Effect of chlorophos (dipterex,trichlorphon) on high-threshold potassium and calcium channels of the neuronal membrane

The effect of chlorophos (dipterex, trichlorphon) on high-threshold potassium and calcium currents is studied on isolated snail neurons using the patch-clamp technique. Chlorophos (10–1000 μmol/liter) is found to reversibly lower the peak amplitude of a high-threshold potassium current by 30% on average and exerts two independent effects on a high-threshold calcium current: reversible lowering of the peak amplitude by 35% on average and, in 30% of cases, reversible inhibition of its activation, inactivation, and deactivation. this effect is abolished by adding diltiazem (a calcium channel antagonist) in a concentration of 100 μmol/liter to the medium. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 121, N ^o 1, pp. 59–62, January, 1996 Presented by Yu. A. Romanov, Member of the Russian Academy of Medical Sciences     

Impact of 13(S)-HPODE,a lipoxygenase product of linoleic acid,on calcium transport and Na,K-ATPase activity in the myocardial sarcolemma

In thisin vitro study using a purified sarcolemmic fraction of guinea pig myocardium, the 13(S)-hydroperoxide of linoleic acid (13-HPODE) increased in a dose-dependent manner the permeability of myocardial sarcolemma to Ca ions in concentrations above 10 μmol/liter, stimulated Na/Ca exchange there in concentrations from 0.1 to 10 μmol/liter, and exerted a digitalis-like action on sarcolemmic Na,K-ATPase in concentrations between 0.1 and 100 μmol/liter (IC₅₀=20 μmol/liter). The results indicate that the linoleic acid hydroperoxide may be an effective modulator of sarcolemmic Ca²⁺ transport and of membrane-bound enzymes. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 120, N ^o 9, pp. 255–257, September, 1995 Presented by D. F. Chebotarev, Member of the Russian Academy of Medical Sciences     

Study of the hemostatic properties of gaseous ozone

The hemostatic properties of ozone were studied on models of parenchymatous (from a wound in the liver) and stem (from the stump of the tail) bleedings in rats. An air-ozone mixture at a flow rate of 1 liter/min and a concentration of 2 mg/ml was found to exert a pronounced hemostatic effect. Our findings indicate that the arrest of bleeding under the influence of ozone is due to the formation of a fibrin membrane on the surface of the flowing blood, this leading to rapid and effective hemostasis. Preliminary drying of the wound still further speeds the onset of hemostasis. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 120 N ^o 7 pp. 62–65, July, 1995 Presented by D. S. Sarkisov, Member of the Russian Academy of Medical Sciences     

Composition of glycoproteins of the supraepithelial mucous layer of the intestinal tract for administration of pentagastrin and carbacholine

The composition of structural glycoproteins from the supraepithelial mucous layer of the stomach and intestine was determined by the concentration of the protein part and monosaccharides of the oligosaccharide part in dogs. It is shown that after administration of pentagastrin at 10 μg/kg and carbacholine at 6 μg/kg the release of structural glycoproteins increases in the stomach (the degree of glycosylation as well as the partial composition of monosaccharides does not markedly change). After stimulation of gastric secretion, the release of structural glycoproteins in the intestine increases insignificantly, whereas the glycosylation of glycoproteins from the supraepithelial mucous layer of the stomach is intensified. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 118, N ^o 9, 237–240, September, 1994     

Plasma content of 2-thiobarbituric acid-reactive substances in mice protected with zinc-metallothionein against acute alcohol intoxication

The malonic dialdehyde content in murine plasma decreases considerably after 1–24 h of acute alcohol intoxication (3 g/kg intraperitoneally). Zinc-metallothionein from rat liver administered in a dose of 2 mg/kg prior to alcohol normalizes the malonic dialdehyde level, whereas a mixture modeling zinc-metallothionein (albumin, cysteine, and zinc) does not change it. A 2- to 2.5-fold increase in the malonic dialdehyde content is observed in all cases after 3 days. It is assumed that the effect of zinc-metallothionein is associated with its ability, similarly to other thiol compounds, to stimulate the metabolism of ethanol and acetaldehyde and to reduce the toxicity of the latter by forming mixed compounds. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 119, N ^o 1, pp. 46–49, January, 1995 Presented by I. V. Domoradskii, 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     

Effects of long-term alcoholic intoxication,ethanol withdrawal,and insulin on glucose utilization,hexokinase activity,and ATP level in rat erythrocytes

