Binucleate cell formation after fast neutron and alpha-particle irradiation

Binucleate cell formations after neutron and alpha-particle irradiation were investigated, and the results were comparatively studied with those of X-irradiation. Mouse mammary carcinoma cells FM3A exponentially growing in suspension culture were exposed to 14 MeV neutrons of the T (d, n) reaction or alpha-particles from 241Am. The cells exposed were fixed in Carnoy's solution, then stained with acetic-orcein solution, and the binucleate cells were counted. The percent of binucleate cells was at a maximum on the third day after irradiation when the rate of proliferation was at a minimum. By comparing the present data with those obtained by X-irradiation, the patterns of change in percent of binucleate cells after neutron and alpha-particle irradiation were very similar to those of X-rays. However, at equal cell killing rates, the percent of binucleate cells after neutron irradiation was smaller than that of X-irradiation, and that of alpha-particle irradiation was the least. (author)