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PubMed1984

Pyruvate kinase in human amniotic fluid--a new indicator of fetal maturity in late pregnancy.

During the second and third trimesters increasing activities of the glycolytic enzyme pyruvate kinase are to be found in human amniotic fluid. At term (37 to 42 weeks), a very steep rise in amniotic fluid pyruvate kinase can be noticed, which may serve as an additional prenatal indicator of fetal maturity. The presumable main sources of the enzyme in amniotic fluid are the epithelium cells of the skin, the respiratory tract and the amnion. In meconium stained amniotic fluid no pyruvate kinase activity is detectable. Addition of meconium to amniotic fluid samples with previously present pyruvate kinase activity leads to a disappearance of the enzyme activity.

Amniotic Fluid↗
PubMedDate not supplied

False elevation of amniotic fluid enzymes of relevance for prenatal diagnosis: creatine kinase measurement in relation to Duchenne muscular dystrophy.

The creatine kinase activity of amniotic fluid was measured in samples collected at fetoscopy. In our first study, the control sample range was 0.25 IU/l, although four samples had activities of 35-85 IU/l. Elevated values did not correlate with the activities in the fetal or maternal circulations. Electrophoresis revealed the presence of the BB isozyme of creatine kinase rather than just the MM form as expected. This suggested that the source of the elevated enzyme activity was from the myometrium, damaged by insertion of the trocar and cannula. In a further series the first 2 ml of amniotic fluid withdrawn yielded a much higher creatine kinase activity than a second aliquot. A control series of such second samples (first 2 ml discarded) gave an activity range of 0-7 IU/l with no spuriously high values. This compares favourably with a series from single samplings taken by amniocentesis. Normal creatine kinase activities were found in the amniotic fluids from 20 pregnancies at risk of Duchenne muscular dystrophy. We conclude that for accurate measurement of amniotic fluid enzyme activity the first portion withdrawn should be discarded. Amniotic fluid creatine kinase activity is of no value for the prenatal diagnosis of Duchenne muscular dystrophy.

Amniocentesis↗
PubMed2004

Neurogenic cells in human amniotic fluid.

OBJECTIVE: The purpose of this study was to determine whether human amniotic fluid contains cells that harbor the potential to differentiate into neurogenic cells. STUDY DESIGN: Amniotic fluid cells (uncultivated or cultivated in standard or in neurogenic differentiation medium) were analyzed for morphologic neurogenic differentiation and for expression of cluster of differentiation 133 (marker for neuronal stem cells), nestin (neuronal progenitor cells), neurofilament (neurons), the p75 common neurotrophin receptor, the brain-derived neurotrophic factor and neurotrophin-3 and cyclic nucleotide phosphodiesterase (oligodendrocytes). RESULTS: The appearance of neurogenic cells was not detected in uncultivated cells, was sporadic after cultivation in standard medium but strongly increased in neurogenic differentiation medium, and was accompanied by the induction of the expression of the analyzed marker genes. CONCLUSION: For the first time, this study provides evidence that human amniotic fluid contains cells that express markers for neuronal stem and progenitor cells, which harbor the potential to differentiate into neurogenic cells.

AC133 Antigen↗
PubMed2001

[The importance of fibronectin in amniotic fluid in anticipation of premature labor].

We analysed 86 pregnant women where we estimated the fibronectin level in specimens of amniotic fluid. During carrying out the experiment we noted that fibronectin is present in amniotic fluid and can be identified in a quantity mode. We have proved dependence between fibronectin level in amniotic fluid and the period of time from collecting the sample, up to the delivery. Fibronectin level in amniotic fluid doesn't depend on pregnancy duration, preterm rupture of amniotic membranes.

Adult↗
PubMed1978

[Amniotic fluid insulin content as a parameter in assessing fetal condition in diabetic pregnancy (author's transl)].

The average insulin level in the amniotic fluid rises between the 27th and 40th week of pregnancy from 8 muU/ml to 17 muU/ml (n equal to 62). In diabetic pregnancy, the insulin level in the amniotic fluid is in the average elevated to 488%. This indicates oversupply of glucose to the fetus. In the healthy fetus the intercellular apparatus reacts by overproduction of insulin. Part of this insulin reaches the amniotic fluid via the urine. The fetus is in the paradoxical situation of showing simultaneously elevated glucose and insulin levels. The resulting surfeit of insulin is the cause of diabetogenic fetal morbidity. Amniotic fluid insulin levels can be used both to evaluate diabetogenic fetal morbidity, and in order to allow metabolic compensation with insulin to be carried out in accordance with fetal parameters in pregnancy. Examination of the amniotic fluid at bi-weekly intervals from week 27 on thus provides a means of adjusting the metabolic compensation with insulin in the diabetic mother in such a way that diabetogenic fetal morbidity is prevented.

