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PubMed1977

The relationship of cortisol and cortisone to saturated lecithin concentration in ovine amniotic fluid and fetal lung liquid.

Cortisol and cortisone concentrations in ovine amniotic fluid and fetal lung liquid were analyzed with respect to gestational age and fetal lung maturation as reflected by saturated lecithin concentration. In amniotic fluid, the cortisol concentration rises as a function of gestational age while that of cortisone falls (P less than 0.001). The ratio of cortisol/cortisone is significantly related to gestational age (r=0.693, P less than 0.001), and shows an even stronger correlation with saturated lecithin concentration (r=0.832, P less than 0.001). When examined independently of gestational age, the correlation of the cortisol/cortisone ratio to saturated lecithin concentration remains highly significant (r=0.641, P less than 0.001). Similar findings were observed in fetal lung liquid, except that in this fluid both the saturated lecithin concentration and the ratio of cortisol/cortisone are significantly higher than simultaneously determined values in amniotic fluid. These observations provide further evidence that the process of fetal lung maturation is closely linked to the fetal hormonal milieu.

Amniotic Fluid↗
PubMed2002

Trophic effect of multiple growth factors in amniotic fluid or human milk on cultured human fetal small intestinal cells.

OBJECTIVES: To evaluate the role of growth factors in amniotic fluid and in human milk on gastrointestinal adaptation of the fetus and very low-birth-weight infants, the effects of these fluids and multiple growth factors were investigated in a human fetal small intestinal cell line (FHs 74 Int). METHODS: After FHs 74 Int cells were incubated with amniotic fluid, human milk, or recombinant growth factors, growth-promoting activity was measured by [3H]-thymidine incorporation into cells. RESULTS: Incubating cells with amniotic fluid or human milk promoted growth dose dependently. Genistein almost completely inhibited growth-promoting activity in amniotic fluid P = 0.002), and growth was partially inhibited by antibodies against epidermal growth factor (EGF) (P = 0.047), insulin-like growth factor-1 (IGF-1, P = 0.047), or fibroblast growth factor (FGF, P = 0.014). This activity in human milk was inhibited almost completely by genistein (P < 0.0001) and partially inhibited by antibodies against EGF (P = 0.036), IGF-1 (P = 0.009), FGF (P = 0.004), hepatocyte growth factor (HGF, P = 0.001), or transforming growth factor-alpha (TGF-alpha, P = 0.001). Although recombinant EGF, IGF-1, FGF, HGF, and TGF-alpha elicited a synergistic trophic response on cultured cells, the response was much less than with amniotic fluid or with human milk. CONCLUSION: In aminiotic fluid and in human milk, EGF, IGF-1, FGF, HGF, and TGF-alpha have a strong trophic effect on immature intestinal cells and may be involved in perinatal gastrointestinal adaptation.

Amniotic Fluid↗
PubMed1984

An explanation of the low lecithin/sphingomyelin ratio of amniotic fluid in early pregnancy.

We have attempted to determine why the lecithin/sphingomyelin (L/S) ratio of amniotic fluid is lower than 2 during an early stage of pregnancy. We found that, at 16 wk of gestation, long before the fetal lung secretes lecithin into the amniotic fluid, the L/S ratio was about 1. High-density lipoprotein isolated from the amniotic fluid also had such a low L/S ratio. The L/S ratios of the high-density lipoprotein from umbilical cord blood and maternal blood, however, were much higher, viz. 3.7 (+/- 0.25) and 6.4 (+/- 0.33), respectively. The increase coincided with a decrease in their fluorescence polarization. We suggest that the low L/S ratio of 16 wk amniotic fluid is caused by lipolysis of its lecithin, which is derived from fetal or maternal high-density lipoproteins.

Amniotic Fluid↗
PubMed2004

Host defense proteins in vernix caseosa and amniotic fluid.

