Maternal and fetal ethanol pharmacokinetics and ...

Maternal and fetal ethanol pharmacokinetics and cardiovascular responses in near-term pregnant sheep M. E. CUMMING, B. Y. ONG,9. G. WADE,A N D D. S . SITAR' Depczrtnmerzt of Anesthesicz ant/ Clinical Phurnznc-ologvSec.tion. Fuc*mlPtyof Mctlic-ine, University c$Munitohu, Wirznipeg, Mcrn., Canutl(i R-3E OW-?

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Received February 29. B 984 CUMMIPIG, M. E., El. Y. ON&;,J . G. WAI?E,and D. S. SIT.AR.1984. Materrla! and fetal ethanol pharmticokinetics and cardiovascular responses in near-term pregnant sheep. Can. J . Physiol. Pharnnacol. 52: 8435- 1439. The disposition and cardiovascular effects of ethanol were studied in ncar-term pregnant sheep and thcir fetuses rafter intravenous infusions either to the mother or the fetus. Placental transfer of ethanol from mother to fetus was rapid, but transfer from the fetal to maternal circulation was impaired when ethanol was ridmi~nisterecldirectly to the fetus. Plasma clearance of ethanol was similar from the mother and fetus in utero. In the maternal infusion cxperirnents, both maternal and fetal heart rate increased with plasma ethanol concentration. However, in the fetal infusion experiments, fetal heart rate was irmversely related to plasma ethanol concentrations while maternal mean arterial blood pressure increased with maternal plasma ethkanol concentration. Further studies in neonatal lambs are needed to determine if ethanol has adverse effects on helrreodynamics when the neonate is separated from its protective intrauterine environment. CUMMIPIG, M. E., B. Y. ONC;,J . 6 . WADEet I). S. SITAM.1984. Maternal and fetal ethanol pharmacokinetics and cardiovascular responses in near-term pregnant sheep. Can. J . Physiol. Pharmacol. 52: 1435- 1439. On a examine, chez des brebis a I'approche du ternie ct chez leurs foetus, la rkpartition et les effets cardiovasculaires de l'ithanol aprks des perfusions iintraveineuses tant 2 la mkre qu'au foetus. Le transfert d'kthanol dc la mere au foetus fut rapide, mais celui de la circulation foetale a la circulation maternclle, observ6 lorsqu'on administra I'ethanol directement au foetus, fut plus lent. La clairance plasmatique de l'ithanol de la mere et du foetus fut similaire in altero. Dans Ies experiences de perfusion maternelle, la frequence cardiaque tant maternelle que foetale augmenta avec la concentration d'kthanol plasmatique. Toutefois, dans les expkriences de perfusion foetale, la friquence cardiaque foetale fut inversement reli@eaux concentrations d'Cthanol plasmatique alors que la pression artirielle moyenne maternelle augmenta avec la concentration d'kthanol plasmatique maternelle. D'autres Ctudes sur le mouton neonatal permettraient de determiner si I'ethanol a dcs effets nkgatifs sur l'hemodynamique lorsque le nouveau-nk est separ6 de son environnement intra-utkrin protecteur. [Traduit par le journal]

Introduction It is estimated that 39-4596 of women drink alcohol occasionally and 3-9% of them have one or two drinks daily throughout pregnancy (Oullette et al. 1977). Fuchs ~t ale ( 1967) have shown that ethanol has inhibitory effects on uterine activity and it has been used to treat premature Alcohol ingestion in pregnancy has been associated with effects on the fetus (Halap and Shiono 1980; Kline et 1980; Little 1977: Oullette el a6. 1977). Previous studies in the &)regnant sheep model concerning the effects of ethanol on the fetus have yielded conflicting data. Some studies have shown fetal metabolic acidosis and hypotension (Mann et al. 1975), increased Po2 and hypertension (Ayromlooi et al. 1979), and tachycardia (Ayromlooi et al. 1979: Cook et al. 1901; Mann et al. 1975) with ethanol administration. Maternal tachycardia (Cook et al. 1981; Rose et ul. 1981 ) and hypertension (Rose et al. 1981) have also been demonstrated. Others have not been able to elicit phamacodynamic changes (Kirkpatrick et cul. 1976; Rose et al. 1981; Ng et ale 1982; Dllts 1970). Using the pregnant sheep model, it Is possible to study the fetus in a relatively undisturbed intrauterine environment. Determination of the extent of fetal exposure is facilitated by this model which permits serial blood sampling over time (Szeto 1982). The present study used this approach to determine the kinetics of placental transfer and eliminatlon of ethanol in pregnant ewes, and to simultaneously assess the effects of ethanol on maternal and fetal cardiovascular status and acid -base balance. 'Author to whom all correspondence should be sent at the following address: Department of Pharmacology and Therapeutics, University of Manitoba, 770 Bannatyne Avenue, Winnipeg, Man., R3E 0W3.

