[Examination of the effects of hyperthermia and anticancer agent on cultured human gall bladder cancer cells by DNA fluorimetric assay].

Tumor cells are generally more sensitive to hyperthermia than normal cells. We applied hyperthermia for bile duct cancer therapy. We also studied the effect of hyperthermia and anticancer agents using cultured cancer cells. In this study, we examined the effect of hyperthermia and adriamycin by using newly established cultured human gall bladder cancer cells. In order to calculate cell numbers, we used the new DNA fluorimetric assay with fluorochrome dye Hoechst 33342, developed by Richards et al. For the purpose of confirming the usefulness of this fluorimetric assay, we compared this assay with methylene blue and 3H-thymidine incorporation methods. The following results were obtained: 1) the combination effect of hyperthermia and adriamycin showed an additive effect, 2) the effect of hyperthermia was only intensified according to the extension of heating time, but the combination treatment resulted in a maximum effect at the early stage of heating, 3) DNA fluorimetric assay with Hoechst 33342 dye was a sensitive, easy and rapid method for calculating cell numbers compared with methylene blue and 3H-thymidine incorporation methods, and more useful for studies of cultured cells.