In vitro effects of large and small glass fibers on rat alveolar macrophages.

The objective of this study was to explore the use of alveolar macrophage culture to evaluate the cytotoxicity of two glass fiber materials, a building insulation fiberglass (a relatively long and thick fiber) and a glass microfiber (a short and thin fiber). Alveolar macrophages were obtained from male Sprague-Dawley rats by bronchoalveolar lavage and were cultured with varying fiber concentrations for up to 3 d. Fiber toxicity was assessed by assaying cell viability, membrane integrity, and phagocyte function.

Particle activity and in vivo pulmonary response to freshly milled and aged alpha-quartz.

This study examined the possibility of freshly fractured alpha-quartz being more toxic and inflammatory in vivo than aged quartz of the same composition and particle size. Fresh quartz was generated by a jet mill, and used immediately, while aged dust was stored for two months before use. Both the production of hydrogen peroxide and hydroxyl radicals and the analysis of surface radicals verified the enhanced surface activity of fresh quartz.

Acute silicosis responding to corticosteroid therapy.

The course of acute silicosis usually is relentlessly progressive. Death results from cor pulmonale and respiratory failure, with mycobacterial infection a frequent serious complication. Attempts to treat the illness generally have been unavailing.

Cytochrome P-450-dependent metabolism in alveolar type II epithelial cells: modulation by platelet-activating factor.

Platelet-activating factor (PAF), an ether lipid mediator released from activated pulmonary phagocytes, was evaluated for its ability to affect cytochrome P-450-dependent activities in isolated rat alveolar type II cells. The data indicate that at non-toxic doses, PAF caused an increase in beta-naphthoflavone (BNF) inducible/alpha-naphthoflavone (ANF) sensitive ethoxyphenoxazone deethylase (EtOPx'ase) activity. At high concentrations of PAF, inhibition of both EtOPx'ase and metyrapone (MP) sensitive benzyloxyphenoxazone debenzylase (BzOPx'ase) activities and aggregation of type II cells were observed.

Inhibition of stimulant-induced activation of phagocytic cells with tetrandrine.

Tetrandrine is an alkaloid obtained from the root of a medicinal herb which is employed in China as a treatment for silicosis. One proposed mechanism for the development of silica-induced fibrosis is lung damage resulting from particle-induced inflammation and secretion of reactive compounds from alveolar phagocytes. Therefore, the objective of the present study was to determine if tetrandrine exhibited the ability to inhibit respiratory burst activity of pulmonary phagocytes.