[EFFICACY OF DIFFERENT FORMS OF LOCAL HEMOSTATIC MATERIALS BASED ON OXIDIZE CELLULOSE IN THE EXPERIMENT].

The bleeding of intraoperative period is one of the actual problem in surgery. There aren't any universal hemostatic means in spite of large variety of modern hemostatic methods. An experimental research studied the results of hemostatic activity of different forms of materials on the basis of oxidize cellulose (a gauze, a powder) as compared with their foreign analog (a hemostatic gauze "SurgiceI"). Median of hemostasis time consisted of (120 ± 59.9) and (73 ± 46.8) s, in case of application of gauze and powder preparations, respectively. The rate of group using the hemostatic gauze "Surgicel" was (142 ± 77.4) s. The authors made a conclusion on the basis of given research, that the hemostatic material based on oxidize cellulose (the powder form) showed a more expressed hemostatic activity and reliably twice reduced the time of hemostasis as compared with their analog forms of gauze (p < 0.05).

[Hepatoprotective activity of betulonic acid amides containing a piperidine or pyrrolidine nitroxide moiety].

Betulonic acid amides containing a nitroxyl radical moiety possess antiholestatic effects in mice. Introduction ofpiperidine nitroxide moiety into lupan core increases its hepatoprotective activity. Oral administration of piperidine nitroxide derivative in dose 50 mg/kg doesn't stimulate transplanted tumor growth and raises a lifespan of mice.

[Synthetic transformations of higher terpenoids. XXX. Synthesis and cytotoxic activity of betulonic acid amides with a piperidine or pyrrolidine nitroxide moiety].

The reaction of betulonic acid chloride with 4-amino-2,2,6,6-tetramethylpeperidine-1-oxyl, 3-amino-2,2,5,5-tetramethylpyrrolidine-1-oxyl and 3-aminomethyl-2,2,5,5-tetramethylpyrrolidine-1-oxyl gave corresponding triterpenoid amides. It was found that new derivatives exhibit cytotoxic activity against tumor cells CEM-13, U-937, MT-4. CCID50 value for most activity compound--N-[3-oxolup-20(29)-en-30-yl]-(2,2,6,6-tetramethylpiperidine-4-yl)-1-oxyl--was 5.7-33.1 microM.

[In vitro cytotoxicity of nitroxyl radicals with respect to tumor and diploid human cells and estimation of their antiviral activity].

Thirty nine water soluble nitroxyl radicals of various classes, belonging to piperidine, pyrrolidine and imidazolidine series were synthesized. Twenty seven of them were cytotoxic in vitro with respect to the tumor cell culture A431. The CC50 of the most active nitroxyl radicals with respect to cells SW480 and A431 was within 0.16-2.5 mM at the selectivity index of 3.91-7.81 in relation to cytotoxicity of the compounds for the cells of the normal L68 phenotype and tumor cells. The tests on the antiviral activity showed that 16 out of 22 nitroxyl radicals had antiviral activity in Vero cell culture with respect to the West Nile virus and Herpes simplex virus of type II respectively. The EC50 ranged within 0.09-3.45 mM. Some of the nitroxyl radicals had only antiviral activity, but a number of the compounds had both cytotoxic properties and antiviral activity.

Influence of the Electric Charge of Spin Probes on Their Diffusion in Room-Temperature Ionic Liquids.

The rotational and translational diffusion of negatively charged and uncharged spin probes in five imidazolium-based room-temperature ionic liquids (RTILs), 1-ethyl-3-methylimidazolium tetrafluoroborate, emimBF4, 1-butyl-3-methylimidazolium tetrafluoroborate, bmimBF4, 1-octyl-3-methylimidazolium tetrafluoroborate, omimBF4, 1-octyl-3-methylimidazolium hexafluorophosphate, omimPF6, and 1-octyl-3-methylimidazolium chloride, omimCl, has been studied by means of electron paramagnetic resonance spectroscopy. Detailed analyses of the spin-Hamiltonian parameters and spin exchange interactions have been carried out. The temperature dependences of the line broadening induced by the electronic dipole-dipole interaction and the electron spin exchange coupling are determined. The translational mobility of spin probes is semiquantitatively characterized and successfully explained in the framework of a hypothesis based on the assumption of polar and unpolar domains within the RTILs.

