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  • 1
    Electronic Resource
    Electronic Resource
    Attenuation of Enkephalin Activity in Neuroblastoma × Glioma NG108—15 Hybrid Cells by Phospholipases (1983)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 40 (1983), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: The role of membrane phospholipids in enkephalin receptor-mediated inhibition of adenylate cyclase (EC 4.6.1.1) activity in neuroblastoma × glioma NG108-15 hybrids was studied by selective hydrolysis of lipids with phospholipases. When NG108-15 cells were treated with phospholipase C from Clostridium welchii at 37°C, an enzyme concentration-dependent decrease in adenylate cyclase activity was observed. The basal and prostaglandin E1 (PGE1)-stimulated adenylate cyclase activities were more sensitive to phospholipase C (EC 3.1.4.3) treatment than were the NaF-5′-guanylyl-imidodiphosphate (Gpp(NH)p)-sensitive adenylate cyclase activities. Further, Leu5-enkephalin inhibition of basal or PGE1-stimulated adenylate cyclase activity was attenuated by phospholipase C treatment, characterized by a decrease of enkephalin potency and of maximal inhibitory level. [3H]d-Ala2-Met5-enkephalinamide binding revealed a decrease in receptor affinity with no measurable reduction in number of binding sites after phospholipase C treatment. Although opiate receptor was still under the regulation of guanine nucleotide after phospholipase C treatment, adenylate cyclase activity was more sensitive to the stimulation of Gpp(NH)p. Thus, the reduction of opiate agonist affinity was not due to the uncoupling of opiate receptor from N-component. Further, treatment of NG108-15 hybrid cell membrane with phospholipase C at 24°C produced analogous attenuation of enkephalin potency and efficacy without alteration in receptor binding. The reduction in enkephalin potency could be reversed by treating NG108-15 membrane with phosphatidylcholine, but not with phosphatidylserine, phosphatidylinositol, or cerebroside sulfate. The enkephalin activity in NG108-15 cells was not altered by treating the cells with phospholipase A2 or phospholipase C from Bacillus cereus. Hence, apparently, there was a specific lipid dependency in enkephalin inhibition of adenylate cyclase activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-4159.1983.tb12681.x
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  • 2
    Electronic Resource
    Electronic Resource
    Demonstration and Characterization of Opiate Inhibition of the Striatal Adenylate Cyclase (1981)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 36 (1981), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: The conditions in which Leu5-enkephalin inhibition of striatal adenylate cyclase was observed were defined. It was determined that enkephalin inhibition was dependent on GTP. The apparent Km for GTP in opiate inhibition was determined to be 0.5 and 2 μM when 0.1 mM- and 0.5 mM-ATP were used as substrate. ITP, but not CTP or UTP, could substitute for GTP in the reaction. Though the addition of monovalent cations—Na+,K+, Li+, Cs+, and choline+—stimulated striatal adenylate cyclase activity, enkephalin inhibition of striatal adenylate cyclase did not require Na+ when theophylline was used as the phosphodiesterase inhibitor. Under optimal conditions, i.e., 20 μM-GTP and 100 mM-Na+, Leu5-enkephalin inhibited the striatal adenylate cyclase activity by 23–27%. When the enkephalin regulation of the cyclase activity was further characterized, it was observed that Leu5-enkephalin inhibited the rate of the enzymatic reaction. Kinetic analysis revealed that the opioid peptide decreases Vmax values but not the Km values for the substrates Mg2+ and Mg-ATP. Agents such as MnCl2, NaF, and guanyl-5′-ylimido-diphosphate, which directly activated the adenylate cyclase, antagonized the opiate inhibition. Levorphanol and (–)naloxone were more potent than dextrorphan and (+)naloxone in inhibiting adenylate cyclase and in reversing the enkephalin inhibition, respectively. There were differences in the potencies of various opiate peptides in their inhibition of striatal adenylate cyclase activity, with Met5- 〉 Leu5-enkephalin 〉 β-endorphin. The opiate receptor through which the enkephalin inhibition was observed is most likely δ in nature, since in the presence of either Na+ or K+, the magnitude of the alkaloid inhibition was reduced, whereas the peptide inhibition was either potentiated or not affected.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-4159.1981.tb00438.x
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  • 3
    Electronic Resource
    Electronic Resource
    Immobilization of stationary liquids on silica particles by γ-radiation (1984)
    Springer
    Chromatographia 18 (1984), S. 265-274 
    Details
    ISSN: 1612-1112
    Keywords: New reversed stationary LG-phases ; Crosslinking of oligomers by γ-radiation ; Shielding of silanol-groups ; Surface deactivation ; Characterization methods
