Cytoarchitectonics of the tracheobronchial lymph nodes in rats exposed to carbon disulfide

Cytoarchitectonics and rearrangement of cellular composition in functionally different zones of the rat tracheobronchial lymph nodes have been studied at a short effect of the industrial carbon disulfide vapour at a maximally admissible concentration (MAC) (1 mg/m3 and 10 mg/m3), as well as after the effect of MAC of carbon disulfide in the inhaled air for 4, 7, 14 days. The inhalation of the carbon disulfide vapours results in certain changes of the cytoarchitectonics of the lymph nodes studied in dependence on concentration and duration of the substance effect in the air inhaled. The effect of the MAC carbon disulfide, when the experiment lasts for 2 days, is accompanied with a decreased lymphocytopoiesis in all the structural components of the node and with a sharp intensification in the number of plasma cells of the medullary cords, that demonstrates local immunocytopoiesis. An opposite picture is noted, when carbon disulfide is applied in an elevated concentration (10 mg/m3)--plasmic reaction is sharply inhibited in the medullary cords, lymphocytopoiesis is noticeably increased, certain signs of allergic reaction are also seen. A prolonged effect of carbon disulfide vapours (up to 14 days) in MAC results in lymphocytopenia of the nodes, in increasing destructive processes and in decreasing cell proliferation. Differences in reaction of the structural components are revealed in the nodes studied at the toxic effect: in the cortical plateau and in the medullary cords suppression of the lymphocytopoietic activity is noted, and in the medullary cords--inhibition of immunocytopoiesis.     

Dynamic glycogen synthesis in the hepatocytes of different areas of the hepatic lobes in rats

Using image analyser Magiscan, a quantitative analysis of the total glycogen and of its two fractions was made in hepatocytes of portal and central zones of the liver lobule of rats after a 48 hour starvation and 15, 30, 60, 120 minutes after refeeding. Glycogen content was the lowest after a 48 hour starvation and only a few cells of the central zone contained a noticeable glycogen quantity. Glycogen synthesis initiation began 15 minutes after refeeding. Glycogen synthesis is characterized by a higher glycogen content in the portal zone of liver lobule, and further this difference was even more increased. Different changes were observed in the content of glycogen fractions in the process of glycogen resynthesis after starvation of rats.     

Synthesis of lipids in the thymus of irradiated rats

Changes in the synthesis of total lipids from 14C-glucose and 3H2O and in triacylglycerol concentration in the thymus of rats X-irradiated with a single dose of 14.35 or 6.0 Gy were investigated. Both lipid synthesis and TAG concentration were found to increase in the irradiated rat thymus.     

Cytoarchitectonics and neuronal organization of the sturgeon telencephalon

Anatomy, cytoarchitecture and neuronal composition of the i everted-type telencephalon of various sturgeon species; ( Acipenser baeri Br., Acipenser stellatus Pall., Acipenser nudiventris Lov., Acipenser ruthenus L., Acipenser gueldenstaedtii Br., Huso huso L.) were studied by classical histological methods and by TV-imaging. Hemisphere cytoarchitecture was significantly variable across species and genus, while neurone composition proved to be rather conservative. Neurones were mainly of the undifferentiated, isodendritic type. The question of homology of structures between everted and inverted vertebrate telencephala is discussed, and our observations lead us to hypothesise that evolution of the unusual Actinopterygian (and acipenserid) telencephalon has been limited and is, in fact, an evolutionary "dead-end".     

Vascularization and Development of Cytoarchitectonics in the Human Neocortical Rudiment

The development of cytoarchitectonics of the brain rudiments in mammals is accompanied by the formation of an intracerebral vascular network. The relationship between these two processes is insufficiently clear. We studied the development of blood vessels and cytoarchitectonics in the neocortical rudiment of 6- to 13-week old human embryos. The light and electron microscopy methods were used, as well as histochemical visualization of NADPH-diaphorase in the vessel cells. The endothelium proliferation was evaluated using antibodies to proliferating cell nuclear antigen. Starting from week 8 of development, the tangentially oriented vessels formed a intraneural network in the ventricular zone of the rudiment, which appears to restrict the motility of neuroepithelial cells. The basal membrane was initially absent, and the neuroepithelial cells were in direct contact with the endothelial cells. During week 9 of development, the tangentially oriented vessels appeared in the intermediate zone. Formations similar to glial legs with short regions of the basal membrane adjoined the walls of inter- and intraneural vessels (note that, according to the published data, glial fibrillary acidic protein is not yet visualized at this stage). Angioarchitectonics depended little on the cell population density in different zones of the rudiment; specifically, the cortical plate did not contain tangentially oriented vessels until week 12–13 of development. The data we obtained suggest that the blood vessels fulfill a special morphogenetic function in the developing neocortex.     

Turnover of ethanolamine phosphoglycerides in different brain areas of adult and aged rats

The turnover of ethanolamine glycerophospholipids (EGP) has been determined in six different cerebral areas of 4-month and 22-month-old rats, by injecting [³H]glycerol together with [¹⁴C]ethanolamine into the lateral ventricle of the brain. The areas examined behave quite differently in respect to their utilization of the most simple precursors of phosphoglyceride biosynthesis. The incorporation of both glycerol and ethanolamine is already complete as early as 2–4 hours and then reutilization begins, at least for the so called fast pools of phosphoglycerides. The different slopes of the specific activity of the two precursors in EGP suggest a high degree of variance among catabolic rates in the different brain regions. In aged rats the utilization of the water-soluble precursors of EGP synthesis decreases in all brain areas and these data suggest that aging may have a different effect on the catabolic activities as well as phospholipid biosynthesis.     

Atrophy of the thymus in rats rendered diabetic by streptozotocin

The thymus atrophied rapidly in rats rendered diabetic by a single injection of streptozotocin. The weight of the gland was reduced to one-fifth of its original weight within three weeks. Histologically there was a great loss of cortical thymocytes and a marked increase in mast cells lying in the thickened fibrous tissue. These findings may have a bearing on the state of immune deficiency observed in animals with diabetes induced by streptozotocin.     

Free thymidine in the blood serum of irradiated rats with different levels of cellular depletion of the thymus and spleen

The levels of the postirradiation thymidinemia, with an equal degree of the proceeding cell depletion of lymphoid organ tissues caused by the administration of dexamethasone and exposure of rats to 3 Gy radiation, markedly varied. Three days after the injection of the hormone, the organism responded to irradiation by an increase in the concentration of thymidine in blood serum in the same manner as intact animals did. The preirradiation with a dose of 3 Gy reduced sharply the ability of the organism to respond the repeated irradiation (after 3 days) by thymidinemia. There was a lesser increase in the thymidine concentration in the blood after the injection of dexamethasone than after irradiation inducing the same cell depletion of the thymus and spleen.     

The role of the thymus medulla of newborn rats in lymphocytopoiesis

By means of 3H-thymidine, radioautographic investigation of lymphocytopoiesis has been performed in the cortex and medulla of the rat thymus for 2 weeks after birth. In the newborn animals the index of labelled nuclei (ILN) in the medulla is higher than in the cortex. By the 14th day after birth a progressive drop of lymphocytes including the isotope takes place in the medulla. The decrease of ILN in the medulla occurs against the background of increasing amount of epithelioreticulocytes with vacuoles and dystrophic changes in the nucleus and cytoplasm, that make groups of Hassal's bodies.