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NAALNEDICAL RESEARCIAH INSTITUTE L UNC1SSi.±..i

NATIONAL NAVAL MEDICAL CENTER .*i BETHESDA, IMARYLND 20014

VASCULAR INJURY DUE TO COLD - Effects of Rapid Rewarming

SMedical research progress report

Harry X. CARPENTER, M.D.;- Lloyd A. HURLEY, M.D.; Esther HARDEN•ERGH*, ScD; and R.Bland WILLIAMS,- M.D., Bethesda, Md.

SAt#POay CArc - 7F'AG i zAPRIL 1971 26

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ARCH PATH-VOL. 92, SEPT. 1971 BB O-DZCI.E AND SUR"G: "'Y W."( ')' WASHING-ON, D. C.I \ *

I In experimenteil frostbite, more severe in.ury is seen in alowly r -eils-saes than in rapidly thawed tissues frozen for 0ne s-=e ien.-h of -- Q 7-. e nof healing Aenhch follows -a given exposure t=e depends upon he manner or rhawing,the area sectioned, and the duration- of freeze.g. .-... e mos .striking histologs ....ferences between slow- and rapit-thawed tissues occur in Zhe endotheiinn, I.:Zert-a _elastic lamrina and media. Following slov thawing, the ezdothelial cells --re all-ostcompletely shed into -he lumen. The internal elastic lamina is disrupte- ann, ns

early as one hour qfter exposure, exhibits areas of decreased sta-nabilitY. T.e edl-ial muscle cells are distorteG and twisted. T1he media progressively loses :ts normal Aarchitecture so that the end picture is that of !iq.ef&ction necrosis. Foll±owing Arapid thawing, the endothelial cells remain attached to the intina. Three days nfrexposure, these calls are hyperchromitic and actSval. _roii eracing and the nea•icontains numerous hyperchromatic cells. By six days, inti=! 9oiferation is readi-ly apparent and the internal elastic lanina of. rapidl thawed "rteries rand Aemonstrates only occasional areas of loss of stainability. aThe -d -al muscle 4

cells are much less distorted and twisted. In 6omnarison to sho -h-wen r!asues, the -

initial injury appearz less severe, and repair is initiated earlier and = .. .ore co=-plete. This is not without complications, however, 4n that reactive i-•,n U polif-

eration appears to progres3 to partial or total occlusion of h.e involved ves~e~s.

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Cold injuryaý-Rapid rewarmirg i I _Endarterit-is

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Reprinted from tL~e Archijve3 of PathologySeptember 197l1 Voluin? .92Copyright 1971. American; Medical Association

r vascular Injury Due to Cold

flalY 11-C-Pnte. 41).L4ýd A HufeW 1D: Eslrrfz',rIidenbergh. &'D; andR-. Blad lWilliums. MD. Bethesda. Aid

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AY1972

153

Yascular Injury Due to ColdA[ffects of Rapid Rewarming

Harry M. Carpenter. MAl); Lsoyd A. Ihrley. MD: Esther tlardenbergh. SCD: andIt. Blarnd Williams. 1Il. Bethesda. 1id

In experimentally Induced frostbile, more sw- There is little doubi that vascular altera-vee njury Is seen in slowly thawed tissues lions play a role in the development oftha in radly thlaed issue HI4toloi changs tissue necro;is following freezirig injury, be

senbed hem show vascular reaction which it by direct injury to the vascular tissue orcorrelate wM tisue survival s itdes 'the experl- from vascular reaction to abnormal metaxo-mental I e was sna k ! u lites rehased by other damaged cells. Th-rabbit hln• Nub. foloe by eihe rai to-warmbbi (ho walmb ) or l powe aney s Utaw f* following is a report on a histological study

at room leinpfat"ur. Following Slow tlaweitl of ,ascular lesions in the rabbit foot exposedentledtlial cells aalmost comnkely t ed in- to a standard freezing injury. and on Cteto fi lumen, th internal elaslc lamma Is dis. effect of rapid and slow rewrming on therupld. and medial cefs we distorted and recovery from the injury. The histologictwisted and eom necrotic- Following r findings support the diiical observation thatthaw cells atached 1o the rapidly rewarmei tisýe has a better chanceIntima and ar actiV Proweraft alter Vre of survival than slowly rewa•ried tissue.days, the ktern elastic laonan remains intact.and *eda@ ceft are Iess distorted. The initial

