OEQ/MCQ Concepts

1. prediction addresses whether a test can accurately predict the concurrent presence (or future occurrence) of an outcome—in this case a severe, infection. Assessment of how tests perform compared to other existing tests is an outcome of prediction. 2. Causation is establishing a causal relationship among biologic, behavioral, etc. factors. 3/4. Mediation and interaction are closely related to causation (mechanisms and relationships, respectively, of causation) 5. Description addresses the frequency (e.g., incidence) of risk factors, diseases, and conditions. 6. Attribution addresses what fraction or how many cases of disease Y can be eliminated if a causal exposure X is eliminated or reduced?

"Big 6" objectives of epidemiologic/clinical research studies

macrophages and neutrophils

innate immune system cells

This type of brain lesion is an acute red hemorrhagic infarct of the brain. This lesion would be acute because the patient developed sudden, serious symptoms. The lesion appears to be wedge like, discolored, and due to pooling of the bloood in the area. Typically we see red hemorrhagic infarcts in areas of dual blood supply. Here, because the brain is not an area of dual blood supply it must be due to an occlusion and previous injury to the vessels in the area. In this area we should see necrosis of the brain which is due to castrotrophic cell death.Specifically, cells in the infarcted area would show increased cytoplasmic eosinophilia (redness), which is due to the loss of cytoplasmic RNA and denaturation of cytoplasmic proteins. In addition, necrotic cells would show nuclear changes such as fading, shrinkage, and/or fragmentation. Because leak of cytoplasmic contents from necrotic cells acts as an inflammatory stimulus, some acute inflammatory infiltrate would likely also be present.

65-year-old woman (she/her) who is a retired teacher is brought to the Emergency Department (ED) 24 h after suddenly developing right-sided weakness and a loss of sensation on the right side of her body. Based on the imaging performed in the ED, she is diagnosed with a lesion similar to the one showed in the image below and is admitted to the hospital for supportive care. Her granddaughter (she/her), a college biology major who will start medical school next year, asks you to explain what happened to her grandmother. Because the granddaughter is eager to learn as much about medicine as possible, your answer is quite thorough and includes (1) the name of the brain lesion; (2) an explanation for how its gross appearance reflects the underlying disease mechanisms; and (3) a general description of cellular changes that would be seen under the microscope in the affected part of the brain. (The model answer is 3 brief paragraphs in length.)

Carcinoma tells us that the tumor is of epithelial origin rather than mesenchymal (sarcoma). "squamous cell" indicates that the origin is the squamous epithelium which can be found in the epidermis region of the skin. Therefore, the tumor most likely originated from the skin.

A 55-year-old woman (she/her) presents with an ulcerated, irregular, and painful 2-cm mass eroding into the skin of her lower left leg. She has no significant contributory medical history. A biopsy of this mass results in a pathologic diagnosis of squamous cell carcinoma. Based on the diagnosis "squamous cell carcinoma," discuss the likely cell and organ origin of this neoplasm.

Posterior - medial aspect of the distal left hand Recall that in anatomy, all references to the position of structures are given with respect to the "anatomical position." This position refers to a subject facing forward with feet together, arms resting by her/his sides, palms forward, and eyes looking directly toward the horizon.*****

A family medicine physician sees a patient in urgent care who presents with a laceration on his hand pictured below. Which of the following most correctly describes the location of this laceration on his left 5th digit that she will document in the patient's chart?

TI = TD 50/Ed 50 = 1 microgram/kg over 50 nanogram /kg (1 x 10^ -6)/(50 x 10^ -9)= 20

A pharmaceutical company is assessing the safety of a new drug, named "lowem", to treat motion sickness. The toxic response to "lowem" is headache, while the desired response is defined as reduction in nausea upon sitting in a moving car. The study includes 300 volunteers and yields the following data. TD50 = 1 microgram /kg and ED50 = 50 nanogram/kg. What is the therapeutic index of this drug? Select one: a. 0.02 b. 1 c. 20 d. 50

No I do not expect that bone development will be affected to the same extent as bone formation, because bone formation does not start with a blood clot. Since we are given that NSAIDS affects formation of blood clots, it follows that repair is affected but new formation is not. Additional background info: (meaning if this were an exam question the first paragraph would be enough to meet expectations but here we add more for your leanring). Bone repair closely resembles bone development. During bone repair, the tissue goes through the following steps: 1 Formation of a blood clot 2 Recruitment of mesenchymal stem cells 3 Differentiation of cartilage, followed by hypertrophy 4 Apoptosis of hypertrophic chondrocytes 5 Degradation of cartilage matrix by osteoclasts 6 Angiogenesis 7 Recruitment and differentiation of osteoblasts 8 Synthesis of bone 9 Remodeling of bone During endochondral boneformation, there is no formation of a blood clot but otherwise the process (steps 2-9) occurs in much the same way.

