blood 1972 van der weyden 23 30

8/14/2019 Blood 1972 Van Der Weyden 23 30

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1972 40: 23-30

Martin B. Van Der Weyden, Mary Rother and Barry G. Firkin in Folate Deficiency12The Metabolic Significance of Reduced Serum B

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2/9

T h e M etab o lic S ig n ific an ce o f R ed u ced S eru m B1 2

Blood , V o l. 40 , N o . 1 (Ju ly ), 1 9 7 2 23

in F o la te D e fic ien cyB y M a rtin B . V a n D e r W e yd e n , M a ry R o th e r, a n d B a rry G . F irk in

T h e d e p re s se d s e ru m B1 2 le ve ls a c-co m p a n y in g fo la te d e fic ie n cy g e n e r-a lly in c re a se fo llo w in g fo lic a c id th e r-a p y , a n d th is p h e n o m e n o n is c ite d a sevidence that true B1 2 d e fic ie n cy d idn o t p re e x is t in s u ch in s ta n ce s . In th iss tu d y , th e m e ta b o lic s ig n ifica n c e o fre d u ce d s eru m B1 2 le ve ls c om p lic atin gfo la te d e fic ie nc y w a s d ete rm in e d inb o n e m a rro w cu ltu re s b y e va lu a tio n o fa b n o rm a l inc o rp o ra tio n of d e o xy u ri-d in e in to D N A -th ym in e, a d e fe c t ch a r-a c te r is tic o f m e g a lo b la s tic m a tu ra tio nd u e to fo la te o r B1 2 d e fic ie nc y . In inv itro m a rro w cu ltu re s o f se ve n p a tie n tsw ith fo la te d e fic ie n cy a nd n o rm a ls e ru m B1 2 le ve ls , a d d e d 81 2 resu l tedin n o ch a n g e in th e d e p re sse d in co r-p o ra tio n o f de o x yu r id in e in to D N A -th ym in e , w ith co m p le te c o rre c tio n o fth e d e fec t b y ad d e d fo la te , H o w e v e r,in m a rro w cu ltu re s o f five p atie n ts w ithfo la te d e fic ie n cy a n d d e p re sse d s e ru mB1 2 le ve ls , a d d e d B1 2 produced a par-tia l co rre c tio n of th e d e fe c tive d e o xy -u rid in e in co rpo ra tio n , w ith co m p le te

co rre c tio n b y a dd e d fo la te . In v iv {2 4 3 }p h a rm a c o lo g ic d o se s o f B1 2 in a p a -tie n t w ith fo la te d e fic ie n cy , b u t n o rm a ls e ru m B1 2 le v e ls , re s u lte d in n o a lte ra -tio n in th e d e g re e o f m o rp h o lo g icm e g a lo b la s tic m a tu ra tio n o r th e a b -n o rm a l d e o xyu r id in e in c o rp o ra tio n in toD N A -th ym in e. In c o n tra s t, in a p a tie n tw ith b o th B1 2 and folate deficiency,B1 2 th e ra p y re su lte d in p a rtia l co rre c-t ion of the a b n o rm a l d e o x yu r id in e in -co rp o ra tio n in to D N A -th ym in e . w iths im u lta n e o u s re d u c tio n in th e d e g re eo f m o rp h o lo g ic m e g a lo b la s tic m a tu ra -tio n . H o w e ve r, a b n o rm a l d e o xy u rid in einc o rp o ra tio n in to th ym in e -D N A , c o n -s e q u e n t to fo la te d e fic ie n c y , p e rs is te d .S im ila r fin d in g s w e re o b ta in e d in ap a tie n t w ith fo la te d e fic ie n c y a n d a s so -c ia te d re d u ce d se ru m B 1 2 . It is sug-g e s te d th a t th e d e p re sse d se ru m 81 2in p a tie n ts w ith fo la te d e fic ie n cy re p re -s e n ts a tru e d e fic ie n c y fo r h e m o p o ie tictiss u e a n d co n trib u te s to th e m e g a lo -blastic m a tu ra tio n b y its e ffec t onf o la t e m e ta b ol i sm .

