[The anti-ischemic and antioxidant activity of the pharmacological agonist of galanin receptor GalR2 and carnosine in in vitro and in vivo model systems]. / Protivoishemicheskaia i antioksidantnaia aktivnost' farmakologicheskogo agonista retseptora galanina GalR2 i karnozina v model'nykh sistemakh in vitro i in vivo.

Antioxidant and anti-ischemic properties of the pharmacological agonist of galanin receptor GalR2 WTLNSAGYLLGPßAH (Gal) and its C-terminal fragment, dipeptide carnosine (ßAH), were studied in the model of regional ischemia and reperfusion of the rat heart in vivo in the dose range of 0.5-5.0 mg/kg and Cu²âº-induced free radical oxidation of low density lipoproteins (LDL) of human plasma in vitro for peptide concentrations of 0.01 mM and 0.1 mM. Gal was obtained by automatic solid phase synthesis using the Fmoc methodology; its structure was characterized by 1H-NMR spectroscopy and MALDI-TOF mass spectrometry. Intravenous administration of the optimal dose of Gal (1 mg/kg) to rats after ischemia was more effective than carnosine in reducing of the myocardial infarct size and the activity of creatine kinase-MB and lactate dehydrogenase in blood plasma at the end of reperfusion. It also improved the metabolic state of the reperfused myocardium and reduced the formation of peroxidation products during reperfusion. Gal reduced more effectively the formation of adducts of hydroxyl radicals in the interstitium of the area at risk (AAR) of the rat heart than carnosine. Carnosine at a dose of 1 mg/kg more effectively increased the activity of catalase and glutathione peroxidase in the AAR by the end of reperfusion compared to Gal. In a model of Cu²âº-initiated oxidation of human plasma LDL 0.1 mM carnosine demonstrated a significantly more pronounced reduction in the formation of lipid radicals compared to Gal. The results show that Gal can be considered as a promising agent that reduces myocardial injury during reperfusion and oxidative stress.

EFFECT OF SMOKING STEAM COCKTAILS ON THE HARD TISSUES OF THE ORAL CAVITY.

The aim of the research was to study the impact of smoking steam cocktails on dental status. The study of dental status was carried out by means of a questionnaire, a detailed survey and a clinical examination of patients. The questionnaire was used to determine the level of evaluation of motivation to quit smoking. During the survey of patients, the subjective state of the oral cavity was determined, namely, the presence of dryness of the oral cavity, unpleasant smell, burning sensation, pain in the tongue, impaired taste sensations, and whether there was a metallic taste. Then an external examination was carried out, an examination of the vestibule of the oral cavity, an examination of the dentition itself. The intensity of dental caries was determined. According to the results of the survey, it is clear that the motivation to quit smoking is low. Data from the study in patients who use and do not use smoking mixtures showed that the intensity of caries sharply worsens depending on the length of smoking. The obtained data indicate an increase in inflammatory and destructive changes in the hard tissues of the teeth.

Gaseous Nitric Oxide and Dinitrosyl Iron Complexes with Thiol-Containing Ligands as Potential Medicines that Can Relieve COVID-19.

It is shown that the inhalation of gaseous nitric oxide (gNO) or sprayed aqueous solutions of binuclear dinitrosyl iron complexes with glutathione or N-acetyl-L-cysteine by animals or humans provokes no perceptible hypotensive effects. Potentially, these procedures may be useful in COVID-19 treatment. The NO level in complexes with hemoglobin in blood decreases as the gNO concentration in the gas flow produced by the Plazon system increases from 100 to 2100 ppm, so that at 2000 ppm more than one-half of the gas can be incorporated into dinitrosyl complexes formed in tissues of the lungs and respiratory tract. Thus, the effect of gNO inhalation may be similar to that observed after administration of solutions of dinitrosyl iron complexes, namely, to the presence of dinitrosyl iron complexes with thiol-containing ligands in lung and airway tissues. With regard to the hypothesis posited earlier that these complexes can suppress coronavirus replication as donors of nitrosonium cations (Biophysics 65, 818, 2020), it is not inconceivable that administration of gNO or chemically synthesized dinitrosyl iron complexes with thiol-containing ligands may help treat COVID-19. In tests on the authors of this paper as volunteers, the tolerance concentration of gNO inhaled within 15 min was approximately 2000 ppm. In tests on rats that inhaled sprayed aqueous solutions of dinitrosyl iron complexes, their tolerance dose was approximately 0.4 mmol/kg body weight.

