Biochemical changes during carcinogenesis by plastic films.
نویسندگان
چکیده
The fac t t ha t sarcomas are induced in rodents by imbedded films of polymers has been established in this l abora to ry (1~-15) and had been conf irmed by a number of o ther invest igators (~, 6, 8, 10, 19). Subsequent studies have shown t h a t this phenomenon is not l imited to films of organic polymers b u t t h a t imbedded meta l foils have the same effect (9, 10, l l ) . This fact , in addi t ion to the finding t h a t powders of the same substances do not induce tumors , indicates t h a t the carcinogenic ac t iv i ty of the polymer is a resul t of the physical presence of a film ra the r t han of some chemical reaction. To learn more regarding the react ions and the changes which take place in the tissues when a film is imbedded, invest igat ions were carr ied ou t on the tissue ad jacen t to the film from the t ime of imbedding to the period when the tumor appears . I t was found t h a t one of the ear ly react ions is the envelopment of the film by a pocket of fibrous tissue. The impor tance of this pocket in the carcinogenic process is demons t ra t ed by the fact t h a t the tumors develop in this tissue and tha t , when the pocket is removed, no tumors are formed. I n a previous publ icat ion (16) we repor ted on some histologic changes which occur in the adj acen t tissue dur ing the precancerous stages. These involve, successively, fo rmat ion of cellular g ranu la t ion tissue, generalized fibroblastic activi ty, and a th ickening of the pocket . After about 4 mon ths fibroblastic ac t iv i ty is reduced; the pocket wall has re lat ively few nuclei and appears to become progressively less active. This s i tuat ion ei ther cont inues indefinitely or, in some cases, a f ter 6 mon ths fibroblastic ac t iv i ty is renewed in isolated patches. I n these pockets there m a y be var ia t ions in the cell size followed by fo rmat ion of p resa rcomatous and sa rcomatous cells.
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ورودعنوان ژورنال:
- Cancer research
دوره 19 شماره
صفحات -
تاریخ انتشار 1959