Is Na,K-ATPase the target of oxidative stress?

The susceptibility of Na,K-ATPase from bovine brain to various compounds containing active oxygen radicals is assessed. Sodium nitroprusside slightly inhibits Na,K-ATPase, while light-induced NO^o radicals (controlled by the rate of ascorbate oxidation) have no effect on the enzyme. When added in concentrations equally effective in the ascorbate oxidation assay, hydrogen peroxide and sodium hypochlorite inhibit Na,K-ATPase by 70 and 25–30%, respectively. The Fe-dinitrosyl-cysteine complex is the most potent (K_0.5=20 μM) inhibitor of Na,K-ATPase. It is demonstrated that different free oxygen radicals accumulated in the ischemic brain cause different kinds of damage to Na,K-ATPase. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 121, N ^o 3, pp. 275–278, March, 1996 Presented by I. P. Ashmarin, Member of the Russian Academy of Medical Sciences     

The content of tocopherol and lipid peroxidation products in the tissues of rats with genetically determined hyperproduction of free oxygen radicals

It is shown that at the age of 2–3 months S rats with genetically determined hyperproduction of free radicals have the same content of tocopherol in the heart, epididymal fat, adrenals, liver, and liver mitochondria as Wistar rats but a lower content of plasma tocopherol. At 10–12 months, the tocopherol content in all studied tissues and organs, except the liver, is higher than in young S rats and age-matched Wistar rats. This is regarded as a compensatory response facilitating the stabilization of LPO under conditions of increased free radical formation. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 121, N ^o 3, pp. 282–284, March, 1996     

Proton NMR relaxation of the nonaqueous component of human blood serum

Proton magnetic resonance relaxation was experimentally studied in native blood serum in groups of healthy subjects and patients with malignant tumors. Although the longitudinal relaxation timeT ₁ of the aqueous component in these groups was found to differ reliably, the longitudinal relaxation time of nonexchanging or slowly exchanging protons in these samples within the attained range of accuracy was virtually the same. Moreover, it was revealed that the amplitude of the “nonaqueous component” of blood serum correlates with the protein concentration in the samples. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 120, N ^o 10, pp. 445–448, October, 1995     

Stimulation of proliferative activity of human natural killers (CD16+CD56+ cells) by recombinant interleukin-3in vitro

The proliferative activity of human natural killers (CD16⁺CD56⁺ cells) in the presence of 100 and 1000 IU/ml human recombinant interleukin-3 is investigatedin vitro. It is shown that recombinant interleukin-3 reliably enhances natural killer proliferation, causing a 9–15.2-fold increase of³H-thymidine uptake by CD16⁺CD56⁺ cells both in complete culture medium and in conditioned medium. The effect of the factor is 3.9–6.4 and 3.6–8.9-fold more potent than that of recombinant interleukin-2 and granulocyte-macrophage colony-stimulating factor, respectively, in the same doses. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 119, N ^o 4, pp. 409–412, April, 1995 Presented by S. V. Prozorovskii, Member of the Russian Academy of Medical Sciences     

Effects of muscarine agonists and antagonists on vasopressin-stimulated water transport in the amphibian bladder

The effects of M₁ and M₂ cholinoceptors on stimulated water transport in the urinary bladder of the common frogRana temporaria L. are described. In the presence of pirenzepine, a selective M₁ cholinoceptor antagonist, carbachol stimulated water transport. Activation of M₂ cholinoceptors by oxotremorine in concentrations of 0.5–5.0 μM inhibited water transport, whereas their activation by this compound in higher concentrations (10–100 μM) stimulated it. The use of the phospholipase C inhibitor neomycin (0.5 mM) and the calmodulin inhibitor W-7 (1 mM) indicated that activation of M₂ cholinoceptors switches on phospholipid-Ca²⁺-calmodulin-dependent mechanisms. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 120, N ^o 9, pp. 252–254, September, 1995 (Presented by P. V. Sergeev, Member of the Russian Academy of Medical Sciences)     

Antioxidant properties of thiamine

Thiamine (10⁻⁴–10⁻⁶ M) inhibits lipid peroxidation in rat liver microsome and free radical oxidation of oleic acidin vitro. Thiamine interacts with free radicals and hydroperoxides and is oxidized to thiochrome and thiamine disulfide. The antioxidant effect of thiamine is probably related to sucessive transfer of 2H⁺ from the NH₂ group of the pyrimidine ring and H⁺ from the thiazole ring (after its opening) to reactive substrates. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 130, No. 9, pp. 303–305, September, 2000     

