[Dependence of the efficiency of cell growth on biosynthetic medical materials on the microstructure of their surface].

The efficiency of a novel class of biosynthetic wound dressings in wich natural and synthetic polymeric components are not arranged in layers but are in a unified structure, i. e., form a new composite material, has been studied. In particular, we tried to determine whether the interactions of dressing surface with cells of the injured tissue and/or culture grown in vitro depend on the microstructure of the surface. The efficiency of cell growth was considered in terms of the stimulation of cell growth. The microstructure of the surface was examined using the scanning electron microscopy at high resolution. The results of the study have shown that the structure of biosynthetic dressings depends on the variations in the composition and the ratio of the components. The role of the microstructure of the dressing in the effectiveness has been demonstrated. The factors which have the most significant effect on the regenerating properties of the wound dressings have been revealed.

[Nanocomposite regeneration systems for wound healing].

The regeneration system "Biokol" based on the principles of combining the synthetic and natural biopolymers has been investigated. The wound dressing consists of "large" (200-250 nm) particles of a synthetic biopolymer and a gel component, which constitutes "small" polysaccharide elements 10-20 nm in size. The system can be used both separately and in combination with the gel complex and cell cultures. In properties (vapor and gas permeability, mechanical properties, prokhodimost conductivity, resistance to microbes, etc.), it corresponds to the upper layer of the skin. When applied to the wound, the dressing changes its adhesiveness: first, owing to its hydrophilicity and low hydrophobicity, it closely adheres to the wound surface, and after some time, which corresponds to the time the polysaccharide complex is released from the dressing, it becomes hydrophobic and easily separates from the wound. Owing to these properties, the system can be used at all stages of the wound healing.

[Controlled cell culture. I. A modified perfusion chamber]. / Upravliaemoe kul'tivirovanie kletok. I. Modifitsirovannaia perfuzionnaia kamera.

The construction of a modified perfusion chamber is presented, which can be used for a prolonged cultivation of mammalian cells and tissues, for observation of the behavior of living cells as well as for the study of different effects on these cells. The chamber is made as non-demountable of optical glass, with a diffusive barrier separating the pericellular zone from that with a perfusion medium. The scheme of the equipment for cultivation of cells and tissues in this diffusion chamber on controlling the composition of nutrient medium and gas phase is given.

[Age-related changes in the growth-stimulating effect of serum on BHK-21 cells]. / Issledovanie vozrastnogo izmeneniia roststimuliruiushchego vliianiia syvorotki na kletki BHK-21.

The growth-stimulating effect of two calf and adult animal serum ultrafiltrates (with molecular weight of the components up to 100 000 dalton) on BHK-21 cells has been compared. The growth-stimulating activity of the calf serum ultrafiltrate was much greater. Aggregation of cells--the result of their reduced adhesion to the substrate--was much less pronounced in the presence of the calf serum ultrafiltrate than in the medium with the serum ultrafiltrate of adult animals. The data obtained show that the components containing in the studied ultrafiltrates (mol/wt up to 100 000 dalton) and not gamma-globulins (mol/wt 150 000 dalton), as it was considered earlier, primarily determine the ageing change of growth-stimulating activity of the serum. It should be suggested that the different influence of ultrafiltrates on cell adhesion is due to the presence of factors of adhesion with molecular weight up to 100 000 dalton in the calf serum and to its absence in the serum of adult animals.

[Presence of supposed growth factors in a serum fraction with a molecular weight of the components from 100,000 to 200,000 D]. / O prisutstvii predpolagaemykh rostovykh faktorov vo fraktsii syvorotki s molekuliarnym vesom komponentov ot 100 000 do 200 000 D.

Growth of cell culture BHK-21 in the presence of different fractions of bovine serum has been studied. Growth-promoting activity of the fraction with molecular weight of 100 000 daltons increased with the concentration of this fraction in the medium, but did not reach the activity level of the whole serum. The intensity of cell proliferation similar to that in the presence of the whole serum was achieved due to the combined action of the serum fraction with molecular weight of 100 000 - 200 000 daltons, containing the supposed growth factors and a fraction with low-molecular components of 14 000 daltons. When tested individually, neither of these two fractions showed similar effect.

[Growth of continuous and primary cell cultures on a liquid surface]. / Rost perevivaemykh ipervichnykh kul'tur klotok na zhidkoi poverkhnosti.

A possibility to culture reinoculated BHK-21 cells and primary human embryo fibroblasts on the surface of liquid fluorocarbon is shown. Two types of growth of BHK cells on liquid surface can be distinguished: with the spreading of cells on the surface and formation of a monolayer, and with growth without cell spreading and with accumulation of cells in the form of clusters and small groups. Adhesion of cells to the liquid fluorocarbon surface is found to be weaker compared to the reproduction on the solid surface.

[Arrest of BHK-21 cell culture growth and its stabilization in a resting state as affected by serum fractions]. / Ostanovka rosta kul'tur kletok BHK-21 i ikh stabilizatsiia v sostoianii pokoia pod deistviem syvorotochnykh fraktsii.

