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=~-aff r tfcres; r:c.~raln-Ue ~s:r: cross,~ G.E. Dagle and J.A. Mahafley (Eds.), ° Technical Information Centsr, U.S._ Departlaent af Energy, NTiS, 1980. 0 0 4v The Dosimetry and Distribution of Whole Cigarette Smoke Particulates in Inbred Strains of Mice: Comparison of a Large Smoke-Exposure Machine. (S€PA) with a Small-Capacity Smoke-Exposure Machine (Yyalton) C. J. )ff.NRY,o C. E. WFi1Tb1IRE.•t A. LOPEZ.° D. R. DAN91E.• y(. Q AVSRY.° 1$ CATON.t J. Fl Sl'OI{MY.t R. W. 1IOtrY®It:AG.t YI. R. GLiEB>1V,t emi L E. gOIJNe °Departmeffi of Bsperlmeatel Oneoiogy ead Dopaetment of 9ioahemieal Onmlogy. 34(atobw1ogicel Aeeociatoa. Bothuede, Maryiaad: tAnolytteal Chemdeay Div®ion. Oa7t Ridge National Lborutory. Oak Ridge. Tennaserie AesMACr The diepwieton and the intensEl distribution of total partieafate mecWr (TPM) of aigatette smoke were esamned under conditione of high TPM deposition in the lunqe of miee. Two differeat. smoka-etposura systema aara urd. The smoka espoaute taeehtae (SEd1 In is a la,gecapaetty (480 miae) dynamic system in wbidi uaoko 4s routed through the aNmad containment vnie as a coutinuouolq lloving maem. bqee ata nseeaithd about the nedt fa stock-type holdets for naroely eapoaure. ':te Walton 1loraontel 9mokinq 1llaehine (Walton) is a tmell-capscetp (12 to 70 mies) smtia systsm ahare the smoke is introduced ioto e:poture cherobers into which mxe (resQained in either atock-eype holders-or sbole-body tnhea) rapir'e directly. Both macftian wene operated under oeandatdimd conditions for puff duradoo (2 see). averap)e putT volume (38 ml), puff froquoncy (owe per minute), and butt length of c4arorte (33 mm). . rndioactive nacer (' `Cdabeled dotsiacontane) ema wed to auaatjtate the depodtion of 'CPM in tiesuea of the mawo after esposure to smoke. Whea the Walton maehine wer uNd, the d.positbn of '1'P!1 for 2A1 Kemucky reference cigarattes iaeraa.ed with inceeaein; smoke coocenemation and ,mokre:poaure time but wae indnpondent of,mt or tttaio of neuaea Detectable Ie.Na of'PPi41 +sme found in the head, laryna» IuoW, and stantaeb. The dittsdretien of 'PP'.11 among tbime tfsum did eot chaage m the total espeeuse time iodaasedd to 300 see or as the amolte con,enttattoa aaeieer.eeed to 14.196 (voLl.ol.) ReSerdlss ot total e:poaun) timu or amoke comautratlon. 73 to 7'. % of the TP94 waa found in cmo IaaQr .nd'88 to 91% of the TPMI vat oontained in tM entire raspieatory tsuct. '1'hua the aooditionf of 10% (aoLlvo!) emoke eoacetutaeion for 300 tee of *Psesent.tddtnse: National Caucer Institute. 8edtesda,.Marpland. 177 -._-Z =-1 H r®o12008' \

