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PubMed1991

[Determination of steroid hormones in the amniotic fluid in prenatal genetic diagnosis].

In amniotic fluid from the second trimester of pregnancy levels of total and free testosterone, 17 alpha-hydroxyprogesterone and dehydroepiandrosterone were assessed. The median levels of total testosterone during the 15th to 24th week are 0.82 +/- 0.31 nmol/l in pregnancies with male foetuses and 0.32 +/- 0.11 nmol/l in pregnancies with female foetuses. The levels of free testosterone assessed by calculation from concentrations of SHBG and total testosterone are 0.15 +/- 0.04 for male and 0.05 +/- 0.04 nmol/l for female foetuses. The diagnostic reliability of sex determination of the foetus from the total testosterone concentration in amniotic fluid is 94% and estimation of free testosterone increases it further. The median normal 17 alpha-hydroxyprogesterone levels during the 15th to 23rd week of pregnancy are 8.7 +/- 3.5 nmol/l and do not depend on the sex of the foetus and week of pregnancy. The levels of dehydroepiandrosterone in amniotic fluid from the second trimester of pregnancy are in male foetuses 0.64 +/- 0.33 nmol/l and 0.61 +/- 0.32 nmol/l in female foetuses and do not differ. Assessment of testosterone levels serves as a supplementary method for determination of the sex of the foetus and may play an important part in the prenatal diagnosis of syndromes with agenesis of testicles. Estimation of 17 alpha-hydroxyprogesterone is used in prenatal diagnosis of congenital adrenal hyperplasia, estimation of dehydroepiandrosterone can be used in the prenatal diagnosis of hereditary forms of adrenal hypofunction.

17-alpha-Hydroxyprogesterone↗
PubMed1978

Influence of long-term beta-mimetic therapy on the lecithin content of amniotic fluid.

The lecithin content of 157 amniotic fluid samples taken from 60 patients who had been treated with Fenoterol over a long period of time (longer than 30 mg/daily per os for 14 days; intravenous infusion for longer than 7 days) was calculated thin-layer chromatographically according to Kynast and Saling. These lecithin levels were statistically compared with the levels in a control (Wilcoxon test). It emerged that the lecithin levels in the long-term beta-mimetic therapy group were significantly lower, i.e., from 33/0 to 39/6 (33/0-34/6, p less than 0.05; 35/0-39/6, p less than 0.01). The answer to the question how often levels occur in the long-term group which are below the as critical described level of 3 mg Lec/100 ml amniotic fluid appears to be clinically important. It is shown that values below the critical level from 33/0 to 39/6 are much more frequent in the long-term beta-mimetics therapy group than in the control group. There is no known explanation for this. It was concluded that the application of beta-mimetics in cases of long-term tocolysis should only be discontinued when the lecithin content of the amniotic fluid lies above the critical limit of 3 mg Lec/100 ml.

Administration, Oral↗
PubMed1997

Amniotic fluid leukocytes and leukocyte esterase activity in parturients delivered by caesarean section.

Amniotic fluid specimens from parturients undergoing caesarean delivery were examined for leukocytes and leukocyte esterase activity, as well as for amniotic fluid bacteria and mycoplasmas by cultivation. The aim of this study was to evaluate the intrauterine environment in noninfected parturients and the associations between leukocyte test results, amniotic fluid microbial colonization and postcaesarean endometritis. Samples were obtained by direct aspiration at operation from 289 parturients with no clinical intrauterine infection. Among the total study population, leukocytes were found in 41% of the amniotic fluid samples by Gram staining and in 39% of the samples by the leukocyte esterase activity test. Leukocytes and leukocyte esterase activity were observed significantly more often in the amniotic fluids of parturients undergoing operation after onset of labour or ruptured membranes compared with those operated upon with intact membranes and no labour (p < 0.0001 and p < 0.0001). Of 255 amniotic fluid cultures, microbial colonization was observed in 82 (32%) parturients. Positive results in the leukocyte tests were associated significantly with amniotic fluid microbial colonization among parturients who underwent operation with intact membranes, or who underwent operation after rupture of the membranes and had cervical dilatation of < 5 cm at the operation (Gram stain: p < 0.0001; leukocyte esterase: p < 0.003). If cervical dilatation was > or = 5 cm, no such association was observed. In the population studied, endometritis developed in 2% and 4% of the parturients with positive test results. Thus, neither the presence of leukocytes nor detected leukocyte esterase activity were predictive of subsequent postoperative endometritis. In the detection of amniotic fluid microbial colonization, the tests functioned best in non-laboring parturients with intact membranes and in those operated on at the early stage of labour.

