Postprandial triglyceridemia and 'remnantemia' may better reflect the atherosclerotic risk than triglyceride (TG) levels in the fasting state. Recently, a new method was developed based on a monoclonal antibody recognizing an epitope distal to the carboxyl end of apo B48 which allows easy measurement of remnant-like lipoproteins (RLP). This study was performed in order to investigate RLP response to a standardized fat meal and establish a normal diurnal pattern of RLP in blood and compare it to platelet aggregation and fibrinolysis in healthy young men. We investigated 7 male volunteers (age range 18-23 years) who received a standardized fat meal (Othsuka Pharmaceutical Company, Japan) containing 32.9% lipids, 2.5% protein, 2.5% carbohydrate, 0.3% calcium and 0.1% phospholipids, and 74 mg/100 g cholesterol (C) at 7:30. The energetic value of this cocktail was 341 kcal/100 g. Area under curve (AUC) responses in TG, RLP-TG and RLP-C after the meal were as follows: for TG 28.66 +/- 8.94; for RLP-TG 17.54 +/- 5.55; for RLP-C 1.27 +/- 0.42 mg x dl-1 x h-1. These responses were correlated to each other. Surprisingly, collagen-induced platelet aggregation in whole blood was negatively related to RLP-C AUC. Fluctuation patterns of TG, RLP-TG and RLP-C concentrations during the day were remarkably similar, peaking in this particular group of subjects at 10:00-12:00 and at about 23:00, whereas cholesterol was decreasing late in the night and very early in the morning. This pattern was different from those of platelet aggregation and fibrinolysis parameters.

Adolescent↗

PubMedDate not supplied

Comprehensive study on platelet function, hemostasis, fibrinolysis, peripheral serotonergic system and serum lipids in nephrotic syndrome.

A comprehensive study on platelet aggregation, hemostasis, fibrinolysis and serum lipids in relation to peripheral serotonergic system has been performed on 41 nephrotic patients. Enhanced platelet aggregatory responses in both whole blood and in platelet rich plasma (PRP) were found upon stimulation with different agonists when compared to healthy volunteers. Increased levels of fibrinogen, fibrin monomers, and protein C activity were observed in nephrotic patients. Euglobulin clot lysis time was significantly prolonged in nephrotic patients. Activity of tissue plasminogen activator (tPA) inhibitor was higher in nephrotic syndrome, whereas tPA activity was significantly lower in these patients when compared to controls. Urokinase concentration, lipoprotein (a), cholesterol, LDL and VLDL levels were significantly higher in nephrotic patients over controls. Whole blood serotonin was significantly lower, whereas plasma serotonin was significantly higher in nephrotic patients relative to controls. Serotonin uptake and its release from platelets were markedly diminished in patients with nephrotic syndrome. Disequilibrium in the coagulolytic system, platelet hyperactivity, hyperfibrinogenemia, disturbances in peripheral serotonergic system together with lipid abnormalities may contribute to the progression and development of atherosclerosis and an enhanced risk of thromboembolic complications in nephrotic syndrome.

Adenosine Diphosphate↗

PubMedDate not supplied

Construction, expression and preliminary characterization of glycosylation mutants of human protein S.

Human protein S (HPS) is a vitamin K dependent plasma glycoprotein involved in the regulation of activated protein C and possibly fibrinolysis. Its c-DNA sequence shows three N-glycosylation consensus sequences (Asn-X-Ser/Thr). In order to study influence of N-linked glycosylation on HPS function, set of mutants of HPS was constructed. Mutants were generated, starting from an SV40/Adeno derived pD5HPS2 expression vector, using PCR enabled, site specific methodology. They included single amino acid substitutions at each of three N-glycosylation consensus sequences: Asn458-->Gln, Ser460-->Gly, Asn468-->Gln, Thr470-->Gly, Asn489-->Gln, Thr491-->Gly. Variant HPS were expressed in stable 293 human kidney cell lines in the presence of vitamin K1 (we did not succeed in expressing variant Asn489-->Gln) and purified from conditioned media using pseudoaffinity chromatography on QAE-Sepharose. Variant Asn468-->Gln showed decreased gamma-carboxyglutamate content. All of the mutants were active in a clotting type assay based on factor Va inactivation, and they were compared to wt-HPS and plasma HPS. In conclusion, we have constructed, expressed and purified set of HPS mutants useful in studying the role of N-glycosylation in HPS function.

Base Sequence↗