Methods Studies were performed on healthy, tirne-dated, mixed-breed, nearterm pregnant sheep, weighing 60-80 kg, and on their fetuses. gestational age 124- 141 days (term 150 days). At least 2 days ~ r i o to r study. each ewe was anesthetized with 1.5% halothane in oxygen. intubated, and ventilated to maintain normal arterial Pco2. Maternal femoral arterial and vermous catheters were inserted. Through a midline incision the uterus was exposed and a small hysterotomy incision was made. A fetal hindlimb was withdrawn and polyvinyl cathears were placed in the fetal femoral artery and vein, and in the fetal artery. All incisions were closed and catheters were tunnelled subcutaneously to the maternal flank and stored in a protective pouch. Immedi~telyfollowing the surgical procedure, catheters were filled with 4 IU/mL heparin in saline solution. Penicillin G (2 000 800 U) and gentamicin ( 120 mg) were administered intravenously to the ewe. At the same time, the fetus received penicillin G ( 1 8CK) 0 0 %I) and gentamicin (40 mg) intravenously. On the day of study, all ewes were transported in a cart to a quiet study room with a companion sheep, and left for at least B h prior to study. They had free access to food and water during the procedure. In the maternal infusion studies, a 9.5% v/v solution of ethanol in 5% w/v dextrose in water was infused via the maternal femoral vein at a rate of 1.2 g/kg total body weight over 2 h. Simultaneous blood samples were obtained from the maternal ( I .O mL) and fetal (0.75 mL) femoral arteries at 30-min intervals. starting just prior to infusion and continuing for 5-7 h after the end of infusion. At each sampling time, the heparinized saline was removed from the catheters and a volume of blood approximately equal to twice the catheter dead space was removed prior to sampling and reinfused after sampling. The samples were placed in tubes containing potassium oxalate and sodium fluoride, and stored on ice. Within 2 h, the samples were centrifuged. The plasma was separated and stored at -20°G. Additional samples were drawn into heparinized syringes at l-h intervals for immediate blood gas analysis using a Corning pH/BBood Gas instrument model 16512 (Canlab Laboratories, Winnipeg, Manitoba). Maternal and

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CAN. J . PHYSBOL. PHAKMACOL. VOL. 62. 1984

@

MATERNAL

A

FETAL

@

MATERNAL


FETAL I

2

0

FIG. 1. Representative plasnaa ethanol conceaitration versus time curves from maternal and fetal blood sananplcs after maternal infusion of ethanol, H.2 g/kg total body weight, over 2 & (9.5% v/v ethanol in 5 % w/v dextrose solution at 15 mL/kg over 2 h). fetal heart rate and arterial blood pressure were monitored with Stathanm transducers connected to indwelling catheters, and recorded on a Hewlett Packard model 8824C Dynograpk strip chart recorder (Hewlett Packard, Mississauga, Ontario). At the end of thc experiment, ewes were anesthetized with sodium pentothal and sacrificed by intravenous administration of saturated potassium chloride solution, to allow for verification of catheter placement. To assess the transfcr of ethanol from the fetus to the mother, ethanol was administered in three different doses directly to the fetus as described below. In one fetal infusion study, the ethanol infusion, as described above, was administered via the fetal femoral vein at 0.4 g/kg maternal body weight over 1 h. Two successive fetal infusion studies used infusion rates of 0.5 g/kg over 4 h and 0.3 g/kg over 3.5 h. Blood samples in these latter studies were obtained as in the maternal infusion studies, starting just prior to the infusion, and continuing for 2-3 h after termination of the infusion. Blood gas analysis, heart rate. and blood pressure were determined as in the maternal infusion studies. Plasma ethanol was measured to avoid inter- and intra-animal variation owing to differences or changes in henlatocrit (Payne ef wl. 19648). Plasma ethanol concentrations were determined by gas-liquid chromatography with a Hewlett Packard model 402 instrument, using a flame ionization detector and a Poropak Q/W column (Solon et al. 1972). Operating parameters included a column and injector port temperature of 150°C. and a detector temperature of 250°C. 1Propanol(0.292 v/v) was used as the internal standard. The assay was sensitive to 0.01 g/L plasma ethanol. This method is essentially the same as that previously reported by us (Rangno st ad. 1981). D a m irnadysis Data for the calibration curve for ethanol quantitation, and the elimination rates for ethanol from maternal and fetal circulation were analyzed by least squares Binear regression analysis followed by analysis of variance to assess goodness of fit (Goldstein 1964). The apparent volunae of distribution (&6) was estimated by dividing the total ethanol dose by the initial concentration (COB.The initial concentration was determined by extrapolating the peak concentration to zero time, correcting for the elimination of ethanol during that time interval for the animal under investigation. Plasma clearance of ethanol was determined as the slope of the pseudolinear portion of the plasma ethanol concentration versus time curve by the method sf linear least squares regression. The upper distribution phase was excluded from these calculations. All data are presented as means f standard emor. The minimum level for a significant difference is p 5 0.05.

