Biomedical subjects

A V Karlov

Publications and source records attributed to A V Karlov.

16 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↗

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↗

PubMed2005

[Errors and complications of total endoprosthesis of the knee joint with the prostheses "Waldemar Link"].

The article presents results of an analysis of errors and complications for total endoprosthesing different pathological states of the knee joint with prostheses "Waldemar Link". The causes of early and late complications were found. The authors have developed original means for prevention and treatment of them. The most acceptable conclusion was the recommendation to observe the principles of active surgical strategy and using the means of complex conservative therapy at different periods of rehabilitation of the patients.

Adult↗

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↗

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↗

PubMed1999