<Emphasis Type="Italic">In vitro</Emphasis> effects of thyroliberin on structural state of plasma membranes in mouse brain and liver

The spin probe method was employed to study in vitro the effect of regulatory peptide thyroliberin on structural state of surface (0.8 nm) and deep (2 nm) lipid layers of the plasma membranes in mouse liver and brain. Thyroliberin in a concentration range of 10⁻³–10⁻¹⁸ M enhanced structural order of surface lipids, the maximum effect was observed at 10⁻⁹–10⁻¹⁰ M. The dose-effect dependencies for microviscosity of deep lipids were nonlinear and had 3 extrema at 10⁻⁴–10⁻⁷ M, 10⁻⁹ M, and 10⁻¹⁴–10⁻¹⁶ M. The greatest changes in lipid microviscosity produced by 10⁻⁹ M thyroliberin are explained by lipid-receptor interaction. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 144, No. 8, pp. 151–154, August, 2007     

Modification of ethylmethane sulfonate-induced mytagenesis with adrenaline

Experiments withCrepis capillaris dry seeds show that pretreatment with adrenaline hydrochloride and adrenaline hydrotartrate significantly reduces the number of aberrations induced by the supermutagen ethylmethane sulfonate. The effective concentration ranges for adrenaline adrenaline hydrotartrate and hydrochloride are 10⁻¹–10⁻⁷ M and 10⁻³–10⁻⁷ M, respectively. Adrenaline hydrochloride is more effective than adrenaline hydrotartrate (79.1vs. 65%, respectively). Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 126, No. 10, pp. 427–429, October, 1998     

Effect of the phenol antioxidant katavidan on autooxidation of microsomes exposed to visible light

A study is performed of the effect of the phenol antioxidant katavidan on autooxidation of microsomes from rat liver exposed to visible light. It is shown that katavidan in a concentration of 10⁻³ M inhibits but in concentrations of 10⁻⁵–10⁻⁷ M stimulates autooxidation of microsomes. No stimulation is observed under conditions of dark incubation. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 118, № 10, pp. 393–394, October, 1994 Presented by I. P. Ashmarin, Member of the Russian Academy of Medical Sciences     

Comparative study of the effect of amiridine on biological membranes

The effects of amiridine and of the comparable drugs tacrine and piracetam on synaptosomes and membranes of sarcoplasmic reticulum were studied by electron paramagnetic resonance; in addition, the effects of these drugs on the activity of Ca²⁺, Mg²⁺-dependent ATPase regulating calcium transport in neurons were investigated. In concentrations of 10⁻⁷ to 10⁻⁵ M the drugs did not affect the structure of synaptosomal membranes of rat brain. Amiridine and tacrine in a concentration of 0.1 mM reduced the rate of calcium ion transport across the sarcoplasmic reticulum membrane by inhibiting the function of Ca²⁺, Mg²⁺-dependent ATPase and induced marked changes of the structural rigidity of the protein part of the membrane. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 120, N№ 11, pp. 503–505, November, 1995 Presented by Yu. A. Romanov, Member of the Russian Academy of Medical Sciences     

Effects of the nootropics piracetam and GVS-111 on voltage-dependent ion channels of neuronal membranes

The effect of two nootropics, piracetam and N-phenylacetyl-L-prolyglycine ethyl ester (GVS-111), is studied by measuring high-threshold K⁺ and Ca²⁺ currents in isolated snail neurons using a two-microelectrode patch-clamp technique. Piracetam and GVS-111 are shown to reduce the amplitude of both the K⁺ and the Ca²⁺ (to a lesser extent) current. The threshold concentrations for GVS-111 and piracetam are 10⁻⁹-10⁻⁸ M and 1–5×10⁻⁴ M, respectively. It is assumed that the antiamnestic effect of the nootropics is partially mediated by a blockade of ion channels of the neuronal membrane. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 121, N ^o 2, pp. 151–155, February, 1996 Presented by G. N. Kryzhanovskii, Member of the Russian Academy of Medical Sciences     

In vitro effects of folic acid on γ-glutamyltransferase and glutathione reductase activities in malignant lung and thymus tumors

In vitro effects of folic acid (10⁻⁵, 10⁻⁴, and 10⁻³ M) on activities of γ-glutamyltransferase and glutathione reductase, the enzymes involved in glutathione metabolism, were studied in tissue samples obtained after surgical treatment of the lungs and thymus. Folic acid did not change γ-glutamyltransferase activity in lung cancer tissue, but in thymoma tissue this substance in a concentration of 10⁻³ M inhibited it by 16%. Folic acid had no effects on glutathione reductase activity in benign tumors and normal lung and thymus tissues, but increased this activity in thymoma and lung cancer tissues. Activation of glutathione reductase was probably related to binding of folic acid in the allosteric center of the enzyme, which probably induced conformational changes in the catalytic center, acceleration of electron transport from NADPH₂ to oxidized glutathione via flavin adenine nucleotide, and intense production of reduced glutathione. Translated fromByulleten', Eksperimental'noi Biologii i Meditsiny, Vol. 130, No. 10, pp. 422–425, October, 2000     

