Inhibition of platelet aggregation under the action of sodium hypochlorite. Effect of blood plasma components

The proteins fibrinogen and serum albumin and the amino acid alanine modified by sodium hypochlorite are shown to inhibit thrombin-induced aggregation of isolated platelets. The hypochlorite sodium-treated proteins and amino acids acquire the capacity to counter platelet aggregation as a result of the formation of chloramine derivatives. The aggregating capacity of hypochlorite sodium-inactivated platelets can be restored by native plasma and fibrinogen. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 119, N ^o 5, pp. 488–490, May, 1995 Presented by Yu. M. Lopukhin, Member of the Russian Academy of Medical Sciences     

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     

Mechanisms of platelet function alterations induced by low-intensity laser radiation

Effects of laser radiation (wavelength 630 nm, power 1 mW) on platelet aggregation in human bloodin vitro andin vivo and on platelet sensitivity to thromboxane A as well as on cyclooxygenase and thromboxane synthetase activities were studied. Changes in platelet functional activity were shown to be related to platelet transformation into inactive discoid form, suppression of their sensitivity to endogenous activators, and decreased activity of the arachidonic acid cascade enzymes. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 126, No. 7, pp. 45–48, July, 1998     

Mechanism of hypocoagulative effect of low-intensity laser radiation

Aggregation of platelets and their role in the hypocoagulation syndrome was studied afterin vitro irradiation of blood with a laser. Thromboelastography was performed in platelet-rich and platelet-free plasma. Low-intensity laser radiation affected the coagulation system via platelets. It decreased platelet aggregation induced by ADP, collagen, epinephrine, ristocetin, platelet activating factor, and fibrinogen. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 126, No. 7, pp. 36–38, July, 1998     

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 Parmidine (pyridinolcarbamate) on platelet aggregation,blood coagulation,and fibrinolysis

The effect of Parmidine (pyridinolcarbamate) on platelet aggregation, blood coagulation, and fibrinolysis was studied in rabbits. After direct addition of Parmidine to platelet-enriched plasma aggregation of the platelets produced by serotonin (5-HT) and adrenalin was reduced. After oral administration of Parmidine to animals, aggregation induced by ADP, 5-HT, and adrenalin was inhibited, blood coagulation was reduced, and fibrinolysis was accelerated.Laboratory of Pharmacology, S. Ordzhonikidze All-Union Pharmaceutical Chemical Research Institute. Department of Pharmacology, Therapeutic Faculty, Moscow Medical Stomatological Institute. Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 81, No. 3, pp. 322–324, March, 1976.     

Effect of recombinant forms of urokinase plasminogen activator on platelet aggregation and intracellular calcium accumulation

Urokinase caused plasmin-dependent inhibition of platelet aggregation in platelet-rich plasma, while its proteolytically inactive form had no such effect. Both forms potentiated the increase in platelet calcium concentration induced by aggregation inductors and facilitated aggregation of washed platelets. In contrast to full-length urokinase molecule, its aminoterminal fragment inhibited platelet aggregation and the corresponding elevation of intracellular calcium. These data suggest that urokinase exerts a plasmin-independent effect on platelet activity. This effect depends on urokinase structure. Translated formByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 128, No. 9, pp. 339–343, September 1999     

Immunoenzyme assay of glycocalicin, platelet glycoprotein Ib fragment. Evaluation of platelet turnover in circulation and differential diagnosis of thrombocytopenia

We propose a method for measurement of plasma glycocalicin, a fragment of platelet membrane glycoprotein Ib. The concentration of glycocalicin is elevated in thrombocythemia and reduced in thrombocytopenia caused by insufficient platelet production, but not in immune thrombocytopenia due to enhanced platelet degradation. Thus, plasma content of glycocalicin is an indicator of platelet turnover. The proposed assay can be used for differential diagnostics of thrombocytopenia. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 128, No. 10, pp. 476–479, October, 1999     

Mechanism of the hypercoagulant effect of hyperoxia

Inhalation of 100% O₂ at normal atmospheric pressure for 30 min is accompanied by an increase in the clotting power of the blood and a sharp decrease in the number of platelets, with changes in their structure, in man and rabbits. The trigger mechanism of this hypercoagulant effect is probably viscous metamorphosis of the platelets, developing under the influence of activation of Hageman's factor by oxygen.Kirghiz Medical Institute, Frunze. Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 84, No. 10, pp. 421–423, October, 1977     

Laser correlation spectroscopy in an investigation of the subfractional composition of plasma from patients with gastric bleeding,craniocerebral injury,and intoxications

Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 116, N ^o 8, pp. 220–222 August, 1993     

Mechanism of the lipid-mobilizing action of ethimizole

The effect of ethimizole on the mobilization of fatty acids and the role of hormones of the pituitary-adrenal system in the lipolytic effect of ethimizole were studied in experiments on rats. The lipid-mobilizing action of ethimizole was well marked in intact, hypophysectomized, and adrenalectomized rats. The effect of the drug disappeared in animals after simultaneous extirpation of the pituitary and adrenals but was restored when these animals were given hydrocotisone. It is concluded that ethimizole has a direct action on the mobilization of fatty acids and that corticosteroids play a permissive role in the lipid-mobilizing effect of ethimizole.Department of Pharmacology, Institute of Experimental Medicine, Academy of Medical Sciences of the USSR, Leningrad. (Presented by Academician of the Academy of Medical Sciences of the USSR S. V. Anichkov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 84, No. 9, pp. 321–323, September, 1977.     

