268 research outputs found

    A dominant mutation within the DNA-binding domain of the bZIP transcription factor Maf causes murine cataract and results in selective alteration in DNA binding

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    The murine autosomal dominant cataract mutants created in mutagenesis experiments have proven to be a powerful resource for modelling the biological processes involved in cataractogenesis. We report a mutant which in the heterozygous state exhibits mild pulverulent cataract named ‘opaque flecks in lens', symbol Ofl. By molecular mapping, followed by a candidate gene approach, the mutant was shown to be allelic with a knockout of the bZIP transcription factor, Maf. Homozygotes for Ofl and for Maf null mutations are similar but a new effect, renal tubular nephritis, was found in Ofl homozygotes surviving beyond 4 weeks, which may contribute to early lethality. Sequencing identified the mutation as a G→A change, leading to the amino-acid substitution mutation R291Q in the basic region of the DNA-binding domain. Since mice heterozygous for knockouts of Maf show no cataracts, this suggests that the Ofl R291Q mutant protein has a dominant effect. We have demonstrated that this mutation results in a selective alteration in DNA binding affinities to target oligonucleotides containing variations in the core CRE and TRE elements. This implies that arginine 291 is important for core element binding and suggests that the mutant protein may exert a differential downstream effect amongst its binding targets. The cataracts seen in Ofl heterozygotes and human MAF mutations are similar to one another, implying that Ofl may be a model of human pulverulent cortical cataract. Furthermore, when bred onto a different genetic background Ofl heterozygotes also show anterior segment abnormalities. The Ofl mutant therefore provides a valuable model system for the study of Maf, and its interacting factors, in normal and abnormal lens and anterior segment developmen

    A Theory of Challenge and Threat States in Athletes: a revised conceptualization

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    The Theory of Challenge and Threat States in Athletes (TCTSA) provides a psychophysiological framework for how athletes anticipate motivated performance situations. The purpose of this review is to discuss how research has addressed the 15 predictions made by the TCTSA, to evaluate the mechanisms underpinning the TCTSA in light of the research that has emerged in the last ten years, and to inform a revised TCTSA (TCTSA-R). There was support for many of the 15 predictions in the TCTSA, with two main areas for reflection identified; to understand the physiology of challenge and to re-evaluate the concept of resource appraisals. This re-evaluation informs the TCTSA-R which elucidates the physiological changes, predispositions, and cognitive appraisals that mark challenge and threat states. First, the relative strength of the sympathetic nervous system response is outlined as a determinant of challenge and threat patterns of reactivity and we suggest that oxytocin and neuropeptide Y are also key indicators of an adaptive approach to motivated performance situations and can facilitate a challenge state. Second, although predispositions were acknowledged within the TCTSA, how these may influence challenge and threat states was not specified. In the TCTSA-R it is proposed that one’s propensity to appraise stressors as a challenge that most strongly dictates acute cognitive appraisals. Third, in the TCTSA-R a more parsimonious integration of Lazarusian ideas of cognitive appraisal and challenge and threat is proposed. Given that an athlete can make both challenge and threat primary appraisals and can have both high or low resources compared to perceived demands, a 2x2 bifurcation theory of challenge and threat is proposed. This reflects polychotomy of four parts; high challenge, low challenge, low threat, and high threat. For example, in low threat, an athlete can evince a threat state but still perform well so long as they perceive high resources. Consequently, we propose suggestions for research concerning measurement tools and a reconsideration of resources to include social support. Finally, applied recommendations are made based on adjusting demands and enhancing resources.N/

    Effectiveness, cost-effectiveness and cost-benefit of a single annual professional intervention for the prevention of childhood dental caries in a remote rural Indigenous community

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    Background The aim of the study is to reduce the high prevalence of tooth decay in children in a remote, rural Indigenous community in Australia, by application of a single annual dental preventive intervention. The study seeks to (1) assess the effectiveness of an annual oral health preventive intervention in slowing the incidence of dental caries in children in this community, (2) identify the mediating role of known risk factors for dental caries and (3) assess the cost-effectiveness and cost-benefit of the intervention. Methods/design The intervention is novel in that most dental preventive interventions require regular re-application, which is not possible in resource constrained communities. While tooth decay is preventable, self-care and healthy habits are lacking in these communities, placing more emphasis on health services to deliver an effective dental preventive intervention. Importantly, the study will assess cost-benefit and cost-effectiveness for broader implementation across similar communities in Australia and internationally. Discussion There is an urgent need to reduce the burden of dental decay in these communities, by implementing effective, cost-effective, feasible and sustainable dental prevention programs. Expected outcomes of this study include improved oral and general health of children within the community; an understanding of the costs associated with the intervention provided, and its comparison with the costs of allowing new lesions to develop, with associated treatment costs. Findings should be generalisable to similar communities around the world. The research is registered with the Australian New Zealand Clinical Trials Registry (ANZCTR), registration number ACTRN12615000693527; date of registration: 3rd July 2015

    Pacing: A Concept Analysis of a Chronic Pain Intervention

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    BACKGROUND: The intervention of pacing is regularly recommended for chronic pain patients. However, pacing is poorly defined and appears to be interpreted in varying, potentially contradictory manners within the field of chronic pain. This conceptual lack of clarity has implications for effective service delivery and for researchers’ ability to conduct rigorous study. An examination of the background literature demonstrates that while pacing is often one part of a multidisciplinary pain management program, outcome research is hindered by a lack of a clear and shared definition of this currently ill-defined construct

