Heme/Onc

Question 1

what is carboxyhemoglobin

Answer 1

CO-bound to hemoglobin

Question 2

What is methemoglobin

Answer 2

formed with Fe2+ (ferrous iron) is oxidized to Fe3+ (ferric iron)

Question 3

Causes of anemia of chronic disease

Answer 3

Malignancy
Chronic infection
rheumatic disease
Obesity
DM
Congestive HF
(disease that last a long time)

Question 4

Anemia of chronic disease path

Answer 4

increase in inflammatory cytokines (hepcidin)

Question 5

What is hepcidin

Answer 5

inflammatory cytokine
Decrease iron absorption
Increase iron sequestration
Reduced circulating iron-> impaired erythropoiesis

Question 6

What are CD55 and CD59

Answer 6

CD55: Decay-accelerating factor
CD59: Mac inhibitory protein

Question 7

What is paroxysmal nocturnal hemoglobinuria (PNH)

Answer 7

Mutation in PIGA gene
Absent GPI anchor->CD55 and CD59 deficiency->complement mediated hemolysis

Question 8

GPI anchors to

Answer 8

CD55 and CD59 on RBC membrane
Absence of CD55 and CD59 allows MACs to form->hemolysis

Question 9

What inactivates 6-mercaptopurine

Answer 9

Xanthine oxidase

Question 10

6-mercaptopurine MOA

Answer 10

Converted by HGPRT into 6-thioguanine (6-TG) which mimic nucleotides and disrupt DNA and RNA synthesis

Question 11

What is azothioprine

Answer 11

Azothioprine -> 6-mercaptopruine -> 6-TG active metabolites
Mimic nucleotides-> disrupt DNA, RNA

Question 12

What causes schistocytes

Answer 12

Microangiopathic hemolytic anemia (HUS, TTP, DIC)
or
Mechanical Trauma (prosthetic valve, calcified valve)