Amniotic Fluid Of Patients Research Articles

Tumor necrosis factor-α is elevated in plasma and amniotic fluid of patients with severe preeclampsia

Objective: Our purpose was to investigate whether markers for activation of the immune system are present in patients with preeclampsia by assessing maternal plasma and amniotic fluid for tumor necrosis factor-α and interleukin-1β. Study Design: Twenty-one patients with severe preeclampsia composed the study group (group A). An antepartum comparison group was composed of healthy nulliparous patients not in labor and matched for gestational age (group B). Another control group consisted of term nulliparous patients in labor with uneventful pregnancies (group C). Maternal plasma samples were collected from all patients at recruitment and from patients in groups A and C immediately after delivery and again 20 to 24 hours post partum. Amniotic fluid was also collected from patients in groups A and C during labor. All samples were collectively assayed for tumor necrosis factor-α and interleukin-1β by specific enzyme-linked immunoassays. Results: Before labor tumor necrosis factor-α was detected more frequently in the plasma of preeclamptic patients than in the plasma of patients in group B (12/16 vs 5/16, p < 0.05) and in higher concentrations (median 35 pg/ml vs median 0 pg/ml, p < 0.05). Although tumor necrosis factor-α was frequently detected in the plasma of patients in group C in early labor (16/20), concentrations were higher in the four preeclamptic patients first sampled in early labor (210 pg/ml vs 65 pg/ml, p < 0.05). Similarly, amniotic fluid levels of tumor necrosis factor-α were increased in preeclamptic patients compared with control patients. At delivery tumor necrosis factor-α was more likely to be identified in the plasma of preeclamptic patients and was found in higher concentrations, but by 20 to 24 hours post partum measurements in the preeclamptic and control patients were similar. There were no differences in the frequency with which interleukin-1β was detected or the concentration of interleukin-1β in any of the samples. Conclusions: Tumor necrosis factor-α is increased in the plasma and amniotic fluid of patients with severe preeclampsia. These data are suggestive of a role for abnormal immune activation in the pathophysiologic mechanisms of preeclampsia. Objective: Our purpose was to investigate whether markers for activation of the immune system are present in patients with preeclampsia by assessing maternal plasma and amniotic fluid for tumor necrosis factor-α and interleukin-1β. Study Design: Twenty-one patients with severe preeclampsia composed the study group (group A). An antepartum comparison group was composed of healthy nulliparous patients not in labor and matched for gestational age (group B). Another control group consisted of term nulliparous patients in labor with uneventful pregnancies (group C). Maternal plasma samples were collected from all patients at recruitment and from patients in groups A and C immediately after delivery and again 20 to 24 hours post partum. Amniotic fluid was also collected from patients in groups A and C during labor. All samples were collectively assayed for tumor necrosis factor-α and interleukin-1β by specific enzyme-linked immunoassays. Results: Before labor tumor necrosis factor-α was detected more frequently in the plasma of preeclamptic patients than in the plasma of patients in group B (12/16 vs 5/16, p < 0.05) and in higher concentrations (median 35 pg/ml vs median 0 pg/ml, p < 0.05). Although tumor necrosis factor-α was frequently detected in the plasma of patients in group C in early labor (16/20), concentrations were higher in the four preeclamptic patients first sampled in early labor (210 pg/ml vs 65 pg/ml, p < 0.05). Similarly, amniotic fluid levels of tumor necrosis factor-α were increased in preeclamptic patients compared with control patients. At delivery tumor necrosis factor-α was more likely to be identified in the plasma of preeclamptic patients and was found in higher concentrations, but by 20 to 24 hours post partum measurements in the preeclamptic and control patients were similar. There were no differences in the frequency with which interleukin-1β was detected or the concentration of interleukin-1β in any of the samples. Conclusions: Tumor necrosis factor-α is increased in the plasma and amniotic fluid of patients with severe preeclampsia. These data are suggestive of a role for abnormal immune activation in the pathophysiologic mechanisms of preeclampsia.

Origin of macrophage colony-stimulating factor (M-CSF) and granulocyte colony-stimulating factor (G-CSF) in amniotic fluid.

