bluuebunny/crossref_metadata_2025_split huggingface dataset:
UNTERSUCHUNGEN DES GLUTAMATSTOFFWECHSELS IN VERSCHIEDENEN HIRNAREALEN DES HUNDES IM PRÄKONVULSIVEN ZUSTAND METABOLIC INVESTIGATIONS OF EPILEPTIC SEIZURES Investigations of Glutamate Metabolism in Regions of the Dog Brain in Preconvulsive States
Authors: Wiechert und P. , Gölnitz G. 
Published: October 2006

Zusammenfassung —Die Aktivitäten der Glutamat‐Decarboxylase, Glutamat‐Oxalacetat‐Transaminase, Glutamat‐Pyruvat‐Transaminase, Glutamat‐Dehydrogenase und Glutamin‐synthetase sowie die Konzentration der freien Aminosäuren und des Ammoniaks wurden in neun Hirnregionen des Hundes (Amygdalae, Thalamus, Nucleus caudatus, Hippocampus, Temporalpol, Gyrus cinguli, Kleinhirnmark, Kleinhirnrinde, Medulla oblongata) in der präkonvulsiven Phase nach intracisternaler Injektion von l‐Glutamat bzw. Pyridoxal‐5‐phosphat bestimmt.Sechs der neun untersuchten Gebiete zeigten keine auffälligen Stoffwechselveränderungen. Lediglich im Amygdalae, Hippocampus und in der Medulla oblongata konnten deutliche Unterschiede verschiedener Enzymaktivitäten und Substratkonzentrationen beobachtet werden. Die Erhöhung des Glutamats im Hippocampus erscheint wegen der Übereinstimmung mit den an den Rattengehirnen gefundenen Veränderungen am wichtigsten und wird als möglicher Ausgangspunkt für einen cerebralen Anfall diskutiert.Abstract —The activities of glutamate decarboxylase, aspartate aminotransferase (glutamic‐oxalacetic transaminase), EC 2.6.1.1 alanine aminotransferase (glutamic‐pyruvic transaminase EC 2.6.1.2), glutamate dehydrogenase and glutamine synthetase, as well as the concentration of free amino acids and ammonium were determined in nine regions of the dog brain (nucleus amygdalae, thalamus, nucleus caudatus, hippocampus, temporal lobe, gyrus cinguli, cerebellar marrow, cerebellar cortex, medulla oblongata) in the preconvulsive phase after injections of l‐glutamate and pyridoxal‐5‐phosphate.In six of the nine regions examined there were no considerable metabolic changes. Marked changes in different enzyme activities and substrate concentrations were observed in the nucleus amygdalae, hippocampus and medulla oblongata. The increase of glutamate in the hippocampus seems to be of great importance in view of the agreement with alterations found in the brains of rats, and this is regarded as a starting point for cerebral seizures.
FORMATION AND TURNOVER OF MYELIN GANGLIOSIDE*
Authors: Suzuki Kunihiko 
Published: October 2006

Abstract—In young adult rats, the formation and turnover of GM1‐ganglioside in myelin were compared with the formation and turnover of GM1‐ganglioside in whole brain and of total lipids in whole brain and myelin, after injection of d‐[1‐14C]glucosamine. During the first 24 hr after injection, the specific activity of GM1‐ganglioside in myelin was less than 25 per cent of that of GM1‐ganglioside in whole brain. The specific activity of ganglioside in whole brain was maximal at 24 hr and then declined steadily during the next 3 months, whereas the specific activity of GM1‐ganglioside in myelin continued to increase and did not reach a peak until about one month after injection, by which time its specific activity had increased five‐fold. Consequently, the specific activity of GM1‐ganglioside in myelin was 50 per cent higher than ganglioside in whole brain after one month. These differences in the formation and turnover of GM1‐ganglioside in myelin and of whole brain are similar to those of other lipids of myelin and of whole brain, indicating that the metabolic activity of myelin ganglioside is similar to myelin lipids, but differs from whole brain lipids or whole brain gangliosides. These data provide additional evidence that ganglioside in myelin is an intrinsic constituent of the myelin sheath. GT1 (G1), GD1b, (G2), GD1a (G3), GM1 (G4), GM2 (G5), GM3 (G6).
APPEARANCE OF A BRAIN SPECIFIC ANTIGEN (THE S‐100 PROTEIN) DURING HUMAN FOETAL DEVELOPMENT1
Authors: Zuckerman J. E. , Herschman H. R. , Levine L. 
Published: October 2006