-nur of rapidl fhumed tissue appeare less so-Maesi oMtarwre; reneir Is kntaW02d earlier and- is nore com.lpkf• Swvft weoI tartvi varying degrees Adult aliino ralabfis wtighing more than 2,-

of k adaderitif obliea. .500 gm •.'e uted. Uyidbr pentobarbital sodium-anesthesia. thes animuas %%Pre subjecd ti a

tandt•rd freezing injury, the details of vhichhave previously been pubLisher.G In brief, the

THE BEST treatment for frostbite is now limb of ea-h animal was e¶[,vsed tea freez-beliemed to be rapid rewarming of the inz mixture kept at a temperalure of -15C.

affected part in hot water (42C). It has The duration of frrezing ,• indic'ated by a

Sbeen shown experiienfllly in the laboraory thermowouple leratee -rrp Athin the inters-Ihat of the many trmltmetts tried. thb, one .sw~ous spice betun the .ecotu and third meta-reults in the mnmst tiL-e survival. Much of tarmil Iows (Fig I). The animals uvre dividedthe evidence is summairized in revicw, itti- into ((war group4 as indlicated in F'ig 2. Inck.,s by Lewis, ane. Lapp and Joergens.-- gn-ul)4 I and 4. thx- frozen foot uwa a~llumed toClinical ob*.ervalions seem to agree wit'h the Maw-• in air at room temper,:iqre. %*hile inLaboratory findings'z How rapid ri'warming grou;K 2 ari I tbi! f" •ats inmerwd in :aproduces abeneficial effect is. not reasly =nter Ifh ,at 42 C immediately utan remnlpluces aOah netfici " el y is cold hath tand kept in the hath until

know. atbo~h o~e ac!.r ay h ~h! P thre foot tempacrature reached the l"-%v of theduct.ion of maxima) blood flow in the inr-tred ;he font temperature A ll aml , vre;animal-,• rectal tempexrature. All an•1mnls Arre

area brought about by the dl|ating effect of gven aqueous penicillin G benzathine and %rrehbet on the blood els at the time of returned to individcal ragea. Two rabbifs eadhthawing. of group; I and 2 ikvre killed at Mte folio•aing

,ftvpted for ridl•inn April 14. )971. infemn,'lq after eirlnsure: 15 and 30 minutes: 1.

FoM. the dcart•, In- of tgltolog• and phT4cin. 2. & 4. 6. and 12 hours: and 1.2. ' t. 4. 5. f.. 9.gy. Vs-tl NMedira Itrevreh Inmituta. Niticnal 16. 1$. 20. 24. 30. a.id 40 days.t Eleve-n -and IS

Tahel MCdiml Center. l the, -kL, .M t ain.imals of groui" .1 and 4. reseextihvly. -. ýr-

The 'winits of the writer andire not included,. mmediately after death, a 2-cm tis-be wm!-tthe*d atA i#Timia or rtfhewin the vi of SUP 1+-k- ics difseteod from the meta'a Malthe' Navy Dlqrp-ment w the n.aval ,•rnirt-.at m•i-m. area of the pLantar surfame of the fo&i and fixed

lieptint mi'4•t.t o E.',mnwrnal libu'ii'r'. in Ifr'; neutral frrmnaldehyde sol•tioti (form,-Nyavafl Me.led a. 'I d ".hilD. }l. nitm tin). ont.al se-tions rame from the oppositetvfical (ia nter. from r d stwk- ani.manl.l•"•h-Lfeel! arid fronm randomly sel-cted slt'k animals.•

Sections of the fixed tissmse were staincedwith hernatoxylin-erwin. Malfory's jihosJpho.tung-stic acid-henuttoxylin. Mfason~s. VIerhoell',,

staiti for elastic tiksue, and the PAS technique. C

Reatits 4-IGross Observatiom-,Upon remoaval fromnf-V54-'LNthe freezing mixture, ...e foot was observedto be frozen up to the line of immersion (thetarsal-mectatarsal junctionl. T7he involved 4portion of the extremnity appearod wAaxy and:L,;hen andi was frozen sarlid.

