l\l e taJJOlism and pos tirrudia tion t>xcretiuu of dt·oxyc~· tidiue

, I I"W IIIC Il SIII• • .J 1:1 \1 t •

'umm urv. - l ufurm atiu n nhuul tho· t' \ t' rt• lwu uf dt'U'\.\T \ticl irw iu

m a nnu a f,. a nd m au aht· r trnuliulwu i • n -,j.,,, •. d. Ul'fl'-~~- ~ titl ifl t·-:l' · rlHIHO·

pho~pltal ,. aminoltydrula~t· a nel tlt•u\ ~ r~ l itl ll tl auHunh~ drola ... c: a t·tivi 1 i• ·-. iu

laumau aud a uirual ti ~,.ut· ... atul h·ul-ut•y tt·~ un · c·urnpa n ·rl. E, idPHI'I ' j ... n ··

purli'U fur tlw e :-..t.; t r n r 1· o f l " 11 indt\ i tl ua l l'Il"~ lUI''- rt·•rwn-.thll· fur th e tlt·a·

m m atjo11 of d t·oxyr:' tiditw ami i t ... lliOllllf'hu:- phalt' in hu man .... P u:-'-thlt·

i m plica t ion~ un dt·o~~~- :' tidirw l':\(' r t• liun an· th " t'U""'I'II. h n ·,.ul t .. t ùat pu-. tir­

radiatiun dt·ox~ ~·~ Liùin uria I'U II ha rdh lw 1' \f H't' ll'cl lo IJI' a "t' II>·Ìii' r biodu­

,..j lll l' l•·:- jn man. D··oxyu ridiru· and t h ) nridi rw 1':\t'n · tiou jn h u ut a n .. b l'furt·

u nd afl t' r lur a l Lhcrapr uti r irradiatiun ,,a., ft• tutd n ul tu •'.\t'et·d l O (J.g JH' r

::!1 Luu r ....

Ria&~unto. (M etabolismo t> psrrPziOIIt' clll[l fl irrttf{gimnt•nto dt>lla de$ossi­t·itidinu ). - Dupu u n'ampia rassq.: na th ·i d at i Li ld iof.: rafic· i ~ulla I'Sc rez ionl'

d d la d n obsit· it idina (CdH ) ("'*) tH·II'u r iua umana '" d i rua 111mifni dopo

irral!~-:iamen l l• . vrngouo r iportati i d n t i rt•lat t\ i <d r onf ro11LO tlt·ll•· alti' itù

tlt•llt· um inoid r ola !'i dd 5'-m onofusfa to d i dt ·'l oH .~ i1· i 1 idiua t' d <· lla d t>SII!'i'- it· i­

t idina in t<·s~:-u ti t' leuc<•c i t i uru a n i t' a u iutnli. l cl a t i spl'r inu·nlal i prft\ auo

<·h l' la tlea m ina?.iont· <l<· lla d c·~n:-.bi t· i Liùin a t• 01·l s uo lllOHofo, fato m · t

lt ·ssut i umani avvit·n•· ad upt•ra d i du1· t'n l.imi dis t inti . Tali falli sono

di l' t' ll !l ~ i in r e!aziorw a l mecrani~> ruo dt·lla t''H'r t·z iorw d i Ùt•so Noic itid in a,

~iunf.:<'IUlo a lla conclus ioni' ('h t· la d e•HI;.~ i c i t i<l inu ria dupo irra~!!Ìamt·nw

non puù <'SSen · a ffatto con-.itl t'ra l a u u '-t'IISiò ilt· òiodos irul' tro llt'j.t li r!l~Ni

uma n i. Si 1\ osser,·ato cht• la quantit ù d i dt·~:~o;...,iuridinn e t imidiua t'Rt' rt•l f'

u dir 24 cm· dall'uom o, pn ma r a nc·hc· t.l upn irra gl!iamc nto terapruli t ll loca le,

m •n supera i l O !Lf.·

(" ) Fc llow of tbc htituto ~opt'rtorr di Suullu. ( **) •\lll~rniation ... ll "<'d: B \]Il\ r-~ lllllllllt i~OOUl~ ru· uri d : Cd H - di'O).~C'y lidiut·,

d(' \ '! l ' d ro -cyr yt idiHe-5'-mtuwrl•o•p hnt<·: til I\I P rlro"~ u ridiu r·:; -mouophuRphate: dT\11' Lb)luidine-5' -ruonnphospbntt•: 5Md.tiH 5- ulr th~ l tlc<r·c.~ c~ tidiuc; 5,\ l <'tiCM l' = S-met h) l deoJC) C) ticl inl'·5' · m(mopho,pbull·; T t h~ rni uc; 'l'd H 1 h) mid 1111": ti uracil ;

u.m dco,.yuridiut:.

4 nn. I MI . SII/H'r • .Son.r ;• ( l9oU) 6. 41l-111.

SH&JIUL ~7

Since the discovery of an elevated excretion of deoxycytidine (CdR) in tbe urine of whole body X-irracliated rats (PARIZ.EK, et al, 1958), increa.sed urinary excretion of severa! pyrimidine com pounds after irradiation bas been reported (DRABOVSKY, WxN'KLEB & SKODA. 1964; 1965; FMaoLM, 1967; Guai & CoLE, 1968; SoLLE & GENSICKE, 1969; DtEN'STBTEB, Aur.EJ'(T & SHEJBA.L. 1966). It wa.s suggcsted that [pOStirracliation pyriuùclinuria (and especially dcoxycytidinuria) might be used as an index of radiation injury also in man (BERBY et al., 1963; ABlE.NT, DIEN'STBIER & SBEJBAL, 1966; CJJEN' et al., 19686).

1'he values of normal excretion of CdR in the urine of rats reported by various authors difl'er very much (reviewed by SOLLE, 1968). Male Wistar rats (200 g body weight) excrete approx. 300 (J.g, females approx. 150 (J.g

CdR per day (including the excretion of 5-MeCdR) (determined on 54·0 males and 70 females: SaEJBA.L, 1966; SOLLE, 1968). A large range of excre­tion could be observed: 30-1000 t-tg per day, hut the daily excrction of CdR by any individuai anima! did not deviate mor.e than 25% from the average value.

Urinary CdR cxcretion after whole body X-i.rradiatioo incrcases li­ncarly with dose from approx. 25 to 200 R ; at lower doses the increase is statistically not signifìcant (SoLLE, 1968), at bighcr doses the dose response curve levels off. Highest excretion of deoxycyticline on the first day after irradiation is ohserved at approx. 500-600 R (7 to 8 fold increase), aher which no further significant increase, but rather a decrease in excretion. as compared with lower doses is found (CaEN et al., l968a; SoLL'E, 1968). Postirradiation deoxycytidinuria is charectetized by a rcturn. to the prei:r­radiation values on t he second day after inadiation up to 200 R and by a clrop under preirradiation values at higher doses. At 1000 R, poslirradia­tion deoxycytidinuria pcrsists for two or thrce days, followed by the cha­racteristic drop on consecutive ,days. ln surviving animals the excrction of CdR is normalized approx. within 15 days (SnEJBAL, 1966; DLENSTDlER et al., 1966).

