THE EFFECT OF HIGH INTENSITY WHITE NOISE ON THE ULTRASTRUCTURE OF AXO-DENDRITIC SYNAPSES IN COLLICULUS INFERIOR OF ADULT MALE CATS. QUANTITATIVE ELECTRON MICROSCOPIC STUDY.

Environmental noise is a serious problem for the society and medicine. Chronic loud noise is known to produce numerous adverse effects on different levels of the organism. In addition to behavioral changes, the involvement of different regions of the brain was documented. The analysis of structural modifications provoked by noise in brain give the possibility to suggest that one of the effects of noise may be the alterations in neurotransmission. Therefore, of special interest should be the elucidation of the effects of chronic noise on the fine structure of synapses of brain areas participating in the processing of auditory information. In the present study, using transmission electron microscope. We elucidate the effects of high intensity chronic white noise on the morphology of axo-dendritic synapses, and size and diameter of synaptic vesicles in auditory region, inferior colliculus of adult male cats. Experimental animals were exposed to 100 dB (5-20 kHz) white noise for one hour per day, for 10 consecutive days. On 11th day, after special procedures, the area of interest was examined under electron microscope. In ~ 15% large synaptic terminals the clustering of synaptic vesicles, as well as swelling, partial vacuolization or degeneration of presynaptic mitochondria were detected. Morphometric analysis of docked (with presynaptic membrane) and undocked synaptic vesicle size revealed that docked vesicles are smaller than undocked vesicles. It was observed in both control and experimental animals, however, in experimental animals, such difference was more significant. Such results suggest that due to continuous transmission, the majority of vesicles are unable to replenish their cargo via transporters. Evaluation of synaptic vesicles size undertaken in the current electron microscopic study has advanced the understanding of the pathophysiology of white noise exposure on auditory brain processing regions, in addition to our understanding of fractional neurotransmitter release at the nerve terminal and on overall brain function.

FINE ARCHITECTURE OF THE HIPPOCAMPUS IN ADOLESCENT, ADULT AND AGED RATS. ELECTRON MICROSCOPIC STUDY.

The study included adolescents (P30-36), adult (P125-130) and aged (P330-340) male Wistar rats - 4 animals in each age group. The rats were housed individually, in wire-top polypropylene cages (30-cm width x 30 cm length x 25 cm height) and maintained on a 12-h light/dark cycle. Standard food pellets and tap water were ad libitum. The animal maintenance and electron microscopic procedures were conducted in accordance with European Union Directive on the protection of animals used for scientific research. The Ultrastructure of adult and adolescent rats are almost same. However, remarkable changes are expressed between adult and senescent rats. Precisely, in the last one there are following ultrastructural modifications - lipofuscin concentrations, small destructive cytoplasmic organelles, changes in presynaptic vesicular and mitochondrial quantity. Rare apoptotic signs in neurons. Analysis of all this means that aging in rat's hippocampus causes selective changes, also it underlines changes in neurotransmission and neuronal developmental pathways.

The monthly variations in mortality from the cardiovascular diseases in Tbilisi.

Results of the detailed statistical analysis of the monthly average decade mortality on the reasons for cardiovascular diseases in Tbilisi into 1980-1992 and 2012-2013 are represented. Variable +background and random component of time-series of mortality are determined. A share of the mean values of the component of variable +background from the mean value of real data of mortality constitute 68,4 % in 1980-1992 and 73,4 % in 2012-2013. Variations of the random component and their contribution to the real values of mortality (31,6 % in 1980-1992 and 26,6 % in 2012-2013) besides the air temperature can depend on many others meteorological, geophysical, social and so forth of factors. The scale of the six levels of cardiovascular mortality is proposed. In different months of year the indicated levels of mortality are various.

Periodontal diseases in patients with vitamin D-resistant rickets.