In those a.-imals a!!oweti "o thaw slowly(groupi I and 4, the foot temperaturereached a level of -2 C quickly, and thenremained near this temperature for -90 to 30muinutes,. The temperature then rose rapidly

to body temperature level iFig 2). Duringthis rpcgiod, the skin gradually developedafaint pink color. One hour after exposure,the foot was bright pink andi had becone 1

beicame bright red. and the skin war, covered Fig 1.-Oiagramn of rabbit foot shorwing plantararterial arch, site of deep thermnocoujple. and immei-

by a clear transtalate. Due to masisive Me-e sion uine.

Fig 2.-Temperature curves of deep foot tissue, reached batl, temperature, then tha~wed slowly. Timeone rep.-esentative of each of the fom' experimenta! frozen in the bath is represented by crcss hatches.groups, Feet of animfals in groups I and 2 were kept t~me in bath before freezing occurred, by' tutcft linesin cold bath fo.- 18 minutes after freeziog! occurred: slanting up left to right; time out of bath still frozen.thert groujp I feet were thawed 2lowly (air) and group by hatches slantting down left to richt and tini- thawe-d2 feet rapidly (hot watei). Group 3 feet were kept fnren hut below masimumn rewar..;ed terrperature, by open45 minutes before being rapidly thawed. Group 4 feet blocks.were kept frozen only until deep tissue temperature

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Fig 4.-Gross app ranca. of rabbit fcot f,,e lo sev-en days after slaw thaWing (g!oup 1). 'The immersi-Online (arrow) is distinctly delimnited by the gangrenousfoot and digits.

- aicorniplished in four to six minutes. The- skin becitme blve while the foot was Ftill in

the %warm bath and remuained blue for as- long as~ ibe ay. deaand cyanosis

wore much more niarhed after two houtrsthan at the samne timc interwil in slowlytlunwedlius Th 'i 4 were warni. moist.

Fig 3..-4ross appearance of 'abbit foot two to and swollen a~tcr 24 thirdM After three daysi.four hours alte- comnplefion of slow thawing (group tepaagswr nmn iis(uk1). The toot is markedly swollen due to tidema. At. tepaagswr nmn at ukrows ind;Mae fevel of immersier lie. gray and gangrcuons. while the dorsal foot

pad retmained warmi and blue. Five day~sma. the foot assumied fhe appevirance of a1 aftcr exposure, a d..rk. dried -csdiar could beArubber glove distended with wnter i Fig :1). ieeled from underlying viable pink tis~sue.Diring the next (--%v hours. ' he deeper tis- The foot stub remained larger than norm-ilsies gradually ass-umed a blue tinge. On the for over 40 days. andi the skin was red, thin.following d~ay, the skin wavs dlusky red4 and and shiny.irvegularly covered by a grey transudcate. Evaluation of tissue survival -howevd re-The foot ,was weýt and cool. Thle Medeatous -ufts similar to those previously reportedý-:condition plersisted for three to four daqys-, lXE) in groups F and 4. with rno survivalafter which time the fluid decreased in blxow the immiersion line: good in group) 2amnount. The skin then becmie wrinkled and with survival below the iminursiofl lone in allloose. then dfry. hard. and black. The line o! animials. somnetines including phalangeal tis-denvircaition between Ricuk, dry. noutunified sue: and half and half good and poor inAtissue and pink. soft. viable tlissue bilvane srmuls 3.sha rp .af ter five to seven daiys IFig 4 -1. 'Mk=Pwuc Findings.--Sloirly Tlzatrdt

This .seqlucuce of events was, noticeably Tissuecs.-1uring thle fi: -1 hours after ternii-altered in extremitie th:at were rapidly re- nation of freezing, one oaf the most striking%warnnd i grouixs 2 and .1" Thawinz %was phenoinmen is the- progri~sive shedding of

Ar~rh NibU --Vol 9-4. Sept 19-71

156 VASC1JLAI? INJURIY DUlE 70 COLI)-CARPENTEII ET AL

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Fig S.-Top lfDeep plantar n'tusclot and connec- left, Same zs top left but follouwing rapid thaw~ingti~e tissue three days af~er slow thawing (group 1). (group 2). Nowe proliferation of gra~i iation tiSsue andNOte the muscle necrnsis. absence of proliferatort of preservation of satcolemma cell's (hempatoxylin-easin.