[Possible mechanism of antioxidant action of dinitrosyl iron complexes]. / Vozmozhnyi mekhanizm antioksidantnogo deistviia dinitrozil'nykh kompleksov zheleza.

The antioxidant effect of dinitrosyl iron complexes (DNICs) was studied in various model systems. DNICs with glutathione ligands effectively inhibited Cu2+-induced peroxidation of low density lipoproteins (LDL). The antioxidant effect of DNICs with phosphate ligands and free reduced glutathione (GSH) was less pronounced. In addition, DNICs with glutathione suppressed the formation of reactive oxygen species during co-oxidation of lecithin liposomes and glucose. Free radical oxidation in this system was induced with a lipophilic azo initiator and evaluated by luminol-dependent chemiluminescence. NO sharply stimulated chemiluminescence during co-oxidation of glucose and liposomes, thus suggesting the formation of potent oxidants under these conditions. Glutathione DNICs scavenge the superoxide radical anion generated in the xanthine-xanthine oxidase system. Superoxide production was assessed by lucigenin-dependent chemiluminescence and electron paramagnetic resonance (EPR) spectroscopy. Chemiluminescence revealed the dose-dependent character of antiradical effect of glutathione DNICs; moreover, these complexes turned out to be more efficient than GSH. EPR spectra of the adducts of the DEPMPO spin trap with free radicals suggest that the interaction of glutathione DNICs and superoxide does not result in the formation of the thiyl radical of glutathione. Here we propose a mechanism of the antioxidant action of glutathione DNICs, suggesting that unstable intermediate complexes are formed upon their interaction with superoxide or lipid radicals. Further, as a result of intramolecular rearrangement, these intermediates decompose without the free radical as the by-products.

Study of Translocation of Stabilized NO Forms through Rat Skin using Electron Paramagnetic Resonance Method.

We studied the effect of dinitrosyl-iron complexes with N-acetyl-L-cysteine as a thiol-containing ligand (DNIC-Acc) after transdermal administration to rats. Electron paramagnetic resonance spectroscopy with a lipophilic NO spin trap (a complex of iron and diethyldithiocarbamate ions) showed that DNIC-Acc administration significantly increased the total level of NO in the lung and liver tissues of the animal, which was accompanied by a slight decrease in the mean BP (<10%).

Hypotensive Effect and Accumulation of Dinitrosyl Iron Complexes in Blood and Tissues after Intravenous and Subcutaneous Injection.

Subcutaneous injection of Oxacom with glutathione-bound dinitrosyl iron complex as the active principle produced a slower drop of mean BP and longer accumulation of protein-bound dinitrosyl iron complexes in whole blood and tissues than intravenous injection of this drug, while durations of hypotensive effect in both cases were practically identical. In contrast to intravenous injection of the drug, its subcutaneous administration was not characterized by a high concentration of protein-bound dinitrosyl iron complexes in the blood at the onset of experiment; in addition, accumulation of these NO forms in the lungs was more pronounced after subcutaneous injection than after intravenous one.

[Protective action figurations for superoxide dismutase - chondroitin sulfate - catalase bienzyme conjugate after its medicative administration in endotoxin shock]. / Pokazateli zashchitnogo deistviia bifermentnogo kon"iugata superoksiddismutaza-khondroitinsul'fat-katalaza posle ego lechebnogo vvedeniia pri éndotoksicheskom shoke.

Previously it found that the bienzymatic conjugate superoxide dismutase-chondroitin sulfate, catalase (SOD-CHS-CAT) increased the survival rate of rats with endotoxic shock caused by the administration of lipopolysaccharide (LPS). This effect was observed both in preventive (before LPS) and therapeutic conjugate administration (after the administration of LPS). This study shows that the development of endotoxic shock is accompanied by increased levels of NO in the liver, lungs, kidneys, heart; administration of the SOD-CHS-CAT conjugate insignificantly influenced this parameter. At the same time, the changes in blood urea and creatinine suggest the protective effect of the conjugate on renal function, while diverse changes in biochemical parameters studied complicate the formation of the agreed conclusions on the state of other organs.

