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Flashcards in usmle2: block4 Deck (75)
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1
Q

HIV protease inhibitors

A

specifically cleave gag (p24) and pol (enzymes) gene products into functional pieces

2
Q

VHL

A
  1. hemangioblastoma
    - cerebellum & retinal
  2. renal cell carcinoma
  3. pheochromocytoma

also cysts in kidney and pancreas

3
Q

how does CO cause hypoxia

A
  1. binds to heme w/ higher affinity than O2
  2. shifts hemoglobin dissociation curve all the way to left (no longer sigmoidal)
    - - doesn’t release o2 anymore
  3. impairs ETC
4
Q

why does HbF have greater affinity for oxygen than HgA?

A

bc HbF doesn’t bind to 2,3BPG

5
Q

where does Cu2+ in wilson’s disease deposit in eye (Kayser-Fleischer ring)

A

cornea: descement’s membrane

6
Q

how does wilson’s disease present

A

30-40s,
hepatitis, splenomegaly, hemolytic anemia

basal gangia (lentiform nuc) damage: dystonia, tremor, dysarthria

kayser-fleisher ring

7
Q

what is the main enzyme responsible for oxidative damage by neutrophils

A

NADPH oxidase, unique
converts O2 into superoxide
main task!

superoxide dismutase acts as either 1. scavenger for these free radicals, in all cells
2. or helps made H202, and w/ MPO, making bleach for further attacking

8
Q

where is NADPH oxidase located

A

membrane protein of phagosome

9
Q

aldehyde dehydrogenase

A

converts aldehyde into carboxylic acid
impt for alcohol metabolism.

blocked by disulfram

10
Q

how does sclerosing adenosis present

A

usu as a density on mammogram / incidentally on biopsy

usu not a mass

11
Q

most common causes of palpable nodular masses in breast

A

fibrocystic changes

usu poorly defined, diffuse increase in consistency throughout breast tissue

often multiple and painful, w. tenderness during premenstrual phase of cycle

12
Q

presentation of mammary duct ectasia

A

ill-defined, palpable periareolar mass

may be confused w/ carcinoma

can have skin retraction and thick creamy or bloody nipple discharge

13
Q

dermoepidermal junction aggregates of large cells that fuse w/ adjacent nests

atypical cells w/ irregular nuclear contours, hyperchromasia, round/spindle shaped

A

dysplastic nevus, which can evolve into melanoma

recall: nevus can be junctional, compound, or intradermal. malignant melanoma w/ pleomorphism

14
Q

squamous cell carcinoma on histology

A

will have keratin pearls

15
Q

basal cell carcinoma on histology

A

basaloid tumors either

  1. budding from epidermis or
  2. residing within the dermis w/ nuclear palisading & retraction artifact evident along periphery of cell nests
16
Q

dysplastic nevus syndrome

A

chr 9p21

‘familial melanoma’

17
Q

dermatofibrosarcoma protuberans

A

fibroblasts in a cartwheel/storiform patteerm
&
supernumerary ring chromosomes

18
Q

langerhans cell histiocytosis

A

prolfierative disorders of dendritic langerhans cells from monocytic lineage

presentation:
lytic bone lesion & skin rash in child
or
recurrent otitis media with a mass involving mastoid bone

cells = functionally immature, do not efficienctly stimulate primart T lymphocytes via antigen presentation

express S-100 (mesodermal origin)
Bierbeck granules = TENIS racket on eM

19
Q

Bierbeck tennis racket granules on EM

A

langerhans cell histiocytosis

20
Q

flumazenil

A

bind to & blocks GABAb at the benzodiazepine binding spot

21
Q
exercise on LV:
HR
LV end-systolic vol
LV end-diastolic vol
LV end-diastolic pressure
A
  • HR increases (less parasymph, more sympth
  • LV end systolic decreases (more preload, less afterload
  • LV end diastolic vol increases

LV end-diastolic pressure does not change
–> decrease in TPR counterbalanced by increased cardiac output

22
Q

clinical signs of alcoholic cerebellar degeneration

A

degenerate cerebellar vermis and anterior cerebellar lobes

wide-based gait, truncal instability, ataxia, nystagmus, dysarthria

23
Q

3 important DNA binding protein domains?

