Activity of Phosphate-Dependent Glutaminase in the Brain of Rats Exposed to Prenatal Hypoxia during Organogenesis.

We studied the effect of hypoxia (days 9-15 of pregnancy) on phosphate-dependent glutaminase activity in the brain of rat offspring aging 18 days and 1, 3, and 6 months. Activity of glutaminase significantly increased in mitochondria from the orbital, visual, and limbic cortex, hypothalamus, and midbrain of 17-day-old offspring. Activity of this enzyme in all brain regions increased at the age of 1 month, but significantly decreased in animals aging 3 and 6 months and prenatally exposed to hypoxia (during organogenesis). Changes in glutaminase activity in various structures of the brain are probably associated with activation of the glutamatergic and GABAergic systems and serve as an adaptive and compensatory reaction of the brain.

[Study of visual perception under conditions of extreme light exposures].

Neurophysiological processes of transduction and analysis of information concerning brightness of photostimuli and peculiarities of functioning of visual system under exposure to extra-bright light effects or extreme contrasting of visual objects are studied poorly and present significant interest for unraveling actual mechanisms of visual perception under extreme conditions. Conducting analysis of visual system in maximal broad range both in terms of adequate perception and reflection of light stimulus intensity and adaptive mechanisms to extra-strong illumination regimes is as well very important. The to-date obtained data indicate that under the extreme light effects pathology of the peripheral portion of visual analysator can be induced. The presented review does not pretend to comprise all present information concerning all achievements and results over this problem. Its goal concludes in maximal approaching to understanding the mechanisms of damaging and following recover of visual function under extreme effects of affecting light factors.

[The distribution of aspartate aminotransferase activity in the structures of the visual analyzer in the canine brain during postnatal ontogeny]. / Raspredelenie aspartataminotransferaznoi aktivnosti v strukturakh zritel'nogo analizatora mozga sobak v period postnatal'nogo ontogeneza.

Studies have been made on aspartate aminotransferase activity in light and heavy synaptosomes, membrane and synaptic mitochondria from the visual cortex (field 17), bigeminal bodies, and outer geniculate body. It was shown that the enzymic activity significantly decreases in all the subfractions investigated in puppies beginning from 6 months up to 1 year. In earlier postnatal ontogenesis, the activity increased in all the subfractions, the extent of the increase being dependent on the source of the enzyme.

[Complex endoscopic ultrasonographic diagnosis of esophageal diseases]. / Kompleksnaia éndoskopicheskaia ul'trazvukovaia diagnostika zabolevanii pishchevoda.

Complex endoscopic and transesophageal ultrasonic examination makes it possible to identify distinctly the character and localization of the pathological process, its boundaries and its spread to the adjoining organs. Ultrasonic examination is especially effective in new growths of the esophagus.

[The effect of early visual deprivation on the level of N-acetyl-1-asparaginic acid and the activity of phosphate-activated glutaminase in visual analyzer structures and various regions of the dog cerebral cortex and cerebellum]. / Vliianie rannei zritel'noi deprivatsii na soderzhanie N-atsetil-1- asparaginovoi kisloty i aktivnost' fosfataktiviruemoi glutaminazy v strukturakh zritel'nogo analizatora i raznykh oblastiakh kory golovnogomozga i v mozzhechke sobaki.

Under conditions of 45-days visual deprivation content of N-acetyl-L-aspartic acid was considerably increased in visual cortex (field 17) tissues and decreased in the superior colliculus and exterior geniculate body. At the same time, content of N-acetyl-L-aspartic acid was not altered in the visual cortex mitochondrial fraction; in the outer structures studied level of this amino acid was distinctly decreased both in tissues and mitochondrial fractions. After prolongation of the visual deprivation up to 90 days content of N-acetyl-L-aspartic acid was sharply decreased in tissues and mitochondrial fractions of all the formations studied of dog brain visual analyzer. The maximal 4.5-fold decrease was found in mitochondrial fractions of the visual analyzer (field 17), in the exterior geniculate body and superior colliculus content of the amino acid was decreased 2.4-3.9-fold as compared with controls. In 90 days-long visual deprivation total activity of phosphate-dependent glutaminase was considerably increased (1.18-3.71-fold as compared with controls) in myelinic (A), membraneous (B), light (C), and heavy synaptosomal and synaptic mitochondrial (E) subfractions of the visual cortex (field 17). The rate of the enzyme activation was distinctly higher in these subfractions as compared with that of the motor and parietal cortical subfractions. After 90 days-long visual deprivation the similar alterations were found in A, B, D and E cerebellum subfractions but these alterations were less distinct as compared with the visual, motor and parietal subfractions.