Adult↗
PubMed1984

[Significance of hormones in the amniotic fluid. 1. Insulin and C-peptide].

Samples of amniotic fluid of 275 healthy women were used to establish a standard profile of amniotic fluid insulin and C-peptide concentrations versus gestational age. The reasons for amniocentesis were: exclusion of chromosomal defects, rhesus immunisation, and determination of the L/S ratio. The concentrations of both peptides which were measured in the amniotic fluid in diabetics were compared with the normal profile. We found that long-term blood glucose control as estimated by the concentration of glycosylated haemoglobins in maternal blood is not well correlated with amniotic fluid insulin or C-peptide, respectively. In a few cases with poor metabolic control, we found normal insulin values, and vice versa. Since elevated insulin and C-Peptide levels in amniotic fluid correlate well with diabetic foetopathy, we conclude that measurement of both peptides provides a useful parameter in the management of a diabetic pregnancy.

Amniocentesis↗
PubMed1983

Disposition of ethanol in human maternal venous blood and amniotic fluid.

The disposition of ethanol and acetaldehyde in maternal venous blood and amniotic fluid was studied over 3.5 hours following the ingestion of 0.3 gm/kg of ethanol by six healthy pregnant women at 16 to 18 weeks' gestation. There was a time lag in the appearance of ethanol in amniotic fluid compared with its appearance in maternal venous blood. The maximum maternal venous blood ethanol concentration was twice the maximum amniotic fluid ethanol concentration and occurred at an earlier time. At 3.5 hours, ethanol was present in amniotic fluid, whereas there was virtually no measurable ethanol in maternal venous blood. The rate of ethanol elimination from amniotic fluid was about half the elimination rate from maternal venous blood. Acetaldehyde was present in the maternal venous blood of four subjects, and the maximum acetaldehyde concentration occurred at about the same time as the maximum maternal venous blood ethanol concentration. Acetaldehyde was found in the amniotic fluid of one of these four subjects, and the acetaldehyde concentration was greater in amniotic fluid than in maternal venous blood. It is proposed that the amniotic fluid may act as a reservoir for ethanol following maternal ingestion such that the fetus would be exposed to ethanol for a longer time period than would be predicted by the maternal venous blood ethanol concentration.

Acetaldehyde↗
PubMed1990

Detection of immunoregulatory lipid-like factors in human amniotic fluid.

The immunosuppressive activity of amniotic fluid (AF) is extensively documented in the mouse. Although this property is due in part to the presence of alpha-fetoprotein (alpha-FP), other immunosuppressive factors are suspected. In this article, we demonstrate that human amniotic fluid lipid extract (AFLE) is inhibitory of, although not cytotoxic to, PHA-activated human lymphocytes, of mouse bone marrow cells, and of different established cell lines of human and mouse source. This effect is shown to be reversible. Under preparative thin layer chromatography (TLC) using chloroform:methanol:water (60:38:8) as solvents, the activity of AFLE migrates to two peaks of inhibition with Rf values of 0.46-0.62 and 0.84-1, respectively. These lipid-like factors may play a role as a nonspecific immunoregulatory mechanism which prevents maternally mediated immune rejection of the conceptus.

Amniotic Fluid↗
PubMed1983

Antibacterial activity in amniotic fluid from west virginia women.

Amniotic fluids from women in West Virginia were evaluated for the presence of antibacterial activity by a bioassay technique. 41% of 32 third trimester samples were inhibitory. Evaluation of additional test organisms emphasized differences in susceptibility of various bacterial strains; two isolates of Escherichia coli were found which were more sensitive to the phosphate-sensitive antibacterial system of amniotic fluid than in the initial test organism. The stated prevalence of inhibition may therefore be considered a conservative estimate.

Amniotic Fluid↗
PubMed1976

Fetal lung lecithin metabolism and the amniotic fluid L/S ratio in rhesus monkey gestations.