ME(YflY EC AL 178 HT®0120082 ., total e:pouue aars chosen for compeefeon of the depoutioe and dietribution of TPM from the two emohev:posure systems. The average depooition of TPM in the lunp of 8C3Fi1Cum mice waa 123 end 134 9C after e:poaure on the Walton and the S0N 11 rmohmet, reaepeetively. CoefIIeienta of variation for a totd of 40 oaieo espaaed on the Walton and a total of 120 mice esposed on the Smw II were 0.20 and 0.00, reepeettvely. The pereent of tonl body dhcribation of TPaf for aaiets4 ettpased on the Walton sea 80% in the luno and 86% in the entire mpiretory -rect; for aaunels e:posed an the S8b1 !Z. 70% was found in the lungs and 88% in the eespiratory tract. Several systems have been developed for the study of the effects of cigarette smoke on the respiratory tissues of laboratory aeimeJs. IY the results obtained from experiments using these systems are to be eatrapolated to humans. the smoking machine must simulate human smoking under reproducible conditions and the particulate phase of the smoke yerosol generared must reach the lunge of the animal. Human smoking can be simulated by a mechine. it rept+esentatave smoking conditions are choeen. These conditions are the averages of several human smoking variables that influence both the total particulate matter (TPWI ) of tobacco smoke and the individual smoke constituents. Four variables have been standardized for machine smolang: puff volume, puff frequency, puff duration, and butt length. Under standardized conditions a cigatette is puffed once per miinute. which generates a puff 35 ml in volume during a 2-sec period. The cigatette is smoked to a 23-mm butt length (Wynder and Hoffman 1967). Dosimetry studies were performed and compared for two types of smoking machines. the Walton Horizontal Smoking Machme (Waltoni and the smoke exposure machine (SEM [I). These cigarette smoke inhalation dosimetry studies are presented to document and quantitate deposition and distribution of smoke 'PPM in cercam inbred and hybrid strains of mice as well as to determine which factors influence deposition and distributior. MATEAIALS AND ARE7'HO OS Smoke Oeneretion Walton Horizontal S-noke Sxpoefere .Nacltine (The WalEon). Figuae 1. parts a and b, shows the Walton, which is manufactured by Process & Instruments Corp.. Brooklyn. N. Y. This mltchine, designated the Walton, was designed to eapose a small number of experimental animals to cigarette smoke under the conditlons of a 2-sec ptlff of 35-rnl volume once every minute. The features of this machine are

DOSIMETRY AND OISTRIBUTION OF CIGARETTE SMOKE IN MICE 179 H T® 012 0 0 8 3 1 Fig. 1(a) Walton Hasizoeml Smolung Machine. Mice aie shown rescnined in the eyiindricai tubes. completely described by Guerin et al. (1979). The Walton provides exposure to standing or static smake from a single puff that is unif'ormly mixed by a rotating fan. The animals breathe the smoke for a preselected time ranging from 5 to 45 sec. The particle size of the smoke aerosol has been measured by methylcyanoacrylate fixatioo. Data indicated that the geometric mean diameter of a 10% 2A1 cigarette sn:oke aerosol (see section on Dosimetry) increased from 0.40 to 0.63 µm during 30 sec in the exposure chamber (Holmberg, 1979). The chamber is flushed with fresh air between puffs. The smoke concentration can be varied by changing either the i

HENpV ET pL i80 HTQ0120084 Fig. 1(b) Walton exposure chamber. One side plate has been removed to sbom the inaide of exposure chamber (C8) with the ¢ooleal-shaped e:posuee ha(ea (1i) visible. Dueing an exposure the cigmetta dome (0') movee forward and automatically iattites the ea8atstte (Cll and 35 ml of pog aa is foeeed through the c(gorette into the chamber. A continuously rotating [en (F) ie required to eenue rapid and uniform mixiag of tbe tmoke. At the end of am exposure intsr.ai. ®olte ia vented through the exhaust port (E). chamber volume (between 384 ard 1150 mll or the number of ci8'are'rum (1, 2. or 3) simuitaneously smoked. For example. in using the 384-mi chamber, smoke concentrations of 10. 20, or 30°5 will be generated by simultaneously burning 1. 2, or 3 cigarettes. Total smoke exposure is represented by total exposure time; e.g.. 30 sec of smoke exposure per minute for 10 consecutive minutes results in 300 sec of total smoke exposure. Automatic Sntqke Expesw+e Machine (The SE.N I!). The SEM II machine (Process & Instruments Corp.. Brooklyn, N. Y.) and animal-containment unit are shown in Fi.gs. 2 to 4. The SEM II (described by Moneyhun. Stokely, and Ftorant, 1979) automatically and sequentially loads, lights, pufis, ejects, and extinguishes a series of 30 cigarettes. The smoking conditions chosen are: puff frequency

