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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