Isemura T

Micronuclei in human bone-marrow cells: Evaluation of the micronucleus test using human leukemia patients treated with antileukemic agents

The relevance of the micronucleus test to human studies was investigated by using bone marrow from leukemic patients treated with antileukemic drugs. The median incidence of micronucleated erythrocytes and erythroblasts, respectively, increased from control values of 0.04 and 0.72% to 0.29 and 25.3% in leukemic cases; and the frequency of micronucleated erythroblasts was inevitably higher than the control value in cases that showed a higher frequency of micronucleated erythrocytes, but the reverse was not true. These results indicate that almost the same changes of micronucleus formation that are observed in the mouse micronucleus test are produced in human bone marrow by antileukemic drugs--mutagenic compounds--and, if the micronuclei were scored restrictively in erythroblasts, the application of the micronucleus test to human bone marrow would be reasonable.

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

SummaryThe method of cytofluorometric measurement of the contents of Hb and nuclear DNA on a single erythroid cell (Fukuda et al., 1975, 1977 a) was used for the quantitative analysis of the erythropoiesis in normal human bone marrow.The intracellular Hb in an erythroid cell was converted to fluorescent porphyrin after removing the Giemsa staining 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 narrow 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 expulsion of a whole intact nucleus.