977 research outputs found
Organometallic Compounds of the Lanthanides, 41 [1]. The Crystal and Molecular Structure of (C5Me5)2HoCl(THF)
The title compound (1) is obtained as brownish crystals by reaction of HOCl3 with NaC5Me5 in tetrahydrofuran. The structure of 1, which has two slightly different independent molecules per asymmetric unit, has been elucidated by X-ray analysis. The crystals are triclinic with a = 1686.2(8) pm, b = 1816(1) pm, c = 846.5(4) pm, α = 92.02(7)°, β = 92.47(9)°, γ = 63.21(5)°, space group P1̄, D(calcd) = 1.560 g/cm3, and R = 0.0286, for 6219 observed reflections with I > 3σ(I)
Symptom complexes in patients with seropositive arthralgia and in patients newly diagnosed with rheumatoid arthritis: a qualitative exploration of symptom development
Objective: The aim of this study was to explore symptoms and symptom development during the earliest phases of rheumatoid arthritis (RA) in patients with seropositive arthralgia and patients newly diagnosed with RA
Field Dependence of the Josephson Plasma Resonance in Layered Superconductors with Alternating Junctions
The Josephson plasma resonance in layered superconductors with alternating
critical current densities is investigated in a low perpendicular magnetic
field. In the vortex solid phase the current densities and the squared bare
plasma frequencies decrease linearly with the magnetic field. Taking into
account the coupling due to charge fluctuations on the layers, we extract from
recent optical data for SmLa_{1-x} Sr_x CuO_{4-delta} the Josephson penetration
length lambda_{ab} approximately 1100 A parallel to the layers at T=10 K.Comment: 5 pages, 6 eps-figures, final version with minor misprints correcte
Does the presence of magnetic resonance imaging-detected osteitis at diagnosis with rheumatoid arthritis lower the risk for achieving disease-modifying antirheumatic drug-free sustained remission: Results of a longitudinal study
Background: Although infrequent, some rheumatoid arthritis (RA) patients achieve disease-modifying antirheumatic drug (DMARD)-free sustained remission. The absence of RA-specific autoantibodies, such as anticitrullinated protein antibodies (ACPA), is known to be associated with this outcome but further mechanisms underlying the chronic nature of RA are largely unknown. Magnetic resonance imaging (MRI)-detected bone marrow edema (BME), or osteitis, strongly predicts erosive progression and is associated with ACPA positivity. Therefore, we hypothesized that the presence of MRI-detected osteitis is also predictive of not achieving DMARD-free sustained remission and that the presence of osteitis mediates the association between ACPA and DMARD-free sustained remission. Methods: A 1.5 T unilateral hand and foot MRI was performed at disease presentation in 238 RA patients, evaluating BME, synovitis, and tenosynovitis (summed as MRI inflammation score). DMARD-free sustained remission, defined as the absence of clinical synovitis after DMARD cessation that persisted during the total follow-up, was assessed (median follow-up 3.8 years). Associations between the different MRI-detected inflammatory features and this outcome were studied. A mediation analysis was performed to study whether the presence of BME mediated the association between ACPA and DMARD-free sustained remission. Finally, patterns of MRI-detected inflammation with regard to DMARD-free sustained remission were studied using partial least squares (PLS) regression. Results: Forty-six (19.3%) patients achieved DMARD-free sustained remission. ACPA positivity associated independently with remission (hazard ratio (HR) 0.16, 95% confidence interval (CI) 0.06-0.39). In contrast, no associations were observed between MRI-detected BME (HR 0.99, 95% CI 0.94-1.03), or other MRI inflammatory features, and achieving DMARD-free sustained remission. Thus, the presence of BME did not mediate the association between ACPA and DMARD-free sustained rem
Peer interactions in residential youth care:A validation study of the Peer Interactions in Residential Youth Care (PIRY) Questionnaire