gnutontissue, and presence of edema and hemor. x2 4. Iot ti rih. m. tes,"' and time, inlenral.h7e (hcmatoxylin~eosin. Xc204). Top right. Deep as top righL but fo!ovwing rapidi thaWing Igroup, 2ý.

plantar artery from midfoot 12 hours after slow thaw. Endov~elial Cells are for the most part still present.ing (group 1), Many cndodheia! cells are absent, The The media contains curled muscle nuclei and focal

-media contains nectotic muscle cells. granulocytes. areas of decreosed cround substance hernatoxyirn-and erythrocytes (hernatoxytin cosin, x816). Bottom moin. x816).

cndathelial cells into the lumina ef the blood con'tain segm-ental areclt of liquefa~ction tie-vessels. The sequence of endothelial mior- crosis. Beginning about three to four hours.phologyv appears to be pyktn-:ii followved by after termination of cole. vxplo.ure. the %%ali.lomw of vohesion with the adincent intimta of the wwmnillar systemi and the adja~cent'Fig 5. top right), During this same time. supporting ti~susm contain increasing tiur-

the interrnal elastic lamina becomes- Irrveu- hers, of -ohE~y 1rovl6aA rinoctslardy cplit and fral-metited. Incre-ising Ity 12 hours postexposure iFig 5, top right 1.amounts of elastic GteSI lose their affinity exudation is asgociatted with edemai. hemor-for eosin and for V'erhoetrs. stain for elastic rhage, and nt'ros-is thtoughout the wvalls oftissuc% the vmsctllarstei which progress4 in inten-

The media likewhse exhibits4 strikil= sity Fig 6. -top'. Throughout the inuitrdchanges. Curling and twisting of muscle ml- four-hour ixriod, the adjacent tissues -cxathibtdcei is fo~lowed by progressi~v pyknosis, kir- illcrm. iing distortion and wncuolation Of. slid-

MY-AlyS. and k-aryorrhexis. The adjacent ezal muscle bundlesc accontimaned by capil-ground subsuinct± bcomes, increasingly Spale Ltry congestion. After 24 hours these tissuescand %vzcuolated. Tky four hours after cestst. co-tain areas ef smppriuation.tion of cold exposure, the arterie~s and %vins Proliferation of granulation ti ies con-

AIreh Prnt;.-171 Se. p: 11971

VASCULAR INJURY DUE TO COLD-CARPE.'IEn ET Al. 157

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Fi -o etDe ~naratr rm dsctlcye h~acalr~oiw.xO~~~Amlf.Smthe aysatrsob hwn gop1.Nt ci~t stplfbtrpil hst gop3 hnaoyin

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Ho4Le th foaTowo ninlpoiftto.Te a r ctinclsi n ei x1)

Figd &Top lete Deepe eslsoth plantar atrfom.6tt oeczlrs -hin lowyly thtsawed08) tissu v Ulefts. Smarh.- duals afecrsowhaing (gof p the .deoper cpeselasto bu rapidly thawed (gsus rontai) capilatry ing(Femig ofo istm adissocriatd Owat thriee dýP. hemosi.rrha6es asto erlyh Stis boto mi lesfteruwith) Tcop ight oSate adjacp eft sbulta frm ruscl thawing2.uTtheese hezriorrhells are auvl rofrelvNdt theforrale anda ofdetmal pofethe uround Then ing asowly z.thai edli et ine bmoedi ox8 eMeina contansctie tissu e (Fig tT,I fp kfl) an y hour After an oa oprso ewe

spixuk days, necoi excptdo sup-# ratio hare tem raidy uc ad slowly thw d- tissuesin ofvalpssurournrditgngrene of the entre sootrupcnol onxly muhct tucei hPitcupimre mor severelateroltes imerond %ulesin s n-telter.damagw.ederbrvtatu imndirathely efperimental

