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D O Gebhardt

Publications and source records attributed to D O Gebhardt.

At least 55 records · Page 3Linked to original sources
PubMed1982

Comparison of the values for filter-trapped phospholipids with those for the lecithin/sphingomyelin ratio of amniotic fluid. A preliminary report.

A comparison was made between the lecithin/sphingomyelin ratio of amniotic fluid and the amount of phospholipids which could be removed from the amniotic fluid by filtration. We found a good correlation between the two methods. The amount of filter-trapped phospholipids can be determined within one and a half hours compared to three and a half hours for the lecithin/sphingomyelin ratio. It has a higher reproducibility than the lecithin/sphingomyelin ratio and can be performed with the aid of a simple filtration apparatus.

Amniotic Fluid↗
PubMed1979

The lipoprotein composition of amniotic fluid.

The lipoprotein composition of amniotic fluid (AF) has been studied and it was found that it consists of high density lipoprotein (HDL) only. At about the 26th week of pregnancy the HDL content reaches a maximum and decreases thereafter. On crossed immunoelectrophoresis the HDL of AF was separated into two components if the agar layer contained an antiserum against apolipoprotein A-I. The component with the higher electrophoretic mobility (but not the slower moving component) could also be visualized with an antiserum against HDL. When maternal or umbilical cord serum (UCS) was analysed by crossed immunoelectrophoresis using the anti-apoA-I antiserum, we found that they only contained the faster moving lipoprotein component. If UCS was treated with phospholipase A2 and then subjected to crossed immunoelectrophoresis, the slower moving component appeared at the expense of the faster one. Likewise when UCS was incubated with AF from the 15th week of pregnancy or later, the lipoprotein component of UCS with the high mobility was partially converted to the component with the slower mobility. It is concluded that AF probably contains a phospholipase, an enzyme which may promote the onset of labour.

Amniotic Fluid↗
PubMed1978

A rapid semi-automated method of determining total estrogens in non-pregnancy urine.

A rapid routine method of determining estrogens in non-pregnancy urine is described. It involves the following steps: 1) Dilution of each urine sample with an equal volume of saturated ammonium sulfate solution; 2) Addition of Sephadex G-15 beads; 3) Filtration of the mixture; 4) Liberation of the estrogens from the Sephadex by washing the beads on the filter with 0.1N NaOH; 5) Automated fluorimetric analysis of the alkaline filtrate according to the procedure used for the determination of estrogen in pregnancy urine. A correction for non-specific fluorescence remains necessary and is achieved by measuring background fluorescence with a second fluorimeter.

Chromatography, Gel↗
PubMed1975

A study of the lecithin/sphingomyelin ratio of amniotic fluid.

1. There is a significant correlation between lecithin/sphingomyelin (L/S) ratios based on densitometry (L/S)D and L/S ratios based on phosphorus determinations ((L/S)P). 2. The fetal lung is mature when the (L/S)D, determined according to Verhoeven, A.G.J. and Merkus, H.M.W.M. (1974) Clin. Chim. Acta 53, 229--232, is 1.2. This value is equivalent to an (L/S)P of 1.8. 3. The acetone precipitation procedure, introduced by Gluck, L., Kulovich, M.V., Borer, R.C. and Keidel, W.N. (1974) Am. J. Obstet. Gynecol. 120, 142--155, is a necessary step for isolating surface-active lecithin. 4. Standardization of the (L/S)D test is feasible and should permit different laboratories to use the same transition point.

Amniotic Fluid↗
PubMed1975

A comparison between the lecithin/sphingomyelin ratio of Gluck and other phospholipid values of amniotic fluid.

We have found the lecithin/sphingomyelin ratio of Gluck (L/S ratio) to be very useful for predicting respiratory distress. It correlated reasonably well with three other phospholipid values: the total lecithin content, the acetone-insoluble lecithin content, and the total lecithin/total phospholipids ratio. When the L/S ratio of amniotic fluid was greater than 2.0 there was no respiratory distress, even if the other phospholipid values indicated that the fetal lungs were still immature.

Acetone↗