uworld assessment block #3 4.15 Flashcards
genetic pulmonary hypertension? demographic?
inactivating mutation in BMPR2. normally inhibits smooth muscle proliferation.
uterine leoimyomas presentation? demographic?
some asymptomatic. others: pelvic pressure, pain, menorrhagia, reproductive difficulties.
more common in women in thirties and forties. black women esp.
ischemic colitis
mucosal hemorrhage, patchy areas of necrosis.
eventually becomes edematous and bowel wall thickens. then transmural infarction –> bowel perforation.
crampy abdominal pain, tenderness to palpation, bloody stool.
caused by (1) hypoperfusion 2nd to diministed cardiac output (2) occulusion of bowel vascular supply (atheroma, thrombosis, embolism)
common cause of GI hemorrhage in elderly.
presentation of whipple’s disease
PAS+ foamy macrophages in lamina propria
CANN: cardiac symptoms (valves), arthalgia (synovial), mesenteric Nodes, and Neurologic symptoms (CNS).
–> fat malabsorption // steatorrhea bc of occlusion of lymphatics
nfxn w/ tropheryma whipplei (gram positive)
type 1 collagen important in
bone, fibrous tissue, tendon, ligament, skin, sclerae.
body is 30% collagen by weight
mutations in osteogenesis imperfecta
COL1A1 and COL1A2. both combine to form type 1 collagen –> results in qualitative and quantitative type I collagen defects
brittle bone, short stature, scoliosis, blue sclerae (translucent CT over choroidal veins), hearing loss (abnormal ossicles), skin and ligament laxity, easy bruising.
blue sclerae seen in..
osteogenesis imperfecta, progeria, menkes syndrome, cutis laxa
general beta oxidation & ketone production
sequential removal of two-carbon units (acetyl-CoA) from fatty acids
first step. Acyl CoA dehydrogenase. when a lot of acetyl-CoA is made via beta oxidation, shunt to ketone body production (acetoacetate, 3-hydroxybutyate, acetone)
3 forms of acyl CoA dehydrogenase
short, medium, long-chain
most common genetic defect in beta oxidation
medium chain acyl CoA dehydrogenase deficiency. symptoms first few years of life w/ prolonged fasting.
see increased dicarboxylic acids [from omega oxidation]. low glucose & ketones. acetyl-CoA low, cannot stimulate pyruvate carboxylase in gluconeogenesis. low acetyl-CoA, low glucose.
[energy from beta oxidation needed for gluconeogenesis!]
glycogen phosphorylase
cleave alpha-1,4-glycosidic link between glycogen, liberates glucose-1-phosphate.
results in McArdles, when missing from muscle.
results in Hers disease, when missing from liver.
Ras
oncoprotein component of MAP-kinase. inactive-GDP bound. active-GTP bound.
brings signal from receptor of cell surface into nucleus – promote mitogenesis.
c-myc
nuclear phosphoprotein. fxns as a transcription activator controlling cell proliferation, differentiation, and apoptosis.
Rb
nuclear phosphoprotein, regulates G1-S checkpoint.
velocity of a chemical reaction depends on.. (3)
concentration of enzyme, substrate, and product
increasing enzyme concentration
increases Vmax.
Km unchanged.
lower Y intercept on lineweaver-burke plot
increased Km on lineweaver burke plot
right on x-intercept (-1/Km)
what do chlamydia have INSTEAD of cell wall
cysteine-rick out membrane w/ S-S bridges
hyphae are..
multicellular branching filaments
fungi genome
diploid (eukaryotes)
four rRNA in eukaryotic cells
28S, 18S, 5.8S, 5S.
first: 45S transcript made by rRNA (pre-RNA) and cleaved in nucleolus by ribonucleases to make 28S, 18S, 5.8S rRNA molecules.
(ensures equal amounts are made)
5S rRNA made separately by RNA pol III
note additive, based on molecule size and how they move during centrifugation in a viscous medium.
how do thiazolidinediones increase insulin sensitivity
PPar gamma.
increase GLUT4 expression, increases number of insulin-responsible adipocytes.
glyburide
second generation sulfonyurea. closes K+ channel of pancreatic B cell, induces depolarization and L-type Ca2+ opening; stimulating insulin release.
repaglinide
meglitinide dervative: short-acting insulinotropic agent. adjunct to diet & exercise in DM-2. mechanism similar to sulfonyureas.
unlike sulfonyureas, repaglinide does NOT stimulate insulin release when extracellular glucose levels are lw