Document 7MQ5rG9zjzgRgDQ12jOXe98ej

AS3 !S70! T S2. fP T tiiTHODUCTIOH Asbeetools is a fora of pneumoconiosis.resulting froa prolonged . . inhalation of uabcatos dust. The name aabostos, literally *unburnablet" ie not that of a spool fie mineral but le a torn applied to a number of different alaorals whoso oharactoriatlo feature le a structure composed of long, parallel, flexible flbera. This structure le unique because ths fibers are capable of repeated longitudinal subdivision to unite of ' molecular proportions. In length the flbera vary from few mierona to sic or moro Inches. Como varieties are otlffer than others but many are sufficiently floxlblo to ba spun into yarn and wovon on modified textile uaohinery. , ... Tbo asbestos minerals are ollloobea of rarlablo composition and be long to the aorpontine and the emphlbole groups. Listod below are the maro oosnian varlotlas. . Amohlbolo Group ' ' ' Aotinollto ' Anthophylllto Ainoalte Crocldollte . Amphibole. . .Tremolite .. . . . . Serpentino Group Chryootllo --/ -The bulk nf tho asbestos of cotsmoroe is ohryaotlle, SUgO-ESlOj^tt^, which Is mined on this continent prinolpally In the Thetford region of the Proylnae of Quobee and In Vermont. Crocldollte and aaoslte also are '\ -1- I T usod commercially but la i.udi smaller amounts. Chryaotllo ocouro as Tains In serpentine, e minora1 of similar chomloal composition,*hloh exists in massivs form and is mads up of microocopio fibers without tho parallel orientutioo charactoristio of chryaotllo. Tho masaivo bludsh* % black sorpantlnn, nhioh is smooth sad soapy to the touch, la traTorsed by Tolns of fibrous chryaotllo varying In width from e baroly perceptible lino to six of moro inches. The fibers run aoross the vein and not length wise with the formation. Attention is directed to the mineral brueite, IfgO^KgO, which la often found in tho ea-io formations with eorpontlne and chryaotllo ^nd may bo fibrous In structure. Exoept for the manufacture of magnesium, brueite has no comwrclnl value at proaont baoauao its fibers are not sufficiently . flexible to be used in toxtilos, but they are capable of repoatod longi tudinal subdivision. Unlike other asbostlform minerals, brueite la not a allicato and for this reason it has been a valuable tool in an erperimental evaluation of "the action of fibroua minerals upon lung tlaaua. EXPERIMENTAL ASBESTOS IS For many years etudies^*^ have boon oarrlod on at the Saranac Lab- oratory in an investigation of the cause, nature and development of asboatoela. The precent paper.le devoted.to experimental asboataats and in It1 2 1.<'Gardner, L.H. and Cummings, D.E.i Studios on Experimental Pnoumoeontoais. VI. Inhalation of Asbestos Oust. J. Induet. Uyg. 13 65, 07, 1931. 2. Gardner, L.U.t Chryeotllo Aebeetos as an Indicator of Subtile Dif ference! in Animal Tissues. Am. Rev. Tubero. 45t 7G2, 1942. 2 r. </ ( in.Ai. P. j'Vf /<.<_ j, 'i .. . ... , . V*.*Ay- EXPESIUEKTAL STUDIES OF ASBESTOSIS* : , ' P1/^/ *jr . Arthur J. Vorwald Thomas U. Durban Philip C. Pratt from Tho Saranao Laboratory of Tho Edward L. Trudeau Foundation Juno 1, 19S0 t Thla aorloa of atudloa of asbestoslo, lnitlatad at tho Saranao . Laboratory more than twenty yeara ago by tho ThbsDr. Loroy U. . Gardner, director of tho Laboratory, vraa nearly ooapletod at tho time of Uia death in October 1946...Although partial reports.and informal revtowe of aoino of tho orporlmonto had boon glvon from tlno to tine by Doctor Gardner, this paper prosoots for the first tino a complete survey of the entire experimental Investigation. r aro dosorlbod Iho animat .. ;pnrtocnta with various kind* of aobectoe dust. Another .rP*t, to be prepared and Issued at a future date, mill be eoacomed with human asbeotojls and vlll oovor the health aepocts of workers who liavo boon oxpoaoi) to asbestos dust In an Industrial onviran- ' meat. ' Although asboetosls in man is ohronlo disease with diffuse pulaon- year n ary fibroaia which require:/to develop. It is possible to reproduce In one or wore apecloa of animal charaoterietlo tissue changes whloh are similar to the lesions of human asboetosls, (fig. 1). Sinco the life-span of the experimental animal 1s rolativsly short, it Is not possible to develop the characteristic lesions in animals under conditions identioml with the . usual Industrie! environment. Consequently, to obtain a oooplete evalum-- . tion of the tlesuo respoose to inhaled particulate and fibrous material. It la neonssary to acoolorate tho reaction by employing higher concentra tions of dust than would ordinarily be eaoountorod in Industry. Vhlle conditions of exposure are thus different, the information ylolded by exnerlBonte with animals is Invaluable in furnishing si bottor understanding of tho reaction of tho hitman organism to Inhaled asbestos dust. Experimental Methods. . Por investigating tho tissue roantlon of th* *... . experimental animal to tho various asbestos minerals, two typos of technique have been employed, namely, tho inhalation mothod and the injcotlon method. In inhalation o^porlmontn, groups of animals - up to 100 or more guinea pi/s and somotluoa smaller mimbors of rabbito, cats, dogs, rats or mice are kept for altjtztr hours a day in a cubloal dust room, e^ht feat in di mension, In which a cloud of asbestos duet la maintained by a rotating t -3- W T tL c . paddle In a dust hopper^1*. At Intervals during the experiment, a feu on Inals are aacriflood and tho tissue examined to deterulne the nature and extent of the dust reaction. Conu animals are exposed for pcirloda up to three yoi*rs. The Injection experiments are usad to determine Ln as short a tlwo os possible whothor or not a partioular duet has a po tential capacity to produco inflammatory reaction when in direet oontaet < with tiecuoe of tho body, The method Involves lnjeotlon of the dust, either dry or uuspendod ln fluid. Into tho animal by the Intravenous, the the intrsperitonoal^/lntratrachoal, or othar router.. Long-term inhalation experiments furnish information upon "which^ ' . great roliancs la placed when estimating the degree to whieh a dust might constitute a respiratory hatard to Industrial workers. Evon though an atmospheric dunt may be potentially dangerous, as indicated by Injoetlon experiments, only inhalation procedures will rovoal whether the dust oan bo inhaled, pass the natural defense barriers of the body and reaoh tho pulmonary tissue In quantities sufficient to oause damage. Injection methods are useful, however, beosuse they mako certain that contact oc- ours between tho dust partlalas and tissues and booauoo they allow accur ate estimation of the dosage and of tho potential capaoity of that doso to produoe reaction. The intratraohesl method la particularly valuable when dealing with fibrous minerals like asbestos, since it permits obser vation of the effect of tho fibers on pulmonary tissue. ../ Tlssuo Susceptibility. Unlike free silica, asbestos, dooo not pro duoe spoclfla effect ln all organa of all opoolea of aulmal. Comparative -4- cc data, prosontod la tsblw l. Is based upon oouplotod observations and .' . ... |tl J ' therefore differs slightly fron a prelirainary report(2)# Introduction of fine quarts into various organs of the guinea pig, rabbit, rat, nouse, cat, dog, chicken and even tadpole eventually Drill produoe silicotic no dules but at o different rsto of development. Similar introduction of S&5vnininHi>!itmii' asbestos has rosulted in a fibrous rsaction In the lung and, to a lesser extent, in the peritonevna but not in other organs of the guinea pig, rabbit, cat and white rat. In our experience the lunge of the dog and white raouso failed to respond with fibrosis although . Sohustor^} hau roportod such change a In a dog that lived In an asbestos fabricating plant. This variation In species and in organ suaeoptlbllity is yet to be accounted for(^); it la prasuoad that in the.susceptible . Afllsalo the griutor roaction of the lung to asbeetos, for exeeeding the reaction of othor organ tiasuos, la due principally to the greater nobility of the lung. .... . Peculiar Charsoterlatlos of Asbestos. Experience has demonstrated that moot of the non-flbroua particulate dust Inhaled into tho lungs of van and animal la 10 nierona or leas in maximum dimension. Largor parti cles apparently do not gain aooeaa to the lungs beaause of two roasonar first, large particles settle in air so rapidly that few remain suspended 3. Schuster, H.U.i Pulmonary Asbestosis in a Dog. Part 2, 751, 1931. ,/ . and J. Path. / bsct. ill 4. Vorwald, A.J.t Variatlona in Individual Susoeptlblllty to Industrial ' Dusts Inhaled into tho Lungs. Am. ttev. Tubsro. 62 IB, 13, 1950, --6-- in the atmosphere breathodi oeeond, largo particles are moro effootively removed hy the protective Bieohenioma of tho upper respiratory tract. In the eaao of fibrous noterlals these factore have loss influence and fi- beru 100 and even 00 microna in length haro beon found in the toroical air spacos of human lungs. In small laboratory animals exposod to asbestos dust tho maximum length of fibor found In the lung raroiy excoods 60 clerons, A largo proportion of non-fibrous partioul&te dust inhalod into tho lung Is found In tho terminal sir spaces (alveolar duct, atrlu, alveoli) . in all parts of tho organs In contract, inhaled asbestos fibers are ,flrst discovered in the respiratory bronchioles. Those email passages ars im mediately distil to bronohiolae lined by dilated epithelium^). Their . own ossentlel lining Is a low ouboldal type of epithelium but, ns their name implies, thoy actually function in rosplration through lateral alveo li distributed along tholr walls. Either these alveoli or tho abrupt change in tho ch&raoter of the lining epithelium'or the small diameter of the respiratory bronchiole or the combination of all three factors is re sponsible for retention of the fiber at this alto. Only after asbostosie is well established are appreciable numbers of fibers seen in the moro peripheral air spaoas. Further explanation is roqulrod to olarlfy this observation. . Kate of Tissue Hoartlon to Asbestos Fibers. The tissue reaction to asbestos develops much more rapidly than does tho roaotlon to quarts dust. 6. Killer, *11 Ham 3.t The lung. Charloa C, Thomas, Publiahora, 1937. -6- r( t'ur example, In rata rocjt-lng asbestos fLbars by Intratracheal Injoa- tlou flbroala cf characteristic type la vioibla aa early aa one month after lojaetionj for quartz dust tho latent period la two seethe or oore. t. * Thus, tho dovolopcent of nodular flbroala duo to luhalad alllcu lags bo- hind tha deposition of duet to a greater extont thmi^doea tho evolution of tho diffuse roactlou to sabaatos. This roaulta In a dlfforouco in the ; *I * dei;roo of progmsaion which follows termination of oxposuro to dust. For example, on discontinuing exposure, the nodules of ailicoais boo olio larger, to a Halted or tout, for considerable period of .tlus, whereas tlie fi brosis of aaboiitoela Lnoroauus for only a short time. Subsequently, the ** - asbostotlo flbroala contracts* thle prooese ofton distorts tha edjeoeot t; pulnonary tissue and nay rosult in a-progressive lnterfareaoe with cardio- reii?iratory function, .. Ashostoals Dodloa, Tho poculiar structure known as tha sahastoeie body or "ourious body" is a apoclflc concomitant of asbestosis^***^. The typical body is a golden-yellow, beaded or haustratod rod which may be either straight or curved (figs. 2 and 3), Often one or both ends are bulbous like a dumb-bell. The bodies vary considerably In length, and dimensions up to 260 aicroua have bean reaordod, - It la believed that asbostosle bodies are due to a deposit of protein and iron pigment of tissue origin upon the surface of lnhalod fibora6 7 6,'^Cloyno, S.H.i Tho Formation of the Aabeatosis Body in the Lung, Tuborele 12t 398, 1931. ............... - - . 7. Gloyne, S.R.i Tha Aabeatosis Body. Lancet, 1361, June 26, 1932, ' \ -7 (l2Gi7iCleyno^'^ reproduced bndlos 9 months aftor subcutonoouo injection in guinea plge wf fibers rondorod free of Iron. Tho bodios aro abundant in nan and-In tha guicca pig (tablo 1) but ere much larger in the former, probably becauoo tho largor-fltod air passages ad.ait flbora of greater dimension. fn guinea pigs they form after about 70 days of contact *lth the tiasua. In oota, rabbits and mica there to an atypleal coating of a fow of tho. fibor a after such longer rcsldonco in the lungs. In rata^hodloe are rarely seen and in dogs nomi could be found. Although the evidence la Incomplete, It appears that the formation of the aaboaloslo body provonts dmuage to the tissue by tho fiber, -/any of the points montlonod above will be elaborated upon la aubsequeat para-- graphs dealing with tho aotur.l experiments. ..For pro floatation our lnveatl* gallon Is divided into two sections, ono doollng with inhalation export*' meuta end tho other with Injection experiments. ' i. XBUALATXOU EXPERIMENTS Four large-scale inhalation experiments have been conducted in this laboratory with various forms of asbestos dust, tn eaoh of those Investi gations noro than ICO animals were used and tho, oxporlaonta were oerrlod on for periods ranging from 2 to sore than 5 years. Tho four kinds of as bestos dust employed are designated as Xing's floats, short-flbor, 100 per cent ball-ioillcu, and lcng-flbor asbestos duct.* 9 8* Lynch, K.M, and Smith, tf.A.i Asbestools Bodlos la Sputum and Lung. J.A.U.A. 9L 65Q, 1930. -. 