Cellular & Molecular Basis of Medicine, Exam 4

Cytokines that stimulate hematopoiesis: Therapeutic uses

CSFs and other stimulators of hematopoiesis: Therapeutic uses ∙Filgrastrim (recombinant human G-CSF) →Used in patients receiving myelosuppressive anti-cancer regimens →→→Increases neutrophil recovery →→→Reduces infection →Side effects →→→Splenic rupture (b/c you are giving growth factor and spleen serves as location for cell division, so you can bust capsule) →→→Allergic rxns ∙Sargramostim (recombinant human GM-CSF) →Usages: to achieve neutrophil recovery and reduce infection →→→Bone marrow transplantation →→→Autologous or allogenic →→→AML →Side effects →→→Bone pain →→→Fever →→→Fluid retention ∙Erythropoietin →Usages →→→Anemia →Side effects include →→→HTN →→→HA →→→Seizures →→→Thrombotic events

Immune complex-mediated disease

Can be either systemic or localized Systemic ∙Prototype (serum sickness) now infrequent, but used to be a common sequella of treatment of patients w/ foreign sera ∙When occurs now, usually associated w/ immune complexes that are formed in the circulation, but are deposited in many organs Localized ∙Localized to particular organs (kidney, joint, small blood vessels of skin)

Therapeutic Uses of IFNs

Cancer ∙Malignant melanoma ∙Renal cell carcinoma ∙Chronic myelogenous leukemia Viral infection ∙Hep C (in conjunction w/ antiviral drug ribavirin) Relapsing-remitting MS

Latency in Herpes Simplex Virus (HSV)

Capsid travels up the axon and to the nucleus ∙There can be a low level of replication and the genome is maintained, but nonintegrated Expression of LATS (latency associated transcripts) from a single promoter occurs during latency, these are involved in maintaining latency in viral neurons because the immune system doesn't see viral protein ∙LATs do not encode a viral protein but instead encode a regulatory microRNA (miRNA) ∙miRNAs inhibit translation of mRNA ∙LATS may affect signaling pathways to block apoptosis Latency characteristics ∙Little or no viral proteins are expressed ∙T cells cannot detect infected cells and remove them ∙Latency in VZV occurs in neurons like HSV (several viral RNAs and proteins are in latently infected cells) Herpes Simplex reactivation ∙Triggers: →UV radiation, fever, emotional or physical stress, menstruation, foods (spicy, acidic, allergy), immunosuppression (HIV or chemo) ∙Neuronal changes leading to reactivation are unknown, but low levels of productive infection must occur in neurons ∙Infectious virus travels down the axon to the site of initial infection ∙Triggers a productive infection in nearby permissive cells ∙Remember, already have a memory response to virus so will be cleared more quickly as a result of reactivation than in a productive infection ∙HSV results in cold stores or genital lesions →There are many episodes of this and the probability of getting one decreases with age →The reactivation occurs at the site of primary infection because during reactivation limited virus is made ∙In VZV, reactivation results in Zoster (also called shingles) →There is usually only one episode of this and the probability of getting zoster increases with age →The reactivation occurs where the virus enters the neuron

Assembly and release

Capsids self-assemble ∙Package genome and core enzymes Naked virions are released upon cell lysis Enveloped viruses bud ∙Matrix proteins determine the site of budding →Plasma membrane, can but into the ER, golgi, nuclear membranes; released via exocytosis ∙Act as a bridge between nucleocapsid and surface glycoproteins →Budding of enveloped viruses from the plasma membrane ∙Release of naked cells via cell lysis →DNA virus passes through a nuclear pore and is released upon the lysis of the cell

Inflammatory phase of wound healing

Caused by PMN secretions ∙Increase vascular permeability →This produce redness, swelling, pain, heat and stiffness ∙PMNs protect against bacterial infection Circulating monos recruited become tissue macrophages ∙Macrophages phagocytose BacT and destroyed tissues ∙Produce cytokines and growth factors ∙Help dissolve clot ∙Recruit fibroblasts and stimulate them to produce a protein scaffold, temporary ECM called granulation tissue Steps ∙Margination - opening b/w epithelial cells ∙Diapedesis - squeezing of PMNs b/w epithelial cells ∙Chemotaxis ∙Phagocytosis

Mechanism of action of antifungals

Cell wall is a target, b/c mammals do not have cell walls Ergosterol of cell membrane is a target, b/c mammalian cells have cholesterol instead

Galectins

Cells attach through CHO recognition systems: E.g., glycans on cell surfaces and molecules in ECM Lectins are CHO recognition molecules ∙Galectins contain Carbohydrate Recognition Domain (130AA) ∙Can be expressed intra- and extra-cellularly ∙Different galectins recognize different sugars = gives them specificity ∙Subunits can combine → multivalency, for several molecules →Ex: Galectin can recognize glycan in ECM and glycoprotein on cell receptors →This can prevent endocytosis of cell surface molecules, prolonging their activity

Proliferation phase

Cells involved: ∙Fibroblasts, EC, epithelial cells (keratinocytes), mesenchymal stromal cells (MSC) *Extra-cellular matrix (ECM) biosynthesis (granulation tissue → temporary)* ∙Fibroblasts produce a scaffolding for recruited cells and collagen deposition enabling cell attachment ∙Fibroblasts → myofibroblasts →Actually change their nature →Contain actin that pulls the wound edges together and produce scar tissue from the evolving granulation tissue →Scar tissue is useful b/c it actually pulls everything together and forms barrier from outside environment Epithelialization ∙Keratinocyte recruitment involves their detachment, migration, proliferation in situ, differentiation to produce normal stratified epithelium ∙Collagen (type III>I) creates granulation tissue that becomes a scar Angiogenesis ∙To restore blood flow and oxygen to tissue ∙Endos (EC) are attracted by cell secretions ∙Proliferate and form many tubes that connect with local blood supply

Systemic candidiasis: Predisposing factors

Cellular immunodeficiency ∙AIDS, chronic granulomatous disease etc. ∙Neutropenic patients often given fluconazole prophylaxis ∙C. glabrata is being seen more often in ICUs because of widespread fluconazole use Immunosuppressive treatment ∙Bone marrow transplant patients, leukemia patients Patients with indwelling catheters, intravenous lines, or prosthetic devices Patients receiving corticosteroid treatment Most important risk factor for invasive candidiasis is a prolonged stay in the ICU

IL-1

Cellular sources ∙Macrophages ∙Endothelial cells ∙Some epithelial cells Targets and biologic effects ∙Endothelial cells →Activation →Inflammation →Coagulation ∙Hypothalamus - fever

IL-6

Cellular sources ∙Macrophages ∙Endothelial cells ∙T cells Targets and biologic effects ∙Liver: synthesis of acute phase reactants ∙B cells: proliferation of antibody-producing cells

Epstein-Barr Virus

Characteristics ∙Cell tropism determined by presence of EBV receptor in cells ∙Viral receptors: CR2 or CD21 (receptor for C3d component of C) ∙Expressed on B cells (productive, immortalizing or latent infection) and epithelial cells (productive infection) of the oropharynx & nasopharynx ∙MHC Class II molecules are used as co receptors Proteins are associated with productive infection ∙Can test for specific antibody if you suspect someone has mono ∙Serologically defined markers: →Early antigen (EA) →Viral capsid antigen (VCA) (main one) →Membrane antigen (MA) ∙Zebra (a transcription activator protein): activates immediate early genes, sends virus through the lytic cycle →Not expressed in latent or immortalizing infections Non-productive infection of B cells ∙Some immediate early genes are expressed →Epstein Barr nuclear antigens (EBNA) →Latent proteins (LP) →Latent membrane proteins 1 and 2 (LMP) →→→These have oncogene activity →2 small Epstein Barr encoded RNA molecules (EBER) ∙Non-productive infections include latency or immortalization Latent infection ∙Non-integrated, plasmid-like genome replicates during cell division (in latency: EBNA-1 is expressed as cell division and this allows the viral genome to remain within the cell) ∙Occurs in memory B cells, in the presence of competent T cells →T cells eliminate EBV-activated B cells, so only latent ones not cleared ∙Low level of viral protein minimizes triggering of the immune system Immortalization of B cells ∙Cells are stimulated to divide and secrete antibody and get polyclonal activation and heterophile antibodies →IgM recognizes Paul-Bunnell antigen on sheep, horse, and bovine erythrocytes →Heterophile antibodies can cause rbcs from these animals to agglutinate ∙B cell mitogen: →Stimulates growth of B cells in vivo →Prevents apoptosis →B cells can become immortalized in tissue culture if no T cells to eliminate activated cells →EBNAs and LPs are involved (DNA binding proteins) ∙EBV-activated B cells are eliminated by T cells →*Mononucleosis: Activation and proliferation of T cells* →→→Many T cells are present because they are responding to EBV infected B cells →→→Some T cells will become atypical lymphocytes →→→The presence of these is a test for mono →Acute HIV can also mimic mono Figure: ∙During productive infection, actively making viruses ∙After T cells clear immortalized B cells, memory cells will become latently infected (EBNA-1 is the only protein associated with this) ∙EBV is assoicated with some cancers as well

Human herpesvirus 6 & 7

Characteristics ∙Replicates in salivary glands and transmitted by saliva ∙Latency infects T cells and monocytes ∙Ubiquitous, primary infection occurs in children ∙First isolated in 1986 (6) and 1990 (7) Clinical disease: Roseola infantum (sixth disease): ∙Will get a high fever and then fever drops and rash appears suddenly ∙Usually occurs in young infant ∙Associated with exanthem subitum ∙May contribute to morbidity in AIDS and following transplants (but there is no clear association)

Infectious Mononucleosis

Characteristics ∙Usually occurs in 10-20 year olds and young children have no symptoms because of a less active immune response ∙T cell response to EBV infected B cells →T cell activation leads to malaise and Downey cells ∙B cell proliferation leads to heterophile antibody (IgM that can agglutinate rbcs) ∙Increase in mononuclear cells (60-70% of wbc count) and atypical T cells called Downy Cells are present (30% of lymphocytes) Clinical Infection of Mononucleosis ∙Incubation: 30-50 days ∙Symptoms: fatigue, low grade fever (may last months), pharyngitis, headache, enlarged lymph nodes and spleen, possibly sign of hepatitis, and rash in patients treated who were given amoxicillin for strep throat ∙Most symptoms last 2-4 weeks ∙Two tests done early on to determine if present or past infection (IgG vs IgM) →The nuclear antigen doesn't get exposed to immune system →In past exposure, there is a presence of IgG and antibody to EBNA →In present illness, see IgM Reactivation ∙Virus latency infects memory B cells →If these are reactivated, can lead to reactivation infection ∙Activation of latently infected memory B cells allows for transcription of ZEBRA →ZEBRA turns on expression of immediate early genes which initiates a productive infection ∙Common in tonsils and oropharynx (virus is shed in the saliva) ∙Often asymptomatic Diagnosis of mononucleosis ∙Increase in circulating WBC's like Downey cells (large, atypical T cells) ∙Detect heterophile antibody using Monospot test (and maybe EIA) and these antibodies can be detected for several months ∙Nucleic acid hybridization ∙Immunoflourescent detection of viral antigens ∙Serology oF EBV Serology of EBV ∙Acute infection can be proven by: →IgM to VCA (viral capsid antigen) →The presence of the VCA antibody and not the EBNA antibody (early acute phase) →The Early acute antibody (after detection of VCA antibody) →Alpha-EBNA antibody requires lysis of infected cells and this occurs as T cells clear the infection →Also associated with convalescence/resolution of infection

Human herpesvirus 8 (HHV 8)

Characteristics: ∙First recognized in 1994 ∙Transmitted in saliva or by sexual practices ∙A new herpes virus may have been present in Kaposi Sarcoma tumor cells (KSHV) ∙Present in certain areas like Italy, Greece, and Africa and also in AIDS patients ∙Infects B cells and endothelium derives spindle cells

Parasite Identification

Charcot-Leyden crystals = the by-products of eosinophil break-down and can be seen in sputum, stool, urine, etc. ∙Are dipyramidal and hexagonal ∙Usually evident w/ eosinophil breakdown and tissue damage from tissue-invading parasites ∙Can be detected in sputum of patients w/ ascariasis, ancylostomiasis, stool samples in trichuriasis, and in CSF in Angistrongylus species Eosinophilia - generally caused by a helminth penetrating the mucous membrane during migration

Second wave of mediators (synthesized de novo)

Chemokines Cytokines: IL-4, TNF-α Prostaglandin D2 ∙Most abundant mediator produced in mast cells by the cyclooxygenase pathway ∙Promotes dilation and increased vascular permeability: mucus secretion ∙Intense bronchospasm ∙Chemoattractant for neutrophils Leukotrienes C4 and D4 are most potent and spasmogenic agents known ∙*Activities similar to histamine, only 100-1,000x more potent* ∙Inflammation ∙Smooth muscle contraction →Airway constriction ∙Mucus secretion Leukotriene B4: highly chemotactic for neutrophils, eosinophils and monocytes

More cytokine cross-talk

Chemotaxis ∙PDGF, EGF, FGF, TGF-b, TNF-a Inflammation ∙PDGF, TGF-b, FGF, TNF-a, IL-1 Proliferation ∙PDGF, FGF, IGF, KGF Re-epithelialization ∙TGF-a, EGF, KGF, IGF Angiogenesis ∙VEGF, FGF, Angiogenin, TGF-a, b

Pathogen spread in the host

Circulating fluids - lymph and blood Intracellular organisms may spread via WBCs (monocytes in particular, but also neutrophils) ∙In addition, lymphocytes could be directly infected Direct spread - open orifice and along skin ∙May utilize enzymatic mechanisms such as secretion of hyaluronidase, proteases, collagenases (MMPs), lipases, nucleases Image is listeria ∙Originally enters cell in vacuole, but breaks out ∙Will bind actin proteins in cells - actin helps motility of the organism, but it also hides organism →The actin does not allow our cells to use ubiquitination or lysosomes to eradicate this infection ∙Will be expelled from the cell from the submucosal area into the blood stream ∙Can develop meningitis from this →Even worse w/ pregnant mother - can get to fetus, lead to fetal death (or death of mother)

B cell production of IgE

Class switching favored by IL-4 IgE produced binds to FcRε on mast cells and other cells ∙Basophils, too Individual now considered sensitized

Dx of LD

Clinical ELISA, hemagglutination or IFA, followed by western blot if first test positive/equivocal ∙Tests are not useful in assessing treatment success or follow-up ∙The predictive value of test depends primarily on probability that patient has LD (Bayes' theorem) Important for clinicians to consider what evidence (both clinical and epidemiological) there is to "rule in" LD before serological tests are ordered to rule out Dx

DNA vs. RNA viruses

Clinical consequences of the type of genome ∙DNA viruses and retroviruses →Transformation; immortalization →Latent infections (DNA is "dormant" in the cell ∙RNA viruses →Variability leads to quasi-species →→→RNA polymerase makes a lot of mistakes and this leads to a higher incidence of infection →→→Examples: Hepatitis C, HIV (leads to difficulty in treatment)

Diagnosis of fungal infection

Clinical symptoms & detection of fungus in clinical specimen ∙Use features of organism (i.e. hyphae, pseudohyphae) to help identify Confirm by culture ∙Pathogens are often slow growing (days to weeks) ∙Need to see type of conidia and/or hyphae produced ∙Lactophenol cotton blue Skin tests indicate past or present infection ∙Fungal antigens may induce cross reactivity with other fungi ∙Not diagnostic - only shows that pt has been exposed to that fungus at one point PCR ∙Not routinely used yet ∙Likely to be important for diagnosing mycoses in the future

Spore-Forming Anaerobes

Clostridia

Non-Spore Forming Gram (+) Bacteria

Colonize skin and mucosal surfaces Opportunisitic pathogens Endogenous infections Clinical samples contain aerobic and anaerobic bacteria (mixture) Grow slowly in lab

Clostridium botulinum

Commonly found in soil and water samples across the world *Heat-labile neurotoxin (zinc endopeptidase)* ∙Binds receptors on motor neurons ∙Remains at the neuromuscular junction ∙*Prevents release of acetylcholine at the neuromuscular junction ∙Prevents contractions, causing a flaccid paralysis* Foodborne botulism ∙Consumption of home-canned foods contaminated by C. botulinum spores ∙Consumption toxin-contaminated food is sufficient to cause disease; ingesting the organism is not necessary Infant botulism ∙Consumption of spores in honey ∙Ingestion of spore contaminated soil and dust (now most common source of exposure)

Mechanism of Diflunisal

Competitive inhibition of COX

Mechanism of ibuprofen

Competitive inhibition of COX

Mechanism of action of naproxen

Competitive inhibitor of cyclooxygenase Inhibits hydrolytic enzymes of lysosomal system Inhibits migration of PMN leukocytes

Mechanism of action of ketorolac

Completely absorbed following IM injection Very potent inhibitor of COX If you have intestinal surgery, they will not release you until they hear bowel sounds ∙Narcotics will also decrease motility of the GI tract ∙Ketorolac is a better choice in this scenario, b/c it does not affect GI motility

Pica

Compulsive ingestion of non-nutritive substances (ice, direct, wall paint, etc.)

Sulindac (Clinoril)

Congener of indomethacin A prodrug - sulfide metabolite is the active agent ∙b/c it's a prodrug, its less irritating to the gastric mucosa than indomethacin Still more irritating to the gastric mucosa than other NSAIDs Toxic effect similar to indomethacin

Conidia

Conidia = asexual spores Conidiophores support chains of conidia ∙Aspergillus Sporangium w/ sporangiospores ∙Mucormycetes Blastoconidia: budding yeast cell ∙Cryptococcus neoformans ∙Tissue form of Histoplasma capsulatum ∙Tissue form of Blastocytes dermatitidis Microconidia & macroconidia ∙Single- or multi-celled conidia ∙Morphology is used to speciate dermatophytes Arthroconidia: formed by fragmentation of hyphae ∙Infectious form of Coccidioides immitis Endospores: spores produced w/in a spherule ∙Tissue form of Coccidioides immitis

Vaccines against capsular antigens

Contain strain- and species-specific antigens ∙*Polysaccharides* →do not generate T dependent immunity, but the *aim of the vaccine is to induce complement-fixing, anti-capsule antibodies* Also determine pathogenicity ∙Block alternate pathway complement activation Aim of vaccine is to produce complement-fixing anti-capsular antibody Antibody response is usually T-independent ∙Babies don't make good T-independent immune responses →Particularly susceptible to infection by encapsulated bacteria ∙Polysaccharide is usually conjugated to a carrier protein Capsular vaccines ∙Streptococcus pneumoniae ∙Neisseria meningitidis ∙Hemophilus influenzae →Conjugated vaccine is effective in reducing incidence and severity of childhood meningitis and pneumonia Capsular vaccines: Conjugates ∙Conjugating the polysaccharide antigen to a protein carrier improves the vaccine ∙Why? →More chance of class switching from IgM to IgG →Higher antibody titers →Generation of memory (T-DEPENDENT RESPONSE AS WELL) →Longer lasting immunity →More effective in younger children

Taking over host cell

Control transcription ∙Make viral mRNAs Replicate genome Control protein synthesis so that the cell is making viral proteins

Controversy: Vaccines and Autism

Controversy: Vaccines and Autism Study in 1998 linked autism to MMR vaccine ∙Small sample size (12 children) ∙Study suggested that vaccine caused bowel problems →Impaired nutrient absorption lead to autism *Study retracted by Lancet, lead author found guilty of scientific misconduct, lost license to practice in UK* Newer studies: Study #1 ∙Cessation of thimerosal use in Denmark and Sweden in 1992 ∙Before and after comparison of the incidence or case numbers of autism ∙In both countries, autism increases throughout the years 1987-1999, contrary to the decrease in autism that would be expected after 1992 if thimerosal exposure was related to autism ∙American Journal of Preventive Medicine (Aug 2003; 25(2):101-6). Newer studies: Study #2 ∙Cases were children with a diagnosis of autism spectrum disorder according to DSM-IV criteria that were between the ages of 3-10 years of age in 1996 →there had been an assumption that age of vaccination had something to do with development of autism ∙Controls were matched 3:1 with cases based on school system, birth date and gender ∙The study found that the overall distribution of ages at MMR vaccination among children with autism was similar to that of matched control children ∙Pediatrics (Feb 2004; 113(2):259-66) Others as outlined in appended documents

Therapeutic options for chronic inflammation

Corticosteroids Non-steroidals and other anti-inflammatories

Q fever

Coxiella burnetii (rickettsia) remains viable in soil and milk for several months in a spore-like form ∙Strictly intracellular bacterium living inside phagolysosome of host monocyte/macrophage cells and is the most frequent organism in blood-culture-negative endocarditis ∙Maintained in ticks and other arthropods ∙BSL-3 pathogen Transmission - by inhalation, contact w/ infected blood/placenta of animal and ingestion ∙Tick bite may transmit ∙Incubation period is 1-3 weeks ∙Rural residents may be infected from trucks carrying cattle, sheep or contaminated straw, manure, or dust kicked up by vehicles ∙Laundry workers developed Q fever after handling contaminated laundry from research facility Dx: made by immunofluoresence Unique risk factor = kangaroo hunting Ideal BT agent b/c of its widespread availability, natural potential for aerosolized use, environmental stability, consistently causing disability, possibly manufacture on a large scale, stability under production, storage and transport, efficient dissemination, viability for years and the possibility of producing large quantities of infectious material Epidemiological clue - rapid onset of an outbreak of febrile illness in urban setting w/ peak of cases, implicating point-source exposure w/o secondary transmission Pathogenesis ∙Has unique mode of damaging arterial wall ∙Single organism can cause illness ∙Doughnut granuloma consists of fibrinoid ring w/ clear lipid center and surrounded by PMNs and epithelioid cells ∙Coxiella can persist in nature as spore-like structure and can infect people w/o known contact w/ animals ∙Granulomas form as a result of DTH to protect against intracellular organisms Clinical features ∙Acute - usually self-liited, can present as flu-like symptoms, pneumonia, hematuria, or hepatitis ∙Chronic - prolonged fever of unexplained origin, granulomatous hepatitis and atypical pneumonia (productive cough and pleuritic chest pain) • Infective endocarditis is major manifestation of chronic Q fever (accounts for 60-70% of chronic cases), involving aortic valve most commonly • Fatality is 1-2% Dx: ∙Unexplained fevers, negative blood cultures, nml WBC count, unexplained elevated hepatic enzymes, thrombocytopenia, hepatosplenomegaly ∙Dx made by serology ∙PCR is gold standard R = doxycycline (100mgBID for 14 days), FQ is pt develops meningitis ∙Doxy w/ hydroxychloroquine (makes organism more susceptible to doxy by elevated pH in phagolysosome vacuole of monocyte) and rifampin recommended for 18-36 months if pt develops endocarditis ∙Co-trimoxazole recommended for children <8

AIDS Indicator Parasites

Cryptosporidiosis - chronic intestinal (>one month's duration) Isosporiasis - chronic intestinal (> one month's duration) Toxoplasmosis of brain

Diagnosis and treatment of C. perfringens

Culture, isolation, identification by biochemical tests, immunoassays Tissue debridement, *high dose penicillin*, hyperbaric oxygen Ubiquitous so proper wound care and judicious use of prophylactic antibiotics can prevent infection

Clinical classifications of fungi

Cutaneous mycoses ∙Dermatophytes →Molds →*Cause ringworm, also known as tinea* →Infect skin, nails, hair (keratinized cells) ∙Cutaneous/mucocutaneous candidiasis Superficial mycoses ∙Linea versicolor ∙Malassezia furfur - normal skin flora Subcutaneous mycoses ∙Direct inoculation into a puncture wound ∙Sporothrix schenkii →Associated with infection via puncture wound →Dimorphic fungus →Associated with rose bushes & mulch - occupational hazard of landscapers, garden workers →Subcutaneous ulcers that spread along the lymphatics draining the primary lesion Systemic mycoses ∙Involve internal organs ∙Can be rapidly fatal ∙Often caused by opportunistic pathogens ∙Endemic mycoses →Found in specific regions in the world →Not opportunistic, but more likely to disseminate if the host is immunocompromised

Proinflammatory cytokines

Cytokines = IL-1, IL-6, TNF-α

Definitions for cytokines

Cytokines = polypeptides produced in response to microbes or other antigens that mediate and regulate immune and inflammatory rxns Lymphokines = cytokines secreted by lymphocytes Some cytokines are called interleukins b/c many cytokines are made by leukocytes and act on other leukocytes (IL-1 to IL-35+)

Clinical illnesses in beta herpesviruses

Cytomegalovirus Human herpesvirus 6 & 7

Drug interactions w/ azoles

Decreased plasma concentrations of the anti-fungal drug ∙Decreased absorption ∙Increased metabolism Enhance toxicity of co-administered drug ∙Increase the plasma concentration of other drugs by altering hepatic metabolism via the P-450 system

General features of the immune response to microbes

Defense against microbes is mediated by the effector mechanisms of innate and adaptive immunity The immune system responds in distinct and specialized ways to different types of microbes to most effectively combat these agents The survival and pathogenicity of microbes in a host are critically influenced by the ability of the microbes to evade/resist effector mechanisms of immunity In many infections, tissue injury and disease may be caused by the host response to the microbe and its products rather than the microbe itself

Pathologic aspects of wound repair

Deficient scar formation - two complications ∙Wound dehiscence (rupture) ∙Ulceration *Excessive formation of the repair components* ∙Accumulation of excessive collagen (keloid or hypertrophic scar) ∙Excessive granulation tissue (exuberant granulation or proud flesh) ∙Exuberant proliferation of fibroblasts (desmoids or aggressive fibromatoses) - may be hyperplasia or neoplasia Contracture formation ∙An exaggeration of normal contraction of wound - palms, soles, anterior aspect of thorax all prone - often seen after serious burns *NOTE: Chronic inflammatory fibrosis - eg, rheumatoid arthritis, lung fibrosis, hepatic cirrhosis maintain persistent stimulus for fibroplasia - all involve leukocyte-macrophage interaction maintaining damage-repair scenario*

NK cells

Definition: mononuclear lymphocyte that lacks CD3 and expresses CD56 (adhesion molecule) Most are large granular lymphocytes (LGL) ∙Well developed cytosol containing cytotoxic granules 10-15% of PBL No rearrangements of TCR or Ig genes Express IL-Rb and IL-2Rγ ∙Allow responsiveness to IL-2 *Provide innate immunity against intracellular infections, particularly viruses* Migrate from blood to tissue in response to inflammatory cytokines *People who lack NK cells suffer from persistent viral infections* ∙Rare disorder ∙Herpes common

What is delayed type hypersensitivity?

Delayed type hypersensitivity describes a cell mediated immune response in vivo, particularly the activation of local macrophages by antigen-activated CD4+ Th1 effector cells and their cytokine products A DTH rxn (signifying the presence of CD4+ Th1 effector cells) can be demonstrated in vivo

Viral disease

Development of disease depends upon whether or not the pathogen can overwhelm the immune response Symptoms of disease ∙Can be a direct result of virus infecting and killing a cell ∙OR a result of the immune response to the virus-infected cells (immune-mediated disease) Infection can be subclinical or asymptomatic ∙Virus can still be shed and transmitted to a new host Viral factors influencing disease ∙Transmission of virus determines the site of entry →Example: STDs enter via the genitals, respiratory infections enter via the mouth and nose ∙Inoculum size (how much virus you're in contact with) influences the severity of infection ∙Tissue tropism affects the infection ∙Viral virulence factors →Mechanisms to control the host cell protein synthesis →Mechanisms to evade the immune response →Mechanisms to directly damage the cells Host factors influencing disease ∙Immune status of the host →Compromised vs. non-compromised immunity and prior immunity to the agent ∙General health of the patient →Nutrition ∙Age ∙Genetic background

Cell mediated immunity involves both CD4+ and CD8+ T cells

Diagram also shows the various stages of adaptive cell mediated immune response The induction of an immune response, which begins w/ T cell activation, proliferation and differentiation, occurs in secondary lymphoid tissue ∙Antigen is carried from peripheral tissues by dendritic cells Differentiated effector cells enter the circulation and migrate, w/ other immune and inflammatory cells, to site of infection ∙When they encounter their antigens at the site of the infection, they exert their effector function ∙For CD8+ T cells, this means that the cells exert their cytotoxic function ∙For CD4+ T cells, this means that they secrete cytokines, which influence the activity of other immune and inflammatory cells

Type II and Type III hypersensitivity rxns: Pathophysiology

Difference is whether or not antigen in free or bound to cell Hypersensitivity = immune response WITH TISSUE DAMAGE

Diagnosis of Non-Spore Forming Gram (-) Bacteria

Difficult to isolate so usually made on clinical setting Microscopy ∙Finding pleomorphic, gram (-) rods can be important preliminary information Culture ∙Use oxygen free system from transport ∙Longer incubation periods may be needed for growth of some anaerobes ∙Use of differential and selective media useful

Diflunisal (DOLOBID)

Difluorophenyl derivative of salicylic acid Actions: anti-inflammatory (more potent than aspirin), analgesic ∙*No antipyretic effects - poor CNS penetration ∙Insignificant prolongation of bleeding time - less antiplatelet activity ∙Less occult blood loss than aspirin (loss via stool)*

Endemic mycoses

Dimorphic fungi ∙Inhale mold form (infectious form) ∙Yeast form replicates in tissue Many cases are mild (flu-like) or asymptomatic Most people in endemic area are skin test positive Immunocompromised patients are prone to disseminated disease, or maybe elderly pts

Types of fungi causing systemic infections

Dimorphic fungi tends to be the infectious form that is in the environment C. albicans grows as a yeast as part of normal flora; however, it is dimorphic and can form hyphae and pseudohyphae when it causes invasive disease

Side Effects of Diflunisal

Dizziness Nephritis Gastric ulceration NO TINNITUS

C. perfringens analysis

Don't usually see spores in tissue or when cultured ∙Characteristic box car shape Double zone of hemolysis when cultured Some organisms may become decolorized ∙No inflammatory cells (lysed by alpha-toxin)

Herpesvirus family

Double stranded DNA virus (so has the potential for latency and reactivation) Is enveloped with an icosahedral capsid and tegument ∙Tegument is the space between the envelop and capsid Immortalization (EBV) and transformation Oncogenesis (with Epstein Barr Virus and in Kaposi's Sarcoma Herpesvirus (KSHV)) ∙Herpes virus sequences were recently found in KSHV Frequently reactivated in compromised hosts because of lowered immune response

Activity of antifungals for Candida spp.

