[Coagulation activity of circulating membrane microparticles in patients with cardiovascular diseases].

Membrane microparticles (MP) are released by activated or damaged cells and are able to accelerate blood clotting (coagulation). MP possess coagulation activity since all of them contain on their surface phosphatidylserine (PS), a substrate for the assembly of coagulation complexes, and some of them tissue factor (TF), the primary initiator of coagulation cascade reactions. We compared the coagulation activity and amount of MP in the blood of healthy donors (n=34) and patients with myocardial infarction (MI) (n=32), advanced atherosclerosis (AA) (n=32) and idiopathic pulmonary arterial hypertension (IPAH) (n=19).

[Coagulation properties of erythrocyte derived membrane microparticles].

Membrane microparticles (MP) produced upon cell activation and/or damage possess coagulation activity, i.e. ability to accelerate blood clotting.

Differential procoagulant activity of microparticles derived from monocytes, granulocytes, platelets and endothelial cells: impact of active tissue factor.

: Microparticles released by activated/apoptotic cells exhibit coagulation activity as they express phosphatidylserine and some of them - tissue factor. We compared procoagulant properties of microparticles from monocytes, granulocytes, platelets and endothelial cells and assessed the impact of tissue factor in observed differences. Microparticles were sedimented (20 000g, 30 min) from the supernatants of activated monocytes, monocytic THP-1 cells, granulocytes, platelets and endothelial cells.

Activity of Tissue Factor in Microparticles Produced in vitro by Endothelial Cells, Monocytes, Granulocytes, and Platelets.

Activity of tissue factor (TF) in membrane microparticles (MPs) produced in vitro by endothelial cells (ECs), monocytes, THP-1 monocytic cells, granulocytes, and platelets was investigated. ECs were isolated from human umbilical vein, and monocytes, granulocytes, and platelets - from the blood of healthy donors. ECs, monocytes, and THP-1 cells were activated by bacterial lipopolysaccharide, granulocytes - by lipopolysaccharide or phorbol myristate acetate, and platelets - by SFLLRN, thrombin receptor-activating peptide.

Study of the Structure, Oxygen-Transporting Functions, and Ionic Composition of Erythrocytes at Vascular Diseases.

The present paper explores the role of erythrocytes in the pathogenesis of vascular diseases. The state of erythrocytes, their ionic composition and structure, and properties of erythrocytes hemoglobin were studied by using laser interference microscopy, Raman scattering spectroscopy, and capillary electrophoresis. In patients suffering from vascular disorders we identified statistically significant changes in the shape of erythrocytes, their ionic composition, and redistribution of hemoglobin throughout cells.

Relationships of glycoproteins IIb-IIIa and Ib content with mean platelet volume and their genetic polymorphisms.

Quantity of platelet adhesion molecules significantly varies in normal donors and cardiovascular patients and might be affected by platelet size and genetic variations. In this study, we assessed relationships of the content of glycoprotein (GP) IIb-IIIa and GPIb with mean platelet volume (MPV) and their genetic polymorphisms. MPV and GPIIb-IIIa and GPIb numbers were measured in 116 patients with acute coronary syndrome (ACS) at days 1, 3-5 and 8-12 after disease onset and in 32 healthy volunteers.

Spontaneous platelet aggregation in patients with acute coronary syndrome.

Spontaneous platelet aggregation was evaluated in patients with acute coronary syndrome on days 1, 3-5, and 8-12 of the disease. On day 1, aggregation was analyzed after aspirin, but before clopidogrel administration; during other periods after both antiaggregants. The mean levels of spontaneous aggregation after antithrombotic therapy did not change during different periods after the onset of acute coronary syndrome, in contrast to ADP-induced aggregation that decreased after the development of clopidogrel effects (days 3-5 and 8-12).

Glycoprotein IIb-IIIa content and platelet aggregation in healthy volunteers and patients with acute coronary syndrome.

Glycoprotein (GP) IIb-IIIa (αIIbβ3-integrin) is the central receptor of platelet aggregation. Activated GP IIb-IIIa binds fibrinogen or von Willebrand factor, which forms molecular bridges between aggregating platelets. This review summarizes data on the relationship between GP IIb-IIIa expression on the platelet surface and platelet aggregating activity.

The composition, structural properties and binding of very-low-density and low-density lipoproteins to the LDL receptor in normo- and hypertriglyceridemia: relation to the apolipoprotein E phenotype.