By cytofluorometry the distribution of cells was studied according to the amount of DNA in a population of BHK-21 cells placed in the media containing a serum fraction that either does not stimulate cell proliferation, or stimulates it until reaching 60% of the limiting density observed in the control. The analysis of cell distribution shown that after the arrest of cell growth cells are accumulated in the G1 phase of the cell cycle to change into the quiescent state. As a control, cytofluorometric analysis of populations of BHK-21 cells cultured under normal conditions in the presence of the 10% whole serum was performed.

[Growth-stimulating effect of serum ultrafiltrates on BHK-21 cells]. / Issledovanie roststimuliruiushchego vliianiia ul'trafil'tratov syvorotki na kletki BNK-21.

The growth of BHK-21 cells exposed to various bovine serum ultrafiltrates has been studied. The intensity of cell multiplication equal to that seen in the presence of the whole serum was provided only by the ultra filtrate containing all components with molecular weights up to 200 000 dalton. Ultrafiltrates containing components with molecular weight up to 70 000 dalton or from 70 000 to 200 000 dalton provided stretching of cells and their partial multiplication. Ultrafiltrates containing components with molecular weight up to 14 000 dalton stimulated only attachment of cells, without stretching.

[A study of the effect of irradiation hardness on the properties of the fluoropolymeric matrix modified by polyanionic biologically active substances]. / Izuchenie vliianiia zhestkosti oblucheniia na svoistva ftropolimernoi matritsy, modifitsirovannoi polianionnymi biologicheski aktivnymi veshchestvami.

The properties of a synthetic substrate responsible for the behavior of substrate-dependent cells in the culture were studied. The effect of the composition of a system water-soluble biopolymer (sodium alginate or methyl cellulose)-synthetic latex SKF-26 and the effect of various types of radiations on its biophysical properties were studied. The results obtained indicate that the addition of water-soluble biopolymeric additives to synthetic polymeric films improves the adhesion of cells to the substrate, the adhesion being closely related to the concentration of additives. It was found that the modification methods that determine changes in the charge of the substrate affect the capacity of different cell types for adhesion and proliferation. It was also found that the hardness of irradiation does not affect the vapor permeability and the extent of film swelling.

[Formation of collagen type I fibrils in vitro]. / Issledovanie obrazovaniia fibrill kollagena tipa I in vitro.

The assembly of collagen fibrils as a function of temperature and collagen concentration was studied. It was shown that temperature increases from 25 to 35 degrees C, the degree of ordering of collagen fibrils increases 1.5-fold at collagen concentration above 1 mg/ml and 2-fold at low collagen concentration. A maximum ordering of fibril structure occurs under conditions close to physiological (T approximately 35 degrees C and collagen concentration 1.2 mg/ml). As temperature is elevated from 30 to 35 degrees C, the packing of collagen molecules in fibrils becomes more ordered: the values of enthalpy and entropy of the transition of fibrils from the native to a disordered state decrease at all collagen concentrations used. At high collagen concentration, the dimensions of cooperative blocks in fibrils formed at 25 and 30 degrees C coincide with those of cooperative blocks of monomeric collagen in solution. Upon increasing the temperature to 35 degrees C, the dimensions of cooperative blocks increase.

[Self-assembly of collagen type I molecules without telopeptides]. / Izuchenie samosborki molekul kollagena tipa I s udalennymi telopeptidami.

The effect of temperature on the kinetics of formation of fibrils from rat tail collagen molecules devoid of telopeptides was studied. It was shown that the rats of fibril formation at 30 and 35 degrees C increases five- and eightfold, respectively, as compared with that at 25 degrees C. It was found that enthalpy of fibril denaturation at 30 degrees C is maximal for the collagen both with intact telopeptides and devoid of telopeptides. It was found that essential for the fibrilogenesis of type I collagen devoid of telopeptides are temperatures of 30 and 35 degrees C.

[Collagen gels, chondroitin-4-sulfate. Proteolytic stability]. / Kollagenovye geli, khondroitin-4-sul'fat, ustoichivost' k proteolizu.

Differential scanning microcalorimetry and polarized thermomicroscopic methods were used for studying of collagen type I and chondroitin-4-sulfate complexes. It was shown that fast heating till 37 degrees C lead to collagen gel formation, which is stable for collagenase action.

[Dynamics of spontaneous beating of cardiomyocytes in vitro depend on the number of involved cells]. / Izmenenie dinamiki sokrashchenii kardiomiotsitov in vitro pri uvelichenii chisla vzaimodeistvuiushchikh kletok.

The dynamics of cardiomyocyte spontaneous beatings with fractal dimension calculation was studied. It was shown that isolated single cardiomyocyte beats stochastically, but when a number of cells synchronized a significant changes in the dynamics appear: deterministic chaos could be detected. Several reasons are discussed as a possible explanation of such a behavior: the effect of system volume increasing and specific influence of gap-junctions on the rhythm formation.

[Effect of thermoreverse polymer matrix and collagen on the growth of human fibroblasts]. / Vliianie matriksa na osnove termoreversivnykh polimerov i kollagena na rost fibroblastov cheloveka.

The effect of a support composed of polymers based on poly-N-isopropyl acrylamide and poly-t-butyl acrylamide and collagen on human fibroblasts was studied. As the temperature was decreased to 4 degrees C, the polymeric support is converted to a diluted state and cells spontaneously detached from it. The presence of collagen in the support prevented the detachment of cells and increased cell growth. It was shown by microcalorimetry, that in a copolymer-collagen mixture, a microstratification takes place.