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The ultrastructure of neurons, synapses and astrocytes of hippocampal CA1 area in rats was investigated 14 days after: systemic injection of kainic acid and kainic acid and myo-Inositol. After injection of kainic acid numerous neurons with superficial and deep ultrastructural changes of cytoplasmic organelles were described. Among synapses numerous forms with osmiophilic active zone and single synaptic vesicles, also presynaptic terminals with core vesicles were often seen. After kainic acid + myo-Inositol injection the cells with superficial changes of organelles dominated and the synapsoarchitectonics of the area was close to normal. Thus, electrono-microscopic data indicate possible neuroprotective (antiepileptic?) features of myo-Inositol.  相似文献   
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Study of the effects of Cu2+, Zn2+ cations and polyamines, spermine and spermidine, on the nuclear poly(ADP-ribose)polymerase activity of rat brain was carried out. It was shown that low concentrations of Cu2+ stimulate the activity of purified poly(ADP-ribose)polymerase. The poly(ADP-ribose)polymerase activity was increased 1.4-fold at 5 microM Cu2+. A further increase of Cu2+ concentration inhibited the enzymatic activity; at 50 microM Cu2+ the polymerase activity appeared to be fully inhibited. It was shown that Zn2+ inhibited only the poly(ADP-ribose)polymerase activity. Zn2+ at a concentration of 125 microM fully inhibited the enzymatic activity. Spermine and spermidine stimulated the poly(ADP-ribose)polymerase activity of brain nuclei of newborn and old rats.  相似文献   
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Using fluorescent probes it has been shown that free fatty acids cause depolarization of synaptosomes isolated from the rat brain. At the same time free fatty acids stimulated 45Ca2+ transport into synaptosomes. It has been demonstrated that synaptosomes isolated from the brain of E-deficient rats were more sensitive to the action of free fatty acids. Depolarization of synaptosomes isolated from the brain of both control and E-deficient rats were reduced by the addition of exogenous alpha-tocopherol.  相似文献   
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Nestbox provision is a technique used to increase nest-site availability for secondary cavity-nesting birds. However, little is known about the demographic consequences of nestbox provision in different habitat types. To assess how nestbox provision affects the density of hole-nesting birds simultaneously in two contrasting habitats, we compared the breeding density of Great Tits along transects without nestboxes with that in transects where nestboxes were provided. Although the initial density of breeders was considerably higher in the deciduous habitat than in the coniferous habitat, provision of nestboxes increased density by a similar number of additional pairs in each habitat type. Thus, the provision of nestboxes in managed coniferous forests may be as effective in increasing the breeding opportunities of cavity nesters as in deciduous stands. Moreover, previous research showed that pairs in deciduous habitat with nestboxes have consistently lower breeding success than those in coniferous habitat with nestboxes. It is possible that the addition of nestboxes in the preferred habitat increased density to such an extent that density-dependent effects became apparent.  相似文献   
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As a result of the enteral and combined subcutaneous-enteral immunization of adult rabbits with cholerogen toxoid and the specific fraction of chemical cholera vaccine in tablets immunological transformation occurred in the organism and a "protective" barrier consisting of antibody-containing cells was formed in the intestine on days 3-5. The combined method of immunization with cholera vaccine proved to be essentially as effective as enteral immunization in 2 administrations.  相似文献   
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