Phosphatidylglycerol In Amniotic Fluid Research Articles

Phosphatidylglycerol in amniotic fluid.

Phosphatidylglycerol in amniotic fluid.

Amniotic fluid phosphatidylglycerol and phosphatidylcholine phosphorus as predictors of fetal lung maturity

The contents of phosphatidylglycerol and phosphatidylcholine phosphorus in amniotic fluid (10,000 × g pellets) were studied as predictors of fetal lung maturity. The presence of phosphatidylglycerol predicted the absence of neonatal respiratory distress syndrome with 99% probability. When phosphatidylglycerol was absent, phosphatidylcholine phosphorus was a reliable predictor if measured 3 to 7 days before delivery. The probability that respiratory distress syndrome would not occur was 94% when phosphatidylcholine phosphorus was >6. When measurement was performed within 2 days of delivery, the probability that respiratory distress syndrome would not occur fell to 69%. As measured in amniotic fluid, phosphatidylglycerol and phosphatidylcholine phosphorus are reliable antenatal predictors of fetal pulmonary maturity and, therefore, are useful in the management of a number of obstetric conditions.

Amniostat-FLM: An initial clinical trial with both vaginal pool and amniocentesis samples

Amniostat-FLM, a new rapid slide agglutination test, was compared with thin-layer chromatography as a method for detecting phosphatidylglycerol in amniotic fluid. This is the first reported use of Amniostat-FLM to evaluate vaginal pool and contaminated vaginal pool amniotic fluid. One hundred one of 161 amniotic fluid samples were collected from the vaginal pool. Thirty-nine of these were contaminated. Vaginal pool amniotic fluid, whether contaminated or not, did not adversely effect the ease of performance, reliability, or interpretation of Amniostat-FLM. This test seems ideally suited to institutions where 24-hour availability of thin-layer chromatography is not available. In institutions where it is available, Amniostat-FLM could be used as a screening test. Amniostat-FLM was found to be significantly less sensitive when compared with thin-layer chromatography in detecting the presence of phosphatidylglycerol. At our institution the screening of amniotic fluid samples with Amniostat-FLM before use of thin-layer chromatography was only cost effective at ≥ 34 weeks of gestation.

Determination of phosphatidylglycerol in amniotic fluid for prediction of foetal lung maturity by microbore-column liquid chromatography

Phosphatidylglycerol (PG) has been determined in amniotic fluid from 55 patients by using a microbore-column liquid chromatographic system. The present analysis time is 1 h 40 min for pretreatment of amniotic fluid and 20 min for a chromatographic run. From 2 ml of amniotic fluid, the PG content has been determined between 1.0 and 0.05 mg/dl. The detection limit of PG is 10 ng. As the injection volume (0.5 μl) is small, repeated analyses are possible if necessary. It is concluded that, in the case of PG values over 0.10 mg/dl, a mother can deliver an infant without respiratory distress syndrome. This method is useful not only for the prenatal evaluation of lung maturity, but also for the assessment of any therapeutic effect.

Amniotic Fluid Phosphatidylglycerol for Prediction of Respiratory Distress Syndrome

Clinical usefulness of phosphatidylglycerol in amniotic fluid has been questioned by many recent studies and its predictive value has not been found to be better than L/S ratio is complicated pregnancy except in diabetes mellitus. Prematurity, birth asphyxia and androgens of the male babies are the other contributory factors for the development of respiratory distress syndrome.

Quantitative determination of phosphatidylglycerol in amniotic fluid by enzymatic assay

Phosphatidylglycerol (PG) was extracted from 54 human amniotic fluids for the assessment of fetal lung maturity. The PG values were derived from an enzymatic assay involving initial conversion of PG to glycerol by phospholipase C and alkaline phosphatase with subsequent analysis of the glycerol formed. This method proved to be reliable when compared with a method for two-dimensional thin layer chromatographic (2D TLC) analysis of amniotic fluid phosholipids. The results revealed that in all but one of 27 amniotic fluids in which no PG was detected by 2D TLC, enzymatic PG concentrations were ⩽ 1.5 μmol/l and out of these, from 10 newborn infants delivered within 72 h of sampling, 4 developed respiratory distress syndrome (RDS). Conversely, in all but one of 27 amniotic fluids found to contain PG by 2D TLC, enzymatic PG concentrations were > 1.5 μmol/l and except for one subject from non-identical twins, no infants developed RDS.

Three methods compared for determining phosphatidylglycerol in amniotic fluid.