Abstract—The concentration of a protein specific to brain, the S‐100 protein, was measured in various regions of the human foetal brain at gestational ages ranging from 10 weeks until term. The relative increase in concentrations of the S‐100 protein during development of the human foetal brain proceeded in a caudal‐rostral fashion. This observation is emphasized by the delayed appearance of the S‐100 protein in the frontal cerebral cortex until the 30th week of gestation.
SELECTIVE RETENTION OF OESTRADIOL BY CELL NUCLEI IN SPECIFIC BRAIN REGIONS OF THE OVARIECTOMIZED RAT1
Authors: Zigmond R. E. , McEwen B. S. 
Published: October 2006

Abstract—Cell nuclei were isolated from four regions of the brains of ovariectomized female rats 2 hr after the injection of [3H]oestradiol. By light microscopy, the nuclear pellets contained highly purified nuclei of neuronal and glial cells with little cytoplasmic contamination. Tritium was concentrated in cell nuclei from the preoptic‐hypothalamic area, to a lesser extent in nuclei from the amygdaloid region and hippocampus, and least of all in cerebral cortical nuclei. In comparison with whole homogenates (= 1‐0), the nuclear concentrations of radioactivity were 12·9, 4·7, 1·9 and 0·8, respectively. Approximately 40 per cent of the radioactivity in homogenates of the preoptic‐hypothalamic area was present in cell nuclei, and upon TLC more than 85 per cent of the radioactive material in the nuclei exhibited the RF of oestradiol‐17β.Pretreatment of ovariectomized females with 1 mg of unlabelled oestradiol 30 min before the injection of labelled hormone abolished the nuclear uptake of [3H]oestradiol in all four regions of the brain. A concurrent injection of 10 μg of unlabelled oestradiol‐17β significantly reduced nuclear uptake, while a similar injection of testosterone or oestradiol‐17α had no significant effect. One mg of oestradiol‐17α, but not testosterone, did reduce nuclear uptake.The retention of [3H]oestradiol by the preoptic‐hypothalamic area decreased exponentially in the tissue from 30 min to 4 h after an intraperitoneal injection; however, nuclear binding reached a peak at 1‐2 h and still showed high retention at 4 h. These results, together with observations in other laboratories of morphological changes induced by oestrogens, establish that certain regions of the brain are bona fide targets for the action of oestradiol.
CALCIUM CONTENT AND EXCHANGE IN NEOCORTICAL TISSUES DURING THE CATION MOVEMENTS INDUCED BY GLUTAMATES
Authors: Ramsey R. L. , McIlwain H. 
Published: October 2006

Abstract—

Guinea pig neocortical tissues incubated in glucose‐bicarbonate media reached stable calcium contents of 2 μat./g of which 0‐35 μat.Ca/g was in a space accessible to inulin.
Addition of l‐glutamate salts caused a prompt increase in intracellular calcium at rates up to 7 μat./g tissue/hr.
Using 45Ca, this increase was found to be due to an accelerated influx of Ca and a diminished efflux. The rate of influx could be doubled by 1 mm‐l‐glutamate.
Tetrodotoxin at concentrations of 66‐330 nM diminished 45Ca entry, both in the absence and presence of added glutamate.
Tissue sodium and potassium contents are also reported under some conditions, and the extent to which calcium may condition sodium and potassium movements is discussed.
FORMATION OF ASPARAGINE FROM ASPARTIC ACID IN RAT BRAIN
Authors: Benuck M. , Stern F. , Lajtha A. 
Published: October 2006

