458 research outputs found

    Synthesis of new chiral organosulfur donors with hydrogen bonding functionality and their first charge transfer salts

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    The syntheses of a range of enantiopure organosulfur donors with hydrogen bonding groups are described including TTF related materials with two, four, six and eight hydroxyl groups and multiple stereogenic centres and a pair of chiral N-substituted BEDT-TTF acetamides. Three charge transfer salts of enantiopure poly-hydroxy-substituted donors are reported, including a 4:1 salt with the meso stereoisomer of the dinuclear [Fe2(oxalate)5 ]4- anion in which both cation and anion have chiral components linked together by hydrogen bonding, and a semiconducting salt with triiodide

    Human neutrophil clearance of bacterial pathogens triggers anti-microbial gamma delta T cell responses in early infection

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    Human blood Vc9/Vd2 T cells, monocytes and neutrophils share a responsiveness toward inflammatory chemokines and are rapidly recruited to sites of infection. Studying their interaction in vitro and relating these findings to in vivo observations in patients may therefore provide crucial insight into inflammatory events. Our present data demonstrate that Vc9/Vd2 T cells provide potent survival signals resulting in neutrophil activation and the release of the neutrophil chemoattractant CXCL8 (IL-8). In turn, Vc9/Vd2 T cells readily respond to neutrophils harboring phagocytosed bacteria, as evidenced by expression of CD69, interferon (IFN)-c and tumor necrosis factor (TNF)-a. This response is dependent on the ability of these bacteria to produce the microbial metabolite (E)-4-hydroxy-3-methyl-but-2-enyl pyrophosphate (HMB-PP), requires cell-cell contact of Vc9/Vd2 T cells with accessory monocytes through lymphocyte function-associated antigen-1 (LFA-1), and results in a TNF-a dependent proliferation of Vc9/Vd2 T cells. The antibiotic fosmidomycin, which targets the HMB-PP biosynthesis pathway, not only has a direct antibacterial effect on most HMB-PP producing bacteria but also possesses rapid anti-inflammatory properties by inhibiting cd T cell responses in vitro. Patients with acute peritoneal-dialysis (PD)-associated bacterial peritonitis – characterized by an excessive influx of neutrophils and monocytes into the peritoneal cavity – show a selective activation of local Vc9/Vd2 T cells by HMB-PP producing but not by HMB-PP deficient bacterial pathogens. The cd T celldriven perpetuation of inflammatory responses during acute peritonitis is associated with elevated peritoneal levels of cd T cells and TNF-a and detrimental clinical outcomes in infections caused by HMB-PP positive microorganisms. Taken together, our findings indicate a direct link between invading pathogens, neutrophils, monocytes and microbe-responsive cd T cells in early infection and suggest novel diagnostic and therapeutic approaches.Martin S. Davey, Chan-Yu Lin, Gareth W. Roberts, Sinéad Heuston, Amanda C. Brown, James A. Chess, Mark A. Toleman, Cormac G.M. Gahan, Colin Hill, Tanya Parish, John D. Williams, Simon J. Davies, David W. Johnson, Nicholas Topley, Bernhard Moser and Matthias Eber

    The potential psychological benefits of Active Video Games in the rehabilitation of musculoskeletal injuries and deficiencies: A narrative review of the literature

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    Background: Recent literature suggests that Active Video Games (AVGs) may offer potential psychological benefits during the rehabilitation of musculoskeletal injuries and their corresponding deficiencies. Objectives: To review existing literature regarding the potential psychological benefits of AVGs within the context of rehabilitation from musculoskeletal injury or debilitation. Method: A narrative review of the literature that used the Population, Intervention, Comparison, and Outcomes PICO method was conducted. The literature review included studies that discussed and/or investigated potential psychological benefits of AVGs during musculoskeletal rehabilitation. Of the total 163 papers that were identified, 30 met the inclusion criteria. Results: The Nintendo® WiiTM (Nintendo Co., Ltd, Kyoto, Japan) was the most commonly-used games console that was employed in AVG interventions (15 out of 21), and these studies that investigated potential psychological benefits were typically conducted with elderly populations. These studies reported that using AVGs in musculoskeletal rehabilitation resulted in a number of positive psychological effects (e.g., enjoyment, effects on self). However, most studies lacked a clear theoretical framework, and varied greatly in their designs and methodologies. Conclusion: Despite encouraging findings of AVG use, insufficient evidence exists to reliably verify or refute the potential psychological benefits of AVGs in musculoskeletal rehabilitation. It is recommended that future studies in this area contain a theoretical framework to ensure greater consistency in the methodology used and the execution of the intervention. The potential findings of such investigations may result in the development of optimal, client-tailored rehabilitation programmes

