Micronuclei assay in cytokinesis-blocked binucleated and conventional mononucleated methods in human peripheral lymphocytes.

Studies were performed to determine the genotoxic effect of cytochalasin-B (CYB) and to compare the efficacy of the cytokinesis-blocked binucleated cells (CB) for scoring micronuclei (MN) with the conventional mononuclear method, following treatment with mitomycin C and cyclophosphamide. The results show that 3-4 micrograms/ml of CYB induced maximum number of binucleated cells without any genotoxic effect and the frequency of MN in binucleated cells was higher than that in the mononucleated cells (P less than 0.05) but less than twofold. However, MN frequencies in binucleated cells were not equivalent to the frequencies of mononucleated cells, since MN in binucleated cells represent two nuclei. These results suggest that further study is required to consider CB method as a more reliable approach for scoring MN.