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1.
  • 2021
  • swepub:Mat__t
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2.
  • Glasbey, JC, et al. (författare)
  • 2021
  • swepub:Mat__t
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  • Garcia-Benito, R., et al. (författare)
  • CALIFA, the Calar Alto Legacy Integral Field Area survey III. Second public data release
  • 2015
  • Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 576:A135
  • Tidskriftsartikel (refereegranskat)abstract
    • This paper describes the Second Public Data Release (DR2) of the Calar Alto Legacy Integral Field Area (CALIFA) survey. The data for 200 objects are made public, including the 100 galaxies of the First Public Data Release (DR1). Data were obtained with the integral-field spectrograph PMAS /PPak mounted on the 3.5 m telescope at the Calar Alto observatory. Two different spectral setups are available for each galaxy, (i) a low-resolution V500 setup covering the wavelength range 3745-7500 angstrom with a spectral resolution of 6.0 angstrom (FWHM); and (ii) a medium-resolution V1200 setup covering the wavelength range 3650-4840 angstrom with a spectral resolution of 2.3 angstrom (FWHM). The sample covers a redshift range between 0.005 and 0.03, with a wide range of properties in the color-magnitude diagram, stellar mass, ionization conditions, and morphological types. All the cubes in the data release were reduced with the latest pipeline, which includes improved spectrophotometric calibration, spatial registration, and spatial resolution. The spectrophotometric calibration is better than 6% and the median spatial resolution is 2 4. In total, the second data release contains over 1.5 million spectra.
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8.
  • Gómez, M., et al. (författare)
  • From agroindustries to integrated biomass logistics centres. Agroinlog project : Summary of final results
  • 2020
  • Ingår i: European Biomass Conference and Exhibition Proceedings. - : ETA-Florence Renewable Energies. ; , s. 941-952
  • Konferensbidrag (refereegranskat)abstract
    • AGROinLOG project has tested the integrated biomass logistics centres (IBLC) concept in three real agro-industries in Europe. The relevance of the IBLC strategy relies on the fact that it allows agro-industries to create a new activity with lower investment, increasing incomes, stabilizing their annual activity (avoiding idle periods) and maintaining or creating new jobs. The demos’ studies were performed in Spain at a fodder industry, in Greece at an olive oil industry, and in Sweden inside a cereal processing industry. AGROinLOG validated these demos´ business models from a holistic perspective, also studying the replicability of the IBLC business model in other agro-industries from different sectors (vegetable oil extraction, olive oil chain, feed & fodder, wine, grain chain and sugar industry). Sectorial analysis was carried out as well, allowing the identification of opportunities among the targeted sector to replicate the IBLC concept, drawing barriers to overcome in each case. Thus, technical, economic and environmental feasibility of integrated biomass logistics centers (IBLCs) for food and non-food products have been assessed in detail. 
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9.
  • Pathan, M., et al. (författare)
  • A novel community driven software for functional enrichment analysis of extracellular vesicles data
  • 2017
  • Ingår i: Journal of Extracellular Vesicles. - : Wiley. - 2001-3078. ; 6:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Bioinformatics tools are imperative for the in depth analysis of heterogeneous high-throughput data. Most of the software tools are developed by specific laboratories or groups or companies wherein they are designed to perform the required analysis for the group. However, such software tools may fail to capture "what the community needs in a tool". Here, we describe a novel community-driven approach to build a comprehensive functional enrichment analysis tool. Using the existing FunRich tool as a template, we invited researchers to request additional features and/or changes. Remarkably, with the enthusiastic participation of the community, we were able to implement 90% of the requested features. FunRich enables plugin for extracellular vesicles wherein users can download and analyse data from Vesiclepedia database. By involving researchers early through community needs software development, we believe that comprehensive analysis tools can be developed in various scientific disciplines.
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10.
  • Clayton, A., et al. (författare)
  • Considerations towards a roadmap for collection, handling and storage of blood extracellular vesicles
  • 2019
  • Ingår i: Journal of Extracellular Vesicles. - : Wiley. - 2001-3078. ; 8:1
  • Tidskriftsartikel (refereegranskat)abstract
    • There is an increasing interest in exploring clinically relevant information that is present in body fluids, and extracellular vesicles (EVs) are intrinsic components of body fluids ("liquid biopsies"). In this report, we will focus on blood. Blood contains not only EVs but also cells, and non-EV particles including lipoproteins. Due to the high concentration of soluble proteins and lipoproteins, blood, plasma and serum have a high viscosity and density, which hampers the concentration, isolation and detection of EVs. Because most if not all studies on EVs are single-centre studies, their clinical relevance remains limited. Therefore, there is an urgent need to improve standardization and reproducibility of EV research. As a first step, the International Society on Extracellular Vesicles organized a biomarker workshop in Birmingham (UK) in November 2017, and during that workshop several working groups were created to focus on a particular body fluid. This report is the first output of the blood EV work group and is based on responses by work group members to a questionnaire in order to discover the contours of a roadmap. From the answers it is clear that most respondents are in favour of evidence-based research, education, quality control procedures, and physical models to improve our understanding and comparison of concentration, isolation and detection methods. Since blood is such a complex body fluid, we assume that the outcome of the survey may also be valuable for exploring body fluids other than blood.
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12.
