UWorld_3.28 Flashcards
DiGeorge due to…?
malformation of third and fourth pharyngeal pouch
Prevention measures for acute organ rejection
-calcineurin inhibitors -corticosteroids
Bio active form of pantothenic acid = ?
coenzyme A
Rxn that requires coA
OAA ==> citrate (first step of Krebs cycle)
Steps in active vit D synthesis
- 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]
How does EBV enter B cells?
attaches to CD21 = cellular receptor for C3d complement component via gp350
Process of PAH secretion @ proximal tubule
-taken up by endothelial cells and secreted into filtrate -accomplished via carrier-mediated transport
Mechanism + testing for mushroom poisoning
-amatoxin (e.g. death cap toxin) ==> inhibition of DNA-dependent RNA pol II ==> inhibited mRNA production ==> apoptosis -test = alpha-amantin levels @ serum
Cystinuria presentation/mechanism
-defect in transporter of ornithine, lysine, arginine, cystine - ==> nephrolithiasis/renal colic in teens-20s -hexagonal cystine crystals
Histo appearance of carcinoid tumors
nests or sheets of cells w/eosinophillic cytoplasm + round/oval stippled nuclei
Trazadone: use, SE
use: sedation for insomnia w/depression in conj. w/SSRIs SE: priapism (extended erection)
Venlafaxine: drug category
SNRI
Active vs. Inactive RB
-active = hypophosphorylate ==I G1/S transition -inactive = hyperphosphorylated
Histoplasma endemic locations
Ohio & MS river basins; found in bird and bat droppinga
Most important risk factor for development of intimal tears ==> aortic dissection
HTN
Anaplastic definition/characteristics
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
First vs. Second Generation Anti-Histamines + examples
-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
Kussmual sign
-paradoxically elevated JVP during inspiration (normally decreases) <== due to restriction in RV filling capacity -sign of constrictive pericarditis
Characteristics of drugs w/primarily hepatic clearance
high lipophillicity & Vd
Homeobox ==>
transcription factors
Causes of upper quad/low quad hemianopsia
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)
Hypo- or hyper-pigmented patches that are more visible after tanning ==> dx?
- Pityriasis versicolor <== Malassezia furfur
- ==> Spagghetti and meatballs appearance on KOH prep
Important allosteric activator of gluconeogenesis
- [@mito] Acetyl-CoA stimulates pyruvate carboxylase: Pyruvate ==> OAA
- [@mito] OAA ==> malate ==> cytosol
- [@cytosol] malate ==> OAA ==> PEP [via PEPCK]
Molecular stimulators of PMN chemotaxis
- IL-8 <== produces by macrophages
- C5a = complement = also chemotaxis for eosinophils, monocytes, and basophils
- LTB4
Histone characteristics
- H1 = non-core ==> increased packaging w/linkage of nucleosome
- H2A, H2B, H3, H4 = nucleosome core proteins
Sudden, severe headache w/out focal neurologic deficits ==> sx?
- subarachnoid hemmorhage <== commonly due to rupture of berry aneurysm @ COW
- assoc. w/ED, ADPCKD
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
Most common cause of fatigue + new-onset murmur in young adult
bacterial endocarditis
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
SE:
Vancomycin
Daptomycin
Linezolid
- Vanc = Red man; nephrotoxicity
- Daptomycin = myopathy & CPK elevation
- Linezolid = thrombocytopenia, serotonin syndrome, optic neuritis
Formulas for calculating CO
- CO = SV x HR
- CO = O2 consumption/arteriovenous O2 difference
Cardiac tissue conduction velocity
- Fastest to slowest:
- Purkinje
- Atrial m.
- Ventricular m
- AV node
- “Park At Ventura Ave”