9. Simoon, F.l. and Strachon, A.S.t Asbestoola Hodles in ths rputua; A Study of rpaolmena from Fifty Korkora in an Asbestos Mill. J, Path, and Dat. 34t 1, 1931. \ r c\ . KItlGS FLOATS AS1JESTOS WIST The first Inhalation experiment oonduotad at tha Earanao Laboratory with aabaatos duafe was begun in 1928, Animals inhaled tha dust for periods up to S3 months. Soma guinea plga with 8 and 9 months1 exposura lived for an additional threo years after cessation of their exposure, A preliminary roport^J presented observations aftor 29 months of exposure. At that time observations covered a period of only 2-l/4 years and the conclusions as to tho ultimate effects of in halod asbestos dust wore provlalcnal. Those conclusions are substantiated by results of the completed study, whioh Is reported as follows. Composition and Atmoaphorio Conoontratlon of the Dust, The dusting material, t_ a oonnerolal verloty of asbestos known as Xing's floats, was ooaposod of short a , ,, ,. fibers, ranging In length from 1 millimeter to 1 micron or less, end of partlolse * whioh also varied in alto. It trio obtained from the Thetford, Quebec plant of the Asbestos Corporation of America and analyses (tables 2 and 3) reveal that the amount of fibrous ohryaotlle was only .14 por oent, a rather low value, Iaplnger samplas takoa soon after the experiment waa started indicated that the dust concentration wma at first quite low, the average dust count being only 6.0 million particles per ' ' for eublo foot of air by the standard light-field technique and 0.8 mllllon/partlclas and fibers groator than 10 microns. After tho inhalation experiment had been. under way for about two years, the speed of tho rotating paddlo In the dusting maohine waa increased and for the remaining 10 months of tho experiment considerably more . dust was dispersed into the atmosphere, Tho average dust count of lmpinger samples collected after this change was S3,7 million by tha usual light-field method and 1,6 million far particles and fibers larger than 10 miorona. It la probably, haw- It ever, that the true values of the dust conoontratlon ware higher than the counts . glvon In this paragraph. The lmpinger samples for the King's floats experiment ware -9- ( oollaoled In water but loi o: 4tudio^10^ have shown that counts of lmpinger a V piss of asbestos dust taken In vator arc not reliable; Ethyl alcohol instead of p', Ln all subsequent experimenta. vator was used a* tho collecting fluid Results of the investigation, briefly sumarlsed ln table 4, show that in halation of King's floatu asbestos duet produced a typical psrlbronohlolsr fibro sis In guinea pigs but not in rabbits or rats, - Hoaotlon ln Ooreal Guinea Pigs. Quines pigs Inhaling this dust for periods up to 33 months developed a characteristic fibrosis occurring ln oanleal patches about tho respirntory bronchlolos. During this exposure the peripheral alvaoll were not Involved, Tho partlculoto oloments in the dust wore transported through tho lymphatla system to the bronchial nodes, causing no significant reaction in either site; the fibrous alonents reasoned fixed et tho points of original local-- - - lzatlon and wore seldom dotocted In the lymph nodes, . After exposuro of approximately a year, a small amount of collular reaction had been produced about many respiratory bronchioles (fig, 4), As more dust was inhaled, it continued to accumulate in the same location and later stages of tho dlseaso (fig. 5) consisted of extensions of tho original lotions. Apparontly, tho inhaled fibers ware oaught in tho pooket-llke alveoli that are given off frun the lateral walls of the respiratory bronchioles;. There they ware phegooytixod and many of thorn war* carried into the wall by migratory oella. Uononuoloar leuocoytoe attraoted to the trot oauaod on appreciable thtokening of the bronchioler wail. After 10. Pulton, W.D., Ilouts, R.L., Dooley, A. and Uathews, J.L.i Asbuetcais. Part I. Tho Collection end Counting of Asbestos Dust, Speo. Bull. 37, Penn. Lopt. of Labor and Iudustry, 1934. XT T L 16 month* * dolioate f11. rusts roado it* appearanoo. Tho procoa* evolvod gradually and tho numbor of fine Interoellular oollagenous fibers steadily Inareaoa<l. A*.tills flbroslt contracted, it partially olo**d and distorted tho alveoli, end trlth this change tho alveoli boaaaa linod with cuboidel cell*. Tlie roeult as an adenoian-llko appearance which freqiantly ao- co'cnanies chronic pulmonary Inflammation resulting from many cause*. * ll . * milis^*^ described a similar structure la the lung* of guinea pigs In haling silicon oarbldo. The longer exposure* to asbestos resulted only in mare thickening of tho walls of the air spaces, largely due to an increase in tho amount of flbrouls. Tho fibrous tissue always remained cellular end failed to show the hyallnisatioa oharaoteristlo of silicosis. Asbes- , tosls bodies (fig. S), first scon-in the lung* of the guinea pigs that ; had lnhalod duct for about 2 months, beoamo aura numerous end more dl t-- tloctly sogmontad with Increasing exposure. . Tho reaction produood in guinea pigs exposed for 6 and 9 months did not progress significantly during a subsequent porlod of 3S and 37 months when the animals lived In a normal atooophoro (figs. G end 7). Botweeo 8 and 11 months after exposure ceased, the cellular roaotlon In the lung had been completely replaced by thin strands of fibrous tissue. At * . | . * '* ' * e ' later periods, the sear tissue wae lose In amount but In tho last animal sacriflood, 37 months after discontinuing dust expoeuro, some fibrosis was still vlalblo. I10 10. mills, n.S. and Brutaaert, P.i Tuaor-llks Structures in tha Lunge of Guinea Pigs Artificially Exposed to Silica Oust. Am. Sov. Tuboro. 17i ZC8, 1920. ;' c- Reaction i n Oulnoe i*i |. Infootod with Tuberolc Bacilli at the Onaot of Quit Inhalation. Of tho croup of 40 guinea pigs Infootod with at ... x teuustod tuberclo baoilli, Rj attaintat tho tins that exposure to dust vas begun, 31 diod or were eaorl flood bo for# tho comp lotion of two . yoaro of duat expoauro and wora roportod la tho papor by Gardner and Cummlngst^), Seventeen of thoae diod from Intarcurront pneumonia. Briaf- . lyp the resulta were ai followai 10 revealed aome evidence of eproad of tho tubercuiouc prooeaa (fig. 0) in 6 of theaa It was confined to the lunga and In the other 4 the abdominal vtaeera alao were involved. Ex - tension of the Infoetion was first seen after 7 months of duat inhala tion} during the next 20 months more than half of tho animals shoved on -- activoly spreading tuborculosie and in 3 of them email cavities had ds- .. __ veloped. Our It. the last 8 months no animals exhibited any evideaco .of active lnfoctic-n although in half of then tho hoaled fibrous soars of previous spreedo wore obvious. The soars wore more extensive than is characteristic of either tuberoulools or asbeatoals alone. \> Tho 0 an Inal o which wore still alive after two years of duat expo sure were sacrificed at'intervala during the following year. In 4 of thorn the primary fool of infaotlon woro healsd with fibrosis and ovan oalol- flcatlon and thoro was no evidence of progression (fig. 9). In the other 6 the tuberoulous foci shoved evidence of having previouoly spread IooaIIji in 4 of thorn, by the time of autopsy, tho foci wore healed, with oxceo- olr'e fibrosisi in the remaining animal there wne a generalised chronic tuberculous pnr.umoaia in one lobe and in the other lobea there were iso- . la tod primary tuberolos, which vere still aotlva but had not spread, "x " ~ 1-t. stoenken, Jr, and Gardnar, L,U, Am, Hev, 'jubero, i4i 61, 1940^ " Strain or Tuberelo Uaalllus, could bo found, usually li'side cells. Some of the flnnst Intracellular particles war* surrounded by yellow deposits having tho save oolor |j^tho ssbeetosis body. Fzpouure of ons year had porsittod on accumulation of stony lonpor .floors, s nuwbor of which were coated and soan aa typical . eebeetosls bodice. Uost of these were still chart enough to be partially or entirely within phagocytic cells. By the 20th nonth end thoresftor they wore relatively numerous although still rare In comparison with the findings in tho King's floats experiment. P oactlon In T<hito' Rata. fb/venty-throe white rata noro exponc^to atmospheric ohtrt-fibor asbestos duat for porloda up to 52 months. Searlflolngo during tho first 10 nonths worn mode blnauthly and for tho re mainder of tho sxporlwmt at lens frequent Intorrals. tip to 6 months tho duut nulls were widely scattered and axletod In foci only sporadically, Rouctlon was limited to occasional alight thickenings of the septa i^put email ecciunulotlnno of duat cells. In a few rats at 10 months, there was * ouggoatlcn of oarly flbroala hut the change was eo slight that it would probably have boon overlooked without tho clutio of dust calls which at tracted attention to tho area. Only 10 aniu-nla wore oxporod from 12 to 32 months. In each of thoai tho lunge showed minute foci of. wll-doflnod . fibrosis distributed like that of asbsetosln but without snbcstoals bodlei Tho lesions, visible only at a r.*n^nlflection of 160 dlnrccfccra or nor; con sisted of pntch--o nlorjp nlvcolnr dueta In which the wells of tho aca* moi.<ted nJr aniirim worn vnry thick, dm* to swollen collagen frorv.ef.orfcSc Connoctivo tlnr.uc nd Foot-Rlelochoerkl sllvor proparntlons revealed com plete Ice.-; of crnl llsry bod locally. Outnldo tho collagen was a thin -19- T c r. r layer of epithelial colic. Thl* did not reeemblo tho "adenoaatold" ohaoge chnrootoriotic of guinoe pig aabestosia. Rear tho loolono tl air opaaot worn fillod with phagocytes containing gray to yellow pagbloulato dust and a rare, long, naked oabostos fiber. Careful search fallod to reveal ovon a suggestion of an asbostoals body, Plourley was absent. Ilia tracheobronchial'nodes showed compact focal collections of monocytic cells at 12 months and, at 20 months, some diffuse thickening of tho rotleulu:a. In a fsw rats thore was definite fibrosis along tho margins of tho nada and extending into the medlastinsl areolar tissue. Results of chemical analyses mado on the white rate are givenj table 7 and the average value a have been tabulated In table 8 for eoa parison with dollar valuoa for rats Inhaling other dusts It will be . . r notod that tho values for asboatos are lower then thoso for quarts or \ chart but approximate thooo for the gypaura-quortt mixture, in whlchjgst- moopberlc agglutination tended to reduoe the amount of dust inhalodv This condition prevailed evon though the atinosphorle concentration of as . that bootos dust woe essentially tho sane aa/for tho quartz, was one-hslf that for tho gyp sum-quartz mixture, and was one-fifth that for tho fer ruginous ohort. SLnoo the valuos for aeboatoa aro layit might be in- ferrsd that the total quantity of that dust aetually inhaled was azsall or that it had boon ellninatod from or dissolved within the lungs, Evalu ation of those possibilities is not foaslblo on tits basis of tho obser vations derivod from this study. & gar Roaotlon In Cats. Twonty oats were usod in this inhalation sxpori- mont with the chort-fibor asbestos, Eighteen were Vept in tie dust room t -20 Jj*' T c r( r continuously, until aaoilti.iod, tho exposure period ranging from one mouth to nearly. 54 months. Tho other two were.romovod to normal .w after a duet exposuro of 31 months} one of those was Saiccrrififiioceed S5 montths. am! the other '.'A mantho, later. In general, the tissue response ni con* fined to microscopic fool of fibrosis in tho vails of groups of subpleural alveoli, rather than in the peribronchiolar areas. In one animal the chango was extensive enough to be visualised on gross lnspsction of the section. Only in tho animal vith tho longest exposure^-54 montho^-did throughout both lungs. At autopsy, 9 months later, there vaa only micro-- sooplo fibroein in the subpleural cone plus hoavy lymphocytic Inflltra- . v*was ft %ase is a v* /*iaaue wwuaS| wiwuuit U4M vjivu w itauvvi o **wue vero found in two animals exposed for moro than a year. . - Reaction in Rabbits. Eight rabbits voro expocsd to dust for periods extending from one to more than five years| the last animal was removed from tho duat room and left In normal air 6 months bofore being ssortflood. There vaa naver enough pulmonary flbroaia to bo dotoeted.grossly and.there was no chronlo adhesive pleurisy. Vlorosooplo evidence of alveolar wall thickening was first detected In one animal after about 3 years of expo- four years of exposure, exhibited a reaction visible oo gross inspection of tissue eeotloris. Tho possibility of pulmonary infootlon In this -21- a> ( animal could not bo oxcluucd. In another animal dying two yoars later the focal fibrosis woe not nearly as obvious or as advanced. Areaagrf Involvement, which wore largely visualized beoause of phagocytic r reac tion within the air apacoa, tsndod Bicroscopically to besoms more fi brous with the.passage of time but there was never much encroachment upon tho lumen of dir spaces and tho arohiteature of tho lung was pre served. Asbestooia bodies were not doteoted In rabbits that died osrly In the experiment, but were seen in all animals that had been exposed to the dust for moro than throe years. Summary and Interpretation of Inhalation Experiment with .Short-fiber Aebesfcos Duet. The original purpose of the experiment was to evaluate the rolo of short asbostos fibers In the pathogenesis of asbostosls. It Colt alco that if the tissue reaction to short-fiber asbestos wof* more rapid and mors extensive than to Xing'6 floats there would thaJ^&e `I bests for believing that tho action of asbestos Is In part, at least, a chemical ono n postulated for quartz. This oxperlment, in ?&leh the tis sue rosctLon vro s slower end loos extensive than that in the previous ' experiment with Xing's floats dust, Indloatea that tho capacity of in haled asboctoo fibers to produoo fibrosis is dotsrmined primarily by fae- tors not chomlcal in nature. . Of tho four spoeles exposed in this experiment only tho gulnoa pig and to e losser oxtent tho mhito rat responded with characteristic peri bronchiolar fibrosis. Tho cat raaoted with atypical sub pleural fibroma . I ... ... * . *. and tho rabbit with only slight paronehymal fibrosis. j0T J? / \r- i UALL-HILLYD 15DESTUS CUM Ia the inhalation experiment with abort-fiber asbestos dust a SqjTja. ll quantity of unground short-fibor asbestos eras nixed with the ball-tallied . product In order to generate a suitable dust olaud. VHen that oxperiaent failed to produce in aooelorctod tissue reaotlon, la Casparlsoa with the response initiated by King's floats, it beoaao apparent that the biolo gical activity of ssbaetos is not increased by reduction in also of the fibers. Thua Llie possibility arose that tha tissue reaction observed sat due oolely to tho relatively few long fibera In the unground aabeatJ^j~- snd that the short fibers of asbestos had no nore than a very inolgnt-- fleant role in tho production of asbestosis, a conoapt not in accord with provloua experiments concerning pneuaioconiosia. Consequently another inhaletinn experiment was started In which only ball-milled asbostosgas usad. CoCTposltlf.n end Atnonphcrlo Concentration of the IXiat. The dusting natorl.nl was the bnll-mllled short-fiber aobostoa uaod in tho previous inhalation experiment but usground material was not mixed with it. Owing to tho tendecoy of the material to form email spherules which prevented muoh of the fibrous portion from floating out of tho dusting maohino, the dispersal of tha dust was not ontirely satisfactory. Therefore, after on initial 7 months of operation, stool wire brushes wero attaohod to tho * inside ourfuco of tho hoppor and to the rotating paddla to diolntegrs^ tha spherules r.nd release tho fibers. This arrangement gave satisfactory results and wan used for tho remaining 21 months of the experiment. The t J* T c composition. of the ran babtstoo used la shown 1b tables 2 and 3. ' .gag. Petrographic and X-ray <ttx*freotlon examination of atmospheric dual, r collected in tha dust rooo with an electrostatla precipitator after the installation of wire bruohoa, Indicated that about IS per cant of the alr-cuspended notorial was ehrysotilo and about 0 per oent, serpentine* of the balanco raagnotlte comprised 10 per oent, bruclta S per cent, _ quirts 2 per cent and other minerals 10 par oont. During tha 7-month parted before the wire bruahoe wore used tha chryeotlle oontent of tha atmospheric duet was somewhat lower than IS per oent but reliable ealfjaa wero not nbtalnod. Tho dust concentration far the first 7 months of the experiment was about 100 Bullion particles par oublo foot of air. After . the wire bruehoa ware installed, the duot counts were higher end the over all average for the remaining 21 monthe wee about 150 million. Slxo- fi* fr3quo"ey studies of dbeoaphorlo dust oolleoted In aide the eelnval cag<3t revealed that nearly* S3 per cent of tho components tuspendod In tho sir could bo olassifiod to olump a or perttolooj only* about 1 to 1.6 per oent was flbors. Or.c-third to one-half of tha fibers were longer than IQ latorona, Indicating a concentration of long fibers of about 0.8 million, about one-half the entimated mis figure is annwhaiXxXiuncsnzxsspBXArngxralue of 1.4 million for the ahert-flber experiment. Guinea plgt, rats and ni.ee were used in the inhalation experiment with the 1QQ par cent ball-mlllod aaboetos dust. Ihe rosults era ousmarlzed*. In table 9. Reaction in Gulooa Plga. Tha experiment was started wiHx 100 guises "Iga. Am tha dust exposure proceodod, thore ware 33 accidental deatha. -24- 7 r 32 of theoe being duo tv t'\nunonln in an epidemic. The 61 pigs remain- cept far Id guinea pigs troncferred to normal air after 28 months of dusting. For tho first yaar of exposure practlnally the only roaetlon to tho dust na the presence of scattered phagocytos and an occasional minute ssbea- tosls body. At 16 and 20 months no gross .response eras vlstblo pon the tissue section but microscopically peribronchiolar foci af inflammatory cells could be seen. At 24 months (fig. 10} there was still no change large enough to he seen with a bend Ions although microsooplc oxwmlajjfe" tlon repealed cellular accumulations about terminal bronchioles and many more aabestoeis bodies, chiefly within aella. .The{lungs of animals ex posed for the full dusting period of 23 months and afterwords living in normal air for 2 months revealed the changes described above and slso^yory slight peribronchiolar fibrosis. For exposed animals living 6 monthoStn normal air tho findings were similar but at 12 months 3 of 4 animals showed grosely-vldlbla characteristic peribronchiolar fibrosis with adonomatald change (fig. 