Tecto-thalamo-telencephalic visual system of the brain in 13-day-old chick embryos

Light and electron microscopic studies have been made of the nervous tissue in three parts of the tecto-thalamo-telencephalic visual system--i.e. tectum opticum, nucleus rotundus of thalamus and ectostriatum of telencephalon--of 13-day chick embryos. Neuroblasts and neurones at various stages of differentiation were described together with various types of synaptic and nonsynaptic intercellular contacts in the neuropil of these brain structures. Heterochronous maturation of these parts of the visual system in embryogenesis was noted which reflects the level of their phylogenetic maturity. Being phylogenetically more ancient structures, tectum opticum and nucleus rotundus reveal differentiation earlier than ectostriatum which is phylogenetically younger.     

Sleep and wakefulness in Greenland seal pups

ECoG of both hemispheres, EOG, neck EMG and EKG were recorded in 2 white (age 10 days) and 2 gray pups (age 1 month) of harp seal. The active wakefulness occupied 23.4 +/- 3.8% of total recording time, the relaxed wakefulness--32.6 +/- 3.6%, drowsiness--4.8 +/- 1.1%, slow wave sleep--31.5 +/- 3.0%, paradoxical sleep--7.7 +/- 0.8%. The sleep cycle averaged 18.2 +/- 1.4 min. Interhemispheric asymmetry of the ECoG was not seen in all 4 pups. The respiration was fast and regular in the relaxed wakefulness, then long respiration pauses were alternated with episodes of hyperventilation during slow wave sleep and there was rare and irregular respiration in the paradoxical sleep. The heart rate was lowest during the paradoxical sleep. It is suggested that this pattern of sleep, allowing seals to delay their breathing during sleep for a long time may be considered as an adaptation to existence in freezing seas.     

Action of toxic staphylococcal (St. aureus) substances on the functional properties of the thrombocytes

The effect of toxic substances from St. aureus on morphofunctional properties of platelets has been studied in vitro. The toxic substances have been shown to induce platelet aggregation and stimulate their secretion. The platelets are transformed from discs to spheres with small pseudopodia. It is believed that platelet aggregation and secretion play an essential role in hemostasis and microcirculation disturbances.     

The thrombocyte-activation factor and endotoxin-induced thrombocyte activation

The effect of PAF in aggregation of platelets induced by endotoxin was studied in experiments in vitro. It is indicated that in high concentration (1.10(-7)-1.10(-6) M) PAF did not affect the degree of aggregation of platelets induced by lipopolysaccharides (LPS) S. typhimurium and N. meningitidis. Successive addition to PRP LPS and PAF or joint addition of PAF and LPS did not change the degree of aggregation of each inductor or their sum. A lower concentration of PAF (1.10(-11)-1.10(-9) M) and endotoxin caused a more expressive aggregation of platelets than their successive addition. Stimulating activity of PAF on endotoxin-induced aggregation, perhaps, is caused by involvement of metabolism of arachidonic acid during blood platelets activation.     

The variation in chum salmon Oncorhynchus keta (Walbaum) mitochondrial DNA and its connection with the paleogeographic events in the Northwest Pacific

The results of examining mtDNA variation in populations of chum salmon Oncorhynchus keta from the rivers of the basins of the seas of Japan and Okhotsk and in the chum salmon seasonal races of the Amur River are presented. A significant level of polymorphism between the majority of the populations studied was detected. The groups of chum salmon from the Japan and Okhotsk Seas displayed the most pronounced differences. Analysis of genetic variation demonstrated that periodic paleontologic and climatic changes in the past of this region were the most probable factor that caused the divergence of these populations. The advances and retreats of glaciers and the accompanying regressions and transgressions of the ocean level caused isolation of chum salmon in the refugia belonging hypothetically to the paleo-Suifun and paleo-Amur regions. These population groups diverged presumably 350-450 thousand years ago. Differences between the seasonal races of the Amur chum salmon are insignificant, and their emergence dates back to the period of the last Wisconsin glaciation. Probably, the main isolation factor now is the genetically determined time of spawning.     

Effect of riboxine on processes of lipid peroxidation and activity of antioxidant enzymes in thymocytes of rats with radiation injury

The disorders of oxidative homeostasis with accumulation of lipid peroxidation products upon depletion of functional capacity of antioxidant defense in thymus lymphocytes after irradiation in doses of 1.0 and 7.78 Gy were shown. The riboxine injection leads to normalization of balance in prooxidant-antioxidant system (with a decrease of formation of lipid peroxidation and activation of antioxidant enzyme system) in early terms after X-ray exposure.