Thermoluminescence of new Al2O3-BeO ceramics after exposure to high radiation doses.

New Al2O3-BeO ceramics were synthesized from alumina nanopowder in BeO crucibles by high-temperature treatment in reducing conditions. It was found that the TL curve of these ceramics is characterized by a dosimetric peak at 520-530 K for a heating rate of 2 K/s. The integrated TL of the peak is not influenced by the heating rate of the samples, unlike that in anion-defective alumina and beryllia crystals. The presence of an energy distribution of the traps which cause dosimetric TL peak is verified by Tm-Tstop and initial rise methods. Linear dependence on dose of the intensity of TL peak at 520-530 K is observed in the 10-300 Gy gamma-dose range. The diversity of TL sensitivity of the ceramic samples synthesized in one cycle does not exceed 10%. The results obtained show that the newly synthesized Al2O3-BeO ceramics are promising materials for TL dosimetry of high doses of ionizing radiation.

Neuroparalytic keratitis and capsaicin.

Subcutaneous injection of 50 mg/kg capsaicin to newborn rats resulted in a marked decrease of heat pain sensitivity and neurogenic inflammation. There was, however, no significant difference between capsaicin-pretreated and control rats in the severity of neuroparalytic keratitis after surgical deafferentation of the eye. Retrobulbar injection of 100 microliters of 0.5% capsaicin produced keratitis-like corneal changes. These changes were not prevented by previous pretreatment with a total subcutaneous dose of 200 mg/kg capsaicin. The findings indicate that corneal changes after deafferentation are not due to excessive release of substance P and other neuropeptides from the degenerating afferent fibres.

[The microcirculatory disorders in deafferentation of the eye]. / Mikrotsirkuliatornye narusheniia pri deafferentatsii glaza.

Microcirculatory disorders occurring in the eye of rats in the early period after deafferentation were studied. The blood flow in the iridic vessels became slower and permeability of the eye vessels was disturbed in the first hours and minutes after retrobulbar injection of the anesthetic trimecaine. Similar changes were encountered in division of the trigeminal nerve branches and in electrocoagulation of the sensory nucleus of the trigeminal nerve as well as in venous congestion induced by applying a ligature to the veins of the eyeball. All these procedures led to corneal edema and development of an inflammatory process. Eye sympathectomy caused neither disorders of vascular permeability nor keratitis. Changes of vascular permeability and tissue edema occurring in the early periods after deafferentation are probably among the causes of the subsequent dystrophic disorders in the peripheral tissue.

[The effect of denervation on ligandin levels and glutathione S-transferase activity in the rat liver]. / Vliianie denervatsii na soderzhanie ligandina i aktivnost' gliutation S-transferazy v pecheni krys.

The authors studied the effect of liver denervation (transection of the hepatic branch of the vagus nerve and/or both splanchnic nerves) on the content of the marker of highly-differentiated hepatocytes--ligandin and the activity of glutathione S-transferase (GT) in rat liver homogenate. The immunodiffusion method demonstrated a decrease in the ligandin level by 21-22% as compared to the value in intact rats 2 weeks after the operation. GT activity was reduced in rats with denervation of the liver but remained unchanged in sham-operated on animals. The results are evidence of diminished biochemical specialization of the tissue of a denervated liver and confirm the role of the peripheral nervous system, the afferent link in particular, in its regulation.

[Development of neuroparalytic keratitis after retrobulbar administration of trimecaine]. / Razvitie neiroparaliticheskogo keratita posle retrobul'barnogo vvedeniia trimekaina.

The blood flow in the iris vessels slowed down and the vessel permeability increased early after a retrobulbar injection of trimecaine, a local anesthetic, this resulting in the development of tissue edema. Two days later neuroparalytic keratitis developed. The authors suppose that early vascular disorders resultant from blocking of the sensitive nerves are among the causes responsible for later changes in the corneal trophics.

[Effect of deafferentation of the liver on hepatocytes located in various parts of the hepatic lobule]. / Vliianie deafferentatsii pecheni na gepatotsity, raspolozhennye v raznykh chastiakh pechenochnoi dol'ki.

