Marianne I Willems

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This report provides guidance for using the dose-descriptor T25 from animal studies as a basis for quantitative risk characterisation of non-threshold carcinogens. T25 is presently used within the European Union for setting specific concentration limits for carcinogens in relation to labelling of preparations (formulations). The T25 is defined as the(More)
The effect of consumption of Brussels sprouts on levels of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) in human urine was investigated in 10 healthy, male, non-smoking volunteers. Following a 3 week run-in period, five volunteers continued on a diet free of cruciferous vegetables for a subsequent 3 week intervention period (control group), while the other(More)
The relative sensitivity of various methods suitable for monitoring the exposure to genotoxicants was studied in rats treated orally by gavage with benzo[a]pyrene (BP). The results were related to the occurrence of DNA adducts in liver. Male Wistar rats were treated once by gavage, BP doses ranging from 1 to 200 mg/kg body wt. The monitoring methods applied(More)
It is generally recognized that human, epidemiological data, if available, are preferred as the starting point for quantitative risk analysis above the use of data from animal studies. Although methods to obtain proper risk estimates from epidemiological data are available, several impediments prevent their widespread application. These impediments include(More)
The influence of lead on sperm morphology, sister chromatid exchanges or on micronuclei formation was studied on male rabbits after exposure to doses of 0, 0.25, and 0.50 mg lead acetate/kg body weight subcutaneously injected three times a week during 14 weeks, each on a group of five rabbits. At the end of exposure phase the lead in blood concentrations of(More)
A subchronic oral toxicity study with potassium nitrite (KNO2) was carried out in rats. Groups of ten male and ten female 6-wk-old rats received KNO2 in the drinking-water (tap-water) at levels of 0, 100, 300, 1000 and 3000 mg/litre for a period of 13 wk. The potassium concentration in the nitrite solutions was equalized by adding potassium chloride (KCl)(More)
of papers Abstracts of the posters 'Photobiological effects of 5-nitrofurfural in bacterial testsystems and irreversible photobinding' by R.W. Busker and G.M.J. Beijersbergen van Henegouwen, 'Photoproducts from chloramphenicol and their possible role in bone marrow toxicity', by H. de Vries, G.M.J. Beijersbergen van Henegouwen and H.C.G.M. Nooijens, and(More)
It has been shown that the spontaneous revertants in the Ames test can depend on the amount and type of bottom agar on the plates. The most clear-cut effect was found with the his G46 strains, carrying the delta uvrB mutation, and with the new hisG428 strain, TA102. Evidence of mutagenic impurities in agar has been found.