Biochimica et Biophysica Acta, 1084(1991) 173-177 © 1991 ElsevierSciencePublishersB.V.0005-2760/91/$03.50 ADONIS 000527609100198H

173

The fatty acid composition of placenta in intrauterine growth retardation Phyllis P e r c y 2, G u d j o n V i l b e r g s s o n 1, A l a n P e r c y 2, J a n - E r i c M h n s s o n 2, Margareta Wennergren i and Lars Svennerholm 2 i Department of Obstetrics and Gynaecology, Sahlgren's Hospital. University of G6teborg, G6teborg (Sweden) and " Department of Psychiatry and Neurochemistry, St. J6rgen Hospital, UnitJersityof G~teborg, Hisings Backa (Sweden)

(Received14 December1990) Key words: Essentialfatty acid. Intrauterinegrowthretardation; Phosphatidylcholine;Phosphatidylethanolamine;(Human placenta) To examine the impact of intrauterine growth retardation (IUGR) on essential fatty acids in human placenta, fatty acid composition in total acylglycerol and in the major phespbuglycerides pbusphatidylcholin~ (PC) and plmsphatidylethanolamine (PE), of 15 placentas from small for gestafional age (SGA) births was compared with that of 7 control placentas. The acylglycerol fatty acid content was similar between the two groups, but the proportion of fatty acids of the linole|c acid series, including arachidonie acid, was significantly lower in SGA placentas. When the fatty acid composition in PC was studied, the reduction in fatty acids of the linoleie acid series was even more striking, and fatty acids of the linolenie add series were also sisnif~cantly less in the SGA group. These fatty acid changes in placenta membrane plmspholiplds can affect the transport of important nutrients to the fetal compartment. The decreased level of arachidonic acid and dneosahexanoic acid might also lead to a disturbed formation of fetal thromboxane and prostacyclin. However, cord plasma PC fatty acid patterns were nearly identical in the two groups suggesting that in IUGR, the essential fatty acids will he wansported to the fetus at *.he expense of the placenta.

!ntraduction Intrauterine growth retardation (IUGR) has been attributed in part, to defective placental function and with it reduced transport of critical nutrients to the fetus. Recent animal data have indicated that glucose transport was virtually unimpaired in IUGR produced by uterine artery figation whereas amino acid transfer was significantly reduced [1]. Placenta transport of essential fatty acids (EFA) is also crucial for normal fetal growth and development. In previous work from members of the present study [2], the hypothesis that EFA deficiency occurred in IUGR was addressed comparing the serum lecithin fatty acid content of maternal and cord blood from appropriate for gestatienal age (AGA) and small for gestational age (SGA) pregnancies. In order to elucidate further the essential fatty acid patterns in IUGR we have examined the acylglycerol fatty acid patterns in the term placenta from AGA pregnancies and for preterm and term placenta from Correspondence:L. Svennerholm,St. J~rgen Hospital,422 03 Hisings Backa, Sweden.

SGA and compared these data with plasma lecithin fatty acid patterns derived from materual and cord blood obtained at birth. Material and Methods Clinical material

The study material consisted of placentas from 22 human pregnancies, 7 from full term AGA pregnancies and 15 from SGA pregnancies, 6 preterm and 9 term. The study was approved by the Ethics Committee, University of G~teborg. After ultrasound screening and dating of all pregnancies in gestafional weeks 16-17, screening for IUGR of the whole pregnant population was performed in gestational week 33 according to Wennergren et al. [3]. Controls were recruited from those with no risk factors. All pregnancies considered to be at risk for IUGR were sonogrammed for fetal malformations and the fetal weight was estimated. According to the reference curve used [4] fetal weight deviation was calculated in percent. By using this reference curve one standard deviation equals 11~ of the mean. The cut-off point for intensified mt~m~oring was set at the - 159~ level. Pregnancies enrolled in the study

174 as risk cases all had estimated fetal weight deviation greater than 22% below normal values, and controls above 11% below the mean. Artenatal monitoring of all risk pregnancies was performed wilh non-stress test. oxytocin challenge test, Doppler flow measurements, biophysical profile and weight estimation every 2 weeks. The intensity of the monitoring was adjusted to the severity of growth retardation. After delivery the placenta was immediately placed at + 4 ° C . A venous blood sample (5 ml) was collected from the mother in an EDTA-tube within 15 rain of delivery and a cord blood sample (3-5 ml) immediately after birth. The placenta and the blood samples were transported on ice to the neurochemical laboratory within 2-3 h.