OOSIMETRY AND DISTRIBUTION OF CIGARETTE SMOxE oN MICE 181 , HT®0120085 c FGg 2 Aotomatie emolc.-upoeana msehia. (.4SM Q). Ci®atettee (C) ew loaded hom a hopper (HO) into a ea;stlaQ draor hotder (DH). The ItQ(tta (L) automttlq0y ipitei the cioatette. and puff.ir a iaeced thsonah each ciamnte in tuea. Fiaw is eaoW by a aaastontty hed diBeeestiti pieewie ptovMed by the pe.ttiw peasaea io the domo (DO ) b.toaae the i4nftod md.nd tbe buct sud of the aiguelte. Dilution ait (DA) is ioqoduced at the butt end of the cioar.tte. a

CH pig. 3 SEIN 11 espoaure module and atoch•type animal holder. Each doublt-eided module hse the cspacity to e=pose 60 miee at one time. Modules when on the e:posare rack ere held closed by electromagnett; (EM) (Fig. 4). An air seeal is provided by the arins (0) so that either.rnoke or air is delivered through 1he channel (C!1), The animal holders are prtwided with chin reata iCn) k i t i W N . nee spr ng c tS (-i..nd metal Foot grtde IFU). s -i . CO CII\

e l ( f DOSIMETRY AND DISTRIeUTION OF CIGAREITE SMOKE IN MICE 183 Ftg. 4 SEM II expoaure tack with eigbt expo.ure modules. Tho .yetem hs the capacity to expoae 480 mice at one time. Oyee ddt is visible Ya this photograph. (one per minute). puff duration (2 sec). average puff volume (35 ml), and butt length of cigarette (23 mm). Thirty cigarettes are loaded into holders fitted on the surface of a rotating drum (Fig. 2). The drum advances one bolder position every 2 sec, which results in all 30 cigarettes being sampled every 60 sec. Air is forced through cigarettes by a constantly held differentaal pressure between the ignited end and the butt end of the cigarette. Variable amounts of a:r for diluting smoke can be introduced at the butt end of the cigarette. thereby producing a range of smoke concentrations from 5 to 100% HT00120087

194 MENAY ET AL which can be offered to test animals. The diluted smoke flows at a predetermmed race through a progismmable distribution valve tltat sequentially directs the smo1E®. at precise time inteevaia, into one of four channels leading to the animal-containmenc units or to an exhaust system. Air is provided to the channels in the absence of smoke. Each of the four channeis has the capacity to provide smoke or air to 120 mice ac one time. Cigarette stroke is delivered to the test animals within 2 sec after generation. The particle size has been determined by mechylcyanoacrylate fiaation and was found to be log8ormallydistributed with a geometiic mean diameter of 0.34 µm (Holmberg. 1979). In the scudias presented here, two of the four cbannels were used. Smoke was provided to one channel for 30 sec while air was provided to the second channeL Ac the end of 30 sec, the smoke and atr were reversed by the distribution valve. Smoke was vented to an eshaust system for exposures of less than 30 see. Total sffioke- eaposurs time was 300 sec (30 sec of smoke esposune per minute for 10 consecutive mstturxs). Aniraola Male and female BC3F1/Cum. 86C3F11Cum. C5'TBIl6 Cum. and C3H/Anf CUat mice were purchased from Cumberland.Yfew Farma (Clinton. Tenn.) at 4 to 6 weeks of age. Male and female DBAl2J mice, 4 to 6 weeks old, were purchased from The Jackson laboratory (Bar Harbor, Vlaine). They were housed 5 animals/cage (stainlesa- steel cages equipped with plastic fivnts and filter bonnera) on corncob bedding (Bed-O-Cob, Chesapeake Feed Co.. Bedtsville, Md.) and were aL'owed Iee access to Purina Lab Chow and water. B,acks containing the animal esgeP were kept in a room at 70 to•T4°F with a cycle of 12 hr light from fluorescent lights and 12 hr dark. The animals wQre initially exposed to 120 sec of 10% 2A1 Kentucky reference cigaretre smoke (see section on Dosimetry) twice a day with a 10-min rest beta--r 4sp_m*es. Eacn day both sessions were increased by 30 sec each until a total exposure of 600 seclday was achieved. Mice were exposed daily for 600 sec for at least 8 to 14 weeirs befora any dosimetry studies were sciteduled. Anhoel Notder3 or Re»atnts In the Walton machine, mice are held in cylindricsl tubes that aliga the heads of the animals wrth the conical-shaped openirgs on the etpoaure chamber [Fig. 1(b) ). The nose of each animal protrndes into the chamber [FiQ. 'ta)) . Twenty mice. 12 hatnsters, Hr20120erc-8 f