The amniotic fluid lecithin/sphingomyelin (L/S) ratio in normal rhesus monkey pregnancies exhibits a distribution through the latter half of gestation similar to that seen in human pregnancies. Changes in the synthesis and concentration of lecithin in the fetal lung, measured both in vitro and in vivo, are paralleled by changes in the amniotic fluid L/S ratio. Both the amniotic fluid L/S ratio and fetal lung lecithin concentration increase significantly (p less than 0.001) in the final 10 per cent of rhesus monkey gestation, and there is a significant correlation (p less than 0.001) between these two indices of fetal lung lecithin metabolism. Moreover, the onset of these late gestational changes is temporally related to increased activity of the major pathway of de novo lung lecithin synthesis and to the ability of the preterm rhesus newborn infants to remain free of respiratory symptoms after delivery by cesarean section. We conclude that the amniotic fluid L/S ratio is a valid indicator of fetal pulmonary phospholipid metabolism and, therefore, an accurate index of biochemical pulmonary maturity.

Amniotic Fluid↗
PubMed1977

Studies on human sexual development. IV. Fetal pituitary and serum, and amniotic fluid concentrations of prolactin.

Prolactin concentrations were measured in 161 amniotic fluid specimens from 8-40 weeks fetal age and the levels compared with those observed in 45 fetal and neonatal cord sera and in 42 fetal pituitary specimens. Amniotic fluid prolactin levels rose steeply between 12-16 weeks gestation, and then declined to term; the calculated total amniotic fluid content of prolactin showed a similar pattern, but the peak was later, at about 26 weeks gestation. Amniotic fluid concentrations consistently exceeded fetal serum prolactin levels, even during the last trimester, when fetal serum and pituitary levels were highest. The data are compatible with a fetal origin for amniotic fluid prolactin, but only if one assumes that flux of prolactin out of amniotic fluid compartment is negligible, that the fetal kidney in mid-pregnancy clears prolactin at a rate virtually equal to the glomerular filtration rate, and the fetal pituitary shows secretion characteristics quite different from those of the adult gland.

Amniotic Fluid↗
PubMed1997

[The value of blood sedimentation test in early diagnosis of amniotic fluid embolism].

OBJECTIVE: To explore the value of peripheral blood sedimentation in early diagnosis of amniotic fluid embolism. METHOD: The contents of amniotic fluid were detected with blood sedimentation test in 15 cases of amniotic fluid embolism and 100 cases of normal pregnant women. RESULTS: The contents of amniotic fluid including particles of vernix caseasa, lanugo hair and epithelium cells were found in serum of amniotic fluid embolism cases but not found in cases of normal pregnant women. CONCLUSION: It suggested that the blood sedimentation test would be valuable for early diagnosis of amniotic fluid embolism.

Adult↗
PubMed1981

Relation of glucose to alpha-fetoprotein in amniotic fluid.

A direct relationship between amniotic fluid glucose and alpha-fetoprotein (AFP) has been found between the 16th and 22nd weeks of pregnancy. This relationship is statistically significant (P less than .001) in each of the 6 gestational weeks tested, the coefficients of correlation vary from .74 to .91. The relationship between amniotic fluid AFP and another metabolite, urea nitrogen, was not significant (r = -.34), suggesting that the AFP-glucose relationship was not spurious. Absence of pregnancy-associated macroglobulins in the samples indicates that they were not contaminated by maternal serum. These data reflect an aspect of fetal metabolism or transport that should be investigated more thoroughly.

Amniotic Fluid↗
PubMed1980

[Creatinine in the amniotic fluid].

Creatinine concentration in the amniotic fluid during the latter half of pregnancy was investigated by single determinations in 39 patients and serial determinations in 2 patients. Concentrations of creatinine remained constant or increased very gradually up to approximately 34 weeks, at which point a more abrupt increase apparently took place so that after 37 weeks the level was 1,5 mg. Physiologically, these data lend support to the commonly held theory of fetal urine as an additive source of amniotic fluid. Clinically, they suggest that assay of creatinine might prove useful in estimation of fetal maturity.

Adult↗
PubMed1986

Morphometry of hypoplastic fetal guinea pig lungs following amniotic fluid leak.

