46 research outputs found
International mixed methods study protocol to develop a patient-reported outcome measure for all types of chronic wounds (the WOUND-Q)
INTRODUCTION: Most patient-reported outcome measures (PROM) for chronic wounds are specific to a single wound type (eg, pressure ulcer) or part of the body. A barrier to outcome assessment in wound care and research is the lack of a rigorously designed PROM that can be used across wound types and locations. This mixed method study describes the protocol for an international collaboration to develop and validate a new PROM called the WOUND-Q for adults with chronic wounds. METHODS AND ANALYSIS: In phase I, the qualitative approach of interpretive description is used to elicit concepts important to people with wounds regarding outcome. Participants from Canada, Denmark, the Netherlands, and the USA are aged 18 years and older and have a wound that has lasted 3 months or longer. Interviews are digitally recorded, transcribed and coded. A conceptual framework and preliminary item pool are developed from the qualitative dataset. Draft scales are formed to cover important themes in the conceptual framework. These scales are refined using feedback from people with chronic wounds and wound care experts. After refinement, the scales are translated into Danish and Dutch, following rigorous methods, to prepare for an international field-test study. In phase II, data are collected in Canada, Denmark, the Netherlands, and the USA. An international sample of people with a large variety of chronic wounds complete the WOUND-Q. Rasch Measurement Theory analysis is used to identify the best subset of items to retain for each scale and to
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Population stratification may bias analysis of PGC-1α as a modifier of age at Huntington disease motor onset
Huntington’s disease (HD) is an inherited neurodegenerative disorder characterized by motor, cognitive and behavioral disturbances, caused by the expansion of a CAG trinucleotide repeat in the HD gene. The CAG allele size is the major determinant of age at onset (AO) of motor symptoms, although the remaining variance in AO is highly heritable. The rs7665116 SNP in PPARGC1A, encoding the mitochondrial regulator PGC-1α, has been reported to be a significant modifier of AO in three European HD cohorts, perhaps due to affected cases from Italy. We attempted to replicate these findings in a large collection of (1,727) HD patient DNA samples of European origin. In the entire cohort, rs7665116 showed a significant effect in the dominant model (p value = 0.008) and the additive model (p value = 0.009). However, when examined by origin, cases of Southern European origin had an increased rs7665116 minor allele frequency (MAF), consistent with this being an ancestry-tagging SNP. The Southern European cases, despite similar mean CAG allele size, had a significantly older mean AO (p < 0.001), suggesting population-dependent phenotype stratification. When the generalized estimating equations models were adjusted for ancestry, the effect of the rs7665116 genotype on AO decreased dramatically. Our results do not support rs7665116 as a modifier of AO of motor symptoms, as we found evidence for a dramatic effect of phenotypic (AO) and genotypic (MAF) stratification among European cohorts that was not considered in previously reported association studies. A significantly older AO in Southern Europe may reflect population differences in genetic or environmental factors that warrant further investigation
Mutant Huntingtin induces activation of the Bcl-2/adenovirus E1B 19-kDa interacting protein (BNip3)
Huntington's disease (HD) is a neurodegenerative disorder characterized by progressive neuronal death in the basal ganglia and cortex. Although increasing evidence supports a pivotal role of mitochondrial dysfunction in the death of patients' neurons, the molecular bases for mitochondrial impairment have not been elucidated. We provide the first evidence of an abnormal activation of the Bcl-2/adenovirus E1B 19-kDa interacting protein 3 (BNip3) in cells expressing mutant Huntingtin. In this study, we show an abnormal accumulation and dimerization of BNip3 in the mitochondria extracted from human HD muscle cells, HD model cell cultures and brain tissues from HD model mice. Importantly, we have shown that blocking BNip3 expression and dimerization restores normal mitochondrial potential in human HD muscle cells. Our data shed light on the molecular mechanisms underlying mitochondrial dysfunction in HD and point to BNip3 as a new potential target for neuroprotective therapy in HD