Abstract—The synthesis of asparagine in rat brain was studied both in vitro and in vivo. A conversion in vitro of about 2 per cent of the added l‐[14C]aspartic acid into asparagine was found after a 2 h incubation with the 100,000 g supernatant fraction from brain. This corresponded to a formation of 4·8 nmol of asparagine/mg of protein/h. The reaction required ATP and glutamine, and was linear with time during the 2 h incubation. When the crude mitochondrial fraction was added to the incubation mixture the reaction was inhibited, probably because of the presence of ATPase activity in the mitochondrial preparation. Inhibition by the reaction product seemed unlikely since removal of endogenous asparagine did not stimulate the reaction; only when asparagine was added at levels of 0·5 or 1·0 mm was significant inhibition found. Ammonium chloride was less effective than glutamine as an amide donor. Endogenous asparaginase (EC 3.5.1.1.) activity was low in the in vitro preparation and did not significantly affect the conversion. Synthesis of asparagine from aspartic acid did not occur in slices of brain nor was there a significant conversion of aspartic acid or glucose to asparagine after their intracerebral administration in vivo.
CHOLINE ACETYLTRANSFERASE IN INDIVIDUAL NEURONS OF APLYSIA CALIFORNICA1
Authors: McCaman R. E. , Dewhurst Susan A. 
Published: October 2006

Abstract—The activities of choline acetyltransferase in the various ganglia of the nervous system of Aplysia californica and in some of the individually identifiable neurons in these ganglia were measured. At least four of the neurons were characterized by an apparent absence of the enzyme. The neurons containing measurable amounts of the enzyme had reproducible levels from animal to animal. Individual neurons from the same animal were generally characterized by different levels of activity whether expressed on a cell or a protein basis. However, those pairs of neurons previously classified as ‘homologous’ because of their similar appearance, location and/or electrophysiological function, also contained the same total amounts of enzyme activity.
STUDIES ON THE TURNOVER OF MOUSE BRAIN SYNAPTOSOMAL PROTEINS1
Authors: Morris S. J. , Ralston H. J. , Shooter E. M. 
Published: October 2006

Abstract—(l) The half‐lives of the proteins of various fractions of whole mouse brain increase with increasing insolubility; the supernatant and hypotonic‐extractable proteins had half‐lives of about 13 days, whereas the membrane proteins solubilized with Triton X‐100 and SLS had half‐lives of about 18 days. The proteins of the subfractions of synaptosomes had half‐lives ranging from 15 to 19 days; those in the cytoplasm had a half‐life of 18·3 days, in the membranes, about 17 days and in the synaptic vesicles, 15·6 days.(2) Although the half‐life of the synaptic vesicles was not significantly different from that of other synaptosomal subfractions, the vesicles exhibited a different protein pattern on acrylamide gels, an observation which implies that the proteins of the vesicles are qualitatively different from those of other synaptic membranes.(3) The uptake of labelled lysine into the cytoplasm of the synaptosomes of youg mice in vivo was very rapid.(4) The data derived from the relative specific radioactivities of synaptosomal fractions compared with their whole brain analogs support the contention that a sizeable fraction of the synaptosomal cytoplasmic protein was transported to the synapse by axoplasmic flow. The relative specific radioactivities of synaptosomal membrane and synaptic vesicle proteins rose much more quickly than the comparable activities for the cytoplasmic material, and the alternate possibility of synthesis in situ is discussed.
ENZYME ALTERATIONS AND LIPID STORAGE IN THREE VARIANTS OF TAY‐SACHS DISEASE
Authors: Sandhoff K. , Harzer K. , Wässle W. , Jatzkewitz H. 
Published: October 2006

