We compared the effects of transplantation of fetal fibroblasts and fibroblast-like mesenchymal stem cells of the bone marrow on healing of deep burn wound in rats. It was found that transplantation of fetal fibroblasts and fibroblast-like mesenchymal stem cells on the burn surface reduces cell infiltration, promotes the formation of vessels and granulation tissue, which creates conditions for more rapid healing of the burn wounds.

Hearts of 52 pups were studied histochemically and electron-microscopically at various stages of total-body hypothermia. The dependence of the myocardiocyte metabolic alterations on the factors acting in the myocardium during different stages of hypothermia and during subsequent warming is shown. The vitality of the cooled heart is largely determined by retaining not only of its function, but by its anatomo-physiological links with the organism. The method of the profound hypothermia of the donor organism is, according to the authors, one of the ways to sustain the donor heart vitality before transplantation.

Quantitative changes of structural correlations of transplanted allogenic human kidneys were examined in the histological slides by means of computer micromorphometry. The measurements were performed in 663 transplants selected randomly which had been in the recipient's body from several hours till 14.5 years. As a result of the study, parameters of glomeruli, tubules, blood vessels and connective tissue in the overall mass of donor kidneys were established starting from the time before transplantation and 6 months, 1-1.5, 2-3, 4-5, 7-14.5 years after transplantation. A progressive increase of sclerotic changes in the transplant is confirmed and the hypotheses about their genesis are proposed.

The authors have studied the dynamics of variation of redox enzymes in the muscles of replanted extremity in 40 adult dogs, which endured replantation of long-ischemized (18-21 degrees C, 4-6 h) extremities. It was discovered that during the postoperative period of observation (45 days) in the muscles of the replanted extremity are preserved obvious degenerative and dystrophic changes and decrease of metabolic and rehabilitation reaction. On the basis of the obtained data the authors employed the effective pathogenetic therapy.

The morphological, histochemical, and morphometric studies of the skeletal muscle from a canine amputated limb failed to provide support for the views existing in the literature on various types of muscular fibres making up skeletal muscles. It was shown that in terms of the length of muscular fibers, there was only heterogeneity in activities displayed by the same enzymatic systems, which vanished with muscular abnormalities. Also, a significant difference was found in the responses of antagonistic muscles, which should be taken into account in the morphologic examination of biopsy specimens to establish whether the skeletal muscles are viable.

The authors have studied the dynamic changes of metabolic processes and the functional and the structural preservation of the muscles under the influence of heat ischemia (18-21 degrees C) on 29 amputated posterior extremities of 21 adult dogs of the both sexes. It has been shown that direct muscle excitability disappears 5 hours after the influence of heat ischemia, although after 6 hours of observation the values of the metabolic processes in the muscles made 35-40% of the basic level. The character of the changes in the muscle excitability gives an idea of the duration of action of heat ischemia and the preservation of vitality of the amputated extremity only up to the moment of its complete disappearance. The final irreversible ultrastructural lesions of the overwhelming majority of the myocytes appear during the period of 6 to 8 hours of action of heat ischemia.

Comparison of the results of morphological investigations of the internal organs of dogs and sheep with gamma-neutron radiation sources, implanted in the abdominal cavity, has shown that the correlation between a degree of severity and type of morphological changes in this case is similar to that of identical irradiation from an external source.

Comparative histoenzymatic, electron microscopic and histologic studies of kidney preservation without perfusion have shown that the pattern of precipitation of tetrazolium reaction products correlates with the degree of ultrastructural damage to the epithelium of renal tubules. A previously made suggestion on the possibility of using the tetrazolium reactions for estimating the degree of preservation of ischemized organs and tissues has been confirmed.

Morphological, immunological, and radiometric studies showed antigen adsorption on red blood cells to be a mandatory step in the development of immune response. A certain dynamics of antigen retention on the red blood cell surface was established. It was observed that at 4-7 days after antigen inoculation its fraction adsorbed on erythrocytes was markedly reduced which coincided with the period of clinical manifestation of the immune response. This was coupled with changes in the physico-chemical properties and structure of red blood cell membrane. The amount of the antigenic material transferred on the membranes of all erythrocyte mass exceeds considerably the total antigenic charge on lymphocytes. This phenomenon appears to prevent simultaneous entrance of all the antigenic mass into immunogenesis organs and in this way to regulate the intensity and time of development of immune response.

The possibility of maintenance of circulation and subsequent restoration of the function of the heart in the organism of the donor, after 10-minute arrest of circulation, for transplantation of the heart was investigated. Study of the hemodynamic, biochemical, metabolic, and structural changes in the myocardium after 2-hour mechanical massage without and with pharmacological protection of the myocardium (glucose--insulin--potassium, hydrocortisone, dipyridamole), without and with restoration of cardiac activity in the organism of the donor and the recipient after transplantation of the second heart by the method suggested by Moory et al. in artificially created left ventricular insufficiency showed that direct mechanical massage of the heart may be used for its short-term preservation in the donor organism.

The article discusses results of the morphological study of xenografts of the pig's valves fixed in 0.32% and 4% solution of formaldehyde which remained in the human heart during the period ranging from 21 months to several hours. In the xenovalves there occurred progressive destructive changes in their connective-tissue basis, which led to weakening of the mechanical strength and to rupture of the cusps. In the majority of cases, no morphological signs of immune or nonspecific inflammatory cellular reaction were observed. The authors hold that polycondensation of protein molecules occurring in the course of preservation under the effect of formaldehyde, and formation of "superstrong" structures at the expense of increased number of transversal connections between collagenous fibres not always could ensure sufficient mechanical strength of the cusps of the graft.