[Anti-Tumour Activity of Dinitrosyl Iron Complex with Glutathione and S-Nitrosoglutathione Preparations: Comparative Studies].

The anti-tumor activity of the binuclear form of dinitrosyl iron complexes with glutathione against Lewis lung carcinoma, found earlier upon intraperitoneal administration of the complexes, was also observed when this preparation was injected subcutaneously. A 100 µM/kg subcutaneous dose of the complex being used daily (as calculated per one iron atom in binuclear dinitrosyl iron complexes) for 10 or 15 days, inhibited the tumor growth by 43%. The effect was observed during the first two weeks after tumor transplantation. After that, the tumors began to grow at the rate equal to or even higher than that one for control animals. The mean survival time for treated mice exceeded the control values by 30%. Binuclear dinitrosyl iron complexes administered intraperitoneally was also effective against Ca-755 adenocarcinoma. However, in this case the mean survival time for treated animals increased only by 7%. The anti-tumor activity of S-nitrosoglutathione against Lewis lung carcinoma growth inhibition by 70% and Ca-755 adenocarcinoma growth inhibition by 90% was also shown. However, unlike binuclear dinitrosyl iron complexes the anti-tumor effect of S-nitrosoglutathione decreased when a daily dose of the compound increased (from 200 to 400 µM/kg) The initial anti-tumor effect of binuclear dinitrosyl iron complexes and S-nitrosoglutathione is suggested to be due to NO released from both compounds. A subsequent suppression of the effect is determined by the development of anti-nitrosative and anti-oxidant defense systems in tumors.

Apelin-12 and its structural analog enhance antioxidant defense in experimental myocardial ischemia and reperfusion.

This study investigated the effects of peptide apelin-12 (H-Arg-Pro-Arg-Leu-Ser-His-Lys-Gly-Pro-Met-Pro-Phe-OH, A12) and its novel structural analog (H-(N(α)Me)Arg-Pro-Arg-Leu-Ser-His-Lys-Gly-Pro-Nle-Pro-Phe-OH, AI) on myocardial antioxidant enzyme activities, lipid peroxidation, and reactive oxygen species formation in ex vivo and in vivo models of myocardial ischemia/reperfusion (I/R) injury. Isolated working rat hearts were subjected to global ischemia and reperfusion. Infusion of 140 µM A12 or AI before global ischemia improved cardiac function recovery; increased the activity of Cu,Zn superoxide dismutase (Cu,Zn SOD), catalase (CAT), and glutathione peroxidase (GSH-Px); decreased malondialdehyde (MDA) content in reperfused heart; and reduced the formation of hydroxyl radical adduct of the spin trap 5,5-dimethyl-1-pyrroline-N-oxide in the myocardial effluent during early reperfusion compared with these indices in control. Anesthetized open-chest rats were subjected to the left anterior descending coronary artery occlusion and coronary reperfusion. Peptide A12 or its analog AI was injected intravenously at the onset of reperfusion at a dose of 0.35 µmol/kg. Treatment with A12 or AI significantly limited infarct size and reduced the activity of lactate dehydrogenase and creatine kinase MB isoenzyme in blood plasma at the end of reperfusion compared with control. These effects were accompanied by complete recovery of Cu,Zn SOD, CAT, and GSH-Px activities; and decrease in MDA content in the area at risk by the end of reperfusion. The study concluded that C-terminal fragment of native peptide apelin-12 and its synthesized analog is involved in the upregulation of cardiac antioxidant defense systems and attenuation of lipid peroxidation in myocardial I/R injury.

[Antioxidant properties of apelin-12 and its structural analogue in experimental ischemia and reperfusion].