Abstract—In autopsy tissues of 12 cases of Tay‐Sachs disease the N‐acetyl‐β‐hexosamini‐dase A and B activities were investigated using chromogenic and physiological substrates.In three cases of Tay‐Sachs disease, classified as the variant O, the enzyme activities A and B were missing; in eight cases, classified as the variant B, the enzyme activity A was missing. In another case, both enzyme activities wcre shown to be enhanced in brain tissue (‘variant AB’), using a chromogenic substrate.The three enzymic variants showed different glycolipid storage patterns of Tay‐Sachs‐ganglioside (TSG) and its asialo residue, the trihexosylceramide (THC) in the nervous tissues. Additional storage of kidney globosidc was found in the visceral tissues of the O variant. A decrease of the non‐accumulated lipids, especially of those characteristic for myelin, was observed. The quantitative lipid determinations were performed by means of a thin‐layer densitometric micromethod (standard deviation 2–5 per cent).Evidence is presented that the different storage patterns result from the corresponding enzyme alterations in the three variants. An essential condition for this statement was the isolation of the storage compounds from Tay‐Sachs tissues and their radioactive labelling by the addition of tritium to the double bond in their sphingosine moiety. In a previous investigation it was shown that enzyme A degrades the storage compounds TSG, THC and kidney globoside while enzyme B acts on THC and kidney globoside only. In agreement with this finding, a highly concentrated mixture of both enzymes from normal tissues hydrolyses the main storage compound, the Tay‐Sachs‐ganglioside. This hydrolysis was reduced when corresponding enzyme preparations from tissues of variants of Tay‐Sachs disease (including variant AB) acted on TaySachs ganglioside.Some properties of the N‐acetyl‐β‐D‐hexosaminidases from normal and from pathological tissues were determined with chromogenic and physiological substrates. The relationship between the enzymes A and B is discussed.
ON ARABINOSE AS A CONSTITUENT OF HYALURONIC ACID FROM BOVINE BRAIN
Authors: Katzman R. L. 
Published: October 2006

Abstract(1) Wardi, Allen, Turner and Stary (1966) and Margolis (1967) have reported that arabinose is a component of hyaluronic acid from mammalian brain.(2) In the present study, total acidic polysaccharide and hyaluronic acid fractions were isolated from lipid‐extracted and proteolysed bovine brain by precipitation with cetyltri‐methylammonium bromide. These fractions were analysed for arabinose by paper chromatography of deionized hydrolysates and by gas‐liquid chromatography of per(trimethylsilyl)ated methanolysates.(3) Two pentoses, xylose and ribose, were detected. Arabinose was analytically undetectable in both polysaccharide fractions, but was easily detected in a control polysaccharide containing 0‐1% (w/w) arabinose. Arabinose, if present in hyaluronic acid from bovine brain, constitutes less than 0.1 mol per mol of hyaluronic acid (molecular weight 1.5 x 106 daltons).
DNA AND RNA AND THE CYTOARCHITECTURE OF HUMAN FRONTAL CORTEX1
Authors: Hess Helen H. , Thalheimer Caroline 
Published: October 2006

AbstractDNA and RNA were studied in the layers of human prefrontal cortex by quantitative microchemical analyses on microtome‐prepared serial frozen sections. Eleven cortical specimens from six autopsy brains were assayed. The mean total number of cells per mm3 of fresh cortex was estimated from DNA values. The number in layer I (61,000) was falsely high because of the inclusion of cells from the pia mater. From a plateau of 82,000‐86,000 in layers II, IIIa and IIIb, the number of cells rose to 91,000 and 113,000 in layers IIIc and IV, respectively. The mean number was slightly lower in layer V, then gradually rose through layer VI to 127,000 cells in white matter. Per unit dry weight, DNA and cells varied much less than per unit volume; values averaged 14 per cent higher in layers II and IV than in neighbouring layers and in white matter were 20 per cent lower than in layer I.Intracortical patterns of RNA and RNA/cell reflected chiefly the distribution of neuronal cell bodies. Per unit fresh volume, RNA roughly paralleled DNA in layers I‐V; through layer VI and into white matter RNA declined as DNA rose, reflecting the decline in neurons and increasing predominance of glial cells of lower RNA content. Per unit dry weight, RNA rose 50 per cent from layer I to layer II; a plateau of high values extended through layers II‐V, then RNA declined rapidly through layer VI to a level in white matter that was 28 per cent of the value in layer II. Mean RNA/cell in cortex was 9‐8 pg, with a maximum in layer IIIb (11.4 pg); in subcortical white matter it was 5.3 pg.
CEREBRAL PHOSPHOLIPIDS IN ‘QUAKING’ MICE
Authors: Dawson R. M. C. , Clarke N. 
Published: October 2006