A 53-year-old construction worker comes to the emergency room after falling from the roof of a new housing development and landing on their back three days prior. The patient notes severe pain in their lower back, an intense headache and a high fever. Upon examination, the patient's sacrum and coccyx were fractured due to the impact. The orthopedic surgical team has determined that the patient will require a spinal fusion procedure to correct the multiple vertebral fractures. The patient requires surgery and is asked if they want to enroll in a clinical trial. UCSF is participating in a clinical trial studying the effect of ibuprofen, a non-steroidal anti-inflammatory drug (NSAID) for pain control on bone recovery after surgical repair. The abstract is given below..... RESULTS: Ninety-eight patients were enrolled into this study, 68 completed the follow-up and had the 6-month computed tomographic scan, and there was a 63% compliance rate with the treatment regimen. The incidence of radiographic nonunion was 19% for group 1, 35% for group 2, 24% for group 3, and 62% for group 4 (P = 0.012). Pain visual analog scores (VASs) were significantly higher for patients with radiographic nonunion (VAS 4 vs. VAS 1, P = 0.002). CONCLUSIONS: Treatment with 6 weeks of NSAID appears to increase the incidence of nonunion. From the above you can see that NSAIDS can affect bone repair. One of the effects of certain NSAIDs is a reduced ability to form a blot clot. Based on this knowledge would you expect that new bone development be affected by NSAIDS to the same extent as bone repair? Why or why not? In your answer include the stages/steps of bone repair and compare these to the stages of endochondral bone formation.

To efficiently find relevant papers on this topic, one could use PubMed database of the National Library of Medicine. Potential search terms could be: ankle fracture AND fracture healing AND (time factors OR accelerate OR acceleration OR promote OR promotion). Alternative acceptable search words include bone, growth or healing. Better results could be obtained by using Medical Subject Headings (MeSH) terms, e.g., ((ankle injury[MeSH Terms]) AND (fracture healing[MeSH Terms])) AND (acceleration[MeSH Terms]).

A 53-year-old construction worker comes to the emergency room after falling from the roof of a new housing development and landing on their back three days prior. The patients notes severe pain in their lower back, an intense headache and a high fever. Upon examination, the patient's sacrum and coccyx were fractured due to the impact. The orthopedic surgical team has determined that the patient will require a spinal fusion procedure to correct the multiple vertebral fractures. The medical student (she/her) on the team is curious whether there is anything that can be done to speed the bone healing process. She finds that a quick Google search for 'accelerate bone healing' produces 207,000 hits. She decides to do a more refined search to determine if there is any data to support methods to accelerate bone healing. What search engine do you recommend she use? What search terms should she use? In your answer please walk through the steps you would take to do this search.

The type of study design is an experimental randomized control trial. This is a randomized controlled double-blind trial: "randomized" because of random group assignments, "controlled" because there is a control group (placebo). A randomly assigned and given either the drug of placebo and the outcome will be evaluated by the researchers. This would be experimental rather than observational because the patients are given an intervention/drug (cemipliamb).

A 55-year-old woman (she/her) presents with an ulcerated, irregular, and painful 2-cm mass eroding into the skin of her left lower leg. She has no significant contributory medical history. A biopsy of this mass results in a pathologic diagnosis of squamous cell carcinoma. Additional workup confirms lymph node involvement by squamous cell carcinoma. You and the attending pathologist review the biopsy of the patient's skin tumor; you notice that the skin tumor is highly cellular, mitotically active, and shows many poorly differentiated cells. The patient's partner searches the internet and finds a clinical trial is offered at UCSF for patients with advanced squamous cell carcinoma. Study title: Study of Adjuvant Cemiplimab Versus Placebo After Surgery and Radiation Therapy in Patients With High Risk Cutaneous Squamous Cell Carcinoma Eligibility: Patients 18 and up with metastatic cutaneous squamous cell carcinoma Study description: After local control therapy with surgery and radiation, patients will be randomly assigned to receive cemiplimab or placebo. The Participant, Care Provider, Investigator, Outcomes Assessor will not know which therapy the patient receives. Study objectives: The primary objective of the study is to compare disease-free survival (DFS) of patients with high-risk cutaneous squamous cell carcinoma (CSCC) treated with adjuvant cemiplimab, versus those treated with placebo, after surgery and radiation therapy (RT). The secondary objectives of the study are: - To compare the overall survival (OS) of high-risk CSCC patients treated with adjuvant cemiplimab, versus those treated with placebo, after surgery and RT - To compare the effect of adjuvant cemiplimab with that of placebo on patients' freedom from locoregional recurrence (FFLRR) after surgery and RT. What type of study design is this? Explain your reasoning.

The presence of lymph node involvement suggests the tumor has spread/metastisized. Metastisis, mitotic figures/abnormalities, poorly differentiated cells are a characteristic of an agressive, high grade tumor. In addition, high grade tumors are classified with infultration of cells that are different from the surrounding tissue they infultrate and resemble the original tumor cells. A low grade tumor typically has cells that resemble the tissue of origin.

