Vol 143, No 2 (2013)

The ipsilateral cortical associative connections of different areas of primary somatic sensory (S1) and motor (M1) cortex were studied in 25 cats after local coagulation and infusion of horseradish peroxidase. It was shown, that the distribution of the associative fiber in M1 and S1 areas corresponded to the borders of somatotopic representation of different body parts. The fields within M1 (4y, 6ab) and S1 (1, 2, 3a, 3b) with different morpho-functional organization were not connected by the system of association fibers crossing the cytoarchitectonic borders of the above mentioned areas. Primary somatosensory (S1) and motor (M1) cortex had no reciprocal connections. Single fibers connected neighboring areas of M1 and S1.

The aim of the study was the estimation of structural and metabolic changes in the rat cerebellum Purkinje cells (PC) in the dynamics of subhepatic cholestasis. Histological, histochemical and electron microscopic methods were used. It was found that the cholestasis induced the progressive intensification of the structural and metabolic disturbances in the cerebellar PC reaching their maximum on days 10–20 and resulting in PC death and PC number reduction. In the cytoplasm of these cells the reduction of the activities of succinate dehydrogenase, NADH-diaphorase, glucose-6-dehydrogenase was recorded together with the decrease of RNA content and the activation of lactate dehydrogenase and acid phosphatase. The disturbances of PC at the ultrastructural level included the destruction of the nucleus and organelles (especially, of the mitochondria), associated with the increase of phagosome size and number, augmentation of relative free ribosome number, appearance of close contacts between mitichondria and cell nucleus and organelles. After 45–90 days in survived animals gradual normalization of PC structure and metabolism took place apparently as a result of spontaneous cholestasis elimination due to the development of new bile ducts.

The purpose of this paper was to examine the possibilities of engraftment, and to study the differentiation of the dissociated cells from the embryonic primordia of the spinal cord and the neocortex of Wistar rats, after their transplantation into the sciatic nerve of adult animals. The cell suspension obtained as a result of a dissociation of fragments of the cervical spinal cord and the anterior cerebral vesicle from rat fetuses at day 15 of development, was injected into the proximal segment of a previously damaged sciatic nerve. Using the immunocytochemichal marker of neural stem/progenitor cells (Msi-1) the transplanted cells were identified in the nerve trunks after 1 day after the operation. After 21 day some of these cells underwent differentiation into NeuN-immunopositive neurons, however their number was small. Thus, dissociated precursor cells from embryonic rat spinal cord and neocortex survive for three weeks under conditions of transplantation into the damaged nerve and retain the ability to differentiate into neurons, but the number is small. Most of the cells in the neocortex transplants, unlike those from spinal cord transplants, within 21 days after the operation were represented by the ependymocytes.

A quantitative study of follicle average cross-sectional diameter distribution was conducted in the thyroid gland (TG) of mouse like rodents (25 tundra voles, 24 CBA mice, 16 Wistar rats) after chronic exposure to low-level external γ-radiation both in the environment and under the experimental condition (absorbed dose range 0.05–0.5 Gy). Spectrum analysis of TG follicle cross-sectional diameter distribution in the irradiated animals has demonstrated a universal regularity: in comparison with the unirradiated animals there was a significant (1.3–1.7fold) increase in content of small follicles (with a cross-sectional diameter lower than 36–41 μm in the studied animal species). A similar phenomenon was reproduced in the model experiments (TG regeneration in rats after hemithyroidectomy). The observed activation of the folliculogenesis processes after chronic low-dose irradiation in small doses may be interpreted as a nonspecific adaptive reaction of TG to radiation induced damage of its parenchyma.

Visceral and parietal peritoneum was studied by electron microscopy in albino mice both in the process of ontogenesis and after its injury induced by the the intraperitoneal injection of 0.5% novocaine solution. It was shown that during the early stages of intrauterine development (Day 13) most of the mesotheliocytes and mesenchymal cells contained predominantly free ribosomes (polysomes) in their cytoplasm while other organelles were rare and were located near the nuclear envelope. Subsequently, the number of membranous organelles increased while that of polysomes decreased. One day after the injury of the mesothelium, undifferentiated mesotheliocytes containing numerous polysomes in their cytoplasm appeared at the margin of wound surface. In these cells the protrusion of membranes of nuclear envelope and their association with the membranous organelles (endoplasmic reticulum, Golgi complex, mitochondria) were detected. The observed interrelations between the nuclear envelope and the membranous cytoplasmic organelles is considered to be a possible way of their formation in the undifferentiated cells. Rare occurrence of this phenomenon in adults animals under the pathological condition and its absence during the physiological regeneration is considered as a manifestation of the law of histogenetic recapitulation.

Kidneys size and volume, absolute and relative mass, and tissue density was determined in 50 male and female nutria of different age groups (1 day, 2, 4, 5, 7.5 months and 1 year). It was found that in females the relative mass of the kidneys decreased with age, while in males this tendency remained only until the age of 7.5 months. In females from 1 day up to 1 year, the mass and the volume of the right kidney increased 11.44 and 11.25 times, its length and width — increased 2.16 and 2.59 times and its thickness — 2.07 times. In the left kidney, the corresponding indicators increased 11.69, 11.04, 2.14, 2.65 and 2.01 times. In males, from 1 day up to 1 year, the mass and the volume of the right kidney increases 19.49 and 16. 14 times, the length and the width increased 2.69 and 3.11 times and its thickness — 2.38 times. In the left kidney, the corresponding indicators increased 18.52, 16.83, 2.56, 2.98 and 2.72 times. The greatest increase in the indicators studied of the kidneys in female and male nutria took place from birth up to the age of 2 months. It was found that the density of the kidney tissue was the highest at 4.5 months. In the left and right kidneys in female nutria, its value varied from 1.09±0,03 to 1.12±0.02 g/cm 3 respectively, while in the males it changed from 1,04± 0.01 to 1.08±0.02 g/cm 3.

The role of serotonin in the nucleus raphe pallidus (NRP) development and the dynamics of its serotonin-producing neurons were studied during various time points of the postnatal period in normal Wistar rats and in animals developing prenatally under the conditions of serotonin deficiency. It was shown that NRP contained 2 populations of serotoninergic neurons with different morphological characteristics. At the initial stages of postnatal development (Day 5) serotonin-producing neurons included only large neurons, while the synthetic activity of small neurons appeared later (by Day 10). With age, under normal conditions, the size of large neurons and their number were increased which is indicative of continuing process of differentiation and/or functional load augmentation. The size and number of small neurons were practically unchanged with age. Serotonin deficiency during prenatal development lead to the disturbance of NRP structural organization. In comparison with the control animals, the size and the number of serotonin-producing neurons of both populations was decreased, their size remained unchanged with the age. Part of the neurons underwent degeneration, resulting in the reduction of their numbers. The damage observed may change the serotoninergic innervation of the medullary nuclei, responsible for the cardiorespiratory the control, thus causing the disturbances of cardio-vascular and respiratory systems.

The paper presents an analysis of authors’ results obtained using fixation of various tissues in zink-ethanol-formaldehyde (ZEF). It was found that fixation in ZEF, in comparison with other methods of fixation, allowed to achieve higher sensitivity of immunocytochemical reaction for a large number of antigens studied and, in many cases, to avoid heat unmasking of antigens. It also provided high resolution of the images obtained using the fluorescent and confocal laser microscopy. However, the studies of antigens with small molecular mass revealed the antigen diffusion from the site of original localization. The data obtained suggest that fixation of a material in ZEF fixative is promising for both immunocytochemical studies, including those using the fluorescent and confocal laser microscopy, and general histological practice.