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PubMed1988

Amniotic fluid glycoasparagines in fetal aspartylglycosaminuria.

Midterm amniotic fluid samples from one pregnancy with the fetus affected by aspartylglycosaminuria and from 11 normal pregnancies were analysed for glycoasparagines accumulating in urine in aspartylglycosaminuria. The aspartylglucosamine concentration in the affected pregnancy was about five times higher than in the controls, but the absolute value was very low being only about one-thousandth of that in urine in aspartylglycosaminuria and one-tenth of that in urine samples from normal adults. In total monosaccharide analysis, only galactose content in the affected amniotic fluid was slightly elevated compared to controls, indicating that higher glycoasparagines typical of urine in aspartylglycosaminuria were not accumulated in significant amounts. The data demonstrate that the analysis of glycoasparagines in amniotic fluid is not likely to permit reliable prenatal diagnosis of aspartylglycosaminuria.

Acetylglucosamine↗
PubMed1996

Ultrasonographic measurement of amniotic fluid volume in normal diamniotic twin pregnancies.

OBJECTIVE: Our purpose was to determine the amniotic fluid volume in normal diamniotic twins. STUDY DESIGN: The single amniotic fluid index for both twin members, the maximum depth and width of each twin's largest pocket, were measured every 4 to 6 weeks between 15 and 40 weeks in 91 normal diamniotic twin gestations. The two-diameter pocket in each twin was determined as its largest pocket's depth multiplied by its width. Normal twin gestations were defined as those with <20% birth weight discordance, appropriate for gestational age, no fetal anomalies, delivery at > or = 37 weeks, and normal newborns. Amniotic fluid index values, depths, and two-diameter pockets were stratified into 2-week intervals and transformed into base 10 logarithms because of their nongaussian distributions. The correlations of these measurement with gestational age were evaluated. Their means and 90%, 95%, and 98% confidence intervals were determined. RESULTS: The amniotic fluid index changed significantly with gestational age. However, depths and two-diameter pockets did not. The amniotic fluid index rose from 15 to 24 weeks, plateaued until 36 weeks, and then declined. The 90%, 95%, and 98% confidence intervals for each twin's depth were 2.4 to 7.9, 2.1 to 8.8, and 1.9 to 10 cm, respectively (mean 4.3 cm). These respective confidence intervals for each twin's two-diameter pocket were 8 to 44, 7 to 52, and 5 to 63 cm2 (mean 19 cm2). The amniotic fluid index confidence interval curves were plotted from the log (amniotic fluid index)=0.8276 + 0.01675x-0.0000001900x4, R2=0.78, p=0.002 (where x is gestational age). CONCLUSION: The amniotic fluid volume in normal diamniotic twin pregnancies was established ultrasonographically. Only the amniotic fluid index changed significantly with gestational age. These findings may have significance in the clinical management of twin gestation.

Adolescent↗
PubMed2001

Optimization of cytokine stability in stored amniotic fluid.

OBJECTIVE: Many studies use stored amniotic fluid samples to assay cytokines and other proteins for outcome-based research; however, there is little information on the optimal methods of storage. The objective of our study was to evaluate cytokine stability in amniotic fluid stored at different temperatures both with and without a proteolytic enzyme inhibitor. STUDY DESIGN: Patients undergoing midtrimester genetic amniocentesis for routine indications gave consent for the study. After the sample was centrifuged, the acellular portion of the sample was mixed to homogeneity and aliquoted in 0.5-mL increments and stored for 1 year at 4 degrees C, -20 degrees C, and -80 degrees C with and without the protease inhibitor aprotinin. Enzyme-linked immunoassays for angiogenin, interleukin-6, and vascular endothelial growth factor were performed simultaneously on each aliquot. RESULTS: Thirty samples were assayed for each storage condition. Results were calculated as the percentage of its own sister aliquot stored at -80 degrees C without aprotinin. In all samples, there was a significant relation between storage temperature and cytokine levels, with the lowest levels found at 4 degrees C and the highest at -80 degrees C (angiogenin, P =.004; interleukin-6, P <.001; vascular endothelial growth factor, P =.02). The addition of aprotinin improved stability only for angiogenin at all temperatures (all P <.05). CONCLUSIONS: Degradation of cytokines occurs when amniotic fluid samples are stored for prolonged periods at temperatures greater than -80 degrees C. The addition of a protease inhibitor helps stem the degradation of some cytokines.

