258 research outputs found

    APP Regulates Microglial Phenotype in a Mouse Model of Alzheimer\u27s Disease

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    Prior work suggests that amyloid precursor protein (APP) can function as a proinflammatory receptor on immune cells, such as monocytes and microglia. Therefore, we hypothesized that APP serves this function in microglia during Alzheimer\u27s disease. Although fibrillar amyloid β (Aβ)-stimulated cytokine secretion from both wild-type and APP knock-out (mAPP−/−) microglial cultures, oligomeric Aβ was unable to stimulate increased secretion from mAPP−/− cells. This was consistent with an ability of oligomeric Aβ to bind APP. Similarly, intracerebroventricular infusions of oligomeric Aβ produced less microgliosis in mAPP−/− mice compared with wild-type mice. The mAPP−/− mice crossed to an APP/PS1 transgenic mouse line demonstrated reduced microgliosis and cytokine levels and improved memory compared with wild-type mice despite robust fibrillar Aβ plaque deposition. These data define a novel function for microglial APP in regulating their ability to acquire a proinflammatory phenotype during disease. SIGNIFICANCE STATEMENT A hallmark of Alzheimer\u27s disease (AD) brains is the accumulation of amyloid β (Aβ) peptide within plaques robustly invested with reactive microglia. This supports the notion that Aβ stimulation of microglial activation is one source of brain inflammatory changes during disease. Aβ is a cleavage product of the ubiquitously expressed amyloid precursor protein (APP) and is able to self-associate into a wide variety of differently sized and structurally distinct multimers. In this study, we demonstrate both in vitro and in vivo that nonfibrillar, oligomeric forms of Aβ are able to interact with the parent APP protein to stimulate microglial activation. This provides a mechanism by which metabolism of APP results in possible autocrine or paracrine Aβ production to drive the microgliosis associated with AD brains

    Investigation of the governance structure of Nairobi dairy value chain and its influence on food safety

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    The dairy value chain of Nairobi is comprised, in its majority, of small-scale independent enterprises that operate within a complex interlinked system. In this complexity, the coordination and power structures of the system may have major influences on the management of dairy food safety. Therefore, the aim of this study was to investigate the governance and challenges issues faced by stakeholders throughout the Nairobi dairy value chain and assess their potential implications on food safety. Qualitative data was collected through focus group discussions and key informant interviews based on a dairy value chain mapping framework previously developed. Thematic analysis enabled identification of governance themes, key challenges and their implication on food safety. Themes were organized depending on their association with farmers (informal settlement or peri-urban), dairy cooperatives, dairy traders, processing companies, retailers or government officers. The identified governance themes included: i) weak linkage between government and farmers, ii) inadequate compliance with government regulations by traders and retailers, iii) emphasis on business licenses and permits for revenue rather than for food safety, iv) multiple licensing resulting in high business cost and lack of compliance, v) fragmented regulation, vi) unfair competition and vii) sanctions that do not always result in compliance. The key challenges identified included, amongst others: i) inadequate farmer support, ii) harassment of traders and retailers and iii) high business costs by traders, retailers, dairy cooperatives and large processors. The implication of governance and challenges of food safety were, amongst others: i) inadequate extension services, ii) insufficient cold chain, iii) delivery of adulterated and low milk quality to bulking centres, iv) inadequate food safety training and v) lack of policies for management of waste milk. The range of issues highlighted are based on stakeholders’ perceptions and reflects the complexity of the relationships between them. Many of the governance themes demonstrate the linkages that are both beneficial or confrontational between the formal and informal sectors, and between industry and regulatory authorities, with possible direct food safety consequences. Findings obtained provide indications to decision-makers of potential governance areas that could help improve efficiency and food safety along the dairy value chain

    Estimating the clinical effectiveness and value-based price range of erenumab for the prevention of migraine in patients with prior treatment failures: a US societal perspective