Results Figure I is a representative plasma ethanol concentration-

TIIb4E (hours)

4

FIG. 2. Representative plasma ethanol concentration versus time curves from maternal and fctal blood samples after fetal infusion of ethanol, 0.5 g/kg maternal body weight, over 4 h (9.5% v/v ethanol in 5% w/v dextrose solution at L .53 rnL.Bag-'. h - i over 4 h). TABLEI . Apparent plasma ethanol clearance rates in pregnant sheep after maternal or fetal infusion of 0.3 - 1.2 g/kg doses Apparent ethanol clearance (mg*L ' - h - ' ) Infusion site

Maternal

Maternal Fetal

197? 10(7) %$0+1 l(3)

NOTE: Values in parentheses experiments.

Fetal

203 L5(7) 197(1) are the number of

time curve from the matemal infusion studies. A total dose of 1.2 g/kg ethanol resulted in peak maternal concentrations at 2 h of 1.8 + 8.1 g/L (range, 1.5-2.5 g/L; n = 5). Fetal peak concentrations, also at 2 h , were 1.9 s 0. I g/L (range, 1.62.1 g/L; n = 5). Elanring infusion, fetal concentrations were slightly lower than maternal ethanol concentrations. In four of five studies, fetal concentrations were higher than maternal ethanol concentrations at most times after the dose. However, these differences were not significant. A representative plasma concentration-time curve from the fetal infusion studies is shown in Fig. 2. Fetal infusion sf 0.5 g/kg total body weight over 4 h resulted in peak matemal and fetal ethanol concentrations of 0.3 and I .2 g/L, respectively, at the end of the infusion. Fetal infusion of 0.6 g/kg over I h resulted in fetal death 5 min after the end of infusion. Peak fetal and maternal plasma ethanol concentrations at 1 h were 4.7 and I .2 g/L, respectively. A fourfold difference in maternal and fetal peak concentrations was observed in both fetal infusion experiments. This difference was minimized in a third experiment using a lower infusion rate. The fetal infusion of 0.3 g/kg over 3.5 h resulted in a peak maternal plasma ethanol concentration of 0.4 g/L and a peak fetal concentration of 0-5 g/L at the end of infusion. The apparent plasma clearance rates are presented in Table 1. They were similar regardless of whether the infusion was to the mother or fetus. &Id was estimated from the maternal infusion data as 0.61 + 8.04 L/kg (range, 0.51-0.69 L/kg; a8 = 5 ) . Selected data from the concurrent phamacodynamic assess-

CUMMlNG ET AL.

TABLE2. Pharmacodynamic assessment s f the cardiovascular system from sevcn pregnant sheep receiving ethanol by maternal infusion. Data are presented as means + SE Control


Heart rate (beats/min) Mean arterial blood pressure (mmHg)

Hematocrit (%)

End of infusion

End of experiment

P

M F

11128 14825

126+ 10 l(i4+12

12828 15526

0.393 1.00

M F

9722 6323

91 + 5 5324

98 +- 5 50+5

0.089

M F

2924 35+2

28 2 2 3323

275 8 3122

1 .OO 1 .OO

1.MI

NOTE:M . maternal; F, fetal.