AbstractThe brain of the adult ‘quaking’ mutant mouse is characterized by a reduced phospholipid content which can be ascribed not only to the myelin deficiency but also to a well‐defined hydrocephalus. The mutant brain shows highly significant decreases in the percentage of ethanolamine plasmalogen, triphosphoinositide and phosphatidic acid in the whole phospholipid fraction, while the proportions of phosphatidylcholine, phosphatidyl‐ethanolamine, diphosphatidylglycerol and phosphatidylinositol increase. The changes are consistent with the selective absence of ‘myelinic’ phospholipid although phosphatidylserine, sphingomyelin and diphosphoinositide are unchanged.
PARTIAL CHARACTERIZATION OF SOLUBLE ACETYLCHOLINESTERASE ISOENZYMES OF THE RAT BRAIN
Authors: Bajgar J. , ŽIžkovský V. 
Published: October 2006

Abstract(1) The 105,000gsupernatant fluid obtained from rat brain was separated by agar‐gel electrophoresis.(2) Three isoenzymes, capable of hydrolysing acetylthiocholine, one of them also hydrolysing butyrylthiocholine, were detected.(3) The pH optima andKmfor hydrolysis of acetyl‐ and butyrylthiocholine by the supernatant fluid were determined.(4) After extraction of acetylcholinesterase isoenzymes from the gel, individual isoenzymes were characterized by pH optima andKmvalues.(5) Two of the enzymes were characterized as acetylcholinesterase (EC 3.1.1.7) and one as butyrylcholinesterase (EC 3.1.1.8).
EFFECTS OF AMINES ON THE LEVEL OF N‐ACETYL‐ASPARTATE AND N‐ACETYL‐ ASPARTYL‐GLUTAMATE IN MOUSE BRAIN TISSUE SLICES
Authors: Reichelt K. L. , Wedege E. , Kvamme E. 
Published: October 2006

AbstractThe effect of some biogenic amines and amino acids on the level of N‐acetyl‐asparticacid and N‐acetyl‐aspartyl‐glutamic acid has been investigated in mouse brain tissue slices. The amines all caused a significant decrease in the levels of N‐acetyl‐aspartic acid and N‐acetytl‐aspartyl‐glutamic acid within 5 min of incubation, while the amino acids, in spite of being possible transmitter candidates, had no such effect.
THE PREVENTION BY INHIBITORS OF BRAIN PROTEIN SYNTHESIS OF THE HYPERACTIVITY AND HYPERPYREXIA PRODUCED IN RATS BY MONOAMINE OXIDASE INHIBITION AND THE ADMINISTRATION OF L‐TRYPTOPHAN OR 5‐METHOXY‐N,N‐DIMETHYLTRYPTAMINE
Authors: Grahame‐Smitha D. G. 
Published: October 2006