Effects of apelin-12 H-Arg-Pro-Arg-Leu-Ser-His-Lys-Gly-Pro-Met-Pro-Phe-OH (A12) and its modified analogue H-(NMe)Arg-Pro-Arg-Leu-Ser-His-Lys-Gly-Pro-Nle-Pro-Phe-OH (I) on activity of antioxidant enzymes, formation of malonic dialdehyde (MDA) and generation of reactive oxygen species (ROS) were studied in ex vivo and in vivo models of myocardial ischemia and reperfusion (I/R) injury in Wistar rats. Preischemic infusion of peptide A12 or AI enhanced cardiac function recovery of isolated perfused heart and was accompanied by a marked attenuation of ROS generation detected by electron paramagnetic resonance (EPR) technique in myocardial effluent at early reperfusion compared with control. Intravenous administration (i.v.) of peptides in narcotized rats with regional myocardial ischemia limited infarct size and reduced activity of lactate dehydrogenase and MB-fraction of creatine kinase in plasma at the end of reperfusion. Treatment with peptide A12 prevented reduction or augmented activity of myocardial u/Zn superoxide dismutase, catalase and glutathione peroxidase by the end of reperfusion in both I/R models compared with control. Increased MDA content in the area at risk of rat heart in situ at the end of reperfusion was reduced to the initial value under the effect of i.v. A12 administration. Therefore, cardioprotective action of natural apelin-12 and its structural analog AI involve reduction of short-lived ROS generation and improvement of the antioxidant state of ischemic heart during reperfusion.

[Paramagnetic calcium melanins].

Treatment of catechol, pyrogallol, DOPA, dopamine, norepinephrine, and natural polyhydroxy-1,4-naphthoquinone echinochrome by aqueous solution of potassium superoxide (KO2) in the presence of CaCl2 leads to the formation of water-insoluble dark pigments with stable paramagnetic properties ("calcium melanins"). In control experiments in the same procedure without Ca2+, the pigments were not formed. EPR spectra of the calcium melanins had little difference from each other and from known melanins in shape, line width, and the g factor about 2,004. Addition of EDTA water solution to dried paramagnetic pigments leads to their fast dissolving and disappearing of EPR signal. Formation of similar polymers is also observed during autoxidation of o-diphenols in Ca(2+)-containing alkaline buffer solution, however, this process takes a few days instead of few seconds in the presence of KO2. Thus, calcium (and other divalent cation M2+) can consider as a key structural element in formation of M(2+)-catecholate paramagnetic Polymer. We assume the existence of two types of paramagnetic centers in melanin-like polymer: M(2+)-stabilized o-semiquinone radical or bi-radical complex containing o-semiquinone and superoxide anion radicals, stabilized by M2+.

[Study of dinitrosyl-iron complexes pharmacokinetics and accumulation in depot in rat organs].

Protein-bound dinitrosyl-iron complexes (DNIC) in rat whole blood and organs were studied after intravenous injection of this substance with glutathione ligand (DNIC-GH). The effect of DNIC-GH injection on NO level (including NO physiological forms) in hydrophobic areas of rat tissues was also studied in normal physiological blood circulation condition. It has been shown, that after DNIC-GH injection the concentration of protein-bound DNICs in rat whole blood and organs rapidly reached maximum values, and then gradually decreased, that pointed to decomposition of DNIC molecules, coupled with NO release. At the beginning of the experiment the rates of DNIC decay in rat heart and lung were substantially higher, as compared with those in liver and kidney. By spin trappping it has been demonstrated that DNIC-GH, as a source of NO physiological forms (including S-nitrosothiols), in normal physiological blood circulation influence heart more selectively, as compared with the other organs.

[The study of hypotensive action of dinitrosyl-iron complex with glutathione containing drug oxacom in healthy volunteers].

On the basis of earlier executed studies of hypotensive effect of dinitrosyl iron complexes (DNIC) with glutathione, the drug has been created in industrial conditions named oxacom. Preliminary pharmacological studies of oxacom have not revealed negative qualities. The drug has been now tested in 14 healthy men in whom at single intravenous introduction it caused typical response - a decrease of diastolic as well as systolic arterial pressure on 24-27 mmHg through 3-4 min with subsequent very slow restoration in 8-10 hours. The heart rate after initial rise was quickly normalized. Echocardiography revealed unaltered cardiac output in spite of reduced cardiac filling by 28%. The multilateral analysis of clinical and biochemical data has revealed an absence of essential alterations which could lead to pathological consequences. The drug is recommended for carrying out of the second phase of clinical trial. The comparative study of the efficiency of hypotensive action of oxacom, S-nitrosoglutathione (GS-NO) and sodium nitrite (NO2) in rats has shown that the duration of effect was the greatest at oxacom action.

[Effects of carvedilol and proxodolol on nitric oxide (NO) metabolism in various organs in a congestive heart failure model].

