Potent reactive oxygen species

XOR is a cytoplasmic enzyme and a ready source of electrons for transfer to molecular oxygen to form reactive oxygen species such as superoxide and peroxide. It is therefore thought to be involved in free radical-generated tissue injury and has been implicated in the pathogenesis of ischemia-reperfusion damage. Moreover, it has recently been implicated in the production of peroxynitrite (89), and carbonate radical anion (92), both potent biological oxidants. Its exact role in lipid peroxidation, inflammation, and infection needs... 

This ligand has a lower affinity for adenosine A, and A2B receptors with pK values <6. A potent inhibitory effects on the generation of reactive oxygen species from human neutrophils and eosinophils and on the degranulation of human granulocytes subsequent to treatment with compound 30 have been described. This findings provide a useful tool for the understanding of the involvement of A2a and A3 ARs in inflammation processes. 

Nitrilotriacetic acid (NTA) is a constituent of various domestic and hospital detergents and is a common water contaminant. NTA forms water-soluble chelate complexes with various metal ions, including iron, at neutral pH. Its iron complex, Fe-NTA, is a known potent nephrotoxic agent. The renal toxicity is assumed to be caused by the elevation of serum free-iron concentration following the reduction of Fe-NTA at the luminal side of the proximal tubule, which generates reactive oxygen species and leads to enhancement of lipid peroxidation. 

Meier, B Radeke, H.H., Selle, S., Habermehl, G.G., Resch, K Sies, H. (1990). Human fibroblasts release low amounts of reactive oxygen species in response to potent phagocyte stimulants, N-formylmethionylleucylphenylalenine, leukotriene B4 or 12-O-tetradecanoyl phorbol-13-acetate. Biol. Chem. Hoppe Seyler 371,1021-1025. 

The phorbolester phorbol myristate acetate (PMA), which directly activates protein kinase C by bypassing receptor-coupled G-proteins, is the most potent stimulus that produces reactive oxygen species in human eosinophils. This sug-... 

Mediates leukocyte adhesion and activation, allowing them to bind to the endothelium and migrate across it. In neutrophils, a potent chemoattractant and able to induce the formation of reactive oxygen species and the release of lysosomal enzymes by these cells. Potent vasodilator, relaxes smooth muscle, reduces platelet aggregation, aids in leukocyte recruitment, has direct antimicrobial activity in high concentrations. A group of lipids which can cause vasodilation, fever and pain. 

Normal endothelial cells modulate the effects of homocysteine by facilitating the S-nitrosilation of homocysteine by nitric oxide. The formed S-nitrosothiol adduct is a potent vasorelaxing substance [2,108]. So, when high levels of homocysteine occur, they may overcome or impair the endothelial capacity for NO synthesis. Endothelial cell damage may result from increased production of reactive oxygen species or from impaired production of nitric oxide [3,102]. In endothelial cells, total homocysteine reduces the levels of tetra-hydrobiopterin (BH4), relative to dihydrobiopterin (BH ), thereby creating a dysfunctional eNOS causing a reduced amount of nitric oxide [1,101],... 

---