A 55-year-old woman (she/her) presents with an ulcerated, irregular, and painful 2-cm mass eroding into the skin of her left lower leg. She has no significant contributory medical history. A biopsy of this mass results in a pathologic diagnosis of squamous cell carcinoma. Additional workup confirms lymph node involvement by squamous cell carcinoma. You and the attending pathologist review the biopsy of the patient's skin tumor; you notice that the skin tumor is highly cellular, mitotically active, and shows many poorly differentiated cells. How are these findings related to the presence of lymph node involvement by the tumor?

c. Between L4-L5 vertebrae, because this is inferior to the spinal cord

A patient is suspected of having bacterial meningitis and is scheduled to have a lumbar puncture to remove cerebrospinal fluid and test it for the presence of bacteria. Which is the safest location for the lumbar puncture and why? a. Between C1-C2 vertebrae, because there is no intervertebral disk here. b. Between T12-L1 vertebrae, because this is an easy landmark to locate. c. Between L4-L5 vertebrae, because this is inferior to the spinal cord d. Between S2-S3 sacral segments, because this is the level of the cauda equina

The anterolateral tibial tubercle (Gerdy's tubercle) on the proximal aspect of the tibia is the attachment site of the iliotibial band/tract. The iliotibial band/tract is a dense thickening of the fascia lata, and is the aponeurosis for the tensor fasciae latae and gluteus maximus muscles. Repetitive motion (such as from running) may cause local inflammation at the distal aspect of the iliotibial band, often a result of tightness of the band, poor body mechanics, or muscle weakness

A patient presents with knee pain that prevented her from running. You ask where her pain is. "It is on the outside of the knee," and she points to the lateral knee just below the joint line. Palpation at the proximal anterolateral tibia elicits pain. The MOST likely cause of her knee pain is:

b.The clearance would be decreased and the half life would be increased If we remove a kidney the body will be less effective at clearing the drug, and the clearance will be reduced. As a consequence, if we remove the drug less fast, it will remain in the body longer, which you will see as increased half-life. The relationship is mathematically described as follows: t1/2= 0.693 * Vd/CL

After her scooter accident, BL was lucky enough not to develop full-blown rhabdomyolysis, which can severely damage the kidneys. If she had developed kidney damage, what consequences would that have for drugs that are renally eliminated? Select one: a.The clearance would be decreased and the half life would be decreased b.The clearance would be decreased and the half life would be increased c.The clearance would be increased and the half life would be decreased d.The clearance would be increased and the half life would be increased

No we do not expect smooth muscle to be paralyzed by nicotine as smooth muscle does not have NM receptors (rather smooth muscle has M, alpha and beta receptors).

An 8-month-old child swallowed two cigarette butts while in the care of a sitter. When the mother arrived home, the child was drowsy and limp, so she called 911. On arrival at the hospital, the child was very drowsy, and breathing slowly and with difficulty. A breathing tube was placed and attached to a ventilator. On examination, the child was found to have constricted pupils (miosis), high blood pressure, and diarrhea. The nicotine had also caused the child to produce excess secretions, which were making it hard to get oxygen into the blood in the lungs. Medication was administered to dry the secretions. The child was admitted to the pediatric intensive care unit where they remained minimally responsive for the rest of the night. The next day, the child could breathe on their own. After three days in the hospital, the symptoms resolved and the child was discharged. As the case above demonstrates, smooth and skeletal muscles differ in several ways, which are crucial for understanding their physiological functions and the pharmacologic effects on each. Do you expect the smooth muscle also to be paralyzed by nicotine? Why or why not?

Osteoclasts are the primary cell type responsible for bone resorbtion. Chondroblasts are immature chondrocytes, which produce cartlidge; osteoblasts are immature osteocytes; osteocytes produce bone (not resorb it).

Bone remodeling will take place at the fracture site of TC's pelvis; bone is resorbed by: Select one: a. Chondroblasts b. Osteoblasts c. Osteoclasts d. Osteocytes

Signs that result from SANS activation: hypertension Signs that result from PANS activation: excess mucus secretions, miosis, diarrhea We see both SANS & PANS effect because the ganglia in both arms of the ANS contain NNreceptors that can be activated by nicotine. Nicotine directly activates these NNreceptors, leading to excess firing of both PANS and SANS postganglionic neurons. Most tissues are dually innervated, in which PANS and SANS activation leads to opposing effects. In these tissues, the arm with the greater tone at baseline will"win out" and cause a toxic response. In the blood vessels, SANS tone dominates, so the patient experiences hypertension. In most other systems, including the digestive system, PANS tone dominates, so the patient experiences diarrhea and miosis. It is important to note, however, that the effects of nicotine are very complex; there are also nicotinic receptors located in the central nervous system, which can override the classic SANS/PANS effects. Clinically, it is difficult to predict the specific effects a patient overdosing on nicotine will exhibit.

An 8-month-old child swallowed two cigarette butts while in the care of a sitter. When the mother arrived home, the child was drowsy and limp, so she called 911. On arrival at the hospital, the child was very drowsy, and breathing slowly and with difficulty. A breathing tube was placed and attached to a ventilator. On examination, the child was found to have constricted pupils (miosis), high blood pressure, and diarrhea. The nicotine had also caused the child to produce excess secretions, which were making it hard to get oxygen into the blood in the lungs. Medication was administered to dry the secretions. The child was admitted to the pediatric intensive care unit where they remained minimally responsive for the rest of the night. The next day, the child could breathe on their own. After three days in the hospital, the symptoms resolved and the child was discharged. In this case, some of the signs and symptoms indicate excess SANS activation, while others indicate excess PANS activation. Explain this response; include the receptors involved and a description of the physical manifestations of both autonomic divisions seen in this case.