OBJECTIVE: This study was undertaken to define the spectrum, activity, and spatial distribution of antimicrobial peptides in vernix caseosa and amniotic fluid in the absence of clinical chorioamnionitis. STUDY DESIGN: Characterization of innate immune proteins in vernix and amniotic fluid obtained from pregnancies with gestational ages greater than 37 weeks by Western analysis, immunohistochemistry, and antimicrobial growth inhibition assay. RESULTS: Lysozyme, lactoferrin, human neutrophil peptides 1-3, and secretory leukocyte protease inhibitor were identified by Western analysis in vernix suspensions (n = 25) and amniotic fluid samples (n = 10). Three other important antimicrobial proteins, human beta defensin-2, lactoperoxidase, and LL-37 were not detected. Amniotic fluid and soluble extracts of vernix exhibited muramidase (lysozyme) activity, and there was selective efficacy in inhibiting growth of common perinatal pathogens. Antimicrobial peptides were concentrated in discrete, organized, acellular "granules" embedded in the vernix lipid matrix. CONCLUSION: In the absence of chorioamnionitis, vernix and amniotic fluid contain an organized pool of antimicrobial peptides with a defined spectrum of bioactivity against common bacterial and fungal pathogens.

Adolescent↗
PubMed1985

Somatomedin-C/insulin-like growth factor I-binding proteins in human amniotic fluid and in fetal and postnatal blood: evidence of immunological homology.

By using the chemical cross-linking agent dis-succinimidyl suberate and [125I]somatomedin-C/insulin-like growth factor I (Sm-C/IGF-I) to affinity label Sm-binding proteins, we identified a 30,000- to 40,000-dalton (30-40K) [125I] Sm-C-binding protein complex in midterm amniotic fluid and cord blood. An antibody raised against a Sm-binding protein purified from midterm amniotic fluid recognized this labeled complex not only in amniotic fluid but also in fetal serum and term cord and several postnatal human plasmas, indicating that the 30-40K Sm-binding proteins in each are similar or identical. The binding proteins in amniotic fluid appear to possess binding sites specific for Sm-C, because under the conditions employed, unlabeled Sm-C was at least 10-fold more potent than IGF-II or multiplication-stimulating activity in competing with [125I]Sm-C for binding. Although [125I]GF-II could be cross-linked to similarly sized proteins, unlabeled Sm-C also competed for this binding better than either unlabeled IGF-II or MSA (at least 5-fold greater potency). These findings suggest that this amniotic fluid Sm-binding protein is primarily a carrier of Sm-C, but does not exclude the possibility that a binding site or a distinct binding protein exists which is specific for IGF-II but not amenable to cross-linking by the procedure used. Because unlabeled Sm-C was less potent in inhibiting the binding of [125I]Sm-C to amniotic fluid than to cord plasma proteins, the amniotic fluid binding protein is either more abundant or less avidly binds [125I]Sm-C than the cord plasma binding protein.

Affinity Labels↗
PubMed2001

A longitudinal study of amniotic fluid index in normal pregnancy in Nigerian women.

OBJECTIVE: To establish normal reference values of amniotic fluid index by week of gestation for normal pregnancies in our population. METHOD: A longitudinal prospective assessment of amniotic fluid index in healthy pregnant women carrying singleton pregnancies. The subjects were recruited at 20 or 22 weeks of gestation and concluded at 40 or 42 weeks of gestation. The numeral data were analyzed on an IBM Personal System 2 computer with statistical and graphical packages. RESULT: from a mean of 17.18 cm at 20 weeks gestation, the amniotic fluid index rose progressively to a peak of 20.39 cm at 26 weeks gestation. It then gradually declined to a mean of 8.37 cm at 42 weeks gestation. CONCLUSION: Gestational age specific values of amniotic fluid index should be used and the 5th and 95th percentiles taken as lower and upper limits of normal, respectively.

Amniotic Fluid↗
PubMed1990

Detection and enumeration of colonic mucosal cells in amniotic fluid using a colon epithelial-specific monoclonal antibody.

