1,291 research outputs found

    Detecting Fauna Habitat in Semi-Arid Grasslands Using Satellite Imagery

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    Managing grasslands for biodiversity conservation is a relatively recent phenomenon and there is uncertainty over the most effective strategy. Past research has found that intermediate levels of disturbance (e.g. burning or grazing) may be required to maintain the natural mosaic of small-scale patterning required for a diverse range of flora and fauna species. For sustainable grassland management, appropriate methods of spatial assessment and temporal monitoring are required, to facilitate understanding of how past and present climate, land management and landscape features influence vegetation structure. Due to the expense and time-consuming nature of conventional ground-based monitoring, satellite remote-sensing techniques offer a feasible approach

    Activation of transforming growth factor-β(1 )and early atherosclerosis in systemic lupus erythematosus

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    The efficiency of activating latent transforming growth factor (TGF)-β(1 )in systemic lupus erythematosus (SLE) may control the balance between inflammation and fibrosis, modulating the disease phenotype. To test this hypothesis we studied the ability to activate TGF-β(1 )in SLE patients and control individuals within the context of inflammatory disease activity, cumulative organ damage and early atherosclerosis. An Activation Index (AI) for TGF-β(1 )was determined for 32 patients with SLE and 33 age-matched and sex-matched control individuals by quantifying the increase in active TGF-β(1 )under controlled standard conditions. Apoptosis in peripheral blood mononuclear cells was determined by fluorescence-activated cell sorting. Carotid artery intima-media thickness was measured using standard Doppler ultrasound. These measures were compared between patients and control individuals. In an analysis conducted in patients, we assessed the associations of these measures with SLE phenotype, including early atherosclerosis. Both intima-media thickness and TGF-β(1 )AI for SLE patients were within the normal range. There was a significant inverse association between TGF-β(1 )AI and levels of apoptosis in peripheral blood mononuclear cells after 24 hours in culture for both SLE patients and control individuals. Only in SLE patients was there a significant negative correlation between TGF-β(1 )AI and low-density lipoprotein cholesterol (r = -0.404; P = 0.022) and between TGF-β(1 )AI and carotid artery intima-media thickness (r = -0.587; P = 0.0004). A low AI was associated with irreversible damage (SLICC [Systemic Lupus International Collaborating Clinics] Damage Index ≥1) and was inversely correlated with disease duration. Intima-media thickness was significantly linked to total cholesterol (r = 0.371; P = 0.037). To conclude, in SLE low normal TGF-β(1 )activation was linked with increased lymphocyte apoptosis, irreversible organ damage, disease duration, calculated low-density lipoprotein levels and increased carotid IMT, and may contribute to the development of early atherosclerosis

    The BILAG2004-Pregnancy Index is a valid disease activity outcome measure for pregnant SLE patients

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    OBJECTIVES: This study was to determine whether the BILAG2004-Pregnancy Index (BILAG2004-P) has construct/criterion validity and is sensitive to change. METHODS: This was an observational multicentre study that recruited pregnant SLE patients. Data were collected on disease activity [using the BILAG2004-P and Physician Global Assessment (PGA)], investigations and therapy at each assessment. The overall BILAG2004-P score as determined by the highest score achieved by any system was used in the analysis. Cross-sectional analysis was used for construct and criterion validity. The comparison was with C3, C4 and anti-dsDNA for construct validity, while it was with change in therapy and PGA in criterion validity. Sensitivity to change was assessed by determining the relationship between the change in BILAG2004-P and the change in therapy between two consecutive visits. RESULTS: A total of 97 patients with 112 pregnancies were recruited. There were 610 assessments available for construct/criterion validity analysis (98.2% of pregnancies had more than one assessment) and 497 observations for sensitivity to change analysis. Increasing BILAG2004-P scores were associated with low C3. The active BILAG2004-P score (grade A or B) was associated with an increase in therapy and the PGA of active disease. There was an increasing likelihood of higher overall scores with an increase in therapy and the PGA of active disease. In the sensitivity to change analysis, an increase in the BILAG2004-P score was associated with an increase in therapy and inversely associated with a decrease in therapy. A decrease in the BILAG2004-P score was associated with a decrease in therapy and inversely associated with an increase in therapy. CONCLUSION: The BILAG2004-P has criterion validity and is sensitive to change

