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Biomedical subjects

I A Khlusov

Publications and source records attributed to I A Khlusov.

At least 19 recordsLinked to original sources
PubMed2006

Relationship between osteogenic characteristics of bone marrow cells and calcium phosphate surface relief and solubility.

The capacity of mouse bone marrow cells to adhere to calcium phosphate surfaces and form tissue plates depending on the surface relief and solubility was studied in ectopic bone formation test. Calcium phosphate coating of titanium disks, made by the anodic spark (microarch) oxidation in 10% orthophosphoric acid with hydroxyl apatite particles, differed by the structure (thickness of coating, size of pores, and roughness) and solubility (level of in vitro oxidation of 1-week extracts of implants). Chemical (phasic and element) composition of the studied calcium phosphate coatings was virtually the same. The findings indicate that histogenesis is regulated by physicochemical characteristics of the implant surface. It seems that the osteogenic potential of calcium phosphate surfaces is largely determined by their relief, but not by pH of degradation products.

Animals↗
PubMed2006

A hybrid PHB-hydroxyapatite composite for biomedical application: production, in vitro and in vivo investigation.

Samples of a hybrid composite of polyhydroxybutyrate (PHB), a biodegradable polyester, and hydroxyapatite (HA), with different PHB/HA ratios, have been prepared using mechanical-physical method. Electron microscopy, X-ray structure analysis and differential thermal analysis have been used to investigate the structure and physicochemical properties of the composite, depending on the PHB/HA ratio. The properties of the surface of the HA-loaded composite are significantly different from those of the pure polymer. As the HA percentage in the composite increases, free interface energy, the cohesive force, i.e., the strength of the adhesive bond between the composite surface and the water phase, and surface wettability increase. The HA percentage of the composite does not influence its melting temperature, but affects the temperature for the onset of decomposition: as the HA content increases from 0 to 10% (w/w), Td decreases from 260 degrees C to 225 degrees C. The degree of crystallinity of PHB/HA increases from 77% to 89% with an increase in the HA fraction from 10% to 50%. Functional properties of the composites have been investigated in vitro and in vivo. The best parameters of growth and differentiation of murine marrow osteoblasts are registered on PHB/HA samples containing 10% and 20% HA. In ectopic bone formation assay it has been proven that the hybrid PHB/HA composites can function as scaffolds and that bone tissue develops on their surface and in pores.

Animals↗
PubMed2005

Morphofunctional characteristics of blood mononuclear cells during in vitro culturing under dynamic conditions.

The primary culture of human blood mononuclear cells was incubated on fibrous membranes under a constant directional flow of the nutrient medium modulating intraocular fluid flow. Incubation was performed for 24, 48, and 72 h. Intracellular enzyme activity of mononuclear cells increased under dynamic conditions. Differentiation of blood monocytes and circulating fibroblast precursors into macrophageal cells and mature cells, respectively, was accelerated.

Alkaline Phosphatase↗
PubMed2005

Osteogenic potential of mesenchymal stem cells from bone marrow in situ: role of physicochemical properties of artificial surfaces.

Correlation analysis demonstrated the role of inorganic parameters of the surfaces of calcium phosphate materials in the regulation of osteogenic differentiation of mesenchymal precursors. The progenitor stromal cells were isolated from syngeneic bone marrow immobilized in vitro on calcium phosphate surfaces with different structure, phasic, and elemental composition. After 45 days of subcutaneous ectopic osteogenesis in BALB/c mice, the tissues grown on these matrixes were characterized histologically. It was found that adhesion of bone marrow cells is the initial stage determining their future proliferation (conduction) over the artificial surface and the area of formed tissue plate. The success of histogenesis depends on surface roughness. The optimal roughness class was 4-5 (Russian State Standards), which enables differentiation of progenitor stromal cells under the specific microenvironmental conditions into the connective and adipose tissue cells. Differentiation of the progenitor cells into the stromal cells producing the hemopoiesis-inducing microenvironment also takes place in the foci of active hemopoiesis. Induction of osteogenic potential of the stromal precursors (osteoinduction) is determined by the ratio between calcium and phosphate atoms in surface coatings. In our experimental system, osteogenic differentiation of stromal mechanocytes was blocked only at Ca/P<0.5.

Animals↗
PubMed2004

In vitro regulation of cell behavior by calcium phosphates synthesized by the mechanochemical method.

