The occupational physician's point of view: the model of man-made vitreous fibers.

Abstract

This article gives a detailed description of the procedure the occupational physician uses in interpreting the available scientific data to provide useful information for prevention of pulmonary diseases related to man-made mineral fibers, particularly lung cancer and mesothelioma. As it is difficult to reach definite conclusions from human data on the toxicity of specific fibers, an experimental approach is needed. Concerning animal data, we emphasize that adequate inhalation studies are the "gold standard" for extrapolating to humans. However, experiments using intracavitary injection or cells in vitro may represent indicative tests for a possible carcinogenic effect. Such tests should be used to assess the intrinsic carcinogenicity of fibers, but they must be confirmed by adequate inhalation models. Despite the present uncertainties, a proposal is made that could make it possible to classify fibers according to their toxicologic potential, grading them in accordance with physicochemical parameters, in vitro testing, and animal experiments. This procedure may be applicable to nonvitreous fibers and to organic fibers. -Environ Health Perspect 102(Suppl 5):31-36 (1994)

In Vitro Effects of Large and Small Glass Fibers on Rat Alveolar Macrophages

“…There remains a question, however, as to the relevance of in vitro testing versus in vivo inhalation exposures. As reviewed by Brochard et al (1994), a small excess of lung cancer has been noted in groups of workers exposed to some types of MMVF. The epidemiological study of human MMVF exposures is still very difficult, however.…”