Interaction of Ionizing Radiation and 8-Methoxypsoralen Photosensitization: Some Implications for Risk Assessment
Much effort, including the greater part of the present Workshop, is devoted to consideration of the likely consequences of human exposure to low concentrations or fluences of single genotoxic agents. Yet humans do not live in a one-toxin environment. A multitude of mutagens and promoters are ingested, inhaled, or generated endogenously as an obligatory component of everyday life, and we know they cannot be ignored. There are those who would draw attention to the existence of detoxifying pathways and repair systems which might be induced by this abundance of everyday mutagens, so that any dose of a single additional agent would encounter these systems at high levels of activity. Low doses of the additional agents might then be rapidly removed or the damage repaired, resulting in an effective threshold or quasi-threshold. Others would have us focus on the error-prone pathways and metabolic activation systems that might be induced, or detoxification pathways and repair pathways that might be saturated by ambient exposure to mutagens. A small dose of an additional mutagen might then cause more damage than expected.
KeywordsSkin Cancer Skin Tumor Tinea Capitis Beta Radiation Beta Particle
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