C O -E X IS T E N T , R E D U C E D S E R U M B1 2 lev els be low the n orm a l ran geoccu r in ap pro x im a te ly 40-60 o f p atien ts w ith m ega lob la stic an em iaco nsequen t to fo late d eficien cy .3 A ltho ugh tru ly independ en t B1 2 leve ls fo l-can no t b e en tirely ex clu ded , th e spon taneous inc rea se in serum B1 2 leve ls fo l-low ing fo la te the rapy 7 is c ited as ev iden ce tha t tru e B1 2 d efic ien cy does no tex ist un de r these c ircu m stances.4 S ugg ested m ech an ism s re spo nsib le fo r thep rod uc tion of dep res sed se ru m B1 2 leve ls inc lud e m a labso rp tio n of B1258 or

F ro m th e M on ash U n iver sity D e pa rtm en t o f M ed ic in e , A l fred H os p ita l, M elbou rne ,V ic to r ia , A u stra lia .

Sub m itted D e cem be r 2 8 , 197 1; rev ised F ebr uar y 10 , 1 9 7 2 ; acc ep ted F eb ru ary 1 0 , 1972 .Sup po rted by T he A n ti -C a nc er C o un cil o f V ic to ria , T he N a t ion a l H e a lth and M ed ica l

R es ear ch C ou nci l, E . H . F la ck an d 7 . R . G . a nd E. M cK en zie Sch o la rsh ips , A lfre d H osp ita l ,M elbo ur ne , V ic to r ia , A u stra lia .

M artin B . V an D e r W eyd en , M .B ., M.R .A .C .P . : R ese arc h F e llo w , M ona sh U niver sityD epa rtm en t o f M ed ic ine , A l fred H os p ita l, M e lbo urn e , V ic to r ia , A u stra lia . M ary R other,B A .:R e sea rch A ss oc ia te , M ona sh U n ive rsi ty D epa rtm en t o f M ed ic in e , A lfr ed H os p ita l,M elbou rn e , V ic to ria , A u str a lia . B arry C . F irk in , M .B ., F .R .A .C .P .: P ro fes sor o f M ed ic in e ,M on ash U n iver sity D ep artm en t o f M ed ic ine , A lfre d H osp ita l, M elb our ne , V ic to ria ,Austral ia


3/9

2 4 V A N D E R W E Y D E N , R O T H E R , A N D F IR K IN

5 m.Sh VIT HF

12

TH F- F ig . 1 . S yn th e s is o f

D E O X V U R I D I N E - { 176 } UM P D N A -th y m in e fro m d e o x-I D H F rd uc ta .s n ho hL vo lve m e n t o f v ita m in 81 2I a n d fo la te in te rm ed ia te s

ThYMIDINE - dTMP are indicated. dTMP, thy-DH F m id in e m on o ph o s p h a te ;

T HE , t et ra hy dr of ol ic a ci d;T h V W 1 DN A DHF, dihydrofolic acid.

red istrib u tion of B1 2 w ith in the bod y .7 8 Z alu sky e t a l.2 4 rep orted tha t, inpa tien ts w ith u ncom p lica ted fo la te de ficien cy , pha rm aco log ic doses o f B1 2 w erecapab le o f indu cin g a re ticu locy te re spon se , d esp ite little change in the d egreo f m orph o log ic m ega lob las tic m atu ra tion . T he m e tab o lic consequ ences , how -eve r , o f reduced se rum B1 2 leve ls in fo la te -d efic ien t sta tes a t the ce llu la r leve l,o r the co n trib u tion of dep re ssed leve ls to m eg a lob la stic m a tu ra tion , rem a inspecu lat ive.

A sens itiv e in d ica to r o f fo late o r B1 2 d efic ien cy at the ce llu la r leve l is thein terfe ren ce w ith effec tive D N A -thy m ine sy n thesis from d eoxy urid ine (d U ) insho rt- term in v itro h um an bo ne m arrow cu ltu re s . In n orm ob la stic sh o rt-te rm cu ltu re s , ad ded dU en te rs the deoxy urid ine m on oph osp ha te (d U M P ) -thy m idm ne m ono pho spha te (dT M P ) -> D N A - t h y m i n e pa thw ay an d sup pre sse sthe inco rpo ra tion of subseq uen tly add ed tr itiated thym id ine (3H -T D R ) in toD N A . {1 76 } T he in te rre la ted b iochem ica l p a thw ay s are sho w n in F ig . 1 . In te r-fe ren ce w ith th e dU su ppressive effec t is ab norm a l and is a re f lec tion o fred uced tissue fo la te leve ls .0

T h is p ape r reports stud ies o f ab no rm a litie s o f syn thesis o f dT M P from d Uin in v itro bo ne m arrow cu ltu re s from p a tien ts w ith fo la te de fic iency ex h ib itin gassoc ia ted no rm a l o r redu ced se rum B1 2 leve ls , an d the e ffec t o f pha rm aco log icdoses o f B1 2 in v ivo in m od ify in g the abno rm a l dU sup press ive e ffect in fo la tede fid en cy asso c iated w ith norm a l se rum B1 2 leve ls o r th ose be low the n orm a lrange.