'll). The tracheobronchial nodoc were essentially negnttvo until exposure had been oontlmiod for more than a year and a half, Animals sacrificed at 12 aonths and at 16 montha revealed a few minute collections of phagp -- cyt.ce containing partloloa but practically no fibers large eaoughc to be rocognliad AS (Moll. After 20 months of exposure many monocytea filled * . f&h with yellow granules were present. At 30 months thero had been a allgh*? increase In rotlauluia but no fibrosis. Ko furthor changes occurred In ' * tho nodes, Asbestos!s bodies wore not seen In the nodes of any of the gulnoa pigs. S*x -25 T si c. Minute aabestoaia to.it via nra obaervod In the lungs ea oarly ai 3 months iftor exposure began but thay did not beoome numerous untl^ fc 15 months had oltpaed. Tho todlos were short and practleally all were intracellular although at 0 months soma were long enough to project beyond the oall borders. It Is Important to note that in the later months of exposure there was a dlstlnot Increase In the number of long fibers, up to 70 microns In length,-In the lungs with the formation of characteristic long ashestosls bodtoo. Chemical analyses (table 10) of the lungs rareal that considerately Sr dust had been retained in the lungs.. After 24 months of continuous expc sure the average value for total silica, per oeat of ash, was 25.37. This should be contrasted with tho average value of 14.34 (table 6) for animals exposed 24 months to tho short-fiber ssbeatps dust. To view of tho high values for oillea obtainod for tho animals exposure to tho 100 per cent bnll-dllod dust. It la Important to note * that their pulr.onory ro op on so waa much leas than that In animals exposed % * far 24 earths tn tho short-fiber asbestos. This again lndloatoa that the biological activity of asbestos Inhaled into tho lung is not increased by raduetlon In slie of tho fibers. Posctlan in Wilts Rets and Mloe. In this experiment 40 rata were exposed for periods up to 20 months and 24 aico for periods up to 12 months. Neither species developed even a suggestion of asbestosis an^re; reaction was limited to phagocytosis of inhaled particles by widelyscattered dust colls which remained free in air spaoos or were transported -26- St c to the tracheobronchial lv. pfc nodes, No- asbostosin bodies wore found In the rate but In tho nice t'nore were a very few small non-haustra^SS forma within phagocytes. * . .. . 7! . Summary and Interpretation of Inhalation Experiment with 100 Per Cent Ball-telllmt Aabeatoe Duat. The tissue roaotion obaerred in thla ex periment was not aa intense as that in the previous investigation with short-fiber aabostoa. Tho reaction was slower in development and leas A' y\ & extonaive even though more duat accumulated in the lungs. Since there were fewer flbora longer than 3 microns in the material used in thlsjgjac- perlmont, the results tend to confirm the interpretation made in the sum mary of the ahort-fibor experiment that the reaetion is not primarily cheatool in nature, and to support the impression that roduotion la size of asbestos fibers doos not increase the biological'activity of aeboSSpa inlmlotl into ths lung. # The findlry* of long aobootoeia bodies in saimala that had lnhalod tho ball-milled suitorlai ia an example of tho difficulty of oonplotoly elim inating long fibers from a largo volume of asboctos as required for si Inhalation experiment. - In regard to progreaslon of the tissue reaction after removal of the animal a from- duut, which iraa observed in this experiment but not in the others, tho following interpretation lo offered! When tho reaetion is we11-dovoloped ct tho termination of exposure, tho contraction of the 'K&F brads.tiacue obcouros any progression that may have occurred} in thti experiment, however, since tho reaction observed was less mature. Its sub sequent progress *as mor readily apparent, * -27- r LOrffl-FIBEa ASUSSTOS DUCT Sino* inhalation of short-fiber and of 100 per oent ball-mille^ a shooto a dust did aot result in acceleration of the tissue raaotion la oenparlson tilth that produced by King's float*, the hypothesis that short fibers of esbostos were of minor importance la the etiology of asbestoals *sd givon added support and attention was dlrooted to the viuw that tha long fibers were of primary significance in that etiology. The King's floats asbestos used is the first inhalation experiment had a rather lev cor.tont of fibrous chryeotilo and contained considerable serpentine other impurities. Thorefcro, it wns decided to oonduot new inhale* tion oxpojleant with a puror fora of chrysotile which would be rloher in long flbern. . . r ComogaltioM and Atmospheric Concentration of the Dust. The dus g notorial employed in this investigation was obtained froa an asbestoe fabricating plant. Suaploe of several varieties of long-fiber asbestos dust were first submitted to the Saranao Laboratory for examination and one of thoce, which woe low in cognetlto and chromito end had a fibrous eontont estimated to be about 75 por cont, was colectod as moat suitable. Stool wire brushoe, fastened to the Inside aurfaoo of the hopper and to the rotating peddle, as in tho preceding inhalation oxporimont, were used . to opoo up the. bundles of asbestos and llborate more fibers into the atmosphero. Tho composition of the long-fiber aabostos ucod is indicated by the. chemical and petrographlo enalysos given In tables 2 and 8. Analysis of \ dee air-ouspartOnd material tho dust room dloclonod that about BO por cent of tho lang-flbcr duat vai ohrysotile and about 20 por oent, oeg- pentlno) it already noted, tho campooitloa of a similar air-flotted &am~ plu of boll-milled short-fiber dust wt\a 16 por oont chryaotllo and 60 por cent serpentine. Tho dust concentration as revealed by impinger samples tal.cn inside tho animal cages wei such lower than tho eonoontration for tho experiments with short-flbor or ball-milled dust. For tho first year of tha experiment with lor.g-fibor sobostoa the average of tho light* Hold counts was 32 million particles per oublo foot of air) for tho aocond year, 40 millioni for the third year, 39 millionj and .for tht^T fourth year, 43 million. Tho sire-frorjuonoy of ateospherio samples of the long-fibor nsbootos dust and of the ball-milled dust la shown in table 11. Doth aamplos woro collected with the electrostatic preclpits- tar. Tt will be noted that tharc was far more fibrous material In long-fiber dust. .. Guinea pigs, oats, rats end mloe wore employed in this Inhalation experiment. Tho roaults, summarized In table 12, are deoeribod in groatar dotall bolow. . Hanotion In Guinea Plgc. The experiment wao started with 100 guinea pigs. Aftor exposure had been carried on for a year, a severe spidoaic of pneumonia aroso In tho dust room and about ono-thlrd of the animala died ar were killed. To ..replace thorn, 30 more guinea pigs wore added to tho'survlvlng gruup. Histological examination rovealod losiona in the? lungs after 0 months of exposure to <Ajit, consisting of aellular connec tive tissue about the terminal bronchioles (fig, 12). At 12 monthf there were adonomntuLn changes In the sdjaoont parenchyiAai areas and by the (c r IGUi month ( fig. 13) a oji l-.lto fibrosis woo present in thooo areas mo wall to around tho bronchiole a. The fibrous laalon could bo aoea nvoroscoplcolly at 20 months. Proa thi* tima on tha reaction increased jjj . extent and In tho amount of aollagon and by tho 34th month, it hed fanned out considerably into the parenchyma (fLg, 14). Tho leaioni were rather sharply localised and tho oxtenaioos from different bronchioles showed no tendency to fuse, even in animals exposed far the mejciina period of 3 years. Although the intrapulmonary reaotloa sometimes reached the pleura, there w.is no Involvement of that membrane. Emphysema was not deloeted at any point.. Some thiokoning of the larger bronohi with chronla Inflammatory infiltration was revealed, but it was considered no .more than would bo produced by a similar .exposure to any dust. .. . . In guinea piga exposed to tho duet for 20 months and then removed to normal air, thcro *as a marked tandency for cellular Inflammatory heao-- tion to clear. This effect, accompanied by contraction of the fibrous tissue, resulted in a diminishing alee of the fooal lesions. Mono of these aninalo, killed at various periods up to 14 months after exposure, rovoaled loslani; aa large as those in .the group seerificed at the end of the 20-month oxjosure period or those in animals which remained in the dust room for sore than 20 months. Fourteen months after dust exposuro ceased, tho foci in 4 of tho 6 remaining guinea piga were so amall that thoy wore visible only with hand lens (fig. is). Reaotlon in tho group exposed for 2? months and then transfcrr^jL to a normal atnosphoro was quite similar to the response in the 20-aanlii exposure anlmaln mentioned above.. Small fool were aliraya visible on gross Inspection of ceotions of all guinea piga of the 27-month series, but in -30 T Is ( r Reaction In Culoca Pir-s Infected with Tuhorole Daollll eftor Establishment or Asbestoals. Twolra guinea pigs, after inhaling King's float* aabeatoa dust for 26 months, wore infeotsd with tuberele bacilli and then ronoved to normal air. Six of these animals died within awa nooks, f1 "* from intereurrent non-tuberculous lnfeotlon. The romaintng -fljS' animals were sacrificed at intervals up to 14 nontha after Infno tion. The subploural tuborelos In the duetod animals were no more misa-- eroue than in non-duatad controls but a considerable number were found In tbo doptha of the lung about foal of aebostodi*. The tuberouloua component of tlio ooablned reaction showed only alight looel extension about lesions 1a the lungs and tracheobronchial lymph nodes. Caseation was found in tuboroles l-l/2 nontha old, but by 5-1/2 souths it had oompletoly dlsoppcured, leaving only soar tissue. Foci of fibrosis still persisted Is tho last animal, which was killed 14 months after infection. Reaction In Rabbits. Rabbits exposed to the asbestos duat for periods up. to 19 mouths developed a low-grade foreign-body type of reac tion but no fibrosis. Although their lungs contained particulate elementa of the dust, fibers were not present, indicating that the upper roapirstory meohanlsa of the rabbit Is adequate to exoludo fibrous forolgn- bodies. Two rabbits, suiter Inhaling duat for 6 and 19 months, lived in normal air' for more than t:w> yosrs. At autopsy nsithor animal showed any ovldonos of cellular reaction or fibrosis in the terminal bronohlolos nor wore ' thdre any aaboctosis bodies. Roaotlona in White Rats. All the rats had aoqulred an lnfeotlon, rs- -13- -f\ ft T i T /- f r suiting in tho foruatlot. ui pulmonary abcaossss, before they cut# to autopsy. Apparently, so sauoK h-iovy bbuoub obstructed tholr bronchi that vary Tow fibers could here entered their lunge. In a few of tho rata, an occasional asbcstosla body waa dicauvored but thara was no fibrosis. H>U phase of tho experiment woe ooneldorod unsuccessful. Summary and Interprotatl on of Inhalation Exporlnent urith King* a ` Floats Puat. Yhe findings in the experiment with King's floats dust can be awsaarized under two hoadinga. - . A. Effect of the lnhalod dust oo normal onlnrla. Tho Xing's floats dust caused a characteristic porlbronahlolar fibrosis in guinea pigs bUv not in rabbits or rats. The fibrosis did not increaae significantly In oxtont oftor tha dust exposure me discontinued. D. Effect of tho lnhalod duet on tuberculosis in guinoa pigs. In guinea plga In fee tod with attenuated tubercle bacilli and then plocod V5*. tho dust rooa, the results waro more variable than la usual in an experi ment of this tyuo, A fow animals ahonod no sign of progression of the Infection; in rest of them thero was orldonce of toiaporary progression with subsequent hauling; In one animal the tuboroulous proooaaremained .active to death. In contrast, when guinea plga, after boing infected,-.... are axposed to quarts dust instead of asbestos dust, tho Infectious pro cess continues to progress and eventually oauses tho death of tho enimala. On the other hand, expocuro of infected animals to a hamloas dust like Ir6.n-oxide dooa not lead to any progression of tho infection^^2)# Cuii^ja 12. Vorwnid, f.J., Pratt, P.C., Durian, T.U., Dolahont, A.R. and Bailey, C.A.i Sidorosls. A benign pneuoooonlosl Du to the inhalation of iron Uuat. Induat. Uod. and Surg. 19 170, lb60 -14- T c- ~\ pigs in feetod bltit attci\u-tjd tubercle baollll following tho termina tion of two year** exposura to asbestos dust did not dovolop progressive disease. Tho only ondlficatlon of tha infeati.aa woo la Its Localisation, a few bacilli being retained In the porlbronchlolar fibrouo tissue with tho formation of tubercles there in addition to the usual tubcrelos bo- noath tlio ploura. . In -rlew of the Tarlability la results, the unusual nature of tho response end the high preportion of deaths from iatorcurront pneuaonia, it la folt that only tentative conclusions as to the influence of aches* tos dust on the course of tuboroulous infection are Justified by th3^' experiment. '. \ I SI1.HIT-FI0SH ilSUhaTOt KJCT Since hazardous duets lib# quarts are most effoctivo in produe1^^ fibrosis when tho particles arc S microns and Ices In else, an Inhalation experiment was performed to do tanaina whether this oondltloa is true for afibeotos dust. It wae thought that a short-fiber aabostos dust consisting elmoat entirely of fibers and particles smaller than 3 microns mould initiate an accolorstod tissue response and produco an advanced reaction in a shorter time then did tho King's floats duet, which contained fibers Cron 1 aHUae .Or to 1 micron and loss in length ae well as such particu late matter. tT' " Compoalli-u sad Atmospheric Concentration