Ruperiialylmt iraed Tin generalTb edoitei- conditins or-dtohte eq0sivnluf reaton occur

agdto vi the nderepin intimael ofi the planta icsues ta in sl pidly thawevd tissues. uThi~soarcjhlb. Mual feerwi re theseuaatdeepeir vvicu- ranpidlyr &-ats suesiarired in thepllr ribng

landa from~v oand edea na woic the istrrond- isee in raidly thawevd tisuecs, bthe sene ofeJ

eledate ys necrois mnd smernthroycs Thve rapdolyla -hnddg isowno thaed &s triking tha

internl lasfrthe niina prt emains intact, ad abou 6toe 12sec loftm endthlin awl frolierin

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158 VASCIJ.'..t INJURY D~UE TO C0JLD-CAIRYTERf EP? M,

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Frnig 7esTopWed bdeepma phicktiiw Irny a O su ctaoin. changs d0 cL iDeetp pltaroartery 6intkm pmfierato. Tthtis aereno irwoa! thdick- dayesie ater~ vido otwmrj Nac ithte -Tt eatin~,ing Cintrot be1)T~ k ditnushed firw althe natu probterain n20iaI sibro. rrticein.V"a7ldys alterr og endei thawijng. Note ek-4ion.c Dee aiatpry 27 dentteits in (1Ž115 of te ttxiofa bdir" p~eao iina the arbhterasd theL, 7.stz lop ma bitma vreated bw to rdsoefsio vaf x204)-

af "toe brtigrif phoazsxsmr. itini proli, Vfern'.snacispar't tethedy o

_ hmt henha prgrssdothl eIL-a cellsfro the .wnn- Mattul poccnur afot r--pida .few-rm

grup in areieise :ig 6) a. mn I h bottom right)aeir Ozw or w-e acus o n thce ineda or ofeartrie of .Mthe atnd arch-a pro Wn tifle pie swtcviL- suandei tuW tis orm ofetd kv by-c

tarep illnstte in Fig 7. bottom left3. as r4, othal, nth radnalof the artaerin wthese

Unde ocurin tens experimntial twHcndtions ~i nxrpholouS athe ytkapinclasnof the nwdiathere 5 ir n t a ftew imbbis in l, 7i.ntop mayL benre~at~ to ~1reitqmsidnakn ~hof n

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Fig 8.-Top left. Deep ptarta.- vksn 21 days after~ SOttm Sift. DftV Plantar artesy 27 days after rap~idrapid thafi ng. The wal haus Lem~ reqlaced by celli-as thawing. Note the intzv iftmni~y brokm- internal elas-Cornettiv uisum (1 atoxylirncosn. 3<204. Top rig t.m ti arninx (Verhifvtsf slain. x 204)- Baftom rightDeep plant*- artery 14 day,- after rapid timaasiig. Nzae Samre as "o 69Kht Notte the focal ateas of decreasedthe perip1fefal -Ocearý area of medisa with decreased ground rnubsunrve in uhe nedtsa (nernatowylin ecsin.or absent. ground substance (benatorytiuneosin. X204.). X=41.

lar tnittrnes: Itunsquilly distinct. !Ls this pro- mi-t~iton (if exiloscure. proliferation of granti- 2gxxiotimt-tucsm t-~ densitv aLo gradlu- lationatsu is uwd-l untk-r %%-y Anil assevi-

ally Iptx--II. iC~ctwe the Cells -ta that the :uted with svciv-it--mble tzircolenuntic a-ctivitvcell outlinin- once aga"in -jppejr indlistinct Fig Z-1. bOttom kIct IThis scrjuence rget actiml scc~Pion and It is of inlip-ortatax- to rewxognize ftht all ofcleposition %A ground! !,uhsance by nielfa thtese nroce .v --y ml often do occur im~cells. At any onc- time all phamses of this .4vgzmental fass-hion. Thiz .setznental di-stnibu.rparative phenotnenon are apixtrent in a tiont is particulalrly likely to om- ur the nea-rer

given :,rt'rv. In the cnrýe of veins, bmivever. sections arv ilakeu to the igrniersion line-medlial proliferaiive phenouxen. leaid to n-'- Anly gi.ven -secioui maZy .how focal or seg-p-lacemnent of the tmedia by cellubtr fibrotst mental roudions. We hamve seen both intimia!ti:,sue iFig R. top keft ). TWere apear.s to he piroliferntion and niedial necrosis limited to jno incretis in elastic- tiss-ur in either arterivs one si&k t~f an artery or -. ill- An exanmple ofor veins, ('on-mrst-ly, the %vins appeair to foo. I las of theý inf:rinn. cki.4ic lamiina ies

eo~issas- 6tissu. butt we are ituible to sv illustrated in Fis: S. imttlonzcfnix-ther thisý al-o ccc, rs in the arteriesz.

