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PubMedDate not supplied

Microheterogeneity forms of alpha-fetoprotein present in amniotic fluid.

The microheterogeneity forms of human alpha-fetoprotein present in amniotic fluid were studied in affinity immunoelectrophoresis using two lectins: concanavalin A and Lens culinaris agglutinin. Ninety-seven samples of amniotic fluid collected throughout gestation were obtained from pregnancies in which there was no fetal malformation. Two samples of amniotic fluid from pregnancies complicated by anencephaly and one sample obtained from an empty gestational sac were also studied. The changes in relative concentrations of AFP microheterogeneity forms during gestation are described. It is suggested that concanavalin A is suitable for the demonstration of malformations of the central nervous system in the first and second trimester of pregnancy while in the third trimester it would be of no value. The results of this study suggest that Lens culinaris agglutinin might be suitable for this purpose in the third trimester of gestation, but this needs to be confirmed in a larger study. The optimal concentrations of both lectins were investigated. In addition, a simple method of rocket affinity electrophoresis is also described. The possible mechanisms responsible for the changes in relative concentrations of microheterogeneity forms of alpha-fetoprotein during gestation and in pathological conditions are discussed.

Amniotic Fluid↗
PubMed1982

Evaluation of fetal lung maturity by measurement of the procoagulant activity in amniotic fluid.

The procoagulant activity of amniotic fluid (AF) increases with advancing gestational age. AF samples (N = 276) were measured by a modified recalcification time method. The results were expressed as equivalents of Russell's viper venom (RVV) which acts in a similar way as AF by way of direct activation of coagulation factor X. After week 35 of pregnancy RVV values reached or passed 0.09 micrograms/ml. This value represents a threshold indicating fetal lung maturity. In 124 cases postnatal lung maturity was related to RVV equivalents. The predictive value of a mature result was 99.1%, that of an immature one 52.2%. When comparing RVV values with the lung status, surface tension measurements, and L/S ratio a high correlation was found. L/S ratio and procoagulant activity had a correlation coefficient of r = 0.60. Betamethasone seemed to produce the expected changes in the results of RVV assays and surface tension measurements.

Amniotic Fluid↗
PubMed1975

Amniotic fluid volume, total phospholipids concentratio, and L/S ratio in term pregnancies.

Amniotic fluid volume, lecithin/sphringomyelin ratio, total phospholipid concentration and total phospholipid per sac were investigated in 53 term pregnancies. A definite influence of amniotic fluid volume on the phospholipid concentration was noted, while no influence on the L/S ratio was observed. Amniotic fluid volume showed a tendency to decrease after the 40th week of gestation. The total quantity of phospholipids per sac showed no significant variation between the 36th and 42nd week of gestation.

Amniotic Fluid↗
PubMed2000

The amniotic fluid index, single deepest pocket, and two-diameter pocket in normal human pregnancy.

OBJECTIVE: This study was undertaken to determine normative values for amniotic fluid index, single deepest pocket, and 2-diameter pocket across gestation. STUDY DESIGN: Fifty patients with normal pregnancies at each gestational age between 14 and 41 weeks' gestation were recruited prospectively and scanned once. Data were transformed into logarithmic (base 10) values for analysis. Polynomial regression equations were used to predict the normal values for amniotic fluid index, single deepest pocket, and 2-diameter pocket across gestational age and to predict the weekly percentage changes. RESULTS: The mean amniotic fluid index, single deepest pocket, and 2-diameter pocket values were significantly lower among patients at <37 weeks' gestation (n = 1150) than among those at > or =37 weeks' gestation (n = 250; P <.001 for all comparisons). The calculated prevalences of oligohydramnios (amniotic fluid index < or =5 cm, single deepest pocket <2 cm, or 2-diameter pocket <15 cm(2)) were significantly different (P <.0001) for the three techniques (8%, 1%, and 30%, respectively). Hydramnios (amniotic fluid index >24 cm, single deepest pocket >8 cm, or 2-diameter pocket >50 cm(2)) was also diagnosed with significantly different (P <.0001) frequencies (0%, 0.7%, and 3%, respectively). CONCLUSIONS: This is the largest prospective study to date to provide normative data for each of three ultrasonographic techniques used to assess amniotic fluid volume. The single deepest pocket appears to be the preferable method, because its use is least likely to lead to the false-positive diagnosis of either oligohydramnios or hydramnios.

