The effects of silica dust and alveolar macrophages on lung fibroblasts grown

Biochemical and Cellular Mechanisms of Dust-Induced Lung Fibrosis

“…Other investigators, using various techniques, have claimed to be successful (25), partially successful (26) or unsuccessful (27) in reproducing these studies. Indeed, in some instances a sufficient number of intact macrophages alone (without any stimulant) appear capable of inducing fibroblast cultures to deposit more collagen (26). Other workers (28) have fractionated a factor released from silicatreated peritoneal macrophages which enhances the incorporation of labeled proline into medium and cell fractions of granulation tissue slices (derived by sponge implantation) and into isolated polysomes from the same granulation tissue.…”

Induction of fibrogenesis by lung antibody-treated macrophages.

“…Kilroe-Smith et al (1973) extended these observations back to the in vivo situation by demonstrating a lipid free fibrogenic factor in alveolar macrophages isolated from silicotic guinea-pigs and by showing that this factor induced fibrosis when implanted under guinea-pig skin. Richards and Wusteman (1974), although unable to show collagen stimulation with medium supernates from silicatreated macrophage cultures, were able to show some stimulation using disrupted silica-treated macrophages and an even greater stimulation using intact untreated macrophages. They suggested that the intact macrophage making physical contact with the fibroblast was necessary to stimulate collagen synthesis.…”

Effects of chrysotile on a lysosomal enzyme preparation and on the hydrolytic enzyme activity of cultured alveolar macrophages.

“…Acid ribonuclease was assayed according to the modified method of Josefsson and Lagerstedt (13) and activity expressed as units activity/hr. Acid protease was measured by using partially denatured hemoglobin as substrate and activity expressed at jAmole tyrosine liberated/hr (12). (3-Galactosidase was assayed by using the method of Beck and Tappel (14), and results are expressed as ,Amole nitrophenol liberated/hr.…”