Amniotic Fluid↗
PubMedDate not supplied

Lung surfactant-associated glycoproteins and proteolipids in human amniotic fluids evaluated by dot immunobinding assays.

Dot immunobinding assays for the quantitation of two classes of proteins associated with lung surfactant phospholipids in human amniotic fluid are described. With the use of these assays it was determined that the two classes of surfactant proteins accumulate in the amniotic fluid at the same rate. The concentrations of disaturated phosphatidylcholine and the surfactant-associated proteins are less closely correlated. Centrifugation of amniotic fluids either before or after freezing resulted in a loss ranging from 10 to 35 percent of both surfactant disaturated phosphatidylcholine and proteins depending on the relative centrifugal force used. Preterm amniotic fluids contained significantly less of both surfactant-associated proteins, as well as disaturated phosphatidylcholine, than did term amniotic fluids which suggests that the use of these specific protein markers may enhance the assessment of fetal lung maturity.

Amniotic Fluid↗
PubMed1991

Decidual activation in parturition: examination of amniotic fluid for mediators of the inflammatory response.

The accumulation of bioactive agents (characteristic of an inflammatory-type response) in amniotic fluid is common during term and preterm labor, viz., interleukin-1 beta (IL-1 beta), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-alpha). In addition, prostaglandins, including PGE2, PGF2 alpha, and PGFM, also accumulate in amniotic fluid in some cases of term and preterm labor. From these observations, a number of critical questions arise. Namely, 1) what is the tissue source of origin of these agents?; 2) what are the stimuli that evoke this inflammatory response?; and, 3) are these bioactive agents of inflammation involved in the commencement of labor or else a natural accompaniment of the parturition process? It is reasonable to suspect that the decidua is activated during parturition as the membranes-decidua are exposed after cervical dilation to the vaginal/cervical secretions. Amnion and chorion laeve, in the human, are avascular tissues that produce PGE2 but not PGF2 alpha. Therefore, the accumulation of PGF2 alpha and PGFM in amniotic fluid during labor cannot be attributed to a fetal membrane origin. Moreover, the fetal membranes and decidua do not convert PGE2 to PGF2 alpha. In addition, the fetal membranes do not produce mature, i.e., secreted 17kD IL-1 beta. On the other hand, the decidua does produce PGF2 alpha and PGFM and is stimulated to do so by agents in the vaginal secretions, namely, bacterial endotoxin and IL-1 beta. After the fetal membranes and contiguous decidua are exposed during the time of cervical dilatation, these tissues are acted upon to cause 1) an influx of mononuclear phagocytes into the forebag compartment of the amniotic fluid; 2) to produce PGF2 alpha and PGFM; and 3) to produce cytokines, including IL-1 beta, IL-6, and TNF-alpha. Exposure of the fetal membranes-decidua to bioactive agents in vaginal/cervical secretions will effect an inflammatory response both in vivo and in vitro. We conclude that the accumulation of bioactive agents characteristic of the inflammatory response in amniotic fluid during term and preterm labor is usually an accompaniment of parturition and not its cause.

Amniotic Fluid↗
PubMed1988

Unsaturated B12-binding proteins in amniotic fluid of cystic fibrosis-affected foetus.

The authors hypothesized the possibility of quantitative or qualitative abnormalities of amniotic fluid B12-binding proteins in cystic fibrosis. Seven cystic fibrosis and 59 normal amniotic fluids sampled between 17.5 and 18.5 gestational weeks were studied by radioimmunogel filtration, radioisotope technique, and isoelectric focusing chromatography. In normal amniotic fluid there was an increase of unsaturated B12-binding capacity from 16 to 41 weeks of gestation. There was no statistically significant difference in unsaturated B12-binding capacity, molecular weights and isoelectric points of haptocorrin, transcobalamin 2, and intrinsic factor between cystic fibrosis and normal amniotic fluid. Cobalamin-binding proteins study cannot help in the antenatal diagnosis of cystic fibrosis.

Amniotic Fluid↗
PubMed1979

[Immunoglobulin content of the amniotic fluid and umbilical cord blood].

The content of immunoglobulins IgG, IgA and IgM and total protein in amniotic fluid and foetal serum of healthy pregnant women and of pregnant women with anti-D-antibodies has been determined by the single radial immunodiffusion and biuret method. IgG and IgA was detectable in all samples of amniotic fluid, whereas IgM was only present in 10 p.c. IgA increased in amniotic fluid to the end of pregnancy and it can indicate the maturity of fetus. The pregnant women with anti-D-antibodies have high IgG values in the amniotic fluid with the begin of 34th week of pregnancy.

Amniotic Fluid↗
PubMed1986

[Antiviral activity of the human amniotic fluid and placenta].

