104 research outputs found

    The first composite score predicting Digital Ulcers in systemic sclerosis patients using Clinical data, Imaging and Patient history-CIP-DUS

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    Background: Digital ulcers (DU) present a challenging complication in systemic sclerosis (SSc). The aim of this study was to combine clinical characteristics and imaging methods to a composite score for the prediction of DU in SSc patients. Methods: Seventy-nine SSc patients received clinical examination, their patient history was taken and nailfold capillaroscopy (NC), colour Doppler ultrasonography (CDUS) and fluorescence optical imaging (FOI) of the hands were performed at baseline. Newly developed DU over a period of approximately 12 months were registered. We used criteria with area under the curve (AUC) of at least 0.6 in regard to the development of these new DU to create the score (CIP-DUS, clinical features, imaging, patient history-digital ulcer score). Results: Twenty-nine percent of all SSc patients developed new DU during follow-up (48.1% diffuse, 18.4% limited SSc). Based on the cross-validated (cv) AUC, a weight (cvAUC > 0.6 and ≤ 0.65: 1; cvAUC > 0.65 and ≤ 0.7: 2; cvAUC > 0.7: 3) was assigned to each selected parameter. The performance of the final CIP-DUS was assessed with and without the CDUS/FOI component. For the scleroderma patterns in NC, three points were appointed to late, two to active and one point to early capillaroscopy pattern according to Cutolo et al. The CIP-DUS including the CDUS and FOI parameters resulted in a good diagnostic performance (AUC after cross-validation: 0.83, 95%CI 0.74 to 0.92) and was well calibrated (chi-square = 12.3, p = 0.58). The cut-off associated with the maximum of sensitivity and specificity was estimated at ≥ 10 points resulting in a sensitivity of 100% and specificity of 74% for new DU during follow-up. Excluding CDUS and FOI parameters leads to a non-statistically significant lower performance (AUC after cross-validation: 0.81, 95%CI 0.72 to 0.91). However, including CDUS and FOI resulted in a better classification of patients in respect to the outcome new DU in follow-up due to significantly better reclassification performance (NRI = 62.1, p = 0.001) and discrimination improvement (IDI = 9.7, p = 0.01). Conclusion: A new score was introduced with the aim to predict digital ulcers. If applied correctly and with the new imaging techniques proposed, all patients at risk of digital ulcers throughout 12 months could be identified

    Preliminary definitions for the sonographic features of synovitis in children

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    Objectives Musculoskeletal ultrasonography (US) has the potential to be an important tool in the assessment of disease activity in childhood arthritides. To assess pathology, clear definitions for synovitis need to be developed first. The aim of this study was to develop and validate these definitions through an international consensus process. Methods The decision on which US techniques to use, the components to be included in the definitions as well as the final wording were developed by 31 ultrasound experts in a consensus process. A Likert scale of 1-5 with 1 indicating complete disagreement and 5 complete agreement was used. A minimum of 80% of the experts scoring 4 or 5 was required for final approval. The definitions were then validated on 120 standardized US images of the wrist, MCP and tibiotalar joints displaying various degrees of synovitis at various ages. Results B-Mode and Doppler should be used for assessing synovitis in children. A US definition of the various components (i.e. synovial hypertrophy, effusion and Doppler signal within the synovium) was developed. The definition was validated on still images with a median of 89% (range 80-100) of participants scoring it as 4 or 5 on a Likert scale. Conclusions US definitions of synovitis and its elementary components covering the entire pediatric age range were successfully developed through a Delphi process and validated in a web-based still images exercise. These results provide the basis for the standardized US assessment of synovitis in clinical practice and research

    Monitoring of patients with rheumatoid arthritis by indocyanine green (ICG)-enhanced fluorescence optical imaging treated with anti-TNFα therapy

