clinically silent - large ones may cause chest pain - An embolus at the bifurcation of the pulmonary artery (referred to as a saddle embolus) is fatal - blocks blood flow to both lungs

Neoplasia: Melanoma

Very large nodular melanoma excised from the back Such a lesion should have been excised long ago. Metastases are often present when the lesion is allowed to reach this size.

Healing Response: Healing around Abscess

Wall of an abscess that is organizing has granulation tissue (left) - Formation of healing around the abcess (walling off) Purulent exudate with some hemorrhage is seen at the right in the abscess center Macrophages typically signal the healing response - response fibroblast stimulating cytokines) - macrophages guide the process Granulation tissue - fibroblasts producing collagen - repair by scar and endothelial cells b/c need a vascular supply via angiogenesis - vessels are often leaky while developing

Chemical Antagonism

What about drugs that don't bind to a receptor at all but instead, bind to or interfere with another drug? Example: - heavy metals: Pb++ or Cd++ or Hg++ are all toxic and accumulate in the liver - How is heavy metal poisoning treated? - common approach is to use a chelating agent - negative charges on EDTA clasp the heavy metal like a crab claw (chela) - allows the heavy metal to be excreted

Pharmacokinetics

What the body does to the drug Drugs act via receptors to cause a response = Pharmacodynamics To get to its receptor the drug has to: - enter the bloodstream (absorption) - be carried to its site of action (distribution) In the meantime the body is: - metabolizing the drug - excreting the drug Pharmacokinetics is the sum of ADME - Absorption - Distribution - Metabolism - Excretion relationship between drug dose, concentration in blood, and time ADME begins as soon as the drug is administered

Pharmacodynamics

What the drug does to the body Combination of drug with a receptor produces a specific response. - Drug + Receptor <--> DrugReceptor => Response - D + R <--> DR => Response - Similar to enzyme kinetics: S + E <--> ES => P + E Drug-receptor interactions are analogous to enzyme~substrate interactions - And similar principles apply (e.g. Michelis-Menten) - V = Vmax (S) / (S) + Km Most drugs combine with specific sites on macromolecules (e.g. cell membrane components, enzymes, proteins) by precise physiochemical and steric interactions between specific chemical groups on the drug and receptor - Lipophilic, Hydrophilic, Ionic, Hydrogen bonds, Steric (stereospecificity) effects, Electronic effects, pK effects Endogenous ligands (e.g. enkephalin versus morphine) - Most receptors that drugs interact with don't exist because of the drugs - usually endogenous ligands. - endorphins & enkephalins vs morphine act at opiate receptors

IgE and Allergy

When exposed to antigen/allergen (like ragweed pollen or bee venom) and cross-linked, IgE bound to FcR sends activation signals causing mast cells and basophils to degranulate The release of histamine causes immediate hypersensitivity reactions (responsible for symptoms of hay fever, hives, anaphylactic shock).

Isotypes Significance

Why is this type of response important in medicine? - Antibodies generated in other species are used in immunotherapies For example - horse anti-snake venom antibodies have been used to treat snake-bite victims - monoclonal antibodies synthesized by a mouse immunized with a human tumor have been used in cancer immunotherapy Response in patients given these therapies targets regions of the antibody that are foreign i.e., that are species specific (LC, HC constant regions) This immune response, causing destruction of the antibodies used in therapy, will reduce the efficacy of the therapy.

Neoplasia: Heptocellular Carcinoma

Worldwide, viral hepatitis may be the most common etiology In the U.S., most cases are associated with chronic alcoholism Neoplasm is large and bulky and has a greenish cast because it contains bile To the right of the main mass are smaller satellite nodules. Malignant cancer arising from hepatic cells = hepatocellular carcinoma (epithelial origin) Associated with cirrhosis (HCV, virus, chronic alchol uses, fatty liver) - associated with chronic inflammation

Complications of Cutaneous Wound Healing

Wound dehiscence: - rupture of the wound and occurs most commonly after abdominal surgery often due to increased pressure or mechanical stress on the wound Ulceration: - sloughing of the superficial epithelial layer - often secondary to inadequate vascularization - will see this in diabetic patients' lower extremity wounds that are difficult to heal (poor vascularization) Keloid: - Excessive scar formation referred to as a hypertrophic scar - fibrosis extends beyond the borders of original wound it is referred to as a keloid - Certain persons are predisposed to this Contractures: - wound contraction can be a normal part of healing - if it becomes excessive, a deformity can result leading to a functional deficit

Actue Inflammation: Meningitis

Yellow-tan exudate of acute bacterial meningitis seen here obscures the sulci.

Muscarinic Antagonists

also known as anti-muscarinic or anti-cholinergic (not a great word) Atropa (atropine) Belladona --> weed - competitive antagonists at muscarinic sites Atropine - tertiary N (no charge) --> can be taken orally, absorbed b/c not carry a positive charge Homatropine - eye drops - dilate the pupils --> eye doctor to look at retina - used for optomological examination quaternary compounds (cannot be taken orally) - given by inhaler - treats asthmatics - cause bronchodilation Tolterodine - urinary incontinence w/age in women - give the last antimuscarinic causes bladder distention (relaxation) --> dont pee! SIDE EFFECTS!!!! Hyperhydrosis treatment - new anti-sweating medication -nGlycopyrronium (Qbrexza) - Once Daily Topical Treatment-Towelette - Anticholinergic - Side Effects: Dry Mouth, Blurred Vision, Urinary Retention Be aware of antimuscarinic side effects in common medications - Benadryl

Receptor Regulation

chronic drug administration can alter the responsiveness of the receptors 1. Disuse supersensitivity - denervation or chronic antagonist administration can lead to an increase in response to an agonist (in this case because receptor numbers increase) - Problem: A patient who has been taking a B-blocker (e.g. propranolol) chronically for years to control hypertension, goes on vacation and runs out of pills (more B-receptors, unregulated expression due to chronic antagonism) 2. Desensitization or Down-Regulation - Loss of receptor response or decrease in receptor number due to chronic administration of a receptor agonist - Problem: A patient, self-medicating with an inhaler (b-adrenergic receptor agonist e.g. albuterol) for treatment of asthma, keeps increasing the dose by inhaling more frequently than recommended - But it is not always the receptor that changes: - Problem: Normally, stimulation of opiate receptor decreases adenylyl cyclase activity => decrease in cAMP production - Chronic opiates lead to compensatory and constitutive increase in adenylyl cyclase activity and therefore an increase in cAMP. - Thus, the patient NEEDS opiates to decrease cAMP to normal (addiction & dependence). Bottom line: - Chronic administration of drugs can cause a change in the responsiveness of the system. - Rapid withdrawal of drug can precipitate negative responses --> often on package inserts.

Effects of Autonomic Ganglionic Blockadge

shot gun approach (for hypertensive emergency)

Fibrinoid necrosis

vasculitis?!