Increased urinary CdR excr etion was observed ulso in rats after interna! iuadiation witb 00Sr (USPIENSKAYA, 1961; USPIENSKAYA & RAntN'·

KOVA, 1965), 210Po (USPIEN'SKAYA, 1962) and •uce (SoLLE, 1968; SoL­LE & G~~NSICKE, 1968; 1969).

So far litùe is kno~ about CdR excretion in other an..imal species. In fact most authors reported only postirradiation increase in so-callcd Dische-positive substances (STUMPF, 1947) without giving values of the normal pyrimiclinc excretion. The increase in Dische-positive suhstances aftor irracliation was described in the urine of mi cc, rabbits anc.l dogs ( Fro­oonovA et al., 1960), of pigs and sheep (ZxcaA & PosPtStL, 1965) and mou­keys (FIODOROVA & BIELlAIEVA, 1963). Yet it has been demonstrated that

..1 rm. !Bt. Super. Sarul<l. ( 1070) 6, ~6-<ll .

t51'MII EN/.1 l Kll MU Il i

1 )i,.c·h•· · !- r olorinwt ric· nwtbod fur ti w dc·'Lrrminaliou of dc·oxvril, o;,~· i,, tHil

~ui tc•d for rxarl quanlilativc· analy,; i ~ of dc•oxyriltw;itlc•:- i11 nrmc· (~oLLI 1\

~UF.fBAL, J96B).

In prPiiminary cx.prriment;. tht· ran~l' of th•· d ai)~ urinan C'\.f"Tt·Lioll of <.dR (in rlud ing 1\lt'CdR ) \\Ili' fnund l o )w 5-25 !J.g in rui c·c· and 200-700 !L~ in bastard do~-(:- (SnEJUA L. AHtF: NT & KovAniKCHA, 1967). Hr r l'ntly GEH­

BEn &: lh :MY-DEFILAH;NE (1969) r c:porlc•d valuc·;. for CdH cxc:rctiou i11 mi•·• of tllt' saow ordc:r : appro>.. . 20 !J.~ per da~.

BenRY et al. (1963) n~portt· <l th•· e.x.cn·t ion of larg-c· amouub of dcox~ . rytidinr (182 and 52 mg per 24-bour urinr) h~ t wo Lmnun patirnts on tlw firs l day a ftcr thcrapcutir wboll' bod y irracliation with largc· dm<c~~< (238 untl 257 H ). while no CclR could be fomtd in prc irradiation urin.r,.; . Tlw min.imlUJI amo un. l of Cel i t wbirll cou1cl hP dctc·ctc·d in t b e urinf' w a' a p pro'. 4 !LP: mi

Using a more scnsitivt• mi<'rohiologicaJ dc·termi.nation of CdR (0.3 1-LJ.! per 24-hour urine). this compound wa,.; first reported to be prmwn1 in. tb •· uri.tw of healthy hmna:u" Ìll 1965 (Sn EJBAT,, Ann: 1' &: Ot ENSTBJEil. J9(J5) and rxcre lion wa;, fouud llOt to exccrd 4 !Lg pPr day ir t hc·althy indhiduaJ, an.d in paticnt;. suffering frorn differt•nt dis(·a!'t'!' includiug mali~narwie,,

The only cxceptions werc two patienls with acute· m yclotic lcukl:'miu. w ho C'xt•retcd a" much a'i 28 and 44 1-LS per day (SnEJUAT., AluJ.; N'J' & KovAIU·

kovA, 1967). Using a scnsìtivc colori.mrtrir determination of CdH cxtrar t etl from huma n. urin.e (CHE et al. , 1968a) CREN' et al. (l968b) conli.rnwd tL•· excretion of CdR hy health) h umans . ThPy found that itl' avrragc dail~ excrction by healthy individuai>- and canccr patients did not excced 10 {J.f(

cxccpt for one case• of a relativdy high c. cr1•tor (avrrage daily excrl'li on

of 77.5 !J.g). Postirrnd.ialion d1·oxycytidinuria in muu was stuili••d after loc·al a nd

whnh• hotl ) irradiatiou. An inc rca.!H' (two to t'ix fold) ol' CdH cxrrl'linn by tlw urinl' of canct~r pati•·nt:- a,.; rompared to individuai prc·irnrdinticm 'ahll';,

wa;, reportcd br AnmN'T, Dn:NS'l'BrELt & S n E.JBAt,, (l9oo) in ali t·a;.c •:- sLu·

died during local therapeutic irrad.ialion. In most CU$ Cl'l tbc• relativi' incrca"f' wa!> obRcrvcd only on th1· fir .. t or Sl'Cond da y of con.tinuPd trcatmt•nt, whil•· in ou.<' case deoxycytidine wa, excrctcd permancntly s tartirtg ouly from thP third wcrk of treat ment. No corrclation a!'! to tht> elfcctivcness of thì' trf'al­ruent , tumour localization, tbe adrninist ercd dosi' or dol'le rate· coulcl hc• found. An in.crca;.w of 3.2-timc in CdH cxcrction on tht· fir,.t da~· aftcr wllolf' bod y irradiation ·with 280 R was obscrvcd in a palirnt with ac·u te m yelotic l C'ukc•w.ia (prei.rradiatiun average daily excrrtion was 35 !J.g). Ninety mic:ro· grams (80% ) were cxcrctcd during thc· first tbrc•· hours fo llowing irradialion. From the second day tbereaftcr, tbc cxcretion fell below thr prC' irradiation l1·vel, paratlelling a t cmporary improve ment in the bloocl count (SHEJBAL,

1966).

l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l

l tu t

&

un

H·

~ ­

l w Hf 111

"· ~~

1-

u

r­d t'

" .., rt

S HEJB.U. L9

CuEN et al. (19686) reported an approximatcly twofold increase of CdR excretion in 4 out of 5 cancer patients following local , partial or total­boJy irra•liation. In the case of total-body irradiation Lhe increast'd excre­tion persisted to tbc third day afler irrat.1iation.

Tu view of the striking difference in CdR excretion in diffcrent speeies and in order to establish whether CdR could be useful as a« biologica! dosi­mcter» in man, a comparative s tudy of two cnzymes, dcox-ycytidine amino· bydrolase und deoxycytidine-5'-monophosphate aminohydrolase, and of the excretion of deoxyuridine and thy midine by rnan was undertakcu . Prf•limi­nary rcsults of this work were reported bcfore (SHEJBAL, KosTIR & Sl\HO,

1968).

Jifaterials and ,\ifethods

Waterials. - Nucleosiùes anù nucleotidcs wcrc purchused from Calbio­clwm, Los Angeles, Calif., U.S.A. Other chl'micals wc re of G.P . R. grade.

