Morphofunctional Changes in the Tibial and Peroneal Nerves in Shin Lengthening Using High Speed Daily Distraction Technique.

A sustained decrease in the M-response amplitudes of m. gastrocnemius and m. tibialis anterior was revealed during experimental orthopedic shin lengthening in dogs using Ilizarov external fixator with an automated drive (distraction 3 mm/day in 120 steps). Transverse contraction of intrafascicular content (by 13.2%), endoneural hypervascularization (by 28-95%), axonal degeneration and myelin decompactization, and destructive changes of no more than 5% fibers were detected in the tibial nerve. In the peroneal nerve, the contraction reached 17.3%. Endoneurium hypovascularization (by 12%), axonal degeneration and demyelinization, and destructive changes of more than 20% fibers were detected in 6 of 9 experiments.

[PECULIARITIES OF BONE TISSUE MORPHOGENESIS DURING SHIN LENGTHENING USING THE METHOD OF TRANSOSSEOUS DISTRACTION OSTEOSYNTHESIS WITH THE INCREASED DAILY RATE].

Histogenesis of bone tissue was studied in 25 adult mongrel dogs under conditions of automatic shin lengthening by the technique of transosseous distraction osteosynthesis with the daily rate of 3 mm in 120 repeats using the methods of light, scanning electron microscopy, electron probe microanalysis, immunohistochemistry and morphometry. During the distraction period, cellular heteromorphism and proliferative activity of the cells of connective tissue interlayer and periosteum were clearly detected in the interfragmental diastasis. In the post-distraction period, the reduction of cellular heteromorphism and the increase of the biosynthetic activity of the osteoblastic cells were observed while the provisional endosteal bone regenerate of normotrophic type with the signs of organotypic reorganization was formed. Intramembranous osteogenesis was noted at all the stages of the experiment. The organ-specific nature of the newly formed bone occured by 30 days after the apparatus removal. Bone tissue plasticity and the conditions of high-fractional distraction allow to increase the daily rate of leg lengthening up to 3 mm, as well as to provide the formation of weight-bearing bone part during 45 days, thereby reducing by 31% the duration of the period of fixator use for shin lengthening in comparison with that one adopted in classic technique with the daily rate not exceeding 1 mm.

Role of subchondral bone in the restoration of articular cartilage.

The role of subchondral bone in the restoration of the articular cartilage was determined in experiments on mongrel dogs subjected to gonarthrosis modeling followed by subchondral zone tunneling and introduction of bone marrow suspension into the canal. Light microscopy, computer histomorphometry, and electron probe microanalysis showed that stimulation of functional activity of chondrocytes was achieved via correction of homeostasis of the cartilage and subchondral bone and improvement of tissue trophic. Restoration of the microarchitecture of the subchondral bone and improving its vascularization after tunneling with the introduction of bone marrow suspension into the drill holes enhances chondrocyte metabolism and recovers their functionality.

[T-cells immunity in oral lichen planus pathogenesis].

In this review the modern ideas of the cell-like immune pathogenesis mechanism of Lichen planus)LP) are described. The special attention is paid to molecular diagnostics methods ( immunohistochemical and others). Communication of emergence of oral LP with infectious diseases is shown.

[Structural reorganization of the main joint components during the experimental modeling of osteoarthrosis with reduced blood supply].

The reactive changes in the knee synovium, articular cartilage, and subchondral bone during osteoarthrosis modeling were studied in dogs (n = 5). The results of histomorphometry, scanning electron microscopy, and electron probe microanalysis have demonstrated that the osteoarthrosis model used (femoral artery ligation and the knee immobilization) lead to marked synovitis, axonal atrophy and nerve fiber degeneration in subsynovial nerves, as well as synovial membrane hypovascularization. Subchondral bone vascularization was shown to deteriorate, while calcium content was reduced. Destructive changes were detected in the articular cartilage. Chondrocytes of the intermediate zone which were equidistant from vascular and synovial sources of supply appeared to be the most vulnerable. The changes described are the consequences of the disturbed interactions of the main joint components indicating the reduction of synthesis with a predominance of catabolic processes.

Experimental morphological study of the effects of subchondral tunnelization and bone marrow stimulation on articular cartilage regeneration.

The articular cartilage was studied under conditions of experimental osteoarthrosis with tunnelization of the subchondral zone and injection of autologous bone marrow into the channels. Histomorphological studies showed that tunnelization of the subchondral zone with injection of autologous bone marrow into the channels stimulated reparative regeneration of the chondral tissue by inhibiting destruction of the joints.