    Novel causative mutations in patients with Nance-Horan syndrome and altered localization of the mutant NHS-A protein isoform

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    PURPOSE: Nance-Horan syndrome is typically characterized by severe bilateral congenital cataracts and dental abnormalities. Truncating mutations in the Nance-Horan syndrome (NHS) gene cause this X-linked genetic disorder. NHS encodes two isoforms, NHS-A and NHS-1A. The ocular lens expresses NHS-A, the epithelial and neuronal cell specific isoform. The NHS-A protein localizes in the lens epithelium at the cellular periphery. The data to date suggest a role for this isoform at cell-cell junctions in epithelial cells. This study aimed to identify the causative mutations in new patients diagnosed with Nance-Horan syndrome and to investigate the effect of mutations on subcellular localization of the NHS-A protein. METHODS: All coding exons of NHS were screened for mutations by polymerase chain reaction (PCR) and sequencing. PCR-based mutagenesis was performed to introduce three independent mutations in the NHS-A cDNA. Expression and localization of the mutant proteins was determined in mammalian epithelial cells. RESULTS: Truncating mutations were found in 6 out of 10 unrelated patients from four countries. Each of four patients carried a novel mutation (R248X, P264fs, K1198fs, and I1302fs), and each of the two other patients carried two previously reported mutations (R373X and R879X). No mutation was found in the gene in four patients. Two disease-causing mutations (R134fs and R901X) and an artificial mutation (T1357fs) resulted in premature truncation of the NHS-A protein. All three mutant proteins failed to localize to the cellular periphery in epithelial cells and instead were found in the cytoplasm. CONCLUSIONS: This study brings the total number of mutations identified in NHS to 18. The mislocalization of the mutant NHS-A protein, revealed by mutation analysis, is expected to adversely affect cell-cell junctions in epithelial cells such as the lens epithelium, which may explain cataractogenesis in Nance-Horan syndrome patients. Mutation analysis also shed light on the significance of NHS-A regions for its localization and, hence, its function at epithelial cell junctions.Shiwani Sharma, Kathryn P. Burdon, Alpana Dave, Robyn V. Jamieson, Yuval Yaron, Frank Billson, Lionel Van Maldergem, Birgit Lorenz, Jozef Gécz and Jamie E. Crai

    Research priorities for Inherited Retinal Diseases in Australia: A James Lind Alliance Priority Setting Partnership

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    We undertook Australia’s first James Lind Alliance Priority Setting Partnership to identify research priorities for inherited retinal diseases (IRDs). Adhering to the James Lind Alliance process, our Priority Setting Partnership was guided by our multidisciplinary steering group, involving individuals who have an IRD, caregivers of a child who have an IRD, representatives from relevant community organisations, health professionals, and researchers from across Australia. This report provides a detailed summary of how we undertook our Priority Setting Partnership, followed by commentary on each of the top 10 priorities. Each commentary provides context into the current state of knowledge and highlights opportunities that will drive a meaningful impact for individuals who have an IRD, their caregivers and family, and health professionals across Australia. We conclude with the impact of our Priority Setting Partnership and our next steps

    The Fight Inherited Retinal Blindness! Project: a New Treatment Outcome and Natural History Registry for Inherited Retinal Disease

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    PURPOSE: To design and build a new disease registry to track the natural history and outcomes of approved gene therapy in patients with inherited retinal diseases (IRDs). METHODS: A core committee of 6 members was convened to oversee the construction of the FIRB! module. A further 11 experts formed a steering committee, which discussed disease classification and variables to form minimum datasets via a consensus approach. RESULTS: The web-based FIRB! registry records baseline demographic, clinical and genetic data together with follow-up data. The Human Phenotype Ontology and Monarch Disease Ontology nomenclature were incorporated within the FIRB! architecture to standardise nomenclature. The registry software assigns individual diagnoses to one of 7 broad phenotypic groups, with minimum datasets dependent upon the broad phenotypic group. Additionally, minimum datasets were agreed upon for patients undergoing approved gene therapy with voretigene neparvovec (Luxturna). New patient entries can be completed in 5 minutes, and follow-up data can be entered in 2 minutes. CONCLUSIONS: Fight Inherited Retinal Blindness! (FIRB!) is an organized, web-based system that uses observational study methods to collect uniform data from IRD patients to track natural history and (uniquely) treatment outcomes. It is free to Users, who have control over their data

    AAV capsid bioengineering in primary human retina models

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    Adeno-associated viral (AAV) vector-mediated retinal gene therapy is an active field of both pre-clinical as well as clinical research. As with other gene therapy clinical targets, novel bioengineered AAV variants developed by directed evolution or rational design to possess unique desirable properties, are entering retinal gene therapy translational programs. However, it is becoming increasingly evident that predictive preclinical models are required to develop and functionally validate these novel AAVs prior to clinical studies. To investigate if, and to what extent, primary retinal explant culture could be used for AAV capsid development, this study performed a large high-throughput screen of 51 existing AAV capsids in primary human retina explants and other models of the human retina. Furthermore, we applied transgene expression-based directed evolution to develop novel capsids for more efficient transduction of primary human retina cells and compared the top variants to the strongest existing benchmarks identified in the screening described above. A direct side-by-side comparison of the newly developed capsids in four different in vitro and ex vivo model systems of the human retina allowed us to identify novel AAV variants capable of high transgene expression in primary human retina cells
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