Wistar rats (200-250 g) and chick embry os wrre from Velaz, Lysolajl' nrar Prague and from the own breed of the Jstituto Superiore di Sanità, Roma. Bovine, calf and h og tissucs wcre frozen immediatcly aftcr collcc­t ion from tbc animals at Prague slaughtcrhouse. Human tissucs were recci­ved from the Tnstitute of Palhology, Charles University, P raguc. Human blood was from thc Centrai Bl?od Bank, Prague.

Tissue collection and preparation of homogenates. - Chick embry o and rat tissucs were collected as quickly as possible and immcdiatcly homo­gcnizcd. The coJlection of human tissues '\'as uot possible earlier than lO hours after ùeath. Human, bovine, calf and hog tissues were frozen in dry ice and thawed immediatrly bcforc t he preparation of homogcnatcs or ace­tone powclers .

Homogcnatcs ( l 0-50%>) were prepareù in 0,1 M tris-buffer (p H 7,5 for dCMP-aminohydrolase and pH 8,5 for CdR-arninohyclrolase assays) a t approx. 0°C in a Polter-ElvPhjt:m homogcnizcr. l [omogcnates were ccn­trifugcd at 21,000 x g for 45 min. at 20(; a nd the limpid supnrnatant was •lireclly used as th e l'uzymc source or for thc prcparation of acetone powder a<·eording to a modi.fied mcthod of WAJ,oscmuoT-LEITZ {1924).

fsolation and lPukocytes. - Human l r.ukocytcs werc .i:sulatcd from blood (citrate anticnagulant, prcscription ACD-R LlO, ratio ACD1blood = l j4) of healthy donors, according to thf' mclhod df'scribe(l hy RERTINO et al. (1963).

Hat Leukocytcs w(•re isolated similarly from pooll'ù rat blood ( \CD ' bloo1l = l , 1.5).

rTomogrnates Wt' rc prcpan·d as describrd abow·.

----------- - --

l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l

• ...,l'l Ul. 'Il l Ull .. lillfl

l'rll/"111 dl'/ r•rminllllllll - Tho · ~JIIIUUIII 11! f'tu!l'jn, 111 th• ~tqwrnatalll

alt•·r t't' rtlrilu!!a lwn ul hunto !!t'lt.tll ·~ al!ll at·t•tuu• l'""''' r ~ ~~ ~ l" tl~'""~ "·• ·

tll'll'nutur·d l" Le"' n .. IHI'll•"" ( Lo\\ 10 • l ul .• l 11.i l ). "tllt luuuatt ,, r11111

alhu11t111 ,e• ro ·lo-rr·•" •· prnlt·in .

/ • n :l tllr ' ''"'" '· J)t·u':''' ~ tidllt• aucl '"'"''' 'tidin• ·,'l'· ttltlltuplu•'J'Ie.ll • ami noli\ tlrufa,.e· a t•ti' ti u·-. ''ere· dt•t,.rlltllll'tl !.1 a nwdiht•tl ntt tlwtl uf \l \Il \

&. \l \l t' ( J():i'l l . Tlu uwul•<tt lun llll'\.tun·" tttllt.urll'd:! !..t uactlt·,. tiC:I\I P (•). lo

!J.HHIII•,.. '\a l '. ti.~ Ili O,h utl t'l\7.~ 1 111' und O. l 711 tn-.-hull'Pr pii . ,.l 111 a r ..... , vnluult' ul' l 1111 1'11r dCI\'IP-nriiÌitt•llldrul a'-t' !lclt•rw tll atwn ... autl ~ ~L 111nl •·

CdH . O . .! tu 11.11 Jll! t' llì\~1111' anrl 11.1 " tri"hullo·r pii B.;; 111 a ltual '"111111•

ul l wl lur ( dH-aJuutull\drola .. •· dt'lt•rminallllll•.

l ~tr · uhatiull \\U~ lwrfurmt•t l in l• ·~ t tuili', 10 .t 1\,tto· r hath al :~7••l . u11tl

al 0.1 :i . :111 an d h!l utitut tr· ~ tb•· t'll'l.~ Jllt' rnH'I iuu 1\ :t'- ;. l !I)'Jit ' rl l1~ aridi t iuu ul

:> mi H'l' ·l'uld ;) "., II UO~. Thr· pn•ci palall' \'il "' rt'lll""' " b\ t't ' lllrilu:raliuu

and aftr·r tnn\t·rùt·nt tlilutitm thr uptu-al tlo•n .. Jt ~ "a' n ·a tl a l :!t •ll. :!HO .uttl

~1)0 n m. l h ·uminat io n uf d CM P :mel C1l H '' .~ .. tiPI nmin• cl l11 ti•• cl•·<·n·a· •

of optil'al dl'n ;. it~ ul 290 n m (\1A1.n & M.u.n . l I.HtO ).

Jl' rwt intli1·atc·d otht· r\\Ì!H', " lll't'ÌIII' al' l i,·itu·, art· c''\:pr•·,-.c•d 11 1 11 1 (l.lltlllt • ....

uf tlw ~-~ to,.inc· d1•ri1 uti1 t• .. dt·aminatc·cl in hll mmutt·- J'l'r l 111;.: pmlo' llt

TLc· Sl'll .. ili\ ili \\<l' 311 !J.IIlOlt•'- oli miu ml irwuh.llioll 1111'\.lllfl '. l.f' . apprto'\. .

) 111 !J.IIIHic·-. ltO min l ut ;.: pn,Lt•in.

lh•termi11lllio11 ~~f dPOI\'IIIIriro~>idc· ' tmtl dt•o \\nurlt•lltidn .. - En.t~mat•·

ca li ~ l'uruwcl l 1d H and cli 'Ml-' a uri ur n·-iclual Cci H and tiC~11' '"' rt' clc·t,.rrni ­n,·cl 1-ith / . (/C'tdophi/11' /( 2(1 in hr·al dl'proit•· tnllr 'cl rt '<II'IÌttll 1111'\.lurc· .. alùr

rulmnu ( ll ti\\1 ' '\.·.>0 ) amlur )':Jf'•·r !'ltrom.ttugr.tph~ (n-hutanul-an11no11 Ìa :t• ·

('Orcling ltll\1.\IIK[J\'1'1 ,'\ s~IITII. ]9111). Tlw !-1' 11 ' 111\ÌI~ ,, .... O.:i Ili :wtolr·l ml

r•·arlitllt 111 Ì'\.lll re·.

Tlw dt·t ormiuatiun uf CciH in hmnan urine• ,, , , ., dc ·~nilwtl hc·forc· (!:->111..1·

8.\1. Atcll· ' 1 & 1'\. 0\AIII"-cl\.\. ll.lh7 ). 'l'Le acid t•fllut •nl Jr11m h11th Du" '''·l

and T>ol\1''\.·.'iO ac<·onlin~ 111 thi .. nwt hod. \\a .. l' tiiH' I'rt t ralt' tl h~ :dr~urptiuu

<m cLa rcunl, c• lutìuct 11 ith l' ~ rirlitu· und 'UC'lllllll ,., aporatiun. A liq nnh \\l're·

chrumatowaplwd un \\ hulman u :1 papn (n-lnllauol-antutouia). Band-.

r ·ur rc·>-pondiu~ In l dH (11 1 O.IH) and TdH (Il, tUO) 1u·n- ,.Jnll'cl

\\Ìlh ,,aft-r anrl a .... u~• ·tl fì.r t1w IIPn'\.Hil~t~ ... illr· .. ,,jtJ. /. aridoJIIrifn, H :.!lt.

