UWorld_3.24

Question 1

Major virulence factor of s. aureus

Answer 1

-Protein A ==> binds Fc of IgG and inhibits compliment, opsonization, and phagocytosis

Question 2

VHL gene locus

Answer 2

3p

Question 3

oncogene loci: Rb, WT-1, NT-1

Answer 3

Rb = 13 WT-1 = 11 NT-1 = 17

Question 4

Candida immune defenses

Answer 4

T-cells = defend against superficial PMNs/phagocytosis = defends against systemic/spread of candida

Question 5

Risks for first-dose rxn to ACE-i

Answer 5

-hypotension, hyponatremia, renal impairment, high renin/aldosterone, heart failure -hypovolemia due to diuretics

Question 6

First arch syndrome

Answer 6

==> malformed structures of first arch: -mandible, maxilla -incus, malleus -temporal bone -zygoma -vomer -palate -associated w/CN V

Question 7

Common cause of coronary sinus dilation

Answer 7

any cause that ==> dilation of right atrium (e.g. pulmonary HTN)

Question 8

common cause of acute eppiglotttis

Answer 8

H. flu <== epiglottitis incidence reduced due to Hib vaccine

Question 9

Electrolytes in adrenal insufficiency

Answer 9

-low aldo ==> decreased Na, increased K -low aldo ==> increased H+ ==> met acidosis = low HCO3- -low HCO3- ==> increased Cl-

Question 10

AR murmur + peak intensity

Answer 10

-early diastolic, high-pitched blowing -best heard leaning forward (valve closer) & during expiration (all L side murmurs) -peak intensity just after closure of the valve

Question 11

Drugs that lead to fat redistribution

Answer 11

-glucocorticoids -HARRT: protease inhibitors (e.g. idinavir)

Question 12

RF = dx of RA =

Answer 12

RF = anti-IgG IgM (but has low specificity) dx = anti-cyclic citrullinated peptide (anti-CCP) = high specificity

Question 13

Recurrent lobar hemorrhages in older adult ==> dx?

Answer 13

-cerebral amyloid angiopathy -beta-amyloid deposited @ vessel wall ==> weak ==> rupture -hemorrhages usually less severe than those due HTN

Question 14

Presentation of sarcoidosis

Answer 14

-typically young, AA female -bilat hilar adenopathy w/non-caseating granulomas -lung parenchymal inflitrates -activated macs ==> elevated Vit D ==> hypercalcemia

Question 15

Example of med that demonstrates tachyphylaxis

Answer 15

-nasal decongestants -negative feedback ==> rebound rhinorrhea after 3 days use

Question 16

BRAF mutation association

Answer 16

-melanoma -BRAF = tyrosine kinase mutation in melanocyte prolif

Question 17

Blood flow to radius of vessel relationship

Answer 17

Flow proportional to 1/r^4

Question 18

flutamide: MOA

Answer 18

-anti-androgen used in prostate cancer tx -competes with T and DHT for binding @ receptor

Question 19

excessive scarring after wound ==>

Answer 19

keloid = excessive collagen

Question 20

Amino acids with 3 titratable protons

Answer 20

• ==> 3 pKa -histadine -arginine -lysine -aspartic acid -glutamic acid -tyrosine -cysteine

Question 21

E. Coli strain that does not ferment + does not produce glucuronidase =

Answer 21

-E. Coli O157:H7 -==> hemorrhagic colitis - has shiga-like toxin ==> inactivation of 60S subunit - ==> HUS

Question 22

Transtentorial herniation ==>

Answer 22

-ipsilateral CNIII lesion = “down and out” -contralateral or ipsilateral hemiparesis -if post. cerebral artery occluded ==> contralateral homonomyous hemianopsia

Question 23

Fendolam: MOA, use

Answer 23

-selective D1 receptor ==> increased cAMP ==> arteriolar dilation -==> increased renal perfusion and natriuresis -used in hypertensive emergencies