Biopersistence of commercial man-made vitreous fibers (MMVF) and crocidolite were studied in Fischer 344 rats. MMVF used were size-selected to be rat-respirable, and rats were exposed nose-only 6 h/day for 5 days to gravimetric concentrations (30 mg/m3) of two fiber glass compositions--a rockwool, and a slagwool--or to 10 mg/m3 of long-fibered crocidolite, or to filtered air. Animals were sacri...

This study investigated glutathione (GSH) homeostasis in human lung epithelial cells (A549) exposed to crocidolite. Exposure of A549 cells to 3 micrograms/cm2 crocidolite resulted in a decrease in intracellular reduced glutathione by 36% without a corresponding increase in GSH disulfide. After a 24-hr exposure to crocidolite, 75% of the intracellular GSH lost was recovered in the extracellular ...

BACKGROUND South Africa has, uniquely, mined, transported, and used crocidolite, amosite, and chrysotile. A multicenter case-control study was done in South Africa to examine the details of asbestos exposure in cases and controls, and to calculate relative risks for level of certainty of asbestos exposure, nature of exposure (e.g., environmental, occupational) and fiber type. METHODS Cases an...

Ten groups of rats were injected intraperitoneally with one of the following suspensions; (i) standard reference crocidolite; (ii) acid-treated crocidolite (iii) crocidolite plus iron oxide; (iv) crocidolite plus silica; (v) iron oxide; (vi) silica; (vii) long fibre crocidolite; (viii) short fibre crocidolite; (ix) long fibre glass and (x) short fibre glass. Two rats from each group were killed...

DNA damage due to reactive oxygen or nitrogen species is proposed to be involved in the molecular mechanism of asbestos-induced carcinogenicity. However, indications for this hypothesis came mainly from in vitro assays using cultured cells or cell-free systems. In the present study, the mutagenicity of crocidolite fibers and the underlying molecular mechanisms were investigated in vivo. Mutatio...

Crocidolite asbestos is toxic to macrophages in vitro. We hypothesize that this toxicity is mediated by the generation of reactive oxygen metabolites. Elicited mouse peritoneal macrophages were found to release reactive oxygen metabolites upon incubation with crocidolite asbestos in vitro. Crocidolite toxicity to both primary cultures of mouse peritoneal macrophages and P388D1 cells, a mouse ma...

The interaction of UICC crocidolite asbestos with biological membranes in vivo was studied in rats after a single intratracheal dose of a suspension of 20 mg of fibres per rat. Development of lung fibrosis (increased level of hydroxyproline, a collagen index together with corresponding pathomorphological alteration) confirmed the penetration of crocidolite fibres into the lungs in the course of...

Metabolism of inositol phospholipids and phosphatidylcholine was investigated in tracheobronchial epithelial cells exposed to mitogenic concentrations of crocidolite asbestos. Alterations in levels of diacylglycerol, the endogenous activator of protein kinase C, and inositol polyphosphates, presumed mobilizers of intracellular calcium, were examined. Cultures labeled with [3H]glycerol and expos...

Fiber length and diameter are important factors in the pathogenicity of asbestos. We examined the relative toxicity of long and short crocidolite asbestos fibers in vitro and in vivo. Both long and short crocidolite asbestos fibers were toxic to elicited macrophages in vitro. Similar to native crocidolite asbestos, long and short Tibers stimulated the release of reactive oxygen metabolites from...

Mesothelioma is considered a signal tumor for asbestos exposure and typically occurs decades after first exposure to asbestos. Tissue analysis often indicates past exposure to mixed types of asbestos. This report describes the case of a 58-year-old man who developed mesothelioma after reported exposure to crocidolite from asbestos-containing gaskets beginning at age 16 during three summers duri...