ASSESSMENT OF 2 PROTOCOLS FOR THE HUMAN LYMPHOCYTE CYTOKINESIS-BLOCKED MICRONUCLEUS ASSAY

This study indicated that by adding cytochalasin B (6 mu g/ml) at 24 h , the lymphocyte culture time for micronucleus (MN) assay could be sho rtened to 64 h. In both unirradiated and ex-vivo irradiated (2 Gy) lym phocytes from three populations, we found that the differences in MN y ield obtained by our modified cytokinesis-blocked time frame and that recommended by Fenech and Morley (1985) were insignificant (P = 0.66-0 .87). We believe that the shorter assay time may enhance the applicabi lity of MN assay for the rapid assessment of ionizing radiation overex posures.