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Flashcards in usmle2: block 3 Deck (67)
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1
Q
most common cause of epididymitis in heterosexual male
A
c. trachomatis

(homosexual: colon bacterias)
2
Q
what drug can be given w/ penicillin to inhibit metabolism / secretion
A
penicillin + probenicid

prevents reabsorption of uric acid
prevents secretion of penicillin
3
Q
bloom syndrome
A
photosensitivty, short stature, erythema, teleangiectasia

defect in DNA helicase RecQL3

predisposed to lymphoproliferative & GI malginancy
4
Q
where does heriditary nonpolyposis colon cancer usu arise
A
microsatellite instability
mismatch repair defect

usu proximal bowel
5
Q
waxing & waning lymphadenopathy
A
follicular lymphoma
bcl-2 t(14,18)

small cleave w/o nucleoli &
large cell w/ mult nucleoli
6
Q
burkitt lymphoma in industrialized country location
A
ascites & abdominal mass

distal ileum, cecum, mesentary
7
Q
Dupuytren's contractures
A
fixed flexion of fingers
physical manifestation of high estrogen in cirrhotic patients
8
Q
what are lisch nodules
A
pigmented iris hamartomas
9
Q
what's in a neurofibroma
A
schwann cells, fibroblasts, neurites
10
Q
niacin mechanism
A
block hormone sensitive lipase --> reduce formation of VLDL and triglyerides

increases HDL
decrease TG
11
Q
possible niacin side effects
A
prostaglandin mediated:
flushing, pruitis, headache
12
Q
how many of the oocytes we are born w/ remain at puberty?
A
25%
of that, only 400 will be ovulated normally
rest = atesia
13
Q
describe follicular atresia (oocytes)
A
outside basal lamina: THECA cells dedifferentiate & return to poor of ovarian interstitial or stromal cells

in basal lamia: OOCYTE & GRANULOSA cells = apoptosis
14
Q
which antibiotics are teratogen (2)
A
aminoglycoside "a mean guy hit the baby" CN VIII toxicity

tetracycline: discolored teeth
15
Q
which antiseizure drugs are teratogen (3)
A
carbamazepine, phenytoin, valproate (inhibit folate reabsporption

PVC
16
Q
which anti-thyroid drug is a teratogen
A
methimazole
17
Q
loss of heterozygosity
A
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
Q
reason diff alleles have different cuts on restriction enzyme digestion?
A
single nucleotide polymorphisms at restriction enzyme cleavage site
19
Q
how does paclitaxel in a drug-eluting stent work?
A
prevents intimal hyperplasia
(major cause of restenosis)
20
Q
after placing a coronary stent, what is the major cause of restenosis?
A
intimal hyperplasia
prevent w/ paclitaxel / sirolimus
freeze cells in metaphase
21
Q
anti-platelets post stent?
A
given LONGER w/ drug-eluting stents (paclitaxel) bc the rate of endolthelium reformation delayed.

less time w/ bare metal stents
22
Q
which RNA viruses replicate in nucleus?
A
- retroviruses (HIV, HTLV)
- influenza
23
Q
where does influenza replicate
A
nucleus! (+ HIV) all other rna virus = cytoplasm
24
Q
most common cause of pneumonia in infant
A
RSV
25
Q
croup & bronchiolitis in children
bronchitis in adult
A
parainfluenza birus
26
Q
which GLUT is insulin dependent? which tissues
A
GLUT 4: muscle & adipocytes
27
Q
what 2 muscles pull on acromial-end of clavicle? medial portion (3)
A
lateral:
1. deltoid
2. trapezius

medial
1. pec major
2. sternocleidomastoid
3. sternohyoid
28
Q
Ras is downstream
A
GTP-binding protein
downstream RTK
-single transmembrane, dimerize on binding

(not GPCRs)
29
Q
differential of orotic aciduria?
A
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
Q
steps of collagen formation
A
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
Q
most common amino acid in collagen
A
glycine

Gly-X-Y (other: proline, lysine)
32
Q
absence of proline hydroxylation results in
A
cannot form pro-collagen in ER bc triple-helix will be abnormal.
33
Q
what is procollagen
A
formed in ER

