Document 8R6L6qwyykLXoJZ7w3v8b73B

FILE NAME: RT Vanderbilt (RTV) DATE: 1955 DOC#: RTV239 DOCUMENT DESCRIPTION: Saranac Studies of NY State Tremolite Talc, Arch. Indust. Health - An Experimental Study of the Effects of Talc Dust on Animal Tissue E x p e rim e n ta lE E E tu c ly o f th e E je c t o f E J a lc 2 W o n m i n i m a l E Ji u e G. W. H. SCHEPERS, M.D., D.Sc. and T. M. DURKAN, M.E., Saranac Lake, N. Y. Tin- na'iirri'iH't' ni ;i series ni <U-;ith> irnm |iillm<>n:irv disease following exposure tn talc mining ill ll|tjh t New York State caused Idle Saranae I.almratnry to inquire experi mentally into tile precise causative agent nf tliis inrm ni pneumoconiosis. This series of experiments, in which mie ni us ( T. M. D.i |iartici]iale<l. was conducted at The Saranac 1.almratnry under the supervision ni the late l.erny 1'. ianlner. M.D.. (hiring the period l'U7-19-ll. and the results are now rejmrted for the t'irst lime. They have lust neither their relevance nor importance, as instances ni talc pneumoconiosis recur sporadically, and a recently resected lung apical lnhe from a paper-mill worker, suspected to he suffer ing from tuberculosis, revealed on study by one of us ( ( 1. \Y. II. S. ) that talc dust may cause lung disease in the most unexpected of occupations. A study of the dust to which eight fatal cases were exposed and of the minerals re covered from their lungs 1 showed that the mineral talc is hut one of the components of commercial talc, to which tliev were exposed. Along with the talc there occur in variable proportions trenmlite. anthophyllite. quartz, serpentine, and dolomite. The animal ex periments were, therefore, designed to probe the specific effects of each of these compo- Kcrook'd tor publication July 11. 1955. Director (l)r. Sclic|tcrs) and Associate Director (Mr. Durkani. The Saranac Laboratory. (lent substances. In these experiments the mineral, or mixture of minerals, in the form of a dust suspension was introduced into animals by the intravenous and by the intra tracheal technique. Babbits. guinea pigs, and rats were used, but not both teclmi<|ues were employed'for each species. Minerals selected for their purity were used, and in some in stances contaminating substances were re moved, or reduced in amount, hv sedimenta tion in heavy liquids. The progressive and essential steps fol lowed in conducting these experiments are summarized in the accompanying fables. A separate control study with tpiartz was not performed, as the effects of this substance had already been established by previous ex periments at The Saranac Laboratory, and those experiments serve as a control standard. The intravenous method of introducing dust into animals was used in an investigation in which the mineral dust, ground until the particles were and smaller in size, was in jected into the vein of rabbits and of rats (Table 1 t. Both species were used in the studies with tale, soda trenmlite, and serpen tine. and rabbits only in e.x[>eriinent.s with soda-iron trenmlite, anthophyllite. and dolo mite. The intratracheal technique was employed in three sets oi experiments. In one set (Table 2), the four minerals studied were injected in the form of particles 3/c and less in size, and, in addition, two of the minerals (trenmlite and anthophyllite) were used as a dust composed of particles 20p. and smaller in diameter. In the second set (Table 3), which was conducted with fibrous minerals, the material was crushed and then separated 317 A. M. A, ARC!in'ns or IXIH'STRIAL h ea lth T a b l e 1.-- Intravenous Injection Experiments with Talc and Associated Minerals Purtide Dosage; Periois Size: 3 ti un<l less. F o r rabbits the to ta l am ount of dust injected was 1. gm. divided into 20 equal doses (each dose was ml. of a 1% suspension) injected twice a week for 10 weeks into ttie ea r vein. F o r ruts the to tal am ount of dust injected was 100 mg. divided Into 18 loses (beginning a t 0.5 ml. of a (>.25% suspension and increasing to 0.5 ml. of a 1*3 suspension) inject*! twice a week fo r nine weeks into the tail vein. a t Which Animals Were Killed: Usually a t intervals of 3 to tf m onths up to one year a fter injection anl at intervals of i> to 12 m onths thereafter. 1 Mineral Time Bailmilled, Hr. Animals Maximal Survival After L ast Injection, Mo. Results J Talc (Georgia)................ 4 rabbits 24 Bronchitis, hronchiolectasia, endarteritis proliferans macrophage catarrh, pleural thickening Talc (Georgia)................ 7 8 rats 15 Inert 1 Tremolite (soda-iron)... 