Document EvYEkJK71Ee4LBp6q8rZ9Nx8g

- 2 i (L C ^ PLAINTIFF'S EXHIBIT DOW-279 ST00I2087 I . Wagner am!W. Sk i<!in<>rc .Ifi 'lint! /'/ >*<m,7i I'nriinniftinitisix I'r iitrfh Unit, IJiut'loifjli llus/iittif, /'* wtrlh, (Hnmttri/nn, Cn nt Hrilnin iMROmTIOM Tit previous animal dusting experiment* histological studies have estab lished <tilT*T'm*CH in the fibrogenic properties of various types of asbestos t Wagner. 100.1 am! elsewhere in this monograph I. Experiences with hu man ' .vo of pleural mesothelioma have indicated that these have occurred m.iinlv in association with the inhalation of crocidoiite, but in a current research project the intrapleural inoculation of a varr*" * J--- *v-- utile, emridolite, amosite. and silica^~^nto'r*t* mesotheliomas. The amount of dust inoculated. 30 mg., appeared by his tological examination to he greatly in excess of the amount found in the majority of human eases of pleural mesothelioma. In an attempt to clarify the position a scries of dusting experiments was planncC. and for this it was desirable to produce an experimental method l.y which c<pial amounts of any asbestos dust could be deposited in the lungs of rats by an inhnl.--.tion method. Additionally it was necessary to ascertain whether the various types of asbestos were retained in the lungs to the extent and had a similar histological distribution. With these objec tives a method was devised for producing the dust clouds and a preliminary experiment carried out. Mktiiou Fifty-seven mnJe and *8 female standard Wistar Albino rats were avail able for the experiment, nnd these wero randomly allocated on a statistical basis into S groups. Four uf the groups each containing 12 male and It female rats were exposed to airlmrne clouds of chrysotlle, crocldolite, amo site, nr powder*-*i glass; the first group was not exposed to dust, and the ral s making up this group were used ns controls. The powuered glass wait Included ns an Inert nonllbm'is dust for comparative purpose*. Rhodesian chrysolite and Sk.uth African cmcldullte anil amoslte were obtain* d In the most finely ground common-ini grade, nnd each was further ground in a mirrohamnu-r mill to break down any compressed lumps. 17*>***/ t'n-lurlinn The nir!>rne <lut rbunU wne generated by r* di<(*'t-.sing the ground i ! to>, .inti the ni* I >( is indh a ted seheuialletilly In t'l'.t'KK I. The ns- 77 DOUJ 06094