[Wound epithelialization in rats depending on the quantity and orientation of microautotransplants]. / Epitelizatsiia rany krys v zavisimosti ot kolichestva i orientatsii mikroautotransplantatov.

Patches of autoskin (0.5 x 1.0 mm) were grafted on a full-thickness rat back skin wound (5.4 cm2). As a result of "island" epithelialization from microautotransplants (MATR), the skin defect underwent repair. It is shown that the advance of the wound re-epithelialization did not depend on MATR number and their orientation in relation to the wound surface. The use of MATR allows to restore the skin defect with the plastic coefficient 1:100. This reduces the deficiency of donor skin at extensive burns.

[Skin microtransplantation in the surgery of burns (a clinico-experimental study)]. / Mikrotransplantatsiia kozhi v khirurgii ozhogov (kliniko-éksperimental'noe issledovanie).

On the basis of experimental and clinical investigations the authors have shown that extensive burns in patients with true deficiency of donor resources might be treated by the method of micro-transplantation of the skin which consists in plasty of the wounds by pieces of auto-skin of small size. The reduction of size of the skin pieces gives the enlargement of the total line of marginal epithelialization and great plasty coefficient as compared with traditional methods of surgical treatment.

Ability of microautotransplants to re-epithelialize deep and extensive skin injuries.

Experiments with rats of different ages have established the potential of microautotransplants (MATR) of skin (0.5-3.0 mm2 in size) to produce neoepidermis on fresh and granulating wounds. The MATR induced a 40-fold increased rate of closing of the wound surface. Contraction of the re-epithelialized wounds followed the same trend found for an open wound. The rate of contraction of re-epithelialized wounds depends on the age of the rat and the degree of maturity of the granulation tissue. The most extensive contraction was observed in young animals. Neoskin does not contain skin appendages, shows increased exfoliation of horn flakes from the neoepidermis surface and contains epitheloid cysts filled by a horny substance. The use of the MATR technique in the clinic also leads to wound re-epithelialization. Human neoskin histologically is similar to that of animals. These results suggest that the MATR technique is an alternative approach in the treatment of extensive skin burns.

[Micro-autotransplantation of the skin. Changes in size and morphology of neo-skin]. / Mikroautotransplantatsiia kozhi. Izmeneniia ploshchadi i morfologii neokozhi.

A new technique of wide wound skin epithelialization by free transplantation of autologous skin fragments 1 mm2 in size is demonstrated. The experiments were carried out on strainless rats of different age, 100 per cent epithelialization of wound 5 mm2 in grafting skin micro-autotransplantation (MATR) was observed. The primary effectiveness of wound closing square to MATR square was 1:20. However, as a result of wound contraction the effectiveness (on neo-epidermis square) was finally 1:15 in old rats. During histological analysis hyperplasia of the epidermis was marked and decreased gradually. Skin MATR method is considered as organ-typical culture in vivo.

[Effectiveness of the treatment of deep amd wide wounds by micro-autotransplantation of the skin]. / Effektivnost' lecheniia glubokikh i obshirnykh ran metodom mikroautotransplantatsii kozhi.

It's experimentally show na 40-fold expansion of deep and wide skin wound covering by microtransplantation. For all this it is determined that quantitative and qualitative parameters of neoskin didn't depend on skin microfragments concentration 0.5 X 1.0 mm. Besides, histological structure of neoepidermis was analogous to epidermis in situ, despite hyperplasia. The contraction feature of neoskin conformed to contraction of open wound.

[Changes in the reaction of rat bone tissue to hypokinesia after administration of hydroxymethyl aminopropylidene bisphosphonate]. / Izmenenie reaktsii kostnoi tkani krys na gipokineziiu pod vliianiem oksidimetilaminopropiliden bisfosfonata (AMOK).

During 35-day hypokinesia rat spongy bone in the tibia and vertebrae varied in two phases. The first phase (up to 15 days) was induced by a stress-reaction and the second phase by adaptation to hypokinesia. Under the influence of subcutaneous injections of hydroxydimethyl aminopropylidene biphosphonate (AMOK) at a dose of 0.01 mg/kg/day bone changes disappeared: throughout the study spongy bone mass remained as in controls. AMOK administration at a dose of 5 mg/kg/day 10 days prior to hypokinetic exposure did not eliminate its inhibitory effect although the initial bone mass was 1.5-2 times higher than in the controls. However at the adaptation phase (beginning with day 15) bone mass increased, reaching the baseline. This indicates a decline in bone sensitivity to muscle unloading. It is concluded that AMOK modifies bone responses to various hypokinetic factors.

[Reaction of osseous tissue and the osteoclast population in rats to biphosphonates and vitamin D3 under conditions of hypokinesia]. / Reaktsiia kostnoi tkani i populiatsii osteoklastov krys na bisfosfonaty i vitamin D3 v usloviiakh gipokinezii.

Oral administration of hydroxy-dimethyl aminopropylene biphosphonate (DMAP) at a dose of 0.5 mg/kg increased the volume density (mass) of trabecular bone in the tibial metaphysis of untreated rats and helped to maintain it at the normal level in hypokinetic rats. Oral administration of hydroxy-ethylidene biphosphonate (OEDP) at a dose of 20 mg/kg and vitamin 24,25(OH)2D3 at a dose of 1,25 micrograms did not induce any quantitative changes in bones of untreated or immobilized rats. The combined treatment with either biphosphonate and vitamin D3 exerted a similar effect as compared to that of biphosphonates used singly. During hypokinesia the total amount of osteoclasts declined. This effect was also seen in response to biphosphonates and vitamin D3. The two biphosphonates produced an opposite effect on the osteoclast population in untreated animals: it increased in response to OEDP and decreased in response to DMAP. In contrast to OEDP, low doses of DMAP can efficiently inhibit bone resorption upon various routes of its administration and can be viewed as a preventive and therapeutic drug in the case of osteoporosis.