('hemicals All chemicals were of analytical quality and organic solvents of HPLC quality. TLC plates of silica gel 60 were obtained from Merck AD (Darmstadt, Germany).

Tissue preparation The further handling of the placentas was performed in a laboratory of + 4 ° C in which all solutions had the same low temperature. The placenta was washed with physiological saline by pressing the tissue against the wall of a small beaker with a glass rod until the supernate was free of visible blood. The tissue was pressed against filter paper until extra fluid was removed. All tissues not utilized immediately were frozen in tightly sealed containers at - 2 0 °C until analyzed.

Quantitative determinations of placental acylglycerol fatty acids 1-2 g of placenta were weighed, frozen in liquid nitrogen, axed homogenized by mortaring. Duplicates of 100 mg were used for lipid extraction and duplicates of 100 mg for the determination of dry weight. For lipid extraction, the tissue was suspended in 0.5 ml water in a glass tube with Teflon-lined screw cap to which 2 ml methanol and 1 ml chloroform were added. The mixture was shuttled for 15 min on a rocking platform and centrifuged at 3000 x g for 10 rain. The supernate was transferred to a new glass tube and the solvent evaporated under a gentle stream of nitrogen on a water bath of 50 ° C. 1 ml 0.2 M sodium methylate in methanol was added to the residue followed ey 100 nmol 17:0 fatty acid methyl ester dissolved in 0.1 ml methanol. The mixture was allowed to stand for 1 h at 37°C and then acidified with 0.15 ml 2 M acetic acid. The mixture was extracted with 3 x 1 ml light petroleum and the combined petroleum extracts were washed twice with 1 ml water. The petroleum phase was evaporated to a small volume under a gentle stream of nitrogen on a water bath of 37 ° C and spotted as a 3 cm wide band on a 20 × 20 cm silica gel 60 TLC plate. Thc plate was

developed in light petroleum/diethyl ether/acetic acid (85 : 15 : 1, v/v) and sprayed with bromophenol blue as soon as the organic solvents were evaporated. The methyl ester zone was collected by scraping, mixed with 2 ml methanol and shaken thoroughly. The mixture was extracted sequentially with "~× 1 ml light petroleum. The combined light petroleum extracts were washed with 2 × 1 ml H20, evaporated to a small volume and placed at - 2 0 ° C until analysis (within a week).

Separation of placental phosphoglycerides, phosphatidylcholine and phosphatidylethanolamine and determination of their fatty acid composition Placenta (1-2 g) was homogenized by freezing and mortaring as above. The tissue was extracted in a glass tube with a Teflon-lined screw cap with 2 volumes water, 8 volumes methanol and 4 volumes chloroform to a final volume of 15 ml and shuttled for 30 min. The mixture was centrifuged at 3000 × g and the supernate was transferred to a small round-bottom flask and evaporated to dryness. The residue was re-extracted with 10 ml chloroform/methanol/water ( C / M / W , (60:30:4.5), and the stoppered flask was allowed to stand at least 1 h at room temperature. The extract was added to a 2 g column of Sephadex G25. The flask was rinsed with 5 ml C / M / W (60:30:4.5), which was added to the column. The column was eluted with 10 ml C / M / W (60:30:4.5) and 5 ml C / M (2:1) and the combined extracts were evaporated to dryness. The extract was redissoived in 5 ml C / M / W (60:30:4.5) and the mixture was added to a column with 1.6 ml DEAE-Sepharose (acetate form). The flask was rinsed with 5 ml C / M / W (60:30:4.5) which was added to the column. The column was eluted with an additional 10 ml of the same solvent. The combined eluates contained the neutral phospholipids: ethanolamine- and cholinephosphoacylglycerols and sphingomyelin. The neutral fraction was evaporated to dryness and dissolved in 0.1 ml C / M (2 : 1), spotted as a 5 cm band on a silica gel 60 TLC-plate (20 .'< 20 era) along with references for phosphatidylethanolamine (PE) and -choline (PC). The plate was developed in C / M / W (65:25:4) for 1 h. After thorough drying, the plate was sprayed with bromothymol blue and the PE and PC zones scraped into a conical tube. The isolated neutral phosphoglycerides were placed in a desiccator overnight (P205) and the following day were methylated as described above.

Dry weight determination The samples for dry weight determination were lyophillzed for 48 h and then dried to constant weight over granulated phosphorous pentoxide in a vacuum desiccator. They were weighed immedia:e!y after they were taken out from the desiccator. Total nmol of fatty acid were expressed per milligram of dry weight.