Tlw lo\\c·~l anwunt ol l IIH antl Tdl! ddr·c·tahlr """ IO i..tg J" ' r :!·1-lwur

llrllll'.

(•) 1lu·•f' Iom -ul.-tr.tlt" <fU.tiiiÌ tu·- "''"' du·toll·il J,, lltt IJc·l.. uf clt•"''"udt>o•ttl•·' .c11cl Ùt't> ,\lllll' lt•fttlllc·- .1\UII.lhlc· for "'ori.. 111 l 'nu~clt': 1111' ~ uro· 111111·h '"''~'' thun tlf'lltllal •nh·

~trate rliiH'I'IIIrJIIIltl•

SHt:JDAL 51

Nliaobiolol{ical determination of deoxyribosides. - A modification of the mcthod of SosKA (1963) was uscd. A drtailed description of the pro­~·cdurc is contained in anothcr paper ( REJBAL, 1970).

Results

Spcci tic actlvitiCS of dC.MP- ancl CdR-aminohydrolase in human tissues and leukocytes are rcported in Tahle l. It can be sceu that human tissues have high activities of both cnzymes. As indicatcd by tbc range of valucs reportcd, activitics varied considerably from case to case, and no correlation hetween proliferation and t he enzyme activities could be obscr­' cd. No :signifìcant rclationship hetween the activities and the time after drath ( Il[} to 24 hours) a t which the tisl!ues were collect ed was found. Tbc products of d<·amination, respcctively d UMP and UdR, wl'rc identifi('d by t·olnmn ancl paper chromatography and subscquent microhiological detec­Lion with L. acidophilus R 26.

TADLE l.

Specific activities of tlCMP-and CdR-aminohydrolases in bomogenates of buman tissues and Jeukoeytes expressed in Wf.!.moles of suhstrate deaminated

in l hour per l mg protein.

Liver

pleen

Bone murrow

Leukocytcs

Ilepatoma

Hepatoma treatf'd with ticà

cytosta·

"pleen with tumour .

Clan d

Spt"cifìc aet.ivitiet

,JCMP- aminobydrolale l ran1e l meao

Cci R- ominohydrolaoe

rrmge me an

270 - 760 520 l 50 - 715 360

130 - 390 250 210 - 580 no 515 - 1160 760 200 - HO 590

970 - 1990 1250 1575 - 3075 2530

250 - 600 HO HO - 120 370

lO o 260 270

o 50

'lumber ol

on•ly.ed dnue1

16

11

5 8

4

l

\lthough acetone powdcr prcparat ions from buman livt·r and <. plePn had, for unexplained rcasons, rdatively low spccific aetiviticH, dCMP - and C<I R - aminohydrolascs wcrc storcd in this matmer bccausc of lack of fresh •naterial. JIO\\I'ver thc activitirs of holh enzy mcs in the ac(~tone !Hmders diJ not dccrca!lc l' ignificantly within 6 months wh en stored at - L)oC, and 4'1\abled -,ome fu rther ... tudies on tbc general prop('rlies of the 4'rtZ~ mcs.

t 1111. Ist. StiiJ Or • .SII >l rl<l ( 1970) 6, ~6-H L.

l

l

l

l

l

l

l

l

l

l

l

l

l

l

l

l

l

l

l

l

l

l

... ··- ~'l'lllll.,a 1 1111 Hlf 111

A ,; s ho\\11 Hl Fil!. l. a ltig'lt lt•mpnatun· ~l'n,.,itÌ\Ì I \ of dC\IP- anuu o-

h) drola-.1· aud a prolfuunrt·d lu·a t ;;tahilit ~ of Cd H ami noli\ droia-.t· fron t human li' n '' a~ oh,.. ,· n l'd un inl'ubation in l'itru.

IOOI •---·~ ----0 . ;901 ~

80~ '

Fi::. l . <t v, 70

"' ~ V)

"1 ~

50 \ i.Oj

ì IO 20

l o-. uf (d H-awiuo­

h~Jrol.t•l' (••ttnt· 1) :tttll

.11. \!1'- nulilfolt)drula•t'

(t'Ili'\ '<' 2) a<'lÌ \'ÌI~ ntt

Ìn<"uha l iuu nf huutau

li, f'r huutn.'!t'u•att· "' ,.,_ lro al :r; u( .

J luma n }j, l'r and "'f!lt·en Cd H-aminoh) drola,_,. i-. rwl iua1·t i' at1·d h~ }w a tiug of tlu• lwnwgl' ttalt• or H<'rtOne powflrr ('Xtral' t t Il 800C for .} lllÌriU11'"'•

" lti lt• al! df.M P-aminohydrola,.;•· aeti,· it~· Ì;; lo,., t undn tl11· !iaru•· I'IIIHlition -.

('l'abk ~). Y<tlno>;; uf dCJIP-antirwhvdrul;.,.,c arti,·it~ Ìt t hourogl' llatt·,; of ';'

da) ebiek l'ru bn o,.. ar1· indt~tl t·d in thc tahll' for rompari•mt.

Tutt.L ''

luflut'JH·c of lu•ul o n dC!\'JP-uud CdR -uminohydrola;;p arti \ il it•,..

\lt·an-. uf J t''-Pt~rinu-ul .. . l luuto~f'u.tl~· .. a nd at·~ruut• IH*''dt~r .~ ,tr~u· t ... 'n·n · lwalPtl for .l tttitt. lo 811•(. I'IIOI('tl attfl l'l' ttlrilu~l'd , , , I I!.HIHI :: lor Ili 111in. Tltt• ""Jll'rn.llant '' ·'' u•ed a­f'lt~~rue ~unrt't', 2- Ju tJ.tun lc-... ~'>uh~o..tra t ~ ... JWr l rnl iuf•uhution rliÌ"\.Iun· . inrululiÌnu linte.., l. IO. l.i . 211. :10 nntl (>() n tinutc••. Spe!'ili•· III'I Ì\ itir~ ur.· P'(prr•sNI in Ili !Llllol1•, l') h•"Ìttt' tk ri · vuth t'l'- dearuinul ('d JH'r l lunrr ur~d ] llf,_:. pru teiu iu rr..;pec·th f• t~ ti Z.' Jllt' p r f' JHtra ljuu ...

l· n ., ) tu t ' .. n u r 1 1

l .i, rr hmttu,.:t•nate

l .ivt>r a('~lflttl' powdt•r

Sp lt·en hortHl!(t'nall' .

