Cytofluorometric analysis of cell proliferation and differentiation of the human erythroblasts.

The method of cytofluorometric measurement of the contents of Hb and nuclear DNA on a single erythroid cell (Fukuda et al., l975; 1977a) was used for the quantitative analysis of the erythropoiesis in normal bone marrow. The intracellular Hb in an erythroid cell was converted to fluorescent porphyrin after removing the Giemsa staning by irradiation with violet light in the presence of SH-donor (mercaptoethylamine hydrochloride, MEA) and its nuclear DNA was subsequently stained with pararosaniline Feulgen staining. With the two quantitative parameters, Hb content and DNA amount, the erythroid cells in normal human bone marrow were classified into 6 classes of different maturation stages (EI-EIV). The morphological characteristics of the most primitive erythroblast (EI cells) were described. The "proerythroblasts" which were identified on the bases of morphological criteria had in general aneuploid amounts of nuclear DNA with disproportional contents of Hb, thereby indicating that they are rather aberrations from the normal steps of cell maturation. The DNA amounts of "orthochromatic erythroblasts" (EV cells) showed continuous decrease from diploid range to almost zero suggesting that the removal of nuclear DNA from the erythroblast is not exclusively due to mechanical explusion of a whole intact nucleus.