Vol 134, No 6 (2008)

The neurons of the gyrus dentatus, hippocampal area CA1-2, and the cerebellar granular cells were examined to test the hypothesis of the possibility of the syncytial connections between neuron cell bodies in the adult individuals of higher vertebrates. As a result of electron microscopic studies, the dense disposition of these neurons was shown together with their incomplete glial coverage. These cells were shown to establish the contacts with their cell membranes and to form interneuronal tight and gap membrane junctions. In these contact regions, the membrane perforations were found and the formation of cytoplasmic interneuronal syncytial connections with all their typical ultrastructural signs. Such connections could be established between several contacting neurons forming the common functional cellular cluster. These investigation confirm the hypothesis that the cytoplasmic syncytial interneuronal connections were possible, in addition to chemical synaptic and contact electrical connections, not only in the tissue culture and in the autonomic nervous system during the early postnatal ontogenesis, but also in CNS of the adult vertebrates.

To characterize the structural remodeling of paleoamygdala during the early juvenile period, the studies were performed in 40 male and female Wistar rats on 21, 24, 28 and 31 postnatal days. Serial frontal brain sections stained with Nissl's cresyl violet were used to study the cytoarchitectonics of paleoamygdala (dorsomedial - Med, posterior medial - Mep and posterior cortical nuclei - Cop), as well as the dynamics of the formation of these structures, by means of the registration of planimetry characteristics, counting the number of neurons and glial cells, calculation of glial and apoptotic indexes. The results obtained suggest the heterochronism of the morphogenesis and gender-dependent differences in the differentiation of paleoamygdala structures. By day 21 (the beginning of early juvenile period), only Med appeared to be differentiated, while Mep became recognizable by day 24, and Cop acquired the characteristic cytoarchitec-tonics only by day 31 (the beginning of late juvenile period). Significant gender-associated structural differences were found in Med since day 28, and in Cop and Mep - on day 31.

Quantitative immunohistochemical investigation was undertaken to detect the peculiarities of the activation of the hypothalamic-hypophyseal-adrenocortical system at the level of its central unit - the adenohypophysis - in the growing organism under the conditions of chronic exposure to psycho-emotional stressors of varying intensities. Sprague-Dawley rats aged 30 days were exposed to either «mild» or «severe» chronic restraint stress for 5 hours during seven consecutive days. After the last exposure to stress, rats were decapitated, the endocrine glands (pituitary and adrenal glands) were removed, weighted, and embedded in paraffin; histological sections were stained with hematoxylin and eosin. Sections of hypophysis were also stained immunohistochemically using the monoclonal antibodies against adrenocorticotropic hormone (ACTH) and proliferating cell nuclear antigen (PCNA) with subsequent image analysis. The results of the study suggest that the stress-related hyperplasia of corticotropocytes in the hypophyseal pars distalis of the peripuberal rats was mainly associated with differentiation of the immature precursor cells of the hypophysis rather than with the increased cell proliferation

Моrphologic and morphometric characteristics of the grouped lymphoid nodules (Peyer's patches) and of the small intestine lamina propria were studied in rats at the 19 prenatal and 1, 7, 14, 21, 90 postnatal days. The development of these structures was found to be heterochronic and fragmentary. The development of the individual components of the mucosal immune system was interrelated. The integration of the afferent and efferent limbs of the mucosal immune system with the processes of digestion and absorption, is regarded as its adaptation to the peculiarities of postnatal development of mammals and as the property of the functional system, maintaining the homeostasis of the internal milieu of the organism.

The data on the presence of the kidney cells can contain neuroglial markers (nestin, vimentin, glial fibrillar acidic protein - GFAP) appeared unexpected and require a detailed investigation. Therefore, the purpose of the current study was to demonstrate the structures containing these proteins in the rat kidney by means of immunocytochemistry. Immunocytochemical staining was performed using the antimouse monoclonal and antirabbit polyclonal antibodies. It was demonstrated that the renal corpuscle contained both nestin- and vimentin-immunopositive cells (podocytes). Vimentin was also detected in the cells of parietal epithelium of the glomerular capsule, single cells of proximal and distal tubular epithelium, medullar tubular structures, and in the stromal cells. No GFAP-positive cells were detected in the kidney. Thus, the combination of nestin and vimentin was found to be typical for adult rat kidney podocytes. This suggests probable similarity of cytophysiological properties of podocytes and activated CNS astrocytes.

This investigation was aimed at the evaluation of the borders of individual variability of the human lumbar spine lordosis. 224 nuclear magnetic tomograms of persons of mature age were analyzed using morphometric, statistical methods, method of three-dimensional (3D) computer modeling and finite-element analysis. During the investigation, a hardware-software complex for morphometric research was created together with the new method of development of 3D computer models of the lumbar spine. The application of 3D modeling allowed to extend the knowledge of human spine biomechanics. Tensions and deformations were calculated in all lumbar vertebrae and intervertebral disks on the basis of spine 3D models developed. Finite-element analysis proved that a normal angle of lumbar lordosis was optimal for the transmission of the adequate compression loads, while the extreme forms of individual variability (high degrees of hyper- and hypolordosis), by changing the geometry of the vertebral column, result in the decrease of the functionality of this system.

The purpose of the study was to detect the relation between the formation of ossification nucleus in the epiphysis and the ingrowth of vessels into it, using laser radiation of femoral heads. The study was performed in 30 golden hamsters, 20 of them starting at 10 days after birth were exposed to daily irradiation of the right hip joint(during 3-80 days). The left joint was used as control. The radiation was performed with «Agnis» laser device (radiation power - 2 mW, impulse frequency - 2500 Hz, exposure duration - 8 min, optical fiber diameter - 4 mm). Femoral bones of experimental and control animals were histologically studied at days 13 till 90. Laser radiation was found could delay vessel growth from diaphysis into epiphysis for up to 13 days, and the beginning of ossification nucleus formation in the femoral head - for up to 5 days. This suggests the direct relation of the development of bone ossification nucleus in the epiphysis and growing of vessels into its cartilage, since no other factors retarding the vessel growth and formation of bone nucleus were used.

The aim of the present study was to test the possibility of different antigens detection in the biological objects after their storage in methylsalicylate for two or more years before embedding in paraffin, using routine immunocytochemical methods. Using immunocytochemical reactions demostrating intermediate filaments nestin, vimentin, and GFAP, as well as neuronal markers NeuN, neuron-specific enolase, and doublecortin, as the examples, it was shown that long-term storage in methylsalicy-late does not prevent immunocytochemical detection of these antigens.

The authors suggest to distinguish the mesoaccumbocingulate dopaminergic system within the mesocorticolimbic dopaminergic system. It defines the formation of dependence on the influence of psychoactive drugs. The cortical center of the mesoaccumbocingulate dopaminergic system - anterior cingulate fields in rats (Сg1 and Cg3) - simultaneously represents the affective and motivation-mnestic center. The affective function of the rat anterior cingulate fields after the administration of psychoactive drugs, as well as the formation of dependence on them, is associated with the distribution of the dopaminergic endings of midbrain neurons in the nucleus accumbens and at the anterior cingulate fields, in particular, in the pregenual part.