diphenylhexatriene and Respiratory-Distress-Syndrome--Newborn

A rapid (30-min) semiautomated continuous-flow procedure is described for use in assessing the phospholipids of the particulate ("lamellar body") fraction of human amniotic fluid. The method is based on measuring the difference in fluorescence of 1,6,-diphenyl-1,3,5-hexatriene added to amniotic fluid before and after micropore filtration. The filtration step removes "lamellar body" particles, which are considered to contain the fetal lung surfactant. The phospholipid values for the filtered particles are independent of background fluorescence, which increases when amniotic fluid is contaminated by bilirubin pigments or blood components. Over a wide range (3-150 mumols/L) the fluorescence increases linearly with the phospholipid concentration of the amniotic fluid. There is a good agreement between the value for particulate "lamellar body" phospholipid, the ratio of the "lamellar body" phospholipids to total amniotic fluid phospholipids, and the lecithin/sphingomyelin ratio.

Topics: Amniotic Fluid; Autoanalysis; Diphenylhexatriene; Female; Fluorometry; Humans; Infant, Newborn; Phosphatidylcholines; Phospholipids; Pregnancy; Prenatal Diagnosis; Pulmonary Surfactants; Respiratory Distress Syndrome, Newborn; Sphingomyelins; Ultrafiltration

The steady-state polarization (or anisotropy) of the fluorescent dye 1,6-diphenyl-1,3-5-hexatriene in amniotic fluid samples and the lecithin/sphingomyelin ratio of the samples were correlated with development of respiratory distress syndrome in newborns. We found that clinical samples have a variable endogenous fluorescence that reduces the observed polarization (or anisotropy). This background is a major interference in the assessment of fetal lung maturity by the polarization method. Correction for this interference, by also measuring the blank fluorescence and anisotropy of the sample, provides a clinical tool with a lower coefficient of variation than that of the more time-consuming lecithin/sphingomyelin ratio. The clinical correlation for 17 cases of respiratory distress syndrome in a high-risk population (60 births; twins counted as a single birth) indicates that the two methods are equivalent for predicting immature fetal lung status.

Topics: Amniotic Fluid; Diphenylhexatriene; Evaluation Studies as Topic; Female; Fetal Organ Maturity; Fluorescence Polarization; Humans; Infant, Newborn; Lung; Phosphatidylcholines; Pregnancy; Prenatal Diagnosis; Respiratory Distress Syndrome, Newborn; Sphingomyelins

Topics: Amniotic Fluid; Diphenylhexatriene; Female; Fetus; Humans; Infant, Newborn; Lung; Phosphatidylcholines; Pregnancy; Prenatal Diagnosis; Respiratory Distress Syndrome, Newborn; Spectrometry, Fluorescence; Sphingomyelins

Fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene in amniotic fluid lipid aggregates was measured to determine the ability of this technique to prospectively predict respiratory distress syndrome. Prior retrospective studies have shown that an FP value of less than or equal to 0.336 correlated best with a lecithin to sphingomyelin ratio of greater than 2.0. Fluorescence polarization values of amniotic fluid samples obtained within 48 hours of birth from 161 pregnancies were correlated with neonatal outcome. Samples from 149 pregnancies had FP values of less than or equal to 0.336 and samples from 12 pregnancies had FP values of greater than or equal to 0.336. No infants delivered from the former group developed RDS and eight of 12 infants from the latter group developed RDS (P less than 0.001). In the entire population the test had a sensitivity of 100% and a specificity of 97%. When 37 infants with birth weights less than 2,500 gm were studied, the FP value remained a highly reliable predictor of the infant at risk for developing RDS (P less than 0.001). In this subset the test had a sensitivity of 100% and a specificity of 90%. L-S ratios were performed on 96 samples and the results correlated well with FP values (P less than 0.001). We conclude that the amniotic fluid FP value is a reliable index of fetal lung maturity and the risk for developing RDS. The FP value also has specific technical and diagnostic advantages over the L-S ratio.

Topics: Amniotic Fluid; Diphenylhexatriene; Evaluation Studies as Topic; Female; Fluorescence Polarization; Humans; Infant, Newborn; Phosphatidylcholines; Polyenes; Pregnancy; Probability; Respiratory Distress Syndrome, Newborn; Risk; Sphingomyelins