[Sources of nutrition and structural regeneration of articular cartilage].

Based on data obtained from comparative anatomic vessel material by methods of modern histology and cytology considerations were made on ways of structural and functional differentiation of chondrocytes and peculiarities of articular cartilage cytoarchitecture. Nutrition of articular cartilage cells is provided by subcartilaginous bone vessels. Synovial medium of the joint maintains the cartilaginous state of the surface of the connected skeletal units.

[The sources of osteogenic cells in endochondral osteogenesis].

In the cartilage anlagen of the femoral bone of albino rat fetuses, the appearance of a primary locus of endochondral substitution was observed. The cellular composition in the locus is represented mainly by endothelial and perivascular forms. It was confirmed by the methods of cytology, autoradiography and cytophotometry that the perivascular cells penetrating into the cartilage resorption lacunae together with blood-vascular capillaries appeared to be initial forms and a primary sources for the emergence of osteoblasts in the endochondral replacement zone.

[The cellular mechanisms of articular cartilage differentiation].

The ways of structural-functional differentiation of chondrocytes and the characteristics of cytoarchitectonics of the articular cartilage were considered. The trophism of cells of the articular cartilage is realized from bone underlying it. Towards the articular surface, the degradation and elimination of chondrocytes were found.

[The mononuclear and multinuclear cells of tissue resorption and their functional characteristics].

Mononuclear and multinuclear chondroclasts as well as osteoclasts and their involvement into the processes of replacement of provisional cartilaginous skeleton by definitive bony one were cytogenetically studied during ontogenesis of terrestrial vertebrates (amphibians, reptiles, birds, and mammals). It was detected that mononuclear and multinuclear clastic cells were distinctive morpho-functional forms. The former are capable to resorb only non-calcified hyaline cartilage, the latter are capable to resorb only calcified tissues (cartilage, bone).

[The characteristics of cell differentiation in chondrogenesis and osteogenesis].

Principles of differentiation of chondroplasts and osteoblasts in developing vertebrates were studied from the viewpoint of morphologic criteria and indexes of specific biosynthesis. Local conditions of histogenesis and intercellular interactions are the main factors of morphologic and functional differentiation of a cell.