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  • 1
    ISSN: 1432-0738
    Keywords: AN 1 ; Amphetamine ; Doping Controls ; AN 1 ; Amphetamin ; Dopingkontrollen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Nach Einnahme von AN 1 (1) (α-Phenyl-α-N-(1-phenyl-isopropyl)-amino-acetonitril) konnte im Urin von Versuchspersonen mit Hilfe der Kombination GC-MS Amphetamin (2) nachgewiesen werden. Da dieses Psychotonikum frei im Handel erhältlich ist, sollte dieser Befund in Zukunft bei der Durchführung von Dopingkontrollen berücksichtigt werden.
    Notes: Abstract After oral administration of the psychotonic AN 1 (1) (α-Phenyl-α-N-(1-phenylisopropyl)-amino-acetonitril), amphetamine (2) could be detected in the urine of volunteers by GC-MS-analysis. Since this drug is commercially free available this finding should be considered in doping controls in the future.
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  • 2
    ISSN: 1434-4475
    Keywords: Amino acid conjugates ; Conjugates of amino acids ; Metabolic profiling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The conjugates of glycine with furan 2,5-dicarboxylic acid and of picolinic acid as well as a conjugate of pyroglutamic acid with phenylacetic acid, previously unknown as natural metabolites, were detected to be normal metabolites in human urine.
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  • 3
    ISSN: 1434-4475
    Keywords: Vegetables ; Fatty acid fraction ; Branched fatty acids ; Hydroxy-fatty-acids ; Cruciferae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Most vegetables contain different amounts of iso- and anteiso-fatty acids, α-methylated acids were detected too, but so far only in tomatoes. Vegetables contain a great variaty of hydroxylated acids, especially α-hydroxy acids. The detected iso- and anteiso-fatty acids and alcohols may be the source of similar branched chain acids identified earlier in rather high amounts in skin and hairs of man and animals. They might also be the source of branched aldehyde components in plasmologens.
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  • 4
    ISSN: 1434-4475
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Abstract Secondary alcohols of higher molecular weight undergo stepwise fragmentation in the mass spectrometer. In a first step, parent molecular ions give rise toM-18 fragments and key fragments formed by α-cleavage, i.e. cleavage of carbon-carbon bonds α to the hydroxyl group. Nearly all other fragments arise from further cracking of α-cleavage products by elimination of water and C n H2n molecules producing C n H2n−1 + fragments. The course of this fragmentation was studied by means of deuterated compounds. α-cleavage products of tertiary alcohols, however, eliminate alcohol molecules in dependence on the alkyl chain length. This was corroborated by the detection of peaks of meta-stabile ions.
    Notes: Zusammenfassung Höher molekulare sekundäre Alkohole werden im Massenspektrometer stufenweise abgebaut. Als primäre Spaltprodukte entstehen aus den MolekülionenM-18-Fragmente und Schlüsselbruchstücke, die durch Bruch einer zur Hydroxylgruppe benachbarten C−C-Bindung gebildet werden (α-Spaltung). Nahezu alle übrigen Fragmente entstehen durch weiteren Zerfall der α-Spaltungsprodukte. Zunächst wird aus diesen Wasser eliminiert, danach C n H2n -Moleküle unter Bildung von C n H2n−1 +-Bruchstücken. Der Verlauf dieser Abbaureaktionen worde mit Hilfe von deuteriummarkierten Verbindungen studiert. Dagegen zeigen die α-Spaltungsprodukte tertiärer Alkohole vorwiegend die Eliminierung von Alkoholmolekülen in Abhängigkeit von der Kettenlänge der Alkylreste. Dies konnte durch das Auffinden von Banden metastabiler Ionen belegt werden.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Monatshefte für Chemie 101 (1970), S. 141-156 
    ISSN: 1434-4475
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Abstract Paucine can be degradated to catechol, caffeic acid and putrescine. This together with spectroscopic data allows us to deduce formula3 for paucine.
    Notes: Zusammenfassung Beim Abbau von Paucin wird Brenzcatechin, Kaffeesäure und Putrescin erhalten. Daraus und aus spektroskopischen Befunden ergibt sich für das Paucin die Strukturformel3.
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  • 6
    ISSN: 1434-4475
    Keywords: Vegetables ; Potato tubers ; Fatty acid oxidation ; Lipoxygenases ; Cruciferae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Potato tubers und vegetables, introduced into the body contain — in dependance if boiled or not — very different amounts of multiple unsaturated fatty acids. In boiled vegetables linoleic and linolenic acid remain unchanged. In contrast, if the vegetable is shred and then analysed, the content of multiple unsaturated fatty acids is lowered for a factor of 2–5. If vegetable is shred, lipoxygenases are liberated, resulting in oxidizing the multiple unsaturated acids. The lipoxygenases are destroyed if vegetable is cooked before shreding. An easy comparison of the effect of lipoxygenases on fatty acid can be made by gas chromatography. The effect is especially strong incruciferae e.g. in cabbage or cauliflower.