The drug administered was likely atropine, a muscarinic antagonist. This medication would directly block signaling at M receptors on PANS-innervated cells, including those involved in secretion (e.g. glands in the GI tract). (Recall from the question above that PANS-innervated tissues are stimulated through effects of nicotine signaling at the ganglia, through activation of postganglionic N receptors. As a muscarinic antagonist, atropine basically blocks the downstream effects of PANS activation at the tissue level.) We would expect to see GI side effects related to antagonism of M receptors on GI smooth muscle. PANS activation of the digestive tract via M receptors causes smooth muscle contraction, which increases gut motility. Atropine will block these M receptors, leading to decreased smooth muscle contraction, causing decreased gut motility (constipation). Ligands that act through M receptors normally mediate smooth muscle constriction by activating Gq. Gq leads to calcium release from the sarcoplasmic reticulum, which leads to contraction. By blocking activation of the M receptor, downstream calcium release is decreased.

An 8-month-old child swallowed two cigarette butts while in the care of a sitter. When the mother arrived home, the child was drowsy and limp, so she called 911. On arrival at the hospital, the child was very drowsy, and breathing slowly and with difficulty. A breathing tube was placed and attached to a ventilator. On examination, the child was found to have constricted pupils (miosis), high blood pressure, and diarrhea. The nicotine had also caused the child to produce excess secretions, which were making it hard to get oxygen into the blood in the lungs. Medication was administered to dry the secretions. The child was admitted to the pediatric intensive care unit where they remained minimally responsive for the rest of the night. The next day, the child could breathe on their own. After three days in the hospital, the symptoms resolved and the child was discharged. What medication do you think was administered to dry the child's secretions? In addition to its therapeutic effect, what gastrointestinal side effects might you see in a patient taking this drug? In your answer, name the receptors and address the molecular signaling events in smooth muscle that are impacted by the presence of this drug.

: The spinal cord terminates typically at the L1-L2 vertebral level as the conus medullaris in an adult. Below L2, the nerve roots continue inferiorly as a group collectively referred to as the cauda equina. The ideal location for a lumbar puncture on an adult is the L4-L5 vertebral level as the spinal cord has terminated and thus will not be injured. In addition, the vertebral canal is easily accessible by a needle within the lumbar vertebral column (compared to the sacrum). In a lumbar puncture the needle would pass from superficial to deep through skin, subcutaneous tissue, supraspinous ligament, interspinous ligament, ligamentum flavum, dura mater, arachnoid mater

At what vertebral level is it considered safe for their doctor to perform a lumbar puncture and why? Describe the different layers (superficial to deep) that the spinal needle will pass through to reach the cerebrospinal fluid (CSF).

The radiograph indicates a mid-shaft fracture of the right humerus. The nerve that is directly associated with this portion of the humerus is the radial nerve. At this location the radial nerve has innervated the majority of the triceps brachii, so there may be minor weakness in elbow extension. The major motor deficit will be evident at the wrist and digits. The radial nerve innervates the entire posterior compartment of the forearm. This means the patient would have a complete inability to extend the wrist and extend digits 1-5 at the MCP joints, and severe weakness in extending digits 1-5 at the PIP and DIP joints (lumbricals are still functioning). The patient would also have some weakness (though not a complete deficit) in supination of the forearm (supinator) and abduction of the thumb (abductor pollicis longus). The posterior cutaneous nerve of the forearm comes off the radial nerve proximal to the fracture, so they would still likely have sensation on the posterior portion of their forearm. The sensory deficits would be noticeable on the posterior surface of the hand over the anatomical snuffbox, the 1st dorsal interosseous and over the dorsal surface of the thumb.

Based on the radiograph, describe the location of the fracture (bone and region) and predict which nerve is most likely damaged due to close proximity to this region of bone. Once you have identified the nerve that is damaged, explain the motor and sensory deficits that the patient will present with.

There was no difference in the proportion of infection between the two groups of patients. However, patients receiving hydroxychloroquine had a much higher frequency of side effects compared to the placebo group. Based on these data, I believe that hydroxychloroquine may cause you more discomfort but not decrease your risk of getting Covid-19. One thing that is important to consider is the external validity of the study, i.e., whether patients from the NEJM are similar to you and whether study findings can be applied to youThe age range of the patients in the study was 32-51 years old, so researchers didn't evaluate the impact on patients in your age group (>70 years old). Nonetheless, based on the lack of results and the increased side effects for this medicine, I do not believe it would be beneficial to you.

Based on these data, what would you recommend to the patient? Include a comment on the external validity of the study as it relates to your patient.