Role of mast cells in reparative processes in inflammation

Using the model of acute infectious peritonitis in rats, it is shown that inflammation induced in the absence of mast cells is characterized by marked inhibition of reparative processes. The most significant accumulation of functionally active fibroblasts and the development of granulations and young connective tissue in the mesentery occur 5–10 days after flogogen injection in the natural development of inflammation and after 10–20 days in the absence of mast cells. The data suggest that under natural conditions mast cells directly or indirectly stimulate reparative processes. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 119, N ^o 3, pp. 262–265, March, 1995 Presented by E. D. Gol'dberg, Member of the Russian Academy of Medical Sciences     

Comparison of the blood level of endogenous paramagnetics in health and pathology using proton magnetic relaxation

An experimental study is made of the longitudinal proton relaxation timeT ₁ in human serum in health and pathology as a function of the protein concentration using partially lyophilized samples. A comparison of the results with those obtained with modeled aqueous protein solutions and extrapolation of the dependences to the zero concentration demonstrate that the concentration of paramagnetic admixtures is the same in groups of healthy subjects and patients with malignant neoplasms who have reliably differentT ₁ values in native samples. There is no difference in the longitudinal proton relaxation time of the nonaqueous component of the serum between these groups. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 120, N ^o 11, pp. 557–560, November, 1995     

Antioxidant properties of thiamine

Thiamine (10⁻⁴–10⁻⁶ M) inhibits lipid peroxidation in rat liver microsome and free radical oxidation of oleic acidin vitro. Thiamine interacts with free radicals and hydroperoxides and is oxidized to thiochrome and thiamine disulfide. The antioxidant effect of thiamine is probably related to sucessive transfer of 2H⁺ from the NH₂ group of the pyrimidine ring and H⁺ from the thiazole ring (after its opening) to reactive substrates. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 130, No. 9, pp. 303–305, September, 2000     

Carnosine and related compounds inhibit chemiluminescence of human plasma lipoproteinsin vitro

The antioxidant activity of carnosine and related compounds (5 and 10 mM) is assessed from the chemiluminescence curve using a model of Fe-initiated lipid peroxidation of human serum apoB-lipoproteins. These agents lower to different degrees the amplitudes of “fast” and “slow” bursts, the reaction rate, and the chemiluminescence light sum; the latency is prolonged, which may occur upon reduction of lipid hydroperoxides and/or inactivation of free radicals. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 119, N ^o 2, pp. 152–154, February, 1995 Presented by I. P. Ashmarin. Member of the Russian Academy of Medical Sciences     

Synthesis and properties of the immunotoxin CD5-ricin

Synthesis and properties of an immunotoxin produced by conjugating ricin with a novel monoclonal antibody (IgG3 of the ICO-104 class) are described. Cytolytic activity of the synthesized immunotoxin, determined by two independent methods and expressed in LD₅₀, is 0.3–0.6×10⁻⁷ M. Its specificity for target cells containing the CD5 antigen is shown. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 119, N ^o 1, pp. 76–79, January, 1995 (Presented by Yu. A. Romanov, Member of the Russian Academy of Medical Sciences)     

Impact of plasmin and its complexes with α2-macroglobulin or α2-antiplasmin on the proliferative activity of human lymphocyteson the proliferative activity of human lymphocytes

It is shown that plasmin in doses of 0.1, 1, or 10 μg/ml did not influence significantly phytohemagglutinin-induced proliferation of mononuclear lymphocytes in a 3-day culture with these cells. Their proliferative response to pokeweed mitogen was stimulated by plasmin in the dose of 10 μg/ml only. Biogenic complexes of plasmin with α₂-macroglobulin or α₂-antiplasmin induced a moderate reduction of spontaneous proliferation after 3 days of culture, and so did plasmin after 5 days; α₂-macroglobulin induced a dose-dependent comitogenic effect with phytohemagglutinin and pokeweed mitogen, while α₂-antiplasmin induced a dose-independent comitogenic effect with pokeweed mitogen. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 118, N ^o 9, pp. 304–305, September, 1994 Presented by V. A. Trufakin, Member of the Russian Academy of Medical Sciences     

Effect of a peptide extract of fetal brain tissue on the intracellular pH of mouse peritoneal phagocytes

The intracellular pH (pH_i) of mouse peritoneal neutrophils, initially 0.2 U, drops after a 15-min incubation of these cells with a peptide extract of fetal brain tissue. Treatment with the preparation leads to appreciable changes in the distribution of neutrophils by the examined parameter. For macrophages, the acidifying effect of the agent and its effect on the pattern of cell distribution in terms of pH values are far less expressed. The effects of the agent in dilutions 1∶10² and 1∶10⁴ on the mean pH_i are virtually the same. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 120, N ^o 12, pp. 626–630, December, 1995 Presented by V. I. Kulakov, Member of the Russian Academy of Medical Sciences     

On the mechanism of insulinotropic action of hepoxylins: Evidence of a direct,glucose-independent effect of hepoxylins B3 on insulin secretion

