[Consideration of simultaneous combination chemotherapy--employing a sensitivity test in Dunn osteosarcoma and NR fibrosarcoma by intra-test tube contact of tumor cell suspension, and subcutaneous inoculation].

Fundamental concepts of combination multi-drug chemotherapy have not been well recognized from the aspects of chemo-sensitivity test upon malignant tumors. A chemo-sensitivity test by in-vitro bioassay for Dunn osteosarcoma and NR fibrosarcoma was developed by us to study the simultaneous interactions between two anticancerous agents. 0.1 ml of cell suspension of either mouse sarcoma was immersed in 0.4 ml of RPMI 1640 cell culture medium containing an anticancerous agent such as Mitomycin (MC), Cyclophosphamide (CPM), Vincristine (VC), Bleomycin (BM), 5-FU, Adriamycin (ADM), Cisplatin (CDDP) or Methotrexate (MTX) in a test-tube, and incubated at 37 degrees C for 3 or 6 hours. Then, the sedimented cell suspension of 0.1 ml was inoculated subcutaneously in the dorsum of C3H mouse which provided 4 sites for 4 different sensitivity tests. In 3 weeks, sensitivities of the anticancerous agents were evaluated as positive sensitivity if no growth of the tumor was observed, or negative sensitivity if the growth of more than 10 mm in diameter was observed. Then, the determination of antitumorous effect on 2-drug combination out of the 8 anticancerous agents, were performed on each mouse sarcoma by the same method. In Dunn osteosarcoma or NR fibrosarcoma, the combination of 2 sensitivity-positive agents revealed no apparent synergistic effects. In any combinations of one sensitivity-positive agent with the other sensitivity-negative agent, except the combinations with CPM which possessed mighty antitumorous effect, apparent reduction of antitumorous effects was observed. The combination of 2 sensitivity-negative agents never produced any antitumorous effects.(ABSTRACT TRUNCATED AT 250 WORDS)