[Replication-competent γ-retrovirus Mo-MuLV expressing green fluorescent protein gene as an efficient tool for screening of inhibitors of retroviruses that use heparan sulfate as the primary cell receptor].

The effect of sulfated polysaccharides on the efficiency of infection of mouse embryonic fibroblast cell lines SC-1 and NIH-3T3 by replication-competent recombinant Moloney murine leukemia virus (Mo-MuLV) carrying the eGFP gene was investigated. It was shown that used polysaccharides have no cytostatic and cytotoxic effects on SC-1 and NIH 3T3 cells inthe concentrations from 0.01 to 100 µg/ml and have virucidal activity against Mo-MuLV. Polysaccharides in the indicated concentrations inhibit cell infection by Mo-MuLV, that prevents further expansion of viral infection. It was detected that sulfated polysaccharides are effective inhibitors of other retroviruses, including lentiviruses, that use heparan sulfate as cell receptors for non-specific binding.

[Macromolecular systems and bactericidal films based on chitin derivatives and silver nanoparticles].

A new polymer composite based on carboxymethylchitin and silver nanoparticles was obtained in order to produce biodegradable wound coating films. The number of metal nanoparticles in the composite may be easily regulated as was verified by UV-VIS-spectroscopy data. A comparative evaluation of silver nanoparticle size in the initial system and in the polymer composition was performed by means of photon correlation spectroscopy. Composite films revealed a pronounced concentration-dependent antibacterial activity towards strains Salmonella typhimurium and Staphilococcus aureus.

[Antimicrobial activity of core-sheath surgical sutures modified with poly-3-hydroxybutyrate].

To impart antimicrobial activity to surgical sutures, weaved polyester fibers are coated with poly-3-hydroxybutyrate (PHB), containing the antimicrobial agent furazolidone (FZ). The prolonged FZ effect (7-14 days) is achieved by two-step application of a sheath, constituting 10% of the suture weight and containing 2-6% FZ. The sheath structure and antimicrobial activity of sutures can be modified by the introduction of other biocompatible and biodegradable polymers.

[Preparation of biodegradable porous films for use as wound coverings].

We studied the preparation of polymeric films formed from solutions of poly-3-hydroxybutyrate and poly-epsilon-caprolactone in chloroform and methylene chloride. A morphological study of film chips (electron microscopy) showed that solvent evaporation results in the formation of a heterogeneous structure with interpenetrating pores (1-20 microm). We proposed a new method for introducing the proteolytic enzyme and the aminopolysaccharide chitosan into the composition of polyester films. Composite films possessed necrolytic activity and were characterized by increased hydrophilicity. Properties of enzyme-containing films from a mixture of polymers (proteolytic activity, porous structure, and increased hydrophilicity) account for their use in the preparation of biodegradable wound coverings.

[Hydrolysis of heparin by the immobilized enzymatic complex from Streptomyces kurssanovii]. / Gidroliz geparina immobilizovannym fermentnym kompleksom iz Streptomyces kurssanovii.

The possibility of obtaining low-molecular-weight heparins using the chitinolytic enzymatic complex immobilized on Silochrom has been demonstrated. The optimal conditions of this process (sodium acetate buffer, pH 7.0-7.5; temperature, 40-45 degrees C; and duration of hydrolysis, 3 h) were determined. Depending on the ratio between heparin and the immobilized enzymatic complex, samples with molecular weight varying from 1.7 to 4.7 kDa, were obtained. These complexes inhibited factor Xa in 2.0-3.7 times more effectively than original heparin.

[Hydrolysis of chitosan sulfate by an enzyme complex from Streptomyces kurssanovii]. / Gidroliz sul'fata khitozana fermentnym kompleksom iz Streptomyces kurssanovii.

The possibility of enzymatic hydrolysis of chitosan was shown. The optimum conditions for the process are: sodium acetate buffer pH 6.0, 37 degrees C, 24 h, and the chitosan sulfate-protein volume ratio of 500:1 in the enzyme preparation. During hydrolysis, the intrinsic viscosity of chitosan sulfate solution decreased by a factor of 2.7.

Comparison of antithrombin activity of the polysulphate chitosan derivatives in in vivo and in vitro system.

