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Maternal anesthesia and intrapartum fetal events
ABSTRACTS
Annual meeting-November, 1978 Midwest Society for Pediatric Research
Maternal anesthesia and intrapartum fetal events
involved in this transport have not been previously clarified. In the present study, ~Ca uptake was determined in purified microvillus (MV) plasma membrane vesicles and microsomal (MC) membrane of 12 normal term human placentas. In order to describe the specific localization of uptake events involved in Ca pumping by placental organelles, ~Ca uptake was assessed by filtration technique in incubations containing 50/~M 4:'CaCI~, • 5 mM Na-oxalate or 5 mM +_ Na~ H P O , • 5 mM Mg-ATP • 15 mM azide, in isotonic KC1 and membrane protein. 4~Ca uptake was linear from one- to 10-minute incubation time in both MV and MC membrane fractions and was dependent on membrane protein, ATP, Mg ~+ and pH (pH maximum = 7.0). No accumulation was noted in the absence of Mg-ATP and uptake was enhanced by oxalate and phosphate. While the pH maxima of the enzyme Ca ~+ ATPase (previously thought to be involved in Ca -~+transport) is 8.1, no "active" accumulation was noted at this pH. Accumulation ratios in these vesicles exceeded 20:1 (vesicle/ media). Ethacrynic acid was a potent inhibitor of ~Ca uptake (0.1 to 1 ram). Na azide (15 mM) is a known inhibitor of mitochondrial Ca 2+ uptake, and had no effect on 45Ca uptake. Rates of accumulation at 37 ~ were 1.0 to 2.0 n m o l e / m g / m i n u t e in the Mc fraction and 0.4 to 8. n m o l e / m g / m i n u t e in the MV fraction. This study describes for the first time the characteristics o f A T P dependent 4~Ca accumulation by purified microvillus vesicles and "microsomal" membranes in the human placenta, and suggests the presence of at least two ATP-dependent Ca ~+ Ca movement in the human placenta.
I. Chasnoff,* A. Martin,* M. Fletcher,* and R. Depp* (Introduced by C. Hunt), Chicago, I11. Previous studies have suggested an increased incidence of meconium aspiration in infants delivered with the mother under epidural anesthesia. The relationship of maternal anesthesia to intrapartum events and meconium aspiration was analyzed in 415 consecutive vaginal deliveries performed with no anesthesia or under pudendal block or intermittent lumbar epidural (ILE) anesthesia. Covariance analysis and X-~ tests for independence were used to assess the relationships between anesthesia, blood gases, and meconium after correction for birth weight, gestational age, maternal age, labor and prenatal complications, method of presentation, and correlations among the dependent variables themselves. The frequency of intrauterine meconium passage in the three groups was similar (Table I). However, in infants delivered under ILE there was an increase in the number of fetal monitor abnormalities and, more importantly; a significant increase in acidosis and the incidence of intratracheal meconium found at postpartum sucfioning. The data suggest an association of ILE with perinatal complications,
Mechanisms of calcium uptake in the human placenta: A TP dependent CA accumulation by membrane vesicles
Morbidity and mortality of advanced gestational age
J.A. Whitsett,* D. Lo,* J.P. Bohn,* and R.C. Tsang,
J.C. Callenbaeh* and R.T. Hall, Kansas City, Mo.
Cincinnati, Ohio
Previous published data have indicated that the increased morbidity and mortality of post-term pregnancy are confined to infants with the postmaturity syndrome as defined by Clifford. We performed a retrospective review of 53 post-term infants
Calcium (Ca ~+) is transported against a concentration gradient by the human placenta from mother to fetus. The mechanisms *By invitation. Asterisk indicates the same throughout. Table I Fetal monitor abnormalities
type of anesthesia
None PB ILE
N
69 89 257
10 15 93
14 17 36
Cord p H < 7.2
Intrauterine meconium
Cord Pco, > 60 torr
Tracheal meconium N
N
%
2 7
3 8
5 4
7 5
47
18
55
21
10 20 71
15 23 28
%
4 5
6 6
32
12
PB = Pudendal block; ILE = intermittent lumbar epidural.
156
The Journal o f P E D 1 A T R I C S Vol. 96, No. 1, pp. 156-164
0022-3476/80/010156+09500.90/0 9 1980 The C. V. Mosby Co.
