bluuebunny/crossref_metadata_2025_split huggingface dataset:
AMINO‐ AND CARBOXYL‐TERMINAL AMINO ACIDS OF PROTEOLIPID PROTEINS1
Authors: Whikehart D. R. , Lees Marjorie B. 
Published: October 2006

AbstractThe amino‐ and carboxyl‐terminal amino acids of proteolipids from neural and non‐neural sources were investigated. Amino‐terminal amino acids were identified and quantitated by the dansyiation procedure. Carboxyl‐terminal amino acids were determined after hydrazinolysis or enzymatic hydrolysis with carboxypeptidases. Proteolipid from white matter showed two terminal amino acids, regardless of the method of preparation. The major N‐terminal amino acid was glycine and the minor one was glutamic acid or glutamine. The corresponding C‐terminal amino acids were phenylalanine and glycine. Preparations of white matter proteolipid, therefore, contained more than one protein or protein chain. Proteolipids from brain mitochondria, heart, liver and kidney were characterized by N‐terminal aspartic acid or asparagine and C‐terminal lysine residues and they exhibited an amino acid composition which differed from white matter proteolipid. Our results suggest the existence of two classes of proteolipids, a myelin type and a non‐myelin type. Synaptic membrane and grey matter proteolipids exhibited characteristics of both classes.
AN IMPROVED SULPHUR ASSAY APPLIED TO A PROBLEM OF ISETHIONATE METABOLISM IN SQUID AXON AND OTHER NERVES1
Authors: Hoskin F. C. G. , Brande M. 
Published: October 2006

AbstractAn assay has ken developed for total sulphur which is based on a wet oxidation and measurement with a spectrophotofluorometer of light scattering by barium sulphate. The method has been adapted to the measurement of isethionate in squid nerve and blood, in other cephalopod nerve, and in the nerve tissue of other species including mammals. A correlation has been found between isethionate contents and the activity in the same tissues of one kind of DFP‐hydrolysing enzyme, the highest levels of both being in squid nerve. Squid nerve also took up cysteine rapidly and metabolized it predominantly to hypotaurine but not to isethionate. We speculate that a hypotaurine derivative is a reserve form of isethionate, and that the so‐called DFPase is involved in the release of hypotaurine and its metabolism to isethionate as needed.
INCORPORATION OF 14C FROM [U‐14C]GLUCOSE INTO FREE AMINO ACIDS IN MOUSE BRAIN LOCI IN VIVO UNDER NORMAL CONDITIONS
Authors: Shimada M. , Kihara T. , Kurimoto K. , Watanabe M. 
Published: October 2006

AbstractBy macroautoradiography and by GLC separation, differences in the uptake of radioactive carbon from [U‐14C]glucose into free amino acids (glutamate + glutamine, aspartate + asparagine, GABA, alanine and glycine) in mouse cerebral neocortex, hippocampus, thalamus and hypothalamus were investigated.(1) The autoradiographical densities in the thalamus, cerebral neocortex and hippocampus measured with a microdensitometer were higher than that in the hypothalamus at 5 min after subcutaneous injection. At 180 min, densities in the cerebral neocortex, hippocampus and hypothalamus were higher than that in thalamus.(2) The free amino acid levels determined by GLC varied with each brain region.(3) The specific radioactivity (d.p.m./μmol) of alanine in each brain region was higher than that of the other amino acids at 5 min after the injection. The specific radioactivity of GABA in the brain regions was clearly higher than that of (glutamate + glutamine), (aspartate + asparagine) and glycine at 5 and 15 min.(4) The autoradiographical data were in good agreement with the chemical data at 5 min but were different at 180 min.(5) Variations in specific radioactivity of each free amino acid among brain regions at 5 min were influenced greatly by existing free amino acid concentrations in each region.
Aromatic amino acid transaminases in rat brain
Authors: Minatogawa Y. , Noguchi T. , Kido R. 
Published: October 2006

