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Connexin 43 (Cx43) is a multifunction protein that forms gap junction channels and hemichannels and is suggested to play an essential role in oxygen-glucose deprivation, induced via neuroinflammation during astrocytoma expansion into healthy tissue. To prove this assumption we studied connexin 43 localization and ultrastructure of gap junctions in samples of malignant brain tumor (anaplastic astrocytomas grade III). For confocal laser microscopy, vibratome sections of tumors fragments were incubated in a mixture of primary antibodies to connexin 43 and glial fibrillary acidic protein (GFAP), then in a mixture of secondary antibodies conjugated with a fluorescent label. After the immunofluorescence study, sections were washed in phosphate buffer, additionally postfixed with 1% OsO4 solution, dehydrated, and embedded in epoxy resin by a plane-parallel method. Ultrathin sections obtained from these samples were contrasted with uranyl acetate and lead citrate and viewed under a Jem 1011 electron microscope. Confocal laser examination detected a positive reaction to Cx43 in the form of point fluorescence. These points were of various sizes. Most of them were localized around or at the intersection of small processes containing GFAP. Electron microscopy of the tumor samples containing the most significant number of Cx43 revealed single and closely spaced gap junctions with a typical ultrastructure on the processes and bodies of tumor cells. Sequential analysis in the fields of view revealed 62 gap junctions in the area of 100 μm(2). Numerous gap junctions in anaplastic astrocytomas revealed in our study may indicate electrotonic and metabolic transmission between glioma cells, possibly promoting its progression.

BACKGROUND Current assessment methods of penile cavernous fibrosis in animal models have limitations due to the inability to provide complex and volume analysis of fibrotic alterations. OBJECTIVE The aim was to evaluate micro-computed tomography for assessment of cavernous fibrosis and compare it with histological, histochemical, immunohistochemical, and RT-PCR analysis. MATERIALS AND METHODS A controlled trial was performed involving 25 New Zealand male rabbits with induced testosterone deficiency by orchidectomy. Penile samples were obtained before and after 7, 14, 21, and 84 days from orchidectomy. We consistently performed (a) gray value analysis of corpora cavernosa 3D models reconstructed after micro-computed tomography, (b) morphometry of smooth muscles/connective tissue ratio, collagen type I/III ratio, and area of TGF-beta-1 expression in corpora cavernosa, and (c) RT-PCR of TGF-beta-1 expression. RESULTS Micro-computed tomography allowed visualization of penile structures at a resolution comparable to light microscopy. Gray values of corpora cavernosa decreased from 1673 (1512-1773) on the initial day to 1184 (1089-1232) on the 21st day (p

Astrocytes are the main glial cells maintaining water-electrolyte and energy balance in the brain. Today, astroglia is also believed to take a direct part in the regulation of synaptic transmission and in enabling synchronous operation of neurons at large distances. Astrocytes fulfil their functions through numerous processes that penetrate the entire neuropil. The authors believe that changes in the astrocyte membrane surface area per unit volume of neuropil directly reflect changes in the intensity of the astrocyte–neuron interaction. Strengthening or weakening of astrocyte regulation, undoubtedly, affect the functioning of neural circuits. Nevertheless, in spite of the growing popularity of research into the glia–neuron relations, this aspect remains insufficiently studied when it comes to the cerebral cortex. The purpose of this study was to layer-by-layer determine the astrocyte membrane surface per unit volume in the neuropil of the rat primary somatosensory cortex. The research was conducted on samples of the primary somatosensory cortex obtained from 5 white male rats (P60–80). After immune labeling against astrocytic marker S100B using the pre-embedding method, the samples were prepared for transmission electron microscopy according to the standard technique. In total, 250 electron micrographs were obtained for each layer of the primary somatosensory cortex, which were then used to determine the astrocyte membrane surface area per unit volume in the neuropil by means of the random secant method. The research found that this indicator is the minimum in the first and maximum in the fifth layers of the cortical column. In addition, the article discusses the possible functional consequences of uneven distribution of astrocytic membranes in the neocortex.

The phenomenon of unstable expression of gap junction's proteins connexins remains a "visiting card" of astrocytic tumors with various degrees of malignancy. At the same time, it stays unclear what is detected by the positive expression of connexins in astrocytic tumors: gap junctions, hemi-channels, or connexin proteins in cytosol. In the present work, for the first time, we demonstrate an ultrastructural evidence of gap junctions in pleomorphic xanthoastrocytoma, a rare primary brain tumor, the intercellular characteristics of which are poorly studied and remain very discursive and controversial. The primary tumor mass was resected during craniotomy from a 57-old patient diagnosed with pleomorphic xanthoastrocytoma Grade II based on the histopathological analysis. The immunohistochemical study was conducted with primary antibodies: Neurofilament, Myelin basic protein, Glial fibrillary acidic protein, and Synaptophysin. For electron microscopic examination fragments of tumor tissue were fixed in a glutaraldehyde, postfixed in a 1% OsO

Subjects of our experimental studies were neurons in the snail Helix Pomatia, from which continuous intracellular recordings according to our specific microelectrode recording technique were produced.

Autophagy in flower petal epidermal cells is a little studied process. However, it is of interest regarding the physiology of chlorophylless plant tissues. We show that the utilization of organelles in the Petunia hybrida L. flower petal epidermis occurs via the autophagic-like organelle targeting into vacuole during the particular process of vacuole fragmentation and growth of secondary vacuoles (ATVF). It differs from macroautophagy (formation of autophagosome) and microautophagy. Peroxisomes were shown to be subjected to both macroautophagy (as single microbodies and their assemblies) and to ATVF when they are in complexes with mitochondria and chromoplasts. In addition, we have demonstrated that ATVF in flower petals is accompanied with the sequestration of the cytoplasmic sectors located between the neighboring cell wall ingrowths, the ultrastructure of which has been reported in the present work for the first time. It has been shown there are more numerous mitochondria, a more pronounced ATVF, and a thicker cytoplasmic layer in the blue tissues, possibly reflecting more intensive metabolic processes in them compared to white tissues. We assume that these differences may be of interest for the further studies and may be discussed including in terms of anthocyanin-dependent photochemical effects.

Results about the spindle-like activity peculiarities and the dendro-dendritic gap-junctions numbers in the infragranular and supragranular layers (modules) of the rat somatic cortex columns are presented. During simultaneous recording of extracellular field potentials from the cortical columns, the following was revealed: (i) the spindle-like activity was more synchronized inside one cortical column than in different columns; (ii) in most of the experiments (9 out of 10) an amplitude of the spindle waves was two times more in the supragranular layers than in the infragranular layers. During electron microscopy investigation of the experimental objects used in the electrophysiological study, it was shown that the number of the gap-junctions was more in the supragranular columnar layers as compared with the infragranular layers (4.15% and 2.84% out of the total number of chemical synapses and gap-junctions identified in each module, respectively). The results obtained are discussed as possible structural base of the local electrotonic synchronization of the neuronal activity inside a cortical column.