A large amount of M-CSF and G-CSF exists in human amniotic fluid and both are considered to have some physiological affect on maintaining pregnancy. We therefore examined the source of M-CSF and G-CSF found in the amniotic fluid. The average level of M-CSF in the amniotic fluid of patients without complications was 17.3 +/- 8.5 ng/ml and that of G-CSF 1.85 +/- 1.72 ng/ml, both being high values. In neonatal urine, the average level of M-CSF was also very high, 144.3 +/- 97.0 ng/ml, but that of G-CSF was below the determination limit of 60 pg/ml. Immunohistochemical staining indicated that production of M-CSF and G-CSF was localized in the epithelial cells of fetal membrane. On the basis of the above observations, M-CSF was found to derive from neonatal urine and the epithelial cells of fetal membrane, and G-CSF from the epithelial cells of fetal membrane.

Detection of intra-amniotic infection by gas-liquid chromatography.

The use of gas-liquid chromatography to detect short-chain organic acids in the amniotic fluid of patients with amnionitis has been previously described. Most of the studies describe patients in the early third trimester with such infections. The purpose of the current study was to confirm the correlation of infection with increased production of organic acids and to assess the effect of gestational age on the presence of these short-chain fatty acids in the amniotic fluid. Six patients with confirmed chorioamnionitis were used as positive control subjects. Seventy-two patients at various gestational ages from 18 to 42 weeks with negative Gram's stain and culture results from the amniotic fluid were used as negative control subjects. The data revealed an increased production of organic acids, particularly pyruvic, oxalic and succinic, in patients with amnionitis regardless of gestational age. Interestingly, patients with noninfected amniotic fluid also revealed an increase in the concentrations of volatile organic acids between 27 and 32 weeks' gestation. It appears from this study that previous results correlating chorioamnionitis with an increased production of organic acids in the amniotic fluid may have been confounded by gestational age.

Tumor necrosis factor in preterm and term labor

Our objective was to determine if labor (term and preterm) and microbial invasion of the amniotic cavity were associated with changes in amniotic fluid concentrations of tumor necrosis factor. Amniotic fluid was retrieved by transabdominal amniocentesis from 269 women in the following groups: midtrimester (n = 38), preterm labor with intact membranes (n = 52), preterm premature rupture of membranes (n = 74), term in active labor (n = 84), and term not in labor (n = 21). Fluid was cultured for aerobic and anaerobic bacteria and for Mycoplasma species. Tumor necrosis factor was measured with a commercially available enzyme-linked immunosorbent assay validated for amniotic fluid (sensitivity 60 pg/ml). Amniotic fluid from pregnant women in the second and third trimesters who were not in labor did not contain tumor necrosis factor. Among women in preterm labor, 92.3% (12/13) of patients with a positive amniotic fluid culture had detectable tumor necrosis factor in the amniotic fluid (median 820 pg/ml, range less than 60 to 2340 pg/ml). In contrast, only 10.2% (4/39) of women with a negative amniotic fluid culture had detectable tumor necrosis factor. Histopathologic chorioamnionitis was found in all patients who had a positive amniotic fluid culture, and tumor necrosis factor was detectable in the amniotic fluid of all but one of these patients. Among women in active labor at term, 25% (21/84) had detectable tumor necrosis factor in the amniotic fluid. Tumor necrosis factor was detected more frequently in the amniotic fluid of patients with a positive amniotic fluid culture than in patients with a negative culture (46.6% [7/15] vs 20.2% [14/69], p = 0.047). Amniotic fluid concentrations of tumor necrosis factor were significantly higher in patients with preterm premature rupture of membranes, labor, and a positive amniotic fluid culture than in the other subgroups of patients with preterm premature rupture of membranes. Parturition in the setting of microbial invasion of the amniotic cavity is associated with activation of the cytokine network as demonstrated by the detection of tumor necrosis factor in human amniotic fluid.

Hyaline membrane disease and surfactant protein, SAP-35, in diabetes in pregnancy.

