68 research outputs found

    New insights into the genetic etiology of Alzheimer's disease and related dementias

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    Characterization of the genetic landscape of Alzheimer's disease (AD) and related dementias (ADD) provides a unique opportunity for a better understanding of the associated pathophysiological processes. We performed a two-stage genome-wide association study totaling 111,326 clinically diagnosed/'proxy' AD cases and 677,663 controls. We found 75 risk loci, of which 42 were new at the time of analysis. Pathway enrichment analyses confirmed the involvement of amyloid/tau pathways and highlighted microglia implication. Gene prioritization in the new loci identified 31 genes that were suggestive of new genetically associated processes, including the tumor necrosis factor alpha pathway through the linear ubiquitin chain assembly complex. We also built a new genetic risk score associated with the risk of future AD/dementia or progression from mild cognitive impairment to AD/dementia. The improvement in prediction led to a 1.6- to 1.9-fold increase in AD risk from the lowest to the highest decile, in addition to effects of age and the APOE ε4 allele

    Multiancestry analysis of the HLA locus in Alzheimer’s and Parkinson’s diseases uncovers a shared adaptive immune response mediated by HLA-DRB1*04 subtypes

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    Across multiancestry groups, we analyzed Human Leukocyte Antigen (HLA) associations in over 176,000 individuals with Parkinson’s disease (PD) and Alzheimer’s disease (AD) versus controls. We demonstrate that the two diseases share the same protective association at the HLA locus. HLA-specific fine-mapping showed that hierarchical protective effects of HLA-DRB1*04 subtypes best accounted for the association, strongest with HLA-DRB1*04:04 and HLA-DRB1*04:07, and intermediary with HLA-DRB1*04:01 and HLA-DRB1*04:03. The same signal was associated with decreased neurofibrillary tangles in postmortem brains and was associated with reduced tau levels in cerebrospinal fluid and to a lower extent with increased Aβ42. Protective HLA-DRB1*04 subtypes strongly bound the aggregation-prone tau PHF6 sequence, however only when acetylated at a lysine (K311), a common posttranslational modification central to tau aggregation. An HLA-DRB1*04-mediated adaptive immune response decreases PD and AD risks, potentially by acting against tau, offering the possibility of therapeutic avenues

    Preliminary results on surface treatments on wood

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    One of the main issues of the international research project SyMBoL - Sustainable Management of Heritage Buildings in a Long-term perspective, is the evaluation of wood mechanical properties. Particularly, pine wood is tested being the main building materials of medieval Norwegian stave churches. Experiments are aimed to assess variations in mechanical properties as a function of environmental conditions. Being wood highly sensitive to RH% changes, pine slices were maintained at 80% RH (4 weeks, 20°C) and successively treated with the materials here discussed on the two main surfaces; afterward, they were left at 30% RH for three weeks. Thus, the loss of water from the samples is supposed to occur only through the lateral surfaces since the chosen sealing materials were selected on the basis of their capability to avoid any penetration of water into the samples. This work represents, indeed, the study carried out to select materials to be applied on the wooden surfaces. Paraloid B72, also coupled with a cellulose sand seal spray, a microcrystalline wax and an epoxy resin were tested. Obtained surfaces were evaluated in term of water repellency (contact angle measurements), uniformity of the surface; penetration of the materials into the wooden structures, colour and water vapor sorption

    Application of the Guggenheim, Anderson, de Boer (GAB) equation to study the impact of sealing treatments on pine wood sorption characteristics

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    Surface treatments can modify the materials behavior toward water sorption phenomena. The Guggenheim–Andersen–de Boer sorption equation, already used in the past to study various wood species, is here proposed to investigate the sorption behavior of pine wood samples treated with different sealing material. Particularly, the paper aims to explore the modification of the k parameter with the applied coating. Measurements of sorption–desorption branches permitted to clearly distinguish the behavior of treated samples, the relative humidity (RH) conditions over which they are more dimensionally stable, as well as their tendency to swell and shrink. The proposed study permitted to evaluate the usefulness of the k parameter as an indicator of the presence of chemical treatments on wood at high RH values. Particularly, the k value has been found to change as a function of chemicals surface treatments limiting in different ways the access and expulsion of water moisture
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