There is certain evidence that high efficacy of beta-adrenoblockers with alpha-adrenoblocking effect (vasodilating beta-blockers) in congestive heart failure (CHF) can be explained by their effect on nitric oxide (NO) metabolism. In this context, the possible effects of carvedilol and proxodolol on the NO level in different organs have been studied on CHF model. The heart failure was modeled in rats by ligation of the coronary artery. Operated animals were divided into experimental groups treated with carvedilol or proxodolol and the untreated (control) group. In addition, a group of sham-operated animals was formed. After 28 days of treatment, the NO level was measured in heart, liver, and kidneys using the EPR method with spin trap. It was found that, in carvedilol-treated group, the NO level in liver is significantly lower than in other groups, which can be explained by the inhibitory action of carvedilol on the NO metabolism in this organ. The NO levels in myocardium and kidney in the control group were higher than in the sham-operated group, which confirms previous findings that the NO levels increases in CHF. Both drugs significantly decreased the NO concentration in myocardium and kidney tissue compared to control animals.

[Dinitrosyl complexes of iron with glutathione in the rat myocardial tissue during regional ischemia and postischemic reperfusion].

The injection of dinitrosyliron iron complexes with glutathione at the onset of 40-min rat regional myocardial ischemia was shown to exert a clear cardioprotective action by decreasing the infarct size and suppressing the cardiac rhythm disturbance. After the introduction of the preparation, its effective accumulation with protein thiol-containing ligands in the myocardial tissue was registered be the EPR method. It was also found that, as a result of postischemic reperfusion, the rate of the decrease in the content of these complexes in the ischemic area increases, which demonstrates the effective scavenging of short-lived reactive oxygen species by molecules of dinitrosyl iron complexes.

[Action of a nitric oxide donor dinitrosyl complex of iron with glutathione on hemodynamics in rats and monkeys].

We studied action of a nitric oxide donor, dinitrosyl complex of iron (DNIC) with glutathione as a ligand on the hemodynamics of normotensive Wistar rats, spontaneously hypertensive rats (SHR), and monkeys. Intravenous DNIC introduction (2-120 mg/kg) rendered fast (1-2 min) hypotensive effect combined with increased heart rate by 10-25%. Second phase of the effect in Wistar rats was characterized by slowed recovery of arterial pressure and heart rate up to initial level. A gradual DNIC breakdown in blood occurred during this period associated with increased NO accumulation in organs with intensive oxidative metabolism (liver, heart, and kidney). Duration of hypotensive effect in all animals depended on dose, this dependence was most expressed in SHR.

[Effects of dinitrosyl iron complex with glutathione and its components on ischemic rat heart during reperfusion].

The effects of the drug, a complex of dinitrosyl iron with glutathione lyophilized on dextrane, and its components: glutathione, nitrosoglutathione, dextrane, as well as nitric oxide released from dinitrosyl iron with glutathione--on the energy metabolism and functional recovery of isolated perfused rat heart subjected to global ischemia and reperfusion have been studied. The infusion of 100 nM dinitrosyl iron with glutathione after ischemia substantially enhanced the recovery of coronary flow, the cardiac contractile and pump functions during reperfusion with simultaneous preservation of myocardial high-energy phosphates, and cell membrane integrity. It was shown by the EPR method that these effects were associated with the transfer of Fe+(NO+)2 groups from dinitrosyl iron with glutathione to thiol-containing proteins of cardiomyocytes and coronary vessels. The combined infusion of 100 nM dinitrosyl iron with glutathione and 25 MM 2-(phenyl)-4,4,5,5-tetramethyl-imidazoline-1-oxyl-3-oxide (PTIO), a nitric oxide scavenger, after ischemia profoundly reduced the metabolic and functional recovery of reperfused hearts. After the postischemic administration of a 100 nM aliquot of hydrolysate of dinitrosyl iron with glutathione (a completely decomposed complex), the recovery of coronary flow, the majority of cardiac function indices, as well as the myocardial metabolic state and cell membrane injury did not differ from those in control or were significantly lower. The results obtained demonstrate that that inclusion of Fe+(NO+)2 groups into myocardial tissue and a spontaneous release of nitric oxide trigger the cardioprotective mechanisms of action of dinitrosyl iron with glutathione on ischemic heart.