Association connections of the cat's parietal cortex

Intercortical connections of primary sensory (visual, auditory, somatosensory) areas with the parietal association cortex were studied in cats by the retrograde axonal transport of horseradish peroxidase and the Fink-Heimer silver impregnation of degenerated fibers techniques. This combined study revealed the shape, size, and intracortical location of cells connecting the primary sensory areas monosynaptically with the parietal cortex and also the distribution of preterminals and terminals of the fibers of these cells in the parietal association cortex. The greatest number of cells forming connections with area 7 of the parietal association cortex was shown to occur in visual area V1, and with area 5 in somatosensory area S1. Besides pyramidal neurons tagged with horseradish peroxidase, which were located mainly in layers II–IV, a few tagged stellate and fusiform cells also were found. The results supplement and confirm data on afferent connections of the parietal association cortex in cats.M. Gor'kii Donetsk Medical Institute. Translated from Neirofiziologiya, Vol. 13, No. 1, pp. 3–6, January, 1981.     

The effect of river runoff and phytoplankton production on the seasonal variation of the chemical composition of coastal waters of the Amursky Bay, Sea of Japan

The factors that control the seasonal variability of the concentration of suspended matter, nutrients, dissolved forms of metals and phytoplankton biomass in coastal waters of the eastern part of the Amurskii Bay were determined. It was shown that the runoff of the Razdolnaya River determined the seasonal variability in suspended matter content, values of the chemical oxygen demand (COD), silicates, Fe, Mn, Cu, and Ni significantly affected the concentration of nitrates. The advection of sea water is the main source of phosphates and dissolved forms of Zn and Cd. In the autumn and winter seasons, the gradual decrease in the concentration of silicates and phosphates was related to phytoplankton activity. In the spring and summer seasons, the growth of phytoplankton determined the variability of the phosphate and nitrate contents and compensated for the effect of the Razdolnaya River runoff. It is concluded that the phytoplankton biomass, rather than variations in riverine flow, caused the long-term variability of the nitrate and phosphate concentrations in the coastal waters of the Amurskii Bay.     

Synthesis and membrane protective activity of bis-sulfides derived from monoterpenoids and monosaccharides

Hydroxyl- and chloroethyl derivatives of neomenthane- and isobornanethiol in yields of to 80% were synthesized. They served as the basis for the preparation of new bis-sulfides with diacetone-protected galacto- and fructopyranose fragments in yields up to 98%. The bis-sulfides synthesized were screened for membrane protective and antioxidant properties in a model cell system (in vitro) based on their ability to inhibit the H₂O₂-induced hemolysis of erythrocytes and retard the oxyhemoglobin oxidation.     

Inversion polymorphism and the divergence of two cryptic forms of Anopheles messeae (Diptera, Culicidae) at the level of genomic DNA repeats

Genomic DNA of samples from several populations of malaria mosquito Anopheles messeae belonging to the macullipennis Paleoarctic complex was examined using digestion with ten restriction enzymes and electrophoresis in polyacrylamide gel. The patterns of DNA repeat fraction in the EcoRII hydrolysate in two cryptic forms of An. messeae characterized by common inversion polymorphism were shown to be different. The genomic differences in mixed sympatric groups and those between geographically remote populations of the different forms were identical. No interindividual, intrafamilial, inter- and intrapopulation variation was revealed in either form. The electrophoregrams of individuals belonging to the same the B form but having different combinations of inversion chromosomal variants in the karyotypes were identical. Analysis of taxonprints in the forms showed that individuals with the same karyotype may belong to different forms. These results coupled with evidence on the ecological features of and assortative mating in An. messeae populations demonstrated that the examined forms are not conspecific. Our results indicate that taxonprint analysis is the most reliable and precise test for the presence of conspecific forms in a large sympatric zone.     

Influence of experimental epileptogenesis on memory: the role of lipids in cognitive disorders

Learning and memory disorders accompanying epileptogenesis were studied in rats with the use of two experimental models of epilepsy, picrotoxin kindling and kainic treatment. Rise of exploratory activity and decrease in animal's capability for experimental extinction of a response were characteristic of the initial stage of epileptogenesis. It was suggested that a dysfunction of brain hippocampal system can be responsible for cognitive disorders. To reveal their mechanisms, lipid contents were determined in the neocortex and hippocampus in appropriate periods after exposure to epileptogenic factors. Long-term changes in hippocampal lipid spectrum were found five days after the exposure to kainic acid. In particular, after sodium valproate treatment (the compensation of kainic effects), the total content of phospholipids in hippocampus was decreased. The hippocampal sphingomyelin level dropped as a result of picrotoxin kindling. The sphingomyelin changes suggest some recovery processes in hippocampal cells and point to an adaptive role of membrane lipids in the mechanisms of the damaging epiptogenous effects.     

Synthesis of Some New Thiourea Derivatives and Their Influence on Biological and Genetic Effects of Gamma Rays*

The synthesis of the new radioprotective compounds ATB (I, 2-allylthioureidobenzoic acid), PTB (II, 2-phenylthioureidobenzoic acid), A-2-PTU (III, N-allyl-N"-2-pyridylthiourea), and P-2-PTU (IV, N-phenyl-N"-2-pyridylthiourea) and their influence on biological and genetic effects of gamma rays was studied. In result of investigations it must be noted that PTB displayed radioprotective effect as a result of which more plants in M₁ germination and survive in M₂ of the induced mutations is increased. The cytological analysis reveals that the studied substance (PTB) decreases chromosome aberration in meristem cells of pea roots almost twice as a result of postirradiation treatment. The effect of A-2-PTU in the experiments with peas greatly depends on the dose of irradiation, i.e., on the degree of damaging of the processes of cell restoration and the possibility of their partial restoration after the treatment with the protector. The results obtained suggest that chemical compounds of N,N"-disubstituted thiourea group (A-2-PTU and P-2-PTU) exert strong radioprotective effect in the experiments with peas. This is of great importance to modern radiobiology and radiation mutagenesis and also to protect hereditary structures against radiation.