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Aim to study non-specific immune response characteristics (serum cytokine profile) in rats after subcutaneous implantation of the decellularized esophagus matrix. Methods Data were obtained in Wistar rats. The rats underwent subcutaneous implantation of decellularized esophagus (DE) and native allogeneic esophagus (NE). Explantation of sampling were carried out on the 7th, 14th and 21st day of the experiment. Explanted NEs and DEs were processed for histologic examination. The content of IL1α, IL2, IL4, IL17А, TNFα, IFNγ and GM-CSF in serum samples were tested by ELISA. Results In rat serum with DEs on the 7th day of the experiment it was significant increase in IL1α level in comparison with control group, IL2, TNFα, IL4 levels did not differ from the control group levels that indicates the stabilization of inflammation. The content of IL17A, IFNγ and GM-CSF significantly decreased compared to control. On the 14th day, IL17A concentration analysis showed a sharp decrease in comparison with the the 7th experimental day. We found decrease in IL1α level vs control group and decrease in IFNγ level vs 7th day. On the 21st experimental day was shown a significant decrease in the IL17A, IFNγ and IL1α content in DE rats. Conclusions It was found dynamic change in studied rat cytokine concentrations that correspond to favourable clinical picture in DE group in comparison with an active inflammatory reaction in NE group. IL1α, IL4, IL17A and IFNγ concentrations reflect positive dynamics of the wound healing process and the absence of local inflammation and rejection of decellularized matrices.

The tissue reaction of pig skin to implantation of decellularized and recellularized dermal matrices on a formed wound defect was evaluated by histological methods on days 2, 5, 8, 16, and 20 after surgery. Differences in tissue response to different matrices were identified. In experimental wounds coated with decellularized dermal matrices, we observed the formation of a scar tissue, which required autodermoplasty on day 12 of the experiment. In wounds coated with recellularized dermal matrices, all layers of the skin completely recovered by day 20 after surgery with the formation of full dermal and epidermal layers. Our findings suggest that reparative morphological changes in the wound depend on the presence of fibroblasts in the implanted dermal matrix.

Chronic renal failure (CRF) is one of the most challenging problems of contemporary medicine. Patients with chronic renal failure usually need renal replacement therapy as either hemodialysis, peritoneal dialysis or a kidney transplant. The latter is the most promising option for end-stage kidney disease. However, the shortage of donor organs, the complexity of their delivery, the difficulty in finding an immunologically compatible donor and the need for lifelong immunosuppression triggered advances in modern tissue engineering. In this field, the primary priority is focused on developing bioengineered scaffolds with subsequent recellularization with autologous cells. Using such constructs would allow for solving both ethical and immunological problems of transplantation. The aim of this pilot study was to develop a new method of renal decellularization using small laboratory animals. Materials and methods The study investigated the morphological structure of the obtained decellularized matrix and quantitatively tested DNA residues in the resulting scaffold. We proposed a new biophysical method for assessing the matrix quality using the EPR spectroscopy and conducted experiments on the matrix recellularization with mesenchymal multipotent stem cells to estimate cytotoxicity, cell viability and metabolic activity. Results The obtained decellularized renal matrix retained the native tissue architecture after a complete removal of the cell material, had no cytotoxic properties and supported cell adhesion and proliferation. Conclusion All the above suggests that the proposed decellularization protocol is a promising method to produce tissue-engineered kidney constructs with possible clinical application in the foreseeable future.

We modified the protocol of obtaining of biological scaffolds of rat lungs based on dynamic recording of specific resistivity of working detergent solution (conductometry) during perfusion decellularization. Termination of sodium deoxycholate exposure after attaining ionic equilibrium plateau did not impair the quality of decellularization and preserved structural matrix components, which was confirmed by morphological analysis and quantitative assay of residual DNA.

To reveal the changes in visual cortex structure following impaired early binocular experience, the size (somatic area) of callosal cells in areas 17, 18 ofmonocularly deprived and convergent strabismic cats was measured. Horseradish peroxidase was injected into the single ocular dominance columns of areas 17, 18 and the transition zone 17/18. In both groups of impaired cats the mean size of callosal cells in area 17 was increased in comparison to intact cats. In area 18, the similar difference was found in monocularly deprived cats only. It was shown that the differences in the mean sizes of cells are due to the increase of the number of large cells. In strabismic cats, the portion of large cells (soma200 mkm2) in area 17 was 58% and in area 18 was 8%. The relative share of large cells in areas 17 and 18 of monocularly deprived cats was similar (28 and 26 % correspondingly). These data show that early binocular vision impairments may lead to the changes in cytoarchitecture of cortical layers where the interhemispheric connections originate.