140 4 rabbits 19 Inert fi Tremolite (so d a)............ 48 4 rabbits 24 inert 1 Tremolite (so d a)............ 310 4 rats 10% Minute cellular infiltrates % Anthophyllite.................. 1,400 4 rabbits 24 Minute cellular infiltrates I Serpentine........................ 4 rabbits 12 Persistent paravascular granulomata 1 S e r p e n tin e ........................ 7 6 rats 12 Persistent paravascular granulom ata i D o lo m ite ........................... 3 rabbits 24 Transient phaitoeytosis and toxemia T a b l e 2.-- Intratracheal Injection Experiments with Talc and Associated Minerals Dust Composed of Small Particles or Short Fibers Dosage: The to ta l am ount of dust injected w as 150 mg. divided into three equal doses (each dose was 0.5 ml. of a 10% suspension) injected a week ap art. Animals Used: Guinea pigs. Periods a t Whieh Animals Were Killed: Usually a t intervals of 3 to 6 m onths up to one year a fte r injection and a t intervals of G to 12 m onths thereafter. Mineral Tale (Georgia) Time Hallmilled, Hr. 650 Tremolite (Alps) 48 Trem olite (Alps Anthophyllite Anthophyllite Serpentine 1,700 1,500 Particle Size, 3 and less 3 ami less 20 und less 3 and less 20 ami less 3 and less Animais 13 Maxima) Survival After L ast Injection, Mo. 28 ri 38 u 12 r> 12 G 12 8 12 Kesults Hronchiolectasia ami bronchitis; perivascular and lierlbronchial cellular proliferation and fibrosis; flbrocellular pleural sclerosis Transient macrophage reaetion and persistent eosinophilia: perivascular and peribronchial lym phocytic infiltration Incipient hronchiolectasia and peribronchial fibro sis; incipient periarteriolar cellular infiltrates Catarrhal bronchitis: peribronchial, periarteriolar ami cellular masses; peribronchial fibrosis HronchiohK*tasia and c a tarrh al bronchiolitis; peri bronchial fibrosis Chronic bronchitis and hronchiolectasia T a b l e 3.--Intratraeheal Injection Experiments with Tale and Associated Minerals Dusts Composed of Long Fibers Dosage: The to ta l am ount of lust injected was 75 mg. of trem olitc and 5n mg. of antbophyilite, divided into equal doses (each lose was o.a ml. of a 5% suspension > injected a week a p a rt. There were three injections of treinolite am! two of unthophyllite. Animals Used: Guinea pigs. Periods at Which Animals Were Killed: F o r trem olite 1. 4. 8, 12, 17, and Is m onths am! for anthophyllite 1, 8, and 12 m onths a fte r last injection. Mineral Filler Length, Maximal Survival After Last Iiijecti>n, Animals Mo. Results Trem olite (Alps) 20-50 0 IS Hronchiolectasia and bronchiectasis with peribronchial pro liferative fibrosis and cicatrization; interstitial fibrosis and macrophage proliferation; tremolite bodies; cellular m etaplasia Anthophyllite 20-50 6 12 Hronchiolectasia ami bronchostenosis; focal peribronchial cellular reaetion; irregular fibrosis An experiment with long-fiber tale was not conducted because attem pts to obtain mineral specimens con taining long fillers of talc were unsuccessful. 318 e e e e c t s ni- i . i i . c t> r s r o x . i x i m a i . r is .\C k T a b u *; 4.-- Intratracheal Injection Experiments Mixtures uf Talc Minerals and Quartz b o sajrv : T h e t o t a l a m o u n t o f d u s t lfijtMti*d w as 7.' m g . iiv!**<i in to th re e ejual d o ses (each lose w as <.;> ml. o f a .V; suspension i n a week a p a r t . A nim als ( seti: (uiueu pigs. P e rio d s a t W hieh A itim als Wen* Killed: I'sn a lly 1, 4. S. an d 12 m o n th s a f t e r la st in jev tio u . M ineral M ix tu re T u l i .................................... Q u a r t z ............................ Per <V M T r e m o l i t i .................... fi.* Q u a r t z ............................. 3 . A n th o p h v llile .... Q u a r t z ............................. t: T r e m o l i t i ................... 30 A n th o p h y llih * ... _o T a l e .................................... ;.o T r e m o l i t i * .................... ji A n lh o p h y llitv .... : T a l e .................................... 13 Q u a r t z ............................ u Partivi Siz, ji 3 a n d le ss 3 a m i le ss 3 S itu i le s s 3 a m i lss 3 m i le ss 3 a tu l ju-.