Since its introduction, prenatal diagnosis of chromosomal and metabolic disorder by midtrimester amniocentesis has relied upon the use of a mixture of fetal cells obtained from amniotic fluid. Little knowledge has been gained in the sorting of these cells for diagnosis of tissue-specific disorders. In an attempt to determine the contribution of fetal colonic mucosal cells to the overall amniocyte population, we used the colonic epithelial-specific monoclonal antibody (MC-Ab) 7E12H12, IgM isotype. Specimens of the small intestine, colon, buccal mucosa, kidney, urinary bladder, and umbilical cord were obtained from electively aborted normal fetuses of 12-28 weeks' gestation. All of these specimens were examined with 7E12H12 by the immunoperoxidase technique. The MC-Ab reacted with the colonic epithelial cells but not with any of the other tissues. In addition, 40 amniotic fluid samples obtained from women between 16 and 18 weeks of gestation, who underwent amniocentesis because of advanced maternal age, were tested using a fluorescent activated cell sorter. Among the amniotic fluid specimens examined, 18.4 +/- 10.3 per cent cells reacted with 7E12H12. Double immunofluorescence studies revealed that all Mc-Ab-stained cells contained secretory component, confirming that they were epithelial in origin. All fetuses whose amniotic fluid was analysed had normal karyotypes and amniotic fluid alpha-fetoprotein levels that were also normal. This study demonstrates that cell-specific Mc-Ab can be used to detect colon cells in the amniotic fluid and that colon cells contribute significant numbers in the mixture of amniotic fluid cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Amniotic Fluid↗
PubMed1984

Specific 5 alpha-dihydrotestosterone receptor and 5 alpha-reductase activity in human amniotic fluid cells.

A macromolecular component which specifically binds tritium-labeled-dihydrotestosterone is present in cultured amniotic fluid cells. The androgen-binding complex is characterized by a 3.6S sedimentation coefficient, an apparent dissociation constant of 1 nmol/L, a mean binding capacity of 243 +/- 140 fmol/mg of DNA, and a specificity for testosterone and dihydrotestosterone. Similar properties have been reported for the androgen receptor of the fetal genital skin fibroblast, which suggests that the tritium-labeled-dihydrotestosterone-binding component in amniotic fluid cells is the androgen receptor. Amniotic fluid cell monolayers incubated with serum-free medium containing testosterone are able to transform testosterone into dihydrotestosterone. The 5 alpha-reduced product has been characterized by thin-layer chromatography and capillary column gas-liquid chromatography. Androgen receptors and 5 alpha-reductase activity are expressed in amniotic fluid cells. The prenatal diagnosis of 5 alpha-reductase deficiency or complete androgen insensitivity syndrome (testicular feminization) is thus theoretically possible and obviously prenatal testing would be indicated in the family at high risk.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed2006

Elevation of macrophage colony-stimulating factor in amniotic fluid at late stage of normal pregnancy.

PROBLEM: Macrophage colony-stimulating factor (M-CSF) promotes placental growth and maintenance, and regulates trophoblast invasion into the placental bed. We evaluated whether the amniotic fluid M-CSF levels at the late stage of normal pregnancy is altered compared with those at the middle stage. METHOD OF STUDY: This study enrolled 52 subjects experiencing normotensive pregnancies with single fetuses, of whom 26 were women at the late stage (term gravidas) and 26 were women at the middle stage (controls). The average gestational age at entry was 38 weeks of gestation and 17 weeks, respectively. Amniotic fluid was collected from these subjects. Amniotic fluid M-CSF levels were determined by the enzyme-linked immunosorbent assay method then compared between term gravidas and controls. RESULTS: Amniotic fluid M-CSF concentrations were 4815 pg/mL (median) in term gravidas and 3795 pg/mL in controls; the concentrations were significantly higher in term gravidas than in controls. CONCLUSIONS: We demonstrated a significant increase in amniotic fluid M-CSF levels in term gravidas. These results suggest that elevated levels of M-CSF in amniotic fluid have an important immunological function in the maintenance of pregnancy and fetal growth.

Adult↗
PubMed1980

Amniotic fluid C-peptide in normal and insulin-dependent diabetic pregnancies.