of tha Uuct. The duserhg material for tlila experiment was tho romains of fibers oollooted la dust bins of an asboatos fabricating plant after a carding operation and -16- O.o c. r~ screened to pass 2CO mo..h, Since ths tutorial as rocelved oontalnod many long fibers, it was ground lo a steel ball mill to roduoe oelly all the particles to 3 microns or less Is. site. Yihen usod aloes In the standard dusting mschino, this finely-ground asbestos tended to paok in the hoppar and It became necessary to mix one volume of the un- grovmd materisl with throe volumes of the ground to ganerata a satis factory dust cloud. It is portiooat to asntlon horo that tho addition of tho snail quantity of unground asbestos was unfortunato beesuso it eon- fused tho interpretation of results. . Ths oonpoaltlon of tho short-flbar asbestos as received la diseSwsed by the chomlaal and petrographic analyses given in tables 2 and 3. Sam ples taken before and aftor grinding yielded about the sasto values os analysis, indicating that there us no contamination from tho alii or loss of water content. Tho dust concentration variod during tho mont, the llght-fiold counta for atmoephorio samples collootod inside the animal cages with the Lopingcr apparatus ranging from 03 million to 182 million. Tho average of counba was 130 mLlllon for the first year of tho experiment, 134 tail lion for tho second yoar and 140 million for tho third year. Slze-frcquoncy measurements of air-floated dust from loaldo tho oanas st a magnification of 1300X revealod a great preponderance of fino porttolos, nearly 90 per cont of the particles seen being smaller than 3 It wfia oa Una tod tttat approxlrratoly-1 per cent microns. dpiprsxdxmLtelpx&cpsrxscnt of tho dust was In the form of fibers j gmator than 10 iniorono in length. Four spsoios of animals - guinea pigs, white rats, oate end rabbits - wore usod in this experiment. The ro'aults of the dust exposure, summar ised in table 5, are presented in greater detail bolow. * i -16- Reaction in Ciinct\ Plyn. Eighty gninnn pigs worn orlglntilly I bo duo to Intercurrent uppor respiratory infection. Of tho other 59 anionic, 46 remained in tho duot room until they varo sscrl flood or dlod at periods up tu 31 months and 13 animals were transferred to normal air oftor fading oxi>oood to the dust for 20 months. The type of tissue roactlon to the inhaled short-fiber asbestos was essentially the same ns that already observed in the experiment with_ Xing's floutn nohastos. The rato of rosctlon also sms npproximatolySths same, but the extent of Involvement with the short-fiber dust was very ouch less. After 1G to 24 mouths of exposure only .a very few email fpel of reaction, vMch generally requirod microscopic examination for detec tion, were producod in tho guinea pigs. Only after exposures had continued for approximately one year was there an appreciable' tendency for duat-eontaininji phagocytos to gather into clumps, hy 16 months phagocytos had collected about tho walls of a fmr of the rorplratory bronchioles with a little proliferation or Infil tration of monmualofir oells in those mills. Thero were also some multl- . . . .. ' nucleated oells but they were of the Inert foreign-body typs. ' At 20 tbol 24 months the cellular clumps were sometimes quite markod and sometimes ohonres io the epithelium rooulted in the odonooa-liko or "adenomatoid" appearance (fig. 5) prorlouely described in tho eootloa reviewing th<jjfntel-> oxperlmont wiU. the King's floats dust. In most of tho aubsoqueat members of tho aeries, the reaction remained osllular, but a few oxhlbltad pro- < r noun cod development of M'uo.us tissuo. In those fow, tho collagen way pala in oolor and tonuoua with no hoaTy swollen hyallnlration. * fuse chronic pleurisy without evidence of pulmonary infection was Dif- eent in a fow animals. Thin suggests that pleurisy nay bo a specifia concomitant of ashai'tonls, hut tho avldenao is not adequate to establish this point, lho reaction in the traehoobronehial lymph nodes ms nora pronouneod than in tho previous oxporiracr.t with ling* a floats asbestos, probably because of the" transportation of more fine pertieloa to tho nodes In animals inhaling shert-fibor asbostos. Tho nodal reaction was essentially an lncroase in reticulum, rather than fibrosis, with, aarvation of U.u original colls between tho thickened retioular fibers. In tho other group runovad to normal sir.following 20 months* ex posure to duat, progression of disoaso was not definitely demonstrated but neither could it bo absolutely disproved, owing to tho vsriablUJty of the* rocponco in different animals. ..The reactions from mild to csvora oocurred sporadically and boro no relationship to tho length of time af ter cessation of exposure. The differences wero attributed to variation in individual nusceptibility. Tills view rocolved support from the choral- cel analyses (table 8), which revealod comparable amounts of a?h and silica In lungs with widely different amounts of tissuo change. For example, tho arli and silica values wero quite similar for throe animals In dust 20 months and then in normal air for 14 months, yet the tissuo reaction for one animal was eoveroi for another, mild; and for thojjfiiird, only doubtful. ... . . ^ The formation of aabostosis bodies within bath groups was at first extronoly llmltod. Aftor S months' exposure "only a very rare short body -in- r no instance aa there evlu.wice or the reaction. Reaction In the traohoobronobial lymph nodes ira first visible ' i. the third month of exposure. By the Oth month, patchoa of cellular eon- . ' ncctive tissue began to appaar in the medulla and by the 14th month moat of the node had beoa replaoed by eollular oonneotlTO tiaaue, Thla plo- ture, which rasoablod that in .oarly allicoaia, persisted to the ond of . the experiment. Como animal o, o a variant,. showed hoary sheet a of dif fuse monocytes and large active giant oells but there mas never any necrosis or hyaline formation. The spindle-shaped new oalls were yelj^w- ish in color from fine pigment grenuloe that stained for iron. No fibers or aebestosla bod 1 os wore seen. .< Although aabestoala bodios were found la the lung aa early as one ... month after exposure began, they ware rare and hard to find. At S months more were vleiblo, chiefly oolled insldo giant oells, ond at 8 months^" many bodios wro free in oanaootlve tissue..- They became fairly abundant aa exposure oootlnued although in some later animals the acboctosls bodles ware only moderately numerous. ` It is important to noto from anolyooa of the lungs (table 13) that oven though tho tlsauo response at any given period of tlao was much greater In the guinea pig* of this experiment than in those exposed to olther short-fiber or ball-milled asbeetoa, the amount of mineral mattor In the lung ash wae much loas. ' . _ Reaction In Cato, Four cats inhalod the long-fiber aebostoa dust for periods of 14, 25, 33 and 42 months, respectively, and were immediately sacrificed. Two othor oats, after boing exposed to dust for 18 months. -31- dfc (Jf- lived in a normal aiaoai n-r.i for an additional 24 months. Erponuro for 14 months wee uufflolont 1.0 produos cellular accumulations of phagoggjtps around terminal bronohloloa snd peripheral arterioles togethor with ooa- pact collections of sloilar cells in the tracheobronchial lymph nodes. At that time thora wore no typical esbestosis bodl00, but smooth, polntod, yellow fibors wore soeo eery raroly. With continued oxposure, up to 42 monthe, reaction Ln the locationo noted progressed to tho formation of cellular oonnoctlve tissue which made well-defined sheaths about the respiratory bronchioles and arterioles, marked lymphoid hyperplasia id lymphoid lnflllvatlcn of bronchiolar vails (fig. 10). fypieal aobcStasis bodies wero not formed although there was art occasional fiber, ssuetli, yellow end poinlod. Pleurisy was not preaont. The roaotlonwas similar in location to t-hat In tho guinea pigs, but fibrosis was muoh slower in do/olopuont. li'.xintgenograms of cats made after exposure -periods of 33 and 42 aontlu, roapootively, failed to. demonstrato evidence of pul monary pathology. ' . Hoaction In Kata. Although 20 rats were placed In the duo t room, many died from pnouiuonia and were not euiteblo for otudy. Five animale, of which one was oxpooad for 19 months and four for.- 25 months, were free from pulmonary Infection and offer a basis for tentative oonolueloas. In the 19 -months an Irani, the roaotlon was Just beginning. All four animals eaarifload at 2f> months showed n well-marked peribronchiolar fibrosis**, . w' AfZor a long soaroh only two umall smooth aahostoals bodloo wore foundr . * \ . In the 19-month 0 animal and nono was found In the 25-oonths animal. Thua thooo animals exhibited fibrosis without aobostosla bodies or flbrocl;3 accompanied by only a very Infrequent asbestoels body. noaction t;i LM.co. Out of 20 white nice used in thle experiment, 11 lived a yoar or more in dust and died or were sacrificed without showing on appreciable dogroe of pulmonary infeotion, Tho reaction to the Ea- halod dust was Halted to phagocytasio by mononuclear colls. Usually those were widely scattored through tho air spaces; a limited number wore grouped about tho torminal biunahloles producing some thickening of their walla. Thore r.rts no suggestion of fibrosis. . t'uuoroua sebnstosis bodio-s wore observed in animals killed late in tho experimont. Thus, those animals oxhlbltod aabestosls bodies without fibrosis. Smonary and Interpretation of Inhalation Experiaait with Long-Fiber Aaboatoa Dust. Tho purpose of this experiment was to ovaluato the Impor tance of long fibers in tho tlssuo reaponee to inhaled asbeatos. The roaults. In comparison with previous investigations, indicate strong that long fiberu are ohlefly responsible for aeboatoais. Thus, tho raatlon in guinea pigs dovelopod earlier and became more oxtansivo in thla exporimont- than in previous exporlmonts in spite of a oanller con centration af aUtosphoria dust and a lowor mineral content of tho lungs. Purthormoro, a typical peribronchiolar fibrosis was produced in cats al though in a previous experiment with uhort-flbcr dust porlbronchlolar filironls dLd not dovwlop in thin spooiea. Tho causo of tho cellular fibrosis in the lymph nudes of tin guinea ' pig's la not clear. It did not occur In other inhalation exporimoutjS^with asbeatos. . \ -35- T r6 I t! J B i, 7 t 0 H EXPERIUEHS Sine tho Inhalation exporLmeate reported bov atrongly *u;&es,tod that long fiber* of anbestos are the significant factor in tho etiology of aohcetoais, a eoriea of injeotlon oxperlmonta was inaugurated wherein tho dosage and length of tho flbore oould be oontrolled more precisely. Also, by using controlled dosages, the relatIt* oapaclty of Tarlous aa- 7 / <r. (j ' boatoe mineral* to produce reaction could be compared. In these injec tion experiments guinea pigs, rabbita, rate and doge wore ueed and the the tf&L mineral duet tub. injected by the lntratraahaal,/intraporltoaoal ond/aS- travonoua technique/, but not all the techniques were uaod Cor each spoelos. For the purpoae of aimplifl cation the findinga in each aeries of testa, except for dogs, hare been condensed and reported in tables, 1- i to which roforotne will bo mada later. In tho case of dogs, only on- teat waa made rind since tho findings were negative no detailed report la included. EXTEUIUEhTS USInU Tl.TUATJtACUKAL TECHJ5IQ08 Ao the soio'fltno Minerals do not aauao a typioal adwanaod fibrosis . In extra-pulmonary tissue, tho intratracheal toohniquo is tho preferred way of introducing fibrous dust into tho experimental animal. In this method the duat suspension la lnjectod by moans of a apodal noodle or oathotor dc-n .into tho traction, from which it flows into tho lungs. 5J -Si 's . 'h fe Comcarlaon of Flbrn..i: t.nil i'on-flbroil Du at a. To demonstrate that * the ability of aobeatoa to produoo fibronla i-osidoe in lta fibrous - character, tlio-oorlao of Injcotion exporlironta reported In table 14 yoro porformed. Tho toata were modo with unhoatod long-fiber ehryootilo and with chryeotlla that had bean Ignited to deatroy Lta flexible atruoture or ball-milled to reduco the length of fiber to 3 alarona and leae. At tho aame time fccntrol toata were made with aorpentlao, which has the I same choaical earpoeitlon so chryeotlle but la nan-fibrous. L review of tho findings reveal a that only the unboated long-fiber ebryaotlle pro duced typical p-irlbronohiolar fibrosis and that xcemd-ball-allied arterial containing only fibers leas then S niorons in length failed to oause fl-- broale (fig* 17, IS, 19). Flbora subjooted to Ignition also had lost . tholr onpaolty to cause aorioua. tiaaue damngo. Ignition produced lapor-- . tout changes in the chryaotllo flbora, among then being loss of wator, on alteration from a flexible to a brittle structure and possibly othoaf . ohangoa. Exporl r.ontal studies ooncoming this observation trill be reported ; / in a eeparato publication. ' '' Co'itnarlaon of Varloue Loniy-flbor Dueto. Soma vory interesting find ings are disclosed by tho rosulta of the oxporlmonta ruaorded in table lb. First, all the long-fiber aaboetoa minorala teatod, with the exooption of anthophylllto, produced a typical fibrosis. Tha oharactsriatlo peri bronchiolar reaction caused by threa roprosontativo long-fiber nabastes ainorala - chrynotllo, emoelte und orocldolito - is shown In figs. 15-y 20 -' ' `bP cod 21. It la not entirely olo&r why onthophylllte behaved differently from the other anbojitas minerals. -35- & Second, with tha nlnci-1 brucito, which is not a silicate but la a fibrous fora of magnoslum hydroxide, a characteristic fibrosis Ilka "that produced by the asboatos minerals was obtaiaad (fig. 22). . laoa tha.,.. bruclta used con tain ad only 0.90 por coot silica, ae an Impurity, it la obvloua that a uliicuous cooponont Is not an sasoctlal factor is tho dovolopnont of nabsstools. ' Third, no flbrosia resulted from tho injection of glass wool flbors (fig. 23), o?on though glass wool reaomblot aobostoa in many ways. How* oYor, there arc fundamental dlfforenoos. A glass wool fibor 3 micron^. In dlumotor la a solid rod^ and, In short lengths, is fairly rigid, while an aebestoa fibor of the aaao dioaetor is a bundle of extremely fine fllaments which Impart to tho fibor a high degree of flexibility* It would Boon that this a true turn and tho associated flexibility are impor tant factors governing tho capacity of a mineral to produco peribronehio- lar flbraaLa. Experimental studies concerning thla observation will be roportod In a separate publication. * Comparison of hong-fiber and Short-fiber Dusts, Ylth quartx dust it has boon domonetrated that the smaller the partiolas, tho more Intooso is tho tissue roaction, and that there is little reaotiou-to partLolea lar--. ger than 3 mlcroaa in diameter. In the ease of asbestos, howver, the roveroo la true out) apparently only long fiboru hevo any specific effuot, 04 veil suggested by tho Inhalation experiments. Tilts la confirmed bj t^^ da.'bia of tablo Id, in which a aorius of toots with fibrous minorals is V .. rc;.ortod. Rheti tho Injected duct couslstsd of flbors 20 to 60 microns 'long, all tho fibrous minerals tostod, exoept onthophylllto, as noted In -36- c tli* proceding auction, pi-i.