TABLE3. Pharmacodynamic assessment of the cardiovascular system from three pregnant sheep receiving ethanol by fetal infusion. Data arc presented as means t SE

-

Hear%rate (bcats/min) Mean arterial blood pressure (mmHg)

Control

End of infusion

M F

12727 16729

123 3 1131-27

M F

8225 4022

57+ 10

+_

8426

P 1 .OO

0.138

1.00 1 .W

NOTE:M , maternal; F, fetal.

ment of cardiovascular parameters are shown in Table 2 for the maternal infusion studies and in Table 3 for the fetal infusion experiments. Data for the end of the experiment after fetal ethanol infusion are not shown, owing to the different time course for each of the doses. Control values were similar for both maternal and fetal infusions. Correlation analysis of plasma ethanol concentration with all of the cardiovascular pharmacodynamic data demonstrated the following weak but statistically significant associations. In the maternal infusion studies, maternal heart rate varied between 96 and 156 beats per minute and increased with maternal ethanol concentration (F1,54= 8.72; p < 0.01; r = 0.37). Fetal heart rate varied between 128 and 228 beats per minute and also increased with fetal plasma ethanol concentraticsn (F,.,, = 5.89; p < 0.05; r = 8.33). For the fetal infusion studies, fetal heart rate varied between 60 and 220 beats per minute and was inversely related to fetal ethanol concentration (FL,26 = 15.81; p < 0.081; r =

-0.6 1). Maternal mean arterial blood pressure varied between 64 and 102 mrnHg (1 mmHg = 133.322 Pa) and increased with maternal plasma ethanol concentration ( F 1, 3 , = 4.9 1 ;g < 0.05; r = 0.37). None of the other parameters monitored during these studies showed consistent changes with time or treatment including maternal and fetal pH, Pco2, and Po2.

Discussion Peak maternal ethanol concentrations in our study were similar to those of Fuchs ~t al. (1967) far the prevention of premature labour in humans. No differences between maternal and fetal peak ethanol concentrations were noted. Dilts (1970) and Rose el crl. (198 1) reported peak maternal ethanol concentrations to be higher than fetal concentrations. Rose et al. (1981) used a higher infusion rate. Others reported no differences (Mann et al. 1975; Ayromlooi et a / . 1979; Cook ee a&. 1981;Kirkpatrick et a&.1976; Ng et a&.1982). During infusion, fetal ethanol concentrations increased at a slower rate than maternal concentrations. This delay may be attributed to general hemodynamic mechanisms of the placental circulation (Shapiro et al. 1967). However, the difference is small, indicating that rapid placental transfer of ethanol must occur. Similar findings to ours were reported by Dilts ( 1970), Rose et a&. (19811, and Ng et al. (19821, but Cook el al. (1981) and Ayromlooi et al. (1979) found no difference. The observation that fetal ethanol concentrations exceed maternal concentrations after the end of infusion is supported by previous studies (Mann et al. 1975; Rose et al. 1981). These findings are consistent with observations made in human fetuses and newborns where ethanol elimination is much slower than in adults (Idanpaan-Heikkula et al. 1972; Wagner et a&.1970; Seppala et al. 1971). Since ethanol is a relatively small, weakly polar molecule, rapid transfer across the placenta is expected. Different characteristics between maternal-fetal and fetal-maternal exchange is not anticipated. However, infusion of ethanol into the fetus at the same rate as given in the maternal infusion studies resulted in a fourfold difference in maternal and fetal peak ethanol concentrations. This difference may represent limita-

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CAN. J. PHYSIOL. PHARMACOL. VOI.. 62, I584

