Oxidant sensitive promoters

Mediators of both the infiammatoiy and fibrotic responses have been associated with exposure to oxidants. Similarly, mediator release after incubation of cells with silica and asbestos can be the result of oxygen-based free radicals catalyzed by iron associated with the mineral oxide (Fig. 1). The increase in arachidonic acid metabolism after exposures of cells to particles and fibers can result from the eooxidation of arachidonate by metal-catalyzed oxidants. This is a lipid peroxidation that can be mediated by free radical production by the dust (83). In support of an association between metal-catalyzed oxidant generation and arachidonic acid products, the release of LTB4 by alveolar macrophages can increase with the eoneentrations of iron complexed to the surface of silica and asbestos (84). Similarly, the eellular release of eytokines postulated to participate in the infiammatory and fibrotic responses ean be associated with exposures to metal-dependent radicals (see Fig. 1). TNF-a produetion by alveolar macrophages after mineral oxide exposure can be inhibited by both the metal chelator deferoxamine and hydroxyl radical scavengers (74). The release of other cytokines pertinent to silica and asbestos exposure ean also be responsive to oxidative stress (85,86). The release of these pertinent mediators after dust exposures is likely to be controlled by oxidant-sensitive promoters such as nuclear factor (NF)-kB (87). After exposure to silica and asbestos, NF-kB can function as a promoter... 

Figure 1 Schematic of an association between mediator release after silica and asbestos exposure and metal-catalyzed oxidant generation by the partieles Eieosanoid production can result from a co-oxidation of arachidonate by metal-catalyzed oxidants generated by the partieles. Similarly, the release of other cytokines pertinent to siliea and asbestos exposure can be responsive to oxidant-sensitive promoters.

Yamaura H, Moriya K, Miura N, Yamazoe N (2000) Mechanism of sensitivity promotion in CO sensors using indium oxide and cobalt oxide. Sens Actuators B 65 39-41... 

Xu C, Lai X, Zajac GW, Goodman DW (1997) Scanning tunneling microscopy studies of the liO fllO) surface structure and the nucleation growth of Pd. Phys Rev 56 13464-13482 Yamaura H, Moriya K, Miura N, Yamazoe N (2000) Mechanism of sensitivity promotion in CO sensors using indium oxide and cobalt oxide. Sens Actuators B 65 39-41... 

It is known that not all reactions proceed in the same manner on all adsorbent layers because the material in the layer may promote or retard the reaction. Thus, Ganshirt [209] was able to show that caffeine and codeine phosphate could be detected on aluminium oxide by chlorination and treatment with benzidine, but that there was no reaction with the same reagent on silica gel. Again the detection of amino acids and peptides by ninhydrin is more sensitive on pure cellulose than it is on layers containing fluorescence indicators [210]. The NBP reagent (. v.) cannot be employed on Nano-Sil-Ci8-100-UV2S4 plates because the whole of the plate background becomes colored. 

The very first studies with radiation crosslinked polyethylene oxide (PEO) have shown that SAH is able to substantially reduce the sensitivity of plants to water shortage [7], to promote their growth, particularly, under conditions of water deficiency [8], to improve seedling survival and the final crop [9], These results stimulated a more detailed analysis of the effects of SAH in the water balance of... 

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