    An investigation of dendritic delay in octopus cells of the mammalian cochlear nucleus

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    Octopus cells, located in the mammalian auditory brainstem, receive their excitatory synaptic input exclusively from auditory nerve fibers (ANFs). They respond with accurately timed spikes but are broadly tuned for sound frequency. Since the representation of information in the auditory nerve is well understood, it is possible to pose a number of questions about the relationship between the intrinsic electrophysiology, dendritic morphology, synaptic connectivity, and the ultimate functional role of octopus cells in the brainstem. This study employed a multi-compartmental Hodgkin-Huxley model to determine whether dendritic delay in octopus cells improves synaptic input coincidence detection in octopus cells by compensating for the cochlear traveling wave delay. The propagation time of post-synaptic potentials from synapse to soma was investigated. We found that the total dendritic delay was approximately 0.275 ms. It was observed that low-threshold potassium channels in the dendrites reduce the amplitude dependence of the dendritic delay of post-synaptic potentials. As our hypothesis predicted, the model was most sensitive to acoustic onset events, such as the glottal pulses in speech when the synaptic inputs were arranged such that the model's dendritic delay compensated for the cochlear traveling wave delay across the ANFs. The range of sound frequency input from ANFs was also investigated. The results suggested that input to octopus cells is dominated by high frequency ANFs

    The challenges in data integration – heterogeneity and complexity in clinical trials and patient registries of Systemic Lupus Erythematosus

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    From Springer Nature via Jisc Publications RouterHistory: received 2019-09-23, accepted 2020-06-19, registration 2020-06-19, pub-electronic 2020-06-24, online 2020-06-24, collection 2020-12Publication status: PublishedFunder: Medical Research Council; doi: http://dx.doi.org/10.13039/501100000265; Grant(s): MR/M01665X/1, MR/N00583X/1Abstract: Background: Individual clinical trials and cohort studies are a useful source of data, often under-utilised once a study has ended. Pooling data from multiple sources could increase sample sizes and allow for further investigation of treatment effects; even if the original trial did not meet its primary goals. Through the MASTERPLANS (MAximizing Sle ThERapeutic PotentiaL by Application of Novel and Stratified approaches) national consortium, focused on Systemic Lupus Erythematosus (SLE), we have gained valuable real-world experiences in aligning, harmonising and combining data from multiple studies and trials, specifically where standards for data capture, representation and documentation, were not used or were unavailable. This was not without challenges arising both from the inherent complexity of the disease and from differences in the way data were captured and represented across different studies. Main body: Data were, unavoidably, aligned by hand, matching up equivalent or similar patient variables across the different studies. Heterogeneity-related issues were tackled and data were cleaned, organised and combined, resulting in a single large dataset ready for analysis. Overcoming these hurdles, often seen in large-scale data harmonization and integration endeavours of legacy datasets, was made possible within a realistic timescale and limited resource by focusing on specific research questions driven by the aims of MASTERPLANS. Here we describe our experiences tackling the complexities in the integration of large, diverse datasets, and the lessons learned. Conclusions: Harmonising data across studies can be complex, and time and resource consuming. The work carried out here highlights the importance of using standards for data capture, recording, and representation, to facilitate both the integration of large datasets and comparison between studies. Where standards are not implemented at the source harmonisation is still possible by taking a flexible approach, with systematic preparation, and a focus on specific research questions

    Endothelial progenitor cells: a new player in lupus?

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    Patients with systemic lupus erythematosus (SLE) have a greatly increased risk of cardiovascular disease. There is growing interest in the link between vascular damage and lupus-specific inflammatory factors. Impaired endothelial repair could account for the endothelial dysfunction in this patient group. This review describes the contribution that endothelial progenitor cells could play in the pathogenesis of premature vascular damage in this disease. The methods of isolation, detection, and characterization of endothelial progenitor cells, together with their potential role in repair of the endothelium and as a therapeutic target in SLE, are discussed
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