The dediazoniation of p-hydroxybenzenediazonium ion (PDQ) in a neutral aqueous medium has been studied under controlled experimental conditions to prevent photochemical and/or heterolytic side-reactions. Oxygen increased the dediazoniation rate of PDQ and caused the appearance of quinone and hydroquinone. An accumulation of quinone deriving from the reduction of PDQ by hydroquinone was also obs...

UNLABELLED The pathways involved in aromatic compound oxidation under perchlorate and chlorate [collectively known as (per)chlorate]-reducing conditions are poorly understood. Previous studies suggest that these are oxygenase-dependent pathways involving O2 biogenically produced during (per)chlorate respiration. Recently, we described Sedimenticola selenatireducens CUZ and Dechloromarinus chlor...

Much attention has been focused on the role of nitric oxide in hypertension and cardiovascular disease. More recently, the role of superoxide anion and its interaction with nitric oxide has been investigated in this context. This review will concentrate on the role of superoxide in human and experimental hypertension, paying particular attention to the potential sources of superoxide within the...

Idiopathic pulmonary fibrosis (IPF) and chronic obstructive pulmonary disease (COPD) are thought to involve lung injury induced by reactive oxygen species (ROS), in particular superoxide anion. The enzyme, superoxide dismutase (SOD) catalyses the dismutation of superoxide anion to hydrogen peroxide. Lecithinized SOD (PC-SOD) has overcome a number of previous clinical limitations of SOD, includi...

The iron containing superoxide dismutase from E. coli B is shown to catalyze superoxide dismutation by a mechanism which exhibits saturation kinetics. This behavior is quite different from that observed previously with bovine Zn/Cuand iron-containing superoxide dismutase from P. leiosnathi. Two parameters of catalysis were measured in the pH range 7.2 to 10.4: k was found to be independent of p...

The development of experimental acute lung injury following systemic complement activation is closely related to availability of blood neutrophils. Although tissue-destructive neutrophil-derived proteinases may play a supportive role in acute pulmonary injury, it appears that oxygen radical constitute the major neutrophil product responsible for acute damage of lung tissues and cells. Intravasc...

Here, 10 guidelines are presented for a standardized definition of type I and type II photosensitized oxidation reactions. Because of varied notions of reactions mediated by photosensitizers, a checklist of recommendations is provided for their definitions. Type I and type II photoreactions are oxygen-dependent and involve unstable species such as the initial formation of radical cation or neut...

In this study, the effects of UVA and UVB rays on antioxidant enzymes (superoxide dismutase, glutathione peroxidase, catalase) were examined in the corneal epithelium. The corneas of albino rabbits were irradiated with a UV lamp generating UVA (365 nm wavelength) or UVB rays (312 nm wavelength), 1 x daily for 5 min, from a distance of 0.03 m, over 4 days (shorter procedure) or 8 days (longer pr...

Rose Bengal photosensitized flow injection chemiluminescence method is reported using luminol-Cu(II) for the determination of vitamins A and C in pharmaceutical formulations. The reaction is based on the enhancement effect of analyte in the production of anion radicals of Rose Bengal (RB (•-)) which rapidly interact with dissolved oxygen and generate superoxide anions radicals (O2 (•-)) and hyd...