Amniotic Fluid↗
PubMed1995

Soluble tumor necrosis factor receptors in maternal plasma and second-trimester amniotic fluid.

OBJECTIVES: We assessed maternal plasma and second-trimester amniotic fluid for levels of the p55 and p75 soluble tumor necrosis factor receptors. STUDY DESIGN: Blood was drawn from 61 healthy pregnant women (group A) before second-trimester genetic amniocentesis, and an aliquot of amniotic fluid was also obtained for this study. An additional blood sample was obtained from 13 of these patients at 36 to 40 weeks' gestation. Twenty-three healthy, nonpregnant women of reproductive age donated blood as a control group (group B). All plasma and amniotic fluid specimens were collectively assayed for the p55 and p75 soluble tumor necrosis factor receptors by specific enzyme-linked immunoassays. Additionally, tumor necrosis factor-alpha concentrations were measured in second-trimester plasma and amniotic fluid of 22 patients in group A and in all 23 of the nonpregnant women. RESULTS: The p55 and p75 soluble tumor necrosis factor receptors were detectable in all plasma samples from both groups of patients. The concentrations of both soluble receptors were significantly higher in second-trimester plasma compared with nonpregnant measurements (p < 0.01), and the plasma concentrations of both soluble receptors increased significantly from the second to third trimester (p < 0.01). The p55 and p75 soluble tumor necrosis factor receptors were also detectable in all amniotic fluid samples. Tumor necrosis factor-alpha was detected in the plasma of 15 of 22 patients in the second trimester but in none of the amniotic fluid samples and in none of the plasma samples from the nonpregnant cohort. CONCLUSIONS: Both the p55 and p75 soluble tumor necrosis factor receptors are physiologic constituents of second-trimester maternal plasma and amniotic fluid. Concentrations are elevated in pregnancy and further increase from the second to third trimester.

Adult↗
PubMed1978

Properties of the activation by pepsin of inactive renin in human amniotic fluid.

1. The renin present in human amniotic fluid was found to have an apparent Mr of 58 000 by gel filtration and is thus bigger than renin in untreated kidney extracts and plasma (Mr approximately 40 000). 2. Treatment with pepsin (40 microgram/ml pH 4.8, 2 h, 22 degrees C) caused a 6-fold increase in activity of this renin species, although Mr was not very different (57 000). 3. Unlike renal renin, renin in human amniotic fluid was not a glycoprotein and behaved similarly on concanavalin A-Sepharose before and after activation by pepsin. 4. Ion-exchange chromatography demonstrated a small change in the ionization properties of human amniotic fluid renin after activation by pepsin. 5. Pepsin-mediated activation resulted in a five-fold increase in V, but only a small decrease in the Km of renin to 39% of normal, so that the increase in activity observed was not due to an increase in the affinity of the enzyme for its substrate. The kinetic data were consistent with the theory of noncompetitive inhibition. 6. The activation of human amniotic fluid renin by pepsin may be caused by a change in the tertiary structure of the molecule subsequent to a proteolytic action that does not remove detectable polypeptide components.

Amniotic Fluid↗
PubMed2005

Successful pregnancy after amniotic fluid embolism: a case report.

