The antiviral effects of nitric oxide (NO) on Japanese encephalitis virus (JEV), a member of the family Flaviviridae, were investigated in this study. In vitro, inhibition of replication of JEV in gamma interferonactivated RAW 264.7 murine macrophages was correlated to cellular NO production. When cocultured with infected murine neuroblastoma N18 cells, gamma interferon-activated RAW 264.7 cells also efficiently hindered JEV replication in contiguous bystanders, and this anti-JEV effect could be reversed by an NO synthase (NOS) inhibitor, N-monomethyl-L-arginine acetate. In vivo, the mortality rate increased as the NOS activity of JEV-infected mice was inhibited by its competitive inhibitor, N-nitro-L-arginine methyl ester. Moreover, when an organic donor, S-nitro-N-acetylpenicillamine (SNAP), was used, the NO-mediated antiviral effect was also observed in primarily JEV-infected N18, human neuronal NT-2, and BHK-21 cells, as well as in persistently JEV-infected C2-2 cells. These data reaffirm that NO has an effective and broad-spectrum antimicrobial activity against diversified intracellular pathogens. Interestingly, the antiviral effect of NO was not enhanced by treatment of N18 cells with SNAP prior to JEV infection, a measure which has been shown to greatly increase the antiviral effect of NO in infection by vesicular stomatitis virus. From biochemical analysis of the impact of NO on JEV replication in cell culture, NO was found to profoundly inhibit viral RNA synthesis, viral protein accumulation, and virus release from infected cells. The results herein thus suggest that NO may play a crucial role in the innate immunity of the host to restrict the initial stage of JEV infection in the central nervous system.
The effect of nitric oxide (NO) donors and lipopolysaccharide (LPS) on the proliferation of rat glomerular mesangial cells was characterized. Exogenous application of a NO donor inhibited serum-induced proliferation in a time-and dose-dependent manner. S-Nitrosoglutathione (GSNO) also increased cGMP generation and arachidonic acid release, but it did not cause any measurable increase in the cytosolic Ca 2þ concentration. Chelation of cytosolic Ca 2þ or inhibition of mitogen-activated protein kinase (MAPK) kinase had an inhibitory effect on proliferation, but neither enhanced the antiproliferative effect of GSNO. In contrast, inhibition of guanylate cyclase or phospholipase A 2 had no effect on proliferation, but partially reversed GSNO-induced antiproliferation by < 98 and 65%, respectively. GSNO did not cause cell death. Incubation of cells with LPS induced endogenous NO generation and had an antiproliferative effect. LPS-induced antiproliferation was reversed completely by inhibition of nitric oxide synthase and partially by inhibition of guanylate cyclase or phospholipase A 2 . GSNO or LPS inhibited serum-induced MAPK activation, and both effects were partially reversed by inhibition of guanylate cyclase or phospholipase A 2 . Inclusion of 8-bromo-cGMP or arachidonic acid in the growth medium resulted in a similar antiproliferative effect. In conclusion, in rat glomerular mesangial cells, MAPK inhibition and an antiproliferative effect could be induced by either an increase in the cellular concentration of NO or exposure of the cells to LPS. Part of the effect of NO was attributable to the increased cellular cGMP generation and arachidonic acid release.
Decision-making processes in traditional urban design approaches are mainly top-down. Such processes have defects including not only taking a long time to examine design results but also leading to irreversible impacts after design implementation. Policymakers and researchers stress the importance of collaborating with different stakeholders in the process of urban design policy and guideline making in order to minimize these negative impacts. However, introducing public participation into urban design from the bottom up is challenging, especially when the process involves abstract urban design concepts such as indicators. This paper explores a new workflow aimed at enhancing public participation to cooperate in urban design work with the help of a newly designed platform tool powered by mobile augmented-reality technologies. The platform is intuitive to use and displays scenes of potential urban design results by superimposing the virtual models onto real-world environments on mobile devices. The public stakeholders are provided with this platform on-site to evaluate the initial values of urban design indicators by interacting with the prototype design along with an immersive experience. They can also grow familiar with the concepts of the given indicators during this process, which helps them better understand the implications of guidelines in future published urban design drafts and estimate the potential results. Their feedback is collected, which can help urban designers further optimize the indicators in urban design guideline making in order to improve their rationality. This process of urban design involving public participation is repeatable, which makes it possible to continuously adjust the design results. A user study was conducted to examine the platform’s usability and its ability to enhance public familiarity with the concepts of given indicators and their willingness to participate in urban design evaluation. The study also attests to the possibility of a workflow that integrates public feedback with the urban design process.
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