Both a high-ankle sprain and a low-ankle sprain involve damage of varying degrees to ligaments that hold bones in the ankle complex together. A high-ankle sprain involves damage to the distal tibiofibular joint (joint between the distal ends of the tibia and fibula), while a low-ankle sprain involves damage to the ligaments holding the tibia/fibula to tarsal bones and can occur either on the medial side of the ankle (deltoid ligament) or the ligaments on the lateral side of the ankle (anterior talofibular, posterior talofibular, & calcaneofibular ligaments). Since this patient described rolling their ankle so that the outside (lateral side) of their ankle hit the ground, this indicates that the patient excessively inverted their foot and most likely either tore the anterior talofibular or the calcaneofibular ligaments as they are the most commonly torn ligaments in the ankle with excessive inversion. The lateral malleolus is likely the bony structure fractured as that is the "bony portion" of the ankle on the lateral side that is superficial compared to other bones at the ankle joint.

Compare and contrast a high-ankle sprain to a low-ankle sprain. What joints are involved in each sprain and what ligaments are likely damaged in each? What bony structure may be fractured based on the patient's description of the "bony portion on the outside (lateral side) of their ankle hitting the pavement hard during the ankle roll"?

a. Diarrhea Pyridostigmine is an acetylcholinesterase inhibitor. If ACh is not broken down there is more ACh signalling both in the gangia and at the organ level. If we have more ganglia signalling we see more of the dominant arm's effect. In most organs & tissues the Parasympathetic arm is dominant. Thus we expect to see Parasympathic effects ( rest & digest) salivation, sweating, bradycardia, urination and diarrhea. ( think DUMBBELSS!)

If a soldier were to accidentally take an overdose of pyridostigmine, the soldier would MOST likely experience drug-induced: Select one: a. Diarrhea b. Dry mouth c. Hyperthermia d. Tachycardia e. Urinary retention

Epinephrine Explanation: The receptors in the lungs that relax bronchiolar smooth muscle when activated are beta-2 receptors. Epinephrine is an agonist at alpha-1, alpha-2, beta-1 and beta2 receptors Ach and neostigmine (indirectly) activate N and M receptors. Bethanechol is a muscarinic agonist.

In a person with asthma who is experiencing bronchoconstriction and, as a result, difficulty obtaining enough oxygen, the BEST pharmacologic approach to reversing the bronchoconstriction would be the administration of: Select one: a. Acetylcholine b. Bethanechol c. Epinephrine d. Neostigmine

cellular swelling, nuclear pyknosis, enzymatically degraded cellular contents and disrupted plasma membrane integrity

Necrosis

d. 3 hours Ethanol undergoes zero order elimination. This means that the elimination rate is constant. She eliminated 25-15 or 10 mmol in 2 hours, as we assume the volume in her body (expressed in liters here) remains constant. Thus, she eliminates 10 mmol/2 hours, which is equal to 5 mmol/hour. The current Cp = 15 mmol/L, thus at a rate of 5 mmol/hour, it will take 3 hours to eliminate it all to a Cp of zero. Or to explain it in another way: in 2 hours she will eliminate 10 mmol ( just like the previous 2 hours) leaving 5 mmol behind. It will take half of 2 hours (one hour) to eliminate this. Total time to eliminate the ethanol to zero is 3 hours.

Patient BL (she/her) was intoxicated when she fell off her scooter. Her blood ethanol level was 25 mmol/L when she arrived at the hospital. It took 2 hours for her blood ethanol level to drop to 15 mmol/L. Assuming her volume is being kept constant by the Trauma team in the Emergency Department, how much longer will it take her blood ethanol level to reach zero, since the last measurement of 15 mmol/L? Select one: a. 0.5 hour b. 1 hour c. 2 hours d. 3 hours

Ethical principles that need to be considered are beneficence, non-maleficence and autonomy. Beneficence is acting in the patient's best interest. It would be in the patient's best interest to remain in the hospital due to his confusion and disorientation. It may furthermore cause him harm if he is unsafely left the hospital in a confused state (non-maleficence = to do no harm). The other ethical principle to consider is autonomy, where a person has a right to their own self-determination and over what they want to have done to their body.

Postoperatively, the patient still has high levels of morphine in his system, making him very sleepy, disoriented, and confused. Although he is very sick, at one point he tells his doctor, "I don't want any medicines, I want to leave the hospital." His doctor worries that if she does not treat the patient and he leaves the hospital, he could be in danger. Describe two conflicting core ethical principles that apply to this clinical scenario.

hemorrhagic (red) infarct, which theoretically can be a result of occlusion/embolus Typically, hemmoragic infarcs are common in areas of the body with dual blood supply, however, if there was a previous injury (in this case of the patient a previous heart attack), we can see hemmoragic infarcts.

Red hemorrhagic infarct

e. Prediction Of the Big 6, prediction addresses whether a test can accurately predict the concurrent presence (or future occurrence) of an outcome—in this case a severe, infection. Assessment of how tests perform compared to other existing tests is an outcome of prediction. Causation is incorrect as this addressed establishing a causal relationship among biologic, behavioral, etc. factors. This test does not have a causal relationship. Mediation and interaction are closely related to causation (mechanisms and relationships, respectively, of causation) and are thus not correct answers. Description addresses the frequency (e.g., incidence) of risk factors, diseases, and conditions.

