Electromagnetic radiation of the terahertz range at the nitric oxide frequency in correction and prophylaxis of functional activity disorders in thrombocytes of white rats under long-term stress

The influence of electromagnetic waves of terahertz range at the frequencies of molecular spectrum o nitric oxide radiation and absorption on functional activity of thrombocytes in white rats under long-term stress has been studied. It has been shown that courses of THzF treatment applied during the stress can prevent and restore disorders in thrombocytes aggregative function. The stress factor does not induce characteristic of stress-reaction disturbances of microcirculation in animals treated with the preventive course of THzF.     

Effect of ionizing radiation on the functional state of the vascular-thrombocytic component of the hemostasis system

The influence of ionizing radiation (gamma-rays 60Co) on aggregation activity of the vascular wall and functional (aggregation) platelet activity was studied in the course of the development of acute radiation sickness. The decrease in the aggregation properties of the vascular wall and high functional activity of platelets were inversely proportional, correlating with the periods of acute radiation sickness development and depending on the radiation dose. It is suggested that the changes detected may play a role in the pathogenesis of the development of the postirradiation thrombohemorrhagic syndrome.     

A Study on Molecular Mechanisms of Terahertz Radiation Interaction with Biopolymers Based on the Example of Bovine Serum Albumin

Biophysics - The effect of terahertz radiation on the functional activity of bovine serum albumin was studied by electron paramagnetic resonance spectroscopy using spin trapping and spin probing...     

Correlation between calpain-mediated cytoskeletal degradation and expression of platelet procoagulant activity. A role for the platelet membrane-skeleton in the regulation of membrane lipid asymmetry?

The relationship between platelet calpain-activity and platelet procoagulant-activity was investigated by comparison of the time course of their generation after platelet stimulation by calcium ionophore A23187, or by the combined action of collagen and thrombin, or during exposure of platelets to the local anesthetics dibucaine or tetracaine. In addition, the Ca2+ dose-response curves of both activities in intact platelets, obtained by stimulation with A23187 in the presence of Ca2+/HEDTA-buffers, were compared. Platelet procoagulant activity was determined by assaying for prothrombinase activity in the presence of saturating concentrations of factors Xa, Va, and prothrombin. Platelet calpain activity was monitored by the degradation of its major substrates (filamin, talin, myosin) and the formation of their fragments as judged from protein patterns after gel electrophoresis. Platelet stimulation by A23187 resulted in a fast increase in prothrombinase activity, reaching its maximum level after about 20 seconds. Filamin and talin were completely hydrolysed within 15 s, and myosin was partly degraded between 15 and 30 s after platelet activation. When platelets were activated by collagen plus thrombin, prothrombinase activity was generated with a sigmoid time course, the steepest increase being observed between 1 and 2 min after platelet activation. Proteolysis of filamin and talin occurred between 0.5 and 1.5 min after platelet activation, while degradation of myosin became visible after 2 to 2.5 min. Dibucaine and tetracaine were both found to be potent stimulators of prothrombinase activity, with half-maximal activities obtained at 0.7 and 2.8 mM, respectively. Using suboptimal concentrations of both local anesthetics, it was found that the generation of prothrombinase activity closely paralleled that of calpain activity over a time course of 1 hour. Ca2+ titration of intact platelets using A23187 and Ca2+/HEDTA buffers, revealed half-maximal response at about 15 microM free Ca2+ for both calpain and prothrombinase activity. These findings strongly suggest a causal relationship between generation of a procoagulant platelet surface and calpain-mediated degradation of filamin, talin, and myosin. Since an increased procoagulant activity reflects an increased exposure of phosphatidylserine at the platelet outer surface, the present findings suggest that platelet cytoskeletal proteins are involved in the regulation of membrane lipid asymmetry.     

The effect of electromagnetic waves of very high frequency of molecular spectra of radiation and absorption of nitric oxide on the functional activity of platelets

A study was made of the effect of electromagnetic EMI MMD-fluctuation on the frequencies of molecular spectra of radiation, and nitric oxide absorption under in vitro conditions on the functional activity of platelets in patients with unstable angina pectoris, with the help of a specially created generator. At amplitude-modulated and continuous modes of EMI MMD-irradiation of platelet-rich plasma for 5, 15 and 30 min the platelet functional activity decreases, which was shown up in reduction of their activation and fall of aggregative ability. The degree, to which platelet functional activity was inhibited, depended on the mode of irradiation and on duration of EMI MMD effect. The most obvious changes in platelet activation and in their readiness to aggregative response were observed at a continuous mode of irradiation within a 15 min interval.     

