8/31/12 Flashcards
What differentiates nafcillin, methicillin, and oxacillin from other penicillins?
Beta-lactamase resistant
Nafcillin is often used empirically to treat skin and soft tissue infections for which _______ is often the cause.
S. aureus
Why aren’t antibiotics used to treat food poisoning caused by S. aureus?
B/c it is usually due to preformed exotoxin.
What dsDNA virus would cause chronic CNS demyelination due to infection of oligodendrocytes (progressive multifocal leukoencephalopathy)?
JC virus
Name 2 important S-100 positive tumors.
Schwannoma and melanoma
What is the only cranial nerve that cannot develop a Schwannoma?
CN II (oligodendrocytes provide myelin)
What is the location of the most common intracranial Schwannoma?
Acoustic neuroma - cerebellopontine angle
What is typical of the growth pattern of Schwannomas?
Dense and loose areas of growth (Antoni A and Antoni B areas)
What is Kussmaul’s sign?
Paradoxical rise in JVD on inspiration.
When and why is Kussmaul’s sign seen?
In chronic constrictive pericarditis. Venous return increases on inspiration, but there is no place for it to go.
What is a common cause of chronic constrictive pericarditis?
Tuberculous caseous pericarditis.
What are the 2 ATP required for each cycle of actin-myosin interaction in muscle fibrils?
1 for detaching the myosin head (cocking) and 1 for taking Ca++ back up into the SR.
What can cause a holosystolic murmur other than a VSD?
mitral regurgitation
What classically causes a mid-systolic click?
mitral prolapse
What is the difference between mitral valve regurgitation and prolapse?
Prolapse is a thickening of the aortic leaflets that may lead to regurg.
Name the 3 major non-selective β-blockers.
Propranolol, nadolol, timolol
What is a drug used for both testicular and small cell lung cancer that induces double-stranded DNA breaks in replicating cells?
etoposide
What is the difference between topoisomerase I and topoisomerase II?
topo I nicks 1 strand of DNA and topo II nicks both.
5-fluorouracil (5-FU) and 5-deoxyuridine are both anti-metabolites that inhibit _______?
thymidilate synthase
The vast majority of Down syndrome cases are due to non-disjunction during what general phase of maternal cell division?
meiosis I
What is the primary route of copper excretion?
Excretion with the bile
Which enxyme is INHIBITED by F-2,6-BP?
fructose-1,6-bisphosphatase
What is is the urine Cl- level in metabolic alkalosis d/t vomiting or NG suction? Does it respond to saline?
low urine Cl-; saline responsive
What is the urine Cl- level in contraction alkalosis (thiazide and loop diuretics)? Responsive to saline?
hi urine Cl-; saline responsive
What is the urine Cl- level in metabolic alkalosis caused by hyperaldosteronism? Responsive to saline?
hi urine Cl-; saline-resistant
What are the treatments necessary for acute infection of the oro-/nasopharynx by C. diphtheriae in order of importance?
- passive immuniZation
- Abx (Penicillin is DoC)
- active immunization (DTaP)
What is the effect of the diphtheria AB exotoxin?
inhibits EF-2!
What is the most common cause of death in acute diphtheria?
cardiomyopathy