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

ultimately secreted by cell
34
Q
presentation of transtentorial herniation
A
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
Q
MLF
A
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
Q
internuclear opthalmoplegia
A
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
Q
conversion
A
conversion: symptoms unexplained by medical condition. preceeded by psychological stressor

not intentionally produced; cause impairment of normal fxn.
38
Q
somatizatin disorder
A
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
Q
what neurological disease makes a protein w/ excess glutamine residues
A
huntington's!
CAG repeats are translated --> polyglutamine
40
Q
4 trinucleotide repeat diseases
A
1. huntington
2. myotonic dystrophy
3. fragile X syndrome
4. friedrich's ataxia
41
Q
confabulation
A
unintentionally fabricates memories that he believes to be true
42
Q
wernicke-korsakoff vs. alzheimers & pseudodementia etc..
A
wernicke-korsakoff may also have ataxia (cerebellar degeneration)

alzheimers, pseudodementia, etc = NORMAL GAIT. more cortical / cognitive issues
43
Q
normal pressure hydrocephalus vs. wernicke-korsakoff
A
both have gait problems

no confabulation in NPH
44
Q
succinyl-CoA and glycine are starting products for..
A
heme synthesis
in mitochondria
via ALA synthase (w/ B6)
45
Q
starting substrates for pyrimidine de novo synthesis
A
glutamine + CO2

also need aspartate + PRPP
46
Q
from where are the nitrogen atoms in urea derivived from
A
ammonia & aspartate
47
Q
patient complaining of fatigue, myalgia, muscle cramps, weakness over a week w/ lots of urination.

due to furosemide or statin?
A
furosemide!
worry about electrolyte abnormalities!
-hypokalemia


statins can cause rhabdomyolysis, but will be ACUTE: generalized weakness, muscle pain, dark urine
48
Q
fatigue, myalgia, muscle cramp, weakness over a week
A
hypokalemia!
49
Q
psoas muscle originates from? how does it enter femur
A
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
Q
3 effects of angII
A
1. direct Na+ retention
2. aldosterone production
3. vasoconstrition
51
Q
HLA codes for
A
MHC class I and II
antigen presentation

class I: HLA A, B, C
class IIL HLA DP, DQ, DR
52
Q
CD40-CD40L
A
CD40 on B cell
CD40L on T cell

needed for B cell activation: class switching
53
Q
CD28-B27
A
CD28 on T cell
B27 on B cell

costimulatory molecule
w/ TCR & MHC interaction

w/o this: T cell -> anergy
54
Q
in what type of arthritis is carpometacarpal joint irritated
A
osteoarthritis (w/ DIP and PIP)

repeated mechanical trauma

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

can feel crepitus on exam
55
Q
chondrosarcoma on X-ray
A
bony destruction at tumor site
56
Q
mechanical ventillation implies fixed (2)
A
-total minute ventilation (TV x RR)
-FiO2
57
Q
generally, atelactasis results in..
A
right-to-left shunt -> hypoexemia

but will have hyperinflation of remaining non-collapsed alveoli, so physiologic dead spaced only increased slightly
58
Q
with fixed ventillation, how can hypercapnea develop
A
increase in pathologic deadspace (i.e. diffusion barrier)
59
Q
microsatellite instability
A
abnormal lengthening or shortening of macrosatellite repeats

related to HNPCC
60
Q
MEN I gene?

MEN II and II gene?
A
MEN I: inactivating mutation in menin tumor supressor

MEN II and II: activating mutation in RET proto-oncogene
61
Q
common presentation of endometriosis (3)? long term consequence?
A
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
Q
CMV colitis
A
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
Q
gag codes for..
A
p24 capsid
64
Q
env codes for ..
A
gp120 (attachment)
gp 41 (fusion)

from cleavage of gp160
65
Q
pol codes for..
A
reverse trancriptase, aspartate protease, integrase
66
Q
mobile flank mass that produces a bruit
A
think: renal cell carcinoma!

(which can obstruct IVC and cause ascities / peripheral edema)
67
Q
consider IVC obstruction in..
A
any patient w/ sudden lower extremity edema