Document NG92ygV8Qq2ZV8mvgMD6zRdLD

N jL o t/t / 'j's / *^ VV'**lVW' I'tl'flinUiixl Ar<lrriry*rf |V -f* \*a. a, N''*. n f`rtnt'41 tJJy.A, jirtrcT.ci.y- vr^roi-is in Ji-02. (I Sliiv.rij, o f mwi.-c . Electron C o n feren ce a, P en n - r 6, J'<S2, FV-O. N ew * * j 1 P e n e irc iio n o f C o lo n ic //,u c o s e b y A sb e sto s P a rtic le s A n E lectro n M .c ro c c o p ic S tu d y in R eis F ed A s b e s to s D usi* G eorge E. Westlake, /A.D., Harlan J. Sp]ui, M.D., and /Aarii/n N. Smith, //.A . ><1 Stowe i, c ciianpr-s : an clcc:fc. 4-3: 23r,. ad Stowe!!, .se liver in . the mitoceils. Lab. nd Stowe',1, > of mouse uctural a:ul nes, evtoand micro so m e coii- jid Stowe!!, is in vitro. keratior.5 Lab. Inveil. ,E . Enzya.e liv er degeningle carhoa s. 11: 22,. i R ich. A. A p ro te in E>x- A . 40: 122, i nd N oil, E. protein *)-kosome. .Yr- A recent report by Sclikoff, Churg, end Tissues were fixed in 1 per cent osmium Ilammoriu concerning nsoestosis anc, mes with Palade's buffer and in lithium perman othelioma also ca.icci attention to the rc-la- ganate -followed by dehydration in alco- konship between asbestos and neoplasia ools containing uranyl acetate and lead in the gastrointestinal tract. Ti.ev noted 3 subacctaie. The material was embedded in times ti.e expected incidence of carcinoma 50 per cent Aralditc and 50 per cent Upon. oi" tiiG gastroir*ic?unaI tra c t in atwestos Sections were cut with a diamond knife on workers. I t scented to us th at a reasonable a Portcr-Bium uhramicrotome, stained amount o, aerosol asue.'tos ru^si. dc j,.- wun lead curate mounted on uncoated ptsted directly or indirectly as inhaled p a r grills, and viewed with an RCA EMU-3F uCiCS earned* or. m' e re: dra to ry mucous electron microscope. In addition, suspen uiniiket.to the pi;iarynx.; Actir.3 or, this sions of intact crystals were placed on .5FuIiiption wc ten a svntr tic diet cor.tain- coated grids and examined. For comparison, ;ng 6 per cent chirysotilc asbestos dust to agar blocks containing asbestos fibers were vhiie Wistar rats and cm mined their co processed in the same manner as tissue. ionic mucosas by electron microscopy. RESULTS MATERIALS AND METHODS Scanning for asbestos panicles was fa To study the long term effect of in- cilitated by using the sections fixed ir, posted asbestos wc gave 60 white Wistar lithium permanganate which, because of female rats a syntactic diet consisting of relatively bland appearance of ribonucleic 'JOper cent casein, 65.S per cent sucrose, 4 acid and deoxyribonucleic acid granules, per cent salt mix, 6 per cent asbestos, 2 per made location of asbestos fillers somewhat cent vitamins, 2 per cent corn ok. and 0.2 easier. Occasional asbestos particles were vr cent choline ciiioride. In audition, 12 found near the luminal surface of the ceils, rats were maintained on an identical diet and by scanning of many sections ehwso with Alphacci (Nutritional Bioeheniieals li 1c crystals were detected in intercellular Carp., Cleveland. Ohio; replacing the as- ana interstitial locations. Although the Uutos. Two rats were killed after 3 months direction of movement eouid not be deter u.-.d sections of their colons were examined mined, migration from the lumen inward with the electron microscope. One additional seemed most likely. The particles usually rat was killed 3 days after asbestos had measured from 0.5 to 1 ft in length and had been eliminated from the diet. The colon, the typical chrysotilc structure of two con mesenteric nodes, and spleen were prepared centric tubes.1, 2- 6 Crystals in the intesti forelectron microscopy. nal lumen were coated with a thin homoge Accepted for p ublication Ju ly 24,1005. neous layer of materia', that could also be From the D epartm ent oi i'aiii'i.