[Transesophageal ultrasonography in the diagnosis of esophageal and cardial tumors]. / Transézofageal'naia ul'trasonografiia v diagnostike opukholei pishchevoda i kardii.

Results of complex examination of 92 subjects with suspected pathology of the esophagus and cardia are presented. Endoscopic and ultrasonographic examination identified cancer in 31 patients. Site and extent of tumor as well as invasion of adjacent structures were assessed, too.

[Subcellular distribution of the phosphate-activated glutaminase activity in the visual analyzer of the brain during postnatal ontogenesis in dogs]. / Subkletochnoe raspredelenie aktivnosti fosfataktiviruemoi glutaminazy v zritel'nom analizatore mozga sobak v period postnatal'nogo ontogeneza.

The level of general activity of phosphate-activated glutaminase (PAG) on the 1st postnatal day was higher in heavy and light synaptosomes of the exterior geniculate body (EGB) and lower--in the superior colliculus (SC) and visual cortex (field 17); in the subfractions of synaptic mitochondria (E) the general activity of the enzyme was higher in EGB and lower in the visual cortex (field 17) and SC. The level of general activity of the enzyme in the subcellular formations and certain formations of the visual analyzer on the 1st postnatal day was different. This difference varied in the course of postnatal development of the visual system in dogs. The PAG general activity in the subfractions of light (C), heavy (D) synaptosomes, synaptic mitochondria of the membranous enzymes and small synaptosomes sharply enhanced in the visual cortex (field 17) of SC and EGB from the 1st to the 12-14th postnatal days, the subfractions C and D of the visual cortex (field 17) showing the highest degree of the enzyme activity up to the 45th day. SC and EGB subfractions showed a considerable decrease in the enzyme activity of dogs aged 3 months; this peculiarity persisted up to the 6-month age in the above formations, especially in the subfractions B, C, D and E. Dogs aged 1 year exhibited a sharper decrease in the general activity of the enzyme of formations C, D, E in EGB and SC. It was established that with an advance of age the general activity of the enzyme in myelin subfractions (A) mostly increased, especially in the visual cortex (field 17) and EGB of dogs aged 1 year and in SC of dogs aged 6 months.

[The effect of early visual deprivation on the synthesis of glutamic and aspartic acids in mitochondria of central structures of the visual analyzer in the dog]. / Vliianie rannei zritel'noi deprivatsii na sintez glutaminovoi i asparaginovoi kislot v mitokhondriiakh tsentral'nykh struktur zritel'nogo analizatora mozga sobak.

After 45 days visual deprivation synthesis via direct reductive amination and transamination of glutamic and aspartic acids was inhibited in mitochondria of dog visual cortex, colliculi anterioris and corpus geniculatum externus. Under conditions of long-term (90 days) visual deprivation synthesis of glutamic and aspartic acids was less effectively inhibited in mitochondria of the brain areas studied via the reductive amination and transamination, except of the aspartic acid synthesis by means of transamination, the rate of which was maintained at the level similar to the values observed after 45 days of visual deprivation.

[Synthesis of glutaminic and aspartic acids in mitochondria of the visual analyzer of the dog brain during postnatal ontogenesis]. / Sintez glutaminovoi i asparaginovoi kislot v mitokhondriiakh struktur zritel'nogo analizatora mozga sobak v postnatal'nom ontogeneze.

It is revealed that glutaminic acid (GA) synthesis by direct reductive amination proves to be the most rapid in the mitochondria of the outer geniculate body (OGB) from the 1st till the 45th day of the postnatal development, and beginning from the 45th day till the 3-month age in visual cortex (field 17) (VC) and bigeminal bodies (BB). It is stated that GA synthesis by transamination in the mitochondria of VC, OGB, and BB proceeds less intensively than by a direct reductive amination at the early stage of postnatal development, being more rapid during the period from the 12-16th till the 45th day of postnatal development. Unlike GA synthesis in the mitochondria of the studied visual analyzer structures of canine brain AsA synthesis is more rapid in transamination reaction at the early stage of postnatal development. The high level of AsA synthesis was observed on the day when the puppies' eyes began to see clearly. The level of AsA synthesis by reductive amination and transamination in the mitochondria of VC, BB, and OGB at the early stage of postnatal development is lower than that of GA synthesis.