Adult↗
PubMed1978

Antimicrobial effect of amniotic fluid.

The antimicrobial effect of amniotic fluid (AF) obtained during the first (AF1) and second (AF2) trimesters was compared with the third (AF3) against anaerobic bacteria, such as Bacteroides fragilis ss. fragilis (6 strains), Eubacterium lentum (3 strains), and Peptostreptococcus anaerobius (4 strains). Escherichia coli (5 strains) served as a positive control. AF1 supported the growth of all 4 anaerobes (except B fragilis for 4 hours) for the entire 24-hour period tested. AF2 supported the growth of E coli and B fragilis for 24 hours but temporarily inhibited P anaerobius and E lentum. In contrast, AF3 inhibited all bacteria tested for 8 hours or more. It is concluded that AF1 is the least inhibitory, AF3 the most, and AF2 intermediate for the organisms tested. Lack of antimicrobial effect of AF on anaerobic bacteria may be one explanation for the higher incidence of anaerobic infections during absortion than during the prenatal period.

Amniotic Fluid↗
PubMed1999

Amniotic fluid embolism: decreased mortality in a population-based study.

OBJECTIVE: To examine the risk factors and pregnancy outcomes associated with 53 cases of amniotic fluid embolism that occurred in California during the 2-year period January 1, 1994 to December 31, 1995. METHODS: Data were obtained from a computerized database that contains linked records from the vital statistics birth certificate and hospital discharge summaries of both mother and newborn. This database covered all singleton deliveries that occurred in 328 civilian acute-care hospitals in California, which represented 98% of all deliveries in California. All cases of amniotic fluid embolism were examined for other pregnancy complications. RESULTS: There were 1,094,248 deliveries during that 2-year period. Fifty-three singleton gestations had the diagnosis of amniotic fluid embolism, for a population frequency of one per 20,646 deliveries. Fourteen women with amniotic fluid embolism died, for a maternal mortality rate of 26.4%. There were 35 (66%) diagnoses of disseminated intravascular coagulation (DIC), 38 (72%) diagnoses of hemorrhage, and 25 (47%) diagnoses of obstetric shock. Among the 14 women who died, the frequency of DIC (79%) and hemorrhage (71%) was not different compared with that of the survivors (62% and 72%, respectively), but obstetric shock was higher (86%, P = .02) than in survivors (33%). The average maternal length of stay for survivors was 6.5 days (range 3-27 days, median 5 days). The cesarean rate was 60% and the frequency of fetal distress was 49%. CONCLUSION: In this population-based study of reported cases of amniotic fluid embolism, the maternal mortality rate (26.4%) was significantly less than previously reported and might reflect a more accurate population frequency. In addition, patients who survived and patients who died had similar pregnancy complications, suggesting that amniotic fluid embolism was present in all cases and not limited to those who died.

Adult↗
PubMed1987

A comparison of HPLC and TLC in the assessment of amniotic fluid lecithin/sphingomyelin ratio.

One hundred amniotic fluid (AF) specimens of women at 28 to 37 weeks gestation were obtained during labor for lecithin/sphingomyelin ratio (L/S ratio) study by using high performance liquid chromatography (HPLC) and thin layer chromatography (TLC). The results are divided into two groups: one with L/S ratio at or more than 2, and the other with L/S ratio of less than 2. Of the 80 measured by HPLC with the ratio of above 2 or 1.3%, one suffered respiratory distress syndrome (RDS); of the 65 measured by TLC also with the ratio of above 2 or 3.1%, two developed RDS. The result bears no great significance here. However, in the groups with L/S ratio of less than two, the results were very significant: 17 of 20 estimated by HPLC happened to have RDS for an incidence of false positive rate of 15% compared with a 54.3% in 16 of the 35 women evaluated by TLC.

