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27 Cards in this Set
- Front
- Back
- 3rd side (hint)
What are Myeloperoxidases?
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enzymes in neutrophils that utilize iron.
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What are the physical characterists of RBCs in iron deficiency induced anemia?
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microcytic hypochromatic… that is the cells are small and not colored… also decreased rate of hemoglobin synthesis.
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What is the treatment of iron deficiency anemia?
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Oral ferrous sulfate… also intravenous iron therapy or packed RBC transfusion
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What is lactoferrin? What is the double benefit of this protein?
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it is a Fe binding protein found in mother's milk for storage and transport, (b) nurishment and intimicrobial action.
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How does lactoferrin help the neonate deal with gut bacteria?
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it competes with the bacteria for the iron.
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What are haptoglobins?
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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.
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What happens to Fe when the heme is converted to Fe (free), CO and Bilirubin?
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Transferrin binds it for transport
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None
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Where are transferrin and haptoglobin made?
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liver
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What is the role of transferrin?
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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)
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None
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What is the function of Ferritin?
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storage of Fe in tissues
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What is ferritin used for in the clinical setting?
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the small level found in the plasma allow for a measure of the total Fe content of our body stores.
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What are 3 signs of iron deficiency?
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(a) plasma ferritin = 0… (b) transferrin binding capacity upper limit is about 300 ub/dL… (c) Fe saturation for transferrin is <16%
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What is an IRE?
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it's nucleotide sequence on mRNA.
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What is the role of IRE-BP with respect to ferritin?
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It binds to IRE and inhibits translation of Ferritin (tissue storage) when [Fe] is low.
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What happens to IRE-BP during high [Fe] with respect to ferritin?
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it dissociates and allows translation of ferritin to accommodate influx of Fe.
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What is the role of IRE-BP with respect to transferrin receptors?
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It stabilizes transferin receptor mRNA during low [Fe]
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What happens to IRE-BP during high [Fe] with respect to transferrin receptors?
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In high [Fe] IRE-BP dissociates from the transferrin receptor mRNA and the mRNA strand degrades.
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What is the locational difference between IRE-BP for transferrin and ferritin?
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Ferritin is at the beging of the mRNA strand, while transferrin is at the end.
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What is hemochromatosis? And what is the gene associated with this disorder?
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Fe overload… HFE
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What is mechanism of hemochromatosis?
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it causes the increase in the amount of transferrin receptors made, and thus transferred into the cells.
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What are symptoms of hemochromatosis?
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bronze skin, cirrhosis of the liver and damage to the pancreas could lead to diabetes I, fatigue and arthalgia (painfull joints)… iron is toxic
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How would you measure this diagnostically?
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transferrin saturation levels would rise from 10-30% to 35-50%
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How is it that free Fe are toxic? (Hint: Fenton Reaction)
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Oxidized to from ferrous to ferric by H2O2 forming OH• (hydroxyl radical) , this radical can react with lipid and protein to damage tissues.
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given that there are 1/300 afflicted with hemochromatosis, what is the frequency for carriers?
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q^2= 1/300, thus,(1/300)^.5 = q… p=1-q… heterozygotes=2pq = .11 =11%
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None
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(a) Where is the HFE gene located? (b) And what does this mean in terms of it's function
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(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
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What is significant about losing a cysteine to a tyrosine in HFE muations?
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the lack of a cystein makes the amino acid unable to form a dissulfide bond.
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In terms of macrophages, what change of function does the HFE mutation cause?
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uncontrolled release of Fe
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