Document ZBOZZe1Z2BOYJ15DQEg4rv2BV

c formaldehyde resin. The histological studies of lungs of experi mental animals showed an extremely small fibrogenlcity of fnollte In comparison with anthophyllite. Nine months after the introduc tion of dust the average content of hydroxyprolIne turned out to be equal for "faolite" animals to 3281J, for "anthophyllite" 5763, for the controls 2375 wg (differences with controls are statis tically reliable). The average content of hydroxyproline for 1 mg of faolite dust was in this case 5 times less than for 1 mg of anthophyllite dust. Thus, the covering of the active sections of the surface by the bonding agent sharply decreases the flbrogenic potential not only of chrysotile but also of anthophyllite-asbestos. i 1 As is known, many silicates possess a flbrogenic ability. The especially increased fibrogenicity of chrysotile-asbestos is caused by its high specific surface area and weakness of the intracrystalline bonds which determine the formation of many topochemical centers which actively affect the biosubstratum. In vJ.V.i'.V-'.' turn, the indicated.features,of asbestos largely, are' caused by *. .SfcSRii L-wit; ;erml i^nyway. 5 large r^traumat1 al ng,.- Lrat f5*4tf<ie5rr/1 ... . . ............... .. best retention in the lungs (Timbrelli Skidmore,..i960,- , ___ . Al v.ely^ongjp art 1c (> 8 mg) are 12* of the total number of particles in the lungs of those who died from asbestosis, their surface comprises more than 50* of the total surface of all particles (Landvrehr,. , c Bruckmann, 1962). Thus, better retention in the lungs and the relatively larger active specific surface area determine the higher flbrogenic ability of longer fibers. 6000 0876 PRODUCED BY FORD