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  • 11
    Electronic Resource
    Electronic Resource
    Adsorption of tryptophan metabolites from physiological fluids on XAD-2 and determination by single ion monitoringPresented in part at the 10th International Symposium on Advances in Chromatography, Munich, Germany 3-6 November 1975.Abbreviations: T = tryptamine; IAA = indole-3-acetic acid; 5-HT = 5-hydroxytryptamine; 5-HIAA = 5-hydroxyindole-3-acetic acid; 5-HTP = 5-hydroxytryptophan; TP = L-tryptophan; EA = ethyl acetate; ACN = acetonitrile; PFPA = pentafluoropropionic anhydride. (1976)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976), S. 91-96 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Endogenous tryptamine, 5-hydroxytryptamine, indoleacetic acid, 5-hydroxyindoleacetic and tryptophan have been recovered from urine and cerebro-spinal fluid by adsorption on XAD-2 resin (0.3 g). After adsorption of the sample on the resin, desorption with methanol provides a single fraction that contains all of these metabolites. The mass spectra of their pentafluoropropionyl derivatives show prominent ions at m/e 276 and 438 which are characteristic of indoles and 5-hydroxyindoles, respectively, a feature that allows the concurrent determination of all the components of each group by functional group analysis. A method has been developed to carry out single ion monitoring with the peak matching system of an Hitachi RMU-6H mass spectrometer. Identifications are based on the respective Kovats Indices and single ion monitoring of two characteristic ions per compound: tryptophan (m/e 276 and 347); tryptamine (m/e 276 and 289); indoleacetic acid (m/e 276 and 335); 5-hydroxytryptamine (m/e 438 and 451); 5-hydroxyindoleacetic acid (m/e 438 and 497). The method described illustrates the feasibility of assaying biogenic indoleamines and acidic metabolites, as well as their precursor amino acid on a single fraction in contrast to other standard fractionation methods. This is possible even if the mass spectrometer is not equipped with an alternating voltage accelerator provided that it has a peak matcher, although the lack of an alternating voltage accelerator requires two separate injections of the same sample, for quantification and identification; one for the indole profile and another for the 5-hydroxyindole profile. Both profiles can be verified by individual monitoring of the other confirmatory ions. With this method the use of a multiple ion detector would allow a simultaneous determination of all of these metabolites in one gas chromatograph mass spectrometer run.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200030210
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  • 12
    Electronic Resource
    Electronic Resource
    Darstellung, Temperaturverhalten und Kristallstruktur von BiF3 (1977)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 436 (1977), S. 105-112 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation, Temperature Behaviour, and Crystal Structure of BiF3Orthorhombic BiF3 was prepared from BiOCl and HF at 300°C through elimination of oxygen. Thermal analysis showed no transformation up to the melting point of 757°C. The orthorhombic structure of BiF3 can, however, transform into the structure of Tysonit in presence of a small amount of oxygen. The single-crystal X-ray structure determination (553 reflexions, R = 0.050) demonstrated that BiF3 is isostructural with the rare-earth trifluorides of the YF3 type (Pnma). The coordination polyhedron around Bi can be described in terms of a slightly distorted square-antiprisma (CN = 8).