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Continuing our work on new silanization reagents for producing chemically-modified small-particle, silica support material exhibiting improved chromatographic performance and especially good shielding of silanol groups in respect of solute-stationary phase interaction, we have developed new silica-based polymer phases with different “polarities” by crosslinking or polymerization reactions induced by γ-radiation. Polybutadienes or polysiloxanes were immobilized on non-, or specially presilanized, 5μm silica particles by using different dose-rates of γ-radiation and by addition of different amounts of allylmethacrylate as a radical stabilizer. The materials obtained were tested by elemental analysis, scanning electron microscopy, ESCA and IR-reflexion measurements as well as by chemical Si−OH determinations. Chromatographic testing has been carried out with different, especially strongly basic solutes, under normal and reversed phase conditions. The dual retention mechanism model of Nahum and Horvath [1] was applied to the usual commercially available phases and those phases produced by ourselves. The influences of mobile phase additives such as acetonitrile or tetrahydrofuran were also investigated following the chromatographic test procedures for characterization of the support materials synthesized. The silicas obtained show excellent long term stability to all types of HPLC solvents. Their inertness with respect to irreversible adsorption of polar, especially basic, compounds can only be compared with that of reticular bulk polymer stationary phases without any silica skeleton. Unlike pure polymer particles these materials exhibit high pressure stability, only moderate shrinking and swelling effects, and most importantly, high plate numbers, comparable with normal brushtype stationary phases.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02270562
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  • 4
    Electronic Resource
    Electronic Resource
    Liquid chromatography with and of platinum complexes (1981)
    Springer
    Chromatographia 14 (1981), S. 559-566 
    Details
    ISSN: 1612-1112
    Keywords: Reversed phase HPLC ; Normal phase HPLC ; Platinum complexes in mobile phase ; Enantiomeric olefins ; Diasteromeric complexes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Reversed-phase, high-performance liquid chromatography (HPLC) on chemically bonded C18-phases with acetonitrile-water mobile phases, contianing platinum complexes like Zeise's salt C2H4PtCl3, the amine derivative C2H4−PtCl2−NH2−CH(CH3)−C6H5 or the amino acid compound C2H4−PtCl−OOC−CH(N(CH3)2)−C6H5 by analogy with argentation chromatography, was used to increase selectivity for the separation of various types of olefins, amines and heterocyclic compounds. On the other hand, normal-phase adsorption chromatography on silica with n-heptane, dichloromethane and n-propanol mobile phases proves to be an ideal tool for the analytical and preparative separation of diastereomeric platinum complexes of olefins, introduced by Gil-Av, that can be easily preparedin vitro, by the reaction of C2H4−PtCl−OOC−CH(N(CH3)2)−C6H5 with optically active olefins in CH2Cl2. The preparation of the intitial complex as well as its application to the separation of several interesting types of enantiomeric olefins is described and discussed. The number and amount of separable diastereomers formed by the above reaction is strongly influenced by sterical effects. By comparison of the chromatographic pattern of either racemic or partly racemic mixtures, it is possible to decide, which peaks belong to one or the other enantiomeric form of the olefin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02262884
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  • 5
    Electronic Resource
    Electronic Resource
    Fluorinated lignands in HPLC (1981)
    Springer
    Chromatographia 14 (1981), S. 341-344 
    Details
    ISSN: 1612-1112
    Keywords: Reversed phase ; Fluorinated ligands ; HPLC ; Solubility theory
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The chromatographic behaviour of C6F5(CH2)3SiCl3, C6H5(CH2)3SiCl3, CF3(CF2)7CH2CH2SiCl3 and n-C10H21SiCl3 as well as the bonding of these ligands to silica is described. Phases with partially fluorinated ligands show entirely different chromatographic characteristics to analogous phases, where hydrogen replaces fluorine. The silica with the pentafluorophenyl-3-n-propyl-C6F5(CH2)3-ligand has higher k′-values and a better selectivity for aromatic hydrocarbons than that with phenyl-3-n-propyl C6H5(CH2)3-groups, whereas the phase with the fluorinated carbon chain is less useful than the silica modified with n-decyltrichlorosilane n-C10H21SiCl3. The first effect can be explained by complex formation, and the second may be due to a different contact area between the ligand and the solute. The normal hydrocarbon chains hinder each other sterically and expose many adsorption sites, in contrast the perfluorinated chains are sterically fixed and are the first example of “real brushes” in HPLC.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02259232
