UWorld SA - 6/3/2014

Question 1

What electrolyte distrubance can adversely affect renal concentrating ability and produce polyuria, polydipsia and dilute urine

Answer 1

Hypercalcemia. Pathophysiology is similar to nephrogenic DI

Question 2

Gp2b/3a is a surface receptor on platelets that bind to ? And belong to the family of ?

Answer 2

Fibirnogen and integrins. Drugs like Abciximab, eptifibatide are 2a/3b antagonists

Question 3

How does the heart respond to exercise?

Answer 3

Increased CO = SV * HR. Increased HR via 1) decreased vagal stimulation 2)increased sympathetic stimulation. Increased SV by !) increased preload and 2) decreased afterload via decreased peripheral vascular resistance due to vasodilation in muscles. This allows heart to empty more completely leading to decreased ESV. End Diastolic pressure is relatively UNCHANGED because the increased cardiac output cancels the hypotensive effect of the vasodilation in the muscles.

Question 4

In LV systolic dysfunction, ESV and EDVs?

Answer 4

Both increased

Question 5

In LV diastolic dysfunction, ESV and EDVs?

Answer 5

Both decreased

Question 6

Kayser Fleischer rings are deposits in what part of the eye

Answer 6

Cornea. Typically occur in patients with neuro involvment (dysphagia, dysarthria, tremor)

Question 7

Dysplastic nevus - histology.Due to what mutation? A/w with what cancer

Answer 7

nests of nevomelanocytes with hyperchromatic nuclei with bridging nests. Due to mutation of 9p21 chromosome. Associated with melanoma.

Question 8

What is the regional specification of the developing brain? What are the mnemonics to help remember this?

Answer 8

THREE PRIMARY VESICLES: PMR - PROSENCEPHALON, MESENCEPHALON, RHOMBENCEPHALON // FIVE SECONDARY VESICLES: TD Makes Money Matter. Prosencephalon becomes 1) Telencephalon (cerebral hemispheres and lateral ventricles) 2) Diencephalon (thalamus and third ventricle), Mesencephalon remains mesencephalon (no change change - becauses midbrain and acqueduct) and Rhombencephalon becomes 1) metencephalon (pons and cerebellum, upper part of the fourth ventricle and) 2) myelencephalon becomes 1) medulla and lower part of fourth ventricle

Question 9

What are examples of DNA binding proteins?

Answer 9

helix-loop-helix, and zn finger motifs, basic zipper proteins that contain leucin ( short 30 amina acid alpha helical protein with leucine residues every 7 aa. These are part of a zipper dimeriazation found in basic zipper proteins. transcription factors that bind to DNA)

Question 10

KNOW WHAT REED STERNBERG CELLS LOOK LIKE

Answer 10

Owl eye appearance. Usually found on lymph node aspirates but can also be found in bone in advanced Hodgkins lymphoma.

Question 11

FOR CRYING OUT LOUD DON’T SCREW UP RIFAMPIN VS INH

Answer 11

RIFAMPIN: Inhibits bacterial DNA dependent RNA polymerase => inhibits transcription. Subsequent lack of mRNA leads to deficiency of these proteins necessary for mycobacterial survival. Altered rifampin binding site/altered DNA dependent RNA polymerase. INH - INHIBITS mycolic acid synthesis

Question 12

What is the ppt of a choriocarcinoma?

Answer 12

Presents during pregnancy or after deliver in mom or baby. Malignancy of trophoblasts *both cytotrophoblasts and syncytiotrophoblasts). There are NO chorinoic villi. Elevated bHCG, shortness of breath, vaginal bleeding, hematogenous spread to lungs. responsive to chemo. commonly associated with molar pregnancy

Question 13

What is MOA for dihydropyridine calcium channel blockers? Why is it useful in angina?

Answer 13

Works especially on arteriole smooth muscle in the peripheral vasculature vs. myocardium. Causes vasodilation, decreases afterload and the work that the heart has to do to pump blood (less o2 consumption which is what we want for angina)

Question 14

What is Von Gierke’s disease? Inheritance? PPT? Food to avoid?

Answer 14

Glycogen storage disease type 1. A/R. Deficiency of glucose 6 phosphatase which is needed for gluconeogenesis and glycogenolysis. Avoid both fructose and galactase. Increase oral glucose in diet. Ppt: severe hypoglycemia, hepatomegaly, lactic acidosis and hyperuricemia

Question 15

What is Pompe disease? Inheritance? PPT?

Answer 15

Glycogen storage disease type 2. A/R. Due to defiency in alpha-1,4-glucosidase (acid maltase) which constitutively breaks down glycogen. This is a LYSOSOMAL enzyme. Deficiency => glyocgen build up in lysosomes => PAS positive granules. PPT: massive cardiac hypertrophy and muscular weakness. can lead to early death

Question 16

Klinefelter presentation

Answer 16

small testes, gynecomastia, euchoid body shape. Low serum testosterone (hyalinzed seminiferous tubules), elevated LH and estradiol

Question 17

in DIC - levels of 1) fibrinogen 2) PTT 3) PT 4) Platelets

Answer 17

1) decreased 2) increased 3) increased 4) decreased. Psosibly shistocytes due to MAHA

Question 18

What is alkaptonuria?

Answer 18

AKA ochronosis. A/R. Deficiency in homogentisate oxidase which is necessary in the degradation of tyrosine/Phe to fumarate. Results in the accumulation of homogentisate in cartilage (ears),sclera dermis and skin and also excreted in urine/sweat. Homogentisate is toxic to cartilage and may cause bad arthralgias

Question 19

Remember there is a difference between fungal cell WALL AND MEMBRANE.

Answer 19

CELL WALL drugs - echinocandina. CELL MEMBRANE drugs - amphotericin B, Nystatins, Azoles (inhibit synthesis of ergosteral)

Question 20

Kaposi sarcoma can occur AT ANY STAGE OF HIV INFECTION

Answer 20

most common malignancy in HIV patients. Vascular malignancy from HHV8

Question 21

Nonsense vs missense mutation

Answer 21

Nonsense - point mutations resulting in the formation of a premature stop codon. Missense mutation - substitution of one amino acid for another

Question 22

Where are carbamoyl phosphate synthetatase II and I located? What are their substrates?

Answer 22

Carbamoyl phosphate sythetase II catalyzes glutamine + Co2+ 2ATP to form carbamoyl phosphate in de nove pyrimidine synthesis that starts in the CYTOSOL. Ammonia + CO2 combine in the mitochondria, catazlyed by carbamoyl phosphate synthetase I.

Question 23

Primary hyperparathyroidism symptoms?

Answer 23

stones, bones, groans and psychiatric overtones

Question 24

Examples of nuclear receptors

Answer 24

Vit A, Vit D and steroids

Question 25

Reiter syndrome is ppted by?

Answer 25

Urogenital (chlamydia) or gi infections (Salmonella, shigella, campy, or Yersinia). Cutaneous lesions like keratoderma blenorrhagica are also common