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Candidate glutamatergic and dopaminergic pathway gene variants do not influence Huntington’s disease motor onset
Huntington’s disease (HD) is a neurodegenerative disorder characterized by motor, cognitive, and behavioral disturbances. It is caused by the expansion of the HTT CAG repeat, which is the major determinant of age at onset (AO) of motor symptoms. Aberrant function of N-methyl-D-aspartate receptors and/or overexposure to dopamine has been suggested to cause significant neurotoxicity, contributing to HD pathogenesis. We used genetic association analysis in 1,628 HD patients to evaluate candidate polymorphisms in N-methyl-D-aspartate receptor subtype genes (GRIN2A rs4998386 and rs2650427, and GRIN2B rs1806201) and functional polymorphisms in genes in the dopamine pathway (DAT1 3′ UTR 40-bp variable number tandem repeat (VNTR), DRD4 exon 3 48-bp VNTR, DRD2 rs1800497, and COMT rs4608) as potential modifiers of the disease process. None of the seven polymorphisms tested was found to be associated with significant modification of motor AO, either in a dominant or additive model, after adjusting for ancestry. The results of this candidate-genetic study therefore do not provide strong evidence to support a modulatory role for these variations within glutamatergic and dopaminergic genes in the AO of HD motor manifestations
Electronic anisotropy, magnetic field-temperature phase diagram and their dependence on resistivity in c-axis oriented MgB2 thin films
An important predicted, but so far uncharacterized, property of the new
superconductor MgB2 is electronic anisotropy arising from its layered crystal
structure. Here we report on three c-axis oriented thin films, showing that the
upper critical field anisotropy ratio Hc2par/Hc2perp is 1.8 to 2.0, the ratio
increasing with higher resistivity. Measurements of the magnetic
field-temperature phase diagram show that flux pinning disappears at H* ~
0.8Hc2perp(T) in untextured samples. Hc2par(0) is strongly enhanced by alloying
to 39 T for the highest resistivity film, more than twice that seen in bulk
samples.Comment: 5 pages Acrobat 3.02 pd
Correlation of Inter-Locus Polyglutamine Toxicity with CAG•CTG Triplet Repeat Expandability and Flanking Genomic DNA GC Content
Dynamic expansions of toxic polyglutamine (polyQ)-encoding CAG repeats in ubiquitously expressed, but otherwise unrelated, genes cause a number of late-onset progressive neurodegenerative disorders, including Huntington disease and the spinocerebellar ataxias. As polyQ toxicity in these disorders increases with repeat length, the intergenerational expansion of unstable CAG repeats leads to anticipation, an earlier age-at-onset in successive generations. Crucially, disease associated alleles are also somatically unstable and continue to expand throughout the lifetime of the individual. Interestingly, the inherited polyQ length mediating a specific age-at-onset of symptoms varies markedly between disorders. It is widely assumed that these inter-locus differences in polyQ toxicity are mediated by protein context effects. Previously, we demonstrated that the tendency of expanded CAG•CTG repeats to undergo further intergenerational expansion (their ‘expandability’) also differs between disorders and these effects are strongly correlated with the GC content of the genomic flanking DNA. Here we show that the inter-locus toxicity of the expanded polyQ tracts of these disorders also correlates with both the expandability of the underlying CAG repeat and the GC content of the genomic DNA flanking sequences. Inter-locus polyQ toxicity does not correlate with properties of the mRNA or protein sequences, with polyQ location within the gene or protein, or steady state transcript levels in the brain. These data suggest that the observed inter-locus differences in polyQ toxicity are not mediated solely by protein context effects, but that genomic context is also important, an effect that may be mediated by modifying the rate at which somatic expansion of the DNA delivers proteins to their cytotoxic state
Candidate glutamatergic and dopaminergic pathway gene variants do not influence Huntington’s disease motor onset
Identification of genetic variants associated with Huntington's disease progression: a genome-wide association study