Erythrocytes from rats that have been receiving ethanol for 30 days show a reduced capacity to utilize glucose and a reduced hexokinase activity. Following ethanol withdrawal, glucose utilization by erythrocytes and their hexokinase activity do not change significantly, while the ATP level in these cells drops. Insulin administered to the rats after ethanol withdrawal normalizes glucose utilization and ATP and raises hexokinase activity to levels exceeding its control values. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 117, N ^o 1, pp. 29–32, January, 1994 Presented by P. V. Sergeev, Member of the Russian Academy of Medical Sciences     

Antenatal effects of ethanol and limontar on lipid peroxidation and the antioxidant defense system in the brain and liver of rat progeny

In contrast to short-term exposure, prolonged exposure to ethanol in the anternatal period is found to inhibit lipid peroxidation in the brain and liver of rats. Activation of the system of antioxidant defense in the brain and liver is observed after both short-and long-term exposure to ethanol. After short-term ethanol exposure, limontar normalizes lipid peroxidation. Translated fromByulleten' Eksperimental'noii Biologii i Meditsiny, Vol. 117, N ^o 1, pp. 41–44, January, 1994 Presented by M. Ya. Studenikin, Member of the Russian Academy of Medical Sciences     

Responses of the arterial and venous vessels of the skeletal muscle to norepinephrine following damage to their endothelium

The functional activity of vascular endothelium in a muscle preparation from the feline gastrocnemius is impaired with ethanol, which results in an increase of an adrenergic responsiveness of the arterial compartment of the vascular bed. The exchange function of the microvessels changes little. Veins exhibit nonuniform changes in their responsiveness after exposure of their endotheliocytes to ethanol. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 118, N ^o 9, pp. 315–318, September, 1994     

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     

Physicochemical properties of membranes and functional status of liver mitochondria in rats with an inherited capacity for increased radical formation

Liver mitochondria of inbred W/SSM rats with inherited increased radical formation reveal the following anomalies: inhibition of oxidative phosphorylation, a lowered transmembrane potential, and alterations in protein-lipid interaction. The membrane viscosity and osmotic stability of mitochondria are unaffected. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 119, N ^o 6, pp. 628–631, June, 1995     

Localization of sites where abnormal miniature end-plate currents arise at the myoneural junction

Frog cutaneous-sternal muscle preparations were used to examine mechanisms by which extracellularly recorded abnormal miniature postsynaptic signals are generated. The frequency of these signals was found to increase after denervation as well as after the addition of 4-aminoquinolinic acid (0.25 mmol/liter) and emetine (10 mmol/liter) to the solution perfusing the preparation. Graphic delineation, using a 3-electrode technique, of the sites where signals were arising in the nerve terminal showed that neurotransmitter (acetylcholine) quanta responsible for the generation of postsynaptic signals emerged in limited areas of the myoneural junction between terminal portions of the active zones instead of being released from the latter. It is concluded that the source of such quanta is most likely to be the Schwann cell and that the mechanism via which the neurotransmitter is released from this cell is distinct from the mechanism of its release from the nerve terminal. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 120, N ^o 9, pp. 235–238, September, 1995 Presented by A. D. Ado, 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     

Prophylactic and corrective action of the polyethylene oxide polyox WSR-301 in rats with experimental lipoidosis

Two once-weekly intravenous injections of the polyethylene oxide Polyox WSR-301 (yielding a blood concentration of the order of 5×10⁻⁶ g/ml) led to a 38% decrease in the area occupied by sudanophilic lesions in the aortic arch of rats fed an atherogenic diet for two weeks. Perfusion under constant pressure of the formalin-fixed vascular system in the posterior part of the body with physiological saline and then with polyethylene oxide (10⁻⁵ g/ml) was without effect in normal rats and in those with mild lipoidosis, but reduced hydrodynamic vascular resistance by 9–14.5% in rats with pronounced lipoidosis. Intravenous injection of polyethylene oxide into anesthetized rats with pronounced lipoidosis in doses that were subthreshold for normal rats (blood concentrations of the polymer were of the order of 10⁻⁷ g/ml) caused a 20% decrease in the total peripheral resistance to blood flow, with a 17–20% rise of the blood flow rate in the carotid artery. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 119, N ^o 6, pp. 587–589, June, 1995 Presented by I. P. Ashmarin, Member of the Russian Academy of Medical Sciences     

Effects of low-dose ethanol on rat progeny upon inhalation exposure during gestation

