USMLE Step 1 - uWorld High Yield Notes

USMLE Step 1 - uWorld High Yield Notes What are the two major microtubular motor proteins? Which does anterograde axonal transport, which does retrograde axonal transport? - Kinesin, Dynein Kinesin: Anterograde Dynein: Retrograde` What do you think, immunologically speaking, when you see someone with recurrent Neisseria infections? - Inability to form the membrane attack (MAC) complex this is a common complement deficiency What is the defect in Chronic Granulomatous disease? What is the pathophysiology? - NADPH Oxidase deficiency leads to the inability to kill intracellular organisms Characteristic triad of ataxia telangiectasia? - cerebellar ataxia, telangiectasias, increased risk of sinopulmonary infections What is the major immune deficiency of ataxia telangiectasia? - IgA deficiency, which predisposes to infections of the upper and lower airways (and other mucous membranes) There's a useful mnemonic for Ataxia Telangiectasia and the gene that's mutated. What is it? - ATM Ataxia Telangiectasia Mutated ATM gene is responsible for DNA break repair What is one reason that lead intoxication causes hypochromic anemia? - Mitochondrial iron transport is important for Heme synthesis! It's inhibited by lead. So you don't make heme in your mitochondria and you get hypochromic anemia. What is the biochemical problem in Lesch-Nyhan syndrome? (And, only if you got that right, what are the really cool symptoms of it?) - Defective purine catabolism, so buildup of purines. It's an X-linked recessive disorder with mutated HGPRT gene (hypoxanthine-guanine phosphoribosyltransferase, if you want to impress people). Now, if you got HGPRT and purine catabolism right, you can say: self-mutilating behavior on top of mental retardation, choreoathetoid (think Chorea) movements and spasticity. What is the defect in Niemann-Pick disease? What causes that? What is the common macular finding? - Sphingolipid degradation is defective Caused by an autosomal recessive defect in sphingomyelinase Cherry Spot on the macula? Niemann Pick's or Tay Sach's. If a baby gets exposed to an unclean knife (...) and subsequently develops rigid paralysis, what is the diagnosis, where do we think this might happen, and how do we prevent it? - Neonatal Tetanus Developing Countries Maternal immunization with tetanus toxoid is the best way to prevent it an adeuately immunized mom will transfer IgG's across the placenta to the neonate Which microtubule associated protein aids in anterograde transport of intracellular vesicles and organelles? Which end of the microtubule do they go towards? - Kinesin. Towards the (+) rapidly growing end. What is an early BRAIN finding of Ataxia-Telangiectasia and how does it manifest itself? - Cerebellar atrophy manifests as ataxia in the first years of life. High yield path association for Alzheimer's disease?