bluuebunny/crossref_metadata_2025_split huggingface dataset:
NUCLEAR PROTEIN PATTERNS IN DEVELOPING AND ADULT BRAIN AND IN ETHYLNITROSOUREA‐INDUCED NEUROECTODERMAL TUMOURS OF THE RAT1,2
Authors: Biessmann H. , Rajewsky M. F. 
Published: October 2006

Abstract—In a comparative study, the patterns of histones and non‐histone proteins were analysed in the chromatin of foetal (18th day of gestation), 10‐day‐old, and adult BD IX‐rat brain, as well as in the chromatin of two ethylnitrosourea‐induced neuroectodermal tumours (TV1A1 and GV1A1) and the corresponding malignant cell culture lines TV1C1 and GV1C1. Separation of nuclear proteins at high resolution was obtained by electrophoresis in 15% and 10% polyacrylamide gels containing urea (2·5 m or 6·25 m). In spite of an overall similarity, significant quantitative and qualitative differences were observed between the respective non‐histone proteins banding patterns of normal brain and the neoplastic cells analysed. The non‐histone protein banding patterns of brain (∼40 different bands) at different stages of development revealed both quantitative differences and the presence of particular bands characteristic of foetal or adult brain, respectively. Both the‘foetal’and‘adult’non‐histone protein bands also appeared in the electrophoretograms of the neoplastic neuroectodermal cells.
DEMONSTRATION D'UNE RELATION INVERSEMENT PROPORTIONNELLE ENTRE LA DOPAMINE ET LA SEROTONINE DANS CERTAINES STRUCTURES CEREBRALES: ASPECTS NEUROCHIMIQUE ET MORPHOLOGIQUE1
Authors: Roberge A. G. , Parent A. , Boulay M. 
Published: October 2006

RésuméeUne diminution significative de la sérotonine dans toutes les structures du cerveau est démontrée chez le chat suìte à un traitement chronique à la p‐chlorophénylalanine (250 mg/kg i.p., 2 doses, à intervalles de 72 h). Les concentrations de noradrenaline ne sont pas affectées par un tel traitement. Par ailleurs, les concentrations de dopamine sont significativement augmentées dans le lobe piriforme, le septum, l'hypothalamus et le mésencéphale et normales dans. le néostriatum, le cortex frontal, le tuberculum olfactorium et le cervelet. Des chats porteurs d'une lésion sélective du noyau raphae dorsalis, sans atteinte des autres noyaux, démontrent une baisse significative de la sérotonine du néostriatum et du lobe piriforme. Comparativement aux chats traités à la p‐chlorophénylalanine, les chats lésés présentent une augmentation significative des concentrations de la dopamine du lobe piriforme alors que cells du néostriatum demeurent normales. Ces résultats permettent de dissocier les structures appartenant au système limbique des structures appartenent au système moteur extrapyramidal à la fois sur une base biochimique et morphologique. De plus, ces données suggèrent que. le rôle physiologique de la dopamine du système moteur extrapyramidal est fonctionnellement différent du rôle de la dopamine impliquée dans les structures du système limbique.AbstractCats treated chronically with p‐chlorophenylalanine (250 mg/kg, i.p., 2 doses, 72 h apart) demonstrate a significant decrease in serotonin concentrations in all structures within the brain. The noradrenaline level was not affected. Dopamine concentrations were however significantly increased in the piriform lobe, septum, hypothalamus and mesencephalon and unchanged in the neostriatum, frontal cortex, tuberculum olfactorium and cerebellum. In cats bearing a selective lesion of nucleus raphae dorsalis without involving other raphae nuclei, a significant decrease in serotonin was observed in the neostriatum and piriform lobe. Compared to p‐chlorophenylalanine treated cats, lesioned cats show a significant increase in dopamine content in the piriform lobe but not in the neostriatum. A single dose of p‐chlorophenylalanine (250 mg,kg, i.p.) as well as a selective lesion of nucleus raphae centralis superior caused a significant decrease in serotonin level without affecting dopamine concentration. Such findings allow differentiation of a group of structures belonging to the limbic system from those of the extrapyramidal motor system on a biochemical as well as on a morphological basis. Moreover these results suggest that dopamine in the nigrostriatal pathway has a different function from dopamine involved in the limbic system.
ISOLATION AND CHARACTERIZATION OF PLASMA MEMBRANES FROM THE ADRENAL MEDULLA1
Authors: Wilson S. P. , Kirshner N. 
Published: October 2006

