Angiotensin II Requires Zinc and Downregulation of the Zinc Transporters ZnT3 and ZnT10 to Induce Senescence of Vascular Smooth Muscle Cells

Senescence, a hallmark of mammalian aging, is associated with the onset and progression of cardiovascular disease. Angiotensin II (Ang II) signaling and zinc homeostasis dysfunction are increased with age and are linked to cardiovascular disease, but the relationship among these processes has not been investigated. We used a model of cellular senescence induced by Ang II in vascular smooth muscle cells (VSMCs) to explore the role of zinc in vascular dysfunction. We found that Ang II-induced senescence is a zinc-dependent pathway mediated by the downregulation of the zinc transporters ZnT3 and ZnT10, which work to reduce cytosolic zinc. Zinc mimics Ang II by increasing reactive oxygen species (ROS), activating NADPH oxidase activity and Akt, and by downregulating ZnT3 and ZnT10 and inducing senescence. Zinc increases Ang II-induced senescence, while the zinc chelator TPEN, as well as overexpression of ZnT3 or ZnT10, decreases ROS and prevents senescence. Using HEK293 cells, we found that ZnT10 localizes in recycling endosomes and transports zinc into vesicles to prevent zinc toxicity. Zinc and ZnT3/ZnT10 downregulation induces senescence by decreasing the expression of catalase. Consistently, ZnT3 and ZnT10 downregulation by siRNA increases ROS while downregulation of catalase by siRNA induces senescence. Zinc, siZnT3 and siZnT10 downregulate catalase by a post-transcriptional mechanism mediated by decreased phosphorylation of ERK1/2. These data demonstrate that zinc homeostasis dysfunction by decreased expression of ZnT3 or ZnT10 promotes senescence and that Ang II-induced senescence is a zinc and ROS-dependent process. Our studies suggest that zinc might also affect other ROS-dependent processes induced by Ang II, such as hypertrophy and migration of smooth muscle cells

A preliminary randomized double blind placebo-controlled trial of intravenous immunoglobulin for Japanese encephalitis in Nepal

BACKGROUND: Japanese encephalitis (JE) virus (JEV) is a mosquito-borne flavivirus found across Asia that is closely related to West Nile virus. There is no known antiviral treatment for any flavivirus. Results from in vitro studies and animal models suggest intravenous immunoglobulin (IVIG) containing virus-specific neutralizing antibody may be effective in improving outcome in viral encephalitis. IVIG's anti-inflammatory properties may also be beneficial. METHODOLOGY/PRINCIPAL FINDINGS: We performed a pilot feasibility randomized double-blind placebo-controlled trial of IVIG containing anti-JEV neutralizing antibody (ImmunoRel, 400mg/kg/day for 5 days) in children with suspected JE at two sites in Nepal; we also examined the effect on serum neutralizing antibody titre and cytokine profiles. 22 children were recruited, 13 of whom had confirmed JE; 11 received IVIG and 11 placebo, with no protocol violations. One child (IVIG group) died during treatment and two (placebo) subsequently following hospital discharge. Overall, there was no difference in outcome between treatment groups at discharge or follow up. Passive transfer of anti-JEV antibody was seen in JEV negative children. JEV positive children treated with IVIG had JEV-specific neutralizing antibody titres approximately 16 times higher than those treated with placebo (p=0.2), which was more than could be explained by passive transfer alone. IL-4 and IL-6 were higher in the IVIG group. CONCLUSIONS/SIGNIFICANCE: A trial of IVIG for JE in Nepal is feasible. IVIG may augment the development of neutralizing antibodies in JEV positive patients. IVIG appears an appealing option for JE treatment that warrants further study. TRIAL REGISTRATION: ClinicalTrials.gov NCT01856205

The development, design, testing, refinement, simulation and application of an evaluation framework for communities of practice and social-professional networks

Background. Communities of practice and social-professional networks are generally considered to enhance workplace experience and enable organizational success. However, despite the remarkable growth in interest in the role of collaborating structures in a range of industries, there is a paucity of empirical research to support this view. Nor is there a convincing model for their systematic evaluation, despite the significant potential benefits in answering the core question: how well do groups of professionals work together and how could they be organised to work together more effectively? This research project will produce a rigorous evaluation methodology and deliver supporting tools for the benefit of researchers, policymakers, practitioners and consumers within the health system and other sectors. Given the prevalence and importance of communities of practice and social networks, and the extent of investments in them, this project represents a scientific innovation of national and international significance. Methods and design. Working in four conceptual phases the project will employ a combination of qualitative and quantitative methods to develop, design, field-test, refine and finalise an evaluation framework. Once available the framework will be used to evaluate simulated, and then later existing, health care communities of practice and social-professional networks to assess their effectiveness in achieving desired outcomes. Peak stakeholder groups have agreed to involve a wide range of members and participant organisations, and will facilitate access to various policy, managerial and clinical networks. Discussion. Given its scope and size, the project represents a valuable opportunity to achieve breakthroughs at two levels; firstly, by introducing novel and innovative aims and methods into the social research process and, secondly, through the resulting evaluation framework and tools. We anticipate valuable outcomes in the improved understanding of organisational performance and delivery of care. The project's wider appeal lies in transferring this understanding to other health jurisdictions and to other industries and sectors, both nationally and internationally. This means not merely publishing the results, but contextually interpreting them, and translating them to advance the knowledge base and enable widespread institutional and organisational application

