UWorld_3.28 Flashcards

1
Q

DiGeorge due to…?

A

malformation of third and fourth pharyngeal pouch

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2
Q

Prevention measures for acute organ rejection

A

-calcineurin inhibitors -corticosteroids

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3
Q

Bio active form of pantothenic acid = ?

A

coenzyme A

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4
Q

Rxn that requires coA

A

OAA ==> citrate (first step of Krebs cycle)

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5
Q

Steps in active vit D synthesis

A
  1. sunlight catalyzes first rxn: 7-dehydrocholesterol ==> cholecalciferol 2. @ liver: cholecalciferol ==> 25-hydrocholecalciferol 3. @ kidney: 25-hydrocholecalciferol ==> 1,25-dihydrocholecalciferol [1-alpha hydroxylase] 4. @ vit D excess ==> @ kidney: 25-hydrocholecalciferol ==> 24,25-dihydrocholecalciferol = inactive form [24-alpha hydroxylase]
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6
Q

How does EBV enter B cells?

A

attaches to CD21 = cellular receptor for C3d complement component via gp350

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7
Q

Process of PAH secretion @ proximal tubule

A

-taken up by endothelial cells and secreted into filtrate -accomplished via carrier-mediated transport

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8
Q

Mechanism + testing for mushroom poisoning

A

-amatoxin (e.g. death cap toxin) ==> inhibition of DNA-dependent RNA pol II ==> inhibited mRNA production ==> apoptosis -test = alpha-amantin levels @ serum

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9
Q

Cystinuria presentation/mechanism

A

-defect in transporter of ornithine, lysine, arginine, cystine - ==> nephrolithiasis/renal colic in teens-20s -hexagonal cystine crystals

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10
Q

Histo appearance of carcinoid tumors

A

nests or sheets of cells w/eosinophillic cytoplasm + round/oval stippled nuclei

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11
Q

Trazadone: use, SE

A

use: sedation for insomnia w/depression in conj. w/SSRIs SE: priapism (extended erection)

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12
Q

Venlafaxine: drug category

A

SNRI

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13
Q

Active vs. Inactive RB

A

-active = hypophosphorylate ==I G1/S transition -inactive = hyperphosphorylated

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14
Q

Histoplasma endemic locations

A

Ohio & MS river basins; found in bird and bat droppinga

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15
Q

Most important risk factor for development of intimal tears ==> aortic dissection

A

HTN

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16
Q

Anaplastic definition/characteristics

A

Anaplastic = cells w/complete lack of differentiation 1. loss of polarity/complete disorganization; e.g. sheets 2. variation in cell/nuclear shape and size (pleomorphism) 3. high N-C ratio w/hyperchromic nuclei & clumped chormatin 4. numerous, abnormal mitotic figures 5. giant cell formation

17
Q

First vs. Second Generation Anti-Histamines + examples

A

-first gen= hydroxyzine, promethazine, chlorpheniramine, diphenhydramine ==> antiH1 + SE: antimusc + anti-serotonergic (increased appetite) + alpha-adren (postural hypotension) -second gen = fexofenadine, cetirazine ==> much less SE/sedation

18
Q

Kussmual sign

A

-paradoxically elevated JVP during inspiration (normally decreases) <== due to restriction in RV filling capacity -sign of constrictive pericarditis

19
Q

Characteristics of drugs w/primarily hepatic clearance

A

high lipophillicity & Vd

20
Q

Homeobox ==>

A

transcription factors

21
Q

Causes of upper quad/low quad hemianopsia

A

upper quad = contralateral temporal lesion ==> disruption meyers loop = fibers carrying contralateral visual field upper quadrant vision (#4) lower quad = contralateral parietal lesion ==> disruption of fibers carrying contralateral visual field lower quad vision (#5)

22
Q

Hypo- or hyper-pigmented patches that are more visible after tanning ==> dx?

A
  • Pityriasis versicolor <== Malassezia furfur
  • ==> Spagghetti and meatballs appearance on KOH prep
23
Q

Important allosteric activator of gluconeogenesis

A
  • [@mito] Acetyl-CoA stimulates pyruvate carboxylase: Pyruvate ==> OAA
  • [@mito] OAA ==> malate ==> cytosol
  • [@cytosol] malate ==> OAA ==> PEP [via PEPCK]
24
Q

Molecular stimulators of PMN chemotaxis

A
  • IL-8 <== produces by macrophages
  • C5a = complement = also chemotaxis for eosinophils, monocytes, and basophils
  • LTB4
25
Histone characteristics
* H1 = non-core ==\> increased packaging w/linkage of nucleosome * H2A, H2B, H3, H4 = nucleosome core proteins
26
Sudden, severe headache w/out focal neurologic deficits ==\> sx?
* subarachnoid hemmorhage \<== commonly due to rupture of berry aneurysm @ COW * assoc. w/ED, ADPCKD
27
Hepcidin role/source
* Hepcidin = APR produced by liver parenchyma = major control of iron homeostasis * Hepcidin ==\> internalization of ferroportin on cells ==\> decreased intestinal iron absorption + inhibition of iron release by macs
28
Most common cause of fatigue + new-onset murmur in young adult
bacterial endocarditis
29
Commonly used drugs in MRSA infections + MOA
* Vancomycin: binds D-ala-D-ala subunits ==\> prevents membrane formation * Daptomycin: disrupts cell membrane through formation of transmembrane channels * Linezolid: inhibits protein synthesis by binding 50S subunit
30
SE: Vancomycin Daptomycin Linezolid
* Vanc = Red man; nephrotoxicity * Daptomycin = myopathy & CPK elevation * Linezolid = thrombocytopenia, serotonin syndrome, optic neuritis
31
Formulas for calculating CO
* CO = SV x HR * CO = O2 consumption/arteriovenous O2 difference
32
Cardiac tissue conduction velocity
* Fastest to slowest: * Purkinje * Atrial m. * Ventricular m * AV node * "**P**ark **At** **V**entura **Av**e"