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Markers for colon carcinogenesis
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Information Section
than after pure air, and the number of subjects who suffered late asthmatic reactions was increased from seven to 10 (Strand V. et al., American Journal of Respiratory and Critical Care Medicine 1997, 155, 881).
Environmental oestrogens and reproductive function A preliminary US experiment has demonstrated that foetal exposure to bisphenol A in the dose range currently being consumed by people can affect the adult reproductive system in mice. Mice (seven per group) were fed 2 or 20 gg/kg body weight/day from days 11 to 17 of pregnancy. One male offspring per litter was then kept for 6 months, at which time prostate weight was determined. Prostate weight was increased at both doses. 4-Octylphenol at the same doses had no such effect (Nagel S.C. et aL, Environmental Health Pcnpectives 1997, 105, 70).
Mutagenic potential of an environmental pollutant The environmental pollutant, 2-nitrofluoranthene, which has previously been reported to be mutagenic in Salmonella typhimurium bacteria, has now been found to be even more powerfully mutagenic in a human cell line. The US investigators concluded that their results *support the concern that 2-nitrofluoranthene may be a risk to human health" (Busby W.F., Jr et aL, Mutation Research 1997, 389, 261).
The hazards of restraint In inhalation tests A few years ago there were reports of serious toxic effects in mice exposed to the volatile emissions of a number of consumer products, particularly from carpets. A recent US study indicates that the physical restraint of the animals in the original inhalation studies may have been the cause of the problem. Mice that were held in elastic neck collars for 1 hour, twice daily on two consecutive days suffered effects including weight loss, compression
damage to the liver and haemorrhaging in the pituitary gland. It was concluded that repeated exposure of mice in this way *may resuk in physical injuries and stress which may significantly affect any evaluation of toxicity and neurotoxicity in treated animals" (Stott W.T. et aL, Food and Chemical Toxicology 1997, 35, 241).
Markers for colon carcinogenesis Traditionally, changes in cell number (proliferation) have been used as a predictor of subsequent tumour formation. An experiment in which rats treated with a standard genotoxic colon carcinogen, azoxymethane, were given fish oil or cellulose in their diet (both of which are believed to exert a protective effect against colon carcinogenesis), has examined the link between the development of tumours, and cell differentiation and apoptosis (programmed cell death), as well as proliferation. It was found that differentiation and apoptosis were better predictors of diet-induced differences in colon tumorigenesis than was cell proliferation (Chang W.-C.L. et aL, Carcinogenesis 1997, 18, 721).
A new test for genotoxicity Investigators at the Flemish Institute for Technological Research have developed a new bacterial test, the VITOTOX test, which they claim provides a more sensitive way of detecting genotoxicity than the bacterial tests (the Ames test in Salmonella typhimurium and the SOS chromotest in Escherichia coh) currently favoured by the regulators. Molecular cloning techniques have been used to transfer specific genes from E. call to produce a more effective Salmonella system. Its main advantage was said to be that the kinetics of genotoxicity could be determined (as neither plating nor disruption of the cells is required to measure genotoxicity), and thus distinctions could often be made between compounds in genotoxic mixtures (van der Lelie D. et aL, Mutation Rew.arcb 1997, 389, 279).
Information Section
than after pure air, and the number of subjects who suffered late asthmatic reactions was increased from seven to 10 (Strand V. et al., American Journal of Respiratory and Critical Care Medicine 1997, 155, 881).
Environmental oestrogens and reproductive function A preliminary US experiment has demonstrated that foetal exposure to bisphenol A in the dose range currently being consumed by people can affect the adult reproductive system in mice. Mice (seven per group) were fed 2 or 20 gg/kg body weight/day from days 11 to 17 of pregnancy. One male offspring per litter was then kept for 6 months, at which time prostate weight was determined. Prostate weight was increased at both doses. 4-Octylphenol at the same doses had no such effect (Nagel S.C. et aL, Environmental Health Pcnpectives 1997, 105, 70).
Mutagenic potential of an environmental pollutant The environmental pollutant, 2-nitrofluoranthene, which has previously been reported to be mutagenic in Salmonella typhimurium bacteria, has now been found to be even more powerfully mutagenic in a human cell line. The US investigators concluded that their results *support the concern that 2-nitrofluoranthene may be a risk to human health" (Busby W.F., Jr et aL, Mutation Research 1997, 389, 261).
The hazards of restraint In inhalation tests A few years ago there were reports of serious toxic effects in mice exposed to the volatile emissions of a number of consumer products, particularly from carpets. A recent US study indicates that the physical restraint of the animals in the original inhalation studies may have been the cause of the problem. Mice that were held in elastic neck collars for 1 hour, twice daily on two consecutive days suffered effects including weight loss, compression
damage to the liver and haemorrhaging in the pituitary gland. It was concluded that repeated exposure of mice in this way *may resuk in physical injuries and stress which may significantly affect any evaluation of toxicity and neurotoxicity in treated animals" (Stott W.T. et aL, Food and Chemical Toxicology 1997, 35, 241).
Markers for colon carcinogenesis Traditionally, changes in cell number (proliferation) have been used as a predictor of subsequent tumour formation. An experiment in which rats treated with a standard genotoxic colon carcinogen, azoxymethane, were given fish oil or cellulose in their diet (both of which are believed to exert a protective effect against colon carcinogenesis), has examined the link between the development of tumours, and cell differentiation and apoptosis (programmed cell death), as well as proliferation. It was found that differentiation and apoptosis were better predictors of diet-induced differences in colon tumorigenesis than was cell proliferation (Chang W.-C.L. et aL, Carcinogenesis 1997, 18, 721).
A new test for genotoxicity Investigators at the Flemish Institute for Technological Research have developed a new bacterial test, the VITOTOX test, which they claim provides a more sensitive way of detecting genotoxicity than the bacterial tests (the Ames test in Salmonella typhimurium and the SOS chromotest in Escherichia coh) currently favoured by the regulators. Molecular cloning techniques have been used to transfer specific genes from E. call to produce a more effective Salmonella system. Its main advantage was said to be that the kinetics of genotoxicity could be determined (as neither plating nor disruption of the cells is required to measure genotoxicity), and thus distinctions could often be made between compounds in genotoxic mixtures (van der Lelie D. et aL, Mutation Rew.arcb 1997, 389, 279).