Phosphatidylglycerol is one component of amniotic fluid that is unaffected by several of the reported interferences with conventional thin-layer chromatographic measurement of phospholipid. To compare a rapid immunological agglutination test, "Amniostat-FLM", with two-dimensional thin-layer chromatography, we determined phosphatidylglycerol by both methods in 41 amniotic fluid specimens obtained at 31 to 40 weeks of gestation. We also assayed phosphatidylglycerol in 14 of these specimens by an enzymic, colorimetric procedure. The agglutination test is rapid and simple but relatively insensitive; it yielded positive results for only seven of 23 specimens in which phosphatidylglycerol was detected by thin-layer chromatography. In 18 specimens in which no phosphatidylglycerol was detected by thin-layer chromatography, results by Amniostat-FLM were also negative; however, eight of these specimens, assayed by the enzymic method, had phosphatidylglycerol present. Apparently, the Amniostat-FLM detects phosphatidylglycerol only at concentrations exceeding 25 mumol/L, or more than 15% of the total phospholipid composition.

Bacteria causing false positive test for phosphatidylglycerol in amniotic fluid

A case is reported in which phosphatidylglycerol was detected in a sample of vaginal pool amniotic fluid but absent in amniotic fluid obtained at amniocentesis. Bacteria contaminating the fluid are shown to be capable of phosphatidylglycerol production.

Laboratory and clinical evaluation of a rapid slide agglutination test for phosphatidylglycerol

Amniostat-FLM is a recently developed rapid slide agglutination test for amniotic fluid phosphatidylglycerol. We compared phosphatidylglycerol quantitated by two-dimensional thin-layer chromatography with phosphatidylglycerol determined by Amniostat-FLM in 180 amniotic fluid samples. If any level of phosphatidylglycerol by thin-layer chromatography, including a trace, was considered positive, then phosphatidylglycerol by thin-layer chromatography and Amniostat-FLM were concordant in 171 of 180 samples (95%). Both were positive in 123 and both negative in 48 samples. The nine amniotic fluid samples with discrepant results were as follows: Five negative Amniostat-FLM results were associated with trace phosphatidylglycerol by thin-layer chromatography (1% to 2% of total phospholipids), one negative Amniostat-FLM result was associated with 3% phosphatidylglycerol by thin-layer chromatography, and three positive Amniostat-FLM results were associated with negative phosphatidylglycerol by thin-layer chromatography results. There were 14 samples with trace phosphatidylglycerol by thin-layer chromatography; of these, there were nine positive and five negative Amniostat-FLM results. If >2% phosphatidylglycerol by thin-layer chromatography was considered positive, concordance between the two tests was 93% (167 of 180). From these samples, 119 infants were delivered within 72 hours of amniocentesis. There were 100 positive Amniostat-FLM results and all were associated with the absence of respiratory distress syndrome; of the 19 negative Amniostat-FLM results, five were associated with infants who developed respiratory distress syndrome. The present study confirms that Amniostat-FLM is a sample, rapid, and accurate test for determining the presence of phosphatidylglycerol in amniotic fluid.

Absence of phosphatidylglycerol in amniotic fluid of baboons at term

bones. Well-formed cartilage and osseous tissue were easily identified, but the soft tissue was largely resorbed with only ghosts of cells and degenerative changes present. Chorionic villi and trophoblast were not identified in the tissue, which suggested complete resorption of the placental component. Although the gestational age of this ectopic mass is difficult to determine, the extensive ossification indicates that it had progressed to at least 12 weeks before silently aborting. The time of the occurrence of the ectopic pregnancy is not known although the histologic changes suggest a process that occurred over months or years. The operative findings of the small cystic right tuboovarian mass at tubal ligation 4 years previously may have been due to the ectopic pregnancy. In addition, the 2-yeal histology of chronic pain in the right lower quadrant may have been due in part to the ectopic gestation. Differential diagnoses of cartilage and bone within a fallopian tube include dystrophic calcification, heterotopic bone formation, and teratomas in addition to retained ectopic products of conception. In this case the cartilaginous and osseous tissue had the structure and shape of fetal bones, which indicated the presence of a prior ectopic gestation.

Evaluation of the Amniostat-FLM assay for assessment of fetal lung maturity.

