George H. Nelson

Relationship between amniotic fluid lecithin concentration and respiratory distress syndrome

Abstract Determinations of amniotic fluid lecithin concentration have been made at varying stages of gestation in 139 samples of amniotic fluid. The level increases dramatically neart term. Ninety-nine determinations have been made in samples collected at delivery. Eighty-nine samples were associated with infants who did not develop respiratory distress syndrome (RDS), and 10 were associated with infants who did. The mean amniotic fluid lecithin level at delivery in the control group was 0.226 mg. per cent of lecithin phosphorus while the mean concentration in the RDS group was 0.019 mg. per cent. Three samples associated with infants who died of hyaline membrane disease had the lowest lecithin levels of all samples collected at delivery. Tentatively, an amniotic fluid lecithin concentration of greater than 0.100 mg. per cent of lecithin posphorus is being used in our laboratory as suggestive of fetal pulmonary maturity. This figure is double the highest level obtained to date found in an infant with RDS. Determinations of amniotic fluid lecithin concentration appear to be superior to lecithin/sphingomyelin ratios because rather marked changes in ratios can occur solely because of an increment or decrement in sphingomyelin concentration. Filtering amniotic fluid through ordinary laboratory filter paper removes approximately 90 per cent of the lecithin in samples collected near term.

Amniotic fluid phospholipid patterns in normal and abnormal pregnancies

Abstract Normal human amniotic fluid samples have been quantitated for total lipid, total phospholipid, and individual phospholipid components (lysolecithin, sphingomyelin, lecithin, phosphatidyl serine, phosphatidyl ethanolamine, and a solvent front). Amniotic fluid contains about 60 mg. per cent total lipid and 15 mg. per cent total phospholipid with the most abundant phospholipid present being lecithin. Amniotic fluid from several abnormal pregnancies (prematurity, respiratory distress syndrome, hyaline membrane disease, anencephaly with polyhydramnios) tended to show low total lipid, low total phospholipid, and a decreased percentage of lecithin in the phospholipid fraction. The possible contribution of fetal alveolar fluid to amniotic fluid is discussed. A comparison of the phospholipid patterns of human and lamb amniotic fluid is made.

Defects of lipid metabolism in toxemia of pregnancy

Abstract 1. 1. Phospholipid, total and free cholesterol, triglyceride, and nonesterified fatty acids were determined in maternal serum, fetal serum, and placental tissue obtained at delivery. Total lipid and water contents were also determined on the placentas. 2. 2. Normal pregnant patients (12) were compared to toxemic patients (10). The toxemic group consisted of 4 eclamptic and 6 severe pre-eclamptic patients. 3. 3. The only significant difference between the two groups was the triglyceride content of the placenta, which is significantly elevated in toxemia. 4. 4. Correlation coefficients were calculated between each lipid fraction in maternal serum and the corresponding measurement in fetal serum to see if high and low values in maternal serum corresponded to high and low values in fetal serum. No significant correlations were obtained. This suggests that simple diffusion of lipid fractions from maternal serum to fetal serum does not occur. 5. 5. Significant positive correlations between the free cholesterol content and the phospholipid content were obtained in maternal serum, fetal serum, and placental tissue in control patients. In the toxemic patients, only in maternal serum was a significant correlation obtained. 6. 6. Significant positive correlations between the total cholesterol content and the phospholipid content were obtained in maternal serum and fetal serum in control patients. Toxemic patients showed a significant correlation only in maternal serum. 7. 7. In normal pregnancy certain factors are responsible for the positive relationship between cholesterol and phospholipid levels in fetal serum and placentas. In toxemia of pregnancy these factors are altered.

Evaluation of pretreatment transvaginal ultrasonography in the management of patients with endometrial carcinoma

Objective: The objective of this study was to evaluate the usefulness of pretreatment assessment with ultrasonography in patients with endometrial carcinoma. Study Design: Fifty patients with endometrial carcinoma diagnosed by endometrial biopsy or curettage were studied before hysterectomy, bilateral salpingo-oophorectomy, and selected lymph node sampling. Ultrasonographic criteria for determination of tumor grade, depth of myometrial invasion, uterine volume, and tumor volume were established. Tumor grade was compared with preoperative and postoperative pathologic diagnoses, depth of invasion was compared with postoperative pathologic evaluation, and uterine volume and tumor volume were compared with postoperative evaluation of tumor grade and depth of invasion. Data were analyzed by χ 2 testing, and, where appropriate, sensitivity, specificity, and accuracy of the ultrasonographic measurements were determined. Results: The following statistically significant correlations (p ≤ 0.05) were found. Ultrasonography predicted tumor grade as accurately as preoperative pathologic evaluation did. Depth of invasion ≤50% or >50% significantly correlated. Uterine volume ≤200 ml predicted ≤50% depth of invasion 28 of 32 times. Uterine volume >500 ml was noted in six cases; five of these had grade 2 or 3 tumor and four had depth of invasion >50%. Tumor volume ≤20 ml predicted a grade 1 tumor in 25 of 39 cases and depth of invasion ≤50% in 34 of 39 cases. Tumor volume ≥20 ml correlated with a grade 2 or 3 tumor in 11 of 11 cases and a depth of invasion >50% in seven of 11 cases. In 25 grade 1 tumors diagnosed postoperatively by pathologic study, none was associated with a tumor volume >20 ml. Conclusion: Pretreatment ultrasonographic measurements should be of value in the management of patients with endometrial carcinoma.

