Novel silver/poly-1-vinyl-1,2,4-triazole nanocomposite materials—possessing antimicrobial activity against Gram-positive and Gram-negative bacteria—have been synthesized and characterized in the solid state and aqueous solution by complex of modern physical-chemical and biologic methods. TEM-monitoring has revealed the main stages of microbial cell (E. coli) destruction by novel nanocomposite. The concept of direct polarized destruction of microbes by nanosilver proposed by the authors allows the relationship between physicochemical and antimicrobial properties of novel nanocomposites. At the same time, it was shown that the nanocomposite was nontoxic to the fibroblast cell culture. Thus, the synthesized nanocomposite combining antibacterial activity against Gram-positive and Gram-negative bacteria as well as the absence of toxic effects on mammalian cells is a promising material for the development of catheters, coatings for medical devices.
We studied the effect of VEGF-A in experimental myocardial infarction on attraction of progenitor cells into the regeneration zone. The appearance of CD34(+)CD45(+) cells known as low-differentiated progenitor cells was observed in the damaged myocardial tissue in the presence of a considerable excess of VEGF-A. These cells can act as precursors of mesenchymal tissues depending on the direction of differentiation.
The relationship between vascular endothelium growth factor (VEGF) and cardiomyocyte oxidative phosphorylation level in experimental myocardial infarction, caused by diathermocoagulation of the periconical ventricular artery, was studied by immunofluorescent microscopy. Staining showed uneven distribution of cytochrome c in the mitochondria in the focus of myocardial infarction 2 h after the operation. After 24 h uneven staining of cardiomyocytes was found in the peri-infarction zone and no staining in the zone of myocardial infarction. This indicated a significant decrease in the level of redox enzymes. This picture persisted till day 14. Intraventricular injection of VEGF to animals led to a significant increase of the immunohistochemical reaction intensity, which reached the peak by day 7. The distribution of immunohistochemical reaction products under conditions of VEGF blocking was about the same as in spontaneous postinfarction reparative restitution. Our data indicated that increase of VEGF concentration in the myocardium maintained and stimulated oxidative phosphorylation in cardiomyocytes during the postinfarction period.
The reparative processes in the myocardium were studied during the postinfarction period after intracardiac injection of vascular endothelial growth factor. The cytoprotective and mitogenic effects of increased concentration of vascular endothelial growth factor on cardiomyocytes were revealed: viable muscle cells were present in the myocardial necrotic zone over 3 days, while cardiomyocytes in the periinfarction zone exhibited mitotic activity of within 7 days after infarction modeling. One of the main morphogenetic effects of high concentrations of vascular endothelial growth factor is stimulation of angiogenesis in all zones of the infarcted myocardium. On the other hand, injection of exogenous vascular endothelial growth factor stimulated collagen formation processes in the infarction zone (a 44% increase of the volume of collagen fibers) and formation of cardiosclerosis foci in neoangiogenesis zones in the intact myocardium, which is an unfavorable side effect of high concentrations of vascular endothelial growth factor.
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