~ - --- -- --- - - •, _... .. . .. _ _-- ~-- -__. --_----------~-- - 00SIM@TKr aNo o1S'rA11BUTION OP CIGI+aeTTB SMOKE IN MICE +e6 Hf19Q 12 0 0 8 9 l or 6 rats can be exposed to smoke simultaneously by using this resteasat system. The animal contamment system for the SEM a is shown in Figs. 3 and 4. Aauaals are held in a stock-type nolder (Fig. 3) with a neck slot and restraining spring. A chin rest ensures that the nose of the animal is aligaed with the conical-shaped opening of the exposure module (Fig. 3). The nose of each animal peotrudes through a dental rubber dam diaphragm (Proc®su & Instrunents Corp.. Brooltlyn. Y. Y. ) which forms a seat to prevent body eaposure. When adequate air and/or smoke is provided to the exposure mcdule, restraint twice daily for up to 3 hr results in no mortality and no obvious ill effects to the animals. 0a9matry Kentucky reference 2A1 cigaretees ( University . of Kentucky, Lesangton, Ky.) were used tlsroughout these studies. Each 2A1 agatette detlvered 40 m8 TP'ar1, 0.5 mg mcotme. and 7.7.3 cros carbon monomde (Guerm et al.. 1979). Cigerettes were selected for use on the basis of weight (L12 - 0.10 g) and resistance to draw (85 s 5 mm H;O). Cigaeett®s arete labeled with [" C]dotriacontane ([' ° C] DTC, elmerican Radioclwmicel Corp., Tanfotd. Fla.L either at Oak Ridge National Iaborarory IIORNL) or at Microbiological ?ssociates (MA) by previously published procedures iCaton, 1979). For the Walton studies the 2A1 cigarettes contained 1 to 2 µCi of [`° C] DTC per ci5,arette, whereas those for the SEM II studies contauied 0.25 to 0.5 mCi of [' + C] DTC per cigarette. For dosimetry studies uaing ;he Walton, three nmdioiabeled cigarettes were used for each exposure condition. The E7rst and third cigarettes were butaed in the smoking machine equipped with a Cambridge filter (Cambridge Filter Corp., Syracuse, v. Y. ) ta collect the generated TPM. The filCers were weighed immediately after exposure. The two Cambridge filters were placed in 20 ml of pyndine, the TPM was eluted, end an aliquot was talsen for deiermmation of radioactivuy and for analysis of nicotine content. The mesaured specific activity for the radiolabeled smoioe generated on the Walton was 50 to 100 dpm (disintagration$ per minute) [" C] DTC per microgiam of TPM. The second cigarette was burned to expose the animels to radiolabeled smoke. As a check of the reproducibdity of the animal exposure from the labeled cigarenes, a sample• of smoke was withdrawn duiing each puff (20 ml total). This was collected anto a Caabndge Blter, the TPM was elutqd with pyr[dine. and the amounts of radioactivity and nicotine aaerR L