The Transamination of aromatic amino acids in brain is of interest due to its involvement in the biosynthesis of catechol and indole amines. Previous reports have established the presence of aromatic amino acid transaminases in brain (Canellakis and Cohen, 1962; Albers, Koval and Jakoby. 1962; Haavaldsen, 1962).It was subsequently reported that rat brain extracts contain at least three aromatic amino acid transaminases (Transaminase‐I, II and III) (Fosnum, Haavaldsen and Tangen, 1964; Tangen, Fowum and Haavaldsen, 1965: Fohwum and Larsen, 1965): Transaminase‐I had a high affinity for DOPA, Transaminase‐II an affinity for phenylalanine and tyrosine, and Transaminase‐III an affinity for tryptophan and 5‐HTP. The preferred aminoacceptor of these enzymes was 2‐oxoglutarate or oxaloacetate.The present paper describes the aromatic amino acid transaminases in an extract of rat brain, which differ from the three transaminases described by Tangenet al. (1965).
THE OCCURRENCE OF A GLYCINE CLEAVAGE SYSTEM IN MAMMALIAN BRAIN1
Authors: Bruin W. J. , Frantz B. May , Sallach H. J. 
Published: October 2006

AbstractA major catabolic route for glycine in liver is its conversion to methylene tetra‐hydrofolate (methylene THF), CO2 and NH3, catalysed by the glycine cleavage system described by Yoshida and Kikuchi (1970). In view of the role of glycine as a putative neuro‐transmitter, the occurrence of this system in mammalian brain was investigated. Our studies demonstrated: (a) that the production of 14CO2 from [1‐14C]glycine required the presence of tetrahydrofolate, NAD, dithiothreitol and pyridoxal phosphate in the reaction mixture; (b) that besides CO2l‐serine was the other major product of the reaction; (c) that glyoxylate did not function as an intermediate in this reaction; and (d) that enzymatic activity appeared to be associated with membranes. All of these properties resembled those previously described for the hepatic system.
A COMPARISON OF THE NEURAL REGULATION OF TYROSINE HYDROXYLASE ACTIVITY IN SYMPATHETIc GANGLIA OF ADULT MICE AND RATS
Authors: Heendry I. A. , Iversen L. L. , Black I. B. 
Published: October 2006

AbstractSurgical decentralization of the superior cervical ganglion (SCG) in rats and mice led to a fall in ganglionic tyrosine hydroxylase (T‐OH) activity, and a loss of more than 90 per cent of the preganglionic neurone marker, choline acetyl transferase. T‐OH activity was reduced by more than 50 per cent in mice SCG ten days after surgery, but fell by only 25 per cent in rat SCG after 21 days. The surgical procedure did not cause obvious histo‐logical damage or loss of SCG cells in either species. Both T‐OH and choline acetyl transferase activities in rat and mouse SCG recovered to normal three months after surgery. Reserpine treatment was more effective in rats in causing increased ganglionic T‐OH activity than in mice. Neither decentralization nor reserpine treatment caused any changes in DOPA‐decarboxylase or monoamine oxidase activities in rat SCG. These results demonstrate that T‐OH activity in SCG is subject to trans‐synaptic regulation in both rats and mice; this regulation does not apply to DOPA‐decarboxylase or monoamine oxidase. Differences in basal sympathetic tone may explain the different results obtained in mice and rats.
TYROSINE–ALPHA‐KETOGLUTARATE AMINOTRANSFERASE ACTIVITY IN RAT LIVER AFTER SPINAL CORD SECTION
Authors: Vaptzarova K. I. , Popov P. G. , Galabov G. P. 
Published: October 2006