A
  • leucine zippers (alpha helix)
  • helix-loop-helix
  • zinc finger motifs
24
Q

leishmania transmission & histology

A

macrophage w/ amastigotes.
sandfly

kala-azar: spinking fever, hepatosplenomegaly, pancytopenia

25
Q

starting products for pyrimidine synthesis

A

CO2 + glutamine + 2ATP

via carbamoyl phosphate synthetase II

26
Q

where does purine / pyrimidine metabolism occur?

A

cytosol

27
Q

peroxisomes play a role in… (3)

A
  • lipid metabolism (beta oxidation)
  • oxidative reactions
  • purine catabolism
28
Q

positive psoas sign suggests.. (2)

A
  • psoas abscess

- appendicitis

29
Q

quadratus lumborum

A

runs from 12th rib to iliac crest.
helps extend & laterally flex vertebral column
fixes 12th rib during inspiration

30
Q

alcoholic cardiomyopathy

A

dilated cardiomyopathy

31
Q

causes of dilated cardiomyopathy

A

i’m mad my pump failed

iatrogenic
medications (doxorubicin, danorubicin)
alcohol
drugs (cocaine)
myocarditis
pregnancy
familial
32
Q

causes of restrictive cardiomyopathy

A

my pounding ‘art seems held still

metastasis
pompe
amyloidosis
sarcoidosis
hemochromatosis
systemic sclerosis
33
Q

cardio: eccentric hypertrophy vs. concentric

A

eccentric: added in series: dilated cardiomyopathy
concentric: added in parallel: hypertrophy

34
Q

carbolfuschin staining

A

acid-fast staining

retained by mycolic acid

35
Q

presentation of choriocarcinoma

A

trophoblasts with NO VILLI

weeks following..

  • normal birth
  • evacuation of mole
  • following an abortion

can present w/ metastasis to lungs, vagina, brain, liver, or kidney at time of diagnosis

36
Q

placenta accreta results from

A

abscence of decidual layer
placenta stuck to uterine myomatrium

immediate postpartum bleeding secondary to failed placental separation

37
Q

benzoyl peroxide

A

oxidizes bacterial proteins

bacteriostatic against propionibacterium acnes

38
Q

chlorhexadine

A

antiseptic used as skin / dental cleanser

39
Q

acitretin, tretinoin,adapalene, tazarotene

A

retinoid medications, bind nuclear receptors

40
Q

major risk factors for ischemic heart disease. greatest?

A
smoking
HTN
diabetes
dyslipidemia
history of coronary heart disease

greatest: smoking

41
Q

how does smoking risk of ischemic heart disease (2)

A
  1. promotes atherosclerosis
  2. promotes platelet aggregation

have 2-3x risk of nonsmokers

42
Q

alcohol on MI

A

2 standard servings per day, decreases risk of MI

excessive –> other heart problems: HTN, cardiomyopathy, MI

43
Q

how does the vagus n. enter abdomen

A

w/ esophagus (T10)

44
Q

how does the thoracic duct enter abdomen

A

w/ aorta, T12

via aortic hiatus (median arcuate ligament of diaphragm)

45
Q

how does the IVC enter abdomen

A

T8, central tendon of diaphragm

46
Q

why are nitrates first line for angina pectoris

A

decrease both preload and afterload

arterial / venous vasodilation

47
Q

type 2 maturity onset diabetes of young (MODY)

A

mutation in glucokinase (liver & beta pancreatic cells)

even higher Km that it should, higher threshold

48
Q

von gierke mutation

A

glucose 6-phosphatase
only in live (glycogenolysis and gluconeogenesis)

have hepatomegaly and renomegaly

49
Q

fructose / lactose in von gierke

A

bad. can’t be converted to glucose bc defect in gluconeogenesis.

