The Effect of Structural Characteristics of Deproteinized Spongy Bone on Activity of Adipose Tissue Mesenchymal Stromal Cells.

We studied the effect of structural properties of deproteinized spongy bone (DSB) on functional activity of adipose tissue mesenchymal stromal cells of (MSC) for the potential use of these materials as components of a combined tissue-engineered construct. The porosity of the structure of DSB samples and the pore size promote MSC adhesion, migration, and proliferation on their surface and in the depth, revealing the architectonics of this bone matrix. The depth of cell penetration into the samples (from 273 to 702 µm) and an increase in the total number of cells (from 302 on day 1 to 1744 on day 7) demonstrated MSC adhesion, migration, and proliferation. The viability of cultured MSC was preserved for up to 7 days. The obtained results prove the possibility of using allogeneic DSB from femoral heads as a bone matrix in tissue-engineered constructs in combination with MSC. Such constructs can be used to efficiently restore the structural and functional integrity of the bone tissue in abnormal processes of various etiopathogenesis associated with the formation of bone defects or bone tissue deficiency.

Biological Response to a Novel Hybrid Polyoligomer: in vitro and in vivo Models.

The aim of the study is to evaluate biocompatibility of a novel hybrid polyoligomer in in vitro and in vivo models. MATERIALS AND METHODS: Cytotoxicity of the material was investigated using the MTT assay with human dermal fibroblasts as test cultures. To study direct interaction of the hybrid polyoligomer with cells, the fibroblasts were cultured on the polymer samples for 96 h, the cultures were assessed every 24 h using fluorescence microscopy. To study the tissue reaction in the area of contact with the donor bed and the morphological features of the implanted sample restructuring, a case-control study was performed using a rabbit model. Samples of hybrid polyoligomer were implanted into the bone defect formed in the left iliac crest in 10 rabbits. In the control group, the prepared allograft samples were transplanted into similar defects in 10 animals. The rabbits were sacrificed 4 and 8 weeks after the operation. The standard morphological methods with hematoxylin and eosin staining and immunohistochemical Ki-67 proliferation marker evaluation were used to assess the state of tissues in the defect area. RESULTS: The results demonstrate that the hybrid polyoligomer is not cytotoxic (cytotoxicity score 0-1), cells adhere well to its surface, retain their viability and typical morphology throughout the entire observation period. No negative impact of material implantation on the health state and behavior of animals was detected. Morphological examination showed the absence of inflammatory changes, formation of thin-walled capillary vessels, and considerable proliferative activity of mesenchymal cells in the defect area, even though it was more intense than in the control group. CONCLUSION: No inflammation signs were detected by 8th week of the experiment. It was defined that new bone was beginning to form. The results of analysis support the conclusion that the developed hybrid materials are prospective for further research as potential bone substitute.

Effects of erythrocyte microvesicles on the coagulation process stages.

We studied the effect of erythrocyte microvesicles on various stages of platelet-free autoplasma coagulation process. The erythrocyte microvesicles not only exhibited procoagulant activity, but also produced a pronounced anticoagulant effect by inhibiting fibrin formation process. The effects of microvesicles isolated from erythrocytes after 24- and 48-hour cell storage on plasma coagulation were different. The hemocoagulation effects of the "light" and "heavy" microvesicles were studied.

[Study of the relationship between shape and aggregation change in human erythrocytes].

The relationship between shape and spontaneous and fibrinogen-induced aggregation change in human erythrocytes was studied. Spontaneous and fibrinogen-induced erythrocyte aggregation was investigated using a rheoscope designed according to the method of H. Schmid-Schonbein et al. (1973). The erythrocyte shape was studied by means of light microscopy. It was shown that plasma enriched with lysophosphatidic acid and ATP depletion of erythrocytes led to the change of erythrocyte shape: discocytes transformed into echinocytes. It was found that spontaneous aggregation of such cells was considerably decreased. Aggregation of erythrocytes, treated with lysophosphatidic acid, was diminished more markedly. Fibrinogen-induced aggregation of echinocytes, obtained after treatment with lysophosphatidic acid and produced by ATP depletion, was also greatly reduced.

[Effect of fibrin monomer on spontaneous platelet aggregation].

Fibrin monomer (FM) was shown to cause a considerable increase in artificial shear-induced platelet aggregation. The aggregatory effect of FM was found to be tangibly higher than that in fibrinogen. The mechanism of action of FM on platelet aggregation is hypothesized.

[Role of lipid peroxidation in aggregation of blood cells in burn disease].

Spontaneous aggregation of erythrocytes and platelets was studied in burn injury. The plasma from burnt patients was ascertained to significantly increase blood cell aggregation in healthy individuals. It was shown that a-tocopherol-induced decreases in the rate of lipid peroxidation in plasma reduced its aggregatory activity to only a small extent. This suggests that antioxidant therapy is lowly effective in treating microcirculatory disorders in bum injury.