AbstractSpinal cord section brings about early and late changes in rat liver tyrosine‐alpha‐ketoglutarate aminotransferase activity. Early effects (4 h after surgery): spinal cord section at C7 level causes an unreactiveness of rat liver tyrosine‐alpha‐ketoglutarate aminotransferase both to endogenously and exogenously elevated plasma glucocorticoid levels. Induction of tyrosine–alpha‐ketoglutarate aminotransferase by hydrocortisone administration is almost completely inhibited. This unreactiveness of the rat liver enzyme to hydrocortisone is not due to delayed resorption of hydrocortisone by the peritoneum as tested with [3H]hydrocortisone, to changes in the secretion of hypophyseal hormones or to changes in the levels of glucose in blood or liver. L3 level section of the spinal cord or sham operation results in a stress‐like enzyme pattern (an increase at 4 h with return to normal level at 24 h). The stress elevation of tyrosine–alpha‐ketoglutarate aminotransferase at 4 h after the operation is absent in C7 level sectioned rats. This effect is not due to a decreased plasma corticosterone level since it is 4.1‐fold higher in C7 level sectioned rats and 2.7‐fold higher in sham‐operated controls (as measured 2.5 h after the operation).Late effects (24 h after the surgery): C7 level section of the spinal cord brings about a nine‐fold increase in a tyrosine–alpha‐ketoglutarate aminotransferase activity in animals with intact adrenals and three‐fold increase in adrenalectomized rats at 24 h after the operation. This increase is abolished almost completely by cycloheximide, irrespective of the time of administration. Experiments with actinomycin D, injected at different times after C7 level section have shown that there exists a period of higher sensitivity of the amino‐transferase toward the antibiotic (lasting about 3 h), followed by a period of lower sensitivity (lasting 16 h or longer). These results can be explained by assuming the existence of two tyrosine‐alpha‐ketoglutarate aminotransferase mRNAs with different lifetime. A direct participation of the CNS in the changes in enzymic activity observed after section of the spinal cord above the segments innervating the liver is suggested.
ARYLSULPHATASES IN HUMAN BRAIN: PURIFICATION AND CHARACTERIZATION OF AN INSOLUBLE ARYLSULPHATASE1
Authors: Perumal A. S. , Robins E. 
Published: October 2006

AbstractAfter solubilization with 0.5% (w/v) lysolecithin an arylsulphatase was purified 30‐fold from human brain. By this procedure, 82% of the activity was recovered in the 100,000 g supernatant fluid. Solubilization of the enyzme was dependent on lysolecithin concentration but not on the time of incubation. The enzyme was purified using ethanol and ammonium sulphate fractionations. The purified protein showed a single band on acrylamide gel electrophoresis in two different buffer systems. On ultracentrifugation, a sharp symmetrical peak was obtained with a s20,w value of 5.4 and an apparent molecular weight of 103,000 daltons was calculated. A molecular weight of 105,000 daltons was obtained by sucrose density gradient. Sodium dodecyl sulphate‐polyacrylamide gel electrophoresis showed the presence of two subunit species with molecular weights of 47,000 and 25,000 daltons. The enzyme was unstable at 04°C but could be stored in a frozen state without much loss of activity. 4‐Methylumbelliferone‐sulphate was used as substrate in these studies and the product, methylumbelliferone, was quantified fluorometrically. The enzyme had an optimum pH of 6.8. A higher activity was exhibited in imidazole buffer than in acetate buffer. Enzyme activity was linear up to 30 min of incubation. The enzyme showed a Km of 37.7 μm for 4‐methylumbelliferone‐sulphate. Ammonium sulphate at 5 mm produced a slight activation of the enzyme. Borate, silver and sulphite ions inhibited enzyme activity, whereas p‐chloromercuribenzoate, and cyanide, arsenite, fluoride and phosphate ions caused very little inhibition. The chemical enzymatic hydrolysis of the native enzyme revealed the presence of 2 mol of sialic acid per mole of the enzyme. Enzymatic removal of sialic acid did not affect the activity of the enzyme; therefore, the sialic acid moiety was not required for enzyme activity.
IMMUNOCHEMICAL AND IMMUNOFLUORESCENCE STUDIES OF BETA‐TRACE PROTEIN IN DIFFERENT SPECIES AND ORGANS, WITH SPECIAL REFERENCE TO THE CENTRAL NERVOUS SYSTEM
Authors: Olsson J.‐E. , Nord L. 
Published: October 2006

