ESR evidence for the hydroxyl radical formation in aqueous suspension of quartz particles and its possible significance to lipid peroxidation in silicosis.
Electron spin resonance (ESR) spectrum of the hydroxyl (.OH) radical spin adduct with the spin trap 5,5-dimethyl-1-pyrroline-N-oxide has been obtained in suspensions of freshly ground quartz particles. The concentration of the spin adduct (and hence of the .OH radicals) increases with the amount of grinding. The dust's potential for the generation of the .OH radicals is maximum when fresh (i.e., immediately after grinding) and decreases to 50% in about a day on storage in air. Studies involving metal chelates indicate that the .OH radical formation involves mainly the silica surface and H2O rather than the Fenton reaction. The results suggest that hydroxyl radical reaction(s) could be important in the lipid peroxidation and fibrogenicity by quartz dust, particularly in acute silicosis.
Shi
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Department of Chemistry, West Virginia University, Morgantown 26506.
Dalal
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Vallyathan
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D004578:Electron Spin Resonance Spectroscopy; D005609:Free Radicals; D006801:Humans; D006878:Hydroxides / Q000032:analysis*; D017665:Hydroxyl Radical; D007700:Kinetics; D015227:Lipid Peroxidation; D011791:Quartz / Q000009:adverse effects / Q000032:analysis*; D012822:Silicon Dioxide / Q000032:analysis*; D012829:Silicosis / Q000209:etiology / Q000378:metabolism; D013535:Suspensions
D005609:Free Radicals; D006878:Hydroxides; D013535:Suspensions; D011791:Quartz; D017665:Hydroxyl Radical; D012822:Silicon Dioxide