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USMLE Step 1 > UWorld_4.2 > Flashcards

Flashcards in UWorld_4.2 Deck (32)
1

Calculation of absolute risk percent

  • ARP = 100 * (risk in exposed - risk in unexposed)/risk in exposed
  • ARP = 100 * (RR-1)/RR

2

Aging effects on aortic valve

  • aging ==> cell death/necrosis ==> physiologic calcification in the setting of normal calcium levels
  • aortic sclerosis = common in elderly adults
  • can progress ==> calcified aortic stenosis = outflow obstruction

3

Glucagon receptor type + other hormones w/same receptor

  • G-protein coupled receptor
  • binding ==> activated Adenylate Cyclase ==> increased cAMP ==> activated PKA
  • other hormones
    • PTH
    • B-andrenergic
    • TSH

4

Aoritc regurgitation murmur

  • early diastolic murmur 

5

Nitrate adverse effects + prevention

  • ==> reflex tachycardia due to relative hypotension
  • prevented with beta-blockers

6

Metoprolol effects 

  • B1 selective blocker
    • present @ heart & JGA
  • ==> decreased HR
  • ==> blocks renin release by JGA cells

7

Phenotypic mixing definition

  • co-infection of cells with two viruses ==>
  • next gen: one virus obtains nucleocapsid proteins from one virus and contains the genome of the other
  • since no change in underlying genome ==> next gen of progeny revert back to original phenotype

8

Skin finding in Pseudomonas bacteremia

  • ecthyma gangrenosum = cutaneous necrotic disease
  • pseudomonas releases exotoxin ==> bv damage ==> ischemia & necrosis @ skin

9

Beta-thallesemia mutations ==> 

  • defective transcription, processing, or translation of b-globin mRNAs ==> deficiency in quantity/quality of b-globin genes needed to synthesize hemoglobin

10

Chediak-Higashi presentation

  • defect in PMN lysosome fxn ==>
  • neurologic defects
    • nystagmus
  • partial albinism
    • due to abnormal melanin storage
  • immunodeficiency
    • recurrent pyogenic infections, usually staph or strep

11

Most common urea cycle defect

  • defiency of Ornithine transcarbamoylase: ornithine + carbamoyl phosphate ==> citrulline in mitochondria
  • ==> increased blood ammonium levels + increased urinary exrection of orotic acid

12

V2 effects @ medullary collecting duct

  • ==> increased permeability to H20 and urea

13

Initial treatment of severe hypoglycemia

  • in the field/@home: 
    • less severe (mild-moderate) ==> fast-acting carbs; e.g. fruit juice, glucose tablet
    • unconscious: IM glucagon
  • @ hospital: IV glucose

14

Tx for combined T-C and absence seizures

  • valproic acid

15

Baroreceptor afferent nerve conduction

  • Carotid baroreceptor info = CN IX (glossopharyngeal)
  • Aortic baroreceptor info = CN X (vagus)

16

Net excretion calculation =

Net excretion (A) = (inulin CL)(plasma concentration(A)) - tubular reabsorption (A)

17

Winter's formula + use

  • PaCO2 = [1.5 * HCO3-] + 8 +/-2]
  • if PaCO2 is greater than winter's calculation = indication of inability to produce respiratory alkalosis to compensate for metabolic acidosis

18

Amphotericin B: SE

  • Nephrotoxicity and electrolyte abnormalities
  • ==> hypoK and hypoMG
  • hypoK ==> T wave flat, ST-depression, U waves

19

Bethanacol: MOA

musc. antagonist

20

high vs. low selective proteinuria

  • high = albumin & ferritin only (LMW)
  • low = albumin + Ig + macroglob

21

Coll. synth defect in OI

  • defect in procollagen peptidase ==> defect in C/N terminal protein cleavage

22

"Foamy" or "Frothy" urine ==> dx?

proteinuria or bile salts in urine

23

RCC clear cell lineage

proximal tubule cells

24

Calcinuerin fxn

  • calc = protein phosphatase ==> dephosph NFAT ==> trxn factor for IL-2 ==> T cell growth and maturation
  • Cyclosporine & Tacrolimus ==I calcineurin ==> anti-rejection/immunosuppress drugs

25

Unfractionated vs. LMWH 

  • unfractionated = binds ATIII and allows activity against factor Xa and thrombin (inactivation)
  • LMWH ==> ATIII activity against Xa only

26

Parvovirus @ children vs. adults

  • @ children: fever, malaise + erythema infectiosum = rash on cheeks; rahs may also be present extremities ==> trunk
  • @ adults: arthritis in bilateral IP, metacarpal, knee and ankle joints
    • resolves spontaneously (unlike RA)

27

Liver (unique) processing of triglycerides

  • @ adipose tissue: lipase: triglycerides==> glycerol + FFA
  • @ liver: glycerol kinase: glycerol ==> glycerol-3-P ==> DHAP ==> gluconeogen or glycosis

28

Lymph drainage to superficial inguinal lymph nodes

  • all lower extremities, except calf
  • umbilicus to feet w/external genitalia and anus

29

Insulin receptor mechanism

  • insulin ==> tyrosine kinase ==> insulin receptor substrate phosphorylization ==> activation of protein phosphatase
  • protein phosphatase ==> dephosph glycogen synthase = activated glycogen formation
    • also ==> dephosph of fructose-1,6-bisphosphatase = inactive ==> inhibition of gluconeogenesis

30

Most abundant amino acid in collagen

glycine (at least every third)

31

Tongue innervation

  • Motor = CN XII
    • except palatoglossus m. = CN X
  • Sensory
    • Ant 2/3 = CN V3 (mandibular)
    • Post 1/3 = CN IX
    • Post. root/pharynx = CN X
  • Taste
    • Ant 2/3 = CN VII (chorda tympanii)
    • Post 1/3 = CN IX
    • Post. root/pharynx = CN X

32

Succinylcholine: MOA, use

  • MOA: depolarizing NMJ blocker
  • use: rapid induction/intubation or for surgical intubation
  • phase I = augmented by AChEi (e.g. neostigmine)
  • phase II = reversed by AChEi

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