-iuced a fibrosisj whan tho material vaa pro- parod by first grinding tho fibrous dust until tho length of flbara was roduood to 20 aiorona and Iocs or, in aoraa caaoo, to 3 reiorans arid ffias. nouo of tho iiij'iclod dusts canned fibrosis. if These results differ from those of King, at al,(^) who report tho production of rutlculoals comparable with tho experimental silicotic nod ule In rabbits racaLving monthly intratraoheql Injoctlons of 100 mg, of lihodaalaA asbestos flbors, IS mlarons long, and the production of dlffuao interstitial flbroals in rabbits similarly injootsd with short .fibers, 2.li microns in length, T>o halieve this dose, aopaoislly in tho lonj^fcona rabbits, la highly oxeossivo. In our experiments the dosage ns kept loir in order to minlaiLze untoward reactions whioh might obsaure tho peribron chiolar typo of fibrosis which characterises early human asbestoals, EKPBtzums usi;:g iktuavejious technique The oxporlr:onta, sunmarl cod in table 17, in idiich the intravenous mothod of injection wae omployod, choir that tho asboetos mineralu are far dii'foront from quarts in their notion on tissue. It hso boon r epeatedly demonstrated thnt lntraronoua injeotlon of quarts partloles 3 microna and Iocs in diameter will cause a typical tlesuo reaotlon with the develop ment of hyalinieod fibrotic lesions in ertra-pulnonery sites, such as tho liver and tho spleen. Asboctaa minerals, howavor, on intravenous injec tion generally produce only an inort typo of reaction, as is rovaalffd by --^ 14 . [. 1-2, Xing, E.J., Clegg, J,T. and P.a^ V.V.i Effoct of Asbostoa, and of Asbestos and Aluminum, on Lunga of Rabbits. Thorax It 188 (Sept.) 194G. Abetr. in Indust. Oyg, Digest Hi Mo. 234 (Fell.) 1947. -37- ho * T X ( & tho results glvrn in tha u.l.lo. Tho reason for the early doutho in the experiment with chrysolite particles is not clour. EXTERItfEVTS OSIh'C INTRAPEOITOilEAL TECUKTQUE Thu result.** of injection axperimonta with tho introperitoneal toch- . uL:,uo aru given In table 113. It will be noted that tho long-fibur duota . prnducod a fibrous reaction while duals aonpoasd of particles 3 microns and loos in ulso caused only au inert typo of response. These exporlnuuts inuioata also that tho fibrosis initiated by tho irritation of usbostos fibers io not ros trie ted to tho lungs, as /was formerly assumed, button be produood in tho porLtoneura as well. * o t it s r b x : e n i u e m T. r* n it n asbestos kineuals A uuubor of additional oxperlmcnta w*ro conducted to throw raardrlight I on apscific phnsos of tho asbostosls problem. . rnoTCCTivK acticij o? alum mrv cou?ouwjs Intratracheal Injoction into a aorias of rats of a suspension of long *- a* fiber chrysotllo to which oolloidal aluminum hydroxide had boon addod revealed that tho addition of the almlnua compound did not provont the tissue lrritatin;* produced by chrys9.tilvic ,If anything, the aauto inflam matory response to tho injoctnd fibrous jaineral was aceeleratod. 0$3t. month aftor tlio last Injection of tho dust suspension the branohloLliiitis . T/as becoming fibrous. King and his asaoolatoa also found that nlumlatra 30 i\j A- & c failed to protoot pulcaoaa/ tissue from tho Irritation oausod by aobee- ,i eg. toe flberel"/| la their experiments metallic aluminum instoad of tbUr^ hydroxide x-ae used, . . -. . . FORKATIO*' OF AS?.i:ST0SI3 BODIES Tho iron is tho coating of the asbeetosis body appears to be derived from blood or tissue elements ond not, as has been suggested, from the mineral fiber. Following subcutaneous Injection of tea kinds of chryso-- tilo Into the groin of guinea pigs - one kind containing 2 per cent the othor 0.2 per oent F02O3 - the aobeetosls bodies ware equally numer ous at both sites of lnjootlon and showed no difforeneo in their resotlon to Prussian blue, tho raagent which stains Iron. This finding is in . agreement with that of Giroux^*'). TISSUE REACT IQ K TO ASGESTOSIS BODIES Intratracheal InjootLon into guinea pigs of asbostosie bodies re covered from huimn lung tissue failed to produeo a fibrous roactlon. The notorial for injection roa obtained by digesting with sodium hypochlorite solution tho lung tissue removed at autopsy from an asboatos worker. The axbestosis bodlse could boreoon In tho guinea pigs for at laatt a year after lajaotlau. This orperlnont shows that the asbaetoets body has a rather resistant casting which is not destroyed by moderate hypochlorite-^, treatment, which may bo maintained In vivo for a yoar or longor and vhicB* l? *- *$4. Giroux, M. Amlantoso experlmcnlalot Vsleur Pathognoaonlque du "oorps - DUmicnte". Level Uodioel Ut 3&, 1943. (. - c> * rondoro tho fibnr lnoapat<lu of producing flbroolo. It thus appear a that th coating is a protaoti.ro mechanism. Tills thought was expressed - i<i . ^3* by Belntker as oqrly as 1934^'^. . ... T HK' OUT OF IRRITANT ACTIO H Two hypotheses haro boon proposed to oxplaln tho tlssuo Irritation ' and reaction caused by asbestos fibers: the chemical and the maohanloal. In the ohonicel theory, which is based upon experience with quarts, it is asrumed that the asbestos ninorals diasolvs In the body fluids and tftat in this process their bases are leaohed away to leare siliea in f^na capable of irritating tissues. According to this hypothesis asbestosia would be merely an indirect, silioosis. Soreral facts make the chemical theory untonablc: introtrachoal Injection^ of bruoite fibers, which had a csilloa oontent of only 0,90 per oont, aaused a typical fibre ale ljj^e that produced by tho asbestos minerals: freo-sillca particles inoroase In pa tency as the particle alto becomes loes, but asbeotos fibers shortor than about 10 to 20 *itiorons arc relatively Innoauousj aluminum hydroxide neutrclltoa tho Irritating effect of quarts but not of aaboatoe; serpoatine hoa the sane choraloal composition as long-fiber chrysotlle but it pro-- ducod only an inert type of tleeuo reaction: there is a wido range In the chenlcal coapooltlon of tho minerals whloh do causo aflbostoiia (tablo 10), In view of thin ovldonco''lt eaaras raare likely that aabestoeia Is caused by on' unuoual mechanical irritation from long asbestos fibors, thloijgf l it, Bointker, li.i Uber die Asbostosi okorporchon. Benerkungea xu der Arbeit ron Begor. Virchows Arch, f, path. Anat. 293* 627, 1034. -40- T rs \ &F- Irritation being rolatad t:i tho peculiar fllamented atructure of tho fiber and the associated flexibility, which aro possessed by no other foreign body studied. Titus, lenition of ohryeotllo fibers ohangod ^Mir structure and made then inert although the a&ao fibers, before being heated, produced fibrosis (table It). Further support for the theory of mechanical irritation is that asbectosis oeours in an organ of high no bility - tha lung - and that a fibrous reaction can be produced by In jection of asbestos fibers into the peritoneum, whore there is also a ' degree of mobility, but not In other oxtrc-pulmanary organs such as the liver, op loon and subcutancoue tissue. . St * COUPLICATIODS . The experimental investigations with asbestos minorals wero con cerned primarily with the offoet of the dust on normal tissue but ola & attention vss given to othor phases, suoh as suaoeptlbllity to infection. Tho only experiment in which tho effect of asbestos dust on a pulmonary infection was studied was the first Inhalation exporinent, carried on with King's floats dust. It is unfortunato that, owing to the lack of adequate facilities at that time, infection studies oould not be mado in tho. other .. inhalation experiments alee. ' Suaceptlbillty to Tuberculous InfontIon. Tho development of a tuber culous process Initiated at tho beginning of exposure to dust, and also of a tuberculous infection superimposed upon an est&blishod ssbaatesia, was described in prcoodlng sections of this paper. It maybe stated that \ -41- T n> o (c asbestos, when classiflod according to tho effoat of a dust cm tuber culous infaction, would be placed bolow on aotivo dut like quart* 'i above an inert duat, such as iron oxide.1 In animals Infected with atteo- uated tuberolo hacLlli, quarts cousee tho infectioua process to progress until the animal dies of tuborculaais. Inert dust* hare no effoot on the infection and the losioos usually heal and the disease disappears. Asbestos dust is in a different category. In the experimental investi gation, when the fibrous dust was being inhaled during the evolution of tho lnfeotlon, thore was a spreading of tha tuberculous process for ^ time but usually tho stlaulus for continued proliferation of tha tubercle bacilli was not sustained, the progression was arrested end healing fol lowed. In guinea pigs lnfeated with attenuated tuberole baollll after ` ' completion of slightly more than two years of exposure to asbestos dust, progressive diooaso did not develop. The only modification of the iqgpe- #. ' tion was one of localization, a few bacilli'1 being retained in the fibrous terminal bronohlolea and forming tubercles thore in addition to tha usual foci beneath tho pleura. ' Suoh tubercles healed la a few months. Suoooptlbillty to Hon-tuborouloua InfootIon. Thore was no speciflo ' experiment concerning the effeot of Inhaled asbestos dust on non-tubaroulous infection. Intcrcurreot pneumonia among animals exposed to asbestos dust was rathor eosna-t^ tho froquoncy in guinea pigs exposed la the four in halation oxp orinert to ranging from 16 to 3D per eont. This iacidontalSvi- .y . w* donoo suggest a tlio possibility of an effect of asboetos dust on non-tubor- eulous lnfeotlon. Uoverthelosa, sinos suoh epldoalos are not uneonoa % -42 *r* T in Inhalation experiments ./Ith other dunts and oTon in tho colony of normal animals, It is felt tliut the inhalation of asbestos. dust doei^ot exert a significant offeot on tho susceptibility to noa-tuberouloue * pulxonary infection. . nrsCUSSIOU AMD S U U M A R I Owing to the Test anount of data laoludod in this investigation, it sc etna moat convenient to summarize and to state ae concisely as possible the vorloua obsorvatione which omergod from tha experiments and to low each with a brief resume' of the evidence. ' A. Various spoolos of animals, including the guinea pig, the rat and ths robbit, but not tho mouso, and the dog^ develop peribronchiolar fibroela of tho lung similar to human asbestosis, following tho in halation or the intratracheal lnleotion of long chryeotlle asbosWe fibers. ; . V : :..V. .. i ; ` . : . . Both Inhalation and lnjeotlon exporisonts provide ample support for thin statement. Figuro 14 rovesla the cellular fibrosis that follows inhalation of long-fiber nsbostos by guinea pigsj fig. 16 r? < shows tho fibrosis in the cot caused by inhalation of long-fiber asbestos dust. Similar but less extensive fibrosis occurred also- " in rats and rabbits (table l). Uioe and dogs failed to respond. ' This variation in response of different species to identical dust exposures is still to be accounted for. ^ B. Long asbootna fibers are essential in the production of the porl- bronehlaL flbroslai short fibers are lncapablo of producing this roaotion. .. ' Inhalation experiments with nsbeetos dust miggoat and lntra- <>s T c c''N trachoel injoction experiments oonfira that purtbronoliiolar fibrosis Ic produced by asbestos fibers between 20 and 50 nicrohj^ * In longth, but not by particles shorter than 20 nloroos (tables 16 and 18). Tills Indicates that the minimum length of fiber possess-* ing the capacity to produce tho typical poribronohlolar fibrosis In animals Is oosonhere batwoen 20 and GO nloroos. Pointed studies have not been oarrlod out to determine the upper ltsilt of ffoctlvo fiber length. It appoara, however, that that limit will bo determined V>y the inhalabllity of the fiber. Tho mode of action of tho long asbestos fiber in the production of asbestosis Is primarily mechanical rather than chemical in nature. The aridenoe for this conclusion has been reviewed la a pro* , coding section,t page 40. Tho flexible filanonteI d structure of as bostos fibers ployo an essential part In tho Irritating action, olnco tho solid lnfloxlblo fibers of glass wool do not produce fibrosis (fig. 23). . . . Typical experimental acboatosls was produced by the Inhalation of on atmoxphorla suspension containing an avarago of 133 million aebestoa particles per cubic foot of air by light-field oount, of which loss than 1 por cant consisted of fibers longer thax 10 mieroaa. . . .. ..... . . In the inhalation experiment with 100 per oent ball-allied as bestos dust containing O.G por oent of fibers Icmgor than 10 microns (table 11), a typical fibrosis was obtained (table 9), Tho evidoncfiS1' ,& presonted allows at least that on atmospheric concentration of aebos- tos dust containing loss than 1 million (0.6)C x 138 million} fibers, longer thou 10 microns, por ouble foot of air is oapsble of producing \ rf c. cxpericioutul aabcctoji, Li guinea plge. Tho actual lower Unit of coucuotrallof' of long fit-ore necessary to product* asbnstoain Ln animals canr.ot be establiahed from thesa studios. . E. Iho duration of exposure required to develop tho pulmonary reaction to liOieloi asbestos duet la inversoly proportional to the concen tration of long fitoro in tho atmosphere, vis., mm the eoaaontratlon is increased, the reaction dovolope ln shorter tins. The bnuia for this statement appoara in tho data of tho in-- halation cj-pcrinunt with lor-g-fibor asbestos. For that exporlisant tho uveregu uanoentration of tho otuosphorio dust was about 40 million pai tides por cubic foot of air and alia-frequency dotor-* mLnationo dlscloaod that 6,7 per cent of the air-suspended material consisted of fibers longer than 10 mlarcns (table ll). Thus, by... calculation it is cctir..atod that tho concentration of the longer fibero woo 2.7 million (G.72 x 'Omlllion). Tho lungs of cmlmala^ oxposod to the long-fiber aebestoa duet rorsnlod that tho pulmonary reaction dsvsleped La approximately one-half the exposure tine required for its development ln animals inhaling the bill-allied produot, for which tho concentration of the longer fibers mas only 0.0 million (0.6,t x 133 million). V' C(~' 'y`f 7. Established experimental aobestosls oonses to progress on dlsoontln. uing exposure to dust. The experimental ir.vcotlgation shows, in faot, that on dia-^g*. w Continuing exposure thors van on appreciable aleariug of tho mature pulmonary lnalons, due to contraction of the flbrotlo rcsotion. In contrast, cn irxnatu.ro tlecuo response consisting prlcicrlly of cells 1 -45- lJ cc vlth littlo or uo fiLi.