Polyethylene/chrysotile nanocomposites with different amount (0.4 to 6.7 wt%) of filler were prepared by in situ polymerization method using the metallocene Cp2ZrCl2 as catalyst and methylaluminoxane (MAO) as co-catalyst. Previous to polymerization, raw chrysotile was treated by three different methods that used thermal treatment and acid leaching. In method A, raw chrysotile was treated therma...

Escherichia coli as a plasmid recipient cell was dispersed in a chrysotile colloidal solution, containing chrysotile adsorbed to plasmid DNA (chrysotile-plasmid cell mixture). Following this, the chrysotile-plasmid cell mixture was dropped onto the surface of an elastic body, such as agarose, and treated physically by sliding a polystyrene streak bar over the elastic body to create friction. Pl...

The kinetics of the bronchoalveolar response was assessed in rats exposed, at equal airborne mass concentration (10 mg/m3), to titanium dioxide--a non-pathogenic dust--and the two pathogenic mineral dusts quartz and chrysotile asbestos. Rats were killed at intervals over a 75 day exposure period and groups of rats exposed for 32 and 75 days after recovery for two months. Bronchoalveolar lavage ...

Four groups of rats were treated by inhalation with the UICC preparations of amosite or chrysotile in order to explore the effects of intermittent high dust concentrations (peak dosing). For each of the 2 asbestos types one group of rats was treated for 5 days each week, 7 h a day, for 1 year. Two other groups were treated with amosite or chrysotile at 5 times the previous dose for 1 day each w...

Synthetic stoichiometric and Fe-doped geomimetic chrysotile nanocrystals represent a reference standard to investigate the health hazard associated with mineral asbestos fibres. Experimental evidence suggests that the generation of reactive oxygen species and other radicals, catalysed by iron ions at the fibre surface, plays an important role in asbestos-induced cytotoxicity and genotoxicity. I...

This study compared pulmonary effects of para-aramid respirable-sized, fiber-shaped particles (RFP) (p-aramid fibrils) and chrysotile asbestos fiber exposures in rats. Additional p-aramid inhalation studies were conducted in hamsters to compare species responses. The hamster results are preliminary. The parameters studied were clearance/biopersistence of inhaled p-aramid RFP or size-separated a...

Dr Egilman and colleagues claim our report 1 implies that chrysotile does not cause mesothelioma. So did the International Chrysotile Association, the website of which highlighted our paper with the misleading headline 'reliable scientific data confirms negligible role of chryso-tile in UK patients with asbestos-related lung disease'. 2 Our results are consistent with the strong evidence that c...

A review of the literature on chronic inhalation studies in which rats were exposed to mineral fibres at known fibre number concentrations was undertaken to examine the specific roles of fibre length and composition on the incidences of both lung cancer and mesothelioma. For lung cancer, the percentage of lung tumours (y) could be described by a relation of the form y = a + bf + cf2, where f is...

The radiation diffraction pattern for amorphous materials requires special analysis for information on atomic groupings. Powdered crystalline material may also give diffuse patterns requiring this type of analysis. Absence of a sharp diffraction pattern does not necessarily indicate absence of the material. Examples are given for chrysotile and powdered chrysotile.

Alterations in erythrocyte membranes caused by UICC B chrysotile asbestos fibres were studied in red cell ghosts using the spin label technique. The electron paramagnetic resonance (EPR) spectra of two sulphydryl reactive spin labels and one fatty acid spin probe in erythrocyte ghosts showed membrane protein modifications but no changes in lipid fluidity caused by the haemolytic chrysotile asbe...