Rx_HemOnc_2.28

Question 1

SCID: presentation & common causes

Answer 1

• profound T & B lymphocyte immunodeficiencies ==> recurrent infections by viruses, protozoa, bacteria, fungus
• common causes
  
  • adenosine deaminase deficiency (AR)
    
    • ADA = necc. for purine nucleotide breakdown ==> build-up of deoxyadenosine triphosphate ==> toxic to rapidly proliferating cells (e.g. developing lymphs)
    • prone to Candida & PCP
  • IL-2 receptors (x-linked)

Question 2

Biostatistical parameters:

“ability of the test to rule out disease”

“ability of test to rule in disease”

Answer 2

• rule out = sensitivity
• rule in = specificty

Question 3

Order of locations of hematopoiesis during development

Answer 3

• fetal erythropoiesis =
  
  1. yolk sac (3-8 weeks)
  2. liver (6 mo.–birth)
• infant erythropoiesis =
  
  1. splean (10-28 weeks)
  2. bone marrow (18 weeks onward)

Question 4

EBV: virus type

Answer 4

linear, double-stranded DNA virus

Question 5

Active form of prednisone

Answer 5

• prednisone ==> prednisolone [active form] via 11-B-hydroxysteroid dehydrogenase

Question 6

(Neg.) nitroblue tetrazolium dye reduction ==> dx?

Answer 6

• Chronic Granulomatous Disease
  
  • due to deficiency of nicotinamide adenine dinucleotide phosphate oxidase (NADPH oxidase) ==> conversion of O₂ => superoxide radicals
• increased susceptibility to catalase (+) organisms
  
  • S. aureus
  • E. Coli
  • Aspergillus

Question 7

S. aureus appearance on gram-stain

Answer 7

gram (+) cocci in clusters

Question 8

Fibrinogen facilitation of platelet aggregation via…

Answer 8

• interaction w/ GP IIb/IIIa <== expressed on the surgace of platelets

Question 9

Abciximab: MOA, use

Answer 9

• monoclonal Ab binds to GP IIb/IIIa ==> prevention of platelet aggregation
• use
  
  • acute coronary syndrome
  • angioplasty
  • percutaneous coronary stent placement

Question 10

Clopidogrel (Plavix): MOA

Answer 10

• anti-platelet drug
• irreversibly blocks ADP receptor on platelets ==> decreased aggregation adn expression of GP IIb/IIIa

Question 11

Triclopidine: MOA

Answer 11

• anti-platelet drug
• irreversibly blocks the ADP receptor on platelets ==> decreased aggregation and the expression of GP IIb/IIIa

Question 12

TPA: MOA

Answer 12

• tissue plasminogen activator: enzyme that cleaves plasminogen to plasmin ==> breakdown of fibrin clots

Question 13

Physiology of CO poisoning

Answer 13

• CO binds to oxygen-binding sites on hemoglobin w/250x affinity of oxygen
• ==> decrease in oxygen-carrying capacity ==> left-shift of the oxy-hemoglobin curve

Question 14

G6PD deficiency ==>

Answer 14

• lower levels of the reduced form of NADPH
• G6PD = enzyme @ hexose monophosphate (HMP) shunt pathway
  
  • NADP+ ==> NADPH
  • NADPH ==> reduces glutathione w/help of glutathione reductase
  • reduced glutathione protects against oxidant injury
• oxidative stress ==> hemolytic anemia