[Glutamate decarboxylase activity in subcellular fractions of tissues of brain visual analyzer in dogs during postnatal ontogenesis]. / Aktivnost' glutamatdekarboksilazy v subkletochnykh fraktsiiakh tkanei ritel'nogo analizatora mozga sobak v postnatal'nom ontogeneze.

Fractions of mitochondria, synaptosomes and fragments of membranes isolated from structures of dog brain visual analyzer in the postnatal ontogenesis period differs in the glutamate decarboxylase activity. Till the 45th day of development it rises, as a rule, in all the fractions under study and then it lowers. An increase in the activity in most cases is more pronounced in subfractions of heavy synaptosomes and fragments membrane. The enzyme activity in the visual cortex (field 17), anterior corpora bigemina and external geniculate body rises differently. In one-day animals GABA is formed in the fraction of heavy synaptosomes of anterior corpora bigemina and external geniculate body with a higher intensity than in the visual cortex area (field 17) that may be associated with earlier GABA accumulation in GABA-ergic neurons of subcortical structures of the visual analyzer than in its cortical structures.

[Glutamate decarboxylase activity in subcellular fractions of tissue of brain visual analyzer of dogs subjected to visual deprivation]. / Aktivnost' glutamatdekarboksilazy v subkletochnykh fraktsiiakh tkanei ritel'nogo analizatora mozga sobak pri zritel'noi depreivatsii.

Glutamate decarboxylase activity in fractions of mitochondria, synaptosomes and membranes fragments of tissues brain visual analyzer central structures of the dog was found to decrease during visual deprivation. A degree of the decrease is different and depends on the deprivation duration. During a 45-day deprivation the specific activity of the enzyme lowers significantly in all subfractions, decrease is especially sharp in subfractions of heavy synaptosome and membranes (by 71-85%). The decrease in the activity is more pronounced in the anterior corpora bigemina and in external geniculate body than in the cortex visual area (field 17). During a 90-day deprivation the activity lowers in all the structures but to a less extent than during the 45-day deprivation. The specific activity in subfractions of heavy and light synaptosomes is 40-67% lower than normal and in the membrane and mitochondrial subfractions differs slightly. In the visual deprived dogs the intensity of GABA formation reduces in all the subfractions, the decrease being higher during the 45-day deprivation.

[Effect of early visual deprivation on GABA transaminase activity in the brain structures of dogs]. / Vliianie rannei zritel'noi deprivatsii na aktivnost' GAMK-transaminazy v nekotorykh obrazovaniiakh mozga sobak.

Activity of GABA-transaminase was distinctly decreased as compared with controls in all the brain structures studied in animals growing under conditions of early visual deprivation. At the same time, alterations were developed in synthesis of glutamic and aspartic acids and in their ratio. Biosynthesis of glutamic acid was decreased 2-fold in parietal cortex region and in cerebellum of 45 day-old animals, less distinct decrease in the amino acid synthesis was observed in the locomotion brain region of the animals as compared with controls. At an age of 90 days, to the contrary, most distinct decrease (3-fold) in glutamic acid synthesis occurred in the locomotion region and a less distinct decrease - in cerebellum. Synthesis of aspartic acid was less distinctly altered in the deprived animals; it was decreased in cerebellum of both age groups of animals, in parietal cortex region - only in the group of 90 day-old animals and unaltered - in locomotion region of both animal groups. The values of the glutamic/aspartic acid ratio were also decreased. The pattern was quite similar in all the brain structures studied of 45 day-old animals; in the 90 day-old animals the corresponding ratios of the amino acids were increased in cerebellum, only slightly increased - in locomotion region of brain cortex and they were decreased in parietal cortex region.

[Effect of early visual deprivation on glutamate decarboxylase activity in the visual analyzer of the brain]. / Vliianie rannei zritel'noi deprivatsii na aktivnost' glutamatdekarboksilazy v zritel'nom analizatore mozga.