tions of placental blood flow resulting in impaired transfer to the maternal circulation. Maternal and fetal plasma ethanol clearance rates were similar. This correlates well with the findings of Cook et al. (1981) who determined maternal ethanol clearance to be 204 mg L-' h-' and fetal clearance to be 205 mg L-' h-' 'However, this is not in agreement with Rose et ak. (198 11, who reported maternal and fetal clearance rates of 400 and 100 mg * L-' h- ' . respectively. Ng es a / . (1982) calculated maternal and fetal clearance rates to be similar, but lower than in our study, 145 and 143 mg * L ' h ', respectively. In our experiments, maternal and fetal clearance rates were siinilar regardless of whether infusion was to the mother or fetus. The increase in maternal heart rate in our study with ethanol infusion was also observed by Cook et al. (1981) and Rose et al. (198 I), whereas others (Ayromlooi et aE. 1979; Mann et a&. 1975; Ng et aE. 1982) found no change. The cardiostimulatory action of ethanol may be due to several inechanisms. Acetaldehyde stinaulation of the sinus node (James and Bear 19671, decreased total peripheral vascular resistance (Stein et al. 1963), direct myocardial effects (Kirkpatrick et al. B 9761, and indirect catecholamine release (Kirkpatrick et al. 1976) have been postulated. Fetal tachycardia has also been reported (Mann st ale 1975; Ayromlooi et al. 1979; Cook et al. 1981), which is in agreement with our findings. However, the fetal bradycardia we observed in our fetal infusion studies has not previously .been demonstrated. Kirkpatrick st al. (1976) reported a significant decrease in fetal cardiac contractility associated with maternal ethanol intake. During maternal ethanol infusion, the increases in maternal and fetal heart rates may be due to catecholamine release by the mother. In our fetal infusion studies, the decrease in fetal heart rate was not accompanled by changes in maternal heart rate. The mechanism for the decrease in fetal heart rate is not readily apparent; however, it is believed to be independent of maternal influences. The negative chronotropic action of ethanol on the fetal heart rate might adversely affect cardiovascular adaptation at birth in intoxicated neonates. This study confirms earlier observations that maternal ethanol infusion does not affect maternal (Ng et al. 1982; Ayromlooi st a / . 1979; Cook et al. 1981; Mann et ak. 1975) or fetal (Ng et wl. 1982; Rose et al. 1981; Cook el ul. 1981; Kirkpatrick et al. 1976) blood pressure. Ayromlooi et a1. (1979) reported fetal hypertension during infusion. and Mann et ul. (1975) noted fetal hypotension. However, in the latter study, the use of an acute preparation, in which the fetus is exteriorized, may explain this observation. No change in fetal blood pressure was observed in our fetal infusion studies, but an unexplained increase in maternal blood pressure was noted. We observed no changes in maternal or fetal blood gas parameters in our studies, which is in agreement with others (Dilts 1970; Kirkpatrick et al. 1976; Cook et al. 1981). Ayromlooi et al. (1979) reported an increase in fetal Po,. and suggested that an ethanol-induced increase in uterine blood flow improved fetal oxygenation. The fetal acidosis reported by Mann et al. (1975) may be attributed to the acute preparation, as well as the higher peak maternal ethanol concentration of 2.3 g/&. Arterial blood gas parameters may not accurately reflect major alterations in fetal cardiovascular status (Kirkpatrick et al. 1976). Newborns delivered during or after unsuccessful attempts to inhibit premature labour with ethanol could be expected to have a higher incidence of neonatal depression.

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a

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In conclusion, ethanol is rapidly transferred from the maternal to fetal circulation when it is administered to the mother during pregnancy. On the other hand, the ability of the fetus to excrete or metabolize a large dose of alcohol administered directly to it is impaired. The opposite effects on fetal heart rate when ethanol is administered directly to the fetus suggests that further pharmacokinetic and pharnaacodynamic studies of ethanol in the neonate are needed to assess potential adverse effects related to prolonged exposure to ethanol when the fetus is separated from its intrauterine protective environment at birth.