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  • 6
    Electronic Resource
    Electronic Resource
    Fluorinated ligands in HPLC (1981)
    Springer
    Chromatographia 14 (1981), S. 489-489 
    Details
    ISSN: 1612-1112
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02263542
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  • 7
    Electronic Resource
    Electronic Resource
    Preparative LC separation and isolation of enantiomerically pure olefins (1984)
    Springer
    Chromatographia 18 (1984), S. 119-124 
    Details
    ISSN: 1612-1112
    Keywords: Enantiomeric olefins ; Platinum complexes ; Ligand exchange ; Preparative gas chromatography ; Preparative column-liquid chromatography ; Column switching
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Diastereomer formation by the reaction of chiral olefins with optically active platinum complexes followed by LC separation of the diastereomers, and on-line or off-line release of the olefins from the complexes by ligand exchange yield optically pure enantiomers. The 100% dextrostetatory enantiomer of exo-2-vinylbicyclo[2.2.1]heptane (vinylnorbornane) could be isolated by an off-line method and was used for polarimetric measurements before and after preparative scale gas chromatographic clean-up. The initial valuable platinum complex could be easily recovered without loss.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02258766
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  • 8
    Electronic Resource
    Electronic Resource
    Das erste Inselgallat mit unterschiedlichen Gegen-Kationen: Li3Na2[GaO4] (1982)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 495 (1982), S. 7-15 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The First Nesogallate with Different Counter-cations: Li3Na2[GaO4]We prepared hitherto unknown Li3Na2[GaO4] [Heating mixtures of Na8Ga2O7 and Li2O gives single crystals (Ag-cylinders, 700°C, 14 d), from binary oxides Li2O, Na2O and β-Ga2O3 the compound is obtained as powder (like above, 680°C, 7 d)]. The single crystals are colourless and transparent, the powders are white. A new type of structure is found. The single crystal data are: Pnnm, a = 8.260, b = 7.946, c = 6.515 Å, Z = 4, dx = 3.117, dpyk = 3.073 g · cm-3 [4-circle-diffractometer data, MoKα, 679 from 709 I0(hkl), R = 3.97% and RW = 3.88%, Parameter see text, anisotropic refinement]. The Madelung Part of Lattice Energy, MAPLE, is calculated and discussed.
    Notes: Neu dargestellt wurde Li3Na2[GaO4] [Tempern inniger Gemenge von Na8Ga2O7 mit Li2O liefert Einkristalle (Ag-Bömbchen, 700°C, 14 d), aus den binären Oxiden Li2O, Na2O und β-Ga2O3 erhält man entsprechende Pulverpräparate (wie oben, 680°C, 7 d)]. Die Einkristalle sind farblos und transparent, die Pulver weiß. Der neue Strukturtyp wird durch Einkristalldaten belegt: Pnnm; a = 8,260, b = 7,946, c = 6,515 Å; Z = 4; drö = 3,117, dpyk = 3,073 g · cm-3 [Vierkreisdiffraktometerdaten PW 1100, MoKα; 679 von 709 I0(hkl); R = 3,97% und RW = 3,88%; Parameter siehe Text; anisotrope Verfeinerung].Der Madelunganteil der Gitterenergie, MAPLE, wird berechnet und diskutiert.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19824950102
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  • 9
    Electronic Resource
    Electronic Resource
    Das erste Oxid vom Formeltyp K5[MO4]: K5[TIO4] [1] (1984)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 517 (1984), S. 67-74 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The First Oxide with the Formula Type K5[MO4]: K5[TlO4]Light yellow powder and pale yellow transparent single crystals of K5[TlO4] were newly prepared from mixtures of binary oxides (K2O/Tl2O3) preheated and levigated several times [closed Ag-cylinder, 580°C, 24 h and 600°C, 20 d]. Space group Pbca with a = 1170.4(3), b = 686.1(1), c = 2079.2(5) pm, Z = 8 [four-circle-diffraktometer data, 997 I0(hkl), R = 7.87%, Rw = 5.63%, MoKα] (parameter s. text). The crystal structure belongs to the Na5[GaO4] type. Structural aspects, ECoN and MAPLE are discussed.
    Notes: Neu dargestellt wurden hellgelbes Pulver und blaßgelbe durchsichtige Einkristalle von K5[TIO4] aus mehrmals innig verriebenen, vorgetemperten Gemengen der binären Oxide (K2O/Tl2O3) [geschlossenes Ag-Bömbchen, 580°C, 24 h bzw. bei 600°C, 20 d]. Es liegt die Raumgruppe Pbca mit a = 1170,4(3), b = 686,1(1), c = 2079,2(5) pm, Z = 8 vor. [Vierkreisdiffraktometerdaten, 997 I0(hkl), R = 7,87%, Rw = 5,63%, MoKα] (Parameter s. Text). K5[TlO4] ist isotyp zu Na5[GaO4]. Strukturelle Aspekte, ECoN und MAPLE werden diskutiert.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19845171005
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  • 10
    Electronic Resource
    Electronic Resource
    Das erste Oligo-Oxo-Aluminat: Na14[Al4O13] (1984)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 512 (1984), S. 240-240 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19845120525
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