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Rituximab

Mechanism = Monoclonal antibody against CD20, which is found on most B-cell neoplasms.

Use = B-cell Non-Hodgkin lymphoma, CLL, ITP, rheumatoid arthritis, TTP, AIHA, MS.

Adv effects = Increased risk of progressive multifocal leukoencephalopathy in patients with JC virus.

tyrionwill  low IgG in response to infection/vaccination leads to broad bacteria and virus infection or reactivation. bacteria: strep pneumonia, Hib virus: JC, HBV, CMV... +  


MDMA is the only hallucinogen that has sympathetic activity as it is derived from methamphethamines ( look at its name) ... that explains everything.

tyrionwill  Yes, good point to remember. In the category of FA stimulants, 2 agents has sympathetic activity: 1)MDMA; 2)PCP +  
jackie_chan  Basically how I solved it, all the other drugs are downers +  
jackie_chan  Even tho ketamine has sympathomemetic effects, they would be widly tripping, they dont call it falling into a K-hole for nothing. +  


submitted by yotsubato(646),

"Children exhibit behavior incongruent with their age and development" in sexual abuse.

tyrionwill  mostly the age difference exceeds 4 years trigger so called "incongruent with their age". age incongruence plus signs of being forced, like this case which the 4-year-old boy was found crying, lead to suspicious more on sex abuse than sex play. +1  


Bortezomib, carfilzomib

Mechanism = Proteasome inhibitors, induce arrest at G2-M phase and apoptosis.

Use = Multiple myeloma, mantle cell lymphoma.

Adv Effects = Peripheral neuropathy, herpes zoster reactivation

tyrionwill  under Bortezomib, the proteasome cannot digest viral Ag and presents it to the membrane-bonded MHC-I. Therefore CD8-Tc cannot recognize the host cells containing relapsed VZV. That is probably why shingles is one of the popular side effect of Bortezomib. +  


submitted by krewfoo99(58),

So basically what this is saying that DNA will be transmitted to the progeny not RNA. So DNA will replicate in the G2 phase and transfer of DNA material to progeny will occur in the M phase. The RNA may be mutated and making defective products, but this will not transmit into the progeny, thus not affecting species survival based on RNA mutations.

bk2458  makes sense!! +  
almondbreeze  good work +  
tyrionwill  the question asks the reason of no impact on its survival. if a protein translated from a wrong mRNA loses its function, how can we say the bacteria will still survive well? if there is always fatal error happened during mRNA transcription, and always leading to fatal dysfunctional protein, how can the bacteria and its progeny still survive? so the point will be whether the fatal errors will always happen during transcription? I dont know... +  
tyrionwill  actually FA and NBME seem to have made a wrong statement that RNA polymerase has no proofreading function. RNA polymerase has more fidelity to DNA than DNA polymerase by 2 ways: 1) highly selection of correct nucleotide, and 2) proofreading. (Jasmin F Sydow and Patrick Cramer, RNA polymerase fidelity and transcriptional proofreading: https://pure.mpg.de/rest/items/item_1940413/component/file_1940417/content) however, if survival of the species refers only to the reproduction of progeny, mRNA mutation has nothing with the progeny. +1  


submitted by krewfoo99(58),

So basically what this is saying that DNA will be transmitted to the progeny not RNA. So DNA will replicate in the G2 phase and transfer of DNA material to progeny will occur in the M phase. The RNA may be mutated and making defective products, but this will not transmit into the progeny, thus not affecting species survival based on RNA mutations.

bk2458  makes sense!! +  
almondbreeze  good work +  
tyrionwill  the question asks the reason of no impact on its survival. if a protein translated from a wrong mRNA loses its function, how can we say the bacteria will still survive well? if there is always fatal error happened during mRNA transcription, and always leading to fatal dysfunctional protein, how can the bacteria and its progeny still survive? so the point will be whether the fatal errors will always happen during transcription? I dont know... +  
tyrionwill  actually FA and NBME seem to have made a wrong statement that RNA polymerase has no proofreading function. RNA polymerase has more fidelity to DNA than DNA polymerase by 2 ways: 1) highly selection of correct nucleotide, and 2) proofreading. (Jasmin F Sydow and Patrick Cramer, RNA polymerase fidelity and transcriptional proofreading: https://pure.mpg.de/rest/items/item_1940413/component/file_1940417/content) however, if survival of the species refers only to the reproduction of progeny, mRNA mutation has nothing with the progeny. +1  


submitted by nor16(43),

in ß Thalassemia there is HbA2 increase and HbA decreases, even in ß+ , normal electrophoresis rules this out. same for A)-C)