*<o 3 am i 3 ani Ics* le ss le ss Ani* m a is t> M axim al S u rv iv al A fter L ast Injevtiou, M o. 12 6 12 l> 12 12 12 K isults M ultiple flh rneellular.yniiiuloiiiatu; brotiehiolitls arid bronehioleetasia; perivascular flbroeellulur reac tion ; periadenitis mi lym phoid hyperplasia M ussed lu itcro p h a tp 's a n d soin c e n tr a l n ec ro sis a n d peripheral m inor fibrosis; transient bronchitis MassI co n tin en t su b p le u ru l. a lv e o la r m u ra l am i perivascular cellular proliferation; m inim al fibro sis; bronehioleetasia and bronchitis S u b p le u ra l, p e rib ro n c h io la r, am i p e r iv a s c u la r inae* rophage umi fibrocytic proliferation Massive exuberant nm erophaue and fibrocyte cellu lar proliferation; bronehioleetasia am i bronchitis; m inim al fibrosis l>y sedimentation in alcohol to isolate fibers approximately 20/i to 50/i long. It is reported that the mineral talc may exist in fibrous form,*' but attempts to obtain talc samples suitable for preparing fibers 20/* to 50/* in length were unsuccessful. The occurrence oi talc as a long-liber mineral would appear to be uncommon. The third set of intratracheal experiments ( Table 4 ) was specifically designed to mimic the dust e.xjiosures of the upper New York State industries and particularly to probe the influence of quartz on the combined or sep arate pathogenicity of the other com}>oiients of commercial talc. The effects of these sub stances may now be scrutinized. fl-l-K lTS O f IAI.C A M I O f ASSOCIATKO MINKRAI.S OX TISS1K / )<>loinih\ --The intravenous introduction of dolomite proved toxic to the rabbits, some dying while the injections were being made and others within a few days. Such animals showed a macrophage reaction in the alveoli by the third day. with perivascular and peri bronchiolar cellular accumulations. Occa sional eosinophile infiltrates were to be seen. The lungs of animals surviving to 24 months showed no abnormality, a condition suggest ing either a complete recovery or a lack of chronic response in the first instance. Scrl'i'iitinc.--When introduced into rubhits by the intravenous route, serpentine dust produced within three months a moderate degree of alveolar macrophage catarrh, with septal cellular proliferation. Dust particles could he seen particularly within perivascular macrocytic accumulations. In the case of the rat there is iu> comparable alveolar catarrh at 12 days, hut there are some macrophage and multinucleated giant-cell accumulations at the angles between alveolar septa. In both the rabbit and the rat small isolated granulomata. composed of multinucleated giant cells, well-charged koniophores. unpigmented macrophages, plasma cells, lympho cytes, and fibrocytes with intermingled capil laries, may he found at 12 months. These foci have a i>erivasciilar and peribronchiolar distribution. The intratracheal introduction of serpen tine in guinea pigs provokes within the first month bronchial epithelial hyperplasia, with submucosal and adventitial cellular infiltra tion and scattered intra-alveolar koniophores. By the end of a year this condition has sta bilized as a chronic bronchitis, with bronchiolectasia and distortion. There is considerable epithelial desquamation, with some papilloma formation. Talc.--When introduced into the rabbit bv the intravenous route, talc produces widiin 319 m. .iKcmrr.s or i x o u s t k i .u. u h .i u h one liiuiitli numerous focal areas of alveolar macrophage catarrh and pleural thickenin'* through superficial librocytic and macrocytic hyperplasia. The talc spicules are universally distributed throughout the pulmonary paren chyma hut avoid the lymphoid tissue, and the .alveolar macrophages do not vet show much talc. At the end of two wars this talc is still present in the .alveolar bronchial and vascular walls, and the intr.a-alveol.ar macro phages now also contain some talc. Isolated loci of marked vascular muscular prolifera tion mav he seen. More usually there is a perivascular .alveolar reaction. Kudangiitis proliieraus is commonly seen in the smaller hlood vessels. Alveolar walls .are thickened through cellular proliferation. A moderate degree of chronic bronchitis .and hronchiolar dilatation is seen, together with bronchopneumonic foci displaying a high proportion of macrophages. The pleural cellular pro liferation shows no advance on that seen at the end of the first month. The rat lung is apparently immune to the effects of title introduced by the intravenous route. Xo reaction is demonstrable at the end of the 1st month, and at end of the 15th month a few talc-laden macrophages may occasionally lie seen in the alveoli. I'radically all the talc introduced is still readily demon strable in the Itimina of blood vessels by means of polarized light. When introduced into guinea pigs by the intratracheal route, particulate talc calls forth within one month perivascular