Abstract—The localization of beta‐trace protein in different human organs and in the brains of other mammals has been investigated with immunochemical and immunofluorescence methods. With the double immunodiffusion technique, the immunological identity between beta‐trace protein in human CSF, brain, femoral nerve, testis, epididymis, spermatic cord, ovary and fallopian tube and in monkey brain could be demonstrated. By means of single radial immunodiffusion on agar, the highest concentrations of beta‐trace protein were found in preparations of water‐soluble proteins of brain and genital organs, especially in white CNS matter, testis and epididymis. With the indirect immunofluorescence technique, bright fluorescence was found in CNS, especially in white matter, and in the stroma of epididymis. The content of beta‐trace protein in femoral nerve was found to be considerably lower than that in the CNS. The results indicate a connexion between beta‐trace protein and the CNS, probably in the myelin or glial cells, and also between beta‐trace protein and the genital system, possibly to cells involved in steroid metabolism. A specificity for highly developed mammals, i.e. man and monkey, is proposed for beta‐trace protein, as no precipitation could be found when brain extracts from calves, rabbits or mice were incubated with anti‐serum against human beta‐trace protein.
EFFECT OF STRESS ON THE UPTAKE OF RADIOLABELLED CALCIUM IN THE PITUITARY GLAND AND THE BRAIN OF THE RAT
Authors: Sabbot Irene , Costin Anatol 
Published: October 2006

AbstractThe in vivo uptake of 45Ca by certain areas of the rat brain and by the pituitary gland was investigated under normal conditions and in states of cold stress. The uptake of 45Ca was highest in the pituitary gland followed in decreasing order by the superior colliculus, medulla, cerebellum, thalamus, hippocampus and the cortex. Cold stress conditions induced an increase in uptake of 45Ca in the cortex, hippocampus, cerebellum, medulla and the pituitary gland. Our findings suggest that cold stress induces a change in the permeability for calcium in blood‐brain and blood‐pituitary barriers.
SERUM TRYPTOPHAN BINDING IN CHLORPROMAZINE‐TREATED CHRONIC SCHIZOPHRENICS
Authors: Bender D. A. , Bamji A. N. 
Published: October 2006

AbstractIn ten hospitalized chronic schizophrenics receiving large doses of chlorpromazine and orphenadrine, the total serum tryptophan was approx. 50 per cent of normal. However, the level of diffusible tryptophan (that fraction directly available for uptake into the brain and other tissues) did not suffer so great a reduction, because the number of sites available for tryptophan binding per mole of serum albumin was only half that normally found, although the apparent affinity of the albumin for tryptophan was approximately normal. There was thus a considerable difference in the ratio of diffusible/bound serum tryptophan between the normal and schizophrenic subjects. Reduced serum albumin and elevated serum non‐esterified fatty acid levels in the schizophrenics do not appear to account for the abnormality of binding. In vitro and animal experiments with the two drugs chlorpromazine and orphenadrine suggested that the effects observed were not due to the drugs per se.
NORADRENALINE IN THE GUINEA PIG ALIMENTARY CANAL: REGIONAL DISTRIBUTION AND SENSITIVITY TO DENERVATION AND RESERPINE
Authors: Juorio A. V. , Gabella G. 
Published: October 2006