Alterations of plasma free fatty acids and glucose during labor

Abstract Comparisons were made between the maternal blood sugar and FFA levels during the first stage of labor and at delivery. In all patients studied of various parities both blood sugar and FFA levels are higher at delivery than during the first stage of labor. The increments of rise of blood sugar and FFA concentrations are not correlated with the length of labor between the labor sample collection and delivery, the degree of cervical dilatation at the time of labor sample collection, or the length of fast prior to labor sample collection. It appears that the rise in blood sugar and FFA occurs late in labor, possibly exclusively during the second stage of labor, and may possibly be related to catecholamine release during this period.

Correlation between maternal and fetal plasma levels of glucose and free fatty acids

Abstract Correlation coefficients have been determined between the levels of glucose and FFA in maternal and fetal plasma collected at delivery. Significant correlations were obtained between the maternal and fetal glucose levels and the maternal and fetal FFA levels. From the size of the correlation coefficients and the slopes of regression lines it appears that the fetal plasma glucose level at delivery is very strongly dependent upon the maternal level whereas the fetal FFA level at delivery is only slightly dependent upon the maternal level.

Effect of maternal-fetal disorders on lung maturation. I: Diabetes mellitus

Amniotic fluid for fetal lung maturity studies was obtained from 287 healthy and 198 diabetic women. Classes of diabetes were as follows: Class A, 111; Class B, 58; Class C, 13; Class D, 11; Class F, 4; and Class R, 1. The regression lines representing the relationship of amniotic fluid lecithin phosphorus concentration to gestational age at amniocentesis in each of the groups of diabetic patients were not statistically different from those of the control subjects. Each of the diabetic patients was then matched with a control subject of the same race, sex of newborn infant, and gestational age at amniocentesis. The regression lines of the nonhypertensive, hypertensive, and all diabetics were not different from those of their respective matched control subjects. Also there was no difference in the proportion of mature lecithin phosphorus concentrations at different weeks between diabetic and normal women. The absence of a significant influence of diabetes on fetal lung maturation is probably due to improvement in diabetic control resulting in normalization of the fetal metabolic environment.

Placental transfer of epinephrine: I. Maternal-fetal metabolic alterations of glucose and nonesterified fatty acids

Abstract 1. Fifty-five normal obstetric patients in labor were divided into two study groups (44 control patients and 11 experimental patients who received an infusion of epinephrine at delivery). All patients conformed to rigid selection criteria. 2. Maternal and fetal glucose and NEFA levels were compared at delivery. In addition these measurements were carried out in maternal blood prior to the epinephrine infusion. 3. Following maternal epinephrine infusion, maternal glucose and NEFA levels are elevated; however, only fetal glucose is elevated. 4. The elevation of fetal glucose is thought to be due to two factors: (a) transfer of glucose from maternal to fetal blood and (b) transfer of epinephrine from maternal to fetal blood with stimulation of fetal hepatic glycogenolysis. 5. Failure to find increased fetal NEFA is explained as follows: (a) maternal NEFA does not readily cross the placenta into the fetal circulation and (b) fetal adipose tissue is resistant to the lipolytic action of epinephrine. 6. The process of labor and delivery results in a significant rise in maternal glucose and NEFA which is probably due to maternal endogenous catecholamine secretion.

A comparison of oral prostaglandin E2 and intravenous oxytocin for induction of labor in normal and high-risk pregnancies

The efficacy of oral prostaglandin E2 (PGE2) for induction of labor has been compared to that of intravenous oxytocin. There were 49 patients in each series. The over-all success rate with PGE2 is 82 per cent; with oxytocin, 65 per cent. PGE2 is at least as effective as oxytocin regardless of Bishop score or gravidity. There was no difference in the duration of labor in successful inductions with PGE2 or oxytocin. Nausea and diarrhea are more common with PGE2 but in only one case was this severe enough to warrent discontinuing the medication. One case of uterine hypertonus occurred in each series. No serious harmful effects on mother or fetus were noted with PGE2. These data support the concept that oral PGE2 administration is a safe and effective alternative to intravenous oxytocin for induction of labor in normal and high-risk pregnancies.

Effects of Gestational Age, Dexamethasone, and Metopirone on Lecithin Concentration in Fetal Lung Tissue and Amniotic Fluid in Rats and Guinea Pigs

There is a significant increase in acetone-precipitable lecithin (APL) concentration with advancing gestation in fetal lung tissue and amniotic fluid in rats. Measurement of the APL concentration in fetal lung tissue and/or amniotic fluid provides an excellent model for evaluation of fetal lung maturation. The surge of lecithin concentration in amniotic fluid lags behind that in fetal lungs by about 1 day. This supports the concept that fetal lungs are a main contributor to the amniotic fluid lecithin pool. Dexamethasone stimulates the biosynthesis of APL in fetal lungs in rats and guinea pigs. These data support the hypothesis that glucocorticoid treatment in the pregnant woman accelerates fetal lung maturation. Metopirone inhibits the biosynthesis of APL in fetal lungs.