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Biomedical subjects

M J Herschel

Publications and source records attributed to M J Herschel.

11 recordsLinked to original sources
PubMed1985

Positive correlation between mature amniotic fluid optical density readings and the absence of neonatal hyaline membrane disease.

Fetal pulmonary maturity is generally determined by analyzing amniotic fluid for surfactants. This task is accomplished by lipid extraction of the fluid and resolution, identification and quantitation of the isolated lipids with thin-layer chromatography. These methods are lengthy, cumbersome and often not available on demand. A quick, simple, reliable and economical test therefore would be highly desirable. We have been able to correlate an optical density (OD) reading of amniotic fluid at 650 nm greater than or equal to 0.15 with the absence of hyaline membrane disease (HMD). For 428 fluids in which an OD reading of greater than or equal to 0.15 was found and delivery occurred within 48 hours, HMD was present in only two infants. The accuracy of the test was 99.53% , with a false-positive rate of 0.47%. With the use of this simple and accurate test one can satisfy the requirement of an on-demand test to determine fetal pulmonary maturity.

Amniotic Fluid↗
PubMed1984

Oxytocin and neonatal hyperbilirubinemia. Studies of bilirubin production.

We studied the effect of oxytocin induction or augmentation of labor on rates of bilirubin production in newborns at three different institutions. Bilirubin production, assessed quantitatively by the pulmonary excretion rate of carbon monoxide or qualitatively by the blood carboxyhemoglobin concentration, was not elevated when compared with appropriately matched control groups. Previous studies have implicated administration of large volumes of electrolyte-free dextrose solutions together with oxytocin as an important factor contributing to hemolysis in the infant. The mothers in our studies received minimal amounts of free water. We conclude that oxytocin induction or augmentation of labor does not result in neonatal hemolysis and subsequent hyperbilirubinemia when it is administered without large volumes of sodium-free intravenous solutions.

Bilirubin↗
PubMed1982

Surfactants, L/S ratio, amniotic fluid optical density and fetal pulmonary maturity.

Optical density readings of amniotic fluids of 0.15 or greater at 650 nm have been noted to correlate with fetal pulmonary maturity. The amniotic fluid absorbance has been shown to be due not only to lecithin and sphingomyelin but also to other surfactants, including phosphatidyl glycerol and inositol. The addition of lecithin and sphingomyelin to previously centrifuged amniotic fluid (i.e., optical) density less than 0.001: L/S ratio, nondetectable) results in an increase in absorbance. At any simulated L/S ratio, the addition of phosphatidyl glycerol and/or phosphatidyl inositol results in a further increase in optical density. It is suggested that optical density readings represent more closely the surfactant composition of amniotic fluid than L/S ratios; therefore, it appears that optical density measurements are a better predictor of fetal pulmonary development than are L/S ratios.

Amniotic Fluid↗
PubMed1981

The effect of cervical/vaginal secretions on measurements of lecithin/sphingomyelin ratio and optical density at 650 nm.

Free-flowing amniotic fluid collected vaginally can be used in a reliable way for determination of fetal pulmonary maturity. Lavaging the vaginal/cervical area with sterile saline and examining the lavage fluid for lecithin/sphingomyelin (L/S) spots showed no detectable spots in the supernatants (one exception) and barely detectable L/S spots in the sediment. Vaginal-cervical saline-wash fluids did not affect fluid L/S ratios. Lavaging the vaginal-cervical area with abdominal amniotic fluid did not affect the L/S ratio of the original amniotic fluid.

Amniotic Fluid↗
PubMed1980

Amniotic fluid optical density and neonatal respiratory outcome.

A simple, rapid, economical, and accurate test to assess fetal pulmonary maturity on a 24-hour basis, 7 days a week, is urgently needed. A 15-minute test has been developed that correlates well with fetal pulmonary maturity. Optical density (OD) readings at 650 nm of greater than or equal to 0.15 in pigment-free, centrifuged (2000 Xg, 10 minutes) amniotic fluids obtained from gestations of 33 to 42 weeks correlate with fetal pulmonary maturity (131 of 131, 100%). When OD readings are less than 0.15 in fluids from gestations of 24 to 40 weeks, and antepartum steroids are utilized, the incidence of respiratory distress syndrome (RDS) is 8.3% (14 of 169). The true false-negative rate in this group is therefore unknown.

Amniotic Fluid↗
PubMed1978

Positive correlation of optical density at 650 nm. with lecithin/sphingomyelin ratios in amniotic fluid.

In this study, we have attempted to correlate optical density measurements of amniotic fluids with L/S ratios. We may conclude, with over a 98 per cent accuracy, that fluids having optical density readings of 0.15 and above, at 650 nm. will have an L/S ratio over 2.0. Fluids having optical density readings up to 0.05 will have L/S ratios of about 1.3. Finally, amniotic fluids having optical densities greater than 0.05 and less than 0.15 will have L/S ratios of approximately 1.5.

Amniotic Fluid↗
PubMed1977

Relation between optical density at 650 nm and L/S ratios.

A simple and rapid test that correlates with L/S ratios has been developed. By centrifuging fresh, unfrozen amniotic fluids at 200g for 10 minutes and measuring the optical density at at 650 nm, correlation with L/S ratios is obtained. Optical density readings of 0.15 or greater correlate 100% with L/S ratios of 2.0 or greater. Optical readings below 0.15 correlate 94% with L/S ratios below 2.0.

Amniotic Fluid↗
PubMed1976

Correlation between amniotic fluid optical density and L/S ratio.

A test that circumvents the complex methodology needed for the determination of L/S ratios has been developed. It has been observed that the optical density, measured at 400 nm, of supernatants collected from fresh amniotic fluids centrifuged at 2000 g for 10 minutes correlates with L/S ratios.

Amniotic Fluid↗