and peribronchiolar focal intramural cellular accumulations comprising histiocytes, fihrocytes. plasma cells, and rare eosinophiles. Dust-containing macrophages form irregu larly distributed confluent pneumonic patches i big. 1 ). W ithin eight months multiple foci of dust-filled koniophores in alveoli surround ing bronchioles and arterioles may be seen, but dust cells may also effectively occupy pul monary alveoli over extensive areas, produc ing a solid effect. Some eosinophile and fibroevte infiltration into peribronchial tissue is seen, and there is some fibrosis, with hronchiolar distortion and epithelial prolifer ation. Where dust-laden macrophages reach 320 Fig. 1.--Pulm onary effects of talc injected intratracheally ( K xperiim nt 0(12--guinea pig lung: re action one month after injection!. Focal accumula tion of talc-filled koniophores within pulmonary alveoli. the pleural surface, a fibrocellular sclerosis with subpleural dejxjsits may supervene. At the end of the first year the pleural reaction is well established, consisting of an outer fibrocellular Layer, a cellular inner zone, and interposed foci of pigment-filled macro phages. The dense perivascular sheaths of cells are now seen to be spilling over into the proximal alveolar walls. Immediately adja cent to the blood vessels is a zone of lympho cytes. and somewhat further afield are some fibrocytes. The hypertrophy of the hronchi olar mucosa h;is advanced further, and there is now some epithelial desquamation and muscular hy]>ertr<>phv. At the end of the second year the dominant residual change caused by the talc is the bronchiolectasia and bronchiolitis with epi thelial catarrh. Marked focal cellular depos its and peribronchial fibrosis occur. Fibro cytes may now be seen to be intersecting the massed koniophores, and a delicate web of uriners an r.ii.c nvsr <>x .ixixnir. nssrr. collagen is being laid down. Capillaries in vade these areas. When particulate talc and quartz of the same particle-size range are combined in the ratio of 3: 1. the essential additional effects in the guinea pig ,,it intratracheal injection of the mixture are perceptible within the first month. The effects consist essentially of a greater prevalence of masses of dust-tilled kouiophores, with numerous eosinnphiles at the edges of the alveoli ( l-'ig. 2.1 ). There is a distinct tendency to alveolar septal cell proliferation, and in the cellular masses alve oli may survive as cuhoidal-cell-lined spaces. At the end of the first year the combined talc-and-quartz lesion may he defined as a lihrocellular granuloma ( Kig. 2H I. and now numerous multinucleated giant cells occupy alveoli at the periphery of the koniophore masses. There is a distinct increase in lymphoid tissue not only in the parenchymal nodes and hilar nodes hut also around the small blood vessels. At the fringes of the lymph nodes there is considerable macrocytic infiltration. The bronchiolar distention and distortion produced by exposure to pure talc, though present, are less marked when the quartz is added. There is. however, more marked epi thelial desquamation, and there is more peri bronchial and perivascular fibrosis. TrcmolUe.--The reaction of the rabbit anil the rat to the intravenous introduction of particulate tremolite ( 3g and less in size). either of the soda-iron or soda varieties, is essentially negative. Most of the tremolite remains in circulation even at the end of the 19th month, though some particles may he demonstrable in alveolar walls and lymph nodes. However, even in the latter locations the dust may lie within the capillaries. Very few macrophages are to he seen, and they are limited to minute perivascular infiltrates of macrophages and fibrocytes. When tremolite of similar particle-size range is introduced into the lungs of guinea K ig 2.-- Pulm onary effects of the in tratrach eal injection of talc com bined w ith qu artz lK xiiennicut yt>2--guinea pig lu n g ). .1. reaction one m onth a fte r in jectio n ; massed accum ulation of talc-filled koniophures obscuring the alv eo lar p attern. It . reaction 12 m onths after injection ; persisting macrophages ; granulom a with slight fihrotic changes and some capillary infiltrations. 321 nrrrcrs on r.u.e n rsr ox ixim.ii. !-ijf. d.-- Pulmonary effects of tremolite injected intratracheallv ( Kxiierinient `JOU--guinea pi lung : reaction one month after injection). Commencing crypt formation in a bronchiolar wall at the end of the first month under the influence of tremolite fibers in length. pigs, utility of the bronchioles are observed t<> have undergone erosion at the end of the first month, with peribronchiolar Iibrocvtic and macrocytic accumulation. The epithelium tends to lie proliterated and to be desqua mated. (ii.