Effects of ethanol in low concentrations on the course of pregnancy in rats and the development and metabolic characteristics of their progeny are studied: the morphology and function of pathological shifts are assessed and the level of endogenous ethanol in the blood and acetylcholinesterase activity in erythrocyte membranes measured. Inhalation exposure to ethanol is found to retard the development of the progeny. The consumption of ethanol by the progeny in the experimental group was 1.5 times higher than in the control. The results indicate that even trace amounts of ethanol in the atmosphere are toxic for the organism. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 121, N ^o 3, pp. 265–267, March, 1996 Presented by I. P. Ashmarin, Member of the Russian Academy of Medical Sciences     

Formation of colonies of clonogenic stromal precursors in bone marrow and splenic cell cultures in the presence of streptococcal antigens in the culture medium

The presence of streptococcal M protein and A polysaccharide in culture medium is shown to have an inhibitory effect on the growth of clonogenic stromal precursors in cultures of healthy murine bone marrow and of healthy guinea pig bone marrow and spleen. The efficacy of colony formation dropped 1.5- to 2-fold in the presence of antigens in a concentration of 25 μg/ml in the medium. The inhibitory effect was absent if antigens were added to adhesive cell cultures. The addition of antigens to cultures originating from animals immunized with streptococcus resulted in inhibition of the efficacy of colony formation in complete cultures and in cultures of adhesive cells. The presence of streptococcal antigens in guinea pig stromal fibroblast cultures of different strains did not affect their growth or colony formation. These data indicate that the effects of streptococcal antigens appear to be aimed at the stromal cells not directly, but rather via another cellular category in the bone marrow and splenic cell cultures, probably lymphocytes. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 118, N ^o 11, pp. 489–492, November, 1994     

Effect of dimethylsulfate on the structure and cytoarchitectonics of rat thymus

Changes of structure and cell ratios of different functional zones in the thymus under conditions of long-term dimethylsulfate administration at 0.1 and 2.0 mg/m³ on the organism are studied morphometrically on histological preparations from Wistar rats. Cyclic reactions of the thymus to the toxic substance are found to be due to compensatory processes. It is shown that the nature of the reaction does not depend on the concentration of toxic substance but that the extent of changes is a function of the dimethylsulfate concentration. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 119, N ^o 1, pp. 96–100, January, 1995     

Polyunsaturated phosphatidylcholine micelle-induced decrease of atherogenicity of the serumin vitro

It is shown that polyunsaturated phosphatidylcholine administered in micelles stabilized by a plant-derived glycoside prevents the accumulation of cholesterol by cells incubated in atherogenic serum and, moreover, in certain cases causes a 1.4–1.5-fold drop of intracellular cholesterol as compared to control cells. The optimum antiatherogenic effect was achieved when using a micelle concentration of 100–200 μg/ml and an incubation time of at least 4 hours. The antiatherogenic effect was analogous to the effect of high density serum lipoproteins. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 119, N ^o 5 pp. 497–501, May, 1995 Presented by Yu. M. Lopukhin, Member of the Russian Academy of Medical Sciences     

Delayed-type hypersensitivity and the pathogenesis of viral hemorrhagic fever (African swine fever)

A potent inhibition of leukocyte migration, as high as 98%, was observed in superacute and acute forms and exacerbation of the chronic form of African swine fever. In an asymptomatic infection the inhibition is no more than 30%. Inhibition of the migration of porcine leukocytes infected in a cell culture was 73 to 90% after infection with four virulent strains and 15 to 36% after infection with two attenuated strains. The data onin vitro andin vivo leukocyte sensitization in African swine fever are indicative of a correlation between the severity of the pathogenetic picture of the disease and the degree of delayed-type hypersensitivity. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 118, N ^o 8, pp. 168–170, August, 1994 Presented by A. A. Vorob'ev, Member of the Russian Academy of Medical Sciences     

Effect of picrotoxin and bicuculline on desensitization of the GABA receptor/Cl− ionophore complex

A study is performed of the effect of the convulsants picrotoxin and bicuculline, blockers of GABA-dependent Cl⁻-conductivity, on the rate of desensitization of muscimol-induced³⁶Cl⁻ entry into synaptoneurosomes isolated from rat cortex. Both picrotoxin and bicuculline, despite the difference in the mechanisms of inhibition of the GABA receptor/Cl⁻ ionophore complex, markedly reduce the rate of desensitization. However, the initial moment of the action of both convulsants is characterized by inhibition of Cl⁻ transport alone, without a drop of the rate of desensitization. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 118, N ^o 8, pp. 160–163, August, 1994