BACKGROUND: Amniotic fluid embolism (AFE) has a mortality rate of 60% to 80% and accounts for approximately 10% of all maternal deaths in the United States. Although AFE is thought to be an anaphylactoid reaction, there are few reports of subsequent pregnancy after AFE. CASE: A healthy 29-year-old underwent an uncomplicated planned Caesarean section for her third pregnancy. She had a history of placental abruption with the first pregnancy and amniotic fluid embolism with the second pregnancy, for which she was treated with blood products and recovered fully. CONCLUSION: This case of a 29-year-old woman with successful subsequent pregnancy after amniotic fluid embolism and a limited number of case reports in the literature suggest that AFE is a sporadic event.

Adult↗
PubMed1981

Assessment of fetal maturity in Nigeria by amniotic fluid analysis.

Seven different tests of amniotic fluid have been evaluated for assessment of gestational age. Statistical correlation of the lecithin/sphingomyelin (L/S) ratio with gestational age was positive and significant (P less than 0.001). The Nile blue hydrochloride staining test was very reliable in predicting fetal maturity: in all cases where there was at least 15% of orange-staining cells, the age of the fetus was 37 weeks or more. The reliability of this test was greatly improved when combined with the amniotic fluid L/S ratio, and the result of Clements' "shake test", especially when the creatinine value was also greater than 176 mumol/1. Changes in the levels of amniotic fluid urea, uric acid and total protein were not sufficiently consistent to be of value in assessing fetal maturity. Where facilities for ultrasound are not available, these simple tests can be very helpful in the determination of fetal maturity and in the prevention of accidental delivery of immature fetuses.

Amniotic Fluid↗
PubMed2004

Alteration of the amniotic fluid and neonatal outcome.

Quantitative and qualitative alterations of the amniotic fluid complicate 7% of the pregnancies. Polyhydramnios complicates 1-3% while oligohydramnios involves 3-5% of the pregnancies. The most common causes of polyhydramnios are fetal abnormalities, maternal diabetes and twin pregnancies, but are idiopathic in the 60%. Perinatal mortality has been reported to range between 10-30% while the risk of preterm birth reaches up to 22% in pregnancies complicated by polyhydramnios. The neonatal outcome, in cases where polyhydramnios is due to fetal-neonatal abnormalities, depends on the underlying pathology. Polyhydramnios due to defects in intestinal canalisation in particular, has been correlated to good neonatal prognosis. In our experience no early postoperative deaths occurred in a group of 16 newborns consequtively admitted to our unit in the last two years, with abnormalities of the gastrointestinal tract with need of surgery within the second week of life. Most cases of oligohydramnios are due to premature rupture of membranes, other causes are fetal abnormalities, such as urinary tract malformations, or chromosomopaties and drugs e.g. NSAID's. Oligohydramnios of mild entities is often associated to preterm birth, fetal growth restriction. In some cases of oligohydramnios, neonatal survival is highly conditioned by pulmonary hypoplasia which develops with rates that range between 13 and 21%. Neonatal prognosis is often disastrous in cases with severe oligohydramnios, which however could be improved by amnioinfusion, which restores an amniotic fluid volume sufficient in reducing the adverse environmental effects and in prolonging, where possible, pregnancy. Beside the quantity also the quality of the amniotic fluid may be related to the neonatal outcome. Finding of some inflammatory factors (interleukines) in the amniotic fluid seems to be significantly correlated to periventricular leucomalacia (PVL), cerebral paralysis and long-term neurological abnormalities, both in the preterm and term neonate. Therefore, increase of the cytokines in the amniotic fluid could give information not only of the infection but also regarding the risk of developing neurological sequelae in neonatal period. Diagnosis and therapy for pathologies that alter the amniotic fluid have progressed, however efforts have still to be made in the identification and search for those quantitative-qualitative alterations of the amniotic fluid, for their potential implications on neonatal outcome.

Amniotic Fluid↗
PubMed1975

The karyopyknotic index of amniotic fluid cells and its relationship to oestrogen concentration.