-mt macrophages filled with tremolite particles occupy the alveoli immediately adjacent to the alveolar ducts, and some scattered eosinopliiles arc to be seen among these cells. The reaction may. however, lie limited to slight bronchiolar evaluation i log. d ). At the end of the first year tlu-re mav lie residual periarteriolar and peribronchiolar lymphocytic infiltration and isolated islets of particle-lilled macrophages. F.usiunplfiles lie scattered among them. The hrottchioltlr inn eosa .also shows considerable eosittophilia. When the tremolite is introduced in the fi rm of particles up to 2Ut, in length, tinspicules may Ik* seen to lie well dispersed and closely applied to the alveolar walls of the guinea pigs at the end of the first month Numerous macrophages may also lie seen containing such particles, but these dust cells are by no means comparable in size to the giants seen in the preceding instances. There is a great abundance of eosinopliiles and com mencing iibrocvtic infiltration of alveolar wtills. The bronchioles are a little distended and distorted atnl show incipient crypt for mation. The latter change is seen to have advanced appreciably at the end of the first year, and goblet cells are now present in greater pro fusion. There is also now more cellular infil tration and fibrosis of the bronchial walls, with macrophage discharge into the bronchial lumitia. Tlte intratracheal introduction of tremo lite fibers 20/i to 50g long produces marked disease rapidly and extensively. Within one month the guinea pigs show coni]ilex masses of tremolite fibers trapped within the bronchi and bronchioles. There is considerable hronchiectasia and distortion, with peribronchial tihrosis and cicatrization. Many of the long tillers may he observed to have penetrated into the walls of the respiratory' passages ( Fig. 4 ). At the end of IS mouths the result ant lesion is a marked tilirueellular diffuse pneumonitis, with marked hronchiectasia and epithelial destruction (Fig. 5) and vascular anil perivascular damage i Fig. in. This ex tensive lesion is directly comparable to the mature human lesion and is even replete with tremolite bodies, i. c.. tremolite fibers sur rounded by a brown iron-containing protein sheath, showing typical terminal dubbing and some measure of segmentation where it covers the shaft of the tremolite liber. Many metaplastic cells are also found among the macrophages ( Fig. 7 ). There is also a char acteristic pleural and subpleural librocellular reaction ( Fig. 8 ). When particulate tremolite i dju. and less in size) is mixed with quartz dust of the same -dze range in a ratio of Id: 7 and introduced into guinea pigs by the intratracheal route, the immediate effect is much greater than that observed with either the tremolite or tinquartz alone. A permanent lesion comparable to that which may be expected with quartz alone is. however, not established. Apparent!} the healing process, seen when tremolite alone is introduced, also mitigates the quartz effect. Within the first month there is an exuberant koniophore anil nuiltintieleated giant-cell reaction which obliterates all sem blance of preexisting pulmonary cytoarchitec tonies around the bronchioles. Many of the trapped bronchioles are distended and dis torted, with epithelial desquamation and pro- r r r r c r s o r r.u.c pom ox .im m .il iissrr. Fiji. 4.-- Pulmonary effects of tremoliti' fibers Om to 50g Ion** injected intratracheally i b'xperimeiit l.W5--guinea pin lunn : reaction one month after injection>. .1. bnuichiole choked with fibers and debris, showing breakdown of its wall and peribronchiolar cellular reaction in relation to trapped tremoliti' libers. A\ high-power view of parenchymal pulmonary reaction, darning tremolile fiber?., macrophages, fibroeytes plasma cells, and occasional lymphocytes. big. 5.--Pulmonary effects of tremolite libers Jli/i to ?!1m long injected intratracheally tb'.xpcriment ^*>5 -guinea pig lung: reaction 18 months after injection). .1. interstitial pulmonary libroMs, with prevalent cellular elements and trapped tremolite libers. A\ distortion, distention, partial mucosal hypertrophy, partial epithelial desquamation, and peribronchiolar hhro-is. Ms. :-'s&!zi HFl:HCTS' OF t a u : n r s r o x aximal tissue 5'it?