:86 MNAr $T AL , determined. In each instance the TPM and nicotine values deter• mined in these p;ab samples were within 10% of the expected values for 241 refererrce cigatettes. For dosimetry studies on the SEbI U. the smoke TPM was determined with an optical scattering sensor 1 H'iggins. Gayle. and Stokely. 1918; Jenkins and Gayle, this volumel placed in the smoke line immediately preceding the animals. Total radioactivity associ- ated with the TP!4[ was determined by withdrawing known volumes of smoke from the sampling port built into the optical sensor. collecting the smoke particulates onto a Cambridge filter pad. eluting the TPM with pyt>diae. and counting the pyridine sample. The countang employed a liquid scintillation spectrometer which used simultaneous internal standatds to correct for quenching and counting efficiency. The measured disintegrations per minute per TPM specittc activity for the radioiabeled smoke generated on the S&lrt II was 15 to 25 dpm of ["C] DTC per micrflgram of TPM. , ?,fter 8 to 14 weeks of adaptation to 2A1 cigarette smoke, the deposition of TPM in the animals was determined. From the.:. [' ° CIDTC•labeled cigarette, mice were exposed to 2A1 cigarette smoke and then were sacrificed by csrbon dioxide asphyxiation. Selected tissues were removed, trimmed, blotted to remove escess blood and fluids. and frozen at -20°C. All tissue samples were coded at MA and shipped to ORNL at =20°C for radioactivity determina- tion. Tissues were thawed and solubilized in an alcoholic potassium hydroxide solution, as described previously by Caton (19791. Tissue samples from mice exposed to nonradiolabeled smoke were used to determine background values. Background values varied among the varfous tissues and averaged 165 dptn for lungs. 155 dpm for larynx. 83 dpm for head, 113 dpm for stomach. 60 dpm for hide, 55 dpnt for liver. and 88 dpm for remaining internal tissues. Because bacKgmunds wera var.able. deposition was considered not signi$cant unless tissues were found to have radioactivity levels three times above bacitgeound and a dose-dependent increase in radioactivity was observed. The only tissues that met these criteria were rhe head. the larqnx and upper tracheaL the luags and lorver trachea. and the stomach and esophagus. The measruements on the larynx and upper ttachea had the highest inberent variation after exposure to either radiolabeled or nonradiolabeled smoke. Tt>js unreproducibuity may be a ftmction of the solubilization ptocedure. The ["C] DTC measurements on the luugs were at least ton times above background. all radioactive samples were corrected for background and • for quenchin;f and counting efficiency, and data are presented as micrograms of TPM deposited per tissue. H IV, 01 200, 50

DOSIMETAY 4N0 OISTRIBUTION OP C1GAR8TT8 SMCKB IN MICB 187 ( F1ESU LTS The effect of total exposure time on the deposition of TPM in mlce exposed on the Walton is shown in Table 1. Female C3H/Anf Cum mice exposed to 10% 2A1 cigarette smoke for a total of 100, 200. 300. and 400 sec showed that deposition of TPM in all tiastass increaeed with increeaing espo8ure time. Such e0osure times resulted from 10-. 20-. 30-. aud 40-sec smoke-expmure intervals per miaute for 10 consecutive -minutea. Deposition was nonlinear, when exposure time was doubted, deposition increasedd more than twofold. The coefficient of variation for deposition in the luln{s from 10 anienele esposed at four different times was between 0.10 and 0.20 (interanimal variation). RRepeat8d exposures performed at separats times yielded a coefficient of vananon of 0.10 to 0.15 (intesassay TA8L8 L EfPect of Time on Aeposition and Diseribvttion of Toe®L Pareictdate Mattiar (TPM) in C3H/Aaf Cum Mice After Eapo6sae to 10% 2Al Cigsrette Smoke ' Total smcke eaposuee.6 an Tione 100 ' 200 300 400 Dopo®tion of TPM.t ItQ l Luxiqa 3210.191 8310.18 )~ 148(0.14) 226(0.17) Iaeynn 1 1 3 22 Flem! 5 8 22 56 Stomach 8 9 24 53 Total 44 101 197 357 • Pereent of Total Body Disuisntfoo3 :ue8s 73 82 75 63 Laeyos 2 1 2 8 Head 11 8 11 l8 Stomecd 14 9 12 13 ResPftsor9 txaet 99 91 88 85 °Potal smoke espnsuas of 100. 200. 300, and 400 toe eesulted dom 10. 20. 30. and 40 see of smeko roUoe.ed by 30. 40. 30. and 20 we of eu. wer,+mctivdy. each migute 'rar 10 eonenluttae minutess fCata are given in tolme of mosn TPM depeated Por 40 mice: eoeMci®no oi Qatianoa an in pnranttiumtr *Percent of TPyI deposited per given tiuue is calculated l'tom the msn total trem 40 mim. HT®012009 4

