A board Q - hunanliu

[ArchivalUser]

What is the switch mechanism from HbF to HbA after the birth?

[ArchivalUser]

An erythropoietic activity that exerts a profound effect on fetal Hb synthesis is present in fetal sheep sera and it attains a peak concentration at the end of the second to the middle of the third trimester of fetal life. The activity consistently inhibits the increased synthesis of fetal Hb in cultures of burst-forming units (BFUes) from normal adults. In cultures of BFUes from homozygous ß +-thalassemias the activity produces a striking decline in chain synthesis, a decline in G /A chain synthesis ratio, and an increase in / and / non- ratios--i.e., findings suggesting a genuine -to-ß switch. The activity accelerates Hb F-to-Hb A switching in neonatal BFUe cultures but it has no effect on fetal Hb synthesis in cultures of BFUe obtained from human fetuses. These findings provide direct evidence that (a) humoral factors play a role in the regulation of the switch from fetal to adult Hb formation, and (b) progenitor cells from various stages of ontogeny respond differently to these factors. The results are compatible with the hypothesis that Hb switching during development is mediated through a change in a developmental program which controls the responsiveness of progenitor cells to ``switching'' activities in their environment.

[ArchivalUser]

here is some more,also imp is inducing hbf in thalassemia,sickle cell anaemia as a treatment modality.

http://64.233.179.104/search?q=cache:LcC...=clnk&cd=3

[ArchivalUser]

I think what I wrote about treatment is still in research.

[ArchivalUser]

okay,they are using hydroxyurea;since it has lot of side effects they are searching for more safer drug.why because desoxyferroxamine the drug used in these cases,is not enough to keep the iron load low.also I got know that there are 2 swiches total.