Document N2OpedqnnJRj8kNLoYDQpv1YD

c n It Is especially interesting that induction of cancer is Increased with supplementary administration of stilbectrol. It is necessary to recognize that we still do not know the basic reason for the malignant action of asbestos. At the same time, based on the well-known physicochemical features of asbestos, we shall put forth a number of hypotheses which deserve, as it seems to us, a check. Many authors ascribe the carcinogenic action to chronic stimu lation of bronchial tissue by rigid fibers. However, it is known that only a small percentage of traumas is created by stimulus to malignant growth, relatively more solid powders of fiberglass or abradants do not possess such carcinogenic properties. 1 ;v; " o Scar Itself can hardly be the basic reason for malignency; indeed with silicosis, where the fibrosis is more considerable, a considerable Increase in the frequency of complications of cancer . of the lungs is not observed. At the same time, as observed by us, the chronic pneumonia and the metaplasia of bronchial \epithelium that appear under the effect, of asbestos make the.,- . .... lengthen its effect. V-?S: During; the, Introduction of .polymers, around them there occurs .......v*.. I .|rA* a formation of a connective-tissue"capsule, within which, young * *-' . . *..*. :**,**. " <* s'*.' ,, ' ***v '' v ** 'V ; * . fibroblasts' and.'a .thickened'layer o'f* collagen develop''(Shabad 1>. H., 1967)* The constant presence of.metachromatic poly-"" *l,vfr.:^.&i*ii^^aecharldea\indic'fttfeftjibi&^^^ ^the`proliferation Vvjr'|*ifws'-S..fibroblasts within the-..capsule leads.to the appearance of increasingly .. f' y . less differentiated atypical cell.- J? In accordance with the hypothesis of Prof. L. M. Shabad, 19^7 2* these multiplying and infiltrated (through the capsule) fibrobiasts precede sarcoma. It is possible also that during the prolonged effect of asbestos, which i6 an inorganic polymer, there is a 17 aooo 0880 PRODUCED BY FORD