r fee N6NRY @T a1L varratlon 1. At exposure tlmes of less thm 300 set. the disttibutton of TPM in the body was -, 3 to 82% in the lungs and 89 to 919e in the entire esspuatory ctact. The effect of smoke concenustion an depasition and distribu- tion of TPM in mice exposed on the walton is presented in Table 2. Femsle C3H/Aat Cum mice were exposed to four diffeaent 2t1I cigarette smoke concentradons Ivol./vol.l. i.e.. 5.9. 10.1. 14.1. and 23.3'1e, for a total exposure time of 300 sec. The total quantity of TPM deposited in rde respiratory teact increased with increa:ing smoke concentnltion. in the lungs the increase was linear• with a correlation coefScient of 0.98. The distribution of TPM in the body was similar at all smoke concentrations except 23.3%. Some partmcalav. aggregation may occur at this concentration since TABLE 2 „ Effect of Smolie Coneantsadan on aopasltion sad Dismbution of Total Particulate Matter (TPM) in C3$/Aaf Cum Mice Aft.e:300-ser Eaposuse to 2A1 C%ttette Smoke• 1 Peieent'of smoke cooeonteath IvoL/roLl T1MM _ 3.9 10.1 14.1 23.3 Dapasiemo of TPM.t ue (.upgs 75(0.13) 127(0.14) 186(0.16) 298(0.20) Larynx 2 2 S 54 Hesd 9 1' 28 123 Stomach 12 20 25 40 'btal 98 168 214 $13 Pereenc of Total Body Dntufbaaon; Luoge, 77 "7 '.3 58 Leyna 2 1 2 10 Head 9 10 13 24 Stomach Raspir.toey 12 12 12 a traet 88 68 8B 92 •Smoke exposures of 300 we re.nlted from 30 sae of sefoke to8oved by 30 see of air eaah minuto for 10.eonaseutive mfnutosm t8ats ato given in tams of inesn''P!t deposition from 40 miae: 'coetiieiente of vaeiation are in pateniheau. +*Peeeene of '1'PM deposited per given tidue iA celculated from the m®n total dom 40 mice. HT00120092

c ODSIMBTRY AND DISTRteUTION OF CIGAAE7Y8 SMOKE IN MICW 10 relatively higher deposition was observed in the larynx and head. For HT001200a3 the four concentrations. 58 to 77 0 of the TPM was found in the lungs and 88 to 92% in the respiratory tract. The conditions of 23.3% (vol.lvol.) smoke concentration and 300-sec exposure time was the memmum tolerated nontosdc dose of smoke. Approsiatately 40% of the mice died when exposed to 26.6% (vol.lvol.) smoke concentration for 300 sec (data not shown). Data for deposition and distribution of TPM in three inbred and two hybrid ateains of mice after exposure on the Waltoat are presented in Table 3. Twenty female and 20 male mice of each strain were exposed to 10% 2A1 a8arette smoke for a total of 300 sec. Deposition was similar in all strains, as was the peicent of TPM found in the hmp and respiratory tract. Some differences were observed between male and female mice: male mice appear to have higher TPM deposition. The differences, however, may be related to the higher body wagh in msJea TABLB 3 Pnimomry Deposition of Total Particulate MIatter (TPM) in Five Sttaios of Mice After 300-9ec Exposure to 10% 2A1 Cigarette Smotse• Body Pulmonaey Peieent of total body dlaCribtaton areiptt. depodtioq Bo~emy 14oao® , g of TPM.T 9g Lasg teeet [ C3!!lwnr Ctem Paa110s 20.6 88(O.Z9)e 72 84 9Sa1. 23.2 129(0.16) 67- 87 CS:BLIe Cma E'emale 18.6 108(0.18) 84 79 Maie 19.4 12940.22) 68 80 DSA/2J 7opniv 19.3 94(0.22) 69 79 N1nH ZR.9 L28(0.14) 66 34 9C3Fi/Cam rea.le 1'..1 113(0a2) so 85 AAsN 11.9 133(0.17) 32 88GLP1/Caw Female 19.8 80(0.1i) e1 90 DWa zs.4 89(0.11) 80 8ii •Bspoaura eondit(ona ar In Table 2. @'o:ty mico hom en¢h strain weee .utposed to rmoke oa the Walton nem¢kine. tDe{roaition hae twen normalised to 1096 etooke coneentration bas.d upon the aotemi amok. eaneeutistion menwed during these e:t+asure eonditiona rCoeftlelents of vaeiation are in paeentheefs. ~