M1rolifera.tive jhenonwnma vce Ais* readilyCwmctiirwxrent in th urc'igsetlmusele It %rasr 4lniwo in similar ea-rlierandi connctfive- tissu-e. Tlhwe ikLws after ter- "eirhmintcnt- that ralvid m irv1 in haid a

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160 VASCULAR INJURY DUE TO COLD-CARPENTER ET AL

Comparison of Skwly and Rapidly Thawed Timu#s dysfunction.- 7.'-1'7 Probablybath factors are involved,

Slowly 7hawed RAptidl, TI)awed their contribution depend-fdsema 30 min immediate

Capillary hemorrhages 1 hr 1% mill ing on the nature of the- in-Oasviiamation of Uniformly present Almost absent jury, tissue-specific gradi-

,enothel~al cells imtt of susceptibility, nnd

ý,.gmentation ot internal Uniformly present Almost ahsent experimental or environ.,lastic lamina nx, ntal __ndtion__. "__

Medial dogeneration Mared Minimal tornd nevrosis mnderatt experiments have shown

£xudation S !Ir 4 hr primary damage in vascularBeZinning prnliferation 72 t- .4 tc 3 hr fti.Je. which can lx- lessened

troblasts _ -by rapid rewarning. Rut,Endothelial regetwer tion A.mist compiely Well estabthshe:i CV' with this hArneficial

absent at 72 hr

Medal pr ,4,feration Almost corapletel/ Well est.blished tivatwtunt, signs of injuryab.'ent at 72 h•' are still pn ent. The con-

Capillary budding sc.ttered super:Cielly Well estadi-hed cept of tissue injury inlthuesat 4 days at 72 hr both the initial damlage and

Gangrene Entire loot Dios on"' the response to the damage.R.os•jonse includes repair. In

bencefcial effect per se on tirue survival, the blood venels earnined. both primarywith ravidly thawed feet (group 3) showing damage and inflammatory and reparative rt-hltter survival than feet which were slowly Tonso•s to the danmage have been obKrved.thaed (group 1) even though the rapidly Other inivetigators have also noted ifss ofthawed fee! wre actually in a frozen state endotieliurn following freezing injury t s.1 •'twice w. long as the slowly -,,awrd. The poor and later endothelial proziferation.; .- Itismue surviv-al in the animals of group 4 is Subendothelial proliferation has also been oh-

nsistent with !he previoLLs obdrmitions. smvd in large vrels frozen directly hnWhile it has ben etablished that rapid cryotheraputic tihvniques .=n

thawing increase tL se ;urvival after frcez- The study has . that rapid rewanrn--ing injury."; the reason for the effect is not ing has -an accelerating effect on the- hislo-known. There is aplvrently son.c effect be- logial sequence of changes which followsides the simple red.ction of the time fro- freeing injury. A correWmding enhail.ingzen. Alteratian of i-v cr*ys-la• size is not a effect has been seen by some in the patho-likely explanation since. insofar as speed of physiologic events which follow freezing in-temperature change affects types of ice crys- jury, such as edema formatimo and rate ofMal fcrmnation, most manmalian freezing in- metawolism3i..sjuries are believed to fall under the category Although ther,! is less fgro tissue losof slow freezing and thawing.7-" Other im- after rapid rewamning, it is ;mfsible that theknown f.tors aLso affect the histopatholog- chronic seqie.lae could be as incapacitatingical changes that follow freezing injury; aq a more extensive 10S of t.isue. Chronicthere is apparently a species ti-,se4pen- skin. nerve. and circulatory alterations ar-dent gradiet of sseptibiity to %*riks frequent clinical manifs-tations of frstbileltypes of injury and to different degrees of inirr0'-'Theprtlifenmthveintinrnl 6angesthe stimne injurny.-7-" For example, lewis' sen in the mao ,ejor in the experi--boherved early degerativv changeQ- in miennts with "-onetinw-s almist complete oc-striated wrmkcle. This %-s not present in the clueion of the lumen, could c-rtainly lead tostriated n.urslc of this serie but ws most chronic .ascular ivr•uliciency.striking in the media of arteries and svins Mention shoul tic made of the ctrol(Fig 5. boltom righti., findings. The ocmurrene of minimil endiar-

