Investigation of the Binding of Lectins with Polymer Glycoconjugates and the Glycoconjugates Containing Silver Nanoparticles by Means of Optical Spectroscopy and Light Scattering.

The synthesis of glycoconjugates, lectin-specific polymers containing a carbohydrate ligand (spacered residue of N-acetyl-D-glucosamine, ß-N-Gly-GlcNAc) has been carried out. Glyconanoparticles (glycol-NPs) containing a label detectable by means of spectrophotometry, silver nanoparticles, have been prepared on the basis of the glycoconjugates. Copolymers of maleic anhydride with ethylene or N-vinylpyrrolidone have been used as a carrier to introduce the carbohydrate ligand and a stabilizer of silver nanoparticles. Solutions of the glycoconjugates and the silver glyconanoparticles have been characterized by means of light scattering, UV-visible spectroscopy, and TEM. The interaction of the obtained glycoconjugates and silver glyconanoparticles with N-acetyl-D-glucosamine-specific lectins of Solanum tuberosum agglutinin (STA) and wheat germ agglutinin (WGA) has been investigated by means of light scattering and UV-visible spectro-scopy. The data obtained via these physical methods using the carbohydrate-containing derivatives labeled with silver nanoparticles have been in agreement. It has been shown that the glycoconjugates and silver glyconanoparticles based on more hydrophilic copolymer of maleic acid with N-vinylpyrrolidone are more sensitive than the respective systems based on more hydrophobic copolymer of maleic acid with ethylene. It has been also shown that the considered systems are more sensitive to the STA lectin than to the WGA lectin. The silver glyconanoparticles have allowed more accurate and reliable detection of the lectins by means of light scattering, as compared to the glycopolymer.

[Biospecific properties of lysine-contained polyelectrolyte coatings for devices contacting blood].

Biospecific properties of thromboresistant bilayer and multilayer coatings based on polyelectrolyte complexes of modified copolymer of N-vinylpyrrolidone and maleic acid (VPMA) with chitosan, amphiphilic chitosan or albumin were investigated. VPMA contained affinity ligand towards plasminogen--alpha-amino coupled lysine residues. Polyethylene and polystyrene surfaces were investigated before and after their covering by protective polyelectrolyte coatings. The specific adsorption of plasminogen (precursor of the fibrinolytic enzyme plasmin) from its solutions and from human plasma was investigated using these model systems. It was found that all coatings with the outer contact lay of lysine-contained affinity polymer had affinity to plasminogen. But multilayer polyelectrolyte coatings were more efficient than bilayer coatings with single application of layers and the affinity polymer coatings without interlayer. The decrease in trombogenicity degree of the materials modified by polyelectrolyte coatings was shown in vitro and ex vivo. Emplyment of proposed modification of surfaces will improve hemocompatibility of medical devices.

[New liposomal forms of antifungal antibiotics, modified by amphiphilic polymers].

A method has been developed, for incorporating macrocyclic polyene antibiotics nistatin and amphotericin B into liposomes containing phosphatidylcholine and cholesterol (7:3) or phosphatidylcholine, cholesterol, and cardiolipin (7:3:1), the membranes of which were modified with an amphiphilic polymer of N-vinylpyrrolidone, carrying one terminal n-octadecyl group and having a molecular weight of 4000 Da. The amount of antibiotics within such liposomal nanocarriers may be as high as 17-22%. It was demonstrated that the modified liposomes have sizes in the range 150-200 nm and exhibit increased long-term storage stability and increased resistance to disrupting agents (Triton X-100 or ethanol) and ultrasound. The antifungal activity of the liposomal preparations obtained exceeded that of the antibiotics not subjected to immobilization.

[Sorption of wheat seed lectin by polyelectrolyte complexes of chitosan]. / Sorbtsiia lektina zarodyshei pshenitsy poliélektrolitnymi kompleksami khitozana.

The possible application of polyelectrolyte complexes (PEC) of chitosan and copolymers of maleic acid with N-vinylpyrrolidone, styrene, and ethylene and/or chitin cross-linked sorbents (CCLS) synthesized on the basis of PEC for sorption of wheat germ agglutinin (WGA) was studied. The synthesis of spherically granulated sorbents was shown. Compared to unmodified chitosan, there was a significant increase in sorption of WGA by the PEC: PEC, 2.5-fold, and CCLS, from 3.5-fold to 7-fold.