S p ken al'r to n l' powd.-r

f.hicl. e11thr) u (o t h da))

l eH ./\lP 1111Ì unh~ tl rul 11 <~t· J-

llll lrl'ltl •···

::?IO

102:;

2%

9i.>

23:111

ti'I'Hit•t l

Il

l!

o o ()

ti Ili II' Ut(•({ lrt'tlti'll

:l:;:; 1:12:; J •)~-..... ;) I!J J.;)

2:10 liUti

1111.) :!9)~

·' '"'- /;t. St~Jt•·• · s,.,.;,.; (l!l;u) 6, 41) 111 .

SHEJU~L 53

As sbown in F ig. 2, the pii optimum of human liver ùCMP-and CdR­aminohydrolase was found to be 7. 7 and 8.5 respcctivcly.

9.0 9.5 p H

Fig. 2. - Dependence of specific nctivity of hwnan liver dC'tP-nmiuohydrolase (curve I) aud CdR-arninohydrolase (curve 2) (acetone powder preparations) on changes of pH of the incubalion mixtures.

Deoxycytidylate anù deoxycytidine aminohydrolases from human liver and spleen deaminate also the 5-metbyl derivatives: 5-.Me-dC~1P and 5-Me­CdR. Specifìc activities for the mcthylated compounds were approximately ~- fold lower than. for the unsubstituteù substrates (Tahle 3).

TARLE 3.

Deamination of dCMP, CdR and the 5-methyl derivatives by human liver and spleen cytosine deoxyribonucleotide and cytosine (leoxyribonucleoside aminohydrolases expressed in m (J.moles substrate deaminated per l hour

and l mg protein, means of 3 experiments.

.. : nsyme ao u rco . •

Livcr acetone pnwder . .

l Sple<·u acetone powrler

Spcc.i6u Acthitiea

C) to.ine deoxyrjbooueleothle umjoohydrolase

dC~lP

1050

955

5M edCMP

575

520

Cyto1lne deoxy:ribumwJèO&ide amutobydrolll,,.

CuR

1250

810 690

:!65

A 1111. l at • .suv or . .S<ttllta (lUi U) 6, 16 tll .

l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l

, ... , •• _,(JJ'\/.1 l llltllttlll

lnlact ht1111an lt · ukt H'~ l t·~ 111 ' " ' P' 'n-.ion ar•· altlo · lo dt•<uHinatt· Cd l{ hut uot riC\1 P. probaltl ~ ho•t·au·t· tlw tlll(' lt•ol id t· d m·· 11 01 Jll'flt ' lratc· tllt' et· li

Jtwrnl1rarw (T al1l• · 4 ). \ ..: :-htJ\1 n in tl tt· lablt· . 11 0 tlt •a tninal ion of' Cd){ "a ~

ob~t·n t•cl 11 ith ,..u,..pt ·n:..: it~n ~ nf ral lt·ukon l t•.•

TAIIU l.

Dt·aminatin{! caJlacity of inla<'l luuuan nncl .rut ](,ukcU'ytp,. towanls Cd}{

and ac~r.r (ran~·· lliHI IIH'IIII" nf (l (''XIIf'l'illl l'lll~ )

l{ l'at'lion mi'<t nrt'• o·o111 :11 .,,.ti .) 'l t no lo·~ •n lo•t ra lo·. lo jlllwlo·· '\ ,ol· (l or oH' \l P-atuinoln ­

tlrol,o•t' :t••a~· ""'~ ). (1.55 llli lo·ul..nr' tt• '"'I"'II•Ìuu 111 Il <1"., '\a( l. loroudtt tu a fiu,tl 'uluuu nf l m l with lunpid hloutf pla-tna. IJt'auuu.Jt 1011 n l (d H wotlo lnuu.uo pl.1•111a alou•· dio l oJIIt

!''\l'l't'ti ~Il 111'./.llltllt'· pt'r prtonf

l n L' ul r .. n u rrt·

Hu111un 1<-ul..o<'~ l<'­

Rat lrukol'ylt''

1 111'-lUt• H<fn'll' •

J •·u\..n,-,,, Nmut .. Jl' r nun • .. u~1u·u .. ,,.,

. l 2911.111)11

12fl.UOII

:1211 . Ullll j 21U :!<Ili (:!h.i)

l iiU . 01111 Il Il

f• Th" Ntz.~mir acti,il~ i~ exprr~lft' tl IH rH/lJ.uo1tl'l ""ub .. trut r tl tilt'UHI"tt•t1 h~- IH ' lu\..oc\·t•·~ fH'r l hour.

As can he sc·eu in Tahlt· S. ali IIHIInnu.tlian ti,;suc·;; tt•slt•d for JCJ\·lP­antl \.d H-aminohydrola,;,. <ll!li v iti l';-. Tl'\'t•akd Jlllll'h lo" t•r appar<'nt at:ti,•i­

ties a~ compan·d with tho:-w in human tif-s ttt 'l'l. Tht• appart·nt aminohnlrolast·

acti' ities in rat tissut's ~\ ert• l()'" t o l 03 ti m c» lo'' t'l' thatl in t h e eorrc,:pondin~ human lÌS!' tH':< . ] n contras t lo human tis!'lll':-, tlH' r!C\1P-aminohydrola,;c

aeii\Jl) in tht> rat tis~ue>' '"'" ;-.i~nificanll~ hi!!ht·r than that of th" nuckosidt• :unin.oh~ drola,..t•. For <'ompari,;ou d CJ\lP-aminuhydro]a;,t• a<· t i­

viti"" of th<' hi~hl~- prolifera ting c·mbryonir ti ..,;,ut· of chicJ.. s j ,. add<'d t o

tlw table. The appan·n t sp <'c•ifi<' a r ti' il~ dt·cn·a:-t·d "i t h t h c' a ge of ti w

cmhrvo,.. The dNermination of CdH ami TdH in tlw urutt· of 8 healthy pcr,.: un~

ami 3 <'ancer paticnt~ bdort· and afll•r loeal tht·rapt·utit• irradiation \\ R•

altt'mptcd. An amount of l (l !L~ dt'OX) nucolt-o:-id e p t· r 24 hour urine could !. till LH· dl'tectt>d h ) tlw mNbod tt"ed , y••t nt•ithn uf tiH' t\\ o Òt'OX) nudt·o­

s idt•" \\as found t u h e prt':H•nt in tlti:- rptan.lil) in an) nf tlw ea~e,. ,;tudit>tl. A;. s lwwn in Tahle 6. CdH ,,a,. f(lund lo lw prt·;-.(' Jll in ali analyzr tl urirw

:-.amplP:; antl. in aecordanel' willt t•arlier fitldin~"· a rertain inrn·a:;e in tlw

t'Xcretiun of thi,: nuclen~ick c·ou ltl lw oh:<c·n·t·d af'ter ;,tarling lhe irradiation

therapy in all thn·c· pali(·nB, wlw;.. C' urinP wa,., analy zc•tl.