    A role for subchondral bone changes in the process of osteoarthritis; a micro-CT study of two canine models

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    BACKGROUND: This study evaluates changes in peri-articular bone in two canine models for osteoarthritis: the groove model and the anterior cruciate ligament transection (ACLT) model. METHODS: Evaluation was performed at 10 and 20 weeks post-surgery and in addition a 3-weeks time point was studied for the groove model. Cartilage was analysed, and architecture of the subchondral plate and trabecular bone of epiphyses was quantified using micro-CT. RESULTS: At 10 and 20 weeks cartilage histology and biochemistry demonstrated characteristic features of osteoarthritis in both models (very mild changes at 3 weeks). The groove model presented osteophytes only at 20 weeks, whereas the ACLT model showed osteophytes already at 10 weeks. Trabecular bone changes in the groove model were small and not consistent. This contrasts the ACLT model in which bone volume fraction was clearly reduced at 10 and 20 weeks (15-20%). However, changes in metaphyseal bone indicate unloading in the ACLT model, not in the groove model. For both models the subchondral plate thickness was strongly reduced (25-40%) and plate porosity was strongly increased (25-85%) at all time points studied. CONCLUSION: These findings show differential regulation of subchondral trabecular bone in the groove and ACLT model, with mild changes in the groove model and more severe changes in the ACLT model. In the ACLT model, part of these changes may be explained by unloading of the treated leg. In contrast, subchondral plate thinning and increased porosity were very consistent in both models, independent of loading conditions, indicating that this thinning is an early response in the osteoarthritis process

    Laboratory Evolution of Fast-Folding Green Fluorescent Protein Using Secretory Pathway Quality Control

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    Green fluorescent protein (GFP) has undergone a long history of optimization to become one of the most popular proteins in all of cell biology. It is thermally and chemically robust and produces a pronounced fluorescent phenotype when expressed in cells of all types. Recently, a superfolder GFP was engineered with increased resistance to denaturation and improved folding kinetics. Here we report that unlike other well-folded variants of GFP (e.g., GFPmut2), superfolder GFP was spared from elimination when targeted for secretion via the SecYEG translocase. This prompted us to hypothesize that the folding quality control inherent to this secretory pathway could be used as a platform for engineering similar ‘superfolded’ proteins. To test this, we targeted a combinatorial library of GFPmut2 variants to the SecYEG translocase and isolated several superfolded variants that accumulated in the cytoplasm due to their enhanced folding properties. Each of these GFP variants exhibited much faster folding kinetics than the parental GFPmut2 protein and one of these, designated superfast GFP, folded at a rate that even exceeded superfolder GFP. Remarkably, these GFP variants exhibited little to no loss in specific fluorescence activity relative to GFPmut2, suggesting that the process of superfolding can be accomplished without altering the proteins' normal function. Overall, we demonstrate that laboratory evolution combined with secretory pathway quality control enables sampling of largely unexplored amino-acid sequences for the discovery of artificial, high-performance proteins with properties that are unparalleled in their naturally occurring analogues

    The provocative lumbar facet joint

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    Low back pain is the most common pain symptom experienced by American adults and is the second most common reason for primary care physician visits. There are many structures in the lumbar spine that can serve as pain generators and often the etiology of low back pain is multifactorial. However, the facet joint has been increasingly recognized as an important cause of low back pain. Facet joint pain can be diagnosed with local anesthetic blocks of the medial branches or of the facet joints themselves. Subsequent radiofrequency lesioning of the medial branches can provide more long-term pain relief. Despite some of the pitfalls associated with facet joint blocks, they have been shown to be valid, safe, and reliable as a diagnostic tool. Medial branch denervation has shown some promise for the sustained control of lumbar facet joint-mediated pain, but at this time, there is insufficient evidence that it is a wholly efficacious treatment option. Developing a universal algorithm for evaluating facet joint-mediated pain and standard procedural techniques may facilitate the performance of larger outcome studies. This review article provides an overview of the anatomy, pathophysiology, diagnosis, and treatment of facet joint-mediated pain

    Genetic risk and a primary role for cell-mediated immune mechanisms in multiple sclerosis.