Drug Abbreviations ∙AMB, amphotericin B ∙FC, flucytosine ∙KTZ, ketoconazole ∙ITZ, itraconazole ∙FCZ, fluconazole ∙VCZ, voriconazole ∙ECH, echinocandins Symbols ∙0, inactive or not recommended ∙+, occasional activity ∙++, moderate activity with resistance noted ∙+++ reliable activity with occasional resistance ∙++++ very active, resistance rare or not described

Strong immune responses require some degree of inflammation

During infection-initiated by microbial products ∙Activate macrophages →Increase expression of co-stimulators (if the adjuvant is microbial) ∙Recruit inflammatory cells

Diagnosis of Toxoplasmosis

Dx: ELISA, dye test, CT, IFA, histology ∙Maternal infection (based on US and serology) must be confirmed by prenatal diagnosis by PCR of amniotic fluid ∙Presence of hydrocephalus has been used as an indication for termination of pregnancy DDX: CNSD lymphoma, progressive multifocal leukoencephalopathy, CMV ventriculitis and encephalitis, cryptococcoma, tuberculoma, aspergilloma, nocardiosis and brain abscess In MA, VT, and NH, all newborns are tested for toxoplasmosis and treated for 1 yr if identified ∙Incidence in live births in USA is 1-5/10,000

Viral transcription: General properties

Early transcripts (take over the cell) ∙Encode regulatory enzymes and proteins →Control transcription of viral mRNAs →Initiate replication of the viral genome →Shut down host's protein synthesis Late transcripts (prepare for replication and exit of viruses) ∙Encode viral structural proteins

Fungal inhibitors of cell wall synthesis

Echinocandins - caspofungin, micafungin, anidulafungin ∙Inhibits β-glucan synthase; cell wall β-(1,3)-glucans are not made ∙Disrupts the osmotic environment of the cell, as well as cell division & growth ∙Active against fungi where β-(1,3)-glucans are a dominant component of the cell wall →Candida →Aspergillus →These cause invasive candidiasis & invasive aspergillosis (respectively) when amphotericin B is not effective

Lactobacillus

Either facultative or obligate anaerobes Normal flora of mouth, stomach, intestine, and GI tract Used as probiotics *Endocarditis and septicemia in compromised patients* *Resistant to vancomycin* ∙Combination antibiotic therapy indicated

Flucytosine

Enters the cells via cytosine permease Deaminated & phosphorylated to form 5-FUMP → 5-FUDP → 5-FUTP Competes with uracil for RNA synthesis Inhibits both RNA & DNA synthesis Used for cryptococcal meningitis, some Candida spp. (especially endocarditis & meningitis) ∙Good penetration into the CNS *Not used as monotherapy because of the possibility of developing resistant organisms* ∙Usually used with amphotericin B or azoles Adverse effects: ∙Myelosuppression (especially neutropenia) ∙Other possible effects - renal insufficiency; diarrhea, vomiting, nausea & liver enzyme abnormalities

Stem cell role in epithelialization

Epithelial Stem Cells found in 3 skin niches ∙Hair follicle bulge (HF) ∙Sebaceous gland base ∙Interfollicular epidermis (IFE) Which delivers cells to wound? ∙In homeostasis: Each proliferates within its own niche ∙In wound healing: Both HF and IFE are involved ∙HF first to migrate to wound

Acute GVH

Epithelial cell necrosis in liver, skin, GI Skin rash, diarrhea and jaundice Can be fatal

Babesiosis

Etiology - Babesia microti and WAI piroplasm ∙Natural host = white-footed mouse for nymphs, and white-tailed eer for adult ticks ∙May coexist w/ Lyme Borreliosis ∙Geographic distribution = northeastern costal areas ∙Peak incidence in July Risk factors - advanced age, asplenic state, immune-suppression Clinical features - fever, shaking chills, sweats, arthralgia, nausea, fatigue and myalgia ∙hemolytic anemia, jaundice in asplenic cases ∙emotional lability or depression has also been described ∙renal failures, DIC and ARDS may be seen in severe cases ∙Relative bradycardia seen in babesiosis, malaria, yellow fever, dengue fever, Ebola, typhoid, RMSF, etc. Complications - ARDS, DIC, CCF, coma, liver and kidney failure, splenic rupture Dx: ∙Peripheral blood smears for intra-erythrocytic tetrads or Maltese cross or dumb-bell shaped piroplasms (ring forms) will line up in a distinctive X-shaped pattern ∙Serology is best performed by immunofluorescent antibody ∙May be moderate hepatosplenomegaly or possibly jaundice and dark urine ∙Thrombocytopenia, elevated hepatic transaminases, bilirubin and LDH, reticulocytosis, lymphopenia and hemoglobinuria may be observed ∙PCR RX: clindamycin, quinine sulfate, azithromycin, atovaquone (7-10days) ∙Exchange blood transfusion and renal dialysis in severe cases ∙Pts w/ LD who experience a prolonged flu-like illness that does not improve w/ anti-borrelial therapy should be tested for babesiosis Prevention: tick repellants, avoidance of outdoor activities, thorough examination for ticks

General characteristics of fungi

Eukaryotic ∙Nucleus w/ nuclear membrane ∙Subcellular organelles: mitochondria, ribosomes, ER, golgi, microtubules Plasmalemma (plasma membrane) composed of glycoproteins, lipids & *ergosterol* ∙Ergosterol is unique to fungal cells, so target for therapy Cell wall contains chitin (polymer of N-acetyl glucosamine), mannans, glucans and other complex carbohydrates ∙Has cell wall unlike mammalian cells

LD Risk Factors

Exposure to wooded or grassy areas Recreational activity - hiking, camping, fishing, hunting Occupational - telephone workers, landscape, forestry, park management, veterinarians, wilderness construction crews, ranchers, field workers, anthropologists and mine workers Ticks favor a moist, shaded environment provided by leaf litter and low lying vegetations

Ixodids

Feed for relatively long periods and remain firmly attacked to the host The tick bite/attachment is painless and the tick spends 90% of their life unattached from the host Exophilic - live in open environment, meadows or forests Attracted by feet hitting the group or CO2 emitted by car stopped in bush

Fibrosis

Fibroblast proliferation ∙Provisional stroma for fibroblast in-growth ∙Growth factors promote migration and proliferation to site of injury ∙TGFβ most important →Expressed in chronic fibrotic diseases ECM deposition ∙w/ ongoing repair, numbers of fibroblasts and endothelial cells decrease ∙More fibrillar collagen (Types I, II, III) made at this time - important for wound strength ∙Growth factors important here ∙NOTE: net collagen accumulation - a function of collagen synthesis + collagen degradation Tissue remodeling ∙Replacing granulation tissue w/ a scar ∙Net result of ECM synthesis vs. degradation →Important in both chronic inflammation and wound repair ∙Degradation of collagen and other ECM proteins - matrix metalloproteinases (Zn2+ dependent) →i.e. interstitial collagenases, gelatinases, stromelysins ∙MMPs are rapidly inhibited by tissue inhibitors of metalloproteinase (TIMPS)

Temporary ECM: Granulation Tissue

Fibroblasts produce ECM proteins Assembled into temporary matrix for cell migration and adhesion ECM Molecules: ∙Fibronectin ∙Thrombospondin ∙Laminin ∙Vitronectin ∙Collagen - Collagen III>Collagen I (opposite to normal ECM) ∙Proteoglycans ∙Elastin - Not present in granulation tissue

Chronic GVH

Fibrosis and atrophy of skin Chronic liver disease: cholestatic jaundice GI: esophageal strictures Get life threatening infections, b/c immune system devastated May be fatal

Repair

Fibrous scar produced from granulation tissue replaces lost tissue The repair cascade is a continuous process that can be divided into discrete sets of overlapping cellular and biochemical events ∙Note: different tissues have their own characteristic patterns

Hemostasis

First phase of wound repair Platelets ∙Activation by bumping against wounded surfaces →Causes change in shape, surface structure and secretions ∙Aggregation →Response to activation →Form platelet plug that stops bleeding →Serve as a surface for thrombin formation ∙Secretions activate next phase of wound repair →Recruit inflammatory cells →Blood clot formation Platelet secretions & clot → cell recruitment ∙Neutrophils recruited w/in minutes →Neutrophils are also activated by wounds they bump into in the walls →Neutrophil secretions form a chemical gradient to attract more neutrophils there ∙Monocytes → macrophage (2-3 days)

Toxicities of IFNs

Flu-like symptoms ∙Fever ∙Chills ∙Malaise ∙Myalgias ∙Myelosuppression ∙Headache ∙Depression

Specific uses of various azoles

Fluconazole - cryptococcal meningitis ∙Good CNS penetration ∙Also mucocutaneous candidiasis; coccidioidal meningitis ∙Used as prophylaxis in bone marrow transplants Itraconazole ∙Prophylaxis in neutropenic patients ∙Dermatophyte infections; onychomycosis Voriconazole - invasive aspergillosis ∙Also Candida & dimorphic fungi Posaconazole - mucormycosis ∙Also Candida & Aspergillus

Inhibition of intracellular processes

Flucytosine (5-fluorocytosine)→ Fluorinated pyrimidine

TORCH Screen

For congenital malformations T - toxoplasma O - other R - rubella C - CMV H - herpes, hepatitis, HIV S - syphilis

Granulomatous hypersensitivity and inflammation

Form of type 4 hypersensitivity Occurs when antigen is not cleared Persistent T cell activation and release of cytokines promotes differentiation of macrophages into epithelioid cells, which secrete TNFa ∙epithelioid = large macrophages looks like epithelial cell w/ small nucleus and amount of cytoplasm, pro-inflammatory some fuse to form multinucleate giant cells

Systemic immune complex disease is divided into 3 stages

Formation of immune complexes ∙Initiated by introduction of antigen (usually a protein) ∙Interaction w/ immunocompetent cells ∙Formation of antibody →Secreted into blood where they interact w/ antigen →Form immune complexes Deposition of immune complexes ∙Factors that favor deposition not fully understood →Size of complexes →→→Large complexes formed when there is an excess of antibody are rapidly removed by phagocytosis →→→Immune complex deposition is favored when complexes are smaller (when antigen is in excess) →If mononuclear phagocytes are overloaded or defective, there is an increased likelihood of deposition ∙Favored sites for immune complex deposition →Kidney (glomerulonephritis) →Joints (arthritis) →Skin →Heart →Serosal surfaces →Small vessels (Vasculitis) ∙For immune complexes to leave the circulation, there must be a change in vascular permeability →Immune complexes bind to inflammatory cells through FcR or C3bR →Trigger release of vasoactive amines and cytokines →Mast cells also involved Tissue injury caused by immune complexes ∙Clinical signs associated w/ deposition of immune complexes in the tissue and induction of an inflammatory rxn →Fever →Urticaria →Arthralgias →Lymphadenopathy →Proteinuria ∙Mechanisms for tissue damage are similar to that for type II hypersensitivity disorders ∙In general, damage proceeds via 2 mechanisms →Activation of complement cascade →→→Promotes inflammation via production of chemotactic factors, which direct migration of PMNs and monocytes (C5a) →→→And release of anaphylatoxins (C3a and C5a) →Activation of neutrophils and macrophages via FcR →→→Release of proinflammatory substances →Prostaglandins →Vasodilators →Chemotactic factors →Lysosomal enzymes →→→Reactive oxygen species ∙Other effects of immune complexes →Platelet aggregation →Both result in formation of microthrombi

Tenesmus

Frequent urge to defecate w/ just the passage of blood and mucous

Importance of fungal pathogens

Fungi as opportunistic & nosocomial pathogens ∙4th or 5th leading cause of nosocomial infection ∙Important b/c population of susceptible hosts is increasing ∙Antibiotics limit bacteria infections but favor fungal infections →May eliminate pathogens but also normal flora, opening niche for fungal pathogens to colonize Why fungal infections are life threatening or fatal ∙Host is compromised to begin with ∙Often misdiagnosed →If treated as bacterial infection, may actually HELP fungal infection take off ∙Illness progresses rapidly ∙Lack of safe & effective antifungals

Side effects of ibuprofen

GI Epigastric pain, nausea, heartburn, sensation of "fullness" Gastric, duodenal, intestinal erosions (but less than aspirin) Occult blood loss uncommon Ocular disturbances, skin rashes, headache

Galectins of known function

Gal 3 ∙Present in Inflammatory cells, epithelia, fibroblasts, extra- and intra-cellularly ∙Active in corneal, GI, skin, wound healing ∙Active in migration, not proliferation Gal 7 ∙Forms homodimers (not multivalent) ∙Marker for stratified epithelia ∙Active in corneal, skin, kidney and uterine healing Gal 2 and 4 ∙Expressed in GI ∙Enhances epithelial migration and proliferation

Clostridial myonecrosis

Gas gangrene Intense pain 1 week after infection Toxins damage/kill cells Enzymes (collagenase, hyaluronidase) facilitate spread Metabolic activity of the organism leads to gas formation (crepitation) Extensive necrosis, copious & foul smelling exudates Dissemination of the toxins can lead to shock, renal failure & death (within 2 days of onset!)

Transcription of double-stranded RNA viruses

Genome is segmented ∙Each segment encodes a protein Virus encodes an RNA-dependent RNA polymerase ∙Core protein

Bacteroides

Gram (-) but LPS has minimal endotoxic activity *Most common cause of serious anaerobic infections* ∙Sepsis ∙Peritonitis ∙Abscesses *B. fragilis most frequent pathogenic species* (but minor in # in GI tract) Look like a mixed population of bacteria in gram stain preparations Virulence factors ∙Polysaccharide capsule is antiphagocytic ∙Anaerobic metabolism products inhibit phagocytosis and intracellular killing ∙Fimbriae ∙*B-lactamase* ∙Enterotoxigenic strains of B. fragilis cause diarrhea

Tissue Remodeling Phase

Granulation tissue from proliferative phase can become large scar if remodeling does not proceed well Phases ∙Contraction →Fibroblasts → myofibroblasts containing actin that contract wound ∙Endothelial capillaries that fed granulation tissue →Some apoptose →Others join and connect in normal pattern to vasculature ∙ECM changes →Granulation tissue is remodeled (>collagen type III →>collagen type I) →Elastin is produced (missing in granulation tissue) →Collagen & other proteins reorganize to support normal epidermal and dermal tissue →Scar tissue gradually is replaced (1 yr) Matric metalloproteinases (MMPs) ∙Digestive enzymes released from cells ∙Zn²⁺-dependent, Ca²⁺-activated ∙Digest ECM for remodeling

Listeria monocytogenes

Green = actin tail Red = organism This is how organism is moved through cell once it has invaded, allowing it to escape and infect other parts of body

HSV-1

HSV-1 Infections: ∙*Leading cause of sporadic viral encephalitis* ∙Most of herpes simplex 1 (HSV-1) caused by Type 1 ∙Oral: Gingivostomatitis, Tonsillitis, Labialis ∙Whitlow: occurs on fingers - Used to occur in the past if a dentist was not wearing gloves and patient was shedding herpes virus, also occurs with children that suck their thumbs ∙Genital ∙Gladiatorum: problem with wrestlers because of skin-to-skin contact, can lead to lesions on the body ∙Pharyngitis ∙Esophagitis ∙Keratoconjuctivitis HSV-1 Oral Herpes ∙Transmission via contact with contaminated saliva ∙Remains localized at oral mucosa and is associated with lesions in and around the mouth ∙Enters neurons at site of infection and travels via retrograde transport to the trigeminal ganglion (establishes latent infection) ∙Cold sore represents reactivation of infection, but reactivation tends to be shorter than the primary infection because body already has antibodies

HSV-2 infections: associated with general lesions over body

HSV-2 Infections: ∙Meningitis associated with genital herpes ∙Oral ∙Pharyngitis ∙Whitlow ∙Perianal ∙Neonatal Herpes: the mother has a primary infection and the baby will get neonatal herpes, encephalitis is associated HSV-2 Genital Herpes ∙Sexually transmitted ∙Remains localized at genital mucosa ∙Enters neurons at site of infection ∙Travels via retrograde transport to the sacral ganglion (establishes latent infection)

Pediculosis Human Capitis

Head louse Head-lice infestation - lice are blood sucking obligate ectoparasites and are transmitted by contact b/w heads and comb/towel sharing ∙Also transmitted by lying on a bed, pillow, couch, carpet or stuffed animal that has recently been in contact w/ an infested person ∙Also by wearing infesting clothing, hats, scarves, etc. Lice infestations are highly contagious, intensely pruritic and often misdiagnosed Infested people are the reservoir Diet is 100% liquid Most parasitic of all insects There is no free-living stage in life cycle ∙They are born, live and die on host Produces dry, solid, black, gritty feces (on pillows) Last thing a louse needs is for the host to clean and groom itself Has the ability to assume an apparent moribund state, before later resurrecting from seeming death Three forms: nit, nymph (baby louse), and adult ∙Size of adult louse is of a match head or sesame seed ∙Size of nit is pinhead Head louse lifespan is 30 days ∙Lays 10 eggs/day ∙Can move 23cm (9") in a minute Common sites: on scalp behind ears and near neckline Symptoms ∙Pruritus of scalp is cardinal symptom, due to sensitization of louse saliva and antigens ∙Children are distracted, restless and inattentive at school ∙Tickling feeling of something moving in hair ∙Irritability ∙Soreness on head ∙Post-cervical lymphadenopathy Lice are firmly cemented to hair by pincer-like claws Nits are tulip-shaped eggs ∙Grayish-white or creamy yellow ∙Have pearly fluorescence under UV light ∙Lice infestation may look like artifacts such as dandruff, hairspray droplets, scabs, dirt, knotted hair and insects blown in by the wind and caught in the hair Phx: regular grooming Rx: bug buster kit, pyrethroids and pyrethrins (natural extracts from chrysanthemum flower) and Permethrins such as Rid or Nix are safe, photostable, easy to use and available OTC ∙Lindane shampoo (kwell) has the problem of causing neurotoxicity (seizure) and should not be used immediately after shower ∙Insecticide should be put on dry hair or can be left on overnight under a shower cap ∙Ivermectin (stromectol) either stopical or oral has been used successfully for resistant lice infestations ∙White vinegar applied to hair loosens nits ∙Shaving scalp is highly successful Asymptomatic carriage in siblings and parents

Capsids

Helical (no human pathogens that are naked and helical) Icosadehron Icosadeltahedron

Helminthes

Helminthes are multicellular organisms ∙Helminthiasis is the most common group of diseases in the world *Unremittingly corrosive* Examples ∙Nematodes - round worms ∙Platyhelminths - flat worms ∙Cestodes - tape worms ∙Trematodes - flukes *Helminths cause chronic infections:* ∙Complexity of genome ∙Multiple developmental stages ∙Antigen variation ∙Conservation of sequences ∙Use of host derived cells for sequestration ∙Antigen masking Pathogenicity ∙Mechanical ∙Invasion and destruction of host cells ∙Inflammation ∙Competition for host nutrients ∙Worm burden

Angiogenesis from endothelial precursor cells

Hemangioblast ∙Link hematopoietic and vascular systems during embryonic development producing hematopoietic stem cells and angioblasts Angioblasts ∙Proliferate and migrate to peripheral sites and differentiate into endothelial cells that form arteries, veins and lymphatics, pericytes and smooth muscle cells

Hemolytic disease of the newborn

Hemolytic disease of newborn occurs principally in the Rh+ offspring of mothers who are Rh- and have igG antibodies to very immunogenic RhD antigen The Rh- mother is usually sensitized to the RhD antigen while carrying her first Rh+ fetus ∙While the fetal RBC (bearing RhD antigen) are normally separated from the maternal circulation by the placenta, fetal RBC may escape into maternal circulation either late in pregnancy or during childbirth ∙These Rh+ RBC sensitize the maternal immune system and generates high titer IgG specific for the RhD antigen ∙Upon subsequent pregnancy, these IgG antibodies can cross the placenta, enter the fetal bloodstream and destroy fetal RBC, resulting in anemia

Overlapping stages of wound healing

Hemostasis ∙Platelets ∙Coagulation proteins ∙Clot scaffold Inflammation ∙PMNs, mono/macrophages, fibroblasts ∙Primary scaffold granulation tissue) Proliferation ∙Epithelialization - any kind of epithelial tissue that need repair ∙Angiogenesis Tissue remodeling ∙Apoptosis, differentiation ∙Protein synthesis ∙Scaffolding reorganization ∙Scar removal

Side effects of acetaminophen

Hepatotoxicity (seems to be related to p450 system) ∙Children must more likely to be affected (can cause death) NO GI effects, NO prolongation of bleeding time, NO effects of renal function or acid-base equilibrium

First wave of mediators (pre-formed)

Histamine (vasoactive amine) ∙Acts on receptors (H1, H2, H3) →H1 probably most important in allergic responses →H2 can be seen in individuals who have had allergies for long periods of time ∙Acts on: →Smooth muscle: contraction →Blood vessel endothelium: causing increased vascular permeability and inflammation →Epithelium of mucosa: mucus production Heparin: anti-coagulant Chondroitin sulfate Enzymes ∙Neutral proteases and acid hydrolases ∙Cause tissue damage; lead to the production of kinins and activated complement components (such as C3a) TNF-α ∙Mast cells are only cells that can store TNF-α ∙Acts in concert with histamine →Activates endothelial cells →Increases expression of adhesion molecules

Viral envelope

Host-derived lipid membrane (can be from any membrane like the golgi, ER, etc) Viral encoded proteins ∙Matrix proteins →Involved in assembly, makes sure when virus is assembled, the capsid is in contact with a membrane and isn't empty ∙Surface (envelope) glycoproteins →Involved in viral attachment →Virus-cell fusion allowing it to enter the cell →Induce neutralizing (protective) antibody →→→Response raised against surface glycoproteins →→→Neutralizing antibodies prevent infection

Cell recruitment, migration, reattachment

How do stationary (fixed) cells respond to chemical recruitment? ∙Attachment sites need to be broken ∙To move, lamelipodia form and reform through intracellular rearrangements of actin ∙Upon arrival, attachment sites reform

Ehrlichiosis/Anaplasmosis

Human erlichioses represent one of the best examples of newly emergent infections in which the classic triad of host, infectious agent and environment are intertwined closely Erlichiosis is an emerging zoonotic infection caused by obligate gram (-) intracellular bacteria ∙Peak season is late spring through midsummer Epidemiology - ticks are vectors and white-tailed deer is reservoir ∙Disease cycle components - pathogen, animal reservoir, vector and human host HGE (Human Anaplasmosis) found in upper Midwest and eastern US ∙Causative agent is E. phagocytophila (now known as Anaplasma phagocytophilm) →E. ewingii is a variant of HE in Missouri, Oklahoma, Tennessee ∙Ticks are Ixodes scapularis and Dermacentor variabilis HME (Human Monocytic Erlichiosis) ∙Causative agent E. chaffeensis ∙Vector is lone star tick (amblyomma americanum), ranging from eastern Texas to Atlantic ocean Pathogenesis ∙Incubation period = 7-10 days ∙Organism is obligate intracellular gram (-), pleomorphic, coccoid bacterium ∙Organisms are phagocytosed by circulating leukocytes ∙They form vacuole-bound microcolonies of cytoplasmic inclusion bodies called morulae that rupture in the blood stream and infect other leukocytes ∙Morulae appear like mulberries on Wright-stained peripheral blood smears as stippled blue inclusions Clinical features = fever, shaking chills, malaise, headache, myalgia, stupor, hallucinations, seizure, coma, ARDS, DIC, renal and respiratory failure ∙1/3 pts develop rash, which is erythematous and confluent, but sparing palms and soles ∙any pt evaluated for fever, thrombocytopenia and leukopenia should be considered for diagnosis of ehrlichiosis regardless of history of tick attachment ∙Lab values show leukopenia w/ absolute lymphopenia, thrombocytopenia, anemia, pulmonary infiltrates, elevated ESR and CRP and raised aminotransferase levels ∙Can easily be misdiagnosed as the summer flu b/c of its elusive clinical presentation Co-infection w/ LD should be considered in pts presenting w/ high grade fever despite receiving appropriate antibiotics, or unresolved/worsening viral infection-like syndrome after resolution of EM Dx: ∙Serology is the gold standard (seroconversion during convalescence marked by a 4x change in antibody titer) ∙PCR ∙Peripheral blood smear for intraleukocytic morulae ∙Leukopenia, thrombocytopenia, and elevated hepatic transaminases Complications include meningoencephalitis, ARDS, sepsis, renal failure, coagulopathy and multiorgan failure Rx: doxycycline or tetracycline as 100mg BID for 14 days

Abthrax (Raxibacumab)

Human monoclonal Ab that is approved for inhalational anthrax Targets protective antigen and prevents F and EF from entering cells Administered single dose IV

Conseqeunces of PLC Activation

Hydrolysis of PIP2 ∙Formation of DAG ∙Activation of PKC-q (a "novel" PKC isoform found only in T cells and muscle) ∙Activation of ras Formation of IP3 ∙Opening of Ca channels in the ER ∙Then, opening of Ca channels in the plasma membrane Consequences of increased [Ca] ∙Calcium binds to and activates calmodulin ∙Calmodulin activates calcineurin ∙Calcineurin is a serine/threonine phosphatase ∙Calcineurin dephosphorylates cytoplasmic NFAT

Hyphae

Hyphae = filaments or tubular structures of molds ∙Two different types: septated and aseptated ∙Helps determine difference b/w pathogens →Can cause similar type of clinical disease Hyphae with cross walls (septa) are septated ∙Aspergillus Hyphae without septa are nonseptated (aseptate) ∙BOTH OF THESE ARE MOLDS ∙Mucormycetes (formerly called Zygomycetes) ∙Genera include: Mucor, Rhizopus & Lichtheimia (formerly called Absidia)

Pseudohyphae

Hyphae-like structure formed by incomplete budding of yeast cells Constricted at their point of attachment ∙So where it is budding off of mother cell, it is more narrow ∙True hyphae have the same diameter Candida albicans

Clonal expansion of activation T cells

IL-2 ∙From CD4+ T cells or CD8+ T cells themselves ∙May be promoted by pro-inflammatory cytokines (TNF-α, IL-1, IL-12) Others ∙IL-12 (may also be involved in differentiation) ∙IL-15 →Structurally similar to IL-2 →Rα chain similar to IL-2Rα, same Rβ and Rγ chains ∙IL-7

Growth factor cytokines

IL-2, IL-4, IL-7, IL-15

Hypersensitivity rxns occur in two phases

Image is looking at ability to move air through airway The major drop in the immediate time frame is in response to major release of histamine, and contraction of airway ∙Can happen as quickly as 2 minutes for those w/ severe allergy Will get return to normal after about 1-2 hrs, b/c the mediators are used up We are calling in additional leukocytes, however, so after about 6-8 hours we get a second wave ∙Much larger edema taking place ∙Late-phase mediators responsible for this ∙Late phase can take place sometimes as late as 16-18 hours after antigen challenge

Azoles

Imidazoles & triazoles ∙Differ by # of "N" in the azole ring Inhibit lanosterol 14-α-demethylase ∙Cytochrome P-450-dependent enzyme, which converts lanosterol to ergosterol →b/c of this, there will be some drug-drug interactions ∙Binds to the heme moiety of cytochrome P-450

Role of B cells in the immune response: Production of antibodies

Important for clearance of organisms present in the extracellular space ∙Free virus →Replicate inside cells →Get from one cell to another via extracellular space ∙Bacteria Not toxic by themselves ∙Neutralization ∙Opsonization (promotes phagocytosis) →Promoted by complement ∙Targets for complement-mediated destruction

IL-12

Important mediator of early innate immune response to intracellular microbes Cellular sources: ∙Mononuclear phagocytes ∙Dendritic cells Biologic effects: *Key inducer/regulator of cell-mediated immunity* ∙Activator of NK cells ∙Stimulates IFN- γ production (which also activates NK cells) ∙Stimulates differentiation of Th0 cells to Th1 ∙Enhances cytolytic function of NK cells and CD8+

Bone Marrow & Chronic Inflammation

In bone marrow, you can have differentiation of many different cell lineages Histiocytes = tissue macrophages

Antibody mediated cellular dysfunction

In some cases, antibodies directed against cell surface molecules, such as receptors, impair or otherwise alter the function of that protein w/o causing cell injury or inducing inflammation Three examples: ∙Myasthenia gravis →Antibody against ACh receptor →Blocks ACh binding at the motor end plates of skeletal muscle →Progressive muscle weakness →Autoimmune disorder ∙Pemphigus vulgaris →Antibody against proteins associated w/ intracellular junctions associated w/ epidermal cells →Disrupt intracellular junctions in epidermis →Skin vesicles ∙Graves disease →Antibodies against the thyroid stimulating hormone receptor on thyroid epithelial cells stimulate the cell →Hyperthyroidism

Intermediate host

In which the asexual stage of parasite's life cycle takes place

Definitive host

In which the sexual stage of parasite's life cycle is completed

Healing by first intention (wounds w/ opposed edges)

Incision ∙Death of epithelial and connective tissue cells - basement membrane disruption - blood clot filled with fibrin & blood cells - scab upon dehydration 24hrs ∙PMNs at margins - migrate to clot - epidermis thickens at cut edge - mitotic activity of basal cells increased 24-48hrs ∙Epithelial spurs migrate & grow along cut margins of dermis - basement membrane laid down - epithelial cells fuse at midline Day 3 ∙PMNs replaced by macs - granulation tissue invades incision space - vertically oriented collagen fibers appear at margins - epithelial cell layer thickens Day 5 ∙Space filled with granulation tissue - max. neovascularization - more abundant collagen fibrils begin to bridge incision - epidermis obtains normal thickness - surface differentiates (normal architecture & keratinization) Second week ∙Collagen continues to accumulate - fibroblast also continue to proliferate - leukocyte infiltrate, edema, increased vessels have disappeared - blanching begins End of first month ∙Scar makes up cellular connective tissue - no inflammatory cells - wound covered by intact epidermis - dermal appendages in incision line permanently lost - tensile strength increases *NOTE* maximal strength may take months to achieve