Glucose, insulin and C-peptide were determined in amniotic fluid from 28 normal and 46 insulin-treated diabetic pregnant women. Glucose, insulin and C-peptide concentrations in amniotic fluid were higher in the diabetics than in the normal subjects. In diabetic women insulin levels did not correlate with birth weight or birth weight adjusted for gestational age, but C-peptide did. C-peptide correlated poorly with insulin (p < 0.05) in diabetics but closely (p < 0.002) in normal subjects. These results suggest that amniotic fluid investigations in insulin-treated diabetic women should use C-peptide assays as these seem to reflect more closely the insulin production of the fetus than do insulin assays. There were no differences in amniotic fluid glucose, insulin and C-peptide concentrations where the amniotic fluid lecithin-sphingomyelin ratio indicated fetal pulmonary maturity or immaturity.

Adolescent↗
PubMed1996

1-Deamino-[8-D-arginine] vasopressin-induced maternal plasma hypoosmolality increases ovine amniotic fluid volume.

OBJECTIVE: Maternal 1-deamino-[8-D-arginine] vasopressin (a selective antidiuretic agonist) and oral water loading decrease maternal and fetal plasma osmolality and markedly increase fetal urine flow in sheep over 24 hours. We hypothesized that a sustained reduction in plasma osmolality would increase the amniotic fluid volume. STUDY DESIGN: Pregnant sheep (130 +/- 1 days, n = 6) were given oral water loading (2000 ml) and intravenous 1-deamino-[8-D-arginine] vasopressin (20 microgram injection followed by 4 micrograms/hr) to induce maternal urinary antidiuresis and to maintain a maternal plasma osmolality decrease of approximately 20 mOsm/kg for 48 hours. Fetal plasma osmolality, electrolytes, atrial natriuretic factor, and arginine vasopressin levels, fetal swallowing activity, and fetal urine flow and composition were measured each study day, and amniotic fluid volume was measured by tracer dilution before and at 48 hours of plasma hypoosmolality. RESULTS: In response to 1-deamino-[8-D-arginine] vasopressin and water loading, maternal plasma osmolality decreased (298 +/- 1 to 275 +/- 3 mOsm/kg), mirrored by fetal plasma hypoosmolality (293 +/-1 to 271 +/- 3 mOsm/kg). Fetal urine osmolality (155 +/- 16 to 117 +/- 10 mOsm/kg) and amniotic fluid osmolality significantly decreased (281 +/- 3 to 269 +/- 5 mOsm/kg). Fetal urine flow rate significantly increased (0.33 +/- 0.06 to 0.51 +/- 0.04 ml/min), whereas fetal swallowing activity decreased (56 +/- 7 to 33 +/-5 swallows per hour). In response to alterations in fetal fluid dynamics, amniotic fluid volume significantly increased from 493 +/- 80 to 839 +/- 160 ml. CONCLUSION: Chronic maternal 1-deamino-[8-D-arginine vasopressin-induced plasma hypoosmolality induces a sustained reduction in fetal swallowing activity and an increase in fetal urine production, which results in a marked increase in amniotic fluid volume. Use of maternal 1-deamino-[8-D-arginine] vasopressin and oral fluid loading has the potential for manipulation of amniotic fluid volume homeostasis and may prove useful in the treatment of oligohydramnios.

Amniotic Fluid↗
PubMed2004

Maternal serum, amniotic fluid and cord leptin levels at term: their correlations with fetal weight.

AIMS: To investigate the relationship between fetal weight and leptin levels in maternal serum, amniotic fluid and umbilical cord. METHODS: Forty pregnant women presenting for antenatal care at early weeks of gestation were enrolled for the study. Maternal and cord blood samples for leptin measurement were obtained at birth. Amniotic fluid samples were recovered by amniotomy performed during labor. Maternal body mass index and placental weight were also recorded. Leptin measurement was carried out using the ELISA method. Spearman's correlation test was used for comparison of non-parametric data. RESULTS: Leptin concentration in venous cord blood correlated significantly with birth weight and placental weight whereas maternal serum and amniotic fluid leptin levels did not show correlation with birth weight. There were no significant correlations between leptin levels in maternal serum, cord blood and amniotic fluid. CONCLUSION: We conclude that lack of correlation between leptin levels in mother, cord and amniotic fluid suggest that these compartments may be non-communicating separate units or have different mechanisms regulating leptin synthesis or degradation, and that leptin in maternal blood and amniotic fluid may not have a direct effect on fetal growth but rather a different role in pregnancy.