Physical stem-end treatment effects on cut rose and acacia vase life and water relations

Cut Rosa hybrida cv. High & Mighty flowers and Acacia holosericea (Velvet Leaf Wattle) foliage were subjected to various physical stem-end treatments as practised by florists. Their effects on longevity (vase life) and water relations [relative fresh weight (RFW) and vase solution uptake (VSU)] were quantified. All vase water contained sodium dichloroisocyanurate (DICA) biocide. Bark removal had either positive or neutral effects on the vase life of fresh-cut rose and had either neutral or negative effects on fresh-cut acacia. Stem-end splitting had either no or negative effects on the vase life of fresh-cut rose and acacia. However, both bark removal and stem-end splitting increased the vase life of both species when applied after short term storage for 24 h at 4 degrees C. Crushing stems had no effect on the vase life of fresh-cut rose, but tends to increase the vase life of fresh-cut acacia. Hot water scalding either increased or had no effect on the vase lives of rose and acacia. The tendency for bark removal to increase vase life of fresh-cut rose was associated with better maintenance of RFW and sustained VSU. However, for the most part, stem-end treatments had typically negative or neutral effects on RFW of fresh-cut rose and acacia. Likewise, the treatments had mostly negative or neutral effects on VSU. Overall for both species, there is little or no benefit and potentially negative effects on vase life, RFW and VSU of applying stem-end treatments as sometimes advocated by florists. (C) 2010 Elsevier B.V. All rights reserved

Inhibitors of oxidative enzymes affect water uptake and vaselife of cut Acacia holosericea and Chamelaucium uncinatum stems

Cut Acacia holosericea (Velvet Leaf Wattle) foliage has a short vase life, possibly because of blockage in xylem vessels. We indirectly investigated a hypothesised role for peroxidase and phenoloxidase enzyme activities in xylem occlusion of Acacia stems by using their inhibitors. We also tested these inhibitors with cut Chamelaucium uncinatum (Geraldton waxflower), another woody stemmed cut flower. The peroxidase inhibitors used were 3-amino-1,2,4-triazole (AT), catechol (CH), hydroquinone (HQ), p-phenylene diamine (PD) and copper sulphate (CS, Chamelaucium only). The catechol oxidase inhibitors were tropolone (TP), 4-hexylresorcinol (HR) and 2,3-dihydroxynaphthalene (DN). A laccase inhibitor, cetyltrimethylammonium bromide (CM), was also used. Other phenoloxidase inhibitors tested were p-chlorophenol (CP), p-nitrocathechol (NC), p-nitrophenol (NP) and sodium metabisulphite (SM). 2-Mercaptoethanol (ME), phenyl hydrazine (PH) and salicylhydroxamic acid (SH) were used as inhibitors of both peroxidase and phenoloxidase. Twelve inhibitors (CH, HQ, DN, HR, TP, CM, CP, NC, NP, SM, PH and SH) significantly improved water uptake, maintained relative fresh weight and increased vase life of Acacia at least once in two experiments. In Chamelaucium, six inhibitors had significant positive effects on water relations (CH, PD, CS, CM, CP and PH) and vase life (AT, CH, PD, CS, ME and PH), while four of them (DN, TP, NC and NP) were phytotoxic at applied concentrations. Only one of the 46 inhibitor treatments inhibited transpiration and increased fresh weight, suggesting that the inhibitors mainly acted by increasing water uptake. Overall, results indicate that oxidative enzyme activities, potentially through phenolic deposition, contribute to xylem occlusion in woody cut stems of Acacia and Chamelaucium

Responses of native Australian cut flowers to treatment with 1-methylcyclopropene and ethylene

Postharvest longevity of some cut flowers is shortened by exposure to ethylene gas. Adverse effects of ethylene may be prevented by treatment with 1-methylcyclopropene (1-MCP) gas. Responses of 14 different native Australian cut powers to 1-MCP and ethylene applied at concentrations of 10 nL.L-1 and 10 mu L.L-1, respectively, were examined. Each gas was applied alone for 12 hours at 20 degrees C and they were also applied in series. Vase lives of Ceratopetalum gummiferum, Chamelaucium uncinatum, Grevillea 'Kay Williams' and 'Misty Pink', Leptospermum petersonii, Telopea 'Shady Lady', and Verticordia nitens were reduced by ethylene treatment. Treatment with 1-MCP generally protected these cut flowers against subsequent exposure to ethylene. The 1-MCP treatment usually did not extend their vase lives in the absence of exogenous ethylene