EPR and Quantum Chemical Studies of the pH-sensitive Imidazoline and Imidazolidine Nitroxides with Bulky Substituents.

The X- and W-band electron paramagnetic resonance (EPR) spectroscopies were employed to investigate a series of imidazolidine nitroxide radicals with different number of ethyl and methyl substituents at positions 2 and 5 of a heterocycle in liquid and frozen solutions. The influence of the substituents on the line shape and width was studied experimentally and analyzed using quantum chemical calculations. Each pair of the geminal ethyl groups in the positions 2 or 5 of the imidazolidine ring was found to produce an additional hyperfine splitting (hfs) of about 0.2 mT in the EPR spectra of the nitroxides. The effect was attributed to the hfs constant of only one of four methylene hydrogen atoms of two geminal ethyl substituents not fully averaged by ethyl group rotation and ring puckering. In accordance with this assumption, the substitution of hydrogen atoms of CH(2) groups in 2,2,5,5-tetraethyl-substituted imidazolidine nitroxides by deuterium leads to the substantial narrowing of EPR lines which could be useful for many biochemical and biomedical applications, including pH-monitoring. W-band EPR spectra of 2,2,5,5-tetraethyl-substituted imidazolidine nitroxide and its 2,2,5,5-tetraethyl-d(8) deuterium-substituted analog measured at low temperatures demonstrated high sensitivity of their g-factors to pH, which indicates their applicability as spin labels possessing high stability.

Nitroxyl antioxidant TPPA-TEMPO increases the efficacy of antitumor therapy on the model of transplantable mouse tumor.

Nitroxyl antioxidant 4-triphenylphosphonioacetamido-2,2,6,6-tetramethylpiperidine-1-oxyl (TPPA-TEMPO) was synthesized from 4-chloroacetamido-2,2,6,6-tetramethylpiperidine-1-oxyl chloride and triphenylphosphine. Systemic administration of TPPA-TEMPO in the subtoxic dose to mice with lymphosarcoma inhibited tumor growth, but did not prolong animal lifespan. Combined treatment with TPPA-TEMPO and cyclophosphamide increased the efficacy of antitumor therapy: it prolonged animal lifespan and increased the number of recovered mice.

Electron-nuclear double resonance study of molecular librations of nitroxides in molecular glasses: quantum effects at low temperatures, comparison with low-frequency Raman scattering.

Pulsed electron-nuclear double resonance applied to 15N nitroxide spin probes in molecular glasses is shown to be very sensitive to measurement of the A(XX) principal value of the hyperfine interaction tensor. For molecules experiencing fast restricted orientational motions (molecular librations), this provides a precise tool to determine the motion-averaged value. For nitroxides in glycerol and o-terphenyl glasses, the observed temperature dependence below 40 K may be readily interpreted as arising from quantum effects in librations, when the thermal energy of a librating molecule becomes comparable with the elementary quantum of the oscillator. The estimated elementary quanta for nitroxide librations, approximately 60 cm(-1) in glycerol and approximately 90 cm(-1) in o-terphenyl, are found to match the characteristic frequencies of the vibrational spectral densities seen in low-frequency Raman scattering for these glasses. Above approximately 80 K in glycerol and above approximately 120 K in o-terphenyl, the temperature dependences manifest a kink with a slightly smaller slope than at lower temperatures.

Cytotoxicity of spin trapping compounds.

Spin trapping compounds are used frequently to detect free radicals released by cells. Their cytotoxicity has to be considered in order to prevent perturbations of normal cell growth and viability. Eleven spin traps (eight nitrones and three nitroso traps) have been tested for their effects on bovine aortic endothelial cells (toxicity range, 50% survival rate). The lowest cytotoxicity was found for 5,5-dimethylpyrroline-1-oxide and 2,2,4-trimethyl-2H-imidazole-1-oxide whereas nitrosobenzene and 2-methyl-2-nitrosopropane exerted the strongest cytotoxic effects. In addition, three nitronyl nitroxides were tested. Their cytotoxicity was found to be dependent on substitution, and the toxic concentration of a lipophilic derivative was found to be more than two orders lower as compared to a hydrophilic derivative. The results of this study indicate that most spin traps can be used in cell cultures at customary (i.e. millimolar) concentrations; caution is recommended when nitroso spin traps are applied to cells.

NMR spin trapping: detection of free radical reactions with a new fluorinated DMPO analog.