Opinions comening the pathioenic ba-sis teritis obliterans in supposedly normal ramof local cold injury hx.-e been divideM 1It ar.erics would unq-tutionahly conpli-Sbet-wen 'nvstigatocs wu.t have empla- eate-inw-stitatiorn- concerrd with studkyingsized damage to the supllating t!l.•t3-: m~inimal degres of intinual proliferation. Aand thmee who vlresz priniary circulatory related drawhock to the uwe of rnongre dogs

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VAMSCI)LAIR INJIJ11tY 111)1 TO-COLW-CAIIPwrNT FT AL 161

RE ~ for the study of -arteriosclerosis has been dent in vasculare and supporting tissues im-recorded,23 and similtar changes occur-in the miediat'Ay after thawing. Surviving rapidlycat.20 However, the naturally occurring en- thawed vessels Jpre,;ent varying degrees ofdarteritis obliter-ans we. have observed is not irreversible endarferitis obliterans. Controlas severe as tha'. observed in rapidly thawed rabbits show a mild, naturally- occurring, A

ves-selsý 14 days after exposure and never endarteritis, obliterans.approaches the massive changes seen after TilwnnirtiorretsrerdtakN#.0) days. 41 02 00 torn W-: liurtus of Mcttidne and*Surgery.

Navty DeparfitlmesLhri ew d

Q11clusiom M*~Th nerT-iawn~ts reportdhed nur mlceaccording to the principles -se utoath in the Guide bei

Gross and microscopic findings in slowly Laboratory Animal Facilit ies and Care prepared byrand rapidly thawed thtsue-s, tinder this set of 'te Committee on thie Guide for Laboratory IInt-i

,Inn R-Ieour Nationl Academv of Sriemot-experimental conditions, indicate that rapid ;n0 RaarhCw-i

URL ~~~~thawing. in comparison to slow thawing. Nttllearleads to (a) ant accelerated inflammatory Nimpupdnary- andreaction, (b) less severe vascular and sup- Th*w Nan*& of DrugPorting tissue injury, (c) earlier healing,and Wid decreased peri-ianent tissue los;. Penticillin G henza~hin?,-RBkillin, Pema-mpes.

Jiistolodzc reactions to cold injury ate 0v- fikillin L-A.

Refernm1. lewis til: lent cold injury. Amner ~J J'hys rat autt nperimnemna? cvntrirlwnioo to the s.tudy of

Mfed 344518478. SIGSZ farslitt- 4 Cardiotare Sor t4945 .W2. Lapp NI.. .Iuegenn JU Frostbite. Mkau Clant I-I. br1mm 1ý .. r ScrE JEIogemN.rat High-at.

Pt.ne 40--r2940. 111-C.s- titode frostbitt. sun's (bune obqt-fT5 a 1n13..1. Vip-himura H: Trietnit of frrtie by- rapid 1s. lark-he It. Ktmlin J:ý llwsiulrgie patniol-

thatd~ng. in Yosh~inum' H. (Mats K. Itch S 4&!s- gique des griuret nmalrwlie dnabont tmcs-motritc. jnvisEssential IProblems in Climatic I'hysdoloj. Kyoto. -thromninIa Meon Ac'ar Chiri GtOG%. V0.TJIapan.. Naniodo J'ut~lding Cv 1.1d. I"0. M& Kr-EVtr I- The de~ve'wmnct of acute t~ass