Acknowledgements This project was supported by grants from the Children's Hospital of Winnipeg Research Foundation and the Canadian Foundation for the Advancement of Clinical Pharmacology. We thank Mr. W. Pucci, Mr. K. Gregory, and Ms. M. Cumming for their excellent technical assistance. AYROML~XII, J., M. T ~ B I AP. S , BERG, and D. DESIDERIO. 1979. Effects ~f ethanol on the circulation and acid-base balance of pregnant sheep. Obstet. Gynecol. (NY). 54: 624 - 630. COOK,P. S., R. M. ABRAMS. M. NOTELOVITZ,and J. E. FRISINGER. 1981. Effect of ethyl alcohol on maternal and fctal acid-base balance and cardiovascular status in chronic sheep preparations. Br. 9 . Obstct. Gynaecol. 88: 188- 194. DILTS,P. V., JR. 1970. Placental transfer of ethanol. Am. J. Obstet. Gynecol. 107: 1 195- 1198. FUCMS, F.. A-R.Fu~HS, V. F. POBLETE, and A. RISK. 1967. Effect of alcohol on threatened premature labor. Am. J. Obstet . Gynecol. 99: 627-636. GOLDSTEIN, A. 9964. Biostatistics: an introductory tcxt. Macmillan Publishing Co., New York. pp. 63-69. 1980. Alcohol, smoking and the HARLAP. S . , and P. N. SHEONO. incidence of spontaneous abortions in the first and second trimester. Lancet, 1: 173- 176. IDANPAAN-HEIKKULA, J., J. JOUPPILA, M. K. AKERBEOM, R. ISOAHO. E. KAUPILLA, and M. KOHVISTO. 1972. Elimination and metabolic effects of ethanol in mother, fetus and newborn infant. Am. J. Obstet. Gynecol. 882: 387 -393. JAMES,T. N., and E. S. BEAR.1967. Effects of ethanol and acetaldehyde on the heart. Am. Heart J. 74: 243 -255. KIRKPATWICK, S. E., P. T. PITLICK, M. J. HIKCMKLAIJ, and W. F. ~IEDMAN. 1976- Acute effects of maternal ethanol infusion on fetal cardiac performance. Am. J . Obstet, Gynecol. 126: 10341037. KLINE,J., P. SHROU'F, Z. STEIN, M. SUSSER, and D. WARBUK'TON. 1980. Drinking during pregnancy and spontaneous abortion. Lancet, 2: 176- 180. L I ~ L ER., E. 1977. Moderate alcohol use during pregnancy and decreased infant birth weight. Am. 9. Public Health, 67: B 154- 1156. MANN, L. I., A. BHAKTHAVATHSALAN, M. LIU,and P. MAKOWSKI. 1975. Placental transport of alcohol and its effect on maternal and fetal acid- base balance. Am. J. Bbstet. Gynecol. 122: 837 - 844. NG, P. K., M. K. COT~LE, J. M. BAKER, B. JOHNSON,P. VAN MUYDEN, and 6 . R. VAN P E ~ E N 1982. . Ethanol kinetics during pregnancy. Study in ewes and their fetuses. Prog. Neuro-Psychopharmacol. 6: 37 -42. BULLET~E, E. M., H. L. R O S E ~ N., P. WOSMAN, and L. WEINER. B 997. Adverse effects on offspring of maternal alcohol abuse during pregnancy. N . Engl. J. Med. 297: 528-530. PAYNE, J . P., D. W. HILL,and D. G. L. WOOD.1968. Distribution of ethanol between plasma and erythrocytes in whole blood. Nature (London), 217: 963 -964. RANGNO, R. E., J. H. KREEFF, and D. S. SITAR. 1981. Ethanol dose dependent elimination: Michaelis-Menten vs. classical kinetic.


analysis. Br. J . Glin. Pharmacol. 12: 667-673. ROSE, J. C., J . W. STRANDHOY. and P. J. MEIS. 1981. Acute and chronic effects of maternal ethanol administration on the ovine maternal -fetal unit. Prog. Blochem. Fharrnacol, 18: 1 - 14. SEPPALA, M., N . C. R. RAIHA,and V . TAMMINEN. 1971. Ethanol elimination in a mother and her premature twins. Lancet, 1: 1188-1 189. SHAPIRB, N. Z.. T. KIKSCHBAUM, and N. S . ASSALI.1967. Mental exercises in placental transfer. Am. J. Obstet. Gynecol. 97: 130- 137. 1972. Automated SOLON,J . , J . WATKINS,and L. MIKKELSON.

analysis of alcohols in blood. Wewlett Packard Technical Paper No. 50. STEIN,S. W., C. S. LIEUER,C. M. LEEVY,G . K. GHERRICK, and W. H. ABELMANN. 1963. 'The effect of ethanol upon systemic and hepatic blood flow in man. Am. J . Clin. uutr. 13: 68-74, SZETO.H. 1982. Pharrnacokinetics in the wine maternal-fetal unit. Ann. Rev. Pharmacol. 'Foxicol. 22: 22 1 -243. and J . GUERRERO. t 970. Effect of alcohol WAGNER, L., G . WAGNER, on premature newborn infants. Am. J. Obstet. Gynecol. 108:

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