Biomedical subjects

L C Gilstrap

Publications and source records attributed to L C Gilstrap.

At least 55 records · Page 3Linked to original sources

PubMed1991

"Meconiumcrit" and birth asphyxia.

Determination of the percent by volume of the solid component of meconium (the "meconiumcrit") provides a more objective method of characterizing the type of meconium. In a study of 106 women with meconium-stained amniotic fluid, 61 (58%) had thin meconium, 36 (34%) had moderate meconium, and nine (8%) had thick meconium. There was no correlation between the type of meconium and newborn acidemia (umbilical artery pH, less than 7.20)--13%, 19%, and 11%, respectively. None of the newborns with either thin or thick meconium had 1-minute Apgar scores of less than or equal to 3 and only two with moderate meconium had such Apgar scores; none had an Apgar score of less than or equal to 3 at 5 minutes. None of the newborns with thin or moderate meconium had meconium aspiration syndrome, although two of nine infants with thick meconium did have meconium aspiration syndrome. All newborns subsequently did well and left the hospital in good condition. There would appear to be no correlation between the consistency of meconium and recently reported criteria for defining birth asphyxia.

Apgar Score↗

PubMed1991

Is hyperthermia teratogenic in the human?

Maternal hyperthermia during embryogenesis has been postulated to cause a variety of major congenital anomalies in exposed offspring. Although the literature regarding human exposures is not conclusive, studies using animal models support the contention that major structural anomalies may be produced. In the present study, pregnancy outcome of a cohort of women who reported having a temperature of 101 degrees F or higher for 24 hours or more during the first trimester was compared to a control group of women (matched on last menstrual period, parity, and age) who denied having a fever. A statistically significant increased frequency of a specific type of congenital anomaly, abdominal wall defects, was found in offspring whose mothers had sustained high temperatures during embryogenesis. Although an increased risk of this type of congenital anomaly is not consistent with previous epidemiologic studies, similar defects of this organ system have been reported in offspring of pregnant nonhuman primates (monkeys) and rodents (guinea pigs) who experienced hyperthermia during pregnancy.

Adult↗

PubMed1991

Anaerobic coverage for intra-amnionic infection: maternal and perinatal impact.

Although intrapartum antibiotics are beneficial to both the mother and newborn, there is no consensus as to the most efficacious antibiotic regimen in the treatment of intra-amnionic infection, especially with regard to anaerobic coverage. We randomized pregnant women with intra-amnionic infection to receive either dual agent therapy (ampicillin and gentamicin) or triple agent therapy (ampicillin, gentamicin, and clindamycin). The frequency of vaginal and cesarean delivery was similar in both groups. There was no significant difference in the incidence of endometritis between the two groups (10 of 69 versus 5 of 64; p = NS). There were no significant differences in either neonatal morbidity or mortality. The addition of clindamycin to provide anaerobic coverage for intra-amnionic infection does not significantly alter the incidence of endometritis in women delivered by cesarean section, although it may have an impact on women delivering vaginally.

Ampicillin↗

PubMed1991

Intrapartum antibiotic therapy for suspected intraamniotic infection: impact on the fetus and neonate.

Acute chorioamnionitis occurs relatively frequently in pregnancy and may result in significant fetal and neonatal morbidity. Although there is no unanimity of opinion regarding the most efficacious antibiotic regimen for the treatment of this complication, there is a consensus, at least among obstetricians, that maternal treatment may have an impact on neonatal outcome. It appears that the fetus and neonate benefit from "intrauterine" treatment. Virtually all antibiotics cross the placenta, and fortunately most are relatively safe for use during pregnancy.

Anti-Bacterial Agents↗

PubMed1991

Trimethoprim and sulfamethoxazole transfer in the in vitro perfused human cotyledon.

Utilizing the in vitro human placental model, we studied the placental transfer of trimethoprim and sulfamethoxazole. At trimethoprim concentrations of 7.2 micrograms/ml, only 1.4 micrograms/ml was transported across the placenta after 1 h, and at concentrations of 1.0 microgram/ml, one half the usual serum level, only 0.08 microgram/ml was transported across the placenta. Maternal concentrations of sulfamethoxazole of 29.6 and 127.7 micrograms/ml resulted in concentrations of 5.1 and 14.8 micrograms/ml on the fetal side, respectively. Thus, it would appear that trimethoprim is slowly transported across the placenta and in low concentrations whereas sulfamethoxazole readily crosses the placenta. The combination of these drugs is useful for treatment of bacteriuria. It may also prove to be especially useful for Pneumocystis carinii infections in pregnant women with AIDS. With a half-life of 13 h for trimethoprim and 6 h for sulfamethoxazole, the drugs are not likely to achieve toxic levels in the fetal compartment. Thus, it would appear that trimethoprim and sulfamethoxazole may be both efficacious and safe for the treatment of both these infections during pregnancy.