Estimations of karyopyknotic index and amniotic fluid oestrogen concentration were made on 107 specimens of amniotic fluid obtained between the 25th and 42nd weeks of pregnancy. The karyopyknotic index was shown to fall with advancing gestation as the amniotic fluid oestrogen concentration increased. The negative correlation between karyopyknotic index and amniotic fluid oestrogen concentration was highly significant when the fetus was female but was not significant when the fetus was male. Intermediate cells from the gential tract of the female fetus can account for the cytological difference between amniotic fluid from male and female fetuses. The fall in amniotic fluid karyaryopyknotic index towards term which suggests that the fetal vagina responds in the same way as the maternal vaginal epithelium to the circulating hormones and not to the oestrogens in the amniotic fluid.

Amniotic Fluid↗
PubMed2005

Intramembranous absorption rate is unaffected by changes in amniotic fluid composition.

Experiments were performed to determine the effect of amniotic fluid dilution on the rate of intramembranous absorption. Seven fetal sheep at 118 days gestation were instrumented with a shunt between the trachea and esophagus and arterial and venous vascular catheters. In addition, the urachus of the fetal bladder was ligated, and a catheter was placed in the bladder. Ligation of the urachus does not interfere with urine flow into the amnion. After 5 days of recovery, fetuses were randomly assigned to one of two protocols; all fetuses completed both protocols. In the fetuses in the control period, continuous urine flow measurement was begun. In the fetuses assigned to the isovolumic dilution protocol, continuous urine flow measurement was also begun and, in addition, amniotic fluid was continually exchanged with lactated Ringer solution on an isovolumic basis. After 3-4 days, fetal blood pressures and amniotic fluid volumes were determined. Amniotic fluid volumes were determined by drainage. Each fetus was then assigned to the remaining protocol. The presence of the tracheal-esophageal shunt and the ligation of the urachus allowed the rate of intramembranous absorption to be calculated. Isovolumic exchange showed no effect on fetal vascular pressures, blood-gas values, or urine production. We could demonstrate no effect of isovolumic dilution of amniotic fluid on its volume. However, we were able to demonstrate an inverse relationship between amniotic fluid volume and intramembranous absorption (P < 0.02).

Absorption↗
PubMed1998

Predictive value of amniotic fluid volume measurements on perinatal outcome.

Amniotic fluid volumes were measured in 1,659 pregnant women to determine the predictive value of these measurements on perinatal outcome. All cases were evaluated by other tests of fetal well-being. 128 cases were oligohydramniotic, and 1,531 cases were normal. In all cases, several parameters were assayed, e.g. fetal distress, way of delivery, meconium in amniotic fluid, Apgar score, transfer to pediatric clinics and early-late neonatal complications. The results of the perinatal evaluation of oligohydramnios were as follows: assessing fetal distress: specificity 94.2%, sensitivity 18.4%, positive predictive value 35.9%, negative predictive value 86.7% and accuracy 82.8%, and assessing low Apgar score the values were 93.0, 21.3, 95.9 and 89.5%, respectively. As a result, measurement of the amniotic fluid volume is an important parameter predicting perinatal outcome, and its predictive value increases if it is combined with other fetal well-being tests with different end points.

Adolescent↗
PubMed1996

Amniotic fluid index predicts the relief of variable decelerations after amnioinfusion bolus.