AbstractThe concentrations of noradrenaline, dopamine and 5‐hydroxytryptamine were studied in the stomach, duodenum, ileum, caecum (taenia coli), colon and rectum of the guinea pig. The wall of the alimentary canal was dissected into two fractions, one formed by the longitudinal muscle and myenteric plexus, the other formed by circular muscle, submucous plexus, submucosa and mucosa. In the longitudinal muscle‐myenteric plexus, the amount of noradrenaline was lower in the ileum (0.56 μg/g of fresh tissue), higher in the duodenum and caecum (0.75 μg/g and 0.82 μg/g respectively) and even higher in the stomach and rectum (0.85 μg/g and 0.91 μg/g). The highest value was found in the colon (1.33 μg/g), probably related to the occurrence of intramural adrenergic neurons.When extrinsic nerves to the ileum were damaged, the amount of noradrenaline in the corresponding ileal segment was reduced to less than 5 per cent within 3 days in both fractions of the wall. 6‐Hydroxydopamine (35 mg/kg intravenously) reduced to approx. one‐third the amount of noradrenaline in longitudinal muscle‐myenteric plexus of ileum and colon. Reserpine (1 mg/kg, subcutaneously injected 72 h‐earlier) reduced the amount of noradrenaline in the longitudinal muscle‐myenteric plexus of both ileum and colon to 0.01 μg/g. Doses of reserpine as small as 0.02 mg/kg were still effective in causing a great reduction in noradrenaline concentration. No difference in the effects on ileum and colon was observed.
GLYCOSYL TRANSFERASE ACTIVITY IN NORMAL AND SCRAPIE‐AFFECTED MOUSE BRAIN
Authors: Suckling A. J. , Hunter G. D. 
Published: October 2006

Abstract—The conditions required for the optimal activity of several glycosyl transferases were determined in normal and scrapie‐affected mouse brain. Particulate preparations were analysed for fucosyl, galactosyl, mannosyl and N‐acetyl glucosaminyl transferase activity using endogenous acceptors. Solubilized preparations were analysed for fucosyl, galactosyl and sialyl transferase activity using defined exogenous acceptors. The activity of each of these enzymes was followed at intervals throughout the development of scrapie in the mouse. In the endogenous system no change was found in the fucosyl and mannosyl transferase activities of the scrapie material, but the levels of galactosyl and N‐acetyl glucosaminyl transferase began to rise as clinical signs of scrapie developed i.e. at 15–16 weeks post‐inoculation. In the exogenous system the levels of galactosyl and fucosyl transferase began to rise in the scrapie material at 11–12 weeks post‐inoculation, rising to twice the normal value at 18–20 weeks. Sialyl transferase showed no change in activity.
ANTIGEN‐ANTIBODY CROSSED ELECTROPHORESIS OF RAT BRAIN SYNAPTOSOMES AND SYNAPTIC VESICLES: CORRELATION TO WATER‐SOLUBLE ANTIGENS FROM RAT BRAIN
Authors: Bock Elisabeth , Josrgensen O. S. , Morris S. J. 
Published: October 2006

Abstract—Antigen‐antibody crossed electrophoresis has been applied to the study of rat brain synaptosomes and synaptic vesicles. Several antigens could be visualized. By comparison with previously describéd water‐soluble antigens from rat brain, some of the antigens in the synaptosome and the synaptic vesicle preparations were identified; among these were antigens which have been determined as brain‐specific. Furthermore, the antisera against the two subcellular fractions were compared with the anti‐serum against water‐soluble antigens from rat brain.
BIOSYNTHESIS OF FREE AMINO ACIDS IN THE BRAIN OF JIMPY MICE
Authors: Simler S. , Owsianowski N. , Randrianarisoa H. , Ledig M. , Mandel P. 
Published: October 2006

Abstract—The metabolism of free amino acids: γ‐aminobutyric acid (GABA), glutamine, glycine and glutathione has been studied. The labelling of these free amino acids in normal and in myelin‐deficient brains of Jimpy mice was followed after intraperitoneal injection of 14C‐labelled glucose precursor. The quantitative distribution of these amino acids in the two kinds of mouse brain has been compared. A higher level of GABA and a faster labelling of the amino acids in Jimpy than in normal mouse brain was observed.
APPEARANCE OF GAMMA AMINOBUTYRATE TRANSAMINASE ACTIVITY IN DEVELOPING RAT BRAIN
Authors: Hyde J. C. , Robinson N. 
Published: October 2006

