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  • Electronic Resource  (8)
  • 1995-1999  (8)
  • Chemistry  (6)
  • Extracellular glutamate  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Effect of carbamazepine, oxcarbazepine and lamotrigine on the increase in extracellular glutamate elicited by veratridine in rat cortex and striatum (1996)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 354 (1996), S. 164-172 
    Details
    ISSN: 1432-1912
    Keywords: Key words Microdialysis ; Extracellular glutamate ; Veratridine ; Carbamazepine ; Oxcarbazepine ; Lamotrigine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Lamotrigine, carbamazepine and oxcarbazepine inhibit veratrine-induced neurotransmitter release from rat brain slices in concentrations corresponding to those reached in plasma or brain in experimental animals or humans after anticonvulsant doses, presumably due to their sodium channel blocking properties. Microdialysis measurements of extracellular glutamate and aspartate were carried out in conscious rats in order to investigate whether corresponding effects occur in vivo. Veratridine (10 μM) was applied via the perfusion medium to the cortex and the corpus striatum in the presence of the glutamate uptake inhibitor L-trans-pyrrolidine-2,4-dicarboxylic acid (1 mM in perfusion medium). Maximally effective anticonvulsant doses of carbamazepine (30 mg/kg), oxycarbazepine (60 mg/kg) and lamotrigine (15 mg/kg) were given orally. The uptake inhibitor increased extracellular glutamate and aspartate about 2-fold in striatum and about 7-fold and 3-fold, respectively, in cortex. Veratridine caused a further 2-3-fold increase in extracellular glutamate in striatum and cortex, respectively, but its effect on extracellular aspartate was less marked in both areas. None of the anticonvulsant compounds affected the veratridine-induced increases in extracellular glutamate or aspartate in the striatum which were, however, markedly inhibited by tetrodotoxin (1 μM) and thus are sensitive to sodium channel blockade. In the cortex, the same drugs at the same doses did cause about 50% inhibition of the veratridine-induced increase in extracellular glutamate. Carbamazepine and to a lesser extent lamotrigine, but not oxcarbazepine, also inhibited the veratridine-induced increase in extracellular aspartate in the cortex. Although our results might seem to support the view that inhibition of glutamate and aspartate release is responsible for the anticonvulsant effects of lamotrigine, carbamazepine and oxcarbazepine, two complementary findings argue against this interpretation. First, as previously shown, inhibition of electrically induced release of glutamate requires 5 to 7 times higher concentrations of these compounds than release elicited by veratrine. Second, the present study indicates that doses totally suppressing convulsions caused no inhibition in the striatum and at best a 50% inhibition in the brain cortex. From this we conclude that the doses used here, although to some extent effective against veratridine, did not suppress the release of GLU and ASP elicited by the normal ongoing electrical activity of the glutamatergic and aspartatergic neurons and that the mechanism of the suppression of convulsions must be sought elsewhere.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00178716
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Effect of carbamazepine, oxcarbazepine and lamotrigine on the increase in extracellular glutamate elicited by veratridine in rat cortex and striatum (1996)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 354 (1996), S. 164-172 
    Details
    ISSN: 1432-1912
    Keywords: Microdialysis ; Extracellular glutamate ; Veratridine ; Carbamazepine ; Oxcarbazepine ; Lamotrigine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Lamotrigine, carbamazepine and oxcarbazepine inhibit veratrine-induced neurotransmitter release from rat brain slices in concentrations corresponding to those reached in plasma or brain in experimental animals or humans after anticonvulsant doses, presumably due to their sodium channel blocking properties. Microdialysis measurements of extracellular glutamate and aspartate were carried out in conscious rats in order to investigate whether corresponding effects occur in vivo. Veratridine (10 μM) was applied via the perfusion medium to the cortex and the corpus striatum