.1 "''- l st. .S" l"' r. /irndtù (l!l 7lt) 6, ~ 6 Gt.

S HEJBAL 55

TAOLE 5.

Specific nctivities of dCMP-and C(lR-aminohydroJases in tissues of mammals and chick emhryos of varying age.

.\11 vulues for m!unmulian tissues were obtnine<l by the microbiologicul deterrnination of the deamination produrts, dlniP und UdR rcspectively, after l·olumn arul paper ebro· mutogra)>hy of reaction mixtures. Values of tbe chick cmbryo dcoxynucleotide anùnohy­tlrulase wrre obtained by tbc spectrophotometric method. The specific activities are repor­trd in lll!J. tnoles deamination product forrned per l hou.r and l mg protein.

- - - -- -- -- - -Spfci6c artivhitl

N'.unber

'ri•&ue o t'

Spe ci es dCJIII' ominobydrolo.., CdR-tuninoh)drolue An•J yz.ed ti•tuet

r mKe l me a o. runge l mean

l l l l Ha t li\ rr 1. 5-3.5 2.6 < 0.5*-1. :1 0.9 ll

spleen l l. 9 -.J.l 3 .7 0.9- 2 .2 1. 3 7

leukocytes 2.0- 3.2 2. 8 l. 2- 2.3 1.7 6

musei e < O.S - < 0.5 - 3

Cattle liver l < 0.5 - < 0.5 - \

spleen < 0.5- 1.5 0.9 < 0.5 - 4

Calf liver 1.2- 2.4 1.6 < 0.5-1.6 1.2 6 spicco l 2.3- 2 .9 2.5 ......... 0.5 - 6

thyruus l 3.5-4 .5 \. 3 2.0-2.8 2.6 \

l.hick embryo • l 5th day 6570- 5200 5830 - - 6

l 7th day l 3 100- 1850 2500 - - 8

lOth day 2050-1100 1350 - - 6 l -'

(• ) Tbc \ alue or 0 ,40 wu Uted lcr ealeulations of lbfl mean.

Discussion and Conclusions

Thc present results confirm the previous report indicating tbat the urinary cxcretion of CdR in man is very low as compared with other spe­cies. especially the rat. In the latter species the excretion of CuR is a rela­lively good indicator of early irrauiation damage.

DRAUOVSKY, WIN'KLt-: a · ·& SKODA (1964) anu Gunr & Cot.E (1968) sug­gcsted that in the rat the spleen may be the main source of excess CdR Pxcreted following irradiation. Rccendy this was proved by elegant r xpe­riments of GERBEU & R EMY-DEFRAIGN'E (1969). Thcsc authors concludetl lhat ull excct.s CdR excreted in rats and mice after irradiation can originate from tlt!stroycd cells, <:!!pccialiy lymphoid tissue, although a ccrtain contribution to tbc r xcrction by nonutilized precursors ca nnot be Pxcludcd.

l nn. Cst. SII!JO'f. 8anilli (1071l) 6, 16- 61.

l

l

l

l

l

l

l

l

l

l

l

l

l

l

l

l

l

l

l

l

l

l

:l(, ,..._ .. , ICI~' Il ~ HU t-ICi Ili

.= <.. ... - ... :-: ~· - - - - - - - - >:"l -·;: - - -"' -; ~

., .. :l: .:: .:: :.

j -= :: :. :: :: = = :: :: = :: ::. ::

e-1 ::: ::. :. :: :: ::. ::: :: t:J.. = :: = ::: :: = ::: ::. = :-: ...

" ~ ~

c ~-= ' -

<l --· ,,., ,., = . '" l. C'l l;: 0: :. ::. o# ,.,

"' c '" "' ;-. <"> ,~

<1. ; l ,l ;: ::: ~ "' 0: O" ,., - ,., c = •t: .~

o ""' ·- ;::, -.c ,., ,., ..:; ::: cc ... Cl:

..- Cl

c ., c ... ... Q c.o t ..::

"C

Q:; e-1

"C t:J.. ... .. ; (.;; :J. .. ; . ... " ;.. c: ; c: ..... ;: ,. ~ -: ~

:: -o ~ c: ~ e 1:: -.:: .. ~ t ~ "C e ... ~ .=. ..; -= ..::: ..:: ..:::. ;>. -; ..:::. -; rs. " - l: = '" " l -- Cl: Cl ,,.,

"" ...... C"l ;> :. -.. -·;; Q:; c "C c.o ~ "' <.l "'C ... ~ c ; <:

~ ,.... ~ C'l . -.::

~ -5 .... c:: ::::: Q C'l ;;. ~ ~ E .... ;:. ....

c: <: " c e J. '-

" i; J: -00 c.o

-= :: !.. J: '-'

c .: e "' l

== .f ....

·c ... ;: " >. ..

~ e e '-e - ... '-<..

"'C ' ;:. ,., ... '- ..:::. ..:::. g o ~ .:::

~ <: ... ;; c ..:::.

. : ..:::. ..:::. <. ... !:: ,-... Col - l = l l ~ = <.. ._;. - '-

...... ... ~

l C'l . o Q e 3 '"' ""' -

:E ,.,.., """'

t., .. l•t. ~11/11'(, ,...,(llltlll (I!J;UJ 6, 4to fol.

'IH&.IBAL 57

lf human metaholism of cytosine components of DNA were similar to that in rats, much highcr urinary excret ion as compared to expcrimen­tal values would be expected as well in normal individuals (approx. 40 mg/ day, against only 10 [Lg/day found) , as in irradiated suhjccts.

The rcasons for tbc diffcrences in CdR cxcretion in differrnt species eoulù possibly be due to essential differences in tbc metaholic patbways of cytosinc derivatives. The deaminases of dCMP and CdR may play an important rolc.

Dcamination of dCMP by human livcr homogenates was first described by CAl\HENER (1967). He suggested that tbis occurrt>d by catalysis of the !>ame eozyme responsihle for the deaminatioo of CdR, CR and their dcriva­lives (a non!ìpeci{ic nucleoside aminohydrolase) after dephosphorylation of the nuclcotide by phosphatascs. In the present invcstigation, in which the nuclcotide deamination was 8tudied in condit ions whf'rr the cnzymatic dcphosphorylation to the nucJeosidc was Jnade impossiblc by addition of NaF, evidcnce was obtained (by tbc det ection of the deamination product dUMP, temperature inactivation and pH-optimum s tudics) that two dif­fcrent aminohydrolases are responsihle for tbc deamination of the respectivc nucJeotide und nucleoside. This is in accordanee witb the known pt·cstmce of dC.MP-aminohydrolase in actively proliferating human tissues: in tumours (MALEY & MALEY, 1959; TALARICO et al., 1960), in tbc stomuch, ilcum, colon, l:>igmoid colon and rectum (GUERRITORE, RocCBI & SETZU, 1960), in em­bryonic livcr (TALARJCO, DANESlO & SCARA.N'O, 1961; ScARANO, BoNADUCE & DE P ETROCELLIS, 1962), in tumours of the female gcnital t ract (MANCON'l et al. , 1964a), in placenta (MA GONI et al., 1964b) and in hone marrow (SHEJ­BAL, KosTIR & SMtD, 1968).

