M. Waseem

Ranking toxicity of industrial dusts by bronchoalveolar lavage fluid analysis

Female wistar rats were inoculated intratracheally with 10 mg/ml suspensions of various dusts, viz: quartz, fly ash, mica and corundum in physiological saline. Biochemical markers of bronchoalveolar lavage fluid (BALF) were analysed 8 days after the instillation of the dusts. Elevated levels of proteins, sialic acid and phospholipid contents and the activity of lactate dehydrogenase correlated well with the degree of the known fibrogenic potential of different dusts in the lungs in the following order, quartz greater than fly ash greater than mica greater than corundum. beta-glucuronidase activity, was however, only elevated in the quartz inoculated group of rats. It is suggested that biochemical constituents of BALF analysed shortly after the exposure to different dusts can be useful to mirror alterations in the tissue response to mineral dusts.

Modification of pulmonary silicotic reaction in rats exposed to coal fly ash

Quartz exposure resulted in an increase in the wet weight, dry weight and collagen contents of lungs. Animals inoculated comparable amounts of fly ash revealed a statistically insignificant increase in these parameters. In silicotic rats exposed to fly ash the increase in the wet weight, dry weight and collagen contents of lungs was reduced in comparison to silicotic animals unexposed to coal fly ash. Histological examination of lungs revealed the development of silicotic granulomata with reticulin and collagen fibre formation. The difference in the development of these lesions was less pronounced when a blindfold comparison was made between the silicotic animals, exposed or unexposed to coal fly ash. The increased activity of LDH in the bronchoalveolar lavage (BAL) of rats exposed to quartz alone was mitigated significantly in silicotic animals subsequently exposed to coal fly ash. The protein content of the BAL increased significantly more in quartz-fly ash exposed animals than in rats exposed to either dust alone. The total cellular elements of the BAL were increased in rats exposed to quartz alone (p less than 0.005). The results demonstrate that fly ash exposure can significantly modify the development of a silicotic pulmonary reaction.

Pulmonary clearance of Candida albicans : Effect of exposure to native and metal-coated fly ash

The viability of Candida albicans was tested at various intervals in the lungs of rats following single intratracheal inoculation of the yeast cells. Most of the inoculated cells were cleared from lungs within 48 hr after exposure. Clearance was enhanced in lungs exposed to metal-coated fly ash than in those exposed to native fly ash. The validity of these studies was verified in vitro using peritoneal macrophages of mice exposed in vivo to native and metal-coated fly ash. An increase in phagocytic and intracellular killing of macrophages harvested from animals exposed to native or metal-coated fly ash was observed.

In vitro cytotoxic and hemolytic potential of coal fly ash

Abstract The cytotoxic and hemolytic potential of coal fly ash derived from a number of thermal power stations in India was investigated on guinea pig macrophages and mammalian erythrocytes respectively. The cytotoxic studies were carried out using graded concentrations of fly ash. Fly ash‐macrophage interaction resulted in increased release of LDH into the supernatant culture medium. Acid dye uptake was enhanced only when the interaction ensued in a serum free milieu. Both the extent of enzyme release and dye uptake were significantly more in quartz exposed cultures than in those exposed to fly ash. In hemolytic assay all fly ash samples produced only a meagre hemolysis of erythrocytes, irrespective of the mammalian species from which the erythrocytes were obtained. Concentrations which produced more than 75 percent hemolysis of quartz exposed erythrocytes produced less than 10 percent hemolysis when erythrocytes were exposed to fly ash. These results reveal a weak membranolytic activity of coal fly ash.

Pulmonary response to graded doses of coal fly ash in rats

Abstract The effects of an intratracheal inoculation of graded doses of coal fly ash were investigated in the lungs of rats. Animals exposed to increasing concentrations of the dust did not significantly increase the wet and dry weight of lungs. Collagen contents of lungs, estimated as hydroxyproline, increased significantly with lapse in time and was dependent on the dust concentration used. The dust produced a marked macrophage response in the alveoli and a thickening of the interalveolar septa, due to cellular infiltration and proliferation of argyrophilic fibres. Irrespective of the amount of dust injected, foci of dust laden macrophages were present in the mediastinal lymph nodes at all time periods. In the bronchoalveolar lavage the number of cells increased very significantly with an increase in the amount of fly ash injected. Increase in the cellular constituents of the bronchoalveolar lavage was associated with a statistically significant increase in the lactate dehydrogenase enzyme activity and ...