Abstract—The distribution, localization and changes in intensity of γ‐aminobutyrate transaminase (4‐aminobutyrate: 2‐oxoglutarate aminotransferase, EC 2.6.1.19) in rat brain have been studied during the first 20 days of postnatal life by a histochemical technique.Enzyme activity at birth was seen only in Purkinje cells of the cerebellar cortex where it increased markedly during the first 20 days. A rapid increase in enzyme activity was seen in regions of the hind‐brain after 3 days but a slower increase was apparent in areas of the fore‐ and mid‐brain. The results indicated that by 10 days post‐partum nerve cell GABA‐T activity had developed in the majority of brain areas studied, while glial cell GABA‐T activity developed between 10 and 15 days post‐partum.Evidence is presented which indicates that there is a discontinuous function of GABA‐T in the developing brain.
CHRONIC LYSERGIC ACID DIETHYLAMIDE ADMINISTRATION AND SEROTONIN TURNOVER IN VARIOUS REGIONS OF RAT BRAIN
Authors: Peters D. A. V. 
Published: October 2006

Abstract—Acute injections of LSD (2 × 500 μg/kg) to rats resulted in evidence of a reduced 5‐hydroxytryptamine (5‐HT) turnover in all brain areas studied. In contrast, a much smaller dose of LSD (20 μg/kg) repeated daily for 1 month produced a significantly reduced turnover only in the midbrain area. The pons/medulla and forebrain areas showed small and not statistically significant increases in 5‐HT turnover.
SULPHATIDE SYNTHESIS IN ISOLATED OLIGODENDROGLIAL AND NEURONAL CELLS12
Authors: Benjamins J. A. , Guarnieri M. , Miller K. , Sonneborn M. , McKhann G. M. 
Published: October 2006

Abstract—Cerebroside sulphotransferase activity in oligodendroglia from calf brain is 8‐fold greater per cell than in calf neurons isolated at the same time under similar conditions. However, neuronal cell fractions from calf or rat brain have significant sulphotransferase activity, and in neurons isolated from rat brain at various ages, the capacity to synthesize sulphatide increases during myelination. The neuronal and oligodendroglial enzymes have similar substrate specificities and pH optima. Less of the enzyme could be extracted with Triton X‐100 from the isolated cells than from microsomes prepared from whole brain.
UPTAKE AND RELEASE OF POSSIBLE FALSE TRANSMITTER AMINO ACIDS BY RAT BRAIN TISSUE1
Authors: Baldessarini R. J. , Yorke C. 
Published: October 2006

Abstract—The uptake of l[14C]glutamine by a crude isolated nerve ending fraction of rat brain was found to be linear with time for at least 5 min, profoundly temperature‐dependent, apparently half‐saturated at a substrate concentration of 0·26 mm, partially inhibited by dinitrophenol and ouabain and elevated [K+], weakly Na+‐dependent, poorly inhibited by drugs which block uptake of biogenic amines and more strongly inhibited by glutamic acid (IC50= 0·5mm) than by aspartic acid, GABA, glycine or methionine. The [14C]glutamine taken up appeared to be associated with nerve endings and was released by membrane‐disruption; about 20 per cent was associated with free mitochondria. Glutamine, δ‐aminolevulinic acid and several other amino acids were poor inhibitors of [3H]GABA‐uptake; δ‐aminolevulinic acid was a poor inhibitor of [3H]glutamine‐uptake, whereas glutamine was a moderately effective competitive inhibitor (Ki= 1 mm). [14C]glutamine and [3H]GABA were released from brain slices by electrical stimulation or 50 mm K+, while labeled δ‐aminolevulinic acid, leucine, urea, amphetamine and tyramine were poorly released. [14C]glutamine was not released by unlabeled glutamate or several aromatic amines. We conclude that the neuropsychiatric features of porphyria are not likely due to a ‘false transmitter’ role for δ‐aminolevulinic acid although such a role for glutamine in hepatic encephalopathy or other neuropsychiatric diseases should be considered.