Adult↗
PubMed2002

An animal model for assessment of amniotic fluid clearance from the middle ear.

HYPOTHESIS: To determine the time needed for clearance of amniotic fluid from the middle ear after birth, an animal model study was performed. BACKGROUND: Before birth, the middle ear is full of amniotic fluid, and there is controversy about the time it takes for it to clear postnatally. This is of importance because it is suspected that amniotic fluid in the middle ear of the newborn may affect results of screening of hearing when using otoacoustic emissions. METHODS: Adult and neonatal guinea pigs underwent a right-side cochleotomy followed by baseline otoscopy, tympanometry, and auditory nerve- and brainstem-evoked response (ABR) measurements of the left ear. Subsequently, the animals' left middle ears were filled with saline through a hole drilled in the bulla. Over the next few days, assessment of saline clearance was conducted by repeated left-side otoscopy, tympanometry, and measurement of ABR. RESULTS: After filling the middle ear with saline, the tympanic membrane was opaque, a type B tympanogram was obtained, and the ABR threshold was elevated. After an average of 6.3 +/- 3.0 days, air bubbles were seen in otoscopy, a type C tympanogram was obtained, and the ABR threshold improved. Finally, after an average of 9.5 +/- 2.7 days, all 3 parameters returned to their baseline values. CONCLUSION: Taking into consideration that this is an animal study, the results suggest that clearance of amniotic fluid from the newborn middle ear takes longer than has been generally thought. In addition, an animal model for assessing the clearance of fluid from the middle ear has been developed.

Acoustic Impedance Tests↗
PubMed1980

Isotope dilution analysis of methylcitric acid in amniotic fluid for the prenatal diagnosis of propionic and methylmalonic acidemia.

A stable isotope dilution assay for methylcitric acid in amniotic fluid was developed to provide rapid prenatal diagnosis of the inherited disorders propionic acidemia and methylmalonic acidemia. The method utilizes two 2H3-labeled diastereoisomers of methylcitric acid as internal standards, isolation by liquid partition chromatography and quantitation of the trimethyl esters by chemical ionization selected ion monitoring gas chromatography-mass spectrometry. Methylcitric acid at a concentration of 0.38 +/- 0.10 mumol/l was detected in normal amniotic fluid. Highly elevated levels of 7.87 and 9.16 mumol were found in the fluids surrounding fetuses affected with propionic acidemia and levels of 1.79, 2.72 and 12.27 mumol were found for fetuses with methylmalonic acidemia. Methylcitric acid was not elevated in the amniotic fluid of a fetus heterozygous for propionic acidemia. In the five pregnancies at risk for propionic acidemia, and three pregnancies at risk for methylmalonic acidemia, the levels of methylcitric acid in amniotic fluid gave the diagnosis in all cases. Measurement of methylcitric acid in amniotic fluid therefore provides a rapid and reliable method for the prenatal diagnosis of these genetic disorders.

Amino Acid Metabolism, Inborn Errors↗
PubMed1982

Hypoxanthine levels in amniotic fluid: an indicator of fetal hypoxia?

During hypoxia there is an increased formation of hypoxanthine from the consumption of ATP; simultaneously the oxidation into uric acid is decreased. The purpose of this study was to determine possible correlations between hypoxanthine concentrations in the amniotic fluid and states of fetal hypoxia. We obtained 83 amniotic fluid samples from 68 patients during pregnancy or delivery. Hypoxanthine was assayed fluorimetrically according to GARDINER [4]. In the course of pregnancy, hypoxanthine levels in the amniotic fluid rise slightly. A marked increase occurs during delivery (without labor mean = 3.4 +/- 0.9 mumol/l, with labor mean = 7.0 +/- 5.4 mumol/l, p less than 0.02). There is no significant difference in the levels obtained from the first and second stages of labor. In intrauterine fetal death (Fig. 1) and in depressed newborns (Tab. I) there were increased hypoxanthine levels in the amniotic fluid, this was not seen in other complications of pregnancy. Independently from the fetal state increased hypoxanthine concentrations may occur in the amniotic fluid evidently as a consequence of labor activity. Thus the determination of hypoxanthine levels in the amniotic fluid cannot be used for the diagnosis of fetal hypoxia.

