1,829 research outputs found

    The O-glycomap of lubricin, a novel mucin responsible for joint lubrication, identified by site-specific glycopeptide analysis

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    The lubricative, heavily glycosylated mucin-like synovial glycoprotein lubricin has previously been observed to contain glycosylation changes related to rheumatoid and osteoarthritis. Thus, a site-specific investigation of the glycosylation of lubricin was undertaken, in order to further understand the pathological mechanisms involved in these diseases. Lubricin contains an serine/threonine/proline (STP)-rich domain composed of imperfect tandem repeats (EPAPTTPK), the target for O-glycosylation. In this study, using a liquid chromatography–tandem mass spectrometry approach, employing both collision-induced and electron-transfer dissociation fragmentation methods, we identified 185 O-glycopeptides within the STP-rich domain of human synovial lubricin. This showed that adjacent threonine residues within the central STP-rich region could be simultaneously and/or individually glycosylated. In addition to core 1 structures responsible for biolubrication, core 2 O-glycopeptides were also identified, indicating that lubricin glycosylation may have other roles. Investigation of the expression of polypeptide N-acetylgalactosaminyltransferase genes was carried out using cultured primary fibroblast-like synoviocytes, a cell type that expresses lubricin in vivo. This analysis showed high mRNA expression levels of the less understood polypeptide N-acetylgalactosaminyltransferase 15 and 5 in addition to the ubiquitously expressed polypeptide N-acetylgalactosaminyltransferase 1 and 2 genes. This suggests that there is a unique combination of transferase genes important for the O-glycosylation of lubricin. The site-specific glycopeptide analysis covered 82% of the protein sequence and showed that lubricin glycosylation displays both micro- and macroheterogeneity. The density of glycosylation was shown to be high: 168 sites of O-glycosylation, predominately sialylated, were identified. These glycosylation sites were focused in the central STP-rich region, giving the domain a negative charge. The more positively charged lysine and arginine residues in the N and C termini suggest that synovial lubricin exists as an amphoteric molecule. The identification of these unique properties of lubricin may provide insight into the important low-friction lubricating functions of lubricin during natural joint movement

    Pre-Prandial Vinegar Ingestion Improves Two-Hour Glucose Control in Older, Type II Diabetics More Than Post-Prandial Walking

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    Background: Exercise engagement benefits diabetic patients through an insulin-like effect on muscle. Literature indicates that vinegar consumption may lower blood glucose levels. It is not currently clarified whether a relative amount of vinegar ingestion or a walking bout is more effective at controlling glucose in older, Type II diabetics during the acute phase following a meal. Purpose: The aim was to directly compare the impact of preferred-pace walking (15 min, postprandial) versus ingestion of a relative quantity of vinegar (0.3 g/kg) on two-hour glucose control. Methods: The two arms of the trial were completed in a randomized, crossover manner. Six Type II diabetic patients (Females = 5; Males = 1; Age = 70.5 ± 9.0 yrs.) enrolled and underwent baseline finger pricks to establish glucose levels. The test meal consisted of an 85 g bagel, 13 g of butter, and 237 mL of orange juice. On the respective days, the vinegar was diluted into 59 mL of orange juice and ingested before the meal or the subject completed a 15-min walk at 15 min post-meal. For both trials, glucose was checked every 30 min following the test meal. Results: One subject was removed from all present analysis due to medication-related non-compliance. For the vinegar trial, the resting heart rate was 72.0 (± 9.5) and baseline, 30-, 60-, 90-, and 120-min average blood glucose levels were: 117 (±12), 149 (±39), 172 (±49), 185 (±49), and 180 (±44) mg/dl. For the preferred walking speed phase, the resting heart rate was 75.5 (±15.6) and baseline, 30-, 60-, 90-, and 120-min average glucose levels were: 113 (±10), 147 (±53), 180 (±53), 208 (±72), and 206 (±71) mg/dl. Preferred walking speed was found to average 3.1 (± 1.5) kph and total steps averaged 1418 (±376). The between-arm comparison of glucose at 120-min trended towards significance (p = 0.081). Conclusions: Compared with a bout of walking, a relative quantity of vinegar may serve as a more suitable mechanism for older Type II diabetics to control acute spikes in glucose after a high carbohydrate meal. With an adequately-powered analysis, between-arm comparisons at multiple time-points would likely have achieved statistical significance. Nevertheless, the meaningfulness of the glucose control exhibited should not be lost due to the lack of statistical significance. Finally, the slow absolute preferred walking pace of many older adults may undermine the ability for walking to result in sufficient energy expenditure capable of subsequent glucose control

    Decrease of core 2 O-glycans on synovial lubricin in osteoarthritis reduces galectin-3 mediated crosslinking