Abstract– The isolation of a plasma membrane fraction from the bovine adrenal medulla and its characterization are described. The plasma membranes are enriched 13‐fold in AChE, a plasma membrane marker, and represent 0.7% of the homogenate membrane protein. The yield of these membranes is typically 10‐12% by the criterion of the percentage of total membrane bound AChE in the homogenate. The membranes were characterized as to their polypeptide, phospholipid and cholesterol content and compared with chromaffin vesicle, mitochondrial and microsomal membranes by these parameters.Two enzymatic components of the plasma membranes, ATPase and adenylate cyclase, were also studied. Calcium ATPase activity is 2.5‐fold higher than magnesium ATPase activity, appears to be the result of a single enzyme, and is a genuine component of the plasma membranes. The magnesium stimulated activity appears to have at least two enzymatic components, one of which may be identical to the calcium ATPase.Adenylate cyclase is a plasma membrane component, but may not be uniquely localized there, as it is rather unstable throughout the fractionation procedure. It is stimulated by GTP (0.7‐fold at 10−5M), GPP(NH)P (4.8‐fold at 10−5M) and sodium fluoride (4.6‐fold at 10−2M). It is refractory to stimulation by all other compounds tested.
TAURINE AND COBALT INDUCED EPILEPSY IN THE RAT: A BIOCHEMICAL AND ELECTROCORTICOGRAPHIC STUDY
Authors: Joseph M. H. , Emson P. C. 
Published: October 2006

Abstract– The level of taurine around the epileptic focus induced by cobalt‐gelatine pellet implantation into rat brain was found to be reduced at 8‐11 days post‐operation, the time of maximal spike activity in the electrocorticogram. It returned towards normal at later times. This pattern was seen not only in the primary focus, but also to a lesser extent in the secondary focus in the contralateral cortex. Acute administration of taurine intraperitoneally or intraventricularly resulted in at most transient effects on epileptic spiking.Chronic oral taurine elevated brain taurine in normal rats only after prolonged administration, but in cobalt‐treated rats it prevented the fall of taurine in the secondary focus, and reduced the extent and duration of the fall in the primary focus; nonetheless chronic oral or intraventricular administration failed to modify the development of spike activity. At 11 days after implantation, chronic oral taurine did not significantly reverse the falls in transmitter amino acids in the primary focus. It is concluded that taurine is ineffective in altering the development or expression of this type of cobalt‐induced epilepsy in the rat, in spite of adequate penetration to the brain. Possible reasons for the discrepancies with studies by other workers are discussed.
NEUROSECRETORY CELL PROTEIN METABOLISM IN THE LAND SNAIL,OTALA LACTEA
Authors: Loh Y. Peng , Barker J. L. , Gainer H. 
Published: October 2006

Abstract—Protein synthesis in an identified molluscan neurosecretory cell of the land snail, Otala lactea was examined using three different types of polyacrylamide gel electrophoresis. Cells taken from active snails synthesized specific low molecular weight proteins while those from aestivated snails did not. Most of the newly synthesized low molecular weight proteins in the active snails were lost from the cell body when the preparations was chased for 19 h in label‐free enriched medium in the presence of anisomycin, an inhibitor of protein synthesis. If colchicine, a blocker of axonal transport, was included in the chase medium, the proteins present following a pulse were largely replaced by smaller molecular weight species. The results suggest that specific low molecular weight proteins are converted to smaller species and then transported from the cell body.
THE EFFECT OF HIGH CONCENTRATIONS OF HISTIDINE ON THE LEVEL OF OTHER AMINO ACIDS IN PLASMA AND BRAIN OF THE MATURE RAT
Authors: Typfield L. A. , Holton J. B. 
Published: October 2006

