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Biomedical subjects

S M Bychkov

Publications and source records attributed to S M Bychkov.

At least 37 records · Page 2Linked to original sources

[Comparative study of the IR-spectra of glycosaminoglycans and their monomers].

The infrared spectra of hyaluronic acid (HA), protein chondroitin keratan sulfate (PCKS), aggregates of proteoglycans (AP), glucuronic acid and its potassium salt, glucosamine, galactosamine (both as hydrochlorides), N-acetyl-glucosamine, N-acetyl-galactosamine, ammonium salt of N-acetyl-neuraminic acid were obtained in the region 200--4000 cm-1. It was shown that comparative analysis of the spectra of the monomers and their mixtures with those of HA, PCKS and AP makes it possible to identify more precisely a greater number of absorption bands as compared to that identifiable on examining but the spectra of these biopolymers. The interpretation of the results obtained is presented.

Animals↗

[Study of various heparin salts].

The methods for preparing acid and neutral Na+, K+, Ca2+ and Mg2+ salts of individual heparin fractions were devised. One of the fractions contains 3 (HP = 3) and another 4 (HP = 4) sulfate groups per dimer of the macromolecule of both the polymers. Infrared spectra of the salts were obtained. It was shown that acid salts of HP = 3 (with the exception of Mg2+ salt) and HP = 4 form intermolecular hydrogen bonds. The structure of the infrared spectra of HP = 3 and HP = 4 salts depends, to a significant degree, on the cation nature.

Chemical Phenomena↗

[Infrared spectra of certain proteoglycans].

IR spectra of high-purified potassium salts of hyaluronic acid (HA), non-aggregation fraction of protein-chondroitin-keratan sulfate (PChKS) and heparin fractions containing 3 (H-3) and 4 (H-4) residues of sulfuric acid per dimer of polymer have been measured. An absorption band of 1150 cm-1 has been observed in the spectra of both HA and PChKS but has not been found in the spectra of H-3 and H-4. Observation of this band in the spectra of some heparin preparations indicates that they contain the admixtures of HA, PChKS and other proteoglycans. A previously suggested method for isolation of heparin fractions H-3 and H-4 makes it possible to obtain preparations that do not contain the admixtures of other proteoglycans.

Animals↗

[Infrared spectra of cartilage proteoglycans].

Infrared spectra of protein-chondroitin-keratan sulfate (PCKS) and proteoglycans aggregates (PA) isolated from trachea cartilage of cattle have been examined. Proteoglycans have been shown to be completely detectable in this tissue by infrared spectroscopy. This method can be applied for determining the degree of PCKS and PA extraction from the cartilage.

Animals↗

[Electron microscopic study of isolated proteoglycans].

Chemically isolated separate preparations of the non-aggregating protein-chondroitin-keratin sulphate (PCKS) fraction from the hyaline cartilage and hyaluronic acid (HUA) of the vitreous body and of the umbilicus were investigated by electron microscopy. PCKS and HUA in films without cytochrome c were present in the form of granules and differed by structural organization. The proteoglycans of the cytochrome c films were seen as finely-filamentous-cellular network, and were distinctly differentiated by their macromolecular organization. A mixture of both proteoglycans formed complexes as a result of a noncovalent interaction. Uranyl acetate ensured a good contrasting of proteoglycans, especially of PCKS, without cytochrome c.

Acetates↗

[Joint action of protein-chondroitin-4-keratan-sulfate and hyaluronic acid on erythrocyte aggregation and adhesion].

It was shown that the rate and the degree of erythrocytes aggregation brought about by a mixture of protein-chondroitin-4-keratan sulfate (PCKS) and hyaluronic acid (HA) was greater than the sum of the values of the corresponding indices observed during separate independent action of these proteoglycans on the aggregation of the mentioned cells concentrations as in the mixtures. It may be supposed that such phenomenon is connected with formation in the mixture of a hybrid PCKS-HA complex which is more active in respect to the erythrocyte aggregation than its components separately.

Cell Adhesion↗

[Role of glycosaminoglycans and proteoglycans in erythrocyte aggregation and adhesion].

The action of hyaluronate potassium (HUK) and of protein chondroitin-4-sulphate potassium (PCHSK) on the aggregation and adhesion of rabbit erythrocytes suspended in physiological saline was studied. It was found that the capacity of HUK and PCHSK to produce an unspecific and reversible aggregation of erythrocytes was connected with the formation by these biopolymeres (in solutions) of complex structures of osmotic cell type and molecular sieves, displacing cells from the space occupied by them and concentrating them in a maximally limited volume. Different heparin fractions producing no such structures in solutions did not induce formation of such individual clear-cut erythrocyte-aggregations, but inhibited the aggregating action of HUK and PCHSK when the concentration of these biopolymeres were inadequate for the complete erythrocyte aggregation. Probably, the aggregating action of HUK and PCHSK necessary for adhesion served as one of the universal biological functions expressed not only towards the erythrocytes, but also towards the other cells and different tissue structural elements.

Animals↗

[Structural-mechanical properties and swelling of the protein complexes of hyaluronate and protein-chondroitin-4-sulfate].

It was shown that the mechano-structural strength and swelling of gels consisting of gelatine and potassium hyaluronate (PH) or potassium protein-chondroitin-4-sulphate (PPCS) depended on the correlation of the components. Low PH and PPCS concentrations showed a minimal mechano-structural strength and a maximal swelling of gels. In the zones of neutralization of the positive electrical charges of gelatine by macropolyanions a high mechano-structural strength coincided with a minimal swelling. With high PH concentrations the mechano-structural strength and swelling of gels became equal to those of pure gelatine; and with high PPCS concentrations there was noted an additional parallel increase in the strength and swelling of gels.

Animals↗

[Different heparin fractions].

It was shown that treatment by 2-3 M KCl solutions of complex unfractionated preparations of heparin with hexamminecobalt (III) resulted in incorporation into the solution of a heparin fraction containing 3 residues of sulphuric acid per 1 residue in glucosamine. In the precipitate released of hexamminecobalt (III) there remains a heparin fraction containing 4 residues of sulphuric acid per 1 residue of glucosamine. Both fractions were isolated in a chemically individual form.

Chemical Phenomena↗

[Biological role of hyaluronic acid (review)].

The most important studies on hyaluronic acid carried out within the recent 5-7 years are reviewed. Chemical structure, physical parameters and properties of hyaluronic acid are considered. Various functions of hyaluronic acid are discussed on the basis of current information.

Animals↗