Mechanism of action of neurohypophyseal hormones on sodium excretion and diuresis

Administration of pituitrin, vasopressin, and oxytocin to rats during spontaneous micturition increases diuresis and sodium excretion by reducing tubular reabsorption. In adrenalectomized rats these preparations have no diuretic effect and increased sodium excretion is observed only after administration of vasopressin. After hypophysectomy the diuretic effect of the preparations disappears but they still increase sodium excretion. It is postulated that the diuretic effect of the neurohypophyseal hormones is connected with activation of the pituitary-adrenal system, whereas some additional mechanism is involved in their effect on sodium excretion.Presented by Academician of the Academy of Medical Sciences of the USSR V. V. Zakusov.Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 80, No. 8, pp. 8–11, August, 1975.     

Mechanism of action of neurohypophyseal hormones on sodium excretion and diuresis

Administration of pituitrin, vasopressin, and oxytocin to rats during spontaneous micturition increases diuresis and sodium excretion by reducing tubular reabsorption. In adrenalectomized rats these preparations have no diuretic effect and increased sodium excretion is observed only after administration of vasopressin. After hypophysectomy the diuretic effect of the preparations disappears but they still increase sodium excretion. It is postulated that the diuretic effect of the neurohypophyseal hormones is connected with activation of the pituitary-adrenal system, whereas some additional mechanism is involved in their effect on sodium excretion.Presented by Academician of the Academy of Medical Sciences of the USSR V. V. Zakusov.Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 80, No. 8, pp. 8–11, August, 1975.     

Inhibition of platelet aggregation by monoclonal antibodies against glycoprotein IIb–IIIa complex

Monoclonal antibodies CRC64 are obtained against Ca²⁺-dependent glycoprotein IIb–IIIa complex of the platelet membrane which possess the ability to inhibit completely fibrinogen-dependent platelet aggregation. CRC64 is directed against the epitope formed by the glycoprotein IIb–IIIa complex and does not interact with proteins isolated after platelets are treated with ethylenediamine tetraacetate. Complete, reproducible blockade of platelet aggregation caused by 5 μM adenosine diphosphate is noted in an MCA concentration of 3 μg/ml, while in the case of a stronger inductor, namely 1 U/ml thrombin, platelet aggregation is inhibited in a concentration of 5 μg/ml. F(ab′)₂ fragments are also able to inhibit platelet aggregation completely and are usually effective in concentrations lower than native monoclonal antibodies. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 118, N ^o 10, pp. 402–405, October, 1994 Presented by V. N. Smirnov, Member of the Russian Academy of Medical Sciences     

Mechanism of action of the new cardiotonic suphan on calcium exchange in cardiomyocytes

Effects of suphan, a new cardiotonic agent containing succinyl tryptophan, on the entry of Ca²⁺ into rat cardiomyocytes, its intracellular compartmentalization, and its exit from these cells were evaluatedin vitro. It was found that the recorded sulfan-induced rise of intracellular calcium was due to Ca²⁺ entering the cell via L-type calcium channels, and that a reversible reduction of its concentration in the sarcoplasm occurred through its accumulation in the sarcoplasmic reticulum and was blocked by the specific Ca²⁺-ATPase inhibitor thapsigargin (10 μM). Suphan did not alter the activity of Na⁺/Ca²⁺ exchange in a concentration range of 5–150 μg/ml. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 122, No. 7, pp. 57–59, July, 1996     

Mechanism of action of nonachlazine on nervous control over the coronary circulation

The new antiaginal drug nonachlazine, in experiments on anesthetized cats and dogs, inhibited the response of reflex decrease of the blood flow into the coronary arteries. In freely behaving cats nonachlazine also inhibited reflex changes in the blood flow in the system of the common carotid artery and reduced pressor vasomotor reflexes. Nonachlazine selectively inhibited vasoconstrictor impulses from A-afferent fibers of spinal nerves, i.e., it acts on the vasomotor component of the primary nociceptive response. This mechanism may perhaps lie at the basis of the relief of the pain syndrome by nonachlazine in ischemic heart disease.Laboratory of Pharmacology of the Cardiovascular System, Institute of Pharmacology, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR V. V. Zakusov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 81, No. 3, pp. 319–322, March, 1976.     

Mechanism of the influence of sympathetic nerves on kidney function

In dogs receiving large doses of reserpine hyponatriemia, hypokaliemia, oliguria, a reduction in the renal blood flow and in the sodium and potassium excretion, together with abolition of the inhibitory effect of the splanchnic nerve on the function of the glomerular and tubular portions of the nephron are observed as the result of functional insufficiency of the sympathetic innervation of the kidneys through the development of catecholamine deficiency.Department of Normal Physiology and Faculty of Surgery, S. M. Kurashov Kazan' Medical Institute. (Presented by Academician of the Academy of Medical Sciences of the USSR A. A. Vishnevskii.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 82, No. 8, pp. 910–911, August, 1976.Deceased     

Effects of sex hormones on plasma lipid peroxidationin vitro

The effects of sex steroid hormones on the level of plasma lipid peroxidation are studiedin vitro. Estradiol shows pronounced antioxidative activity; progesterone and testosterone slightly suppress lipid peroxidation only when used in high concentrations. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 124, No. 7, pp. 73–76, July, 1997     

Early stages in the mechanism of action of glucocorticoids on human platelets. Effect of hydrocortisone on intracellular cAMP and Ca2+ content

Changes in basal and stimulated levels of cAMP and calcium induced by hydrocortisone in a wide range of concentration (0.1–25 μM) are studies in a suspension of washed human platelets. The effects of hydrocortisone on the activity of preparations modulating various stages of the adenylate cyclase system (forskolin, adenosine, adrenaline, and 3-isobutyl-1-methylxanthine) are compared. Platelets are stimulated with collagen, platelet activating factor, and thapsigargin. Hydrocortisone in different concentrations acts as both activator and inhibitor of calcium metabolism in platelets. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 123, No. 6, pp. 663–665, June, 1997