Interaction of bis-β-chlorethylamine estrogen derivatives with human ovarian adenocarcinoma cells

Antiproliferative effect of bis-β-chlorethylamine estrogen derivatives on human ovarian adenocarcinoma CaOV cells depends on the dose of the drug. In concentrations of 10⁻⁵ and 5×10⁻⁶ M they inhibit, while in a dose of 5×10⁻⁷ M stimulate cell proliferation. It is assumed that CaOV cells express estradiol receptors. The interaction of these cytostatics with estrogen-binding sites on CaOV cells is demonstrated. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 127, No. 3, pp. 302–304, March, 1999     

Xymedon restores T-cell immune response inhibited by γ-irradiationin vivo: Interrelations with Ca2+-ATPase and DNA-relaxing activities

High radioprotective activity of xymedon was shown in mice. Radioprotective effects of this preparation were accompanied by restoration of the delayed-type hypersensitivity response and Ca²⁺-ATPase activity in splenocytes which were inhibited by γ-irradiation (3 Gy). At concentrations of 10⁻³ and 10⁻⁶ M xymedon stimulated the activity of DNA topoisomerase-I of splenocyte nuclei. Here we discuss a mechanism of radioprotective effects of pyrimidine derivatives associated with the inhibition of apoptosis of lymphoid cells and the stimulation of proliferation and differentiation of lymphoid precursor cells. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 127, No. 1, pp. 66–70, January, 1999     

Effects of calcium antagonists on serotonin-dependent aggregation and serotonin transport in platelets of patients with migraine

Flunarizine and cinnarizine (IC₅₀ 6.8×10⁻⁶ and 2.8×10⁻⁵ M, respectively) inhibited³H-serotonin uptake by platelets. In higher doses, they blocked serotonin-induced platelet aggregation and stimulated³H-serotonin release from these cells. Imipramine did not affect serotonin-releasing effects of preparations. In all patients cinnarizine was more potent in inhibiting serotonin uptake, and in half of the patients cinnarizine displayed higher activity as an inductor of serotonin release. Translated fromByulleten's Eksperimental'noi Biologii i Meditsiny, Vol. 130, No. 7, pp. 24–27, July, 2000     

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     

Effect of muscimol on the picrotoxinand bicuculline-induced delay in the desensitization of the GABA receptor/Cl− channel complex

Effects of picrotoxin and bicuculline on the muscimol-dependent³⁶Cl⁻ entry into synaptoneurosomes of the rat cerebral cortex are examined as well as desensitization of³⁶Cl⁻ entry at muscimol concentrations of 5 and 50 μM. At the 5 μM concentration (which is close to the muscimol IC₅₀), picrotoxin and bicuculline inhibited Cl⁻ entry into synaptoneurosomes and decreased the desensitization. At the 50 μM concentration, muscimol completely abolishes the bicuculline effects both on Cl⁻ entry and desensitization. Inhibition of Cl⁻ entry by picrotoxin is also abolished by 50 μM muscimol, whereas the picrotoxin-induced decrease in the desensitization rate is not. It is shown that both bicuculline effects result from inhibition of the GABA receptor, but the action of picrotoxin on the desensitization of Cl⁻ entry into synaptoneurosomes is not closely related to the functional activity of the GABA receptor/Cl⁻ channel complex. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 122, No. 8, pp. 144–147, August, 1996     

Effects of calcium antagonists on serotonin-dependent aggregation and serotonin transport in platelets of patients with migraine

Flunarizine and cinnarizine (IC₅₀ 6.8×10⁻⁶ and 2.8×10⁻⁵ M, respectively) inhibited³H-serotonin uptake by platelets. In higher doses, they blocked serotonin-induced platelet aggregation and stimulated³H-serotonin release from these cells. Imipramine did not affect serotonin-releasing effects of preparations. In all patients cinnarizine was more potent in inhibiting serotonin uptake, and in half of the patients cinnarizine displayed higher activity as an inductor of serotonin release. Translated fromByulleten's Eksperimental'noi Biologii i Meditsiny, Vol. 130, No. 7, pp. 24–27, July, 2000     