M A T E R IA L S A N D M E T H O D SE ffective syn the sis o f d T M P from d U in h um an m arrow w as m ea sure d by the a b il ity

of preinc ub atio n w ith un labe led d U to su ppress in corporatio n in to D N A of su bse qu en tlyadded 3H -T D R , as desc rib ed prev ious ly .1 011 In th is sy stem , abnorm al syn thesis in m eg-alo b la stic a ne m ia is de m o nstrab le b y red uce d a b ili ty of p rein cu bat ion w ith d U fo r 1 h rat ro om te m p era tu re to su pp ress inco rpo rat ion o f sub seq uen tly ad de d 3H -T D R . F or bo nem a rro w cu ltu re , 1 5-2 0 m l o f m arrow w e re asp ira ted d ire ctly in to 10 m l o f co ld H a nkssol ut io n co nt ain in g he pa ri n, 10 0 U/mI. All operations were carried out as previouslyde scribed .11 T h e rad ioac tive p rec ursor used w as thym id ine (m ethy l-3H , spe cif ic ac tiv ity26 C i/m M , R adioch em ica l C e nter , A m ersha m , E ng land ) p rep ared as a so lu tio n co nta in ing10 C i/m l. T h e d U load w as 10 m ole /m l, co ncen tration of added B1 2 (cyanocobalamin)1 pg/mi and foii c acid (P C A ) 5 0 pg /m l. M a rro w cu ltu res w ere p erform ed in tr ip l icate ,


4/9

R E D U C E D B 1 2 IN F O L A T E D E F IC IE N C Y 2 5

an d dU , fo lic a cid , o r B 12 w a s ad ded to e ach set of c u ltu re s. 3H -T D R in cub ation (1 C i/m l)w as pe rfo rm e d at 37 {1 76 }C for 2 hr , and D N A w as ex tracted f rom th e pre cip i ta te b y th etec hn ique o f F e ine nd ege n e t al.12 as m o dified by C o ope r an d R u bin .3 T he ra d io act iv ityof the D N A e xtra ct w a s m easure d in a liq u id scin tilla tio n cou nte r (N uc lear C h ica go C orp .,D es P lain es, Il l.), an d resu lts w e re exp res sed as to ta l ra d io act iv ity inco rpo rated in to D N A .A t th e tim e of asp ira tio n of b one m arrow sam ple s, v eno us b loo d w as assaye d for se rumB 1 214 an d fo late .15 T he n orm al ran ge o f se rum B 12 is 2 00 -80 0 p g/m i a nd th at of se rumfo late is 3 .2 -2 0 .0 ng /m l.

T he pa tien ts s tud ied con sis ted of sev en pa tien ts (N o. 1-7 ) w ith m e galob lastic m aturat iona sso cia ted w ith red uce d serum fo late below th e n orm al rang e b ut n orm al se rum B 1 2 lev els,a nd fiv e pat ien ts w ith fo late de fic ienc y an d a sso cia ted re duc ed seru m B 1 2 lev els be lowth e n orm al ran ge . T h e lat ter gro up of pa tie n ts (N o. 8-1 2) e xh ib ited no rm al re spo nse ing astric sec retion to pen tag astrin 16 o r tub eles s g astric a na lysis, a nd w ere neg ative fo rg astric p arie ta l an tibo dy .18 T he cl in ic al d eta ils a re sho w n in T able 1 . In the pa tien ts w ithn u tr itio nal m e ga lob last ic a ne m ia , th e d iet w a s ev alu ated by the ho sp ita l d ie titia n an d o neo f the au th ors and w as c on sid ered inad equ ate to m ain tain fo late sto re s, bu t w as notd efic ien t in B1 2 .