Annual meeting-November, 1978 Midwest Society for Pediatric Research
Maternal anesthesia and intrapartum fetal events
involved in this transport have not been previously clarified. In the present study, ~Ca uptake was determined in purified microvillus (MV) plasma membrane vesicles and microsomal (MC) membrane of 12 normal term human placentas. In order to describe the specific localization of uptake events involved in Ca pumping by placental organelles, ~Ca uptake was assessed by filtration technique in incubations containing 50/~M 4:'CaCI~, • 5 mM Na-oxalate or 5 mM +_ Na~ H P O , • 5 mM Mg-ATP • 15 mM azide, in isotonic KC1 and membrane protein. 4~Ca uptake was linear from one- to 10-minute incubation time in both MV and MC membrane fractions and was dependent on membrane protein, ATP, Mg ~+ and pH (pH maximum = 7.0). No accumulation was noted in the absence of Mg-ATP and uptake was enhanced by oxalate and phosphate. While the pH maxima of the enzyme Ca ~+ ATPase (previously thought to be involved in Ca -~+transport) is 8.1, no "active" accumulation was noted at this pH. Accumulation ratios in these vesicles exceeded 20:1 (vesicle/ media). Ethacrynic acid was a potent inhibitor of ~Ca uptake (0.1 to 1 ram). Na azide (15 mM) is a known inhibitor of mitochondrial Ca 2+ uptake, and had no effect on 45Ca uptake. Rates of accumulation at 37 ~ were 1.0 to 2.0 n m o l e / m g / m i n u t e in the Mc fraction and 0.4 to 8. n m o l e / m g / m i n u t e in the MV fraction. This study describes for the first time the characteristics o f A T P dependent 4~Ca accumulation by purified microvillus vesicles and "microsomal" membranes in the human placenta, and suggests the presence of at least two ATP-dependent Ca ~+ Ca movement in the human placenta.
I. Chasnoff,* A. Martin,* M. Fletcher,* and R. Depp* (Introduced by C. Hunt), Chicago, I11. Previous studies have suggested an increased incidence of meconium aspiration in infants delivered with the mother under epidural anesthesia. The relationship of maternal anesthesia to intrapartum events and meconium aspiration was analyzed in 415 consecutive vaginal deliveries performed with no anesthesia or under pudendal block or intermittent lumbar epidural (ILE) anesthesia. Covariance analysis and X-~ tests for independence were used to assess the relationships between anesthesia, blood gases, and meconium after correction for birth weight, gestational age, maternal age, labor and prenatal complications, method of presentation, and correlations among the dependent variables themselves. The frequency of intrauterine meconium passage in the three groups was similar (Table I). However, in infants delivered under ILE there was an increase in the number of fetal monitor abnormalities and, more importantly; a significant increase in acidosis and the incidence of intratracheal meconium found at postpartum sucfioning. The data suggest an association of ILE with perinatal complications,
Mechanisms of calcium uptake in the human placenta: A TP dependent CA accumulation by membrane vesicles
Morbidity and mortality of advanced gestational age
J.A. Whitsett,* D. Lo,* J.P. Bohn,* and R.C. Tsang,
J.C. Callenbaeh* and R.T. Hall, Kansas City, Mo.
Cincinnati, Ohio
Previous published data have indicated that the increased morbidity and mortality of post-term pregnancy are confined to infants with the postmaturity syndrome as defined by Clifford. We performed a retrospective review of 53 post-term infants
Calcium (Ca ~+) is transported against a concentration gradient by the human placenta from mother to fetus. The mechanisms *By invitation. Asterisk indicates the same throughout. Table I Fetal monitor abnormalities
type of anesthesia
None PB ILE
N
69 89 257
10 15 93
14 17 36
Cord p H < 7.2
Intrauterine meconium
Cord Pco, > 60 torr
Tracheal meconium N
N
%
2 7
3 8
5 4
7 5
47
18
55
21
10 20 71
15 23 28
%
4 5
6 6
32
12
PB = Pudendal block; ILE = intermittent lumbar epidural.
156
The Journal o f P E D 1 A T R I C S Vol. 96, No. 1, pp. 156-164
0022-3476/80/010156+09500.90/0 9 1980 The C. V. Mosby Co.