Study on enhancement of tumor-killing effect and formation of new fluorophore in tumor cells.

Hyperthermia (42-44 degrees C) and photosensitizing therapy can destroy S180 tumor cells, reduce malignant ascites and prolong the survival times of mice with carcinomas. The highest curative effect was observed when using a combination of the two treatments. Heating to 44 degrees C has a greater destructive effect on tumor cells than has heating to 42 degrees C. The results show that this is due to a synergistic interaction between these two treatments. The fluorescence spectrum of S180 cells was determined before and after treatment, and the indication was that the synergistic effect is probably related to a new fluorescence product; the greater the intensity of the new fluorescence, the more marked the synergy of hyperthermia and photosensitizing therapy. The maximum emission wavelength was 460nm (excitation wavelength 370nm).