usmle2: block 3 Flashcards Preview

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Flashcards in usmle2: block 3 Deck (67):
1

most common cause of epididymitis in heterosexual male

c. trachomatis

(homosexual: colon bacterias)

2

what drug can be given w/ penicillin to inhibit metabolism / secretion

penicillin + probenicid

prevents reabsorption of uric acid
prevents secretion of penicillin

3

bloom syndrome

photosensitivty, short stature, erythema, teleangiectasia

defect in DNA helicase RecQL3

predisposed to lymphoproliferative & GI malginancy

4

where does heriditary nonpolyposis colon cancer usu arise

microsatellite instability
mismatch repair defect

usu proximal bowel

5

waxing & waning lymphadenopathy

follicular lymphoma
bcl-2 t(14,18)

small cleave w/o nucleoli &
large cell w/ mult nucleoli

6

burkitt lymphoma in industrialized country location

ascites & abdominal mass

distal ileum, cecum, mesentary

7

Dupuytren's contractures

fixed flexion of fingers
physical manifestation of high estrogen in cirrhotic patients

8

what are lisch nodules

pigmented iris hamartomas

9

what's in a neurofibroma

schwann cells, fibroblasts, neurites

10

niacin mechanism

block hormone sensitive lipase --> reduce formation of VLDL and triglyerides

increases HDL
decrease TG

11

possible niacin side effects

prostaglandin mediated:
flushing, pruitis, headache

12

how many of the oocytes we are born w/ remain at puberty?

25%
of that, only 400 will be ovulated normally
rest = atesia

13

describe follicular atresia (oocytes)

outside basal lamina: THECA cells dedifferentiate & return to poor of ovarian interstitial or stromal cells

in basal lamia: OOCYTE & GRANULOSA cells = apoptosis

14

which antibiotics are teratogen (2)

aminoglycoside "a mean guy hit the baby" CN VIII toxicity

tetracycline: discolored teeth

15

which antiseizure drugs are teratogen (3)

carbamazepine, phenytoin, valproate (inhibit folate reabsporption

PVC

16

which anti-thyroid drug is a teratogen

methimazole

17

loss of heterozygosity

relevant to oncogenesis

person born w/ single defective copy of tumor supressor gene does not develop malignancy until some cells spontaneously mutate other gene

18

reason diff alleles have different cuts on restriction enzyme digestion?

single nucleotide polymorphisms at restriction enzyme cleavage site

19

how does paclitaxel in a drug-eluting stent work?

prevents intimal hyperplasia
(major cause of restenosis)

20

after placing a coronary stent, what is the major cause of restenosis?

intimal hyperplasia
prevent w/ paclitaxel / sirolimus
freeze cells in metaphase

21

anti-platelets post stent?

given LONGER w/ drug-eluting stents (paclitaxel) bc the rate of endolthelium reformation delayed.

less time w/ bare metal stents

22

which RNA viruses replicate in nucleus?

- retroviruses (HIV, HTLV)
- influenza

23

where does influenza replicate

nucleus! (+ HIV) all other rna virus = cytoplasm

24

most common cause of pneumonia in infant

RSV

25

croup & bronchiolitis in children
bronchitis in adult

parainfluenza birus

26

which GLUT is insulin dependent? which tissues

GLUT 4: muscle & adipocytes

27

what 2 muscles pull on acromial-end of clavicle? medial portion (3)

lateral:
1. deltoid
2. trapezius

medial
1. pec major
2. sternocleidomastoid
3. sternohyoid

28

Ras is downstream

GTP-binding protein
downstream RTK
-single transmembrane, dimerize on binding

(not GPCRs)

29

differential of orotic aciduria?

1. if also hyperammonia: OTC
build up of carbamoyl phosphate --> shunt to de novo pyridamine synthesis --> orotic acid temp base

2. w/o hyperammonia --> orotic aciduria

30

steps of collagen formation

in ER:
hydroxylation of proline/lysine
glycosylation of some lysine
assembly of triple helix = PROCOLLAGEN
--requires 1. H bonding of hydroxylated groups & 2. disulfide bonding w/ C-terminals

secrete procollagen into golgi -> out of cell

in ECM
cleave N & C terminus -> collagen fibril
crosslink via lysyl oxidase

31

most common amino acid in collagen

glycine

Gly-X-Y (other: proline, lysine)

32

absence of proline hydroxylation results in

cannot form pro-collagen in ER bc triple-helix will be abnormal.

