2015.04.08 Flashcards
(29 cards)
Linkage disequilibrium
two allele loci are in linkage disequilibrium when a pair of alleles are inherited together in the same gamete more ore less often than would be expected given random chance.
Can occur even if genes are on different chromosomes.
Contralateral homonymous hemianopia with macular sparing
Lesions of occipital cortex (eg, posterior cerebral artery occlusion)
When are alpha-fetoprotein levels changed?
Elevated: multiple gestation, neural tube defects (spina bifida, anencephaly), abdominal wall defects (omphalocele).
Lowered: Down syndrome.
Junctional Complex
- Tight junctions (zonula occludens) at apices of glandular cells and consist of 2 closely adherent cytoplasmic membranes without an intervening space.
- Intermediate junctions (zonula adherens) are a delicate network of cytoplasmic filaments that radiate from the cell membrane to hold adjacent cells together.
- Desmosomes are samll, circular, adherent patches circumferentially placed around cells.
Non-polar, hydrophobic amino acids
Valine, alanine, isoleucine, methionine, phenylalanine
Aspiration of hydatid cysts
Inadvisable since the spilling of cyst contents within peritoneum can cause anaphylactic shock.
Surgery and chemotherapy (mebendazole or albendazole) is treatment of choice.
Superior orbital fissure
CN III, V1 branches (nasociliary branch), CN VI, and superior ophthalmic vein enter the orbit via this fissure.
Organophosphate poisoning
irreversibily inhibit cholinesterase in both muscarinic and nicotinic cholinergic synapses.
Pralidoxime is the only medication that reverses both muscarinic and nicotinic effects by “restoring” cholinesterase from its bond with organophosphates.
Atropine reverses muscarinic effects.
Hawthorne Effect (Observer Effect)
Tendency of study subjects to change their behavior as a result of their awareness that they are being studied.
Berkson’s bias
selection bias created by choosing hospitalized patients as the control group
Pygmalion effect
Researcher’s beliefs in the efficacy of treatment can potentially affect the outcome.
Screening vs. Diagnosing Treponema pallidum
RPR or VDRL are for screening. Patient’s serum is mixed with solution of cardiolipin, cholesterol and lecithin to detect presence of anti-cardiolipin in patients serum.
Confirmation: FTA-ABS. Detects antibodies directed against Treponema though indirect IF.
Wolff-Parkinson-White Syndrome
Accessory AV conduction pathway that can manifeset clinically as recurrent paroxysmal supraventricular tachycardia.
ECG shows triad of abnormalities corresponding to ventricular pre-excitation: shortened PR-interval, delta wave at start of QRS complex, and widened QRS interval.
Inulin vs. PAH
Inulin is filtered only - estimates GFR
PAH is filtered and secreted - estimates RPF
Leydig cells
Produce testosterone in response to stimulation by luteinizing hormone (LH). LH is released from the anterior pituitary in response to GnRH from the hypothalamus.
Through a negative feedback, testosterone inhibits both LH and GnRH release.
Analogous to female thecal cells.
Sertoli Cells
Produce inhibin in response to FSH from the anterior pituitary. Inhibin suppresses FSH production by the anterior pituitary, but does not feedback on the hypothalamus.
Main spermatogenesis, secrete Mullerian inhibiting factor during male embryogenesis.
Analagous to female granulosa cells.
Antiphospholipid Antibody Syndrome
30% of patients with SLE (glomerulonephritis, photosensitive skin rash, arthralgias in young woman) have antiphosopholipid antibodies.
Venous or arterial thromboembolic disease - DVT, PE, IS/TIA
Adverse pregnancy outcomes - unexplained fetal loss, premature birth due to placental insufficiency or preeclampsia.
Labs: Lupus anticoagulant effect; paradoxical aPTT prolongation. Presence of anticardiolpin and beta-2-glycoprotein-I antibody.
MEN type 2B
Medullary carcinoma of thyroid (calcitonin), pheochromocytoma, Marfanoid habitus/Mucosal neuromas.
MEN 1
Parathyroid tumor (hypercalcemia)
Pancreatic tumor (gastrin)
Pituitary adenoma (prolactin, ACTH)
Wilson’s Disease
cystic degeneration of the putamen as well as other basal ganglia structures.
RBCs filled with multiple, smaller round nucleated cells suggests?
Plasmodia (malaria) infection.
Erythrocytic forms of this paracyte can be treated with: Chloroquine or mefloquine.
Primaquine is required for P. vivax and P. ovale liver schizonts.
K excretion/reabsorption
K depletion stimulates alpha-intercalated cells to reabsorb extra potassium.
Principle cells secrete K under condtions of normal or increased K load.
Entacapone vs. Tolcapone
COMT inhibitors
Entacapone - inhibits peripheral methylation.
Tolcapone - inhibits both peripheral and central methylation. Associated with hepatotoxicity.
Arnold-Chiari malformation
Congential disease due to underdevelopment of the posterior fossa.
Causes cerebellum and medulla to hermiate through the foramen magnum.
Type I: low-lying cerebellar tonsils extend below the foramen magnum into the vertebral canal. Headaches and cerebellar symptoms.
Type II: compression of medulla - difficulty swallowing, dysphonia, stridor, and apnea. Severe and evident in newborn.