In order to choose the proper method for evaluating the antithrombin activity in samples of chitosan polysulphate (CP) with different polymerization degrees and sulphation degrees, we estimated the ability of direct anticoagulants to depress the coagulability of recalcified sheep blood using the third international heparin standard (A1 - in vitro system) and determined such activity on pharmacodynamic curve (A2 - in vivo system). The curve admits the kinetics of CP elimination to be nonlinear in case of intravenous injection to rabbits, as it is observed in heparin: Ct = C(o)exp(-K(e)lt), where Ct is the CP concentration at the time moment t; C(o) is the CP concentration at the injection moment; Kel is the elimination constant. Besides, it is assumed that there is a linear approximation of the anticoagulant effect on the dose, which finally makes it possible to calculate the specific activity A2: T = KTCt+T(in), where T is the time of clot formation at different time intervals after CP injection; T(in) is the time of clot formation prior to CP injection. T value was assessed in two tests: blood coagulation time (BCT) and activated partial thromboplastin time (APTT). No correlation was observed between A1 and A2. At the same time, the values of Kel and the period of semi-elimination, with the use of the biospecific cetylpyridinium chloride electrophores for the quantitative determination of CP in rabbit's blood taken at different time intervals after injection, showed a close correlation (r = .94, P < .05) between the same parameters, obtained with the help of the rectilinear pharmacodynamic plot in BCT test. Thus, experimentally, it was proven that the assumption of the CP nonlinear elimination and the CP effect-dose dependence was true, which is necessary for A2 calculation. Relatively low molecular weights (MW 61-82 kDa, polymerization degree 188-252 ) and high sulphation patterns (sulphur amounts 15.6-16.9%, sulphation degree 1.58-1.86) were slowly cleared and there was more antithrombin activity (30-52 IU/mg). We recommend the use of in vivo system for evaluating the antithrombin activity of the CP derivatives.

[The effect of the joint administration of heparin and chitosan sulfate ether on hemostatic function]. / Vliianie sovmestnogo vvedeniia geparina i sernokislogo éfira khitozana na funktsiiu gemostaza.

We studied anticoagulant effects of combined administration of heparin (H) and chitosan sulfate ether (CS) (specific activity 20 UE/mg) in the ratio 1 : 1. CS enhanced anticoagulant activity of heparin in rabbits by a factor of 1.95 +/- 0.15. The intravenous injection of the mixture in a dose of 0.5 mg(H)/kg + 0.5 mg(CS)/kg and heparin injection in a dose of 1mg/kg induced the same effect. Haemorrhagic effect of this mixture was less pronounced compared to heparin, anticoagulant and antithrombotic activities remained the same. The mixture was found to decrease a number of platelets, however, this was also less pronounced compared to heparin. Thus, the use of the mixture CS + H (1 : 1) instead of double heparin dose resulted in the same effect.

[The relation between the physicochemical structure and the anticoagulant effects of polysulfated chitosan derivatives]. / Sviaz' fiziko-khimicheskoi struktury i antikoaguliantnykh éffektov u proizvodnykh polisul'fatirovannogo khitozana.

Rabbit experiments have revealed that there is a relationship between the chemical structure and anticoagulative effects of polysulfated chitosan derivatives. Sixteen chitosan polymers with a polarization rate of 71 to 547 and substitution by sulfur from 0.62 to 1.86 which were intravenously injected showed heparin-like action. The anticoagulant activity of chitosan samples depended on the degrees of polymerization and sulfation. The most active (30-52 U/mg) and long-acting (250-350 min) products had a polymerization in the range 180-240 and sulfation no less than 1.5, the half-life being 37-50 min, and the elimination constant being 1.38.10(-2) to 1.88.10(-2)min-1.

[Effect of chitosan sulfates on lipoprotein lipase activity]. / Vliianie sul'fatov khitozana na aktivnost' lipoproteinlipazy.

Effect of commercially available preparations of chitosan sulfate on the total lipolytic activity was studied in rabbit blood. Chitosan sulfates, administered per os or intravenously, proved to be highly effective activators of lipolytic enzymes. The most distinct efficiency exhibited preparations with molecular mass of 60-120 x 10(3) and the rate of sulfation 1.20-1.35. After administration of the chitosan sulfates into hyperlipidemic rats a decrease in blood plasma VLDL and increased HDL content were observed.