Effects of sex hormones and antihormones on the activity of redox system enzymes of human erythrocyte glutathione

Effects of estradiol and testosterone and of the antiandrogens cyproterone acetate, niftolide, and antiestrogen tamoxifen on the activities of human erythrocyte glutathione peroxidase and glutathione reductase were studiedin vitro. In contrast to hormone preperations, antihormones in high concentrations (10⁻⁴−5×10⁻⁴ M) modified the enzyme activities. Cyproterone acetate and tamoxifen increased the activity of glutathione reductase, while tamoxifen stimulated glutathione reductase and inhibited glutathione peroxidase. Niftolide inhibited both enzymes. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 124, No. 8, pp. 185–187, August, 1997     

Effects of homeopathic doses of antibodies to S100 antigen on electric characteristics of neuronal membranes

Various dilutions of antibodies to brain-specific protein S100, including those prepared by multiple consecutive dilutions up to 10⁻¹² and 10⁻⁴⁰⁰ of total weight, produced similar effects on the membranes ofHelix pomatia giant neurons, which varied only quantitatively. They induced membrane depolarization, reduced the amplitude or completely blocked the action potential, accelerated the maximal rise of the action potential, reduced maximal conductance, and facilitated the steady-state inactivation of ionic channels. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 127, No. 4, pp. 466–467, April, 1999     

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     

Assessment of nucleosomal DNA fragmentation in lung adenocarcinoma cells incubated with human platelets

No nucleosomal fragmentation of DNA from lung adenocarcinoma cells was observed after 18 h of their incubation with normal human platelets isolated from human peripheral blood. Platelet activation with 10⁻⁶, 10⁻⁷, and 10⁻⁸ M PAF did not lead to nucleosomal fragmentation of the target cell DNA. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 124, No. 11, pp. 547–549, November, 1997     

Effects of synthetic bis-β-chloroethylamine estrogen derivatives on proliferation of skin sarcoma cells

The effects of four new synthetic bis-β-chloroethylamine-containing estrogens and known cytostatic agents chlorophenacyl and estradiol mustard were compared on monolayer cultures of transformed L-929 fibroblasts (from murine skin sarcoma). The drugs within the concentration range of 10⁻⁵-5×10⁻⁷M inhibited proliferation of cultured cells by 67%. Chlorophenacyl displayed the least antiproliferative activity (15% inhibition at 10⁻⁵M). Steroid nucleus introduced into the molecule enhanced antiproliferative activity of test drug in comparison with chlorophenacyl, probably due to accumulation of the hormone-cytostatic molecules in cells. Estradiol had no effect on proliferative activity of L-929 cells, and no specific estrogen-binding sites were found in cultured transformed fibroblasts. The antiproliferative effect of hormone-cytostatics on this culture is not mediated via specific interactions with estrogen receptors. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 129, No. 6, pp. 695–697, June, 2000     

Pharmacological analysis of the activity of phenazepam and flunitrazepam administered in superlow doses

Benzodiazepine tranquilizers, phenazepam and flunitrazepam, administered to random-bred albino male rats in superlow doses (10⁻⁹–10⁻¹⁵ mol/kg), are shown to exert an anxiolytic effect in the conflict test. In contrast to the case with the usual doses, the above effect is not accompanied by marked myorelaxant or sedative effects. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 121, № 2, pp. 164–166, February, 1996     

Effects of dose and administration mode of endothelin 1 on the mean arterial pressure and heart rate in awake rats

The effects of bolus administration and short-term infusion of endothelin 1 in four doses (2×10⁻¹⁶, 2×10⁻¹⁴, 2×10⁻¹², and 2×10⁻¹⁰ mol/kg) on arterial pressure and heart rate were compared in awake rats. Infusion and bolus administration of the two highest doses increased arterial pressure and provoked bradycardia. Infusion of the two lowest doses increased heart rate without concomitant changes in arterial pressure, while bolus injection of endothelin 1 in the same doses decreased both arterial pressure and the heart rate. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 124, No. 11, pp. 491–494, November, 1997     

Modulation of the oxidative burst in mouse macrophages and human neutrophils by superlow concentrations of GM1 ganglioside

It is shown that ganglioside GM1 in picomolar concentrations stimulates the phorbol-12-myristate-13-acetate (PMA)-induced generation of active forms of oxygen by neutrophils and peritoneal macrophages. GM1 (10⁻¹¹ M) is found to enhance the luminol-dependent chemiluminescence induced by 10⁻⁸ M PMA in mouse macrophages in comparison with the effect of PMA alone. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 117, N ^o 1, pp. 44–46, January, 1994 Presented by A. N. Klimov, Member of the Russian Academy of Medical Sciences