bacteria! plaque is an essential factor of gingival and periodontal disease.the ability of chemical piaque control agent to prevent plaque formation is well documented compare with other mechanical plaque removal methods. the purpose of this study was to compare clinical effects of shore choice mouth rinse (h2 o2, 0.1%) with a placebo.following a period of 4 weeks, 20 subjects were allocated to...

We recently developed a mathematical model for predicting reactive oxygen species (ROS) concentration and macromolecules oxidation in vivo. We constructed such a model using Escherichia coli as a model organism and a set of ordinary differential equations. In order to evaluate the major defences relative roles against hydrogen peroxide (H2 O2), we investigated the relative contributions of the ...

Despite insufficient laboratory data, radiotherapy after intratumoral injection of hydrogen peroxide (H2 O2 ) is increasingly being used clinically for radioresistant tumors. Especially, this treatment might become an alternative definitive treatment for early and advanced breast cancer in patients who refuse any type of surgery. The purpose of this study was to investigate the biological effec...

BACKGROUND Hydrogen peroxide (H2 O2 ) is the cosubstrate used by the enzyme catalase to form Compound I (the catalase-H2 O2 system), which is the major pathway for the conversion of ethanol (EtOH) into acetaldehyde in the brain. This centrally formed acetaldehyde has been shown to be involved in some of the psychopharmacological effects induced by EtOH in rodents, including voluntary alcohol in...

We have discovered a new competitive pathway for O2 sensitivity in algal H2 production that is distinct from the O2 sensitivity of hydrogenase per se. This O2 sensitivity is apparently linked to the photosynthetic H2 production pathway that is coupled to proton translocation across the thylakoid membrane. Addition of the proton uncoupler carbonyl cyanide-p-trifluoromethoxy- phenylhydrazone elim...

The Earth’s early environment was relatively poor in oxygen, and observations and modeling indicate that the rise in oxygen levels did not occur until long after oxygen-enriching bacterial photosynthesis had developed. Catling et al. (p. 839; see the Perspective by Kasting) explain the apparent disconnect between oxygenation and the start of photosynthesis by adding methanogenesis to the proces...

The methylmenaquinol:fumarate reductase (Mfr) of Campylobacter jejuni is a periplasmic respiratory (redox) protein that contributes to the metabolism of fumarate and displays homology to succinate dehydrogenase (Sdh). Since chemically oxidized redox-enzymes, including fumarate reductase and Sdh, contribute to the generation of oxidative stress in Escherichia coli, we assessed the role of Mfr in...

BACKGROUND We have previously shown that hydrogen (H2) inhalation, begun at the start of hyperoxic cardiopulmonary resuscitation, significantly improves brain and cardiac function in a rat model of cardiac arrest. Here, we examine the effectiveness of this therapeutic approach when H2 inhalation is begun on the return of spontaneous circulation (ROSC) under normoxic conditions, either alone or ...

In the hierarchical development of kinetic mechanisms for large hydrocarbons, the reaction systems involving C1 species represent the next level of complexity beyond the thoroughly studied reactions of H2/O2 mixtures. Encompassing our recently updated H2/O2 mechanism (Li et al., Int. J. Chem. Kinet, submitted), we have revisited the CO/H2/O2, CH2O/O2, and CH3OH/O2 systems, considering recent ki...