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PubMed1983

Second trimester amniotic fluid acetylcholinesterase quantitation in the prenatal diagnosis of neural tube defects.

Amniotic fluid acetylcholinesterase (AChe) activity was assayed in second trimester amniotic fluids by inhibition of non-specific cholinesterase using lysivane. Of the 196 samples analysed, 146 were from normal pregnancies; 11 (5.6%) from severe open neural tube defects; two from small open spina bifidas; seven from fetal chromosome abnormalities and two from severe skeletal dysplasias. In addition nine amniotic fluids were meconium stained and 19 (9.7%) had varying degrees of blood staining. Acetylcholinesterase values remained relatively constant from 13-21 weeks gestation in normal pregnancies and a cut-off limit of 3.2 U/l was set (mean + 2 SD). Heavily blood stained amniotic fluids were associated with AChe levels on or above the normal cut-off limit. Meconium staining caused a non-significant elevation of AChe. No significant elevation of AChe was demonstrated for fetal chromosome abnormalities, or severe skeletal dysplasias. Anencephaly and severe open spina bifida had significantly elevated AChe levels.

Acetylcholinesterase↗
PubMedDate not supplied

Clinical significance of persistent amniotic fluid leakage after genetic amniocentesis.

Chronic amniotic fluid leakage is a rare complication of genetic amniocentesis. Pregnancy outcomes in two such patients are presented and six previous cases reviewed. Although chorioamnionitis has not been reported, potentially serious complications may occur including an increased risk for pre-term delivery and fetal skeletal deformity. While conservative management of post-amniocentesis amniotic fluid leakage is advocated, patients should be advised of these risks.

Adult↗
PubMed1983

Reversible acid activation of amniotic fluid inactive renin.

1. Inactive renin was isolated from human amniotic fluid by chromatography with DEAE-cellulose, pepstatin-aminobutyl-agarose, octylagarose and Cibacron Blue F3GA columns. 2. Before and after isolation from amniotic fluid, inactive renin could be activated by incubation with pepsin and by dialysis to pH 3.3, and the acid activation could be reversed by subsequent incubation at pH 7.4 and 37 degrees C. 3. Inactive renin was not activated by procedures expected to dissociate renin from an inhibitor. 4. The results suggest a pH-dependent conformational change as the mechanism of reversible acid activation of inactive renin in amniotic fluid. 5. There are chromatographic and activation similarities of inactive renin from human plasma, kidney and amniotic fluid.

Amniotic Fluid↗
PubMed1996

Detection of superoxide dismutase isozymes in normal and X-irradiated chick amniotic fluid by using isoelectric focussing.

Isoelectric focussing of amniotic fluid of chick system over pH gradient of 4-6 revealed presence of 8 superoxide dismutases. The superoxide dismutase (SOD) isozymes were identified as one major isozyme and other seven were minor ones. Higher expression of SOD (major isozyme) with exposure of 1000 R was studied. The isoelectric point (pI) of major SOD isozyme in control (5) differs from radiation exposed samples (5.12). Hence in radiation exposed amniotic fluid showed more pronounced SOD major isozyme, than control amniotic fluid. It is clearly evident that the SOD isozyme with X-irradiation having different isoelectric points, may lead to modification of the amino acid composition and charges of amino acids in the protein structure of SOD. So, the higher SOD isozyme expression has a role in defence action against free radical damage by X-irradiation during embryonic development.

Amniotic Fluid↗
PubMed1988

Amniotic fluid urea nitrogen in the prediction of respiratory distress syndrome.

Amniotic fluid urea nitrogen levels can be used to predict the neonate not at risk for the development of respiratory distress syndrome. A prospective study of 110 pregnancies compared amniotic fluid urea nitrogen concentrations with the lecithin/sphingomyelin ratio and presence of phosphatidylglycerol. After determination of gestational age, amniotic fluid was analyzed for urea nitrogen concentration and an aliquot was sent to the hospital's commercial laboratory for lecithin/sphingomyelin and phosphatidylglycerol measurement. An amniotic fluid urea nitrogen level less than 7.4 mg/dl predicted the presence of neonatal respiratory distress syndrome in 12 of 13 patients independent of gestational age and birth weight. This assay can be performed at the bedside with simple equipment in 70 seconds at approximately one-fortieth the cost of present standard lung maturity studies.

