[Flow-microfluorometric studies on the effect of misonidazole as a radiosensitizer for human uterine cervical carcinoma transplanted to nude mice].

It is already known that Misonidazole as a radiosensitizer is not so effective with the small doses of radiation that we generally use to treat human uterine cervical carcinoma by fractionated irradiation. Using nude mice in which human uterine cervical carcinoma was transplanted, we examined DNA distribution by Flow-Microfluorometry, nuclear area and growth curves with 1,000 rads single dose irradiation, equally fractionated irradiation (250 rads/day for 4 days) and unequally fractionated irradiation (250 rads/day for 4 days, 500 rads for 1 day) after administration of Misonidazole. It was recognized that repopulation was delayed with 1,000 rads single dose irradiation with Misonidazole 1 mg/g.b.w. since a reduction in the rate of increase in G2-M cells and an increase in debris lasted a long time in DNA distribution, and the tumor regrowth time was delayed when compared to the only irradiation group. These changes were not observed with equally fractionated irradiation with Misonidazole 0.25 mg/g.b.w/day administration, but were significantly observed with unequally fractionated irradiation with Misonidazole 1 mg/g.b.w. at 500 rads irradiation where the nuclear area was also reduced. As mentioned above, it can be considered that the clinical effect of Misonidazole can be expected as in the case of unequally fractionated irradiation.