Insight on the fundamentals of advanced oxidation processes. Role and review of the determination methods of reactive oxygen species

Advanced oxidation processes (AOPs) have known increased application to treat wastewaters containing recalcitrant compounds that are hardly degraded by conventional technologies. AOPs are characterized by the formation of strong oxidants such as hydroxyl radicals, superoxide anions, hydroperoxyl radicals and singlet oxygen, which react with the contaminant, contributing to its degradation. This paper provides an overview of the determination methods of reactive oxygen species, ROS, in the application of AOPs; the methods developed in the available literature for the detection and quantification of ROS are reviewed as a first step in the assessment and detailed description of the mechanisms involved in the oxidation reactions, focusing on the critical analysis of the main strengths and weaknesses presented by the probe molecules employed in the evaluated studies.This research was supported by the Ministry of Economy and Competitiveness (MINECO/SPAIN) and European Regional Development Fund (ERDF) under the project CTQ2011-25262

Regional heterogeneity of functional changes in conduit arteries after high-fat diet

OBJECTIVE: To determine effects of dietary fat content on vascular responses in different conduit arteries in mice. METHODS AND PROCEDURES: Vascular responses to reactive oxygen species (ROS)/hydroxyl radical (.OH), acetylcholine (ACh), endothelin-1 (ET-1), and angiotensin II (Ang II) were determined in carotid and femoral arteries of C57BL/6J mice fed with diets varying in fat content (low fat (LF), 12.3%; high fat (HF), 41%; and very high fat (VHF), 58% (kcal from fat)) for 15 weeks, beginning at 4 weeks of age. RESULTS: In precontracted rings of carotid and femoral artery, ROS/.OH-induced a rapid, transient vasodilation. In the carotid, but not in femoral artery, ROS/.OH-induced dilation increased with increasing dietary fat intake (P < 0.05 vs. LF diet), while contractile responses to ROS/.OH remained unaffected. In femoral arteries, ROS/.OH-induced contractions were reversed into relaxations after both HF and VHF diet (P < 0.05 vs. LF diet). Both ET-1 and Ang II induced strong contractions in the femoral artery that were unaffected by dietary fat intake. In contrast, in the carotid artery Ang II-induced contraction was attenuated after HF and VHF diets (P < 0.005 vs. LF diet), whereas ET-1-induced vasoconstriction was significantly increased (P < 0.05 VHF vs. LF and HF). Treatment with VHF diet enhanced ACh-mediated endothelium-dependent relaxation only in the femoral artery (P < 0.05 vs. HF). DISCUSSION: These findings demonstrate that dietary fat content has regional and distinct effects on vascular function in different vascular beds. The data also suggest the possibility that in selected conduit arteries ROS-dependent vasodilator mechanisms become activated in response to increased dietary fat intake