- 8---Pulmonary effects of tremolite fibers 20m to 50m Ioiik ( Kx|ieriment 995--guinea pig lung : result IS months after injection l. Pleural sclerosis ami subpleural dominantly cellular reaction around tremolite fibers. literatim). Fi>ci of necrosis are present, and fibrosis is commencing at the periphery. The majority of alveolar walls tire infiltrated with macrophages, and there is some perilym phatic koniophore accumulation as well. At the end of the first year there has been a measure of recovery from the initial exag gerated reaction. Foci of massed koniophores may still he found, hut there is very little reaction around these cells. Necrosis is still seen at some areas. Small lymphocytic sheaths accompany some of the bronchioles and arterioles, and the hronchiolar epithelium has recovered in large measure. AnthophyllUc.-- I lie intravenous introduc tion of particulate anthophyllite (less than .fy in size) produces minimal pulmonary lesions only in rabbits. The lesions are limited to macrophage proliferation and plasma cell accumulation at pcricapillary and intraalveolar sites, and the reaction should he classified as inert. An intratracheal introduction of anthophvllite in this particle-size range was per formed in spite of the essentially negative intravenous result. At the end of the first mouth areas of intramural and intra-alveolar cellular accumulation occur. Most of these are dust-tilled macrophages, hut there are several eosinophiles among them. After one year areas of irregular fibrosis may he seen to surround distorted and distended bronchi oles. Numerous areas of hronchiolar epi thelial desquamation with necrotic cellular plugs in the lumina may he found. There are also massed peribronchiolar accumula tions of koniophores with commencing inter stitial fibrosis. The effects of the introduction of antho phyllite fibers in the less than 20/c length range are comparable to the effects produced by the .fy particles, with the exception that fewer macrophage masses are formed at points distant from the bronchioles. There is a greater tendency also for diffuse alveolar wall thickening through cellular infiltration and a higher proportion of lihrocytes to macrophages where cellular reactions arc provoked, especially in the peribronchial tis sues. The hirefringent particles all seem to lie in relation to the lihrocytes. Hronchiolectasia anti catarrhal bronchiolitis reach a some what more advanced degree ( Fig. ). The long-fiber anthophyllite (20/t to 50/t) has an enhanced and even more rapidly in jurious effect on the guinea pig lung. Within one month it produces a marked and exten sive focal peribronchial libmtic and cellular reaction, consisting mainly of macrophages, lihrocytes. and eosinophiles with areas of lymphocytosis ( Fig. 10). Anthophyllite fibers and spicules are embedded within these cells, anti some may be partly engulfed by giant cells. Areas of necrosis occur. Bronchitis and bronchiolitis with distortion and disten tion are present, and the lumina of such pas sages contain necrotic cellular debris. At the end of 12 months a more advanced stage of essentially the same lesion may be seen. with, however, more central and irregular fibrosis within the nodules of reaction. There is now some hronchiolar stenosis as well as ectasia. 325 V*,, A. M. A. A R C H I V E S Ol /.VP C S T RI A L H E A L T H J 'ig . 9.--Pulmonary lesions caused by mithuphyllite fillers less than 20m long ( Experiment ffNs--guinea pig Jung : result 12 months after injection). . mixture of dust-filled macrophages, fibrocytes. occasional plasma cells, and collagen strands. />'. hronchiolectasia within an area of tihrocellular reaction: multiple vaginations create a cystic effect. When anthophyllite fillers ami quartz are mixed with each other in a ratio oi 11:9 and introduced into guinea pigs, a marked subpleural cellular reaction, continent mural proliferations, and perivascular cellular accu mulations may lie found within one month. Solid foci of macrophages occur, and there is commencing distention and distortion of fig. III.