Cutaneous melanoma in African-Americans.

Although cutaneous melanoma is rare in African-Americans, it continues to have a poor prognosis. We reviewed our experience with 13 African-American patients who had cutaneous melanoma diagnosed between 1969 and 1990. Eight of these 13 lesions were on the foot.

Enhancement of the responses of human colon adenocarcinoma cells to X-irradiation and cis-platinum by N-methylformamide (NMF).

The ability of the maturational agent N-methylformamide (NMF) to modify the response of exponentially growing clone A human colon adenocarcinoma cells to x-irradiation, cis-platinum (cis-DDP), or x-irradiation combined with cis-platinum was studied using an in vitro clonogenic assay. When clone A tumor cells were adaptively grown in medium containing 1% NMF (V/V) for 3 passages prior to experiments, a significantly increased sensitivity to x-irradiation as compared to non-NMF treated cells was found. This increased sensitivity was most marked in the low dose region of the survival curve (as indicated by a large increase in the alpha constant in the linear-quadratic equation), and is similar to the increased radiosensitivity observed after treatment of these tumor cells with N,N-dimethylformamide (DMF).

In vitro sublethal damage repair in tumour subpopulations from a heterogeneous human colon tumour.

The repair of sublethal radiation damage in two asynchronously growing tumour cell subpopulations (clones A and D) obtained from a single human adenocarcinoma biopsy specimen has been studied. The survival data found after generation of complete survival curves from split dose experiments in which exposures were separated by 3, 6, 12, or 24 h were examined. It was found that the method of performing irradiations (e.