Abstract—Changes in plasma and brain amino acids have been observed in adult rats 1 h after intraperitoneal injections of histidine and in others maintained on high histidine diets for 8 days. In the injection studies the compounds most consistently affected were the aromatic and branched chain amino acids and methionine. Reductions in their concentrations in the brain were explained by a competition with histidine for uptake into the tissue. There was little change in plasma amino acid levels. In the animals fed the highest concentration of histidine there was a generalized increase in brain, and a reduction in plasma, amino acid concentrations. A decrease in protein synthesis is postulated to explain this effect in brain.
NEUROBLASTOMA CELL ADENYLATE CYCLASE: DIRECT ACTIVATION BY ADENOSINE AND PROSTAGLANDINS1
Authors: Penit J. , Huot J. , Jard S. 
Published: October 2006

Abstract—Adenylate cyclase activity of permeabilized neuroblastoma cells was measured by the conversion of [α32P]ATP into labelled cyclic AMP. Adenosine (10−6 ‐ 10−4m) induced a dose‐dependent increase in cyclic AMP formation. This effect could not be accounted for either by an adenosine‐induced inhibition of the phosphodiesterase activity present in the enzyme preparation, or by a direct conversion of adenosine into cyclic AMP. This indicates that the observed increase in cyclic AMP accumulation reflected an activation of adenylate cyclase. Adenosine is partially metabolized during the course of incubation with the enzyme preparation. However, none of the identified non‐phosphorylated adenosine metabolites were able to induce an adenylate cyclase activation. This suggests that adenosine itself is the stimulatory agent. The apparent Km of the adenylate cyclase for adenosine was 5 ± 10−6‐10−5m. Maximal activation represented 3‐4 times the basal value (10‐100 pmol cyclic AMP formed/10 min/mg protein). The adenosine effect was stereospecific, since structural analogues of adenosine were inactive. Adenosine increased the maximal velocity of the adenylate cyclase reaction. The stimulatory effect of adenosine was inhibited by theophylline. Prostaglandin PGE1 had a stimulatory effect much more pronounced than that of adenosine (6‐10‐fold the basal value at 10−6m). Dopamine and norepinephrine induced a slight adenylate cyclase activation which was not potentiated by adenosine. It is concluded that adenosine is able to activate directly neuroblastoma cell adenylate cyclase. It seems very likely that such a direct activation is also present in intact nervous tissue and account, at least partly, for the observed cyclic AMP accumulation in response to adenosine.
CHANGES IN ACYL GROUP COMPOSITION OF DIACYL‐GLYCEROPHOSPHORYLETHANOLAMINE, ALKENYLACYL‐GLYCEROPHOSPHORYLETHANOLAMINE AND DIACYL‐GLYCEROPHOSPHORYLCHOLINE IN MYELIN AND MICROSOMAL FRACTIONS OF MOUSE BRAIN DURING DEVELOPMENT
Authors: Sun G. Y. , Yau T. M. 
Published: October 2006

