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Flashcards in usmle2: block4 Deck (75)
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1

HIV protease inhibitors

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

2

VHL

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

also cysts in kidney and pancreas

3

how does CO cause hypoxia

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

why does HbF have greater affinity for oxygen than HgA?

bc HbF doesn't bind to 2,3BPG

5

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

cornea: descement's membrane

6

how does wilson's disease present

30-40s,
hepatitis, splenomegaly, hemolytic anemia

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

kayser-fleisher ring

7

what is the main enzyme responsible for oxidative damage by neutrophils

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

where is NADPH oxidase located

membrane protein of phagosome

9

aldehyde dehydrogenase

converts aldehyde into carboxylic acid
impt for alcohol metabolism.

blocked by disulfram

10

how does sclerosing adenosis present

usu as a density on mammogram / incidentally on biopsy

usu not a mass

11

most common causes of palpable nodular masses in breast

fibrocystic changes

usu poorly defined, diffuse increase in consistency throughout breast tissue

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

12

presentation of mammary duct ectasia

ill-defined, palpable periareolar mass

may be confused w/ carcinoma

can have skin retraction and thick creamy or bloody nipple discharge

13

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

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

dysplastic nevus, which can evolve into melanoma

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

14

squamous cell carcinoma on histology

will have keratin pearls

15

basal cell carcinoma on histology

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

dysplastic nevus syndrome

chr 9p21
'familial melanoma'

17

dermatofibrosarcoma protuberans

fibroblasts in a cartwheel/storiform patteerm
&
supernumerary ring chromosomes

18

langerhans cell histiocytosis

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

Bierbeck tennis racket granules on EM

langerhans cell histiocytosis

20

flumazenil

bind to & blocks GABAb at the benzodiazepine binding spot

21

exercise on LV:
HR
LV end-systolic vol
LV end-diastolic vol
LV end-diastolic pressure

-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

clinical signs of alcoholic cerebellar degeneration

degenerate cerebellar vermis and anterior cerebellar lobes

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

23

3 important DNA binding protein domains?

-leucine zippers (alpha helix)
-helix-loop-helix
-zinc finger motifs

24

leishmania transmission & histology

macrophage w/ amastigotes.
sandfly

kala-azar: spinking fever, hepatosplenomegaly, pancytopenia

25

starting products for pyrimidine synthesis

CO2 + glutamine + 2ATP
via carbamoyl phosphate synthetase II

26

where does purine / pyrimidine metabolism occur?

cytosol

27

peroxisomes play a role in... (3)

-lipid metabolism (beta oxidation)
-oxidative reactions
-purine catabolism

28

positive psoas sign suggests.. (2)

-psoas abscess
-appendicitis

29

quadratus lumborum

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

30

alcoholic cardiomyopathy

dilated cardiomyopathy