175

Determination of plasma phosphatidyk'holine &tt;, acid composition The procedure described by Oleg~rd and Svennerholm [5] was used with minor modifications. The plasma was obtained by centrifuging the respective blood samples at 2250 × g for 15 min and extracted in duplicate by adding 0.5 ml dropwis,: into two Exelo tubes (110 × 17 mm) containing 8 ml C / M (1 : 1) each. The tube was capped, shaken vigorousl'¢ for 1 rain and centrifuged at 1200 :x: g for 10 min. The supernate was transferred to a graduated tube and mixed with 2.5 ml acidified (4 mM H2SOa) 0.9% NaCl. The upper phase was removed and the lower phase diluted to 5 ml with methanol. 1 ml of lipid extract was evaporated almost to dryness under nitrogen ( 3 7 ° C ) and 0.1 ml C / M ( 2 : 1 , v / v ) was added. The lipid extract was applied as a 3 cm wide band on a TLC plate (20 × 20 cm), which was developed in C / M / W ( 6 5 : 2 5 : 4 , v / v ) for 1 b. After drying, the plate was sprayed with bromophenol blue and the phosphatidylcholine band was scraped out. The gel was dried overnight in a vacuum desiccator over granulated phosphorous pentoxidc. 2 ml of 0.2 M sodium methylate in methanol were added and alkaline transmethylation was performed at 3 7 ° C for l h. After addition of 0.3 ml 2 M acetic acid, the fatty acid methyl esters were extracted with 3 × 1 ml of light petroleum. The combined petroleum extract was washed twice with l ml water and stored at - 2 0 ° C until analysis (within l week). Gas liquid chromatography (GLC) and quantitation of fatty acid methyl esters All extraction, isolation and quantitation procedures of fatty acid methyl esters were performed with the previously described methods from our laboratory [5,6]. The methyl esters were analyzed on a Perkin-Elmer F22 gas chromatography equipped with a glass column (2 m x 12 m m i.d.) packed with 15% D E G S on C h r o m s o r b W, HP (80-100 mesh). Peak areas were determined with a Perkin-Elmer Chrom 3 chromatography data system. The fatty acid compositions are given as molar percentage. The coefficient of variation (C.V.) for analysis of total placenta acylglycerol fatty acids from duplicate samples was determined. These C.V. values included all steps in the procedure from extraction to G L C analysis. The values for c o m p o n e n t s constituting more than 20 utol% of the fatty acid composition were < 2%, for components between 10-20 mol% < 3%, for components between 2 - 1 0 mol% < 5% and for c o m p o n e n t s less than 2 mol% < 10%. Data analysis Statisticai analysis was accomplished with S A S / STAT (SAS Institute lnc, Cary, NC, U.S.A.) regression analysis and analysis of variance (6.03 Edition).

Results

Clinical results The outcome of the pregnancies is shown in Table I. There were no differences between the groups regarding=, maternal age or parity. Nine of the SGA cases had cesarean sections, three because of ominous signs in the antenatal monitoring, two for maternal reasons, two owing to fetal growth stagnation, one due to failed induction and one as the result of abruptio. Three had normal de!iveries and three induced deliveries. All seven of the controls were delivered vaginally. "l-he A G A group demonstrated small variation in the respective parameters. Conversely, the SGA grottp showed significant variability, and, in particular, birth weight values varied by more than three standard deviations. Phlcenta fat O, acid anal_vses To validate the tissue collection and preparation methodology, placentas from one term A G A birth and one term SGA birth were processed within 6 h of delivery. Duplicate samples of 5 g were dissected from each placenta, frozen, homogenized by mortaring and analyzed as described under Materials and Methods. The values for the acylglycerol fatty acid concentration in the A G A samples were the same, 114 # m o l / g dry weight, with the same fatty acid pattern. The corresponding values for the SGA placenta were 95 and 83 b t m o l / g dry weight with no difference in the fatty acid pattern. To determine the m a x i m u m contribution of blood to the placenta fatty acid values, all retained blood from the A G A placenta was collected. From the placenta weighing 250 g, 15 ml of blood was obtained. The blood contained 8.5 p, mol acylglycerol fatty a c i d s / g and the placenta 2 3 / t m o l fatty a c i d / g wet tissue. Thus, retained blood did not contribute more than 2% of total placenta acylglycerol fatty acids. Placenta was available from 7 A G A and 15 SGA (6 preterm and 9 term) births and duplicate samples from each were analyzed for dry weight, acylglycerol fatty acid content and the distribution pattern of acylglycerol fatty acids. The mean values for dry weight ( g / 1 0 0 g wet weight) and total acylTABLE I