Correlation between calpain-mediated cytoskeletal degradation and expression of platelet procoagulant activity. A role for the platelet membrane-skeleton in the regulation of membrane lipid asymmetry?

The relationship between platelet calpain-activity and platelet procoagulant-activity was investigated by comparison of the time course of their generation after platelet stimulation by calcium ionophore A23187, or by the combined action of collagen and thrombin, or during exposure of platelets to the local anesthetics dibucaine or tetracaine. In addition, the Ca²⁺ dose-response curves of both activities in intact platelets, obtained by stimulation with A23187 in the presence of Ca²⁺/HEDTA-buffers, were compared. Platelet procoagulant activity was determined by assaying for prothrombinase activity in the presence of saturating concentrations of factors Xa, Va, and prothrombin. Platelet calpain activity was monitored by the degradation of its major substrates (filamin, talin, myosin) and the formation of their fragments as judged from protein patterns after gel electrophoresis. Platelet stimulation by A23187 resulted in a fast increase in prothrombinase activity, reaching its maximum level after about 20 seconds. Filamin and talin were completely hydrolysed within 15 s, and myosin was partly degraded between 15 and 30 s after platelet activation. When platelets were activated by collagen plus thrombin, prothrombinase activity was generated with a sigmoid time course, the steepest increase being observed between 1 and 2 min after platelet activation. Proteolysis of filamin and talin occurred between 0.5 and 1.5 min after platelet activation, while degradation of myosin became visible after 2 to 2.5 min. Dibucaine and tetracaine were both found to be potent stimulators of prothrombinase activity, with half-maximal activities obtained at 0.7 and 2.8 mM, respectively. Using suboptimal concentrations of both local anesthetics, it was found that the generation of prothrombinase activity closely paralleled that of calpain activity over a time course of 1 hour. Ca²⁺ titration of intact platelets using A23187 and Ca²⁺/HEDTA buffers, revealed half-maximal response at about 15 μM free Ca²⁺ for both calpain and prothrombinase activity. These findings strongly suggest a causal relationship between generation of a procoagulant platelet surface and calpain-mediated degradation of filamin, talin, and myosin. Since an increased procoagulant activity reflects an increased exposure of phosphatidylserine at the platelet outer surface, the present findings suggest that platelet cytoskeletal proteins are involved in the regulation of membrane lipid asymmetry.     

Coagulation hemostasis and fibrinolytic potential of blood in conditions of chronic stress and terahertz therapy

The effects of electromagnetic rays of maximum high frequencies of radiation molecular spectrum and absorption of nitrogen oxide 150, 176-150, 664 GHz on blood coagulation properties of white laboratory rats subjected to chronic immobilization stress have been studied. It is shown that preventive course of electromagnetic irradiation with terahertz range at the frequencies of molecular spectrum of radiation and absorption of nitrogen oxide 150, 176-150, 664 GHz warns about development of stress disturbances of coagulation component of the hemostasis system and fibrinolysis in animals.     

Effect of thymic humoral factor in vitro on human bone marrow and blood cells from B-, T- and null-cell acute lymphatic leukemia.

The nature of null-cell acute lymphatic leukemia (ALL) was investigated with the aid of a thymic humoral factor (THF), bone marrow cells, and a local xenogeneic graft-versus-host reaction (GVHR). Lymphocytes obtained from the blood and bone marrow of six children with T-cell ALL, five with null-cell ALL, one with perinatal B-cell ALL, one with acute myelocytic leukemia, and one with erythroleukemia were tested for membrane surface markers (E, EAC, and SM Ig); functional activity of T cells was tested by a local GVHR. All of the specimens obtained at the initial presentation showed a lack of functional activity of the lymphocytes. Incubation of null cell and acute myelocytic leukemia (AML) bone marrow with THF led to the acquisition of the characteristics of functional, immunocompetent T cells. No such effect was seen when the bone marrow of T-cell ALL and peripheral blood lymphocytes of B-cell perinatal ALL were incubated with THF. This study demonstrates that the null cell in ALL bone marrow can be differentiated into a T cell whereas the stem cell in AML bone marrow constitutes a pluripotential undifferentiated cell which also can mature into a T cell.     