Amniotic Fluid↗
PubMedDate not supplied

Maternal and fetal factors related to abnormal amniotic fluid.

OBJECTIVE: The objective of this study was to identify maternal and infant characteristics related to alteration of amniotic fluid volume at birth. STUDY DESIGN: A series of 27,145 consecutive malformed newborn infants from the Spanish Collaborative Study of Congenital Malformations (ECEMC) was analyzed. From this total, 3.01% were found to have oligohydramnios and 3.69% were found to have polyhydramnios. RESULTS: As expected, renal/urinary tract and lung defects were associated with oligohydramnios, whereas esophageal and intestinal atresias, neural tube defects, and other central nervous system malformations were associated with polyhydramnios. In addition, other defects such as cardiovascular anomalies, hydrocephaly, and microcephaly were also related to abnormalities of amniotic fluid volume. After excluding the defects whose association to oligo- or polyhydramnios is well recognized, we compared the frequency of different variables among them and with infants with a normal volume of amniotic fluid. In comparison with infants with normal amniotic fluid volume, the groups with oligo- and polyhydramnios had lower birth weight, shorter gestational age and umbilical cord, higher parental ages, and a greater frequency of spontaneous abortions. The differences were more marked for weight in newborn infants with oligohydramnios, and for gestational age, umbilical cord length, number of previous pregnancies, and spontaneous abortions in polyhydramnios cases. Placental weight was lower in oligohydramnios cases than in infants with normal amniotic fluid, and higher in polyhydramnios cases. Parental consanguinity and twinning were more frequent in polyhydramnios. Maternal morbidity was higher in both groups with abnormal amniotic fluid volume, especially for acute diseases such as hypertension, diabetes mellitus, and gestational diabetes. Chromosomal aberrations were more frequent in the oligo- and polyhydramnios groups than in cases with a normal volume of amniotic fluid, which supports the suggestion of performing prenatal cytogenetic analysis in any pregnancy complicated by an abnormal volume of amniotic fluid. CONCLUSION: The fact that all of these results are similar in the control group of healthy infants suggests that at least some of the variables associated with abnormal amniotic volume could be considered as causal factors altering the production of fluid.

Birth Weight↗
PubMed1990

Plasminogen activator inhibitors type 1 and type 2 and plasminogen activators in amniotic fluid during pregnancy.

Plasminogen activator inhibitor activity (PAI), PAI-1 and PAI-2 antigen, and other fibrinolytic parameters were evaluated in amniotic fluid during normal pregnancy and compared with that obtained in plasma of pregnant women. The results indicate the presence of both PAI-1 and PAI-2 in amniotic fluid during normal pregnancy. In amniotic fluid, PAI-1 antigen levels increased from 194 +/- 109 ng/ml (first trimester) to 640 +/- 396 ng/ml (third trimester) and PAI-2 antigen levels increased from 72 +/- 57 ng/ml to 173 +/- 97 ng/ml. In contrast, a decrease in tissue-type plasminogen activator (t-PA) antigen level was observed during pregnancy. The PAI-1 levels in amniotic fluid were significantly higher than the PAI-1 levels in plasma of women at a similar gestational age. However, PAI activity, measured using single chain t-PA, was lower in amniotic fluid than in plasma of normal pregnant women. The PAI activity/PAI-1 antigen ratio in amniotic fluid after activation by a denaturing agent increased from 0.003 +/- 0.004 to 0.059 +/- 0.018. These results indicate that high levels of PAI-1 are present in amniotic fluid and suggest that this PAI-1 is present in a latent form that can be reactivated, at least partially, by a denaturing agent.

Amniotic Fluid↗
PubMed1980

Pregnancy specific beta 1-glycoprotein and human chorionic gonadotrophin levels n amniotic fluid and maternal serum in the first half of pregnancy.

