[Modification of collagen during action light].

In work chemical modification of collagen during action visible spectrum sunlight. These changes of collagen were found to indicate a photodegradation and photooxidation processes in collagen.

[Biochemical and photometric studies of modification of collagen structure under UV radiation].

The influence of UV irradiation (270-380 nm) on the biochemical, fluorescence and colorimetric properties of collagen was studied. The long-term UV irradiation (120 h) was accompanied by the increase of structural stability of collagen to specific and nonspecific proteolytic enzymes, by formation of new additional fluorophore-containing molecules, by the increase in quantity of carbonyl groups in the collagen and by strong changing of the distribution pattern of alkaline hydrolysis products during gel-chromatography. The coordinates of colour of the collagen films are also changed. These changes of collagen suggest that UV irradiation induces photomodification and photooxidation processes in collagen.

Biochemical indexes of the skin and blood melatonin concentration in rats during acute stress and treatment with exogenous melatonin.

We studied the effect of acute stress on serum melatonin concentration, content of major components in the connective tissue (uronic acids, hexosamines, and hydroxyproline), and beta-galactosidase activity in the skin of rats with different activity in the open-field test receiving intraperitoneal injections of physiological saline or melatonin. Acute stress intensified catabolism of carbohydrate components and affected characteristics of the main skin biopolymers. The content of uronic acids in connective tissue carbohydrates decreased. Collagen structures of the skin underwent less pronounced changes. The observed changes were similar in behaviorally active and passive animals. Administration of melatonin increased the contents of uronic acids and hexosamines in the skin. Pretreatment with melatonin prevented the decrease in the content of glycosaminoglycans in rat skin during acute stress.

Water status and LPO in rat tissues during massive blood loss and irradiation with He-Ne laser.

We revealed a relationship between water balance and LPO in the myocardium, liver, and blood plasma during massive blood loss and irradiation with He-Ne laser. Low-intensity laser irradiation of the plasma inhibits LPO and normalizes water balance in rat tissues during massive blood loss.

Comparison of cytotoxicity of aminoglycoside antibiotics using a panel cellular biotest system.

The cytotoxicity of four aminoglycoside antibiotics was studied by estimation of the dose-effect relationship using a panel cellular biotest system including cell cultures for test objects. The cultures represented 4 differentiation types: normal human fibroblasts and myoblasts, human or Syrian hamster hepatoma cells, and mouse/mouse hybridoma cells. It was found that three widely used antibiotics gentamicin, kanamycin, and neomycin exhibit similar, but not identical cytotoxicity parameters and differ distinctly from geneticin. Hence, the proposed panel biotest system helps to quantitatively evaluate and differentiate the effects of bioactive substances with similar chemical structure.

[Various forms of water in the rat myocardium and liver during blood loss and the early postresuscitation period]. / Zakonomernosti izmeneniia razlichnykh form vody v miokarde i pecheni krys pri krovopotere i v rannem postreanimatsionnom periode.

Different forms of water content were studied in myocardium and liver of male rats at 2-h hypotension and during the early postreanimation period. The phenomenon of redistribution of free and bound water was found. Comparison of water balance during the postreanimation period in the myocardium and liver revealed that normalization of different forms of water occured in myocardium. In hepatocytes oedema remained over the whole period studied.

Structural modification of collagen during nonenzymatic glycosylation in vitro.

We studied changes in collagen resistance to proteases and formation of new fluorescent compounds during in vitro nonenzymatic glycosylation. The inhibitory effects of guanidine chloride and catalase were different: guanidine chloride inhibited cross-linking in collagen molecules, while catalase inhibited the formation of chromophore-containing compounds.

Some biochemical characteristics and water exchange in human articular cartilage in osteoarthrosis.

Rearrangement of intra- and intermolecular bonds in collagen molecule, disaggregation of proteoglycans and their elimination from cartilage involved in osteoarthrosis are responsible for water accumulation and its increased mobility in cartilage.

[Study of the antiradical and radioprotective properties of S-containing compounds using the complex of in vitro test-systems]. / Izluchenie antiradikal'nykh i protivoluchevykh svoistv S-soderzhashchikh soedinenii s ispol'zovaniem kompleksa test-sistem in vitro.

Capability of S-radioprotectors (AET, 2-AT, 2-ADT) to react with OH-radicals and to protect various molecular biotest systems against radiation damage was compared with that of 5-methoxytryptamine, some amino acids and t-butanol. A method of competing acceptors was used to determine rate constants in reactions of the radioprotectors with OH-radicals. A complex of biotest systems (protein, DNA, protein-lipid complex) was applied to estimate the radioprotective activity in vitro. It was found that the studied S-compounds are capable of modifying the protective effect as compared to the expectation from the competitive kinetics approach. Both enhancing and lessening of the effect was observed depending on the test system used. The obtained results can be explained by the impact of secondary radicals on the bio-target and/or by the interaction of the S-compounds with the bio-target that altered its radiosensitivity.

[Evaluation of preservation and the collagen structure state in the mummy tissues]. / Otsenka sokhrannosti i sostoianiia kollagenovykh struktur v tkaniakh mumii.

The content and state of collagen in skin, muscle and bone of 2500-year-old Altai mummies were studied. Collagen is the predominant protein in studied tissues of the mummies. High degree of the resistance of collagen to the effect of various proteases (collagenase, pronase, pepsin) and to alkline and acidic hydrolysis suggests on the considerable chemical modification of tissue collagen structures of the mummy. The possibility of increased collagen cross-linkages in tissues of the mummies during long-term storage and of nonenzymatic glycosylation of collagen leading to the formation an Amadori products and other modified structures are discussed.

