Combined use of bleomycin in radiotherapy of a mouse mammary carcinoma.
Experiments were carried out to determine TCD50 (50% tumor control dose) of 3rd generation isotransplants of a C3H mouse mammary carcinoma treated or not treated with Bleomycin. If the antibiotic was injected 30 min before a single X-ray dose, TCD50 was reduced. This reduction in TCD50 was independent of Bleomycin dose of more than 15 mg/kg, because of the upward-concave nature of Bleomycin dose-cell survival curve. The combined effect, when tested by TCD50 assays, appeared less than additive. This effect was further examined by a series of TD50 assays which revealed that these tumor cells were capable of repairing the potentially lethal damage induced by X-rays and that induced by Bleomycin. It was also found that the potentially lethal damage after combined X-ray and Bleomycin treatments was repaired. These findings indicated that the combined X-ray and Bleomycin treatment resulted in additive effect if the repair of potentially lethal damage in tumor cells were taken into account.
D000818:Animals; D001761:Bleomycin / Q000008:administration & dosage / Q000627:therapeutic use*; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004307:Dose-Response Relationship, Radiation; D005260:Female; D008325:Mammary Neoplasms, Experimental / Q000188:drug therapy / Q000532:radiotherapy / Q000628:therapy*; D051379:Mice; D008809:Mice, Inbred C3H; D011879:Radiotherapy Dosage; D013997:Time Factors; D014965:X-Rays
D001761:Bleomycin