Taking into account the data on functional heterogeneity of hepatocytes, situating in various parts of the hepatic lobule, influence of deafferentation of the cat liver on changes in the size of hepatocytes and their nuclei, as well as contents of glycogen and nucleic acids in their cytoplasm have been investigated. The greatest decrease of the glycogen contents and the greatest increase of the nucleic acids and the nuclei volume take place in hepatocytes, situating around the central vein.

[Fluorescence of dopaminergic terminals during elaboration of alimentary conditioned reflexes in the cat]. / Fliuorestsentsiia dofaminergicheskikh terminalei pri vyrabotke pishchevoi uslovnoi reaktsii u krys.

A decrease of intensity of fluorescence of dopaminergic terminals in the nigrostriate and mesolimbic systems of rats was revealed under alimentary deprivation and during conditioned alimentary reaction. This decrease detected against the background of catecholamines synthesis blockade (alpha-methyl-para-thyrosine 40 and 80 mg/kg intraperitoneally) testifies to an activation of dopaminergic terminals and participation of nigrostriate and mesolimbic systems in conditioned alimentary reaction.

[Effect of seduxen on conditioned reflex behavior and reactivity of the noradrenergic system of the rat brain]. / Vliianie seduksena na uslovnoreflektornoe povedenie i reaktivnost' noradrenergicheskoi sistemy mozga krys.

It has been shown in experiments on white rats that administration of diazepam in a dose of 5 mg/kg reduces the emotional stress and activation of noradrenergic terminals during reproduction of conditioned avoidance responses. The role of the central noradrenergic system in the emotional stress control is discussed.

[Emotional-defensive behavior and noradrenergic forebrain structures]. / Emotsional'no-oboronitel'noe povedenie i noradrenergicheskie struktury perednego mozga.

Conditioned avoidance responses in rats increase the noradrenaline expenditure in forebrain. The animals which reproduce no conditioned response after learning as well as the animals with ECS-induced retrograde amnesia preserve the noradrenergic terminals reaction as well as the emotional component of the conditioned response. The extinction of the emotional component by repeated testing or diazepam administration decreases the noradrenergic terminals activation. The data obtained support the view of the noradrenergic system participation in emotional--defensive behaviour.

[Comparative morphometric study of sensory neurons of the cerebral and spinal cord ganglia following transection of their processes]. / Sravnitel'noe morfometricheskoe issledovanie chuvstvitel'nykh neironov cherepno- i spinnomozgovykh uzlov pri pererezke ikh otrostkov

The morphometrical study of sensory neurons g. nodosum of the vagus nerve and spinal ganglia after transection of central and peripheral processes has established similar reactions of the neurons of these ganglia. The sensory neurons respond to the transection of peripheral processes by phenomena of retrograde degeneration. No retrograde degeneration was observed in the neurons after transection of central processes. The diminution of the size of the nerve cell bodies, their nuclei and nucleoli was noted at the period of maximally pronounced phenomena of retrograde degeneration as well as fragmentation and peripheral displacement of the Golgi apparatus, increased amount of satellites adjacent to retrogradely changed neurons.

Analysis of the role of central noradrenergic structures in memory trace recall.

During the reproduction of a conditioned passive avoidance response by albino rats and also during the action of a conditioning stimulus in animals trained by invariable reinforcement of the conditioning stimulus, a significant decrease was found in the noradrenalin content in nuclei of the limbic system and anterior hypothalamus compared with the control. In untrained animals, and also in trained animals subjected to repeated testing in the course of 4 days, the decrease in the noradrenalin content was less marked. Reproduction of the conditioned active avoidence response in a shuttle box did not induce changes in the noradrenalin content.

[Analysis of the participation of rat brain noradrenergic terminals in elaboration of conditioned passive avoidance response]. / Analiz uchastiia noradrenergicheskikh terminalei mozga krys v vosproizvedenii uslovnoi reaktsii passivnogo izbeganiia

A change in a noradrenaline concentration in the noradrenergic terminals was investigated by the fluorescent histochemical method in pars ventralis nuc. interstitialis striae terminalis, nuc. septi lateralis and in nuc. preopticus medialis of male Wistar rats in the process of reproduction of conditioned passive avoidance response. In all the investigated structures of the preliminarily trained animals the reproduction of a conditioned response (without any electrical stimulation) led to a statistically reliable decrease in the noradrenaline concentration. The data obtained testified to the participation of the noradrenergic brain system in the reproductive process of the conditioned passive avoidance response.