-uiu continued to progroao. It La socumod tliAt following attainment of flbrotic maturity, tho name process '& of contraction would ensue as was notod for the nature lesion. G. Tho formation of aabcetosle badlos represents a coating cf tho fiber* by blood end tloouo demon tu, which resulta In loaa of ability of the flbor to produoo flbroola. Intratracheal injection of asbaatosla bodiea failed to produce the typical aabaototio tissue raaotion in experimental animalo. The consation of progreastro reaction to lnhalod asbestos duat soon af ter exposure torminatoa nay be due to the formation of aabeatoatp bodiea, H. Aluminum hydrosid o failod to neutralise the fibrosing-aatl on of the long-flbor asbestos, - Intratracheal injocilon of aluminum hydroxide with chrysotilo asbostoa did not retard or proYont the development of asbestosl^ in rats. . I. Inhalation of aabeotos dust did not altor significantly tho final out- couo of experimental tuberculosis in tr.o sorlos of guinea pigs exposed to the dust, - Tho apparently mild influonae of asbostos dust Is in distinot oontraat to tho stimulating effect of Inhaled quarts upoa a tuber culous procuss in the lung. The interpretation oust remain tenta tive, howovar, since It is based upon an invoctigotion United to / two sorloa of guinea pigs exposed to only one hind of asbestos^* namely, King's, floats. Reference to table 4 shows that vhen the lnfootlon was ooineidental with tl\o onset of dust exposuro, there t -46. \J & vna temporary progroealon of the infootloua procoaa with subse quent healing} when Infootion na initiated after 26 months of du*t * exposure the coura* of tho tuberculosis wag not approolably altorod.' Thla latter finding la quite different from our uaual experience with quartz duat or with mixed dusta containing quartz, wherein thj &<J- vsreo Influence of quarts upon a tuberouloua infoctlon la manlfoated moat strikingly whon Infection la initiated after period oftduzt oxpoaure, Tils., euporlmpoced upon a background of eatabliahad slli- coola. Ae indicated above, application of thla more sensitive tdEfc <19 ,*i; to eabottoc dut failed to demonstrate that aabaatoo had an advorso influence upon a tuberouloua infeotlan.i Tho inability of aabeetoa i duct in that exporlnont to affoot unfavorably the tuberouloua pro-^'^ ^j, S'" ' cess fnrniuhos strong cupport for tho interpretation ttiat inhaled _ 1 ^ ' ` asboctoo dust has no moro than a mildly unfavorable effect on Ja?> pulmoncry tuberculosis^ * `` ' Acknowledgment Acknowledgment la gratefully made to tho group of ooopanloa of the aabeetoa industry whoso generous financial oupport mnao thla investigation possible. -47-. (. ) <K c c & TAELS 1 ' RE1CTT0K TO LORG-FIBER CHRYSOTILE IM LOROS OF l!AK AHD OTHER SPECIES OF ANIUAL * Sooolflfl Ran Guinea Pig Rabbit Cat Rhito Rat Khlto Vouaa Dog lfodo of Exposure Inhalation . -' Fibrosis ' ' \+ Inhalation and lnjootion * *1 . * t mm m' m . Inhalation Injection 0 i 0 i Asbostosls Bodies Numoroua . - Mod. amorous t Rar and dBgplcoU. mm ^Vry raro Rare sad atyploal Mono f- . Tho aynbols 0 to 4* rofor to tho dogreo of tisauo roaotlon. / fi." TADLB 2 CHEillCAL ANALYSIS OF ASDZSTOS DUSTING UATCHIAL T King'* floats par coat sio2 29.32 Fjp3 A1S^3 C*#Z ) ) 8.84 ) VnO CaO 0.07 uo fc'a^O 36.66 *2 - . * m Ignition loss - 12.74 97.13 Shortribor par coat 37.17 9.09 1.40 0.14 0.09 0.06 55.96 ' 0.14 0.20 0.93 14.09 100.11 Longftbor par aant 30.40 5.52 0.78 *5 0.08 0.31 40.18 0.06 0.06 0.57 14.00 99.76 Not datarslnod CM OU \ tr IA TABLE 3 PETROGRAPHIC ANALYSTS OP ASBESTOS DUSTIl'G MATERIAL - King's floats Tlia approximate composition, baaed on partlolss (except ohrysotilo) smaller than 10 microns and reported aa parean- tages obtained from particle oounts, vaat ahrysotlle 14, serpentina 40, magnetite 12, carbonates 18, tala 12, other olnoral-j 4. For ohryaotlla, fibera up to 200 microns long wore included, m Short-fiber T}.a material aa reoeivod oontained a preponderance of fibrous ohryeotile and platy (non-fibrous) serpentine, ' Accessory minerals present vara doloeilte, ohromite, magne tite and a little tromolite and setlnollte,' The it*distributlon rmo nonunifora, Thore vere ooro fiber* in this material than In the King*a float*. Long-tlbor The material oontninod about 76 par coat of flbrou* aabeaton mlnoral, probably ohryeotilo, vlth oomo aorpontlne and small amount* of calelto, mngnotite and chloritio or mloaceoua mlnorala. A traoe of quarts was aeen, Thore wore shroda of non-oeparated flbor* 10 to 60 microns long and 6 to 16 aiarons In diameter. tC M * SWfiJART OF INHALATION EXPSIVKKT riT H fIS C 'S FLOATS ASBESTOS DOST Pi 9 F T K ith la < r-riru ls n t H^ s tr*A n o f tu b o ra la b a c lilu i A ftor lnfootlon. ft SUUyjlRY OF IHHALATIOH EXPERIHEET TTTTR SHORT-FIBER ASBESTOS y X t j i t f r f y & l ; D U S T M u * X C TJ 9 .0 H 4. . k9 a S'0 *9 4Q> 1 S3 o < us 9- uC O X4 fiuo. 8 %2 o o. te * Oa-t *3a o > on B *no t* n Po X . rx>-4 -a .8 s oo o.fa OI3O.i .4*ROO14 X+ X e u If a? p p.m TT ( TABLE XUALTSl'S OV un;c. ,.f GUINEA PIGS AFTER PROLONGED INHALATION 0? SHOTsT-FIBEB ASBESTOS &RLUST T f TABLE 7 ANALYSES 07 LU.VQS OF TO ITS RATS THAT HAD IlIHALKD SH0RT-F1DF3 ASBESTOS {tttrtjtTirtfrfDUST Amount of ash ()C of dried lung) # 0 nonthe per sent 3.9 4.3 2.9 3.6 3.3 3.9 3.4 2 months per oent 3.5 3.6 2.9 3.2 Duration of Exposure 4 monthn 6 months 6 months per oent por oent per cent 3.3 3.3 3.9 8.6 3.4 3.6 3.4 3.7 3.6 4.4 8.7 per oent 4.9 4.6 6.3 4.7 Total S102 (Jf of dried lung) 0.00 o.co 0.00 0.00 0.00 0.00 0.00 0.08 0.13 . 0.09 O.OS . Total S102 (/J of ash) .0.0 0.0 0.0 0.0 0.0 0.0 0.0 . 2.1 3.5 3.2 1.5 0.08 o.u 0.07 0.07 0.05 0.04 2.3 2.1 3.0 1.5 2.2 1.1 0.08 0.18 0.15 0.17 0.16 * & o.ia 0.15 0.15 0.13 2.2 3.8 5.5 3.3 3.4 2.8 4.0 2.8 4.2 * t/ormol dontrola (do dust exposure) I t D<d> c& TABLE 8 . COUPASISOH OP average values for ASH AMD TOTAL SILICA poa urcas of t,hit3 rats ihhalutg various ousts (Lungs only without included lysph nodes) j .Vacuat of Ash ' (JC of dried long) Short-flbor asbestos Quarts Forrugluoua chert Gypsun-quarts mixture Duration of Exposure 2 month* 4 months) 6 months ;8 months j 10 sonths per cent por sent per oentiper coot per cent ' 3.3 3.4 8.5 3.8 f*.9 4.3 4.5 7.1 4.6 f.8 6.9 8.9 9.9 9.0 14.1 2.9 3.8 3.4 3.6 4.1 ratal sio2 {% of dried lung) -- Short-fiber asbostos Quarts Ferruginous chert Cypsun-quarts mixture 0.09 O.S1 0.25 0.08 0.09 0.51 0.32 O.OT 0.05 2.94 3.45 0.11 .*jtal Si02 {$ of ash) Short-fiber asbestos Quarts . Farrugtuou* chert Gypruu-quac'tcclxtur^ \. ` 2.6 11.7 3.9 2.6 2.5 11.4 3.6 2.0 1.6 41.5 34.4 3.4 1 0.16 1.44 2,40 0.32 0.15 4.40 6.09 &20 & 3.9 20.4 26.6 3.2 56.6 43.2 6.7 1 gf 1 t;ic. 22 - Oruolto Injection exporitwut. Guinea pig injected lntratraohoallyj 4 aonths aCtar lajootlcm. Even with this nonsi liaeous fibrous mInoral thoro is peri bronchiolar accumulation of a oils and depoaltiou of collagen elallar to tliat flhanm in figs, 20 and 21, (200 X) <r\ a a q V ft TABUS 9 . SUUHARY CV IHUALATION SXPERIUEBT TVXTI1 100 PGl CEf.T BALL-UILLF.D A6BSST0S OUST ^ ; I Maxima Maximum : Survival Nature of | Humber of Dust , After Duart Experiment l Animals Exooeure i Bxposuro 1< Dust exposure! 84 g. pigs continuous throughout 40 rata Ilf . months i * 20 ! ; 11 i oantha 0 0 t 24 nice 12 i 0 i Rasults l .* Bo appreciable pulmonary reaction. Bo suggestion of aebestosiffl . . Ho suggestion of &sbesto*isa Dust ozpoaure fallowed by a lotigod rwsldonoe In nonsal air 16 E* pig3 t 1` 23 12 Fibrosis typical of aobostosis m pre- sent 12 nontha after exposure ceased in on amount eufflolont to bo<*Vl*lble grosslyi sailer foot ooulu be soon i- aroooopleclly at 2 souths and 8 nontbs/ after termination of exposure. % iCP re a o tio n , ranging from ' only w ith in th ia table group roprasant a o ra ly th r e la tiv e degree o f in th ia e x p e rla e u t). Thd ro la tio n a h ip a a p p ly ( V * H C) aID n fl * u cot o ^O CM ouI O*o U<0) u<o U) IS V) rM Q) CM cft st/j Mctoo 5o r 13 e Oa tCoO pCM A l* to to o a. CO 00 CM CM d t ^ o to o 4c*0* O^0- U H O U IQ to CHOM H^4 30 O CL tfl tf i o K 14 #* 4? CM CM O 4OCc* OOMCM talO) . Oa tn to Hw H o * 44C>>J to H w{3 C 09 o aH oO o o to* ^ c ft. loCOM . Cd R R tt* pao -p C O <n n n o rt to io o O *-ai o o4 &o0*4 U9 tfl IO nH oIOnn ooo mc a COM) HCM O -1 to to CM 4* CM CM to U> o> <n CHO 9C-Mt r<Ct-OMM Cf0CMM3l atCoO4m H t> N UJ W* t- 41 1 o o o 4* y oi" t* Vn to 90 o o <3 o a LOa to to to o 4-* ctia Ci in r, o cm CM O o U t'*o'to oin9 CJ *Ot +* 5 o icno ocO tioo H c taM M M e Fp wCM tioo e^* nq tf* o o o. .WOO), o COM% f^O HCO ooo OQH ot v o t 1<-M4 o 9N-4 OQN oo o CCMO tOo 4O0 w* ** o o and oannot b oooparod w ith sym bol* in o th e r t a b le t . re a ctio n in aach maxinun observed V c s o? cunrsA pig s exposed to dost in itk a la tio !; the tiaau to Z* (th in g le ) g b avera itle n a u o Wt a 3 ti -a u o 2c .3 0 frl 14 t. \\ * t) m >4 o *o 4> Cm 2 v; fl w 4 s. H "O CM ^4 o La w4 *0 CO V* #-4 O o Ow _ H_____ 4^ <*5 h d co it iM 0 d Ow c- ca o rt 4i q o a s n at k* O CO (4 CO *- i S d O 4> 2 u 3 fi-g !!: boli qua m( gy 1 Tbo 0 to TABLE 11 COMPARISON OF SIZE-FBEQUESCT OF ATMOSPHERIC LONG-FIBER AND 100 PER CENT BALL-MILLED ASBESTOS DUST COLLECTED INSIDE CAQES Grains ( < 3 nisroua ( ( 3-10 ( ( > 10 Fiborr ( < 10 ( ( > 10 Clunps Long-fiber par Qnt 66.4 u 0.0 25.8 6.7 1.0 Dall-ttlllod per sent 90.6 .e 0,0 0w# w8 0.6 3.2 (* TABLE 12 9 SimUAKT OF IlillALAIIOU EXPERIMENT . Kid LONG-?IDES ASDESTOS DOST | Maxima Woturo of ! Humber of | Dust Exporlngnt I Animal* iExnosuro months flint exposure 117 g, pigs 36 continuous ! throughout Ufa ti 4' oats i I i 20 rata 42 25 Maxima Surriral Aftor Duct Expo sum souths 0 ftosults Definite fibrosis la 16 months* Slowly dorsloping fibrosis first sesn at 24 months* . . Marked peribronchiolar fibrosis first seen at 24 Booths* 20 aioo 26 Linitod roaotioni no fibrosis* Hust exposure ( 12 g. pigs rollowed by a -irolongod . residenoo in normal air 9 g* pi,;.1! } 2 cats l is t 20 27 10 14 Clearing of inflammatory re^&tion and def inite contraction of fibro o4. Clearing of inflammatory raaotien end slight contraction of fibrosis. 24 Similar to continuous exposure group) sug gestion of progression in one of tho two animals. / \ TT "TTTt T ----------------------- i[ n <a r ^ o vi *> a Lv. i-o* C r CM /t t^n - A 14 4 O Cj -* o H CO 4 <n cm M* u' . . _ -a^ r-t VI m ji.i1 i; 4 0 r o to A to t- d Ul VI S;>: O .i St? 03 CM ft 3 O a ft * ,. ft . 00*.------ ft A Bcn Ul X n to ** oa o 2to WV.ua * c* 03 CO 1*) to ll t* M > CM 44 ooO m cm o tn cm ^ 44 fO* - r-4 <0 ft* fft * "* - ----.... -- - . 2ta w0) c eCM ftCM o WV 2 c* i 0 l> ** ft . ft. yt c*. r* U> to M* tn h 4 oo h o . .... ....H......H... . 4 CO .. 2g O . 8X 2* Co o -at4o _o o <ea u4 k VuOO4 ^-4Oo> tu u ( I 3 r. CM 4*f tn n SKIO Li 4* M Vl O vV *r lO O e cvi CM to CM 44 44 4 3a M Q Qu tn o 43 oo Uq4 a i ii O a-. 5 oo 5 tn * a 5jc 2 . . 5I 4* p nt 20 2CM *V_ ua o '49 ea to 4 to o CM M VP VO 44 4 o n <-a to o o O a. om - - --* t: Cl .a +> a 3 <o *-< o o SlV CM Cvl 14 in4 IM <Ho to co ua to to to 4 4 oo O Cs4 .ftft* a . ... CM tO B CM 0 lO 4 N M ft HHH 4 <M a ... OBH N W0 444 CM..M. CM m .. O _. -- .-- CSJ _ _ rH U1 W.N *- nn M' WVo-* c-o 14 rt oo U9 CB CoM CaM <Q H a <D <0 > H CVI g 4> H>acii CM CL 3--or*4i Xa C CM cvi CM to O `A <r> O4 H tn p CM 4 CM 4 to 4 M4 o4*C4* O c0 G ^4 in tn o o o U3 tf IQ 4 . . . .. . _ --. . _m M .. r.<SS N CM rO* efto. oo 030#;<O0B4 * CM ` oa u 3 2BB x\ Cl a vp . O < 33 4> n CO 0D C *iv f A p> M )L 3 N< " V 4O-4 "O o oo o HQ CM 0. VO 44 CM H H O O tHO HIO h rt 4* 4 o C c(C4c3 sc* 4-1 #* "* * C* f 3 CO 4> ic: to to o ftA. c O o M* w* tn ... - .........- ........ -- ... co cvi m O 4 o4 ooO to c* 4 <l>4 (.4 H CM H 41 ... ...-ft. M -------- ------- ___ ^SIS . H AOU) M* tOo4 CM* CO oo 5 CC to < * *4* 90 un. u 8 rO Ul Cl o -5 : bo SO O \A. o d r -4 O U> V M* tn to to o o4 o4 OO O sss 444 HHH i a* s 8. 4 vP ^ CM CVI CM 4 oo t*o ea** to to CM u 1 w Ul Ul o x: to .*>1 tn t: o cvi CM O A. "* -J* 4 to VP vp mm O o4 o4 o4 ooO to cu co CM 4 h4 y 4 H H *M . i N ^o N (U * CM M o o 32 N OB 4 CM 5 M e. a ns X in o i ^ H -* o C) 4 43 n o 44 o O ft-* ui HH0 4*4 3 ft* V o o O H (VI O o t/V VI 82 nnn ??N<n ooo N n ci cm co icj Nrtw HHH i 4 CM 4O uo *tD4. 3 fot. ' i. 3 **' "` ` " ** rfft" N ^ft ***... ** t3 t* 4-t * 4tt >: u 3j; o.J ft. 3 *1o & 3ia ( f-4 5n '30 Huo nu H fl V/ ft aa K #4 . V4 4. o u b 3 "u +> '* o o o 3 H *X3 e Nm O ft V) 09 Ci CMJT O tl *H W V. HO 4 n H 41 o cc -i t: o 3 H o *** O 4 frfe au j % ft O \**wVt I. e* M frfc ft! Q. ui 9 oo sS CO Cl 0 H 23 10 Ci * H5S 1 0o*4 4* X0 X --**' * 4. a4a CB vo -ft 5w 3o It ** oc - 3ft JS C p o ft p <4 . 2 aHO*. " P. K ^c4 I, Vi ?ko 3c: w u ft.*! J? <n U e u wad g-mS foc +* O rt H ^ u P fl`o P. S r. ^ 5 fr-^ T T c table h ^ CQUVAUIZOll OP KKACTION TO CHIiTSOTtLE MV SEKPENTINE I.. .1 ..;' D IH lie AIT. AClfEALLT & Each anlnal. waa injeotod intratracheally with 0.6 cc of a fi par cent euopoaslan of the dust. Two-seeks later another similar injection was given. Total onouat of dunt injected 60 ia. ** Anlnola Uoed Sixgroups of 0 guinea pigs each (eno group for oach typo of dust). Sacrificing Periods la si Quo.or two animala In each group at 1, 2, 6, 8-1/2 and 12 montha after/loJoettou. Preparation of Dust Chryeotllo Cbell-uilled) unhoatodi . Chryaotilo (ball-nlllod) ignited t Chrynotilo (fibrous) unlieated Chryaotilo (fibrous) ipiitod t t Serpentine (ball-milled) unheatodi Serpentine (ball-milled) ignited i Ball-milled for 117S hour*, dried and reground In agate sorter. Ball-ml Hod ohryeotlle hoatod for 2 hours at about 700*C., then ground in agate mortar 2 or 3 minute*. . Ground in agate mortar to pae 20^mesh, 200-bioah oatorial heated for 2 how* at about 700*C. Ho further grinding. Ball-milled for 1400 hour*, dried and reground In agate mortar. . Ball-milled serpentine heated for 2 hours at about 700*0., then ground in agate mortar 2 or 3 minutes. ' v- L'inc rsi Site of Duet Particles Pesult s * Chryaotilo 3 micron* and (ball-milled) lesa unheeted . Grinding destroyed oapaolty to cause fibrosis. At 1 month/ conoidereble inflammatory edoma and cellular proliferation and localization of dust particles about bronchioleaj at 2 months, only a Tory alight proliferative reactions at 6, 8-l/2 and 12 montho, widoly-ocattered anall mononuclear phagooytes. At 12 months, a few microscopic patohes of thin alveolar vail thickening with some adenomatoid change in portion of air spaces abutting on thickened bronchi, ho aoboatooia bodleo seen. I Chryootlle 13 mloron* end (ball-raillod)! lean ignited Chryaotlle ( fibrous) uahoatad 120-60 nicrona approx. . .* * <* . , . . Roaotioo limited to largo forolgn-body giant oolla without production of fibrous tissue. 48- A distinct flbrosio. Reaction loo el iced to connective tis sue about terminal bronohioloas little within thoso tubas. Contraction otmaod adenomatoid appearanoe of air apaae* given off directly from terminal bronchioles. BimUm arei baoarao mailer with progress of tlms) no now region* la- volvud. Mo oliranlo pleurisy even at points abutting:intrm- pula-jnarychai.ge. At 1 month considerable lnfianaucory edess and foci'of cellular proliferation| at 2 months well-marked cellular proliferation end fibroaia occurring f00ally about respiratory branohloioe. Thla reaetion developed be fore at* % . -1 - - < - v -** - v.4 -nA -- m advanced as tha^^rlsrS- "sapou mqauojq paf'Ja oq 05. qonp joj Xouop : . sox `ouixuoJjoo po^iu2i \^xa `ou^quotUoa poqioqan ioj j .. ix '.< -CK po^-juSi } ------------------- :--- ; \____ L|<33 Xivi-jvxocao uov^ooji 'oa/(Vut qona | pn* ouoaopa s' ourqao<u \ '* ' ( poaqu jo uoi^aoWr* qnoqqTA * j .. axaioad oxqqxx Xiuo *e;^uoa 21 foi^iawroetui ojaojqo j j j 'oqquca 2/1-3 *0 ruoixoa^njui 1(00 pioq<5jaX^/TqTB0od ' j poqooqim oQuuqo ou 'uq^uosi 0 luo'R.BUOJuaxd qnoqxx* &mox*o j id oida-tu `ai^uca z P* I IV oai^ouui XxaJ-Xin^V^OQa j X-. j <>x S (PXXT-TXH) puv suaxopz 5! eatqaodaes . ;>H03ta ^uo3iji.t/5/lB a:mpOJd 0^ X^]'JO<IvO \L poXoJ^oap l, ;*jq woqq <*pw* HPl'P* **JoqiJ H* Su^ojj ''v. *xoJuddtt <(X(* oxioo v**l3 poq-u3'v<Kiaj oSaoi oq poqpxjx aoxqooog ^uoiOYO.