211 research outputs found

    Real time quaking-induced conversion analysis of cerebrospinal fluid in sporadic Creutzfeldt-Jakob disease

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    OBJECTIVE: Current cerebrospinal fluid (CSF) tests for sporadic Creutzfeldt-Jakob disease (sCJD) are based on the detection of surrogate markers of neuronal damage such as CSF 14-3-3 which are not specific for sCJD. A number of prion protein conversion assays have been developed, including real-time quaking induced conversion (RT-QuIC). The objective of this study is to investigate whether CSF RT-QuIC analysis could be used as a diagnostic test in sCJD. METHODS: An exploratory study was undertaken which analysed 108 CSF samples from patients with neuropathologically confirmed sCJD or from control patients. Of the 108 CSF samples 56 were from sCJD patients (30 female, 26 male, aged 31–84 years; 62.3 ± 13.5 years) and 52 were from control patients (26 female, 26 male, aged 43–84 years; 67.8 ± 10.4 years). A confirmatory group of 118 patients were subsequently examined which consisted of 67 cases of neuropathologically confirmed sCJD (33 female, 34 male, aged 39–82 years; 67.5 ± 9.0 years) and 51 control cases (26 female, 25 male, aged 36–87 years; 63.5 ± 11.6 years). RESULTS: The exploratory study showed that RT-QuIC analysis had a sensitivity of 91% and a specificity of 98% for the diagnosis of sCJD. These results were confirmed in the confirmatory study which showed that CSF RT-QuIC analysis had a sensitivity and specificity of 87% and 100% respectively. INTERPRETATION: This study shows that CSF RT-QuIC analysis has the potential to be a more specific diagnostic test for sCJD than current CSF tests

    The Fossil Calibration Database—A New Resource for Divergence Dating

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    Fossils provide the principal basis for temporal calibrations, which are critical to the accuracy of divergence dating analyses. Translating fossil data into minimum and maximum bounds for calibrations is the most important—often least appreciated—step of divergence dating. Properly justified calibrations require the synthesis of phylogenetic, paleontological, and geological evidence and can be difficult for nonspecialists to formulate. The dynamic nature of the fossil record (e.g., new discoveries, taxonomic revisions, updates of global or local stratigraphy) requires that calibration data be updated continually lest they become obsolete. Here, we announce the Fossil Calibration Database (http://fossilcalibrations.org), a new open-access resource providing vetted fossil calibrations to the scientific community. Calibrations accessioned into this database are based on individual fossil specimens and follow best practices for phylogenetic justification and geochronological constraint. The associated Fossil Calibration Series, a calibration-themed publication series at Palaeontologia Electronica, will serve as a key pipeline for peer-reviewed calibrations to enter the databas

    Markers of early changes in cognition across cohorts of adults with Down syndrome at risk of Alzheimer's disease.

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    IntroductionDown syndrome (DS), a genetic variant of early onset Alzheimer's disease (AD), lacks a suitable outcome measure for prevention trials targeting pre-dementia stages.MethodsWe used cognitive test data collected in several longitudinal aging studies internationally from 312 participants with DS without dementia to identify composites that were sensitive to change over time. We then conducted additional analyses to provide support for the utility of the composites. The composites were presented to an expert panel to determine the most optimal cognitive battery based on predetermined criteria.ResultsThere were common cognitive domains across site composites, which were sensitive to early decline. The final composite consisted of memory, language/executive functioning, selective attention, orientation, and praxis tests.DiscussionWe have identified a composite that is sensitive to early decline and thus may have utility as an outcome measure in trials to prevent or delay symptoms of AD in DS

    Health service needs and perspectives of remote forest communities in Papua New Guinea: study protocol for combined clinical and rapid anthropological assessments with parallel treatment of urgent cases