1 1410 MeNpV Er AL. H T® 012 0 0~` 4 I The deposition and the distribution of TPM in BC3F1/Cum mice after 300sec exposure to 10% 2,A1 cigarette smoke generated on the Walton (40 mice) or the SEM U (120 mice) ase found in Table 4. The deposition is similsr, particularly in the luags and respirstory tract. The distribution of TPM is also similar•. 70 to 801% of the TPM wae found in the lensp and 86 to 88% in the respiratory cmt after exposure on either machine. The only dtffetenee between animals eaposed on the Walton and on the SEM Q was observed in the larynx. EIowever, the high unrepraducibility aasociated with meeatue- ments of radioactivity in the ieryna makes this ditferencedifficult to assess. 1Qote-detailed resatts of dosimetry studies pedotmed witb the SEM II are pramted elsewhere (Henry et el., in press). TABLE a Depoeition and Distobution of T'ocal Partiaulate Matter (TPM) in EC3F1 /Cum IvCoa After 300-sec Egpogm t®10% 2A1 C'*tette Smoke Generated in the Walton or 9EM it :Vlacttinea' TtIMIo 34aehine LueO Layna Hmd Stottt.eh Ranpieatoty t,act DaPotitlciLot TPHL ue Walton 123(0.20)t 2 ' 22 188 SFM Q 134(0.09)t 29 il t8 174 Percant of Totat PJody Dtatdbutlan aveiton eo 1 5 14 ee SEM Q r0 is 8 12 . 88 •Fsposue conditions ae in Table 2. Data are given itti terma of mean 'PFYM depoaited per given tieaue for a total of 40 mice (20 m91es. 20 females) expcued on the Walton machine and ot ' 20 mice (30 molea, 90 femal®1 expwad on the S®9 II machine. tCooKiaiaat of aeriation. OISCUM1O(6 Although the Walton and the SEM II generate and deliver cigetette smoke in different avays, the amount of smoke taken up and Its dista5ution within the mouse ate remarkably similar. Standaed smok3ng conditions were used for exFoeure, and the resultant deposition and tissue distribution of smoke particulates. were determined. Table 5 summ.eeiaee the factors esaanined for

DOSiMfsTilY ANO OISTRi8uT1ON OP CiGAFETT6 SMOKH IN MICE TaaLS 5 Factom Fsamined for Pos®bie F.geet on Deposition and Dittribution of Totat Patticulate Nateer (TP'.4l) in vlice after Expoeure to Smoke 191 Factor Fsporimeetd .Yec®m uead Dago,iuoa dep®od.nt Senote aoneeatesdon Waltoa; S8d! fI Yea Sqaoka.aposure tima Walton; S$62 [I Yeg Cigoratte typo S8M II No Sttain of enolma Walton No Se= of mouw Walton: SE6S II No Ago of motiee 9EM Q No Pnor espmto of ineqma to.moko SSM B No l possible efiecta on deposition and distribution of TPM in inbred mice. The deposition of these smoke particulates in inbred strains of mice Wae dependent on the time of smoke eaposure (Table 1) and the concentration of smoke aerosols (Table 2) bl:t was unaffected by the strain of mouse (Table 3). sex of mouse. age of mouae, or prior exposure to smoke (Henry et al.' in pres9). Moreover, under similar esposure regimens. deposition of 'I'PM was shown to occur prEmarilp in the respiratory Irat:t of the mouse (80 to 9096). with the deposition in the lungs representing 70 and 80% or 134 and 123 ug TPM per mouse (Table 4), respectivefq. for the SEM II and the Walton. An apparent difference in deposition between the two smoldng machines seemed to be higher levels of TP:V: observed in the larynpal tissues from animals esposed to smoke generated on the SLM 11. However. the high backgroumd radioa:tivity and the laege interanimal variation make this difference difflcult to assess. It may be that this difference in laryngeal deposition is related to the apparent differ6 ence in particle size observed on the Walton as complued with the SEM 11. Deposition data for mice expoaed to cigarette smoke in these studies can be compared with data for other species. including man. Data for humans are frequently given as cumulative TP:VI deposition after the smoking of 20 cigarettes. In making auoh a comparison iBitma. 1977), the amount of TPIYI deposition in mice in these studies was approximately the samd as the TPM deposition in a human who has smoked 20 cigarettes (1 pack). That is. approai- matelq 6.8 mg '1R:VI/kg body weight has been astimated to be Nr®012o095 1