Factors that cause fever

Increased synthesis of PGE in hypothalamus is associated w/ fever

Clinical features of LD

Incubation period = 7-10 days after tick bite Early localized LD is disease w/in 8 weeks of tick bite ∙Erythema migrans (EM) is the hallmark of early-localized LD →Begins as erythematous macule or papule at site of tick bite and becomes circulator, expanding concentrically over several days →Rash is warm, flat, non-tender and expands gradually →EM is not painful and non-pruritic →Can sometimes have an appearance similar to large and inflamed spider bite →*Classic EM has a bright-red outer border w/ partial central clearing* →caused by inflammaed at the site of B. burgdorferi inoculation, followed by radial extension as the spirochete spreads through the dermis ∙Systemic symptoms include fever, arthralgia, myalgia, malaise, fatigue and lymphadenopathy Early disseminated LD is characterized by multiple EM lesions, 3-5 weeks after tick bite Late persistent LD is greater than 8 weeks after tick bite ∙Features include oligoarticular arthritis (migratory/episodic), encephalopathy w/ memory deficit, irritability and somnolence, and neuropathy w/ distal paresthesia and radiculoneuritis Untreated LD may result in the following: ∙Neurologic (15%) - aseptic lymphocytic meningitis, cranial nerve VII palsy, HA, fatigue, vertigo, confusion, impaired cognition/sleep/hearing/memory and vision may be observed →Neuroborreliosis has been at the center of a perfect medical-sociologic storm ∙Cardiac (5%) - AV conduction block, BBB →Symptoms are palpitations, syncope, dizziness, dyspnea and chest pain ∙Musculoskeletal - includes (60%) migratory polyarthritis, monoarticular (knee) w/ painful, swollen and stiff joint ∙Neuropsychiatric- manifestation of LD in school-age children are often misdiagnosed as learning, behavioral, or attention-deficit disorders

Clinical features of RMSF

Incubation period is 2-14 days after tick bite Rash is petechial, blanching starting on ankles and wrists and then appearing on palms and soles ∙Rash difficult to appreciate in dark-skin patients ∙10% of pts do not develop rash (Rocky Mountain Spotless Fever) ∙In severe cases, the rash may become hemorrhagic, resulting in skin necrosis and gangrene of digits, may be sloughing of skin (digits and genitalia) resembling purpura fulminans Other symptoms include fever, headache, chills, myalgias and abdominal pain ∙May be altered mental status Involvement of scrotum or vulva is a diagnostic clue Periorbital edema and edema of dorsum of hands/feet is a key diagnostic finding (18-20%) Triad- fever, HA and rash w/ a H/O tick exposure Complications/Sequelae: encephalitis, pulmonary edema, cardiac arrhythmia, coagulopathy, GI bleeding, skin necrosis and hemolysis Cause of death: myocarditis

Cyclosporine

Indications: ∙Prevention of graft rejection ∙Treatment of graft vs. host disease after allogeneic bone marrow transplants ∙Certain autoimmune disorders ∙Dermatologic disorders Sometimes used with corticosteroids Mechanism of action: Blocks signaling for IL-2 transcription ∙Binds to cyclophilin ∙Cyclosporine/cyclophilin complex binds calcineurin and blocks calcineurin activation ∙Downstream activation of NFAT blocked as a consequence ∙IL-2 gene transcription blocked ∙Other transcription affected: IFN-γ, IL-3 Numerous toxicities: ∙*Nephrotoxicity* →Makes this drug a double-edged sword →Used for kidney transplants often but causes nephrotoxicity all by itself ∙Hypertension ∙Hyperglycemia ∙Liver disfunction ∙Hirsutism ∙Cholelithiasis (children) ∙Lymphomas and other cancers →Any time immune system dysregulated, it is always associated w/ increased incidence of particular malignancies of immune system

Dx of RMSF

Indirect immunofluorescence or immunoperoxidase staining of skin biopsies Serology - (IFA) BSL-3 facility Lab - thrombocytopenia, hyponatremia, raised LDH

Indole and Indene Acetic Acids

Indomethacin (Indocin) ∙Limited to 8-10 day therapy b/c of severity of side effects ∙Sulindac (Clinoril) is very similar Actions: analgesic, anti-inflammatory, anti-pyretic, MOST POTENT INACTIVATOR OF PLATELETS ∙SIGNIFICANT OCCULT BLOOD LOSS Uses ∙Rheumatoid arthritis, ankylosing spondylitis, acute gout ∙Neonates - close patent ductus arteriosus Mechanism of action ∙Potent inhibitor of COX ∙Inhibits mobility of PMN leukocytes Metabolism ∙Absorbed following oral administration (available for i.v. injection) ∙90% plasma protein bound (and also extensively bound to tissues) Side effects ∙35-50% experience, 20% discontinue ∙Abdominal pain, nausea, anorexia ∙Gastric ulceration ∙Significant occult blood loss ∙CNS effects: severe frontal headache, vertigo, mental clouding, depression, psychosis ∙Skin rashes, allergic reactions, nephritis, aplastic anemia, thrombocytopenia Contraindications ∙Concurrent administration w/ warfarin b/c of increased risk of GI bleeding Drug Interactions ∙Diuretics ∙Antihypertensives of thiazide diuretic class (B-blocker and ACE inhibitors)

Treatment of aspirin toxicity

Induce emesis Gastric lavage Activated charcoal Hydrate Correct acid-base balance

The IL-2R

Induced upon activation of naïve and effector T cells Consists of 2 chains ∙High affinity alpha chain Expressed constitutively in T regs Signaling from receptor utilizes a Jak/STAT pathway

Oocyst

Infectious form containing sporozoites

Histologic features of chronic inflammation

Infiltration of mononuclear cells → monocytes ∙Macrophages, lymphocytes, plasma cells, mast cells, and, at times, eosinophils Tissue destruction → hallmark of chronic inflammation Attempts at healing ∙Connective tissue replacement, angiogenesis, fibrosis (fibroblasts make collagen in an attempt to fix injury, can easily become excessive)

Chronic inflammation

Inflammation of prolonged duration ∙Active inflammation → tissue destruction → attempts at repair proceed simultaneously Note: may follow acute inflammation ∙Often begins insidiously as low-grade, smoldering, asymptomatic response w/in 48 hours after acute inflammation, monocytes predominate in areas of chronic inflammation monocyte migration similar to that of PMNs monocyte transforms in tissues to macrophage ∙macrophage = central player in chronic inflammation →b/c it produces a large variety of substances

Common causes of hypersensitivity rxns

Inhaled materials ∙Plant pollens ∙Dander of domesticated animals ∙Mold spores ∙Feces of very small animals (i.e. dust mites) Injected materials ∙Injected venomes ∙Vaccines ∙Drugs ∙Therapeutic proteins Ingested materials ∙Food ∙Orally administered drugs Contacted materials ∙Plant leaves ∙Industrial products made from plants ∙Synthetic chemicals in industrial products ∙Metals

Characteristics of most NSAIDs

Inhibit COX Four A's: Analgesic, anti-inflammatory, antipyretic, antiplatelet Absorbed from stomach, SI Highly bound to plasma proteins Metabolized by liver, excreted by kidney

Corticosteroids

Inhibit expression of adhesion molecules and receptors Decreases transcription rates for IL-6 & IL-1b Suppresses phospholipase A2, COX2, and NO synthase

Biologic effects of Type 1 IFNs

Inhibit viral replication Increase expression of Class I MHC molecules Enhance (viral) antigen expression ot CD8+ CTL Enhance production of Th1 in humans ∙Increase IL-12R expression Enhance NK cell cytotoxicity Inhibit proliferation of many cell types in vitro

IL-10

Inhibitor of activated macrophages and dendritic cells Cellular source: activated macrophages ∙Seems counterintuitive, but could be a balance mechanism, could be different cell populations, etc. ∙Proteins may preferentially stimulate to make IL-10 vs. IL-12 Biologic effects ∙Clear example of a negative regulator ∙Not clear whether different stimuli act on macrophages to produce IL-1o instead of IL-12 or same stimulus induces production of both but w/ different kinetics ∙IL-10 inhibits the production of IL-12 by activated macrophages and dendritic cells →Since IL-12 is an inducer of IFN- γ and promotes innate and cell-mediated immune rxns against intracellular microbes, IL-10 downregulates all of these functions ∙IL-10 inhibits expression of co-stimulators and Class II MHC on macrophages and dendritic cells ∙IL-10 knock out mice develop IBS →May be uncontrolled macrophage activation to enteric microbes

Allylamines

Inhibits squalene epoxidase Decreases ergosterol, increases squalene in the cell membrane ∙Squalene is toxic to the cell Accumulates in skin & nails ∙Effective against dermatophyte infections (ringworm), especially onychomycosis (infection of nails) Terbinafine = representative drug ∙Oral form of terbinafine → nail infections ∙Topical forms → skin infection Side effects - GI upset, headache

Mechanism of action of Echinocandins

Inhibits β-glucan synthase; cell wall β-(1,3)-glucans are not made

Once the T cell is inside the secondary lymph organ

Initial adhesive interactions b/w T cell and dendritic cell

Mechanisms of GVH

Initiated by donor T cells present in graft Secrete cytokines Activate host macrophages, NK cells (Type IV DTH)

Major Features of Chronic Inflammatory Response

Injurious agent persists in tissue for weeks, months, years Cellular response to persistent injury generally consists of macrophages and lymphocytes Granuloma formation occurs upon prolonged macrophage stimulation Tissue necrosis with ingrowth of fibrovascular granulation tissue results in scar formation ∙In any healing response, you will get granulation tissue ∙Granulation tissue = newly made substances in area that has been damaged where you need healing NOTE: persistent neutrophilic exudation is occasionally present in chronic inflammation ∙There are some conditions in body that will consistently produce neutrophils at sites of inflammation ∙Ex: Cystic fibrosis →In lungs, neutrophils are highly prevalent in areas of continual inflammation

Persistent and chronic infections

Invasive pathogens must evade non-specific resistance mechanisms and immune responses ∙*Dependent on organism's gene expression * →if organism senses that nutrients are running out or ATP is limited, it will shut down its gene expression, and makes the organism kind of inactive →the organism will remain in the cell until nutrients are in better supply →i.e. decrease expression (less active) ∙Dependent on changing internal environment of the eukaryotic cell →i.e. limitations of nutrients and energy →Limiting nutrients drives organism into persistent stage Host factors may contribute to pathology ∙Gets activated and not turned off → b/c body cannot clear infection, so leads to chronic inflammation ∙i.e. proinflammatory cytokines ∙i.e. proteases released from immune cells Response to pathogen invasion ∙Acute inflammation (no residual damage) ∙Chronic inflammation (residual scarring) ∙Cellular response - innate →Phagocytes →→→Macrophages →→→Monocytes →→→Neutrophils (PMNs) →Lymphocytes ∙Humoral response - adaptive →Antibodies

Epithelialization

Involves mature epithelial tissue (keratinocytes for skin) and multipotential stem/stromal cells

Actinomyces

Irregular staining gram (+) rods that develop filamentous forms or hyphae (look like fungi) Facultative or obligate anaerobes A. israelii is an important species Colonize upper respiratory tract, GI and female genital tract ∙Not on skin

EBV Serology

It is important to understand this table Note: in Burkitt's Lymphoma and Nasopharyngeal carcinoma, there is a + association with EBV

Is there a worm emergency?

It may occur when a grossly visible worm is recognized by the patient creeping across a body part or emitting from an orifice

Vaccinia vs. Smallpox

Jenner's strategy cannot be applied to most pathogenic viruses because there is no 'safe' counterpart Cowpox and smallpox viruses share some surface antigens ∙Cowpox in humans is usually mild ∙Immunization w/ cowpox induces antibodies against cowpox surface antigens, which can also bind & neutralize the smallpox virus Most viral vaccines used today are killed (or inactivated) or live attenuated

Consequences of PKC-θ Activation

Just know that PKC-θ sets in motion a cascade of events that result in phosphorylation and destruction of IkB and NFkB

B cell lymphomas

KSHV sequences with rare form of AIDS-related B cell lymphomas (body cavity based lymphomas) Lymphomas are co infected with EBV normally

Imidazoles

Ketoconazole, clotrimazole, miconazole & others Non-ketoconazole imidazoles - topical medications ∙Cutaneous & mucocutaneous Candida infections & dermatophyte infections Ketoconazole ∙Tablets, creams & shampoos ∙Cutaneous infections, dimorphic mycoses & Cryptococcus neoformans ∙Side effects - nausea, vomiting, anorexia & occasionally hepatotoxicity ∙Interferes with steroid hormone synthesis & some drug metabolism

Heteroaryl Acetic Acids

Ketorolac (Toradol) Tolmetin (Tolectin) Diclofenac (Voltaren)

Bacterial survival and relationship to disease

Key to survival ∙Recognition of environmental conditions and rapid response (i.e. iron stores or depletion) ∙Alter gene expression under new conditions - favors adaptation and ultimately survival ∙Growth phase of organism →Early log growth vs. stationary growth phase →Most chronic intracellular organisms change gene and protein expression in the stationary growth phase (enhances survival) Note - disease is not the primary objective of the organism

Plague

Killed more than wars, famines, and other pestilences combined Continue to present whenever equilibrium b/w rodents and humans is altered in favor of plague vectors Epidemiology - Yersinia pestis ∙Enzootic in US west of 100th meridian (from ND to TX) ∙Specialized clone of successful enteric pathogen Y. pseudotuberculosis, which has acquired the ability to infect fleas and use them as vectors of transmission Transmission ∙Bites from infected fleas ∙Direct inoculation with body fluids of infected animals ∙Inhaling infected respiratory droplets from animals or humans Clinical features ∙Characterized by necrotizing rash, purpuric skin lesions and gangrene ∙Other features = fever, hemoptysis, dyspnea, chest pain, stridor and peripheral acral cyanosis ∙Endotoxic shock, DIC, severe bronchopneumonia w/ mucopurulent sputum, oliguria, coagulopathy and mental status change may ensure ∙Mortality from untreated plague is 40%, but is virtually 100% in untreated septicemic form ∙Secondary plague pneumonia = hematogenous spread to lung ∙Primary plague pneumonia = direct inhalation of bacilli from coughing human or animal ∙Septicemic plague = results in sepsis syndrome, DIC, MOD and ARDS →Gangrene of fingers and toes or tip of nose caused by small vessel thrombosis may appear in advanced stages Neurologic features - delirium, stupor, sleeplessness ∙Weak, vertigo, staggering gait, slurred speech common ∙Loss of memory is common sequelae in long-term survivors Dx: can be made from lymph node aspirate, sputum, bronchial washes and blood ∙Exhibits bipolar safety pin staining on Wayson stain ∙Other methods = antigen detection, IgM EIA, immunostaining, PCR, DFA to F1 antigen and passive hemagglutiantion Rx: streptomycin, gentamicin, tetracycline, doxy, fluoroquinolones, and chloramphenicol

Strategies to evade phagocytes

Killing or avoiding killing by phagocyte ∙Eluding contact ∙Protection against intracellular killing Interfering with ciliary action Interfering with complement activation ∙Acquire or mimic complement regulators ∙Inhibit complement components ∙Enzymatically destroy complement components Producing iron-binding molecules Blocking interferons

Lyme Disease (LD)

LD is a multisystem disease that occurs in stages and mimics many other diseases LD is currently the most common and frequently reported vector-borne illness in US Etiology - Borrelia burgdorferi is a highly specialized, motile, two membrane spiral-shaped bacterium that lives primarily as an extracellular pathogen ∙Virulence factor is surface proteins ∙Borrelia are thin, elongated, motile bacteria w/ a fragile, fluid outer membrane surrounding the protoplasmic cylinder ∙7-11 bipolar flagella are wrapped around cell cylinder and attached to the poles, allowing Borrelia to stay motile in viscous medium ∙contain a small linear chromosome, are very adaptable, and shuttle b/w hematophagus arthropods and vertebrates Pathogenesis - highly invasive and facilitate invasion by binding host-derived plasmin ∙Outer surface protein - OSP-A is expressed abundantly by Borrelia burgdorferi in resting state in midgut of infected ticks →During ingestion of a blood meal, organisms migrate to tick's salivary glands where they switch from expressing OSP-A to OSP-C →OSP-A is uniform across different isolates, while OSP-C is highly variable hence no protection against previous infection →Has several other outer surface proteins such as flagellin - flagella traverse length of cell body and are hidden beneath outer membrane, help organism to swim in highly viscous media Vector - ixodes scapularis in east and Midwest and Ixodes pacificus in western US ∙Hard bodied, blacklegged ticks w/ 2yr life cycle ∙Reservoir host is white-food mouse for larval and white-tailed deer (principal maintenance host) for adult ticks and wood rats on Pacific coast ∙Grace period - first 48 hours of attachment is required for spirochetes to migrate from gut into salivary glands of infected ticks once feeding commences ∙Note: Many different ticks removed from humans are actually spiders, scabs, lice, beetles, bugs, dandruff or dirt →They only crawl, DO NOT fly or jump Tick removal ∙Grasp tick firmly and as close as possible to skin ∙w/ steady motion, pull tick's body away gently but firmly, w/o jerking, squeezing or twisting from skin using tissue ∙Do not dig for any remaining mouthparts ∙Wash hands w/ soap and water ∙Punch, shave or complete excisional biopsies have been used in difficult cases

Cell types considered in repair

Labile - high rate of loss and replacement (i.e. squamous epithelia and bone marrow hematopoietic cells) → high replacement capacity Stable - do not normally proliferate to great extent, but can after damage (i.e. hepatocytes, osteoblasts, endothelia, fibroblasts, renal tubule cells) Permanent - inability to divide after development and differentiation → cannot regenerate (i.e. CNS neurons)

Diagnosis and Treatment of Non-Spore Forming Gram (+) Bacteria

Laboratory confirmation difficult ∙Must prevent contamination w/ normal flora ∙Must transport in oxygen free container ∙Must culture on enriched media for a prolonged period ∙Consider that staph and strep can be mistaken for anaerobic cocci Treatment ∙*Gram (+) anaerobic cocci are usually susceptible to penicillins and carbapenems* ∙Most infections are polymicrobic so *treat w/ a broad spectrum antibiotic*

Crohn's disease granulomas

Large areas of destruction w/ lots of lymphocytes

Granuloma w/ epithelioid macrophages and lymphocytes

Large cytoplasm, light nucleus = epithelioid macrophages Lymphocytes = dark staining nucleus, little cytoplasm

Clostridia species

Large gram (+) rods (majority) Obligate anaerobes (some aerotolerant) Ubiquitous, in soil/water/air Normal flora in GI tract Usually cause exogenous infections, but occasionally of endogenous origin Toxins important in disease Species: ∙C. perfringens ∙C. tetani ∙C. botulinum ∙C. difficile

Clostridium tetani

Large, Gram positive rods, forms terminal round spores (drum stick shape) Ubiquitous Extremely oxygen sensitive Spores viable in soil for many years; prevalent in manure treated soil, dirty metal or glass *Organism remains localized in wounds but produces a neurotoxin (tetanospasmin)* ∙An A-B toxin ∙*Inactivates proteins that regulate release of inhibitory neurotransmitters (glycine and GABA) ∙Results in unregulated excitation* ∙Toxin *binding irreversible* so recovery dependent on formation of new axonal terminals Vaccine in US ∙Toxoid; induces immunity to the neurotoxin

Cervicofascial actinomycosis

Lesions resemble subcutaneous mycoses Chronic, slowly developing lesions w/ pus and draining sinuses Pus contains colonies of the organism, called sulfur granules (resemble grains of sand that appear yellow or orange

Factors influencing wound healing

Local: ∙Persistent infection or foreign material ∙Inadequate blood supply ∙Excessive movement ∙Irradiation ∙Locally applied drugs, i.e. corticosteroids Systemic: ∙Age - healing slower and less effective w/ increasing age ∙Nutritional deficiencies: i.e. vitamin C, zinc, protein ∙Metabolic disease, i.e. renal failure, diabetes mellitus ∙Catabolic state associated w/ malignancy ∙Systemic drugs, i.e. corticosteroids

C. perfringens: Clinical diseases

Localized cellulitis: gas formation in soft tissue Suppurative myositis: accumulation of pus in muscle planes w/o muscle necrosis or systemic symptoms Myonecrosis: painful, rapid destruction of muscle, systemic spread, high mortality Food poisoning (enterotoxin): ∙Rapid onset ∙Watery diarrhea ∙No fever, nausea or vomiting ∙Self-limiting Necrotizing enteritis: (Beta-toxin dependent) ∙Intestinal stasis, loss of mucosa, formation of necrotic lesions

NSAIDS

Low doses = antithrombotic effects ∙Inhibit thromboxane synthesis in platelets High doses = thrombotic effects ∙Inhibit prostacyclin synthesis

The perivascular mononuclear cell infiltrates associated w/ a DTH rxn consists of:

Lymphocytes Macrophages Endothelial cell activation

Multicentric Castleman's Disease

Lymphoproliferative Disease that is also associated with KSHV

What are MAP kinases?

MAP kinases are a family of serine/threonine protein kinases involved in diverse cellular responses to membrane receptor signaling

Steps of repair process

Macrophages phagocytize necrotic debris and foreign material At edges of damaged area, proliferation of endothelial and fibroblasts Endothelial cells grow into damaged area Capillary formation and fibroblast migration form a loose connective tissue framework → granulation tissue Capillary vessels anastomose to establish blood circulation in the area of healing ∙Vessel differentiation occurs into arterioles and venules ∙Fibroblasts begin producing collagen to give tissue tensile strength Over time, a mature scar consisting of dense collagen is formed ∙In general, the volume of scar tissue is always less than the amount of original tissue it has replaced ∙Clinical implications: scar contraction and loss of function (i.e. skin scarring around joints can produce contractures and immobility)

IL-15

Made by mononuclear phagocytes (and probably other cells types) ∙Made in response to viral infection, LPS and other triggers of innate immunity Structurally homologous to IL-2 IL-15Rα homologous to IL-2Rα ∙Uses the same receptor β and γ chain as IL-2 ∙Do not bind the same receptors b/c α chain confers cytokine specificity Targets and biologic activities ∙T cells: survival of memory T cells ∙NK cells: survival, differentiation and proliferation

Candida

Major opportunistic fungal pathogen The most common species is C. albicans ∙90-100% of mucosal isolates are C. albicans ∙40-70% of isolates from blood stream infections are C. albicans Normal floral in the oral cavity, lower gastrointestinal tract & female genital tract Also found on skin, fingernails & toenails Most infections are endogenous ∙Transmission from the skin of healthcare workers has been documented Yeast in tissue as normal flora Septated hyphae & pseudohyphae seen with invasive disease *Germ tubes* - hyphae-like outgrowth from a yeast cell ∙Produced by *C. albicans* when cultured in serum ∙*Diagnostic test for this strain* C. glabrata - 2nd most common species of Candida ∙Does not form hyphae, pseudohyphae or germ tubes

Sirolimus (rapamycin)

Mechanism of action ∙Binds immunophilins, inhibits calcineurin ∙*Does not block interleukin production* ∙*Instead, blocks T cell RESPONSE to cytokines* ∙Also blocks B cell proliferation and immunoglobulin production ∙Suppresses proliferative responses to CSFs Can be used together with other immunosuppressives Indications similar to cyclosporine Toxicities ∙Profound myelosuppression (particularly thrombocytopenia) →b/c you are blocking growth factor cytokine responses ∙Hepatotoxicity ∙Diarrhea ∙Hypertriglyceridemia ∙Headache

Mycophenylate mofetil

Mechanism of action ∙Inhibits B and T cell proliferative responses in vitro ∙Inhibition of de novo synthesis of purines Usages: ∙Refractory solid organ rejection ∙In combination with prednisone (steroids), as an alternative to cyclosporine or tacrolimus ∙Steroid refractory GVH ∙Lupus nephritis, RA, some dermatologic disorders Toxicities ∙Gastrointestinal disturbances (nausea, vomiting, diarrhea, abdominal pain) ∙Myelosuppression (b/c anti-proliferative agent)

Glucocorticoids

Mechanisms of action ∙Reduces size and lymphoid content of lymph nodes and spleen ∙No effect on proliferating myeloid and erythroid stem cells in the bone marrow ∙Interfere with cell cycle of activated lymphoid cells ∙Inhibit production of inflammatory mediators (PAF, leukotrienes, prostaglandins, histamine) ∙Monocytes and neutrophils: diminished chemotaxis and impaired bacteriocidal and fungicidal activity, inhibition of NO synthase, does not impair phagocytosis ∙Inhibits IL-1 (also, IL-3,IL-3, IL-4, IL-5, IL-8, and TNF-α) ∙CMI more affected than humoral Indications: multiple Toxicities: multiple ∙Musculoskeletal (bone mineral loss) → osteoporosis ∙Fluid/electrolyte disturbances (weight gain, fluid retention) ∙Dermatologic (thin, fragile skin, impaired wound healing) ∙Psychologic (insomnia, psychosis) ∙Endocrine (diabetes mellitus)

Herpes keratitis

Mediated by autoimmune response of a viral protein (autoimmune disease of the eye) Could be the result of molecular mimicry by HSV ∙Viral protein contains same sequence as a corneal cell protein and antibody on viral protein recognizes this protein on corneal cells *Leading cause of blindness in developing countries* from corneal clouding Types of lesions: ∙Clear vesicles on a erythematous base ∙Pustules become ulcers which become crusted lesions ∙Example with chicken pox →Considered infectious until last set of pustules crust over →It becomes infectious because virus can get aerosolized and therefore other people can inhale it →Virus itself resides in pustules ∙The lesions are similar for HSV and VZV ∙The fluid inside the lesions contain infectious virus

Attachment

Mediated by surface glycoproteins of enveloped viruses ∙HA of influenza ∙Gp120 of HIV Mediated by capsid proteins of naked virions Important determinant of viral tropism ∙Tropism refers to the ability of a virus to infect a particular cell type

Non-Spore Forming Gram (-) Anaerobes

Medically important species: ∙Bacteroides ∙Fusobacterium ∙Parabacteroides ∙Porphyromonas ∙Prevotella ∙Veillonella →Gram (-) cocci

Steps in T cell activation

Membrane events ∙Antigen/MHC binding to TCR ∙Co-receptor binding to ligands (CD4:MHC Class II) ∙Co-stimulatory events (CD28: CD80/86) Cytoplasmic signalling events ∙Begins with receptor-associated tyrosine kinases, which regulate PLCg Activation of transcriptional factors ∙NFAT ∙NFkB ∙AP-1 →c-fos →c-jun Gene expression ∙CD40L ∙IL-2 ∙IL-2R

IL-2: Clinical Usage

Metastatic renal cell carcinoma Refractory malignant melanoma Toxicities include: ∙Vascular leakage ∙Severe hypotension

Laboratory Diagnosis of Actinomyces

Microscopic ∙*Microcolonies of Actinomyces called sulfur granules are in sputum, pus from draining sinuses, etc → diagnostic* ∙Gram (+) bacilli seen when sulfur granules are crushed b/w slides Culture ∙Growth is low, may take up to 2 weeks ∙Specimens should be grown anaerobically ∙Just determine if Actinomyces, species differentiation too time consuming

Keratinocyte behavior

Migration ∙Basal cells must loosen adhesion to original ECM and adjacent cells ∙Must migrate over provisionary matrix while former adjacent cells proliferate to replace them ∙Migration characterized by changing keratin protein expression ∙Mediated by factors released by other cells →TGFb (transforming growth factor beta) stimulates MMP (matrix metalloproteinase) expression →EGFs (EGF, TGFa) cause migration, proliferation →FGFs (FGF2 from fibroblasts) →Cytokines (IL-1, IL-6, TNFa) Proliferation ∙First KC layer to cover wound begins proliferating ∙Responds to available stimuli: EGF, TGFa, KGF, IGF-1, all working with MMPs →Synergy between GFs, provisional ECM and integrins on cells ∙Once wound is covered, proliferation ceases ∙Stratification begins to form normal tissue

Clostridium difficile

Minor component of normal intestinal flora Nosocomial pathogen in patients on antibiotic therapy ∙*Antibiotics eliminate normal flora; allow overgrowth of C. difficile* ∙Outpatient: medication that decrease gastric acid Responsible for antibiotic-dependent gastrointestinal disease ∙*Ranges from a relatively mild diarrhea to severe pseudomembranous colitis* *2 toxins* - both produced during clinical disease ∙Enterotoxin (toxin A) →Chemotactic for neutrophils; induces cytokine production →Increases permeability of the intestinal wall with hypersecretion of fluid ∙Cytotoxin (toxin B) →Induces depolymerization of actin with loss of cellular cytoskeleton

Agents used to minimize side effects of NSAIDs

Misoprostol (Cytotec) ∙PGE1 analog ∙Used to suppress gastric ulceration ∙Used with patients on chronic treatment with NSAIDs agents ∙NOTE: has abortifacient property and therefore NOT to be used with pregnancy

Types of fungi

Mold: filamentous form of fungi ∙Bottom left image, hairy looking Yeast: oval-shaped, single-celled form of fungi ∙Can resemble bacteria on agar plate or slant, but tend to be much bigger than bacteria ∙Bottom right image Dimorphic fungi: fungi that can grow both as a mold and as a yeast ∙Not all fungi can do this, but there is a good deal that can Dematiaceous fungi: black or brown pigmented fungi ∙Phaeohyphomycosis - infections caused by dematiaceous fungi →coming more common as opportunistic pathogens

Angiogenesis in disease and death

Most blood vessels are quiescent in adulthood Angiogenesis occurs in cycling ovary and in the placenta *Endothelial cells*: can divide in response to hypoxia and inflammation ∙Sometimes the stimulus is excessive ∙*Angiogenesis can occur in malignant, ocular (i.e. diabetic retinopathy) and inflammatory disorders*

Clinical infections: Important points

Most infections are endogenously acquired ∙Clostridium is an exception Infections are often polymicrobial ∙Several different types of anaerobes ∙Mixture of anaerobes and facultative organisms Infections often involve abscesses Foul odor and gas suggest anaerobes

Colonization

Mucosal surfaces Sites of injury Resists cilia/mucus clearance mechanisms → cilia cannot move organism out, mucous clearance compromised Tissue tropism - Certain sites safer for microbes than others ∙i.e. CNS, joints, testes, placenta ∙Reasons: less lymphocyte surveillance and lower access of antibodies and complement →If inflammation is induced though, lymphocytes, macrophages and antibodies can be delivered - site loses privilege

Live attenuated viral vaccines

Mutated so that it has reduced ability to grow in human cells ∙No longer pathogenic in humans ∙Usually made by growing the pathogenic viruses in cells from a non-human species →Select for variants that grow in the non-human host →But less fit to grow in the human host Examples of live attenuated viral vaccine ∙Measles ∙Mumps ∙Sabin (polio) vaccine - one of the original polio vaccine ∙Yellow fever ∙Live attenuated influenza-delivered intranasally ∙Varicella (chicken pox) ∙Rotavirus-delivered orally Advantages of live attenuated viral vaccine ∙Better immunity because vaccine actually produces a limited infection →Generally not enough to cause disease in immunocompetent ∙Can spread the attenuated virus to contacts ∙"herd immunity": phenomenon whereby those people who have no immunity against a particular pathogen are largely protected because the majority of the population is immune Disadvantages of live attenuated viral vaccine ∙Can cause disease in immunosuppressed or immunodeficient individuals →VAPP (vaccine associated paralytic polio): →→→Reason oral Polio vaccine (OPV) is no longer recommended (now only given inactivated) →Varicella →→→Vaccine contraindicated in patients with evidence of substantial defects in cellular (T cell) immunity →Rotavirus →→→Rotavirus vaccine: precautions for altered immunocompetence ∙Reversion to wild type or pathogenic virus

What is NFAT?