Female↗

PubMed1991

Stress hormones and acid-base status of human fetuses at delivery.

The relationship of plasma concentrations of arginine vasopressin (AVP), ACTH, cortisol, and PRL in the human fetus to mode of delivery and acid-base status has been investigated in 91 term pregnancies consisting of 4 groups based on mode of delivery, type of anesthesia, and use of ephedrine prophylaxis for maternal blood pressure control. Infants delivered vaginally after uncomplicated labors had higher umbilical cord plasma concentrations of AVP, ACTH, and cortisol than infants delivered without labor. Use of ephedrine, an alpha-agonist, during regional anesthesia was associated with elevated plasma AVP and ACTH concentrations compared to those in women receiving general anesthesia. At the time of delivery, 12 infants had acidemia (pH less than 7.20), as judged by pH of umbilical arterial blood. Their plasma AVP, ACTH, and cortisol levels did not differ from those of infants delivered by uncomplicated vaginal delivery, but were greater than those of infants delivered by cesarean section under general anesthesia. Moreover, in infants with acidemia, plasma concentrations of AVP and ACTH were significantly correlated, but PRL levels were unaffected by mode of delivery or acidemia. Elevated umbilical cord plasma concentrations of AVP, ACTH, and cortisol characterize term vaginal deliveries and are associated with intrauterine stress, demonstrating activation of the fetal hypothalamic-pituitary-adrenal axis and suggesting that AVP is important in ACTH release in the human fetus; however, PRL does not appear to be an important stress hormone.

Acid-Base Equilibrium↗

PubMed1991

Uterine contraction pressures achieved in parturients with active phase arrest.

An adequate trial of labor preceding cesarean delivery for arrest of cervical dilatation in the active phase of labor has not been defined precisely. We reviewed the records of 85 consecutive women at term who received oxytocin for induction or augmentation of labor and who subsequently delivered by cesarean for arrest of labor in the active phase. The mean duration of oxytocin infusion was 15 hours for induction of labor and 8.9 hours for augmentation. Thirty-four (92%) of the 37 women who received oxytocin induction and 44 (92%) of the 48 who had oxytocin for augmentation achieved at least 200 Montevideo units of uterine pressure. All 85 newborns were vigorous at birth and had no complications during their stay in the hospital nursery. Evaluation of uterine contraction pressure can provide a quantifiable end point for the management of oxytocin induction or augmentation of labor.

Cesarean Section↗

PubMed1991

Pathologic fetal acidemia.

There is no clearly established umbilical artery pH cutoff to be used for defining pathologic fetal acidemia (ie, the threshold associated with major neonatal morbidity or mortality). Classically, a pH cutoff of less than 7.20 has been used. Our goal was to define this pH cutoff more precisely. There were 3506 term newborns (2500 g or greater) with an umbilical artery pH of less than 7.20; these newborns were divided into five pH groups. Eighty-seven (2.5%) had a pH of less than 7.00, 95 (2.7%) a pH of 7.00-7.04, 290 (8.3%) 7.05-7.09, 798 (22.8%) 7.10-7.14, and 2236 (63.8%) 7.15-7.19. Two-thirds (66.7%) of the newborns with an umbilical artery pH less than 7.00 had a metabolic component in their acidemia, compared with 13.7% or less in all other pH groups. Significantly more (P less than .05) newborns in the less-than-7.00 pH group had low (less than 3) 1- and 5-minute Apgar scores compared with the other four pH groups. In addition, neonatal death was significantly more common (P = .03) in newborns with a pH less than 7.00, and seven (50%) of the 14 deaths occurred in this group. The statistically significant pH cutoff for all seizures was less than 7.05 (P = .004), and for unexplained seizures was less than 7.00 (P = .01). Eight (67%) of the 12 unexplained seizures occurred in this latter pH group. Thus, a more realistic pH cutoff for defining pathologic fetal acidemia would appear to be less than 7.00.

Acidosis↗

PubMed1991

Elective hospitalization in the management of twin pregnancies.

We sought to evaluate the effectiveness of a policy of early elective hospitalization on the outcomes of 522 consecutive twin gestations delivered at our institution between 1983-1987. During the first 2 years (1983-1985), 237 twin pregnancies were delivered with a policy of elective hospitalization when twin pregnancy was diagnosed between 24-32 weeks' gestation. When possible, elective hospitalization started at 24 weeks' gestation. Electively admitted women remained hospitalized until 34 weeks' gestation, at which time they were discharged unless complications developed requiring continued hospitalization. During 1985-1987, 285 women with twin gestations were intentionally managed as outpatients unless intercurrent complications required hospitalization. A total of 211 twin pregnancies was excluded from analysis because the women did not present for prenatal care (19%) or were undiagnosed until delivery (22%). Of the remaining 311 pregnancies available for study, 134 were managed when the elective admission policy prevailed and 177 when this policy was not in effect. Although the elective admission policy did result in a small reduction in the incidence of low birth weight among the 58 pregnancies hospitalized electively (mean [+/- SEM] gestational age at elective hospitalization 27.7 +/- 0.3 weeks) compared with outpatient management, this policy did not result in an improvement in prematurity (32 versus 36%; P greater than .05) or perinatal morbidity as reflected by requirement for neonatal intensive care (12 versus 11%; P greater than .05) and mechanical ventilation (8 versus 9%; P greater than .05). Moreover, perinatal mortality was actually higher in the electively hospitalized pregnancies (8 versus 2%; P = .01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1991