Abstract— In rats treated with a monoamine oxidase inhibitor, (tranylcypromine), L‐ tryptophan produces a stereotyped syndrome of hyperactivity and hyperpyrexia due to an increased rate of brain serotonin (5‐hydroxytryptamine) synthesis. Pretreatment of rats with intraperitoneal injections of cycloheximide, acetoxycycloheximide, emetine and dehydroemetine and of mice with puromycin inhibited this syndrome. Cycloheximide also inhibited the hyperactivity caused by tranylcypromine and DL‐15‐hydroxtryptophan and did not affect the increased rate of brain serotonin ‘synthes’ is produced by tryptophan thus excluding a primary effect on tryptophan‐5‐hydroxylase. Inhibition of hyperactivity did not occur until brain protein synthesis was inhibited by greater than 65 per cent as measured by the incorporation of L‐[U‐14C]tyrosine into brain protein in vivo. Emetine, which has been shown to inhibit brain protein synthesis inhibited hyperactivity whereas isoemetine which did not inhibit brain protein synthesis, did not inhibit hyperactivity.Under conditions where cycloheximide inhibited hyperactivity produced by tranylcypromine and L‐tryptophan, a large dose of 5‐methoxy‐N,N‐dimethyltryptamine(5‐MeODMT) still produced hyperactivity showing that the rats were still capable of the same pattern of hyperactivity. However, cycloheximide did inhibit hyperactivity due to 5‐MeODMT, the degree of this inhibition being dependent upon a balance between the doses of cycloheximide and 5‐MeODMT. 5‐MeODMT probably acts directly within the brain to cause behavioural excitation and it seems likely that the inhibitors of brain protein synthesis interfere with the mechanism of action of brain 5HT and administered 5‐MeODMT rather than upon any aspect of synthesis, storage or release of brain 5HT. It is suggested that the behaviourally excitant effects of brain 5HT and 5‐MeODMT are mediated in some way by a brain protein with a short biological half‐life. Such a protein may act either as a factor specifically mediating the central effects of brain 5HT or as a factor regulating the neuronal response to excitation by 5HT and 5‐MeODMT.
THE ACTION OF CALF BRAIN SIALIDASE ON GANGLIOSIDES, SIALOGLYCOPROTEINS AND SIALOGLYCOPEPTIDES
Authors: Heijlman J. , Roukema P. A. 
Published: October 2006

Abstract— In agreement with other investigators it has been shown that endogenous as well as added gangliosides are a substrate for brain sialidase. The release of sialic acid was enhanced in the presence of Triton X‐100; this might be due to the action of the detergent on the ganglioside micelles. The sialic acid release from endogenous gangliosides was observed over 48 h and compared with the effect of the sialidase on the endogenous glycoproteins. Though the hydrolysis of sialic acid from gangliosides is much faster in the first hours, after 48 h 40 per cent of the total bound sialic was released from both substrates at pH 4.0 and 37°C.Sialoglycopeptides obtained from brain glycoproteins are also metabolized by the sialidase. No effect of Triton X‐100 on this substrate has been observed. From sialoglycopeptides, fractions can be obtained by DEAE‐Sephadex A‐50 column chromatography with a sialic acid content from 8 to 26 per cent. The fractions with a high sialic acid content were about equally active towards brain sialidase as gangliosides. The results agree with the similar turnover rate observed for the carbohydrate chains from gangliosides and glycoproteins, but are in contrast to the observations of other investigators who have stated that glycoproteins are a poor substrate for brain sialidase. In our experiments bovine and ovine submaxillary mucins and sialyl‐lactoses showed only slight activity compared to gangliosides and selected brain sialoglycopeptides.
CITRATE OXIDATION IN THE CYTOPLASMIC FRACTION OF RAT BRAIN
Authors: Gromek A. , Rafałowska Urszula 
Published: October 2006

Abstract— The cytoplasmic fraction derived from rat brain was shown to possess the ability to oxidize citrate in the presence of NADP, but not in that of NAD. The rate of citrate oxidation is limited by the rate of the aconitase‐catalysed isomerization. The dependence of the reaction rate on the protein, citrate and NADP concentrations, and on reaction time, was determined. It was found that 2‐oxoglutarate and NADPH, both formed in the citrate oxidation reaction, do not appear in amounts equivalent to the losses of citrate. The possible ways of utilization of the above products in the rat brain cytoplasmic fraction are discussed.It is suggested that the oxidation of citrate in rat brain cytoplasm may proceed–among other metabolic routes–through its conversion into isocitrate (aconitase) and then 2‐oxoglutarate (NADP dehydrogenase) and oxaloacetate (aspartate aminotransferase). In addition it has been shown that hypoxia may markedly effect the activity of the cytoplasmic citrateoxidizing system.