NFAT is a transcriptional factor when phosphorylated, it is cytoplasmic and inactive when dephosphorylated, it moves to nucleus and influences transcription Calcineurin and immunosuppressive Tx ∙Cyclosporine A: complexes with cyclophilin ∙FK506 (tacrolimus): complexes with FKBP ∙both complexes inhibit calcineurin

Contraindications for acetaminophen

NOT FOR INFLAMMATORY CONDITIONS ∙Can use for analgesia, adjunct w/ other anti-inflammatory agents Use w/ caution w/ liver disease

Host response to viruses

Natural immunity against viruses: Role of IFNS and NK cells ∙Interferons (α and β) are very important in innate resistant to viral infection ∙Direct effects on the virus: →Inhibition of viral protein synthesis →Degradation of viral RNA →Inhibition of viral gene expression ∙"Indirect" effects of IFN α/β on immunity →Causes sequestration of lymphocytes in lymph nodes, maximizing opportunity for interaction w/ microbial antigens →Increase cytotoxicity of NK cells, macrophages and CTL →Promote differentiation of naïve Th0 cells to Th1 →Increases Class I MHC expression →*Thus, the type I (α and β) interferons are very important bridges b/w innate and acquired immunity* ∙NK cells →Detectable w/in 2 days of infection →Incredibly response to many cytokines →→→Type I IFNs →→→IFN-γ →→→IL-2 →→→IL-15 →→→Others (IL-15) →Recognize target cells via KARs and KIRs →→→Recognize lytic activity →Lysis proceeds →→→Perforin/granzymes →→→ADCC (NK cells have Fc receptors for IgG) ∙Macrophages act on viruses at 3 levels →Phagocytosis of virus and virally-infected cells →Killing of virally infected cells →Release of antiviral molecules →IFN-α →TNF- α →NO Specific immune responses to viral infection ∙Virus-specific antibodies control viruses when they are EXTRACELLULAR ∙Major mechanism for prevention of viral spread b/w cells and tissues ∙Important in restricting viremia (especially IgG) ∙IgA at mucosal surfaces: prevents re-infection (remember that viruses often enter vial mucosal surfaces) ∙Mechanism of antibody action: →Neutralization of viral infectivity →Bind to and block viral attachment structures →Important in re-infection scenarios →Activation of complement and destruction of enveloped viruses →Virolysis →Probably not major clearance mechanism (complement deficiencies not associated w/ increased susceptibility to viral infection) →Killing of infected cells (INTRACELLULAR virus) →→→Antibody and complement →→→ADCC CD4+ T cells ∙Antiviral antibody production is usually T-dependent (CD4+ Th1 cells) ∙Class switching and affinity maturation ∙Help in the induction of CD8+ CTL ∙Production of cytokines (IL-2, IFN-γ) ∙Recruit and activate macrophages (CD40L and IFN-γ) CD8+ T cells ∙KILL VIRALLY INFECTED CELLS IN A CLASS I MHC-RESTRICTED, ANTIGEN-SPECIFIC MANNER →Kill via perforin/granzymes →Induction of apoptosis: Fas/FasL →Cytokine production

Portals of pathogen entry

Natural or acquired openings, leading to internal organs

Side effects of ketorolac

Nausea Dyspepsia GI pain Drowsiness

Regulation of the repair process

Neovascularization (angiogenesis) ∙Pre-existing vessels bud or sprout to make new vessels ∙Steps in process of new vessel formation: →Proteolysis of parent vessel basement membrane to allow sprouting →Migration of endothelial cells toward stimulus →Proliferation of endothelial cells behind migrating edge →Maturation of endothelial cells and remodeling into tubes →Recruitment of pericytes for small vessels (capillaries) and smooth muscle cells for large vessels →→→Needed to support new vessels ∙NOTE THAT ALL ABOVE STEPS DEPEND ON VASCULAR CELLS, GROWTH FACTORS AND ECM INTERACTIONS Growth Factors ∙Vascular endothelial growth factor (VEGF) ∙Transforming growth factor-β (TGF-β) ∙Platelet-derived growth factor (PDGF) ∙Epidermal growth factor (EGF) ∙Fibroblast growth factor (FGF) ∙Other regulators (cytokines) →TNFα and IL-1 are fibrogenic cytokines, promote migration and proliferation of fibroblasts in granulation tissue Extracellular matrix proteins ∙Proteoglycans - heparin sulfate, chondroitin sulfate, dermatan sulfate, syndecan ∙αvβ3 integrins - critical for maintaining new blood vessels ∙Matricellular proteins (i.e. thrombospondin 1, tenascin C) - destabilize the cell-matrix interactions to promote angiogenesis ∙Proteases (i.e. plasminogen activators, matrix metalloproteases) - important in remodeling during endothelial cell invasion)

Infection control: Anthrax

No person-to-person transmission Standard barrier isolation precautions employed Requires biosafety level II operation

Virus-Host Interactions: Non-productive Infection

No progeny are produced Cells are nonpermissive for the virus Types of nonproductive infection ∙Abortive →Host cell cannot support viral replication →Viral genome is lost ∙Latent infection →The virus is dormant within the host cell and is protected →The viral genome is maintained →Viral transcripts may be detected; few or no viral proteins are expressed →→→Immune response does not recognize that the cell is infected →Occurs in DNA or retroviruses →Reactivation of a productive infection is possible (but does not always show symptoms) →Examples of viruses causing latent infections

Examples of evasion and representative bacteria

No triggering of oxidative burst - Legionella Modify or abort normal route of phagosome maturation - M. tuberculosis Diversion of phagosome to another pathway and resist phagolysosomal fusion (ie, to Golgi or ER) - Chlamydia and Legionella Resist lysosomal degradation - Coxiella burnettii and Salmonella ∙However, cannot survive in activated macrophage Escape from phagosome - Listeria monocytogenes, Shigellae, and Rickettsiae ∙However, pathogen now subjected to MHC class I pathway (cytosolic) of antigen processing and presentation

Non-steroidals and other anti-inflammatories

Non-steroidal anti-inflammatory drugs (NSAIDS) and Aspirin Specific COX-2 inhibitors (i.e. Celebrex) Nutrition - i.e. vitamins D, E, C and folic acid are anti-inflammatory ∙Omega 3 fatty acids ∙Resveratrol (red wine)

Detecting fungal antigens & metabolites

Not all tests are commercially available but may be used in reference laboratories or research setting Rapid, sensitive & specific diagnostic tests would allow for more timely administration of correct therapy ∙Some enzyme immunoassay (EIA) & latex agglutination (LA) tests are currently available

Tacrolimus

Not chemically related to cyclosporine, but similar MOA Mechanism of action: ∙Tacrolimus binds to FK-binding protein and complex blocks calcineurin ∙NFAT activation is blocked Same indications as cyclosporine Toxicities ∙*Nephrotoxicity* ∙Neurotoxicity ∙Hyperglycemia ∙Hypertension ∙Hyperkalemia ∙GI complaints

Inhibition of viral replication by antivirals

Not every step can be prevented for every virus during antiviral therapy; something that works for flu wouldn't work for HIV Disruption of viral particles ∙Enveloped viruses can be inactivated by detergent-like agents ∙Nonoxynol-9 inactivates HSV and HIV (present in birth control jellies) ∙Citric acid incorporated into tissues can help prevent transmission of Rhinoviruses (cold viruses that are acid labile) Attachment inhibition ∙Block the binding site of viral attachment proteins (VAPs) →Neutralizing antibody that inhibits protein binding to the receptor ∙Receptor antagonists →Peptides or sugar analogues of receptor or VAP →Example - peptides have been designed to inhibit attachment of HIV VAP (gp120) to its co-receptor (chemokine receptor) Entry/uncoating inhibition ∙Compounds bind capsid proteins and receptor binding site →Inhibit the dissociation of capsid proteins ∙Amantadine and rimantadine inhibit the influenza virus →Block the proton channel (M2) in the viral envelope →Inhibits the dissociation of the nucleocapsid protein (N) from the viral matrix protein (M1) ∙Enfuvirtide inhibits virus-cell fusion mediated by HIV envelope glycoprotein (gp41) Inhibiting the transcription of viral mRNA ∙Difficult without affecting the host cell mRNA synthesis →DNA viruses use host cell enzymes to synthesize viral mRNA →Viral RNA polymerases may be too similar to host cell polymerases →→→Can't selectively inhibit the viral enzyme →Viral RNA polymerases have a high mutation rate →→→Generate drug-resistant viruses Inhibiting the translation of viral proteins ∙Viral protein synthesis is a poor target for antiviral drugs →Viruses often use host enzymes, transcription factors, ribosomes, etc. to transcribe/translate viral genes/proteins Potential mechanisms to inhibition of viral protein synthesis ∙Interferon-alpha inhibits viral protein synthesis →Hepatitis C virus and HPV ∙Oligonucleotides can inhibit translation of viral mRNA →Use specific sequence that binds to a viral sequence to inhibit translation of that transcript →Can use it as an antiviral ∙Block post-translational modifications of viral proteins →Inhibit cleavage of a polyprotein →Inhibit glycoprotein processing →→→Disrupt functions of viral attachment and fusion to glycoproteins Genome replication ∙Targets →DNA polymerases of herpesviruses →Reverse transcriptase (RT) of HIV ∙Nucleoside analogues - can introduce mutations and inhibit the infectivity of the virus →Modification of either the base of the sugar moiety →Viral polymerases are more error-prone →Modified bases lacking a 3'-OH block chain elongation →Inaccurate base pairing introduces mutations into the genome of viral mRNA Inhibition of assembly and release ∙HIV protease inhibitors →HIV protease activity I required for viral assembly →Inhibitors prevent maturation of the viral particle into an infectious virus ∙Zanamivir and oseltamivir inhibit neuraminidase activity of influenza virus →Required for release of ne viral particles

Phenylbutazone (Butazolidin)

Not really used anymore Action: analgesic (inferior to aspirin for non-rheumatic pain), anti-inflammatory (most prominent), antipyretic VERY TOXIC Uricosuric similar to aspirin Uses = acute gout and rheumatoid arthritis Mechanism of Action: inhibitor of COX Metabolism ∙98% plasma protein bound ∙Competes w/ NSAIDs, warfarin, oral hypoglycemic, and sulfonamides Side effects ∙10-45% experience, 10-15% discontinue ∙Epigastric pain, nausea, emesis and skin rashes most frequent ∙Gastric ulceration ∙CNS effects (vertigo, insomnia, euphoria, nervousness) ∙Skin rashes, allergic reactions, nephritis, hepatitis, aplastic anemia, agranulocytosis Contraindications ∙Cardiac, hepatic or renal dysfunction ∙Blood dyscrasias ∙Promotes retention of Na+ and CI- with water leading to cardiac decompensation and pulmonary edema in some patients

Langhans cells in TB granulosa

Note: caseating necrosis Langhans cells are the giant cells w/ multiple nuclei around outside ∙Horse-shoe typing winging to nuclei

Composition of viruses

Nucleic to a genome ∙DNA or RNA (not both) ∙Viral core is the genome and its associated enzymes The protein shell is called a capsid that surrounds the core ∙Can be helical or icosahedral/icosadeltahedral (spherical, crystal-like) ∙The nucleocapsid is the core plus the capsid ∙Structural proteins = capsid proteins ∙Enzymes and nucleic acid binding proteins = core proteins ∙Some viruses are only the nucleocapsid, others have an envelope as well

Obligate (strict) anaerobes

O2 is toxic

Uncoating

Objectives of uncoating: ∙Get rid of the capsid ∙RNA goes to the cytoplasm →Uncoating usually coincides with entry into the cell ∙DNA goes to the nucleus and enters through the nuclear membrane ⁿUncoating doesn't occur with entry, but the mechanism of uncoating is the same, just at a different membrane Involves the dissociation of capsid proteins Triggers for uncoating include: ∙Binding to a receptor ∙Change in pH ∙Proteolytic degradation

Invasion

Obligate intracellular pathogens must invade ∙NOT FREE LIVING ORGANISMS → NEED SOMETHING FROM OUR CELL (i.e. nutrients like AAs, ATP, etc.) ∙Will enter our eukaryotic cells, and start to syphon our resources ∙This stresses our mitochondria → leads to ROS creation and oxidative damage Invasion depends on eukaryotic cell and bacterial cell properties Endocytic response may result in engulfment

Side effects of naproxen

Occult blood loss less than aspirin CNS - drowsiness, vertigo, headache, fatigue, ototoxicity GI disturbance - emesis, dyspepsia, gastric bleeding Pruritus (not w/ ibuprofen)

Acute graft rejection

Occurs days to years after transplant, usually with tapering or termination of immunosuppressive treatment The immunologic mechanism of acute graft rejection can be antibodies (humoral), T cells (cell-mediated) or both! ∙Cell-mediated more often Acute cellular (T cell mediated) rejection is VERY WELL controlled by immunosuppressive therapy ∙Type I-tubulointerstitial pattern is characterized by extensive interstitial inflammation and inflammation of tubules (tubulitis). Cellular infiltrates include CD4+ and CD8+ cells, which express CD25 (the IL-2Rα chain) ∙Type II-vascular pattern is characterized by inflammation of vessels and swollen endothelium (endothelitis) →Lymphocytes can be seen between the endothelium and the vessel wall ∙ Type III: Type II plus vascular wall necrosis Acute antibody-mediated rejection ∙Damage to the glomeruli and small vessels ∙Inflammation of the glomeruli and peri-tubular capillaries

Cross-linking of surface bound IgE

Occurs during subsequent exposure to antigen Release of mediators in two waves ∙Immediate due to mast cell degranulation ∙Late due to de novo synthesis

Chronic rejection

Occurs months-years after transplantation While immunosuppressive therapy has controlled acute graft rejection, chronic rejection has emerged as an important part of graft failure ∙Seeing much more chronic rejection now b/c of how good we have gotten at controlling acute rejection In kidneys, characterized by: ∙Slow rise in serum creatinine (over 4-6 months) ∙*Dominated by vascular changes* →Intimal thickening w/ inflammation →Glomerulopathy, w/ duplication of the basement membrane probably secondary to chronic endothelial injury →Peritubular capillaritis (inflammation of tubules) w/ multilayering of the peritubular capillary basement membranes ∙*Interstitial fibrosis* →Due to constant cycle of injury-repair-injury ∙*Tubular atrophy,* loss of renal parenchyma Ultimately results in: ∙Ischemia ∙Causes loss of function

Granulomatous hypersensitivity

Occurs when antigen is not cleared Persistent T cell activation and release of cytokines Promotes differentiation of macrophages into epithelioid cells, which secrete TNFa Some fuse to form multinucleate giant cells

Live natural viral vaccines

One of the first 'vaccines' used material from dried pustules of people who got 'mild' smallpox ∙Widely used in the 18th century ∙Sometimes successful ∙Sometimes induced lethal smallpox Live natural viral vaccines Jenner used dried pox from milkmaids (coxpox) ∙Milkmaids either didn't get smallpox or only get mild cases ∙Vaccinia or vaccination ∙Example of a live natural vaccine ∙Protects against smallpox

Products of mast cell activation

One of the prime products = histamines Get release of cytokines as well as production of new cytokines

Virus-Host Interactions: Immortalizing or transforming infections

One or a few viral genes are expressed; non-productive infection Immortalized cells may or may not become tumor cells ∙Transformed cells are immortalized ∙Immortalized cells over time may pick up mutations that lead to oncogenesis Viral genomes usually integrate into the chromosome in transforming infection Cells are semi-permissive for the virus Mechanisms of transformation ∙Inactivate growth-regulatory proteins →p53 →Retinoblastoma gene product (RB) - Normally these help control the cell cycle, but when inhibited you get a stimulation of cell growth which leads to immortalization ∙Provide or up-regulate the genes involved in cell progression through the cell cycle Possible consequences of transformation ∙Uncontrolled cell growth ∙Increased growth rate ∙Alteration of morphology and metabolism →Decreased requirement for serum growth factors →Alterations in cell surface components →Increased metabolic rate ∙Loss of contact inhibition of growth

Celecoxib (Celebrex)

Only COX2 inhibitor approved by FDA Actions: anti-inflammatory, analgesic, antipyretic ∙No anti-platelet action ∙Makes it much safer in many respects Metabolism ∙Absorbed following oral admin ∙Peak plasma levels - 3 hours ∙Steady state reached - day 5 ∙97% plasma protein bound ∙Metabolized by P450 (inactive metabolites) ∙Excreted in feces and urine Side effects ∙GI ulceration, bleeding, and perforation ∙Lower incidence than other NSAIDs ∙*May cause premature closure of the ductus arteriosus* ∙Should not be used in pregnancy Contraindications ∙Sulfa allergy ∙PREGNANCY

Actinomycosis: Clinical Considerations

Opportunistic and always endogenous Follows trauma of mucosal surface of mouth or lower GI tract Chronic granulomatous lesions, that become suppurative and form abscesses connected by sinus tracts Infections currently uncommon and usually polymicrobial Manifestations ∙Cervicofascial: follows dental surgery or disease (*poor oral hygiene*) ∙Abdominal: follows GI surgery or rupture to bowel ∙Thoracic: starts as lung infection due to aspiration → other tissue ∙Pelvic secondary infection or associated w/ intrauterine device

Characteristics of Candidiasis

Organisms can infect any organ system ∙Especially kidney, brain, liver, skin, eye Serious complication in compromised patient; often fatal AIDS patients ∙Oral thrush or esophagitis ∙Recurrent vaginal candidiasis Complication following: ∙Transplants (liver, kidney, bone marrow) ∙Abdominal surgery (peritonitis) ∙Cardiac surgery (endocarditis)

IL-2

Originally called T cell growth factor ∙Principal cytokine response for progression of activated T lymphocytes from the G1 to S phase of the cell cycle in vitro ∙"Growth, survival and differentiation factor for T lymphocytes, and plays a major role in regulation of T cell responses through it actions on regulatory T cells →Tregs are the only population of cells in the body that absolutely requires IL-2 →Knockout causes autoimmune disorders Produced mainly by CD4+ helper T cells (lesser degree by CD8+ cells) early in response to antigen activation (in the presence of co-stimulation) ∙Co-stimluation is required ∙Production is transient Functions in autocrine and paracrine manners Biologic activity ∙*Autocrine growth factor for T cells* →Also induces expression of Bcl-2 (anti-apoptotic) →Induces expression of IFN- γ and IL-4 ∙Stimulates the growth of NK cells and enhances their cytolytic function ∙Growth factor for human B cells and as a stimulus for antibody synthesis ∙Maintenance (survival and function) of CD4+ regulatory T cells (controlling immune responses) →Gene known out studies in mice have shown that the primary NON-REDUNDANT function of IL-2 in vivo is suppression of T cell responses →Knock out mice (Il-2 -/-, IL-2Rα -/-, IL-2Rβ -/-) develop lymphadenopathy and T cell mediated autoimmunity →Suggest that growth factor function of IL-2 may be shared by other cytokines (example of redundancy)

Newer vaccines: HPV

Overall incidence of HPV among US women 14-59: 26.8% ∙JAMA. 2007 Feb 28;297(8):813-9. Quadrivalent vaccine (types 6, 11, 16, and 18) licensed in Sept. 2006 Prevents or reduces incidence of ∙HPV-induced cervical cancer ∙Cervical precursor lesions (dysplasia) ∙vaginal and vulvar cancer precursors ∙Anogenital warts ∙Anal cancers and anal intra-epithelial neoplasia Recommended as routine vaccination for girls 11-12 ∙3 doses ∙Can be started as early as 9 yrs. ∙ACIP recommended routine vaccination for boys in October, 2011

Inflammation Factors

PGE2 and PGI2 ∙Cause erythema, edema, increase local blood flow

Hematological functions of prostaglandins

PGI2 inhibits aggregation (anti-thrombogenic effects) TXA2 induces platelet aggregation (thrombogenic effects) Both of these things are products of the same enzyme

Tyrosine kinases in T cell activation

PTK: protein tyrosine kinase ∙enzyme that phosphorylates tyrosine residues by transferring terminal phosphate group from ATP to hydroxyl group of tyrosine tyrosine phosphorylation regulates: ∙protein-protein interactions ∙enzymatic activity in T cell activation: two key PTKs ∙src family: lck (p56lck) ∙ZAP70 (zeta associated protein, 70kDa) PTKs and resting T cell surface

Use of aspirin

Pain Inflammation Fever (pyrogen-induced and CNS response) Cardiac conditions to reduce blood clotting

Use of Diflunisal

Pain Inflammation →Osteoarthritis →Rheumatoid arthritis

How much helminthiasis is there in the world?

Parasitic diseases cause 3% of food-borne illnesses Parasitic diseases are also responsible for the largest single category of reported drinking water (35%) and recreational water (50%) outbreaks in US Parasitic diseases often go undiagnosed, as the tests are not requested by health care providers

Parasitism

Parasitism = way of life in which one species gains its livelihood at the expense of another Parasites are the under continually assault the body, while constantly dodging the immune system ∙They are able to shuffle surface proteins rapidly, thereby escaping recognition by immune system

Drug Rxns that are Type II Hypersensitivities

Partial list of drugs that can cause type II hypersensitivity disorder by attaching to and modifying a host cell surface: ∙Penicillin ∙Quinidine (drug used to treat cardiac arrhythmias) ∙Methyldopa In each case, the chemically reactive drug binds to cell surface components (RBC or platelets) and creates new 'foreign' epitope IgM/IgG antibody generated In the case of penicillin, the penicillin-modified RBC acquire a coating of C3b as a side effect of complement activation that the bacterial infection induced ∙Facilitates phagocytosis by macrophages Macrophages process and present the penicillin-modified protein to CD4+ T cells ∙CD4+ differentiate into Th2 ∙Stimulate B cells to make antibody to penicillin-modified epitope Antibody causes destruction of drug-bound erythrocytes by: ∙Complement mediated lysis ∙Phagocytosis and destruction of macrophages, neutrophils (via FcR)

Newer therapies for chronic inflammation

Pentoxifylline and thalidomide suppress the release of TNF-alpha from phagocytes Infliximab, etanercept, and adalimumab block TNF-alpha, blocks the protein's activity

Morphology of a delayed type hypersensitivity rxn

Perivascular mononuclear cell infiltrates Consists of: ∙Lymphocytes ∙Macrophages Endothelial cell activation

Dysentery

Perpetual purging of mucus, blood and purulent stools w/ tenesmus and griping (i.e. amobiasis) Associated w/ invasion/inflammation

Transmission of parasites

Person-to person, i.e. amebiasis Food-borne, i.e. cyclospora Infected pets, farm and lab animals, i.e. cryptosporidium Contaminated water, i.e. Giardia Sexual practices, i.e. Giardia Fecally contaminated fomites, i.e. Crytosporidium Contact w/ diaper age children, i.e. Giardia

Resolution

Phagocytosis by macrophages of dead cells and debris → original tissue architecture intact Occurs when there is little tissue destruction (i.e. lobar pneuomonia) ∙Early stages result in pus filling the alveolar spaces but w/o destroying alveolar walls ∙w/ proper treatment and w/ clearance by macrophages, the spaces clear w/ no damage to alveolar walls

Mechanism #1: Opsonization and complement and Fc-receptor mediated phagocytosis

Phagocytosis is a prominent mechanism for removal of cells coated w/ antibodies ∙Cells opsonized by antibodies are recognized by FcγR on the surface of phagocytes ∙Similarly, deposition of specific IgG or IgM on a cell surface recruits complement via classical pathway When antibodies (IgG or IgM) are deposted on the surface of cells, complement is activated ∙Complement activation generates C3b and C4b on target cells ∙Phagocytes have receptors for both IgG (FcγR) and C3b (and C4b) ∙Binding via either (or both) receptors results in phagocytosis of the opsonized cell Complement activation also leads to formation of membrane attack complex ∙Disrupts membrane integrity ∙Drills holes in lipid bilayer ∙Osmotic lysis Antibody-dependent cellular cytotoxicity (ADCC) can also play a role in Type II hypersensitivity ∙Cells coated w/ low levels of IgG can be killed by a variety of effector cells ∙Effector cells bind to the antibody-coated target cell via FcγR →Monocytes →Neutrophils →Eosinophils →NK cells ∙In ADCC, cell lysis proceeds w/o phagocytosis

Three different mechanisms for Type II hypersensitivity

Phagocytosis mediated by opsonization (via complement or antibody) Complement and Fc-receptor mediated inflammation Antibody mediated cellular dysfunction (i.e. myasthenia gravis)

PI3 kinase in T cell activation

Phosphorylates PIP2 to generate PIP3 PIP3 required for activation of: ∙PKB ∙Akt (regulates apoptosis, promotes survival of activated T cells) PIP3/Akt also triggered by: ∙CD28 ∙IL-2R Closely linked is activation of mTOR (mammalian target of rapamycin) ∙Serine/threonine kinase ∙Stimulates protein translation ∙Cell survival and growth ∙Rapamycin inactivates mTOR and is used to treat graft rejection

Consequences of ZAP-70 Activation

Phosphorylation of scaffold proteins Recruitment of an adaptor protein Phospholipase C is recruited to the membrane by binding to PIP3 (generated by action of PI3 kinase on PIP2) ∙PLC recruited to complex and phosphorylated by Itk (tyrosine kinase) ∙Activation of PLC requires a co-stimulatory signal ∙Itk (a tyrosine kinase) contain multiple binding domains including PH ∙Itk is directed to plasma membrane by binding of PH domain to PIP3 ∙Activation of the PI3 kinase probably is the result of binding of CD28 to CD80/86 (co-stimulation), TCR and IL-2R binding ∙Itk phosphorylated and activated by p56lck

Enolic acids

Piroxicam (Feldene) Phenylbutazone (Butazolidin)

Cross-talk throughout wound healing

Platelets, immune cells, endothelial cells, keratinocytes produce signaling molecules w/ autocrine and paracrine functions Early on, KC (adjacent to wound) → chemokines → attract PMNs & immune cells PMNS → IL-6 → keratinocytes to migrate and proliferate IL-1 ∙Autocrine - migration and proliferation ∙Paracrine - fibroblasts to produce KGF TNF- α ∙Autocrine - migration ∙Paracrine - fibroblasts to produce FGF → increasing ECM production TGF-β - fibroblasts & myofibroblasts → granulation tissue All activated cells (EC, platelets, macrophages, fibroblasts) → VEGF for angiogenesis

Stains for clinical fungal specimens

Potassium hydroxide (KOH) preparation ∙Chitin & complex polysaccharides are not destroyed by alkali treatment, so it makes it easier to visualize while degrading other tissues Calcofluor white (can be combined with KOH) ∙Fluorescent stain *Gomori's methenamine silver* ∙Very useful ∙Staining makes it very easy to see the fungal structure Gram stain (fungi often appear gram +) General histological stains include Giemsa, Periodic acid-Schiff (PAS) & Hematoxylin & Eosin (H&E)

Lack of response to antibiotics is viewed as justification for more antibiotics rather than a reason to reconsider dx of LD

Potential sources of confusion & anxiety ∙Labeling pts as having chronic illness ∙Acceptable of sick role ∙Assumption of disabled self-image ∙Greater imitator ∙Open-ended definition ∙Seronegative LD ∙Missed Dx - true disease may progress ∙Myth - LD is incurable/is forever ∙Poor reputation of tests ∙Slow resolution of complaints ∙Infection is acquired in good neighborhood while at work or play

Triazoles

Preferred to imidazoles b/c of greater specificity for the fungal cytochrome P-450 enzyme than imidazoles → fewer side effects than ketoconazole ∙Nausea, vomiting, diarrhea, occasionally liver abnormalities Fluconazole, itraconazole, voriconazole, posaconazole & others Broad spectrum of activity ∙Candidiasis (cutaneous & invasive), dermatophytes, endemic mycoses, Cryptococcus neoformans & Aspergillus infections

Graft rejection is an immune rxn

Prior exposure to cells expressing donor MHC molecules leads to accelerated graft rejection ∙If previously immunized to donor antigens (memory), the rejection rxn is faster The ability to reject a graft rapidly can be transferred to a naïve individual by lymphocytes from a sensitized individual ∙Conclusion - graft rejection is mediated by lymphocytes Depletion or activation of T lymphocytes by drugs or antibodies results in reduced graft rejection

Tumor necrosis factor (TNF-α)