--Pulmonary effect of antlmphyllite fillers --t)M to 5!)m long injected intratracheally (Kxperiment 99.1 - guinea pig lung: reaction one month alter injection I. Section shows rapid degeneration of bronchiole, peribronchiolar dominantly cellular deposit in relation to trapped fibers, hut failure to involve the lymph node. bronchioles, liy the end of a year the lungs are occupied by multiple masses of cellu lar reaction consisting mainly of fibroeytes. though some macrophages are still present. Advanced multilocular bronchiectasia may be found within these cellular zones. An inter esting feature of the reaction, which shows forcibly the modifying influence of the anihophyllite on the quartz, is the fact that, though such cell masses may encroach on and surround the lymphoid nodules, they do not involve them. Small foci of acellular necrosis occur in some of the larger cell masses, but there is no distinctive tendency to fibrosis, such as may be seen in a pure quartz lesion at a comparable stage. t 1151 lit N l h K I - T K C f OK T l t K M O U T K . A X T II O P II YI.1.ITK. AX1I TAI.C The purpose of this exjierimeut was to at tempt to define the relative influence of quartz on a mixture of components which simulates the natural talc product mined in upper Xew York Slate. The study was there- H W h crs <>/ t . ii .c n r s r o x a x im a i. i i s s r n lore conducted in two stages, viz., with and without the quartz. W hen no quartz is included, the initial reaction to talc, treniolite. and anthophvllite is very mild. At the end of one mouth there is slight hronchiolar epithelial catarrh and some plasma cell infiltration into the hronchi olar mucosa. Isolated small foci of dust-tilled macrophages may he found. At the end of a year the area oi reaction around the pig mented macrophages is somewhat more ex tensive anil includes some capillary hvperemia. Such areas may occur in relation to the bronchioles and subpleurally. A little hronchiolar distention and distortion may he seen. 'file addition of 1 4 quartz to the talc, treniolite. and anthophvllite mixture rapidlv provokes massive local lesions consisting of macrophages and lihrocytcs with scattered giant cells. Multiple foci of diffuse .alveolar wall thickening due to macrophage invasion anil septal cell proliferation also occur. In the .air passage* there are incipient epithelial hyperplasia and submucosal plasma cell or lymphocytic inliltration. At the end of a year this exuberant cellular resjumse still persists, hut tihrocyte accumulation is limited almost to being a fringe phenomenon. The distor tion and distention of the bronchioles and epithelial catarrh have also progressed some what, hut the degree to which this has oc curred is by no mean* comparable to the lesions which may he provoked bv either long-liher treniolite or anthophvllite alone. ( (imm]:NT Though one must acknowledge at the out set the limitations of the techniques em ployed in this series of experiments, the diversified results obtained, not only bv ex ploiting different minerals hut also through modifying their p,article sizes or varving the route of introduction or the species of experi mental animal, justifv the inference that at least some progress ha* been made in eluci dating the role played by components of com mercial talc in producing disease and the mechanisms by which the terminal resultare achieved. Thus it seems that the basic reaction to the presence of any of these dusts is a macro phage catarrh into the alveoli, the cells be coming engorged with large particles so rapidly that they remain immobilized anil fail, except in rare instances, either to return to the tissues or to he extruded from the lung via the respiratory passages. It is possible that this is merely a mechanical result due to their large size. ( >ti the other hand, it t* possible that the koniophores are actually paralyzed. They certainly do not tend to undergo necrosis; nor are collagen or other types of fibrous elements stimulated to invade the cell masses in the majority of instance-, except when the component libers are long. The degree to which fibrosis supervenes depends on the length of libers rather than on their chemical composition, 'finis when the minerals have been reduced to 4 and less in maximal dimension, they lave practically no fibrogenic effect. >n the other hand, the JO/i to 5 t l e n g t h treniolite and anthophvllite libers produce extensive re gional fibrosis. I 'nfortunately talc could not be obtained in this fibrous form, so that it is not certain whether this rule applies to talc also. It was observed, however, that talc evokes lihrocytcs. but the presence ot these cells does not tend readily to lead to collagen deposition. Attention must be drawn to the triple localization of the lesions produced by talc, treniolite, or anthophvllite. namely, at peri vascular. peribronchiolar, and subpletiral or pleural sites. In addition, cellular accumula tions having no such apparent topographical relation to the blood vessels, air passages, or pleura may occur. It is possible, however, that these macules are merely examples of the standard lesion cut at a tangent. The lymphatic tissue escapes almost entirely, and alveolar walls are not affected except near the local deposits or when quartz is present tun. The marked tendency to hronchiolar dis tention and distortion is readilv explained when large masses of sharp elongated liberare trapped within the bronchioles or when there are extensive peribronchiolar cellular  YTWY W A. .17. A. a r c h m i s o r ix n r s T R U . u h a l t ii masses of fihrotic cicatrization. 