Amniotic Fluid↗
PubMed1978

Melatonin in amniotic fluid during human parturition.

Concentrations of melatonin have been measured in amniotic fluid obtained during late pregnancy and labour. Samples obtained by amniotomy during labour contained higher concentrations of melatonin than samples taken at amniotomy for the induction of labour. Amniotic fluid obtained by amniocentesis in late pregnancy contained lower concentrations of melatonin than amniotic fluid obtained by amniotomy. The implications of these findings are discussed in relation to pineal influences on parturition.

Amniotic Fluid↗
PubMed1979

Inhibition of antigen-induced lymph node cell proliferation by murine amniotic fluid and its components.

Murine amniotic fluid (MAF), alpha-foeto-protein (AFP) and MAF depleted of AFP by affinity chromatography (MAF-AFP) inhibited the T-cell dependent in vitro proliferative responses of lymph node cells sensitized to a variety of soluble antigens. Variable degrees of inhibition were observed with the different antigens used in the assay. In general, the higher the proliferative response induced by a particular antigen, the less it was inhibited by the three inhibitors. Enhancement of proliferation was not infrequently observed at lower concentrations followed by a dose-dependent inhibition as the concentration of the inhibitor was increased. Usually the order of inhibition was MAF greater than MAF-AFP greater than or equal to AFP although variations in inhibitory potency were noted between different preparations of AFP and MAF-AFP. The existence of inhibitors in preparations of MAF depleted of AFP raised the question as to whether MAF contains single or multiple inhibitory factors. The most facile explanation is that two inhbitors exist; AFP and the as yet uncharacterized non-AFP suppressor present in MAF-AFP.

Amniotic Fluid↗
PubMed1979

The lipoprotein composition of amniotic fluid.

The lipoprotein composition of amniotic fluid (AF) has been studied and it was found that it consists of high density lipoprotein (HDL) only. At about the 26th week of pregnancy the HDL content reaches a maximum and decreases thereafter. On crossed immunoelectrophoresis the HDL of AF was separated into two components if the agar layer contained an antiserum against apolipoprotein A-I. The component with the higher electrophoretic mobility (but not the slower moving component) could also be visualized with an antiserum against HDL. When maternal or umbilical cord serum (UCS) was analysed by crossed immunoelectrophoresis using the anti-apoA-I antiserum, we found that they only contained the faster moving lipoprotein component. If UCS was treated with phospholipase A2 and then subjected to crossed immunoelectrophoresis, the slower moving component appeared at the expense of the faster one. Likewise when UCS was incubated with AF from the 15th week of pregnancy or later, the lipoprotein component of UCS with the high mobility was partially converted to the component with the slower mobility. It is concluded that AF probably contains a phospholipase, an enzyme which may promote the onset of labour.

Amniotic Fluid↗
PubMed1977

Immunoreactive insulin in amniotic fluid from Rh-immunized women.

Immunoreactive insulin was measured in amniotic fluid from Rh-immunized women (anti-D antibody). The degree of immunization was expressed by the spectrophotometric index of the amniotic fluid and by the capillary hemoglobin concentration of the newborn. Higher levels of insulin were found in amniotic fluid from severely Rh-immunized mothers than from non-immunized, and a correlation between the degree of immunization and insulin concentration was indicated. To our knowledge this has not previously been demonstrated, and may justify some new hypotheses concerning the pathogenesis of the observed higher frequency of hyperinsulinism in babies of Rh-immunized mothers.

Amniotic Fluid↗
PubMed1985

Amniotic fluid laminin and type IV collagen in normal and pathological pregnancies.