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    The synovial fluid glycoprotein lubricin (also known as proteoglycan 4) is a mucin-type O-linked glycosylated biological lubricant implicated to be involved in osteoarthritis (OA) development. Lubricin\u27s ability to reduce friction is related to its glycosylation consisting of sialylated and unsialylated Tn-antigens and core 1 and core 2 structures. The glycans on lubricin have also been suggested to be involved in crosslinking and stabilization of the lubricating superficial layer of cartilage by mediating interaction between lubricin and galectin-3. However, with the spectrum of glycans being found on lubricin, the glycan candidates involved in this interaction were unknown. Here, we confirm that the core 2 O-linked glycans mediate this lubricin-galectin-3 interaction, shown by surface plasmon resonance data indicating that recombinant lubricin (rhPRG4) devoid of core 2 structures did not bind to recombinant galectin-3. Conversely, transfection of Chinese hamster ovary cells with the core 2 GlcNAc transferase acting on a mucin-type O-glycoprotein displayed increased galectin-3 binding. Both the level of galectin-3 and the galectin-3 interactions with synovial lubricin were found to be decreased in late-stage OA patients, coinciding with an increase in unsialylated core 1 O-glycans (T-antigens) and Tn-antigens. These data suggest a defect in crosslinking of surface-active molecules in OA and provide novel insights into OA molecular pathology

    Measurement of the prompt J/psi and psi(2S) polarizations in pp collisions at sqrt(s) = 7 TeV

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    The polarizations of prompt J/psi and psi(2S) mesons are measured in proton-proton collisions at sqrt(s) = 7 TeV, using a dimuon data sample collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of 4.9 inverse femtobarns. The prompt J/psi and psi(2S) polarization parameters lambda[theta], lambda[phi], and lambda[theta, phi], as well as the frame-invariant quantity lambda(tilde), are measured from the dimuon decay angular distributions in three different polarization frames. The J/psi results are obtained in the transverse momentum range 14 < pt < 70 GeV, in the rapidity intervals abs(y) < 0.6 and 0.6 < abs(y) < 1.2. The corresponding psi(2S) results cover 14 < pt < 50 GeV and include a third rapidity bin, 1.2 < abs(y) < 1.5. No evidence of large transverse or longitudinal polarizations is seen in these kinematic regions, which extend much beyond those previously explored

    The CMS Phase-1 pixel detector upgrade

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    The CMS detector at the CERN LHC features a silicon pixel detector as its innermost subdetector. The original CMS pixel detector has been replaced with an upgraded pixel system (CMS Phase-1 pixel detector) in the extended year-end technical stop of the LHC in 2016/2017. The upgraded CMS pixel detector is designed to cope with the higher instantaneous luminosities that have been achieved by the LHC after the upgrades to the accelerator during the first long shutdown in 2013–2014. Compared to the original pixel detector, the upgraded detector has a better tracking performance and lower mass with four barrel layers and three endcap disks on each side to provide hit coverage up to an absolute value of pseudorapidity of 2.5. This paper describes the design and construction of the CMS Phase-1 pixel detector as well as its performance from commissioning to early operation in collision data-taking.Peer reviewe

    Alignment of the CMS tracker with LHC and cosmic ray data

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    © CERN 2014 for the benefit of the CMS collaboration, published under the terms of the Creative Commons Attribution 3.0 License by IOP Publishing Ltd and Sissa Medialab srl. Any further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation and DOI.The central component of the CMS detector is the largest silicon tracker ever built. The precise alignment of this complex device is a formidable challenge, and only achievable with a significant extension of the technologies routinely used for tracking detectors in the past. This article describes the full-scale alignment procedure as it is used during LHC operations. Among the specific features of the method are the simultaneous determination of up to 200 000 alignment parameters with tracks, the measurement of individual sensor curvature parameters, the control of systematic misalignment effects, and the implementation of the whole procedure in a multi-processor environment for high execution speed. Overall, the achieved statistical accuracy on the module alignment is found to be significantly better than 10μm

    Improving sexual health through partner notification : the LUSTRUM mixed-methods research Programme including RCT of accelerated partner therapy