Researchers wish to describe the test characteristics of a novel, point-of-care (POC; i.e., performed quickly at the bedside) laboratory assay to be used for the diagnosis of a severe, systemic infection. They compare the POC test performance to other existing laboratory assays. Which of the following "Big 6" objectives of epidemiologic/clinical research studies does this study primarily address? Select one: a. Causation b. Description c. Interaction d. Mediation e. Prediction

All intestinal epithelia have apical junctional complexes The lining of the colon is a simple columnar epithelium and thus is not squamous or stratified. Stratified squamous epithelia that provide protection against the external environment (like the skin and the palate in the mouth) are keratinized so they are more durable. This does not apply in the colon, which is not exposed to the external environment and, in any case, is neither stratified nor squamous. The cells that make up the lining of the colon do need to be tightly connected to each other through cell-cell junction complexes, such as apical junctions so that the cells stay together as a single sheet and to prevent food, bacteria, and other particulates from passing between the cells.

TC underwent surgery for colon repair. The colon is lined with specialized epithelium. All intestinal epithelia Select one: a.Are keratinized b.Are squamous c.Are stratified d.Have apical junctional complexes

X-rays use radiation to capture an image of tissues of the body based on different densities of tissues that the radiation passes through. Advantages: X-rays are fast, cheap and good for bony structures, but they expose the patient to radiation (disadvantage) . MRIs use magnets and adjustments can be made to visualize different tissues in the body, particularly soft tissue structures like ligaments (advantage) . MRIs provide high resolution imaging and do not expose patients to radiation (advantage) , but are slow and expensive (disadvantage).

The doctor decides to order an imaging test and is choosing between X ray and MRI both of which can be used to diagnose MSK injuries. Compare and contrast these two modalities by describing one advantage and one disadvantage for each test.

Antibiotic X has only been evaluated in preclinical studies where the drug is tested through in vitro systems and experimental animals. This drug cannot be given to the patient until it is FDA approved. To gain approval, the drug must be tested in the following types of trials: phase 1: test safety and kinetics in healthy people phase 2: test in small cohort of patients with the target disease phase 3: test in large multicenter trial to show safety and efficacy

The medical student on the team has read about a promising new antibiotic, Drug X, that has performed well in preclinical studies (in vitro experiments and animal models). The medical student wonders why we can't give this antibiotic to the patient right now while they are acutely ill. Explain why Drug X cannot be given to the patient now and what types of studies would have to be completed before Drug X could be given to patients.

The patients liver appears to be discolored, and enlarged. The patient is showing the cardinal signs of inflammation: fever, swelling, and pain as well as an increase of white blood cell count (leukyosis). The pain is a result of the edema compressing on the tissue and nerves in addition to prostaglandins which are inflammatory mediators. Fever is due to the release of inflammatory mediators and vasodilation. Swelling is a result of vascular leakage and tissue edema, resulting in exudate. The sudden onset of pain the patient is experiencing acute inflammation which involves the body's innate immune system such as the presence of neutrophils. The pathologic findings confirm the inflammation - we could also sample the blood and check for exudate, an increased plasma protein concentration linking to vascular leakage.

The next patient you encounter is a 22-year-old college student (she/her) who is undergoing emergency abdominal surgery. Prior to surgery, she was curled up in her hospital bed in significant pain that started last night. Her temperature was 39.4°C and her white blood cell count (WBC) 19,000 cells per microliter (upper limit of normal is 10,000 cells per microliter). The surgeon removed the patient's appendix, which is shown in the image below (with normal appendix for comparison on the right): Name the pathologic process affecting the patient's appendix and discuss how the pathologic findings connect to her clinical presentation.

There are two major routes of drug elimination: renal excretion (hydrophilic drugs) and hepatic metabolism (lipophilic compounds that undergo enzymatic conversion to inactive compounds that are then often excreted in the urine). Since this drug is hydrophilic, it is safe to expect that it will be eliminated via renal excretion. You may need to reduce the dose of the antibiotic if the patient has renal (kidney) dysfunction to avoid unsafe drug concentrations and toxicity.

The patient's wound is filled w dirt which presents a risk for infection. The doctor orders antibiotics to prevent serious systemic infection. The antibiotics are very hydrophilic. Predict the main route of elimination for this antibiotic. Based on this route of elimination, describe a patient condition that would necessitate reducing the dose of the antibiotic

e. Histamine Basinophils release histamine Bosinophil granules contain major basic protein. Neutrophil granules contain myeloperoxidase. IgE antibodies and other immunoglobulins are produced by mature B lymphocytes called plasma cells. Hemoglobin is an oxygen-binding protein that fills the cytoplasm of red blood cells.

