Characterization by Electron Spin Resonance Spectroscopy of Reactive Oxygen Species Generated by Titanium Dioxide and Hydrogen Peroxide

Sialic acid is an essential moiety of mucin as a hydroxyl radical scavenger

In this work, we examined the antioxidant role of mucin, a typical sialic acid containing high-molecular weight glycoprotein. The function of mucin as a hydroxyl radical (.OH) scavenger was characterized using bovine submaxillary gland mucin (BSM). Non-treated BSM effectively protected DNA from the attack of .OH; however, desialylated BSM lost this potential. Moreover, we estimated the scavenging effects of BSM against .OH generated by UV irradiation of hydrogen peroxide using ESR analysis. Our results indicate that BSM has .OH scavenging ability the and sialic acid in mucin is an essential moiety to scavenge .OH.

Reactive oxygen and nitrogen species: Implications for cardiovascular device engineering

The development of medical devices for cardiovascular applications has suffered due to lack of understanding of why vascular wall cells act nonphysiologically when exposed to biomaterials. One possible reason might be the chemical environment associated with cardiovascular disease. An improved understanding of cellular and subcellular mechanisms may assist in future device design to account for the disease environment. Reactive oxygen and nitrogen species (ROS/RNS) are produced through normal cellular metabolism and are rendered harmless by enzymatic systems. However, during a disease process, these systems may act aberrantly, and either fail to convert ROS and RNS to harmless substances or by producing more oxidants. There is indirect evidence that the implantation of biomedical materials may also be responsible for the triggering of these aberrant pathways that may lead to the eventual failure of the device. The understanding of how the vascular environment may be changed at the subcellular level by the presence of a biomaterial is critical. In the following pages, we hope to review the current thinking within vascular biology regarding ROS and RNS, how they are measured, and how they may impact vascular cells.

Reactive oxygen species generation in gingival fibroblasts of Down syndrome patients detected by electron spin resonance spectroscopy

Oral manifestations of Down syndrome include high susceptibility to gingival inflammation with early onset and rapidly progressive periodontitis. The influence of reactive oxygen species (ROS) on periodontitis of Down syndrome is unclear. The aim of this study was to characterize ROS formation in Down syndrome-gingival fibroblasts (DS-GF) using electron spin resonance (ESR) spin trapping with 5,5-dimetyl-1-pyrolline-N-oxide (DMPO), and to determine whether ROS generation plays a role in the pathogenesis of periodontitis in Down syndrome patients. We observed formation of the DMPO-OH spin adduct, indicating HO* generation from cultured DS-GF and non-DS-GF. The increased HO* generation in cultured DS-GF was strongly decreased in the presence of the H2O2 scavenger, catalase, or the iron chelator, desferal. This may due to the enzymatic ability of over-expressed CuZn-superoxide dismutase in Down syndrome to catalyze the formation of H2O2 from O2*-, thereby increasing the availability of substrate H2O2 for the iron-dependent generation of HO* via the Fenton reaction, suggesting that HO* generated from DS-GF may be involved in progressive periodontitis of Down syndrome.