The composition, apolipoprotein structure and lipoprotein binding to the LDL receptor were studied for very-low-density (VLDL) and low-density lipoprotein (LDL) particles isolated from subjects with apoE phenotype E3/3 (E3), E2/2 or E2/3 (E2+) and E3/4 or E4/4 (E4+) and a wide range of plasma triglyceride (TG) contents. The data combined for all three phenotype groups can be summarized as follows. (i) A decrease in accessibility of VLDL tryptophan residues to I- anions with a decrease in tryptophan surface density, concomitant with an increase in VLDL dimensions, reflects the increased efficiency of protein-protein interactions.

Structural peculiarities of the binding of very low density lipoproteins and low density lipoproteins to the LDL receptor in hypertriglyceridemia: role of apolipoprotein E.

Very low (VLDL) and low density lipoproteins (LDL) were isolated from plasma of patients with the E3/3 phenotype which were divided into three groups based on their plasma triglyceride content: low (TG<200 mg/dl, TG(l)), intermediate (200<300 mg/dl, TG(i)300 mg/dl, TG(h)). The protein density (PD) on the VLDL and LDL surface was calculated from lipoprotein composition and protein location was studied by tryptophan fluorescence quenching by I(-) anions at 25 degrees C and 40 degrees C. A comparison of the TG(h) with the TG(l) group revealed a significant (<0.

Conformation of apolipoprotein E both in free and in lipid-bound form may determine the avidity of triglyceride-rich lipoproteins to the LDL receptor: structural and kinetic study.

Slow refolding of human apolipoprotein E (apoE) in solution after guanidine- or cholate-induced denaturation followed by dialysis under controlled conditions was investigated using various spectroscopic properties of fluorescein- and dansyl-labeled apolipoprotein molecules. The results suggest that the last phase(s) of apoE refolding in solution include a slow (several hours at 24 degrees C) interconversion of a self-associated 'open' conformer into a more dense 'closed' conformer. The hydrophobic interactions are primarily responsible for the formation of this more compact apoE structure.

Immunoreactivity of apolipoprotein B-100 and binding to LDL-receptor of phospholipase A2-treated low density lipoproteins.

Lipid--protein particles were obtained by treatment of low density lipoproteins (LDL) with phospholipase A2 from bee venom. Under these conditions, half of the phosphatidylcholine (PC) of LDL was changed to lysophosphatidylcholine (LPC). At the same time, the composition of other lipids and the apoprotein structure were unaffected.

Binding of apoB-containing lipoproteins from unfractionated human blood sera to immobilized LDL receptor.

Binding of apoB-containing lipoproteins from unfractionated human blood sera to the immobilized bovine receptor of low density lipoproteins (LDL receptor) was studied. Peroxidase-labeled anti-human apoB antibodies were used to evaluate the lipoprotein binding. The equilibrium dissociation constant (Kd) of the interaction between apoB-containing lipoproteins from unfractionated human sera from healthy donors and the immobilized LDL receptor varied from 1 to 20 microg apoB/ml.

Immunoenzyme assessment of human apoB-lipoprotein binding to immobilized receptor of low density lipoproteins. 2. Binding of isolated lipoproteins.

The receptor of low density lipoproteins (LDL-receptor) from bovine adrenal cortex membranes was immobilized in standard 96-well polystyrene plates using monoclonal V5-antibodies to the LDL-receptor. The binding of the immobilized LDL-receptor with human low density lipoproteins (LDL) and very low density lipoproteins (VLDL) was determined using peroxidase-labelled antibodies to human apoB. The value of Kd for the interaction of LDL with the immobilized LDL-receptor for 40 samples of LDL was found to be from 5 to 20 micrograms apoB per ml.

Immunoenzyme assessment of human apoB-lipoprotein binding to immobilized receptor of low density lipoproteins. 1. Preparation of anti-receptor monoclonal antibodies.

The preparation and properties of V5 monoclonal antibody to low density lipoprotein receptor (LDL-receptor) from bovine adrenal cortex membranes are described. The monospecific V5 antibody recognizes the LDL-receptor (the only protein with molecular mass of 140 kD) in bovine adrenal cortex membranes. V5 antibody fails to compete with human low density lipoproteins (LDL) for binding to the LDL-receptor.

Use of cell culture for optimisation of direct antiatherogenic therapy with verapamil.

The potential of verapamil to prevent atherogenesis induced by atherogenic serum in cell culture was investigated. Smooth muscle cells were cultured from human aortic intima and incubated with blood serum from patients with coronary artery disease. Only serum causing a significant rise in total cholesterol content in cultured cells during a 24-hour incubation period was used.