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    Background: Fluorescence optical imaging (FOI) enables visualisation of inflammation in both hands in rheumatoid arthritis (RA). Objective: To investigate the usefulness of FOI in treatment monitoring under anti-TNF alpha therapy with certolizumab pegol (CZP) in patients with RA in comparison to clinical and laboratory outcome parameters. Methods: CZP-naive patients with RA were eligible for this open-label study with an observational period of 52 weeks. Disease activity was monitored by the clinical score DAS28, tender/swollen joint count (TJC-28/SJC-28) and laboratory outcomes for systemic inflammation (CRP and ESR). FOI results were analysed in three different phases (P1-3) and PrimaVistaMode (PVM) by the FOI activity score (FOIAS). Results: Twenty-eight RA patients (median age 52.5 years, 26 females, thirteen with a history of other biologic therapy) were included. DAS28 (CRP) decreased from moderate disease activity at baseline (median 4.6, IQR 1.8) to low disease activity at week (w)52 (median 2.7, IQR 2.1; p < 0.001). Statistically significant decreases could also be demonstrated for SJC-28 and TJC-28. CRP/ESR were reduced numerically from baseline to w52. FOIAS in P1 (early phase) showed a continuous decrease of enhancement during the course of treatment period: from baseline (median 1.5, IQR 9.3) over w6 (median 1.0, IQR 3.0; p= 0.069), w12 (median 0.5, IQR 3.0; p = 0.171), w24 (n = 27 , median 0.0, IQR 3.0; p = 0.004), until w52 (n= 18, median 0.0, IQR 2.8; p = 0.091), which could not be presented for FOIAS in P2, P3 and PVM. Conclusion: FOI in P1 appears to be a valuable tool for fast and easy monitoring of treatment response to certolizumab in a clinical setting

    Helicity-Flip Off-Foward Parton Distributions of the Nucleon

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    We identify quark and gluon helicity-flip distributions defined between nucleon states of unequal momenta. The evolution of these distributions with change of renormalization scale is calculated in the leading-logarithmic approximation. The helicity-flip gluon distributions do not mix with any quark distribution and are thus a unique signature of gluons in the nucleon. Their contribution to the generalized virtual Compton process is obtained both in the form of a factorization theorem and an operator product expansion. In deeply virtual Compton scattering, they can be probed through distinct angular dependence of the cross section.Comment: a few corrections made, references change

    On Low-Energy Effective Actions in N = 2, 4 Superconformal Theories in Four Dimensions

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    We study some aspects of low-energy effective actions in 4-d superconformal gauge theories on the Coulomb branch. We describe superconformal invariants constructed in terms of N=2 abelian vector multiplet which play the role of building blocks for the N=2,4 supersymmetric low-energy effective actions. We compute the one-loop effective actions in constant N=2 field strength background in N=4 SYM theory and in N=2 SU(2) SYM theory with four hypermultiplets in fundamental representation. Using the classification of superconformal invariants we then find the manifestly N=2 superconformal form of these effective actions. While our explicit computations are done in the one-loop approximation, our conclusions about the structure of the effective actions in N=2 superconformal theories are general. We comment on some applications to supergravity - gauge theory duality in the description of D-brane interactions.Comment: 18 pages, latex, comments/reference adde

    The ρ\rho Meson Light-Cone Distribution Amplitudes of Leading Twist Revisited

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    We give a complete re-analysis of the leading twist quark-antiquark light-cone distribution amplitudes of longitudinal and transverse ρ\rho mesons. We derive Wandzura-Wilczek type relations between different distributions and update the coefficients in their conformal expansion using QCD sum rules including next-to-leading order radiative corrections. We find that the distribution amplitudes of quarks inside longitudinally and transversely polarized ρ\rho mesons have a similar shape, which is in contradiction to previous analyses.Comment: 21 pages, latex2e, requires a4wide.sty and epsf.sty, 6 PS figures include

    Scheme dependence of NLO corrections to exclusive processes

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    We apply the so-called conformal subtraction scheme to predict perturbatively exclusive processes beyond leading order. Taking into account evolution effects, we study the scheme dependence for the photon-to-pion transition form factor and the electromagnetic pion form factor at next-to-leading order for different pion distribution amplitudes. Relying on the conformally covariant operator product expansion and using the known higher order results for polarized deep inelastic scattering, we are able to predict perturbative corrections to the hard-scattering amplitude of the photon-to-pion transition form factor beyond next-to-leading order in the conformal scheme restricted to the conformal limit of the theory.Comment: RevTeX, 25 pages, 2 figures, 5 tables, minor changes, to be published in Phys. Rev.

    Superconformal operators in N=4 super-Yang-Mills theory

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    We construct, in the framework of the N=4 SYM theory, a supermultiplet of twist-two conformal operators and study their renormalization properties. The components of the supermultiplet have the same anomalous dimension and enter as building blocks into multi-particle quasipartonic operators. The latter are determined by the condition that their twist equals the number of elementary constituent fields from which they are built. A unique feature of the N=4 SYM is that all quasipartonic operators with different SU(4) quantum numbers fall into a single supermultiplet. Among them there is a subsector of the operators of maximal helicity, which has been known to be integrable in the multi-color limit in QCD, independent of the presence of supersymmetry. In the N=4 SYM theory, this symmetry is extended to the whole supermultiplet of quasipartonic operators and the one-loop dilatation operator coincides with a Hamiltonian of integrable SL(2|4) Heisenberg spin chain.Comment: 45 pages, Latex, 4 figure
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