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While it has been suggested that IL-33 plays pathogenic roles in various disorders, the factors that stimulate IL-33 production are poorly characterized. In the present study, the effect of cyclic adenosine monophosphate (cAMP) signaling on IL-33 production in RAW264.7 macrophages in response to various doses of LPS was examined. High-dose LPS treatment induced IL-33 and TNF protein production in RAW264.7 macrophages. In contrast, low-dose LPS failed to induce IL-33 production while significantly inducing TNF production. In the presence of the membrane-permeable cAMP analog 8-Br-cAMP, low-dose LPS induced vigorous IL-33 production. This phenomenon was consistent with amounts of mRNA. Similarly, the cAMP-increasing agent adrenaline also enhanced the sensitivity of RAW264.7 macrophages to LPS as demonstrated by IL-33 production. The protein kinase A (PKA) inhibitor H89 blocked the effects of 8-Br-cAMP and adrenaline on IL-33 production, suggesting that PKA is involved in IL-33 induction. Taken together, cAMP-mediated signaling pathway appears to enhance the sensitivity of RAW264.7 macrophages to LPS with respect to IL-33 production. Our findings suggest that stress events and the subsequent secretion of adrenaline enhance macrophage production via IL-33; this process may be associated with the pathogenesis of various disorders involving IL-33.

AgBr-doped silsesquioxane–titania films with a thickness of approximately 5 μm were prepared using a sol–gel technique. The dopant AgBr crystals were converted into very small Ag nanoparticles (mainly several nanometers) upon blue laser irradiation, leading to an increase in the absorption of the film in the visible region. An excess of Ag + ions in the film was required for the conversion of AgBr into Ag upon blue laser irradiation. A maximum diffraction efficiency of 0.03% was achieved after two-beam interference exposure with a blue laser for 1300 s. These results imply that the films are suitable for use as holographic materials.

Photoinduced reduction, resulting in nanoparticle formation, and heat-induced oxidation of doped silver have been demonstrated in silsesquioxane (RSiO(3/2)) and RSiO(3/2)-TiO(2) films (R = methyl, vinyl, and glycidoxypropyl) synthesized via the sol-gel method. The occurrence of redox behavior in the doped silver, i.e. formation and dissociation of silver nanoparticles (AgNPs) in the films, was confirmed by UV-Vis spectroscopy, IR spectroscopy, X-ray diffraction and transmission electron microscopy. The films containing vinyl and glycidoxypropyl organic functional groups were found to effectively reduce silver ions upon UV irradiation, whereas the film containing the methyl group substituent did not. Incorporation of a TiO(2) component into the RSiO(3/2) films caused thermal dissociation of the AgNPs. The formation and dissociation of AgNPs in the films was reversible by reiterating the cycle of UV irradiation and heat treatment.