Biochemical characteristics and water exchange in the surface layer of human joint cartilage.

We compared the contents of collagen, glycosaminoglycans, and various forms of water in the surface layer and whole tissue of joint cartilages of different localization. It was found that the surface layer is characterized by reduced content of glycosaminoglycans compared to the whole tissue and higher water-holding capacity due high content of bound water.

Cell culture test system for express analysis of cytotoxic and growth-stimulating effects of bioactive compounds.

Cultures of human and mammalian cells presenting 4 types of differentiation (normal human fibroblasts and myoblasts, human and Syrian hamster hepatoma cells, and mouse/mouse hybridoma cells) were used in a panel biotest system. This system allowed to evaluate the cytotoxic and stimulatory effect of bioactive compounds by determining the dose-effect relationships and some quantitative parameters including LD(50). Examination of some biolactive compounds of different nature (sangviritrin, escin, deltostim, cycloheximide, dexamethasone) confirmed high efficacy of this biotest system.

[Changes in biochemical characteristics of collagen and the cartilage water in osteoarthritis]. / Izmenenie biokhimicheskikh kharakteristik kollagena i sostoianiia vody khriashcha pri osteoartrite.

The stability of collagen molecules and moisture capacity of human normal and osteoarthrotic (OA) cartilage were studied before and after extraction of glycosaminoglycans (GAG) by 4M guanidinum chloride. The content and nature of water were determined by Fisher titration, DSC and analysis of sorbtion-desorbtion processes of water vapour in cartilage. The stability of collagen molecules was determined by the degree of enzymatic hydrolysis: collagenase, pronase and pepsin. It was found that weakening of bonds between main compounds of the cartilage matrix and decrease of GAG quantities in the OA cartilage were accompanied by structural disorganization of the collagen network, which is manifested by breakdowns of intramolecular bonds in telopeptides and intermolecular bonds in the spiral part of collagen molecules, these changes may contribute to increase of total water in OA cartilage. The correlation of free and bound water fractions in cartilage was increased from 5 to 44 in OA cartilage. These results can be used as a criterion of pathological condition of human articular cartilage.

Use of cultured human fibroblasts for rapid evaluation of cytotoxic effects of bioactive substances.

A test system for detecting cytotoxic effects of bioactive substances based on human fibroblast culture is proposed. The effects of acrylamide, streptomycin, cycloheximide, sodium dodecyl sulfate, sanguiritrine, and ethanol were evaluated by organic stain binding. Typical dose-effect relationships were detected for all substances except cycloheximide. The proposed test system can be used for screening of bioactive substances in preclinical trials.

[Water-exchange processes in hyaline cartilage and its basic components in a normal state and in osteoarthritis]. / Vlagoobmennye protsessy v gialinovom khriashche i ego osnovnykh komponentakh v norme i osteoartroze.

The content of different forms of tissue water was studied in the normal articular cartilage and osteoarthrosis cartilage and its structural components: collagen, potassium hyaluronate, sodium chondroitinsulphate and its complexes. In the components of cartilage matrix a few of fractions of bound water different in the strength of binding are present. At the maximal humidity, all water in collagen binds with the active groups of biopolymers and in the glycosaminoglycans, in addition to bound water, are present, two crystal forms of freezing water (free water) at least. The quantity of free water in the collagen-chondroitin sulphat membrane, is increased with the increase of chondroitin sulphate. In the collagen-hyaluronate complex, fraction of free water is found only at the low concentration of hyaluronate kalium. It was shown that in the hyalin cartilage, in different from the other connective tissue (skin, achilles tendon), the most part of water is free water and its quantity is increased in the osteoarthrosis. It is supposed that the rearrangement of binding and free-water fractions in the osteoarthrosis is the result of deficiency of hyaluronic acid and therefore this may be regarded in the improvement of methods of treatment. This scientific and methodical approach allow to receive information on the forms and binding energy of water in the biological tissues, which is absorbed from fluids and steam phase and determine characters of the pathological changes.

[Lipid parameters of the skin, cerebellum, and medulla oblongata during immersion stress in rats]. / Lipidnye pokazateli kozhi, mozzhechka i prodolgovatogo mozga pri vodno-immersionnom stress u krys.

The influence of short-form water immersion stress of rats on lipids in the skin, the cerebellum and the medulla oblongata was studied. The level of total lipids and absolute and relative contents of the main lipid fractions (phospholipids, nonesterified cholesterol, free fatty acids, triglycerides, and cholesterol esters) were measured. Stress induced delayed changes of the lipid component of the skin. The first significant changes of lipid fractions were only observed 20 h later after the stress procedure. These changes were retained (being at nearly constant levels) till the end of the second day. The decrease in contents of total lipids and esterified cholesterol was revealed in the cerebellum of stressed rats (in comparison to these levels in control rats). These results suggest the involvement of cholesterol metabolic system in the stress reaction. The content of total lipids decreased also in the medulla oblongata. However, levels of the main lipid fractions changed differently. The content of diglycerides increased and the content of cholesterol decreased. The data obtained suggest that degradation of triglycerides is the principle pathway of metabolic conversions of lipids. Free fatty acids formed during these processes are probably involved in the synthesis of phospholipids and cholesterol esters. The data indicate absolutely different mechanisms of interrelations between individual lipid fractions in the brain regions studied. Various roles of the brain structures in the stress response of the body may account for the differences revealed.