title: Work in progress: the effect of heat on bleomycin cytotoxicity in vitro and on the accumulation of 57Co-bleomycin in heat-treated rat tumors.
abstract: The cytotoxic effects of the sequence and timing in combined hyperthermia and bleomycin treatment were tested in vitro using V79 Chinese hamster cells. The order of treatment was important; heat treatment followed by the administration of bleomycin yielded greater cytotoxicity than when the opposite order was used. To determine whether heat-treated tumors have an altered uptake of bleomycin, rat rhabdomyosarcoma (BA 1112) tumors were heated locally with RF current (43 degrees C, 90 min.), injected with 57Co-bleomycin, and imaged on a radioisotope camera. Results of tumor-to-background (T/B) ratio analysis indicate that (a) local hyperthermia (43 degrees C) does not appear to alter tumor uptake patterns of 57Co-bleomycin; and (b) intravenous and intraperitoneal injections produce similar T/B uptake ratios, typically between 2 and 3 at 120 minutes postinjection. In the BA 1112/WAG/Rij tumor system, local hyperthermia treatment does not seem to interfere with the subsequent accumulation of bleomycin in the tumor.
mesh_terms: D000818:Animals; D001761:Bleomycin / Q000378:metabolism / Q000494:pharmacology / Q000627:therapeutic use*; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D003037:Cobalt Radioisotopes; D006224:Cricetinae; D003412:Cricetulus; D006358:Hot Temperature; D009374:Neoplasms, Experimental / Q000188:drug therapy / Q000378:metabolism; D051381:Rats; D012208:Rhabdomyosarcoma / Q000188:drug therapy* / Q000378:metabolism
chemical_list: D003037:Cobalt Radioisotopes; D001761:Bleomycin