4. C.vneral dkcus4on. in J'eurerdino of Symposia damage due to rait. Physinl Iem fl- 1 INI'4on Arctic Mledicine and Biiologvý IV. Vaustbite. E. 17. Knlka JI1: MK-wrcirr-ulatow inpignrmenit as aVietrek uit). Fort Wainwright, ALaska. Arctic [acia in inflsmrnatory 65@1a damage. Ann VYAnumed~icat I~ahoratoryý 1NW4. wp 35-47 AMd Sci 116:101PI11144. 1%1A.-A

r5. milks WJ Jr. Fnnrhilc The IIIcm of 1M RIbstmle A: Utter die AMooicbn~~Afanacenmnt and a Reziew tit 2NV Cases, cmntmc4 &knrnn %wch dier Erfdienmc. Ihfet XVILI. DiftrNON-It-SltItWO. XNItIf105.2419: MAD-CVtt02 Anchor. Path Anot 28,'4140-3e t91(k.49age, Atask2. OffIr 4f Naval 11Mvwh-k Drpnýtinent 1-. Ducuing J. IflfTarrcart J1. Fokh _k et it) 1&%ef the Navy. t1*W4. troubles trophiurae% tint nt'rek-nIi~ gwoduits par le

C, Thttmw D. Hanlrtirerrh K: Ki-Te of rapid [moid s- en p~biwaouit & tierarne 4 CMi 55:W54(2.lew rMing on rin'u surival of [ronn r"Wit feet. I iTW4 %pr! I'hyziol ItIS-I M. M!A. 20. Friedman NIL. Kritzker HA.- T1he pathology of

7. iFuhmran F.A. Crirqncn JMI: Studfies on g=- high-altitudie fnrmr'bire. Ajrtie 4 Path t&-17-3-I&.j

!rene foliaminc codi injury. VIrL Treiment of vold 1947.- -~ ~ ~ fljfim ky wanne of imumedfiate rapist ren-rniing. J 1 Sienmdm IT: P'athooirm matoanv an-4 hit-

Glin Inives i647C,-4115P 314-s toogv of Inrat vod injury. in German AniaronI& 'Meryman 147 Review of hiolodri mAt z brju.1Medicie. Wor#ld Iaer I1. 1)~nrtmenn of Airo

ill mmnvan TIT fed): CtlnA'iology. lxaitic Ama- 11(0. %Y4 2. pp 855ý-SCS.uteitvrnk . ltfltW IN 1-10r.. 2.3. Care II Vawixa G. 1(11ev MliE 'rrv-inr

14. Ititltlrmhrmn III- MCdauiir Pit: The [rav-ine. injury to unt o d bkt es'ei in 4Skwr& S4urrerydrirvin and mstoae of mammaldian Ada. 4 EXp flint6178.5.1

2"5454C-S'K HUM, Z- -Mandevifle AF. r~h 11 SICCme VF;-~It).I'imzyni W. WdsAXeu Mh Murki ti-aur ions on the cns4viokg of bkc$ stor Layngo-

stanz in eqxdwrmentat ArnbItt Ann Srtrgs -j ThtZ)-3CI.%L1&l(G4Wr1. I~~t'~' 24. Blair 411. & ibt' Ch, l RD:Sqel t

IT. Nutla 41%: lll"tnlcrsuies in frostbit- cold injuty has io00 pmtsent-c Vol~kn'cp tnten mitaur. in Cold MInjr Transaetiomz .% #Sir 'ers after crnmnrnrev of cOld Zzinjnry JAM1AFourth Cnnkrrnc,-. N11 Fear" Tdt!. New York.ISttftlwt

Jat wt MaC4uFntiatiIun, 1%s pp 9115. 5. Morithend UP.ttle -I: Ounrces ia the Mmar]11 Ix,mi, T. Lovte W&z Vaiwua~r yractkmns Wt the 4wlso apparrAtly haudth rarngrel dhc5 Am.-, S

Akin. to Mnuv 1. !R~u rtoerts of frverinr. of Poda 21CC19415.% 191-5.sw"ijin ami! of saVIn*in. limit I3fl00 LS.~ Unklym Q, haikoiit 1k Afe1wn 1*i h

33.C ErcuetLtrr iKti MI. WIk-tmk et at: Clmini cat. Art- IIIh QS nica

Ar0h Path-!Vol 92. Se~p- 1-9f-PtM!V 0 PýaWt-, z M ifurwState!is of Aee-.ca