Multiply modified desialylated low-density lipoproteins: Physicochemical properties

Sialylated and desialylated low-density lipoproteins from human blood are shown to differ markedly in physicochemical parameters. The latter lipoproteins have a smaller particle size, are denser and more electronegative, and tend to aggregate more readily than the former. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 121, N ^o 1, pp. 42–43, January, 1996 Presented by E. I. Chazov, Member of the Russian Academy of Sciences     

Lipid composition of multiple modified (desialylated) low-density lipoproteins

It is shown that the lipid composition of desialylated low-density lipoproteins differs considerably from that of native (sialylated) lipoproteins. Desialylated lipoproteins have a lower content of fat-soluble vitamins and a higherin vitro oxidizability. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 122, No. 7, pp. 37–39, July, 1996     

Interaction between multiply modified (desialylated) low-density lipoproteins isolated from blood of atherosclerotic patients and cell receptors

It is shown that binding of native LDL to fibroblasts expressing the B,E-receptors is twice as high as that of desialylated LDL. An excess of acetylated LDL inhibits binding, uptake, and degradation of¹²⁵I-desialylated LDL by macrophages, while an excess of desialylated LDL inhibits binding, uptake, and degradation of acetylated LDL. Desialylated LDL may interact with both B,E and scavenger receptors. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 117, N ^o 1, pp. 53–55, January, 1994     

Effects of low-density lipoproteins on blood coagulation and fibrinolytic activity

In vitro experiments showed that copper-oxidized low-density lipoproteins activate factors of the prothrombin complex in the whole blood and inhibit fibrin generation in both blood and plasma. Moreover, oxidized low-density lipoproteins inhibit fibrinolysis and impair the structure of fibrin clot, which results in hypercoagulation. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 129, No. 6, pp. 637–639, June, 2000     

Effect of high-density lipoproteins on ADP-induced platelet aggregation in plasma

Autooxidized high-density lipoproteins (HDL₂) inhibit ADP-induced platelet aggregation in platelet-rich plasma. Platelet aggregation in the presence of native HDL₂ and HDL₃ and autooxidized HDL₃ does not differ from the control (plasma with buffer). A conclusion is made on the important role of autooxidized HDL₂ as a thrombogenesis-inhibiting factor in atherosclerosis. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 126, No. 8, pp. 160–163, August, 1998     

Interaction of low-density lipoproteins and elastins from the intima and media of human intact and atherosclerotic aorta

Binding of low-density lipoproteins to elastins from the media and proteoglycan and muscle sublayers of human intact and atherosclerotic aorta was studied. Circulating modified lowdensity lipoproteins intensively bound to elastin due to the loss of sialic acid. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 129, No. 2, pp. 180–182, February, 2000     

Multiple modifications of low-density lipoproteins in the blood of patients with atherosclerosis

Atherogenic low-density proteins (LDL) found in human blood — desialylated, electronegative, and small dense LDL — share many chemical and physical characteristics and appear to represent the same subfraction of multiply modified lipoproteins. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 120, N ^o 8, pp. 118–121, August, 1995 Presented by D. S. Sarkisov, Member of the Russian Academy of Medical Sciences     

Effects of native and oxidized low-density lipoproteins on macrophage chemiluminescence

Effects of low-density lipoproteins (LDL) obtained from healthy donors and patients with hypercholesterolemia on spontaneous luminol-dependent and zymosan-induced chemiluminescence of rat macrophages were studied. Unlike LDL from healthy donors, native LDL from patients with hypercholesterolemia inhibited spontaneous chemiluminescence of macrophages. Simultaneous incubation with endotheliocytes from the umbilical vein led to the appearance of inhibitory effect of LDL from healthy donors (incubation for 24 h) and potentiated this effect of LDL from patients with hypercholesterolemia (incubation for 6 and 24 h). The inhibitory effect was more pronounced in LDL incubated with umbilical endotheliocytes under ischemic conditions then after aerobic incubations. This corresponded to higher oxidation of LDL confirmed by accumulation of thiobarbituric acid-reactive substances, increased fluorescence, and high electrophoretic mobility in agarose gel. These data suggest that the model system of spontaneous and zymosan-induced chemiluminescence of macrophages can be used for evaluating the degree of oxidation and potential atherogenicity of LDL. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 128, No. 11, pp. 514–517, November, 1999     

Effect of natural polyphenol compounds on oxidative modification of low-density lipoproteins

Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 116, N ^o 10, pp. 393–395, October, 1993     

Cytotoxic effect of low-density lipoproteins on intact, ischemic, and reperfused endothelial cells

The cytotoxic effect of low-density lipoproteins on cultured human umbilical vein endothelial cells increases with their concentration, degree of oxidation, and incubation time, being more pronounced in ischemia or ischemia+reperfusion than in aerobic conditions. Synergism of the cytotoxic effect of lipoproteins with the damaging effect of ischemia and reperfusion promotes the development of atherosclerotic lesions of the vascular wall at sites predisposed to the damage by the ischemia/reperfusion. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 126, No. 9, pp. 302–306, September, 1998     