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    BACKGROUND: Frequent migraine with four or more headache days per month is a common, disabling neurovascular disease. From a US societal perspective, this analysis models the clinical efficacy and estimates the value-based price (VBP) for erenumab, a fully human monoclonal antibody that inhibits the calcitonin gene-related peptide receptor. METHODS: A Markov health state transition model was developed to estimate the incremental costs, quality-adjusted life-years (QALYs), and value-based price range for erenumab in migraine prevention. The model comprises "on preventive treatment", "off preventive treatment", and "death" health states across a 10-year time horizon. The evaluation compared erenumab to no preventive treatment in episodic and chronic migraine patients that have failed at least one preventive therapy. Therapeutic benefits are based on estimated changes in monthly migraine days (MMD) from erenumab pivotal clinical trials and a network meta-analysis of migraine studies. Utilities were estimated using previously published mapping algorithms. A VBP analysis was performed to identify maximum erenumab annual prices at willingness-to-pay (WTP) thresholds of 100,000−100,000-200,000 per QALY. Estimates of VBP under different scenarios such as choice of different comparators, assumptions around inclusion of placebo effect, and exclusion of work productivity losses were also generated. RESULTS: Erenumab resulted in incremental QALYs of 0.185 vs supportive care (SC) and estimated cost offsets due to reduced MMD of 8,482over10years,withanaveragedurationoftreatmentof2.01years.TheestimatedVBPatWTPthresholdsof8,482 over 10 years, with an average duration of treatment of 2.01 years. The estimated VBP at WTP thresholds of 100,000-200,000forerenumabcomparedtoSCrangedfrom200,000 for erenumab compared to SC ranged from 14,238-23,998.VBPestimatesincludingtheplaceboeffectandexcludingworkproductivityrangedfrom23,998. VBP estimates including the placebo effect and excluding work productivity ranged from 7,445-13,809;increasingto13,809; increasing to 12,151-$18,589 with onabotulinumtoxinA as a comparator in chronic migraine. CONCLUSION: Erenumab is predicted to reduce migraine-related direct and indirect costs, and increase QALYs compared to SC

    A population of gamma-ray emitting globular clusters seen with the Fermi Large Area Telescope

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    Globular clusters with their large populations of millisecond pulsars (MSPs) are believed to be potential emitters of high-energy gamma-ray emission. Our goal is to constrain the millisecond pulsar populations in globular clusters from analysis of gamma-ray observations. We use 546 days of continuous sky-survey observations obtained with the Large Area Telescope aboard the Fermi Gamma-ray Space Telescope to study the gamma-ray emission towards 13 globular clusters. Steady point-like high-energy gamma-ray emission has been significantly detected towards 8 globular clusters. Five of them (47 Tucanae, Omega Cen, NGC 6388, Terzan 5, and M 28) show hard spectral power indices (0.7<Γ<1.4)(0.7 < \Gamma <1.4) and clear evidence for an exponential cut-off in the range 1.0-2.6 GeV, which is the characteristic signature of magnetospheric emission from MSPs. Three of them (M 62, NGC 6440 and NGC 6652) also show hard spectral indices (1.0<Γ<1.7)(1.0 < \Gamma < 1.7), however the presence of an exponential cut-off can not be unambiguously established. Three of them (Omega Cen, NGC 6388, NGC 6652) have no known radio or X-ray MSPs yet still exhibit MSP spectral properties. From the observed gamma-ray luminosities, we estimate the total number of MSPs that is expected to be present in these globular clusters. We show that our estimates of the MSP population correlate with the stellar encounter rate and we estimate 2600-4700 MSPs in Galactic globular clusters, commensurate with previous estimates. The observation of high-energy gamma-ray emission from a globular cluster thus provides a reliable independent method to assess their millisecond pulsar populations that can be used to make constraints on the original neutron star X-ray binary population, essential for understanding the importance of binary systems in slowing the inevitable core collapse of globular clusters.Comment: Accepted for publication in A&A. Corresponding authors: J. Kn\"odlseder, N. Webb, B. Pancraz

    Mechanisms of congenital heart disease caused by NAA15 haploinsufficiency

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    Rationale: NAA15 is a component of the N-terminal (Nt) acetyltransferase complex, NatA. The mechanism by which NAA15 haploinsufficiency causes congenital heart disease (CHD) remains unknown. To better understand molecular processes by which NAA15 haploinsufficiency perturbs cardiac development, we introduced NAA15 variants into human induced pluripotent stem cells (iPSCs) and assessed the consequences of these mutations on RNA and protein expression. Objective: We aim to understand the role of NAA15 haploinsufficiency in cardiac development by investigating proteomic effects on NatA complex activity, and identifying proteins dependent upon a full amount of NAA15. Methods and Results: We introduced heterozygous LoF, compound heterozygous and missense residues (R276W) in iPS cells using CRISPR/Cas9. Haploinsufficient NAA15 iPS cells differentiate into cardiomyocytes, unlike NAA15-null iPS cells, presumably due to altered composition of NatA. Mass spectrometry (MS) analyses reveal ~80% of identified iPS cell NatA targeted proteins displayed partial or complete Nt-acetylation. Between null and haploinsufficient NAA15 cells Nt-acetylation levels of 32 and 9 NatA-specific targeted proteins were reduced, respectively. Similar acetylation loss in few proteins occurred in NAA15 R276W iPSCs. In addition, steady-state protein levels of 562 proteins were altered in both null and haploinsufficient NAA15 cells; eighteen were ribosomal-associated proteins. At least four proteins were encoded by genes known to cause autosomal dominant CHD. Conclusions: These studies define a set of human proteins that requires a full NAA15 complement for normal synthesis and development. A 50% reduction in the amount of NAA15 alters levels of at least 562 proteins and Nt-acetylation of only 9 proteins. One or more modulated proteins are likely responsible for NAA15-haploinsufficiency mediated CHD. Additionally, genetically engineered iPS cells provide a platform for evaluating the consequences of amino acid sequence variants of unknown significance on NAA15 function