Pregnancy-specific beta 1-glycoprotein (PSBG) and chorionic gonadotrophin (HCG) were measured by radioimmunoassay in the amniotic fluid of 99 normal pregnancies, 19 pregnancies of women at risk of having another child with congenital nephrosis and 8 pregnancies in which the fetus had a neural tube defect. Maternal serum PSBG and HCG levels were estimated in 52 normal pregnancies and 15 pregnancies at risk for congenital nephrosis. Both amniotic fluid and maternal serum PSBG levels increased in either compartment after 14th week of pregnancy. There was a positive correlation between maternal serum and amniotic fluid PSBG concentrations (P less than 0.001), between maternal serum and amniotic fluid HCG concentrations (P less than 0.001), and between the amniotic fluid PSBG and HCG levels (P less than 0.05) at a given week of pregnancy (wk 15). On average the maternal serum PSBG level was 20-50 times and the HCG level 2-3 times the amniotic fluid level of normal pregnancies. In cases with a neural tube defect the amniotic fluid PSBG and HCG values were similar to those in normal pregnancy. In congenital nephrosis the amniotic fluid HCG concentration was higher than normal at 15-16 weeks of gestation (P less than 0.05), whereas the amniotic fluid PSBG concentration was normal. Thus, placental pathology in congenital nephrosis appears to be reflected as an increased amniotic fluid concentration of HCG in the second trimester.

Amniotic Fluid↗
PubMed1985

[Amniotic fluid 3,3',5'-triiodothyronine (reverse T3)].

RT3(3,3',5'-triiodothyronine) levels in amniotic fluid and T4(thyroxine), T3(triiodothyronine), rT3 and TSH(thyroid-stimulating hormone) levels in maternal and cord serum were determined simultaneously by RIA. We also determined the activities of the monodeiodination of thyroxine to rT3 in placentas. Amniotic fluid rT3 and cord serum rT3 levels decreased, but T4, T3 and TSH levels increased with advancing gestational age. The activities of the monodeiodination in placentas decreased rapidly from midgestation, preterm to term. In maternal hyperthyroidism, amniotic fluid rT3 levels were markedly elevated. Moreover, there were significant positive correlations between amniotic fluid rT3 and maternal serum rT3 (r = 0.756, p less than 0.001, n = 26) and T4(r = 0.509, p less than 0.01, n = 26) in the normal 3rd trimester. We found significant correlations between amniotic fluid rT3 and fetal thyroid function as well as the activity of the monodeiodination in placenta after 17 weeks' gestation. But we couldn't find any such correlations in the 3rd trimester. These data suggest that the amniotic fluid rT3 in the 3rd trimester was affected by maternal thyroid function as well as fetal thyroid function and the activity of the monodeiodination in placenta.

Amniotic Fluid↗
PubMed1991

Extraction of DNA from amniotic fluid cells for the early prenatal diagnosis of genetic disease.

Ten-ml samples of amniotic fluid were taken from pregnancies being terminated at 8-14 weeks' gestation. DNA was extracted from the amniotic cells by sequential centrifugation and analysed using the polymerase chain reaction (PCR). Fifteen samples were analysed for evidence of maternal contamination using Mfd5 oligonucleotide primers for repeat polymorphisms. Ten amniotic fluid samples were tested for the Delta-F508 deletion characteristic of cystic fibrosis to demonstrate a diagnostic application for the technique. In each case, DNA extracted from fetal tissue from the same pregnancy was included in the controls. In 14 of the 15 cases tested with the Mfd5 primers, both the amniotic fluid DNA and the fetal DNA showed no evidence of contaminating DNA. In one case, neither the amniotic fluid cells nor the fetal cells yielded results. In nine of the ten cases tested with the Delta-F508 primers, the amniotic fluid cell DNA provided accurate information about the genetic status of the fetus; in the tenth, the fetal DNA failed to amplify. The results indicate that adequate DNA can be extracted from amniotic fluid from 8 weeks' gestation onward and these samples are suitable for prenatal diagnosis using PCR.

Adult↗
PubMed2006

Studies of the extraction of bilirubin from human amniotic fluid.