  • Salvado, G., et al. (författare)
  • Centiloid cut-off values for optimal agreement between PET and CSF core AD biomarkers
  • 2019
  • Ingår i: Alzheimers Research & Therapy. - : Springer Science and Business Media LLC. - 1758-9193. ; 11
  • Tidskriftsartikel (refereegranskat)abstract
    • BackgroundThe Centiloid scale has been developed to standardize measurements of amyloid PET imaging. Reference cut-off values of this continuous measurement enable the consistent operationalization of decision-making for multicentre research studies and clinical trials. In this study, we aimed at deriving reference Centiloid thresholds that maximize the agreement against core Alzheimer's disease (AD) cerebrospinal fluid (CSF) biomarkers in two large independent cohorts.MethodsA total of 516 participants of the ALFA+ Study (N=205) and ADNI (N=311) underwent amyloid PET imaging ([F-18]flutemetamol and [F-18]florbetapir, respectively) and core AD CSF biomarker determination using Elecsys (R) tests. Tracer uptake was quantified in Centiloid units (CL). Optimal Centiloid cut-offs were sought that maximize the agreement between PET and dichotomous determinations based on CSF levels of A(42), tTau, pTau, and their ratios, using pre-established reference cut-off values. To this end, a receiver operating characteristic analysis (ROC) was conducted, and Centiloid cut-offs were calculated as those that maximized the Youden's J Index or the overall percentage agreement recorded.ResultsAll Centiloid cut-offs fell within the range of 25-35, except for CSF A(42) that rendered an optimal cut-off value of 12 CL. As expected, the agreement of tau/A(42) ratios was higher than that of CSF A(42). Centiloid cut-off robustness was confirmed even when established in an independent cohort and against variations of CSF cut-offs.ConclusionsA cut-off of 12 CL matches previously reported values derived against postmortem measures of AD neuropathology. Together with these previous findings, our results flag two relevant inflection points that would serve as boundary of different stages of amyloid pathology: one around 12 CL that marks the transition from the absence of pathology to subtle pathology and another one around 30 CL indicating the presence of established pathology. The derivation of robust and generalizable cut-offs for core AD biomarkers requires cohorts with adequate representation of intermediate levels.Trial registrationALFA+ Study, NCT02485730ALFA PET Sub-study, NCT02685969
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13.
  • Salvado, G., et al. (författare)
  • The protective gene dose effect of the APOE epsilon 2 allele on gray matter volume in cognitively unimpaired individuals
  • 2022
  • Ingår i: Alzheimers & Dementia. - : Wiley. - 1552-5260 .- 1552-5279. ; 18:7, s. 1383-1395
  • Tidskriftsartikel (refereegranskat)abstract
    • Introduction: Harboring two copies of the apolipoprotein E (APOE) epsilon 2 allele strongly protects against Alzheimer's disease (AD). However, the effect of this genotype on gray matter (GM) volume in cognitively unimpaired individuals has not yet been described. Methods: Multicenter brain magnetic resonance images (MRIs) from cognitively unimpaired epsilon 2 homozygotes were matched (1:1) against all other APOE genotypes for relevant confounders (n = 223). GM volumes of epsilon 2 genotypic groups were compared to each other and to the reference group (APOE epsilon 3/epsilon 3). Results: Carrying at least one epsilon 2 allele was associated with larger GM volumes in brain areas typically affected by AD and also in areas associated with cognitive resilience. APOE epsilon 2 homozygotes, but not APOE epsilon 2 heterozygotes, showed larger GM volumes in areas related to successful aging. Discussion: In addition to the known resistance against amyloid-beta deposition, the larger GM volumes in key brain regions may confer APOE epsilon 2 homozygotes additional protection against AD-related cognitive decline.
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14.
  • Welsh, Joshua A., et al. (författare)
  • Minimal information for studies of extracellular vesicles (MISEV2023): From basic to advanced approaches
  • 2024
  • Ingår i: Journal of Extracellular Vesicles. - : John Wiley and Sons Inc. - 2001-3078. ; 13:2
  • Tidskriftsartikel (refereegranskat)abstract
    • Extracellular vesicles (EVs), through their complex cargo, can reflect the state of their cell of origin and change the functions and phenotypes of other cells. These features indicate strong biomarker and therapeutic potential and have generated broad interest, as evidenced by the steady year-on-year increase in the numbers of scientific publications about EVs. Important advances have been made in EV metrology and in understanding and applying EV biology. However, hurdles remain to realising the potential of EVs in domains ranging from basic biology to clinical applications due to challenges in EV nomenclature, separation from non-vesicular extracellular particles, characterisation and functional studies. To address the challenges and opportunities in this rapidly evolving field, the International Society for Extracellular Vesicles (ISEV) updates its ‘Minimal Information for Studies of Extracellular Vesicles’, which was first published in 2014 and then in 2018 as MISEV2014 and MISEV2018, respectively. The goal of the current document, MISEV2023, is to provide researchers with an updated snapshot of available approaches and their advantages and limitations for production, separation and characterisation of EVs from multiple sources, including cell culture, body fluids and solid tissues. In addition to presenting the latest state of the art in basic principles of EV research, this document also covers advanced techniques and approaches that are currently expanding the boundaries of the field. MISEV2023 also includes new sections on EV release and uptake and a brief discussion of in vivo approaches to study EVs. Compiling feedback from ISEV expert task forces and more than 1000 researchers, this document conveys the current state of EV research to facilitate robust scientific discoveries and move the field forward even more rapidly.
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15.
