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| Question | Answer |
|---|---|
| What does EBV envelope glycoprotein gp350 bind to? | CR2 or CD21 on surface of B cells |
| In a fib, why aren't all atrial contractions transmitted to the ventricles? | AV nodal refractory period can't keep up |
| Influenz vaccine creates Ab to what? | hemagglutinin - no viral entry into the cell |
| What makes the common fibular nerve susceptible to injury? | courses laterally around neck of the fibula |
| What other abnormalities is imperforate anus commonly associated with? | urogenital: hypospadias, epispadias, bladder exstrophy (much more common than VACTERL) |
| Where are lipids absorbed? | jejunum |
| How do interferons work? | produced in response to viral infection, act as cytokines on neighboring cells, stimulate them to synthesize antiviral proteins that impair synthesis of proteins |
| What calcium channel blocker can be used in tx of subarachnoid hemorrhage? | Nimodipine - cerebral selective drug; prevents vasospasm (that cause focal neurologic signs) |
| What are the two most important factors for osteoclastic differentiation? | M-CSF and RANKL; osteoclasts are differentiated from a monocytic stem cell |
| What is the pathogenesis of Ehlers Danlos Syndrome? | defective cleavage of N and C termini (outside fibroblasts) yields formation of more soluble collagen that does not properly crosslink with other collagen to form proper fibrils |
| What is a serious side effect of Ganciclovir? | Neutropenia (can affect DNA synthesis in hematopoietic stem cell lines) |
| What type of Candidiasis is a pt with deficient CMI more likely to have? neutropenia? | defective CMI -local candidiasis (mucocutaneous, etc) ;neutropenia - systemic candidiasis |
| During anaphylaxis, what else is released from mast cells (besides Histamine)? | tryptase - used as marker for mast cell activation |
| What leads to mast cell degranulation? | cross-linking of multliple membrane-bound IgE Ab by a specific Ag, resulting in IgE receptor aggregation of cell surface |
| What electrolyte abnormalities arise in tx w/ Amphotericin B? | hypokalemia and hypomagnesemia |
| How does digoxin decrease AV nodal conduction? | incr PS tone via Vagus n. |
| What is the MOA of streptomycin? | (-) initiation of protein synthesis by binding to and distorting the structure of the prokaryotic 30s ribosomal subunit |
| How do you tx congenital adrenal hyperplasia? | corticosteroids - suppress ACTH secretion |
| What is superior mesesnteric artery syndrome? | transverse portion of the duodenum is entrapped b/w SMA and aorta causing sx of partial intestinal obstruction (aortomesenteric angle critically decreases either from dimished mesenteric fat or pronounced lordosis) |
| What is the difference b/w FA oxidation of LCFAs and MCFAs? | LCFAs need carnitine transport system to cross inner mitochondrial membrane, MCFAs pass directly through and are activated in the matrix |
| What mutation occurs in Sandhoff's disease? | mutation in hexosaminidase A, same as Tay Sach's but more rapid course |
| Tyrosine is the starting compound for what important products? | Epinephrine, Norepinephrine, T3 and T4, DA, Melanin |
| What can lead to Homocystinuria? | cystathione synthase deficiency, decr affinity for vit B6, decr Homocysteine methyltransferase (mehtionine synthase) or vit B12 deficiency |
| How does Rifampicin work? | blocks intitiation in prokaryotes |
| Where does AA-tRNA synthetase join AA to tRNA? | at the 3' terminal OH |
| Which ribosomal subunit binds to tRNA? to mRNA? | tRNA - larger 60s mRNA - smaller 40s |