`03-02 "V".1'&. P*TH*T (anoaqij) OXiqofljCno y' "ojaqacato >00 iisoaqxj II* acio<Ain mm jo soqoqad ooojJT? *P*T 'X *q3 jo "-K>o-inoojd oq 0^ psuiooo oaoqx *ns*xq inu^XJ tJT-oaJMOjyuojq. 2a;oq sea qojqtt jo oaoa `ao-jqajqnjut on . >0 i{)v x;;ueMioii jo oqoq.od O3o XnojoqdlJod BiOJ N.qsfp iqJopiiuoo poonpojd poq Biaojqu jo aaoai p^ovra .spa xm3iiojcq-04^.ui puu -ijod podox*-#p-Xt* H* * HIuoru Jt Vt ocoaoq (>cq aafpoq sxaoqooqaY *XTHouo-lH poqoJtoqTXH0 * HT ooninouoy Joqoajroqa u( <^UT q puo oouop oqinb au oncaiq 4030 cqq wq* *00X0(1(0 .4,q xouimtx xxwa* oqx jo Xqtuto-pa. oqaipceaii q* 03 pOJJ - ` >3itT T7vs* iavoooj *owjo*. ?/x-g ,3V *qup ^Vr ^ "' ^c\fo nisr',3'. * r*H *.* mB T T \. . 'cGUTARiaW OF REACTION Sosago Tra injections Totol doae . 1 * ***%.. , , * '.nlmala' Used . . Pros 6 to 9 v'isriflolnft Periods \ ift#t Usually at 1, 4, 0 nnd 12 months after/ injection ` * >*. ** / jIio of Duet Partioloa Separated eo that moot fibers ard fro20 t Vljacral - "hryfotile . , 'i;- A 'dletlnot fibrosis.! * Additional -Information given'oppoaitae' (Thotford)'- ; (flbrcus) unheatod,Intabla 14 ` : ' r*\ < .hrysotilo * (Arizona| lew' Iroa oontentj 0,2^ FajOjJ .i'. ; :l I 71. /'v'T- . Reaction virtuallyldcutioal/withthc.t.to Thatford ohrysotiio. ;; Barth fi- ? V brosia and aabostoalo bodiosprodaoed with'en aaboetosQontaiixiag very llttlo iron; fibresio occurred; as plugs within terminal .bronchiolea and ' ' aa finer deposits at' periphery4-.v flbroaliT developed,before asboatosia be-,'1 dice moro aeon and- was La. oollularP otato"null-foraed 'at ono. Booth.- With ' . V, ogo, fibroue tissue contracted andoocupiod.'caaller'. area but wuc'mereV- -.-i ;*% dense. Adenomatoid ohangoa similar to .those-with.Thetford ohryeotlle. Pleurisy llnitod to inaaediato wioinlty of early reaction about areas of naaeiro locsaollilzzaation. Asbsstosla bodloo farmed but. wore foawW'sjdAn number. , At V month oftor injection,.,ainuto.fool of mononuolear proliforation a- . bout bronchiloiolloes and is areas.of atoleotaslsi at 1-1/3 manthfl,-',heavy..;V* A poribroDchiolor pateho a 'ofifibrooia oftan with papillary, projections par-.r<N-i tlally cloning . lunen of bronohioloj:' adoiostatold appoarenco markcdi.oon-: nactive tioeuoreaotion choued heavy o ollagsa but no. hyaliniaaticaj :'at 2 months, minute feel of.woll-ctaturad fibre sia.about.broaoMolosj^nt,0 months,'^, mature saboatoale. fibrosis ith:'evidsaoo'of contractioni. ooneidarabla ohra-^ nio pnounenitia tdth infilixatlon of lyrphocytaa tnd;.6sinophiloa."VAt 9 :V aontha, oaali intro.brohoM.olar fibrous plugs with fooT,vof ooro.dslioato ; fibrosis at parlpbory^ >.&/> VJ''*-.'-'i ' \* .nooito >.: rcidolito \ Soliyia) } 'A** *a. *. Typical flbroua.ondo- and porlbroaohiolltia with' fornatica of otyploal-.'. oabostosls bodloo.'.'. Han stratian of bodlsa bogan boforo 4 th month after injection, voll^dovolopad by 6th month. - 'Bodlaa poroiat after. 12th months' . Roaetion a.t*l taonth'. hoovy "endo- and.pprlbronohiolitla;,alraady 'showing f1 ,' brous ohongos} fttolootosls aad flbroelo ifitb soss nooroals at sltd offass< elvc loasllzatlon oC dut.; A At * monthsj i heavy, wldaly-acatt^od endo--*; 'and porlbroaohiolltia, now fibrous, with carkod'doforoity. olV^ronohielaa .' 'and with an adenomatoid apparanoo.;v At 8 and.10-1/2 nonths,-.raaotion in. ; ** .lung essentially the'boss as at 4 nanths.* At-12'aontha ^fooiofflbrouo. ondo- and peribronohiolltls. still.large with more denao soar; tissue wd nsra doformlty of bronchialTtubas but no extension, into,: or. atolectasls of, peripheral parenchyma., . ' ". ' '' . '; '/ !* - T;./ -ft * 4 ,4. V Advanced fibrous endo- end' peribronchiolitis, -. Beaded ssbestosis bodies ; *noted at 6 menthe. At 1 month, aarly. fibrous endo- 'and perlbronahlolltlat^ many giant calls end scism plynpliooytio .reaction. At.l aemthfy. small areas of .ondobrooehlolltls scattered throughout .tho.'ling| cellular 'fibreals..^^/ At 9 and V7 -- --------- --- ` * - *4 ' '* and t .0.1 V* ' " ^ told sppearaiwi . ' r*Ctl C* ^ iy=phocytla infiltration. ' *; 8teMlpr-fr ite* Typical advanced fibrous wdo- and peribrouohlolitle produced by G.S,< suspension (1 cc total dote)) noat .anInala would sot tolerate usual 5 % suspension. Fibres!o wol1-0evelopad before asbestosis bodios.seca. At 4 months, well-developed fibrous bronchiolitis with lypphooytss and gloat oells and adenomatoid change,. At 8 sonths, typical bronahlolltlo aot.. quito ae extensive or as heavily fibrous as with a b% suspension,- other wise the sane. 1'ooy dooply-stained. fibers with a good proportion of hau- rtruted asbcatoela bodies. At 12 tssnths,' heavy fibrous bronchiolitis, more perl- then endobroaohlolitlo,'with lymphocytes and giant celloj Tory narked adsoemtoid oppearanoo. 'LyBphooytlo.lnflltratlas/aad'jglaat.'qelle.but no fibrosis, : A.Tory few a-' vtyplecl asbestosls .bpdlos.^r/At I'mcnth/ many scattered foal of intrubrou- .'W ^iolar-dust wlttiout &a sslraVlccal1satlani lysphooytio Infiltration of ?* 'c:; ' '? > .'triiis and'a few'giant cells. i^JLtQ^crnd 12 month s little ovldnee of dust) .v- Xijr. " -a l^sbroaoMolas cnd-bronehl^uith .gloat oolle la adjacent olvsoLi and-i'' \'wlti.;iiy5jphoeytio laf11 tyatioa^bf.;walls,r .* -v W; *.:t 7 I*. JV, .Ifibroelsjubout broaohlolca,'VAt;l.*sionth#. areas of dust localisation with '."collcpsa o^qlrooll ond.ilnflltratlon wlth acute lnflsanatory'eellst macro . phage*, end'glint o&lls.^TTithln 'the aroa wore a few fool of.fibrous tia- j suo - and.'nuaoroua, orens. jjf'hypertrophy of alveolar:opithal&s&,.: Many bron- r- 'v-Vl.. ;chiolos packod,ylth1'fibera,v.iAt 4 nonthe, general appearance of lesion un ' changedjj'pleura^sllVbtly thtokened over heavy localisations of duet', in , ocoaclonalVdOCsaaisdifeaboatoola body sees. At 8 months, many fool of fl- . bsrs'la.broudhloloa anA^qlvoolar. duets with oellular reaotiou as beforej . ;m-\ ''elso;'leosio!ifoci'c'chswed''dxdtlaot'OollagB deposition. At 12 and 18'swaths, rsaotion^as before ?dth :flbrosis about broaohiolse oon apparent because of.coatrastlou and daoreasd 'o^lnfiassatlou. Giant oslls prominent. * , Ploura aarkedly lnvblvod, -. '. "i ' Bruoits r' le.r >* v-; Vjii ' *.. .* v ..... -v Typical fibrous ondo- and porlbrondhlolitls like reactionSfba eabsstoa niaorals. At l nonth, oxtcnslvo endo-fcoad perlbronohlolitis with giant oalls) tlanoe fibrous loops urlthln broadhioles and oellular fibrosis about thaaj adonosatold chango present. At 2 cantha, heavy lntrabrocohlolor and porlbrcoohlolar fibrosis producing narked deforalty with distortion of tuboa and obliteration of surrounding airspaces) fibrosis pale without hyalinlzatlon but with fear nuoleij no neorosis, T^npical asbuetoais bodies aeon. At 4 end 8 months, little changoi fibrous tissue contrasting. At 10-1/2 months, (Jenso fibrous bronchiolitis with aebastosis bodies. .'Ko piouricy. JJo oxtonsion to surrounding lung. v Glaoa'.tfool ' Vv.-.c.'>:?c ?* .V* ,*** t * N * ... So flbroals within a year. At 1 month, no reaction Inside bronchioloci la periphoral air spaoes cluups of giant colls packed with flno splculoe of glass with lynphooytic Infiltration of sdjAoont wells; no aabostosls bodlos. At 2 months, roqotlan lees intones than at 1 month; fair-sized olitrpe of olongatod giant phagocytes containing aplculos and particles of glnssi no endobronchltls. At 4 end 8 months, ronotion still dlnlnlehlog. At 12 months, focal arose of pnoumonltls with no fibrosis & endobroc- . ! chitioj modorats number of smooth lron-t.taolng flboro. 7 1____________________________ - .. * .. .. . . !\ - hi * 1 V' t* r i 1 " . . TJUJI.S 18 i"i#I^S>iMsbir/o? heactioh produced nr lono-fiber and short-fiber curts i - ' IHJECTEO XHTRATRACHKALLY 'dPooasamt^oo ?$*:>. : &. - v . , .v-nj.>.Sca - injections' of 0.5 co of a_ 5 por coat auapercaioa gLven two weeks apart. AotraljrU*^?-: -VV*.'* = ..' ; . - fix JEToups /o^' gulnoa pigs. : . .' - " ' v- .v ' ' -.' . gaortflolnxPsrlods *' ' i ''.'*" '... .: <. V..A>: 2,:.6, 8/an,d .12 month* after injection. . T{ ; ' ' '* ' : j` \ V'.'t '*-.i?(';\ -.51m of. , Kinoral*.!'>" Duat'Particle* Result i NV's*1 * . t ; i*. i Looj-fiter .. v. A. dlsttco'6fibrosis.'-: Refer to ahryeotllo'.C fibrous) un- 20-50'microns': Ueatod ln' toble ld. '--i,v- \Chryflotlld-vf; ! 5 .... r v -j --*." .1`.` ' ' ' -, * * - , " . ' ( Hartford) v Short-fiber Ho" fibrosis.;'Refer .to .ohryaotlle (ball-mllind) uaheated t ' . *. ' 3 microns end in. teble>14.v'vih.;'.% . ;-losoir.- * # f j - *<**' v'*, .* r i**t #* ^ -- ' . i .7 *. * * . * . V. :*/* VV'nK*. '. . * Lcng-fiber ' Typloalvondo-- end poribronehiolitie. Refer to table IS. i: *.-v 20-C0 microns . .V fibrous: . Aaoolta'?' * *> . * * * V;# Short-fib or 1. Renotioa liBitod to phagocytosis ith lyephooytie lnflltr... .*`STtv.- v .. * * v 20 miorons end' tlon of .adjacent'traile.v Short fibors packed inside mroll.: ' .leoe ' phagocytes longer anaa' free, saaa coatod to fora Vpiosl asbostosls bodies. V At 1 month after inJootion, alveoli c... : * * . ... tainod'good-sisod giant oolls j moot phngooytos traro withi J .* n`4'* ' i . * ' air spaobs'and-had-not'cl grated to valid. At 4 nonths, f. oxtraoollulor.fibors had worked theaealvoa into intorati- tial tissue' vhoro thsro was oxtonslvo proliforaticci of ' * :. - v h* ` . lymphoid .cilia and aonocytoe but no flbrooio. At Q mentis foroignbody/roaotipn with soao pnoumonitis, no branchio- litis.. ;,Typical jasbostoxis bodies prosont. .. Croeidolito ; Long-fiber '- Advanacd fibrous ondo- and peribronchiolitis. Rofor to ' (Bolivia) 20-50 miorona tablo 15.:;, J.' J ' * .. ;l --r . * * ... Short-fibor ` * Ho' fibroais. At 1. month, air epacos ootnpreosod and large, 20 nitron* sod fillod with giant cello paolcod with dust nosdlus. T^olLj ;; , tV *v*s ^; ; . ' ' .* . ' t.'; v'. **I .4 , less heavily infiltratod with aonooytos and lymphoid colls. A. 4 months,.'* moderate.degree of cellular infiltration of wplla) saall giantoolls paakod with dust apiculos. At C andO-l/2 moatha, oaosoa of giant oolle, containing miner' partioles/. In moll bronchi but not in roaplratory bronch: anallor ones widely scattered in terminal air npneos. Euv oroua aebestoals bodies. 17o roaotlon in eonneotlre tLso:;.: Ro endobrpnehial proliferation. At 12 months, many sost- torod small manoeytes p^rhod with dust. Ro endobronchLtlz Ko peripheral flbrosl*:. Vn lymuh node, a slight rotlculv. no fibroslr. Long-fiber Lymphooytlo lnfiltratloe ar.', i,liuv cells but no definite j 20-CO mlc^8 libroeie.'/Bofer to table . ..a * s I ton*, lb"** ! LymphcoycI infllireil--i a"G csa ! flbroiU. nf.r to Ubla 16. CellRbbut no definite . Short-fiber "3Ti:lotCm and ("loss Vo fibre io aiid prsotioally no asbestoala bodies. At 1 rednth," focal oollootldno of duot-filled monocytes and a giant o.\lsi et 4 months, om adonomatoid opithellal re aotionf nt 0 months, ilraplo pneumonitis with phsgoaytaaii of ohort-flbcrsi at 12 months, isolated end sharply local ] ited oollootions of dust eellt ineide oi$ spaoos about ti i minal arterioloa. Reaction in walls Halted to lymphoid I osll infiltration. No fibrosis. In lymph uqde, reaction { llsiitod to slight proretnonoo of retioulua. ' Long-flbor : 20-50, microse Fibrosis about bronchioles. Refer to table IS. __ -fibor ` 20 'aiorons and Uu Slaplo foreign-body reaction. No eoute inflammation. Ho accumulation ofiduetinor about torainal branebiolas. N oadobrooohitio. At 1 mouth, scattered small giant cells and.eohbidoroble:infiltration of ftdjacantrmaal-l-^ien't^oei an4-nhadjacent vall^ with mono I cjrtsa'i'nnd lymphoid cells. At 4 months, littla change ex- ' v-cept mere oollulwr infiltration of connective tisane* At hpaths^lycphoid''infiltration and thickoging of walla -sho aora^but not> all terminal br*ehiole a. ' Long-fibor '' : 20-50 aiarons ; Short-fibor , (aado by __ crushing long f 1- ' ,,bers with ;rubber po' llocmea) *< TynlcaT\flbr-Qua ondo- end poribraaohlolitla like rsaotian to asbestos vainorals. Refer to table 15. \ ' ' Inert typo of reaction. At 1 couth after injection, seal conecytos vidoly^scattered through air spaces) focua of atclootasis with lymphoid infiltration ol&corepressed air space vails. No endobronchial reaction a,a with chrysotil* j/.t 2 months, reaction'-slmllar to that st 1 month) typical jaabeotosis bodlos noon.\ At 12 months, email clumps of In- iaotive duat-fillod phagocytes) no fibrosis. No reaction (ixa lymph nodes. ' . T ; :i ',i . '.i .. c : iraA7t;:iors technique ** ' . .* . t ! * ' . '.J ~ ................................ o? l'per dent ' suspension) v&lch wero givon ttrlcs a ooek.'for 10 woflk*.' -"1' ' : -; - ' 'i'I*, , .. . ; 11 jv.', v* ** *. " . * .*' ?* ; i **. ' /; , . .4 / : . > V:5-v^%-\ f .r '"" . ' 1 ` i .*w?v -,v ' : ' v~*&<?-. *.. -'t-% % . killod3 animals at9, II ud 17 smtha:raftOT-'last;.lnjeQtica9;ShortcaliBg intended ; tplloatlng picturo. Hcrr-avor,' rabbits saord^loed doirllor. (8;*and_6 months).. shored : *10 prcgroanioa In tho 0 months* animate ;l Tha-las^-traoIXllr,en d 17.wocth<) woro probably la of. tho liTtr and amyloid of tho splecnmd* ln^orprstetica'difflcult. :* .. :' ' /. ` Aiffl v ' ^ ` '' y: >" v/s*!.!*' "..A"v ' s * * - ^ '.-.ttanco with no'chcngo in 12 nontha,-;. (Other;oosorvuticns.-atJS,{.dand-6 months*) I-. l-;!Io tondonoy-to agglomerate aid nooheago .la^hdjaoexft'.tlssnao^lhrlndlswthm ur.ciar destroynd' tho fibrous structure of this ninernl'iajia;inJootod'!Batrici2^To- - '' Vwt*. : . ' v ;V .. " ~ ' 7V.;rs -V ".. - '*'/ n Ltnrt mineral. Observations mado at 3f .S, 12.and.24 csontha;;- Only saggoation-of.;. ted In spleaa and lymph nodes,-but sot tho liTor/ of thaV24-nonth:rabblt. ml- 'ou of cononuoloar end giant oolls that traa cot;proaimt'in dithor *plo<n:or..lynpli sodo ;oo ct aaeoclntod fibrobluetlo'roaetlan In the so ..'organs tndJ;of: any ahansein.tho liver. >'' `.fii^ntion of ont!iopbylllte as cn inort ailioato,^No fibers, woro. retained In [lung to- - ' ' .a bcdlo voull develop. .^ ' \\ .. ' - . . *. . : '". . '/ ' Tms Inert tuir.crsl. Last animal'sacrificed showed d'littlo'proliferation- and lymphocytio *: * etrllcr (at 3, 6 end 12 months), ' No.evidence .of .'any sotivlty in'lesions .In othor . " _____ _________________ _________________________ . ' ! . './*'.> a'.` f.r t r ?"{.{ ' "............-..i ..;h :%.<! 1 . . ; - ` . '?<!'*,..'`i*...' . '' A .' . * , :; * alth no chnngo la 2-1 month*-., ; Obeermtlons made. at' 12''and-2'i'oontli._. . ,:. : . ' ... -J.l . . -.v; S'/V-'i' ** * i> ' \i" '-- ' ' s#` *rt , . * . -V . : . >. .. . . hrWVY *: * *' ' A !*, * "' 1" n . 1-- ; - . .... . .* \ *. , .-`.v. ,,?-'- >/ " >. s*..* ? '' ^ ;--:r '' v*.-..V . /v * ;s>: ........ . 1 - ?*' - v * }* * y*;* . 1M,l ^. . * ?rv: T T I,J . ' / i A . ' . J J l . . 1 t K --K l*i> BTCTtr '* . ** ,.**a-. *. .* . 4,, > 'k'i ^ r **; i . t. i '* . y.\ .... VV .V v * '*> i ; *. 'v.' *5.'t .-. ,:;:-'vv. .; ' . \f,;. -i:*-- > s * V :*.</:-* f..-V % , . ;; -tmiu. % -i . .-5' ' 'v. * . 'n'=v; .V^fcKSV- T-V v\-. . . ; V: v>c; . .'`JSSaa'*M-- -J.' vtZ -- m t. !i. . -.-* .. . ' *;.*... V ( o . l>*Ui sumiARi or isjECTioH Birr Uaxlon ' .' .Surrival *. f. Ji'Claa Of v: ' Aninala ' . After l^ast ' i'laral ^ - >.Daot Partlolaa. ' Uflod ` ` In.loctlon ,* **'*Xm* ^ * V**W . # * -.If . tTVs' montha . Chryeotila V'.. S nicrons end'laas drobhlta :(Thtford)`: . . ,.V './.I :;:'V.192 houra) . * "/i ;`*' %*, ?