  • Arenaza-Urquijo, E. M., et al. (författare)
  • Association of years to parent's sporadic onset and risk factors with neural integrity and Alzheimer biomarkers
  • 2020
  • Ingår i: Neurology. - : Ovid Technologies (Wolters Kluwer Health). - 0028-3878 .- 1526-632X. ; 95:15
  • Tidskriftsartikel (refereegranskat)abstract
    • Objective To evaluate the hypothesis that proximity to parental age at onset (AAO) in sporadic Alzheimer disease (AD) is associated with greater AD and neural injury biomarker alterations during midlife and to assess the role of nonmodifiable and modifiable factors. Methods This observational study included 290 cognitively unimpaired (CU) participants with a family history (FH) of clinically diagnosed sporadic AD (age 49-73 years) from the Alzheimer's and Families (ALFA) study. [F-18]flutemetamol-PET standardized uptake value ratios, CSF beta-amyloid(42/40) ratio, and phosphorylated tau were used as AD biomarkers. Hippocampal volumes and CSF total tau were used as neural injury biomarkers. Mental and vascular health proxies were calculated. In multiple regression models, we assessed the effect of proximity to parental AAO and its interaction with age on AD and neural injury biomarkers. Then, we evaluated the effects of FH load (number of parents affected), sex, APOE epsilon 4, education, and vascular and mental health. Results Proximity to parental AAO was associated with beta-amyloid, but not with neural injury biomarkers, and interacted with sex and age, showing that women and older participants had increased beta-amyloid. FH load and APOE epsilon 4 showed independent contributions to beta-amyloid load. Education and vascular and mental health proxies were not associated with AD biomarkers. However, lower mental health proxies were associated with decreased hippocampal volumes with age. Conclusion The identification of the earliest biomarker changes and modifiable factors to be targeted in early interventions is crucial for AD prevention. Proximity to parental AAO may offer a timeline for detection of incipient beta-amyloid changes in women. In risk-enriched middle-aged cohorts, mental health may be a target for early interventions.
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16.
  • Clayton, Aled, et al. (författare)
  • Summary of the ISEV workshop on extracellular vesicles as disease biomarkers, held in Birmingham, UK, during December 2017
  • 2018
  • Ingår i: Journal of Extracellular Vesicles. - : Wiley. - 2001-3078. ; 7
  • Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
    • © 2018 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group on behalf of The International Society for Extracellular Vesicles. This report summarises the presentations and activities of the ISEV Workshop on extracellular vesicle biomarkers held in Birmingham, UK during December 2017. Among the key messages was broad agreement about the importance of biospecimen science. Much greater attention needs to be paid towards the provenance of collected samples. The workshop also highlighted clear gaps in our knowledge about pre-analytical factors that alter extracellular vesicles (EVs). The future utility of certified standards for credentialing of instruments and software, to analyse EV and for tracking the influence of isolation steps on the structure and content of EVs were also discussed. Several example studies were presented, demonstrating the potential utility for EVs in disease diagnosis, prognosis, longitudinal serial testing and stratification of patients. The conclusion of the workshop was that more effort focused on pre-analytical issues and benchmarking of isolation methods is needed to strengthen collaborations and advance more effective biomarkers.
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  • Cumplido-Mayoral, I., et al. (författare)
  • Biological brain age prediction using machine learning on structural neuroimaging data: Multi-cohort validation against biomarkers of Alzheimer's disease and neurodegeneration stratified by sex
  • 2023
  • Ingår i: Elife. - 2050-084X. ; 12
  • Tidskriftsartikel (refereegranskat)abstract
    • Brain--age can be inferred from structural neuroimaging and compared to chronological age (brain--age delta) as a marker of biological brain aging. Accelerated aging has been found in neurodegenerative disorders like Alzheimer's disease (AD), but its validation against markers of neurodegeneration and AD is lacking. Here, imaging--derived measures from the UK Biobank dataset (N=22,661) were used to predict brain--age in 2,314 cognitively unimpaired (CU) individuals at higher risk of AD and mild cognitive impaired (MCI) patients from four independent cohorts with available biomarker data: ALFA+, ADNI, EPAD, and OASIS. Brain-age delta was associated with abnormal amyloid-ss, more advanced stages (AT) of AD pathology and APOE-e4 status. Brain--age delta was positively associated with plasma neurofilament light, a marker of neurodegeneration, and sex differences in the brain effects of this marker were found. These results validate brain--age delta as a non-invasive marker of biological brain aging in non--demented individuals with abnormal levels of biomarkers of AD and axonal injury.
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18.
  • Luo, Y. -W, et al. (författare)
  • Database of diazotrophs in global ocean : abundance, biomass and nitrogen fixation rates
  • 2012
  • Ingår i: Earth System Science Data. - : Copernicus GmbH. - 1866-3508 .- 1866-3516. ; 4:1, s. 47-73
  • Tidskriftsartikel (refereegranskat)abstract
    • Marine N-2 fixing microorganisms, termed di-azotrophs, are a key functional group in marine pelagic ecosystems. The biological fixation of dinitrogen ( N-2) to bioavailable nitrogen provides an important new source of nitrogen for pelagic marine ecosystems and influences primary productivity and organic matter export to the deep ocean. As one of a series of efforts to collect biomass and rates specific to different phytoplankton functional groups, we have constructed a database on diazotrophic organisms in the global pelagic upper ocean by compiling about 12 000 direct field measurements of cyanobacterial diazotroph abundances (based on microscopic cell counts or qPCR assays targeting the nifH genes) and N-2 fixation rates. Biomass conversion factors are estimated based on cell sizes to convert abundance data to diazotrophic biomass. The database is limited spatially, lacking large regions of the ocean especially in the Indian Ocean. The data are approximately log-normal distributed, and large variances exist in most sub-databases with non-zero values differing 5 to 8 orders of magnitude. Reporting the geometric mean and the range of one geometric standard error below and above the geometric mean, the pelagic N-2 fixation rate in the global ocean is estimated to be 62 (52-73) Tg Nyr(-1) and the pelagic diazotrophic biomass in the global ocean is estimated to be 2.1 (1.4-3.1) Tg C from cell counts and to 89 (43-150) Tg C from nifH- based abundances. Reporting the arithmetic mean and one standard error instead, these three global estimates are 140 +/- 9.2 Tg Nyr(-1), 18 +/- 1.8 Tg C and 590 +/- 70 Tg C, respectively. Uncertainties related to biomass conversion factors can change the estimate of geometric mean pelagic diazotrophic biomass in the global ocean by about +/- 70 %. It was recently established that the most commonly applied method used to measure N-2 fixation has underestimated the true rates. As a result, one can expect that future rate measurements will shift the mean N-2 fixation rate upward and may result in significantly higher estimates for the global N-2 fixation. The evolving database can nevertheless be used to study spatial and temporal distributions and variations of marine N-2 fixation, to validate geochemical estimates and to parameterize and validate biogeochemical models, keeping in mind that future rate measurements may rise in the future.