What is the main molecule that the leukocyte in this image releases in its contribution to immediate hypersensitivity? a. Major basic protein (MBP) b. Myeloperoxidase (MPO) c. IgE antibodies d. Hemoglobin e. Histamine

Venous thrombi that formed in the deep leg veins

What is the most likely origin of emboli in the pulmonary circulation?

d. Inflammatory infiltrate the release of cellular contents that follows cell necrosis incites tissue inflammation In the core of an ischemic infarct, cell die via necrosis rather than apoptosis (so no apoptotic bodies would be seen); the release of cellular contents that follows cell necrosis incites tissue inflammation (correct answer). Necrotic cell death is microscopically characterized by an increase in the redness (not blueness) of the cell cytoplasm because of protein denaturation (which leads to a higher affinity for the red dye eosin) and degradation of cytoplasmic RNA (which leads to a loss of affinity for the blue dye hematoxylin). Metaplasia and dysplasia are changes in the cell differentiation program that occur in response to chronic stress rather than acute ischemic injury.

What would you expect to MOST LIKELY see in the core of an ischemic infarct two days after its occurrence? Select one: a. Apoptotic bodies b. Dysplasia c. Increased basophilia (blueness) of the cell cytoplasm d. Inflammatory infiltrate e. Metaplasia

b. It is an axial-appendicular muscle.

Which of the follow best describes the latissimus dorsi muscle? Select one: a. It flexes the arm at the shoulder joint. b. It is an axial-appendicular muscle. c. It is considered a deep back muscle. d.It is innervated by dorsal rami.

a. Involuntary, no striations, slow contraction

Which of the following BEST describes smooth muscle? Select one: a. Involuntary, no striations, slow contraction b. Involuntary, striated, fast contraction c. Voluntary, no striations, fast contraction d. Voluntary, no striations, slow contraction

b. Reticulocyte Reticulocytes do not contain a nucleus; they are the immature form of RBCs

Which of the following cells does not have a nucleus? Select one: a. Neutrophil b. Reticulocyte c. Megakaryocyte d. Lymphocyte e. Basophil

c. Absence of associated inflammation apoptosis is characterized by preserved plasma membrane integrity that prevents leakage of cellular content and the resulting tissue inflammation.

Which of the following characteristics is a feature of apoptotic cell death? Select one: a. Enlarged (swollen) cells b. Disrupted plasma membrane integrity c. Absence of associated inflammation d. Nuclear shrinkage (pyknosis) e. Enzymatically degraded cellular contents

Lachman test In this sagittal view MRI the femur, tibia and patella are evident. The labeled structure is the anterior cruciate ligament, seen attaching anteriorly on the tibial condyle and posteriorly on the femoral condyle. The cruciate ligaments are named based on their site of attachment to the tibia. The menisci are fibrocartilaginous disks on the superior aspect of the tibial condyles. The dark shape of the posterior horn of a meniscus may be viewed in this midline view, near the tibia, immediately posterior to the anterior cruciate ligament. Medial and lateral collateral ligaments are located on the sides of the knee, and thus are not visible in the sagittal view through the middle of the knee.

Which of the following is the best clinical test to assess the integrity of the structure indicated by the arrows in this sagittal view MR image?

a. Hyperplasia Hyperplasia: This describes normal cellular proliferation in an organ or tissue that leads to an increase in cell number. Metaplasia refers to the replacement of one fully-differentiated cell type by another, which again is an incorrect description for breast growth. Dysplasia refers to abnormal cellular proliferation with features suggestive of malignancy and with distortion of epithelial organization; these descriptions do not apply to normal breast growth in response to estrogen exposure during puberty

Which term best describes breast growth in response to estrogen during puberty? Select one: a. Hyperplasia b. Hypertrophy c. Heterotopia d. Metaplasia e. Dysplasia

e. Skeletal muscle weakness The difference between bethanecol and parathion is that parathion inhibits Ach- breakdown while bethanechol is a direct acting M agonist. Thus with parathion there is more ACh everywhere and signaling at BOTH N and M receptors is enhanced. Skeletal muscle also has nicotinic receptors that are activated by ACh. Thus in the case of parathion, we expect to see an effect on skeletal muscle. Excessive stimulation of the neuromuscular endplate with ACh leads to paralysis. In the case of parathion poisoning it is the paralysis of the skeletal muscle of the diaphragm that leads to fatal outcomes, as moving air in and out of lungs is mediated by the diaphragm.

While parathion poisoning and an overdose of bethanechol would cause a similar set of signs and symptoms, an important difference is that parathion is much more likely to result in: Select one: a. Blurred vision b. Bradycardia c. Excessive salivation d. Excessive sweating all over the body e. Skeletal muscle weakness

a. Metastatic carcinoma This is a positive antibody staining result, indicating binding of the antibody to keratin protein antigens. The presence of keratin (a protein expressed only by epithelial cells) is an abnormal finding for the brain, which does not normally contain any epithelium. The presence of an epithelial antigen in the brain indicates metastasis from an epithelial tumor. Sarcoma and lymphoma are keratin-negative as they are not of epithelial origin (sarcoma is a malignant tumor derived from mesenchymal cells, while lymphoma is a malignant tumor of lymphocytic origin). Infiltrating glioma is a malignant neoplasm of glial origin; like normal glial cells it resembles, it also does not express keratin. Carcinomas are from endothelial origin