[Effect of diphosphonates on bone tissue of the rat during hypokinesia]. / Deistvie difosfonatov na kostnuiu tkan' krys pri gipokinezii.

The diphosphonate effect on bones was studied in Wistar male rats weighing about 200 g. The rats were kept for 60 days in small-size cages where their motor activity was diminished. Every day the rats were given per os 0.3% solution of 1-hydroxy-ethylene-1,1-diphosphonate (HEDP) containing 9 mg/kg phosphorus. In the course of hypokinetic exposure the rats developed generalized osteoporosis. Histomorphometric measurements demonstrated that the drug did not prevent mineral losses from the tubular bones (humerus, femur). However, the drug led to a complete bone mass recovery in the pelvic and a partial recovery in the sternum. The drug also produced a preventive effect on the population of cells-precursors of osteogenesis the number of which decreases significantly during hypokinesia.

[Comparison of the bone tissue reaction of rats to clinostatic and head-down tilt hypokinesia]. / Sopostavlenie reaktsii kostnoi tkani u krys pri klino- i antiortostaticheskoi gipokinezii.

Examination of spongy bones of rats exposed to clino- and antiorthostatic hypokinesia showed that changes in bone mass, bone cells and their precursors were similar in both cases. The bone resorption-bone formation process remained balanced. However, bone responses clino- and antiorthostatic hypokinesia exhibited certain differences. Clinostatic hypokinesia produced greater osteoporosis in the femoral bone, whereas bone losses in the humerus, sternum and pelvis were identical. Antiorthostatic hypokinesia led to osteoporosis that was identical in every bone examined. In addition, clino- and antiorthostatic hypokinesia caused different reactions of stromal precursor cells, the latter model producing a greater effect on them. It is concluded that immobilization-induced skeletal disorders are associated with a decreased rate of bone histogenesis which proceeds at a lower level rather than with the stress-reaction.

[Effect of 24,25-dihydroxyvitamin D3 on precursor cells of osteogenesis in immobilized rats]. / Vliianie 24,25-dioksivitamina D3 na kletki-predshestvenniki osteogeneza krys v usloviiakh immobilizatsii.

The experiments were carried out on Wistar SPF rats that were immobilized for 35 days. By heterotopic marrow cell transplantation under the kidney capsule to the normal rats and by cloning these cells in vitro it was found that osteogenetic potentials were significantly inhibited and the amount of osteogenetic precursor cells was reduced. The addition of 24,25(OH)2D3 vitamin (at a dose of 1.25 micrograms per day) to the animal diet led to the normalization of the above parameters. It is assumed that immobilization-associated osteoporosis develops via, among other mechanisms, inhibition of histogenesis of stromal precursor cells. The beneficial role of vitamin D3 is actually the activation of histogenesis of these cells which results in the recovery of bone remodelling during immobilization.

[Mitotic activity and the nuclear volume of the epithelial cells of the rat cornea after a space flight on biosatellites]. / Mitoticheskaia aktivnost' i ob"em lader kletok épiteliia rogovitsy krys posle kosmicheskogo poleta na biosputnikakh.

On total preparations of the cornea of rats flown on Cosmos-936 and Cosmos-1129 the following parameters of the epithelial mitosis were studied: mitotic index, ratio of mitotic phases, number of abnormalities of cell division, and number of chromosome aberrations in anaphases. These parameters were considered to be indicators of physiological regeneration. The nuclear volume of cells of two inner epithelial layers was measured, using a modified karyometric technique that yielded representative data. The lack of significant changes in the above mitotic parameters can be attributed either to the absence of a strong stress-reaction of rats postflight or to the discrepancy between the time of animal sacrifice and the time of the maximum post-stressor inhibition of mitotic activity. This study revealed some data suggesting that in weightlessness the rate of cell division remained unaltered. The mean nuclear volumes of corneal epithelial cells changed significantly (P less than 0.01) at late examination stages (days 6 and 29). This may be associated with rearrangements in the regulatory systems of the animal body postflight. It cannot be ruled out that an increased cell activity measured with respect to the nuclear size correlates with the intraocular pressure.

[Mammalian cell culture reaction to the action of a constant magnetic field of 1000 and 3000 Oe intensity]. / Reaktsiia kul'tur kletok mlekopitaiuschchikh na vozdeistvie postoiannogo magnitnogo polia napriazhennost'iu 1000 i 3000 E.

The effect of a constant magnetic field of 1000 and 3000 oersted on mammalian cell cultures was examined. The effect of prolonged (12 days with three successive subcultures) and short-term intermittent action (repeated 6 times 60 min exposures with a 60 min interval) was studied. The magnetic effect was evaluated with respect to variations in the cell population density, mitotic activity and cytogenetic parameters. The experimental findings indicated that the magnetic fields of the above strength did not change significantly the rate of cell division and cell morphology neither did alter the genetic apparatus at the chromosomal level.