Effect of azelaic acid on melanoma cells in culture.

Using a clonogenic assay in vitro, it has been shown that exposure to azelaic acid (1-100 mM) for 24 hours has a dose-dependent effect on the survival of the colony-forming ability of murine (B16) and human (HMB2, and SK23) melanoma cells as compared with a non-melanotic non-tumoral Chinese hamster cell line (CHO). Both human cell lines were more sensitive to the diacid than the murine cells, and the HMB2 cells were more sensitive than the SK23 cells. These differences may be partly correlated with differences in pigmentation and doubling times between the three melanoma cell lines.

The effect of paraquat on the radiosensitivity of melanoma cells: the role of superoxide dismutase & catalase.

The activities of reactive oxygen species scavenging enzymes, superoxide dismutases (SODs) and catalase (in cells of two melanomas (mouse B16 and human SK23) and in Chinese hamster ovary (CHO) cells were examined. Melanoma cells are relatively depleted in activities of superoxide dismutases and catalase as compared to CHO cells. Short equitoxic (500 microM for CHO and B16 cells and 5 microM for SK23 cells) paraquat treatment (15 min before the X-irradiation, 45 min in postirradiation period--the total time of treatment was 1 h) caused an increase in radiation resistance, measured as colony forming ability, in two of the three lines examined.

The optimum pressure of oxygen for radiotherapy of a mouse tumour.

Our previous studies have shown that there is more regrowth delay in mammary tumours irradiated in C3H mice after 25 Gy when breathing normobaric oxygen than in those breathing air, as might be expected. However, in both cases this radiation response was reduced in anaesthetized animals in comparison with unanaesthetized control mice, when a time interval of only 10 min was allowed after anaesthesia. After 25 min, however, the response in air returned to the control level and the oxygen group now showed significantly more radiosensitization.

Rate of metastasis from C3H mouse mammary tumours.

Transplants from the same C3H mouse mammary tumour have been used for radiobiological experiments with curative intent for more than 8 years. During that time, the rate of metastasis to the lungs has varied between 0 and 63% and an explanation has been sought for this change. The results of immunological assays showed no obvious pattern.