    The Society for Immunotherapy of Cancer consensus statement on immunotherapy for the treatment of hematologic malignancies: multiple myeloma, lymphoma, and acute leukemia

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    Increasing knowledge concerning the biology of hematologic malignancies as well as the role of the immune system in the control of these diseases has led to the development and approval of immunotherapies that are resulting in impressive clinical responses. Therefore, the Society for Immunotherapy of Cancer (SITC) convened a hematologic malignancy Cancer Immunotherapy Guidelines panel consisting of physicians, nurses, patient advocates, and patients to develop consensus recommendations for the clinical application of immunotherapy for patients with multiple myeloma, lymphoma, and acute leukemia. These recommendations were developed following the previously established process based on the Institute of Medicine’s clinical practice guidelines. In doing so, a systematic literature search was performed for high-impact studies from 2004 to 2014 and was supplemented with further literature as identified by the panel. The consensus panel met in December of 2014 with the goal to generate consensus recommendations for the clinical use of immunotherapy in patients with hematologic malignancies. During this meeting, consensus panel voting along with discussion were used to rate and review the strength of the supporting evidence from the literature search. These consensus recommendations focus on issues related to patient selection, toxicity management, clinical endpoints, and the sequencing or combination of therapies. Overall, immunotherapy is rapidly emerging as an effective therapeutic strategy for the management of hematologic malignances. Evidence-based consensus recommendations for its clinical application are provided and will be updated as the field evolves

    Development and implementation of guidelines for the management of depression: a systematic review

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    Objective: To evaluate the development and implementation of clinical practice guidelines for the management of depression globally. Methods: We conducted a systematic review of existing guidelines for the management of depression in adults with major depressive or bipolar disorder. For each identified guideline, we assessed compliance with measures of guideline development quality (such as transparency in guideline development processes and funding, multidisciplinary author group composition, systematic review of comparative efficacy research) and implementation (such as quality indicators). We compared guidelines from low- and middle-income countries with those from high-income countries. Findings: We identified 82 national and 13 international clinical practice guidelines from 83 countries in 27 languages. Guideline development processes and funding sources were explicitly specified in a smaller proportion of guidelines from low- and middle-income countries (8/29; 28%) relative to high-income countries (35/58; 60%). Fewer guidelines (2/29; 7%) from low- and middle-income countries, relative to high-income countries (22/58; 38%), were authored by a multidisciplinary development group. A systematic review of comparative effectiveness was conducted in 31% (9/29) of low- and middle-income country guidelines versus 71% (41/58) of high-income country guidelines. Only 10% (3/29) of low- and middle-income country and 19% (11/58) of high-income country guidelines described plans to assess quality indicators or recommendation adherence. Conclusion: Globally, guideline implementation is inadequately planned, reported and measured. Narrowing disparities in the development and implementation of guidelines in low- and middle-income countries is a priority. Future guidelines should present strategies to implement recommendations and measure feasibility, cost-effectiveness and impact on health outcomes

    A Novel Role for Mc1r in the Parallel Evolution of Depigmentation in Independent Populations of the Cavefish Astyanax mexicanus

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    The evolution of degenerate characteristics remains a poorly understood phenomenon. Only recently has the identification of mutations underlying regressive phenotypes become accessible through the use of genetic analyses. Focusing on the Mexican cave tetra Astyanax mexicanus, we describe, here, an analysis of the brown mutation, which was first described in the literature nearly 40 years ago. This phenotype causes reduced melanin content, decreased melanophore number, and brownish eyes in convergent cave forms of A. mexicanus. Crosses demonstrate non-complementation of the brown phenotype in F2 individuals derived from two independent cave populations: Pachón and the linked Yerbaniz and Japonés caves, indicating the same locus is responsible for reduced pigmentation in these fish. While the brown mutant phenotype arose prior to the fixation of albinism in Pachón cave individuals, it is unclear whether the brown mutation arose before or after the fixation of albinism in the linked Yerbaniz/Japonés caves. Using a QTL approach combined with sequence and functional analyses, we have discovered that two distinct genetic alterations in the coding sequence of the gene Mc1r cause reduced pigmentation associated with the brown mutant phenotype in these caves. Our analysis identifies a novel role for Mc1r in the evolution of degenerative phenotypes in blind Mexican cavefish. Further, the brown phenotype has arisen independently in geographically separate caves, mediated through different mutations of the same gene. This example of parallelism indicates that certain genes are frequent targets of mutation in the repeated evolution of regressive phenotypes in cave-adapted species
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