OBJECTIVE: To define the risk of development of periodontal diseases at vitamin D-resistant rickets. The material for the study was based on the data from 13 children of 0-18 years with vitamin D-resistant rickets (I group), 68 children with vitamin D-dependent rickets (II group), and the control group included 61 children of the same ages. The patients were divided into 3 age groups: I group of 0-5 years (deciduous/milk teeth occlusion), II group of 6-12 of years (mixed bite), III group of 13-18 years (permanent occlusion). For the qualitative data the differences between the groups were detected by using F criteria but for the quantitative data the differences between the groups were detected by Student's t test for independent selection. Mathematical processing was performed using statistical software SPSS-22. In all three groups the gingivitis of mild and moderate forms were fixed, among them acute course was revealed only in the group of vitamin D-resistant rickets. The rate of chronic, local, catarrhal and generalized gingivitis in the group of vitamin D-resistant rickets was reliably higher in comparison with both vitamin D-dependant rickets and control groups. In addition, a mild form of periodontitis with chronic course was revealed in all three groups the rate of which was reliably higher in the group of vitamin D-resistant rickets comparing with the ones of vitamin D-dependant rickets and control groups. CONCLUSION: the rate of inflammatory periodontal diseases in children with vitamin D-resistant rickets is higher than in children with vitamin D-dependent rickets and the control groups.

Validating the effect of muscle artifact suppression in localizing focal epilepsy.

Source localization of an epileptic seizure is becoming an important diagnostic tool in pre-surgical evaluation of epileptic patients. However, for localizing the epileptogenic zone precisely, the epileptic activity needs to be isolated from other activities that are not related to the epileptic source. In this study, we aim at an investigation of the effect of muscle artifact suppression by using a low-pass filter (LPF), independent component analysis (ICA), and a combination of ICA-LPF prior to source localization in focal epilepsy. These techniques were applied on the EEG data obtained from a left-temporal lobe epileptic patient by artificially contaminating the isolated spike interval, present in the four left-temporal electrodes, with a muscle artifact. The results show that the muscle artifact was fully suppressed. Applying the dipole and current-density reconstruction (CDR) source-analysis algorithms on the filtered data, we were able to identify the location of the epileptogenic zone similar to that of the original undistorted data.

Effect of chronic inhalation of toluene on behavior of rats of various age groups in multi-branched maze.

The effect of a 40-day toluene inhalation on learning of young and adult rats was examined in a multi-branched maze. Experimental rats of both age groups needed more time to pass the maze and made more errors than controls. This impairment was observed in young rats immediately after termination of toluene inhalation and in adult rats immediately and 90 days after toluene.

Effect of nadolol injected prior to CRH on stress-induced plasma corticosterone level in rat.

The proposed research is the part of our investigation of the role of catecholamines in the alterations provoked by stress. Especially, we elucidate if Nadolol injected prior to CRH ICV has some effect on plasma corticosterone level. 15 mg/kg of Nadolol (the dose sufficient to prevent CRH-induced increases in heart-rate for 2 hr), dissolved in saline was administered intraperitoneally, 30 minutes prior to CRH (The dose of interest for CRH - 1 mkg/kg - was determined earlier, as provoking the maximal increase of plasma corticosterone level after 20 minutes of its ICV injection). Whole blood was collected at 11.00 am, via indwelling jugular catheter at 0 (control) and 15 minutes after Nadolol injection, also 30 and 60 min after CRH injection. After centrifugation the plasma level of corticosterone was essayed using ELISA method. 15 minutes after Nadolol injection the level of plasma corticosterone in comparing with control wasn't changed, at subsequent time-points plasma corticosterone level was increased but significant difference was observed only after 30 minutes. Thus, according our results, 30 min after injection, the dose of Nadolol, sufficient to prevent CRH-induced increase in heart rate, doesn't preclude the CRH-induced increase of plasma corticosterone - one of key signs of the stress-axis activation. The results were discussed.

Stress-system: corticotropin-releasing hormone and catecholamines (review).