Deficient quantity of amniotic fluid causes fetal guinea pig lung hypoplasia. Oligohydramnios that lasts only 5 days in early gestation is sufficient to reduce fetal lung growth significantly. We quantitated lung structural alterations at 50 days gestation (term is 67 days) of fetal guinea pigs whose amniotic fluid was drained on day 45 gestation. The study period spans the late canalicular-early saccular phases of guinea pig lung growth. Compared to littermate controls (n = 4), experimental fetuses (n = 5) have reduced lung:body weight ratio (2.81 +/- 0.16 versus 3.21 +/- 0.20 X 10(-2), p less than 0.01), indicating lung hypoplasia. Lung volume is significantly decreased in the experimental fetuses (1.17 +/- 0.15 versus 1.34 +/- 0.07 ml, p less than 0.05). The proportion of lung containing parenchyma (i.e. developing alveoli and alveolar ducts) is reduced following oligohydramnios (0.83 +/- 0.04 versus 0.90 +/- 0.02, p less than 0.025). The hypoplastic lungs contain fewer saccules (fetal "alveoli") (46 +/- 20 versus 69 +/- 23 X 10(6), p less than 0.1) and the surface area that would be available for gas exchange is decreased (698 +/- 234 versus 974 +/- 80 cm2, p less than 0.05). Lung volume and volume proportion of parenchyma are reduced in the experimental lung and therefore diminished parenchymal elastic tissue is anticipated. However, the total length of parenchymal elastic tissue in the experimental lungs is decreased to a surprising degree and is little more than half the length in control lungs (504 +/- 222 versus 974 +/- 70 m, p less than 0.0025). Such marked reduction in total length suggests that factors other than smaller lung size have contributed to the decrease of elastic tissue in the experimental group. In fact, elastic tissue length per unit volume is significantly reduced (509 +/- 189 versus 809 +/- 115 m/cm3, p less than 0.025) indicating an absolute decrease in parenchymal elastic tissue in the hypoplastic lungs.(ABSTRACT TRUNCATED AT 250 WORDS)

Amniotic Fluid↗
PubMed1981

Prostacyclin-like, and kallikrein activity of amniotic fluid in pre-eclampsia.

Amniotic fluid from patients with pre-eclampsia was compared with samples obtained from normotensive controls with respect to the inhibiting effect on platelet aggregation (PGI2-like activity) and activating effect on the plasma kallikrein assay and Russell's viper venom test. After 39 weeks gestation, amniotic fluid from pre-eclamptic patients showed significantly less PGI2-like activity ( p less than 0.01) and significantly lower kallikrein levels (p less than 0.01) than that from normotensive controls. The study suggests that the biosynthesis and release of PGI2-like activity and kallikrein may be impaired in pre-eclampsia. In view of the association of pre-eclampsia with intravascular clotting, the highly significant reduction of PGI2-like activity seems important and appears to warrant a clinical trial of prostacyclin administration in this disorder.

Amniotic Fluid↗
PubMed1996

Mathematic modeling of human amniotic fluid dynamics.

OBJECTIVE: We sought to develop a model quantifying the relative contributions of fetal swallowing and intramembranous flow to amniotic fluid dynamics during human gestation. We then used the model to simulate the impact of absent swallowing on amniotic fluid volume. STUDY DESIGN: The model was developed with published data for normal human amniotic fluid volume and composition, human fetal urine flow rate and composition (11 to 42 weeks), and extrapolated data from ovine lung fluid production. Fetal swallowing and intramembranous flow were calculated with assumptions that (1) swallowed fluid is isotonic to amniotic fluid, (2) intramembranous flow is free water diffusion, and (3) 50% of lung fluid is swallowed. The model was then applied to simulate absent fetal swallowing and variable (0%, 50%) proportions of swallowed lung fluid were used as a representation of esophageal atresia-tracheal fistula variations. RESULTS: Fetal swallowed volume and intramembranous flow linearly increase until 28 to 30 weeks. Daily swallowed volume then exponentially increases to a maximum of 1006 ml/day at term, whereas intramembranous flow continues on a linear trend to reach 393 ml/day at term. With absent swallowing and variable amounts of lung fluid swallowed (0%, 50%), predicted amniotic fluid volume is similar to normal values through 20 weeks, exceeds the 95% confidence interval for normal amniotic fluid volume at 29 to 30 weeks' gestation (approximately 2000 ml), and then exponentially increases. Predicted amniotic fluid osmolality (280 to 257 mOsm/kg) is slightly lower than actual values although within the clinically normal range. CONCLUSIONS: This model indicates that the normal reduction in amniotic fluid volume beginning at 34 weeks results from the marked increase in swallowed volume during the third trimester. Additionally, this model correlates well with the timing of the initial clinical presentation of polyhydramnios observed in some fetuses with conditions that result in absent or reduced swallowing or gastrointestinal atresia. Modeling of amniotic fluid dynamics can predict normal changes in fetal fluid exchange and may aid in understanding of amniotic fluid imbalances.