R E S U L T SIn no rm ob la stic m arrow cu ltu re s , ad ded dU en ters th e d U M P - d T M P

D N A -thym ine pa thw ay , so th at the in co rp ora tio n of sub seq uen tly ad ded 3H -T D R in to D N A is reduced to 10 % o r le ss o f th e con tro l m arro w cu ltu re s , i.e .,cu ltu re s no t p re incub ated w ith d U . {1 76} T he abn orm a l dU supp re ssio n of 3H -T D R incorpora tion in to D N A in m arrow cu ltu re s ob tain ed from pa tien ts w ithfo la te de fic iency is sho w n in F ig . 2. In pa tien ts w ith fo la te d efic ien cy b u tn o rm a l serum B1 2 lev e ls (N o . 1-7) , Fig . 2A show s th a t the add ition of B1 2 tothe m arrow cu ltu re s re su lted in n o sig n ifican t co rrec tion o f th e d efectiv e dUsup press ion , w ith com ple te co rrectio n (le ss than 10 % ) b y the ad d ition o f fo licacid . In co n tras t, th e ad d ition of v itam in B1 2 to th e m arrow cu ltu re s ob tain edfro m pa tien ts w ith fo la te de ficiency and reduced se rum B1 2 lev e ls be low th eno rm al ran ge (N o . 8-12) produ ced a pa rtial co rrectio n of th e m etabo lic d e fec t,w ith co m ple te co rrec tion b y the add ition o f fo lic ac id (F ig . 2B ). T he tw o g rou pso f pa tien ts w ith o r w ith ou t red uced serum B1 2 leve ls be low the norm a l ran gem ay n o t be s tric tly co m parab le. T he pa tien ts w ith redu ced B1 2 leve ls (N o . 8 -12 ) in clu ded four pa tien ts w ith n u tr itiona l anem ia an d a p atien t w ith ep ilepsy(on D ilan tin the rapy ). In th is g rou p o f pa tien ts , the degree o f abn orm a l d Usup press ion w as pa rticu la r ly u n ifo rm (see T ab le 1 ) . T h e g ro up of pa tien tsw ith n orm a l serum B1 2 lev els (N o . 1 -7 ) w ere le ss un ifo rm in clin ical s ta tu s,inc lud ing th ree pa tien ts w ith a lco ho lic liv er d isease . T he degree o f abn orm a ldU su ppression w as sim ila rly le ss un ifo rm , va ry ing from 18 to 77 % , andserum B1 2 leve ls ran ged from nea r the lo w er ran ge of norm a l to abov e th enorm a l range (T ab le 1 ) . T he un ifo rm , in v itro re spo nse to B1 2 in m arro w cu l-tu res in the tw o g ro ups o f pa tien ts m akes it u n like ly th a t the d iffe rence inexpe rim en ta l o bse rv atio n b etw een the tw o g ro ups w as d ue to fac to r(s) o the rthan th e d ifference in B1 2 levels .

T he e ffec t o f pha rm aco log ic doses o f B1 2 in am elio ra ting m ega lob lasticm a tu ra tion due to fo la te d efic ien cy w as stud ied in one pa tien t (N o . 3 )-w ithredu ced fo la te be low the n orm a l ran ge b u t n o rm a l se rum B 12 -w ho , d u ringthe stu dy , w as adm itted to a g en e ra l w ard bu t m a in tain ed on a d ie t s im ila r to


5/9

26 VA N D E R W E YD E N , R O T H E R , A N D F IR K IN

C0 Z +4

-0 - N . - SJ0 O) C) 1 0 1 - C ) 1 0 04 C D C ) C )C1 )

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U ) 00 0w 0 )0 )0 0 0 0 0 0= 0 .0 0 0 .() .0 .0o 2 0 0 0 0 0 E E o o 00 0o 0 00 00 > . ) . {17 6} 000o 0 ) 0 )0 )0 )0 ) - 0 )0 ) 0 )0 )0 )0 0 0 0 0 0 0 0 0 0.2Co 0

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G) 0 0 00 0C C C C C (4 )0 0 - 0 0 .2 {176} .0 0 .O c 0 0 0 E .00U ) 0C (0(l ) -C l)c cO o o o ..O cC l 0 )(0 - -0 0--0O- 0.0 .0 . 0 , >, .0 .0 -- .0 - 8E

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6/9

R E D U C E D B 1 2 IN F O L A T E D E F IC IE N C Y 27

D U A LO NE {149}2 l( ;A lX A L O N E + B, 2 { 1 4 9 }G A A IIQ

oo8 o7o

42O : .

