[Dyslipidemic patients with coronary cardiopathy. Effect of different doses of OMEGA-3 fatty acids on serum lipids and lipoproteins]

Twenty one male patients aged 35 to 70 years, with coronary artery disease and dislipidemia refractory to dietary treatment, were assigned to three parallel groups of 7 individuals each that received a supplemental dose of 2, 4 and 6 g/day of omega-3 fatty acids during 60 days. After a 30 days wash-out period and 60 of supplementation, subjects were weighed, a dietary survey was performed, serum levels of total cholesterol and triglycerides, the lipid content of serum lipoproteins and the content of EPA+DHA in plasma phospholipids were measured. A dose dependent increase in EPA+DHA content of phospholipids and no changes in weight or nutrient intake were observed during the supplementation period. With the 6 g dose, a significant reduction in total cholesterol, with a reduction in VLDL and increase in LDL cholesterol and a decline in VLDL triglycerides was observed. With the 4 g dose a reduction in total cholesterol at the expense of VLDL and HDL cholesterol and a reduction in VLDL triglycerides but no changes in total triglycerides was observed. No changes in serum lipids were observed with 2 g dose. In patients with type IIA hyperlipidemia, a significant positive correlation was observed between DHA+EPA content of plasma phospholipids and LDL cholesterol, this correlation was not observed in patients with IIB or IV phenotypes. It is concluded that omega-3 fatty acids are ineffective as the only treatment for dislipidemias refractory to diet.

Pig liver phosphomevalone kinase. 1. Purification and properties

Pig liver phosphomevalonate kinase (EC 2.7.4.2) has been purified to homogeneity as shown by polyacrylamide gel electrophoresis. The molecular weight estimates range from 21,000 to 22,500. Each molecule is composed of one polypeptide chain. The presence of SH-containing reagents is essential for the preservation of enzymes activity at all steps in the purification. The enzyme shows absolute specificity for ATP and requires for activity a divalent metal cation, Mg2+ being most effective. The optimum pH for the enzyme ranges from 7.5 to over 9.5. Kinetics are hyperbolic for both substrates, showing a sequential mechanism; true Km values of 0.075 mM and 0.46 mM have been obtained for phosphomevalonate and ATP, respectively. Amino acid composition shows a high content of acid amino acids, one cysteine residue per molecule of enzyme, and the absence of methionine. The results obtained suggest that the enzyme plays no regulatory function in cholesterol biosynthesis in pig liver, although a variable enzyme content was detected in different livers.