A. Vecchini, F. Del Rosso, L. Binaglia, N. S. Dhalla and V. Panagia. Molecular Defects in Sarcolemmal Glycerophospholipid Subclasses in Diabetic Cardiomyopathy. Journal of Molecular and Cellular Cardiology (2000)32, 1061–1074. Although still scarcely studied, the phospholipid component of the cell membrane is of absolute importance for cell function. Experimental evidence indicates that individual molecular species of a given phospholipid can influence specific membrane functions. We have examined the changes in molecular species of diacyl and alkenylacyl choline/ethanolamine glycerophospholipid subclasses and those of phosphatidylserine in purified cardiac sarcolemma of healthy and streptozotocin-induced insulin dependent diabetic rats without or with insulin treatment. The relative content of plasmalogens increased in all the phospholipid classes of diabetic sarcolemma under study. Phosphatidylcholine and phosphatidylethanolamine were mostly enriched with molecular species containing linoleic acid in sn -2 position and deprived of the molecular species containing arachidonic acid. The molecular species of phosphatidylserine containing either arachidonic or docosahexaenoic acid were less abundant in membranes from diabetic rats than in membranes from controls. Insulin treatment of diabetic rats restored the species profile of phosphatidylethanolamine and overcorrected the changes in molecular species of phosphatidylcholine. The results suggest that the high sarcolemmal level of plasmalogens and the abnormal molecular species of glycerophospholipids may be critical for the membrane dysfunction and defective contractility of the diabetic heart.

A new model for coalescence and breakage of liquid-liquid dispersion is presented. The main features are: (i) the introduction of an efficiency factor which controls the time rate of the various processes affecting the size distribution function of droplets, (ii) a new effect — that we call volume scattering — which is consistent with the experimentally observed circumstance of the existence of a top size limit for droplets depending on the general dynamical conditions. The model is proved to be mathematically and physically correct by proving existence and uniqueness of a regular solution to the Cauchy problem.

CDP-ethanolamine:diacylglycerol ethanolaminephosphotransferase (EC 2. 7.8.1) has been purified to electrophoretic homogeneity and in a catalytically active form from bovine liver microsomes. The purification method is based on the high hydrophobicity of the protein whose charged sites appear to be masked from the interaction with the chromatographic stationary phases when membranes are solubilized with an excess of non-ionic detergent. The isolated protein has a molecular mass of about 38 kDa, as estimated by SDS-PAGE mobility, and exhibits both ethanolaminephosphotransferase and cholinephosphotransferase activities. Evidence is given that both activities are Mn2+-dependent and that the same catalytic site is involved in cholinephosphotransferase and ethanolaminephosphotransferase reactions. Mg2+-dependent CDP-choline:diacylglycerol cholinephosphotransferase (EC 2.7.8.2) is completely inactivated during the solubilization and purification steps.