( 10pO 1

___________ __ ___ ___ ___ __ ___ ___ ___ _ p o o l { 1 4 9 }40 1

F ig . 2 . E ffe c t o f fo lic a c id a n d v ita m in B1 2 o n d U s u p p re ss io n o f 3 H -T D Rin co rp o ra tio n in to D N A in m a rro w cu ltu re s fro m p a tie n ts w ith fo la te d e fic ie n cya n d n o rm a l se ru m B1 2 le ve ls (F ig . 2 A ), a n d w ith fo la te d e fic ie n c y a n d re d u ce ds e ru m B1 2 lev e ls (F ig . 2 B ). D e o x yu r id in e (d U ), 1 0 m o Ie ; 3 H -T D R , H 3 -th ym id in e ;fo lic a c id , 5 0 g /c u Itu re ; a n d B1 2 , 1 z g /cu ltu re . M e a n in d ica te d b y h oriz o n ta lb a rs .p reho sp ita liza tion . D uring a co n tro l pe riod of 3 d ay s, the re ticu locy te cou n tranged from 0 .3 to 0 .4 % . S erum iron w as 2 00 1tL g /10 0 m l to ta l iron b ind in g

cap ac ity (T .I .B .C .) 2 70 /L g /10 0 m l, se ru m fo la te 1 .4 n g /m l an d B1 2 260 p g /m l.T h e m arro w m o rp ho lo gy w as frank ly m ega lob la stic , and dU su ppression of3H -T D R in to D N A w as 77 % (n o rm a l le ss th an 1 0% ), w ith n o e ffec t b y thead d ition of B1 2 to the m arrow cu ltu re s an d com ple te co rrec tion by th e ad d itiono f fo la te . S ubseq uen tly , B1 2 (cyano co ba lam in ) w as adm in iste red i.m ., 50 0 zg /d ay d uring an 8 -d ay pe rio d . R epea t m arro w b iopsy at the com p letio n o f B1 2th erapy exh ib ited n o change in the m orpho log ic d egree o f m eg alo b la stic m a tu -ra tion , and the dU supp ressio n w as u nchang ed at 7 9% . R eticu locy te co un td u rin g th e B1 2 ad m in istra tion ran ged fro m 0 .2 to 0 . 5 % . O th er p aram e ters a tthe tim e of repea t m arro w bio psy w ere : se rum iron , 200 jz g /1 00 m l; T .I .B .C .,24 0 /L g/1 00 m l; se ru m fo la te, 1 .0 ng /m l; an d serum B 1 2 , 360 0 pg /m l. A fter 3d ay s w ith no change in th e re ticu lo cy te co un t, fo lic ac id the rapy (5 0 g i.m ./day ) re su lted in a reticu lo cy tosis reach ing 41% .

In con tra st, in a pa tien t repo rted p rev iou sly w ith pe rn ic ious anem ia andasso cia ted fo la te de ficiency (se ru m B 12 , 20 pg /m l; se rum fo la te, 1. 8 ng /ml) ,th e m arrow , p rio r to trea tm en t w ith B 1 2 , ex h ib ited ab norm a l d U supp ressio n(6 2% ) w ith pa rtia l co rrec tion b y th e add ition o f B1 2 ( 4 8 % ) and fu rth e r co r-

rec tion b y the add ition of fo lic ac id ( 2 0 %) . N ine ty -six hou rs a fte r B1 2 therapy ,50 0 zg /day , the re ticu locy te coun t had risen from 3% to 1 5% , an d repea tm arro w revealed a reduced degree o f m orph o log ic m ega lob la stosis and am e lio -ra tion of th e abn orm al d U su ppression (29 % ). A dd itio n of B1 2 to the m arro wcu ltu re , in con tra st to p r e - B 1 2 the rapy , w as w ith ou t e ffect (dU supp re ssio n3 3 % ) w ith co m ple te co rrec tion by th e add ition o f fo lic ac id ( 5 %) . Serum B1 2


