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Biomedical subjects

T V Davydova

Publications and source records attributed to T V Davydova.

At least 19 recordsLinked to original sources

[Study of immunomodulating properties of beta-carotene in patients].

It was shown that in patients with hypertension, duodenal and gastric ulcers and erosive gastritis leukopenia and lymphopenia are seen. At the same time contents of T- and B-lymphocytes are decreased and contents of C- lymphocytes are increased in circulation blood. Peroral daily intake of 20 mg of beta-carotene during 3-4 weeks caused increasing the contents of B- and T-cells and decreasing contents of C-lymphocytes in blood of patients.

Adjuvants, Immunologic

[Effects of passive administration of serotonin and catecholamine antibodies on alcohol consumption of C57Bl/6 mice in experimental alcoholism].

The experiments on C57Bl/6 mice with natural ethanol motivation have shown that passive injection of anti-noradrenaline and particularly antiserotonin antibodies reduces several times alcohol consumption by animals. On the contrary the injection of anti-dopamine antibodies to affect voluntary alcohol consumption by mice have been found.

Alcohol Drinking

[Splenopentin--modulator of immunological and behavioral reactions in secondary immunodeficiency state induced by experimental alcoholism].

Effect of splenopentin on some patterns of immunity was studied in mice with chronic alcoholic intoxication. Splenopentin was administrated into animals once intraperitoneally (250 micrograms/kg). Administration of splenopentin was found to normalize several immunological patterns in animals with chronic alcoholic intoxication: the immune response to the thymus-dependent antigen sheep red blood cells and phagocytic activity of peritoneal macrophages. Also observations over C57B1/6 mice characterized by high level of alcoholic motivation showed that alcohol consumption in mice decreased after administration of splenopentin at a dose of 250 micrograms/kg during two weeks.

Alcoholism

[Lysosome proteinases and protein turnover in the liver, spleen and thymus of rats undergoing antigenic stimulation and fasting].

Antigenic stimulation (AS) inhibited cathepsin A and D activation in the liver induced by fasting. AS after short-term fasting (4 days) induced the activation increase in the most of lysosomal proteinases by 20-80% in the spleen and thymus, while AS of animals, upon 6- and 8-day fasting depressed the activation of all the investigated lysosomal hydrolases (cathepsin A, B, C, D and arylsulphatases A and B) and decreased the total protein half-life. The revealed peculiarities in the lysosomal proteolytic system function and intensified protein turnover in lymphoid organs may reflect the general reaction of the organism, directed towards the maintenance of immunological homeostasis and, in particular, towards antibody production.

Animals

[Immuno-correcting activity of vitamin A in stress].

Experiments on CBA mice have shown that oral vitamin A administration prevents stress-induced immunological disorders: depression of antibody-forming cell production, decrease in natural killer cell activity and T-lymphocyte mitogenic response. Vitamin A also prevents the development of thymus atrophy, lymphopenia and depression of phagocytic activity of peritoneal macrophages.

Animals

[Antibodies to catecholamines and serotonin during alcoholic intoxication in animals with different predispositions to the development of experimental alcoholism].

Experiments on C57Bl/6, CBA and DBA/2 mice characterized by different preferences for ethanol have shown that during chronic administration of alcohol to animals with natural ethanol motivation (strain C57Bl/6) the level of antibodies to catecholamines and serotonin was increased on the 3rd month of ethanol intoxication, with the voluntary alcohol consumption in mice decreased by this time. On the contrary in mice rejecting alcohol (strains DBA/2, CBA) no antibodies to catecholamines and serotonin have been found.

Alcoholism

[Composition and synaptic organization of the internal plexiform layer of the sensory membrane of the eye in turtles].

Synaptic organization of the internal plexiform layer (IPL) of the retina has been studied electron microscopically in two aquatic and two land Chelonia species. Certain signs in common of the IPL structure have been revealed, they are similar with those in other Vertebrata, as well as common peculiarities inherent in Chelonia of all the four species studied. Any species-specific differences are not detected. In the land Chelonia, unlike the aquatic Chelonia, a relative content of the amacrinal cell synapses is higher in serial combinations. The ratio of the amacrinal cell synapses to all bipolar neurocyte synapses is within the limits 3.1-4.1.

Animals

[Axospinal synapses in the forebrain cortex of aquatic and terrestrial turtles].

An electron microscopical investigation of synaptic organization of the superficial plexiform layer of three forebrain cortical zones (hippocampal, dorsal and piriform) in two aquatic and two land Chelonia species has been performed. As demonstrate the data obtained and those from the literature, the main elements of the axo-spinal complexes (spines--synapses--neural terminals) possess both stability properties, contributing to structural firmness of the contacts and their reliability during activities, and plastisity ensuring the maintenance of dynamic equilibrium and a possibility for adequate rearrangements. Under normal conditions, the functional shifts in ultrastructure of the synaptic apparatuses are, possibly, so negligible that they cannot mask certain specific fractures of the synaptic organization of the neural centers. When comparing structures of the axo-spinal complexes in functionally dissimilar cortical zones, more constant, common for all species of Chelonia studied signs are definitely revealed. They characterize a certain level of the neural processes integration. There are signs more variable, evidently, ensuring adaptive rearrangements within limits of the given level of the interneuronal connections organization which can be considered as ecological and species-specific peculiarities.