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  • 7
    ISSN: 1434-4475
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Abstract The combination of a gaschromatograph with a high resolution mass spectrometer may provide in the investigation of steroids, isolated from natural sources, fast information about otherwise barely detectable minor steroid metabolites. The limit of detection is about 1 γ. Free steroids show more structure specific spectra than their corresponding trimethylsilyl derivatives. Therefore the preparation of trimethylsilyl derivatives for the purpose of gaschromatographic separation should be avoided if possible. If low volatility necessitates the preparation of a derivative, in most cases the preparation of keto derivatives from hydroxysteroids should be preferred to the preparation of trimethylsilyl ethers. Reactions can be carried out with the mixture, so that-without preparation of pure samples-at least partial structure determinations are possible with 10–20 γ.
    Notes: Zusammenfassung Die Kombination eines Gaschromatographen mit einem hochauflösenden Massenspektrometer kann bei der Untersuchung von Steroidgemischen, die aus biologischen Materialien isoliert wurden, rasche Information über sonst kaum nachweisbare Steroidmetaboliten liefern. Die Erfassungsgrenze liegt bei etwa1 γ. Freie Steroide zeigen strukturspezifischere Spektren als ihre Trimethylsilylderivate, so daß, wenn immer möglich, auf eine Silylierung zur gaschromatographischen Trennung verzichtet werden sollte. Ist wegen der Schwerflüchtigkeit der Verbindung eine Derivatbildung notwendig, so ist die Umwandlung von Hydroxysteroiden in entsprechende Ketosteroide in den meisten Fällen einer Trimethylsilylierung vorzuziehen. Umsetzungen können im Gemisch ausgeführt werden, so daß zumindest eine teilweise Strukturaufkläurung ohne Reinisolielierung der Probe mit Mengen von 10 bis 20 γ möglich ist.
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  • 8
    ISSN: 1434-4475
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The syntheses and mass spectra of the four 3,17β-dihydroxyandrostane-11,16-diones and of the two 17β-hydroxyandrostane-3,11,16-triones are described. These compounds decompose in the mass spectrometer in a different way than androstanes containing a carbonyl group in the position 11 or 16: First they eliminate the C-atoms 15 to 17. Then a cleavage of the C-atoms of the ringA plus C-6 follows resulting in key ions which contain the ringC and the C-atom 7. The connection of theA/B-ring system can be deduced by the spectra for all described compounds. The unequivocal determination of the configuration of the 3-hydroxy group is possible only for the 3,17β-dihydroxy-5β-androstan-11,16-diones.
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  • 9
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Physiologia plantarum 119 (2003), S. 0 
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Plants and mammals contain polyunsaturated fatty acids (PUFAs) in their membranes. PUFAs belong to the most oxygen sensitive molecules encountered in nature. It would seem that nature has selected this property of PUFAs for signalling purposes: PUFAs are stored in the surface of cells and organelles not in free form but conjugated to phospho- and galactolipids. Any change in membrane structure apparently activates membrane-bound phospholipases, which cleave the conjugates. The obtained free PUFAs are substrates for lipoxygenases (LOX). These transform PUFAs to lipidhydroperoxides (LOOHs). LOOHs are converted to a great variety of secondary products. These lipid-peroxidation (LPO) products and the resulting generated products thereof represent biological signals, which do not require a preceding activation of genes. They are produced as a non-specific response to a large variety of external or internal impacts, which therefore do not need interaction with specific receptors. When, due to an external impact, e.g. attack of a microorganism, or to a change in temperature, the amount of liberated free PUFAs exceeds a certain threshold, LOX commit suicide. Thus iron ions, located in the active centre of LOX, are liberated. Iron ions react with LOOHs in the close surroundings by generating alkoxy radicals (LO.). These induce a non-enzymatic LPO. A fraction of the LO. radicals generated from linoleic acid (LPO products derived from linoleic acid play a dominant role in signalling which was previously overlooked) is converted to 2,4-dienals which induce the programmed cell death (PCD) and the hypersensitive reaction (HR). While peroxyl radicals (LOO.) generated as intermediates in the course of an enzymatic LPO are transformed within the enzyme complex to corresponding anions (LOO–), and thus lose their reactivity, peroxyl radicals generated in non-enzymatic reactions are not deactivated. They not only react by abstraction of hydrogen atoms from activated X-H bonds of molecules in their close vicinity, but also by epoxidation of double bonds and oxidation of a variety of biological molecules, causing a dramatic change in molecular structure which finally leads to cell death. As long as reducing agents, like glutathione, or compounds with free phenolic groups are available, the amount of LOOHs is kept low. Cell death is induced in a defined way by apoptosis. But when the reducing agents have been consumed, PCD seems to switch to necrotic processes. Thus proliferation is induced by minor changes at the cell membrane, while slow changes at cell membranes are linked with apoptosis (e.g. response to attack of microorganisms or drought) and necrosis (severe wounding), depending only on the amount, but not on the type, of applied stimulus.
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  • 10
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 4 (1977), S. 155-158 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectra of antipyrine metabolites show characteristic fragmentation patterns which depend on the presence and position of functional groups. A substituent at position 4 is indicated by an intense key fragment at m/e 56 and a substituent at the methyl group in position 3 causes a significant increase in the intensity of the peak at m/e 82. The fragment at m/e 96, which is characteristic for antipyrine itself, is suppressed if there is a substituent in either position 3 or 4. Mass spectra of the glucuronides of 4-hydroxyantipyrine and 3-hydroxymethylantipyrine are also discussed.
    Additional Material: 8 Ill.
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