426 research outputs found

    Osteochondral lesions in distal tarsal joints of Icelandic horses reveal strong associations between hyaline and calcified cartilage abnormalities

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    Osteochondral lesions in the joints of the distal tarsal region of young Icelandic horses provide a natural model for the early stages of osteoarthritis (OA) in low-motion joints. We describe and characterise mineralised and non-mineralised osteochondral lesions in left distal tarsal region joint specimens from twenty-two 30 ±1 month-old Icelandic horses. Combinations of confocal scanning light microscopy, backscattered electron scanning electron microscopy (including, importantly, iodine staining) and three-dimensional microcomputed tomography were used on specimens obtained with guidance from clinical imaging. Lesion-types were described and classified into groups according to morphological features. Their locations in the hyaline articular cartilage (HAC), articular calcified cartilage (ACC), subchondral bone (SCB) and the joint margin tissues were identified and their frequency in the joints recorded. Associations and correlations between lesion-types were investigated for centrodistal joints only. In centrodistal joints the lesion-types HAC chondrocyte loss, HAC fibrillation, HAC central chondrocyte clusters, ACC arrest and ACC advance had significant associations and strong correlations. These lesion-types had moderate to high frequency in centrodistal joints but low frequencies in tarsometatarsal and talocalcaneal-centroquartal joints. Joint margin lesion-types had no significant associations with other lesion-types in the centrodistal joints but high frequency in both the centrodistal and tarsometatarsal joints. The frequency of SCB lesion-types in all joints was low. Hypermineralised infill phase lesion-types were detected. Our results emphasise close associations between HAC and ACC lesions in equine centrodistal joints and the importance of ACC lesions in the development of OA in low-motion compression-loaded equine joints

    Osteochondrosis in the central and third tarsal bones of young horses

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    Recently, the central and third tarsal bones of 23 equine fetuses and foals were examined using micro-computed tomography. Radiological changes, including incomplete ossification and focal ossification defects interpreted as osteochondrosis, were detected in 16 of 23 cases. The geometry of the osteochondrosis defects suggested they were the result of vascular failure, but this requires histological confirmation. The study aim was to examine central and third tarsal bones from the 16 cases and to describe the tissues present, cartilage canals, and lesions, including suspected osteochondrosis lesions. Cases included 9 males and 7 females from 0 to 150 days of age, comprising 11 Icelandic horses, 2 standardbred horses, 2 warmblood riding horses, and 1 coldblooded trotting horse. Until 4 days of age, all aspects of the bones were covered by growth cartilage, but from 105 days, the dorsal and plantar aspects were covered by fibrous tissue undergoing intramembranous ossification. Cartilage canal vessels gradually decreased but were present in most cases up to 122 days and were absent in the next available case at 150 days. Radiological osteochondrosis defects were confirmed in histological sections from 3 cases and consisted of necrotic vessels surrounded by ischemic chondronecrosis (articular osteochondrosis) and areas of retained, morphologically viable hypertrophic chondrocytes (physeal osteochondrosis). The central and third tarsal bones formed by both endochondral and intramembranous ossification. The blood supply to the growth cartilage of the central and third tarsal bones regressed between 122 and 150 days of age. Radiological osteochondrosis defects represented vascular failure, with chondrocyte necrosis and retention, or a combination of articular and physeal osteochondrosis

    Interleukin-1 polymorphisms associated with increased risk of gastric cancer

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    Helicobacter pylori infection is associated with a variety of clinical outcomes including gastric cancer and duodenal ulcer disease. The reasons for this variation are not clear, but the gastric physiological response is influenced by the severity and anatomical distribution of gastritis induced by H. pylori. Thus, individuals with gastritis predominantly localized to the antrum retain normal (or even high) acid secretion, whereas individuals with extensive corpus gastritis develop hypochlorhydria and gastric atrophy, which are presumptive precursors of gastric cancer. Here we report that interleukin-1 gene cluster polymorphisms suspected of enhancing production of interleukin-1-beta are associated with an increased risk of both hypochlorhydria induced by H. pylori and gastric cancer. Two of these polymorphism are in near-complete linkage disequilibrium and one is a TATA-box polymorphism that markedly affects DNA-protein interactions in vitro. The association with disease may be explained by the biological properties of interleukin-1-beta, which is an important pro-inflammatory cytokine and a powerful inhibitor of gastric acid secretion. Host genetic factors that affect interleukin-1-beta may determine why some individuals infected with H. pylori develop gastric cancer while others do no

    The mechanisms and processes of connection: developing a causal chain model capturing impacts of receiving recorded mental health recovery narratives.

