Reconstruction of Electric Discharge Patterns and Electrogenesis Mechanism in African Sharptooth Catfish Clarias gariepinus (Clariidae, Siluriformes).

Electrical discharges (EDs) in the African sharptooth catfish Clarias gariepinus were studied. Irregular monopolar EDs, lasting for 8-10 ms and longer, and more complex EDs, lasting for 20-50 ms and characterized by specific indentation of the discharge pattern, were recorded in pairs of individuals exhibiting both aggressive and defensive behavior. The pattern of long discharges was reconstructed by adding short EDs with different latencies and amplitudes. The conditions for the formation of long EDs with asynchronous activity of electromotor neurons and the possibility of coordinated operation of the electric generator and electroreceptor systems in catfish were considered, since an increase in the duration of EDs lowers the threshold of their perception.

Electrogenesis in Two African Upside-Down Catfishes, Synodontis sorex and S. batensoda (Mochokidae, Siluriformes).

Weak electric discharges generated by the two species of the African upside-down catfishes, Synodontis sorex and S. batensoda are described. In both species two types of discharges were recorded in the course of aggressive-defense interactions in the pairs of individuals: short simple biphasic and longer (duration >20 ms) discharges with more complex waveform. The discharges of the latter type seem to result from a temporal summation (with various latency) of simple discharges. It is suggested that formation of the long quasimonopolar discharges enhances the coincidence of frequency spectrum of the catfish discharges with maximum sensitivity range of their ampullary electroreceptors.

[Cytomorphometric study on the effect of smoking on tissues adjacent to dental implants]. / Vliianie kureniia na sostoianie tkanei, prilezhashchikh k dental'nym implantatam, po dannym tsitomorfometricheskogo issledovaniia.

The aim of the study was determination of the effectiveness of peri-implantation zone tissues control by means of cytomorphometry in cellular imprints obtained from the area of dental implantation on a model applying a comparison of the state of the tissues of the peri-implantation zone of smokers and non-smokers. MATERIAL AND METHODS: Cytomorphometry was used for tissue monitoring in implant-adjacent areas by the Index of Destruction (ID) and the Inflammatory-Destructive Index (IDI) in the group of smoking patients: 6 females and 9 males (41 implant) and in the group of non-smoking patients: 13 females and 14 males (97 implants). Follow-up terms in both groups from the moment of gingival former or provisional crown placement comprised 1, 5, 15, 25, 30, 60, 120, 180, 240, 720 days. Significant increase of ID within 25-120 days was revealed in smokers. The study of Inflammation-Distraction Indices revealed a statistically significant increase in the values in group of smokers at 5 to 60 days. The results of using of cytomorphometric method allow conclude that smoking is a pathogenic factor that exerts its influence through initiation and sustentation of an inflammatory process in the tissues adjacent to dental implants.

Rearrangement of the Prefrontal Cortex Neural Activity in Both Hemispheres during Learning.

Neuronal activity of both right and left hemispheres of the rat prefrontal brain cortex was recorded in the two-ring maze during animal learning to operate in response to signals. At the beginning of learning, pairwise comparison of neural activity that accompanied correct and incorrect choice of the right and left sides showed significant differences in the left hemisphere and the lack of differences in the right one. With increasing percentage of correct choices during a session of learning, the differences in neuronal responses appeared in the right hemispheres and were reduced in the left one. The opposite trends in rearrangement of the total impulse activity are believed to be related to different roles of hemispheres in the construction of the internal behavioral model.

Electric Organ Discharges of Cyphomyrus petherici (Mormyridae, Osteoglossiformes) from the White Nile Basin.

The waveform and some characteristics of the electric organ discharges have been studied in 11 individuals of Cyphomyrus petherici, the only representative of the genus in the Nilotic fauna. The discharge is characterized by three to five phases with a prevalence of the second phase in terms of the relative amplitude and a wide variability of the total duration of discharge (from 212 to 558 µs). The comparison of the discharges of the species under study with those in the congeneric species and representatives of the genus Pollimyrus (which previously encompassed C. petherici) demonstrates a general similarity of the C. petherici discharges with those of Cyphomyrus, but not Pollimyrus. This is in agreement with the correspondence of the discharge characteristics observed in other mormyrids to the phylogenetic position and taxonomic status of the species.