Antiviral activity (3-24 IU/ml) was detected in the amniotic fluid of 21 of 25 pregnant women examined (84%) by conventional interferon assay using human amniotic cells (WISH) and vesicular stomatitis virus. The pregnancies were from 16 to 42 weeks gestation without obvious viral infection or other complications. The antiviral substance in the amniotic fluid seems to be interferon alpha, because it was not inactivated by heat (56 degrees C, 30 min) or acid (pH 2.0, 24 hrs.) and it was inactivated by anti-human interferon alpha neutralizing serum. Neither the incidence nor the titer of the activity in amniotic fluid has any relationship with gestational age, age of the pregnant women or parity. Antiviral activity (4-32 IU/10 mg protein/ml) was also detected in the placenta homogenate of 23 of 25 pregnant women examined (92%). The pregnancies were from 7 to 41 weeks of gestation with or without complication. The titer of antiviral activity was relatively high in the placenta of babies with central nervous system anomalies and it was low in the placenta of intrauterine growth retardation pregnancies, compared with normal pregnancies. The activity in the placenta was not inactivated by heat (56 degrees C, 30 min), acid (pH 2.0, 24 hrs.), anti-human interferon alpha neutralizing anti-serum or anti-human interferon beta neutralizing anti-serum.

Amniotic Fluid↗
PubMedDate not supplied

Mosaicism or pseudomosaicism: the problem of hypermodal cells in amniotic fluid cell culture.

A series of 2029 consecutive amniotic fluid specimens studied for prenatal genetic diagnosis were reviewed and reassessed so as to evaluate the frequency and clinical significance of hypermodal cells in amniotic fluid cell cultures. Hypermodal cells were defined as those with more than 46 chromosomes, and were characterized by an additional structurally normal or structurally abnormal chromosome. Of 2029 specimens, 47 (2.31 per cent) contained a total of 167 hypermodal cells. True fetal mosaicism was detected in three cases (0.14 per cent). All had hypermodal cells in more than one culture flask or colony which contained the same aberrant chromosome complement. In all but one case the babies were normal when only one cell was hypermodal, or when several cells were hypermodal but present in only one colony or one culture vessel. One case had an extra No. 20 chromosome in one cell. Although the child had multiple anomalies, they were not characteristic of trisomy 20, and subsequent chromosomal study on the baby postnatally revealed a 46,XX karyotype. The in situ coverslip technique is recommended as the preferred method for prenatal diagnosis, and it is useful as an aid in differentiating true mosaicism from pseudomosaicism.

Amniocentesis↗
PubMed1994

Comparison of three types of ultrasound transducers in evaluating the amniotic fluid index.

The purpose of this study was to determine whether there was good correlation between amniotic fluid index measurements obtained with different types of ultrasound transducer. Women undergoing obstetric ultrasonography for multiple indications between 26 and 40 weeks' gestation had the four-quadrant amniotic fluid index measured with three ultrasound transducers: 3.5-MHz linear, 3.5-MHz sector and 3.5-MHz convex. Pearson product-moment correlation and linear regression analysis were utilized to compare the amniotic fluid index values. Sixty-five women participated in the study. A statistically significant correlation was noted between the three ultrasound transducers evaluated (P < .001). Placental location did not appear to affect the results. Amniotic fluid index values obtained with the sector or convex transducers were as reliable as those obtained with the "gold standard" linear transducer and may be interpreted in the same manner.

Adolescent↗
PubMed1995

Fetal fibronectin concentration in amniotic fluid decreases with advancing gestational age.

OBJECTIVE: The purpose of this study was to investigate the changes in the level of fetal fibronectin in amniotic fluid during the course of pregnancy. METHOD: Amniotic fluid samples were obtained from 74 women whose pregnancies ranged in gestation from 14 to 38 weeks. Fetal fibronectin in amniotic fluid was examined with a sensitive immunoassay using a monoclonal antibody FDC-6 which recognizes a unique epitope (III-CS) of the molecule. RESULTS: Fetal fibronectin levels in amniotic fluid decreased significantly during pregnancy (r = -0.79, P < 0.0001). The mean levels at less than 20 weeks of gestation were significantly higher than those at 20-29 weeks (P < 0.0001) and at 30 weeks to term (P < 0.0001). CONCLUSION: These results must be considered when fetal fibronectin in vaginal fluid is used as an indicator of the rupture of membranes.

Adult↗
PubMed1978

Amniotic fluid transfer of meperidine from maternal plasma in early pregnancy.

Concurrent samples of maternal plasma and amniotic fluid were collected from 40 subjects during the second trimester of pregnancy following a single intramuscular dose of meperidine (100 mg). Maternal meperidine plasma levels were highest in samples collected from 15 to 50 minutes after drug administration. Thereafter the level declined during the next 2 hours. Meperidine was not detected in amniotic fluid until 30 minutes after the intramuscular dose. We estimated that an apparent equilibrium was reached between plasma and amniotic fluid at 120 to 155 minutes after the drug was given to the mother. Normeperidine was not detected in either maternal plasma or amniotic fluid during the time course of this study.

