Document baD6ok9yzY707Vw5o7j5wJZOZ

WV-11033 INDUSTRIAL HEALTH FOUNDATION, INC. * mi i' i " r --'m **.*. -- emmrmf m i ,. mm SUPPLEMENTSRY PROGRESS REPORT o* . HBROUS OUST STOJMES i* Johal-MaavUI* Corperotloa PPG Ii^uttri.. Corsiag Corporotioa -HR*rb* to*~M&Ltttaa, I. by Paul Grot*, W.D. Oirvctor of PotAoloff Ra torch StpUmbtr. 1974 - - *-- ' ^'j"wSXrSs.w'Wv Coaiol C. Brooa, M. RniUttt 5741 - ***# AVtuue .#imiuKH. #4 41233 <4t9> f-9l*0 Is % recent publication. `Aebeftoe-Ctadtteed latrathoraelc Tietae Keactioa, M we reported tbe results of or tmreetlgatioo that w * ponecred to pan bjr the induetrie# Ueted os tie title page and la port by the National laatitatei of Health. Heu bated ou % total of 292 fsteirert out of a total of 930 rate sad 2 50 fanrivore out of a total of 239 hameter*. ail of which bad been lajected iatrapleeraUy. The aoimeU not included ia tide report, e^uireleut to about 55% of the lojected rate and 37% of tie injected hamatera. were excluded became they had died too early of epidemic* of pal. menary dUeaee. By "too early'' 1* meant prior to tie time whet the firet tamer could be expected to appear. The atuenaU lajected lotratracheally with a*battoa euffered much greater mortality rate# tha& the azdmaU lajected iatrapleurally. Thla wee largely ettributable to the oeeeaaity of performing multiple intratracheal injection* la order to lotredact a euffieienity high dotage of duet into the long*. A dotage greeter than 2,75 mg war often lethal. Keweeer# in a prerioa* l&veeHgatiea long earner* hare bees pro* duced in rate at early ae 27 month* after atbe*toe exposure. At about * that time (la 1949) an epidemic of pneumonia decimated the animal* to a degree which forced Sr. Croee to replace the dead animate with sew ae la order to obtain meaningful reealte. to June# 1971# the** sew animal* were transferred to the Medical University of Seath Carolina under the general care of Dr. Carttek. D.V.M. About fix moathe after thia transfer, . an epidemic of pa*ojsoBla earned by mycoplasma killed meet of the animat* tnjeeied tatratrack*ally with amoelte. The rtiolt of thie high mortality 5742 A 2. among these animate u tUt no conclusions could be 4rwa. Although no Jung eeacere had developed is any of these animals, tie animals injected Intrepleurelly offeted e lever mortality end definitive conclusions were possible. These conclusions were incorporated is a report published is October. 1975. Microscopically, the lungs of tie animal* were characterised by extensive acute pneumonia which largely overshadowed the change* caused by the differeat type* of asbestos duet. There vat no discernible difference in the character of the UeU&i associated with the nriwi type* of asbestos or their modifications. Ke pulmonary tumor* were ttea However, be* cause of the over*helming nature of the a* todated pneumonia. no definitive conclusion is poaelble with regard to the differencee in. effect (if any) on the pulmonary tissues of the various types and modifications ofasbestos. Be cause the tracheobronchial tree of rodents wiU toUnto only eery small doses of asbestos dust suspensions, many injection* are required to attain proper dosage. As a result of this study, it has become painfully apparent that an investigation requiring the lungs to be loaded with a considerable vv asbestoa dust burden by means of numerous intratracheal Injections Is doomed to failure. This failure is assured by the fact that taeh intratracheal injection is associated with infective organisms that will ultimately cause fatal'pneumonia. Nevertheless, although the results of the Intratracheal injections do not allow for conclusions, the Results of the intrapleural injections suggest that amosite Is no less cancerogenic than erocidotUo and that chrysettle te 5743  a. appreciably less carcinogenic than either inoilu or crocldoHt*. It can alto be concluded that the pathogenicity of at! three type* of asbestos decrease* when they are heated to 900* to 1000* C for two hears, and that the tracemetal theory of the pathogenicity of asbestos most be abandoned. Aside from the conclusion* pertaining to the eancerogenic potential of the different types of asbestos, this investigation has demonstrated, as pointed oat in the accompanying reprint, "Asbestos-Induced Intrathoraclc Tissue Reactions," that celts other than mesothelial cells also may glee rise to cancers when materials are injected into the chest cavity. This demon stration casts doubt on the propriety of labeling all intmboracie tumors as mesotheliomas. Inasmuch as many of the intrathoraclc tumors are fi brosarcomas, and since fibrosarcomas arias spontaneously in rata, the validity of using the intrapleural injection technique in rate as tests for carcinogenicity becomes highly dubious.