Early vision deprivation decreased in dogs (45-days age) the activity of glutamate decarboxylase in all the structures of brain visual analyzer studied as well as decreased the enzyme activation by exogenous pyridoxal-5-phosphate. With areing (in 90-days old dogs) the deprivation proved to be less effective in relation to decrease in the glutamate decarboxylase activity in external geniculate body but caused the same affect in the visual zone of brain cortex and in anterior mesencephalon. The deprivation exhibited similar effect on formation of asparaginic acid.

[Glutamate decarboxylase activity in the central structures of the dog brain visual analyzer in the early period of postnatal ontogenesis]. / Gutamatdekarboksilaznaia aktivnost' v tsentral'nyky strukturakh zritel'nogo analizatora mozga sobak v rannii pernod postnatal; nogo ontogeneza.

In puppies the first day after birth the glutamate decarboxylase activity in all the studied structures of the brain visual analyzer is the same. On the 12-16th day of the postnatal development it is higher in the corpora bigemina anterior and in the lateral geniculate body than in the optic cortex. The level of GABA formation with pyridoxal-5-phosphate added in the corpora bigemina anterior and lateral geniculate body reaches its maximum on the 21st day of the postnatal development and in the optic cortex (field 17) at the age of three months. The highest amount of asparaginic asic with pyridoxal-5-phosphate added is formed in the optic cortex (field 17) by the 45th day of development and in the corpora bigemina anterior and geniculate body by the 90th day of life.

[GABA-transaminase activity in the dog brain visual analyzer following light deprivation during ontogenesis]. / GAMK-transaminaznaia aktivnost' v zritel'nom analizatore mozga sobak pri svetovoi deprivatsii v ontogeneze.

The GABA-transaminase activity is the highest in the subcortical formations of the brain visual analyzer in 45- and 90-day dogs. Deprivation of visual impulses at early stages of postnatal ontogenesis lowers sharply this activity in all the studied areas of the brain visual analyzer. Under conditions of deprivation the content of glutaminic acid increases in all the formations of the dog brain visual analyzer to a considerably less extent, especially in the anterior corpora bigemina and lateral geniculate body at the age of 45- and 90-days. Similar regularities are found in the deprivation effect relative to formation of ascorbic acid the content of which lowers sharply in all the formations of the dog brain visual analyzer on the 90th day of light deprivation.

[Age and changes in the concentration of dicarboxylic amino acids and GABA in different portions of the dog cerebral cortex and cerebellum]. / Vozrastnye izmeneniia soderzhaniia dikarbonovykh aminokislot i GAMK v raznykh uchastkakh kory golovnogo mozga i mozzhechke sobak

The content of dicarboxylic amino acids lowers with age in all the structures of cerebral cortex and cerebellum under study when calculating per I g of fresh tissue and 100 mg of protein. The greatest decrease in the amount of glutaminic and aspartic acids is found in the parietal region at the senile age. The content of GABA in all the brain structures of three-year dogs is significantly higher than in the one-year dogs and at the senile age it is somewhat lower as compared to the three-year animals when calculating per 1 g of fresh tissue, the degree of the decrease in all the studied regions being practically the same.

[Effect of early visual deprivation on the free amino acid and protein content in the brain formations of dogs]. / Vliianie rannei zritel'noi deprivatsii na soderzhanie svobodnykh aminokilsot i belkov v obrazovaniiakh mozga sobak

10 days old dogs were subjected to bilateral enucleation of eyeballs. When the dogs became 3 months old, content of free amino acids and total proteins was determined in tissue of brain formation of optic system (optic cortex-field 17, external knee body and front bigeminal bodies). locomotor and partietal regions of brain cortex and cerebellum. As compared with the control group, the amount of proteins was distinctly decreased in optic cortex and increased in external knee body. In all he brain formations studied content of arginine, lysine, gamma-aminobutyric acid, cysteine (except of external knee body) and histidine (except of external knee body and front bigeminal bodies) was distinctly increased. The decrease in content of glutamic acid was observed only in front bigeminal bodies and aspartic acid -- in cerebellum. Glutathione was accumulated selectively in front bigeminal bodies and in locomotor cortex.