Amniotic Fluid Albumin Research Articles

Новые белковые маркеры в прогнозе внутриутробной инфекции при преждевременных родах

Objective. To identify prognostic markers of intrauterine infection (IUI) of the fetus and newborn in maternal serum, amniotic fluid, and umbilical cord serum in case of preterm birth. Patients and methods. We examined 93 pregnant women who had preterm birth (PB) from 24 to 33 weeks of gestation. Thirtyfive women delivered babies without any signs of IUI, while 30 women had newborns with mild IUI (conjunctivitis, lymphadenitis, pyoderma) and 28 women had newborns with severe IUI (early neonatal sepsis, advanced herpesvirus infection, chlamydiosis, candidiasis, pneumonia, and meningitis). We measured the levels of alpha 2-macroglobulin (α2-MG) in maternal serum (MS), umbilical cord serum (UCS) using rocket immunoelectrophoresis and in amniotic fluid (AF) using enzyme-linked immunosorbent assay (ELISA). The level of lactoferrin (LF) was assessed using ELISA. MS and UCS levels of albumin (ALB) were measured using biochemical methods, while AF level ALB was evaluated using rocket immunoelectrophoresis. Statistical analysis was performed using logistic regression. Results. We found no association between the concentration of LF in all biological fluids and the condition of newborns. Levels of ALB in MS and UCS also demonstrated no correlation with the condition of newborns. AF ALB in women who delivered babies with IUI (any grade of severity) was significantly higher than that in women who delivered babies without IUI. Women who delivered babies with severe IUI demonstrated the lowest concentration of α2-MG in their serum, whereas women who delivered babies with mild IUI had the highest α2-MG concentration. The AF α2-MG level was 10 to 20 times higher in women who had babies with IUI (any grade of severity) compared to those who had babies without IUI. Conclusion. Low α2-MG level in MS (<2.2 g/L) along with elevated α2-MG level in AF (≥6.0 mg/L) in 86–89% of PB cases indicated generalized fetal IUI and required urgent delivery without prolongation of pregnancy. Key words: albumin, alpha-2-macroglobulin, intrauterine infection, lactoferrin. premature birth

OP01.03: Aortic wall thickness and amniotic fluid albumin in twin growth restricted fetuses

OP01.03: Aortic wall thickness and amniotic fluid albumin in twin growth restricted fetuses

Increased Oxidative Modifications of Amniotic Fluid Albumin in Pregnancies Associated with Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM) is a state of hyperglycaemia and increased oxidative stress with onset during pregnancy. Human serum albumin (HSA) was extracted from 26 GDM and 26 nonGDM amniotic fluid samples collected at 15 weeks gestation and analyzed by mass spectrometry. The majority of all albumin isoforms were oxidized with the cysteinylated HSA as the base peak in the deconvoluted spectrum. The HSA peak areas, from a control sample, had 36% relative standard deviation (RSD) across the six experimental days but using the relative isoform distribution improved the precision to 3-6%. The results show that the relative contribution of permanently oxidized HSA was greater (P = 0.002) and reversibly oxidized HSA was lower (P = 0.006) for GDM compared to nonGDM in the samples measured. This implies that the path toward GDM has been set prior to 15 weeks gestation and results in increased protein oxidation.

Inhibition of fibroblast-populated collagen lattice contraction by an albumin-bound lipid fraction in human amniotic fluid.

Human amniotic fluid inhibits the contraction of fibroblast-populated collagen lattices. Amniotic fluid of 21 weeks' gestation was previously reported to have peak inhibiting activity. An attempt to isolate the inhibitory factor(s) from human amniotic fluid employing a molecular sieving column demonstrated an inhibitory factor near 70,000 molecular weight (repeated three times with triplicate samples). Since albumin has a molecular weight of 68,000 and is in high concentration in amniotic fluid, the removal of albumin by an Affi-Gel Blue (an albumin binding affinity column) was the first step in the purification scheme. The bound human amniotic fluid albumin fraction was eluted from the Affi-Gel Blue column, and the unexpected finding was that this fraction inhibited fibroblast-populated collagen lattice contraction (three repetitions in duplicate). We previously showed that prostaglandins and saturated and unsaturated fatty acids affect fibroblast-populated collagen lattice contraction, and albumin is a carrier for lipids. The eluted albumin fraction was separated into its protein and lipid components. The lipid-free albumin fraction had no fibroblast-populated collagen lattice contraction inhibiting activity (run four times in duplicate). The isolated lipid fraction inhibited fibroblast-populated collagen lattice contraction in a dose-responsive manner (repeated twice in triplicate). It was demonstrated that lipid bound to albumin isolated from human amniotic fluid inhibited fibroblast-populated collagen lattice contraction.

