1,218 research outputs found

    UV-mediated Regulation of the anti-senescence factor Tbx2

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    Several lines of evidence have implicated members of the developmentally important T-box gene family in cell cycle regulation and in cancer. Importantly, the highly related T-box factors Tbx2 and Tbx3 can suppress senescence through repressing the cyclin-dependent kinase inhibitors p19(ARF) and p21(WAF1/CIP1/SDII). Furthermore, Tbx2 is up-regulated in several cancers, including melanomas where it was shown to function as an anti-senescence factor, suggesting that this may be one of the mechanisms by which T-box proteins contribute to the oncogenic process. However, very little is known about whether Tbx2 is regulated by p21-mediated stress-induced senescence signaling pathways. In this study, using the MCF-7 breast cancer cell line known to overexpress Tbx2, we show that in response to stress induced by ultraviolet irradiation the Tbx2 protein is specifically phosphorylated by the p38 mitogen-activated protein kinase. Using site-directed mutagenesis and in vitro kinase assays, we have identified serine residues 336, 623, and 675 in the Tbx2 protein as the p38 target sites and show that these sites are phosphorylated in vivo. Importantly, we show by Western blotting, immunofluorescence, and reporter assays that this phosphorylation leads to increased Tbx2 protein levels, predominant nuclear localization of the protein, and an increase in the ability of Tbx2 to repress the p21(WAF1/CIP1/SDII) promoter. These results show for the first time that the ability of Tbx2 to repress the p21 gene is enhanced in response to a stress-induced senescence pathway, which leads to a better understanding of the regulation of the anti-senescence function of Tbx2

    Shared care in mental illness: A rapid review to inform implementation

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    <p>Abstract</p> <p>Background</p> <p>While integrated primary healthcare for the management of depression has been well researched, appropriate models of primary care for people with severe and persistent psychotic disorders are poorly understood. In 2010 the NSW (Australia) Health Department commissioned a review of the evidence on "shared care" models of ambulatory mental health services. This focussed on critical factors in the implementation of these models in clinical practice, with a view to providing policy direction. The review excluded evidence about dementia, substance use and personality disorders.</p> <p>Methods</p> <p>A rapid review involving a search for systematic reviews on The Cochrane Database of Systematic Reviews and Database of Abstracts of Reviews of Effects (DARE). This was followed by a search for papers published since these systematic reviews on Medline and supplemented by limited iterative searching from reference lists.</p> <p>Results</p> <p>Shared care trials report improved mental and physical health outcomes in some clinical settings with improved social function, self management skills, service acceptability and reduced hospitalisation. Other benefits include improved access to specialist care, better engagement with and acceptability of mental health services. Limited economic evaluation shows significant set up costs, reduced patient costs and service savings often realised by other providers. Nevertheless these findings are not evident across all clinical groups. Gains require substantial cross-organisational commitment, carefully designed and consistently delivered interventions, with attention to staff selection, training and supervision. Effective models incorporated linkages across various service levels, clinical monitoring within agreed treatment protocols, improved continuity and comprehensiveness of services.</p> <p>Conclusions</p> <p>"Shared Care" models of mental health service delivery require attention to multiple levels (from organisational to individual clinicians), and complex service re-design. Re-evaluation of the roles of specialist mental health staff is a critical requirement. As expected, no one model of "shared" care fits diverse clinical groups. On the basis of the available evidence, we recommended a local trial that examined the process of implementation of core principles of shared care within primary care and specialist mental health clinical services.</p

    Household ecology and out-migration among ethnic Karen along the Thai-Myanmar border

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    Local migration in developing-world settings, particularly among rural populations, is an important yet understudied demographic process. Research on migration in such populations can help us test and inform anthropological and demographic theory. Furthermore, it can lead to a better understanding of modern population distributions and epidemiologic landscapes

    Identification of novel small molecule inhibitors of adenovirus gene transfer using a high throughput screening approach

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    Due to many favourable attributes adenoviruses (Ads) are the most extensively used vectors for clinical gene therapy applications. However, following intravascular administration, the safety and efficacy of Ad vectors are hampered by the strong hepatic tropism and induction of a potent immune response. Such effects are determined by a range of complex interactions including those with neutralising antibodies, blood cells and factors, as well as binding to native cellular receptors (coxsackie adenovirus receptor (CAR), integrins). Once in the bloodstream, coagulation factor X (FX) has a pivotal role in determining Ad liver transduction and viral immune recognition. Due to difficulties in generating a vector devoid of multiple receptor binding motifs, we hypothesised that a small molecule inhibitor would be of value. Here, a pharmacological approach was implemented to block adenovirus transduction pathways. We developed a high throughput screening (HTS) platform to identify the small molecule inhibitors of FX-mediated Ad5 gene transfer. Using an in vitro fluorescence and cell-based HTS, we evaluated 10,240 small molecules. Following sequential rounds of screening, three compounds, T5424837, T5550585 and T5660138 were identified that ablated FX-mediated Ad5 transduction with low micromolar potency. The candidate molecules possessed common structural features and formed part of the one pharmacophore model. Focused, mini-libraries were generated with structurally related molecules and in vitro screening revealed novel hits with similar or improved efficacy. The compounds did not interfere with Ad5:FX engagement but acted at a subsequent step by blocking efficient intracellular transport of the virus. In vivo, T5660138 and its closely related analogue T5660136 significantly reduced Ad5 liver transgene expression at 48 h post-intravenous administration of a high viral dose (1 × 10&lt;sup&gt;11&lt;/sup&gt; vp/mouse). Therefore, this study identifies novel and potent small molecule inhibitors of the Ad5 transduction which may have applications in the Ad gene therapy setting

    Cumulative mutagenesis of the basic residues in the 201-218 region of insulin-like growth factor (IGF)-binding protein-5 results in progressive loss of both IGF-I binding and inhibition of IGF-I biological action

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    We have reported previously that mutation of two conserved nonbasic amino acids (G203 and Q209) within the highly basic 201–218 region in the C-terminal domain of IGF-binding protein-5 (IGFBP-5) decreases binding to IGFs. This study reveals that cumulative mutagenesis of the 10 basic residues in this region, to create the C-Term series of mutants, ultimately results in a 15-fold decrease in the affinity for IGF-I and a major loss in heparin binding. We examined the ability of mutants to inhibit IGF-mediated survival of MCF-7 cells and were able to demonstrate that this depended not only upon the affinity for IGF-I, but also the kinetics of this interaction, because IGFBP-5 mutants with similar affinity constants (KD) values, but with different association (Ka) and dissociation (Kd) rate values, had markedly different inhibitory properties. In contrast, the affinity for IGF-I provided no predictive value in terms of the ability of these mutants to enhance IGF action when bound to the substratum. Instead, these C-Term mutants appeared to enhance the actions of IGF-I by a combination of increased dissociation of IGF-IGFBP complexes from the substratum, together with dissociation of IGF-I from IGFBP-5 bound to the substratum. These effects of the IGFBPs were dependent upon binding to IGF-I, because a non-IGF binding mutant (N-Term) was unable to inhibit or enhance the actions of IGF-I. These results emphasize the importance of the kinetics of association/dissociation in determining the enhancing or inhibiting effects of IGFBP-5 and demonstrate the ability to generate an IGFBP-5 mutant with exclusively IGF-enhancing activity
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