Genotoxicity of waste anaesthetic gases.

BACKGROUND AND AIM: The possibility of a potential mutagenic or carcinogenic action of chronic exposure to low concentrations of inhalational anaesthetics has been previously studied, with conflicting results. The purpose of this study was to assess whether occupational exposure to waste anaesthetic gases increases genotoxic risk. We examined peripheral lymphocytes from anaesthetists for both sister chromatid exchange (SCE) and for cells with high-frequency SCEs (HFCs). METHOD: A group of 16 non-smoking anaesthetists with occupational exposure to anaesthetic gases and a sex- and age-matched group matched 16 non-smoking matched physicians without occupational exposure to anaesthetic gases were studied. The participants were also selected on the basis of similar responses to a questionnaire assessing risk of genotoxicity relating to other aspects of life. RESULT: SCEs, and HFC percentages obtained from the exposed anaesthetists (6.6+/-2.4 and 12.2+/-15.9) were greater but not statistically significantly so than in the reference group (5.2+/-1.6 and 5.9+/-10.0). CONCLUSION: This study does not support the existence of an association between occupational exposure to waste anaesthetic gases and an increase in SCEs in lymphocytes. The nature of our anaesthesia practice suggests exposure was likely to be low. It should be noted that some anaesthetic gases produce lesions that can be efficiently repaired in mitogen-stimulated lymphocytes in vitro but not in circulating lymphocytes.

Human tumor cell identification in short-term cultures by combined microdensitometry and autoradiography.

Several groups are using short-term cultures of human tumor specimens as models to study cancer. When cells from a biopsy are grown in this way, it is essential to confirm that the tumor cells and not the normal stromal cells have been cultured. This paper reports the use of combined microdensitometry and autoradiography to identify tumor cells in cultures prepared from different types of malignancy, especially abdominal tumors, melanomas and gliomas. Cells of known origin were analyzed to provide standards. Three main results were shown. (1) Provided that the tumor cells have DNA values which differ from normal by at least 10%, they can be identified when the cells are first put into culture, and their presence can be confirmed at later stages. (2) The proportion of normal and tumor cells can be estimated, and the presence of just 10% normal cells can be detected, so new culture methods designed to favor the growth of tumor cells can be evaluated. (3) Most types of tumor are suitable for analysis, but when biopsies contain a high proportion of stromal fibroblasts, there is a real danger that after about 20 days in culture the normal cells will overgrow the tumor cells. An attempt to distinguish tumor cells which have normal DNA values from normal cells on the basis of a different optimum hydrolysis time with hydrochloric acid was unsuccessful.