usmle2: block 3 Flashcards
most common cause of epididymitis in heterosexual male
c. trachomatis
homosexual: colon bacterias
what drug can be given w/ penicillin to inhibit metabolism / secretion
penicillin + probenicid
prevents reabsorption of uric acid
prevents secretion of penicillin
bloom syndrome
photosensitivty, short stature, erythema, teleangiectasia
defect in DNA helicase RecQL3
predisposed to lymphoproliferative & GI malginancy
where does heriditary nonpolyposis colon cancer usu arise
microsatellite instability
mismatch repair defect
usu proximal bowel
waxing & waning lymphadenopathy
follicular lymphoma
bcl-2 t(14,18)
small cleave w/o nucleoli &
large cell w/ mult nucleoli
burkitt lymphoma in industrialized country location
ascites & abdominal mass
distal ileum, cecum, mesentary
Dupuytren’s contractures
fixed flexion of fingers
physical manifestation of high estrogen in cirrhotic patients
what are lisch nodules
pigmented iris hamartomas
what’s in a neurofibroma
schwann cells, fibroblasts, neurites
niacin mechanism
block hormone sensitive lipase –> reduce formation of VLDL and triglyerides
increases HDL
decrease TG
possible niacin side effects
prostaglandin mediated:
flushing, pruitis, headache
how many of the oocytes we are born w/ remain at puberty?
25%
of that, only 400 will be ovulated normally
rest = atesia
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
which antibiotics are teratogen (2)
aminoglycoside “a mean guy hit the baby” CN VIII toxicity
tetracycline: discolored teeth
which antiseizure drugs are teratogen (3)
carbamazepine, phenytoin, valproate (inhibit folate reabsporption
PVC
which anti-thyroid drug is a teratogen
methimazole
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
reason diff alleles have different cuts on restriction enzyme digestion?
single nucleotide polymorphisms at restriction enzyme cleavage site
how does paclitaxel in a drug-eluting stent work?
prevents intimal hyperplasia
major cause of restenosis
after placing a coronary stent, what is the major cause of restenosis?
intimal hyperplasia
prevent w/ paclitaxel / sirolimus
freeze cells in metaphase
anti-platelets post stent?
given LONGER w/ drug-eluting stents (paclitaxel) bc the rate of endolthelium reformation delayed.
less time w/ bare metal stents
which RNA viruses replicate in nucleus?
- retroviruses (HIV, HTLV)
- influenza
where does influenza replicate
nucleus! (+ HIV) all other rna virus = cytoplasm
most common cause of pneumonia in infant
RSV
croup & bronchiolitis in children
bronchitis in adult
parainfluenza birus
which GLUT is insulin dependent? which tissues
GLUT 4: muscle & adipocytes
what 2 muscles pull on acromial-end of clavicle? medial portion (3)
lateral:
- deltoid
- trapezius
medial
- pec major
- sternocleidomastoid
- sternohyoid
Ras is downstream
GTP-binding protein
downstream RTK
-single transmembrane, dimerize on binding
(not GPCRs)
differential of orotic aciduria?
- if also hyperammonia: OTC
build up of carbamoyl phosphate –> shunt to de novo pyridamine synthesis –> orotic acid temp base - w/o hyperammonia –> orotic aciduria
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
most common amino acid in collagen
glycine
Gly-X-Y (other: proline, lysine)
absence of proline hydroxylation results in
cannot form pro-collagen in ER bc triple-helix will be abnormal.
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
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
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
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)
conversion
conversion: symptoms unexplained by medical condition. preceeded by psychological stressor
not intentionally produced; cause impairment of normal fxn.
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
what neurological disease makes a protein w/ excess glutamine residues
huntington’s!
CAG repeats are translated –> polyglutamine
4 trinucleotide repeat diseases
- huntington
- myotonic dystrophy
- fragile X syndrome
- friedrich’s ataxia
confabulation
unintentionally fabricates memories that he believes to be true
wernicke-korsakoff vs. alzheimers & pseudodementia etc..
wernicke-korsakoff may also have ataxia (cerebellar degeneration)
alzheimers, pseudodementia, etc = NORMAL GAIT. more cortical / cognitive issues
normal pressure hydrocephalus vs. wernicke-korsakoff
both have gait problems
no confabulation in NPH
succinyl-CoA and glycine are starting products for..
heme synthesis
in mitochondria
via ALA synthase (w/ B6)
starting substrates for pyrimidine de novo synthesis
glutamine + CO2
also need aspartate + PRPP
from where are the nitrogen atoms in urea derivived from
ammonia & aspartate
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
fatigue, myalgia, muscle cramp, weakness over a week
hypokalemia!
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.
3 effects of angII
- direct Na+ retention
- aldosterone production
- vasoconstrition
HLA codes for
MHC class I and II antigen presentation
class I: HLA A, B, C class IIL HLA DP, DQ, DR
CD40-CD40L
CD40 on B cell
CD40L on T cell
needed for B cell activation: class switching
CD28-B27
CD28 on T cell
B27 on B cell
costimulatory molecule
w/ TCR & MHC interaction
w/o this: T cell -> anergy
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
chondrosarcoma on X-ray
bony destruction at tumor site
mechanical ventillation implies fixed (2)
- total minute ventilation (TV x RR)
- FiO2
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
with fixed ventillation, how can hypercapnea develop
increase in pathologic deadspace (i.e. diffusion barrier)
microsatellite instability
abnormal lengthening or shortening of macrosatellite repeats
related to HNPCC
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
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.
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.
gag codes for..
p24 capsid
env codes for ..
gp120 (attachment) gp 41 (fusion)
from cleavage of gp160
pol codes for..
reverse trancriptase, aspartate protease, integrase
mobile flank mass that produces a bruit
think: renal cell carcinoma!
which can obstruct IVC and cause ascities / peripheral edema
consider IVC obstruction in..
any patient w/ sudden lower extremity edema
