Testing for carcinogens with rodents

Article Abstract:

Substances are evaluated for carcinogenicity (potential for causing cancer) according to scientific protocols that involve the administration of large doses to rodents for their lifetimes, and then extrapolating the results to humans. This approach is being criticized; meanwhile, a frightened public demands the cleaning-up of hazards that may not be nearly as dangerous as other hazards which may not have even been recognized. Although most chemicals are not mutagens (capable of causing genetic mutation), many produce cancer under current testing paradigms. Many chemicals that are naturally present in food also have a high rate of carcinogenicity; their concentration in food is much higher than that of man-made pesticides. Plants contain chemicals that can exert damaging effects on predators; cabbage, for instance, contains 49 'natural pesticides'. We consume approximately 10,000 times more natural pesticides than synthetic ones. An argument by Bruce Ames, a scientist who investigates carcinogenicity, points out that any agent that causes cells to divide more frequently opens the way to an increased mutation rate. This is because dividing cells are more vulnerable to mutation. Chemicals in rodent experiments are given at the maximum tolerated dose (MTD), which invariably increases the mutation rate. Lower doses, which would not have this effect, would not be likely to cause cancer (unless the substance were truly carcinogenic). Fruit and vegetable diets are known to be associated with reduced cancer risk; results from MTD studies that show these substances to be carcinogenic are therefore misleading. A 'new toxicology' needs to be developed, using modern analytic methods. (Consumer Summary produced by Reliance Medical Information, Inc.)

Health aspects, Models, Usage, Evaluation, Rodents, Carcinogenesis, Pesticides, Animal models in research, Animal research models, editorial

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Chairman of the House Science Committee

Article Abstract:

Walker's objectives will greatly affect the future role of the government in science issues. He has advocated space research, a manned space station and a risk-assessment bill. He also wrote a philosophical essay on finding hope amid revolutions in economics, politics, culture and technology.

Political aspects, Science and technology policy, Science and state, Science policy, Powers and duties, United States. Congress. House. Committee on Science, Walker, Robert S.

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A changing electric power industry

Article Abstract:

The electric power industry is developing regional power systems and using new technology to meet the needs of scientists and other users of sensitive electronic devices requiring completely reliable power supply. Efforts to lower the cost of electricity are also changing the industry.

Management, Innovations, Electric utilities, Prices and rates, Electric power, Interconnected electric utility systems, Interconnected electric power systems

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