'Hit* mecha nism is less readily apparent when such obvi ous causes are in abeyance. The mineral par ticles could not he readily demonstrated in the bronchial wall except when advanced disease was present. ( )n the other hand, it must be granted that we do not yet know the lower size range of particles of those min erals which may be active. The lack of secondary infection in spite of the marked pulmonary changes observed is remarkable. L'nfortunately the study was not elaborated to include observations on the influence of the talc minerals on the course of tuberculosis. Such a project would be worth pursuing in view of the conflicting reports concerning the prevalence of tubercu losis among human title victims. It would, however, involve a costly inhalation studv. Contrary to expectation, the addition of <|uartz did not materially enhance the patho genicity of the talc minerals. Indeed, there seems to be some indication that the fibrogettic effect of the quartz is reduced by the presence of talc in particular. This may lie explicable on the supposition that if all the koniophores are effectively occupied and immobilized by the talc the quartz cannot influence them to the contrary and thus does not truly enter the body, remaining trapped in the koniophores lying in alveoli and thus truly still outside the body. The lack of a lymphoid tissue resjmnse favors such a simple and mechanistic explanation. ( >n the other hand, the difference in reaction may be more subtle and dependent on chemical or physical interaction between the quartz and the other minerals. While there are these evidences of oppos ing or inhibiting actions, and. as has lieen shown, they are not limited to quartz, there is also some suggestion that in certain com binations separate components may augment fine another. This applies particularly to the combination of quartz with tremolite or an thophyllite. The successful experimental production of a tremolite body provides strong evidence that the Imdies found in human "talcosis" 1 are trulv provoked by the tremolite com ponent of the talc dust. Comparable bodies were not demonstrable in the anthophyllite series. There is, therefore, more than length of filler required to cause them to develo]). This feature firmly links the animal path ology to the human disease. Indeed, this series of experiments elucidates most satis factorily the nature of the human talcotic reaction and the factors res]ionsihle for its production. At the same time it sheds further light on the asbestos problem while confirm ing certain observations previously recorded concerning silicosis. Furthermore, the rela tive immunity shown by certain animal types serves to confirm the general concept of vari able susceptibility of man and animals to disease. SIAM M A R Y The pulmonary response of rabbit, rat. and guinea pig lungs to dolomite, serpentine, talc, tremolite, anthophyllite. and quartz, either separately or in combination, was explored by the intravenous and intratracheal tech niques. Dolomite and serpentine are relatively inert. While talc is dominantly cytogenic. tremo lite and anthophyllite have both cytogenic and tibrogenic propensities. Ottartz modifies the effects of these sub stances. The effects of these substances are differ ent from the effects of the substances in combination acting singly. Talc, tremolite, and anthophyllite all tend to damage the smaller respiratory passages and blood vessels to a variable degree. The long tremolite and anthophyllite fibers produce rapid and grave peribronchiolar le sions. RF.FF.RKXCFS 1. Schepers. (i. W. It., ami Ilurkan. T. M .: The KlTects of Inhaled Talc-Mining Dust oil the Human Lung. A. M. A. Arch, Indust. Health 12: 1*2-197, 1955. 2. llana. K. S .: Textbook of Mineralogy, Kd. 4, revised and enlarged hv \V. K. Ford. Xew York, John Wiley i t Soils, Inc., 19.52.