Interactions among peers in residential youth care are an important dynamic factor affecting behavioral adjustment and treatment success. Assessment and monitoring of the quality of peer interactions are potentially important for promoting a positive peer culture at the living group, contributing to a positive social climate. However, currently, there are no measures available to assess peer interactions in residential youth care. The present study describes the development, construct validity, and reliability of the Peer Interactions in Residential Youth Care questionnaire (PIRY) in a sample of 345 adolescents (age M = 15.45, SD = 1.59, 44.9% male) in the Netherlands. Confirmatory factor analysis of a two-factor model (peer support and acceptance, and relational aggression) showed a good fit to the data, and internal consistency reliabilities were good for both scales. Partial strict measurement invariance for gender was established, and no significant differences were found between boys and girls on latent factor means. The PIRY can be used in practice to assess and monitor both positive and negative peer interactions in residential youth care at the group level. Implications for research and practice are discussed
Contribution of tenosynovitis of small joints to the symptom morning stiffness in patients presenting with undifferentiated and rheumatoid arthritis
Objective: Morning stiffness (MS) is characteristic of rheumatoid arthritis (RA). Despite its association with functional disability, the extent to which local inflammatory processes contribute to this symptom is unknown. Magnetic resonance imaging (MRI)-detected tenosynovitis of small joints is recognized as an early feature of RA, which is also associated with functional impairments. It has been proposed that tenosynovitis contributes to MS. Therefore, we assessed the relationship between MS and MRI-detected inflammation, in particular tenosynovitis. Method: In total, 286 consecutive patients newly presenting with undifferentiated arthritis and RA underwent contrast-enhanced 1.5 T MRI of (2–5) metacarpophalangeal, wrist, and (1–5) metatarsophalangeal joints. Scans were scored for tenosynovitis according to Haavardsholm, and for synovitis by Rheumatoid Arthritis Magnetic Resonance Imaging Scoring (RAMRIS). MS was dichotomized as ≥ 60 min or not. Associations between MS and tenosynovitis/synovitis were tested with logistic regression, data were categorized (solitary or simultaneous presence of synovitis/tenosynovitis), and the presence of an additive interaction was assessed. Results: MS was present in 40% of patients. Tenosynovitis was more often present in patients with MS than without MS [80% vs 65%, odds ratio (OR) 2.11, 95% confidence interval (1.21;3.69)]. Synovitis was more often present in patients with MS [58% vs 44%, OR 1.79 (1.11;2.91)]. In categorized analyses, concurrent synovitis and tenosynovitis had the largest association [OR 2.43 (1.30;4.54)], in contrast to solitary synovitis [OR 0.85 (0.21;3.47)]. The additive interaction was non-significant. The variance explained in all analyses was small (range 4–5%). Conclusion: Tenosynovitis, combined with synovitis, at small joints is associated with MS and contributes to the pathophysiology of MS
The relationship between the presence of anti-cyclic citrullinated peptide antibodies and clinical phenotype in very early rheumatoid arthritis
<p>Abstract</p> <p>Background</p> <p>Anti-cyclic citrullinated peptide (anti-CCP) antibodies are highly specific for RA, but are not detectable in all RA patients. The aim of this study was to establish whether the clinical phenotypes of anti-CCP positive and negative disease are distinct at the earliest clinically apparent phase of disease.</p> <p>Methods</p> <p>Patients were recruited from the Birmingham early inflammatory arthritis clinic. Participants were included in the current study if they presented within 3 months of symptom onset and fulfilled 1987 ACR criteria for RA at some point during an 18 month follow-up. Data were collected on demographic variables, joint symptoms and tender (n = 68) and swollen (n = 66) joint counts. CRP, ESR, rheumatoid factor and anti-CCP2 status were measured.</p> <p>Results</p> <p>92 patients were included (48 anti-CCP positive). The anti-CCP positive and negative groups were comparable in terms of demographic variables, inflammatory markers, joint counts and 1987 ACR classification criteria, except that more anti-CCP positive patients were rheumatoid factor positive (83.3% vs. 11.4%, p < 0.01). There was no significant difference in the pattern of joint involvement, except for an increased prevalence of knee joint swelling in anti-CCP positive patients (42.9% vs. 22.2%, p = 0.03).</p> <p>Conclusions</p> <p>Patients with and without anti-CCP antibodies present in a similar way, even within three months of clinically apparent disease that eventually develops into RA.</p