You are evaluating a biopsy from a mass in the brain. The image below shows an antibody stain for the protein keratin, an intermediate filament that is expressed in epithelial cells. Based on this antibody stain, what is the best interpretation?Select one: a. Metastatic carcinoma b.Metastatic sarcoma c.Central nervous system lymphoma d.Normal brain tissue e.Infiltrating glioma

Since the patient presented with severe, sudden onset of adbominal pain it is consistent with an acute process. The intestines show swelling and dark red discoloration and appear to present as a red hemmoragic infarct. Typically, hemmoragic infarcts are common in areas of the body with dual blood supply, however, if there was a previous injury (in this case of the patient a previous heart attack), we can see hemmoragic infarcts due to occulusion. In this case since the patient had a heart attack the emboli oculd have travelled through the system circulation from the mural thrombus in the heart to the abdomen and stopping blood flow. Since there was a previous injury the damaged vessles become leaky and appear red rather than pale.

You are rotating through the Surgery department and observe an abdominal surgery performed on a 65-year-old man (he/him) who presented with severe abdominal pain. He had a heart attack (myocardial infarct) five days before; a photograph of the patient's intestines is shown.Describe the pathologic process that led to the surgical findings and explain how the observed abnormality is related to the patient's known medical history.

Bioavailability is the % of drug that reaches the systemic circulation. The intestine plays a key role in oral delivery of medication. Losing surface anatomy in the intestine can certainly affect oral bioavailability, as surface to absorb drugs across is lost. In contrast, intramuscular (IM) administration delivers drug from the muscle to the blood stream. A change in intestinal surface area will not affect IM bioavailability of drugs.

You are rotating through the Surgery department and observe an abdominal surgery performed on a patient (he/him) who presented with severe abdominal pain. He had a heart attack (myocardial infarct) five days before. During the abdominal surgery, your attending asks you if the findings could have affected the bioavailability of medications the patient took in the period between the heart attack and the surgery. What do you think? In your answer, discuss both oral and intramuscular routes of administration.

Their impulse originates centrally and innervates muscle groups

You see a patient in clinic who reports new neurologic symptoms in their right leg. You perform a careful neurologic exam to determine the motor and sensory involvement. Which of the following statements are true about motor neurons? Select one: a. They provide innervation to an area of skin referred to as a dermatome b. Their cell bodies are located within the dorsal root ganglion c. Their axons are only found in ventral rami d. Their impulse originates centrally and innervates muscle groups

G protein-coupled receptors on PANS-innervated tissue

drug development company is testing a battery of drugs that structurally resemble muscarine and act as muscarinic agonists in an animal model system. The best agonist would target which of the following receptor classes in which of the following locations? Select one: Ion channel receptors on skeletal muscle cells at the neuromuscular junction Ion channel receptors on SANS postganglionic cell bodies Ion channel receptors on PANS-innervated tissues G protein-coupled receptors on PANS postganglionic cell bodies G protein-coupled receptors on SANS postganglionic cell bodies G protein-coupled receptors on PANS-innervated tissue

The patient is limp because nicotine acts on nicotinic receptors on skeletal muscle cells at the neuromuscular junction (NM: in addition to the NN receptors discussed previously), and nicotine overdose leads to overactivation of these receptors. Somewhat counterintuitively, excessive activation of these NM receptors on skeletal muscle causes paralysis: constant depolarization of muscle fibers prevents repolarization and subsequent firing. This poses an immediate danger to life primarily due to paralysis of respiratory muscles (such as the diaphragm and intercostals, which are skeletal muscles, essential for breathing). Without mechanical help with ventilation (moving air in and out of lungs) this paralysis of breathing muscles could lead to death. Atropine would NOT help alleviate this adverse effect because atropine is a muscarinic receptor antagonist, and would have no effect on skeletal muscle, which is innervated by nicotinic receptors (nicotinic muscle receptors (NM).

n 8-month-old child swallowed two cigarette butts while in the care of a sitter. When the mother arrived home, the child was drowsy and limp, so she called 911. On arrival at the hospital, the child was very drowsy, and breathing slowly and with difficulty. A breathing tube was placed and attached to a ventilator. On examination, the child was found to have constricted pupils (miosis), high blood pressure, and diarrhea. The nicotine had also caused the child to produce excess secretions, which were making it hard to get oxygen into the blood in the lungs. Medication was administered to dry the secretions. The child was admitted to the pediatric intensive care unit where they remained minimally responsive for the rest of the night. The next day, the child could breathe on their own. After three days in the hospital, the symptoms resolved and the child was discharged. Why is the child limp? Describe the molecular basis of the symptoms of weakness / paralysis. How might this pose an immediate danger to the child's life? Would the drug used in question 2 help alleviate this adverse effect?

a tissue that forms the lining of the abdominal cavity and thus has a structural, not secretory role

peritoneum

damage to ulnar nerve

physical examination is notable for weakness in finger abduction and adduction in their right hand and decreased sensation in their little finger and medial hand

voluntary, striated, and fast contracting).

skeletal muscle

Metal > bone > soft tissue > fat > air

x-ray densities in order from most dense (whitest) to least dense (darkest):