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    Background Sexually transmitted infections disproportionately affect young people and men who have sex with men. Chlamydia is Britain’s most common sexually transmitted infection. Partner notification is a key intervention to reduce transmission of sexually transmitted infections and human immunodeficiency virus but is hard to implement. Accelerated partner therapy is a promising new approach. Objectives determine the effectiveness, costs and acceptability of accelerated partner therapy for chlamydia in heterosexual people model the cost effectiveness of accelerated partner therapy and impact on chlamydia transmission develop and cost partner notification interventions for men who have sex with men. Design Mixed-methods study to develop a new sex partner classification and optimise accelerated partner therapy; cluster crossover randomised controlled trial of accelerated partner therapy, with process and cost-consequence evaluation; dynamic modelling and health economic evaluation; systematic review of economic studies of partner notification for sexually transmitted infections in men who have sex with men; qualitative research to co-design a novel partner notification intervention for men who have sex with men with bacterial sexually transmitted infections. Settings Sexual health clinics and community services in England and Scotland. Participants Women and men, including men who have sex with men and people with mild learning disabilities. Interventions Accelerated partner therapy offered as an additional partner notification method. Main outcome measures Proportion of index patients with positive repeat chlamydia test (primary outcome); proportion of sex partners treated; costs per major outcome averted and quality-adjusted life-year; predicted chlamydia prevalence; experiences of accelerated partner therapy. Data sources Randomised controlled trial: partnership type, resource use, outcomes, qualitative data: economic analysis, modelling and systematic review: resource use and unit costs from the randomised controlled trial, secondary sources. Results The sex partner classification defined five types. Accelerated partner therapy modifications included simplified self-sampling packs and creation of training films. We created a clinical management and partner notification data collection system. In the randomised controlled trial, all 17 enrolled clinics completed both periods; 1536 patients were enrolled in the intervention phase and 1724 were enrolled in the control phase. Six hundred and sixty-six (43%) of 1536 index patients in the intervention phase and 800 (46%) of 1724 in the control phase were tested for Chlamydia trachomatis at 12–24 weeks after contact tracing consultation; 31 (4.7%) in the intervention phase and 53 (6.6%) in the control phase had a positive Chlamydia trachomatis test result [adjusted odds ratio 0.66 (95% confidence interval 0.41 to 1.04); p = 0.071]. The proportion of index patients with ≥ 1 sex partner treated was 88.0% (775/881) in intervention and 84.6% (760/898) in control phase, adjusted odds ratio 1.27 (95% confidence interval 0.96 to 1.68; p = 0.10). Overall, 293/1536 (19.1%) index patients chose accelerated partner therapy for 305 partners, of which partner types were: committed/established, 166/305 (54.4%); new, 85/305 (27.9%); occasional, 45/305 (14.8%); and one-off, 9/305 (3.0%). Two hundred and forty-eight accepted accelerated partner therapy and 241 partners were sent accelerated partner therapy packs, 120/241 (49.8%) returned chlamydia/gonorrhoea samples (78/119, 65.5%, positive for chlamydia, no result in one), but only 60/241 (24.9%) human immunodeficiency virus and syphilis samples (all negative). The primary outcomes of the randomised trial were not statistically significantly different at the 5% level. However, the economic evaluation found that accelerated partner therapy could be less costly compared with routine care, and mathematical modelling of effects and costs extrapolated beyond the trial end points suggested that accelerated partner therapy could be more effective and less costly than routine care in terms of major outcome averted and quality-adjusted life-years’. Healthcare professionals did not always offer accelerated partner therapy but felt that a clinical management and partner notification data collection system enhanced data recording. Key elements of a multilevel intervention supporting men who have sex with men in partner notification included: modifying the cultural and social context of men who have sex with men communities; improving skills and changing services to facilitate partner notification for one-off partners; and working with dating app providers to explore digital partner notification options. The systematic review found no evaluations of partner notification for men who have sex with men. Modelling of gonorrhoea and human immunodeficiency virus co-infection in men who have sex with men was technically challenging. Limitations In the randomised controlled trial, enrolment, follow-up and repeat infections were lower than expected, so statistical power was lower than anticipated. We were unable to determine whether accelerated partner therapy sped up partner treatment. Mathematical modelling of gonorrhoea/human immunodeficiency virus co-infection in men who have sex with men remained at an experimental stage. It was not feasible to include healthcare professionals in the men who have sex with men intervention development due to the COVID-19 pandemic. Conclusions Although the evidence that the intervention reduces repeat infection was not conclusive, the trial results suggest that accelerated partner therapy can be safely offered as a contact tracing option and is also likely to be cost saving, but is best suited to sex partners with emotional connection to the index patient. The Programme’s findings about classification of sexual partner types can be implemented in sexual health care with auditable outcomes. Future work Further research is needed on how to increase uptake of accelerated partner therapy and increase sexually transmitted infections self-sampling by partners; understand how services can use partnership-type information to improve partner notification, especially for those currently underserved; overcome challenges in modelling sexually transmitted infections and human immunodeficiency virus co-infection in men who have sex with men; develop and evaluate an intervention to optimise partner notification among men who have sex with men, focusing on one-off partnerships. Trial registration This trial is registered as ISRCTN15996256. Funding This award was funded by the National Institute for Health and Care Research (NIHR) Programme Grants for Applied Research Programme (NIHR award ref: RP-PG-0614-20009) and is published in full in Programme Grants for Applied Research; Vol. 12, No. 2. See the NIHR Funding and Awards website for further award information
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