[Effects of thymus tissue transplantation on the survival of mice exposed to a lethal X-Ray dose.]

During the radiation exposure of the body, processes similar to those characteristic of the natural aging of mammals occur. This phenomenon is most often referred to as accelerated aging. By transplanting the thymus tissue, it is possible to achieve a normalization of food and water consumption, a stabilization of weight gain, and a significant increase in the life expectancy of experimental animals, even after their lethal irradiation.

[Possible approaches to increase longevity of experimental animals.]

A statistically significant difference in the cumulative survival of Wistar rats born in different seasons has been shown: animals born in late November - early December had an average lifespan by 24,8% longer, a minimum lifespan by 14,3% longer, and a maximum lifespan by 20,7% longer in comparison with animals born in April. The geroprotective effect of the technique of thymus tissue transplantation into the immune privileged anterior chamber of the eye in animals born both in November and April has been shown.

Regeneration of jejunal wall defect using an implant based on silk fibroin fibers.

Regenerative properties of fibroin implant vitalized with allogeneic bone marrow cells were assessed. The study was performed using the experimental model of rat jejunum wall damage. Three weeks after surgery, we observed recovery of all layers of the jejunum wall at the site of injury and complete degradation of the implant material.

Effects of allogenic fetal pancreatic tissue transplantation on regeneration of islet cells in recipient rats with alloxan-induced diabetes mellitus.

The linear parameters and number of Langerhans islets were evaluated in rats with alloxaninduced diabetes mellitus after transplantation of fetal pancreatic tissue to the anterior chamber of the eye. The islets significantly increased in size by week 3 after surgery and a trend to an increase in their number was observed.

[Study of the accidental thymus involution during the formation of hierarchic communities by a novel physical method for recording the social stress].

A novel method for recording the aggressive behavior in newly formed hierarchic communities has been developed. A temporal and age-related dynamics of the accidental thymus involution in mammals has been studied.

[The increase of the average and maximum span of life by the allogenic thymic cells transplantation in the animals' anterior chamber of eye].

The effect of the allogenic thymic tissue transplantation in the immune-privileged anterior chamber of eye to the life expectancy of the recipient depending on its age was investigated. The thymic tissue transplantation from the young animals to the old ones leads to a significant increase in both the average and maximum life span of the recipient.

[Slowing down the rate of irreversible age-related atrophy of the thymus gland by atopic autotransplantation of its tissue, subjected to long-term cryoconservation].

An experimental procedure has been developed enabling to slow down the rate of irreversible atrophy of the thymus gland. The atopic autotransplantation of its tissue subjected to prolonged cryoconservation enables one to inhibit the aging of the organism with respect to several biochemical and immunological indicators.

[Atopically transplanted thymus tissues are capable of distantly changing the metabolic status of the body].

It has been found that the atopic transplantation of the thymus tissue from young animals in different variants is capable of significantly decreasing the rate of irreversible age-related atrophy of the thymus, which retards the age-dependent degradation of the T-cell unit of the immune system of the organism.

Tissue transplantation as a compensation for deleterious effects of ageing, radiation, diabetes, and craniocerebral trauma.

The presence of blood-brain and blood-ocular barriers allows the transplantation of various biological tissues into the brain and the anterior eye chamber without acute immune rejection. Tissue grafting into the immuno-privileged areas (brain, anterior eye chamber) allows its long-term functioning without immuno-suppression. This method was shown to be effective in compensating for the deleterious effects of ageing, radiation, diabetes, and craniocerebral trauma.

[RNA-synthesizing activity of brain chromatin in rats with experimental alloxan diabetes]. / RNK-sinteziruiushchaia sposobnost' khromatina mozgovoi tkani krys s éksperimental'nym alloksanovym diabetom.

Content of noradrenaline was decreased in neocortex and brain stem of rat brain by 70% and 50%, respectively, and that of serotonin--by 50% in the neocortex after development of the diabetic syndrome. At the same time, the RNA synthesizing ability of brain chromatin from the experimental animals was 3-fold higher as compared with controls. Catecholamines (L-DOPA, dopamine, noradrenaline) activated the RNA synthesis in controls by 40-50%, whereas in the animals with alloxane diabetes the effect was distinctly decreased. In vitro inhibitory effect of serotonin on the RNA synthesis was markedly decreased in preparations of brain chromatin from diabetic rats. Inhibitory effect of actinomycine D on the RNA synthesis was neutralized completely in controls after preincubation of the brain chromatin with L-DOPA, while only partial influence was detected in diabetic rats.

[Effect of catecholamines and serotonin on RNA-synthesizing activity in isolated nuclei and chromatin of the rat brain and liver]. / Vliianie katekholaminov i serotonina na RNK-sinteziruiushchuiu sposobnost' izolirovannykh iader i khromatina mozga i pecheni krys.

It has been shown that intraperitoneal injections of L-DOPA cause an increase in the matrix activity of chromatin and stimulate the incorporation of [3H]uridine into the nuclear fraction of rat brain cells by 35%. In vitro studies have shown that preincubation of brain chromatin with L-DOPA diminishes the inhibiting effect of actinomycin D on RNA synthesis. It has been found that the rate of RNA synthesis in vitro depends on concentrations of catecholamines (L-DOPA, dopamine, norepinephrine) and serotonin.

[Characteristics of the complex formation of L-DOPA with chromatin elements from brain cells]. / Kharakteristika kompleksoobrazovaniia L-DOFA s élementami khromatina kletok mozga.

It was found that L-DOPA interacts with brain cell chromatin. The life-time of the chromatin-L-DOPA complex is the greatest at 24 degrees C, while at 37 degrees C the destruction of the complex is observed. The specific binding is about 40% at pH 7.4-7.6. The Kd value calculated by the method of Scatchard is equal to 35.10(-9) M. Treatment of the chromatin-L-DOPA complex with DNAase I decreases the chromatin radioactivity by 15-20%. At the same time pronase treatment decreases the chromatin radioactivity by 80%. NaCl (0.2 and 0.4 M) causes the extraction of more than 70% of 3H-DOPA in the complex with chromatin proteins. Thus, L-DOPA interacts predominantly with chromatin proteins.

Serotonin and norepinephrine content in brain structures of rats with experimental and transplantation-compensated diabetes.

The development of alloxan-induced diabetes in rats is shown to be accompanied by a decrease in the norepinephrine (NE) and serotonin (5-OT) content in the neocortex and caudal segment of the brain stem. Simultaneously the intensity of 3H-leucine labelling of the brain tissue was decreased. The attempt to compensate the diabetic syndrome in rats by transplanting the embryonic pancreas (EP) into the anterior chamber of the eye (ACE) was successful. All the animals with the adapted transplant showed a return of the monoamine level to the normal, a decrease in urine glucose, as well as normalization of protein synthesis by the 14th-20th days.