Automated Rapid Assessment of Surfactant and Fetal Lung Maturity

This study reports predictions for clinical respiratory distress syndrome (RDS) by means of a rapid test for fetal lung maturity based on fluorescence polarization of a dye (PCI 6) that partitions between surfactant and albumin in amniotic fluid. The test is completed in approximately 30 minutes and requires collection of a specimen volume of only 0.5 mL amniotic fluid. Results are reported as mg surfactantlg albumin (SIA value) equivalence. Ninety-three infants were delivered within 2 days of a collection of amniotic fluid and were followed up for the presence or absence of symptoms consistent with RDS. Ten infants, two of whom had anomalies, developed RDS. With a threshold of <50 mg/g equivalence to indicate probable occurrence of symptoms consistent with RDS, the SI A value had a sensitivity of 90% for predicting RDS, with a specificity of 87%, a positive predictive value of 45%, and a negative predictive value of 99%. This was comparable to using the lecithin-tosphingomyelin ratio of <2.0, which had a sensitivity of 80%, a specificity of 93%, and positive and negative predictive values of 57% and 98%, respectively. The clinical predictions based on the absence of phosphatidylglycerol were 90% sensitivity, 79% specificity, and 35% and 98% positive and negative predictive values, respectively. SI A values obtained for specimens that were frozen and thawed correlated well with results from nonfrozen specimens. Satisfactory S/A values were obtained with specimens of amniotic fluid that were collected from vaginal pools. Loss of fluorescence polarization because of partition of PCI 6 between albumin and surfactants represents an integrated effect of the surfactants and provides an additional assessment of lung maturity comparable to currently accepted tests. The ligand-based assay requires only a small volume of specimen, is rapid, and can be standardized between institutions. These features indicate that the PCI 6-based assay provides an alternative assessment of lung maturity to currently existing methodologies, or when little specimen is available or there is an urgent need for results.

Multicenter evaluation of TDx test for assessing fetal lung maturity

"TDx Fetal Lung Maturity," an automated assay that measures the relative concentrations of surfactant and albumin in amniotic fluid, was compared with the lecithin/sphingomyelin (L/S) ratio and phosphatidylglycerol determination at five clinical sites. A total of 695 amniotic fluid samples were analyzed, of which 312 were followed by delivery of the infant within three days of sample collection. Of these 312, 24 developed respiratory distress syndrome and seven developed transient tachypnea. With the cutoff for maturity set at a surfactant/albumin value of 50 mg/g, the assay showed a sensitivity of 0.96 and a specificity of 0.88 for all samples, compared with a sensitivity of 0.96 and a specificity of 0.83 for the L/S ratio. The combination of rapid assay (30 min), accurate results, and uniformity among testing centers makes the TDx assay a very promising method.

Effect of albumin and lamellar bodies on fluorescence polarization of amniotic fluid.

Using a probe and procedure developed for the Abbott TDx analyzer, we investigated the influence of albumin on fluorescence polarization of amniotic fluid. Polarization readings increased when albumin was added to either "mature" or "immature" amniotic fluids. Albumin added to a fraction rich in lamellar bodies (10,000 X g pellet) greatly increased polarization readings, but albumin added to the lamellar-body-free fraction resulted in only small increases. Adding increasing amounts of the lamellar-body-rich fraction from mature and immature pools to a constant amount of albumin decreased the polarization readings. We saw no correlation between amniotic fluid polarization and albumin concentration but found a significant correlation between polarization values and either total extractable phospholipids (r = 0.725, P less than 0.001) or the ratio albumin/total extractable phospholipids (r = 0.784, P less than 0.001). The concentration of albumin in amniotic fluid was variable and correlated poorly with gestational age.

AFP transport across the fetal membranes in the human

In this investigation the original observation of a correlation between the concentration of amniotic fluid albumin and maternal serum alpha fetoprotein (AFP), as a proof for amniotic fluid-derived AFP in the maternal compartment is confirmed at 15 and 16 weeks of gestation. In contrast to the earlier reported highly significant relation in this study the correlation is only weak, especially at 15 weeks. This might be in agreement with a more frequent absence of raised maternal serum AFP levels in cases of raised amniotic fluid AFP levels prior to 16 weeks of gestation. Transamniotic AFP transport contributes a minor part of the AFP present in the maternal compartment, as also indicated by the lack of correlation between AFP concentrations in amniotic fluid and maternal serum.

Alpha-fetoprotein and albumin in experimentally-induced exencephaly in the rat.

Alpha-fetoprotein and albumin were quantified in the sera and amniotic fluids from control, Vitamin A-treated non-exencephalic and Vitamin A-treated exencephalic rat fetuses. Exencephaly was associated with amniotic fluid alpha-fetoprotein concentrations which were significantly elevated over those of Vitamin A-treated non-exencephalic and of untreated fetuses. Amniotic fluid albumin concentrations also were higher in the exencephalic fetuses than in the non-exencephalic fetuses. Serum alpha-fetoprotein and albumin concentrations were lower in the exencephalic than in the non-exencephalic fetuses. The results are cosistent with simple diffusion across a defective barrier as the cause of elevated amniotic fluid alpha-fetoprotein concentrations in the presence of open neural tube defects. This experimental model of neural tube defects result in changes in amniotic fluid alpha-fetoprotein similar to those changes found in human amniotic fluid alpha-fetoprotein concentrations in the presence of neural tube defects.