Specific radioimmunoassays for the fragment P1 of human laminin and the 7-S collagen domain of human type IV collagen were used to quantify these basement membrane proteins in second trimester amniotic fluid samples from 21 normal and 41 pathological pregnancies, the latter group being defined by elevated amniotic fluid alpha-foetoprotein (AFP) or abnormal foetal karyotype, or both. The mean laminin P1 concentration in the normal 15 to 18-wk pregnancies was 36 micrograms/l (range 10-77) and that of the 7-S collagen was 46 micrograms/l (range 7-152). The molecular size of the antigens in amniotic fluid from both normal and pathological pregnancies, when assessed by gel filtration was very large, probably representing intact laminin and type IV collagen. Pathological pregnancies, e.g. cases of Turner syndrome, Meckel syndrome and anencephaly often had elevated amniotic fluid laminin and type IV collagen concentrations. A weak, but nevertheless significant, correlation was found between the amniotic fluid laminin and type IV collagen concentrations and also between type IV collagen and AFP, but none between laminin and AFP. In eight pregnancies with foetuses suffering from the congenital nephrotic syndrome of the Finnish type, a genetic disease assumed primarily to involve some component of the glomerular basement membrane, the amniotic fluid concentrations of both laminin and type IV collagen were within normal limits in spite of an elevated amniotic fluid AFP.

Amniotic Fluid↗
PubMed1994

Amniotic fluid index as a predictor of latency after preterm premature rupture of the membranes.

To determine if latency following preterm premature rupture of membranes can be predicted using the amniotic fluid index, a retrospective observational study was performed using patient records to identify those admitted with a diagnosis of preterm premature rupture of membranes. Fifty-one patients with initial evaluation within 48 hours of rupture and gestational age 26 to 34 weeks were identified. Amniotic fluid index was evaluated along with a biophysical profile; these were followed serially until delivery. Delivery was accomplished because of spontaneous labor or chorioamnionitis. Amniotic fluid index at initial evaluation was stratified into three groups: Low (less than 5.0), reduced (4.0 to 7.9), and normal (8.0 or higher). Latency in days from preterm premature rupture of membranes to delivery was evaluated for these groups. A difference was noted in that latency was significantly longer in the group with normal versus low or reduced amniotic fluid index groups. The amount of residual amniotic fluid, as measured by the amniotic fluid index, following preterm premature rupture of membranes, is predictive of latency.

Adult↗
PubMed2001

Maternal-fetal transfer and amniotic fluid accumulation of lamivudine in human immunodeficiency virus-infected pregnant women.

OBJECTIVE: The purpose of this study was to investigate placental transfer and amniotic fluid concentrations of lamivudine in human immunodeficiency virus-infected women who received the agent during pregnancy. STUDY DESIGN: Mothers in the study were receiving antiretroviral therapy that included lamivudine in a clinical setting. Maternal blood, cord blood, and amniotic fluid samples were obtained simultaneously at the time of delivery from 57 mother-infant pairs. RESULTS: At a median of 8.5 hours after the last maternal oral 150-mg dose of lamivudine, median maternal and fetal plasma concentrations were 302 and 240 ng/mL, respectively. Individual maternal and fetal concentrations were strongly correlated (r2 = 0.36; P < 10(-4)), and their median ratio was about 1. The median concentration in the amniotic fluid was 5 times higher than that in maternal plasma (upper range of ratio, 133). CONCLUSION: Lamivudine appeared to cross the placenta by simple diffusion and is concentrated in the amniotic fluid. High amniotic fluid levels of lamivudine may carry both benefits and risks for the child.

Acquired Immunodeficiency Syndrome↗
PubMed2006

Stable expression of a neuronal dopaminergic progenitor phenotype in cell lines derived from human amniotic fluid cells.

Cells from human amniotic fluid derived from the fetus are considered a source of multipotent cells. Their properties have not been fully exploited, partially because unlike other embryonic sources such as embryonic stem (ES) cells, cell lines from amniocentesis samples have not been generated. We have established and characterized the properties of eight individual cell lines. Flow cytometry using several cell surface markers showed that all cell lines generated consisted of homogeneous populations that lack HLAII antigenicity. Using a combination of immunocytochemistry, Western blotting, and RT-PCR, we found weak expression of Oct4 and nestin and strong expression of tubulin-betaIII, MAP2, and tau. Specific markers for cholinergic, (nor)adrenergic, and GABAergic neurons or glia were weakly expressed or absent, whereas expression of factors implicated in early induction of dopaminergic neurons, TGF-beta3 and beta-catenin were present. Further analysis showed strong expression of EN-1, c-RET, PTX3, and NURR1 essential for induction and survival of midbrain dopaminergic neurons, TH, AADC, and VMAT2 components of dopamine synthesis and secretion, and syntaxin1A and SNAP-25 necessary for neurotransmitter exocytosis. This phenotype was retained throughout passages and up to the current passage 36. Expression of neuronal and dopaminergic markers in individual AF cell lines was comparable to expression in neurons induced from ES cells and in IMR-32 and SH-SY5Y neuroblastomas. Our data show that cell lines can be derived from subcultures of amniocentesis, and are primarily composed of a population of progenitors with a phenotype similar to that of committed mesencephalic dopaminergic neurons.