OBJECTIVE: Our purpose was to determine whether intrapartum amniotic fluid index before amnioinfusion can be used to predict response to therapeutic amnioinfusion. STUDY DESIGN: Intrapartum patients (n = 85) with repetitive variable decelerations in fetal heart rate that necessitated amnioinfusion (10 ml/min for 60 minutes) underwent determination of amniotic fluid index before and after bolus amnioinfusion. The fetal heart tracing was scored (scorer blinded to amniotic fluid index values) for number and characteristics of variable decelerations before and 1 hour after initiation of amnioinfusion. The amnioinfusion was considered successful if it resulted in a decrease of > or = 50% in total number of variable decelerations or a decrease of > or = 50% in the rate of atypical or severe variable decelerations after administration of the bolus. Spontaneous vaginal births before completion of administration of the bolus (n = 18) were excluded from analysis. The probability of success of amnioinfusion in relation to amniotic fluid index was analyzed with the chi(2) test for progressive sequence. RESULTS: The mean amniotic fluid index before amnioinfusion was 6.2 +/- 3.3 cm. An amniotic fluid index of < or = 5 cm was present in 40% of patients (27/67), and an amniotic fluid index of < or = 8 cm was present in 72% of patients (48/67). The probability of success of amnioinfusion decreased with increasing amniotic fluid index before amnioinfusion (76% [16/21] when initial amniotic fluid index was 0 to 4 cm, 63% [17/27] when initial amniotic fluid index was 4 to 8 cm, 44% [7/16] when initial amniotic fluid index was 8 to 12 cm, and 33% [1/3] when initial amniotic fluid index was > 12 cm, p = 0.03). The incidence of nuchal cords or true umbilical cord knots increased in relation to amniotic fluid index before amnioinfusion. CONCLUSIONS: Amniotic fluid index before amnioinfusion can be used to predict the success of amnioinfusion for relief of variable decelerations in fetal heart rate. Failure of amnioinfusion at a high amniotic fluid index before amnioinfusion may be explained by the increased prevalence of nuchal cords or true knots in the umbilical cord.

Adult↗
PubMed1994

Relationship between amniotic fluid and maternal blood nutrient levels.

To study the relationships between amniotic fluid and maternal blood nutrient concentrations, we obtained amniotic fluid and blood samples simultaneously from 76 pregnant women at around 17 weeks gestation. Folate and vitamin B-12 levels were measured by microbiological assay and radioassay, respectively, and zinc, copper and iron levels by atomic absorption spectrophotometry. Mean concentrations of plasma and red blood cell (RBC) folate and plasma copper of the pregnant women were 38 (+/- 1, SD), 1,501 (+/- 374) nmol/L, and 32.7 (+/- 4.8) mumol/L, respectively, all of which were higher than those of healthy non-pregnant controls (p < 0.001). Mean concentrations of plasma vitamin B-12, zinc and iron levels and RBC zinc were 320 (+/- 130) pmol/L, 12.2 (+/- 2.3), 21.7 (+/- 6.1) and 177 (+/- 30) mumol/L and these were similar to those of non-pregnant controls. Amniotic fluid folate, zinc, copper and iron concentrations were 21 (+/- 13) nmol/L, 1.4 (+/- 0.6), 1.7 (+/- 0.6) and 6.8 (+/- 2.1) mumol/L, respectively, which were significantly lower than plasma levels (p < 0.001). However, this relationship was reversed for vitamin B-12 (650 +/- 420 pmol/L). Significant correlations were found between amniotic fluid and maternal plasma and RBC for folate, and between amniotic fluid and maternal plasma for vitamin B-12 (p < 0.001). No such correlations were observed for zinc, copper and iron. There was no correlation between amniotic fluid and/or blood nutrient concentrations and pregnancy outcome including birth weight of infants.

Adult↗
PubMed1997

Regulation of substances in allantoic and amniotic fluid of the chicken embryo.

Traditionally, the avian allantois has been considered a respiratory organ and a dumping ground for metabolic wastes. We tested the hypothesis that the allantoic fluid is also a depot for free amino acids and related compounds. To gain further insight in the specific role of the allantoic fluid, we included plasma and the amniotic fluid in this study. The work was carried out in 13- and 14-day-old chicken embryos. Using an HPLC-fluorometric technique, 40 of the 41 amino acids and related compounds investigated were detected. The amniotic fluid contained 32 compounds, while plasma and allantoic fluid contained 38 and 39 compounds, respectively. The glucose concentration was determined with a hexokinase technique. It was highest in plasma and lowest in the amniotic fluid. We identified three barriers that hyper- and hyporegulate a number of compounds: (1) a blood/allantois barrier, (2) a blood/amnion barrier, and (3) an allantois/amnion barrier. Compared with plasma and allantoic fluid, the amniotic fluid is a mostly hyporegulated environment.