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28 VA N D E R W E Y D E N , R O T H E R , A N D FIR K IN

a t th e tim e of repea t m arrow w as 2300 p g /m l, an d fo late 0.9 n g /m l. A sim ila rpa ttern w as dem on stra ted in a p atien t (N o . 12 ) w ith fo la te de fic iency an dreduced se rum B1 2 be low the no rm al range . T h e m arrow prio r to treatm en twith B1 2 ex h ib ited abn orm a l d U supp ressio n (39 ) w ith pa rtia l co rrectio nw ith th e add ition o f B 1 2 (1 8% ) an d co m ple te co rrectio n w ith fo late (6 ) .F o rty -e igh t ho urs af te r com m enc ing B1 2 therapy (5 0 0 ,ig /day ) , repeat m arrowasp ira tion revealed a m od era te reduc tion in m ega lo b la stosis and asso cia tedreduc tion in abno rm al dU sup press ion (20 {176}k) , w ith no sign ifican t co rrec tionby th e add ition o f B 12 (1 8% ) an d com p lete co rrec tion by th e ad d ition offo late (2 ).

D I S C U S S I O NIn 14 2 pa tien ts w ith m ega lob la stic anem ia due to fo la te d efic ien cy , repo rted

by M ollin et a l., 47 % ex h ib ited depre ssed se rum B1 2 lev els and , in 1 0 % , th eleve l w as les s than 10 0 p g /m l. S im ila rly , s ix o f ten pa tien ts reported b yH ansen and W ienfield 3 and 12 of 21 pa tien ts w ith fo la te d eficien cy rep ortedby C oo pe r and L ow enste in2 h ad assoc ia ted su bno rm al B1 2 leve ls . In con tras t,ery th rocy te B1 2 lev els are inva riab ly lo w in fo la te d efic ien cy .9 T he e ffec t o ffo late th erapy on th e d ep re ssed serum B1 2 lev e ls is va riab le bu t gene rallyp ro duces a ris e in th e se rum B 1 2 . M ollin e t a l.1 repo rted tha t th e serum B1 2fa iled to rise con sequen t to fo late the rapy o n ly in p atien ts w ith coex is ten tm a labso rp tio n of B 1 2 . In the da ta rep orted by John son e t al.,7 desp ite a sign i-f ican t r ise in se rum B1 2 leve ls in 11 of 21 pa tien ts w ith trop ica l m a labso rp tio nreach ing a peak 3-17 days a fte r co m m enc ing fo lic ac id th erapy , in on ly fiv eo f the 11 p atien ts w as th is sus tain ed a t 30 days, and in on ly th ree w as th eserum B1 2 in excess o f 1 50 p g /m I. T he subn orm a l e ry th rocy te B1 2 lev els info la te de fic iency re tu rn to norm a l fo llow ing th e rapy .9 H o w eve r , in pa tien tsex h ib itin g assoc ia ted redu ced se ru m B 12 leve ls , the e ry th ro cy te B1 2 lev el fa iledto b e susta ined in the n orm a l range fo llo w in g fo lic ac id th erapy .9 T hem ech an ism s re spo nsib le fo r th e depre ssed e ry th rocy te o r se rum B1 2 levelsbe low th e n orm al rang e o r fo r th e su bsequ en t rise fo llo w in g fo lic ac id th erapya re specu la tive and unp ro ven .

T he co n trib u tion of the depressed serum B 1 2 in fo la te de ficiency to them ega lob la stic m a tu ra tion is d em ons tra ted by th is s tudy . In m arro w cu ltu reso b ta ined from p atien ts w ith B1 2 de ficiency an d assoc ia ted n orm a l o r in creasedse ru m fo la te leve ls , th e ab norm a l in co rpo ra tion of dU in to D N A -thy m ineis p artly co rrected by added B1 2 and com ple tely co rrec ted b y fo lic acid . { 176 } Inco n tras t, in pu re fo la te de fic iency , add ed B1 2 is w ith ou t e ffec t. T he pa tte rnexh ib ited b y pa tien ts w ith fo late de fic iency w ith coex isten t, dep re ssed serumB1 2 leve ls is sim ila r to tha t ob tain ed in pa tien ts w ith u ncom p lica ted B1 2 de -ficiency , n am ely p artia l co rrec tion of th e abnormal dU in co rp oratio n in toD N A by B1 2 w ith com ple te co rrec tion b y fo lic ac id .

