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J C Dohnal

Publications and source records attributed to J C Dohnal.

5 recordsLinked to original sources
PubMed1991

Lamellar body number density and the prediction of respiratory distress.

The determination of amniotic fluid lamellar body number density (LBND) has recently been shown to correlate well with other established indicators of fetal lung maturity. The authors have compared the LBND with a fetal lung phospholipid profile in predicting the clinical outcome in 52 well-documented cases. If a cutoff of 30,000/microL was used to indicate fetal lung maturity, there were no false-negative results for the LBND whereas there was one for the fetal lung profile. On the other hand, this cutoff resulted in 22 false-positive results for the LBND, whereas there were only 7 false-positive results by the fetal lung profile. The number of false-positive results by the LBND can be decreased by using a separate cutoff of less than 10,000/microL to indicate high risk for development of respiratory distress, while leaving the cutoff for predicting mature lung at 30,000/microL. This resulted in only four false-positive results for the LBND; each of these were from the same patients who also had false-positive results by the fetal lung profile. Care must be taken to ensure that the particle counter used is properly calibrated and that the appropriate cutoffs for both lung maturity and immaturity are used.

Amniotic Fluid↗
PubMed1986

Degree of unsaturation of the fatty acid chains of phospholipids influences the fluorescence polarization: implications for evaluating fetal lung maturity.

To study the effect of fatty acid chain saturation on the fluorescence polarization assay as a measure of fetal lung maturity, we used purified phospholipids isolated from human amniotic fluid and various commercial phospholipids. We found that the fluorescence polarization value decreased as the concentration of unsaturated fatty acids increased. In contrast, the lecithin/sphingomyelin ratio increases with increasing amounts of saturated lecithin, produced as the fetal lung matures. Since only saturated lecithins are surface active, the two indices of fetal respiratory status must reflect different properties of lung surfactant.

Amniotic Fluid↗
PubMed1979

The interaction of dodecyl and tetradecyl sulfate with proteins during polyacrylamide gel electrophoresis.

1. The affinity of tetradecyl sulfate for many unfolded proteins is greater than that of dodecyl sulfate. 2. It is the presence of tetradecyl sulfate that results in the staining of proteins by pinacryptol yellow seen by Stoklosa and Latz (Stoklosa, J.T. and Latz, H.W. (1974) Biochem. Biophys. Res. Commun. 58, 74--79), as some tetradecyl sulfate remains associated with proteins during electrophoresis at room temperature (as opposed to dodecyl sulfate which, within the limit of detection, is completely removed). 3. Tetradecyl sulfate has a greater capacity to dissociate protein aggregates which consist of identical peptide chains, such as Glycophorin dimers and bovine serum albumin dimers, than does dodecyl sulfate.

Chemical Phenomena↗
PubMedDate not supplied

Functional phospholipid/sphingomyelin ratio: an easy to interpret indicator of fetal lung maturity.

Data are presented which show that the functional phospholipid/sphingomyelin (FPL/S) ratio is a sensitive and specific prenatal indicator of fetal respiratory status. Phospholipids included in the ratio are acetone precipitable lecithin(L), phosphatidylglycerol(PG), phosphatidylethanolamine(PE), and sphingomyelin(S). These lipids have been shown to contribute to either the lowering of surface tension or to changes in microviscosity. Both of these properties contribute independently to the physiologic effectiveness of fetal lung surfactant. Although other phospholipid profiles have been described in the literature, the FPL/S ratio accounts for the major phospholipids which contribute to lung surfactant function with the added advantage of presenting the data in the form of a single easy to interpret number. Clinical correlates are also presented for the L/S ratio, fluorescence polarization assay (using 1,6-diphenyl-3,5-hexatriene), and absorbance at 650 nanometers.

Amniotic Fluid↗