-'cv. B aylor seen in control suspensions prepared in . rhversity College of M edic.ac, H ouston, T exas agar blocks and thinly sectioned (Figs. 1 D C i Dr. W estlake is a T ra nee in Cardiovascu- lir Eescarch supported by G rant HE-55S4 o f the Natloaai In stitu te s o f H ealth . "This work w as supp o rted b y G ra n ; CA-OJS2S 1 the N atio n al In s titu te s of H e a lth , B eth csd a, Hyland. to o). In most instances entrance of the particles seemed to be through the goblet cells, as fibers were seen in the mucous droplets. Some appeared to be penetrating the cell membrane a t the base of the cell. 2029 NSTiTUT? iC ? OCCUPATIONAL " AND E N V i r . c : i _ n t t l i iTAiTi-J V 5. vr- ! %* 'ir.-. '- S W y^ /j L ^7 .W' y^,/-,V*, y/V /,^ r* - '. / - 7 <-.* . '7. \ "; . ( 1 i tv , /> l ,r ' 'i:` i KVin { fn' i SJ O / / W. , .'` ' l / * . '? , y i V'.'t- : I/O' 'i % 1 c c ft- :*.: / / y - 7 -a 1 71 I x<: o n am ir.' < t, vr y .v .v V " A // <C*-V.^T. H25 co- m ever, : At thiceJJ e 'vit!) j I;.-- . x : *"v }<-.? -;A A . f-: -v` . . }` ? - . * . *a - *. , . ' x \ - -v v x ; - - . X v r ^ - 'i'T ^ v ' X s '. ^ . . *. + m*t , 's **. : ..a ^ . .c- / . . ^ y * y * - v *' : v - V-, * -. ^ A - v -- '% O- i ; J1 I been 1 p.nrl p : Ti.c con.'ifj co'j.'d Z Y : ^ / , .*' ^ *.fc*V . *V - / / ' * *-. -, ' <* r e-i . /*'"* ` -v W/ * l * -*. .-*A* "> ', - * / - V - A ' 2 *'"* :* ^ * ` y* r- 'v ' : . ; * '.-:V.*; - - - V . * , v . . -t - ^ *y , %r- ** . t , ^ 4 ^ s ' sj'"--"A. *j.. ;- ; . v .v '+'J<- 1}, ^iXV -*'>/.f V- \ , V Y- .sc.'# V; :. ``a V/'s'.V-'.^^-v -* \V X-; = -> V ^v c H i "7: .*" <-' w V ;.:- : - v - " -.... , * . y -V ji JjW J. 1 ^^; ' #l ! . S \ y \' .- N >w> the *c< onto i ettemj aminir l'rom t tile f;b not te cutting ta!s w. Z : ' -y ^> K / in le5it ceiiuia: freely \V *, A*_- I ^ * ' *r from ti fibers i i .. tissue i With e XV. - -i - , . . \ - . ; ..- ^ ' Z-C appear, z # v. 1k .V .7 -A - X. / ; J V * * / / v' .- . . r f x . A . Z - / r ; Z :' - . x V e i c n - ^ a **:' ' V I - crystal: ieve t ceils at The m igrate $&&&. v:\C0( 7 A A A ' A A `.vA r : - ; V i-. :" . l \ ` wk** - --i. ^ .*; Pics. 1 TO4 "* `, *` ** . _ i p -SCI i XI io \ perhaps icpri-cnting a ' ha.-c of n igration ^ mui ;>). Sim;. .'.hers found in the cytoplasm of the: eel! v/itli no cn'. isolating membrane (rig. G). A-bestos v.T.5 also found in the lamina propria in both interstitial yi!^*.e!Kc and .'oof.;; mus- (!c cells (Figs. 7 and 8). Section.-, o; the regional lymph nodes and spleen were ex amined with the thought that tho parti cles might he canicd by lymphatics. How ever, no fibers were found in these areas. At'tliis time no alterations in the epithelial cells could be found that, were inconsistent with norma! mucosa. Suctions which had been fixed in osmium were also examined and particles identif eel. Tiie possibility of artifact was strongly considered. Possibly the asbe.-tos crystals could have been forced into the cell during die sectioning, or fibers could have floated onto it from the processing solutions. We significant. Fir-A, *1 ' - r n t y bo a partial ex- pk:nation for a .l u , ' fJi be- tween abe-Aos at a o^roiTiOnjfi of o t ro;r. to -1:n a 1 tract. bk-cond, penotration of er-Y.-i provides anoti or moan for a-pirated fibers to reach the pdoirra and thus produce i r.e- o ti:c-iio:a a , a no: i'.or tum or in which as- Lcstos has been incri The fact th a t p a r trclos seen in this study were apparently ``free" in the cytoplasm and not in vacuoles is not surprising in view o: other pub.id.ed re-ult. Dourrnasii- kin and Dougherty* described asbestos par ticles present in c\ toplasm of cells in tissue cultures as free ar d in vacuoles, and when examining asbestos in macrophages Davis3 also found particles in both locations. In another study, o ir observations on the intracellular reaction to ehrysotile asbestos placed in the pleural space of rats also attempted to minimize this hazard by ex confirm this finding.10Thus, actual incorpo amining a rat after elimination of asbestos ration of orally administered asbestos par from the diet until the feces were free of ticles into gastrointestinal mucosa can pro the fiber, hoping that surface fibers would vide contact between the ceil and a possible not be present and carried into the cells by carcinogenic particle. cutting. Even in this animal, asbestos crys tals were present intracc Hularly, although in lesser numbers. That the observed intra cellular crystals were contaminants from freely floating asbestos is also unlikely from the morphologic evidence. Each of the hers not only appeared to be within the tissue but mo.