The recovery of unconjugated bilirubin from human amniotic fluid was studied using dichloromethane, chloroform/isopropanol (3:1 vol/vol), and chloroform/ methanol (3:1 vol/vol) extraction of human amniotic fluid that had been supplemented with bilirubin at various concentrations. Results were compared with those obtained with conventional chloroform extraction. Mean recoveries were found to be only 28% for chloroform and 25% for dichloromethane. When the polarity of chloroform was increased by the addition of an alcohol, the mean recovery increased to only 40% for chloroform/isopropanol and 38% for chloroform/ methanol. These results suggest that extraction methods for determination of amniotic fluid "delta OD(450)" (visible spectrophotometric absorbance [optical density] of bilirubin at 450 nm) tend to underestimate the result when compared with the nonextraction (direct-scan) method, on which the Liley Prognostication Chart is based. This finding should be clinically significant, particularly if extraction and direct-scan methods are used to monitor the condition of the same patient.

2-Propanol↗
PubMed1977

Hormones in amniotic fluid.

With increasing use of amniocentesis for high-risk pregnancies, measurement of amniotic fluid hormone levels could prove to be a pratical value. Protein steroid hormones as well as prostaglandins in amniotic fluid are reviewed. The source and entry of each hormone, their concentrations, and their possible physiologic role in pregnancy are discussed. Changes in the level of hormones in amniotic fluid or pregnancies with complications jeopardizing fetal well-being are referred to, and their significance is discussed. Since amniotic fluid is close to the myometrium, changes in some amniotic fluid hormones might be responsible for or associated with the onset of labor.

Amniocentesis↗
PubMed1991

[Semiquantitative determination of the amniotic fluid volume in normal pregnancies].

The amount of amniotic fluid was determined semiquantitatively in 600 pregnancies between the 12th and 41st week of gestation. Pregnancies at risk were excluded. The largest amniotic fluid area was measured sonographically in two dimensions. The mean plus/minus standard deviations are correlated with gestational age. A diagram has been prepared. Our results show good correlation with values from invasive quantitative examinations of amniotic fluid amount. However, our procedure is easy to perform and without hazard for the pregnancy, since it is non-invasive.

Amniotic Fluid↗
PubMed1998

The relationship between amniotic fluid macrophage colony-stimulating factor and fetal growth.

The aim of this study was to clarify whether amniotic fluid macrophage colony-stimulating factor (M-CSF) is related to placental development and fetal growth. Maternal serum and amniotic fluid M-CSF levels were analyzed in 22 pregnant women (seven intrauterine growth retardation (IUGR) complicated and 15 normal pregnancies) at 33-40 weeks' gestation. Amniotic fluid was obtained by transabdominal amniocentesis performed under ultrasonographic guidance. The mean amniotic fluid M-CSF level of the IUGR-complicated pregnancy group (5.0 +/- 1.4 ng/ml) was significantly lower (P < 0.05) than that of the normal pregnancy group (7.4 +/- 1.6 ng/ml). All the IUGR-complicated pregnant women subsequently delivered small-for-gestational-age (SGA) infants with significantly lower placental weights than those of the normal infants. There was no significant correlation between amniotic fluid M-CSF levels and gestational age in the normal pregnancy group. The same scattergram showed the amniotic fluid M-CSF levels of the IUGR-complicated pregnancy group tended to be lower than those of the normal pregnancy group at 33-40 weeks' gestation. The results suggested that amniotic fluid M-CSF was one of the regulators of human placental development and was related to fetal growth.

Adult↗
PubMed2005

[Amniotic fluid: a novel source for tissue engineering].

OBJECTIVE: To investigate the possibility of using amniotic fluid cells as seed cells for tissue engineering. METHODS: Amniotic fluid was obtained by ultrasound-guided amniocentesis performed on pregnant women with a gestational age ranging from 16(th) approximately 23(rd) weeks. The cells isolated from the amniotic fluid were cultured in F10 culture fluid with 10% FBS. Immunocytochemistry was used to examine the standard intermediate filaments. After 3 passages of subculture, the cells were harvested and seeded onto PGA polymer scaffold. The cellular morphology, structure and adhesion with scaffold were evaluated by contrast microscope and scanning electronic microscope. RESULTS: The amniocytes expanded rapidly in culture media. Immunocytochemistry revealed positive signals for vimentin, smooth muscle action (SMA), and pan cytokeratin, and negative signals for desmin. Amniocytes-polymer complex analysis showed confluent cells firmly attached to the scaffold, with no evidence of cell death. CONCLUSION: The expansion potential of amniotic fluid cells is active. They express the characteristics of mesenchymal cells. The cells on PGA polymer scaffold can grow rapidly and maintain its morphological property. So the amniotic fluid may be a practical cell source for tissue engineering.