The effects of lipoxygenase metabolites of arachidonic acid, hepoxylin B₃ epimers, on insulin secretion by a culture of isolated islet cells were studied. The effect was assessed at hepoxylin B₃ concentrations of 0.2 to 5.0 μM and different glucose concentrations in the culture medium. Both hepoxylin B₃ epimers were shown to boost the stimulating effect of glucose on insulin secretion. This effect manifests itself at glucose concentrations of 5.5 and 11 mM and disappears at an above normal glucose content in the medium (20 mM). The capacity of hepoxylin B₃ to stimulate the secretion of insulin by a culture of islet cells in a glucose-free medium has also been demonstrated. This direct, not glucose-mediated, insulinotropic effect may serve as proof that the hepoxylins belong to the category of intracellular messengers. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 120, N ^o 10, pp. 404–406, October, 1995 Presented by I. G. Akmaev, Member of the Russian Academy of Medical Sciences     

Effect of human defensins on the cytoplasmic Ca2+ content in platelets

The effect of the total fraction of human defensins (HNP-1, HNP-2, and HNP-3) on the cytoplasmic Ca²⁺ content ([Ca²⁺]_i) in the platelets of healthy donors was studied. At concentrations of 0.1–40 μg/ml and an incubation time of 10 min defensins have no effect on [Ca²⁺]_i in platelets labeled with Fura-2AM. However, at higher concentrations (100 μg/ml) they increased platelet [Ca²⁺]_i. In addition, defensins (40 μg/ml) inhibited the Ca²⁺ increase in platelets induced by thrombin, adenosine diphosphate, and the lipopolysaccharide ofS. typhimurium endotoxin. The most pronounced inhibitory effect was observed in a suspension of thrombin-stimulated platelets. It is shown that the effect of human defensins on the functional activity of platelets is due to the alterations in the intracellular Ca²⁺. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 118, N ^o 12, pp. 600–603, December, 1994     

The development of free radical processes in experimental bronchospasm. Effect of the bronchodilator preparation troventol

The development of bronchospasm is shown to be accompanied by lipid peroxidation (LPO) activation; 3-fold and 8-fold rises of malondialdehyde concentration are found in homogenate of lung from sensitized animals and from animals provoked with egg albumin antigen, respectively. The use of luminol-dependent chemiluminescence (CL) reveals that in sensitized rats the production of oxygen free radicals is increased by alveolar macrophages activated with phorbol myristate acetate. Troventol at 10⁻³ mg/ml inhibits the CL response of phagocytes both in intact and in sensitized rats and lowers the level of Fe²⁺-induced LPO in lung tissue but not in the liver of intact animals. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 117, N ^o 6, pp. 619–621, June, 1994     

Effect of exogenous acetylcholine on neuromuscular transmission in the stimulated rat diaphragm

Nerve stimulation is performed in rat phrenicodiaphragmal preparations with armine-inhibited acetylcholinesterase. Acetylcholine (1×10⁻⁷ M) is added to the saline for 15 min, and as it is washed off (during 1–2 h), the amplitude of isometric contractions and of the total action potential increases in the continuously stimulated muscle. Contractions in response to direct muscle stimulation remain unchanged. The membrane resting potential of muscle fibers exposed to acetylcholine shifts by 2–3 mV toward hyperpolarization and remains at this level for 2 h after the removal of acetylcholine from the saline. Presented by S. N. Golikov, Member of the Russian Academy of Medical Sciences Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 118, N ^o 11, pp. 457–459, November, 1994     

Derivation of a new B-cell line from mouse spleen and its characterization

Prolonged culturing of splenocytes of (CBA×C57B1/6)F₁ hybrid mice in RPMI-1640 medium with 15% fetal calf serum resulted in the derivation of a new B-cell line. After a monolayer of stromal fibroblast-like cells was formed, lymphoid cell growth was observed in 4–5 weeks of splenic cell culturing. All the cells of the splenic line belonged to the B series and expressed IgM on their surface; they did not form lymphoid colonies after injection to lethally irradiated mice, and even after 8-month culturing and several passages they could not be differentiated. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 119, N ^o 2, pp. 183–186, February, 1995 Presented by I. P. Ashmarin, Member of the Russian Academy of Medical Sciences     

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     

Hereditary cardiomyopathy in W/SSM rats: Biochemical mechanisms of development

One mechanism shown to be responsible for the occurrence of hypertrophic cardiomyopathy in rats of the W/SSM strain, in which this disease is genetically determined, is impairment of cellular membrane integrity resulting from increased hexose transport to cells, generation of hydroxyl radicals, and intensified lipid peroxidation. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 120, N ^o 8, pp. 151–154, August, 1995