Browsing by Author "Li, Yan"

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    Exaggerated IL-15 and Altered Expression of foxp3+ Cell-Derived Cytokines Contribute to Enhanced Colitis in Nlrp3−/− Mice
    (2016-08-17) Hirota, Simon A.; Ueno, Aito; Tulk, Sarah E.; Becker, Helen M.; Schenck, L. Patrick; Potentier, Mireille S.; Li, Yan; Ghosh, Subrata; Muruve, Daniel A.; MacDonald, Justin A.; Beck, Paul L.
    The pathogenesis of Crohn’s disease (CD) involves defects in the innate immune system, impairing responses to microbes. Studies have revealed that mutations NLRP3 are associated with CD. We reported previously that Nlrp3−/− mice were more susceptible to colitis and exhibited reduced colonic IL-10 expression. In the current study, we sought to determine how the loss of NLRP3 might be altering the function of regulatory T cells, a major source of IL-10. Colitis was induced in wild-type (WT) and Nlrp3−/− mice by treatment with dextran sulphate sodium (DSS). Lamina propria (LP) cells were assessed by flow cytometry and cytokine expression was assessed. DSS-treated Nlrp3−/− mice exhibited increased numbers of colonic foxp3+ T cells that expressed significantly lower levels of IL-10 but increased IL-17. This was associated with increased expression of colonic IL-15 and increased surface expression of IL-15 on LP dendritic cells. Neutralizing IL-15 in Nlrp3−/− mice attenuated the severity of colitis, decreased the number of colonic foxp3+ cells, and reduced the colonic expression of IL-12p40 and IL-17. These data suggest that the NLRP3 inflammasome can regulate intestinal inflammation through noncanonical mechanisms, providing additional insight as to how NLRP3 variants may contribute to the pathogenesis of CD.
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    Identification and Epidemiology of Severe Respiratory Disease due to Novel Swine-Origin Influenza A (H1N1) Virus Infection in Alberta
    (2010-01-01) Zahariadis, George; Joffe, Ari R; Talbot, James; deVilliers, Albert; Campbell, Patricia; Pabbaraju, Kanti; Wong, Sallene; Bastien, Nathalie; Li, Yan; Mitchell, Robyn L; Pang, Xiao-Li; Yanow, Stephanie; Chui, Linda; Predy, Gerald; Willans, David; Lee, Bonita E; Preiksaitis, Jutta K; Clement, Bev; Jacobs, Angela; Jaipaul, Joy; Fonseca, Kevin
    BACKGROUND: In March 2009, global surveillance started detecting cases of influenza-like illness in Mexico. By mid-April 2009, two pediatric patients were identified in the United States who were confirmed to be infected by a novel influenza A (H1N1) strain. The present article describes the first identified severe respiratory infection and the first death associated with pandemic H1N1 (pH1N1) in Canada.METHODS: Enhanced public health and laboratory surveillance for pH1N1 was implemented throughout Alberta on April 24, 2009. Respiratory specimens from all patients with a respiratory illness and travel history or those presenting with a severe respiratory infection requiring hospitalization underwent screening for respiratory viruses using molecular methods. For the first severe case identified and the first death due to pH1N1, histocompatibility leukocyte antigens were compared by molecular methods.RESULTS: The first death (a 39-year-old woman) occurred on April 28, 2009, and on May 1, 2009, a 10-year-old child presented with severe respiratory distress due to pH1N1. Both patients had no travel or contact with anyone who had travelled to Mexico; the cases were not linked. Histocompatibility antigen comparison of both patients did not identify any notable similarity. pH1N1 strains identified in Alberta did not differ from the Mexican strain.CONCLUSION: Rapid transmission of pH1N1 continued to occur in Alberta following the first death and the first severe respiratory infection in Canada, which were identified without any apparent connection to Mexico or the United States. Contact tracing follow-up suggested that oseltamivir may have prevented ongoing transmission of pH1N1.
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    Solution Based Synthesis of Copper Nanowire/Polymer Composites and Their Electrical Properties
    (2014-01-29) Li, Yan; Sundararaj, Uttandaraman
    Conductive polymer composites (CPCs) are intensively researched partly because of their advantages in acting as conductive materials while maintaining polymers’ properties such as easy processability, corrosion resistance and light weight. This thesis focuses on using copper nanowires (CuNW) as filler, with different polymers as matrices, in order to study the influence of filler loading, the interaction between filler and matrix on the electrical properties and the electromagnetic interference shielding properties of the composites. CPCs with CuNW as filler and different polymers as matrices were successfully prepared using miscible solution mixing and precipitation method. Among these composites, copper nanowire/polypropylene (CuNW/PP) composite is investigated primarily and compared with carbon nanotube/polypropylene composite. The conductivity curve of CuNW/PP composite shows a different trend than typical percolation, where a plateau was found around CuNW concentration between 0.8 vol. % and 1.7 vol. %. Further study regarding synthesis of CuNW is also reported.