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    Introduction Our project follows community requests for health service incorporation into conservation collaborations in the rainforests of Papua New Guinea (PNG). This protocol is for health needs assessments, our first step in coplanning medical provision in communities with no existing health data. Methods and analysis The study includes clinical assessments and rapid anthropological assessment procedures (RAP) exploring the health needs and perspectives of partner communities in two areas, conducted over 6 weeks fieldwork. First, in Wanang village (population c.200), which is set in lowland rainforest. Second, in six communities (population c.3000) along an altitudinal transect up the highest mountain in PNG, Mount Wilhelm. Individual primary care assessments incorporate physical examinations and questioning (providing qualitative and quantitative data) while RAP includes focus groups, interviews and field observations (providing qualitative data). Given absence of in-community primary care, treatments are offered alongside research activity but will not form part of the study. Data are collected by a research fellow, primary care clinician and two PNG research technicians. After quantitative and qualitative analyses, we will report: ethnoclassifications of disease, causes, symptoms and perceived appropriate treatment; community rankings of disease importance and service needs; attitudes regarding health service provision; disease burdens and associations with altitudinal-related variables and cultural practices. To aid wider use study tools are in online supplemental file, and paper and ODK versions are available free from the corresponding author. Ethics and dissemination Challenges include supporting informed consent in communities with low literacy and diverse cultures, moral duties to provide treatment alongside research in medically underserved areas while minimising risks of therapeutic misconception and inappropriate inducement, and PNG research capacity building. Brighton and Sussex Medical School (UK), PNG Institute of Medical Research and PNG Medical Research Advisory Committee have approved the study. Dissemination will be via journals, village meetings and plain language summaries

    The fractured Moon: Production and saturation of porosity in the lunar highlands from impact cratering

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    We have analyzed the Bouguer anomaly (BA) of ~1200 complex craters in the lunar highlands from Gravity Recovery and Interior Laboratory observations. The BA of these craters is generally negative, though positive BA values are observed, particularly for smaller craters. Crater BA values scale inversely with crater diameter, quantifying how larger impacts produce more extensive fracturing and dilatant bulking. The Bouguer anomaly of craters larger than urn:x-wiley:00948276:media:grl53324:grl53324-math-0001 km in diameter is independent of crater size, indicating that there is a limiting depth to impact‐generated porosity, presumably from pore collapse associated with either overburden pressure or viscous flow. Impact‐generated porosity of the bulk lunar crust is likely in a state of equilibrium for craters smaller than ~30 km in diameter, consistent with an ~8 km thick lunar megaregolith, whereas the gravity signature of larger craters is still preserved and provides new insight into the cratering record of even the oldest lunar surfaces

    Loss of Caveolin-1 Accelerates Neurodegeneration and Aging

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    The aged brain exhibits a loss in gray matter and a decrease in spines and synaptic densities that may represent a sequela for neurodegenerative diseases such as Alzheimer's. Membrane/lipid rafts (MLR), discrete regions of the plasmalemma enriched in cholesterol, glycosphingolipids, and sphingomyelin, are essential for the development and stabilization of synapses. Caveolin-1 (Cav-1), a cholesterol binding protein organizes synaptic signaling components within MLR. It is unknown whether loss of synapses is dependent on an age-related loss of Cav-1 expression and whether this has implications for neurodegenerative diseases such as Alzheimer's disease.We analyzed brains from young (Yg, 3-6 months), middle age (Md, 12 months), aged (Ag, >18 months), and young Cav-1 KO mice and show that localization of PSD-95, NR2A, NR2B, TrkBR, AMPAR, and Cav-1 to MLR is decreased in aged hippocampi. Young Cav-1 KO mice showed signs of premature neuronal aging and degeneration. Hippocampi synaptosomes from Cav-1 KO mice showed reduced PSD-95, NR2A, NR2B, and Cav-1, an inability to be protected against cerebral ischemia-reperfusion injury compared to young WT mice, increased Aβ, P-Tau, and astrogliosis, decreased cerebrovascular volume compared to young WT mice. As with aged hippocampi, Cav-1 KO brains showed significantly reduced synapses. Neuron-targeted re-expression of Cav-1 in Cav-1 KO neurons in vitro decreased Aβ expression.Therefore, Cav-1 represents a novel control point for healthy neuronal aging and loss of Cav-1 represents a non-mutational model for Alzheimer's disease

    The Fossil Calibration Database, A New Resource for Divergence Dating

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    Fossils provide the principal basis for temporal calibrations, which are critical to the accuracy of divergence dating analyses. Translating fossil data into minimum and maximum bounds for calibrations is the most important, and often least appreciated, step of divergence dating. Properly justified calibrations require the synthesis of phylogenetic, paleontological, and geological evidence and can be difficult for non- specialists to formulate. The dynamic nature of the fossil record (e.g., new discoveries, taxonomic revisions, updates of global or local stratigraphy) requires that calibration data be updated continually lest they become obsolete. Here, we announce the Fossil Calibration Database (http://fossilcalibrations.org), a new open- access resource providing vetted fossil calibrations to the scientific community. Calibrations accessioned into this database are based on individual fossil specimens and follow best practices for phylogenetic justification and geochronological constraint. The associated Fossil Calibration Series, a calibration-themed publication series at Palaeontologia Electronica, will serve as one key pipeline for peer-reviewed calibrations to enter the database
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