50
Q

deficiency in pompe

A

alpha 1,4 glucosidase
acid maltase
acid alpha glucosidase

51
Q

prognosis of pompe

A

early clinical findings in heart
PAS+ granules in lysosomes

hypotonia, macroglossia, hypertrophic cardiomyopathy, VERY EARLY DEATH

52
Q

pontine hemorrhage

A

often w/ HTN

pinpoint pupils, loss of horizontal gaze, quadriparesis, decerebrate posturing, rapidly evolving coma –> death

53
Q

vasogenic edema

A

often via intracerebral neoplasm
disruption of blood brain barrier –> increased vascular permeability & plasma filtration into cerebral interstitium

vasogenic: fingers: white matter

54
Q

cytotoxic edema

A

increased intracellular fluid WITHIN neurons, glial, endothelial cells. due to impaired Na+ / K+ pump

usu after ischemic insult

cytotoxic: white & grey matter

55
Q

what type of cerebral causes an increased ICP: cytotoxic / vasogenic

A

VASOGENIC –> net gain of fluid in intracranial space

cytotoxic is a shift of fluid from extra/intracellular

56
Q

how does an intracerebral neoplasm increase ICP?

A

vasogenic edema!

disrupts BBB

57
Q

reiter’s syndrome classic & extra symptoms

A

classic: arthritis, urethritis, conjunctivitis
also: cutaneous findings; keratoderma blenorrhagica & balanitis circinata)

58
Q

HLA B27

A

reiter syndrome
psoriatic arthritis
ankylosing spondylitis
IBD

59
Q

only structure in female genital tract w/ 2 epithlium types?

A

cervix:

ecto –> squamocolumnear junction –> endo

ectocervix:
-stratified non-keratinized (like vagina), protrudes into vagina

endocervical canal
between external os -> internal os
-simple columnar epithelium; mucus-secreting glands

squamocolumnar junction:
squamous abrupty converts to columnar endo

60
Q

histology of uterus

A

lined by endometrium –>

EPITHELIAL lining that proliferates and degenerates
(stratum functionalis)

reserve tissue that regenerates stratum functionalis (stratum basalis)

61
Q

histology of fallopian tubes

A

simple ciliated columnar epithlelium

62
Q

histology of ovaries

A

covered externally by simple cuboidal epthelium that ruptures w/ each ovulation

63
Q

most common cause of infectious meningitis in patients w. AIDS

A

cryptococcos neoformans

64
Q

amphotericin B toxicity

A

NEPHROTOXIC
hypokalemia
hypomagnesmia
rental tubular acidosis

65
Q

kaposi sarcoma vs. bacillary angiomatosis

A

kaposi: HHV-8
- lymphocytic infiltrate

bacillary angiomatosis: bartonella hensela
- neutrophilic infiltrate

66
Q

small cell carcinoma secreting ADH causes

A

free water retention –> HYPONATREMIA to try to rid of water

67
Q

squamous cell carcinoma paraneoplastic syndrome

A

PTHrP –> hypercalcemia

68
Q

hypercalcemia + tumor, consider

A

humoral hypercalcemia of malignancy

PTHrP-secreting paraneoplastic syndrome

69
Q

presentation of hypercalcemia

A

fatigue, mental status change, dehydration, nephrolithiasis

can cause polyuria, polydypsia, and dilute urine (like nephrogenic diabetes insipidus) bc impairs renal concentrating ability

70
Q

short peptide medication that is an analog of carboxyl terminal of delta chain of fibrinogen

A

abcixamab, eptifibatide, tirofiban

71
Q

eptifibatide

A
(like abcixamab)
GpIIbIIIa blocker (integrin)

binds to fibrinogen binding site

72
Q

tirofiban

A

like abcixamab

GpIIbIIIa blocker (integrin)

73
Q

ticlopidine / clopidergrel bind..

A

ADP-receptors

GPCRs

74
Q

clopidergel activation requires

A

is a prodrug

must be activated by hepatic cytochrome P-450 enzyme system

*note intxn w/ P450 inhibitors etc

75
Q

zero-order kinetic metabolism

A

rate of enzymatic rxn independent of concentration of substrate

constant AMOUNT of substrate converted to product over time