    Notes: Orthorhombisches BiF3 wurde aus BiOCl und Fluorwasserstoff bei 300°C unter Ausschluß von Sauerstoff dargestellt. BiF3 zeigt bis zum Schmelzpunkt bei 757°C keine Phasen-umwandlung. Die orthorhombische BiF3-Struktur kann durch sehr geringe Sauerstoffgehalte in die Tysonitstruktur umgewandelt werden. Die Einkristall-Röntgenstrukturanalyse (553 Reflexe, R = 0,050) ergab, daß BiF3 isotyp mit den Selten-Erd-Trifluoriden vom YF3-Typ (Pnma) ist. Die Koordinationsverhältnisse um Bi können mit Hilfe eines leicht verzerrten quadratischen Antiprismas (KZ = 8) beschrieben werden.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19774360112
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  • 13
    Electronic Resource
    Electronic Resource
    Polyamine metabolism in a rat brain tumor cell line: Its relationship to the growth rate (1975)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 86 (1975), S. 511-521 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: To investigate whether the metabolism of the polyamines putrescine, spermidine and spermine is related to cellular growth rate, we have measured the activities of L-ornithine decarboxylase and S-adenosyl-L-methionine decarboxylase as well as the levels of the polyamines in rat brain tumor cells at various stages of a 7-day in vitro growth period and correlated them with the continuous changes in specific growth rate ([dN[t]/dt]/N[t]). L-Ornithine decarboxylase and S-adenosyl-L-methionine decarboxylase both exhibited their maximal activities at the time of most rapid growth. A high positive correlation between the activities of these enzymes and the specific growth rate of the tumor cells during the entire growth period was demonstrated statistically. The pattern of fluctuation of the spermidine content during the culture cycle was similar to those of the enzyme activities and likewise showed a high positive correlation with the specific growth rate of the tumor cells during the entire growth period. The putrescine content exhibited a low positive correlation, whereas the spermine content exhibited a somewhat higher, but negative correlation with the specific growth rate.The high correlation between the specific growth rate of the tumor cells and the synthesis of the polyamines indicates that these events are primarily associated with processes involved in cell replication. Putrescine and spermidine are thought to participate in the regulation of cellular growth rate; a high content may augment, and a low content may restrain, cellular growth rate.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1040860308
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  • 14
    Electronic Resource
    Electronic Resource
    Pyrenesulfonyl azide as a fluorescent label for the study of protein-lipid boundaries of acetylcholine receptors in membranes (1979)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. 327-338 
    Details
    ISSN: 0091-7419
    Keywords: AcChR-enriched membranes ; pyrenesulfonyl azide ; fluorescent probes ; photolabeling ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Acetylcholine receptor (AcChR) enriched membrane fragments from Torpedo californica electroplax were labeled by in situ photogenerated nitrenes from a hydrophobic fluorescent probe, pyrene-1-sulfonyl azide. Preferential photolabeling of membrane proteins, mainly AcChR, has been achieved and there is a pronounced exposure of the 48,000 and 55,000 molecular weight subunits of AcChR to the lipid environment of the membrane core.Covalent attachment of the photogenerated fluorescence probe does not perturb the α-neurotoxins' binding properties of membrane-bound AcChR or the desensitization kinetics induced by prolonged exposures to cholinergic agonists. Non-covalent photoproducts can be conveniently removed from labeled membrane preparations by exchange into lipid vesicles prepared from electroplax membrane lipids. Fluorescence features of model pyrene sulfonyl amide derivatives, such as fine vibrational structure of emission spectra or fluorescence lifetimes, are highly sensitive to the solvent milieu. The covalently bound probe shows similar fluorescence properties in situ. PySA photoproducts have great potential to spectroscopically monitor neurotransmitter induced events on selected AcChR subunits exposed to the hydrophobic environment of membranes.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400110308
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  • 15
    Electronic Resource
    Electronic Resource
    Stopped-flow study of the gas-phase reaction of ozone with organic sulfides: Dimethyl sulfide (1978)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 10 (1978), S. 433-452 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The autoinhibiting reaction of ozone with dimethyl sulfide (DMS), has been studied at 296°K and 1.1 kPa (8 torr) as a function of the concentrations of both reactants. The major products of the reaction are H2CO, H2O, CO, and SO2. The specific rate of primary attack of O3 on DMS is immeasurably slow. It is suggested that the rapid overall rate observed for this reaction is due to a chain reaction initiated by the very slow primary reaction. It is concluded that reaction (1) cannot be important under atmospheric conditions and that the major loss process for DMS in the atmosphere is probably reaction with photochemically generated free radicals.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/kin.550100503
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