need help with your account or subscription? click here to email us (or see the contact page)
join telegramNEW! discord
jump to exam page:
search for anything ⋅ score predictor (โ€œpredict me!โ€)

NBME 22 Answers

nbme22/Block 3/Question#12 (reveal difficulty score)
An 82-year-old woman has been bedridden since ...
Carboxylation of precursor proteins ๐Ÿ” / ๐Ÿ“บ / ๐ŸŒณ / ๐Ÿ“–
tags:

 Login (or register) to see more


 +6  upvote downvote
submitted by โˆ—humble_station(85)
get full access to all contentpick a username

Warfarin inhibits Vit K dependent synthesis of factors & proteins.

Vit K is necessary for the maturation of clotting factors II, VII, IX, X and protein C & S

So a drug that can inhibit the carboxylation of precursor proteins or in other words inhibit the maturation of the clotting factors will decrease the risk of thrombosis in this patient.

get full access to all contentpick a username

Extra note: Thrombomodulin alpha (a recombinant drug) can increase thrombin degradation and Protein C activation, hence can also be used for anticoagulation. (But this question asked about decrease in which of the following)

+3/- apurva(101)


 +2  upvote downvote
submitted by โˆ—haliburton(225)
get full access to all contentpick a username

warfarin inhibits the synthesis of factors II, VII, IX, X, C, and S by blocking reduction of oxidized vitamin K. The enzyme Epoxide Reductase is inhibited by warfarin. The reduced (active) form of vit. K is a cofactor for gamma-glutamyl carboxylase.

get full access to all contentpick a username
link981  So factors II, VII, IX, and X are precursor proteins? GTFO +2



 +0  upvote downvote
submitted by โˆ—humble_station(85)
get full access to all contentpick a username

Warfarin inhibits Vit K dependent synthesis of factors & proteins.

Vit K is necessary for the maturation of clotting factors II, VII, IX, X and protein C & S

So a drug that can inhibit the carboxylation of precursor proteins or in other words inhibit the maturation of the clotting factors will decrease the risk of thrombosis in this patient.

get full access to all contentpick a username
ajss  this is why warfarin is given as prophylaxis after this type of surgeries +



 -2  upvote downvote
submitted by โˆ—sup(31)
get full access to all contentpick a username

Why not PGI2 by way of ASA? Especially given other answer choices of proteins C + S: doesn't warfarin also suppress these?

get full access to all contentpick a username
imnotarobotbut  Protein C and S are ANTI-thrombotic, so although Warfarin does decrease them, they wouldn't decrease the patient's risk for thrombosis +1
epr94  the question ask "suppression" of which one will decrease risk of thrombosis if you suppress C and S which and anti-thrombotic you get thrombotic +3



Must-See Comments from nbme22

sacredazn on Unrearranged immunoglobulin gene
seagull on Decreased binding of RNA polymerase
seagull on Anticholinergic
liverdietrying on Release of stored thyroid hormone from a ...
keycompany on Negative nitrogen balance
kernicterusthefrog on Displacement
mcl on Area labeled โ€˜Dโ€™
joha961 on Displacement
imgdoc on Area labeled โ€˜Cโ€™ (Abducens nucleus, right)
alwaysanonymous on 25 mL/cm H2O
drdoom on 1 in 600
seagull on Glutamine
bubbles on Acute retroviral infection
yotsubato on Phase variation

search for anything NEW!