Correlation of radioactive hemin formation with morphologic alterations in cultures of human bone marrow.

I N A PRECEDING PAPER a method was presented for observing maturation of human erythroblasts in a clot-free cell suspension culture system in vitro.’ The parameter of maturation was the increase of orthochromic cells (luring the period of incubation. The present study was undertaken to determine the extent to which the morphologic parameter of maturation correlated with a basic aspect of erythroblast maturation, namely, the formation of hemoglobin. For this purpose the measurement of radioactive heme formation in the presence of radioactive glycine was selected, because it represented an easily identiflable portlon of the whole hemoglobin molecule.