Surfactant-associated protein of Mr 28,000 to 35,000 (SAP-35) is an abundant glycoprotein present in the alveolus of the lung, which imparts both structural organization to surfactant phospholipids and provides regulatory information controlling surfactant phospholipid secretion and metabolism. SAP-35 expression is enhanced by 3'-5'-cyclic adenosine monophosphate and epidermal growth factor during perinatal differentiation of type II epithelial cells. Its synthesis and RNA are also controlled by a variety of inhibitory factors, which include transforming growth factor and insulin. Glucocorticoids both enhance and inhibit SAP-35 expression in fetal lung explants. There is evidence that fetal hyperinsulinemia or hyperglycemia, or both, inhibit the morphologic differentiation of the type II epithelial cell in association with decreased phospholipid surfactant synthesis or secretion. Insulin is also a potent inhibitor of SAP-35 expression in fetal lung tissue, and decreased SAP-35 was previously noted in amniotic fluid of patients with diabetes during pregnancy. Recent progress in the management of diabetes in pregnancy, characterized by more rigorous metabolic control, has decreased the risk of hyaline membrane disease for the infant of the diabetic mother and is associated with normal levels of SAP-35 in amniotic fluid. Hyaline membrane disease remains a major cause of morbidity in infants of diabetic mothers but may also reflect a higher incidence of premature delivery, cesarean section, and asphyxia at delivery as well as inhibition of pulmonary surfactant phospholipid synthesis or expression of the surfactant protein SAP-35.

Maternal levels of pregnancy-specific beta 1-glycoprotein (SP-1) are elevated in pregnancies affected by Down's syndrome.

Concentrations of pregnancy-specific beta 1-glycoprotein (SP-1) were measured in maternal blood and amniotic fluid of patients with a trisomic fetus and compared with that of a cytogenetically normal fetus at weeks 16-19 of pregnancy. The SP-1 concentrations were significantly elevated in the sera of women with a Down's syndrome fetus, whereas amniotic fluid levels were only slightly increased. It is suggested that high levels of maternal SP-1 in the second trimester of pregnancy may be a valuable indicator in the prenatal detection of fetal trisomy 21.

Microbiologic and serologic studies of Gardnerella vaginalis in intra-amniotic infection

Our objective was to investigate the role of Gardnerella vaginalis in intra-amniotic infection by use of comparative, quantitative cultures on selective media and by detection of maternal antibody response. Amniotic fluid was collected from patients with intra-amniotic infection and from matched control women. In addition to media for aerobes, anaerobes, and mycoplasmas, we used V agar-selective (Remel, Lenexa, KS) to isolate G vaginalis. Acute and convalescent maternal sera were collected and assayed for antibodies by a microenzyme-linked immunosorbent assay (ELISA) prepared against whole cells of G vaginalis. Gardnerella vaginalis was isolated in the amniotic fluid of 24 (28%) of the 86 patients with intra-amniotic infection, but this was not significantly different from the isolation rate in amniotic fluid of 86 matched controls (21%). No patient exhibited G vaginalis bacteremia. The ELISA performed on paired sera of selected patients showed that 25 had intra-amniotic infection (eight G vaginalis-positive, 17 negative), and 18 were asymptomatic (seven G vaginalis-positive, 11 negative). The amount of G vaginalis antibodies detected by ELISA in acute sera was similar in all four groups. Mean changes during convalescence were small (.053-.084 optical density units) and not significantly different. Although G vaginalis is found commonly in amniotic fluid of patients with intra-amniotic infection, the data do not support a pathogenic role for this organism; however, a facilitating role in polymicrobial infection cannot be excluded.

Labor and infection: II. Bacterial endotoxin in amniotic fluid and its relationship to the onset of preterm labor

We have previously reported the detection of endotoxin in the amniotic fluid of patients with gram-negative intraamniotic infection. Endotoxin or lipopolysaccharide is a potent biologic product capable of inducing prostaglandin release from several cell types and, therefore, may be involved in the onset of human parturition in the presence of intraamniotic infection. This article describes a technique for the quantification of endotoxin in amniotic fluid. The method uses a computer-assisted quantification of the turbidimetric reaction between the Limulus amebocyte lysate and endotoxin. Serial dilutions of Escherichia coli endotoxin in culture-negative amniotic fluid were prepared, and the samples were run in the assay. Amniotic fluid was found to enhance the reaction, and a dilution of 1:20 was required for this biologic fluid to behave similarly to pyrogen-free water. The sensitivity of this kinetic turbidimetric technique in the detection of endotoxin in amniotic fluid was 40 pg/ml. This method was applied to the quantification of endotoxin concentration in amniotic fluid in 26 patients with intraamniotic infection and premature rupture of membranes. Patients in active labor had higher concentrations of endotoxin (median = 47,514 pg/ml) than nonlaboring patients (median = 635 pg/ml) (p < 0.025). Therefore, women with preterm labor had a higher median concentration of endotoxin in amniotic fluid than patients who were not in labor

Failure of endotoxin to cross the chorioamniotic membranes in vitro.