Sucrose-enriched diet during maturation increases ethanol preference in rats.

In the present study we used a diet enriched with 10% sucrose, which was consumed by adolescent animals of the experimental group for one month. We found that consumption of sweet food during sexual maturation affected alcohol preference, anxiety, and locomotor and exploratory activity in the adult rats. Our data show that easily available tasty food during adolescence probably impairs the reward system and serves as a trigger of future alcohol preference.

Electric discharges and electrogenesis peculiarity in two African upside-down catfishes, Synodontis caudovittatus and S. eupterus (Mochokidae, Siluriformes).

The paper reports spontaneous generation of weak electric discharges with an amplitude of 0.4-1.0 mV and a frequency of 3-9 min-1 by solitary Synodontis caudovittatus fish. When fish individuals were tested in pairs, their aggressive-defense interactions were associated with an increase in the amplitude of the discharges (up to 30-45 mV) compared to the discharges of individual fish, while the duration of the pulses increased up to 20-25 ms due to the prolongation of the second phase. In S. eupterus, electric activity was recorded only in the course of aggression-defense interactions, while spontaneous generation of discharges was not observed at all. The paper discusses the different aspects of electrocummunication between the catfish including the role of the reversion of polarity of the merged summated discharges with increased duration.

[RATIO OF PREFRONTAL CORTEX NEURAL ACTIVITY BOTH HEMISPHERES DURING TASK OF CHOICE IN THE TWO-RING MAZE].

Neural activity in two symmetrical areas of the prefrontal cortex left and right hemispheres of the rat brain (55 and 47 neurons, respectively) were recorded during the execution of behavioral tasks in the two-ring maze. Experiments were carried out in two different conditions - task with the key, when only appropriate side to signal was reinforced, and without a key, when any choice was reinforced. Differential neural activity was estimated - the level of difference in firing on the right and left choice. When the animal did not guided by external keys (two behavioral situations: trails in a behavior block without any keys or error trails in behavior block with key presentation) there was observed prevalence of differential activity in the left hemisphere. The prevalence in the right hemisphere was observed in the correct trials in behavior block with key presentation. Apparently this is evidence of the dynamics in the hemispheric balance, depending on the external and internal conditions and the special role of the right hemisphere in the mechanisms of learning and inclusion of external determinants of the adaptive behavior response.

[Dynamics of osteogenesis associated with inoculation of autologous stromal cells from rat adipose tissue (experimental-morphological study)].

Experiment was evaluated on 40 male Wistar rats. On the experimental model of mandible injury, bone autologous graft from tibia was placed on the surface of mandible (host bone). In the main experimental group, consisting of 20 animals, autologous rat adipose-derived stromal cells (ADSCs) were inoculated in space between autograph and host bones. ADSCs were not inoculated in the group of comparison. In experimental group with inoculated cells, the formation of a new fibroreticular bone structures in space between autograph and host bone was observed. These structures further underwent secondary reorganization and differentiation during the process of remodeling. As a result of the conducted study it was shown that in the experimental group by the day 180, statistically significant reduction of the area occupied by an immature fibroreticular bone took place. The reported phenomenon could be explained as a result of decline of the number of active cells in the population of inoculated ADSC, which is in consent with theory of limited cell division number due to telomeres shortening, described by Hayflick L. and Moorhead P.S. (1961).

[Dynamics of osteogenesis after inoculation of autogenic mesenchymal stem cells of adipose tissue].

Experiment was conducted on 40 rats of Wister line. On the artificially reproduced experimental model autogenic mesenchimal stem cells (MSC) of adipose tissue were inoculated in space between bone autograph of tibia and mandible. MSC wasn't inoculated in the comparison group. Formation of a new bone substance in space between an autograph and mandible bone was observed. It was clear that after 120 days (180 days), there was a statistically significant decline of the area occupied by an immature fibroreticular bone. Described phenomenon, presumably, could be explained as a result of decline of the number of active cells in the population of inoculated MSC according to phenomenon of limited number divisions of cells on telomeres, described by Hayflick L. and Moorhead P.S.

[Influence of calcium and phosphate ions on the adsorption rate of alkaline phosphatase and some of serum proteins on the hydroxyapatite].