[An enterosorbent with trimethylaminoethanol chloride. 2. Hypolipidemic action and effect on cholesterol absorption in the intestine (experimental data)]. / Enterosorbent s immobilizovannym khloridom trimetilaminoéthanola. 2. Gipolipidemicheskoe deistvie i vliianie na vsasyvanie kholesterina v kishechnike (éksperimental'nye dannye).

Enterosorbent containing trimethyl aminoethanol chloride administered per os into rabbits accelerated the rate of experimental hypercholesterolemia regression. Moreover, this substance decreased 4-14C-cholesterol absorption in the rat intestine.

[Enterosorbent with immobilized trimethylaminoethanol chloride. I. Hypolipidemic properties]. / Enterosorbent s immobilizovannym khloridom trimetilaminoétanola. I. gipolipidemicheskie svoistva.

Hypolipidemic properties of the synthesized enterosorbent, water soluble polymer containing covalently immobilized trimethylamine ethanol chloride, were studied. Content of cholesterol in blood was decreased by 29% and accumulation of cholesterol in liver tissue--by 22% after oral administration of the enterosorbent at a dose of 250 mg/kg into rats with hypercholesterolemia. Cholestyramine exhibited the similar effect only at a dose of 2.5 g/kg. Except for the hypocholesterolemic effect, the enterosorbent altered also the lipoprotein spectrum in rat blood serum.

[The effect of water-soluble sorbents on the exocrine function of the liver]. / Deistvie vodorastvorimykh sorbentov na vneshnesekretornuiu funktsiiu pecheni.

The effect of water-soluble sorbents on exocrine function of the liver was studied in chronic experiments on 2 dogs with a brought out bile duct. It is shown that choline and digitonin sorbents exhibit choleretic properties similar to those of cholestyramine. Choline sorbent causes a drop in the concentration of (2-4-fold) cholic acid in the bile unlike digitonin sorbent. No prolonging action was seen upon cholestyramine administration, while choline sorbent do demonstrate it. Cholesterol and bilirubin levels do not respond noticeably to the above sorbents.

[A study of hydrolysis of various synthetic peptides with gastrointestinal enzymes using thin-layer chromatography]. / Issledovanie gidroliza nekotorykh sinteticheskikh peptidov fermentami zheludochno-kishechnogo trakta metodom tonkosloinoi khromatografii.

Hydrolysis in vitro of alpha- and epsilon-peptide bonds of synthetic amino acids and peptide substrates,--models of protein fragments, with digestive enzymes was studied. The kinetics of hydrolysis was studied by quantitative thin-layer chromatography followed by densitometric analysis of the chromatographic patterns. The rate constants of hydrolysis of Phe-Lys, Gly-Lys dipeptides and their epsilon-acetyl and epsilon-succinyl derivatives with leucine aminopeptidase and pancreatic enzymes were calculated. epsilon-Acyl residues of the substrates failed to split off under these conditions. The digestive enzymes hydrolysed the alpha-peptide bonds adjacent to the acylated lysine. Hydrolysis of epsilon-acetyl substrates proceeded faster as compared to epsilon-succinyl derivatives.

[Synthesis and properties of an affinity sorbent for extraction of atherogenic lipoproteins]. / Sintez i svoistva affinnogo sorbenta dlia izvlecheniia aterogennykh lipoproteinov.

A digitonin-containing affinity sorbent was prepared using a hydrophilic polymer carrier. The correlation was found between the polymer structure and crosslink. King degree, on the one hand, and the sorbent capacity to bind cholesterol, protein and lipoproteins--on the other. The sorbent was demonstrated to extract predominantly atherogenic lipoproteins from blood plasma.

[Excitatory effect of tuftsin tetrapeptide on the activity of white rats]. / Vozbuzhdaiushchee deistvie tetrapeptida tuftsina na aktivnost' belykh krys.

Studies on male white rats have shown that tuftsin (trelys-pro-arg) enhances the locomotion in animals as disclosed by a series of the behavioral tests. The effect is dose-dependent: a dose of 50 microgram/kg did not change any of the test parameters, while that of 150 microgram/kg induced a short-term elevation of locomotion measured with an "Animeks". Administration of tuftsin in a dose of 300 microgram/kg led to the enhancement of the animals' locomotion as measured with the "Animeks", to the increased "open field" running time and to the reduced latent period of the reaction during the training in a T-shaped maze. Also, this dose of the peptide relaxed the reactions associated with fear. It is assumed that the effects observed are consequent on the stimulant action of tuftsin on the body of white rats.