NBME Review / UWorld Review - Questions And Answers

What can be associated with gastric cancer at the gastroesophageal junction? Ans ~ H. pylori What is esophagitis with linear ulcers associated with? Ans ~ CMV What is esophagitis with "punched-out" ulcers associated with? Ans ~ HSV-1 What is esophagitis with white psuedomembrane? Ans ~ Candida What leads to acetaminophen toxicity? Ans ~ Reduced glutathione levels Why does reduced glutathione levels lead to acetaminophen toxicity? Ans ~ Glutathione is not there to bind to glutathione, which leads to a build up of the toxic metabolite, NAPQI Acetaminophen —> NAPQI (toxic) (+ glutathione) —> nontoxic metabolites What protein is important for trafficking proteins to lysosomes? Ans ~ Mannose 6 phosphate What occurs in the Golgi apparatus during cell trafficking? Ans ~ Golgi distributes proteins and lipids from ER to vesicles to go to the plasma membrane or lysosomes What happens if there's a defect with mannose 6-phosphate? Ans ~ The proteins will not be able to go to the lysosomes. They will be secreted extracellularly instead. This is called I cell disease What are physical characteristics caused from a loss in mannose 6 phosphate (I cell disease)? Ans ~ Coarse facial features, gingival hyperplasia, clouded corneas, restricted joint movements, claw hand deformities, kyphoscoliosis, and high plasma levels of lysosomal enzymes Is I-cell disease ( loss of mannose 6 phosphate) an inherited disease or is it sporadic? Ans ~ Inherited; defect in N-acetylglucosaminyl-1-phosphotransferase which prevents the formation of mannose 6 phosphate Would beta blockers be considered reversible or irreversible? Ans ~ Reversible Would beta blockers be considered to be a dose-dependent or dose independent medication? Ans ~ Dose dependent - the effects seen are affected by how much of drug is present What are endotoxins? Ans ~ toxins encoded in plasmids that are part of the structure of the bacteria, like lipopolysaccharides ENDOTOXINS: Edema Nitric Oxide (hypotension) DIC/Death Outer Membrane TNF-alpha O-antigen + core polysaccharide + lipid A X-tremmely heat stable IL-1 and IL-6 Neutrophil chemotaxis Shock (hypotension) When are endotoxins released? Ans ~ Released fron bacteria when they divide, die naturally, or are digested Is LPS an endotoxin or an exotoxin? Ans ~ Endotoxin What is the toxic component of LPS? Ans ~ Lipid A What are the 3 main effects that Lipid A has on body? Ans ~ Macrophage activation Complement activation Tissue factor activation How does lipid A activate macrophages? Ans ~ TLR4/CD14 What cytokines are released from macrophage activation? Ans ~ IL-1, IL-6, TNF-alpha, NO What clinical features do IL-1 and IL-6 have on the body? Ans ~ Fever What clinical features does TNF-alpha have on the body? Ans ~ Fever and hypotension What clinical features does Nitric Oxide have on the body? Ans ~ Hypotension Lipid A activation of complement pathway increases what factors? Ans ~ C3a and C5a What does C3a stimulate in the body? Ans ~ Histamine release: Hypotension and edema What does C5a stimulate in the body? Ans ~ Neutrophil chemotaxis What does tissue factor activation activate? Ans ~ Coagulation cascades; this leads to DIC What is the function of a proteasome? Ans ~ Breaks down proteins that are tagged by ubiquitin What is mulitfactorial inheritance? Ans ~ Many factors are involved in causing a birth defect; usually both genetic and environmental What is an example of a multifactorial inherited birth defect? Ans ~ Cleft lip and palate with no additional birth defects What cytokines do macrophages secrete to activate Th1 lymphocytes? Ans ~ IL-12 What cytokine is secreted by helper T cells to activate the macrophage? Ans ~ INF-gamma What do macrophages form after being activated by INF-gamma? Ans ~ Epithelioid histocytes; important for granuloma formation What is wrong when there is a decreased Th1 response, disseminated mycobacterial and fungal infections, absent granulomas, and low IFN gamma levels? Ans ~ IL-12 receptor deficiency Why are there low IFN-gamma levels with IL-12 receptor deficiency? Ans ~ If Th0 cells can't respond to IL-12, they won't be able to differentiate into Th1 cells and secrete IFN gamma Why is there no granuloma formation in IL-12 receptor deficiency? Ans ~ If Th0 cells can't respond to IL-12, they won't be able to differentiate into Th1 cells and secrete IFN gamma to activate macrophages to form epitheloid histiocytes What other receptor deficiency resembles IL-12 receptor deficiency? Ans ~ IFN-gamma receptor deficiency What is the Michaelis-menten constant equal to? Ans ~ 1/2 V max What causes a fast induction of a gas anesthetic? Ans ~ Low blood solubility What effect does low blood solubility have for a drug? Ans ~ Drug is lipophilic which means it will have fast induction and recovery times What is the loading dose equation? Ans ~ (Cd*Vd)/F(bioavailability) What are the Gq receptors? Ans ~ H1, alpha 1, V1, M1, M3 (HAVe 1 M&M) What receptor does Bethanechol bind to and stimulate? Ans ~ Muscarinic (M3) Gq receptors What effect does Bethanechol have on the bowel and bladder smooth muscle? Ans ~ Activates bowel and bladder smooth muscle to cause movement What is Bethanechol used to treat? Ans ~ Postoperative ileus, neurogenic ileus, urinary retention What type of cancer do kids with Down Syndrome have a higher risk of getting? Ans ~ ALL ("we ALL fall DOWN") What is a cause of a frameshift mutation? Ans ~ Slipped-strand mispairing What is slipped strand mispairing? Ans ~ Illegitimate base pairing in regions of repetitive DNA during replication, coupled with inadequate DNA mismatch repair systems, can produce deletions or insertions of repeat units. Can cause a frameshift mutation What viral process do protease inhibitors prevent? Ans ~ Protein processing What type of cancer is common for an teenage boy who is diagnosed with leukemia? Ans ~ T-ALL What type of T cells are found in the cortex of the thymus? Ans ~ Pre-mature T cells w/ no CD4 or CD8 added yet If presented with blood gas labs, what would anemia look like? Ans ~ Normal Arterial P02; decreased Arterial O2 content Why is there hyperventilation with anemia? Ans ~ To increase amount of 02 in the body Does PCO2 increase or decrease with hyperventilation? Ans ~ Decreases What disease would you expect with very low neutrophils counts in an infant? Ans ~ Congenital neutropenia What type of vaccine is used for Corynebacterium diphtheria? Ans ~ Toxoid vaccine using its purified inactivated toxin What hematologic finding does Aspirin cause? Ans ~ Increases bleeding time