Pro-inflammatory cytokine Principal mediator of the acute inflammatory response to gram (-) bacteria (and other infectious microbes) ∙Systemic complications of severe infection (sepsis or septic shock) Major source: activated mononuclear phagocytes ∙Also produced by activated T cells, NK cells, mast cells Major inducer: LPS ∙Production augmented by interferon-γ (b/c interferon-γ activates macrophages, and activated macrophages make TNF- α) Biologic effects ∙Activates endothelial cells (important in sepsis) →Expression of adhesion molecules such as selectins and VCAM-1 and ICAM-1 (binds neutrophils, then monocytes and lymphocytes) →→→Upregulation of selections causing rolling of lymphocytes →→→Upregulation of VCAM and ICAM causes binding of neutrophils, etc. →Secretion of chemokines (also induces chemokine production in macrophages) →→→Enhances the affinity of leukocyte integrins for their ligands →→→Induce leukocyte chemotaxis and recruitment →Production of factors that promote clot formation ∙Acts on mononuclear phagocytes to induce IL-1 production ∙Acts on hypothalamus to induce fever →Mediated by prostaglandins ∙Acts on hepatocytes to induce acute phase reactants ∙Prolonged production leads to wasting of fat and muscle (cachexia) →Ex: wasting w/ terminal cancer patient, longstanding HIV infection →Appetite suppression →Reduced synthesis of lipoprotein lipase ∙Biologic effects of large amounts →Myocardial contractility and vascular smooth muscle tone are inhibited, leads to marked fall in BP (shock) →Intravascular thrombosis →Severe metabolic disturbances (i.e. fall in blood glucose levels) ∙Role in sepsis Therapeutic modulation ∙There are a number of biologics available that block TNF- α binding to TNF receptors ∙Used to treat inflammatory and/or autoimmune disorders

Clinical interventions to wound healing

Problems ∙Incomplete wound closure ∙Excessive scar formation (non-functional tissue) ∙Diabetics Approaches ∙Using tripartite interdependence: cells, matrix, cytokines ∙Deliver GFs: single or multiple delivery, timed release ∙Insert scaffolding - using different natural and synthetic materials ∙Combinations - GFs and matrix ∙Deliver cells: mesenchymal stromal cells (MSC) →Multipotent lineage potential →Cultured to begin specific tissue lineage →Harvested from BM, lipid tissue

Screening test for identification of C. albicans

Production of germ tubes by C. albicans in serum or plasma after 2-3 hours incubation at 37°C

Virus-Host Interactions: Productive infection

Progeny virus is produced Infected cells are permissive for the virus Types of productive infection ∙Lytic infection →Destruction of the host cell →Produces a cytopathic effect (CPE) →Types of CPE →→→Syncytia formation (multinucleated giant cells) →→→Cell rounding or vacuolization →→→Inclusion bodies →→→→→New material within a host cell detected by histological stains →→→→→Sites of viral replication →*Naked virions produce lytic infections* ∙Persistent (chronic) infection →Continual shedding of virus →→→No destruction of the host cell at the cellular level (budding) →→→Only a few cells at the tissue level population are infected, but enough other cells that are uninfected in the tissue to keep that tissue alive and viable

Type 1 pathogens (viruses and intracellular bacteria) induce a TH1 immune response mediated by CD4 cells, and a CD8 effector T cell response

Proinflammatory response is trying to clear infection If it doesn't clear infection, you get significant damage

Regeneration

Proliferation of cells replaces lost tissue Reconstructs normal architecture 3 aspects considers: ∙cell types ∙tissue architecture ∙amount of tissue loss

GI function & prostaglandins

Promote the secretion of mucous Inhibit the secretion of acid

Naked, icosahedral viruses

Properties ∙Can dry out and retain infectivity ∙Can survive the acidic conditions of the GI tract ∙Are resistant to temperature extremes, detergents and poor sewage treatment ∙Released by cell lysis →Do not need an envelope so they have no need for the lipid bilayer remaining intact Clinical properties ∙Survival in the environment enables transmission via fomites (mechanisms of indirect of transmission like doorknobs, computers; objects that can become contaminated by a sick person and infect others) ∙Survival in the GI tract enables transmission via the fecal-oral route →Shed in stool →Present in sewage-contaminated water →Responsible for most cases of viral gastroenteritis →More difficult to disinfect contaminated surfaces ∙Cytopathic →Harm the cell they infect

Enveloped viruses

Properties ∙Must stay wet to retain infectivity ∙Acid and heat labile ∙Infectivity is destroyed by organic solvents and detergents ∙Released by budding with or without cell lysis Clinical properties ∙Transmitted through droplets and secretions (not transmitted via fomites) →Respiratory route, blood, organ transplants ∙Cannot survive in the GI tract for the most part, not spread fecal-orally ∙Need not kill infected cells to spread →Can persist for a little longer than naked viruses in a host

Type 1 Interferons

Properties of IFN polypeptide ∙About 20 different IFNα genes →IFNα polypeptides are about 18kDA ∙Only one IFNβ gene →IFNβ polypeptide is about 20kDA Cell source ∙IFNα-predominantly mononuclear phagocytes ∙IFNβ-probably multiple Cell targets: virtually all Receptor: all IFNs seem to interact w/ same receptor Stimulators of IFN production ∙Viruses are most potent stimulator of IFN production (dsRNA) ∙Activated T cells can also stimulate IFN production in mononuclear phagocytes Signal transduction ∙Activate receptor associated JAK/STAT protein kinase pathway ∙Kinases phosphorylate a specific transcriptional factor which moves from the cytoplasm to the nucleus ∙Transcriptional factor binds to interferon sequence response elements (ISRE) in promoter regions of interferon inducible genes Response to IFNs ∙Oligoadenylate synthetase ∙dsRNA-activated serine/threonine kinase (PKR16) →Blocks viral transcription and translation ∙RNAses

Renal Function & Prostaglandins

Prostaglandins promote: ∙Increase renal blood flow ∙Increase GFR ∙Cause renal vasodilation ∙Increase the excretion of Na⁺, K⁺, H₂O

Functions of viral capsids

Protect the genome from degradation Involved in entry and uncoating ∙Naked viruses have binding proteins in the capsid Involved in assembly ∙Package viral enzymes if necessary

Viral receptors

Proteins or carbs on glycoproteins or glycolipids on the cell surface of the host cell Physiological role in the host cell (not just for viruses to bind to them) Type of receptors ∙Molecules involved in cell-cell interactions ∙Hormone, cytokine, or complement receptors ∙Enzymes

Properties of antigens

Proteins or chemicals bound to proteins Chronic exposure Do not stimulate the innate immune system

Aspirin (acetylsalicylic acid)

Pure salicylic acid is incredibly rough on the GI tract, so it is generally not used (except topically, b/c it does not go to GI tract) ∙Aspercreme is example of topical agent Acetylation of salicylic acid → significantly decreased GI effects ∙Once absorbed, hydrolyzed to salicyclic acid *Actions: ALL 4 A's* ∙Analgesic, anti-inflammatory, antipyretic, antiplatelet *Stimulates respiration* ∙Uncouples oxidative phosphorylation ∙Stimulates the medullary respiratory center *Alters acid-base equilibrium*

Adjuvants

Purified protein vaccines induce poor immunity ∙Improved by adjuvants →substances that induce non-specific inflammation →Adjuvants also cause soluble antigens to aggregate →→→Clear slower →→→Increase phagocytosis

Rocky Mountain Spotted Fever

RMSF is a potentially lethal, tick-borne disease caused by gram (-) obligate intracellular Rickettsia rickettsii w/ tropism for endothelial cells Most common fatal tick-borne disease in US and presents as febrile vasculitis Characterized by centripetal rash, which begins on wrists, ankles and forearms and then spreads to involve trunk Nationally notifiable disease Incidence highest among children and fatality rates highest in individuals older than 40 and in males

Hyperacute graft rejection

Rapid vascular occlusion Begins within minutes after host blood vessels are anastomosed to the graft vessels) ∙Even before patient leaves the OR Intravascular clotting and thrombosis ∙Kidney becomes rapidly cyanotic, mottled, flaccid ∙Secretes a few drops of bloody urine Usually recipient has had multiple transfusions or pregnancies (worse w/ multiple fathers involve), prior grafts ∙Basically looking at person who is immunized to MHC Not reversible Mechanism of pathology: mediated by *pre-existing antibodies to vascular endothelium that activate complement* ∙Deposited on the vessel wall ∙Endothelial injury and fibrin-platelet thrombi ∙Followed by neutrophil accumulation ∙Necrosis MHC Class I: normally expressed on endothelium ∙Class II: induced on endothelium as a result of inflammation, infection, trauma ∙Blood group antigens (ABO) *Type II hypersensitivity reaction that looks like a Type III* b/c of vasculitis ∙This is antibody specific for MHC binding to vascular endothelium in a specific way ∙So what is happening here is that antibody is binding specifically to vascular endothelium, but downstream pathology is reminiscent of that which is caused by immune complexes (i.e. vasculitis) ∙Type II b/c it is Ab binding cell surface, but mimics vasculitis seen w/ immune complexes

Ras in T cell activation

Ras molecules represent a family of 21kDa proteins with intrinsic GTPase function Ras is activated when the bound GDP is replaced by GTP Ras is inactivated when GTP is hydrolyzed to GDP

Surveillance criteria for ECM of LD

Rash must exceed >5cm in diameter It should show expansion (peripheral migration of organisms) Should be > 1 week Previous infection is NOT necessarily protective against future infections

Anthrax Vaccine

Recommended in 18-65 years of age and is administered at 0, 2, 4, 6, 12 and 18 weeks by subcutaneous route followed by annual boosters PEP - vaccine can be used on day 0, two and four weeks as an investigational approach along w/ 60 or 100 day course of antibiotics

Three mechanisms from macrophage accumulation and persistence in chronic inflammation

Recruitment (via chemotactic factors) Division Cytokines that are made by other macrophages (sometimes other cell types) in extracellular area that allow for immobilization effect ∙Macrophages are being chemically induced to stay in this area

Other common properties of allergens

Relatively small Highly soluble Often carried on dessicated particle ∙Easily eluted at a mucous membrane ∙Diffuses across membrane

Systemic fungal pathogens

Remember the top 3 (endemic to US)

Treatment & Prevention of Candidiasis

Remove infected catheters & implants if possible Systemic therapy: ∙Fluconazole, amphotericin B & echinocandins ∙Fluconazole prophylaxis helpful in some high-risk patients ∙Resistance is becoming a problem with C. krusei & C. glabrata (some isolates of C. albicans) →Fluconazole resistant Candida are susceptible to *posaconazole* Avoid broad-spectrum antibiotic use

Peptostreptococcus

Representative organism of gram (+) cocci Colonize oral cavity, GI tract, genitourinary tract and skin Cause disease when spread to sterile sites Sinusitis, pleuropulmonary/intraabdominal infections, pelvic abscesses, salpingitis (fallopian tubes), cellulitis, bone/organ infections Infections are polymicrobial

Healing by second intention (wounds w/ separation edges)

Represents a large tissue defect that must be filled - as parenchymal cells cannot completely fill, abundant granulation tissue grows in from margins Differences between this and first intention healing: ∙Inflammatory reaction more intense - more necrotic debris and exudates to be removed ∙Larger amounts of granulation tissue formed ∙Wound contraction - occurs in lg surface wounds - presence of myofibroblasts *Note: Primary or secondary intention wound healing is determined by the nature of the wound, not by the healing process itself*

Resistance to host immune response and/or non-immune response clearance mechanisms

Resistance to lysozyme and basic proteins (eg, defensins) ∙Defensins are basically antimicrobial proteins ∙Insert into membranes of microbial cells, damage membrane and lead to them rupturing over time Resistance to endocytosis and phagocytosis (eg, capsule) ∙Capsule prevents immune cells from recognizing them Resistance to intracellular destruction - prohibition of lysosomal killing ∙Binding of lysosomes prohibited, same with phagosomes

Sequelae following tissue damage/loss

Resolution Regeneration Repair NOTE: ALL of these processes could occur in the same tissue, and begin as soon as there is significant tissue damage ∙Wound healing is a continuum b/w pathologic states of repair and ineffective healing and does not wait for inflammation to subside

Clinical Disease of Non-Spore Forming Gram (-) Bacteria

Respiratory infections ∙50% of chronic sinus & ear infections, and all periodontal infections involve mixtures of Gram (-) anaerobes (non-fragilis bacteriodes usually isolated) ∙lower tract infection associated w/ history of aspiration (not common) Brain abscess ∙Associated w/ history of chronic URT infections ∙Polymicrobial ∙Prevotella, Porphyromonas, Fusobacterium, Peptostreptococcus, and other anaerobic and aerobic cocci Intra-abdominal infections ∙Anaerobes virtually isolated w/ all these infections (anaerobes predominate in gut) ∙B. fragilis is the most common ∙Other strains of Bacteroides, other anaerobes, and aerobic gram (+) cocci Gynecological infections ∙Mixture of bacteria isolated from infections ∙PID, abscesses, endometritis, surgical wound infections ∙B. fragilis responsible for abscesses ∙Prevotella bivia and PRevotella disiens important isolates Skin and soft-tissue infections ∙Bacteria introduced by trauma ∙Spectrum of illness: no disease or progression to myonecrosis ∙B. fragilis associated w/ serious disease Bacteremia ∙Cause 3-5% of infections ∙B. fragilis most commonly isolated from blood cultures Gastroenteritis ∙Enterotoxin-producing B. fragilis cause a self-limiting watery diarrhea ∙Incidence highest in children < 5yo

C. perfringens: Group A

Responsible for most human infections Produces Alpha-toxin & Enterotoxin Enterotoxin ∙Heat labile protein that binds to epithelial cells in the small intestine ∙Disrupts ion transport → fluid loss → watery diarrhea

Pathogenesis of RMSF

Rickettsia are directly cytopathic, they increase vascular permeability leading to edema, hypovolemia, hypotension, and hypoalbuminemia Cell necrosis and occlusion of vascular lumen lead to diffuse microinfarction

Examples of Obligate Intracellular Bacteria Family Rickettsiaceae

Rickettsia rickettsii - Rocky Mountain spotted fever ∙Vector is hard tick (wood and dog ticks) ∙Most common rickettsial pathogen in US ∙Virulence: intracellular growth in cell cytoplasm, protects from immune clearance, replicates in endothelial cells giving vasculitis, hypovolemia and hypoproteinemia by loss of plasma in the tissues, results in reduced perfusion of organs and organ failure Rickettsia prowazekii - causes louse-borne typhus ∙Vector is human body louse ∙Virulence: intracellular parasite, replicates in endothelia, causes vasculitis Rickettsia tsutsugamushi - causes scrub typhus ∙disease transmitted to humans by mites (chiggers, red mites) ∙Virulence: intracellular parasite, replicates in endothelia Coxiella burnetii - Acute & chronic Q fever ∙Inhalation - airborne particles from livestock, cats, dogs ∙Virulence: intracellular replication, resists lysosomal degradation & formation of immune complexes in chronic disease ∙Symptoms: acute-20d incubation, sudden onset of headache, chills, mild respiratory symptoms, 50% have hepatosplenomegaly --- →*Chronic - months to yrs incubation - subacute endocarditis, insidious with poor prognosis* ∙Even though it is in a Rickettsia family, it has a different mechanism for evading host →Resists lysosomal processing events/enzymes Ehrlichia chaffeensis - causes human monocytic ehrlichiosis ∙Lone Star tick is primary reservoir-vector for transmission ∙Virulence factors: intracellular replication with ability to sequester or destroy infected circulating cells ∙Symptoms: like those of Rocky Mountain spotted fever →Worse b/c of loss of WBCs ∙~12 d after tick bite - a high fever, headache, malaise, myalgia, also a leucopenia caused by leukocyte destruction and thrombocytopenia are observed

Aspirin overdose

Salicylism

Use of ibuprofen

Same as aspirin

Use of naproxen

Same as aspirin

Nystatin

Same mechanism of action as amphotericin B Not absorbed so it is not present in tissues Not used for systemic infections Used for cutaneous or mucocutaneous candidiasis ∙Oropharyngeal or vaginal Can cause vomiting, nausea & diarrhea

General properties for cytokines

Secretion is a brief, self-limited event → do not want this happening willy-nilly Pleiotropism ∙Each cytokine may mediate diverse effects Redundancy ∙Multiple cytokines may have the same function (OVERLAP IN ACTIVITY) Cytokines influence the secretion and activity of other cytokines ∙Effects may be additive, synergistic, antagonistic Cytokine action may be local or systemic ∙Autocrine, paracrine, and endocrine effects Cytokines act on specific cell surface receptors ∙Receptor expression is regulated by external signals The cellular response to cytokines involves changes in gene expression Involved in both innate and adaptive immune responses Results in acquisition of new function or proliferation

Electron Microscopy: Establishment of C pneumoniae acute infection

See organisms sitting inside cell Acute infections - happen quickly, and haven't started dividing in 24 hr time frame ∙Can live inside monocytes for significant amounts of time ∙An organism that has invaded of monocyte can take over cell for weeks →Monocyte typically have lifespan of 1 day otherwise

Selective COX2 inhibitors

Selective inhibition of COX2, no inhibition of COX1 at normal therapeutic concentrations Celecoxib (Celebrex) Rofecoxib (Vioox) - found increased risk of MI and stroke so pulled off marker

Macrophage-Lymphocyte interactions in chronic inflammation

Shows interaction of activated lymphocytes w/ activated macrophages Lymphocytes want to upregulate express of lymphocytes, so release IL-2 Also want to activate macrophages, so release IFN-gamma

Tissue architecture

Simple structures regenerate better than complex ones Clinical consequences of imperfect regeneration ∙Chronic inflammation of liver results in much hepatocyte proliferation, but w/ damage to the connective tissue ∙Regenerated tissue produces an abnormal nodular architecture - cirrhosis →This may the result in hemodynamic abnormalities in the hepatic portal venous system giving portal HTN, hemorrhage, death

Protozoa

Single-celled organisms w/ the ability to multiply w/in their host They may excyst (cyst → trophozoite) and encyst (trophozoite → cyst) ∙Cysts is the infective stage ∙Trophozoites are metabolically active forms causing harm to host (hit and run)

Normal stratified epithelium

Skin is composed of layers of keratinocytes Layers ∙Basal layer (proliferating cells) ∙Granular layers (differentiating cells) ∙Stratum corneum (flattened cell remnants - empty) →Form HMW polymers of cornified proteins A wound disrupts this organization

Propionibacterium

Small gram (+) rods Found on skin, oropharynx, conjunctiva, female genital tract Anaerobic or aerotolerant Propionibacterium acnes on skin ∙Contributes to acne (inflammatory response) ∙Opportunistic infections in patients w/ prosthetic devices or intravascular lines

Description of viruses

Small, obligate intracellular pathogens ∙Filterable agent that is not visible by light microscopy ∙No subcellular organelles ∙Replicate only in living cells →Cannot be cultured like bacteria and rely on the host cell protein synthesis machinery to survive →Can culture them by placing them on top of a layer of cells ∙Progeny virions are assembled (the virus does not divide like bacteria)

Candida as an opportunistic infection

Species responsible for ~95% of blood stream infections due to Candida: ∙C. albicans, C. glabrata, C. parapsilosis, C. tropicalis Most common cause of fungal infections in immunocompromised individuals 4th most common blood culture isolate in hospitals Anti-fungal resistance is a growing concern with opportunistic/nosocomial Candida spp. ∙Especially C. glabrata & C. krusei Candida species associated with blood stream infections in table

Diagnosis of Candidiasis

Specimens: ∙Tissue biopsies, sputum, CSF, blood, urine Yeast & hyphal forms of organism Positive culture from normally sterile site is significant ∙Blood cultures are positive in only ~40-60% of cases of candidemia ∙Selective chromogenic medium differentiate species by color & morphology Circulating candidal antigens are indicative of systemic infection ∙Antibody titers aren't diagnostic Germ tube test is used to identify C. albicans Commercial test now available that looks for β-d-glucan ∙Fungitell assay - modified Limulus lysate assay ∙Highly sensitive, rapid diagnostic test that detects (1→3)-β-D-glucan in serum

Treatment for Toxoplasmosis

Spiramycin (for acute intra-partum infection) ∙3g/day and its dispensing requires approval from FDA ∙can be obtained at no cost through FDA Atovaquone Dapsone + pyrimethamine (Daraprim) + folinic acid (Leucovorin) ∙Pyrimethamine is potentially teratogenic, producing reversible dose-related bone marrow depression SDZ (sulfadiazine) Clindamycin (cleocin) Co-trimoxazole (TMP-SMZ) ∙Trimethoprim is avoided in 1st trimester b/c it is folid acid antagnoist Consider brain biopsy if no response in 14 days

Hygiene Hypothesis

States that exposure to microorganisms (decreased hygiene) during early age is important for development of a balanced immune system Increased hygiene leads to an uncontrolled Th2 response to allergens, leading to atopic diseases

IFN-γ

Stimulates B cell differentiation (class switching to IgG2) Inhibits Th2 cell growth Activates macrophages Increases Class I and Class II MHC expression on macrophages and other cells Activates NK cells Antiviral

Rat Bite Fever

Streptobacillus moniliformis and Spirillum minus are causative organisms Characterized by fever of abrupt onset, chills, rash, arthritis, and HA Incubation period up to 3 wks Rx: IV penicillin G for 7-10 days followed by oral penicillin for 7 days ∙Doxy can be used too

Viruses are categories based on subfamilies

Subfamilies: alpha, beta, gamma Criteria are used to sort these subfamilies: ∙Organization of the genome ∙Tissue tropism and site of latency ∙Pathogenesis and disease manifestation Most viruses are referred to by their common name (except 6 and 7 which don't have common names

Products released by macrophages

Such a variety of factors that these cells can be thought of as cells that come in and clean up area, so they make molecules to clean up garbage, and molecules that stimulate laying down of new material ∙Sometimes make molecules that call in other cell types (i.e. fibroblasts) to stimulate healing process

Waterborne Outbreak

Suggested by the sudden and widespread gastroenteritis affecting persons of all ages In many ways, the clinical lab is the first line of defense in providing a warning than an infectious disease is threatening the community Home Water Filter - 800 - NSF - 8010 ∙Tested and certified by NSF standard 53 for cyst reduction and cyst removal ∙Reverse osmosis treated ∙Absolute micron size of one or smaller Bottled Water Label Information ∙Reverse osmosis treated ∙Distilled ∙Filtered through an absolute one-micron or smaller filter

Process of wound healing

Summary of processes: 1. induction of inflammation by injury 2. regeneration of parenchymal cells 3. migration & proliferation of parenchymal cells + connective tissue cells 4. synthesis of ECM 5. remodeling 6. collagenization and increased wound strength

IL-4

Suppress Th1 cells Cellular sources ∙CD4+ Th2 cells ∙Mast cells? ∙Targets and biologic activities →*B cells: Ig class switching to IgE* →→→makes for hypersensitivity rxns (allergies) →Th2 cells: proliferation, differentiation →Macrophages: inhibition of IFN-γ mediated activation →→→Due to Th1 suppression

Treatment, Prevention and Control of Actinomyces

Surgical debridement of tissue along w/ prolonged treatment w/ penicillin Good oral hygiene and antibiotic prophylaxis can lower risk of infection

Treatment of Non-Spore Forming Gram (-) Bacteria

Surgical intervention and antibiotic therapy needed for serious infections *B. fragilis, Prevotella, Porphyromonas, and some Fusobacterium produce B-lactamases* Infections endogenous, so difficult to control Use control and prophylactic treatment to prevent spread to sterile sites

Candidiasis

Systemic/invasive infection Cutaneous & mucocutaneous infections ∙Thrush ∙Vaginal yeast infections

Lymphocyte recirculation: Overview

T cells bind to endothelial cells in thin walled high endothelial venules (HEV) Squeeze through vessel wall Enter cortical region of lymph node Pass through tissue, examine APC ∙See antigen: activate, proliferate, differentiate ∙Don't see antigen: recirculate out The overall process is shown schematically in image

How CD8+ T cells recognize antigen

TCR engages MHC Class I: peptide complex ∙Peptides are usually derived from microbial sources w/in the antigen-presenting cell ∙*Typically viral* Class I MHC (like Class II) may also present peptides derived from microbes that have been phagocytized by dendritic cells ∙If they are transported from the phagosomes and into the cytosol ∙Called cross-priming or cross-presentation CD8 interacts w/ an invariant region of MHC Class I

Toxoplasma encephalitis (TE)

TE is an AIDS indicator illness present when the CD4 count drops <100/mm^3 Most common cause of focal necrotizing encephalitis, and second most common cause of necrotizing retinitis (after CMV in AIDS) Presence of many brain abscesses (Swiss cheese pattern) is the most characteristic feature of TE Other features include mental status changes, seizures, focal motor deficits, cranial nerve disturbances, sensory abnormalities, cerebellar signs, movement disorders and neuropschiatric findings The most typical focal neurological findings are hemiparesis and speech abnormalities Other symptoms include prolonged febrile illness w/ cough and dyspnea, clouding of consciousness, headache, lethargy, etc.

Rx for RMSF

Tetracycline and chloramphenicol Doxycycline (in adults) is given as 100 mg BID for 3D after fever subsides

Host response to extracellular bacteria

The 'big ways' that extracellular bacteria cause disease ∙Invasiveness ∙Inflammatory response ∙Secretion of exotoxins →Exotoxin A (Pseudomonas aeruginosa) →Lethal factor (Bacillus anthracis) ∙Gram (-) bacteria also make endotoxins →Potent stimulator of TNF-α How the immune response fights extracellular bacteria ∙Clearance of organisms ∙Neutralization of toxins Natural immunity to extracellular bacteria: THE PRINCIPAL MECHANISMS OF INNATE IMMUNITY TO EXTRACELLULAR BACTERIA ARE: ∙*Complement activation* →Activation of *alternate complement cascade* →Direct activation by peptidoglycan (Gram +) or LPS (Gram -) →→→Generation of C3b:opsonization and enhanced phagocytosis →→→Generation of the membrane attack complex: bacterial lysis →→→→→Can occur via the classical or alternative pathway →Mannose pathway initiated by bacterial expression of mannose →Complement byproducts (C3a and C5a) participate in inflammation by recruiting and activating leukocytes ∙*Phagocytosis*/stimulation of microbiocidal activity →Phagocytes recognize extracellular bacteria via surface receptors →→→Mannose receptors →→→Scavenger receptors →Phagocytes use Fc receptors and complement receptors to recognize opsonized bacteria →TLRs contribute to activation of phagocytes ∙*Inflammation* ∙Production of *cytokines* in response to extracellular bacteria →Activated phagocytes secrete cytokines →Pro-inflammatory cytokines: →→→IL-1 →→→TNF →→→IL-6 →→→Chemokines →Cytokine effects in infection by extracellular bacteria →→→Stimulate inflammation →→→Induce adhesion of neutrophils and monocytes to vascular endothelium →→→Induce migration, local accumulation and activation of inflammatory cells →→→→→Eliminate bacteria, but induce normal tissue injury →→→*Fever* →→→Stimulation of acute phase reactants →→→Regulate specific immunity through effects on B lymphocytes, T lymphocytes, APC →Bad things cytokines can do: *Septic shock* →→→Severe, often fatal, pathologic consequence of disseminated infection by gram (-) and some gram (+) bacteria →→→Sepsis (early phases) is caused by cytokines →→→→→TNF-α, IL-1 and IL-6 are the principal mediators (cytokine storm) →→→→→IL-12 and IFN-γ may contribute →*Virchow's classic triad in sepsis* →→→Changes in coagulation - disseminated intravascular coagulation →→→Endothelial cell injury →→→Abnormal blood flow →→→All three are present in sepsis and culminate in: →→→→→Reduced blood flow to vital organs = end organ failure →→→→→Shock →→→→→Death

The VEGF ligand has additional effects in the tumor environment

The VEGF ligand may have other effects on tumor growth beyond promotion of angiogenesis, including the prevention of immune response ∙Tumors have developed a variety of mechanisms to avoid immune responses ∙One of these mechanisms involves the inhibition of dendritic cells, which are antigen-presenting cells that stimulate B cells and T cells ∙Recently, it has been demonstrated in vitro that VEGF can prevent the functional maturation of dendritic cells from their hematopoietic progenitors ∙Tumor secretion of VEGF may play an important role in suppressing the immune antitumoral response Additionally, the effects of tumoral expression of VEGF are currently being investigated in dendritic cells and hematopoietic stem cells

The VEGF ligand: at the center of the angiogenic pathway

The VEGF ligand: ∙Stimulates vascular endothelial cell growth, survival (anti-apoptotic effect) and proliferation ∙A genetically stable protein ∙Continuously expressed through entire tumor life cycle ∙Direct and continuous VEGF inhibition is an important antitumor strategy

The VEGF Pathway

The VEGF pathway begins with induction of VEGF production through environmental and cellular triggers and continues with multiple interactions between the various members of the VEGF family of ligands and corresponding VEGF transmembrane receptors (VEGFRs) ∙These interactions lead to multiple downstream effects, including tumor angiogenesis

Turning on the angiogenic switch

The angiogenic switch is the moment at which a tumor begins to over-express pro-angiogenic factors such as VEGF ∙The switch overwhelms the delicate balance of pro- and anti-angiogenic factors to grow new vasculature, thereby facilitating the growth of the tumor Angiogenesis is tightly regulated by a number of pro- and anti-angiogenic molecules ∙Under normal conditions, there is a delicate balance between pro- and anti-angiogenic factors, and angiogenesis does not occur ∙However, during tumor growth, a variety of environmental and cellular triggers lead to over-expression of pro-angiogenic factors ∙These factors, including vascular endothelial growth factor (VEGF), can tip the balance toward angiogenesis

Etiology of RMSF

The family Richettsiaceae includes genus Ricketssia, Ehrlichia, Coxiella, and Bartonella The organisms are fastidious pleomorphic obligate intracellular bacteria that multiply in the cytoplasm of infected cells They are small, gram (-) coccobaccilli, which are maintained in an arthropod-animal cycle Infection of endothelial lining of arterioles, capillaries and venules leads to dermatoses and hematologic alterations

Several proteins are expressed de novo at cell surface during T cell activation

The high affinity IL-2R ∙IL-2 = important T cell growth factor ∙Second image: When IL-2 binds to the high affinity receptor Activation Marker: CD40L ∙One of the most important surface proteins involved in CD4+ effector (Th1 and TH2) function ∙CD40 (receptor for CD40L) is expressed on macrophages, dendritic cells and B cells ∙Binding of CD40L to CD40 activates the cell bearing CD40 →B cells: promotes proliferation, antibody secretion and class switching →Macrophages: activation, killing of phagocytosed microbes