Content of beta-2-microglobulin and albumin in human amniotic fluid. A study of normal pregnancies and pregnancies complicated by haemolytic disease.

Abstract. The content of the low‐molecular weight protein β2‐microglobulin and albumin was measured by immunochemical methods in amniotic fluid from 136 patients in the 13th to the 43rd week of pregnancy. Parallel estimations of β2‐microglobulin in maternal plasma were made in the majority of patients. Some samples of cord serum and urine from the newborn were also analysed. In normal patients the levels of β2‐microglobulin followed the albumin pattern with a peak value around the 24th week and a gradual decrease during the last trimester. In contrast to other proteins β2‐microglobulin showed higher levels in amniotic fluid than in maternal plasma. During the last trimester levels in maternal plasma exhibited a significant increase. Levels in cord serum were higher than in amniotic fluid. Urine from the newborns contained at least 5 times the amount previously found in adults. The results indicate that β2‐microglobulin in amniotic fluid is largely derived from the fetus itself. Patients with pregnancies complicated by haemolytic disease showed significantly higher levels in amniotic fluid than normal patients for comparable periods but the levels showed no close correlation with the degree of fetal involvement. The ratio of β2‐microglobulin to albumin in amniotic fluid was elevated in patients with fetal haemolytic disease. The albumin content showed no significant differences between the clinical groups but tended to decrease more rapidly during the last weeks of pregnancy in patients with fetal haemolytic disease. Further studies of β2‐microglobulin might supply important information about the transfer mechanisms of amniotic fluid proteins and also permit studies of some physiological and pathological processes in the fetus.

Assessment of Rh disease by ratios of bilirubin to albumin and hemopexin to albumin in amniotic fluid.

Abstract We examined 105 amniotic-fluid samples from 36 Rh-sensitized pregnancies for concentration of bilirubin, protein, albumin and hemopexin (heme-binding beta glycoprotein). Bilirubin measurements obtained spectrophotometrically (Liley method) were compared with levels of total protein, albumin, hemopexin and chemically determined bilirubin. Ratios of the concentrations of chemically assessed bilirubin to albumin reflected most accurately the degree of fetal hemolysis and fetal outcome. A ratio above 0.10 was recorded in eight of 10 patients receiving intrauterine transfusions and in two requiring multiple exchange transfusions. A ratio below 0.05 indicated patients needing no or one transfusion. A rising ratio of hemopexin to albumin in 10 cases usually suggested no or mild involvement; leveling (six cases) and falling ratios (15 cases) were found when exchange or intrauterine transfusions were needed. Inconclusive or negative Liley values were observed in four cases, but ratios of bilirubin and hem...

Mechanism of accumulation of amniotic fluid pigment in erythroblastosis fetalis

Studies were performed to elucidate the mechanism of accumulation of amniotic fluid bilirubin pigments in erythroblastosis fetalis. Results revealed that unconjugated bilirubin in amniotic fluid is bound to albumin and that albumin averages 65 per cent of total amniotic fluid protein, even in the presence of fetal hydrops, where total protein is markedly elevated. Saturation of fetal albumin is well below the capacity of this protein to bind bilirubin and a concentration gradient exists between fetal plasma and amniotic fluid which appears to favor the transfer of bilirubin across partitioning membranes. In 3 cases, experimental elevation of amniotic fluid albumin content increased the bilirubin content of amniotic fluid. It is suggested, therefore, that the accumulation of bilirubin in amniotic fluid resembles the transplacental passage of bilirubin from fetus to mother and is dependent on the gradient of bilirubin-albumin complexes across the separatory tissues.

Serum alpha-fetoprotein, albumin, and gamma-G-globulin in the human conceptus.

Serum concentrations of alpha fetoprotein (AFP) in the human conceptus were investigated and compared to the concentrations of albumin and gamma G-globulin. Determinations were made immunochemically over gestational periods from 6.6-39 weeks and in the 1st 3 weeks of newborn life. Serum concentation of AFP increased from 6.6 weeks reaching maximal at about 13 weeks at which time the level decreased rapidly to levels less than 2% of maximum by 34 weeks. Newborn at term had detectable AFP but that disappeared from serum with an average half-life of 5 days during the 1st week of life and with an average half-life of 3 days after the 1st week. Serum albumin levels reached a plateau by 22-24 weeks of gestation remaining at these levels throughout the neonatal period. Average concentrations of albumin in neonatancy were slightly higher than those in mothers. Gamma G-globulin serum concentrations from 6.6-22 weeks of gestation were less than .2 gm/100 ml. After 22 weeks gamma G-globulin increased to levels seen in term infants by 26 weeks. Albumin:AFP ratios in amniotic fluid were much higher than those in bladder urine from 11-13.2 weeks of gestation which indicates the possible existence of an additional source of amniotic fluid albumin besides urine. Clearance of albumin into urine was greater than that of AFP. By gel filtration and ultracentrifugation the molecular size of AFP was similar to that of albumin. Sera of pregnant women did not contain detectable amounts of AFP.