( hntcal data o/newhorn.x from pregmlnctes approprtate ]or gestammal a~.e (.,!(;.-I) trod smallfiJr g~tational age (S(;A) Values represent means_+S.D. AGA ( n = 7)

StJA ( n = 15)

Malernal agelyrsl 30.7+ 5.4 28.9+ 5.0 Ges:ational age(wl 40.5+ 0.9 36 _+ 4 Birth weight (g,~ 3876 + 296 1841 +698 Birth weight deviation (%) " 5.1 + 8.2 - 35.6_+ 8.9 Birth length (cm) 50.6_+ 1.0 42.1 + 4.8 ' Deviation from the reference values [4I.

Levelof ~,ignificance n.s. P < 0.001 P < 0.001 P < 0.001 P < 0.001

176 TABLE II

TABLE IV

Dr). weight and acylglycerol fatty acid content in placentas from pregnancies appropriate for gestational age (AGA) and small for gestational age (SGA) Values represent means+-S.D. The determinations were performed as described under Materials and Methods.

Phosphatidylcholine fatty acid composition in placentas from pregnancies appropriate for gestational age (AG.4) and small for gesmtional age (SGA) Values represent means+S.D. Values less than 1 tool% are not listed for individual fatty acids but included in n - 6 and n - 3 series.

AGA (n=7) Dry weight (g/100 g wet weight) Acylglycerolfatty acids ( # mol/g d~ weight)

SGA (n=lS)

17.4+- 3.2

18.5+ 2.1

126.4+ 25.1

116,8 + 52.5

glycerol fatty acid content ( # m o l / g dry weight) f r o m the 7 A G A and 15 S G A placentas were virtually identical (Table II). T h e distribution of fatty acids, however, revealed some differences (Table III). T h e proportions of 1 6 : 0 and 1 8 : 0 fatty acids were greater in S G A placenta, and the proportions of 20 : 3(n - 6) and 20 • 4 were less in S G A placentas. T h e s u m of n - 6 fatty acids was less in the S G A placentas. As the s u m of n - 3 fatty acid in S G A placentas was slightly lower, the fatty acid pattern in individual lipid classes was further explored by isolation and analysis of PC a n d PE. T h e reductions found in S G A placenta fatty acid coml~osition were also present in PC fatty acids ( T a b l e iV). However, the reduction in S G A n - 6 fatty acids in PC was even more m a r k e d and, in addition, n - 3 fatty acids were significantly lower. In contrast, no differences between A G A and S G A placenta were noted in the polyunsaturated fatty acid composition of PE (Table V). M a t e r n a l a n d cord p l a s m a P C f a t t y acid p a t t e r n s f r o m A G A and S G A births Comparison of maternal and cord p l a s m a PC fatty acid profiles from the A G A and S G A groups is de-

Fatty acid

AGA ( . = 7)

SGA (n = 15)

16:0 18:0 18:1 18:2 20:3(n-6) 20:4(n-6) 22:4(n - 6 ) 22:6(n-3) Total n - 6 Total n - 3

35.8+2.3 9.0+-1.0 12.5+-0.9 11.0±0.8 4.84-0.4 20.1+1.5 0.4+0.1 2.6+0.5 36.6 + 1.5 3.1 +0.7

44.3±9.1 10.04-1.1 11.9+1.5 9.2±1.7 3,5+1.3 15.7+5.3 0.4+0.1 1.8+1.1 28.9 + 7.4 1.9+1.2

Level of significance 0.006 0.05 n.s. , 0.005 0.005 O.O1 n.s. n.s. 0.003 0.04

picted in T a b l e VI. In general, the fatty acid composition was the s a m e in both m a t e r n a l groups and in b o t h cord groups. H o w e v e r , m a t e r n a l p l a s m a PC fatty acid patterns revealed a difference for 22 : 6(n - 3), n a m e l y 4.9% in S G A a n d 3.6% in A G A samples ( P < 0.02) a n d cord p l a s m a PC f r o m the S G A g r o u p contained less 20 : 3(n - 6 ) ( P < 0.02).