33

what is procollagen

formed in ER

-triple helix (thanks to hydroxylation of proline/lysine) and disulfide bonds of C terminal groups

ultimately secreted by cell

34

presentation of transtentorial herniation

uncal
-fixed and dilated pupil on ipsilateral side
-can produce ipsilateral or contralateral hemiparesis (cerebral peduncle)
(compress external parasympathetics)

ipsilateral hemiparesis: kernohan phenomenon
- due to shifting of entire brainstem, compresses contralateral cerebral peduncle against rim of tentorium

35

MLF

links nuclei of CN VIII proprioception from inner ear w/ nuclei for eye movements

also allows for conjugate lateral gaze, communication between

also: CNVI and CNIII nuclei

when CNVI nucleus activates lateral rectus, will also activate CNIII for medial rectus --> conjugate movement

damaged in multiple sclerosis

36

internuclear opthalmoplegia

lesion to MLF
problem w/ conjugate lateral gaze

CNVI nuclei fails to tell contralateral CNIII to contract medial rectus (while telling ipsilateral lateral rectus)

will see nystagmus in abducting eye (overstimulation by CN VI)

37

conversion

conversion: symptoms unexplained by medical condition. preceeded by psychological stressor

not intentionally produced; cause impairment of normal fxn.

38

somatizatin disorder

multiple physical complaints before age 30
-4 pain symptoms: 2 GI, one sex, one neuro
-unexplained by general medical condition
-not artificially produced
-causing significant impairment

39

what neurological disease makes a protein w/ excess glutamine residues

huntington's!
CAG repeats are translated --> polyglutamine

40

4 trinucleotide repeat diseases

1. huntington
2. myotonic dystrophy
3. fragile X syndrome
4. friedrich's ataxia

41

confabulation

unintentionally fabricates memories that he believes to be true

42

wernicke-korsakoff vs. alzheimers & pseudodementia etc..

wernicke-korsakoff may also have ataxia (cerebellar degeneration)

alzheimers, pseudodementia, etc = NORMAL GAIT. more cortical / cognitive issues

43

normal pressure hydrocephalus vs. wernicke-korsakoff

both have gait problems

no confabulation in NPH

44

succinyl-CoA and glycine are starting products for..

heme synthesis
in mitochondria
via ALA synthase (w/ B6)

45

starting substrates for pyrimidine de novo synthesis

glutamine + CO2

also need aspartate + PRPP

46

from where are the nitrogen atoms in urea derivived from

ammonia & aspartate

47

patient complaining of fatigue, myalgia, muscle cramps, weakness over a week w/ lots of urination.

due to furosemide or statin?

furosemide!
worry about electrolyte abnormalities!
-hypokalemia


statins can cause rhabdomyolysis, but will be ACUTE: generalized weakness, muscle pain, dark urine

48

fatigue, myalgia, muscle cramp, weakness over a week

hypokalemia!

49

psoas muscle originates from? how does it enter femur

T12-L4
combines w/ illiacus
forms common tendon to attach to lesser trochanter of femur (medial aspect)

travels below inguinal ligament.

pus can form near groin.

50

3 effects of angII

1. direct Na+ retention
2. aldosterone production
3. vasoconstrition

51

HLA codes for

MHC class I and II
antigen presentation

class I: HLA A, B, C
class IIL HLA DP, DQ, DR

52

CD40-CD40L

CD40 on B cell
CD40L on T cell

needed for B cell activation: class switching

53

CD28-B27

CD28 on T cell
B27 on B cell

costimulatory molecule
w/ TCR & MHC interaction

w/o this: T cell -> anergy

54

in what type of arthritis is carpometacarpal joint irritated

osteoarthritis (w/ DIP and PIP)

repeated mechanical trauma

see: joint space narrowing, subchondral sclersosis, eburnation, cyst formation, osteophytes

can feel crepitus on exam

55

chondrosarcoma on X-ray

bony destruction at tumor site

56

mechanical ventillation implies fixed (2)

-total minute ventilation (TV x RR)
-FiO2

57

generally, atelactasis results in..

right-to-left shunt -> hypoexemia

but will have hyperinflation of remaining non-collapsed alveoli, so physiologic dead spaced only increased slightly

58

with fixed ventillation, how can hypercapnea develop

increase in pathologic deadspace (i.e. diffusion barrier)

59

microsatellite instability

abnormal lengthening or shortening of macrosatellite repeats

related to HNPCC

60

MEN I gene?

MEN II and II gene?

MEN I: inactivating mutation in menin tumor supressor

MEN II and II: activating mutation in RET proto-oncogene

61

common presentation of endometriosis (3)? long term consequence?

dysmenorrhea
pelvic pain
dyspareunia

can have infertility: pelvic adhesions, fibrosis. distort pelvic anatomy and impair transport to oviduct.

if in bowel/bladder wall, can have painful defecation/urination too.

62

CMV colitis

2nd most common CMV manifestation after CMV retinitis in HIV patients.

fever, anorexia, weight loss, abdominal pain.

mucosal erythema, erosion, ulcer

giant cells w/ large ovoid nucleus w/ centralized intranuclear inclusions "Cowdry". like one big owel eye.

63

gag codes for..

p24 capsid

64

env codes for ..

gp120 (attachment)
gp 41 (fusion)

from cleavage of gp160

65

pol codes for..

reverse trancriptase, aspartate protease, integrase

66

mobile flank mass that produces a bruit

think: renal cell carcinoma!

(which can obstruct IVC and cause ascities / peripheral edema)

67

consider IVC obstruction in..

any patient w/ sudden lower extremity edema