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19.
  • Mila-Aloma, M., et al. (författare)
  • Cognitively unimpaired individuals with a low burden of A beta pathology have a distinct CSF biomarker profile
  • 2021
  • Ingår i: Alzheimers Research & Therapy. - : Springer Science and Business Media LLC. - 1758-9193. ; 13:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Understanding the changes that occur in the transitional stage between absent and overt amyloid-beta (A beta) pathology within the Alzheimer's continuum is crucial to develop therapeutic and preventive strategies. The objective of this study is to test whether cognitively unimpaired individuals with a low burden of A beta pathology have a distinct CSF, structural, and functional neuroimaging biomarker profile. Methods: Cross-sectional study of 318 middle-aged, cognitively unimpaired individuals from the ALFA+ cohort. We measured CSF A beta 42/40, phosphorylated tau (p-tau), total tau (t-tau), neurofilament light (NfL), neurogranin, sTREM2, YKL40, GFAP, IL6, S100B, and alpha-synuclein. Participants also underwent cognitive assessments, APOE genotyping, structural MRI, [F-18]-FDG, and [F-18]-flutemetamol PET. To ensure the robustness of our results, we used three definitions of low burden of A beta pathology: (1) positive CSF A beta 42/40 and < 30 Centiloids in A beta PET, (2) positive CSF A beta 42/40 and negative A beta PET visual read, and (3) 20-40 Centiloid range in A beta PET. We tested CSF and neuroimaging biomarker differences between the low burden group and the corresponding A beta-negative group, adjusted by age and sex. Results: The prevalence and demographic characteristics of the low burden group differed between the three definitions. CSF p-tau and t-tau were increased in the low burden group compared to the A beta-negative in all definitions. CSF neurogranin was increased in the low burden group definitions 1 and 3, while CSF NfL was only increased in the low burden group definition 1. None of the defined low burden groups showed signs of atrophy or glucose hypometabolism. Instead, we found slight increases in cortical thickness and metabolism in definition 2. Conclusions: There are biologically meaningful A beta-downstream effects in individuals with a low burden of A beta pathology, while structural and functional changes are still subtle or absent. These findings support considering individuals with a low burden of A beta pathology for clinical trials.
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20.
  • Salvado, G., et al. (författare)
  • Brain alterations in the early Alzheimer's continuum with amyloid-beta, tau, glial and neurodegeneration CSF markers
  • 2022
  • Ingår i: Brain Communications. - : Oxford University Press (OUP). - 2632-1297. ; 4:3
  • Tidskriftsartikel (refereegranskat)abstract
    • Higher grey matter volumes/cortical thickness and fluorodeoxyglucose uptake have been consistently found in cognitively unimpaired individuals with abnormal Alzheimer's disease biomarkers compared with those with normal biomarkers. It has been hypothesized that such transient increases may be associated with neuroinflammatory mechanisms triggered in response to early Alzheimer's pathology. Here, we evaluated, in the earliest stages of the Alzheimer's continuum, associations between grey matter volume and fluorodeoxyglucose uptake with CSF biomarkers of several pathophysiological mechanisms known to be altered in preclinical Alzheimer's disease stages. We included 319 cognitively unimpaired participants from the ALFA+ cohort with available structural MRI, fluorodeoxyglucose PET and CSF biomarkers of amyloid-beta and tau pathology (phosphorylated tau and total tau), synaptic dysfunction (neurogranin), neuronal and axonal injury (neurofilament light), glial activation (soluble triggering receptor on myeloid cells 2, YKL40, GFAP, interleukin-6 and S100b) and alpha-synuclein using the Roche NeuroToolKit. We first used the amyloid-beta/tau framework to investigate differences in the neuroimaging biomarkers between preclinical Alzheimer's disease stages. Then, we looked for associations between the neuroimaging markers and all the CSF markers. Given the non-negative nature of the concentrations of CSF biomarkers and their high collinearity, we clustered them using non-negative matrix factorization approach (components) and sought associations with the imaging markers. By groups, higher grey matter volumes were found in the amyloid-beta-positive tau-negative participants with respect to the reference amyloid-beta-negative tau-negative group. Both amyloid-beta and tau-positive participants showed higher fluorodeoxyglucose uptake than tau-negative individuals. Using the obtained components, we observed that tau pathology accompanied by YKL-40 (astrocytic marker) was associated with higher grey matter volumes and fluorodeoxyglucose uptake in extensive brain areas. Higher grey matter volumes in key Alzheimer-related regions were also found in association with two other components characterized by a higher expression of amyloid-beta in combination with different glial markers: one with higher GFAP and S100b levels (astrocytic markers) and the other one with interleukin-6 (pro-inflammatory). Notably, these components' expression had different behaviours across amyloid-beta/tau stages. Taken together, our results show that CSF amyloid-beta and phosphorylated tau, in combination with different aspects of glial response, have distinctive associations with higher grey matter volumes and increased glucose metabolism in key Alzheimer-related regions. These mechanisms combine to produce transient higher grey matter volumes and fluorodeoxyglucose uptake at the earliest stages of the Alzheimer's continuum, which may revert later on the course of the disease when neurodegeneration drives structural and metabolic cerebral changes. Salvado et al. show that amyloid-beta and tau pathologies, in combination with different aspects of glial response, have distinctive associations with brain's structure and function in key Alzheimer-related regions. These mechanisms combine to produce transient higher grey matter volumes and glucose metabolism at the earliest stages of the Alzheimer's continuum.