Results of the "Amniostat-FLM" assay, a rapid semiquantitative test for phosphatidylglycerol, were compared with determinations of the lecithin/sphingomyelin (L/S) ratio, with phosphatidylglycerol measured by two-dimensional thin-layer chromatography, and with results of the "shake test" for 94 specimens of amniotic fluid. Correlation between results with the Amniostat and the other tests was excellent. All four tests are very accurate when predicting lung maturity. The predictive value of a negative test, i.e., that hyaline membrane disease would not occur, was between 92 and 100%. However, the accuracy of predicted lung immaturity is poor. For all four tests, predictions of lung immaturity were incorrect in more than 50% of the cases. Of the 49 infants born within 72 h of testing, none developed hyaline membrane disease when phosphatidylglycerol was detectable by either method or when the shake test indicated fetal lung maturity, but three infants with L/S ratio greater than 2/1 did develop the disease. The Amniostat provides a rapid screening method for detecting phosphatidylglycerol in amniotic fluid, which could well replace the thin-layer chromatographic method for measuring phosphatidylglycerol in the panel of diagnostic tests for fetal lung maturity.

A cost-effective modification of an immunologic agglutination test for amniotic fluid phosphatidylglycerol.

A cost-effective modification of an immunologic agglutination test for amniotic fluid phosphatidylglycerol.

Amniotic fluid phosphatidylglycerol in diabetic and control pregnant patients at different gestational lengths

Phosphatidylglycerol (PG) and lecithin/sphingomyelin (LS) ratios were stimultaneously determined in 1770 samples of amniotic fluid. PG was defined as “present” when it appeared in at least 2% of the total phospholipids. Comparison of the appearance of PG in samples of amniotic fluid obtained from diabetic and nondiabetic pregnant patients according to LS ratios showed that samples from diabetic patients were less likely to have PG present than those from nondiabetic patients, particularly at LS ratios between 3.1 and 4.0. Because of that, further studies compared the appearance of PG according to gestation in 186 diabetic patients with that in a group of 238 control patients that was composed only of those who underwent repeat cesarean section. Rh-sensitized patients were not included in the control group, since they had delayed appearance of PG. The results showed that the appearance of PG was delayed in patients with Classes B, C, and D-F-R diabetes. In patients with Class A diabetes, the appearance of PG was not significantly different from that in control patients over the entire gestational period, although the appearance of PG may be delayed during early gestation. In contrast, there were no significant differences in LS ratios in various classes of diabetic pregnant patients and control patients at different gestations.

When is an amniocentesis for fetal maturity unnecessary in nondiabetic pregnancies at risk?

For several years standard obstetric practice has been to perform an amniocentesis for evaluation of fetal maturity. In order to provide a more definitive answer as to which pregnancies need an amniocentesis, a group of 294 nondiabetic pregnant women in whom an amniocentesis for the evaluation of fetal maturity had been performed for clinical indications were evaluated. Three predictors of fetal maturity—obstetric estimate of gestational age, fetal biparietal diameter, and ultrasonic determination of placental maturation—were evaluated for their ability to predict three outcomes of fetal maturity, including positive amniotic fluid phosphatidylglycerol, pediatric estimate of gestational age ≥38 weeks, and absence of hyaline membrane disease. A fetal biparietal diameter of ≥90 mm was present in 36% of the total population and was associated with 97% term delivery, 87% positive amniotic fluid phosphatidylglycerol, and 0% hyaline membrane disease. The results associated with an obstetric estimate of gestational age of ≥38 weeks were similar. In the present data set over one third of clinically indicated amniocenteses could potentially be avoided without losing any predictive capability for fetal maturity.

Enzymic colorimetric determination of phosphatidylglycerol in amniotic fluid.

We describe a procedure for the enzymic, colorimetric determination of phosphatidylglycerol in amniotic fluid. After extraction into chloroform:methanol (2:1 by vol) and evaporation, the phospholipid-containing residue is redissolved in a non-ionic detergent, which thus provides an aqueous sample. The subsequent enzymic reaction sequence involves phospholipase-catalyzed hydrolysis of glycerol from its phospholipid. Subsequent enzyme-catalyzed reactions phosphorylate this glycerol and oxidize the resulting glycerol phosphate to produce hydrogen peroxide, which is reacted to produce an intense red chromogen in the peroxidase-catalyzed coupling of 4-aminoantipyrine and 2-hydroxy-3,5-dichlorobenzenesulfonate. When used in conjunction with previously reported enzymic techniques for determination of lecithin and sphingomyelin, this procedure may provide an accurate and precise "lung profile" for assessment of fetal lung maturity.