T hese find in gs m ay b e exp licab le o n the b as is tha t the red uced se rum B1 2lev els in fo la te d efic ien cy rep re sen t fo r hem op o ie tic tissu e a true d efic ien cyat th at po in t in tim e . C on sequen tly , the resu ltan t im p a ired conv e rsio n o f5 -m e thy l- te trahy dro fo lic ac id (5M -T H F ) to tetrahyd ro fo lic ac id (T H F ), a B 1 2 -


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R E D U C E D B 1 2 IN F O L A T E D E F IC IE N C Y 29

d ep en den t step , { 17 6}20 2 and the dec reased cellu lar u p take of 5 M -T H F , p ossib lyB 12-depend en t,2 2 p o ten tia te the degree o f dep le ted tissu e lev els o f activ e fo latein term ed ia te s , w ith ensu ing redu ced conv ersio n of d U M P to d T M P , a fo la te -dependen t step .23 T h is concep t is sup ported by the find ing in th e p atien ts w ithbo th B1 2 and fo la te de fic iency , w he re the ad m in is tra tion of B1 2 re su lted in theconv e rsio n of th e m e tab o lic d efect conseq uen t to B1 2 de ficien cy , w ith co ex isten tred uc tion in m ega lob la stos is . H ow eve r, ev idence of abn orm a l dU incorpo ra -tion in to D N A , consequ en t to fo la te d efic ien cy , pe rs is ted . In co n trast, pha rm a-co log ic do ses o f B1 2 in a pa tien t w ith fo la te de ficiency b u t no rm a l se rum B1 2w ere w ith ou t e ffec t in red uc ing th e degree o f m ega lo b la stosis o r abno rm a l d Uincorpo ra tion in to D N A and w ere ine ffectiv e in indu cin g a re ticu lo cy tosis . T h isv ariance from th e find in gs o f Z a lu sky e t a l.2 4 m ay be exp licab le on the basistha t the pa tien ts stu d ied by th ese w orke rs h ad alcoh o lic liv er d is ea se an d m ayh av e had tissu e dep le tion o f B1 2 d esp ite no rm al se ru m B 1 2 , a phe nom eno nd em ons trab le in a lco ho lic live r d isea se .25

R E F E R E N C E S1 . M oil in , D . L ., V V aters, A. H., and

H a rris , E .: C lin ica l a spe cts o f the m e tab o licin te rre la tionsh ip betw ee n fo lic a cid an dv i tamin B 1 2 . In H ein ric h , H . C . (E d .): V ita -mi n B1 2 and In trin sic F a cto r, 2 E uropa isc hesS ym po sio n . S tu ttg art, E n ke , 196 1 , p . 737 .

2 . C o ope r, B . A ., and L o w e nste in , L .: V ita -m in B 1 2-fo la te in te rre la tionsh ip s in m e ga-lob las tic ana em ia. B rit. J . H a e m a t . 12: 283 ,1966 .

3 . H a nse n , H . A ., a nd W ie nfie ld , A .:Metabolic effects and diagnostic value ofsm all doses of fo lic ac id and B 12 in m e galo-b ia stic an ae m ia s. A cta M e d. S ca nd . 17 2:4 27 ,1962 .

4 . C h ana rin , I .: T he M e galob iastic A n ae-m ias (ed . 1) . O xford an d E din bu rgh , B la ck-well, 1 96 9 , p . 22 0 .

5. S co tt, R ., K am m er , R ., B urg er , W .,an d M idd le ton , F .: R edu ced absorp to in ofv i tamin B 12 in tw o p atien ts w ith fo i ic ac iddeficiency . A nn . In te rn . M ed . 69:111 , 19 68 .

6 . H if t, W ., an d A d am s, E . B .: M aiab -sorp tio n of v ita m in B 12 in m ega lob las ticana em ia a m o ng A fr ican s and Ind ians inD u rba n . T rans . R oy . S o c. T rop . M ed. H y g.57: 445 , 1 9 6 3 .7. Johnson , S., Swaminathan, S. P., andB ak er, S . J. : C h an ges in S e rum B 12 lev elsin pat ien ts w ith m eg alo b la stic a nae m iat re at ed wi th fol ic ac id . J. Cii n. P at h. 15: 274 ,1 9 6 2 .

8 . M oilin , D . L ., and R o ss , C . I . M .: V ita -

m m B 1 2 def ic ie ncy in th e m eg alo b ia stican aem ia s. P ro c. R oy . S o c. M e d. 47 :428 ,1 9 5 4 .