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21.
  • Salvado, G., et al. (författare)
  • Reactive astrogliosis is associated with higher cerebral glucose consumption in the early Alzheimer's continuum
  • 2022
  • Ingår i: European Journal of Nuclear Medicine and Molecular Imaging. - : Springer Science and Business Media LLC. - 1619-7070 .- 1619-7089. ; 49, s. 4567-4579
  • Tidskriftsartikel (refereegranskat)abstract
    • Purpose Glial activation is one of the earliest mechanisms to be altered in Alzheimer's disease (AD). Glial fibrillary acidic protein (GFAP) relates to reactive astrogliosis and can be measured in both cerebrospinal fluid (CSF) and blood. Plasma GFAP has been suggested to become altered earlier in AD than its CSF counterpart. Although astrocytes consume approximately half of the glucose-derived energy in the brain, the relationship between reactive astrogliosis and cerebral glucose metabolism is poorly understood. Here, we aimed to investigate the association between fluorodeoxyglucose ([F-18]FDG) uptake and reactive astrogliosis, by means of GFAP quantified in both plasma and CSF for the same participants. Methods We included 314 cognitively unimpaired participants from the ALFA + cohort, 112 of whom were amyloid-beta (A beta) positive. Associations between GFAP markers and [F-18]FDG uptake were studied. We also investigated whether these associations were modified by A beta and tau status (AT stages). Results Plasma GFAP was positively associated with glucose consumption in the whole brain, while CSF GFAP associations with [F-18]FDG uptake were only observed in specific smaller areas like temporal pole and superior temporal lobe. These associations persisted when accounting for biomarkers of A beta pathology but became negative in A beta-positive and tau-positive participants (A + T +) in similar areas of AD-related hypometabolism. Conclusions Higher astrocytic reactivity, probably in response to early AD pathological changes, is related to higher glucose consumption. With the onset of tau pathology, the observed uncoupling between astrocytic biomarkers and glucose consumption might be indicative of a failure to sustain the higher energetic demands required by reactive astrocytes.
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22.
  • Stankeviciute, L., et al. (författare)
  • Differential effects of sleep on brain structure and metabolism at the preclinical stages of AD
  • 2023
  • Ingår i: Alzheimers & Dementia. - 1552-5260. ; 19:12, s. 5371-5386
  • Tidskriftsartikel (refereegranskat)abstract
    • INTRODUCTIONPoor sleep quality is associated with cognitive outcomes in Alzheimer's disease (AD). We analyzed the associations between self-reported sleep quality and brain structure and function in cognitively unimpaired (CU) individuals. METHODSCU adults (N = 339) underwent structural magnetic resonance imaging, lumbar puncture, and the Pittsburgh Sleep Quality Index (PSQI) questionnaire. A subset (N = 295) performed [18F] fluorodeoxyglucose positron emission tomography scans. Voxel-wise associations with gray matter volumes (GMv) and cerebral glucose metabolism (CMRGlu) were performed including interactions with cerebrospinal fluid (CSF) AD biomarkers status. RESULTSPoorer sleep quality was associated with lower GMv and CMRGlu in the orbitofrontal and cingulate cortices independently of AD pathology. Self-reported sleep quality interacted with altered core AD CSF biomarkers in brain areas known to be affected in preclinical AD stages. DISCUSSIONPoor sleep quality may impact brain structure and function independently from AD pathology. Alternatively, AD-related neurodegeneration in areas involved in sleep-wake regulation may induce or worsen sleep disturbances.Poor sleep impacts brain structure and function independent of Alzheimer's disease (AD) pathology.Poor sleep exacerbates brain changes observed in preclinical AD.Sleep is an appealing therapeutic strategy for preventing AD. Highlights
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23.
  • Vilor-Tejedor, N., et al. (författare)
  • Perivascular spaces are associated with tau pathophysiology and synaptic dysfunction in early Alzheimer's continuum
  • 2021
  • Ingår i: Alzheimer's Research & Therapy. - : Springer Science and Business Media LLC. - 1758-9193. ; 13:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Background Perivascular spaces (PVS) have an important role in the elimination of metabolic waste from the brain. It has been hypothesized that the enlargement of PVS (ePVS) could be affected by pathophysiological mechanisms involved in Alzheimer's disease (AD), such as abnormal levels of CSF biomarkers. However, the relationship between ePVS and these pathophysiological mechanisms remains unknown. Objective We aimed to investigate the association between ePVS and CSF biomarkers of several pathophysiological mechanisms for AD. We hypothesized that ePVS will be associated to CSF biomarkers early in the AD continuum (i.e., amyloid positive cognitively unimpaired individuals). Besides, we explored associations between ePVS and demographic and cardiovascular risk factors. Methods The study included 322 middle-aged cognitively unimpaired participants from the ALFA + study, many within the Alzheimer's continuum. NeuroToolKit and Elecsys (R) immunoassays were used to measure CSF A beta 42, A beta 40, p-tau and t-tau, NfL, neurogranin, TREM2, YKL40, GFAP, IL6, S100, and alpha-synuclein. PVS in the basal ganglia (BG) and centrum semiovale (CS) were assessed based on a validated 4-point visual rating scale. Odds ratios were calculated for associations of cardiovascular and AD risk factors with ePVS using logistic and multinomial models adjusted for relevant confounders. Models were stratified by A beta status (positivity defined as A beta 42/40 < 0.071). Results The degree of PVS significantly increased with age in both, BG and CS regions independently of cardiovascular risk factors. Higher levels of p-tau, t-tau, and neurogranin were significantly associated with ePVS in the CS of A beta positive individuals, after accounting for relevant confounders. No associations were detected in the BG neither in A beta negative participants. Conclusions Our results support that ePVS in the CS are specifically associated with tau pathophysiology, neurodegeneration, and synaptic dysfunction in asymptomatic stages of the Alzheimer's continuum.