Amniotic Fluid↗
PubMed1976

Cholesterol in amniotic fluid, determined by gas chromatography.

Cholesterol was extracted from amniotic fluid, saponified, converted to its trimethylsilyl derivative, and gas chromatographed, with cholesteryl acetate as the internal standard. The method is sufficiently accurate and precise for use with the range of concentrations of cholesterol found in amniotic fluid (5 to 48 mg/litre). Total cholesterol was measured in amniotic fluids collected at different stages of gestation. No significant trend or change was observed nor was cholesterol in the amniotic fluid and the mother's serum correlated at any stage of gestation. Thus we conclude that cholesterol is not a useful indicator of fetal age or maturity. Cholesterol concentrations in amniotic fluid from complicated pregnancies were within the range found for normal pregnancies.

Amniotic Fluid↗
PubMed1984

Isolation of a somatomedin-binding protein from preterm amniotic fluid. Development of a radioimmunoassay.

Amniotic fluid binding protein (AFBP) is a heat and acid stable somatomedin (Sm)-binding protein with a mol wt of 35-40,000 and an isoelectric point of +/- 4.7. It is reactive in RRAs for Sm and inhibits Sm activity in Sm bioassays. AFBP was purified from midgestational human amniotic fluid (AF) using acid-ethanol extraction, Sephadex G-150 chromatography, high speed gel filtration chromatography, and disc gel-electrophoresis. Specific binding activity (microgram equivalents per mg protein) was quantitated by incubation with 125I-insulin-like growth factor II and dextran-coated charcoal separation. Protein recovery was less than 1%. AFBP antiserum was produced by immunizing rabbits with purified AFBP. The antiserum was cleared of human serum albumin antibodies by affinity chromatography. Immunoelectrophoresis of 20x concentrated preterm AF and fetal serum resulted in one precipitin line. AFBP was labeled by the chloramine-T method. The AFBP antiserum specifically bound +/- 35% of added 125I-AFBP at a final dilution of 1:5000. A double antibody RIA was developed. The AFBP level measured by RIA in midgestation AF (n = 30) was 148 +/- 18 (SEM) and in term AF (n = 12) 72 +/- 36 mu geq/ml. Insulin-like growth factor I/Sm-C values (determined by RIA) in the same samples were uniformly very low (less than 0.10 U/ml). When serum was chromatographed on Sephadex G-200 at pH 2.2, AFBP-RIA activity eluted in one peak corresponding to a mol wt of 35-40,000. Highest activity was found in fetal serum (gestational age +/- 20 weeks) and lowest in serum from adults. The development of the AFBP-RIA may contribute to further elucidation of the physiological importance of Sm and the Sm-binding proteins in pre- and postnatal growth.

Adult↗
PubMed1992

First-trimester amniotic fluid and extraembryonic coelomic fluid acetylcholinesterase electrophoresis.

Acetylcholinesterase (AChE) gel electrophoresis was performed on samples of amniotic fluid and extraembryonic coelomic fluid obtained by high resolution transvaginal ultrasound-guided amniocentesis from 38 women between 8 and 12 weeks of pregnancy. AChE was positive in 33 per cent (12/36) of the amniotic fluid samples; the percentage of positive results decreased as gestation advanced. AChE was positive in 32 per cent (9/28) of the extraembryonic coelomic fluid samples. In 81 per cent (21/26) of matched samples, the AChE results were identical in the two fluids. Amniotic fluid and extraembryonic coelomic fluid AChE electrophoresis cannot be used to diagnose neural tube defects prior to 12 weeks of gestation.

Acetylcholinesterase↗