We have previously reported the detection of endotoxin in the amniotic fluid of patients with gram-negative intra-amniotic infection. Endotoxin or lipopolysaccharide (LPS) is a potent biologic product capable of inducing prostaglandin release from several cell types, and therefore may be involved in the onset of human parturition in the setting of intra-amniotic infection. The experiments outlined in this report were designed to determine whether endotoxin crosses chorioamniotic membranes in vitro. Chorioamniotic membranes obtained at the time of elective cesarean section were placed in Ussing chambers used for transport experiments. Endotoxin was placed in one chamber, and serial timed samples were taken from both chambers for endotoxin quantification, which was performed with the limulus amebocyte gel clot assay. Blue dextran was used to exclude the presence of large defects. Bromophenol blue was used to demonstrate membrane permeability to low-molecular weight substances. Endotoxin failed to cross the chorioamniotic membranes in all experiments (n = 11).

Bacterial colonization of amniotic fluid in patients with intact membranes during labor.

Amniotic fluid from gravidas with intact membranes was obtained for bacteriologic culture at the time of cesarean section. The incidence of positive cultures from patients not in labor was 8%. When the length of labor was eight hours or less (mean 6.1 hours) and the membranes were intact, the incidence of positive cultures was 37%; in patients whose length of labor was 12 hours or less (mean 9.7 hours) with intact membranes, 55% of cultures were positive. The incidence of endomyometritis in patients with bacterial growth from the amniotic fluid cultures in each group was 33%, 33%, and 45%, respectively.

Use of obstetric perineal pads in collection of amniotic fluid in patients with rupture of the membranes

Use of obstetric perineal pads in collection of amniotic fluid in patients with rupture of the membranes

The value of alpha-1-fetoprotein determinations in the amniotic-fluid of patients with hydramnios in the diagnosis of fetal anomalies (author's transl)

Little is known about the influence of hydramnios on the alphafetoprotein (AFP)-concentration in the amniotic fluid. We therefore investigated in 19 patients with hydramnios the diagnostic value of the sonographic evidence and the AFP-concentration in the amniotic fluid in relation to prenatal diagnosis of fetal malformations in two independent series. An anlysis of the AFP-concentration in the amniotic fluid can corroborate the diagnosis of a malformation made by sonography and influence decisions concerning the management of pregnancy and delivery. If ultra-sonic tests show no anomalies, significantly increased AFP-concentrations in the amniotic fluid of patients with hydramnions can merely confirm a suspicious of an existing malformation and influence decisions on further diagnostic steps.

Prostaglandins and Postmaturity

Summary: Levels of E and F prostaglandins in amniotic fluid of patients with prolonged pregnancy have been compared with levels of patients in the last 4 weeks of normal pregnancy. The mean F prostaglandin levels in patients going past term (1,293.3 ± 332.87 pg/ml) were considerably lower than those going into spontaneous labour at term (4,276.71 ± 1,469.62 pg/ml). In 43 patients who went past term, the F prostaglandin levels bore a positive correlation to the cervical score (correlation coefficient 0.654; P &lt; 0.001).These studies suggest that prostaglandins play an important role in the spontaneous onset of labour at term and are also responsible for cervical ripening at term.

Failure of bacterial growth inhibition by amniotic fluid

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

Amino acid variations in amniotic fluid and maternal plasma from Rh-sensitized pregnancies: Part II

Amino acids were quantitated by ion-exchange chromatography in amniotic fluid and maternal plasma from Rh-sensitized pregnancies. Twenty-four patients of 34 to 40 weeks' gestation were studied, and results were compared to those in normal pregnancy. Significant differences were found for amino acid concentrations in amniotic fluid and maternal plasma from those patients in whom fetal death occurred. When the fetus survived, amino acid levels were similar to normal levels. In particular, it was noted that proline levels were markedly elevated in the amniotic fluid of patients in whom fetal death occurred (p < 0.001). From this preliminary work arises the interesting possibility that an increased amniotic fluid versus maternal plasma proline level may be of diagnostic assistance in severe Rh disease.

Variations of the carotene and vitamin A levels in the amniotic fluid of patients with prolonged pregnancy: Corti and Marmori: p. 398

Variations of the carotene and vitamin A levels in the amniotic fluid of patients with prolonged pregnancy: Corti and Marmori: p. 398