HIV prevalence in pregnant intravenous drug users in Dallas, Texas.

Information available regarding the prevalence of human immunodeficiency virus (HIV) in pregnant women indicates that the primary risk factor for infection is intravenous drug use. At Parkland Memorial Hospital in Dallas, Texas, approximately 4.7% of pregnant women reported using intravenous drugs. The estimated prevalence of HIV infection among pregnant intravenous drug users at this hospital was 3.3%. This is similar to the HIV infection rates reported for nonpregnant parenteral drug-using populations in other areas of the southwestern United States, suggesting that there may be a lower rate of endemic infection in this region of the country.

Female↗

PubMed1990

Failure to recognize fetal alcohol syndrome in newborn infants.

A clinically distinct constellation of major and minor anomalies, termed the fetal alcohol syndrome, occurs among infants whose mothers abuse alcohol during pregnancy. In addition, significantly higher rates of pregnancy complications, including perinatal deaths and fetal growth retardation, occur among these women and their offspring. We studied the medical records of 40 infants born to 38 alcohol abusers and the frequency of characteristics associated with fetal alcohol syndrome. Physical examinations of 6 infants revealed primary features consistent with a diagnosis of fetal alcohol syndrome. Postnatal growth and development were very poor in 17 (50%) of 34 liveborn alcohol-exposed infants. The diagnosis of fetal alcohol syndrome did not appear in the medical records of any of these infants despite the fact that the mothers' obstetric records included a history of alcohol abuse during pregnancy. This finding emphasizes the importance of good communication between obstetric and pediatric medical staff at this hospital, particularly when providing care for pregnant women and newborn infants at high risk for complications due to maternal alcohol or other drug abuse.

Adolescent↗

PubMed1990

Metabolism of cocaine by human placentas: implications for fetal exposure.

To assess placental metabolism of cocaine, placentas were obtained at the time of delivery and the microsomes were extracted by ultracentrifugation within 2 hours. Placental microsomes were cultured with cocaine at physiologic plasma concentrations similar to those of cocaine users (0.75 micrograms/ml). Two control groups were established. In the first group an anticholinesterase was added to the culture to suppress enzyme activity, and in the second cocaine was cultured alone without placental microsomes to obtain baseline spontaneous conversion of the drug. The results indicate that cocaine is biotransformed by the human placenta, presumably by cholinesterase activity. This suggests that the placenta may provide a moderate degree of protection from cocaine-induced morbidity, such as abruptio placentae and fetal growth retardation, by converting cocaine into less active metabolites. These results also have pharmacogenetic implications because cholinesterase activity varies among individuals. Hence placentas that cannot transform the drug may place the conceptus at greater risk of developmental abnormalities.

Biotransformation↗

PubMed1990

Embryofetal effects of pentamidine isethionate administered to pregnant Sprague-Dawley rats.

The effects of pentamidine isethionate on the developing embryo and fetus have not been previously published. Pregnant Sprague-Dawley rats were given various doses of pentamidine during the period of embryogenesis. Animals were killed on days 18 to 20 of pregnancy and their fetuses were removed by hysterectomy. Autopsies were performed on all fetuses. There were significant differences among groups with regard to maternal weight gain and pregnancy resorption. More pregnancy resorptions were noted in the group that received normal human doses (4 mg/kg/day) of pentamidine than in the control group (p less than 0.05). One structural anomaly consisting of unilateral renal agenesis was noted in the 711 fetuses examined. Skeletal survey of fetal rats was unremarkable. Pentamidine was without teratogenic effects in rats when administered in doses similar to those recommended for adult humans; however, it appears to have an embryocidal effect when given in those same doses during embryogenesis.

Abnormalities, Drug-Induced↗

PubMed1990

17 beta-Hydroxysteroid oxidoreductase activity in human maternal and umbilical cord sera.