Abstract—Age‐related changes in acyl group composition of diacyl‐glycerophosphorylethanolamine (GPE), alkenylacyl‐GPE and diacyl‐glycerophosphorylcholine (GPC) were examined in myelin and microsomal fractions of mouse brain during development. In general, the phosphoglycerides in the myelin fraction showed an increase in the proportions of 18:1 and 20:1 and a decrease in the proportions of 16:0, 20:4(n‐6) and 22:6(n‐3) with increasing age. These changes were especially obvious with the acyl groups of alkenylacyl‐GPE. The acyl group profiles of phosphoglycerides in the microsomal fraction were different from those in the myelin fraction. During development, there was an increase in 22:6 and a decrease in 20:4 in the phosphoglycerides of microsomes. These changes were especially obvious with the diacyl‐GPE. Starting from 2 weeks of age, there was also an increase in the proportions of 18:1 and 20:1 in alkenylacyl‐GPE in the microsomal fraction but this change was not as dramatic as that in the myelin fraction. In general, the acyl groups of diacyl‐GPC in both myelin and microsomal fractions showed only little age‐related changes as compared to the ethanolamine phosphoglycerides. Results suggest an induction in the synthesis of monoenoic fatty acids in brain during development. The monoenoic fatty acids synthesized during this period are rapidly and preferentially incorporated into the ethanolamine plasmalogen for further utilization in synthesis of the myelin membranes.
RESPONSE OF RAT BRAIN INDOLES AND MOTOR ACTIVITY TO SHORT LIGHT‐DARK CYCLES1
Authors: Hanselma Georgiana , Borbély A. A. 
Published: October 2006

Abstract—Since the vigilance states of the rat can be largely controlled by one hour light‐one hour dark cycles, we investigated the effect of this photoperiod on the rat brain indoles and motor activity. Groups of 9 rats were killed 15‐20 min or 45‐50 min after the onset of the 1‐hour light or 1‐hour dark period. Serotonin (5HT) and 5‐hydroxyindoleacetic acid were determined fluorometrically in cortex, hypothalamus and brain stem. Tryptophan was determined fluorometrically in serum, cortex and hypothalamus. Cortical tryptophan was highest at the end of the dark period, whereas cortical 5‐HT and 5‐hydroxyindoleacetic. acid were highest at the beginning of the light period. Motor activity was high during darkness and low during light.When the biochemical results were compared to the motor activity records of the individual animals, the decrease in motor activity at the onset of light correlated significantly with the cortical 5‐hydroxyin‐ doleacetic acid/5‐HT ratio in the animals killed at the beginning of the light period. The results indicate a rapid response of the cortical indoles to the onset of light and support the hypothesis that the induction of sleep is related to the brain indole metabolism.
UPTAKE OF α‐METHYL‐D‐GLUCOSIDE BY SYNAPTOSOMES FROM RAT BRAIN
Authors: Warfield Anna S. , Segal S. 
Published: October 2006

AbstractInflux of α‐methylglucoside into synaptosomes prepared by differential and Ficoll density gradient centrifugation was studied to determine whether this sugar could be used as a model for glucose transport in nerve endings. The rate of uptake of a‐methylglucoside was linear over a wide range of substrate concentrations. Influx was only slightly inhibited (12–15%) in the presence of glucose, 2‐deoxyglncose, phloretin and 2,4‐dinitrophenol and was unaffected by galactose or phlorizin. Conver‐ sion of a‐methylglucoside to phosphorylated intermediates in synaptosomes was negligible. The data are consislent with the influx of a‐methylglucoside being primarily a diffusion process or being mediated by a system with an extremely high Km. However, it is possible that a small portion of the sugar may be transported by the low affinity glucose transport system. The results indicate that a‐methylgluco‐ side is not a good model for glucose transport in synaptosomes as it is in other tissues.
THE SUBCELLULAR DISTRIBUTION OF CARBONIC ANHYDRASE IN HOMOGENATES OF PERFUSED RAT BRAIN
Authors: Yandrasitz J. R. , Ernst S. A. , Salganicoff L. 
Published: October 2006