in the presence of the glutamate uptake inhibitor L-trans-pyrrolidine-2,4-dicarboxylic acid (1 mM in perfusion medium). Maximally effective anticonvulsant doses of carbamazepine (30 mg/kg), oxycarbazepine ( 60 mg/kg) and lamotrigine (15 mg/kg) were given orally. The uptake inhibitor increased extracellular glutamate and aspartate about 2-fold in striatum and about 7-fold and 3-fold, respectively, in cortex. Veratridine caused a further 2–3-fold increase in extracellular glutamate in striatum and cortex, respectively, but its effect on extracellular aspartate was less marked in both areas. None of the anticonvulsant compounds affected the veratridine-induced increases in extracellular glutamate or aspartate in the striatum which were, however, markedly inhibited by tetrodotoxin (1 μM) and thus are sensitive to sodium channel blockade. In the cortex, the same drugs at the same doses did cause about 50% inhibition of the veratridine-induced increase in extracellular glutamate. Carbamazepine and to a lesser extent lamotrigine, but not oxcarbazepine, also inhibited the veratridine-induced increase in extracellular aspartate in the cortex. Although our results might seem to support the view that inhibition of glutamate and aspartate release is responsible for the anticonvulsant effects of lamotrigine, carbamazepine and oxcarbazepine, two complementary findings argue against this interpretation. First, as previously shown, inhibition of electrically induced release of glutamate requires 5 to 7 times higher concentrations of these compounds than release elicited by veratrine. Second, the present study indicates that doses totally suppressing convulsions caused no inhibition in the striatum and at best a 50% inhibition in the brain cortex. From this we conclude that the doses used here, although to some extent effective against veratridine, did not suppress the release of GLU and ASP elicited by the normal ongoing electrical activity of the glutamatergic and aspartatergic neurons and that the mechanism of the suppression of convulsions must be sought elsewhere.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00178716
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Enhanced Resolution of Conjugated Linoleic Acid Isomers by Tandem-Column Silver-Ion High Performance Liquid Chromatography (1999)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 22 (1999), S. 144-148 
    Details
    ISSN: 0935-6304
    Keywords: Conjugated linoleic acid (CLA) ; silver-ion high performance liquid chromatography (Ag+-HPLC) ; cheese ; analysis ; silver-ion chromatography ; tandem-column Ag+-HPLC ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---A commercial mixture of conjugated linoleic acid (CLA) isomers, reportedly consisting of six components, was recently resolved into 12 peaks attributed to CLA isomers using silver-ion high performance liquid chromatography (Ag+-HPLC). In this study, the coupling of two analytical silver-ion high performance liquid chromatography columns (tandem-column Ag+-HPLC) in series led to the enhanced resolution of CLA isomers. Many CLA isomers were baseline resolved and the pair 18 : 2 8,10 c/t and 18 : 2 7,9 c/t found in cheese products, was resolved for the first time. In this work, a similar commercial CLA mixture was separated into 16 peaks, while CLA isomers from cheese also gave rise to 16 peaks. As expected, the CLA isomers were separated into three geometric groups in the order trans,trans, cis/trans, and cis,cis. Semi-preparative Ag+-HPLC, followed by gas chromatography-mass spectroscopy of the dimethyloxazoline derivatives, was used to confirm the identity of the newly resolved positional CLA isomers. The double bond configuration of CLA isomers was established by gas chromatography-Fourier transform infrared spectroscopy. Two minor t,t CLA isomers found in cheese, presumably 18 : 2 t6t8 and 18 : 2 t13t15, were also separated. The CLA isomeric composition of 16 commercial cheese products was determined.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 4
    Electronic Resource
    Electronic Resource
    Synthesis and Anionically Induced Domino Reactions of Chiral α-Bromo α,β-Unsaturated Esters (1998)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1998 (1998), S. 1569-1576 
    Details
    ISSN: 1434-193X