-t had beer, thinly sectioned. SUMMARY In rats fed ehrysotile asbestos electron microscopy revealed asbestos crystals in many sites in the colonic epithelium and lamina propria. These particles appeared to have migrated through the mucus of the With electron microscopy the difference in goblet cells into the cell itself and hence appearance between intact and sectioned to the lamina propria. This observation crystals is easily apparent. Thus, we be may have significance in relation to carcin lieve that the fibers were present in the ogenesis in the gastrointestinal tract. cells at the time of sectioning. DISCUSSION Ackno'xlcdgvient. The asbestos was kindly supplied by the National Gypsum The apparent ability of these fibers to Company through the National Asbestos nigrate through the colonic mucosa is Mines, Ltd., Quebec, Canada. Fio. 1. A gar-cm) tedded crystal., th in ly sectioned. N o te stru ctu re of concentric tubes a t point where o u ter cylinder is absent (erro-c). Also seen is the varied appearance where the section passed through different planes o f th e crystal {double arrows). X 7 2 "00. Fie. 2. C h ry so ti'e filter in lum en w ith ep ith elial cells on c ith e r side. X31.IOO. F iq. 3. H ig h er m agnification of cry stal in F ig u re 2 show ing th e ch aracteristic stru ctu re. XS3.700. - - Fio. 4. C rystal in goblet cell (crrc.ir). A t this poin t the particle is intracellular b u t is in a mucous droplet. X29.300. i , -j/ -VV.J*J ?i; \ ;.:r| l nm. . t-g> REFE'j p\ *" * 1. Bates, T. P . M orp' ' r.nd cry^'rv! try of 1:1 layer h t `:cc f i l i c z i t s . A m c r . M i r . e r - eloQiil 4 i ; 78, 1030. 2. Bate--, T. F ,, band L. 3 .. n v l M ir/:, 7. 7 . The tubu a r cy-.'.a of c ;iry-0 `.bo fi^bcitos. Science H I : 512, lOOO. 3. Davis, J. M . T h e nitr.V'tructur.u! chans occur during >ri lr:.Ti-.:crrr..at:on of m.'icroph.asc3 to g'.ant cc.'- r.r /i fibrobl.v'.r in et'pcri.-ncn'al c-b p iO n i. Brit. J. E xp. Path. 4 ,': O 3, R33. 4. Dourri'.ariikin, R. R., d D o u e a e rty , R . M . Phagocytosis of crysuakrie particies by cobs grown in tissue culture. E x p . Ceil R e s . 25: 4SO, 1C01. 5. lidding, A. C. E x p erim en tal stu d ies on som e little understood aspects of the physiology of lh :: r<- -pir.itory ad trie ir r \ r. v ;rn- 3Or`. *. e. Trull*. /. i.v /.end. Op ^ / i . Oiffl'i/ytij. C7; /r ,'>, c. \ * fc' f M ., R > r , R. V., and K J'j;;, H . ? . Cb ry-';'.be m o ::> ,o /c y. Amtr.. Mirizruloglil 1>: It'D . 7. Ow cri, W . G. P; " use mesothe!'orr,\ tx- rci-.IlfO to .abicr'os d'u-f in t; ?Tr T'Cy.-jo'c nrc-.-i. Bril. M i d . J O.'/Z i: 211, KOI. 8. t ' c I. J., O i l : .; , J., and H am m ond, 11. C. AW c-tos exposure and neoplasia. J. A . J M : 22, 100-1. A. 9. W agner, J . C , Sl-.ggs, C. A., an d M archnnd, P . D .::u-c pleural me~o:hcl.oma and asbestos exposure in X . W. Cape Province. Bril J. In d h 'lr . M e d . J7 : 200, 1COj . 10. W e sn ak e, G. E ., and S p ju t, H . J . T h e in tracei.'j.ar respond to a^ocstos: an electron macroscopic study. Unpublished data. v;\>J a c j- . ;'.M Thi5 is g ksxxj'.^ priettvopy tperda b? fdixtrCCJ _ of bb;-Giri Uuivemttpjirf p>ti.ryx.rpi-e oi Slud-f Oi to ijc?u o. irsxu-aoc; ` tb* on erfoaL =1 Fio. 5. F ib er a t th e b o rd e r of m ucous d ro p le t a n d cyto p lasm . X46,800, - J Fic. 6. In tra c v to p la sm x asbestos a p p a re n tly "free" w ithin the cytoplasm . X37.100. Fio. 7. Particle (arroi;) in interstitial space beneath an epithelial cell and above a smooth muscle cell. X 37,100. Fic. S. C luster of clu y so id e fibers appearing to p e n e tra te a sm ooth m uscle cell in the lamina propria. N ote variation in density of th e longer crystal as th e plane of section passed obliquely through it. X44.900. '1 f I