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  • 1
    Electronic Resource
    Electronic Resource
    Nucleoside antibiotics. Biosynthesis of arabonofuranosyladenine by Streptomyces antibioticus. 10 (1972)
    s.l. : American Chemical Society
    Biochemistry 11 (1972), S. 911-916 
    Details
    ISSN: 1520-4995
    Source: ACS Legacy Archives
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/bi00755a034
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  • 2
    Electronic Resource
    Electronic Resource
    Electrospray source parameters and their effect on 2′- deoxynucleotide spectra (1995)
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 9 (1995), S. 870-870 
    Details
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/rcm.1290090930
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  • 3
    Electronic Resource
    Electronic Resource
    Determination of hydroxypropylhistidine in haemoglobin as a measure of exposure to propylene oxide using high resolution gas chromatography mass spectrometryA preliminary communication of this work was presented at the Joint Meeting of the Royal Society, of Chemistry and the British Mass Spectrometry Society, Dundee, UK, 1981. (1982)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 9 (1982), S. 69-71 
    Details
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The alkylating agent propylene oxide is a potential carcinogen. Exposure to this compound leads to the formation of N-3′-(2-hydroxypropyl)histidine in protein. A sensitive and specific method has been developed for the determination of this alkylated amino acid in rat and human haemoglobin using high resolution gas chromatography with selected ion monitoring. Globin isolated from blood was hydrolysed with 6 M HCI and the protein hydrolysate chromatographed on a Dowex 50W H+ column. The amino acids in the partially purified extract were analysed as N-heptafluorobutyryl methyl esters using an SE-52 fused silica capillary column. Quantification was made by monitoring the ion m/z 560 [M — COOCH3]+ derived from the derivatized hydroxypropylhistidine in the sample and the corresponding ion at m/z 565 from the pentadeutero analogue of the alkylated amino acid added initially to the globin as an internal standard. The method has been used to quantify hydroxypropylhistidine down to levels of 2 μg gm-1 haemoglobin and has been applied to studies in rats exposed to propylene oxide.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200090205
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  • 4
    Electronic Resource
    Electronic Resource
    Tandem mass spectrometric approaches for the analysis of alkylguanines in human urine (1993)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 28 (1993), S. 552-558 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Human exposure to carcinogenic alkylating agents can lead to the formation of covalently bound adducts in DNA, some of which are excreted in urine as alkylated purines following DNA degradation and repair. Tandem mass spectrometric methods have been developed for the qualitative and quantitative determination of such alkylpurines in human urine. Short-chain alkyl- and hydroxyalkylguanines have been synthesized with the substituents at the N-7-, O6- and N2-positions of guanine. Examination of the product ion scans of their molecular ions (electron impact (EI) ionization) revealed that the ion at m/z 151, [guanine]+, was common to all of the alkylguanines studied, with the exception of the methylated analogues. Precursor ion scans of this ion on partially purified human urine extracts showed the presence of several ions (e.g. m/z 179, 195) which were consistent with molecular ions for alkylguanines. The presence of these and other constituents was confirmed by product ion spectra of molecular ions (EI and fast atom bombardment), and by high-performance liquid chromatographic separation prior to tandem mass spectrometry (MS/MS). Evidence was obtained for the presence of N-7-methyl-, N2-dimethyl-, N2-dimethyl-, N2-ethyl- and N-7-(2-hydroxyethyl)guanine. Quantitative methods were established for these five alkyl guanines using gas chromatography mass spectrometry (GC/MS) and GC/MS/MS. Deuterated internal standards were synthesized and added to the urine prior to extraction of alkylpurines by Sep-Pak cartridge chromatography. The products were converted into their tert-butyldimethylsilyl derivatives and analysed by selected ion monitoring (SIM) of [M - 57]+ or by multiple reaction monitoring (MRM) of the fragmentation M+· → [M - 57]+. The MRM method yielded values for N-7-methylguanine of 2.57 ± S.D. 1.32 mg day-1 (n = 6), N2-methylguanine of 0.31 ± 0.10 mg day-1 (n = 10) and N2-dimethylguanine of 0.21 ± 0.23 mg day-1 (n = 10). N2-Ethyl- and N-7-(2-hydroxyethyl)guanine could only be detected by SIM at levels of ∼0.5 and 2 μg day-1, respectively. The MRM analyses, although inherently less sensitive than the SIM analyses, exhibit greater selectivity and consequently fewer contaminant ions.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210280514
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  • 5
    Electronic Resource
    Electronic Resource
    The microsomal hydroxylation of aniline mustard-d3 [n, n-di- (2- chloroethyl) - 2,4,6-trideuterioaniline] (1975)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 2 (1975), S. 107-111 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The metabolism by rat liver microsomes of the 2,4,6-trideuterio derivative of aniline mustard [N, N-di-(2-chloroethyl)aniline] in admixture with unlabelled material, has been studied. The resulting p-hydroxy derivative was isolated and examined by mass spectrometry. The extent of migration of deuterium from the p- to the m-position, determined from the ratio of trideuteriated to dideuteriated product, was 46%, but the protium and deuterium forms were hydroxylated at the same rate (zero isotope effect).
