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  • DMF-mercapturic acid  (1)
  • DNA content  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    International archives of occupational and environmental health 67 (1995), S. 41-46 
    ISSN: 1432-1246
    Keywords: N,N-Dimethylformamide ; Urine ; DMF-mercapturic acid ; N-methylformamide ; Formamide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Some methods for analysing N,N-dimethylformamide and its metabolites [hydroxymethyl-N-methylformamide, hydroxymethylformamide and N-acetyl-S-(N-methylcarbamoyl)cysteine] in the urine of exposed workers are described. Unchanged dimethylformamide was measured after pretreatment of urine (2 ml) with silica gel cartridges and elution with methanol. The gas chromatographic analysis using a nitrogen phosphor detector made it possible to detect N,N-dimethylformamide in urine even when workers were exposed to low concentrations of the solvent (about 1 mg/m3). N-Hydroxymethyl-N-methylformamide and N-hydroxymethylformamide were analysed as N-methylformamide and formamide respectively after direct injection of urine into the gas chromatograph. The injection port temperature played an important role in the gas chromatographic determination of these products. Reliable results were obtained when direct or split injections were performed at 250°C. The splitless injection gave the same reliable results at 150°C. In urine samples from occupationally non-exposed persons, N-methylformamide could not be detected. In contrast, formamide (or its precursor, hydroxymethylformamide) was present in every urine sample. Our results in respect of 19 urine samples analysed with the injection port of the gas chromatograph at 250°C gave a mean of 8.6 mg/l of formamide. N-Acetyl-S-(N-methylcar-bamoyl)cysteine was determined using a modified method for analysing organic acid in urine samples. The metabolite was extracted with ethyl ether in an acid environment, treated with a silylating reagent and measured by gas chromatography/mass spectrometry.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Sexual plant reproduction 1 (1988), S. 202-207 
    ISSN: 1432-2145
    Keywords: Asparagus ; DNA complexity ; DNA content ; Male and female mRNAs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary As a first approach in investigating the genetical bases of sexual dimorphism in the dioecious plant Asparagus offcinalis L. at the molecular level, we have determined DNA content per cell, DNA sequence complexity and mRNA activities in both developing and mature male and female flowers of Asparagus. 2C DNA content (around 3.9 pg) was independent of sex and rather low when compared to other Liliiflorae; sequence complexity, however, showed a high proportion of repeated sequences. Polyadenylated mRNA from male and female flowers at young and mature stages of development were assayed by in vitro translation in the presence of [35S]methionine, and the synthesized proteins were analysed by two-dimensional gel electrophoresis. Results have shown that there are no appreciable differences in polypeptide patterns from male and female flowers at a young stage of development, while specific sequences of mRNA are produced only very late during the development, most likely linked to the appearance of mature pollen grains and mature megagametophy tes.
    Type of Medium: Electronic Resource
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