Biomedical subjects

K M Svetikova

Publications and source records attributed to K M Svetikova.

At least 19 recordsLinked to original sources

PubMed1996

[The status of the gastric and duodenal mucosa, biopsied from those who worked in the cleanup of the aftermath of the accident at the Chernobyl Atomic Electric Power Station, in an organotypic tissue culture].

Biopsies of stomach and duodenum different regions mucosa obtained from patients with gastroduodenitis (liquidators of consequences of accident in Chernobyl nuclear station--LCA CNS-- and control patients) were studied cultured in vitro. The following are the differences found. Mononuclear cells, differentiating into macrophages were exposed from control biopsies. Mononuclear cells exposed from LCA CNS biopsies formed rosette-like accumulations after mitotic dividing on a distance from the explant. Part of cells within the rosettes acquired processes and formed syncytial structure.

Biopsy↗

PubMed1991

[Structural-functional changes in the peripheral nerves after administration of several drugs].

Structural and functional changes in the sciatic nerve induced by some drugs were studied using morphological and electrophysiological methods. It was stated that the application of this drug on the nerve causes different degenerating changes. Electrophysiological data, using the regeneration of action potential, proved the presence of structural changes in the nerve after application of mentioned drugs and showed partly preserved conduction of the nerve trunks.

Action Potentials↗

PubMed1991

[The structure and nature of the macrophages participating in Wallerian degeneration of nerve fibers].

The nervus ischiadicus in white noninbred rats has been damaged by various means and then light- and electron-microscopically the sources of origin of macrophages, participating in removal of decay products in the distal part of the nerve have been studied. There is a close correlation between the process of Wallerian degeneration and aseptic inflammation. In the area of decay of the myelinated nervous fibers 4 types of cells have been identified and characterized. Three of them are precursors of macrophages, participating in removal of the myelin decay products: mononuclear cells of hematogenic origin, perineural cells, endoneural fibroblasts. The dynamics of these cells transformation into macrophages and into "foam cells" has been followed. The fourth type--Schwann cells; they do not directly participate in removal of the myelin decay products. They do not die, but, separating from the segments of the disintegrated myelin, dedifferentiate, proliferate and form cords, into which regenerating axons then grow in. To understand the role of various macrophages in the destructive and reparative processes, which develop in the nerves, is very important not only for searching definitive approaches in treatment of posttraumatic demyelinated processes, but for comprehending the mechanisms of certain autoimmune demyelinating diseases.

Animals↗

PubMed1990

[Changes in neural conductors and their end organs in the muscles and skin after major procedures of one-stage lengthening of the extremity by the G.A. Ilizarov method].

The state of the tibial nerve, intramuscular nervous fasciculi and terminals in muscles and skin has been studied in the canine extremities at large one-stage elongations after G. A. Ilizarov. By means of neuromorphological methods it has been proved that during the distraction in the tibial nerve microscopical areas of overstrain of the nervous fibers are formed. This results in appearance of degenerative alterations both in the nerve itself and in the tissues, which it innervates. Together with the destructive processes, during all stages of distraction in the extremity, regeneration of nervous apparatuses took place. However, reparative processes were poorly manifested during those stages. Only after distraction is stopped (in 6 months--period of the extremity fixation) the regenerative processes predominate. It is possible to suppose that the manifestation degree of degenerative and reparative changes depends immediately on duration of distraction.

Animals↗

PubMed1989

[Effect of neurite-stimulating protein on the growth and proliferation of peripheral glia cells].

Proliferative activity of peripheral glia was investigated in the organotypic culture of peripheral nerves of 9-10-day old chick embryos. The neurite-stimulating protein, a stimulator of the neurite growth in the organotypic culture of spinal ganglia, being added to the culture media sharply increased the mitotic activity of glia: on the 3d day its level was 3.5 times higher as compared with the control one.

Animals↗

PubMed1987

[Changes in the skin epithelium and nerve elements of the rat sole with directed regeneration of the sciatic nerve].

The work has been performed on Wistar rats and non-inbred animals. Their ischiatic nerves have been dissected at the femoral superior third under nembutal narcosis. The end of the sectioned nerve are connected by a fragment of an aorta from rats of the same age. The state of nervous elements and dermal epithelium of the hind extremity sole in the animals is studied by means of general histological and neurohistological techniques. Mitotic activity of cells in the plantar epidermis, thickness as a whole and its separate layers are estimated, keratinization coefficient and correlation of thickness of separate sheaths in the whole layer are calculated. Use of the arterial vessels for connecting the end of the cut ischiatic nerve, trophic ulcers, that usually take place after the nerve section, do not develop. At early stages after the operation mitotic activity in the epidermis decreases by 70%, and the layer thickness--by 40%. Restoration of both indices proceeds slowly. As soon as the regenerating nerve fibers reach the distal part of the ischiatic nerve, the state of the epidermis improves: the mitotic activity differs from the normal by 20-30%, and thickness of the epithelium--by 28-30%. Coordination of thickness of separate layers in the epidermis is not nearly disturbed. It remains in the same state up to complete restoration of receptory structures in the rat plantar skin (during 9-9.5 months after the operation).

Animals↗

PubMed1986

[Development of methods of connecting severed nerve trunks to restore their integrity].

An experimental model of a seamless end-to-end joining of severed sciatic nerve (with gaps between the two ends 5-8 mm-wide) using an implanted arterial vessel was elaborated on random bred and inbred Wistar rats. Histological examination showed that nerve regeneration along the implanted arterial lumen was directly oriented and was not accompanied by neuroma formation which was always the case in the control. It took some nerve fibers 20 days to join the gap between the cut nerve ends. In 4 months myelination of regenerating fibers was observed in the blood vessel lumen, in 3 months the lumen was filled with bundles of myelinated fibers, and in 9 months the structure of the regenerating nerve was similar to that of the mature trunk observed in animals. The elaborated experimental model is to be employed in the studies of reparatory histogenesis in peripheral nervous tissues. The data obtained may be used in neurosurgery.