Electron spin resonance (ESR) and nuclear magnetic resonance (NMR) spin trapping were used for detection of free radical reactions utilizing a new fluorinated analog of DMPO, 4-hydroxy-5,5-dimethyl-2-trifluoromethylpyrroline-1-oxide (FDMPO). The parent FDMPO spin trap exhibits a single 19F-NMR resonance at -66.0 ppm. The signal to noise ratio improved 10.4-fold compared to 31P-NMR sensitivity of the phosphorus-containing spin trap, DEPMPO. The spin adducts of FDMPO with .OH, .CH3, and .CH2OH were characterized. Competitive spin trapping of FDMPO with DMPO showed that both have similar rates of addition of .OH and C-centered radicals. The corresponding paramagnetic spin adducts of FDMPO were extremely stable to degradation. In the presence of ascorbate, reaction products from C-centered radicals resulted in the appearance of two additional 19F-NMR signals at -78.6 and -80 ppm for FDMPO/ .CH(3) and at -74.6 and -76.75 ppm for FDMPO/ .CH(2)OH. In each case, these peaks were assigned to the two stereoisomers of their respective, reduced hydroxylamines. The identification of the hydroxylamines for FDMPO/ .CH3 was confirmed by EPR and 19F-NMR spectra of independently synthesized samples. In summary, spin adducts of FDMPO were highly stable for ESR. For NMR spin trapping, FDMPO showed improved signal to noise and similar spin trapping efficiency compared to DEPMPO.

Superoxide-mediated reduction of the nitroxide group can prevent detection of nitric oxide by nitronyl nitroxides.

Nitronyl nitroxides (NN), a class of compounds which react with nitric oxide forming imino nitroxides, were applied in different systems for the detection of nitric oxide. Addition of a NN to planar monolayers of bovine aortic endothelial cells (BAEC) activated by Ca2+ ionophore A23187 immediately resulted in a strong decrease of the ozone-mediated .NO chemiluminescence. Simultaneously, a rapid diminution of the electron spin resonance (ESR) signal intensity of the NN (without detectable formation of the corresponding imino nitroxide) was observed; superoxide dismutase partially inhibited this decrease in the NN concentration. Model experiments using hypoxanthine/xanthine oxidase in aqueous solution and KO2 in dimethylsulfoxide as sources of O2.- revealed that there is a rapid reduction of nitronyl nitroxides by superoxide. The second order rate constant for the reaction of the water soluble NN with O2.- was determined to be 8.8 x 10(5) M-1s-1, which is more than two orders of magnitude higher than the value reported previously for reaction with .NO (Woldman et al., BBRC 202, 195-203, 1994). Reduction of the nitronyl nitroxide was also observed in the presence of glutathione, ascorbic acid or rabbit liver microsomes. Incorporation of both nitronyl and imino nitroxides into liposomes strongly decreased reduction by superoxide and other reductants, however, in the presence of microsomes, there was no protective effect by liposomal encapsulation of NN. The results indicate that in biological systems (in addition to other reducing agents) the presence of superoxide can prevent the detection of nitric oxide using nitronyl nitroxides.

Synthesis and spin trapping applications of 2,2-dimethyl-d6-4-methyl-2H-imidazole-1-oxide-1-15N.

A new spin trap, 2,2-dimethyl-d6-4-methyl-2H-imidazole-1-oxide-1-15N (lTMIO), was synthesized and characterized. Hyperfine splitting (HFS) constants of spin adduct ESR spectra of this compound with oxygen-centered, carbon-centered, thiyl and sulfite-derived radicals were determined and compared with the data of the unsubstituted compound. The increase in ESR spectral intensity and the accompanying decrease of the spectral linewidth result in resolution of the HFS due to interaction with alpha-protons of alkyl radicals trapped by lTMIO. Trapping of the formate radical in deoxygenated aqueous solution revealed a very low spectral linewidth (delta Bpp = 0.028 mT) of the corresponding adduct. A strong dependence of the ESR spectra on pH was observed when the autoxidation product of sulfite, SO3-, was trapped. The pKa was found to be 5.8 +/- 0.3. In comparison to other nitrones, application of this spin trap provides more detailed information on the structure of the species trapped, especially for carbon-centered radicals.

