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.

[DNAse-I inhibition by the chromatin proteins of the brain cells in rats]. / Ingibirovanie DNKazy-I belkami khromatina kletok golovnogo mozga krys.

The effect of protein extracted from nuclei of brain cells on the reaction of DNA-ethidium bromide complex interaction with DNAase I and Bac. subtilis nuclease was studied. The nuclei were isolated from the brain of Wistar male rats weighting 180-200 g. The fluorescence was recorded on a Hitachi MPF-44B spectrofluorimeter. Proteins extracted from the nuclei with 0.6 NaCl substantially inhibited the DNAase I but not Bac. subtilis nuclease activity. Other studied fractions of nuclei lacked the capacity for inhibiting DNAase I.

[Compensation in behavioral disorders in rats receiving 5,7-DHT neonatally and by transplantation of embryonic raphe nucleus tissue]. / Kompensatsiia narushenii povedeniia krys, neonatal'no poluchavshikh 5,7-DOT, putem transplantatsii émbrional'noi tkani iader shva.

In 62 male Wistar rats the influence was studied of the transplanted embryonal tissue of raphe nuclei (NR) on the mechanisms of compensation of disturbances of exploratory activity, sensory attention, learning and emotional reactivity induced by neonatal injection of 5,7-DHT. In histochemical studies by Falk-Hillarp method the presence of yellow fluorescence confirmed the specificity of transplanted 5-HT neurones. It is found that NR transplantation causes in animals after 3 months recovery of orienting reaction to sensory stimuli, reduces rats reactivity in the open field, restores the ability to discrimination of emotionally positive influence, disturbed by neonatal injection of 5,7-DHT. The obtained data show the possibility of compensation of behaviour disturbances caused by chronic deprivation of 5-HT system activity by transplantation in the neocortex parenchyma of the embryonal tissue, containing serotoninergic neurones.

[The level of noradrenaline and serotonin in mice differing in behavior]. / Uroven' noradrenalina i serotonina u myshei, razlichaiushchikhsia po povedeniiu.

Laboratory mice possessing Robertsonian translocation Rb (8, 17) 1IEM in their karyotype, reveal statistically significant ability for extrapolation of the direction of stimulus movement which disappears from animal's view. Inbred CBA mice with the same translocation are less capable, and CBA mice with normal karyotype are totally incapable of solving this task. Cortical noradrenaline levels in mice with Rb (8, 17) 1IEM were the lowest and brain stem levels the highest among the three groups investigated. Serotonin levels reveal no changes among these groups.

Behavioural, biochemical and histochemical effects of locus coeruleus transplantation in rats with neurotoxic lesions of the catecholaminergic system.

Exploratory activity in the open field and noradrenaline concentration in the neocortex and brain stem were investigated in intact rats (n = 10) and in the following groups of rats with early postnatal neurotoxic (6-hydroxydopamine) lesion of the catecholaminergic system: (i) rats with embryonal locus coeruleus grafts in the frontal neocortex (n = 5); (ii) rats with the same grafts in lateral ventricles (n = 4); (iii) a control group with intracortical hippocampal tissue grafts (n = 3); (iv) sham-operated rats (n = 3). Experiments were performed by four independent groups of investigators using a double-blind method. In sham-operated rats as well as in rats with hippocampal grafts, and with locus coeruleus grafts in the ventricles, both exploratory activity and noradrenaline content of the forebrain were significantly lowered. In the rats with intracortical locus coeruleus grafts the level of exploratory activity was much higher (almost as in intact controls). This improvement of exploratory behaviour correlated highly with increased noradrenaline concentration in the forebrain. In all animals with locus coeruleus in lateral ventricles a significant increase in noradrenaline level of the brain stem was present, but no change of exploratory behaviour was observed. The grafts with the 3-mm-thick slabs of the adjacent tissue were dissected from the brain and used for histological analysis. The presence of typical locus coeruleus cells was shown in neocortex of all animals which received the grafts of corresponding tissue. The data show the possibility of stable compensation of the forebrain noradrenaline level and exploratory behaviour by embryonic noradrenergic neurons grafted into the neocortex, but not into lateral ventricles.

[Mechanism of action of DNAse from the rat brain]. / Mekhanizm deistviia DNKazy golovnogo mozga krys.

The mechanism of action of exodeoxyribonuclease from rat brain predominantly localized in neuronal nuclei was studied. The enzyme which is highly specific towards one-chain DNA can effectively hydrolyze the two-chain DNA of plasmid pBR 322 "activated" by the disruption of the phosphodiester bond in one chain. A kinetic analysis of DNA hydrolysis with a tritium label evenly distributed along the DNA molecule and terminally labeled with phosphate revealed that the enzyme hydrolyzes polynucleotides from the 5'-to the 3'-end via a partially processive mechanism.

[Characterization of DNAse from rat brain]. / Kharakteristika DNKazy golovnogo mozga krys.

Using gel filtration and ion exchange chromatography, a DNAse specific to a single-stranded DNA was isolated from the soluble fraction of rat brain nuclear proteins. The nuclear nuclease corresponds to alkaline DNAse obtained earlier from the intact brain. The enzyme is a Mg2+- or Mn2+-dependent exodeoxyribonuclease and hydrolyzes at the same rates the ss-DNAse from rat brain, calf thymus, E. coli and poly (dA). The major products of hydrolysis are nucleoside-5'-monophosphates. A possible role of the enzyme in reparation of neuronal DNA is discussed.

Activity of nucleases in the rat brain during training with emotionally varying reinforcement.

Training of rats with emotionally positive and negative reinforcements leads to increase in activity of acid (pH of 5.0) and alkaline (pH of 8.0) nucleases in the neocortex, hippocampus, areas of the midbrain (including the hypothalamus, subthalamus, and thalamus), and caudal section of the brain stem. However, the dynamics of nuclease activation differ depending on the emotional type of reinforcement and level of trainability of the animals. When intensities of enzyme activity are compared in the structures investigated, maximal activation is found in the caudal section of the brain stem.

[Rat brain nuclease activity during learning with emotionally different reinforcement]. / Aktivnost' nukleaz golovnogo mozga krys pri obuchenii na émotsional'no razlichnom podkreplenii.

Acid and alkaline activity of nucleases of the rats trained with emotional positive or negative reinforcement was estimated in the neocortex, hippocampus, midbrain, and in caudal portions of the brain-stem, using native and denaturated DNA as a substrate. The results showed the total increase in nuclease activity during learning. Nevertheless the dynamics of enzyme activation was different depending on the emotional state of rats during learning. The most active enzyme was found in the caudal portion of the brain-stem.