The size (somatic area) of 658 cells located in layers 2/3 of cortical areas 17, 18 of both hemispheres in intact monocularly deprived and bilateral strabismic cats was measured. These cells were retrogradely labelled after injections of horseradish peroxidase into ocular dominance columns in areas 17, 18. In all groups of cats, the mean somatic area of callosal cells was significantly larger than the mean somatic area of intrahemispheric cells. It was found that the mean somatic area of callosal cells was increased by 26.6% in monocularly deprived cats and by 20.2% in strabismic cats in relation to the mean somatic area of callosal cells in intact cats. In addition, the mean somatic area of intrahemispheric cells in monocularly deprived cats was indistinguishable from the mean somatic area of intrahemispheric cells in strabismic cats and in intact cats. It is concluded that early binocular vision impairments produce enlargement of callosal cells' size in the visual cortex.

We have investigated the neuronal connections of ocular dominance columns in the visual cortex of 5- 6-month-old divergent strabismic cats. Strabismus was induced by tenotomy of medial rectus muscle at the age of 13-16 postnatal days. The angle between visual axes of the eyes was assessed using photographic technique. It was found that severed ocular muscle partially reattaches to the eye globe. In some animals the deviated eye has returned to normal position, in the others the residual eye deviation was 5-15 degrees. The loss of cortical binocularity for such animals is well known [Sireteanu et al., 1993]. The differences in the length of cortical neuronal connections of ocular dominance columns were revealed between these groups of animals. In our opinion, in these animal groups different mechanisms are used to prevent diplopic vision and incongruence of two retinal images: one is alternating fixation and other--suppression of deviated eye activity.

We have investigated the interhemispheric connections of areas 17 and 18 in cats with impaired binocular vision (monocular deprivation, uni- and bilateral strabismus). Monosynaptic neuronal connections were studied using microionophoretic injections of horseradish peroxidase in the single cortical columns and analsys of spatial distribution of retrogradely labelled callosal cells was performed. In the cases of monocular deprivation and strabismus, the spatial asymmetry and eye-specificity of interhemispheric connections are retained. Quantitative changes of connections are more pronounced in strabismic cats. In cats with binocular vision impairments, as well as in control ones, the width of callosal-recipient zone is larger than of the callosal cells zone. This may indicate that interhemispheric connections are non-reciprocal in the areas of cortex that are more distant from the projection of vertical meridian of visual field. We expect that there should be morpho-functional in the cells that are providing connections in opposite directions.

We have investigated the developmental changes of intrahemispheric neuronal connections of the areas 1718 ocular dominance columns in monocularly deprived cats. Single cortical columns were microiontophoretically injected with horseradish peroxidase and 3D reconstruction of retrogradely labelled cells' region was done. Ocular dominance of injected columns and their coordinates in the visual field map were determined. In area 17 it was shown that for non-deprived eye the connections of columns that are driven via the crossed pathways were longer than connections of columns driven via uncrossed ones, and in both cases they were longer than connections in intact cats. The connections of deprived eye columns are significantly reduced. We have observed some changes in the spatial organization of long-range connections in area 17 for columns driven by the non-deprived eye (more rounded shape of regions of labeled cells, non-uniform distribution of cells within it). Maximal length of such connections did not exceed the length of connections in strabismic cats. We speculate that the length of cell axons providing for the horizontal connections of cortical columns has some intrinsic limit that does not depend on visual stimulation during the critical period of development.

The spatial distribution of neuronal connections in cortical area 17 in cats with bilateral convergent strabismus, surgically induced on postnatal days 10-14, was investigated. Single cortical columns of areas 17 and 18 were microiontophoretically injected with horseradish peroxidase and retrogradely labeled cells in both hemispheres were detected. The intrahemispheric connections in area 17 along the mediolateral direction (the projection of visual field horizontal meridian) were found to be either dilated or reduced. For most columns, the interhemispheric connections in this direction were increased, which may provide for more reliable unification of two visual hemifields. Moreover, the extension of intra- and interhemispheric connections in rostrocaudal direction (along the visual field vertical meridian projection) was detected in some cortical columns. Thus bilateral strabismus induced during the developmental critical period, modifies the structure of both of intra- and inter-hemispheric spatial neuronal connections of individual cortical columns in areas 17 and 18.

