In Vivo and In Vitro Analysis of Toxicity of a Prospective Magnetic Resonance Contrast Agent Based on Arabinogalactan and Gadolinium Nanocomposite.

We studied the cytotoxic effect of gadolinium nanocomposite on cultured mouse fibroblasts 3T3-SV40 and histological changes in the liver tissue of albino rats after its administration. For in vitro experiment, gadolinium nanocomposite on the natural matrix of arabinogalactan (nGd-AG) was dissolved in DMEM nutrient medium to concentrations of 0.005, 0.02, 0.5, 2, and 5 mM. In in vivo experiment, a nGd-AG solution was orally administered to rats through a tube in a dose of 500 µg Gd/kg in 1 ml of 0.9% NaCl for 10 days. The pattern and degree of influence of the gadolinium nanocomposite on the studied cell culture depended on the concentration and duration of exposure. IC50 of nGd-AG determined after cell incubation for 24, 48, and 72 h were 616 µg/kg (3.9 mM), 302 µg/kg (1.9 mM), and 222 µg/kg (1.4 mM), respectively. Histological changes in the liver of white rats induced by exposure to nanocomposite attested to the development of a compensatory reaction of the organ.

Reproductive Function of Male Rats and Motor Activity of Their Offspring in Fire Emissions Modeling.

We studied the reproductive function of albino male rats after long-term exposure to wildfire smoke and the species-specific behavior of their sexually mature offspring. After the end of exposure, the mean number of spermatogonia and the relative number of Leydig cells in rat testes decreased and the index of spermatogenesis decreased. The offspring of exposed males mated with intact females demonstrated impaired cognitive abilities and disturbances of species-specific behavior. The severity of these changes depended on time interval between the end of the inhalation exposure and mating.

Experimental lead intoxication symptoms with hyperglycemia state.

In lead intoxication model, with hyperglycenia state, atherogenicity coefficient reached 1,45 (1,35-1,85), if compared to 1,30 (0,85-1,40) in white rats exposed to lead. Heart rate reached 421,00 (411,00-468,00) per minute vs, 385,50 (359,00-399,50) per minute in animals died with lead intoxication, shorter median interval between QRS-complexes up to 143,00 (128,00-146,00) ms vs, 160,00 (150,50-169,00) ms was seen in animals exposed to lead.

Expression of caspase-3 and bcl-2 proteins as an indicator of functional state of brain tissue in white rats exposed to argentumarabinogalactane.

The article presents results on experimental modelling an influence of silver nanoparticles incorporated into natural polymer arabinogalactane matrix on brain tissue of white outbred rats. The rats underwent parenteral injection of silver nanoparticles incorporated into polymer arabinogalactane matrix (dosage of 100 and 500 micrograms of silver per kg of the animal weight). The studies covered expression of 2 proteins participating in apoptosis process, in mitochondrial activation type - caspase-3 and protein bcl-2. During experiment, the groups examined demonstrated significant dose-dependent effect of bcl- 2 protein expression and increased number of caspase-3 expressed and non-expressed hyperchromic cells under exposure to argentumarabinogalactane - that indicates disorders of cellular structure and apoptosis development.

[Induction of apoptosis in neurons of white rats under exposure of nanobiocomposite based on ag (0) nanoparticles and arabinogalactan].

There are presented results of the immunohistochemical study of neural tissue of outbred albino rats exposed for 9 days to the influence of the silver nanobiocomposite consisted of silver nanoparticles encapsulated into a matrix of a natural polymer - arabinogalactan. The research of albino rats was performed in 2 stages: half of the rats in each groups were decapitated immediately after the exposure (early period) and the rest animals - 6 months after the end of exposure (remote period). The impact of the studied substance was proved to cause functional changes in cells of the nervous tissue. After the subacute administration of the nanobiocomposite - argentum-arabinogalactan (nano-Ag-AG) in cells of the nervous tissue of the brain of albino rats the expression of apoptotic and anti-apoptotic protein (caspase-3 and bcl-2) was established to be changed. The number of normal neurons producing protein caspase-3 sharply increases. Herewith the number of immunonegative neurons fairly declines. Along with this there is noted the high level of bcl-2 content, one function ofwhich is the preclusion ofapoptosis. In preparations there is revealed a significant gain in the number of bcl-2 expressing neurons, however, the protective effect of the protein is not fully realized, that leads to the significantly increase in the content of damaged hyperchromatic cells. The evaluation of results of the immunohistochemical study of the nervous tissue of albino rats according to data concerning the proteins caspase-3 and bcl-2 expression permits to make a conclusion about the capability of nanoargentum encapsulated into polymer matrix by passing the blood-brain barrier to induce the triggering apoptosis cascade in neurons of the cerebral cortex.

[Evaluation of biologic effects caused by nano-silver influence on brain tissue of experimental animals].

The article presents results of histologic and immunohistochemical examination of nerve tissue of outbred white rats subjected over 9 days to nanobiocomposite containing nanoparticles of silver and natural biopolymer arabinogalactane. Exposure to the studied chemical was proved to cause structural and functional changes in nervous tissue. Comparing results of structural study of nervous tissue with expression of proteins caspase-3 and bcl-2 proves ability of nanosilver incapsulated into polymer matrix to penetrate through blood-brain barrier and induce apoptosis in neurons of brain cortex.

