Platelet factor-3 activity and availability, platelet phospholipids and their fatty acid and aldehyde composition were examined in patients with juvenile diabetes of long duration and in patients with maturity onset diabetes. Increased coagulant activity was found in platelet rich and platelet poor plasma from patients with juvenile diabetes, whereas plasma from patients with maturity onset diabetes reacted as the control group. Platelet rich plasma exposed to ADP, kaolin or freezing and thawing three times reacted not significantly differently from the controls. Increased amount of lipid-P was present in platelets from both patient groups. In patients with juvenile diabetes the increase was mainly caused by an increase of serine phos-phoglycerides and in the other patient group all main phos-pholipid fractions were increased. The phospholipid/protein ratio of platelets was not significantly different in the three groups. Only moderate changes were observed in the fatty acid pattern of the various phospholipids.

Abstract. Two groups, each of 10 subjects, have been given isocaloric diets for 21 days. The diets were identical with the exception of their fat content. One group was given 40% of the calories as soybean oil, and the other the same amount as MCT oil. Platelet and serum lipids and platelet function tests were evaluated before and after the dietary period. The platelet lipid analysis included estimation of total cholesterol and phospholipids, fractionation of phospholipids by thin layer chromatography and gas liquid chromatographic estimation of the fatty acid and aldehyde composition of the various phospholipids. Platelet function tests included platelet factor‐3 (PF‐3) activity and availability, platelet aggregation induced by collagen, ADP and thrombin and platelet electrophoresis. In subjects given a soybean oil diet a significant reduction in serum total cholesterol and phospholipids occurred. No changes were observed in the platelet cholesterol and phospholipid levels, whereas a significant increase of linoleic acid in choline, ethanolamine and serine phosphoglycerides took place. The relative increase of linoleic acid was most marked in the choline phosphoglycerides. A moderate decrease in palmitic and oleic acids was seen in most phospholipid fractions. PF‐3 activity in platelet‐rich plasma showed a consistent decrease in these subjects, whereas the other platelet function tests showed insignificant changes. In subjects given MCT oil diet no significant changes were observed in serum or platelet lipids, including the phospholipid fatty acids. Increased PF‐3 activity in platelet‐rich plasma exposed to ADP was the only functional disturbance observed in this group.

Abstract. Platelet factor‐3 activity and availability, platelet phospholipids, their fatty acid and aldehyde composition and plasma lipids have been examined in patients with hyperbetalipoproteinemia before and after treatment with nicotinic acid or clofibrate. Increased platelet factor‐3 activity was present in platelet‐rich plasma, and increased availability was found after exposure of platelets to adenosine diphosphate. Estimated per 109 platelets, increased amounts of platelet phospholipids were found in the patients, whereas the phospholipid fatty acid pattern was as in normals. After treatment with nicotinic acid and also clofibrate, the platelet factor‐3 activity and availability were normalized. No changes were observed in platelet factor‐3 activity in platelet‐poor plasma or in the quantity of platelet phospholipids and their fatty acids during the treatment. Plasma cholesterol and phospholipids were markedly decreased by the treatment. It is suggested that an interaction exists between platelets and plasma lipoproteins. In patients with hyperbetalipoproteinemia this interaction may favour the tendency to thrombosis and can be reversed by treatment with nicotinic acid and probably clofibrate.

Abstract. Platelet factor‐3 activity and availability, platelet phospholipids and their fatty acid and aldehyde composition have been examined in males with non‐acute ischemic heart disease and in a control group. Increased platelet factor‐3 activity was present in platelet‐rich but not in platelet‐poor plasma from the patients. No difference in the increase of activity after exposure of PRP to ADP, kaolin or freezing and thawing three times was observed compared with the controls. Estimated per 10° platelets, increased amounts of ethanolamine glycerides, serine phosphoglycerides, choline phosphoglycerides, sphingomyeline and total lipid phosphorus were found in the patient group. The phospholipid: protein ratio was also increased. Only small changes were observed in the fatty acid pattern of the various phospholipids. A slight decrease in palmitic acid and a slight increase in oleic acid were found in most fractions.