[The EAA-ergic modulation of the brain dopaminergic system as a basis for creating new nootropic agents with stress-protective activity]. / VAK-ergicheskaia moduliatsiia dofaminergicheskoi sistemy mozga kak osnova sozdaniia novykh nootropnykh sredstv so stress-protektivnoi aktivnost'iu.

The paper provides theoretical evidence for and practical confirmation of the possible use of three lipophilic derivatives of N-acetyl-aspartic acid (EAA-AKF-94; AKF-92-10, and PIR-87-6-0). These compounds were shown to display pronounced nootropic activity to correct behavioral, memory, and cognitive disorders in rats exposed to emotional stress. Evidence is provided for the fact that modulation of monoaminergic brain activity mediated by heterosynaptic activation of EAA receptors.

[A method for evaluating the zoosocial behavior of rats in psychopharmacology]. / Metodika otsenki zoosotsial'nogo povedeniia krys v psikhofarmakologii.

The method was proposed for experimental assessment of the drug psychotropic spectrum in rats under pair interaction conditions. The method was based on the recording and analysis of the main behavioral elements with a specially developed point scale. A study was done on spectra of the diazepam, amphetamine, and desipramine activity. The results of pharmacoethological analysis confirm the effectiveness of the proposed method for the assessment of psychotropic spectrum of the well known drugs (diazepam, amphetamine, desipramine), as well as new pharmacological compounds.

[The stress-protector properties of new analogs of mediator amino acids]. / Stressprotektornye svoistva novykh analogov mediatornykh aminokislot.

Stress-protective effect of phosphonglycerid and acyl analogs of neurotransmitter amino acids, which displayed nootropic activity was obtained. These compounds exerted positive influence on behavioral failure and morphological statement after 18-h immobilization. Dilithium-N-acetyl-L-aspartic acid (AKF-94) and di(3-dimethoxyphosphorylpropyl) ester of N-acetyl-DL-aspartic acid (PIR-87-6-0) displayed the most expressive activity. Previously activating influence of these compounds at excitatory amino acid transmission had been shown. We supposed participation of this way in stress-protective effect of new compounds.

Conjugates of natural compounds with nitroxyl radicals as a basis for creation of pharmacological agents of new generation.

Synthesis and research of pharmacological properties of polyfunctional "hybrid" compounds containing fragments of nitroxyl radicals (NR) in a molecule (spin-labeled conjugates) is a rapidly developing area of medicinal chemistry. Many examples of various classes of natural compounds have shown that the introduction of nitroxyl fragment into a molecule leads to either strengthening of biological activity or its modification, decrease of general toxicity, or increase of selective cytotoxicity. The review of the published data on spin-labeled biologically active natural compounds has revealed that various classes of natural compounds, such as anthracycline antibiotics, lignans, triterpene acids, chromanes, flavonoids, stilbenoids, alkaloids, amino acids, etc. are used for obtaining conjugates with nitroxyl radicals. Some spinlabeled derivatives of natural compounds are used for the treatment and prevention of the most dangerous diseases. Conjugates of nitroxyl radicals with "molecular compasses" (e.g. folic acid, fragments of gramicidin, heparin) may well serve as drug delivery systems to pathological areas of a body for diagnostics and treatment of diseases. We have summarized the results of the last decade on the synthesis and study of biological activity of conjugates with nitroxyl radicals.

Accelerated rejection of the second transplants of immunogenic tumor in mice under inhibition of indoleamine 2,3-dioxygenase activity by ethyl pyruvate.

AIM: A recently discovered enzyme, indoleamine 2,3-dioxygenase (IDO), is expressed in placenta, dendritic cells and also in many kinds of tumors and in tumor-infiltrating macrophages. By catabolizing tryptophan, IDO causes local depletion of this essential amino acid and excess of kinurenin, and suppresses in situ proliferation and functioning of T lymphocytes. Thus, immune resistance of tumors can be overcome by inhibiting IDO activity. MATERIALS AND METHODS: C3HA mice immunized with non-syngeneic H-29 tumor were used to study the effect of the IDO inhibitor ethyl pyruvate, under systemic or local (at site of tumor cells localization) administration, on the occurrence and rate of rejection of the second transplants of this tumor. RESULTS: Both systemic and local administration of ethyl pyruvate increases the incidence of and substantially accelerates tumor regression as compared with control. CONCLUSION: IDO inhibitors impairing immune resistance of tumors may appear useful in leveraging the efficacy of antitumor therapy.