tyrionwill  Yes! The key point is the normal electrophoresis. Hemoglobin will not show any abnormalities until least one single allele of Hb fully develops mutation. alpha chain of Hb is contributed by two points within one single allele, while beta chain of Hb is made of only one point in one single allele, therefore: -- in alpha thalassemia Hb electrophoresis will be normal if only one point gets mutation, i.e., aa/a- which we call it the "minima type". If two points get mutation, i.e., cis aa/--, or trans a-/a-, the "minor type", the Hb electrophoresis will be either abnormal(Hb Barts 3-8%) or still normal. overall, we assume the parent both are the minima type, so their children have 50% chance to be the minor type, 25% to be fully normal, and 25% to be the trans minor. -- However in beta thalassemia, the mutation of one allele will lead to whole allele changed, so we just need the mutation once to generate an abnormal Hb electrophoresis result. +  


submitted by sajaqua1(390),

Gynecomastia, spider angiomata, and hypogonadism (as well as palmar erythema) are all signs of excess estrogen. The liver in patients with hepatic disease is impaired and so cannot clear estrogen sufficiently. Six 12 oz beers daily (72 oz, or half a gallon) is too much, and is destroying his liver.

uslme123  No hepatosplenomegaly, ascites, or edema through me off. We that being said, I shied away from cirrhosis. I thought that he showed signed of depression, so I went with the thyroid. But who's to say he isn't injection anabolic steroids?! +2  
catch-22  The principle is you can get liver dysfunction without having HSM, ascites, etc. Liver disease is on a progressive spectrum. +8  
notadoctor  He likely has hepatitis B/C given his history of intravenous drug use. I believe both can have liver dysfunction but may or may not have ascites, whereas the type of damage we would expect from alcohol that would match this presentation would also show ascites. +  
charcot_bouchard  For Ascities u need to have portal HTN. Thats a must. (unless exudative cause like Malignancy) +1  
paulkarr  For anyone who needs it; the FA photo is kinda burned into my mind for these questions. NBME has some weird infatuation with this clinical presentation.. FA (2019) Pg: 383 "Cirrhosis and Portal HTN". +1  
snripper  @paulkarr the problem was that the FA image was burned into my mind so without no ascites or edema threw me off of cirrhosis. +  
tyrionwill  cirrhosis doesn't present hepatomegaly, instead, the liver could be shrunken. +  


submitted by sajaqua1(390),

Because the baby's mother has Type 1 Diabetes mellitus, it is plausible that they had elevated blood glucose levels during or shortly before birth. Insulin does not cross the placenta, but glucose does, so during birth the neonate would have been hyperglycemic. This would lead to the neonatal pancreas releasing insulin, driving glucose into cells and turning down gluconeogenesis; this is why the baby is hypoglycemic right now.

B) Decreased glycogen concentration- I don't know the glycogen concentration compared to an adult patient, but a decrease in glycogen concentration would indicate glycogen/glucose release, which would not be a hypoglycemic state. C) Decreased glycogen synthase activity- decreased glycogen synthase activity indicates energy catabolism, and would lead to higher serum glucose levels. D) Decreased serum insulin concentration- decreased serum insulin would lead to higher levels of glucose in serum. E) Increased serum insulin-like growth factor- IGF does not bind nearly as well to insulin receptors as insulin does, and so would have to be in extremely high concentrations to have this effect. IGF is associated with somatic growth and muscle development.

yotsubato  His glycogen concentration is high, since he's been hyperglycemic with lots of insulin until birth. +3  
alexb  Also explains why he's 12 pounds. +2  
krewfoo99  Also, think of it like this: Insulin causes hypoglycemia, thus this baby must have increased insulin. It is also an anaobolic hormone which is clear by the babys weight. Insulin increases glycogen synthase activity, and causes an increase in concentrations of glycogen. Decrease in insulin would do exactly the opposite +1  
tyrionwill  fetus of a mom with DM will develop pancreatic beta cell hyperplasia, which leads to insulinemia trying to reduce the blood glucose. after birth, the excessive blood glucose will be automatically withdrawn while the insulin at that moment is still high, which leads to hypoglycemia. +  


submitted by uslme123(22),

This question makes no sense to me. She has an extremely low opening pressure yet has signs of increased intracranial pressure. Did they mean to put 32 cm H20?????????

uslme123  Standard lab values are incorrect, way to go NBME. +2  
wutuwantbruv  I think they mean to put mm Hg. Normal CSF pressure is about 100-180 mm H20 which equates to about 8-15 mm Hg. +2  
alexb  I lost a bit of time wondering about that ugh lol +1  
mjmejora  I thought there must be an obstruction in the ventricles somewhere preventing csf from getting to the spine. so pressure is low in spinal tap but in the head it must be really high. +  
donttrustmyanswers  Does anyone have clarification on this question? +  
llamastep1  Pseudo tumor cerebri can have normal ICP. Who knew +  
tyrionwill  Hi, mjmejora, MRI did not see anything abnormality, couldn't this mean that there was no obstruction in the ventricles? +  


submitted by usmleuser007(280),

NVM got it.