Animals↗

PubMed1986

[Morphofunctional restoration of a nerve trunk by filling the defect with a blood vessel].

Dynamics of morphologic and functional restoration of the nerve trunk and separate receptive skin formations have been investigated in white rats after a sutureless connection of the cut nerve by means of the implanted artery. For testing the reparative processes neurohistological and electrophysiological techniques have been used. In spite of a relatively early restoration of the integrity of the injured nerve and reaching the nervous fibers up to the skin, functional organization of the dermal sensory apparatus is observed only in a year after the operation.

Animals↗

PubMed1984

[Action of epidermal chalone on the vaginal epithelial cell proliferation in ovariectomized mice stimulated by 17 beta-estradiol].

It has been shown that the DNA synthesis inhibitory effect of chalone on the vaginal epithelium of ovariectomized mice administered epidermal chalone three times (8, 4 and 1 h before 17-beta-estradiol injection) is dependent on chalone injection made 1 h before hormone injection. The decrease in the number of DNA synthesizing cells induced by 3-fold injection of chalone during 2 days is linked with the reduction in the level of exogenous estrogen in ovariectomized mice rather than with the duration of epidermal chalone action.

Animals↗

PubMed1981

[Effect of epidermal chalone on vaginal epithelial cell proliferation stimulated by estradiol].

Non-inbred and hybrid mice, line C57Bl and CBA in diestrus stage were subjected to ovariectomy and in 4-6 weeks they were given subcutaneously 17-beta-oestradiol (1 or 0.1 mkg per one animal). One hour before the animals were sacrificed, they were given 3H-thymidine intraperitoneally. It has been stated that 15-20 h after the estrogen administration the amount of DNA-synthesizing cells in the vaginal epithelium of these animals is 25 times as great as that in the control animals--castrated mice. When the epidermal chalone is administered locally or intraperitoneally (5 mg per one mouse), 10 min after the hormone injection, there is no inhibiting effect of the chalone on the proliferative processes in the vaginal epithelium stimulated with estrogen. When a single intraperitoneal injection of the epidermal chalone is given (5 mg per one mouse) 1 h before, or when it is given three times (2 mg per one mouse) 8, 4 or 1 h before the hormone is injected, there is a definite inhibiting effect in the proliferative processes. Their degree depends on how long the chalone was in contact with the cells.

Animals↗

PubMed1978

[Tissue specific effect of lymphocytic chalone isolated from rat spleen].

Chalone-containing alcohol extract from the rat spleen consisting of 8--10 substances of protein nature, according to the data of the disk electrophoresis, possesses a selective property to inhibit the entrance of human transformed lymphocytes into the phase of DNA synthesis. Injection of lymphocytic chalones to the mice allotransplants of a donor's skin grafts, which differ from the recipient by a strong antigen, temporally delays the rejection of the transplanted graft. In mice-recipients, the thymus treated with lymphocytic chalone is characterized by the depletion of the cortical substance.

Animals↗

PubMed1978

[Proliferative processes in the epithelium of the autotransplant and surrounding skin of mice].

Proliferative processes were studied in epithelial cells of skin autografts and the surrounding skin in mice of CBA line. In the animals subjected to the operation but without cortisone injection (Fig. 1, a and Fig. 2, delta), a high proliferative activity in the skin epithelial cells surrounding the autograft was observed during the whole course of the experiment. In the cells of the autograft, the mitotic activity, after inhibition, restored quickly up to the original level, and in 10 days it sharply increased and did not differ from that in the epithelium of the surrounding skin. The amount of DNA-synthesising cells in the epithlium of the autograft at first remained at the original level, and then, after a short sharp rise, it decreased up to its level in the surrounding skin and then was changing nearly in the similar fashion with it. After repeated injection of cortisone both indices of proliferative activity (Fig 1, delta and Fig. 2, delta) in the epithlium of the autograft and of the surrounding skin gradually increased although slower than in the controls.

Animals↗

PubMed1977

[Proliferative processes in the epithelium of mouse skin allotransplants following cortisone administration].

Proliferative processes were studied in the epithelium of skin grafts from mice of strain CC57 Brown and that of the skin surrounding the grafts in mice of CBA strain. The chart (Fig 1) illustrates cortisone action on normalization of DNA synthesis in the epithelial cells of the allotransplant. Throughout the experiment in operated animals which received no cortisone (Fig. 2, a and 3, a) a high proliferative activity was observed in the recipient's skin epithelium while it was sharply decreased in the epithelium of the allograft. Repeated cortisone injections gave a reverse picture: inhibition of proliferative processes in the recipient's epithelium and their intensification in the epithelium of the allotransplant.

Animals↗

PubMed1975

[Influence of cortisone on the implantation of skin allotransplants].

Skin transplants of CC57 Brown mice to CBA mice different in strong antigens controlled by H-2 locus of histocompatibility were studied with special attention given to the division of epithelial cells. Five-day-long injecting of cortisone (single dose 2,5 mg) was performed in 2 variants of experiments: 2 days before or 3 days after operation. The mean day of rejection of the graft after injection of the hormone was prolonged from 6,9 to 17,8--19,8 days. Cortisone retarded development of the inflammatory reaction, formation of the granular tissue and decreased mitotic activity in the recipient's epithelium delaying its growth and thus the transplant elimination. Degenerative changes in the transplant tissues diminished, while the mitotic activity kept its sufficiently high level until rejection.

Animals↗

PubMed1974