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    Multiple sclerosis is a common disease of the central nervous system in which the interplay between inflammatory and neurodegenerative processes typically results in intermittent neurological disturbance followed by progressive accumulation of disability. Epidemiological studies have shown that genetic factors are primarily responsible for the substantially increased frequency of the disease seen in the relatives of affected individuals, and systematic attempts to identify linkage in multiplex families have confirmed that variation within the major histocompatibility complex (MHC) exerts the greatest individual effect on risk. Modestly powered genome-wide association studies (GWAS) have enabled more than 20 additional risk loci to be identified and have shown that multiple variants exerting modest individual effects have a key role in disease susceptibility. Most of the genetic architecture underlying susceptibility to the disease remains to be defined and is anticipated to require the analysis of sample sizes that are beyond the numbers currently available to individual research groups. In a collaborative GWAS involving 9,772 cases of European descent collected by 23 research groups working in 15 different countries, we have replicated almost all of the previously suggested associations and identified at least a further 29 novel susceptibility loci. Within the MHC we have refined the identity of the HLA-DRB1 risk alleles and confirmed that variation in the HLA-A gene underlies the independent protective effect attributable to the class I region. Immunologically relevant genes are significantly overrepresented among those mapping close to the identified loci and particularly implicate T-helper-cell differentiation in the pathogenesis of multiple sclerosis

    Site-specific analysis of gene expression in early osteoarthritis using the Pond-Nuki model in dogs

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    BACKGROUND: Osteoarthritis (OA) is a progressive and debilitating disease that often develops from a focal lesion and may take years to clinically manifest to a complete loss of joint structure and function. Currently, there is not a cure for OA, but early diagnosis and initiation of treatment may dramatically improve the prognosis and quality of life for affected individuals. This study was designed to determine the feasibility of analyzing changes in gene expression of articular cartilage using the Pond-Nuki model two weeks after ACL-transection in dogs, and to characterize the changes observed at this time point. METHODS: The ACL of four dogs was completely transected arthroscopically, and the contralateral limb was used as the non-operated control. After two weeks the dogs were euthanatized and tissues harvested from the tibial plateau and femoral condyles of both limbs. Two dogs were used for histologic analysis and Mankin scoring. From the other two dogs the surface of the femoral condyle and tibial plateau were divided into four regions each, and tissues were harvested from each region for biochemical (GAG and HP) and gene expression analysis. Significant changes in gene expression were determined using REST-XL, and Mann-Whitney rank sum test was used to analyze biochemical data. Significance was set at (p < 0.05). RESULTS: Significant differences were not observed between ACL-X and control limbs for Mankin scores or GAG and HP tissue content. Further, damage to the tissue was not observed grossly by India ink staining. However, significant changes in gene expression were observed between ACL-X and control tissues from each region analyzed, and indicate that a unique regional gene expression profile for impending ACL-X induced joint pathology may be identified in future studies. CONCLUSION: The data obtained from this study lend credence to the research approach and model for the characterization of OA, and the identification and validation of future diagnostic modalities. Further, the changes observed in this study may reflect the earliest changes in AC reported during the development of OA, and may signify pathologic changes within a stage of disease that is potentially reversible

    Relationship between radiographic changes and symptoms or physical examination findings in subjects with symptomatic medial knee osteoarthritis: a three-year prospective study

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    <p>Abstract</p> <p>Background</p> <p>Although osteoarthritis (OA) of the knee joints is the most common and debilitating joint disease in developed countries, the factors that determine the severity of symptoms are not yet understood well. Subjects with symptomatic medial knee OA were followed up prospectively to explore the relationship between radiographic changes and symptoms or physical examination findings.</p> <p>Methods</p> <p>One-hundred six OA knees in 68 subjects (mean age 71.1 years; 85% women) were followed up at 6-month intervals over 36 months. At each visit, knee radiographs were obtained, symptoms were assessed by a validated questionnaire, and the result of physical examination was recorded systematically using a specific chart. Correlations between the change of radiographs and clinical data were investigated in a longitudinal manner.</p> <p>Results</p> <p>During the study period, the narrowing of joint space width (JSW) was observed in 34 joints (32%). Although those knees were clinically or radiographically indistinguishable at baseline from those without JSW narrowing, differences became apparent at later visits during the follow-up. The subjects with knees that underwent JSW narrowing had severer symptoms, and the symptoms tended to be worse for those with higher rates of narrowing. A significant correlation was not found between the severity of symptoms and the growth of osteophytes. For the knees that did not undergo radiographic progression, the range of motion improved during the follow-up period, possibly due to the reduction of knee pain. Such improvement was not observed with the knees that underwent JSW narrowing or osteophyte growth.</p> <p>Conclusion</p> <p>The result of this study indicates that the symptoms of knee OA patients tend to be worse when JSW narrowing is underway. This finding may explain, at least partly, a known dissociation between the radiographic stage of OA and the severity of symptoms.</p
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