University of Seville

About: University of Seville is a education organization based out in Seville, Andalucía, Spain. It is known for research contribution in the topics: Population & Model predictive control. The organization has 20098 authors who have published 47317 publications receiving 947007 citations. The organization is also known as: Universidad de Sevilla.

Vasoactive intestinal peptide and pituitary adenylate cyclase-activating polypeptide inhibit endotoxin-induced TNF-alpha production by macrophages: in vitro and in vivo studies.

Abstract: Vasoactive intestinal peptide (VIP) is a neuropeptide synthesized by immune cells that can modulate several immune aspects, including the function of cells involved in the inflammatory response, such as macrophages and monocytes. The production and release of cytokines by activated phagocytes are important events in the pathogenesis of ischemia-reperfusion injury. There is abundant evidence that the proinflammatory cytokine TNF-α is an important mediator of shock and organ failure complicating Gram-negative sepsis. VIP has been shown to attenuate the deleterious consequences of this pathologic phenomenon. In this study we have investigated the effects of VIP and the structurally related neuropeptide pituitary adenylate cyclase-activating polypeptide (PACAP38) on the production of TNF-α by endotoxin-activated murine peritoneal macrophages. Both neuropeptides rapidly and specifically inhibit the LPS-stimulated production of TNF-α, exerting their action through the binding to VPAC1 receptor and the subsequent activation of the adenylate cyclase system. VIP and PACAP regulate the production of TNF-α at a transcriptional level. In vitro results were correlated with an inhibition of both TNF-α expression and release in endotoxemic mice in vivo. The immunomodulatory role of VIP in vivo is supported by the up-regulation of VIP release in serum and peritoneal fluid by LPS and proinflammatory cytokines such as TNF-α, IL-1β, and IL-6. These findings support the idea that under toxicity conditions associated with high LPS doses, VIP and PACAP could act as protective mediators that regulate the excessive release of TNF-α to reduce inflammation or shock.

Reaction of NH3 with titania: N-doping of the oxide and TiN formation

Abstract: The thermal nitridation of titania powder (anatase and P25) by reaction with ammonia has been investigated by in-situ reaction studies and ex-situ characterizations using X-ray photoelectron spectroscopy (XPS), near-edge X-ray absorption fine structure (NEXAFS), and X-ray diffraction (XRD). At temperatures below 750 °C, the formation of TiN from the reaction of NH3 with the titania sample was negligible. Above 750 °C, in-situ reaction studies using XRD revealed a smooth phase transition from anatase or P25 to cubic TiN. On the basis of comprehensive characterizations, the crystalline structure of nitrogen-doped TiO2 is in general similar to that of TiO2. Incorporation of nitrogen into the interstitial sites of TiO2 anatase is supported by Rietveld refinement of XRD data. Interstitial nitrogen may form N2-like species bound to either oxygen vacancies or the cavity-framework atoms with various degrees of bond strength. N 1s XPS and N K-edge NEXAFS spectra support the idea that nitrogen present in titania as...