Document 3B49nObB4N97Kw9GvJ90X3v0

VORWALD ET AL__ STUDIES uF ASBESTOSIS 39 Pnortrnve Acrtox or Aukimm Cr'wroirx&s When cciloidal aluminum hvdrnxide h.-.u hern added to a sit*pciiNinii of long fiber chrysotiie prior to imcrtinr rht~ >..'pcn>im intratracheal!' into rats, the aluminum compound did iu<t prevent the irritation oi tissue due to cnrysoitlc. I: ant thing. the acute inflammatory response evoked by the injected fibrous mineral was accelerated. One month after the last injection of the ritisi suspension the bronchiolitis was becoming fibrous. King and his associates also found that aluminum failed to protect pulmonary tissue front the irritation caused hv ad>estn> fillers in their experiments metallic aluminum tva.* u?cd instead of the hydroxide. Formation or Asscsronts Eonir.s The iron in the coating of the asoestosis body apj>ears to be derived from blood or tissue elements and not. as lias been suggested, from the mineral fiber. After two kinds of chrymtle were injected su!<t:ranrouly into the groin of a guinea pig--one kind containing 2 per cent and the other 0.2 per cent ferric oxide--the asbestosis bodies were equally numerous at both sites of injection and showed no difference in their reaction to prussiai; blue, the reagent which stains iron. This finding is in agreement with that of Giroux.15 Tiisvt Rcactiox re Ascesrests Booits Asbestosis bodies recovered from human lung tissue and injected intratracheallv into guinea pigs failed to produce z fibrous reaction. The material ior injection was obtained Lv digesting with sodium hypochlorite solution the lung t:.:'r.e remove-! at autopsy from an aiLost'U worker. The asbestosis bodies ouiid be seen in tiie guinea pigs for at least a year after injection. This experiment shows that the asbestosis body has a rather resistant coating which is not destroyed by moderate hypochlorite treatment, which may he maintained in vivo for a year or longer and which renders the fiber incapable of producing fibrosis, it thus apoears that the coating is a protective mechanism. This thought was expressed by Beintker as early as 1934.'1 THEORY OF IRRITANT ACTION Two hypotheses have been proposed to explain the tissue irritation and reaction caused by asbestos fibers: the chemical ar.d the mechanical. In the chemical theory, which is hased on experience with quartz, it is assumed that the asnestos minerals dissolve in the body fluids and ilia: in this process ti;c:r bases are leached away to leave silica in a form capable of irritating tissues. According to this hypothesis asbestosis is mereiv an indirect silicosis. Several tacts make the chemical theory untenable: Intratracheal Injection of brucite fibers, which had a siiica 12. Giroux. Nt.: Arr.-.ir.sose exacrimentaic: vileur eitl-.ugnonomqu.' ilu "corps d'lmunte.'' Laval nud. S:239, 19aj. 12. Beintker. E.: Cbcr die A^ejtosi'ieorr^rce.en: Benttrlcungen tu der Arbeit ron 3eger. Virchows Aren t. pi"t. Anit. 133:527, 195-t