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26.
  • Cacciaglia, R., et al. (författare)
  • Age, sex and APOE-epsilon 4 modify the balance between soluble and fibrillar beta-amyloid in non-demented individuals: topographical patterns across two independent cohorts
  • 2022
  • Ingår i: Molecular Psychiatry. - : Springer Science and Business Media LLC. - 1359-4184 .- 1476-5578. ; 27, s. 2010-2018
  • Tidskriftsartikel (refereegranskat)abstract
    • Amyloid (A beta) pathology is the earliest detectable pathophysiological event along the Alzheimer's continuum, which can be measured both in the cerebrospinal fluid (CSF) and by Positron Emission Tomography (PET). Yet, these biomarkers identify two distinct A beta pools, reflecting the clearance of soluble A beta as opposed to the presence of A beta fibrils in the brain. An open question is whether risk factors known to increase Alzheimer's' disease (AD) prevalence may promote an imbalance between soluble and deposited A beta. Unveiling such interactions shall aid our understanding of the biological pathways underlying A beta deposition and foster the design of effective prevention strategies. We assessed the impact of three major AD risk factors, such as age, APOE-epsilon 4 and female sex, on the association between CSF and PET A beta, in two independent samples of non-demented individuals (ALFA: n = 320, ADNI: n = 682). We tested our hypotheses both in candidate regions of interest and in the whole brain using voxel-wise non-parametric permutations. All of the assessed risk factors induced a higher A beta deposition for any given level of CSF A beta 42/40, although in distinct cerebral topologies. While age and sex mapped onto neocortical areas, the effect of APOE-epsilon 4 was prominent in the medial temporal lobe, which represents a target of early tau deposition. Further, we found that the effects of age and APOE-epsilon 4 was stronger in women than in men. Our data indicate that specific AD risk factors affect the spatial patterns of cerebral A beta aggregation, with APOE-epsilon 4 possibly facilitating a co-localization between A beta and tau along the disease continuum.
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28.
  • Cacciaglia, R, et al. (författare)
  • Age, sex and APOE-ε4 modify the balance between soluble and fibrillar β-amyloid in non-demented individuals: topographical patterns across two independent cohorts
  • 2022
  • Ingår i: Molecular psychiatry. - : Springer Science and Business Media LLC. - 1476-5578 .- 1359-4184. ; 27:4, s. 2010-2018
  • Tidskriftsartikel (refereegranskat)abstract
    • Amyloid (Aβ) pathology is the earliest detectable pathophysiological event along the Alzheimer’s continuum, which can be measured both in the cerebrospinal fluid (CSF) and by Positron Emission Tomography (PET). Yet, these biomarkers identify two distinct Aβ pools, reflecting the clearance of soluble Aβ as opposed to the presence of Aβ fibrils in the brain. An open question is whether risk factors known to increase Alzheimer’s’ disease (AD) prevalence may promote an imbalance between soluble and deposited Aβ. Unveiling such interactions shall aid our understanding of the biological pathways underlying Aβ deposition and foster the design of effective prevention strategies. We assessed the impact of three major AD risk factors, such as age, APOE-ε4 and female sex, on the association between CSF and PET Aβ, in two independent samples of non-demented individuals (ALFA: n = 320, ADNI: n = 682). We tested our hypotheses both in candidate regions of interest and in the whole brain using voxel-wise non-parametric permutations. All of the assessed risk factors induced a higher Aβ deposition for any given level of CSF Aβ42/40, although in distinct cerebral topologies. While age and sex mapped onto neocortical areas, the effect of APOE-ε4 was prominent in the medial temporal lobe, which represents a target of early tau deposition. Further, we found that the effects of age and APOE-ε4 was stronger in women than in men. Our data indicate that specific AD risk factors affect the spatial patterns of cerebral Aβ aggregation, with APOE-ε4 possibly facilitating a co-localization between Aβ and tau along the disease continuum.
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29.
  • Cacciaglia, R., et al. (författare)
  • Genotypic effects of APOE-epsilon 4 on resting-state connectivity in cognitively intact individuals support functional brain compensation
  • 2022
  • Ingår i: Cerebral Cortex. - : Oxford University Press (OUP). - 1047-3211 .- 1460-2199. ; 33:6, s. 2748-60
  • Tidskriftsartikel (refereegranskat)abstract
    • The investigation of resting-state functional connectivity (rsFC) in asymptomatic individuals at genetic risk for Alzheimer's disease (AD) enables discovering the earliest brain alterations in preclinical stages of the disease. The APOE-epsilon 4 variant is the major genetic risk factor for AD, and previous studies have reported rsFC abnormalities in carriers of the epsilon 4 allele. Yet, no study has assessed APOE-epsilon 4 gene-dose effects on rsFC measures, and only a few studies included measures of cognitive performance to aid a clinical interpretation. We assessed the impact of APOE-epsilon 4 on rsFC in a sample of 429 cognitively unimpaired individuals hosting a high number of epsilon 4 homozygotes (n = 58), which enabled testing different models of genetic penetrance. We used independent component analysis and found a reduced rsFC as a function of the APOE-epsilon 4 allelic load in the temporal default-mode and the medial temporal networks, while recessive effects were found in the extrastriate and limbic networks. Some of these results were replicated in a subsample with negative amyloid markers. Interaction with cognitive data suggests that such a network reorganization may support cognitive performance in the epsilon 4-homozygotes. Our data indicate that APOE-epsilon 4 shapes the functional architecture of the resting brain and favor the idea of a network-based functional compensation.
