http://www.researchonline.mq.edu.au/vital/access/services/Feed ${session.getAttribute("locale")} 5 http://www.researchonline.mq.edu.au/vital/access/manager/Repository/mq:5985 Oxidation of polyunsaturated fatty acids by thiyl radicals derived from GSH or Cys is believed to be responsible for some of the biological damage resulting from lipid oxidation under oxidative stress. However, this has not been demonstrated in complex biological systems. In this study, we measured the formation of lipid hydroperoxides in liposomes exposed to radicals generated by γ radiation from GSH, GSSG, GSMe, Cys and Met. In the absence of proteins, the radicals oxidized the liposome lipids. In the presence of proteins, the thiyl radicals failed to react with the liposomes, even though the protein radicals efficiently oxidized the S-compounds. It appears that the thiyl and other S-radicals were effectively scavenged by the protein before initiating lipid oxidation. The results suggest that membrane lipid oxidation in vivo by thiyl radicals is unlikely to be a significant event. 2010-01-27T22:23:40.890Z ]]> http://www.researchonline.mq.edu.au/vital/access/manager/Repository/mq:6912 The effect of olmesartan, an inverse angiotensin II type 1 receptor blocker (ARB), on oxidative stress in hemodialysis (HD) patients is not fully understood, and has not been widely investigated in vitro or in vivo. We determined the amount of oxidized albumin and albumin hydroperoxides formed during incubation in the absence and presence of olmesartan by high-performance liquid chromatography (HPLC) and by a ferrous oxidation xylenol assay in an in vitro study. Six hypertensive HD patients were treated with 40 mg of olmesartan once daily, and blood pressure monitoring (BPM) was performed after 0, 4, and 8 weeks of treatment. The ratio of oxidized to unoxidized albumin was also determined. The oxidized albumin ratios and levels of albumin hydroperoxides were significantly decreased in a concentration-dependent manner in the presence of olmesartan, compared with the absence of olmesartan (p<0.05) in in vitro studies. In HD patients, olmesartan also significantly reduced systolic and diastolic blood pressure after 4 weeks, with a further significant decrease after 8 weeks. The ratio of oxidized to unoxidized albumin was markedly decreased after 4 weeks and these lower levels were maintained at 8 weeks. Olmesartan effectively lowered the extent of oxidation of albumin in both in vitro and in vivo studies, and this effect might confer benefits beyond a reduction in blood pressure. 2010-01-27T22:11:39.612Z ]]>