@misc{ParodiLutzColaccietal.1989, author = {Parodi, S. and Lutz, Werner K. and Colacci, A. and Mazzullo, M. and Taningher, M. and Grilli, S.}, title = {Results of animal studies suggest a nonlinear dose-response relationship for benzene effects}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-60843}, year = {1989}, abstract = {Considering the very large industrial usage of benzene, studies in risk assessment aimed at the evaluation of carcinogenic risk at low Ievels of exposure are important. Animal data can offer indications about what could happen in humans and provide more diverse information than epidemiological data with respect to doseresponse consideration. We have considered experiments investigating metabolism, short·term genotoxicity tests, DNA adduct formation, and carcinogenicity long-term tests. According to the different experiments, a Saturation of benzene metabolism and benzene effects in terms of genotoxicity seems evident above 30 to 100 ppm. Below 30 to 60 ppm the initiating effect ofbenzene seems tobe linear fora large intervaJ ofdosages, at least judging from DNA adduct formation. Potentiallack of a promoting effect of benzene (below 10 ppm) could generate a sublinear response at nontox.ic levels of ex.posure. This possibility was suggested by epidemiological data in humans and is not confirmed or excluded by our observations with animals.}, subject = {Toxikologie}, language = {en} } @article{GrilliLutzParodi1987, author = {Grilli, S. and Lutz, Werner K. and Parodi, S.}, title = {Possible implications from results of animal studies in human risk estimations for benzene: nonlinear dose-response relationship due to saturation of metabolism}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-60936}, year = {1987}, abstract = {To date, all risk assessment studies on benzene have been based almost exclusively on epiderniological data. Wehave attempted a more integrated and quantitative evaluation of carcinogenic risk for hurnans, trying to utilize, in addition to the epidemiological data, all data available, specifically data on metabolism, genotoxicity, and carcinogenicity in small rodents. An integrated evaluation of the globality of the available data seems to suggest a progressive saturation of metabolic capacity both for man and rodents between 10 and 100 ppm. The most susceptible target cells seem tobe different in humans (predominant induction of myelogenous leukemia) and small rodents (induction of a wide variety of tumors). Nevertheless, both epidemiological and experimental carcinogenicity data tend to indicate a flattening ofthe response for the highest dosages, again suggesting a general Saturation of mechanisms of metabolic activation, extended to different target tissues. From a quantitative point of view, the data suggest a carcinogenic potency at 10 ppm two to three times higher than that computable by a linear extrapolation from data in the 100 ppm range. These observations are in accord with the recent proposal of the European Economic Community of reducing benzene time-weighted average occupationallevels from 10 to 5 ppm.}, subject = {Toxikologie}, language = {en} }