Adenosine Triphosphate↗
PubMed2002

Relationship between erythropoietin levels both in cord serum and amniotic fluid at birth and abnormal fetal heart rate records.

BACKGROUND: Our data in rats suggest that an elevated amniotic fluid erythropoietin (EPO) level at birth indicates antepartum fetal hypoxia. However, the short gestation period in rats does not permit a direct comparison of our data with humans. METHODS: We conducted a retrospective study of the relationship between EPO levels at birth and abnormal fetal heart rate (FHR) records in 113 infants. RESULTS: Among the cesarean section group, the cord serum and amniotic fluid EPO levels in the infants with antepartum abnormal FHR records were significantly higher than those in the control infants. Among the vaginal delivery group, the cord serum EPO levels in the infants with intrapartum abnormal FHR records was significantly higher than that in the control infants. The EPO levels in either cord serum and amniotic fluid discriminated between infants with antepartum abnormal FHR records. The control infants had a sensitivity of 83% and a specificity of 96%. Six of the seven infants with abnormal EPO levels in both cord serum and amniotic fluid had symptoms of prolonged fetal hypoxia. Five infants with abnormal EPO levels in only cord serum had symptoms of acute fetal hypoxia before birth. Four of the 14 infants with abnormal EPO levels at birth had poor outcomes in the neonatal period. CONCLUSIONS: We concluded that EPO levels in both cord serum and amniotic fluid at birth are valuable for determining the timing of fetal hypoxia and may predict the outcome in the neonatal period.

Amniotic Fluid↗
PubMed1993

The temporal relationship between maternal blood and amniotic fluid glucose levels.

OBJECTIVE: Our purpose was to examine the temporal relationship between maternal blood and amniotic fluid levels. STUDY DESIGN: Glucose levels were measured on 158 paired samples from maternal plasma and amniotic fluid obtained from healthy women undergoing genetic amniocentesis at 15 to 20 weeks of gestation. The samples of venous blood and amniotic fluid were drawn at different time intervals, randomly assigned from 0 to 200 minutes. Linear regression analysis was used to test the relationship. The significance was tested by two-tailed t test. RESULTS: A good significant correlation (r = 0.78, p < 0.01 and r = 0.67, p < 0.05) was found at 21- to 40- and 121- to 140-minute intervals, respectively. CONCLUSION: The amniotic fluid glucose level reflects the maternal blood glucose levels at specific lag times.

Adult↗
PubMed1985

Amniotic fluid insulin, C peptide concentrations, and fetal morbidity in infants of diabetic mothers.

Glucose, insulin, C peptide, and insulin antibody concentrations were measured in amniotic fluid collected under basal conditions and 2 hours after an arginine challenge from 61 insulin-treated diabetic women (12 basal and 49 after arginine challenge) and 31 nondiabetic pregnant women in late gestation (23 basal and eight after arginine challenge). The insulin, C peptide, and glucose concentrations were significantly higher in diabetic pregnant women than in nondiabetic pregnant women in each case. In the amniotic fluid obtained after arginine challenge in diabetic pregnant women, C peptide concentration was correlated with both insulin concentration (r = 0.61) and birth weight (r = 0.53). The insulin and C peptide concentrations were significantly higher (p less than 0.025) in samples from diabetic pregnancies associated with fetal morbidity than from diabetic pregnancies without fetal morbidity. Basal amniotic fluid insulin and C peptide concentrations were slightly greater in overweight infants of diabetic mothers compared to those of normal weight, whereas the differences for insulin and C peptide concentrations in the amniotic fluid obtained after arginine challenge were highly significant (p less than 0.0125 and p less than 0.0005, respectively). Finally insulin and C peptide concentrations in the amniotic fluid obtained after arginine challenge in diabetic pregnant women showed a correlation with maternal metabolic control but not with the degree (White classification) of maternal diabetes. No or negligible interference of insulin antibody in the radioimmunoassay of insulin in amniotic fluid was observed.

Amniocentesis↗