145 research outputs found

    Structural rearrangements underlying ligand-gating in Kir channels

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    Inward rectifier potassium (Kir) channels are physiologically regulated by a wide range of ligands that all act on a common gate, although structural details of gating are unclear. Here we show, using small molecule fluorescent probes attached to introduced cysteines, the molecular motions associated with gating of KirBac1.1 channels. The accessibility of the probes indicates a major barrier to fluorophore entry to the inner cavity. Changes in FRET between fluorophores attached to KirBac1.1 tetramers show that PIP(2)-induced closure involves tilting and rotational motions of secondary structural elements of the cytoplasmic domain that couple ligand binding to a narrowing of the cytoplasmic vestibule. The observed ligand-dependent conformational changes in KirBac1.1 provide a general model for ligand-induced Kir channel gating at the molecular level

    Secondary anionic phospholipid binding site and gating mechanism in Kir2.1 inward rectifier channels

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    Inwardly rectifying potassium (Kir) channels regulate multiple tissues. All Kir channels require interaction of phosphatidyl-4,5-bisphosphate (PIP(2)) at a crystallographically identified binding site, but an additional nonspecific secondary anionic phospholipid (PL(−)) is required to generate high PIP(2) sensitivity of Kir2 channel gating. The PL(−)-binding site and mechanism are yet to be elucidated. Here we report docking simulations that identify a putative PL(−)-binding site, adjacent to the PIP(2)-binding site, generated by two lysine residues from neighbouring subunits. When either lysine is mutated to cysteine (K64C and K219C), channel activity is significantly decreased in cells and in reconstituted liposomes. Directly tethering K64C to the membrane by modification with decyl-MTS generates high PIP(2) sensitivity in liposomes, even in the complete absence of PL(−)s. The results provide a coherent molecular mechanism whereby PL(−) interaction with a discrete binding site results in a conformational change that stabilizes the high-affinity PIP(2) activatory site

    Learning from the children : exploring preschool children's encounters with ICT at home

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    This paper is an account of our attempts to understand preschool children's experiences with information and communication technologies (ICT) at home. Using case study data, we focus on what we can learn from talking directly to the children that might otherwise have been overlooked and on describing and evaluating the methods we adopted to ensure that we maximised the children's contributions to the research. By paying attention to the children's perspectives we have learned that they are discriminating users of ICT who evaluate their own performances, know what gives them pleasure and who differentiate between operational competence and the substantive activities made possible by ICT

    Structural basis of control of inward rectifier Kir2 channel gating by bulk anionic phospholipids

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    Inward rectifier potassium (Kir) channel activity is controlled by plasma membrane lipids. Phosphatidylinositol-4,5-bisphosphate (PIP(2)) binding to a primary site is required for opening of classic inward rectifier Kir2.1 and Kir2.2 channels, but interaction of bulk anionic phospholipid (PL(−)) with a distinct second site is required for high PIP(2) sensitivity. Here we show that introduction of a lipid-partitioning tryptophan at the second site (K62W) generates high PIP(2) sensitivity, even in the absence of PL(−). Furthermore, high-resolution x-ray crystal structures of Kir2.2[K62W], with or without added PIP(2) (2.8- and 2.0-Å resolution, respectively), reveal tight tethering of the C-terminal domain (CTD) to the transmembrane domain (TMD) in each condition. Our results suggest a refined model for phospholipid gating in which PL(−) binding at the second site pulls the CTD toward the membrane, inducing the formation of the high-affinity primary PIP(2) site and explaining the positive allostery between PL(−) binding and PIP(2) sensitivity

    Manual / Issue 3 / Circus

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    Manual, a journal about art and its making. Circus. The third issue centers on the theme of Circus. Includes analyses of various pieces in the museum\u27s archive, a fold-out poster by Jim Drain, and a selection of artworks owned by the museum that loosely address said theme. Softcover, 62 pages. Published 2014 by the RISD Museum. Manual 3 (Circus) contributors include Gina Borromeo, Alison W. Chang, Michelle Clayton, Jim Drain, Daniel Heyman, Andrew Martinez, Ellen McBreen, Thangam Ravindranathan, Rebecca Schneider, Susan Smulyan, and Gwen Strahle.https://digitalcommons.risd.edu/risdmuseum_journals/1002/thumbnail.jp

    Clinical effectiveness of drop-in mental health services at paediatric hospitals: A non-randomised multi-site study for children and young people and their families – study protocol