Background Huntington's disease is caused by a CAG repeat expansion in the huntingtin gene, HTT. Age at onset has been used as a quantitative phenotype in genetic analysis looking for Huntington's disease modifiers, but is hard to define and not always available. Therefore, we aimed to generate a novel measure of disease progression and to identify genetic markers associated with this progression measure. Methods We generated a progression score on the basis of principal component analysis of prospectively acquired longitudinal changes in motor, cognitive, and imaging measures in the 218 indivduals in the TRACK-HD cohort of Huntington's disease gene mutation carriers (data collected 2008–11). We generated a parallel progression score using data from 1773 previously genotyped participants from the European Huntington's Disease Network REGISTRY study of Huntington's disease mutation carriers (data collected 2003–13). We did a genome-wide association analyses in terms of progression for 216 TRACK-HD participants and 1773 REGISTRY participants, then a meta-analysis of these results was undertaken. Findings Longitudinal motor, cognitive, and imaging scores were correlated with each other in TRACK-HD participants, justifying use of a single, cross-domain measure of disease progression in both studies. The TRACK-HD and REGISTRY progression measures were correlated with each other (r=0·674), and with age at onset (TRACK-HD, r=0·315; REGISTRY, r=0·234). The meta-analysis of progression in TRACK-HD and REGISTRY gave a genome-wide significant signal (p=1·12 × 10−10) on chromosome 5 spanning three genes: MSH3, DHFR, and MTRNR2L2. The genes in this locus were associated with progression in TRACK-HD (MSH3 p=2·94 × 10−8 DHFR p=8·37 × 10−7 MTRNR2L2 p=2·15 × 10−9) and to a lesser extent in REGISTRY (MSH3 p=9·36 × 10−4 DHFR p=8·45 × 10−4 MTRNR2L2 p=1·20 × 10−3). The lead single nucleotide polymorphism (SNP) in TRACK-HD (rs557874766) was genome-wide significant in the meta-analysis (p=1·58 × 10−8), and encodes an aminoacid change (Pro67Ala) in MSH3. In TRACK-HD, each copy of the minor allele at this SNP was associated with a 0·4 units per year (95% CI 0·16–0·66) reduction in the rate of change of the Unified Huntington's Disease Rating Scale (UHDRS) Total Motor Score, and a reduction of 0·12 units per year (95% CI 0·06–0·18) in the rate of change of UHDRS Total Functional Capacity score. These associations remained significant after adjusting for age of onset. Interpretation The multidomain progression measure in TRACK-HD was associated with a functional variant that was genome-wide significant in our meta-analysis. The association in only 216 participants implies that the progression measure is a sensitive reflection of disease burden, that the effect size at this locus is large, or both. Knockout of Msh3 reduces somatic expansion in Huntington's disease mouse models, suggesting this mechanism as an area for future therapeutic investigation
Development of high performance multifilamentary Nb-Ti-Ta superconductor for LHC insertion quadrupoles
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International study to develop the WOUND-Q patient-reported outcome measure for all types of chronic wounds
Patient-reported outcome measures (PROMs) for chronic wounds mainly focus on specific types of wounds. Our team developed the WOUND-Q for use with all types of wounds in any anatomic location. We conducted 60 concept elicitation interviews with patients in Canada, Denmark, the Netherlands, and the United States. Analysis identified concepts of interest to patients and scales were formed and refined through cognitive interviews with 20 patients and input from 26 wound care experts. Scales were translated into Danish and Dutch. An international field-test study collected data from 881 patients (1020 assessments) with chronic wounds. Rasch measurement theory (RMT) analysis was used to refine the scales and examine psychometric properties. RMT analysis supported the reliability and validity of 13 WOUND-Q scales that measure wound characteristics (assessment, discharge, and smell), health-related quality of life (life impact, psychological, sleep impact, and social), experience of care (information, home care nurses, medical team, and office staff), and wound treatment (dressing and suction device). The WOUND-Q can be used to measure outcomes in research and clinical practice from the perspective of patients with any type of wound.</p