The acute response of the rat lung to a range of fibrous materials has been investigated by bronchopulmonary lavage, at dose levels of 0.5 and 1.0 mg, 1 and 7 days after their administration by intratracheal instillation. The materials chosen for study included UICC chrysotile A, amosite, crocidolite and anthophyllite, and samples of S. African "long" amosite and glass fiber. In addition, the s...

Lung burden analysis was performed on 126 autopsy cases of persons who died in New York City from 1966 through 1968. Of the 126 cases, 107 were probably non-occupationally exposed, judging by occupational history and asbestos body content of lung. Fifty-three of the 107 cases contained short chrysotile fibers/fibrils, < 5 microns in length, present in 3-fold greater amounts than were found in l...

Less than ten years ago, the asbestos industry enjoyed the support of every Quebec and Canadian political party. The Chrysotile Institute and the International Chrysotile Association, both located in Quebec, aggressively marketed asbestos around the world, claiming scientific evidence showed that chrysotile asbestos could be safely used. The industry created a climate of intimidation. Consequen...

This commentary challenges a recently published perception that Dr. Le Roy Upson Gardner had not actually discovered in 1942 that inhaled chrysotile fibers could induce malignant neoplasia in mice. The handwritten laboratory notes and some of Dr. Gardner's slides have recently been found. They verify that the tumors he saw in the mice included truly malignant neoplasms. Gardner had by then also...

Alveolar macrophages (AM) from bovine lungs were exposed in culture to manual metal are (MMA) welding fume particles, chromium (Cr), UICC chrysotile A or anatase for 17-20 hr. All the welding particle samples were more cytotoxic to AM than to anatase. Particles from the welding of mild steel with a rutile-coated electrode were less cytotoxic than those produced with a basic-coated electrode. Pa...

Two groups of 48 rats of the AF/HAN strain were exposed for one year to respirable dust clouds of UICC chrysotile asbestos at a dose level of 10 mg/m3. One group was treated with dust carrying the normal electrostatic charge produced during dust generation, whereas the other was exposed to dust discharged by exposure to ionising radiation from a thallium-204 source. After dusting most animals w...

The effects of chrysotile on DNA synthesis in the gastrointestinal tract of the rat were studied by measuring the uptake of tritium-labeled thymidine; whole stomach, small intestine, colon liver were removed, cleaned, and homogenized and the DNA was isolated and assayed for tritium label.A dose-response study indicated that 2 weeks after a 5 mg/kg dose of chrysotile, DNA synthesis was increased...

A study was made of 93 cases of mesothelioma who died in 1976 in the United Kingdom. Lung tissue was available for mineral fibre analysis from 86 of these cases, and also from 29 cases of cerebrovascular disease and 27 cases of bronchial carcinoma, matched for place of death, age and sex with the mesothelioma cases. It was observed that: (1) mesothelioma patients had more amphibole fibres in th...

Asbestos induces a constellation of biological responses in cells of the respiratory tract that are similar to those of classical tumor promoters. In this regard, induction of ornithine decarboxylase (ODC) activity and increased incorporation of |3H]thymidine have been documented after addition of crocidolite and chrysotile asbestos to a hamster trachea! epithelial cell line (J. M. Landesman an...

Asbestos induces a constellation of biological responses in cells of the respiratory tract that are similar to those of classical tumor promoters. In this regard, induction of ornithine decarboxylase (ODC) activity and increased incorporation of [3H]thymidine have been documented after addition of crocidolite and chrysotile asbestos to a hamster tracheal epithelial cell line (J. M. Landesman an...