The brain's stress-handling system--the limbic-hypothalamic-pituitary-adrenal axis--is one of the most thoroughly studied circuitry of the central nervous system. As a result of stress-axis activation different behavioral and physical changes develop; these changes allow the organism to adapt. For this purpose stress-system closely "works" with other elements of central nervous system, which are involved in the regulation of emotion and structures, also with axes, responsible for reproduction, growth and immunity. Dysfunction of stress-system--it's hyper- or hypoactivity--is characteristic peculiarity of many pathological states and disorders. Various molecules (corticotropin-releasing hormone, vasopressin, glucocorticoids, mineralocorticoids, ACTH, its precursor proopiomelanocortin etc.) are engaged in the regulation of stress-axis. Among these molecules corticotropin-releasing hormone is supposed to have a key role in regulating the response to stress. Besides these molecules, the end-products of the stress-axis activation: catecholamines, different hormones and cytokines - control the activity of multiple levels of this axis. According some views catecholamines play one of the essential roles in the alterations provoked by stress-axis activation. In this review we cite some classical (Crousseau et al.) and modern data concerning corticotropin-releasing hormone and catecholamine activities during stress.

Effect of acoustic stimulation on GABAergic neurons in limbic structures of krushinskii-molodkina rats.

Quantitative study of GABAergic and main cells in the hippocampus and piriform cortex of Krushinskii-Molodkina rats was performed 1 month after the incidence of seizure activity evoked by acoustic stimulation. The number of neurons significantly decreased in both regions and, particularly, in the hippocampus and central area of the piriform cortex.

Pyramidal cell loss in hippocampus of young rats exposed to toluene.

In the present study the influences of toluene intoxication on quantity of the pyramidal and granular cells in hippocampus was analysed in young and adult rats. An inhalation route of intoxication was used in our experiments - animal inhaled toluene until attaining a sidewise laying position. This procedure was performed in the closed glass container, in which air was beforehand saturated with the toluene vapors. Experiments was carried out on two age groups (n=20): one and two months age rats. Inhalation period was 40 days, Each age group consisted of ten animals and was divided into the two subgroups: I - control animals (n=5), II - experimental animals (n=5). Assessment of the neurons' quantity in different structures was made according to the fractional approach method proposed by M. West. The results obtained showed that number of the pyramidal neurons decreases by 26% (I - 1067+/-83,8; II - 786+/-7; p<0,05) against the control in CA-3 field of the Subgroup II of the younger animals only. In the dentate fascia number of the granular cells does not change in either age group. Loss of pyramidal cells in the CA-3 field will induce deterioration of the hippocampal neural circuits and destroy of memory and learning processes in the rats.

Influence of toluene intoxication on the number of mitral and granular neurons in olfactory bulbs of rats.

In the last years, implementation of the volatile solvents in order to get a narcotic high, used via inhalation (sniffing), increased significantly, especially in the youth. Substances containing these agents induce hallucinations and euphoric state. In the present study the influences of toluene intoxication on quantity of the mitral and granular cells in olfactory bulbs was analyzed in young and adult rats. An inhalation route of intoxication was used in our experiments - animal inhaled toluene until attaining a sidewise laying position. This procedure was performed in the closed glass container, in which air was beforehand saturated with the toluene vapours. Experiments was carried out on two age groups (n=20 animals): one - and two months age rats. Inhalation period was 40 days. Each age group consisted of ten animals and was divided into the two subgroups: I - control animals (n=5), II - experimental animals (n=5). Assessment of the neurons' quantity in different structures was made according to the fractional approach method proposed by M. West (1999). The results obtained showed that number of mitral neurons in the olfactory bulb of the Subgroup II of the rats, sniffing since the age of one and two months, significantly decreased by 43% (p<0,05) and by 28% (p<0,01), respectively. Meanwhile, the granular cells remained unaltered in experimental animals of both age groups. Decrease of the projection mitral neurons, in its turn, results in disruption of the projections to olfactory cortex and hampers proper functioning of the olfactory analyzer.