Just FYI: the CI was stated to be from 110-116 with 95% and mean of 113. So, on either there are two SD on either sides of 113 (the mean) that give the 95%.

116-113= 3 within 2SD above the mean 113-110= 3 within 2SD below the mean

3 divided by the 2 SD = 1.5 per SD.

to get from 95% to 99% you have to incorporate one more SD (3 SD) on either sides of the mean (113)

Therefore; at 99% CI 110-1.5= 108.5 CI 116+1.5= 117.5

Round these up and you get 108-118

tyrionwill  95%CI = M ± Z(SE) instead of SD 116-113 = 3 within 2SE, not 2SD SE = SD/extract the square root of n = SD/2 and SD = 2SE +  
tyrionwill  Sorry I made a mistake, neglect the abobe +  
tyrionwill  if you use Mean ± 2SD = 95%CI to know SD, then use Mean ± 3SD to only know 99.7%CI, a bit larger than 99%CI +  


submitted by usmleuser007(280),

NVM got it.

Just FYI: the CI was stated to be from 110-116 with 95% and mean of 113. So, on either there are two SD on either sides of 113 (the mean) that give the 95%.

116-113= 3 within 2SD above the mean 113-110= 3 within 2SD below the mean

3 divided by the 2 SD = 1.5 per SD.

to get from 95% to 99% you have to incorporate one more SD (3 SD) on either sides of the mean (113)

Therefore; at 99% CI 110-1.5= 108.5 CI 116+1.5= 117.5

Round these up and you get 108-118

tyrionwill  95%CI = M ± Z(SE) instead of SD 116-113 = 3 within 2SE, not 2SD SE = SD/extract the square root of n = SD/2 and SD = 2SE +  
tyrionwill  Sorry I made a mistake, neglect the abobe +  
tyrionwill  if you use Mean ± 2SD = 95%CI to know SD, then use Mean ± 3SD to only know 99.7%CI, a bit larger than 99%CI +  


submitted by usmleuser007(280),

NVM got it.

Just FYI: the CI was stated to be from 110-116 with 95% and mean of 113. So, on either there are two SD on either sides of 113 (the mean) that give the 95%.

116-113= 3 within 2SD above the mean 113-110= 3 within 2SD below the mean

3 divided by the 2 SD = 1.5 per SD.

to get from 95% to 99% you have to incorporate one more SD (3 SD) on either sides of the mean (113)

Therefore; at 99% CI 110-1.5= 108.5 CI 116+1.5= 117.5

Round these up and you get 108-118

tyrionwill  95%CI = M ± Z(SE) instead of SD 116-113 = 3 within 2SE, not 2SD SE = SD/extract the square root of n = SD/2 and SD = 2SE +  
tyrionwill  Sorry I made a mistake, neglect the abobe +  
tyrionwill  if you use Mean ± 2SD = 95%CI to know SD, then use Mean ± 3SD to only know 99.7%CI, a bit larger than 99%CI +  


submitted by mousie(137),

why does treatment of hypothyroid (with levothyroxine I'm assuming) increase risk for myopathy? I chose it simply bc its a common adverse effect of statins but I don't really understand how treating hypothyroidism at the same time would have anything to do with it ??? help please!

yb_26  They are just asking about side effect of statins, not about treatment of hypothyroidism +5  
mjmejora  Hypothyroidism is just a red herring. +  
ususmle  statins cause both hepatotoxic and mypopathy so I want for hepatotoxic:( I thought usmle expects different stuff +1  
drzed  Statins don't cause 'toxic hepatitis' they just cause a mild asymptomatic rise in LFTs that is reversible with discontinuation of the drug. The more worrisome side effect is of course, myopathy +1  
tyrionwill  statins cause both liver injury and myopathy in a dose related, so kidney failure increases their dose, which leads both liver and muscle risk elevated; Pravastatin is said less liver concerns but the myopathy, so choose myopathy when renal failure. +  


submitted by hungrybox(586),

Fucking NBME test writers lmao

Me: "Wait... isn't the answer 25.9? How come I don't see it here."

NBME: "Oh yeah, we rounded it."

Me: "To 30? I don't see that here, either..."

NBME: "No, to 28.8"

tyrionwill  When I got 25.9 and found nothing exactly matched, I guessed that the maintenance dose might be a bit more due to the bioavailability. So this antibiotic probably was not an I.V. formula, but an oral one, with a roughly 90% BA. +1  
eradionova  Well then it could have been equally likely that it had a 50% BA and the answer would be 51.8 exactly. I almost considered picking that but in the end stuck with the one that was closest to my answer lol +  


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