Natural immunity to intracellular bacteria

The innate immune response to intracellular bacteria is mediated mainly by phagocytes and NK cells ∙Initially, phagocytic cells (neutrophils and macrophages) ingest and attempt to destroy these pathogens →Intracellular microbes resistant to degradation w/in phagocytes →But may activate them by binding TLRs and other receptors Key player: NK cells ∙Intracellular infection induces NK cells by: →Activating ligands for NK cells on the infected cell surface →IL-12 and IL15 from dendritic cells and macrophages ∙NK cells then produce IFN-γ, which acts on macrophages →Activation →Killing of phagocytosed bacteria Adaptive immunity to intracellular bacteria: THE MAJOR PROTECTIVE IMMUNE RESPONSE AGAINST INTRACELLULAR BACTERIA IS T CELL-MEDIATED IMMUNITY ∙People w/ AIDS are extremely susceptible to infection by intracellular bacteria ∙NK cells and cytokines only transiently control infection ∙T cell activation of macrophages very important →Mediated by CD4+ Th1, under influence of IL-12 →Th1 cells activate macrophages to kill phagocytized bacteria through: →→→IFN-γ →→→CD40L →Macrophages then produce microbicidal products →→→ROS →→→NO →→→Lysosomal enzymes ∙CTL →Phagocytized bacteria 'leak' into cytosol →OR bacteria escape from phagosomes and enter cytosol →Cytosolic organisms no longer accessibly to microbicidal activity of phagocytes, so killing is accomplished by CT Tissue injury caused by intracellular bacteria ∙Due to macrophage activation ∙b/c intracellular bacteria have evolved to resist killing w/in phagocytes →Often persist for longer periods →Cause chronic antigenic stimulation →Prolonged T cell and macrophage activation ∙Formation of granulomas ∙Granulomatous inflammation hallmark of infection by intracellular bacteria

Relative size of various viruses

The largest viruses can be the size of intracellular bacteria (like Chlamydia)

The VEGF ligand: Multiple effects leading to tumor neovascularization

The mechanisms from which the various functions of the VEGF ligand arise in endothelial cells are shown here These functions include proliferation, permeability, invasion, migration, survival, and activation

More detailed look at lymphocyte recirculation

The passage of a naïve T cell out of the bloodstream (or from the lymphatics) and through the HEV to the cortex of a lymph node is controlled by contacts made by cell surface interactions b/w surface molecules on the T cells and those on the endothelium These and other cell-to-cell contacts are initiated by cellular adhesion molecules ∙There are 4 structural classes of adhesion molecules that are important in lymphocyte recirculation and other processes of immune system →Selectin →Vascular addressions (mucin-like): CD34 →Integrins: LFA-1 →Members of the immunoglobulin superfamily: LFA-2 (CD2), ICAM-1, ICAM-2 Two important interactions in initial contact of the T cell with the endothelial cell ∙L-selectin (T cell) w/ CD34 (endothelium) ∙L-selectin (T cell) w/ GlyCAM-1 (endothelium) ∙Process also influenced by chemokines (CCL21 binds to CCR7 chemokine receptor) Later, the contact b/w the naïve T cell and the endothelium is strengthened by the interactions of: ∙LFA-1 (integrin) w/ ICAM-1 and ICAM-2 (members of the Ig superfamily) Homing of T cells into draining lymph nodes significantly enhanced at sites of acute inflammation ∙Egree via efferent lymphatics transiently reduced ∙Probably due to cytokines produced as part of the innate immune response (IFNs)

Physiologic appearance of angiogenic switch

These images depict neovascularization in a rat tumor model over 12 days following implantation of a tumor ∙By Day 12, neovascularization is apparent, with angiogenic areas easily visible ∙Thus, it is possible to visualize the effect on the tumor environment when the "angiogenic switch" is turned on

How do CD4+ Th1 effector T cells activate macrophages

They send two signals IFN-γ ∙Primary signal ∙Made by Th1 (but also NK cells and possibly, macrophages) CD40L ∙Secondary signal ∙Makes the cells responsive to IFN-γ

VEGF induces abnormal vasculature

This image depicts normal vs tumor cell vasculature ∙A: simplified sketches ∙B: photographs of vasculature ∙C: computerized renderings ∙D shows the balance of pro- and anti-angiogenic factors in normal and abnormal vasculature →Note that under normal conditions, the vasculature is well organized, and the balance of pro- and anti-angiogenic factors is maintained →By contrast, tumor vasculature is tortuous and hyperpermeable, and the balance of pro- and anti-angiogenic factors favors neovascularization The VEGF ligand stimulates vascular permeability in small blood vessels. ∙The increased permeability causes the leakage of plasma proteins and the formation of an extravascular fibrin gel, providing a suitable environment for endothelial cell growth ∙In tumors, high levels of VEGF result in vasculature that is excessively permeable and leaky, thus leading to increased interstitial pressure within the tumor and uneven delivery of nutrients, oxygen, and therapeutic agents to the tumor

T cell activation

This is the term that we use for the process that occurs when a naïve T cell encounters its specific antigen and is stimulated to differentiate into an effector T cell (also called priming) ∙First step in any adaptive immune response Once infection begins, the system must bring the minute fraction of specific helper T cells (~1:1 million) into contact w/ the pathogen ∙How does this happen? ∙It's important to remember that we do not initiate adaptive immune responses at the site of infection, *we initiate helper T cells in the secondary lymph tissue* →For antigens in the skin and other peripheral tissues - regional lymph nodes →For blood borne antigens - spleen →For antigens in the respiratory mucosa - tonsils and bronchial-associated lymphoid tissue →For antigens in the GI system - Peyer's patches, GALT and appendix

VEGF stimulates vessel growth, proliferation and survival

This slide shows the many effects of the VEGF family of ligands and their receptors in tumor angiogenesis ∙VEGF ligand stimulation of VEGFR-1 and VEGFR-2 on endothelial cells induces endothelial cell proliferation, migration, and survival, as well as vascular permeability—all effects that lead to tumor angiogenesis ∙VEGF may also recruit endothelial progenitor cells and VEGFR-1-expressing myeloid cells to sites of tumor neovascularization ∙Finally, VEGF-C and VEGF-D interact with VEGFR-3 on the surface of lymphatic endothelial cells, leading to lymphangiogenesis The VEGF ligand promotes tumor growth by stimulating tumor angiogenesis ∙The binding of the VEGF ligand to receptors on endothelial cells initiates the creation of a vascular network, allowing tumors access to the oxygen and nutrients they need to grow and metastasize The VEGF ligand also acts to promote the survival of existing tumor vasculature ∙Endothelial cells need VEGF for their continued survival in immature blood vessels. In the absence of growth signals, endothelial cells undergo programmed cell death (apoptosis) ∙Upon pericyte association with vascular endothelial cells (vascular maturation), the VEGF ligand is no longer required for survival

Entry/Penetration

Through the plasma membrane ∙Viral-cell fusion (enveloped viruses) ∙Hydrophobic interactions create a channel through the membrane (naked viruses have hydrophobic areas on their capsid and create the path into the cell) Receptor-mediated endocytosis ∙Most common route of entry ∙Used by both enveloped and naked viruses Types of receptor-mediated endocytosis ∙Clathrin-mediated entry (pH dependent entry) →Most common (best studied, used the most) →Clathrin coated pits →Pits become endosomes (become acidified) →→→Some viruses require the exposure to the acidic endosome to become active →→→Some need to be fused with lysozomes so that the virus can be activated by the proteasomes within ∙Caveolae-dependent (non-pH dependent pathway) →Membrane invaginations called caveolae →Contain a lipid raft-associated protein called caveolin →Caveosomes (neutral pH) →→→Viruses that do not need an acidic environment can enter this way ∙Clathrin and caveolin independent →Entry via clathrin coated pit (1) and caveolin-dependent and clathrin-and-caveolin independent (2) ∙Entry of naked, icosahedral viruses →Through plasma membrane hydrophobic channels or via receptor-mediated endocytosis →Conformational change in capsid proteins →Virus forms a pore through the membrane →Virus lyses the membrane of the endosome

Hunter strategy

Tick attacks host

Epidemiology of RMSF

Tick is both the vector and main reservoir of R. rickettsii ∙Dermancentor variabilis (dog tick) in eastern US ∙Dermacentor andersoni (wood tick) in Rocky Mountain States ∙Amblyomma americanum (Lone Star Tick) in southwest Ticks live up to 5 years, are resistnant to diesiccation, cold, starvation and have high reproductive potential

Ticks

Ticks are currently considered to be second only to mosquitoes as vectors of human infectious diseases Highly specialized group of obligate, bloodsucking, nonpermanent ectoparasitic arthropods that feed on mammals, birds and reptiles Example of tick borne disease: Lyme disease

Ambush strategy

Ticks climb up vegetation and wait for passing host

Engorgement

Ticks may increase their body weight up to 120x Ticks feed only once in each development stage and blood is their only food b/c engorged ticks may rarely grow to reach 2cm, patients have consulted dermatologists concerted that they have a wart, melanoma, or other skin tumor

Toxoid vaccines

Toxin activity is destroyed (formalin) Retains sufficient antigenic activity to protect against disease ∙Tetanus ∙diptheria

Production of toxic or deleterious molecules

Toxins - endotoxins (LPS) and exotoxins Fermentation end products that are toxic and O2 consumption ∙i.e. gas gangrene - C. perfringens

Toxoplasmosis

Toxoplasma gondii = obligate intracellular parasite creating a sea of toxoplasma infection around us ∙Toxon = arc ∙Plasm = form (crescent shaped parasite) ∙Felids are definitive host A cosmopolitan AIDS defining parasite ∙Continuum of manifestations in persons of varying degrees of immune competence as follows: congenital, infection in immune competent-host, ocular infection and infection in immune-compromised host ∙*Congenital* - incidence is highest when maternal infection is acquired during 3rd trimester but the severity is greatest when maternal infection is acquired during 1st trimester →Symptoms include abortion, intra-uterine death, stillbirth, prematurity, hydrocephalus, blindness, mental retardation, mcrocephaly, strabismus, blindness, petechiae, thrombocytopenia, anemia and thermal dysregulation, etc. →*Toxo triad - hydrocephalus, intracerebral calcification and choroidoretinitis* →*IgM and IgA found in newborn* ∙Infection in immune-competent host generally presents as flu or infectious mononucleosis-like →Most typical clinical manifestation is isolated cervical or occipital lymphadenopathy →Lymph nodes are not tender, do not suppurate, are usually discrete, and stay enlarged for <4-6 weeks Epidemiology - approx. 225,000 cases of T. gondii/year in USA ∙5000 hospitalizations and 750 deaths Oocysts are shed in cat feces for 7-21 days ∙Remain infective in soil for up to 1 year ∙Oocysts containing sporozoites are infective when ingested by mammals and give rise to the following stage: Tachyzoites Tachyzoites are highly pathogenic cysts ∙They disseminate via blood stream to infect CNS, eye, skeletal and heart muscle and placenta ∙They are transformed into bradyzoites Bradyzoites are dormant but viable forms and persist for the life of the host Route of infection ∙Ingestion of viable tissue cysts in inadequately cooked food/meat or ingestion of oocysts excreted by cats that contaminate that environment (soil, surface water) ∙Parenteral - via umbilical vein →Transfusion/transplantation, and transplacental Pathogenesis ∙Delayed type hypersensitivity after disintegration of cysts due to an extremely potent immune response ∙It is a strong and persistant Th1 response characterized by production of proinflammatory cytokines (IL-12, IF-γ, and TNF-α) Direct risk factors ∙Gardening and consumption of undercooked meat for primary toxoplasmosis infection ∙Ocular - class headlight in fog appearance is attributable to presence of active retinal lesions w/ severe inflammatory rxn →Most common cause of infectious uveitis worldwide Transplant recipients - a seropositive donor (D+) and seronegative recipient (R-) represent the highest risk for disease Disseminated disease = encephalitis, myocarditis, pneumonia, etc. Course of disease is variable ∙Asymptomatic → flu or infectious mono-like → disseminated disease depending on immune competency

Transcription of DNA viruses

Transcription and replication occur in the nucleus ∙With the exception of pox viruses (replicate in the cytoplasm because they bring their own polymerase with them; more complicated) Genome is the template for mRNA Virus uses the host cell DNA-dependent RNA polymerase and other host proteins that are already made More complex DNA viruses will encode their own polymerase Replication of DNA viruses

Diseases in which Type II hypersensitivity plays a prominent role

Transfusion rxns Hemolytic disease of the newborn Autoimmune hemolytic anemia, agranulocytosis and thrombocytopenia (individuals make autoimmune antibodies directed against their own blood cells) Certain drug rxn in which the drug binds to the surface of a cell, usually by complexing to some host cell protein, and creates a foreign epitope to which antibodies can be generated

Cytomegalovirus (CMV)

Transmission in many ways because occurs in body fluids (virus is present in blood, organs and secretions) ∙Exposure to contaminated saliva, blood transfusions, sexually transmitted, organ transplants, in utero, at birth, nursing (can cause congenital infections) Types of Infection at the cellular level ∙Productive infection is often asymptomatic →Fibroblasts, epithelial cells, macrophages, and others →Infection in organs such as kidneys & heart is usually asymptomatic (so most of the time you do not know when you were exposed) →Infection of ductal epithelial cells (excretion of virus in body fluids) ∙Latent infection: monocytes, stromal cells of the bone marrow, others ∙Reactivation of productive infection (shedding) →Usually asymptomatic, so host is not compromised →In immunocompromised, can cause serious disease ∙Neonate of surrogate negative mother causes Cytomegalic Inclusion Disease →The baby is at highest risk for this if the mother has a primary infection because she has no protective antibodies →During a secondary infection, the mother will have protection ∙During Multisite Symptomatic Disease, a person is immunosuppressed so is prone to reactivation of virus Mononucleosis-like Syndrome ∙Heterophile antibody negative mononucleosis (5-10% of cases of mononucleosis are due to CMV) ∙Symptoms tend to be less severe than EBV mononucleosis →Fever, fatigue, malaise, myalgias, headache, splenomegaly, but exudative pharyngitis & cervical lymphadenopathy are rare (unlike EBV mononucleosis) Congenital Infection ∙Most common viral cause of congenital disease ∙Reactivation during pregnancy →Maternal antibody is protective and the prolonged shedding of virus occurs as a result because child's immune system is not fully developed ∙Cytomegalic Inclusion disease: usually the result of mother having primary infection during pregnancy →Symptoms involved CNS and RES →20-30% mortality rate for severely infected infants →Diagnosis this by isolating virus from infants within a week after birth (with an in utero infection) →Permanent sequelae of infection: hearing loss, visual impairment and mental retardation are the most common consequences of congenital infection ∙If perinatal infection (after birth), will not isolate virus in urine until 3-4 weeks of age ∙Transmission: during birth, breastfeeding or transfusions ∙Usually no symptoms shown ∙Newborn of seronegaitve mother is at risk for clinical disease if exposed to CMV (pneumonia and hepatitis are more common manifestations of infection) Opportunistic infection ∙More common in AIDS patients and immunocompromised because at risk for serious disseminated disease ∙Pneumonia and encephalitis are common manifestations of infection ∙Retinitis and Colitis or Esophagitis are common manifestations of infection in AIDS patients ∙CMV is responsible for the failure of many kidney transplants (can also complicate heart, lung, liver, and bone marrow transplants) →This normally occurs when the donated organ is CMV + and the person receiving organ is CMV-

Indications for tests of O & P

Travelers Day-care attendees Migrant farm workers Institutionalized individuals Immune-suppressed patients

Treatment, Prevention & Control of C. tetani

Treatment requires debridement, antibiotic treatment (kill organism and reduce toxin production) Passive immunization with Tetanus immune globulin to neutralize unbound toxin Supportive therapy Prevention - vaccination with tetanus toxoid

VEGF may lead to higher interstitial pressure in tumors

Tumors are not composed entirely of malignant cells ∙In fact, less than half of a tumor's volume may be cancer cells, 1% to 10% may be blood vessels, and the remainder is interstitium, a collagen-rich matrix that surrounds cancer cells and separates them from the vasculature The vasculature induced by VEGF is leaky due to gaps between endothelial cells and openings within the cells themselves ∙Because of the hyperpermeable nature of VEGF-induced vasculature, fluid can leak from tumor vessels into the interstitium ∙The result is remarkably high interstitial pressure throughout the interior of a tumor, while pressure in the outermost areas remains at close to normal levels ∙By contrast, pressure in veins—the predominant vessels in tumors—is reduced in tumor veins compared with veins in normal tissue ∙Thus, there is a dual effect of increased interstitial pressure and decreased vascular pressure in tumors Since high molecular-weight molecules, including therapeutic agents, travel in large part by convection (from areas of high pressure to areas of low pressure), the high interstitial pressure of tumors can impede the delivery of therapeutic agents from the bloodstream to tumor cells

Tumor angiogenesis

Tumors cannot enlarge beyond 1-2mm unless they are well vascularized Perfusion supplies nutrients and oxygen Newly formed endothelial cells stimulate the growth of adjacent tumor cells by secreting growth factors and PDGF Angiogenesis also allows for metastasis ∙If blood vessels can get to tumor, tumor cells can get into blood Tumor vessels irregularly shaped and leak due to increased levels of VEGF Tumor vessels may grow continuously Tumors often have high levels of VEGF and FGF in serum and urine of CA pts ∙In other words, association b/w VEGF, angiogenesis, malignancy and metastasis has been established Angiogenic switch: when cells in tumor change to antigenic phenotype ∙May involve increased production of angiogenic factors or loss of angiogenic inhibitors ∙Tumors may also produce anti-angiogenic molecule to promote balance of pro- and anti-angiogenic stimuli ∙Angiostatin, endostatin and tumstatin produced in response to tumor

Angiogenesis is essential to tumor development

Tumors induce angiogenesis to obtain oxygen and nutrients 4 major steps of endothelial cells in angiogenesis ∙Breaking through of basal lamina that envelops existing blood vessels (to allow for proliferation) ∙Migration (of immature endothelial cells) towards angiogenic signal ∙Proliferation of endothelial cells ∙Formation of tubes (will eventually develop into blood vessel lumen) A number of pro-angiogenic growth factors, including VEGF, affect angiogenesis

Four types of sensitivity rxns

Type I ∙Predominantly IgE mediated ∙Typically soluble antigen ∙Effector mechanism involves mast cell, but also basophils and eosinophils ∙Examples: allergic rhinitis, asthma, systemic anaphylaxis Type II ∙IgG mediated ∙Associated w/ fixed molecules →Either cell or matrix associated antigen ∙Effector mechanism involves complement ∙Examples: drug allergies Type III ∙IgG mediated ∙To soluble antigen ∙Effector mechanism = complement, phagocytes ∙Examples: serum sickness, Arthus rxn Type IV ∙Mediated by T cells (Th1, Th2 or CTL) ∙Multiple antigens/mechanisms

Immune Complex Deposition

Type II (right) is uniformly deposited Immune complex (Type III) deposition is much less uniform b/c it is not being distributed in any particular manner

Type II hypersensitivity disorders

Type II hypersensitivity disorders are mediated by antibodies directed against antigens present in: ∙Cell surfaces ∙ECM ∙May be intrinsic to cell membrane or matrix ∙May be an exogenous antigen (such as a drug metabolite) that is absorbed onto cell or matrix

Clostridium perfringens Types A-E

Type dependent on combination of 4 lethal toxins Type A: responsible for most human infections ∙Ubiquitous Types B-E colonize the GI tract of animals, sometimes humans

Criteria for classification of viruses

Type of genome (DNA or RNA) Capsid morphology (Helical or icosahedral [spherical]) With/without an envelope (naked or enveloped) ∙Referred to as "DNA viruses" or "Naked icosahedral virus", etc.

Leprosy

Typically affects peripheral skin ∙Granulomas right underneath skin ∙Not a lot of necrosis in granuloma, but lots of damage in the area Lots of vessel growth in this area Granulomas localized to dermis of skin b/c of temperature ∙Core temperature is about 2 degree warmer ∙Bacteria will NOT grow at core temperature, so it is localized to dermis

B cell activation induces intracellular signaling events

Tyrosine kinase Protein kinase C Changes in gene transcription

Wound strength

Upon removal of sutures at end of first week - 10% strength of unwounded skin Increases rapidly over next 4 wks - 20% by 3rd wk At third month rate slows, 60% by 4th month ∙Plateau reached at 70-80% of original tensile strength Mature scar at 6-12 months (80% of original - defined now as maximal strength)

Use of ketorolac

Use for short term management of pain (b/c most likely given IM or IV) ∙Limited to 4-5 days ∙As effective in controlling pain as morphine

Bacterial vaccines are prepared from whole bacteria, toxins or capsular polysaccharides

Use whole bacteria, toxins (purified toxoids) and capsular polysaccharides ∙there is a sense that these are "better" There are very few live attenuated bacterial vaccines ∙BCG for TB (Mycobacterium tuberculosis) →Efficacy varies in different populations (not very effective) →Not used in the USA (b/c TB is not an endemic issue in US, and b/c vaccine is not terribly effective, and if vaccinated you may have positive TB test) ∙Salmonella →Defective in enzyme necessary for LPS synthesis, so decreased pathogenicity

Subunit vaccines

Usually an antigenic surface structure (that has been highly purified) ∙Induce neutralizing antibody ∙Prevent infection ∙Usually made by recombinant techniques ∙Hepatitis B vaccine (not always the greatest vaccine) ∙Human papilloma virus vaccine →Protects against HPV 6, 11, 16 and 18 →"Helps" protect against anogenital warts, precancerous cervical lesions, cervical cancer, anal cancers and anal intra-epithelial neoplasia

VEGF stimulates multiple downstream signaling pathways

VEGF binding induces multiple downstream signaling pathways Don't need to know specifics

What is VEGF?

VEGF is a critical cause of tumor angiogenesis

Environmental and cellular triggers induce the VEGF pathway

VEGF ligand production and subsequent angiogenesis can be triggered by a number of factors, including both genes and gene products, in the cellular microenvironment Hypoxia ∙Without an independent blood supply, tumors must rely on diffusion to obtain oxygen and other nutrients, and typically cannot grow more than 2 mm in size ∙Thus, a growing tumor without sufficient vasculature will have hypoxic—that is, lacking in oxygen—regions ∙In response to hypoxic conditions, tumors secrete a number of factors, including the VEGF ligand, in order to recruit new vasculature, which then provides a supply of oxygen ∙VEGF gene expression is up-regulated in response to hypoxic conditions Oncogenes ∙Oncogenes (genes that contribute to the production of a cancer) and tumor suppressor genes (genes encoding a protein that normally suppresses tumor formation) are associated with increased VEGF production ∙Oncogenes and tumor suppressor genes associated with VEGF include C-Src, Bcr-Abl, Ras, and p53 Cellular receptors ∙Additionally, some receptors on the surface of cancer cells may induce increased expression of the VEGF ligand, including epidermal growth factor receptor (EGFR), human epidermal receptor-2 (HER-2), and insulin-like growth factor 1 receptor (IGF-1R) Other growth factors and cytokines ∙Finally, the VEGF ligand, a growth factor and cytokine, may be produced in response to other growth factors and cytokines, including cyclooxygenase-2 (COX-2) and platelet-derived growth factor (PDGF)

VEGF ligand and receptor interactions

VEGF ligands mediate their angiogenic effects by binding to specific VEGF receptors, leading to receptor dimerization and subsequent signal transduction VEGF ligands bind to 3 primary receptors and 2 co-receptors ∙Of the primary receptors, VEGFR-1 and VEGFR-2 are mainly associated with angiogenesis ∙The third primary receptor, VEGFR-3, is associated with lymphangiogenesis Endothelial expression of VEGF receptors varies among the 3 primary receptors ∙VEGFR-2 is expressed on almost all endothelial cells, whereas VEGFR-1 and -3 are selectively expressed in distinct vascular beds ∙The neuropilin-1 (NP-1 or NRP-1) and NP-2 (or NRP-2) receptors are thought to increase the binding affinity of the various VEGF ligands to these primary receptors, although the specific roles of NP-1 and NP-2 in angiogenesis are not known While VEGF receptors are well known to be present on the surface of endothelial cells, recent research suggests that they may also be expressed by tumor cells ∙The significance of this finding requires further investigation This image depicts the various VEGF ligands interacting with the VEGFR family of receptors ∙VEGF ligands, shown in purple boxes, bind to their associated receptors, leading to receptor dimerization and subsequent signal transduction ∙For example, 2 VEGFR-2 receptors with bound VEGF ligands would dimerize and be activated, causing phosphorylation of the receptor tyrosine kinase domains and a subsequent cellular signaling cascade that leads to angiogenesis ∙Of the primary receptors, VEGFR-2 is thought to mediate the majority of tumor angiogenic effects

Angiogenic growth factors and receptors

VEGF: secreted by mesenchymal and stromal cells VEGFR-2: tyrosine kinase receptor present on endothelial cells and their precursors ECP: VEGF and VEGFR-2 stimulate endothelial cell precursors from bone marrow, increase proliferation of the cells at the site of angiogenesis ∙Delicate network formed, which matures Angiogenesis from pre-existing vessels stimulates proliferation and mobility of endothelial cells causing sprouting of new capillaries ∙FGF-2: enhances endothelial proliferation, differentiation and migration Stabilization of blood vessel: recruitment of pericytes, smooth muscle cells, disruption of ECM Angiopoietins 1 and 2, PDGF, TGF-beta also participate in stabilization ∙Angiopoietin 1: interacts with receptor on endothelial cells called Tie 2 to recruit periendothelial cells ∙PDGF: recruits smooth muscle cells ∙TGF beta: stabilizes newly formed vessels ∙Ang1/Tie2: mediates vessel maturation and maintains endothelial quiescence ∙Ang2/Tie2: loosens endothelial cells making them more responsive to VEGF and inhibitors of angiogenesis

Newer vaccines: Zoster

Vaccine licensed in 2006 for use in people aged 60 and over ∙Most effective at ages 60-69 ∙Vaccine prevents shingles in 50% of vaccinated individuals ∙*Vaccine prevents post-herpetic neuralgia in 67% of vaccinated individuals* Does not treat shingles or post-herpetic neuralgia

Functions of the VEGF family of receptors

Vascular endothelial growth factor receptor-1 (VEGFR-1) is a receptor for the VEGF ligand and can also bind VEGF-B and placental growth factor (PlGF) ∙VEGFR-1 is a key receptor in developmental angiogenesis (i.e. vessel formation during embryogenesis), but does not appear to be critical to pathogenic angiogenesis ∙Its role appears to vary with stages of development, physiologic and pathophysiologic conditions, and cell type VEGFR-2 mediates the majority of the downstream angiogenic effects of the VEGF ligand, including microvascular permeability as well as endothelial cell proliferation, invasion, migration, and survival ∙Recent work suggests that VEGFR-2 can stimulate angiogenesis on its own ∙The activation and signaling of VEGFR-2 may be positively or negatively influenced by co-expression and activation of VEGFR-1 VEGFR-3 promotes lymphangiogenesis and is found only in lymphatic endothelial cells in adults ∙There is also evidence that VEGFR-3 plays a role in maintaining vascular integrity by modulating VEGFR-2 activity

Angiogenesis from pre-existing vessels

Vasodilation, increased vascular permeability, degradation of ECM ∙Vasodilation - NO →NO is potent vasodilator but has relatively short half life, which is good, because we don't want too much stimulation of angiogenesis ∙Increase in vascular permeability - VEGF →VEGF plays large role in angiogenesis ∙Proteolytic degradation of basement membrane and disruption of cell-cell contact b/w endothelial cells by plasminogen activator Migration of endothelial cells Maturation of endothelial cells toward angiocentric stimulus (i.e. ischemia, tumor) Inhibition of growth and remodeling into capillary tubes Recruitment of periendothelial cells to support endothelial tube and form mature blood vessel

Polyenes

Very widely used to treat very severe systemic fungal infections ∙Problem is toxicity Anti-fungals that bind ergosterol Amphotericin B ∙Large lactone ring w/ both lipophilic and hydrophilic regions

Killed viral vaccine

Viral particles are chemically treated (formalin) or heated or irradiated ∙Influenza vaccine (injected) ∙Rabies vaccine ∙Salk polio vaccine (IPV - inactivated polio vaccine) Advantages ∙Safe ∙Does not cause disease Disadvantages ∙Must produce large amounts of virus →b/c no replication once inside body ∙Incomplete inactivation →made with pathogenic strain, so if made with incomplete inactivation it can be a problem ∙No replication of virus, therefore immunity may not be as "good"

Transcription of (-) strand RNA viruses

Virus encodes an RNA-dependent RNA polymerase ∙IS a core protein that is necessary to being transcription The genome is a template for mRNA A (+) strand copy of the genome is the template for genomic RNA

Parasite Specimen Processing

Wet mount of O & P (ova and parasites) is a specific request and is not done routinely ∙Stool should be collected in a waterproof, clean and dry container w/ a tight lid to avoid seepage and spillage ∙About 30mL of liquid specimen should be obtained on 3 alternate days for a better yield ∙Urine and water may destroy the trophozoites Alternatively, vials containing preservatives such as polyvinyl alcohol or formaldehyde may be used ∙Stool examination loses its sensitivity due to interfering substances such as barium, antibiotics, antacids, laxatives, antidiarrheals, iron, bismuth, mineral oil, recent enemas, urine and water Yield is better w/ fresh species ∙Organisms become refractory to staining in preserved specimen ∙Fecal specimens should not be incubated or frozen and thawed Barrier in specimen collection ∙Perceived low occurrence of disease ∙Lack of familiarity w/ the disease ∙Lack of effective Rx ∙Expense of testing ∙Poor patient compliance w/ stool ∙Collection