Reliability of Magnetic Resonance Imaging (MRI) scoring of the metatarsophalangeal joints of the foot according to the Rheumatoid Arthritis MRI Score
Objective. The Rheumatoid Arthritis Magnetic Resonance Imaging Score (RAMRIS) is validated for hand MRI. Its reliability applied to metatarsophalangeal (MTP 1-5) joints is unknown and was studied in early arthritis and clinically suspect arthralgia.Methods. Patients underwent 1.5 Tesla MRI of MTP, metacarpophalangeal (MCP 2-5), and wrist joints. Two paired readers scored bone marrow edema (BME), synovitis, tenosynovitis, and erosions. Interreader reliability was assessed of 441 consecutive early arthritis patients at baseline, 215 by 2 readers, and the remaining 226 by 2 different readers. Two readers scored baseline MRI of 82 consecutive patients with clinically suspect arthralgia, and 40 randomly selected patients by 9 readers. Intrareader reliability was determined on a random set of 15 early arthritis patients, scored twice by 2 readers. For change scores, 30 early arthritis patients with baseline and 1-year followup MRI were scored by 2 readers. Intraclass correlation coefficients (ICC), Bland-Altman (BA) plots, and smallest detectable change (SDC) were determined. MRI data of MTP joints were compared to wrist and MCP joints.Results. Interreader ICC and mean scores in early arthritis were BME ICC 0.91-0.92 (mean 1.5 +/- SD 2.6), synovitis 0.90-0.92 (1.3 +/- 1.7), tenosynovitis 0.80-0.85 (1.1 +/- 1.8), and erosions 0.88-0.89 (0.7 +/- 1.0). In patients with clinically suspect arthralgia, ICC were comparable. Intrareader ICC for inflammatory MRI features were 0.84-0.98, for erosions 0.71 (reader 1), and 0.92 (reader 2). Change score ICC were = 0.90, except erosions (0.77). SDC were = 1.0. BA plots showed no systematic bias. Reliability scores of MTP joints were similar to MCP and wrist joints.Conclusion. Status and change MRI scores of BME, synovitis, tenosynovitis, and erosions of MTP joints can be assessed reliably by RAMRIS.Imaging- and therapeutic targets in neoplastic and musculoskeletal inflammatory diseas
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Treatment and reconstruction of large bone defects, delayed unions, and nonunions is challenging and has resulted in an ongoing search for novel tissue-engineered therapies. Bone morphogenetic protein-2 (BMP-2) gene therapy is a promising strategy to provide sustained production of BMP-2 locally. Alginate polymer-based nonviral gene therapy with BMP-2 plasmid DNA (pBMP-2) in constructs with multipotent mesenchymal stromal cells (MSCs) has resulted in prolonged gene expression and bone formation in vivo. To further translate this technology toward larger animal models, important issues remain to be investigated, such as the necessity of seeded cells as a target for gene therapy. For that purpose, a large animal-screening model in an orthotopic location, with fully separated chambers, was investigated. Four cylinder-shaped implants were placed in the iliac crests of ten goats. Polycaprolactone tubes around each implant allowed bone ingrowth from the underlying bone and bone marrow and ensured separation of the experimental conditions. An empty tube showed low levels of spontaneous bone ingrowth, and implantation of autologous bone indicated proper bone function with respect to remodeling and resorption. Control ceramic scaffolds were compared to scaffolds containing pBMP-2 either or not combined with seeded MSCs. Fluorochrome incorporation evaluated at 3, 6, and 9 weeks and histomorphometry at 12 weeks after implantation revealed clear differences between the groups, with pBMP-2 combined with MSCs being the most effective. The BMP-2 was demonstrated in a variety of bone-residing cells through immunohistochemistry. Further analysis indicated that multinucleated giant cells might have an important role in transgene expression. Taken together, this work introduces a large animal model for studying bone formation at multiple sites simultaneously in an orthotopic location. The model appeared robust, showed no neighboring effects, and demonstrated effectivity of combined cell and gene therapy
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