Biological activity of eight hydroxyapatite powders synthesized by the mechanochemical method was studied in vitro. Introduction of copper and zinc atoms into synthetic hydroxyapatite structure promotes cell adhesion. Hydroxyapatites obtained by the mechanochemical method are promising base for a new class of materials and coatings with regulated bioactivity for orthopedics and traumatology.

Animals↗
PubMed2003

[Xenon effects on cells and receptors].

Xenon (Xe) is being more widely used in medicine owing to its unique physical-and-chemical properties of a noble gas. However, the knowledge about the physiological and patho-physiological changes occurring in the organism and in its separate structures during the interaction with Xe is still scanty. The aim of this survey was to briefly describe the presently known Xe biological-and-medical properties and certain mechanisms of Xe impact produced on cells and receptors as well as on the release of mediators and hormones. Besides, the Xe hemodynamic effects are also defined. The conclusion is that the Xe effect can be of a complex nature and can depend on the conditions of the body vital activity (optimal condition, activation, lesion), which predetermine, in their turn, the performance of the structural-and-functional units of various cellular systems.

Adrenal Glands↗
PubMed2002

Adhesion of Staphylococcus aureus to implants with different physicochemical characteristics.

Adhesion of pathogenic Staphylococcus aureus (strain 209) to BT1-0 titanium disks (12 mm in diameter) with different coatings and noncoated was studied in vitro by photocolorimetry. Transparency of bacterial suspension in normal saline was evaluated after 2-h culturing with the implants at 37 degrees C. The decrease of S. aureus content in the suspension due to its adsorption on implants was negligible and increased by 0.9-5.5% in comparison with the control (adhesion to glass). When the specimens were placed into bacterial suspension, the density of staphylococcal adsorption on the surface considerably increased (by 9-53%) in comparison with the control, which attested to active participation of the implants in bacterial adsorption. The degree of bacterial adhesion to the implants decreased in the following order: disk with calcium phosphate ceramic coating-disk with calcium phosphate X-ray amorphous coating-disk without coating-disk with cermet coating. The adhesion of Staphylococcus is a stochastic process depending on the sum of implant characteristics, in particular, on the phase composition of the coating, electric conductivity, and Ca/P ionic ratio. The authors conclude that the formation of antibacterial properties of coating by saturating them with antibiotics or impregnation with metals, specifically silver ion implantation, is justified, because it reduces the postimplantation infection risk.

Adsorption↗
PubMed2000

Activity of sympathoadrenal system and myelokaryocyte death during aging in AKR/JY mice.

Accelerated bone marrow cell death and activation of the sympathoadrenal system were observed during aging of highly leukemic 2-7-month-old AKR/JY mice compared to that in (CBA/CaLacxAKR/JY)F1 strain. Close correlation was revealed between activity of the sympathoadrenal system and necrotic and apoptotic forms of cell death. This can promote tumor process, because maximum changes in hemopoietic cells occur during advanced stage of the disease.

Adrenal Medulla↗
PubMed1997

[Results of studies of regulatory mechanisms of hematopoiesis in health and disease].

Local and distant hemopoietic regulatory mechanisms were studied under various emergencies (immobilization, cytostatic injection, radiation, etc.). There were common processes (cell migration, destruction, T-lymphocyte accumulation, activation of the microenvironment and hemopoietic precursors) forming the local basis for compensatory and adaptive reactions of bone marrow hemopoietic tissue. Emphasis is laid on the association of local mechanisms with the neuroendocrine system which inevitably becomes activated under extreme exposures. On exposure to irritants having no myeloinhibitory effect, neurotransmitters and hormones, mainly glucocorticoids and catecholamines cause the development of erythro- and granulocytopoietic hyperplasia due to stimulation of the hemopoiesis-inducing microenvironment (HIM). Under hemopoiesis-suppressing influences, catecholamine-induced activations of HIM's resistant elements is accompanied by simultaneous inhibition of hemopoietic cells and HIN's factors damaged by an irritant. Under these conditions hemopoietic separation caused by the heterogeneous effect of transmitters on the cell leads to imbalance of hemopoietic precursor proliferation and differentiation and, finally, to delayed hemopoietic tissue regeneration. At the same time, the neuroendocrine system does not seem to play a leading role as compared to the control intact hemopoiesis.

Antineoplastic Agents↗