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200020207
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  • 6
    Electronic Resource
    Electronic Resource
    Application of deuterium labelling mass spectrometry in a study of the metabolism of the enantiomers of cyclophosphamideAbbreviation: CP = cyclophosphamide. (1977)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 4 (1977), S. 371-375 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The antitumour agent cyclophosphamide - {2-[bis(2-chloroethyl)amino]-tetrahydro-2H -1,3,2-oxaza-phosphorine 2-oxide} - is chiral owing to asymmetry at phosphorus. The differential metabolism of the enantiomers [(+)-cyclophosphamide and (-)-cyclophosphamide] can be monitored by mass spectrometry if pseudoracemates consisting of either unlabelled [2H0] (+)- and tetradeuterated [2H4] (-)-cyclophosphamide or of [2H0](-) and [2H4](+) enantiomers are administered. Using this principle, methodology has been developed for determining the enantiomer ratios of cyclophosphamide and two metabolites, 4-ketocyclophosphamide {2-[bis(2-chloroethyl)amino] tetrahydro-2H-1,3,2-oxazaphosphorin-4-one 2-oxide} and carboxyphosphamide [2-carboxyethyl N,N-bis(2-chloroethyl)phosphorodiamidate] recovered from the urine of mice. The drug and the two metabolites were quantified using [2H10]cyclophosphamide, 4-keto-[2H8]cyclophosphamide and [2H6]carboxyphosphamide respectively, as internal standards. The amount of cyclophosphamide excreted was small and neither enantiomer preponderated markedly, but the minor metabolite, 4-ketocyclophosphamide, was markedly depleted in the enantiomer derived from (-)-cyclophosphamide, whereas the major metabolite, carboxyphosphamide, was slightly depleted in the enantiomer derived from (+)-cyclophosphamide.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200040609
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  • 7
    Electronic Resource
    Electronic Resource
    Tandem mass spectrometry study of urinary alkylated purines (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 17 (1988), S. 143-145 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    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/bms.1200170213
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  • 8
    Electronic Resource
    Electronic Resource
    Observations on the mechanism of hydroxylation of cyclophosphamide by rat liver microsomes: The metabolism of cyclophosphamide-4-d2 (1974)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 1 (1974), S. 130-136 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The metabolism of cyclophosphamide-4-d2 (2-[bis(2-chloroethyl)amino]-tetrahydro-4,4-dideuterio-2H-1,3,2-oxazaphosphorine 2-oxide), was studied. The first detectable metabolite was a hydroxy derivative which was trapped with ethanol. Mass spectrometry of the resulting two ethoxy derivatives and of the deuterated acrolein 2,4-dinitrophenylhydrazones formed therefrom via reaction with acidic 2,4-dinitrophenylhydrazine, afforded evidence that the ethoxy substituents were at C-4, which was therefore the position of the original hydroxy substituent. The mass spectrum of the deuterated acrolein 2,4-dinitrophenylhydrazone obtained from the total reactive metabolites was used to estimate the ratio of 4- to 6-hydroxylation. The rate of metabolism and the antitumour activity of cyclophosphamide and its 4-d2 analogue were compared.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200010209
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  • 9
    Electronic Resource
    Electronic Resource
    Special feature: Perspective. Mass spectrometric detection of carcinogen adducts (1995)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 30 (1995), S. 1369-1379 
    Details
    ISSN: 1076-5174
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Genotoxic carcinogens interact with nucleic acids and proteins to yield covalently bound products (adducts), the quantitative determination of which has been proposed as a biomonitor of human exposure to carcinogens. Mass spectrometry is playing a leading role both in the structural characterisation and in the quantitative determination of these carcinogen adducts. In particular electrospray ionisation and matrix assisted laser desorption ionisation are being increasingly used in nucleotide and protein adduct detection and in sequencing of carcinogen-modified oligonucleotides and peptides. Quantitative determination of carcinogen-modified nucleic acid bases and protein amino acids is generally carried out by GC/MS or GC/MS/MS, the highest sensitivity being achieved using negative ion chemical ionisation. These techniques are now being applied to samples from humans exposed to carcinogens from environmental, medicinal and occupational sources.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jms.1190301002
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  • 10
    Electronic Resource
    Electronic Resource
    Approach to the quantitation of alkylated amino acids in haemoglobin by gas chromatography mass spectrometryA preliminary communication of this work was presented at the 8th International Mass Spectrometry Conference, Oslo (1979). Abbreviations: PFP = pentafluoropropionyl; HFB = heptafluorobutyryl. (1980)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 7 (1980), S. 41-46 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: As a result of the increasing concern over the environmental exposure of humans to carcinogenic alkylating agents, assay methods are being developed in order to quantitate the extent of in vivo alkylating reactions. Such methods will be of value also in connection with the use of alkylating agents as anti-cancer drugs. The reactions carried out by these compounds include the alkylation of cysteine in proteins, and a procedure has now been developed for the estimation of S-methylcysteine in haemoglobin following exposure of rats to the carcinogen methyl methanesulphonate. Haemoglobin is particularly appropriate for the analysis of alkylating agent reactions as this protein is readily available from blood and has a long in vivo half-life. The analytical method involved isolation of globin from blood, hydrolysis in 6 M hydrochloric acid, partial purification of S-methylcysteine by chromatography on Dowex 50 ion exchange resin, and subsequent analysis by gas chromatography mass spectrometry. The amino acid mixtures were derivatized by n-butyl ester formation and N-heptafluorobutyrylation, and were chromatographed on a capillary column coated with OV-101 or Chirasil-Val using a solid injection system. For the mass spectrometric determination [2H3]-S-methylcysteine was employed as an internal standard. Monitoring of the [MH]+ ion of derivatized S-methylcysteine in chemical ionization (isobutane) allowed the detection of 10 pg of the compound with a signal-to-noise ratio of 20:1.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200070109
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