Antigen presenting cells deliver three types of signals to the T cell

When a naïve T cell binds the complex of processed peptide antigen and Class II MHC on the surface, an immunological synapse is formed *The first signal comes from the binding of processed peptide antigen, presented on Class II MHC, to the TCR* ∙Essential for activating T cells, and triggers a very complex series of intracellular signaling events that are discussed more fully later ∙As part of this activation signal, the co-receptor CD4 binds to an invariant, non-polymorphic area of the Class II MHC ∙It is important to know that these signaling events include: →Activation of protein kinase C and tyrosine kinases →Activation of GTP binding proteins →Changes in gene expression →→→Cytokines (specifically, growth factors) →→→Cytokine receptors →→→Other activation proteins ∙However, binding of the TCR complex is insufficient to activate T cells *The second, 'co-stimulatory' signal comes from the interaction of CD28 on the T cell w/ B7.1/B7.2 (also known as CD80/86) on the APC* ∙The interaction b/w CD28 and CD80/86 triggers the production of the growth factor cytokine IL-2 and high affinity IL-2 receptors that trigger autocrine and paracrine stimulation of clonal expansion of activated T cells ∙*CD80/86 is ONLY expressed on 'professional' APCs* ∙If the co-stimulatory signal is not received, this induces a state of non-responsiveness in the T cell called anergy *The third signal, which triggers differentiation, is largely a function of the cytokines present* ∙Different cytokines trigger the differentiation of activated CD4+ cells (see diagram) ∙The various types of effector CD4+ subsets vary in their function, i.e. the cytokines that they produce and by extension, the processes that they influence ∙The signature cytokines for each effector CD4+ types: →Th1: IFN-γ →Th2: IL-4 (IL-5 & IL-13) →Th17: IL-17

Complement and Fc-Receptor Mediated Inflammation

When antibodies deposit in extracellular tissues, such as basement membranes and matrix, resultant cell injury is due to inflammation ∙Not due to phagocytosis or cell lysis Deposited antibodies activate complement ∙Generate C5a (lesser extent C3a and C4a) which act as chemotactic factors and recruit neutrophils and monocytes →These cells can bind antibody via FcR or C3b via complement receptors and become activated →These factors also act as anaphylatoxins and increase vascular permeability Activated cells release prostaglandins, vasoactive peptides, other chemotactic factors, degradative enzymes, ROS ∙Cause tissue damage

Use of acetaminophen

Where aspirin and other NSAIDs are contraindicated ∙i.e. children w/ flu Used concomitantly w/ probenecid in treatment of gout

Several critical mechanisms are involved in tumor growth

While there are more than 100 distinct types of cancer (and considerable heterogeneity within each distinct tumor type), there exists a remarkable similarity in the pathologic traits that collectively drive tumor growth across most—if not all—malignancies Angiogenesis is 1 of the 6 acquired cellular capabilities leading to malignant growth

Direct and indirect pathways of allorecognition contribute to graft rejection

Why is this happening? Why do we have T cells that recognize someone else's MHC? Frequency of alloreactive T cells (~1 in 10) is much higher than self-foreign peptide combination (~1 in 1 million) ∙There are 2 pathways, direct and indirect Direct allorecognition ∙There is something about the foreign MHC. w/ whatever peptide is has in it, that mimics self+foreign ∙Can activate both cytolytic T cells and CD4+ T cells, leading to tissue damage, activated macrophages, etc. ∙Usually a dendritic cell in graft Indirect pathway ∙Graft cells can processed, end up phagocytized ∙Peptide antigen comes from graft MHC ∙Presenter = self MHC ∙This will turn on both CD4+ and CD8+ cells →CD4+ cells proceed as normal (make IFN-gamma, help B cells makes antibodies) →CD8+ cells have a problem w/ this b/c they cannot kill graft cells →→→Effector cells cannot get to graft b/c antigen is not presented to them in the right way

Angiogenesis: Hypoxia and HIF-1

Wound (tissue destruction) → decreased O2 Decreased O2 → HIF-1a → specific transcription Ex: VEGF→ Angiogenesis → increased O2 delivery to the tissue HIF-1 is a highly regulated transcription factor ∙Active as a dimer: →HIF-1a (expression highly regulated) →HIF-1b (expression constitutive) ∙In Normal O2 →Expressed a is hydroxylated on proline → ubiquitination and removal →Also, an inhibitor occupies cofactor binding sites ∙Under Hypoxic conditions →α is stabilized, dimerizes with β →Complex is phosphorylated and activated, binds cofactors, heads to nucleus →Upregulates expression of many genes HIF-1 as a transcription factor ∙Its Effects →Increases inflammatory response →Angiogenesis ∙In Inflammation phase: →PMNs and macrophage depend on anaerobic glycolysis → ATP →HIF-1 controls glycolytic switch, migration and bactericidal activity →HIF-1 controls myeloid differentiation to monos and macrophage ∙In Angiogenesis: →HIF-1 stimulates neovascularization and remodeling of existing vasculature →Controls transcription of VEGF, Angiopoeitin 2, SDF-1, and NO synthase

VZV: chicken pox or varicella

Zoster will occur in a dermatome in a unit of skin, with a particular neuron, and get reactivation Pattern of infection: ∙Inhalation of contaminated droplets leads to dissemination through lymphatics ∙This can infect T cells, liver, spleen, monocytes and cause Viremia (symptoms: fever, malaise, headache) ∙It then goes through the blood to mucus membranes and skin ∙The patient will have pustules, a classical symptom of chicken pox Chicken pox virus can present all over the body, whereas zoster will present wherever neurons have the latent infection Varicella pneumonia: can be severe in adults ∙Complication of chicken pox/primary VZV (not zoster) ∙Occurs in 20-30% of adults and can be fatal

Facultative organism

grow either in the presence or absence of O2

Ectoparasites

i.e. head lice, scabies, bed bugs They are restricted to the host's first line of defense and away from vital organs Factors for their survival: ∙Short duration of host exploitation ∙Utilization of group of hosts ∙Escape from a dead host

Foreign body mediated granuloma

i.e. methyl-methacrylate used as anchor for implants/joint replacements ∙it was found that our body reacts to this material basically an area where you did have a granuloma, but now its an abscess

Role of p56lck in early TCR-induced signaling

ln resting T cell ∙p56lck is inactive because of phosphorylation of a tyrosine in NEGATIVE REGULATORY site ∙CD4 not associated with TCR complex ∙ITAMs not phosphorylated When antigen binds to the a and b chains AND CD4 binds to Class II MHC ∙p56lck now adjacent to cytoplasmic tails of CD3 and z chains simultaneously CD45 (a surface tyrosine phosphatase) dephosphorylates and activates p56lck

Microaerophilic organism

utilize O2, but grow only in the presence of low O2

Amount of tissue loss

w/ large areas of tissue loss, scar formation will outweigh the regenerative capacity i.e. large ulceration or skin wound, rate of epidermal cell migration lags behind scar formation

Acute acetaminophen intoxication

w/in 12 hours ∙Nausea ∙Vomiting ∙Lethargy w/in 48 hours ∙Potentially fatal hepatic necrosis (dose-dependent) ∙High amount taken, the higher the risk ∙Renal tubular necrosis ∙Hypoglycemic coma

Aerotolerant anaerobes

will not utilize O2, but tolerate low levels of O2 *most clinically significant anaerobes are aerotolerant*

Dog, Cat & Human Bites

~1% of all ER visits ∙Among animal bites, 90% are dog bites ∙Cat bites more severe and have high proportion of osteomyelitis and septic arthritis Pasteurella multocida are small, gm (-) aggressive coccobacilli associated w/ mortality of 30% in septicemia ∙Complications are irreparable tissue damage and amputation ∙Rx = amoxicillin-clavulanate (500mg TID) for pts w/ infected dog/cat bite Capnocytophaga canimorsus is long thing fastidious gram (-) bacillus ∙Can cause fatal sepsis after animal bites in asplenic pts or pts w/ hepatic dz Management - rigorous wound toilet and appropriate antibiotic prophylaxis to all animal bites regardless of extent ∙Rx = amoxicillin-clavulanic acid Human bite pathogens = streptococci, S. aureus, Eikenella corrodens

Non-Spore Forming Gram (+) Rods

∙Actinomyces ∙Propionibacterium ∙Mobiluncus ∙Lactobacillus

Nationally Notifiable Parasitic Diseases

∙Cryptosporidiosis ∙Cyclosporiasis ∙Malaria ∙Trichinosis ∙Babesiosis

Immunosuppressive strategies

∙Cyclosporine ∙Tacrolimus (FK506) ∙Sirolimus (rapamycin) ∙Mycophenylate mofetil ∙Glucocorticoids (more in M1T3)

Clinical illnesses of gamma herpesvirus

∙Epstein Barr Virus ∙Infectious Mononucleosis ∙EBV-associated cancer ∙Human herpesvirus 8 ∙KS ∙B cell lymphomas ∙Multicentric Castleman's disease

Intoxication at higher salicylate levels

∙Generalized convulsions ∙Skin eruptions ∙Marked alterations in acid-base balance ∙Fever ∙*Dehydration* →Hyperpyrexia, sweating, vomiting and loss of water vapor during hyperventilation

Types of infection in all HSV

∙Genital herpes ∙Neonatal herpes ∙Herpetic Whitlow ∙Herpetic gladiatorum ∙Eczema hepaticum: severe skin infection ∙Meningitis and Encephalitis- CBN

Mild chronic salicylate intoxication

∙HA ∙Dizziness ∙Ringing in the ears (*tinnitus*) →Important b/c physicians used to increase dosage of aspirin in pt until this was present →Important for titrating dose ∙Difficulty in hearing ∙Dimness of vision ∙Mental confusion ∙Lethary ∙Drowsiness ∙Sweating ∙Thirst ∙Hyperventilation ∙N/V/D

Compromised hosts at risk for systemic infections

∙HIV ∙Transplant recipients ∙Cancer & leukemia patients ∙Diabetics ∙Patients on long term antibiotics ∙Catheterized patients (Candida, Malassezia furfur) ∙Burn patients (Candida; Aspergillus) ∙Individuals with chronic bronchitis or asthma (Aspergillus) ∙Patients receiving corticosteroid treatment

Clinical Illnesses in Alpha Herpesvirus

∙HSV-1 ∙HSV-2 ∙Herpes Keratitis ∙VSZ

Three types of graft rejection

∙Hyperacute ∙Acute ∙Chronic

Propionic acid derivatives

∙Ibuprofen ∙Naproxen

Steps in viral replication

∙Overview of the steps in viral replication →Pink text = antivirals (illustrates that the viral replication can be inhibited at really any step) ∙Recognition ∙Attachment ∙Penetration ∙Uncoating ∙Transcription ∙Protein synthesis ∙Replication ∙Assembly ∙Lysis and release

Pain substances

∙Potassium ∙Serotonin ∙Bradykinin ∙Histamine ∙*Prostaglandins* ∙Leukotrienes ∙Substance P

Anti-inflammatory/Analgesic agents

∙Salicylates ∙Para-aminophenol derivatives ∙Proprionic acid derivatives ∙Heteroaryl acetic acids ∙Enolic acids ∙Indole and indene acetic acids

Salicylates

∙Salicylic acid ∙Aspirin ∙Diflunisal

WHO's list of "elimination of parasitic diseases"

∙Trypanosomiasis ∙Schistosomiasis ∙Onchocerciasis ∙Leishmaniasis ∙Malaria Currently, there are no vaccines against parasitic infections

Delayed Dx of RMSF and poor outcome

∙Waiting for petechial rash to develop ∙Misdiagnosing as gastroenteritis ∙Ruling out as no H/O tick bite ∙Inappropriate geographic exclusion ∙Inappropriate seasonal exclusion ∙Failing to treat on clinical suspicion ∙Failing to elicit appropriate history ∙Failing to treat w/ doxycycline

Definition of a Type I hypersensitivity rxn

"Immediate or Type I, hypersensitivity is a rapid immunologic reaction occurring within minutes after a combination of an antigen with antibody bound to mast cells in individuals previously sensitized to the antigen."

Scabies

"the 7-year itch" Etiology = Sarcoptes scabiei (almost invisible itch mite), great imitator Transmission = body-to-body contacts (Shaking/holding hands) or by sharing infested person's clothes ∙Incubation period is 3 weeks ∙Epidemics occur in families, hospitals, nursing homes, orphanages Symptoms: pruritus (worse at night), erythematous papules ∙Pruritus is due to hypersensitivity phenomenon to mite antigen(s) Norwegian scabies appears as crusted (hyperkeratotic lesions) ∙Crusts are heavily infested w/ mites and are very contagious ∙Burrows are short, wavy, raised tracts containing female mite and pathgnomic (tunnel of love) →Condiminium or layered appearance could be in the form of disseminated dermatologic manifestation DDX: excoriated eczema, dermatitis, urticarial, insect bites, lupus, drug rxn, hives, folliculitis, impetigo, rosacea, and psoriasis Dx: time honored adage = if it scales, scrape it ∙Scrape burrow w/ scalpel blade 15 covered w/ mineral oil or saline or KOH, smear it on slide and examine under microscope for mites, mite eggs, and fecal pellets (scybala) ∙Felt tip marker applied to skin concentrates in tunnels thus highlighting the burrows Rx: benzyl benzoate, sulfur ointment, permethrin (elimite 5% cream), systemic ivermectin (stromectol), crotamiton (10% lotion or cream) and lindane ∙Lindane should not be used after bath or shower, in pregnant and lactating women and in young children and w/ extensive dermatitis ∙Seizure and aplastic anemia have been reported after lindane use The household and sexual contacts should able be treated, including regular guests, to avoid ping-pong infections ∙Wash all clothes, bedding and towels in hot water and dry them in hot drier Pearl - be sure to tell patient to apply the scabicide lotion under fingernails ∙Eggs tend to collect there from scratching and can easily be spread to other parts of body

Transcription of retroviruses

(+) strand RNA is transcribed into DNA ∙Reverse transcriptase (RNA-dependent DNA polymerase) is a core enzyme ∙Is the reverse of what normally happens (DNA from RNA) DNA travels to the nucleus where it integrates into the host chromosomes Transcription of DNA produces mRNA and genomic RNA

The relationship of CD4+ Th1 cells and macrophages

*Activated CD4+ T cells, when influenced by IFN-γ and IL-12, differentiate into Th1 cells, whose signature cytokine is IFN-γ ∙One of the major roles of CD4+ Th1 effector cells is to induce macrophage activation* As you remember, macrophages have receptors that bind to bacteria and other pathogens. These facilitate: ∙Phagocytosis ∙Destruction ∙Intracellular degradation (antigen processing) Effects of an activated CD4+ Th1 effector cell on macrophages include: ∙Cause phagosomes that contain captured microorganisms to more efficiently fuse with lysosomes ∙Cause synthesis of highly reactive and microbicidal molecules →Oxygen radicals →NO →Proteases ∙Increased expression of: →Class II MHC →B7 →CD40 →TNF-R

Sexual vs. asexual states of fungi

*Fungal form producing sexual spores is termed the teleomorph Fungal form producing asexual spores is termed the anamorph* Some fungi have 2 names, one for each form ∙Originally thought to have been 2 separate organisms Anamorphic (asexual) state is isolated from clinical specimens *Asexual designations = common name - used in clinical settings*

Adaptive immunity against extracellular bacteria

*Humoral immunity is the principal protective immune response against extracellular bacteria* ∙Functions to: →Block infection →Eliminate microbes →Neutralize toxins ∙Neutralizing antibody →May be all that is needed for protection if the organism is pathogenic only b/c of a single toxin or adhesion molecule →IgA and IgG ∙Activation of complement (classical) →IgM and certain subclasses of IgG ∙Opsonizing antibody →Together w/ complement can kill bacteria w/ an other exposed lipid bilayer (gram -) →IgG ∙*Ultimately, most extracellular bacteria are removed by phagocytes* The protein antigens associated w/ extracellular bacteria also activate CD4+ T cells ∙Produce cytokines that promote local inflammation →Defective Th17 cells are associated w/ increased susceptibility to bacterial and fungal infections (Job's syndrome) ∙Enhance phagocytic and microbicidal activity of macrophages and neutrophils →May be at least in part due to activation of Th1 cells and production of IFN-γ ∙Stimulate antibody production

Mechanism of aspirin

*Irreversible inhibition of cyclooxygenase* ∙Means that action lasts as long as it takes to synthesize new COX

Effector CTL induce apoptosis

*Once activated, CTL must be able to recognize antigen on a non-professional APC* ∙Virally-infected cell ∙Tumor cell Cytotoxins contained in lytic granules ∙*Perforin* →Protein analogous to C9 →*Polymerizes to create transmembrane channels* →Allows granzymes to enter ∙*Granzymes* →Family of serine proteases →Cleave cellular proteins →Activate endonuclease (activates effector caspases) →Induce apoptosis *Fas-FasL interaction (induces apoptosis like all members of the TNFR superfamily)*

Metabolism of acetaminophen

20-50% plasma protein bound 90%+ is conjugated in liver w/ glucoronic acid, sulfuric acid or cysteine ∙*Small portion is metabolized by the liver microsomal enzymes (p450 system)* ∙Important b/c of side effects (hepatotoxicity)

Cell mediated immunity

3 major topics: ∙Effector CD4+ cells and activation of cytotoxic macrophages ∙The generation of CD8+ cytolytic T cells (CTL) and their mechanisms of action ∙How NK cells are activated for killing and their regulatory role in cell mediated immunity

Serology (antibody detection) in fungal infections

4-fold increase in IgG titer indicates recent infection IgM indicates acute infection Antibody titers ∙Usefulness is limited by a lack sensitivity & specificity for many fungal pathogens Antibody detection of histoplasmosis, blastomycosis & coccidioidomycosis are currently available

Metabolism of aspirin

80-90% plasma protein bound ∙competes w/ thyroxine, penicillin, phenytoin, naproxen, sulfinpyrazone and bilirubin hydrolyzed to salicylate (salicyclic acid) in the plasma

Metabolism of Diflunisal

99% bound to plasma albumin *Competes w/ oral hypoglycemic (drugs that type II diabetics take, i.e. metformin) and anticoagulants (warfarin, Coumadin)* ∙Will need to make adjustments in doses of these drugs in certain pts

Metabolism of naproxen

99% bound to plasma proteins No interaction w/ oral hypoglycemic or oral anticoagulants

Metabolism of ibuprofen

99% bound to plasma proteins No interaction w/ oral hypoglycemic or oral anticoagulants ∙Much safer for diabetics, patients on warfarin

Metabolism of ketorolac

99% plasma protein bound Little, if any, interaction w/ other bound drugs

Wound healing

A complex and cooperative process of several overlapping stages These stages involve: ∙Cell and their secretions ∙Cell recruitment and their migrations ∙Erection and dismantling of successive scaffolds ∙Cell proliferation and cell apoptosis Wound healing differences: ∙Post-gestational involves repair ∙Pre-gestational (fetal) is regenerative

Mycelium

A mass of intertwined hyphae

Transcription of (+) strand RNA viruses

A virus whose sequence is the same as the mRNA of that virus Genome can function as an mRNA ∙Translated into a polyprotein and then cleaved into individual proteins Virus encodes an RNA-dependent RNA polymerase on its polyprotein ∙Is NOT a core protein because it is not packaged into the capsid when it replicates Transcription produces (-) strand RNA ∙Template for mRNA ∙Template for genomic genomic RNA

Wound = tissue destruction

A wound disrupts: ∙Epithelial cells →Epidermis →Dermis →Organ tissues ∙Blood vessels (can lead to hypoxia) ∙Connective tissue (and therefore tissue scaffolding) ∙Dermal appendages (hair follicles, sebaceous glands)

Kaposi Sarcoma: prevent apoptosis so infected cells won't self destruct

AIDS defining disease KSHV sequences associated with KS at all stages of tumor formation and with both AIDS related and non AIDS related KS 17% of HIV and KSHV co infected patients will develop KS Viruses expresses proteins with homology to cellular proteins that promote growth and inhibit apoptosis so similar to other herpes viruses

Ibuprofen (Motrin, Rufen)

ALL 4 A's: analgesic, anti-inflammatory, antipyretic, antiplatelet (reversible)

AP-1 in T cell activation

AP-1 is a transcriptional factor that is very important for TCR-initiated changes in gene transcription AP-1 is a complex of Fos and Jun Fos must be de novo synthesized ∙Synthesis is regulated by MAP-K and PKC pathways Jun exists in cytoplasm in inactive form ∙Activated by phosphorylation via the Jun-N-terminal kinase, JNK (or stress activated protein, SAP) ∙JNK is activated by another small G protein called rac!

Free Living Amoebae

Acanthamoeba - causes necrotic skin ulcers and amoebic keratitis in contact lens wearers (eye pain/redness, blurred vision, sensitivity to light, FB sensation, excessive tearing) Naegleria fowleri - causes meningo-encephalitis ∙One should avoid swimming and diving in small lakes and ponds

Para-Aminophenol Derivatives

Acetaminophen (Tylenol)

Numerous solid tumors overexpress VEGF ligand

Across a wide range of human tumors and/or cell lines, expression of VEGF has been shown to lead to the development and maintenance of a vascular network that promotes tumor growth and metastasis A large and growing body of evidence shows that VEGF gene expression and VEGF production is associated with a range of solid tumor types and with poor prognosis VEGF is also expressed by certain cell lines derived from a wide variety of lymphomas and leukemias

Rofecoxib (Vioox)

Action: anti-Inflammatory, analgesic, antipyretic REMOVED FROM MARKET DUE TO HEART ATTACK AND STROKE RISK Metabolism ∙Half-Life approximately 17 hours ∙Metabolized by cytosolic enzymes in the liver ∙Cytochrome P450 plays a minor role ∙Oral bioavailability is approximately 93% ∙No effect on bleeding time for single dose or daily dosing for up to 12 days Special Notes ∙No effect on the anti-platelet activity of low-dose aspirin (81 mg once daily) ∙NOT a substitute for aspirin for cardiovascular prophylaxis ∙Increased risk of GI ulceration with concomitant admin of low-dose aspirin

Diclofenac (Voltaren)

Actions: Analgesic, anti-inflammatory, anti-pyretic Uses ∙Approved for long term treatment of rheumatoid arthritis, osteoarthritis and ankylosing spondylitis ∙Some use for postop pain, bursitis, acute musculoskeletal injury Mechanism of action ∙Competitive inhibitor of COX ∙Reduces intracellular concentrations of free arachidonate in leukocytes Metabolism ∙99% plasma protein bound ∙(Minimal competition with warfarin, no affect on oral hypoglycemics) ∙50% first pass effect Side effects ∙20% experience, 2% discontinue ∙Epigastric pain, also nausea and emesis ∙Gastric ulceration ∙CNS effects (tinnitus, nervousness, anxiety, drowsiness) ∙Skin rashes, allergic reactions

Acetaminophen (Tylenol)

Actions: analgesic, antipyretic ∙Weak anti-inflammatory effect

Actions of chemokines

Activate adhesion molecules Act through G protein-coupled transmembrane receptors and cause Ca2+ influx (actin effect) Induce haptotaxis (cell migration along surface gradients) Bind to proteoglycans and ECM Induce oxygen burst

Activation of ZAP-70

Activated p56lck phosphorylates ITAMS on CD3 and z chains Once ITAMs in the z chain are phosphorylated by p56lck, they become "docking sites" for proteins including ZAP-70 ZAP-70 gets tyrosine phosphorylated by p56lck (or by the ZAP-70 itself) and activated

The VEGFRs differ in their downstream signaling effects

Activation of vascular endothelial growth factor receptors (VEGFRs) can stimulate the expression of factors important for angiogenesis, including anti-apoptotic proteins, cell adhesion molecules, VEGFR-1, and matrix metalloproteinases (MMPs) ∙A large body of evidence suggests that VEGFR-2 is the most important of the VEGF receptors with regard to angiogenesis, with postreceptor signaling pathways that promote endothelial cell division, permeability, and survival ∙However, there seems to be a great deal of cross-talk in the signaling pathways—still only partially understood—that ultimately translates VEGF receptor binding into angiogenesis ∙According to Dr. Didier Picard of the University of Geneva, "Signaling cross-talk refers to a situation where one signal affects the output of another, seemingly distinct, signal transduction pathway." As shown on this slide, the mitogenic, angiogenic, and permeability-enhancing effects of VEGF are primarily mediated through VEGF receptor-2 (VEGFR-2), which undergoes dimerization and phosphorylation following ligand binding ∙This activity promotes the proliferation, migration, and survival of endothelial cells ∙Specifically, the downstream signaling effects of VEGFR-2 binding include integrin activation via the PI3K/Akt pathway, as well as activation of the Raf/MEK/Erk pathway to induce endothelial cell growth

Types of clinical infection in the host cell

Acute infection ∙Infection remains localized →Productive infection at the site of entry →Virus is cleared by the immune response →Acute disease →→→Symptomatic illness →Asymptomatic or subclinical infection →→→Infected individuals can shed the virus →Characteristics of a localized infection →→→Self-limiting →→→The site of entry is often a mucosal surface →IgA provides protection at these surfaces →→→Immunity is often short-lived and not life-long →→→Usually viruses cause a respiratory tract infection or gastroenteritis ∙Localized infection that disseminates →Productive infection at the site of entry →→→May be asymptomatic →Spread via lymphatics, blood or neurons →Replication occurs at a secondary site with characteristic symptoms →Secondary viremia is possible →Enteroviruses, measles, mumps, rubella, varicella (chicken pox), parvovirus B19 ∙Disseminated infection →Virus shedding typically occurs following initial replication →→→Patient is infectious before the illness is recognized →Incubation period occurs as the virus disseminates →A prodrome is the non-specific flu-like symptoms the patient can experience as the virus disseminates →Symptoms correlate with the replication at the secondary site and is the first time the illness is recognized →IgG is important for immunity against these types of viruses →→→Immunity conferred is usually life-long Latent infection/reactivation ∙The initial infection occurring upon the acquisition of the virus is the primary infection →The virus may remain localized or it might disseminate →May be symptomatic or asymptomatic ∙Latent infection →Virus is not detected and the patient is asymptomatic ∙Reactivation of a productive infection →May be asymptomatic or symptomatic →Secondary infections are cleared more rapidly than primary infections ∙Seen in Herpes virus and HPV Chronic infection ∙Acute infection, then a carrier state ∙Virus persists over time and can be productive OR nonproductive at the cellular level ∙Productive means that the virus is shedding over time →At the cellular level the host cell is not destroyed by the infection →At the tissue level only a few cells in the population are infected ∙Nonproductive →Latency or transformation →Reactivation of a latent virus results in a productive infection →Virus-induced immortalization of cells increases the risk of the cells acquiring mutations that can result in transformation ∙Chronic infection can lead to persistent shedding →Continual low-level shedding of the virus →→→Patient becomes a carrier that is infectious even if asymptomatic →→→Patient may develop clinical disease over time →Seen in chronic hepatitis B or C and HIV Transformation Cancer induced by viruses

Contraindications of ketorolac

Additive side-effects w/ other NSAIDs Partial or complete syndrome of nasal polyps, angioedema and bronchospasm Previously demonstrated hypersensitivity to ketorolac

Chronic LD/ Post LD Syndrome

After appropriate Rx, a small number of pts continue to have subjective symptoms, like musculoskeletal pain, neurocognitive difficulties or fatigue

Leptospirosis

Aka canefield fever, rice-field fever Rodents most important and widely distributed reservoirs ∙Once infected, shed organism in urine for their lifetime Characterized by biphasic presentation w/ influenza-like illness and conjunctivitis, followed by meningitis, uveitis, rash or hepatorenal dysfunction ∙Several icteric type = Weil's disease Leptospira interrogans are highly motile, obligate aerobes requiring LCFA Epidemiology - direct exposure to urine of infected animals or urine-contaminated water and soil, through recreational or occupational activities represents main source of infection ∙Leptospirosis is maintained by persistent colonization of proximal renal tubules of carrier animals Risk factors - cattle and pig farmers, slaughterhouse workers, miners, sewer maintenance, veterinarians, dairy farmers, soldiers, hunters, fishermen, shepherd, hikers, swimming or boating in freshwater lakes formed by runoff or damming Pathogenesis - vasculitis, mainly of small vessels which leads to fluid and cell leakage and eventually to frank hemorrhage is considered most characteristic lesion ∙Thrombocytopenia also common Incubation period is 2-30 days Clinical features ∙Septicemic phase (petospiremic) - sudden onset of generalized and throbbing severe HA, retroocular pain, muscle pain and tenderness, high fever, nausea, *conjunctival suffusion* (hallmark diagnostic sign), transient skin rash, photophobia and meningism →Bacteria can be isolated from blood, CSF ∙Immune phase (leptospiuric) - gives saddle-shaped pattern of fever chart, serum CPK levels elevated (indicating skeletal muscle inflammation →Sore throat, dry cough, hemoptysis, pulmonary edema, ARDS, aseptic meningitis →Hepatomegaly common →ESR raised, CSF lymphocytosis is rule →Pt appears delirious, confused, disoriented or semicomatase →Bacteria can be isolated from urine ∙Biphasic illness - anicteric form and fulminant icterohemorrhagic form ∙Weil syndrome - associated w/ severe hepatic malfunction, marked jaundice, high fever, hemorrhages, hemolytic uremic syndrome and systemic involvement →Yellowish-reddish tinge (rubinic jaundice) seen w/ bilirubin levels of >15mg/100cm^3 and azotemia ∙Complications - pulmonary hemorrhage, renal failure, widespread hemorrhage, chronic fatigue, CV collapse, mood swings, depression ∙Rx: penicillin or tetracycline/doxy

Tularemia

Aka rabbit fever, deer-fly fever, tick fever Occupational hazard for lab workers, landscapers, farmers, vets, hunters, trappers, cooks and meat handlers Extreme infectivity (infectious dose only 1-10 organisms) ∙Easily disseminated ∙Transmitted by all 5 traditional modes: ingestion, inhalation, direct contact, arthropod intermediates and animal bites Has capacity to cause illness, death The ticks Amblyomma americanum, Dermacentor andersoni and D. varabilis transmit disease ∙Handling contaminated animal tissues/fluids, contact or ingestion of contaminated water, food or soil or aerosol can also transmit disease Incubation period is 3-5 days Tularemia is an acute, febrile, granulomatous infectious zoonosis Clinical features: forms are ulceroglandular, glandular, oculoglandular, oropharyngeal, pneumonic, typhoidal, and septic ∙Typhoidal form - marked by triad of oval opacities, hilar adenopathy and pleural infiltrates →This is an acute and undifferentiated febrile illness w/ incipient pneumonia, pleuritis, cough and substernal burning, HA, chills, rigors and generalized body ache, sore throat and respiratory failure →There is pulse temperature dissociation (relative bradycardia) →No person-to-person transmission ∙Ulceroglandular - characterized by painful skin ulcer and lymphadenopathy, and lymphadenitis →Nodes may become fluctuant and rupture ∙Oculoglandular - occurs when blood from a compressed tick sprayed in the eye or by direct contamination →Onset usually abrupt w/ chills, fever, HA, muscle pains, dry cough, malaise, skin changes, lymphadenopathy of head/neck CXR - reveals ill-defined infiltrates, hilar adenopathy and pleural effusion ∙EIA, PCR and FA can be used in diagnosis Rx: streptomycin, gentamicin, doxy and fluoroquinolones are the options

