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  • 1
    ISSN: 1434-0879
    Keywords: Key words Nephrolithiasis ; Calcium oxalate ; Osteopontin ; Macromolecule inhibitor ; Rat kidney
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Human urine contains several macromolecules which inhibit calcium oxalate crystallization. Osteopontin (or uropontin), a secreted phosphoglycoprotein with the amino acid sequence Arg-Gly-Asp (RGD) and high affinity to hydroxyapatite, is one such inhibitor. To investigate the action of this protein on renal stone formation, the expression osteopontin gene in normal and chemically induced urolithiasis rat kidney was compared at both mRNA and protein levels. Northern blot analysis shown a significant increase of osteopontin mRNA level in stone-forming rat kidney compared with normal ones. In an in situ hybridization study, we localized the transcripts of the osteopontin gene in epithelial cells of both distal and collective tubules, and found a remarkably strong signal in stone-forming rats. The amount and distribution of the protein in kidney from immunocytochemistry staining showed the same pattern as seen in situ hybridization. These findings indicate that osteopontin may be an important macromolecule in the normal endogenous defence against the formation of urinary calculi.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-1246
    Keywords: Key words Biological monitoring ; Blood analysis ; Diffusive sampling ; Head-space GC ; Tetrachloroethene ; Urinalysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Objective: The present study was initiated to examine a quantitative relationship between tetrachloroethene (TETRA) in blood and urine with TETRA in air, and to compare TETRA in blood or urine with trichloroacetic acid (TCA) in urine as exposure markers. Methods: In total, 44 workers (exposed to TETRA during automated, continuous cloth-degreasing operations), and ten non-exposed subjects volunteered to participate in the study. The exposure to vapor was monitored by diffusive sampling. The amounts of TETRA and TCA in end-of-shift blood and urine samples were measured by either head-space gas chromatography (HS-GC) or automated methylation followed by HS-GC. The correlation was examined by regression analysis. Results: The maximum time-weighted average (TWA) concentration for TETRA-exposure was 46 ppm. Regression analysis for correlation of TETRA in blood, TETRA in urine and TCA in urine, with TETRA in air, showed that the coefficient was largest for the correlation between TETRA in air and TETRA in blood. The TETRA in blood, in urine and in air correlated mutually, whereas TCA in urine correlated more closely with TETRA in blood than with TETRA in urine. The TCA values determined by colorimetry and by the GC method were very similar. The biological marker levels at a hypothetical exposure of 25 ppm TETRA were substantially higher in the present study than were the levels reported in the literature. Possible reasons are discussed. Conclusions: Blood TETRA is the best marker of occupational exposure to TETRA, being superior to the traditional marker, urinary TCA.
    Type of Medium: Electronic Resource
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