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30.
  • Davies, Neil, et al. (författare)
  • Discussion on ‘Tectonic and environmental controls on Palaeozoic fluvial environments: reassessing the impacts of early land plants on sedimentation’
  • 2017
  • Ingår i: Journal of the Geological Society. - : Geological Society of London. - 0016-7649 .- 2041-479X. ; 174, s. 947-950
  • Tidskriftsartikel (refereegranskat)abstract
    • The first-order importance of tectonic and environmental controlsfor terrigenous sediment supply has rarely been questioned, but the role of vegetation in the modification of ancient alluvial signatures has been observed since the mid-20th century (Vogt 1941). Studies of sparsely vegetated rivers (Schumm 1968) and alluvial stratigraphic variation (Cotter 1978; Davies & Gibling 2010) led to observations of (1) plant modulation of alluvial signatures and (2) Palaeozoic facies shifts (PFS): unidirectional changes to facies diversity and frequency, in stratigraphic alliance with the plant fossil record. One PFS is the Siluro-Devonian appearance of mud rich, architecturally complex alluvium, traditionally ascribed to meandering rivers, and sedimentologically distinct from pre vegetation strata (Davies & Gibling 2010; Long 2011). Using selected secondary data, Santos et al. (2017) dispute the correlation of these observations using three key points, as follows. (1) The mid-Palaeozoic was typified by orogenic assembly of low-gradient equatorial continents and elevated sea level, which led to tropical weathering (abundant fine sediment) and extensive alluvial plains. This drove the PFS by promoting river meandering independently of vegetation. (2) Meandering does not require vegetation; this is shown by examples in Precambrian deposits, on other planets, and in ‘non-vegetated’ deserts. Meandering rivers were more abundant than the pre vegetation rock record suggests, owing to selective bypass and deflation of fine material. (3) Early Siluro-Devonian (meaning Ludlow–Early Devonian) land plants were too small, their biomass and cover too limited, and their wetland habitat too narrow to have stabilized meandering channels, influencing landscape little more than earlier microbial communities. We contest the conclusions and method of the paper, and deal with each point in turn.
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31.
  • Duquesne, Amílcar, et al. (författare)
  • Diagnostic Testing Accuracy for Helicobacter pylori Infection among Adult Patients with Dyspepsia in Cuba’s Primary Care Setting
  • 2023
  • Ingår i: Microorganisms. - 2076-2607. ; 11:4
  • Tidskriftsartikel (refereegranskat)abstract
    • Evidence of the effectiveness of the tests used to diagnose Helicobacter pylori (H. pylori) in primary healthcare is limited. This cross-sectional study aims to assess the accuracy of tests used for to diagnose H. pylori infection in primary care patients and its relationship with gastroduodenal pathologies. Over 12 months, 173 primary care patients with dyspeptic symptoms were referred for upper gastrointestinal endoscopy to obtain gastric biopsies, and venous blood was extracted from them. H. pylori infection was detected using a rapid urease test (RUT), real-time polymerase chain reaction (RT-PCR), H. pylori-IgG ELISA, and Western blot (WB). The culture and histological findings were used as the reference standard for H. pylori infection. H. pylori prevalence was 50%. There were no significant differences between men and women overall or by age group. The presence of H. pylori was associated with chronic moderate gastritis and its absence with chronic inactive gastritis, as well as the combination of gastritis and gastric lesions (p < 0.05). RUT and ELISA H. pylori -IgG tests showed the highest overall performance (accuracy 98.9% and 84.4%), followed by WB and RT-PCR (accuracy 79.3% and 73.9%). These findings support the notion that combined invasive and noninvasive methods, such as RUT and H. pylori-IgG ELISA, can be a primary diagnostic screening tool for detecting H. pylori among adult dyspeptic patients in Cuba’s primary care setting.
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32.
  • Falcon, Luisa I, et al. (författare)
  • Ultrastructure of unicellular N-2 fixing cyanobacteria from the tropical North Atlantic and subtropical North Pacific Oceans
  • 2004
  • Ingår i: Journal of Phycology. ; 40:6, s. 1074-1078
  • Tidskriftsartikel (refereegranskat)abstract
    • Abstract: Nitrogen fixing unicellular marine cyanobacteria may have a major role in the global biogeochemistry of N; nevertheless, little is known about their phylogeny and morphology. We isolated N-2 fixing unicellular cyanobacteria from the tropical North Atlantic and subtropical North Pacific Oceans and examined ultrastructural dynamics during dark:light cycles when grown in incubators. The isolate from the subtropical North Pacific was larger and showed a size variation from 3 to 7 mum but had similar morphology and cell division-plane characteristics as the isolate from the North Atlantic (2.5 mum). Nitrogen fixation only occurred during the dark phase, and ultrastructural analysis demonstrated changes in the appearance and quantity of large carbohydrate-like granules present in the cells. To verify the composition of these carbohydrate-like granules, staining with periodic acid, thioacetic acid, and silver was carried out, and a positive reaction was obvious in all cells. The cells from the Atlantic seemed to empty their polysaccharide granules during the night, whereas those from the Pacific showed a decrease in the number of their granules. Our work suggests that phylogenetically related strains of unicellular N-2 fixing cyanobacteria from different oceans showed similar carbohydrate-like granules that could be used to fuel N-2 fixation during darkness.
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33.
