scopes may cause chemical colitis [1–3]. However, it remains controversial whether the agent reponsible is the peracetic acid or the hydrogen peroxide in the solution. We recently encountered four cases of chemical colitis, showing characteristic morphologic and histologic features, including the “snow white sign”, following use of a new automated disinfection device in our endoscopy unit. The ...

OBJECTIVE This study evaluated the effects of carbamide peroxide and hydrogen peroxide on the biaxial flexural strength and flexural modulus of bovine dentin. MATERIALS AND METHODS Thirty coronal dentin disks (0.5 mm thick × 6.0 mm diameter) were prepared from bovine teeth. The disks were randomly divided into three groups (n=10): A control group (unbleached), a group bleached with 10% carbam...

⎯Hydrogen, oxygen, and hydrogen peroxide have been measured downstream of an atmospheric pressure humid argon dielectric barrier discharge. The yield of the three species was studied as a function of the discharge power and gas flow rate. Hydrogen peroxide was measured after dissolution into water downstream of the discharge, while hydrogen and oxygen were measured in the gas phase. The product...

BACKGROUND The tooth whitening substances for extrinsic use that are available in Brazil contain hydrogen peroxide or carbamide peroxide. Several studies have attributed the appearance of lesions in the enamel morphology, including hypersensitivity, to these substances. Such lesions justify fluoride therapy and application of infrared lasers, among other procedures. However, there is no consens...

PURPOSE Iron plays a central role in the oxidative stress caused by hydrogen peroxide. The ubiquitous iron storage protein, ferritin, safely sequesters iron, reducing its ability to cause oxidative damage. Oxidative stress can activate mitogen-activated protein (MAP) kinase pathways with many downstream effects. The purpose of this study was to determine the effects of hydrogen peroxide on MAP ...

BspA is an abundant surface protein from Lactobacillus fermentum BR11, and is required for normal cystine uptake. In previous studies, a mutant strain deficient in BspA (L. fermentum PNG201) was found to be sensitive to oxidative stress. In this study, the biochemical basis for this was explored. It was found that under aerobic batch culture conditions in de Mann-Rogosa-Sharpe medium, both L. f...

Hydrogen peroxide is formed in solutions of glutathione exposed to oxygen. This hydrogen peroxide or its precursors will decrease the viscosity of polymers like desoxyribonucleic acid and sodium alginate. Further knowledge of the mechanism of these chemical effects of oxygen might further the understanding of the biological effects of oxygen. This study deals with the rate of solution of oxygen...

Hydrogen peroxide is a very reactive byproduct of many metabolic pathways. We describe an ultra-sensitive colorimetric method to detect hydrogen peroxide based on the reconstitution of apo-horseradish peroxidase with the hemin derivative, hemin di(N,N'-acetyl-hydrazide). Oxidation of the latter by hydrogen peroxide yields hemin, which is able to reconstitute apo-horseradish peroxidase, forming ...

Reactive oxygen intermediates (ROIs) are among the important mediators in the pathogenesis of lung diseases in which tumor necrosis factor (TNF) plays a pivotal role. However, the effects of ROIs on the TNF- TNF receptor system remain unclear. Effects of hydrogen peroxide on the shedding of soluble tumor necrosis factor receptor (sTNF-R) were investigated in a pulmonary epithelial cell line (A5...

Peroxiredoxins (Prdxs), a family of antioxidant and redox-signaling proteins, are plentiful within the heart; however, their cardiac functions are poorly understood. These studies were designed to characterize the complex changes in Prdxs induced by oxidant stress in rat myocardium. Hydrogen peroxide, a Prdx substrate, was used as the model oxidant pertinent to redox signaling during health and...