Usmle First Aid 1

Front 1

How can neurtoxins be prevented in patients receiving INH?

Back 1

Pyridoxine (Vit B6)

Front 2

On which cells would you expect to find MHC-I? MHC-II

Back 2

MHC-I : almost all nucleated cells

MHC-II: only on APCs

Front 3

Which valve is most commonly involved in bacterial endocarditis and acute rheumatic fever?

Back 3

Mitral

Front 4

What are the toxic side effects of phenytoin?

Back 4

nystagmus, ataxia, diplopia, SLE-like syndrome, induction of P450. Chronic side effects: gingival hyperplasia, peripheral neuropathy, hirsutism, anemia. Teratogen

Front 5

What enzyme catalyzes the rate limiting step in cholesterol synthesis? What class of drugs inhibit this enzyme?

Back 5

HMG-CoA reductase

STATINS

Front 6

What enzyme is deficient in alkaptonuria? What are the manifestations?

Back 6

homogentisic acid oxidase

dark connective tissue, pigmented sclera, urine turns black on standing. Maybe debilitating arthralgias

Front 7

Difference bewteen delusion, illuision, and hallucination

Back 7

hallucination- perception in the anbsence of external stimuli
Illusion- misinterpretation of actual external stimuli
Delusion- false beliefs not shared with other members of culture/subculture that are firmly maintained in spite of obvious proof to the contrary

Front 8

What substrate inhibits conversion of dopamine to NE? What substance inhibits re-uptake of choline by pre-synaptic cholinergic neuron?

Back 8

Rerserpine

Cocaine and TCA

Front 9

Which phase of hepatic metabolism is lost first by geriatric pts? What phase is mediated by cyt P450?

Back 9

they lose phase I first

Phase I: reduction, oxidation, hydrolysis.

Front 10

MOA of propylthioruacil? side effects?

Back 10

inhibit organification and couplin of thyroid hormone synthesis. It also decreaseds peripheral conversion of T4 to T3.

effects: skin rash, agranulocytosis, aplastic anemia

Front 11

Describe how a surgical lesion of subthalamic nucleus might help improve symptoms of Parkinson's?

Back 11

dopamine from the substantia nigra pars compacta binds to D2 receptors in the inhibitory pathway, inhibiting the inhibitory pathway (increases motion). This inhibits the subthalamic nucleus which excites the GPinternus which inhibits thalamus resulting in motion. Surgical lesion of STN will excite the GPi increasing motion.

Front 12

What are the signs of portal hypertension? Signs of liver failure

Back 12

portal htn: esophageal varices --> hematemesis and melena. Peptic ulcer --> melena; splenomegaly, caput medusa, ascites, hemorrhoids

liver failure: coma, sclera icterus, fetor hepaticus, spider veni, gynecomastia, jaundice, testicular atrophy, liver "flap"= asterixis (coarse hand tremor), bleeding tendency (dec Pt and clotting factors), anemia, ankle edema

Front 13

In your own words, describe type 1 (alpha) errors

Back 13

saying that a difference or effect one says exists when it really doesn't. here we mistakenly accept the exp hypothesis. p =

Front 14

What neurotransmitter levels in the brain are either increased or decreased in the following diseases?
*Schizophrenia
*Parkinson's
*Alzheimer's
*Huntington's

Back 14

Schizophrenia: increased dopamine
Parkinson's: decrease dopamine, increase ACh
Alzheimer's: decrease ACh
Huntington's: decrease GABA, decrease ACh

Front 15

What are the actions of AII?

Back 15

Affects baroceptor function; limits reflex brady, which would normally accompany its pressor effects

Front 16

What is the difference between variable expression, incomplete penetrance, pleiotropy, and anticipation?

Back 16

variable expression: nature and severity of the phenotype varies from 1 ind to another

Incomplete penetrance: not all ind with a mutant genotype show the mutant phenotype

pleitropy: 1 gene has > effect on an ind phenotype

anticipation: severity of disease worsens or age of onset of dz is earlier in succeeding generations.

Front 17

Which protozoa are responsible for the following dsieases.

*Chaga's
*amoebic dysentery
*protozoal vaginitis
*malaria
*spiking fevers , hepatosplenomegaly, pancytopenia
*bloating, flatulence, foul smelling diarrhea in campers/hikers.

Back 17

Chaga's: Trypanosoma cruzi
amoebic dysentery: E. histolytica
protozoal vaginitis: Trichomonas vaginalis
malaria: Plasmodium
spking fevers, hepatosplenomegaly and pancytopenia: Leishmania donovani
bloating, flatulence, foul-smelling diarrhea in campers/hikers: G. lamblia

Front 18

What structures can be found in the cavernous sinus?

Back 18

CN III, IV, V1, V2, VI and postganglionic symp fibers en route to orbit. VI = free floating

Front 19

What teratogens cause cervical clear cell adenocarcinoma? (previously admiistered for morning sickness) causes limb defects?

Back 19

clear cell adenocarcinoma: Diethylstilbestrol (DES)

limb defects: Thalidomide

Front 20

Structures that form Hesselbach's triangle? type of hernia protrudes through triangle?

Back 20

Inferior epigastric artery, lateral border of rectus abdominus, inguinal ligament

hernia: direct inguinal

Front 21

most common tumor of urinary tract? usual presenting complaint of a pt? substance exposure that increases risk of developing this tumor?

Back 21

Tansitional cell carcinoma

complaint: none (painless hematuria)

risk: Phenacetin, smoking, aniline dyes and cyclophosphamide