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    Background: Despite the high prevalence of mental health difficulties in children and young people with long-term health conditions (LTCs), these difficulties and experiences are often overlooked and untreated. Previous research demonstrated the effectiveness of psychological support provided via a drop-in mental health centre located in a paediatric hospital. The aim of this prospective non-randomised single-arm multi-centre interventional study is to determine the clinical effectiveness of drop-in mental health services when implemented at paediatric hospitals in England. Methods: It is hypothesised that families who receive psychological interventions through the drop-in services will show improved emotional and behavioural symptoms. Outcomes will be measured at baseline and at 6-month follow-up. The primary outcome is the difference in the total difficulties score on the Strengths and Difficulties Questionnaire (SDQ) reported by parent or child at 6 months. Secondary outcomes include self and parent reported Paediatric Quality of Life Inventory (PedsQL), self-reported depression (PHQ-9) and anxiety measures (GAD-7) and family satisfaction (CSQ-8). Discussion: This trial aims to determine the clinical effectiveness of providing psychological support in the context of LTCs through drop-in mental health services at paediatric hospitals in England. These findings will contribute to policies and practice addressing mental health needs in children and young people with other long-term health conditions

    Clinical effectiveness of the psychological therapy Mental Health Intervention for Children with Epilepsy in addition to usual care compared with assessment-enhanced usual care alone: a multicentre, randomised controlled clinical trial in the UK

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    BACKGROUND: Mental health difficulties are common in children and young people with chronic health conditions, but many of those in need do not access evidence-based psychological treatments. The study aim was to evaluate the clinical effectiveness of integrated mental health treatment for children and young people with epilepsy, a common chronic health condition known to be associated with a particularly high rate of co-occurring mental health difficulties. METHODS: We conducted a parallel group, multicentre, open-label, randomised controlled trial of participants aged 3-18 years, attending epilepsy clinics across England and Northern Ireland who met diagnostic criteria for a common mental health disorder. Participants were randomised (1:1; using an independent web-based system) to receive the Mental Health Intervention for Children with Epilepsy (MICE) in addition to usual care, or assessment-enhanced usual care alone (control). Children and young people in both groups received a full diagnostic mental health assessment. MICE was a modular psychological intervention designed to treat common mental health conditions in children and young people using evidence-based approaches such as cognitive behaviour therapy and behavioural parenting strategies. Usual care for mental health disorders varied by site but typically included referral to appropriate services. Participants, along with their caregivers, and clinicians were not masked to treatment allocation but statisticians were masked until the point of analysis. The primary outcome, analysed by modified intention-to-treat, was the parent-report Strengths and Difficulties Questionnaire (SDQ) at 6 months post-randomisation. The study is complete and registered with ISRCTN (57823197). FINDINGS: 1401 young people were potentially deemed eligible for study inclusion. Following the exclusion of 531 young people, 870 participants were assessed for eligibility and completed the SDQ, and 480 caregivers provided consent for study inclusion between May 20, 2019, and Jan 31, 2022. Between Aug 28, 2019, and Feb 21, 2022, 334 participants (mean ages 10·5 years [SD 3·6] in the MICE group vs 10·3 [4·0] in control group at baseline) were randomly assigned to an intervention using minimisation balanced by age, primary mental health disorder, diagnosis of intellectual disability, and autistic spectrum disorder at baseline. 168 (50%) of the participants were female and 166 (50%) were male. 166 participants were randomly assigned to the MICE group and 168 were randomly assigned to the control group. At 6 months, the mean SDQ difficulties for the 148 participants in the MICE group was 17·6 (SD 6·3) and 19·6 (6·1) for the 148 participants in the control group. The adjusted effect of MICE was -1·7 (95% CI -2·8 to -0·5; p=0·0040; Cohen's d, 0·3). 14 (8%) patients in the MICE group experienced at least one serious adverse event compared with 24 (14%) in the control group. 68% percent of serious adverse events (50 events) were admission due to seizures. INTERPRETATION: MICE was superior to assessment-enhanced usual care in improving symptoms of emotional and behavioural difficulties in young people with epilepsy and common mental health disorders. The trial therefore shows that mental health comorbidities can be effectively and safely treated by a variety of clinicians, utilising an integrated intervention across ages and in the context of intellectual disability and autism. The evidence from this trial suggests that such a model should be fully embedded in epilepsy services and serves as a model for other chronic health conditions in young people. FUNDING: UK National Institute for Health Research Programme Grants for Applied Research programme and Epilepsy Research UK Endeavour Project Grant
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