[t can be spccnlatcd tbat the prescnce of highly active dCMP-amino­hy drolase in slowly proliferating tissues as livcr and spJeen (SnEJDAL, KOSTIH & s~uo, 1968) and in nonprolifcrating leukocytcs (StLBER, GABRIO & H uEN­"'l'EK'ENS, 1963) indicates that this t>nzyme is not, at least in t hcse tissue8, a limiting factor of tby midy late synthesis. Trus is in contrast to f indings in many other specif's, espccially lhe rat. Emhryonic rat tissue (MALEY & ,\1ALEY, 1959) aud regeneratiog Jivt>r {)1At.EY & l\f.HEY, 1960) rcvcal high activitics of this (•uzyme, wbile i11 normul adult rat Hvcr activities are vcry low (i\fALEY &, M.At.EY, L961).

Activc human CdR-aminohyùrolasc was found in tbc scrum und unlo­calizcd tissues by Kmss et al., (1963): in intestine (CREASEY, 1963), Jiwr ki­dney and heart (CAMLENER & S;\UTn, 1965), leukocyt('S (Sn.AER, 1967), -.plcen and bone marrow (SREJBAL, KosTtR & ·ano, 1968). In tbis invt>sti­gation it was shown that .intact lcukocy tes in suspension are c·apable of metabolising CdH. This finding inilicatrs that evcn if Cd R lilwrated into perifcrul blood wt're not mctaboliscd in thc livcr or f. pleen , it ('an be d('ami-

l •m. fai . ,).,pe r. '""ila ( tu7fl) 6. ~() 61.

l l l l l l l l l l l l l l l l l l l l l l l l l l l l l

nat•·d h~ irt·•·h t'Ìrl'ulatin:.: lt·ul..nn t• ·~ . lh ''"lrapolatÌrt;! fnorn tlw in I'Ì i ro

CP"ltdh. i t i• t'>1 Ìlll<tll•d tlwt lo·ukul'~ ,, • .., of t Ili' Jll'ril'nal ltlowl ol an adult

man an· t•apahl•· uf do·mn inaLÌII !! a~ nnwh a ;. 2;) rn g (.ciH pPr hour .

l 11 ordo·r lo 'erif\ "lwtbPr tlw dt•aflrination prudu<'f , uf CtiH a1ul ."i-~J,.

-CdH. dt·n~\uridirw and thyrni rl ino·. an· ''"'r!'lt•d in :<uh:-:tantial anwunf ,

}l\ illllllttll ,... a 11umlwr of anuh,.i-. nf urrr11· ,..arriplt·~. lwfmT arrd after

irradiatitm. '"'rt' rarri•·d nul. lt ,,a ... fouud that il' l lciH uncl TdH ar•

t'"f'l'f'lt•d . tJH ''\- Hff' )'ff '" l'lll Ìll JnliiiUil llrÌIII' Ì!l tltWIIIIth fm\l'f than ]0 !1.1-(

21 hour,.. tlw ]mH·:< t amount d••tt•t• t aLI•· Il\ tho• nwthud appli•·•l. H•·""''" nl an al~,..; ... nf !'if' \"l'ral po,..tirratliatinn uri n l'' \l'f' rt' <~l"o tlt'gati' t· . TL ... a;.~ tlllr•·d

p o :- t irrad i:ttiun hr•·akdown ;,. prohabl~· ""' r• ·O•·t·t r•d ), ~ la q.:•· TdH , .. ,.rrf't in n

lwt·au,..t· n f t•tff•rtÌ\ t ' furtbt·r t'<llalwli-.rn of thi- t'<Hnpound iu Jllan. l t ; ... l..uown

that urirtaT) ''"<' rt'IÌnlt of f~·arninni ... ohntyrit· arid. tht· t·a talwlitc- of TdiL ;,., int•rea..,t·d aft t· r irradiatiuu ( (,EHHJ:.R l'l u/.. l9CIJ: (;ERIIEH 1•1 al .. Jl)(,~~ ).

Tlw impo..,,.,j),ilit~ of tlt•nwn;.trating a largt· inrrt·a;.•· in tLe po~ Lirrarliatiou

I'Xt'rPtion ol' lldH. tlw csrt aholitf' nf' \.ti IL indiPalP,;. by aualo~~ "ith TdH. Lhat furtlwr rapicl c·ataholism oertrr:- (probably ,·ia urac·iL clihy druuraeil.

r~-ureidopropion.it· a c iti . ~-alliÌIHl )'T<IJIÌOnamicl !' to r~· ahuaino·, Fr N't.. f'l Ili. , 19.)()).

lu far t w ith a lar~·· t'xt'el>,., of hum au Jj, t•r ht~rnogi'Uatc· in t be n· a<" l ion mi."­

tun·, u:wd l'or CdH d!·amination , tudi··-. furmation (l(' ural'il was ob;.••rn·d

(unpublis lretl). 1f th• ~ indic:atccl pat hway i~ real. i t cannot Jw t·xcludc•d tha t

t'onte · furtbl'r ca taholitc· of UdTI (uraril. dih ydrouracil, (j-urC'idupropimtit·

a c icl. ~-alanirw) might, in man , !Jt' fuuml Lo n•f'lect postirradiation ])1\ A

bn•akdo\1 IL. So far prdimirtar~ ,..tudie~ of cbangc· ;.. in po~tirradiation urinar~

c•xt'rl'tiun of ~j-alaninl' ga' •· nq.!ali' c· n ·-.ult-. . OrJ~ loeall~ irradiatc·d t•arwc•r

patic·nt " wt•r•· ;.tudic·d (unpubl is lwd ).

Higlr at'lÌ\Ìtit·s of dCMP-aminohytlrola,...· in tlw ;. tudic·tl humart ti ... , uc·,..

Ula ) <'3111>1' dl'alllÌitatÌOiì of l' )'tO;..Ìnc· ('UillJHHlii(J;., at thl' ttUdi'Otidc• ]t'Vt'J wl.wn

tbc·;w, a • prt· ~ttnwd , arf' li h era tr>cl b: pns tirradia t io n dcgnulat iort of D A.

Ont· ca n t' Il\ i ~agc· tbc· following ca t aboli l' patb,, a)"' to bP prt ·:o;ent in rnan:

!--- Dl\:\ ----

5MI·tlCMl'- ··dDlP Il Ll ~IP dCM.P

• SMcCdH - ·TciH hlH· - CJH

T u

• BAlBA ~-ahtnù1c

l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l

-

..,llt:JB\1.