Amino Acids↗
PubMed1977

Failure of bacterial growth inhibition by amniotic fluid.

The bactericidal properties of amniotic fluid normally protect fetuses from late gestational infections by bacteria. Recently, such infections were found responsible for nearly a third of the perinatal deaths in Addis Ababa, Ethiopia. This prompted an analysis of the antimicrobial activity of amniotic fluid in patients in that city. The antimicrobial activity of fluid from 53 women, collected at term, was measured by a semiquantitative plate-count technique. Only one of the fluid samples was bactericidal, 12 were bacteriostatic, and 40 were noninhibitory to bacterial growth.

Amniotic Fluid↗
PubMed1998

Are the cytokines interleukin-6 and angiogenin stable in frozen amniotic fluid?

OBJECTIVE: To determine the stability of cytokines in frozen stored amniotic fluid samples, we measured angiogenin, a potent inducer of neovascularization and interleukin-6, an inflammatory cytokine, in the same sample of midtrimester amniotic fluid 1 year apart. STUDY DESIGN: In this study paired aliquots of amniotic fluid kept at -70 degrees C were immunoassayed for angiogenin and interleukin-6 at two different time periods 1 year apart. Inclusion criteria were (1) samples with clearly identifiable numbers, (2) no evidence of breaks in sealing of samples, and (3) singleton gestation. Amniotic fluid was immunoassayed for angiogenin and interleukin-6 in July 1995 and 1996. Angiogenin sensitivities were 0.078 and 0.026 ng/ml, interassay coefficients of variation were 3.8% and 4.6%, and intraassay coefficients of variation were 2.7% and 2.9%, respectively, in 1995 and 1996. Interleukin-6 sensitivities were 1.74 and 2.37 pg/ml, interassay coefficients of variation were 8.9% and 2.6%, and intraassay coefficients of variation were 3.5% and 1.9%, respectively, in 1995 and 1996. Statistical analysis included paired t test, Wilcoxon signed-rank test, and regression with p < 0.05 significant. Angiogenin and interleukin-6 values were normalized with natural log transformation for statistical analysis. RESULTS: Paired amniotic fluid samples from 30 patients were immunoassayed from 1993 to 1995. The values of angiogenin were significantly lower in the 1996 assay compared with the 1995 assay (median 12.4 [range 5.6 to 61.3] vs 26.7 [range 13.6 to 159.2] ng/ml, p < 0.001). A significant correlation was found between the change in angiogenin levels and the year of the sample, with older samples having the greatest change in values (r=0.5, p=0.008). The values of interleukin-6 were significantly lower in the 1996 assay compared with the 1995 assay (median 230.8 [range 40.9 to 3711.3] vs 289.2 [range 53.7 to 19100.0] pg/ml, p < 0.001). CONCLUSIONS: Angiogenin and interleukin-6 values in amniotic fluid appear to decrease with time despite optimal freezing conditions. The year of sampling and length of storage should be taken into consideration when evaluating amniotic fluid cytokine levels from stored samples.

Adult↗
PubMed1983

[Secretory immunoglobulin A in the amniotic fluid of healthy pregnant females].

Amniotic fluid levels of secretory immunoglobulin A (S-AgA) were measured by simple radial immunodiffusion according to the method of Mancini using a monospecific antiserum against the human secretory component. 256 samples from healthy pregnant women were examined. Amniotic fluid S-IgA concentration increases significantly during normal pregnancy and shows a loose correlation to the phospholipid level.

Amniotic Fluid↗