- .I f `' _'I ' Kt* 4k* *i* ? * ' S'' ;.V! . ' ' * 'I * V Tha rabbita did not tolorst: injaotlona of eras ill luted i pension (69 dsys aftoir firs' plsea and Itinga. ito thrni disoorarad but matarlrl rry H* * U * , * . f* % ,]*' t v>' "V,:! *$V' 'i ^ r r 0-*'** f* S nlorona cad loss ' B.rabbita ground In - ;' y cartar): : T + ,fk*'.*.; /Vv, :<-r%v.tr**.-;.. < . * \-~K'''***' :V;xj'i *v jr* , .*.*?'. 'i* * "* . . >. - * ' 'Adrenoad p^aonary In fee tin* ' duration of axparimant aid c only lnort phagooytosla vitt tha esaa alth*ough fossl * oeei>` : 4 .* * . . Crooidollta ' S niorona and lo . 4 rabbits ' '^2 4 . *i. ' .. ;,,,s *. . \ . ' *"' " ._**.*,*. . . .* ' *M i . (ground in ; ` - agato sortar) " : ;'/>: : . .-V . '* . ' ' * % \ l> **.. :** .*..m..: * ... * . i *. * . ': ,\< . . * *i* * Reaotlon vas that to on lc<r Sinpla phagocytosis'vof pari' dust to eisos of S.tdorona srahlsd. pluses rather then f ... AnthophyJ.lit \ . 3 cloroao and loos ' . (ball-allied ; p-|.' ldOO hour*) - ! i >. i . 1 ! * ; * j. ' V ' v* ." *i 4 rabbits .*/ V<uC V* .** " ,1-** * \ iv' ; > . ;:-i? %. v 24- ^ i. . V. ; ` ' . . , , . Trenails ' ; (coda-Iron) * ,f *. V.*-r.,.r': ; t; .... ' Sal crons and. loss - 4 rabbita 'l !*. 19 (ball-allied v t " ,V ' " - W '* /. >:' -14Q hours) - *: ti* mt . 1 . * * . ' TM . Trcaollt*; : 3 nloroca and loos 4 rabbita : . >24 ; (sod,a)' ** .(ball-mlllad . . ': : . - . r. . .*?: v-*. .'i :** ' * : - .(rf ;i' 14'd hours), ': * , .j h 1' Roaotion osacatlall/ that of irritating properties Tartlfi isal thoro had-been ') roll for^ of 12-aonth snlasl.| Tha shr condition justlfiss ;*t!ie +1** dcacaatrato xhotherinshvaiee . * * 0 Roaotion oasootlally that-ot' Infiltration.in llror, not t organs. .\V v!. An inert forol p\-bo ly roictl M>-Ji, ip * '^V.'-V.,. 'V.VvVi ' /* * V* . :K- * * V: **v : V '>'*; *- A * 'X- * *'* *'* * Vi? * * ' '; . ` % *S T ?V.'N ,. ,t. .. v . T' ' i . . V f* r*r -V-^ee. T V ziu Armricurm tecihiquu . . . * * *. 't ' .'; *uot.r.ispenelcn. Total anount eC oust Impacted -0.Z e^am.' ;i:.` .yrv.-; *;. j r&! _ -.-.. *~v ' v Result*: ^'r.vKv-V.'?.VA. -s-'^vV.. : ! :V .V *<>?.Vi ' Cf, *** ** * ** "111 T..**' "* " "" .*' ' - i -- .. V _ ' J.... ... . - (v,. y bodloa, . Dust partiolo# ingoated by phagocytes''Tahiafly imltlnueloated variotyV/; SlX'.y 'T.V -'rocs >103501* of dust Bp poor to have, dlesoirsd 1oaring only tho lnaalubl* magntlto>; ft'f;' *..n surrounding fat or areolar tlaoua,..-' Ho. transporting of dust to regional? lymph nods*. * ^-"S ala fraa 1 to 36` xunthtaa aftor j$| : ' ' : ' ' . V ' .O . - .- .'V'.. 'X:-A '.y ' "rcdiieod, delicateo and nan-hyallno. vt-Atypioal a*b**tois "bodls developed but-'all'-wire e of extra-losg fibera com. Obacnrationaonly.atZ nontbs. _ - ,, . , . . . : ' | `` . 1 - * . - *: "'t 4 'ntcrprstatloa. . Dust rotctlan"appoared to bo of .inert typo and limited.to pbagooyto-'-.;-; ; < .cy to lyrsphocytio Infiltration'.- Observations at-1, 4,".8 and 12 acnths.V . V;T 1 ' r ; C't -Uf r <\ A ;-v - " . . . . - jpi largo Bonocuolear and giant phagooytoo-surroisidod by. a adaleaaa aioaunt of bailular . >etod dust eontalnod not only flno naterlal that in'grinding had baoa naahod into * , :.-sy long oplculea 10 nlcrona or norc in; longth. VlTo asbostoals bodies soon although- " od clightly.swollen and grconlah.-' 0biorratloaa'at'l,; 4>v8 and 12 nontha." . -i ________________________ : .v r'nv. *, '' : v. ' w.<-. .-t.- .' >,- - ...* ~- .<-**. 4 K*yt *' **/'/*.-,^ -x\ * * ; ' -*N ... , - * reactloo. Zn/oerly aataals (1, >! aad.8 t^tha};f0oc^'af'auinobyteV sad coal11-giant . oeroaia. In tho -l-nontli animal thoro wao alaa. slight "periphoral'.fibrosia.`'-'fAt'l2'f and .- r-aco of nonooytoe and giant oalla; no flbTOiia. ^'X,.- ;.;.:'r.'V.vr. - Va* . J * .' *!. ;* ,t ^ * %* * f vary largo giant oolla surrounded by`a riu-lablor ruB4wr-|'of lymphocyte*^,-wts'BaeU.. .t-U.y long fibora than to tho fine duet: ip tho osporinont' aboTO. ; There nas jeoro'or : ihltsta producing cellular connective tiasuo .sioiblo. in' brans whore; the,1 quantity;of-. - * ? groat that it obocruod tho reaction.. Obaervatlono at .11..4, 0 and 12 Booth s.'.vV : 'V* r;:. 'V;vvtf' i'-ii \ ^ Tl'> r progroaaing bayand tho stage of Tory s.UligJhL at. ely__c__p_ho c-ytiolr__e__a__oUtio._a_ _aboirfc .piosoB.*joaJfI .. `} f ^ llbroala. Obaerratisnu at 1, 4,'8 and 12 i ` > '' * - r. '< V -W- t t t ' .. i-' ' `' n-lody typa of roaotlon. Ho fibrosis. O. bs. ervations.1 *at'.1..'-''4W. 8*, rrd .1..2 and 10 .ae' n. tha. ' ' . - r*~~~ 1 T ,:-7 " . j -7v...' JV; *. '* r f.J.. ?oed by anthcphylllta ami fibrous pyrophyllito vith subaoquent .rogresslcnj ^rstal- *<. T(^outl At 1 uenth, gloat cells about long thlckr'splintoral at 4 months, deflnito . l.'i of anthophylllto and fibrous pyrophyllito reaction} at 8 sen the,-fibrosis trhloli sr.sod, especially with fibrous pyTophyllifcs.'.VAt;12' uontha, raaotlon to. all-three^ **- ocy giant colls with lyispbooytos but without necrosis or fibrosis. ^ Vo .asbeatoals * -, -?t tuapenaion. ' ,j * rVv-? : ; ' .' . . ':'VV : ` V<-- . * 4t , -r v'..... ' i'-'.v I ' * ' C v `. TJinut 18 V ''''`t'Cr- . " . v_ .1 ; j...". swciart op iwectioh expoi UE*TS ST 1 ; JotKt^'Ewjb.nlal*;roc*lT8<i single injection Intreperitoneally or Z go of a SO pr w s.' . `"t - r TV.......j . at . j^%inoralS;:-: '/Ssii*'*:?* yr *.:'An ir:l Uaxloua Burvi-ral After Dual Partlolea ' *' Used Znjeotlon - w* . Booths ..C Chrycotile ..jUj;7 * 3, ialorana .and loaa. V/ 38 No flbrosia nor ^obostoai 'Vis ( Hitfe1 r_J d<#)m''"<34.';^. ball-alllod} ... TrVZld; hour*) . ,*: i v ' ..%4 S *. ,m.U** .*''irs -<yr.;>.:V.V;S .* * *: . ; fry,, if oontho oftoy'lnj ootloa f? oasitaBlsant, Vo.roaotloo Obcorvatlcn* sadl t intsr .4 . . , %** Chrysotilo ,>`i (Ihetford).-; Long-fibor .`'(through 100 Bach) > *.*/* * -. . 44 2 \ ; v-"* * * i ** Doftnlto flbroua roaotlou unusually call.! So vrtdc *. -v r.VAnoaito * V'.T-rr.. V*/ .J>v t : . ^ .^ i | V ,* * *. fi J' *. v^.v" ' : *: 3^nlorosa and lees*. ( (grouad la agtito ; f--oartar) `f ` :Vc-. te s r?I'#'12 ' r. \ I Infection lntorf^ud ultl sis vith.a'nodorlata toad* V? >.'* 'vJtv. ' 1 Crocldolito. * *:;r ; .* . :C*V i 3 nlorens.aad loss) also loo long ...: enloulaa . ' (ground In agat* ' . cartar) .: 'v:-.'.- v ; ^ v.:` s* *T* # .VJ.1X . Dust .fodjr.oonainVod only oonnoatiVv tlasulo* The Irregalsr' plotos bat also tho longer apicu'lea appr iathophylllto 3 ntcrons and lens ' (bal1-wlllod^ ' . ' K00 hours).., ' .5 g* pigs 26 Esccaatlally inert foreigr soils and a littlo eentrs 26 ncath|/. noa-pljrogrsssi ' 'Anchophyllito- Uoatly 3,.aiorone and V ' (originally ; loot} ooao flborn 30 labolod talo) aiorona ornoro long H ' . (ground In.agateV : * cartor) ' *%*r. -----* ---.---.- :--- :--".r. * .* -Tronollto"' s-} 5.nlorons end loos ( soda-iron).. ", (ball-allied^ \ f-. 16 hours) ` ' ' I Treraollto . : (aodLa) 3 aiorona and loos '-' (ball-milled)' * 40 hours) ' Anthophylllto | 100 olcrons and less Og. pic 12 .6 g.-pigo - 12 :'.S 6 g. pigS 18 -----------------------j-----------6 g. pigo | 12 Pyroohyllito (fibrous) 100 aiorons end less ..* . pic* I 12 Prrophyllite [j ICO nlcraas and less < .6 S. pl. ; (crystalline) J 12 Reaction, vhlah . con si etc hoavior to the ee. un intent lees proliferatl os of fI forolgn partiols e no ' ' 1 i .1 ' Inert type of response ns duot-fillod phaK3oytee I' I Inert non-pro pros tiro rot i Diotlno^;'early flbroots i _* lino pyfopUylltt^ Inert * i fibrosis replacing giant started at 4 nontths tad < ducts oonaisted af forsli [ bodioe. . .< \ (1 i '.i Each soisal receiving long-flbet*. enryeotila vita InJo oted with 2 co of c O.G' `jer cen* '. ;V*; . T T cc TABLE 19 AUALYSZS 0? FXBR003 UIKERALS % li i Asioalto | Araphlbole per oent per oent Anthophylllto per oent Sruolte ichryaotilo Croatdolite Tromollta per oent per oeat per oentj per cent S102 40.23 55.04 59.80 0.90 38.56 04,99 66.20 F23 FeO ai2o5. 4.00 33.83 1.09 3.00 1.69 0.57 0.32 6.70 9.36 0.40 2.35 0.34 10.27 4.29 iji 7.21 0.66 cb 2.01 12.22 0.44 0.04 0.03 0.80 4.44 UgO 6.28 23.29 .33.37 63.09 38.96 12.25 20.62 *+29 Kz0 0,33 0.20 0.45 0.12 0.52 0.15 0.91 0.16 0.20 0.00 6.92 0.57 6.78 0.99 Ignition (<1Q5*C. Loco (>105*C. 0.68 5.20 0.32 3.GO .0.27 4.08 0.53 26.66 4.30 14.99 0.62 2.06 0.34 2.73 59.97 I 99.77 ij--- - 99.52 99.79 99.69 99.68 1 99.82 \ / { Kl 1 '1 < * rA Fig. X - Uuman asbcstocls (P-56-144), The photo micrograph rovealo a bronohiolo (rigjt center) with a cmooth nusole bundle at lta inferior margin end with an extensive tone of oollagen deposition largely obliterating the carrounding alveolar structure, Tho black foci aro macrophages containing in- eidontal pigment. Aabostoals bodios ore present but aro not apparent at this magnification. (200 X) \ \i \) 0 r T c* * Fig. 2 - Human asbeatoeia bodioa, Thlo oolloo- tlon of asboatosis bodioa wan found in the lung shown in fig, 1, The usual variations in site and configuration are rcprosontod. (400 X) \ T ( iM i) uJ c.c * I 2 - Guinea pig aaboatoala body, This body la similar to como of thoao ohown in . fl*. 2 ( 400 X) y/ / 7----------------------- T cc &w' I Ftp;. 4 - King's floats Inhalation experiment. Guinoa pig with 12 months' oxpoouro. Tho figure Includes a respiratory bronchlolo( at loft, branching and bo - oomlng on alveolar duct, at right. Koto the accumulation of oolls in tho wnll of tho bronchiole and In adjaoont alveoli, . (130 X) .X 'U M M - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - r- - - - - - - - - - - - - - - - - X rig. 6 - Ring's floats iahclatlon experiment, Gulnoa pig frith 23 months' exposure. . The field inoludoo a bronchiole, at center, with porlbronchial fibrosis extending into the trails of adjaoent alveoli. Koto the ouboidal epitholima lining these alveoli. This la the so-called "adonoaatoid" epposr- ` onoe. (200 X) I ^"7 -v ~z~ T v Fic. 23' - Glass wool lnjoctlon experiment. Guinea pl5 injected lntrctrachoall/j 4 months aftor lnjoctlon. Tiro bronchioles aro aiior.-n, one in cross ooctlon end the other in longitudinal section. Holoir tho latter le a thlck-wnllod blood toesol. Tho brcr.chioloo are without reaotlon end a an bo considered normal for comparison with other figures. Glass wool fibers tro proaont in thla field but cannot be aeen at . this magnification. (200 X) \ . C? \? ^ *& ------------------------------------- 1----------------------------------T-----------------------T o Cuinoa pir iti 7 LM Priw,nt aura andfh!:? 6 nonth#' d"fc pc . Jh<> reaction io r^U^au^5 w* produo., mr^'rr(f tion. (200 X) *tonelvo roa. IT li l I I l j Oi Oi C* T----------------------- ct /* 7 ** King's floats inhalation oxperlmont, Guinea pig with 9 months* duet expo* sure and thou in normal air 37 months. The reaction shown is stars than that lfi fl6 6 but much lose than tho reac tion In fig. B. (200 x) 0 \ C? Q, V*v H------------------ ir C c. * v rig. 0 - King's Hoots Inhalation exporicont. Cuinoa pig infoctod with tuborclo buoilli and thon exposod to dust for 24 montha. A bronchiole ia shown just above contor. It is surrounded by sons colla- 5on dopooiticn together vlth typloal . epithelioid ooll infiltration of tho wall. Roto tho laok of encapsulation and tha peripheral epitholioid ooll pneumonia, nhioh illustrate spreading tuboroulous prooess. (200 X) n nO T ( fc tig. 0 - King's floats inhalation axporinent. ' Guinea pig infootod with tuborolo bacilli and than exposed to duut for . 35 months. Note tho subploural dis- 1 tinotly-oncnpoulatcd oasaous focus, . tho calcification at the right border of the lesion and tho aboanoe of oella in adjacent alveoli, all of which il lustrate a healing tuboroulous process, (200 X) I \ T TT c Ip t Hg, 10.- Ball-allied aobeetoo inhalation oxpori- ncnt. Guinea pig with 24 months' dust sxpocuro. A bronchiole La shar*n at the oonter, with only slight accumulation of phagocytic oolla but without tho for mation of collagen. (200 X) CT+- f= 1--------------------- TT (c 9 le. XI -Ball-rallied asbestos inhalation experi ment. Culnoa pig with 28 months' dust exposuro end then in normal air 12 months. The roaotion is much lllco that show in fig. 10, but there is a slight deposition of collagen, most apparent at the left. (200 X) A. % \ . ccPP T T c * Fig, 12Long-fiber aeboatos inhalation expori mast. Cuinoa pig. with 0 months1 dust expo euro. The bronchiole, at center, alrosdy shows an accumulation of phago- cjrtlo oolle, with slight oollagon depo sition. Compare with fig, 10, showing tho reaction to ball-milled asbestos after 2>1 months, (200 X) * & r~s T cc fc VIg. 13 Long-fibor asbestos Inhalation expori' nor.t. Gulnaa pig with 16 contha' duat oxpoouro. Again noto a branchlalo with its surrounding reaction consisting of fibrosis and adononAtoid ohange. Col* - lagan deposition la now oacn in the walls of adjaaent uItooII, at right. (200 X) r uaHH T----------------------------TT VC Hg. 14 - Long-fiber ocbcetos Inhalation expert ' tnont. Cuiaee pig with 34 months' dust oxpoouro. A bronchiole is at lower can tor j the large aroa above It reprosoats the Involvcnont of alveolar walls. Campore with fig, 13 and note the lnoroaaad extent of roaotlon, (200 X) c K \ T"-T tr ( Mg, 15 - Long-flbor asbestos inhalation oxperl meat. Guinea pig with 20 months' dtst expoauro and then 14 months lax normal air. Tho roactlon is essentially like that shorn In fig. 13> the bronohiolo at right eenter la aurroundod by flbroala with adenomatoid ehange at tho right. There is residual earring in the walla of adjaoont oItoqII at tho laft. It la apparent that no pro gression has ocourred; (200 X) M 1---------T cc IQ - Long-flbor asbestos Inhalation export ' cant. Cut with 42 months' dust exposuro. Too bronchioles aro shown with adjacent cellular reaction and collagen deposition, (200 X) 11 \ ; T ki kK K T cc *tth Coll* CfUlar *nJetloa ,, . t"cu,"- t) 1!>(2oo 10 ^ir:rhtiv i III) T 1'lC* 10 * Dell-ollled asbestos lnjoation export* merit. Gained pig injeoted intratracheallyi 4 oontha afftor Injeotlcn, A bronchiole is ehasn at the right. In contrast with fig, 17, note that only a fon oells have aoousai* lated about the bronchiole end that oollo gon deposition is absent, (ZOO X) / i tnn ------------------------------------------- --- ------------------------r T ion r < *I Fig. 19 - Serpostino injootion experiment. (taiiioa pig injootod Intratraohoailyi 4 months a/tor injootion, A bronahiolo is shown at loft center. The phagocytlo oolla exhibit little pro duction for tha bronohiolo and col lagen deposition is absent. (200 X) / \ r\) rO N ----------------------------------------------------------------- f-----------------------T c 'Ig, 20 - Amoit Injection experiment* Guinea pig injootod Ititrntreeheallyi 4 month* after iujootian. The inflammatory roeotion exhibits pronounood aoeunulation of oella and oollagen deposition* (200 X) \ , noor --------------------------------------------------------------------- 1------------------------------T r'iC., 21 - Crcoidollte injaction experiment* . Guinea pi inJoetod intratracheallyt '1 months after Lajuetioa* As in fig* 20, poribronehiolur accumulation of cello nnd depoaitlnn of oollagcn are sliotm* (200 X) i . >PP^ -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - r- - - - - - - - - - - - - - - T PiC. 22 - Uruolto injection experiment. Guinea pig injected intratraoheollyi 4 sonthe after lnjootion. Even trith this nanel lleeoua fibrous mineral thoro i peri bronchiolar accumulation o.f cell# and depooltlou of collagen slailar to that ohcnm in figs. 20 and 21, (200 X) c\ a o a l- - - - - - - - T