This article reports the effect of coexposure to Indian chrysotile asbestos (5 mg/rat) and kerosene soot (5 mg/rat) on the pulmonary phase I and phase II drug-metabolizing enzymes 1, 4, 8, 16, 30, 90, and 150 days after a single intratracheal inoculation. Exposure to soot resulted in a significant induction of the pulmonary microsomal cytochrome P450 and the activity of dependent monooxygenase,...

For more than 40 years, intensive research has been devoted to shedding light on the mechanisms of asbestos toxicity. Given key role fibre length in toxicity, much work finding suitable comminution routes produce fibres desired size intervals. A promising method is cryogenic milling that, unlike other mechanical reduction techniques, preserves crystal–chemical properties materials. In this stud...

The traceability of asbestos fibres in human lungs is a matter of discussion especially for chrysotile. This issue is of high significance for differential diagnosis, risk assessment and occupational compensation. At present no intra-individual longitudinal information is available. This study addresses the question whether the asbestos fibre burden in human lungs decreases with time after expo...

Crocidolite and chrysotile asbestos and the tumor promoter, 12-O-tetradecanoylphorbol-13-acetate (TPA), induce ornithine decarboxylase (ODC) in hamster trachéalepithelial cells (HTEB). When added at the time cells were plated, non-growthinhibitory amounts of crocidolite (0.64 to 1.28 ,ug/sq cm) and chrysotile (0.064 to 0.13 fig/sq cm) asbestos increased ODC activity 2to 3-fold after 24 to 30 h...

A lung cancer case-control study was conducted in a Slovenian asbestos-cement factory for which unusually good records of asbestos exposures were available. The cohort consisted of all 6714 workers employed at the Salonit Anhovo factory after 31 December 1946 who worked there for at least one day between 1964 and 1994. Fifty-eight histologically confirmed cases of primary lung cancer and 290 co...

This is a study of workers at a friction materials factory founded in 1898. Crocidolite was used only during two well defined periods before 1945. Apart from this, only chrysotile asbestos has been used. The mortality study dates from 1942 and extends to 1979. Over 99% of the population have been traced. Ten deaths from mesothelial tumours occurred. An analysis contrasting the observed number o...

Talc deposits include asbestos minerals such as chrysotile and amphiboles that may be carried over into consumer products. Optical microscopy and x-ray diffraction analyses may not reveal their presence. Examples are given of electron microscopy procedures that permit detection and measurement.

Palygorskite, a fibrous clay mineral, is being used as a substitute for asbestos in some applications. Nine specimens obtained from different geological locales were studied for mineral purity, elemental composition, fibre size distribution, and surface binding characteristics. The membranolytic activity of each was determined using a human erythrocyte model. The membranolytic behaviour and sur...

In the 1960s and 1970s, well designed case-referent studies put beyond doubt that exposure to airborne asbestos fibres was a cause of malignant mesothelioma. Some 35 cohort mortality studies in a large variety of industries during the 20-year period, 1974-1994, showed a wide range of outcomes, but in general that the risk was higher in exposures which included amphiboles rather than chrysotile ...

Fiber length and persistence are thought to be determinants for the development of toxic, fibrogenic, and carcinogenic effects of fibrous dusts. When the solubilities of chrysotile asbestos (CA) and basalt fibers (BF) were compared by measuring the loss of silica and magnesium in Leineweber's solution, CA was shown to be the more soluble. In a 6-month inhalation experiment, chrysotile at a mean...