Fluorine-19 magnetic resonance in measurement of the thermodynamics of the reaction of o-alkylphenols with hexafluoroacetone.

The reaction of several o-alkylphenols with hexafluoroacetone at 0-68 degrees was followed by measuring the fluorine magnetic resonance. A knowledge of the equilibrium of the hemiacetal formation is useful in devising schemes for determination of these compounds. The enthalpy and entropy changes for the equilibrium were found to become less negative with increasing size of the ortho-substituents, indicating the importance of steric interaction.

Cholesterol in amniotic fluid, determined by gas chromatography.

Cholesterol was extracted from amniotic fluid, saponified, converted to its trimethylsilyl derivative, and gas chromatographed, with cholesteryl acetate as the internal standard. The method is sufficiently accurate and precise for use with the range of concentrations of cholesterol found in amniotic fluid (5 to 48 mg/litre). Total cholesterol was measured in amniotic fluids collected at different stages of gestation.

Accumulation of glyceryl ether lipids in Wolman's disease.

We have shown that ether-linked glycerolipids accumulated in the adrenal, liver, and spleen of a male Chinese infant with Wolman's disease; the increases were mainly in the alkyl and alk-1-enyl glycerolipids that did not contain phosphorus. Alkyldiacylglycerol accounted for a portion of the rise in the neutral alkylglycerols. The spleen also contained increased amounts of ether-linked phosphoglycerides of the alkyl and alk-1-enyl types.