THE TRACHEAL ASPIRATE LUNG PROFILE

The lecithin/sphingomyelin (L/S) ratio & percent phosphatidyl glycerol (PG) in amniotic fluid are used to evaluate fetal lung maturity, but their value in tracheal aspirates to predict respiratory distress syndrome (RDS) has not been defined. Phospholipid lung profiles on tracheal aspirates within 12 hrs of birth from 551 babies were analyzed by 2-dimensional thin layer chromatography & reflectance densitometry. Infants with respiration, asphyxia, pneumonia, syndromes, chorioamionitis, IUGR, or pulmonary hypoplasia were excluded. Radiologic & clinical criteria were used to classify the remaining patients as RDS (125), retained lung fluid (RLF) (50), or no respiratory disease (60). L/S best predicted RDS (78%) when values were ≤2.6 & identified normals (85%) above 2.6. The mean L/S for RLF (4.06) & normals (4.37) were higher than for RDS (2.3). Accuracy of PG in predicting RDS was best (96%) at trace (<1%) or less, identifying 83% of normals. Seventeen percent of normals & 56% of RLF had <1% PG, while 4% of RDS cases had ≥1% PG. Lung profile values accepted for amniotic fluid seem to overestimate pulmonary maturity when applied to tracheal aspirates. Tracheal aspirate L/S & PG together are highly useful in the biochemical diagnosis of RDS.

Amniotic fluid phosphatidylglycerol and prediction of fetal lung maturity in diabetic pregnancies

SummaryAmniocentesis was carried out in 35 pregnant diabetic patients within 72 hours before delivery. All patients had lecithin/sphingomyelin ratios of 22 or more. Four babies (114 per cent) developed respiratory distress syndrome. The remainder of the same 35 samples of amniotic fluid were used retrospectively to predict fetal lung maturity in two ways using phosphatidylglycerol. Measurement of amniotic fluid phosphatidylcholine (lecithin) and phosphatidylglycerol concentrations appears to predict fetal lung maturity more accurately than either the lecithin/ sphingomyelin ratio alone or when combined with simply recording the presence of phosphatidylglycerol.

Avoiding prematurity in elective repeat cesarean section. A role for amniotic fluid phosphatidylglycerol.

A prospective study was undertaken in 107 elective repeat cesarean deliveries in which the lecithin/sphingomyelin (L/S) ratio was positive. The frequency of neonatal complications in 87 of these women having positive amniotic fluid (AF) phosphatidylglycerol (PG) was compared with the frequency in the remaining 20 patients exhibiting a negative PG. Hyaline membrane disease (HMD) did not occur in either group. However, neonatal complications and related clinical procedures were significantly increased in the PG-negative patients. These neonatal complications included increased frequency of admissions to the neonatal intensive care unit, physiologic jaundice, poor feeding, transient tachypnea, prolonged oxygen therapy, arterial blood gas determinations, chest X-ray and placement of a peripheral intravenous line. The cause of this increased frequency in neonatal complications appears to be mild prematurity in patients exhibiting a positive AF L/S with a negative PG. This study suggests that, in hospitals where PG determinations are available, neonatal complications could be reduced further by awaiting the AF PG result before electively performing a repeat cesarean section.

A new rapid slide agglutination test for amniotic fluid phosphatidylglycerol: Laboratory and clinical correlation

A new rapid slide agglutination test (Amniostat-FLM/AFLM) for amniotic fluid phosphatidylglycerol has been developed. One hundred ninety-three samples of amniotic fluid were tested for lecithin/sphingomyelin (L/S) ratio and phosphatidylglycerol by thin-layer chromatography and fluorescence polarization and compared with the AFLM. All four tests agreed in 123/193 cases. Phosphatidylglycerol and AFLM were concordant in 176/193 cases. From these samples, data were available on 105 neonates, of whom 74 were delivered within 72 hours of amniocentesis. All positive AFLM tests were associated with absence of hyaline membrane disease, of 22 negative tests, eight babies had hyaline membrane disease. Thus, preliminarily, it appears that this is a useful, rapid test for assessing fetal lung maturity, which like other tests is reliable when indicating maturity but has a high incidence of falsely immature results.

Fetal pulmonary maturity: Relationship between optical density (650 nm) to the lecithin/sphingomyelin ratio and phosphatidylglycerol in amniotic fluid

An optical density value ⩾0.15 at A 650 nm of amniotic fluid obtained through transabdominal amniocentesis from a high risk obstetrical population, which excluded diabetes mellitus, isoimmunization, and amniotic fluid infection, correlated 98.6% with a mature lecithin to sphingomyelin ratio ( L S ) ⩾ 2.0% and 41.6% with the presence of phosphatidylglycerol (PG). The corresponding false positive rates were 1.4% and 16.8%, respectively. In 30 infants delivered within 48 h of testing, A 650 nm ⩾0.15 correlated 100% with absence of respiratory distress syndrome. A 650 nm is not recommended for Rhesus immunized gestations, diabetic pregnancies and amniotic fluid infection due to a high false positive rate with A 650 nm compared to L S and PG.