    Keywords: Asymmetric dihydroxylation (Sharpless-AD) ; Wittig olefination ; α-Bromo α,β-unsaturated esters ; Diastereoselective aprotic Michael domino reaction ; Tricyclo[3.2.1.02,7]octanes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The chiral α-bromo α,β-unsaturated esters 3 and 9 are prepared by asymmetric Sharpless dihydroxylation (AD) of 5 and from ester 7 and the chiral diols 8 by transacetalization, respectively. Both types of α-bromo α,β-unsaturated ester react with the kinetic lithium dienolates of enone 10 to give functionalized tricyclo[3.2.1.02,7]octanes 11. Esters 3 give one single diastereomer (de ≥ 95%), whereas mixtures of diastereomers (de 28 to 46%) are obtained with the esters 9.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 5
    Electronic Resource
    Electronic Resource
    Novel polymeric alcohols by controlled catalytic polymer functionalization (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 56 (1995), S. 533-543 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Novel EPDM (ethylenepropylenediene monomer) and polybutadiene polyols can be synthesized by a two-step process of controlled hydroformylation and then reduction of the formyl groups to place a desired amount of pendant alcohol groups along the polymer chain. The degree of functionalization can be controlled by measuring gas uptake from a calibrated reservoir during hydroformylation. Hydroformylation can be performed in solution or under simulated melt-phase conditions using either HRh(CO)(PPh3)3 or Rh(acac) (CO)2 as catalysts. Reduction of the polyaldehyde by NaBH4 generates the polymeric alcohol without further reaction of the remaining double bonds. Polymer functionalization and further modifications were followed by H-NMR and FTIR. These unique hydrophobic polyols can be reacted further to produce other polymer systems. As an example, urethanes have been made with these polyols by reaction with diisocyanates. © 1995 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1995.070560502
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  • 6
    Electronic Resource
    Electronic Resource
    Characterization of the Optical Properties and Composition of TiNx Thin Films by Spectroscopic Ellipsometry and X-ray Photoelectron Spectroscopy (1996)
    Chichester [u.a.] : Wiley-Blackwell
    Surface and Interface Analysis 24 (1996), S. 627-633 
    Details
    ISSN: 0142-2421
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Thin films of TiNx with 0.34〈x〈1.19 were deposited on silicon substrates by a filtered arc deposition process. Spectroscopic ellipsometry (SE) in the energy region 1.5-3.5 eV was used to measure the optical properties of the films. X-ray photoelectron spectroscopy (XPS) was used to determine the relative atomic concentration and the chemical states of the elements. The dielectric function ε(ω) measured by ellipsometry gives the optical response of TiNx films and valuable information on their chemical composition, which is also verified by XPS. The plasma energy ωp of TiNx films was found to depend strongly on the N/Ti ratio and this is correlated with the value of x as determined by XPS and Rutherford backscattering spectroscopy (RBS). The results show that, via the calibration, spectroscopic ellipsometry may be used to estimate the stoichiometry of deposited TiNx films.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 7
    Electronic Resource
    Electronic Resource
    Ein Zinn(II)-phosphat mit einer offenen Gerüst-struktur: [H3N(CH2)2NH3]0.52+ [Sn4P3O12]Diese Arbeit wurde von der National Science Foundation (MRSEC-Programm, DMR 9632716) gefördert. (1997)
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 109 (1997), S. 1013-1015 
    Details
    ISSN: 0044-8249
    Keywords: Mikroporosität ; Offene Gerüststrukturen ; Phosphor ; Strukturbestimmung ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ange.19971090916
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  • 8
    Electronic Resource
    Electronic Resource
    [H3N(CH2)2NH3]0.52+[Sn4P3O12]-: An Open-Framework Tin(II) PhosphateThe work was funded by the MRSEC program of the U. S. National Science Foundation (DMR 9632716). (1997)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 36 (1997), S. 978-980 
    Details
    ISSN: 0570-0833
    Keywords: microporosity ; open-frame structures ; phosphorus ; structure elucidation ; zinc ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.199709781
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