Cleaved forms of C-reactive protein are associated with platelet inhibition

C-reactive protein (CRP) is the prototypic acute phase reactant and serves clinically as a marker of inflammation and tissue destruction. When native CRP pentamer was incubated with Streptomyces griseus protease, a newly formed and transient ability to inhibit platelet aggregation stimulated by adenosine diphosphate or collagen was often elicited early during the course of enzymatic digestion. Sodium dodecyl sulfate polyacrylamide gel electrophoresis analyses of the digests revealed that platelet inhibitory activity correlated with altered electrophoretic mobility and reductions in subunit and pentameric m.w. Minimally degraded forms of CRP were also isolated "de novo" from inflammatory fluids and, like their enzyme degraded counterparts, inhibited platelet activation. Dissociation of degraded CRP with SDS followed by the removal of SDS resulted in the separation fragments which inhibited platelet function. We propose that in a degradative environment, such as at sites of inflammation/tissue damage or through the action of serum proteases, CRP may transitorily down-regulate the platelet.     

Synthesis and anti-tumor activity of carbohydrate analogues of the tetrahydrofuran containing acetogenins

The tetrahydrofuran (THF) containing annonaceous acetogenins (AAs) are attractive candidates for drug development because of their potent cytotoxicity against a wide range of tumors and their relatively simple and robust structures. Replacement of the THF segment with a sugar residue may deliver analogues with improved tumor selectivity and pharmacokinetics and are therefore attractive for drug development. As a first test to the feasibility of such structures, a set of such monosaccharide analogues was synthesized and assayed against four human tumor cell lines, cervical (HeLa), breast (MDA-MB231), T-cell leukemia (Jurkat) and prostate (PC-3). Certain analogues showed low micromolar activity that was comparable to a structurally similar, naturally occurring mono-THF acetogenin. A preliminary examination of the structure–activity profile of these carbohydrate analogues suggests that they have a similar mechanism of action as their THF congeners.     

Isolation and functional characterization of the von Willebrand factor-binding domain located between residues His1-Arg293 of the alpha-chain of glycoprotein Ib

In the present report we describe the isolation of a functional domain of platelet membrane glycoprotein (GP) Ib which retains von Willebrand factor (vWF)-binding activity. Glycocalicin, a proteolytic fragment of the alpha-chain of GP Ib generated by an endogenous calcium-activated protease, was submitted to digestion with trypsin. The two resulting fragments, one of 45 kDa extending between residues His1 and Arg293 and representing the amino terminus of the alpha-chain, the other of 84 kDa corresponding to the previously described macroglycopeptide, were purified to homogeneity. Glycocalicin, as well as the 45- and 84-kDa fragments, inhibited the ristocetin-dependent binding of native vWF to platelet GP Ib. The concentration inhibiting 50% of binding (IC50) was between 1 and 5 microM with all these molecules. In contrast, the binding of asialo-vWF to platelet GP Ib, measured directly in the absence of ristocetin, was blocked by glycocalicin and the 45-kDa fragment with a similar IC50, but not by the 84-kDa fragment. Both glycocalicin and the 45-kDa fragment bound to purified surface-bound vWF in a ristocetin-dependent manner and with similar affinities. Monoclonal antibodies against vWF or GP Ib inhibited this interaction in a way consistent with their inhibition of vWF binding to platelet GP Ib. These studies demonstrate that the amino-terminal extracytoplasmic region of the alpha-chain, extending between residues 1 and 293, contains a functional domain that interacts with vWF in the absence of any other structure of the GP Ib complex or any other platelet membrane component. Whereas the ristocetin-dependent binding of vWF may involve also other domains in the macroglycopeptide region, the direct vWF-GP Ib interaction appears to be mediated only by a domain in the amino-terminal region of GP Ib alpha.     

Comparative evaluation of the efficiency of the effect of very high frequency electromagnetic waves on platelet functional activity

A comparative analysis was made of the effect of two kinds of EMI MMD-radiation: EMI MMD-waves, generated by a vehicle "Jav-1 M" (42.2 and 53.5 HHz), and EMI MMD-waves exerting influence with frequencies of molecular spectrum of radiation and nitric oxide absorption (150.176-150.644 HHz), obtained with a specially created generator, with respect to their influence on the functional ability of platelets of unstable angina pectoris patients. It was shown that in vitro EMI MMD-fluctuations with frequencies of molecular spectrum of radiation and nitric oxide absorption exert a stronger inhibiting influence on the functional activity of platelets of unstable angina pectoris patients. Features of the action of various kinds of EMI MMD-effect on the activative-high-speed characteristics of platelet aggregation are shown.     