The specific activity of 17 beta-hydroxysteroid oxidoreductase (17 beta-HSOR) in human umbilical cord arterial serum has been reported to be similar to that of maternal serum and 5- to 15-times higher than that of cord venous serum. Based on these findings, it was proposed that 17 beta-HSOR in cord arterial serum arises from fetal tissue sources other than placenta. In the course of studies of the role of 17 beta-HSOR in the modulation of bioactive estrogen levels in the human fetus, we determined that: (i) the specific activity of 17 beta-HSOR in maternal serum is 2.1- to 55-times higher than that in either umbilical cord venous serum or cord arterial serum; (ii) the specific activity of 17 beta-HSOR in umbilical cord venous and cord arterial sera are similar; (iii) anti-human placental cytosolic 17 beta-HSOR antibody inactivates the 17 beta-HSOR in maternal, umbilical cord arterial, and cord venous sera but not in maternal or fetal erythrocytes; (iv) the specific activity of 17 beta-HSOR in maternal serum (expressed per mg protein) is higher than that in umbilical cord serum and maternal and fetal erythrocytes, and is approximately 700-times lower than that of the placental microsomal enzyme; (v) the preferred cofactor for maternal serum 17 beta-HSOR is NADP+; (vi) 17 beta-HSOR is associated with the high speed supernatant fraction of maternal serum rather than with the particulate fraction; and, (vii) the patterns of binding of [3H]estradiol-17 beta to proteins in maternal and umbilical cord arterial sera and those of 17 beta-HSOR activity, determined in corresponding fractions obtained after sucrose density gradient centrifugation, are approximately coincidental at S20, omega 4.6-5. The findings of higher 17 beta-HSOR levels in maternal serum compared with umbilical cord arterial serum and the inactivation of the cord arterial serum enzyme by an antibody that recognizes human placental cytosolic 17 beta-HSOR is suggestive that 17 beta-HSOR in cord arterial serum is of placental origin.

17-Hydroxysteroid Dehydrogenases↗

PubMed1990

Magnesium sulfate pharmacokinetics: pregnant Capra hircus model.

A comparison of standard clinical regimens for the administration of magnesium sulfate for treatment of preeclampsia was performed in the pregnant goat model. The regimen of intravenous or intramuscular load and intramuscular maintenance championed by Pritchard was found to yield higher maternal serum levels through the first 4 hours of treatment compared with intravenous load with intravenous maintenance therapy (p less than 0.05); however, neither regimen affected the concentration of magnesium ion in the cerebrospinal fluid. Urinary excretion of magnesium and passage into the amniotic fluid were also evaluated for each route of administration and neither accounted for the disparity in serum concentrations noted during the first 4 hours of magnesium therapy.

Animals↗

PubMed1990

Transverse lie.

To assess the impact of transverse lie on fetal and neonatal outcome, 14 mother and infant pairs with transverse lie were matched to 28 pairs with a vertex and 28 with a breech presentation. The control groups were matched for gestational age, route of delivery, type of anesthesia, and presence of labor. Infants in transverse lie were found to have a lower absolute arterial pH (7.21 versus 7.27, p less than 0.05) as well as more frequent severe acidosis (pH less than 7.1, 3 of 14 versus 0 of 56, p less than 0.04). Their birthweight was also less (2798 gm versus 3251 gm, p less than 0.05) and they sustained more birth trauma and long-term residual effects than either the breech (5 of 14 versus 1 of 28, p = 0.01) or vertex control groups (5 of 14 versus 2 of 28, p = 0.03). Based on these results, we recommend active intervention at 38 weeks' gestational age, via external version followed by labor induction, or failing this, cesarean delivery.

Adult↗

PubMed1990

Alpha-thalassemia: prenatal diagnosis and neonatal implications.

Homozygous alpha-thalassemia major, or Bart's hemoglobinopathy, is the most common etiology of nonimmune hydrops in those of Oriental descent. The prenatal diagnosis can now be made utilizing DNA hybridization technique from fetal cells obtained by either amniocentesis or chorionic villus sampling. A case is reviewed documenting the utilization of DNA studies in managing patients known or suspected to have a history of alpha-thalassemia major.

Adult↗

PubMed1990

Effects of T's and blues abuse on pregnancy outcome and infant health status.

T's and blues (pentazocine and tripelennamine) abuse during pregnancy has been reported to be associated with adverse maternal and fetal effects. In this study, conducted at Parkland Memorial Hospital in Dallas, Texas, pregnancy outcome and health status of infants born to 23 T's and blues abusers were compared to a group of 100 unexposed women and their infants. Infants born to T's and blues abusers had significantly reduced birthweight, length, head circumference, and an increased frequency of major congenital anomalies (3 of 23), including two congenital cardiac anomalies. However, one of these cardiac anomalies occurred in the offspring of a woman who also reported moderate to heavy daily alcohol use during pregnancy. The other cardiac anomaly occurred in association with in utero anoxia. We therefore surmise that a known teratogen (alcohol) and perinatal complications caused two of the major anomalies, and not the pentazocine-tripelennamine combination per se.

Abnormalities, Drug-Induced↗