9. K iilm a n , S . A .: E f fect o f de ox yur id in eon inc orp ora tio n of trit ia te d thym id ine . D if-fe ren ce b etw een norm o bla sts a nd m ega lo-b lasts. A cta M e d. S ca nd . 17 5:4 83 , 1964 .

10 . M etz , J. , K elly , A ., S w e tt, V . C ., W a x-m an, S . , an d H erb ert, V .: D e ran ged D N Asy nth esis by bon e m arrow fro m vitam inB1 2 d efic ien t hu m a ns. B rit. J. H a e m a t .1 4 :575 , 1 968 .

1 1 . V a n D er W ey de n , M . B ., R o the r, M .,an d F irk in , B . C .: M e galo b lastic m atura tio nm a sk ed by iro n def ic ie nc y : A bio che m icalba sis. B ri t. J. H a e m a t . 22 : 299 , 1 9 7 2 .

12 . F eine nd ege n , L . E ., B ond , V . P ., a ndP ain ter, P . B .: S tu d ie s on the in terre la t ion -sh ip o f R N A sy nth esis, D N A syn the sis a ndprecu rso r poo l in hum an tis sue cu ltu re ce llsstu d ie d w ith tri tia ted py rim id ine p rec ur-so rs. E x p . C ell R e s. 2 2 :3 81 , 1961 .

13 . C o op er, H . L ., an d R u bin , A . D .: R N Am eta bolism in lym ph ocy tes s tim ula ted b yph yto hae m a gglu tin : In it ia l respon se to phy -toh ae m a gglu tin . B lood 25 :10 14 , 196 5 .

14 . M atthew s, D . M .: O b serv ation on thees tim ation of se rum B 1 2 us ing L ac t obac i l l u sl e i c hm ann i i . C lin . S ci. 2 2 :1 01 , 196 2 .

15 . H erber t , V .: A sep tic a dd itio n m eth odfo r L a cto ba cillu s c ase i assay of fo ia teac tiv i ty in h um an se rum . J. C lin . P ath .19 :1 2 , 196 6 .


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30 VAN DER WEYDEN, ROTHER, AND FIRKIN

16 . Isenberg, J . I., B rooks , A . M ., an dC rossm an , M . I.: Pen tagas trin vs . be tazo leas stim ulan t o f gastric sec re tion . JA M A206:28 97 , 19 68 .

1 7 . S eg al, H . I., M il ler , L . L ., an d P lu m b ,E. J. : T ube les s ga stric an aly sis w ith anazure-a ion-exchange compound. Castro-en tero logy 28:402 , 1 95 5 .

18 . N airn , R . C .: F luo rescen t P ro te inT ra cin g . E d inb urg h L iv ing sto ne, 196 9 , p .111 .

19 . H a rrison , R . J. : V itam in B 1 2 lev els inery th roc y te s in an aem ia d ue to fo la te d e-fic ien cy . B rit. J. H ae m a t. 2 0 :6 23 , 1 97 1 .

20 . H erber t , V ., L a rrab ee, A . B ., a ndB u c h a n a n , J. M .: S tu d ie s o n the iden tifi -cat ion of a fo late co m p ou nd o f hum anse ru m. J. C lin . Inves t . 4 1:1 134 , 1 96 2 .

21 . H erbert, V ., and Z alusky , R .: In ter -rela tions o f v itam in B1 2 and fo lic acid

metabolism: Folic acid cleara nce studi es.J. C lin . Inv est . 41 :12 63 , 1 962 .

22. Das, K. C ., a nd H offb ran d , A . V .:S tu d ies of fo late up take by ph yto hae m a g-g lu tm n in-stim ulated lym ph ocy tes . B rit . J.H ae m a t. 19 :203 , 19 70 .

23 . P a sto re , E . J. , and Fri edkin, M.: Th eenzymatic synthesis of thymid ylate. II.T ra nsfe r o f tritium from tetrah ydrofo lateto the m eth y l group of thy m id yla te . J. Biol .C hem . 237 :38 02 , 1 962 .

24 . Z a lusky , R ., H erb ert , V ., and C as tle ,W . B .: C y ano cob ala m in the rap y : E ffec t info lic acid def ic ie nc y . A rch . In tern . M ed .1 09:91 , 1 962 .

25 . H erb ert , V .: D iagn ost ic an d p rog -no stic va lue s o f m e asu rem en t o f serumvitamin B1 2 bind ing pro teins. B lo od 3 2:3 05 ,1968 .

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