UWorld_1.20

Question 1

Most common benign tumor of breast =

Answer 1

fibroadenoma

Question 2

breast biopsy, dx?

Answer 2

fibroadenoma

Question 3

child w/severe intellectual disability + seizures + pallor @ substantia nigra, locus ceruleus, vagal nucleus dorsalis ==> dx/

Answer 3

PKU (phenulketonuria)

Question 4

mechanism of PKU

Answer 4

• lack of phenylalanine hydroxylase or tetrahydrobiopterin (BH4) [it’s cofactor] ==> buildup of phenylalanine @ body fluids and CNS

Question 5

colchicine: MOA/use/SE

Answer 5

• inhibition of microtubular polymerization ==> prevention of aggregration ==> disrupts chemotaxis and phagocytosis
• also inhibits formation of leukotriene B4
• use = acute gouty arthritis
• SE = nausea, abdominal pain, diarrhea

Question 6

Common colonization location of staph aureus

Answer 6

nasal colonization

Question 7

Microscopic steps of inflammation

Answer 7

• margination
• rolling
• activation
• tight adhesion and crawling
• transmigration

Question 8

Key molecular components of rolling

Answer 8

• loose binding via sialyated carbohydrate groups
• @ PMNs = L-selection
• @ endothelial cells = E-selectin/P-selectin

Question 9

Key molecular components of tight adhesion and crawling

Answer 9

• CD18 beta 2 integrins (Mac-1 and LFA-1) bind to ICAMs on endothelial cells

Question 10

Key molecular components of transmigration

Answer 10

• PMNs squeeze between cells and out of vasculature
• migrate via integrin attachments and adherence to platelet endothelial cell adhesion molecule 1 (PECAM-1)

Question 11

Middle meningeal artery is a branch of the…?

Answer 11

maxillary artery

Question 12

Presentation of tuberous sclerosis

Answer 12

• bilateral renal angiomyolipomas
• cortical tubers
• subependymal hamartomas @ brain
• cardiac rhabdomyoma
• facial angiofibroma
• leaf-shaped patches of skin lacking pigment (ash-leaf patch)
• autosomal dominant condition

Question 13

When is K permeability highest during AP?

Answer 13

during repolarization phase

Question 14

Calculation of filtration fraction

Answer 14

• FF = (glomerular filtration rate)/(renal plasma flow)
  
  • renal plasma flow = (1-Hct)(Renal blood flow)

Question 15

Amino acids w/3 titrable protons (==> 3 pKas on titration curve)

Answer 15

• Histadine
• Arginine
• Lysine
• Aspartic acid
• glutamic acid
• cysteine
• tyrosine

Question 16

Enoxaparin: MOA

Answer 16

• low molecular weight heparin
• MOA: binding and activating antithrombin III
  
  • active ATIII prevents factor Xa from: prothrombin ==> thrombin
• ==> anticoagulant effect

Question 17

Characteristics of mastocytosis

Answer 17

• abnormal proliferation of mast cells
• ==> increased histamine secretion
• ==> increased gastric acid production by parietal cells of stomach

Question 18

Sensitivity =

Specificity =

Answer 18

Sens = TP/(TP + FN)

Spec = TN/(TN + FP)

Question 19

Digoxin clearance

Answer 19

via kidneys

Question 20

Glucorticoids stimulate…?

Answer 20

liver (gluconeogenesis/glycogenolysis)