The interhemispheric connections of areas 17 and 18 of the cerebral cortex were investigated in cats with experimental unilateral strabismus. Single cortical columns were microiontophoretically injected with horseradish peroxidase, and retrogradelly labeled cells were demonstrated in the opposite brain hemisphere. After tracer injection in area 18 columns, the labeled callosal cells were located in area 17/18 transitional zone, similar to what was found in normal cats. However, in some cases the expansion of the region of callosally labeled cells distribution, was found. It is proposed that the extent of the region of callosally-connected cells may vary depending on whether the cells receive their input from intact or strabismic eye.

Microiontophoretic application of horseradish peroxidase to individual columns in fields 17 and 18 of the cat cortex was used to identify the distribution by area and layer of retrograde labeled cells in both fields. After application of marker to fields 17 or 18, the area of labeled cells in field 17 (in the tangential plane) was extended and orientated along the projection of the horizontal meridian of the field of vision. The area of labeled cells in field 18 in these cases was orientated along the projections of the vertical meridian. Similar differences in the organization of the connections of fields 17 and 18 were seen in the projection zone of the central 10 degrees of the field of vision at different elevations. Thus, the spatial distributions of internal and external connections in each field coincide and their orientations in fields 17 and 18 are mutually perpendicular. It is suggested that field 17 performs the more detailed analysis of information on the horizontal components of an image and communicates this to field 18, while field 18 is responsible for the more detailed analysis of information about the vertical components of the same image, communicating this to field 17.

Spatial distribution of horizontal intrinsic neuronal connections in area 17 of cat cerebral cortex was studied following HRP microion tophoretic injections into the single cortical columns. Cluster analysis of labelled cell distribution in superficial layers was performed in the tangential cortical plane. Area 17 was found to contain 7 +/- 1 clusters each consisting of 1-5 cells. Clusters were arranged in two rows, separated by a distance of 1.2 +/- 0.3 mm. The distance between the centers of the clusters that form the rows was equal to 0.8 +/- 0.3 mm. The spatial characteristics of cell clusters sending axons to cortical column, found in this study, were compared with the known data on the optical imaging of the activity of neurons of orientation and ocular dominance columns of visual cortex. It is suggested that area 17 cortical column receives inputs from cells of 6-8 hypercolumns that have similar ocular dominance and orientation preference.

Horseradish peroxidase (HRP) was injected microiontophoretically into nine single area 17 columns and six area 18 columns of the cat's cerebral cortex. Within the dorsal lateral geniculate nucleus most of the labelled cells were found in the laminae A. The ratio of HRP-labelled cells in lamina A to those in lamina Al (A/A1) was estimated. After injection of HRP in area 17 columns this ratio varied from 0.5 to 2.5, while after HRP injection into area 18 columns it varied from 0.2 to 0.9. These data may indicate that in the areas studied contain the columns that receive afferents from both ipsilateral and contralateral eyes.

Single cortical columns of areas 17, 18 in the cat were microiontophoretically injected with horseradish peroxidase. Spatial and laminar distributions of retrogradell labelled cells in both areas were investigated. Following injections in area 17 or in area 18 the labelled cells' region in area 17 was elongated (in a tangential plane) along the representation of visual field horizontal meridian. However the labelled cells' region in area 18 was elongated along the representation of vertical meridian. Such projection patterns appear to be common in these cortical areas throughout the central 10 degrees on various elevations (from -40 degrees to +10 degrees) of the visual field representation. Thus the spatial arrangement of intrinsic and extrinsic connections in each area coincides, at the same time in area 17 they are orthogonal to area 18. The following visual information exchange scheme may be suggested. Area 17 may supply the area 18 with more detailed information on the horizontal component of the visual image, and in the opposite direction the information on the vertical component of the same image may be supplied.

Spatial distribution of horizontal inner links in field 18 of cat cerebral cortex was studied after microiontophoretic administration of HRP into a certain cortical column. HRP labelled cell location and their distribution in plane of cortex surface and sagittal and frontal planes were detected. Ellipsoid shape and rostrocaudal direction of the area of labelled cells was demonstrated irrelevant to the column localization in field 18 (stereotaxic coordinates of the columns studied are from P4 to A14). Thus, topography of the field 18 inner links was coordinated with its macrotopography, detect established electrophysiologically.

