Hydrogen peroxide, adverse effects

Metal-ion catalysis of hydrogen peroxide decomposition can generate perhydroxyl and hydroxyl free radicals as in Scheme 10.26 [235]. The catalytic effects of Fe2+ and Fe3+ ions are found to be similar [235]. It is not necessary for the active catalyst to be dissolved [237], as rust particles can be a prime cause of local damage. The degradative free-radical reaction competes with the bleaching reaction, as illustrated in Scheme 10.27 [237]. Two adverse consequences arise from the presence of free radicals ... 

A method of separation which avoids the preparation of the double fluorides consists in fusing the mixed niobic and t an tali c acids with sodium carbonate and nitrate, the product is digested with warm water and a current of carbon dioxide is passed through the solution. It is claimed that only tantalic acid is precipitated.5 This process has, however, been the subject of adverse criticism.6 Partial separation of niobium from tantalum can be effected by warming the mixed, freshly precipitated, hydrated oxides with a mixture of hydrogen peroxide and hydrochloric acid the niobium dissolves readily, while the tantalum dissolves only sparingly.7... 

There is not room here to discuss the detailed mechanisms by which exposure to radiation causes adverse responses. Much of the effects of radiation result from its interaction with water to produce active species that include superoxide (Oi), hydroxyl radical (HO-), hydroperoxyl radical (HOO), and hydrogen peroxide (H202). These species oxidize cellular macromolecules. When DNA is so affected, mutagenesis and carcinogenesis may result. Ionizing radiation can also interact with organic substances to produce a carbonium ion, such as +CH3, that can alkylate nitrogenous bases on DNA. 

Imidazoles (ketoconazole, miconazole, fenticonazole, clotrimazole, isoconazole, tioconazole) interfere with fungal oxidative enzymes to cause lethal accumulation of hydrogen peroxide they also reduce the formation of ergosterol, an important constituent of the fungal cell wall which thus becomes permeable to intracellular constituents. Lack of selectivity in these actions results in important adverse effects. 

The PPARa Activator MOA Is Chemical-Independent. Mode of action is a series of key events that together result in an adverse health effect such as a liver tumor and as such is chemical-independent (Boobis et al. 2008 Holsapple et al. 2006 Meek 2008). Consistent with this the MOA for PPARa activators is an endogenous series of events that can occur independent of chemical exposure. Livers from ACO-nuU mice exhibit severe steatosis, increases in markers of PPARa activation (i.e., genes involved in P- and co-fatty acid oxidation), increases in hydrogen peroxide levels, increases in ceU proliferation and fiver tumors (Fan et al. 1998). The increases in the markers of PPARa were shown to be PPARa-dependent as the changes were abolished in a double ACO-/PPARa-null mouse (Hashimoto et al. 

Lee and Chu also reported that the addition of Fenton agent or hydrogen peroxide to the degradation medium would retard the well-known adverse effect of the conventional y-irradiation sterilization of synthetic absorbable sutures [Lee et al., 1996a]. They found that these y-irradiated sutures retained better tensile breaking strength in the Fenton medium than in the regular buffer media. Chu et al. postulated that the y-irradiation induced a-carbon radicals in these sutures react with the hydroxyl radicals from... 

Hydrogen peroxide vapor (HPV) is used for decontamination of BSCs. It is effective against a wide range of bacteria, viruses, and fungi. Equipment such as computers, complex instruments, and electronic parts are not adversely affected by HPV and there is no residue from its use. Generation of HPV requires special equipment and careful placement of units to ensure adequate decontamination. However, it is an environmentally friendly disinfectant since its products are oxygen and water. 

---