Document 6wJ8DGDzNXEGYyop1zJZZ3aGm

yQRWALD ET .<L.--STUDIES Or AS3EST0SIS S own essential lining is a low cuboidal type of epithelium hut. as their name implies, they actually function in respiration throuoh lateral aiveoii distributed along tiietr wail*. F.ithcr these ai\eoii or the abrupt change m the character of the lining epithelium, or the small diameter oi the respirators- bronchiole, or the cnmmnation of ail three factor.' is responsible for. retention oi the fiber at this sue. Only after asbestosis is well established are appreciable numbers of fibers seen in the more peripheral air spaces. Further explanation is required to clarity tins observation. Rare or Tissue Reaction rn Asbcstos Fittas The affected tissues react mud; more rapidly to asliestos than to quartz dust. For example in rats receiving asbestos fillers by intra tracheal injection fibrosis of a characteristic type is visible as early as one month after injection; for quartz dust the latent period is two months or more. Thus, the development of nodular fibr^is due to inhaled silica lags behind the deposition of dust to a greater extent th n does the evolution of the diffuse reaction to asbestos. This results i:i a difference in the degree of progression which follows termination f exposure to dust. For example, on discontinuance oi exposure t e nodules of silicosis become larger, to a limited extent, for a con>iiier.ii.;c period of time, whereas the fibrosis of asbestosis increases for only a short time. Subsequently, the asbestotic fibrous tissue contracts; this process often distorts the adjacent pulmonary tissue and may. as a result, progressively interfere with cardiorespiratory function. Asszsttkis 2-*:vfs The peculiar structure known as the asbestosis body or "curious body" is a specific concomitant of asbestosis.1 The typical Ix-idy i' a golden yellow, beaded or haustrated rod. which may be either straight or curved (fig. 2). Often one or both ends are bullious like a dumbbell. The bodies vary consiuerably in length, and dimensions up to 220 microns have been recorded. It is believed that asbestosis bodies are inhaled fibers on whiih pro tein and iron ptgmeut o: tissue origin have'Leen deposited.'- Gloyne :o observed reproduction of these bodies in guinea pigs nine montits after subcutaneous injection of fibers rendered free of iron. The bodies are abundant in mart anu in the guinea pig (table 1) but are much iarger in the former, probable because the larger-sized air parages admit fibers of greater dimension. In guinea pigs they form it.cr about 70 days 5. Giovne. S. R : (ui The Forrr.ition oi tise Asbestosis Body r.i :he L-r.c. Tubercle 12:293. 1921 ; iPj The Asbestosis Hour. Lancet l::i:I. 19J2. (cl Card- ner and Cumrain^j.' 6. Lyncn. fv }!.. ir.i Smith. W. A.: Asbestosis Eodies :n Sputum and Lur;. J. A. M A. 3i:C;v f.Vjj. 301 130. Simt-ru F. W . ;.-.i Stnccin. A. S.. Asbestnsu Bodies m :ne Srurum: A Studv of Srecimeni from i} Workers in in Asbestos Mill. /. Path. & Cact. 31.'!. 1931. Garancr ana Cummings.'* Gardner.lb Gloyne.J*- 56 Tl> xrr-cr in --