Actins↗
PubMed1983

[Amniotic fluid circulation with special reference to hydramnios].

The undisturbed circulation of amniotic fluid is the result of an intact cooperation between three compartments: maternal organism, fetus and amniotic cavity. Impairment of one of these compartments can produce a pathological increase of amniotic fluid. This is possible by animal experiment through the way of producing a hypoproteinemia in the maternal organism, comparable with the situation of maternal EPH-gestosis. By increasing the intraamnial osmotic pressure after injection of hyperosmotic solution it is also possible to produce polyhydramnios in the animal experiment. This is corresponding to the clinical situation in maternal diabetes mellitus. In studies of pregnant rabbits, the analysis of ultrastructure of the amniotic epithelium showed some alterations which are compatible with secretory activity of the yolk-sac. The epithelium of the yolk-sac is comparable with the human chorion. The amniotic epithelium has only a function as a semipermeable membrane for the diffusion of amniotic fluid. Morphological examinations of the human placenta and the amniotic sac showed an increase of placental weight in cases of polyhydramnios. There was no increase, however, of the placental surface. Disturbances of circulation in the placental villi were not seen more frequently than in a control group. In cases of polyhydramnios there were more disturbances of villous maturation. The analysis of ultrastructure of the amniotic epithelium and the surface of the umbilical cord showed some possible ways for the increase of amniotic fluid volume.

Amnion↗
PubMed1990

Amniotic fluid insulin concentration as a predictor of obesity.

Longitudinal correlations were obtained between amniotic fluid insulin concentration at 32 to 38 weeks' gestation and anthropometric characteristics at the age of 6 years in 56 children of diabetic mothers. The prospective studies indicated that at the age of 6 years, as at birth, the greatest increase in weight in relation to height (relative obesity) was seen in children who experienced the greatest exposures to insulin in the uterus (as judged by amniotic fluid insulin concentration). Significant correlations between amniotic fluid insulin and relative obesity at the age of 6 years were found after adjustment for maternal obesity and macrosomia at birth. The highest amniotic fluid insulin values are clustered in the subgroup of 14 children who were obviously obese by the age of 6 years. These findings are consistent with the hypothesis that there is an association between anthropometric development and intrauterine metabolism, and suggest that premature and excessive exposure to insulin during gestation may predispose to obesity in childhood. The amniotic fluid insulin concentration may predict this eventuality.

Amniotic Fluid↗
PubMed1978

Surface-active material in human amniotic fluid.

Surface-active fractions similar to the biochemical constituents of the pulmonary surfactant system can be isolated from human amniotic fluid and lung tissue from week 10 of gestation through term. Amniotic fluid yielded 10 mg. per 100 ml. surface-active material at 10 to 28 weeks' gestation and 330 mg. per 100 ml. at term. Fetal lung at 10 weeks of gestation gave 1,233 mg. per 100 ml. and 1,670 mg. per 100 ml. at 4 days after birth. The constituent PC of these surface-active fractions from amniotic fluid and lung contained in excess of 60 per cent palmitoyl residues. PC associated with the surface-active fraction accounted for no more than 15 per cent of the total amniotic fluid concentration of this compound. Minimum surface tensions obtained with these preparations from amniotic fluid ranged from 2.5 dynes per centimeter at 33 weeks to 8.3 dynes per centimeter at 40 weeks. At 14 to 28 weeks, the surface-active fraction from lung gave a minimum surface tension of 18.1 dynes per centimeter and 7.0 dynes per centimeter by 4 days after birth. These findings are consistent with the observation that an increase in the activity or concentration of the fetal lung surfactant system takes place in the last 4 weeks of gestation. Some constituents of this system, or their derivatives which have possibly been altered as a result of biochemical changes, are found in amniotic fluid. We infer that the majority of PC in amniotic fluid is not directly associated with the biochemical constituents of the fetal lung surfactant system.

Amniotic Fluid↗