Mechanisms of Thiol Reaction with Oxygen: Implications for Hyperthermic and Radiation Therapies
Cysteamine (MEA) and other thiols have been used in research as radioprotecting agents1–4 and anticarcinogens.5–6 More recently MEA has been found to enhance the effects of hyperthermic sterilization? and to protect against the cytotoxicity of misonidazole.8–9 Despite its possible therapeutic potential, MEA is known to be cytotoxic, and it has been shown that low concentrations of MEA (less than 1 mM) kill cells more effectively than higher concentrations. 10,11 MEA toxicity has been attributed to the production of peroxide via the spontaneous reaction with oxygen which is metal ion catalysed.10,12–16 our research purpose was to extend the earlier observations on MEA-linked peroxide production10, 11 because of the possible importance in hyperthermic sterilization as well as in radiation biology. We have measured thiol-linked oxygen uptake and peroxide formation. In addition, we have studied the effects of catalase, superoxide dismutase (SOD), and metal ions on the oxygen uptake and peroxide production for MEA in phosphate buffered saline (PBS).
KeywordsOxygen Consumption Oxygen Uptake Oxygen Depletion Peroxide Formation Oxygen Utilization
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