title: Repair of potentially lethal damage after single injection or continuous infusion of bleomycin.
abstract: The repair of potentially lethal damage after administration of bleomycin by a single injection or by continuous infusion was studied in vivo. Experimental tumors were the fifth generation isotransplants of a squamous cell carcinoma which arose spontaneously in a C3Hf/He female mouse. Bleomycin was administered intraperitoneally by a single injection or by 24-hr continuous infusion. Cell survival was assayed by TD50 method. Dose-survival curve after a single injection exhibited a biphasic or upward concave curve. Surviving fraction increased rapidly if tumors were left in situ after treatment and reached a plateau at 5 hr, indicating that tumor cells were able to repair the potentially lethal damage induced by bleomycin. Dose-survival curve after continuous infusion was also biphasic, but had a small shoulder. The repair of potentially lethal damage was slight, if any, when tumors remained in situ for 6 hr after the end of 24-hr continuous infusion. This indicates that potentially lethal damage was being repaired during drug infusion.
mesh_terms: D000818:Animals; D001761:Bleomycin / Q000008:administration & dosage*; D002294:Carcinoma, Squamous Cell / Q000188:drug therapy*; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005260:Female; D007263:Infusions, Parenteral; D007274:Injections, Intraperitoneal; D008297:Male; D051379:Mice; D009368:Neoplasm Transplantation; D009374:Neoplasms, Experimental / Q000188:drug therapy; D014185:Transplantation, Isogeneic
chemical_list: D001761:Bleomycin