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Biomedical subjects

A Valette

Publications and source records attributed to A Valette.

68 records · Page 4Linked to original sources
PubMed1980

Characterization of triacylglycerol lipase activity in human amniotic fluid.

A radiochemical assay was used to measure the triacylglycerol lipase activity found in normal human amniotic fluid at term. Enzyme activity was characterized in a partially purified extract of amniotic fluid and was found to be optimal at pH 8.0 +/- 0.2 in the presence of 5mM sodium taurocholate, with the use of emulsified tri-[3H]oleoyl glycerol as the substrate. The assay described made it possible to determine the lipase activity in as little as 25 microliters of a 12,000 x g supernatent of whole amniotic fluid as the source of enzyme. The lipase appeared to be distinct from another triacylglycerol lipase measurable in fetal membranes. In turn, it was shown that the amniotic fluid enzyme exhibited several catalytic properties which resembled those of pancreatic lipase. i.e., its substrate specificity, the bimodal effect of bile salt, and the influence of authentic pancreatic colipase on the catalytic process. The results suggest that the assay of triacylglycerol lipase activity may be clinically useful in the detection of enzyme abnormalities in human amniotic fluid.

Amniotic Fluid↗
PubMed1977

Estrogen hormones and lipid metabolism. Effect of ethynyl-estradiol on liver lipases.

Lipase activities assayed in liver subcellular fractions from rats given ethynyl-estradiol are lowered, while triglycerides increase and cholesterol decreases in blood. Triester lipase in microsomes is the most altered activity. Such enzymatic changes might play a role in the development of lipid abnormalities in blood of women taking estrogens as oral contraceptives.

Animals↗
PubMedDate not supplied

Immunoreactive dynorphine in maternal blood, umbilical vein and amniotic fluid.

Immunoreactive dynorphin (ir-Dyn) was measured in maternal blood, umbilical vein and amniotic fluid after its extraction by passage through Sep Pak (C18 Waters). No significant change was observed in the plasma level of ir-Dyn in the first and second trimester of pregnancy as compared with plasma obtained from non-pregnant women. However, a 2.2 fold increase in ir-Dyn levels was observed during the third trimester as well as at delivery (1.07 and 1.09 pmoles per ml, respectively as compared with 0.48 pmoles per ml in control plasma). High levels of ir-Dyn were also found in the amniotic fluid (0.83 pmoles per ml) and the umbilical vein plasma (2.2 pmoles per ml). High pressure liquid chromatography analysis of maternal plasma ir-Dyn obtained at the end of the third trimester of pregnancy revealed the presence of multiple forms of ir-Dyn, the major peaks corresponding to the elution time of some previously identified placental ir-compounds namely Dyn-(1-11) and Dyn-(1-13). These data indicate that the levels of ir-Dyn in the maternal plasma at the third trimester of pregnancy and at delivery increase, a placental contribution to this phenomenon could be speculated.

Amniotic Fluid↗