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    BACKGROUND: Mental health recovery narratives are a core component of recovery-oriented interventions such as peer support and anti-stigma campaigns. A substantial number of recorded recovery narratives are now publicly available online in different modalities and in published books. Whilst the benefits of telling one's story have been investigated, much less is known about how recorded narratives of differing modalities impact on recipients. A previous qualitative study identified connection to the narrator and/or to events in the narrative to be a core mechanism of change. The factors that influence how individuals connect with a recorded narrative are unknown. The aim of the current study was to characterise the immediate effects of receiving recovery narratives presented in a range of modalities (text, video and audio), by establishing the mechanisms of connection and the processes by which connection leads to outcomes. METHOD: A study involving 40 mental health service users in England was conducted. Participants were presented with up to 10 randomly-selected recovery narratives and were interviewed on the immediate impact of each narrative. Thematic analysis was used to identify the mechanisms of connection and how connection leads to outcome. RESULTS: Receiving a recovery narrative led participants to reflect upon their own experiences or those of others, which then led to connection through three mechanisms: comparing oneself with the narrative and narrator; learning about other's experiences; and experiencing empathy. These mechanisms led to outcomes through three processes: the identification of change (through attending to narrative structure); the interpretation of change (through attending to narrative content); and the internalisation of interpretations. CONCLUSIONS: This is the first study to identify mechanisms and processes of connection with recorded recovery narratives. The empirically-based causal chain model developed in this study describes the immediate effects on recipients. This model can inform selection of narratives for use in interventions, and be used to support peer support workers in recounting their own recovery narratives in ways which are maximally beneficial to others

    The Heavy Photon Search test detector

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    The Heavy Photon Search (HPS), an experiment to search for a hidden sector photon in fixed target electroproduction, is preparing for installation at the Thomas Jefferson National Accelerator Facility (JLab) in the Fall of 2014. As the first stage of this project, the HPS Test Run apparatus was constructed and operated in 2012 to demonstrate the experiment׳s technical feasibility and to confirm that the trigger rates and occupancies are as expected. This paper describes the HPS Test Run apparatus and readout electronics and its performance. In this setting, a heavy photon can be identified as a narrow peak in the e+e− invariant mass spectrum above the trident background or as a narrow invariant mass peak with a decay vertex displaced from the production target, so charged particle tracking and vertexing are needed for its detection. In the HPS Test Run, charged particles are measured with a compact forward silicon microstrip tracker inside a dipole magnet. Electromagnetic showers are detected in a PbW04 crystal calorimeter situated behind the magnet, and are used to trigger the experiment and identify electrons and positrons. Both detectors are placed close to the beam line and split top-bottom. This arrangement provides sensitivity to low-mass heavy photons, allows clear passage of the unscattered beam, and avoids the spray of degraded electrons coming from the target. The discrimination between prompt and displaced e+e− pairs requires the first layer of silicon sensors be placed only 10 cm downstream of the target. The expected signal is small, and the trident background huge, so the experiment requires very large statistics. Accordingly, the HPS Test Run utilizes high-rate readout and data acquisition electronics and a fast trigger to exploit the essentially 100% duty cycle of the CEBAF accelerator at JLab

    Integration and continuity of primary care: polyclinics and alternatives - a patient-centred analysis of how organisation constrains care co-ordination

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    Background An ageing population, the increasing specialisation of clinical services and diverse health-care provider ownership make the co-ordination and continuity of complex care increasingly problematic. The way in which the provision of complex health care is co-ordinated produces – or fails to produce – six forms of continuity of care (cross-sectional, longitudinal, flexible, access, informational and relational). Care co-ordination is accomplished by a combination of activities by patients themselves; provider organisations; care networks co-ordinating the separate provider organisations; and overall health-system governance. This research examines how far organisational integration might promote care co-ordination at the clinical level. Objectives To examine (1) what differences the organisational integration of primary care makes, compared with network governance, to horizontal and vertical co-ordination of care; (2) what difference provider ownership (corporate, partnership, public) makes; (3) how much scope either structure allows for managerial discretion and ‘performance’; (4) differences between networked and hierarchical governance regarding the continuity and integration of primary care; and (5) the implications of the above for managerial practice in primary care. Methods Multiple-methods design combining (1) the assembly of an analytic framework by non-systematic review; (2) a framework analysis of patients’ experiences of the continuities of care; (3) a systematic comparison of organisational case studies made in the same study sites; (4) a cross-country comparison of care co-ordination mechanisms found in our NHS study sites with those in publicly owned and managed Swedish polyclinics; and (5) the analysis and synthesis of data using an ‘inside-out’ analytic strategy. Study sites included professional partnership, corporate and publicly owned and managed primary care providers, and different configurations of organisational integration or separation of community health services, mental health services, social services and acute inpatient care. Results Starting from data about patients’ experiences of the co-ordination or under-co-ordination of care, we identified five care co-ordination mechanisms present in both the integrated organisations and the care networks; four main obstacles to care co-ordination within the integrated organisations, of which two were also present in the care networks; seven main obstacles to care co-ordination that were specific to the care networks; and nine care co-ordination mechanisms present in the integrated organisations. Taking everything into consideration, integrated organisations appeared more favourable to producing continuities of care than did care networks. Network structures demonstrated more flexibility in adding services for small care groups temporarily, but the expansion of integrated organisations had advantages when adding new services on a longer term and a larger scale. Ownership differences affected the range of services to which patients had direct access; primary care doctors’ managerial responsibilities (relevant to care co-ordination because of their impact on general practitioner workload); and the scope for doctors to develop special interests. We found little difference between integrated organisations and care networks in terms of managerial discretion and performance. Conclusions On balance, an integrated organisation seems more likely to favour the development of care co-ordination and, therefore, continuities of care than a system of care networks. At least four different variants of ownership and management of organisationally integrated primary care providers are practicable in NHS-like settings. Future research is therefore required, above all to evaluate comparatively the different techniques for coordinating patient discharge across the triple interface between hospitals, general practices and community health services; and to discover what effects increasing the scale and scope of general practice activities will have on continuity of care