Amniotic Fluid↗
PubMed1982

A serine protease activity of human serum albumin towards 4-methylumbelliferyl-guanidinobenzoate (MUGB) and diisopropyl fluorophosphate (DEP): implications for the use of MUGB reactivity in amniotic fluid in prenatal diagnosis of cystic fibrosis.

4-methylumbelliferylguanidinobenzoate (MUGB) reactivity in plasma from patients with cystic fibrosis and in amniotic fluid from pregnancies leading to children with cystic fibrosis, has been reported to be significantly decreased. We have so far been unable to confirm these findings and have therefore reexamined this reactivity using diisopropylfluorophosphate (DEF), another active site titrant of serine proteases. We have shown that MUGB and DFP are reacting with the same molecules in plasma and amniotic fluid. Using crossed immunoelectrophoresis and SDS-polyacrylamide gel electrophoresis of 3H-DFP labelled plasma and amniotic fluid we have obtained strong evidence that the main contribution of MUGB and DFP reactive protein in plasma and amniotic fluid is identical to serum albumin. The use of MUGB reactivity in amniotic fluid in pregnancies at risk for cystic fibrosis must therefore be reconsidered.

Amniotic Fluid↗
PubMed1989

Amniotic fluid isoamylase activity in uneventful pregnancies.

A kinetic test (Phadebas) was used to determine the isoamylase activity in 50 serum specimens and 159 samples of amniotic fluid. A highly significant difference between the isoamylase patterns of serum and amniotic fluid was ascertained which strongly supports the view that amylase activity in amniotic fluid is not of maternal origin. During the whole course of gestation the activity of pancreatic isoamylase was constantly low whereas there was an increase of nonpancreatic activity (S-type amylase) from 44 +/- 10 U/l in the 18th week of gestation to 445 +/- 170 U/l in week 39/40. A comparison between the dispersion of the ascertained values and the lecithin-sphingomyelin (L/S) ratio showed a clear overlapping. There was a correlation coefficient of r = 0.645 for 115 amniotic fluid specimens examined in our investigation. The findings show that the estimation of nonpancreatic isoamylase (S-type amylase) activity in amniotic fluid is a valuable indirect parameter for determining fetal maturity and fetal lung maturity. The easy and quick determination method will provide even those hospitals with an index of fetal maturity which are presently not in a position to estimate the L/S ratio, thus being of great assistance in the field of premature deliveries.

Amniotic Fluid↗
PubMed1986

Amniotic fluid collagenase inhibitor: correlation with gestational age and fetal lung maturity.

Concentrations of collagenase inhibitor in amniotic fluid correlated with gestational age and with indices of fetal lung maturity such as the lecithin/sphingomyelin ratio and the presence of phosphatidylglycerol. Possible sources of amniotic fluid collagenase inhibitor were sought, and a number of tissues and fluids, both maternal and fetal in origin, were found to contain or synthesize this glycoprotein in significant quantities. The highest concentrations were achieved in cultures of lung fibroblasts implicating the fetal lung as a major source. Although collagenase inhibitor is largely present in a free or available state, its specific role, other than that of a general antiproteinase, has not been determined in amniotic fluid. However, the quantitation of amniotic fluid collagenase inhibitor provides an index of the maturation of the connective tissue of the fetal lung and may reflect the ability of the extracellular matrix to meet neonatal demands.

Amniotic Fluid↗