Discussion T h e placental transfer of long-chain, p o l y u n s a t u r a t e d fatty acids f r o m the m a t e r n a l to the fetal c o m p a r t m e n t in - n a m m a i s is weU-established [7]. I n particular, 2 0 : 4 ( n - 6) is transported pref,~rentially into the fetal c o m p a r t m e n t . F u r t h e r m o r e , the i m p o r t a n c e of the n - 3 series, especially 22 : 6(n - 3), has received recent attention with r e g a r d to fetal a n d post-natal d e v e l o p m e n t of

TABLE V TABLE II[ Acylglycerol fatty acid composition in placentas from pregnancies appropriate for gestational age (.4GA) and small for gestational age (SGA) Values represent means + S.D. Values less than 1 mol% are not listed for individual fatty acids but included in n - 0 and n - 3 series. Fatty acid 16:0 18:0 18:1 18:2 20:3(n-6) 20:4(n-6) 22:4~n -6) 22 : 6(n -3) Total n - 6 Total n - 3

AGA (n = 7)

SGA ( n = 15)

Level of Significance

2~ 3-: 1.4 13.9+0.6 14.3+1.1 10.7+0.7 5.3+0.3 20.6+1.5 1.34-0.1 4.15:0.9 38.8 + 1.6 5.3±1.0

27.6+2.9 15.9+1,7 13.2+1.5 9.9+1.5 4.3+0.9 18.9+1.9 1.5+0.2 3.94-0.5 35.2 + 2.9 4.8±0.6

0.02 0.001 n.s. n.s. 0.00l 0.05 n.s. n.s. 0.01 n.s.

Phosphatidylethanolamine fatty acid composition in placentas from pregnancies appropriate for gestational age (AGA) and small for gestatioaal age (SGA) Values represent means±S.D. Values less than I molq~ate not listed for individual fatty acids but included in n - 6 and n - 3 series. Fatty acid

AGA (n = 7)

SGA ( n = 15)

Level of Significance

16:0 18:0 18:1 18:2 20:3(n-6) 20:4(n - 6 ) 22:4(n - 6 ) 22:5(n - 3 ) 22 : 6(n - 3) Total n - 6 Total n - 3

IO.3±lA 18.1::1:1.3 14.45:.0.6 6.6+0.6 4.4+0.4 28.6+2.3 2.4+0.4 1.4+0.1 10.2 4-1.5 43.8+3.0 12.0+1.5

13.0+5.4 20.3+2.3 13.7+2.6 6.4+1.4 3.8 :t:0.9 27.0+4.7 2.6+0.6 1.4+0.5 8.7 4-3.2 41.2+4.4 10.3±3.8

n.s. 0.04 n.s. n.s. n.s. n.s. n.s. n.s. n.s. n.s. n.s.

177 TABLE VI Phosphatidylcholine fatty acid composition in maternal plasma and umbilical cord plasma in pregnancies appropriate for gestational age (AGA) and small for gestational ag~ (SGA)

Values represent means + S.D. Values less than 1 tool% are not listed for individual fatty acids but included in n - 6 and n - 3 series. Fatty acid

Maternal plasma AGA SGA (n = 7) (n = 15)

16:0

33.5+1.5 10.7 4- 0.9 15.54-0.8 20.8+1.1 3.8+0.3 7.44-1.0 3.6+0.8 32.5+1.1 5.1 4-0.9

32.54-2.5 10.9+ 1.5 15.7+1.8 20.7+3.4 3.85:0.7 7.65:1.6 4.9+1.3 32.5+3.6 6.1 + 1.7

Cord plasma AGA n=7

n=15

32.24-2.1 15.5+0.6 13.5+1.0 8.5+1.0 5.34-0.8 14.4+1.0 5.45:0.6 29.14-1.7 6.64-0.8

34.1+2.8 14.3+2.3 13.95:2.4 9.6+1.7 4.3+0.8 14.5+2.4 5.25:1.5 29.2+ 3.2 6.25:1.7

18 : 0

18:1 18:2 20:3(n-6) 20:4(n-6) 22:6(n-3) Total n - 6 Total n - 3

16:0 18:0 18:1 18:2 20:3(n-6) 20:4(n-6) 22:6(n-3) Total n - 6 Total n - 3

Level of significance n.s. n.s.

n.s. n.s n.s. n.s. 0.02 n.s. n.s.

