[PDF] Strategies For Short Term Testing For Mutagens Carcinogens eBook

Author : K.H. Norpoth
Publisher : Springer Science & Business Media
Page : 424 pages
File Size : 20,91 MB
Release : 2012-12-06
Category : Medical
ISBN : 3642672027

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The varying cancer incidence from country to country and region to region suggests that en vironmental factors play a considerable role in the aetiology of cancer. Whether these factors in the environment moderate the effect of car cinogenic chemicals or whether they might them selves be carcinogenic is not known at the present time. What is known is that there are various chemicals, both naturally occurring and man-made, which can induce cancer in man. In the Western world estimates vary as to how much cancer is occupational in origin; the figures range from 1% to 40%. It is our feeling that probably about 10% of cancer has a direct oc cupational origin. Nevertheless this number is considerable and it behoves us therefore to identify those chemicals which are carcinogenic and to reduce human exposure. Recent work on the mode of action of carcinogenic chemicals suggests that the majority exert their effect through an activation step to give elec trophilic metabolites. Such metabolites have as a common feature the ability to react with cel lular nucleophiles to give covalently bound products. Such reaction will occur after carcino gen treatment of animals with nucleic acids par ticularly in target organs. It is reaction with nucleic acids that provides the basis of a num ber of short-term tests for carcinogens, since the basic composition of DNA is similar in micro-organisms and in human cells.

Author : H.F. Stich
Publisher : Springer
Page : 518 pages
File Size : 50,42 MB
Release : 2011-10-08
Category : Medical
ISBN : 9781461258490

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The recent surge of interest in designing, validating, and implementing short-term tests for carcinogens has been spurred by the fairly convincing correlation be tween the carcinogenicity and mutagenicity of chemicals and physical agents and by the assumption that DNA alteration, mutations, and chromosome aberrations are somehow involved in neoplastic transformation. Moreover, it has been tacitly assumed that the mutagenic capacity alone of compounds would induce regulatory agencies to pass rules for their removal from the environment and would lead the public to avoid them. The actual response, however, is quite different. Governmental departments shy away from making any decisions on the basis of in vitro test systems. The public at large is becoming irritated by daily an nouncements that many of their cherished habits could adversely affect their health. Industry appears to feel threatened and may reduce its search for new beneficial chemicals. The reluctance to accept wholeheartedly the mutagenicity tests for the detection of carcinogens is partly due to uncertainty about the in volvement of mutations in neoplastic transformation, partly due to the present difficulty of extrapolating results from various endpoints obtained on numerous organisms to man, and partly due to a multitude of complex events that lead in vivo to the evolvement of benign or malignant tumors.