Spatial contrast sensitivity was measured in kittens aged 6, 9, and 12 months and in adult cats. Cats had to open one of two small windows, which had a photograph of a grid, in order to obtain food reinforcement. The nonreinforced stimulus was a photograph of a uniform field of the same mean luminance. Visual acuity was constant in kittens aged 6 to 12 months. However, six-month-old kittens had low contrast sensitivity at low spatial frequencies (

The laminar structure of the cortical column connections in area 17 of the cat was studied using the microiontophoretic injection of the horseradish peroxidase. Following the enzyme injection in one column at different depths below the cortical surface the identification of morphological types of labelled neurons and the estimation of their localization were performed. When enzyme has been delivered in the whole depth of the column pyramidal neurons labelled were found in upper (I/III) and lower (V/VI) layers (ratio II;I). When the depth of enzyme injection exceeded the cortex width the cells in layer IV were labelled as well. The ratio between the quantity of cells labelled in upper and lower layers was preserved. (II; I). After the enzyme injection in the upper part of the column labelled cells were found mainly in the upper layers. It is concluded that the neurons of the column of have extensive (up to 5 mm), predominantly horizontal afferent connections with the cells in upper and lower layers while the connections with neurons in layer IV are local and do not extend beyond 0.5 mm.

Spatial distribution of intrinsic connections in the visual field centre projection zone of the cat striate cortex, was investigated. Retrogradely labelled cells formed an oblong area and were found in superficial as well as deep cortical layers. The labelled cells were located mostly medially to the column under study. The revealed asymmetry shows that the orientation column cells have more extended connections with cells representing the visual field periphery. We suppose that the "silent" regions are asymmetrically located in respect to the orientation column cells' receptive fields. This can account for the influence of the visual field periphery.

Special contrast sensitivity was estimated in kittens at the age of 6, 9 and 12 months as well as in adult cats. Acuteness of perception of grating pattern remained the same in kittens of 6 as well as 12 months of age. However, the former kittens were shown to have a decreased contrast sensitivity at lower spatial frequencies (cycles/degree). The contrast sensitivity reached the adult level at 12-month age. This seems to reflect a maturation of the higher cortical areas involved in the recognition process.

A study was made of the influence of moderate hypothermia on the mitotic activity of albino rat corneal epithelium. The animals were cooled by the contact method for one hour to 28 degrees C; such procedure was conducted at 6 a.m., at noon, and at 6 p.m.; the epithelial reaction to cooling proved to depend on the time, the greatest suppression of mitotic activity (14-fold) occurring at daytime 3 hours after the cooling. A tendency to normalization of cell division was observed 6 and 12 hours after the cooling. The number of mitoses decreased 3 hours after the evening cooling, no changes in the mitotic activity in 3 and 6 hours after the morning cooling; cell division was found to be suppressed in 12 hours.

Directional tuning of the striate cortex complex cells for motion of slit stimuli and visual noise field was investigated on unanesthetized cats. The investigated cells demonstrated different degree of orientational and directional sensitivity. Shifts of preferred direction for visual noise stimuli with respect to preferred direction for slit were found in orientational selective cells only. It is concluded that in spite of the fact that a visual noise field has no inherent orientation it activates orientational mechanism in the visual cortex.

Spatio-temporal interactions within complex receptive fields were investigated in the visual cortex of a cat by means of sequential presentation of two stationary stimuli. When two stimuli were presented in the phase (on-on or off-off) and sequential presentation corresponded to preferred movement direction, the response to second stimulus was enhanced (or less inhibited). When sequential presentation corresponded to opposite movement direction, the response was inhibited. Sequential presentation of two stimuli with opposite phase (on-off or off-on) in preferred direction inhibited the response to the second stimulus, but in nonpreferred direction the response was enhanced (or less inhibited). The strength of interactions depended on distance between stimuli presented in the receptive field and interstimulus time interval. It is concluded that direction selectivity is provided by asymmetry of spatio-temporal interactions between on-inputs and between off-inputs. Interactions between on- and off-inputs, which occur in case of multiedge stimulus movement may be used by the visual system for detecting an object from visual environment, for estimating object size and relative movement velocity.