:-;o far litth' is kr\O\\ n about lhe phoi<phala:-.~· a<:li' ilies rn human tis­

;.ut•;.. FI HA et al., ( 1962) tle•:-crib.-<1 a n:ciproeal rda l iunship bct\\ Cen dC~1 P

am inuhydrola:st> activities aml ci C:VlP -phos phala;;e• <H'l ivities in rat ti,..sueR

of tlill'cr<'nt prolifnating a <•tivi t y . lf thcir lindings :<ho uld apply gmcrally a lso W olhcr tissues an.<l s pecie:>, thr dramination of cytosin.e compoue>nts

l'rom D --"'A may, ir\ m ar t, occur mainly a t t.lw nudt•o t id<· lc·vd . But <'VPn

if th<' mair1c·ataholic pa th way wt·re DN.\. ~ dC\1P-~ Cci l{ aud tlw nw·l t•o,ide•

\H'C\' libt•ratrd into pt•r ife·ral blond, t h<' t l<'aminalin~ capacity of l<·ukoe~ tt•s almtt' i,.; :-o high thal iL \\<wld, probably, h<' t•apabl<· nf cle·alin~ ''ith all ,,.._,., .... ,..

Cd l{ libt>ratt·d al lra:~t up to a ePrtain do:w, (t'"JH'I' ially in ea,c·, of loea l irra­

dialion "ht·n circulati ng 1Ptd"oC)' tes a re r10t primarily Pli'!·ctetl). Cdl{-arni­rwh ydrola~e [rom hn rnan liYPr \\US found to lw r..JatiH·ly resi:ste·nt tn irra­

diation in vitro ( unpubli, bcd). [ t thus uppt'ars 1 ha t high Cd H-uminohydro­

la:·w adiviti«>s in huma n liY Pr (ZTCHA & Ru n rc, l 1)(>1)) rnay rwt be tlw ouly and main rt'a"Oil l'or 1lw a hst·nc•~ of a mas,; iv1· posl irradiatiorl urinary t•xc·rc•­

tima of Cc.ll{ in man. Tlw n•;;ult s of BERHY l'L al., ( I<J() :~), al·nmling Lo "hida

hi~h UIUOtmts o r Cd i{ (in the· r<utge \daich may hc• l'X(H't'lt'(' jf d<'amirlation of ('cii{ \HHrld not O!'c·ur) \\t'n' founù to be· t'\.l'rt'lo•d uftc·r "hole-bod) irra­

diatwn of t'' n p.lti!•nt;o,, '' hil~ rw CdR could IH' dt'lt't' tt•ll IH'forP irratliation,

po;.,.ibl~ re pn•spnt ca,..('s in ' ' h.il'h the a!llount uf (:d H librratc·d in a ~hort litllt' P'H'I·nlt"cl thc d1•mninating eapacity in tlw hlootl Ilo" ·'}"tit!·m Lwfor.­ro•at·hing the killn.-y. Abo llw l'a,;e of tlw ,,holc·-bod y irratliatt·!l patit't\LS

n·ported by AntENT, Dn:NSTIHE lt & S n E.JB AL (19M>) (di,.,~;ussed iu th1• intro­d uc tion) rnay rc•p c·e~>c•nt a ease in which , al least tc•mporarily, t he ovNall Ccll{ cleaminating capacit y was not high t•n c1ugh to deal with PXC:t'iìS

Cd H. rd<·asc·d irtlo p<'rife•ral hlood (d uring tlw fi.rst :} hours of the lirst day

aft c·r irradiation). This "a~ howt•ve·r compli('atNI hy l hP fa <'l that ulrcady prl' ir­radiation umounls of Cd R <'Xt' retcd w(•re un!'llllllnon l high, pos,.,ibly c lui'

to l!l\\t'r aminoh~clrola,e al'li,iti«>,.; as n·por t1•d by StLOER (1967) in ease•,; of

.u·utt- rnydotic IPnknrria. l t is t•vidPnt fmrn tlw diifc·n:nce in cytositlt' nudl'u~ide' and nudc!cHidc

arninohydrolase activitie•s that cl iffprcnces in CIIH a•xc rTLion observc·d in.

di fl'l' rt' rtt species art' probably dun to this :; l<'p irt t lte l'alaboli;;m of rytosi rH~ l'lllllJIOIII'IltS uf l) ~,\. Soni!' o l' thf' slri kin g dilfc· rt·nc:c·s in dC MP an d Cd H

rr at·taholi~<rn irt 1lw ral ami man have lwen rl'lwrte•d lwl'ure by Kut:-.s Pt 11/.

! l%:q, C\\IIE"'EII & S\111'11 ( 1%;')) und ZICHA &. !ltRIC (l%9) althouuh il -lwuld bt• mPrttiOtwd t ha t urtly appart>nt Cll7.) urali t• ;w li\ ities we·n· ,..tu dic·d

Hl tlw homo~t·nalt''· Fr, 1.' l\ FI '"-' ( 19(1.3) . huwPcl l h al an c·nzpualic inhi­IJilor <'art bi' n•.;pon..:ihlt· fòr lo" apparcnl ··~ lo,irw rttll'lt·utidP amino h~ dro­

la~•· arti,·itit•,.; in ;.ome• ti:-:-aw>-. The l'n·,wnl \HJrk indii'Ult':< tlaat high dC M P-and Cd B-aminola ydrula»t'

.tt' I.Ì.\. i l if•,.: in h m n an t i'<;.tws an d f':<lweialJ y i rt hloud rna y h e tlw c·au,.;c• fur

litt l ..,l't- Hlfo '/t l Hl( EIH tU

tLc• ]m, Cd H 1' :\.!'rt' lÌon m Jllélll . T h i~ sc•c·m~ also to IH· LIH' rt·a~on l'or t lw alo­

~«' 111'1' of laq.!'' pos tirradiatio11 <· hall ;!«'~ in il~ «' \.C' t'l' l io11.

Tlu• autl.nr "i,Ju•• lo thuul.. l'rof. H l\l>r . . 1. "O'lir. lfead of tlot· llt·par lnlf' otl nf ll io­

('ht•rui~tr). Claurle:-- L1nj\'Pr:-:i t ~ in Pra~tut• fu r enabliug JHu ... t nf 1 ht· ~·or~ 1o l w c·:trried 011 1

111 )o j,. lrhlrlult· aud R"'l>r. l•. S ru id frour thc• lrl'ti tu tt• ufl'utholuJ!~ - Clonrlt·• l ui\f'r•it' Pnt~UP, for prof'u nn;,! nut:-l uj thc luuuau Li ..... u..-... ~tudir-cl

Tlw arrtlror i• J!ratcful lo Prof. J>r. ~1. Quirrtiliani frnru thr 1-titutu ~rrpc•riorr eli Sanit.L

HutlH'. for eu:rlrlortl! tlw couc·lu•ruu of tir i• worl. aucl for tl11· rt'\ i•iuro ul tltt m.uru·•·npt

Thr- wnrl. "''" aidt>d in pari ],~ u ,.:raul uf thc> Czt:>c·hn-lo\'al. \lirr i-tn uf l ·.clru·atrurr

Uc ull'ld Aprii l:l. l9iU.

Act'<'f11Nl .l ur ot· l 6. 19iU.

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