[Combined effects of cis-DDP and OK-432 on ascitic mastocytoma in mice: optimal period for the administration of OK-432].

Combined effects of cis-DDP and OK-432 on the ascites mastocytoma was studied in mice laying emphasis on the best timing for the administration of the OK-432. Mice were transplanted with FMA3 mastocytoma cells into the abdominal cavity at a dose of 10(5) cells per mouse. They were injected with cis-DDP next day at a single shot of 8 mg/kg in the abdominal cavity. A streptococcal preparation, OK-432, was i.p. injected two times at intervals of one week at a dose of 50 KE/kg per injection. The pair of injections started 1, 2, 3, 4 or 5 weeks after the transplantation. Mean survival time (M. S. T.) of mice was 16.8, 16.2 and 52.3 in the groups of mice nontreated, given OK-432 alone, and given cis-DDP alone, respectively. In comparison of M. S. T. within the groups of mice treated with the combination of cis-DDP and OK-432, the highest value was observed in the group which was given OK-432 between 3 and 4 weeks after the transplantation.