SGA u.s. n.s. n.s. n.s. 0.02 n.s. n.s. n.s. n.s.

the central n e r v o u s s y s t e m [8-10]. T h e potential i m p a c t o f d i s t u r b e d f a t t y acid t r a n s p o r t o n the, genesis o f i n t r a u t e r i n e g r o w t h r e t a r d a t i o n is u n k n o w n . T h e present s t u d y d e m o n s t r a t e s n o differences in acylglycerol f a t t y acid c o n t e n t b e t w e e n p l a c e n t a s f r o m A G A a n d S G A births. H o w e v e r , the r e d u c t i o n o f n - 6 series fatty a c i d s i n c l u d i n g 2 0 : 3 a n d 2 0 : 4 in S G A p l a c e n t a acylglycerol f a t t y acids a n d the even m o r e striking r e d u c tion of the n - 6 series plus a lower n - 3 series, p a r tieularly 2 2 : 6 , in P C fatty a c i d s is relevant a n d supp o r t s a d i s t u r b a n c e in p l a c e n t a f u n c t i o n in I U G R . T h e failure to find c o r r e s p o n d i n g c h a n g e s in the PE fatty acid c o m p o s i t i o n f r o m S G A p l a c e n t a s is not surprising. T h e effects o f variation in the d i e t a r y s u p p l y o f essential f a t t y acids will be m o r e p r o n o u n c e d in PC t h a n in PE. T h i s was clearly d e m o n s t r a t e d in several o r g a n s o f rats p r o v i d e d diets differing in essential fatty acids ( E F A )

w h e r e a decreased s u p p l y of E F A led to a significant decrease in the p r o p o r t i o n s of fatty acids of linoleic a n d linolenic acid series in PC b u t not in P E [11]. The c h a n g e s n o t e d in S G A p l a c e n t a could lead to alterations in fatty acid t r a n s p o r t to the fetal c o m p a r t m e n t o r alter the integrity of p l a c e n t a l function with respect to the t r a n s p o r t of essential n u t r i m e n t s . F u r t h e r , the n - 6 series, p a r t i c u l a r l y 20 : 4, represent i m p o r t a n t p r e c u r s o r s of p r o s t a g l a n d i n s . T h e observed c h a n g e s could be relev a n t for p l a c e n t a l function, b u t a d d i t i o n a l d a t a will be necessary to a d d r e s s this issue. In r e g a r d to the fatty acid t r a n s p o r t , the lack of differences in c o r d p l a s m a fatty acid c o m p o s i t i o n between the t w o g r o u p s indicates n o iliajor difficulty in fatty acid t r a n s p o r t to the fetus.

Acknowledgments W e a c k n o w l e d g e the excellent technical assistance of Birgitta T r o ~ n g a n d t h a n k B a r b r o L u n d m a r k for prep a r i n g the m a n u s c r i p t a n d Steven W a r i n g for the statistical analysis. T h e s t u d y has b e e n s u p p o r t e d in p a r t b y a g r a n t f r o m the Swedish Medical R e s e a r c h Council, N o 003X-627. A K Percy w a s at the time of the s t u d y a Visiting Professor f r o m Baylor College of Medicine, H o u s t o n , TX, U.S.A.

References

1 Jansson, T. and Persson, E. (1990) Pediatr. Res. 28, 203-208. 2 Vilbergsson, G., Samsioe, G., Wennergren, M, and Karlsson, K. (1991) Int. J. Gynec~!. Obstet.. in press. 3 Wennergren, M., Karlsson, K. and OIsson, A. (1982) Br. J. Obstet. Gynaecol. 89, 520-524. 4 Eik-Nes, S.H., Grtittum, P., Persson, P.H. and Marshl, K. (1982) Acta Obstet. Gynecol. 61, 57-58. 5 0 l e g ~ d , R. and Svennerholm, L. (1970) Acla Paediat. Scand. 59, 637-647. 6 Svennerholm L. (1968) J. Lipid Res. 9, 570-579. 7 Kuhn, H. and Crawford, M.A. (1986) Prngr, Lipid Res. 25, 345353,

8 Clandinin, M.T., Chappeh JE., Heim, T., Sawyer, P.R. and Chance, G.W. (1981) Early Hum, Dev, 5,1-6. 9 Bazan, N.G. (1990) in Nutrition and the Brain (Wurtman, R.J. and Wurtman, J.J., eds.), Vol. ,~, 1990, pp 1-24, Raven Press, New York. 10 Lind, D.S., Connor, W.E.. Andersson, G.l. and Neuringer, M. (1990) J. Neurochem. 55,1200-1207. ll Bruce, A. (1974) Phosphoiipids of the Skeletal Muscle, Thesis, GiSteborg University, G~teborg.

The fatty acid composition of placenta in intrauterine growth retardation.

To examine the impact of intrauterine growth retardation (IUGR) on essential fatty acids in human placenta, fatty acid composition in total acylglycer...
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