Calcium ions accelerate selective adsorption of AP on HAP and phosphate ions inhibit it. Since the biological function of AP is in the synthesis of phosphate ions from organic phosphates, enzyme activity contributes to its adsorption on mineralized tissues HAP, which can be associated with the peculiarities of the action of the enzyme adsorbed compared with dissolved. Apparently, the selective adsorption of enzymes and signaling molecules in the extracellular matrix to produce the microenvironment necessary for cell differentiation and function of tissue. Sorbate composition determines the type of cell differentiation, which, in turn, determines the properties of the synthesized matrix. Thereby circuiting occurs a feedback loop, to maintain homeostasis of tissues. These results can be used to develop a biomimetic material for medicine as well as the fabrication of multilayer coatings with desired properties by means of controlled speed by selectively depositing colloidal particles (nanoparticles). In the case of anisotropic particles the layers it is possible to obtain particles not only one type, but also with their desired orientation in each layer of particles by creating localized sorbent binding sites.

[Two-ring maze for research behaviour of animals].

Animal behavior is studied using a two-ring maze in which the animal has to choose one of two paths, the same length and then self-returning to the starting compartment. All sections of the labyrinth: the starting chamber, signal space, arms and food compartment blocked by one-way doors. Time periods of passing different chambers reflect different aspects of behavior: level of motivation, attention, short-term and long-term memory, cognitive (make a decision) and emotion and etc. The analysis of these time parameters allows evaluate various behavioral components, depending on the impact on the animal. We suppose that this behavior model can be useful in various neurophysiology experiments.

[Influence of transplantation of autogenic mezenhymal stem cells from the fatty tissues on osseogenic process (experimental research)].

In experiments on 48 rats of line Wistar, divided at 2 groups (first--basic group and 2-d group--group of comparison) through the use of morphological method was researched influence of mesenchymal stem cells (MSC) inoculated in the area of autogenic bone graft from tibia fixed at the surface of the jaw. The animals of group of comparison didn't get MSC. Time frames of watching: 21, 60, 120 and 180 days, 6 rats on the point of experiment in either of the two of the group. Data of this research had shown the intensification of bone formation process in the basic group of experiment under the action of the inoculation of autogenic MSC from adipose tissue, and as consequence of it, in eventual, merge of bone formations in a single entity.

[Blocks neuron activity parietal cortex monkey brain, connected with achievement of intermediate goals of multistage behavior].

The single unit activity of the monkey parietal cortex was studied during the task of alternative spatial selection. Simultaneously activities of 6--10 neurons were recorded. It was revealed that tonic impulse activity of parietal cortex neurons forms blocks. The structure of blocks reflects the structure of behavioral task and related to the achievement of interim targets in performing of be- havioral task. Earlier the formation of similar blocks of tonic activity was shown for unit activity of putamen and prefrontal cortex. Thus the data obtained evidence in favor of that grouping of tonic activity is not an individual feature of some structures but has more general character most likely typical and for other brain areas. Generally it shows that nerve control of complex much component behavior is accomplished in segments by formation of separate blocks in neuronal activity. These blocks are related to individual groups of actions which in combination lead to a final goal--performance of behavioral task in a whole. Key words: unit activity, behavior, monkey, parietal cortex.

[The stimulation of reparative regeneration in the treatment of fractures of the extremities with the use of new biotechnologies].

The paper presents the results of a study of Russian and foreign authors on modern methods of stimulation of reparative regeneration of bone tissue. Highlight general principles for the construction and use of bioplastic materials. An attempt to classify the most famous of biomaterials based on their physico-chemical and biological properties, as well as identified trends in the further development of tissue engineering and its importance in traumatology and orthopedics.

[Dynamics of formation of bone tissue in rats under the influence of new xenotransplantat "Norian"].

In experiments on rats CD comparative studies have been carried out which is the effect of osteoplastic material NORIAN CRS, the rate of bone regeneration after mandibular dental implants (titanium screw) and the combined effect of these processes NORIAN CRS protein and protein (Emdogein). Functionality and maturity of the newly formed bone tissue was evaluated by histological and biochemical methods. The results suggest that the use of osteoplastic material NORIAN CRS is the 120 days leading to almost complete regeneration of bone tissue. It was also found that the combined use of NORIAN CRS and protein Emdogein impractical because adding Emdogein not accelerate bone regenerative process, but in the early postoperative period may cause an inflammatory reaction.