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DIT 2009 WK 9
Q&A from DIT emailed questions WK 9
Question | Answer |
---|---|
How can a surgical lesion of the subthalamic nucleus might help improve the symptoms of Parkinson’s? | Inhibitory pathway: Substantia nigra pars compacta’s dopamine binds to D2 receptors in the inhibitory pathway, inhibiting the inhibitory pathway (increasing motion) |
MOA propylthiouracil? | Inhibits organification and coupling of thyroid hormone synthesis, also decreases peripheral conversion of T4 to T3 |
Side effects of propylthiouracil? | Skin rash, agranulocytosis (rare), and aplastic anemia |
Phase of hepatic metabolism lost first by geriatric pts? | Phase I |
Phase of hepatic metabolism mediated by cytochrome p450 | Phase I |
Reactions involved in Phase I hepatic metabolism? | HOR - Hydrolysis, Oxidation, Reduction |
Substance that inhibits the conversion of dopamine to norepinephrine? | Reserpine |
Substance that inhibits the reuptake of choline by a presynaptic cholinergic neuron? | Hemicholinium |
What is an illusion? | misinterpretations of actual external stimuli |
What is a delusion? | false beliefs not shared w/ other members of culture/subculture that are firmly maintained in spite of obvious proof of the contrary |
What is a hallucination? | perceptions in the absence of external stimuli |
Enzyme deficient in alkaptonuria? | Homogentistic acid oxidase |
Manifestations of alkaptonuria? | Dark connective tissue, pigmented sclera, urine turns black on standing “Long history of pain and stiffness” |
What enzyme catalyzes the rate-limiting step in cholesterol synthesis? | HMG-CoA reductase |
What class of drugs inhibits this enzyme? | Statins (Lovastatin) |
Toxic side effects of phenytoin? | Nystagmus, ataxia, diplopia, sedation, SLE-like syndrome, induction of cP-450. Chronic use produces gingival hyperplasia in children, peripheral neuropathy, hirsutism, megaloblastic anemia (dec folate absorption). Teratogenic (fetal hydantoin syndrome) |
Valve most commonly involved in bacterial endocarditis? | Mitral valve |
Valve most commonly involved in acute rheumatic fever? | Mital valve |
On which cells would you expect to find MHC I? | On almost all nucleated cells |
On which cells would you expect to find MHC II? | Only on antigen-presenting cells |
How can neurotoxicity be prevented in pts receiving isoniazid (INH)? | Give Vit B6 (Pyridoxine) |
What are the signs of portal hypertension? | Esophageal varices, melena, splenomegaly, caput medusa, ascites, hemorrhoids |
What are the signs of liver failure? | coma, sclera icterus, fetor hepaticus (corpse breath), spider nevi, gynecomastia, jaundice, testicular atrophy, liver “flap” (asterixis), bleeding tendency, anemia, ankle edema, decreased lipids & platelets |
What is type I (alpha) error? | A false positive error, will show that something “is” when it really “isn’t” |
Give the neurotransmitter levels in Schizophrenia | Inc dopamine |
Give the neurotransmitter levels in Parkinson's | Dec dopamine, Inc ACh |
Give the neurotransmitter levels in Alzheimer's | Dec ACh |
Give the neurotransmitter levels in Hungtington's | Dec GABA, Dec ACh |
Give the neurotransmitter levels in Anxiety | Inc NE, Dec GABA, Dec serotonin (5-HT) |
Give the neurotransmitter levels in Depression | Dec NE, Dec Serotonin (5-HT), Dec dopamine |
Actions of angiotensin II? | On vascular SM for Inc BP, Constricts efferent a., stimulates aldosterone release, Na/K pump in principal cells for h2O reabsorption, Stimulates ADH release from post pituitary, inc proximal tubule Na/H activity, stimulates thirst from hypothalamus |
What is variable expression? | Phenotypic severity varies b/w patients with the same mutation |
What is incomplete penetrance? | Not everyone w/ a mutant genotype will show the mutant phenotype (skips generations) |
What is pleiotropy? | Single genetic defect resulting in multiple phenotypic effects |
What is anticipation? | Severity of disease worsens or the age of onset is earlier in succeeding generations (assc. w/ trinucleotide repeats) |
Which protozoa are responsible for Chaga's disease? | Tryanosoma cruzi (Reduviid bug, Dx: blood smear, Rx: Nifurtimox) |
Which protozoa are responsible for amoebic dysentery? | Entamoeba histolytica (bloody diarrhea, liver abscess, dx: serology and/or Trophozoites or cysts in stool; Trophozoites with phagocytosed RBC’s, rx: Metro and iodoquinol) |
Which protozoa are responsible for protozoal vaginitis? | Trichonomas v. (foul-smelling, yellow-greenish discharge, alkaline, strawberry cervix, Dx: Trophozoites motile on wet mount, treat sexual partner as well) |
Which protozoa are responsible for malaria? | Plasmodium (Cyclic fever, headache, anemia, splenomegaly, Anopheles) |
Which protozoa are responsible for spiking fevers, hepatosplenomegaly, pnacytopenia? | Leishmania donovani (painful boils, Sandfly, Dx Macrophages with amastigotes, Rx Sodium stibogluconate & Ampho B) |
Which protozoa are responsible for bloating, flatulence, foul-smelling diarrhea in campers and hikers? | Giardia |
What structures can be found in the cavernous sinus? | CN III, IV, V1, V2, & VI and postganglionic sympathetic fivers en route to the orbit |
What teratogen causes cervical clear cell adenocarcinoma? | Diethylstilbestrol |
Which teratogen (previously administered for morning sickness) causes limb defects? | Thilidomide |
Structures that form Hesselbach’s triangle? | Inferior epigastric artery, Lateral border of rectus abdominis, & Inguinal ligament |
Type of hernia that protrudes through Hesselbach’s triangle? | Direct inguinal hernia |
Most common tumor of the urinary tract? | Transitional cell carcinoma |
What is the usual presenting complaint of a pt with transitional cell carcinoma? | Painless hematuria is suggestive of bladder cancer, can occur in renal calyses, renal pelvis, ureters, and bladder |
What substance exposures increase the risk of developing transitional cell carcinoma? | Phenacetin, Smoking, Aniline dyes, and Cyclophosphamide (Rx w/ Mesna) |