Title of article
Ascorbyl radical formation in patients with sepsis: Effect of ascorbate loading
Author/Authors
Helen F. Galley، نويسنده , , Michael J. Davies، نويسنده , , Nigel R. Webster، نويسنده ,
Issue Information
روزنامه با شماره پیاپی سال 1996
Pages
5
From page
139
To page
143
Abstract
Patients with sepsis have low concentrations of antioxidants, including ascorbic acid, and also have increased concentrations of markers of free radical damage. Although ascorbic acid is a potent antioxidant, it can act as a prooxidant by promoting iron-catalysed reactions. We measured baseline total vitamin C and bleomycin-detectable “free” iron levels and ascorbyl radical concentrations before and after intravenous infusion of 1 g ascorbic acid in patients with sepsis and healthy control subjects. Vitamin C concentrations were decreased in patients compared to healthy subjects (p<0.0001), and “free” iron was increased (p < 0.002). Preinfusion ascorbyl radical concentrations were not different in patients and controls. Postinfusion ascorbyl radical levels increased in both controls and patients, with larger increases in healthy subjects (p < 0.0001), suggesting suboptimal basal vitamin C levels and increased scavenging of a constant oxidant pool by ascorbate in the controls. In the patients, who were all vitamin C deficient, infused ascorbate was rapidly consumed, either via the promotion of redox cycling of iron or as a result of radical scavenging. This study demonstrates markedly different handling of infused ascorbate in patients with sepsis and healthy subjects, and further studies are needed to elucidate the relative anti- and pro-antioxidant mechanisms of ascorbate in patients with raised “free” iron levels.
Keywords
ascorbic acid , Electron paramagnetic resonance spectroscopy , Iron , vitamin C , free radicals , Septicemia , Spin traps
Journal title
Free Radical Biology and Medicine
Serial Year
1996
Journal title
Free Radical Biology and Medicine
Record number
517246
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