( c \ 192 w6NRY ET 4L deposited for a human smoldng 20 cigarettes. The studies presented hero for three inbnpd and two hybrid mouse sttaias exposed on the Walton estimate that between 5 and 8 mg TPM/kg body weight is deposited after exposure to one cigacette (Table 4). Recent data flvm our laboratones suggest that at least 3000 sec of exposure to 2Al cigarette smoke per day (104'0. voL; vol. ) can be presented to BC3F1/Cum mice with little resulting toxicity. This exposure would fepresent a deposition of approximately 1.0 mg TPM lung- ' day- °. Long.tum toidwy studies with this regimen of smoke exposure are cusreatly in progress. ACKNOWLEDGMENT The authors gmtefiJlly acknowledge the support of The Council for Tobacco Reseasch-4J.S.:1., Inc. REFERENCES Rinos, R., 1977. fnhalatioa Toaieology Studies on C'igarette Smoke. IV. Bzpne- eion of the Doeo of Smoke Pertit;ulate yletaeial applied w the Lange of Esperimeata] amareb, Tox+e.ology. 7. 1P9-195. Caton. J. S. 1979. A Yleehod for the Detarminanon of Tobacco Smoke Lohelation Doatmetry Using 'j~C•Labaled Dotnarontane, in Ta6arco Smoire lnhalation 8ioamy Ghento" , M. R. Guann. J. R. Stokeiy. and C. E. IiEegi® ( Eds.), DUE Report ORNL•842a. Oak Ridge 4atioeal Lsboratorv. IVT1S. Guotin, 5if. R. J. R. Stakely, C. E. Hlegne. J. I{. yfoneyhun, and R. W. Holmberg. 1979, Inhalation Siosrmy Chemietry--Walton Horisomal Smok- iag Mnchiae for fuhaletjon Expoatuo of Rodeets to CqatVtto Smoke,l. Yarl. Cancer Inet.. 63(2): i•11-i•i8. Hoaly, C. J., et ai., 1980. Deposition and Diutibuoan of the Total Perticulate Ylattor of Cigecatte Smoke in Vlice Geuerated by a High Capaatty Smore Fsposure System. Twncology and AppUed Pharrnaeology. in pr.es. Hlgoas. C. E.. T. X. Geyle. etAd J. R. Stokely. 1978. Sensor for Detection of Toboaco Smoke Perticulatee in inhalation Exposure Sytteme. Benr. Ta6akforeN. fntern.. 9( 4): 188.2 81. Hbimber4, R. W.. 1979, Detemmnatioa of Particle Size in Tobacco Smoke Iahalatioo De.iees Using Methylcyanoacrylate F(oitlae and SeanninQ Mioevs. copy, in Tobaceo Smoke inha/anon 8batwy Cneettstry. A7. R. Guerin, J. R. Stokely, tmd C. B. )tigoim (FAa.). DOE Report ORNL-6d24, Dok Ridge National Laboracory. YTffi. Monoyhnm, J. H., J. R. Stokaly. and L PYotent. l9'9. Peofte and Inetrumente Corporation Antomatic Smoke Fspotare MaciJne-SEbi II, in Tofwceo Smoke ln/Fa<otion Bi'aaetor CAanttetry. bl. R. Guet+n. J. R Stokely. and C. E. Higgies (Sd..). DOE Report OttNL.•IW2a. Oak Ridpe *tetioaal Iabotstory, Wyoder, E. L., and 0. Hof&mn, 1967. Tobacco and To6aeao Smoke. pp. 94-130, Academic P+as, Nocr York HT1012009G