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27 Cards in this Set

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What are Myeloperoxidases?
enzymes in neutrophils that utilize iron.
What are the physical characterists of RBCs in iron deficiency induced anemia?
microcytic hypochromatic… that is the cells are small and not colored… also decreased rate of hemoglobin synthesis.
What is the treatment of iron deficiency anemia?
Oral ferrous sulfate… also intravenous iron therapy or packed RBC transfusion
What is lactoferrin? What is the double benefit of this protein?
it is a Fe binding protein found in mother's milk for storage and transport, (b) nurishment and intimicrobial action.
How does lactoferrin help the neonate deal with gut bacteria?
it competes with the bacteria for the iron.
What are haptoglobins?
involved in capturing oxyhemoglobin dimmers Hb∂-Hbß… and prevents loss through kidney… it is also involved in the process where heme is separated from the globin.
What happens to Fe when the heme is converted to Fe (free), CO and Bilirubin?
Transferrin binds it for transport
None
Where are transferrin and haptoglobin made?
liver
What is the role of transferrin?
Transferrin binds free Fe so that it doesn't readily deposit into cells, rather when bound to transferrin, Fe will only enter cells as a function of receptor mediated transport (Tf receptors)
None
What is the function of Ferritin?
storage of Fe in tissues
What is ferritin used for in the clinical setting?
the small level found in the plasma allow for a measure of the total Fe content of our body stores.
What are 3 signs of iron deficiency?
(a) plasma ferritin = 0… (b) transferrin binding capacity upper limit is about 300 ub/dL… (c) Fe saturation for transferrin is <16%
What is an IRE?
it's nucleotide sequence on mRNA.
What is the role of IRE-BP with respect to ferritin?
It binds to IRE and inhibits translation of Ferritin (tissue storage) when [Fe] is low.
What happens to IRE-BP during high [Fe] with respect to ferritin?
it dissociates and allows translation of ferritin to accommodate influx of Fe.
What is the role of IRE-BP with respect to transferrin receptors?
It stabilizes transferin receptor mRNA during low [Fe]
What happens to IRE-BP during high [Fe] with respect to transferrin receptors?
In high [Fe] IRE-BP dissociates from the transferrin receptor mRNA and the mRNA strand degrades.
What is the locational difference between IRE-BP for transferrin and ferritin?
Ferritin is at the beging of the mRNA strand, while transferrin is at the end.
What is hemochromatosis? And what is the gene associated with this disorder?
Fe overload… HFE
What is mechanism of hemochromatosis?
it causes the increase in the amount of transferrin receptors made, and thus transferred into the cells.
What are symptoms of hemochromatosis?
bronze skin, cirrhosis of the liver and damage to the pancreas could lead to diabetes I, fatigue and arthalgia (painfull joints)… iron is toxic
How would you measure this diagnostically?
transferrin saturation levels would rise from 10-30% to 35-50%
How is it that free Fe are toxic? (Hint: Fenton Reaction)
Oxidized to from ferrous to ferric by H2O2 forming OH• (hydroxyl radical) , this radical can react with lipid and protein to damage tissues.
given that there are 1/300 afflicted with hemochromatosis, what is the frequency for carriers?
q^2= 1/300, thus,(1/300)^.5 = q… p=1-q… heterozygotes=2pq = .11 =11%
None
(a) Where is the HFE gene located? (b) And what does this mean in terms of it's function
(a)in the HLA-A3 region… (b) such that the region no longer functions in antigen presentation… it's too small… it now facilitates Fe transport
What is significant about losing a cysteine to a tyrosine in HFE muations?
the lack of a cystein makes the amino acid unable to form a dissulfide bond.
In terms of macrophages, what change of function does the HFE mutation cause?
uncontrolled release of Fe