Mechanism ==> decreased RBF and increased FF
constriction of efferent arteriole
Pathophysiology of narcolepsy
-low levels of NT orexin (hypocretin) which normally promotes wakefullness & suppresses REM sleep phenomenon
Positive cyanide-nitroprusside urine test ==> dx?
-cysteinuria = defect of cysteine transporters @ proximal renal tubule - ==> recurrent gallstones @ young age
Metyrapone stimulation test purpose/mechanism
-tests integrity of HPA axis -blocks cortisol synthesis via inhibition of 11B-hydroxylase -decreased neg. feedback ==> ACTH surge
Antidote for NE drip-mediated tissue necrosis
-alpha-1 receptor blocker -e.g. phentolamine
Tx of calcium oxalate kidney stones
hydrochlorothiazide: blocks Na/Cl transporter @ lumen ==> activation of Na/Ca exchanger ==> increased Na w/in cell in exchange for increased Ca reabsorbed
How does s. viridans adhere to valves ==> endocarditis?
-previous valve damage + fibrin deposition is required to adhere
Formation of env HIV genes
glycosylation ==> gp160 + proteolytic cleavage @ ER ==> gp120 + gp41 = mediators of target fusion
Mechanism of C. diff exotoxins
-toxins A & B -disruption of Rho-regulatory proteins & actin cystoskeleton elements ==> impaired cytoskeleton maintence - + disruption of tight jxns -A = more enterotoxic -B = more cytotoxic
Only sensory pathway that doesn't relay through thalamus
Cavitary lesion in lung + air fluid levels on xray ==> dx?
lung abscess (possibly aspiration pneumo)
Adenosine: MOA, use, SE
-MOA: slowing conduction through AV node by hyperpolarizing nodal & conducting cells -use: drug of choice in paroxysmal SVT -SE: flushing, chest buring (bronchospasm), hypotension, high-grade AV block