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  • Electronic Resource  (2)
  • Biological monitoring  (1)
  • Cell growth  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Determination of dichlorobenzidine-hemoglobin adducts by GC/MS-NCI (1997)
    Springer
    International archives of occupational and environmental health 69 (1997), S. 240-246 
    Details
    ISSN: 1432-1246
    Keywords: Key words Dichlorobenzidine ; Hemoglobin adducts ; Biological monitoring ; GC/MS-NCI
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  A method based on gas chromatography/ mass spectrometry–negative ion chemical ionization detection (GC/MS-NCI) was developed for the determination of 3,3′-dichlorobenzidine (DCB)-hemoglobin adducts. Adducts were released from hemoglobin by mild alkaline hydrolysis and determined by GC/MS-NCI after extraction and derivatization with heptafluorobutyric anhydride (HFBA). 2,2′-DCB was used as internal standard and the recovery of the diarylamine derivatives in the overall procedure was 65–88%. The limit of detection attained was below 0.1 ng/g hemoglobin for DCB as well as for the metabolite N-acetyl-3,3′-dichlorobenzidine (acDCB). The method was shown to be linear up to 150 ng/g hemoglobin. In the NCI mass spectra of the HFB derivatives the dominant ion is (M–HF)-. Due to the presence of two chlorines in the diarylamines, the characteristic ratio of 1.5 for m/z 624 to 626 (for diHFB-DCB and diHFB-2,2′-DCB) and m/z 470 to 472 (for HFB-acDCB) can be observed and used for identification. The method was applied to the determination of DCB-hemoglobin adducts formed in young female Wistar rats after treatment for 4 weeks with 0.006%, 0.0012% or 0.00024% DCB via the drinking water. Two adducts were detectable by GC/MS-NCI after alkaline hydrolysis of hemoglobin samples, extraction and derivatization. The structure of these adducts could be assigned to DCB and acDCB by co-chromatography with the synthetic standards and by the presence of the characteristic ion (M–HF)-. Assessment of the time dependence of hemoglobin adduct formation during subchronic treatment with DCB revealed an increase in adduct levels during weeks 1–3. After this time adduct levels essentially remained constant. In hemoglobin samples isolated from animals treated for 4 weeks with DCB a dose-proportional increase in the total amount DCB- and acDCB-hemoglobin adducts from 8.1 ng DCB/g hemoglobin at 0.3 mg/kg body weight per day (0.00024% in drinking water) to 159.9 ng DCB/g hemoglobin at 5.8 mg/kg body weight per day (0.006% in drinking water) was observed. The ratio of the DCB adduct to the acDCB adduct was strongly dose dependent. At low DCB doses the acDCB- and DCB adducts were formed at similar levels, whereas at high DCB doses the DCB adduct was predominant.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004200050142
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Influence of elevated expression of rat wild-type PMP22 and its mutant PMP22 Trembler on cell growth of NIH3T3 fibroblasts (1997)
    Springer
    Cell & tissue research 287 (1997), S. 459-470 
    Details
    ISSN: 1432-0878
    Keywords: Key words: Apoptosis ; Cell growth ; Growth-arrest-specific gene ; Myelin ; NIH3T3 cells ; PMP22
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. The peripheral myelin gene PMP22 is the rat and human homologue of the murine growth-arrest-specific gene gas3. The biological function of PMP22 is unknown, but recent progress in the analysis of rat Schwann cells expressing altered levels of PMP22 revealed that one role of PMP22 is as a negative growth modulator. We have investigated the influence of rat PMP22 (rPMP22) and a mutant of PMP22 (rPMP22Tr) resembling the murine trembler mutation on cell growth of retrovirus-vector-infected mouse NIH3T3 cells. Transduced cells carrying the two different sense constructs expressed rPMP22 and rPMP22Tr mRNAs and proteins. Elevated levels of rPMP22 and rPMP22Tr significantly reduced fibroblast growth as judged by proliferation assays. Despite a negative modulatory influence of rPMP22 and rPMP22Tr on cell proliferation, cell cycle analyses by flow cytometry did not reveal an influence of rPMP22 or rPMP22Tr on the synchronous progression of resting NIH3T3 cells from G0 into S phase. However, cell cycle analyses by flow cytometry of asynchronously dividing cultures demonstrated that the expression of rPMP22 and rPMP22Tr increased the fraction of cells in the G1 phase of the cell cycle. Furthermore, cell death analyses revealed that, in contrast to control cells and cells carrying the rPMP22Tr construct, a significantly increased fraction of NIH3T3 cells expressing rPMP22 exit the proliferation compartment showing hallmarks of programmed cell death. These results indicate that (i) rPMP22 and rPMP22Tr act as negative modulators of proliferation in murine fibroblasts probably through extension of the G1 phase of the cell cycle and (ii) rPMP22 but not rPMP22Tr promotes programmed death of these cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410050770
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    Paper (German National Licenses)
    Fulltext
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