Effect of NMDA receptor activity on histone H3 methylation and its asymmetry in the hippocampal pyramidal neurons of rats with different excitability thresholds under normal and stress conditions

Process of methylation of histone H3 for lysine 4 (H3K4) was studied in hippocampal pyramidal neurons of rats—intact and submitted to emotional-pain stress with active and inactivated channels of NMDA-receptors with taking into account the interhemisphere lateralization and in connection with the genetically determined level of excitability of the animals’ nervous system. There were revealed interstrain differences in the basal level of the H3K4 methylation whose direction depends on structural-functional peculiarities of hippocampal fields and lateralization. Under action of stress the direction of the observed changes in the degree of the H3K4 methylation depended on the functional states of channels of NMDA-receptors. On the background of active receptors the proportion of immunopositive cells predominantly increased. In the CA1 field this change was not connected with excitability and lateralization, whereas in the CA3 field it had a complex character and depended on these two factors. At inactivation of channels of NMDA-receptors the portion of immunopositive nuclei as a result of the stress action, on the contrary, predominantly decreased; interstrain specificity of these changes was connected with lateralization, while its direction in different hippocampal fields was different. Action of the short-time emotional-pain stress did not lead to a change of shape of interhemisphere at active state of receptors, whereas at inactivation of receptors it changes depending on the structural-functional organization of hippocampus and on excitability of the nervous system.     

Emotional stress and problems of radiation medicine

The influence of emotional stress on behaviour and industrial activity of man as well as on the development of posttraumatic stressful frustration and other disorders is considered in connection with real or possible action of ionizing radiation, and on the course of radiation injuries. It is shown that a problem of emotional stress and radiation safety are closely connected. The study is important for solving problems facing emergency medicine.     

Mechanism of antioxidant protection of an organism from oxidative stress

The analysis of the literature and authors' data concerning the mechanism of antioxidant protection of the organism under conditions of "oxygen stress" is submitted. Possible mechanisms of initiation of free radical reactions with participation of oxygen and the role of hydroxyl radicals, being one of the basic factors, determining toxic action of oxygen, are considered. The methods of estimation of antiradical activity of biologically active compounds are characterized.     

Inhibition of platelet factor XIIIa-catalyzed reactions by calmodulin

Calmodulin was found to exhibit an inhibitory effect on platelet factor XIIIa-catalyzed incorporation of pseudodonor amines into dimethylcasein, platelet actin and myosin. The inhibitory action of calmodulin on the calcium-dependent enzyme reactions was analogous to the effects of EGTA and parvalbumin on these reactions. The extent of inhibition of factor XIIIa activity was a function of calmodulin concentration when factor XIII and Ca2+ concentrations were held constant. These results indicate that calmodulin inhibits platelet factor XIIIa-catalyzed reactions by sequestering calcium.     

The effect of changes in the lipid composition of membranes on the functional activity of platelets

The phospholipid and fatty acid composition as well as the effect of platelet lipid composition modifications on the functional parameters of platelets were studied in blood sera from healthy donors and from patients with ischemic heart disease (IHD). It was found that the content of cholesterol and phospholipid hydrolysis products in IHD patients was increased. Reconstitution of the lipid composition of donor platelets by lysophosphatidylcholines, phosphatidic acid, fatty acids and cholesterol led to the increase of the platelet functional activity. It is suggested that the increased adsorption of Ca2+ on platelet surface is due to alterations in the platelet lipid composition in IHD and after modifications.     

EEG changes and platelet aggregation in experimental cerebral focal ischemia in rabbits

Nine white New Zealand rabbits were submitted to internal carotid embolization with microspheres which caused a histologically verified focal cerebral ischemia. Six animals were sham-operated. EEG, QEEG, ECG, blood pressure, rectal temperature and platelet aggregation were monitored in basal conditions and one hour after ischemia. Embolized animals showed an increase in power density spectrum (PDS) and delta activity (0.15-3.70 Hz) and the appearance of platelet aggregation. The QEEG changes were correlated to the degree of platelet aggregation after ischemia.     

Lipoxin B, an enhancing factor of spontaneous platelet aggregation in whole blood

The arachidonic acid metabolites, lipoxin B (5,14,15-trihydroxy-6,8,10,12-eicosatetraenoate) and 5,15-dihydroxy-eicosatetraenoate were shown to possess a marked effect on platelet aggregation and procoagulant activity. Lipoxin B increases and 5,15-dihydroxy-eicosatetraenoate decreases spontaneous platelet aggregation and procoagulant activity when added at various concentrations. The drugs tested were found to have no direct action on blood coagulation.