Dissecting a Charged Network at the Active Site of Orotidine-5′-phosphate Decarboxylase

The crystal structure of yeast orotidine-5'-phosphate decarboxylase in complex with the postulated transition state analog, 6-hydroxyuridine-5'-phosphate, reveals contacts between this inhibitor and a novel quartet of charged residues (Lys-59, Asp-91, Lys-93, and Asp-96) within the active site. The structure also suggests a possible interaction between O2 of the 6-hydroxyuridine-5'-phosphate pyrimidine ring and Gln-215. Here we report the results of mutagenesis of each of the charged active site residues and Gln-215. The activities of the Q215A and wild-type enzymes were equal indicating that any interactions between this residue and the pyrimidine ring are dispensable for efficient decarboxylation. For the D91A and K93A mutant enzymes, activity was reduced by more than 5 orders of magnitude and substrate binding could not be detected by isothermal calorimetry. For the D96A mutant enzyme, k(cat) was reduced by more than 5 orders of magnitude, and isothermal calorimetry indicated an 11-fold decrease in the affinity of this enzyme for the substrate in the ground state. For the K59A enzyme, k(cat) was reduced by a factor of 130, and K(m) had increased by a factor of 900. These results indicate that the integrity of the network of charged residues is essential for transition state stabilization

The relationship between occupational demands and well-being of performing artists: A systematic review

Background: Performing artists are exposed to a range of occupational demands from organisational, interpersonal and intrapersonal sources, which may impact their well-being. The aim of this systematic review was to evaluate and synthesise the literature where researchers have considered the relationship between occupational demands and well-being in performing artists. Methods: A mixed-methods systematic review was conducted including professional and student performing artists. Quantitative, qualitative and mixed-methods study designs were eligible for inclusion in the review. A total of 14 databases were searched from their inception through to October 2017, including MEDLINE, EMBASE and Scopus. Critical appraisal was conducted using the Mixed-Methods Appraisal Tool and results presented as a narrative synthesis. Results: A total of 20 studies were included in the review, comprising of quantitative (n=7), qualitative (n=9) and mixed-methods (n=4) study designs. Several frameworks of occupational stress and well-being were explored in relation to the results. Organisational, social and emotional demands were associated with lower well-being. Conversely, music-making, performance activities and social support were reported to be resources and were related to higher well-being. Conclusion: This systematic review highlights the need for researchers in this field to adopt methodologically robust study designs, which are informed by appropriate theoretical frameworks. The paucity of high quality and theoretically informed research in this area is a hindrance to the development of evidence-based interventions for this population

Evidence for models of diagnostic service provision in the community: literature mapping exercise and focused rapid reviews

Background Current NHS policy favours the expansion of diagnostic testing services in community and primary care settings. Objectives Our objectives were to identify current models of community diagnostic services in the UK and internationally and to assess the evidence for quality, safety and clinical effectiveness of such services. We were also interested in whether or not there is any evidence to support a broader range of diagnostic tests being provided in the community. Review methods We performed an initial broad literature mapping exercise to assess the quantity and nature of the published research evidence. The results were used to inform selection of three areas for investigation in more detail. We chose to perform focused reviews on logistics of diagnostic modalities in primary care (because the relevant issues differ widely between different types of test); diagnostic ultrasound (a key diagnostic technology affected by developments in equipment); and a diagnostic pathway (assessment of breathlessness) typically delivered wholly or partly in primary care/community settings. Databases and other sources searched, and search dates, were decided individually for each review. Quantitative and qualitative systematic reviews and primary studies of any design were eligible for inclusion. Results We identified seven main models of service that are delivered in primary care/community settings and in most cases with the possible involvement of community/primary care staff. Not all of these models are relevant to all types of diagnostic test. Overall, the evidence base for community- and primary care-based diagnostic services was limited, with very few controlled studies comparing different models of service. We found evidence from different settings that these services can reduce referrals to secondary care and allow more patients to be managed in primary care, but the quality of the research was generally poor. Evidence on the quality (including diagnostic accuracy and appropriateness of test ordering) and safety of such services was mixed. Conclusions In the absence of clear evidence of superior clinical effectiveness and cost-effectiveness, the expansion of community-based services appears to be driven by other factors. These include policies to encourage moving services out of hospitals; the promise of reduced waiting times for diagnosis; the availability of a wider range of suitable tests and/or cheaper, more user-friendly equipment; and the ability of commercial providers to bid for NHS contracts. However, service development also faces a number of barriers, including issues related to staffing, training, governance and quality control. Limitations We have not attempted to cover all types of diagnostic technology in equal depth. Time and staff resources constrained our ability to carry out review processes in duplicate. Research in this field is limited by the difficulty of obtaining, from publicly available sources, up-to-date information about what models of service are commissioned, where and from which providers. Future work There is a need for research to compare the outcomes of different service models using robust study designs. Comparisons of ‘true’ community-based services with secondary care-based open-access services and rapid access clinics would be particularly valuable. There are specific needs for economic evaluations and for studies that incorporate effects on the wider health system. There appears to be no easy way of identifying what services are being commissioned from whom and keeping up with local evaluations of new services, suggesting a need to improve the availability of information in this area. Funding The National Institute for Health Research Health Services and Delivery Research programme

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Glycodendrimers and Modified ELISAs: Tools to Elucidate Multivalent Interactions of Galectins 1 and 3

Multivalent protein-carbohydrate interactions that are mediated by sugar-binding proteins, i.e., lectins, have been implicated in a myriad of intercellular recognition processes associated with tumor progression such as galectin-mediated cancer cellular migration/metastatic processes. Here, using a modified ELISA, we show that glycodendrimers bearing mixtures of galactosides, lactosides, and N-acetylgalactosaminosides, galectin-3 ligands, multivalently affect galectin-3 functions. We further demonstrate that lactose functionalized glycodendrimers multivalently bind a different member of the galectin family, i.e., galectin-1. In a modified ELISA, galectin-3 recruitment by glycodendrimers was shown to directly depend on the ratio of low to high affinity ligands on the dendrimers, with lactose-functionalized dendrimers having the highest activity and also binding well to galectin-1. The results depicted here indicate that synthetic multivalent systems and upfront assay formats will improve the understanding of the multivalent function of galectins during multivalent protein carbohydrate recognition/interaction

Duty of care or duty to care? What determines our responsibilities at work?

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