Abstract— The distribution of carbonic anhydrase was examined in subcellular fractions of perfused rat brain and compared with those of markers for cytosol (lactic dehydrogenase), mitochondrial matrix (glutamic dehydrogenase), and mitochondrial membranes (succinic dehydrogenase). About half of the total carbonic anhydrase was found in particulate fractions, with the greatest part of this in the crude mitochondrial fraction. This fraction was separated into its components on a discontinuous sucrose gradient either as such or after isotonic mechanical disruption with a French pressure cell, and the resultant fractions were characterized by electron microscopy and by assay of marker enzymes.Carbonic anhydrase was solubilized by mechanical disruption, but not to the same extent as lactic dehydrogenase. The highest specific activity for carbonic anhydrase was found in the myelin fraction of the gradient. A mitochondrial locus for carbonic anhydrase is unlikely, but the presence of the enzyme in synaptosomes remains in question.Addition of soluble carbonic anhydrase did not significantly increase the activity of particulate fractions. Treatment of particulate fractions with detergent was necessary to reveal latent activity; this procedure resulted in a more than ten‐fold increase in the measurable carbonic anhydrase activity of myelin fragments.
DISTRIBUTION AND REGULATION OF CYCLIC NUCLEOTIDE LEVELS IN CEREBELLUM, IN VIVO1
Authors: Rubin E. H. , Ferrendelli J. A. 
Published: October 2006

Abstract— In mouse cerebellum, in vivo. cyclic GMP levels are 7 pmol/mg protein in the vermis and 40% lower in the hemispheres, whereas cyclic AMP levels are 7 9 pmol/mg protein in both regions. In the vermis. most of the cyclic GMP is contained in the molecular layer; cyclic AMP levels are highest in the granular layer. Amphetamine, harmaline. pentylenetetrazol and physical shaking elevate, and diazepam and reserpine depress levels of cyclic GMP in both vermis and hemispheres. Oxotremorine and atropine, respectively, increase and decrease cyclic GMP levels only in vermis. Regardless of the agent used, most of the change (67 89%) in cyclic GMP levels occurs in the molecular layer of the vermis; the remainder occurs in the granular layer. Of the drugs tested, only pentylenetetrazol affects cyclic AMP levels, and this drug increases cyclic AMP levels in both vermis and hemispheres and causes equal elevations in the molecular and granular layers of the vermis. In incubated slices of mouse cerebellum, none of the drugs produces changes in cyclic nucleotide levels which are similar to those in vivo. These data indicate that many drugs and conditions that alter cyclic GMP levels in cerebellum act via a common, but indirect, process.We suggest that cyclic GMP levels in cerebellum are regulated by the activity of both the climbing fiber and mossy fiber cerebellar afferent systems. Increased activity in these afferent pathways causes elevation of cyclic GMP levels in Purkinje cells and perhaps in other cells; decreased activity leads to depressed cyclic GMP levels.
14C‐LABELLED AMINO ACIDS AND GLUCOSE IN RAT BRAIN AND LIVER AFTER INJECTION OF [2‐14C]PROPIONATE
Authors: Gaitonde M. K. , Wharton J. , Holt Elizabeth 
Published: October 2006

Abstract— [2‐14C]Propionate injected into rats was metabolized into [14C]glucose and 14C‐labelled aspartate, glutamate, glutamine and alanine. The results are consistent with the conversion of propionate into succinate and the oxidation of succinate into oxaloacetate, the precursor of labelled amino acids and the substrate for gluconeogenesis.The ratio of the specific radioactivity of glutamine to glutamate was greater than 1 during the 30 min period in the brain, indicating that propionate taken up by the brain was metabolized mainly in the ‘small glutamate compartment’ in the brain. The results, therefore, support the previous conclusion (Gaitonde, 1975) that the labelling of amino acids by [14C]propionate formed from [U‐14C>]‐threonine in thiamin‐deficient rats was metabolized in the ‘large glutamate compartment’ of the brain.The specific radioactivity ratio of glutamine to glutamate in the liver was less than 1 during the 10 min period but greater than 1 at 30min. These findings which gave evidence against metabolic compartments of glutamate in the liver, were interpreted as indicative of the entry of blood‐borne [14C]glutamine synthesized in other tissues, e.g. brain. The labelling of amino acids when compared to that after injection of [U‐14C]glucose showed that [2‐14C]propionate was quantitatively a better source of amino acids in the liver. The concentration of some amino acids in the brain and liver was less in the adult than in the young rats, except for alanine and glutathione, where the liver content was more than double that in the adult.
THE MAJOR SITE OF GUINEA‐PIG MYELIN BASIC PROTEIN ENCEPHALITOGENIC IN LEWIS RATS12
Authors: Chou C.‐H. J. , Chou F. C.‐H. , Kowalski T. J. , Shapira R. , Kibler R. F. 
Published: October 2006