  • Kalra, Hina, et al. (författare)
  • Vesiclepedia : a compendium for extracellular vesicles with continuous community annotation
  • 2012
  • Ingår i: PLoS biology. - : Public library of science. - 1544-9173 .- 1545-7885. ; 10:12, s. e1001450-
  • Tidskriftsartikel (refereegranskat)abstract
    • Extracellular vesicles (EVs) are membraneous vesicles released by a variety of cells into their microenvironment. Recent studies have elucidated the role of EVs in intercellular communication, pathogenesis, drug, vaccine and gene-vector delivery, and as possible reservoirs of biomarkers. These findings have generated immense interest, along with an exponential increase in molecular data pertaining to EVs. Here, we describe Vesiclepedia, a manually curated compendium of molecular data (lipid, RNA, and protein) identified in different classes of EVs from more than 300 independent studies published over the past several years. Even though databases are indispensable resources for the scientific community, recent studies have shown that more than 50% of the databases are not regularly updated. In addition, more than 20% of the database links are inactive. To prevent such database and link decay, we have initiated a continuous community annotation project with the active involvement of EV researchers. The EV research community can set a gold standard in data sharing with Vesiclepedia, which could evolve as a primary resource for the field.
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34.
  • Lener, Thomas, et al. (författare)
  • Applying extracellular vesicles based therapeutics in clinical trials - an ISEV position paper.
  • 2015
  • Ingår i: Journal of extracellular vesicles. - : Wiley. - 2001-3078. ; 4
  • Tidskriftsartikel (refereegranskat)abstract
    • Extracellular vesicles (EVs), such as exosomes and microvesicles, are released by different cell types and participate in physiological and pathophysiological processes. EVs mediate intercellular communication as cell-derived extracellular signalling organelles that transmit specific information from their cell of origin to their target cells. As a result of these properties, EVs of defined cell types may serve as novel tools for various therapeutic approaches, including (a) anti-tumour therapy, (b) pathogen vaccination, (c) immune-modulatory and regenerative therapies and (d) drug delivery. The translation of EVs into clinical therapies requires the categorization of EV-based therapeutics in compliance with existing regulatory frameworks. As the classification defines subsequent requirements for manufacturing, quality control and clinical investigation, it is of major importance to define whether EVs are considered the active drug components or primarily serve as drug delivery vehicles. For an effective and particularly safe translation of EV-based therapies into clinical practice, a high level of cooperation between researchers, clinicians and competent authorities is essential. In this position statement, basic and clinical scientists, as members of the International Society for Extracellular Vesicles (ISEV) and of the European Cooperation in Science and Technology (COST) program of the European Union, namely European Network on Microvesicles and Exosomes in Health and Disease (ME-HaD), summarize recent developments and the current knowledge of EV-based therapies. Aspects of safety and regulatory requirements that must be considered for pharmaceutical manufacturing and clinical application are highlighted. Production and quality control processes are discussed. Strategies to promote the therapeutic application of EVs in future clinical studies are addressed.
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35.
  • Lucien, Fabrice, et al. (författare)
  • MIBlood-EV: Minimal information to enhance the quality and reproducibility of blood extracellular vesicle research
  • 2023
  • Ingår i: Journal of Extracellular Vesicles. - 2001-3078. ; 12:12
  • Tidskriftsartikel (refereegranskat)abstract
    • Blood is the most commonly used body fluid for extracellular vesicle (EV) research. The composition of a blood sample and its derivatives (i.e., plasma and serum) are not only donor-dependent but also influenced by collection and preparation protocols. Since there are hundreds of pre-analytical protocols and over forty variables, the development of standard operating procedures for EV research is very challenging. To improve the reproducibility of blood EV research, the International Society for Extracellular Vesicles (ISEV) Blood EV Task Force proposes standardized reporting of (i) the applied blood collection and preparation protocol and (ii) the quality of the prepared plasma and serum samples. Gathering detailed information will provide insight into the performance of the protocols and more effectively identify potential confounders in the prepared plasma and serum samples. To collect this information, the ISEV Blood EV Task Force created the Minimal Information for Blood EV research (MIBlood-EV), a tool to record and report information about pre-analytical protocols used for plasma and serum preparation as well as assays used to assess the quality of these preparations. This tool does not require modifications of established local pre-analytical protocols and can be easily implemented to enhance existing databases thereby enabling evidence-based optimization of pre-analytical protocols through meta-analysis. Taken together, insight into the quality of prepared plasma and serum samples will (i) improve the quality of biobanks for EV research, (ii) guide the exchange of plasma and serum samples between biobanks and laboratories, (iii) facilitate inter-laboratory comparative EV studies, and (iv) improve the peer review process.
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36.
  • Vano-Galvan, S., et al. (författare)
  • Alopecia areata totalis and universalis: a multicenter review of 132 patients in Spain
  • 2017
  • Ingår i: Journal of the European Academy of Dermatology and Venereology. - : Wiley. - 0926-9959. ; 31:3, s. 550-556
  • Tidskriftsartikel (refereegranskat)abstract
    • BackgroundAlopecia areata totalis (AAT) and universalis (AAU) pose a therapeutic challenge. ObjectiveTo describe the clinical and epidemiological features, therapeutic response and prognostic factors in a large series of patients diagnosed with AAT and AAU. MethodsThis retrospective multicenter study included patients diagnosed with AAT/AAU with a minimum follow-up of 12 months. Response was assessed based on the regrowth of scalp hair. ResultsIn all, 132 patients (92 women and 40 men) - 80 (61%) diagnosed with AAU and 52 (39%) diagnosed with AAT - were included. The median time between the presentation of alopecia areata (AA) and the development of extensive AA was 1 year and it was less than 4 years in 121 patients (91%). There was an initial response to treatment in 64% of patients, although only 14% presented a persistent response. Adverse side effects from the medications used were detected in 33% of patients. The prognostic factors associated with poor response were the presence of AAU and a positive family history of AA. ConclusionsTreatment of AAT and AAU is challenging. Although an initial regrowth may be achieved, the duration of response is usually short. There were no significant differences on the effectiveness or duration of response between the various systemic therapies.
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