Endothelial cells induce oxidation of low-density lipoproteins

The ability of human umbilical vein endothelial cells to oxidize low-density lipoproteins during a 24-h incubation was assessed from the accumulation of products reacting with 2-thiobarbituric acid and fluorescent products in the incubation medium. It depends on the concentration of lipoproteins and the incubation conditions and increases in the following series: aerobic conditions<ischemia<ischemia+reperfusion. This indicates that ischemia and reperfusion of vascular endothelium may promote parietal oxidation of lowdensity lipoproteins and selective atherosclerotic damage to the vascular wall. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 126, No. 9, pp. 314–317, September, 1998     

Induction of immune response to plasma lipoproteins with C-reactive protein

Purified C-reactive protein induces the production of autoantibodies to lipoprotein B-containing lipoproteins in animals. This is due to a C-reactive protein idiotype that permits the, interference of C-reactive protein in the idiotype-anti-idiotypical immunological reactions and stimulation of autoimmune response to lipoproteins. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 126, No. 7, pp. 76–79, July, 1998     

Changes in platelet aggregability after blood irradiation by helium-neon laser and red light emitting diodes

We analyzed changes in platelet aggregability induced by therapeutic irradiation of the blood with red light from a helium-neon laser and light-emitting diodes. Blood irradiation by helium-neon laser or red light-emitting diodes is alternative procedure for the inhibition of platelet functions, particularly in the case of individual intolerance to certain drugs. Translated from Byulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 126, N 12, pp. 645–648, December, 1998     

Correlation between the inhibition of phosphorylation in platelet myosin light chains and the inhibition of platelet aggregation by a new calcium and calmodulin antagonist

The recently synthesized compound [1,2,5-trimethyl-4-phenyl-4-β-(N-methyl-N-4′-methoxybenzyl)-ethylamino]piperidine dihydrochloride (AR-3), which is a derivative of [1,2,5-trimethyl-4-phenyl-4-β-(N,N-disubstituted-ethylamino)]piperidines, was tested for its effects on platelet aggregation and phosphorylation of light myosin chains isolated from platelets. AR-3 caused 50% inhibition of platelet aggregation in concentrations of 25.5 to 32.2 μM (depending on the aggregation inducer used) and 50% inhibition of light myosin chain phosphorylation in a concentration of 70 μM or, when 1 μM calmodulin was added, 120 μM. The good correlation found between the inhibitory effects of AR-3 on platelet aggregation and the phosphorylation of light myosin chains from platelets indicates that this compound inhibits platelet aggregation largely by inhibiting the Ca²⁺-calmodulin-dependent phosphorylation of platelet myosin light chains, acting in this respect similarly to the well-known calmodulin antagonist W-7. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 122, No. 7, pp. 40–42, July, 1996     

Effect of a micellar preparation of polyunsaturated phosphatidylcholine on platelet aggregationin vitro

Platelet aggregation was studied after incubation of cells with polyunsaturated phosphatidylcholine in platelet-rich plasma from healthy donors and coronary patients. The aggregation capacity of cells was found to be reduced after preincubation with the above drug. Statistical processing of the results using Student's and Van der Varden's tests showed more expressed effects of polyunsaturated phosphatidylcholine on cell aggregation in coronary patients than in donors. Translated fromByulleten's Eksperimental'noi Biologii i Meditsiny, Vol. 121, N ^o 2, pp. 199–203, February, 1996 Presented by Yu. M. Lopukhin, Member of the Russian Academy of Medical Sciences     

Effect of allicor on platelet aggregationin vitro andex vivo

An extract of garlic powder in isotonic phosphate buffer and adjoen (bioactive compound isolated from garlic powder) suppress human blood platelet aggregation induced by ADP and arachidonic acidin vitro. Adjoen more effectively than aspirin inhibits ADP-induced platelet aggregation but is inferior to aspirin if platelet aggregation is induced by arachidonic acid.Ex vivo oral intake of one Allicor tablet significantly decreases rabbit platelet aggregation induced with ADP. It is suggested that long-acting garlic powder tablets prevent thromboembolic complications and are recommended for correcting hemostasis parameters in patients with atherosclerotic involvement of blood vessels. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 124, No. 7, pp. 79–100, July, 1997     

HDL-binding lipoproteins on human fetal hepatocytes

Two types of binding sites for high-density lipoproteins (K_d=1 μg/ml and 20 μg/ml) were identified on human fetal hepatocytes and designated as P₁ and P₂. Ligand blotting has shown that P₁ site is protein with Mr 100 kD and P₂ site involves two proteins with Mr 105 and 110 kD. P₂ proteins were not detected when incubation with ligands was shortened from 24 h to 30 min. Molecular weight and activity of P₁ did not change considerably after reduction of disulfide bonds. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 126, No. 10, pp. 459–463, October, 1998