Abstract—In the Lewis rat, fragment 43–88 of the highly encephalitogenic guinea‐pig basic protein has been previously shown to retain the full activity of the parent protein. In the present studies this fragment was subjected to controlled chymotryptic digestion so that cleavage occurred only at tyrosine 67, generating two peptides, residues 43‐67 and residues 68‐88. When compared on an equimolar basis peptide 68‐88 had the same encephalitogenic activity as the intact fragment and induced the same degree of immunologically specific cell response as measured by the in vitro lymphocyte stimulation test. Peptide 68‐88 was further fragmented by selective tryptic cleavage at arginine 78 after blocking lysine 73 with citraconic anhydride. The two peptides, residues 68‐78 and residues 79‐88, were not encephalitogenic, indicating that residues adjacent to the point of cleavage contribute to the active site.
BRAIN CONCENTRATIONS OF BIOGENIC AMINES AND THEIR METABOLITES IN TWO TYPES OF PYROGEN‐INDUCED FEVER IN RABBITS
Authors: Gardey‐Levassort Christiane , Tanguy Odette , Lechat P. 
Published: October 2006

Abstract—The effects of two bacterial pyrogens (gonococcus vaccine and E. coli lipopolysaccharide) on brain and CSF concentrations of the biogenic amines and their major metabolites were compared in rabbits. Both pyrogens induced a similar fever, but only the lipopolysaccharide elicited marked biochemical alterations. The main changes observed were: a decrease in the concentrations of acid metabolites of dopamine during the upward course of the first peak of fever; a decrease in the hypothalamic concentrations of noradrenaline at the second peak of fever; a general increase in the metabolites of biogenic amines around the second peak and during the fall of fever. The results led to the conclusion that no significant correlation exists between body temperature and brain amine levels in rabbits. The alterations observed could be a consequence of the fever itself when considered in terms of trauma to the organism.
STUDIES ON THE MECHANISM OF DEMYELINATION: MYELIN AUTOLYSIS IN NORMAL AND EDEMATOUS CNS TISSUE
Authors: SMITH MARION EDMONDS 
Published: October 2006

Abstract—The effects on myelin of autolysis in situ after death and after purification were studied in normal brains and spinal cords and in those made edematous as a result of chronic triethyl tin (TET) feeding. Myelin prepared from normal and edematous brains and spinal cords autolyzed for 12 h at 4°C contained only slightly less basic protein than that prepared from freshly killed animals. The amounts of a light lipid‐protein fraction (dissociated myelin) usually obtained during purification of myelin from edematous CNS were about the same in tissue from freshly killed rats and those autolyzed for 12 h at 4°C. Autolysis for 12 h at room temperature resulted in formation of large amounts of dissociated myelin and loss of basic protein, but more dissociation and basic protein loss occurred in CNS from edematous brains and spinal cords than from the normal. Purified myelin prepared from freshly‐killed normal and TET‐fed rats was incubated at 37°C in media of several ionic strengths. In Krebs‐Ringer bicarbonate (physiological extracellular fluid) extensive dissociation of myelin occurred with much less in 0.04 M‐Tris buffer, pH 7.2, and only small amounts were formed in 0.01 M‐Tris. In all cases myelin from edematous CNS formed more dissociated fraction than did the normal myelin. Basic protein loss was also proportional to the ionic strength of the media, but there was no difference in loss between normal and TET‐myelin. Two different factors, proteolysis and physical extraction of basic protein by salt solutions, may be contributing to myelin dissociation and loss of basic protein.