[Ultrastructural characteristics of gap junctions in human glial brain tumors]. / Ul'trastrukturnaya identifikatsiya shchelevykh kontaktov v glial'nykh opukholyakh golovnogo mozga cheloveka.

AIM: to conduct an electron microscopic study of intercellular communication in the samples of gemistocytic astrocytoma, oligodendroglioma, and glioblastoma. MATERIAL AND METHODS: Surgically resected tumor tissue fragments were fixed in 2.5% glutaraldehyde solution, afterfixed in 1% OsO4 solution, dehydrated, and embedded in epoxy resin. Ultrathin sections were examined using a Jem 1011 electron microscope (Jeol, Japan). RESULTS: Solitary and closely spaced gap junctions (GJs) formed by the thin processes that have the ultrastructure of an astroglial processes were identified in the astrocytoma samples. In this case, chemical synapses were noted to be completely absent in gemistocytic astrocytoma and glioblastoma. The identified GJs had a small length and deformed nexuses. The oligodendroglioma samples exhibited intact astroglial processes around the chemical synapses; however, interglial GJs were not found. CONCLUSION: The investigation showed the presence of intercellular GJs with some ultrastructural differences in the samples of low- and high-grade astroglial tumors. According to current data, astrocytomic GJs are able to create a stable self-sustaining network that promotes tumor progression and provides resistance to a therapeutic intervention. At the same time, the noticeable reduction in the number of GJs, which is most pronounced in the oligodendroglioma sample, can accelerate tumor cell migration into the surrounding parenchyma. The investigation of GJs should be, of course, continued using a group of a larger number of glial tumors to confirm the intercellular communication features revealed in this study.

[PECULIARITIES OF THE STRUCTURAL ORGANIZATION OF VENTRAL POSTEROMEDIAL, VENTRAL POSTEROLATERAL, AND RETICULAR NUCLEI OF RAT THALAMUS (AN IMMUNOHISTOCHEMICAL STUDY)

The aim of this work was an immunohistochemical study of the expression of neuronal and glial proteins, and of gap junctions proteins (connexin 36, connexin 43) in ventral posteromedial (VPMN), ventral posterolateral (VPLN) and reticular (RТN) nuclei of the thalamus in rats. It was found that VPMN and VPLN of the thalamus were characterized by a homogeneous distribution of synaptophysin, grouped arrangement of astrocytes, horizontal orientation of somatostatincontaining myelinated and unmyelinated nerve fibers, forming the bundles, and running through the barreloid septum, expression of connexin 36 and 43 as well as of parvalbumin revealing barreloids in 4 µm-thick sections. In RTN the content of myelin basic protein, neurofilaments, parvalbumin, and somatostatin was increased, while the amount of glial fibrillary acidic protein and connexin 43 was moderate, and synaptophysin and connexin 36 were absent.

[Microbiota of lower urine tract and genital organs of healthy men and in infertility].

AIM: Study microflora of urine, ejaculate, urethra scrape in normal state and infertility. MATERIALS AND METHODS: 2 groups of men were examined: I (28)--control, conditionally healthy men (20 - 25 years of age), II (26)--infertile patients (25 - 35 years of age). Middle portion of morning urine, ejaculate, urethra scrape were studied in group I, in II--ejaculate. Bacteriologic study of urine and ejaculate was carried out in an extended kit of nutrient media (HiMedia) for facultative- anaerobic (FAB) and non-clostridia anaerobic bacteria (NAB). Urethra scrape and ejaculate were studied by PCR in group I. RESULTS: In urethra scrape and ejaculate a wide spectrum of FAB and NAB was detected in group I. Corynebacterium spp. and coagulase-negative staphylococci (67.9% each) were the dominant cluster of FAB. Eubacterium spp.--in NAB. Bacteriologic study of ejaculate corresponded in PCR with similar results of dominating bacteria. Among FAB the same clusters dominated during bacteriologic study of ejaculate from group II patients, among NAB--Propionibacterium spp., Peptococcus spp. and Peptostreptococcus spp. Quantitative characteristics of ejaculate of group I and II differed insignificantly. CONCLUSION: The frequency of detection of certain genera of FAB and NAB was significantly higher in patients with infertility than in conditionally healthy men, however quantitative parameters of the isolated microorganisms practically did not differ between groups.

[Neuronal and glial antigen distribution in the columns of somatosensory cortex of rat brain (an immunohistochemical study)].

The aim of the study was to detect the neocortical columns in the S1 field on frontal sections of brain of albino rats using the method of immunohistochemistry and the antibodies against neuronal (synaptophysin, neurofilament) and gliocyte (glial fibrillary acidic protein--GFAP, myelin basic protein) proteins. The examination of the expression of the major neurospecific antigens revealed that on thin sections (4 micromin) a column could be identified due to accumulations of the astrocytes and neuronal processes--axons and dendrites. GFAP expression study also showed that cortical layer I usually contained multiple large astrocytes with branching processes, as well as numerous smaller processes with high intensity of expression. Synaptophysin content was high in all the layers of the cortex, but the most intense reaction was detected in the molecular layer, similarly with the intensity of GFAP reaction. The expression of myelin basic protein was detected in accordance with the radially extending myelinated processes of the neurons in the cortex.

[Analysis of spatial arrangement of gap junctions in respect to chemical synapses in the serial ultrathin sections of rat barrel cortex].

Electron microscopic investigation of gap junctions (GJ) on serial sections of rat barrel cortex has shown that GJ were in contact with one or both processes that formed chemical synapses, however, these connections could not traced in single sections. In the serial sections, it was possible to observe two GJ in the immediate proximity to one another, in a single field of vision, thus, each GJ was traced in two or three successive sections in a series. Considering the described variants of GJ arrangement in the cortex, it is suggested that GJ could be a structural basis for local synchronization of the bioelectrical activity not only at postsynaptic, but also at presynaptic level, and the formation of GJ occurs both before, and after the development of chemical synapses.

[Structural organization of the barrel cerebral cortex in rat (an immunohistochemical study)].

Immunohistochemical investigation of the regional distribution of neuronal and glial elements in the barrels of somatic cortex was carried out in rats (n=10). High level of synaptophysin protein expression was detected in the in barrel walls together with the accumulation of astroglial cells in their central areas. Ultrastructural investigation of chemical synapse structure showed the predominance of asymmetrical perforated axospinous contacts, presumably of excitatory type. The symmetric inhibitory synapses were more frequently located in the barrel walls in the areas of the denser neuronal perikarya distribution, as well as on the large dendritic processes. The number of vertically oriented myelinated axons within the barrels was found to be significantly greater than the number of the horizontally oriented interneuronal circuits.