    Plasma neurofilament light in behavioural variant frontotemporal dementia compared to mood and psychotic disorders

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    OBJECTIVE: Blood biomarkers of neuronal injury such as neurofilament light (NfL) show promise to improve diagnosis of neurodegenerative disorders and distinguish neurodegenerative from primary psychiatric disorders (PPD). This study investigated the diagnostic utility of plasma NfL to differentiate behavioural variant frontotemporal dementia (bvFTD, a neurodegenerative disorder commonly misdiagnosed initially as PPD), from PPD, and performance of large normative/reference data sets and models. METHODS: Plasma NfL was analysed in major depressive disorder (MDD, n = 42), bipolar affective disorder (BPAD, n = 121), treatment-resistant schizophrenia (TRS, n = 82), bvFTD (n = 22), and compared to the reference cohort (Control Group 2, n = 1926, using GAMLSS modelling), and age-matched controls (Control Group 1, n = 96, using general linear models). RESULTS: Large differences were seen between bvFTD (mean NfL 34.9 pg/mL) and all PPDs and controls (all < 11 pg/mL). NfL distinguished bvFTD from PPD with high accuracy, sensitivity (86%), and specificity (88%). GAMLSS models using reference Control Group 2 facilitated precision interpretation of individual levels, while performing equally to or outperforming models using local controls. Slightly higher NfL levels were found in BPAD, compared to controls and TRS. CONCLUSIONS: This study adds further evidence on the diagnostic utility of NfL to distinguish bvFTD from PPD of high clinical relevance to a bvFTD differential diagnosis, and includes the largest cohort of BPAD to date. Using large reference cohorts, GAMLSS modelling and the interactive Internet-based application we developed, may have important implications for future research and clinical translation. Studies are underway investigating utility of plasma NfL in diverse neurodegenerative and primary psychiatric conditions in real-world clinical settings

    Measurement of the B0_s semileptonic branching ratio to an orbitally excited D_s** state, Br(B0_s -> Ds1(2536) mu nu)

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    In a data sample of approximately 1.3 fb-1 collected with the D0 detector between 2002 and 2006, the orbitally excited charm state D_s1(2536) has been observed with a measured mass of 2535.7 +/- 0.6 (stat) +/- 0.5 (syst) MeV via the decay mode B0_s -> D_s1(2536) mu nu X. A first measurement is made of the branching ratio product Br(b(bar) -> D_s1(2536) mu nu X).Br(D_s1(2536)->D* K0_S). Assuming that D_s1(2536) production in semileptonic decay is entirely from B0_s, an extraction of the semileptonic branching ratio Br(B0_s -> D_s1(2536) mu nu X) is made.Comment: 7 pages, 2 figures, LaTeX, version with minor changes as accepted by Phys. Rev. Let

    Simultaneous measurement of the ratio B(t->Wb)/B(t->Wq) and the top quark pair production cross section with the D0 detector at sqrt(s)=1.96 TeV

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    We present the first simultaneous measurement of the ratio of branching fractions, R=B(t->Wb)/B(t->Wq), with q being a d, s, or b quark, and the top quark pair production cross section sigma_ttbar in the lepton plus jets channel using 0.9 fb-1 of ppbar collision data at sqrt(s)=1.96 TeV collected with the D0 detector. We extract R and sigma_ttbar by analyzing samples of events with 0, 1 and >= 2 identified b jets. We measure R = 0.97 +0.09-0.08 (stat+syst) and sigma_ttbar = 8.18 +0.90-0.84 (stat+syst)} +/-0.50 (lumi) pb, in agreement with the standard model prediction.Comment: submitted to Phys.Rev.Letter

    Search for W' bosons decaying to an electron and a neutrino with the D0 detector

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    This Letter describes the search for a new heavy charged gauge boson W' decaying into an electron and a neutrino. The data were collected with the D0 detector at the Fermilab Tevatron proton-antiproton Collider at a center-of-mass energy of 1.96 TeV, and correspond to an integrated luminosity of about 1 inverse femtobarn. Lacking any significant excess in the data in comparison with known processes, an upper limit is set on the production cross section times branching fraction, and a W' boson with mass below 1.00 TeV can be excluded at the 95% C.L., assuming standard-model-like couplings to fermions. This result significantly improves upon previous limits, and is the most stringent to date.Comment: submitted to Phys. Rev. Let
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