Animals

[Contacts of the basal processes of the visual cone cells in the outer plexiform layer of the sensory membrane of the eyeball in turtles].

In two tortoise (Agrionemys horsfieldi Gray, Testudo graeca L.) and three turtle (Emys orbicularis L., Clemmys (Mauremys) caspica Gmel, Tryonix sinensis Wieg) species, contacts of basal processes (synaptic peduncles of the cone cells) have been studied electron microscopically. Their ultrastructure and peculiarities in organization of specialized junctions between each other and with other neural elements are described. The interreceptory contacts revealed are considered to be of one of the gap junction type responsible for electrotonic interactions in the nervous system. The basal processes are shown for the first time to possess an ability to form connections on the body and on the fine branches of the tubular type horizontal cells. It correlates with a view of some physiologists on a mediated interaction of photoreceptors via the horizontal neurons.

Animals

[Comparative study of the dendritic spines in the principle cortical zones of the turtle forebrain].

A comparative investigation of dendritic spines has been performed in three cortical regions (dorsal, pyriform and hippocampal) of the forebrain cortical plate in the tortoise and turtle by means of light and electron microscopy. There are differences both between various cortical zones and at various levels of dendrites (proximal, middle and distal) within the limits of one cortical formation. The dorsal cortex has a number of signs demonstrating its more complex formation in comparison with the hippocampal and pyriform cortex. A possibility on homologicity of this zone with some mammalia is supposed. Owing to the data obtained, three groups of signs can be defined in the spinal organization of the cortical zones studied: common for all four species investigated (perhaps they are connected with a certain evolutional level in the neural system development), ecologically specific, those make difference between the tortoise and the turtle, and species-specific.

Animals

Phylogenetic and ecological features of the structural organization of the forebrain cortical plate in Chelonia: 1. Neuronal composition and dendrite spines of the cortical zones in land and aquatic Chelonia.

A comparative study was made of cytoarchitectonics, neuronal composition and ultrastructural organization of the three basic cortical zones (hippocampal, dorsal and pyriform) of the forebrain of four members of Chelonia (two aquatic and two land species). The features under study fall into three major groups as follows: (1) common to all the Chelonia under investigation and possibly of the entire order; (2) ecologically specific, i.e. common to animals with similar ecology and different in animals with different ecology; (3) species-specific, i.e. differing in individual species. The common structural features of the forebrain cortical plate in Chelonia underlie the morphological substrate responsible for specific functions in different cortical zones. It is precisely with respect to the common features that the dorsomedial dorsal cortex exhibits a more complex neuronal and synaptic organization as compared with other cortical zones. This part of Chelonia cortex is assumed to be homologous to mammalian neocortex. The more plastic ecologically specific and species specific features appear to provide adaptive specializations within a particular level of the nervous system organization.

Animals

Phylogenetic and ecological properties of the structural organization of the cortical plate in the forebrain of Chelonia. 2. Axo-spinal synaptic complexes of the plexiform layer of the cortical zones in aquatic and land Chelonia.

An ultrastructural study is performed with a quantitative analysis of some parameters of the synaptic organization of the superficial plexiform layer of the three basic cortical zones (hippocampal, dorsal and pyriform) of the forebrain in two aquatic and two land Chelonia species. On the basis of our own and literature data it is inferred that all the basic elements of the axo-spino synaptic complexes (dendritic spines--active synaptic zones--nerve endings) exhibit both stability, ensuring the structural durability and reliability of the contacts' functioning, on the one hand, and plasticity responsible for homeostasis and adequate transformations, on the other. Normally, functional shifts in the fine structure of synaptic apparatus are presumably too slight to conceal the specific features of the nerve centres' synaptic organization. This made feasible a comparative study of the structure of the axo-spinal complexes in functionally dissimilar zones, which revealed the following three categories of characters: (1) stable, common of all the Chelonia species under study and characterizing a particular level of the integration of nervous processes, and (2) variable, ecologically-specific and (3) species-specific, ensuring adaptation changes within a given level of interneuronal organization. It has been revealed that ecological differences in the synaptic organization of the cortical zones in the aquatic and land Chelonia are most pronounced in the pyriform and hippocampal cortices, i.e. zones of exclusively and predominantly olfactory projections respectively, and are considerably less pronounced in the dorsal cortex, the zone of predominantly visual afferentation.

Animals

Correlation between the morpho-functional organization of some portions of the visual analyser of chelonia and their ecology: I. Normal morpho-functional characteristics of the optic nerve and the tectum opticum.

Several methods (light optic, electron microscope and electrophysiological) were used to study the optic nerve and the tectum opticum of water turtles (two species) and of land tortoises (two species). As the result of study of the two levels of the visual analyser in four species of Chelonia three groups of signs of the morpho-functional organization were distinguished: signs common for the Chelonia under study; ecologically specific signs--common for water turtles and species-specific traits which are--different in species of the same ecological group. Specific features of structural-functional organization of the visually directed behaviour in Chelonia at the neuronal populations level were shown to correlate with the ecological features to a greater degree than with the systematic position of the species.

Animals