[Alteration of white rats brain tissue inducted by assessment of silver nanocomposite incapsulated in polymer matrix].

The paper present experimental materials of intragastric administration of silver nanoparticles encapsulated in polymer matrix of arabinogalactan by white outbred male rats. Animals were injected "pure" arabinogalactan and colloid silver solution containing silver macroform separately for comparison. Research provided data about status of brain tissue at the impact of these substances on organism. Histological analysis revealed the presence of a pathological process, character and intensity of which varied depending on the type of injected material. Pathological process under the influence of silver-arabinogalactan characterized by appearance in brain tissue of perivascular edema and development of acute inflammation in formation of glial scars, swelling of vascular bundles in sum.

[Transabiotic factors in an aqueous environment (a review)]. / Transabioticheskie faktory v vodnoi srede (obzor).

Excretion of metabolites is a characteristic feature of any alive organism. A big group of these products--second metabolites--because of their variability, quantity and physico-biological activity have a special importance in aquatic environment. Exometabolites of some organisms become an important part of environment for the others. The authors discussed the origin and evolution of exometabolites from simple waste products to biologically active substances. Quantitative and qualitative aspects of metabolic excretion by organisms in water conditions are analysed. The data on composition, origin and biological function of some second metabolites of different groups of aquatic organisms are presented. The authors propose a classification of second metabolites according to their functional significance. The role of metabolites and decay products in the development of chemical information streams in hydrobiocoenosis is analysed. Metabolites (soluble organic substances) form a field of chemical information for biotic community. The most important functions of this field are communication and conditioning. The authors emphasize the importance of investigations of chemical bioinformation field in aquatic ecosystems.

[On-board equipment-based study of psycho-physiological and biochemical responses dynamics of operators during 135-day isolation in the "Mir" orbital station phantom]. / Issledovanie s pomoshchíu bortovoí apparatury dinamiki psikhofiziologicheskikh i biokhimicheskikh reaktsií obsleduemykh v usloviiakh 135-sutochnoí izoliatsii v makete orbital'noí stantsii "Mir".

There present the investigative findings of the dynamics of psycho-physiological and biomedical responses of the test subjects during simulated emergencies at different stages of adaptation to 135-day isolation in the Mir orbital station mock-up. Ehe main operating factor of an emergency was the 2-day sleep deprivation in combination with the continuous complex and intensive operator work which included the elements of the professional activity of the cosmonauts, among them the simulation of the regular and emergency docking of the spacecraft. By and large the observed physiological responses were characterized by moderate degree of manifestation, they were of functional character and were adequate for the investigated experimental conditions. The impaired quality of performing the applied psychophysiological tests and what is especially important the operations simulating the cosmonauts, professional activity in the extreme emergency conditions is noteworthy. Judging from some indicators the manifestation was dictated by the duration of operator isolation in the Mir orbital station mock-up and by the duration of a contingency simulation. In the degree of manifestation and in the time of development some changes in the state and working capacity of the operators were characterized by the individual differences.

Group dynamics and crew interaction during isolation.

The Homeostat test system was used to determine the interaction effectiveness of the chamber crew during isolation. The group had a complex and unique structure, reflected in the fact that all four subjects expressed considerable leadership activity. The course of the Homeostat task solution parameters testifies to the formation of an intergroup communicative net, which was not completed. This phenomenon was accompanied by emotional tension in the group. The individual contributions to the interaction were investigated. The crew represents a small group with a complex communicative structure. This was due to the presence of above normal leadership activity in all four crew members. The complex course of the leadership activity parameter and the presence of elements of group management allow us to label the crew as a complementary group, which is capable of coping with a wide range of tasks in problem situations. At the same time, the complex group structure caused a certain level of emotional tension in the group. This tension was drained to the outside world by conflicts with the project management. Subjects B and H played a positive role in the reduction of intergroup tension.

[Study of the antigenic structure of hepatitis B virus proteins. I. Synthesis of pre-S fragments of hepatitis B virus proteins and their immunogenicity]. / Izuchenie antigennoi struktury belkov virusa gepatitaa B. I. Sintez fragmentov pre-S belkov virusa gepatita B i izuchenie ikh immunogennosti.

Fragments of hepatitis B virus envelope proteins corresponding to the parts of the pre-S domain were synthesised and immobilized on the carriers with low own immunogenicity. The highest stimulation of the antibody production was observed for the antigens immobilized on microspherical carriers or gelatin modified by H-Gly-Tyr-OH. Among peptides used for immunization, pre-S fragment 134-144, conjugated with microspherical carrier, proved to be the most active.

[Psychophysiological selection: status and prospects]. / Psikhofiziologicheskii otbor: sostoianie i perspektivy.

The major stages in the development of psychophysiological selection of cosmonauts in the USSR are discussed. The psychophysiological selection was originally based on the data of psychoneurological expertise of the flight personnel and achievements of aviation psychology in the USSR. This was followed by the development of psychophysiological research, using instrumentation and simulation flights. Further complication of flight programs and participation of non-pilot cosmonauts (engineers, scientists) necessitated detailed study of personality properties and application of personality tests. At the present stage in the development of psychophysiological selection great importance is attached to the biorhythmological selection and methods for studying man's capabilities to control his own emotional, behavioral and autonomic reactions as well as environmental parameters. The review also discusses in detail methods of group selection and problems of rational selection of space crews.