Amniotic Fluid↗
PubMed1989

Prenatal diagnosis of cystic fibrosis. Analytical evaluation of microvillar enzyme determinations in amniotic fluid.

The activity of gamma-glutamyltranspeptidase and total alkaline phosphatase and its isoenzymes has been determined in 261 amniotic fluid samples taken from pregnant women with known normal outcome and in 30 amniotic fluid samples from pregnant women with a 1:4 risk for cystic fibrosis (CF). Preliminarily, 114 amniotic fluid samples were assayed in parallel in three different laboratories, and a good correlation was found even though different assays were used. From the results obtained in control amniotic fluids, normal range and CF-predictive cutoff values were established. No false-negative results were found in this study. Among the predicted affected pregnancies 7 were terminated, and 3 went to term: 1 resulting in a CF-affected child and the other 2 in healthy children. CF was confirmed in all the aborted fetuses. In 1 case the results were inconclusive. In this study numerical results obtained for samples with a 1:4 risk of CF analyzed in the three laboratories were always virtually identical.

Alkaline Phosphatase↗
PubMed2004

The effect of Ramadan fasting on amniotic fluid volume.

OBJECTIVE: This cross-sectional study was carried out to assess the influence of Ramadan fasting on amniotic fluid volume. METHODS: For this purpose 2 groups of fasting (n=28) and non-fasting (n=25) pregnant women were investigated for amniotic fluid index (AFI) and deepest vertical pocket of amniotic fluid in November (Ramadan month) of 2001-2002 in Kerman Prenatal Clinics in Kerman, Iran. Mean of gestational age based on the last menstrual period and ultrasound reports were 29.6 +/- 5.8 week and 29.5 +/- 4.2 week in fasting and non-fasting groups. RESULTS: There was no significant difference between the 2 groups in age, gestational age, gravidity, parity and systolic/diastolic blood pressures. The mean deepest vertical pocket in fasting and non-fasting groups were 65.9 +/- 12.9 mm and 62.7 +/- 6.5 mm and there was no significant difference between the 2 groups in this regard. Mean AFI in fasting group (189.9 +/- 35.9 mm) and in non-fasting group (166.8 +/- 25.3 mm) showed a significant difference (p less than 0.05). CONCLUSION: Based on the results of the present study fasting in Ramadan has no significant effect on the decrease of AFI, deepest vertical pocket and amniotic fluid volume.

Adolescent↗
PubMed1988

Amniotic fluid fibronectin concentrations with advancing gestational age.

Fibronectin, a large-molecular-weight glycoprotein present on cell surfaces and in human plasma, promotes cell adhesion and may modulate reticuloendothelial clearance of particulate debris and bacteria. Amniotic fluid is known to contain a heavily glycosylated variety of fibronectin, and cells derived from amniotic fluid synthesize and secrete fibronectin in tissue culture. The purpose of this study was to determine the relationship between the concentration of fibronectin in amniotic fluid and gestational age. Amniotic fluid samples, obtained from 54 women whose pregnancies ranged in gestation from 15-40 weeks, demonstrated a significant decrease in fibronectin levels with increasing duration of pregnancy (r = -0.70). Diminished concentrations of amniotic fluid fibronectin in the latter stages of pregnancy may represent either decreasing synthesis by amniocytes or a dilutional effect from fetal urine.

Amniotic Fluid↗
PubMed1999

Does an amniotic fluid index of </=5 cm necessitate delivery in high-risk pregnancies? A case-control study.

OBJECTIVE: This study was undertaken to determine whether women with high-risk pregnancies and an amniotic fluid index of </=5 cm require labor induction to prevent adverse perinatal outcomes. STUDY DESIGN: All women at high risk at >/=34 weeks' gestation with an amniotic fluid index of </=5 cm were admitted to the hospital for labor induction. Each woman was compared with the next patient at high risk seen with an amniotic fluid index of >5 cm and the same pregnancy complication. Case patients were also matched with control subjects for maternal race, age, parity, and gestational age. RESULTS: Prospectively, 79 women at high risk with an amniotic fluid index of </=5 cm were compared with 79 control subjects. There were no statistically significant differences between the 2 groups in the risks of thick meconium (P =.29), variable decelerations (moderate P =.27, severe P =.37), amnioinfusion (P =.37), cesarean delivery for fetal distress (P =.4), and umbilical artery pH <7.10 (P =.29). CONCLUSION: High-risk pregnancies with an amniotic fluid index of </=5 cm appear to carry intrapartum complication rates similar to those of similar high-risk pregnancies with an amniotic fluid index of >5.

Adult↗