Brucellosis

Aka undulant fever, Malta fever Chronic granulomatous infection caused by intracellular bacteria Multiple organisms cause ∙Gram (-), slow growing, intracellular coccobacillus, oxidase (+), catalase (+), urease (+) ∙BSL-3 pathogen ∙Colonies non-hemolytic, non-pigmented and convex Transmission - by ingestion, inhalation, skin penetration, and consumption of unpasteurized dairy products ∙Incubation 5 days - 6 months ∙No person-to-person transmission Virulence factor is LPS ∙Bacterium does not bear classic virulence factors (exotoxin or endotoxin) ∙Tendency to invade and persist in human host through inhibition of programmed cell death ∙Occupational disease in shepherds, abattoir workers, vets, dairy-industry professionals, and microbiology lab personnel Clinical features ∙Intermittent spiking fever, rigors, profuse sweating, HA, malaise, muscle and back pain ∙Malodorous perspiration is almost pathognomic ∙Pts may present w/ swollen testicles ∙Organism is localized in spleen and bone marrow ∙Endocarditis accounts for majority of Brucella-related deaths ∙Chronic form can manifest as chronic fatigue syndrome, w/ episodes of depression, hepatitis, endocarditis, arthritis, spondylitis, sacroiliitis, infections of large joints and vertebral osteomyelitis ∙Lymphadenopathy, hepatomegaly, splenomegaly often present ∙Pregnant women at risk of spontaneous abortion ∙Pons sign - seen on plain radiography as steplike erosion of antero-superior vertebral margin Most commonly reported lab-associated bacterial infection Dx: bone marrow culture gold standard ∙Can also use serum agglutination test ∙Circulating Brucellae easily detected by blood culture Rx: tetracycline, doxy, rifampin (for 6 weeks) streptomycin (2-3 weeks, TMP-SMX

Tolmetin (Tolectin)

All 4 A's: analgesic, anti-inflammatory, anti-pyretic, prolongs bleeding time Less occult blood loss than aspirin Uses of Tolmetin ∙Used to treat rheumatoid arthritis and osteoarthritis Mechanism of Action of Tolmetin ∙Competitive inhibitor of COX Metabolism of Tolmetin ∙99% plasma protein bound ∙Does not compete w/ warfarin or oral hypoglycemic agents Side Effects ∙25-40% experience, 5-10% discontinue ∙15% epigastric pain, nausea and emesis ∙Gastric and duodenal ulceration ∙CNS effects (tinnitus, nervousness, anxiety, drowsiness)

Piroxicam (Feldene)

All 4 A's: analgesic, anti-inflammatory, anti-pyretic, prolongs bleeding time ∙Equivalent to aspirin, indomethacin or naproxen, but much better tolerated Uses ∙Osteoarthritis ∙Rheumatoid arthritis ∙Acute gout Mechanism of Action ∙Potent inhibitor of COX ∙Also inhibits activation of neutrophils and hemostasis Metabolism ∙99% plasma protein bound ∙May compete w/ warfarin ∙Enterohepatic recycling Side effects ∙11-46% experience, 4-12% discontinue ∙GI symptoms, 1% incidence of peptide ulcers

Ketorolac (Toradol)

All 4 A's: analgesic, anti-inflammatory, anti-pyretic, prolongs bleeding time (reversible 24-48 hr)

Naproxen (Naprosyn, Anaprox)

All 4 A's: analgesic, anti-inflammatory, antipyretic, antiplatelet (reversible) Advil = naproxen

Prophylaxis against HDN

All Rh- mothers are given Rhogam at 28 weeks gestation and again w/in 72 hours of childbirth ∙It is also used in Rh- mothers after abortion or miscarriage Rhogam is a sterile preparation of IgG specific for the RhD antigen ∙Upon administration, this IgG will bind to any fetal RBC that have entered the maternal circulation and opsonizes them for clearance before the mother can mount her own immune response ∙It is thought that, despite the fact that this preparation is IgG and can cross the placenta, the amount of Ig that is given therapeutically is insufficient to cause destruction of fetal RBCs but is sufficient to clear any fetal RBC in the maternal circulation

Chemokines

All are 8-12kD polypeptides containing two internal disulfide loops About 40-50 different chemokines Classified on basis of number and location of N-terminal cysteine residues ∙There are 2 major groups →CC: Cysteines are adjacent →→→Act on monocytes, lymphocytes, and eosinophils →CXC: cysteine residues separated by one AA →→→Act on neutrophils →→→CXCL8 (IL-8): recruits neutrophils from blood to infected area →Others (C or CXXXC) Biologic function ∙Recruit cells to sites of infection ∙Regulate the traffic of leukocytes and lymphocytes through peripheral lymphoid tissue ∙Promote angiogenesis and wound healing ∙Involved in development of diverse non-lymphoid organs

First step in priming: Activation of Th2 cells

Allergen presented to Th2 cells by APC (dendritic cells) ∙Processing enhanced by enzymatic activity of allergen? ∙Drives Th0 cells to differentiate into Th2 cells ∙Promoted by IL-4 (either made by activated mast cells or by other Th2 cells) When activated, Th2 secrete: ∙IL-4 →Favors Ig class switching to IgE →Stimulates Th2 differentiation ∙IL-5 →Activates eosinophils ∙IL-6 ∙IL-10 ∙IL-13 →Promotes IgE production and mucus secretion

Graft rejection, in the absence of immunosuppression, occurs in:

Allografts Xenografts Image shows number of *mismatched* HLA alleles vs. organ survival ∙Remember that HLA alleles matched are HLA-A, HLA-B, and HLA-DR

Clostridium perfringens: Lethal toxins

Alpha toxin (Type A) Phospholipase C (lecithinase) ∙Lyses endothelial cells, RBCs, WBCs, and platelets ∙Increases vascular permeability, bleeding, tissue destruction β toxin (Type C) ∙Necrotizing activity in intestinal mucosa ε toxin ∙Increase vascular permeability of GI wall ι toxin (Type E) ∙Necrotizing activity & increases vascular permeability

3 Classes of Herpesvirus

Alpha, Beta, and Gamma herpesviruses ∙Alpha Herepesviruses (HHV-1, HHV-2, HHV-3) →Latent infection is in different cell type than productive infection ∙Beta Herpesvirus (HHV-5, HHV-6, HHV-7) ∙Gamma Herpesviruses (HHV-4, HHV-8) →Beta and Gamma tend to have latent infections in the same cell type as productive infection

Graft vs. Host Disease (GVH)

An issue anytime transplanted tissue has donor's T cells in it ∙T cells go wild, start to recruit recipient macrophages Occurs most frequently with allogeneic bone marrow grafts Can follow transplantation of any solid organ rich in lymphoid cells ∙Liver ∙Unirradiated blood Recipient usually immunosuppressed ∙Disease itself ∙Treatment (irradiation, chemo)

Sites colonized by anaerobic organisms

Anaerobic Gram (-)'s are most common residents of skin and mucus membranes Mucosal surfaces ∙Colon →Up to 500 species of anaerobes can be in a fecal specimen; only a few are associated with infection ∙Female genital tract ∙Oral cavity →Gingival crevices, tonsillar crypts, tooth surfaces Hair follicles Growth of anaerobes is facilitated by facultative organisms Aerotolerant anaerobes can co-colonize with facultative organisms Anaerobes:aerobes ∙>1000:1 in the oral cavity & colon ∙~10:1 in the female genital tract

Endothelial precursor cells

Angioblast-like cells sotred in adult bone marrow Quiescent until recruited to tissue to initiate angiogenesis Express markers for hematopoietic stem cells and endothelial specific markers Participate in replacement of lost endothelial cells, reendothelization of vascular implants, cutaneous wounds and tumors

ECM Proliferation

Angiogenesis needs mobility and migration of endothelial cells to form new blood vessels Integrins: form and maintain new blood vessels Matricellular proteins: destabilize cell matrix interactions and promote angiogenesis Proteinases: plasminogen activator and metalloproteinases remodel tissues during endothelial invasion ∙Also release VEGF, FGF-2

Mechanisms involved in rejection of (kidney) allografts

Antibody-mediated rxns ∙*Major mechanism in hyperacute graft rejection* ∙Also can play a role in acute and chronic graft rejection ∙Causes injury by: →Complement-dependent cytotoxicity →Inflammation →Antibody-dependent cellular cytotoxicity T-cell mediated rxns ∙*Major mechanism in acute and chronic graft rejection* →If called upon to make a choice b/w B and T cells as mechanism for graft rejection, pick T CELLS

The T Cell Receptor Complex

Antigen binding by the TCR a and b chains ∙No cytosolic domains CD3 ∙Two heterodimers ∙ITAMs z chains ∙Mostly cytosolic ∙Have ITAMs ITAMs ∙Immunoreceptor tyrosine-based activation motifs ∙Sites for regulatory tyrosine phosphorylation →Positive →Negative ∙Present on the cytoplasmic tails of all CD3 proteins (g, d, e and z)

T-independent antigens

Antigen has repeating subunits ∙Causes extensive BCR cross-linking ∙Ex: pneumococcal polysaccharide, Salmonella flagellin Antigen can directly stimulate B cell at high concentrations ∙Binds to B cell via surface marker distinct from surface Ig ∙Ex: bacterial LPS Polysaccharides are often TI antigens ∙Can be made T-dependent if conjugated to a protein ∙Implications for vaccine T-independent antigens cause proliferation and IgM secretion in absence of T cel help ∙*b/c no T cell help → little to no class switching, little to no memory*

Immune complex mediated hypersensitivity (Type III)

Antigen-antibody complexes produce tissue damage mainly by eliciting inflammation at sites of deposition Typically, type III hypersensitivities when antigen combines w/ antibody w/in circulation as circulating immune complexes, which then often deposit into vessel walls Sometimes, however, immune complexes are formed w/in tissue (extravascularly) The antigens that elicit type III rxns can be exogenous (foreign) protein or endogenous protein (which is autoimmune)

Mechanism of action of acetaminophen

Antipyretic ∙Blocks COX in hypothalamus only in environments w/ low levels of peroxides ∙NOTE: *high concentrations of peroxides in inflammatory lesions → we do not see effects in inflamed regions* Analgesic - unknown

Antivirals & Herpesvirus

Antivirals are nucleoside analogues that inhibit productive herpesvirus replication Upon entering the cell, they need to be phosphorylated by a viral enzyme The advantage is that they will only become activated in an infected cell, which results in fewer issues with toxicity ∙Mechanism →Get incorporated into DNA →Competitively inhibit polymerases Acyclovir: a guanosine analogue ∙Mechanism of action: →1st phosphate added by thymidine kinase (TK), which is a virus specific enzyme, 2nd and 3rd phosphorylation added by cellular enzymes →*When Acyclovir is incorporated into DNA, this results in chain termination (because it competitively inhibits dGTP for insertion into DNA →→→If it lacks a 3'-OH group, cannot accept a base)* →Herpes Simplex Virus (HSV) TK more efficient at phosphorylating acyclovir than Varicella Zoster Virus (VZV), so TK more active against HSV than VZV →Cannot be used for Cytomegalovirus (CMV) infection because CMV doesn't encode TK →*Acyclovir inhibits the productive infection, but not the latent infection* ∙*Resistance to acyclovir* →Loss of genes encoding TK →→→Resistant viruses are less virulent so don't replicate as well →→→Less of a problem clinically →Mutation in thymidine kinase (TK) reduces its affinity for acyclovir →Mutation in DNA polymerase →→→Inhibits binding to acyclovir triphosphate →→→Viruses must retain their virulence so they are clinically significant →Often seen in immunocompromised individuals with recurrent HSV (ex: those with HIV), necessitating prolonged acyclovir treatment Other nucleoside analogues: ∙*Valacyclovir* →hydrolyzed to acyclovir in the liver & intestines, so same mechanism of action as acyclovir ∙*Penciclovir* →guanosine analog that is phosphorylated by viral thymidine kinase →Inhibits viral DNA polymerase, but does not cause chain termination →Available for topical use ∙*Famciclovir* →deacetylated & oxidized to penciclovir ∙*Trifluridine* →phosphorylated by host cell enzymes →Affects host DNA polymerase as well as viral →Not used systemically because cannot differentiate between an infected and non infected cell ∙*Ganciclovir* →guanosine analogue →Active against CMV because CMV produces kinase called UL97 →→→UL97 can add a phosphate group to gancicyclovir (active in infected cell and not in uninfected cell) ∙*Vanganciclovir* →hydrolyzed to ganciclovir by intestinal and hepatic esterases →*Mechanism of Action:* →→→Phosphorylated by a protein kinase phosphotransferase (UL97) encoded by CMV →→→Competitively inhibits incorporation of dGTP into DNA (termination of chain elongation) →→→Inhibits viral DNA polymerase preferentially over cellular DNA polymerase (has activity against other herpesviruses like HSV, VZV, EBV, HHV-6, and HHV-8) →*Resistance to ganciclovir* →→→Point mutations in UL97 gene leads to inability to phosphorylate the drug →→→Mutation in the CMV DNA polymerase results in less affinity for ganciclovir triphosphate ∙*Cidofovir* →A cytidine analogue →Has 1 phosphate already and the 2nd and 3rd will be added by cellular enzymes →Will be active in infected and non-infected cell, but can be used because has a higher affinity for viral DNA polymerase →Competes with dCTP for incorporation into DNA →In vitro activity: CMV, HSV-1, HSV-2, VZV, EBV, HHV-6, HHV-8, adenovirus, HPV →Used for CMV retinitis (experimentally for adenovirus infection) →Resistance due to mutations in the viral DNA polymerase →→→If it is an Acyclovir-resistant HSV with thymidine kinase, will still be susceptible to Cidofovir ∙*Foscarnet* →A pyrophosphate analogue →Prevents cleavage of pyrophosphate from dNTPs, stopping DNA synthesis →Binds to herpesvirus DNA polymerase and HIV reverse transcriptase →Has a higher affinity for viral polymerase than cellular polymerase so that is why it works →Ganciclovir & cidofovir-resistant isolates of CMV are normally still susceptible to foscarnet

Mobiluncus

Appears gram (-) or gram variable rods w/ tapered ends Classified as gram (+) ∙Lack endotoxin ∙Have a gram (+) cell wall ∙Susceptible to gram (+) antibiotics M. curtisii abundant in women w/ bacterial vaginosis ∙Role is unclear

Contraindications of aspirin

Aspirin hypersensitivity Chronic liver disease Gout ∙Aspirin will have negative interaction w/ other meds used in treating gout Peptic ulcer Hemophilia, vitamin K deficiency → basically any clotting deficiency Diabetes ∙Not in regards to occasional aspirin use, this is in regards to regular use Chickenpox or influenza in children ∙*Can cause Reyes syndrome → causes irreversible mental retardation ∙Most pediatricins tend to steer you away from aspirin in children across the board*

Contraindications of most NSAIDs

Aspirin hypersensitivity ∙Highly likely they also have hypersensitivity to other NSAIDs Liver dysfunction Renal dysfunction Alcoholism, smoking (factors contributing to ulcers) Caution during pregnancy or during breast feeding ∙Ranked on scale of 1-4 on safety/harm for these pts

Contraindications of Diflunisal

Asthma

Types of tissue grafts

Autograft = tissue graft from one individual transplanted to another site in the same individual ∙Will always be a complete match b/c it is genetically identical material Isograft = a graft of tissues from one individual to a genetically identical individual of the same species ∙Need an identical twin Allograft = a graft of tissue from one individual to a genetically different individual of the same species ∙Majority of grafts Xenograft = graft of tissue from one individual to an individual of another species The only time you don't need to immunosuppress a transplant receipt is when they have received transplant from identical twin

Sarcoidosis

Autoimmune problem that involves lungs May find ring shaped granulomas ∙Middle area has macrophages and epithiolioid cells ∙Lots of tissue destruction ∙Some of the granulomas look as though they are merging together b/c there is so much damage

EBV infections in AIDS

B cell lymphoma Hairy oral leukoplakia ∙Productive infection of epithelial cells and the result is raised, white lesions on the tongue ∙Due to EBV, but just a productive infection

B cell antigen recognition

B cells see 'native' antigen ∙Linear or conformational Recognized by surface Ig ∙Induces intracellular signaling events

Anthrax

Bacillus anthracis would be a harmless, soil dwelling bacterium were it not for two extra DNA molecules set apart from its main chromosome Spores can remain viable in nature for up to 60 years, lend themselves to aerosolization Incubation period is 2 days - 8 weeks Virulence factors: protective antigen, edema factor, lethal factor and capsule ∙Lethal factor causes release of TNF-α and IL-1β Cutaneous anthrax (malignant pustule) ∙Starts as painless pruritic papule ∙Initial lesion appears inflamed, hot and typically has circling vesicles or blisters →Lesion is not suppurative ∙Later it ulcerates to be a round area w/ heaped border (size of quarter) and a blackened floor ∙Pt is febrile, feels groggy ∙Brawny edema is out of proportion to size of lesion ∙Eschar = cigarette burn like lesion, which is painless, depressed, small ulcer w/ crusted necrotic center and is surrounded by an erythematous halo ∙Biopsy - full thickness punch biopsy from the area adjacent to eschar can be used to make diagnosis GI anthrax is characterized by abdominal pain, rebound tenderness, hematemesis and bloody diarrhea ∙Occurs from ingestion of large number of vegetative forms in insufficiently cooked meat from infected animals Inhalational anthrax ∙Spores are transferred to lungs and then to mediastinal lymph nodes via lymphatics, where they turn into vegetative cells and release their deadly cargo ∙Biphasic illness →Initial phase - fever, malaise, chest discomfort (tightness), dry cough, HA, vomiting, chills, abdominal pain, fatigue →Fulminant phase - characterized by sudden fever, hemorrhage, pleural effusion, edema, dyspnea, diaphoresis, cyanosis, stridor, vomiting, necrosis, hypoxia and septic shock →→→*Mediastinal widening in a previously healthy pt due to massive lymphadenopathy w/ evidence of overwhelming 'flu-like illness' is essentially pathognomic of advanced inhalational anthrax Complications ∙50% develop hemorrhagic meningitis (cardinal's cap), thoracic hemorrhagic necrotizing lymphadenitis and hemorrhagic necrotizing mediastinitis ∙hemorrhagic meningitis presents as delirium, obtundation, cyanosis and hypotension Death due to O2 depletion, secondary shock, increased vascular permeability, respiratory and cardiac failure Dx ∙Culture shows square ended aerobic gram (+) rods w/ centrally located spores →Grow readily w/ nonhemolytic 'curled hair' colony morphology ∙Additional tests include serology, PCR, fluorescent antibodies for capsule and immunohistochemistry ∙Quick ELISA test Rx ∙Cipro 400mg IV every 8-12 hrs in contained setting or 500mg BID orally for 60 days in mass casualty situation ∙Alternatively, doxy 100mg BID can be used ∙Amoxicillin can be used in children ∙Penicillin G can be used after susceptibility testing results are available ∙Additional option is to extend antibiotic coverage to 100 days and add clindamycin or rifampin or vanco

Anaerobic Infections

Bacteria associated w/ disease are predominantly anaerobic Usually polymicrobial, involving aerobic, facultative and anaerobic organisms Strongly favored by trauma, immune-compromise, vascular insufficiency, diabetes Favorable conditions: lack of blood supply and/or presence of microbes which utilize O2

Proliferation & Production vs. Apoptosis & Destruction

Balancing act Tissue must be destroyed to re-establish normal functional tissue 3 ways to do this: ∙Phagocytosis ∙MMPs ∙Apoptosis Important destructive phases ∙Remove tissue destroyed in wound, invading BacT ∙Remove interim tissue to make way for blood vessels and normal epithelial tissue and ECM

Bartonellosis

Bartonella are fastidious pleomorphic aerobic gram (-) bacilli Children w/ young cats, HIV pts w/ low CD4 counts and lice-infested homeless people have increased risk B. bacilliformis, B. elizabethae, B. henselae and B. quintana are human pathogens Cat-Scratch Disease ∙Mainly in children ∙Cat flea is vector for B. henselae - inoculation papule near site of scratch/bite/lick ∙Characterized by tender lymphadenitis, developing two weeks after being scratched or bitten by carrier cat, often following flu-like symptoms ∙In immunocompetent hosts, infectious response is granulomatous and suppurative ∙Infection provides lifelong immunity ∙Paurinauds oculoglandular syndrome = marked by unilateral conjunctivitis, and a tender ipsilateral periauricular lymph node involvement ∙Dx: Warthin-Starry silver stain or Steiner stain ∙Rx: macrolides Bacillary Angiomatosis (epithelioid angiomatosis) ∙Causes vascular proliferative lesions of skin and other organs ∙Usually seen in immunosuppressed pts ∙Cutaneous manifestation is an erythematous papule about 1cm in diameter w/ surrounding collar of scale →Dermal form = red papule →Subcutaneous nodule = painful ∙B. quintana most commonly presents as subcutaneous nodules ∙Many pts present w/ weight loss, fever, abdominal pain, hepatosplenomegaly, and raise alkaline phosphatase →Causes relapsing fever and limb pain →Can cause osteomyelitis, pulmonary dz, splenic involvement, and aseptic meningitis ∙Oroya fever (Carrion's disease) - term used after fatal experiment of self-inoculation of agent from cutaneous lesion →B Bacilliformis causes acute hemolytic anemia →Fleas important vectors →Bacteria causing massive hemolytic anemia, fever, muscle pain, delirium and coma ∙Bacteremia and endocarditis seen in homeless and alcoholics →Characterized by culture-negative endocarditis ∙Transmission occurs through bite of human body louse →Seen in homeless population ∙Rx = 8 wk course of macrolides

Arachidonic acid cascade

Basic mechanism of all NSAIDs is to inhibit COX ∙COX-1 is in all tissues and is constitutively active ∙COX-2 is in inducible one that springs into action in tissues that have inflammation ∙Inhibits production of thromboxanes and prostaglandins

Angiogenesis sustains tumor growth

Because it is vital to new tissue formation, angiogenesis is a fundamental requirement for the development and differentiation of new organs during embryogenesis ∙In adults, the need for angiogenesis is generally limited to wound healing and reproductive function (eg, the menstrual cycle) In tumor cells, however, the process of angiogenesis is critical for sustaining tumor growth beyond approximately 2 mm in size ∙Thus, upregulation of angiogenesis is a key step in sustained tumor growth and may also be critical for tumor metastasis The image shown here, is the original depiction of how angiogenesis affects tumor growth ∙When the tumor is small, it obtains nutrients and oxygen by diffusion ∙The tumor then induces neovascularization, at which point it can grow larger and spread

Amphotericin B

Binds to ergosterol, producing ion-channels Membrane becomes leaky, resulting in cell death Oxidation of amphotericin B generates toxic free radicals Amphotericin B also binds cholesterol, but with a lower affinity ∙*b/c it can bind cholesterol, you can get side effects* Toxicity problems ∙Renal impairment ∙Loss of potassium & magnesium ∙Infusion reaction (fever, chills, tachypnea) ∙Abnormal liver function tests (occasionally) Lipid formulations are less toxic ∙Higher doses can be used Broad spectrum antifungal; used for systemic infections Resistance mechanisms ∙Decrease in the amount of ergosterol in the fungal cell wall ∙Reduced ergosterol affinity for the drug

Considerations for antiviral therapy

Block a virus-specific activity... ∙Targets include enzymes and attachment proteins ∙Steps in the replication cycle that are unique to viruses Do the above without interfering with a host cell function ∙Disrupting host cell functions leads to toxicity Current antivirals inhibit actively replicating virus, not latent infections ∙Nothing to target with a drug in a latent infection For acute viral infections, you mostly just treat the symptoms (example: with a cold, you wouldn't take an antiviral, you would just take medicines to make you feel better) Early initiation of therapy ∙Viral replication may precede the symptoms, so it's difficult to catch Chemoprophylaxis vs. treatment ∙Treat outbreaks in confined setting →Example - flu outbreak in a nursing home →You want to prevent the spread of the disease so you administer the antiviral until the person can make their own antibodies →In genital herpes you can administer an antiviral to prevent recurring outbreaks Useful for more chronic infections HIV, viral hepatitis

Vasculogenesis

Blood vessels assembled during embryonic development A primitive vascular network Established from endothelial cell precursors called angioblasts

Angiogenesis

Blood vessels provide growing organs w/ needed oxygen and promote organ morphogenesis Blood vessels derive from endothelial precursors which share an origin w/ hematopoietic precursors ∙This link is important for angiogenesis Progenitors produce a primitive group of vessels, which develop into capillaries Vessels in these capillaries develop into arteries and veins Eventually this plexus expands and organizes into a vascular network of large and small blood vessels Arteries: endothelial cell channels become covered by pericytes and smooth muscle cells, providing strength and regulation of vessel perfusion Blood vessel formation in adults can be due to branching and extension of adjacent blood vessels ∙Can also occur by recruitment of endothelial cells from bone marrow *Critical to chronic inflammation, fibrosis, tumor growth and vascularization of ischemic tissue*

Killed bacterial vaccines

Bordetella pertussis ∙When given with tetanus toxoid and diptheria toxoid (DTP), the presence of the Bordetella organism causes stronger immune responses to the toxoids →Bad reactions ∙Now using an "acellular" Bordetella preparation is used →Toxoid →Filamenous hemaggutinin, pertactin, fimbrial antigen

How antigen gets to secondary lymphoid tissue

Both dendritic cells and macrophages act as sentinels for infection in tissue ∙Upon infection, both cells uptake pathogens and process and present antigen Differences b/w these cells: ∙FUNCTION →macrophages have a range of function in defense and repair of damaged tissues →*dendritic cells only known function is to trigger T cell responses* ∙MOBILITY →dendritic cells are migratory and can carry their antigen load from site of infection to nearest secondary lymphoid tissue - this is b/c activation induces expression of CCR7, the receptor for chemokine CCL21 →macrophages, in contrast, are resident in tissues and do not migrate →→→however, macrophages resident in lymphoid tissue can process and present antigen that is carried passively in lymph from infected tissue

Immunocytochemistry of CP Persistently Infected THP-1 Monocytes

Brown areas indicate labeling for chlamydia organism Chlamydia often becomes persistent, even in monocyte ∙Lysosome don't bind

EBV-associated cancers

Burkett's Lymphoma ∙Monoclonal B cell lymphoma of jaw and face ∙Most common in children/young adults in Africa (malaria's role in impairing cellular immunity could be involved because it allows the virus to replicate) ∙EBNA-1 and EBV DNA associated with tumors ∙Tumor cells contain chromosomal translocations because they place the C-myc oncogene next to active promoter, so it starts to become expressed X-linked lymphoproliferative disease (don't have T cells to clear B cells) ∙Duncan disease: recessive male disorder ∙Mutation prevents B and T cells from interacting ∙Polyclonal leukemia-like B cell proliferative disease B cell lymphomas in people lacking T cells (AIDS) ∙Polyclonal B cell activation is not controlled by T cells ∙Leukemia-like B proliferative disease and lymphomas ∙Transplant recipients are at risk for post transplant lymphoproliferative disease ∙Could be the result of virus exposure or reactivation Hodgkin lymphoma (HL) ∙Lymphoid neoplasm of B cell origin ∙Reed-Sternberg cells: neoplastic cells in tumor (out of 5 subtypes of HL, 3 are associated with these cells) ∙EBV though be responsible for subset of HL patients Nasopharyngeal carcinoma: epithelial cell carcinoma ∙EBV DNA is associated with cancer cells ∙Endemic in Asia and mainly adult males

Obligate Intracellular Bacteria Family Chlamydiaceae

C. trachomatis - causes a wide range of clinical diseases - trachoma, urogenital infections (STD), and Reiter's syndrome ∙Sexual transmission: most frequent bacterial STD pathogen in US →Can be transmitted by passage to newborn at birth, breaks in skin or mucous membranes →Frequently occurs w/ gonorrhea as well ∙Trachoma spread to eye by hand, droplets, clothing, flies ∙Typically can be treated w/ antibiotics →Usually will treat →May remain asymptomatic but not clear organism, creating persistent problems ∙Virulence factors: intracellular replication in vacuoles - prevention of phagolysosomal fusion, survival of EBs resulting from cross-linking of membrane proteins →Pathology is a result of re-infection and host response ∙Symptoms: →Urogenital - cervicitis, endometritis, urethritis - mucopurulent discharge →trachoma - follicular conjunctivitis with diffuse inflammation →Reiter's syndrome - urethritis, conjunctivitis, polyarthritis, mucocutaneous lesions Chlamydia pneumoniae - bronchitis, pneumonia, sinusitis, and potentially, atherosclerosis, Alzheimer's disease, & multiple sclerosis ∙Transmitted: human to human by respiratory secretions ∙Virulence: same as for trachomatis, will destroy epithelial cells, and infect endos, sm muscle, and macrophages ∙Symptoms: often asymptomatic, persistent cough, malaise →Can get resolution of symptoms but we don't know if we get clearance of organism Chlamydia psittaci - psittacosis (parrot fever) - severe pneumonia ∙This pneumonia is often fatal in human population ∙Transmission: respiratory tract from infected birds ∙Virulence: replication in vacuoles, prevention of phagolysosomal fusion ∙Symptoms: →Pulmonary: non-productive cough, rales, consolidation →CNS: headache, encephalitis, convulsions, coma

Side effects of aspirin

CNS: tinnitus, vertigo, confusion, delirium GI: nausea, vomiting, local gastric irritation w/ bleeding ∙Most common ∙*GI irritation is caused by decreasing inflammation via decreased prostaglandins, decreasing protective effects in stomach* ∙Bleeding also makes sense b/c of anti-thrombogenic effects Hepatotoxicity w/ prolonged high doses, viral infection