1. |
- van de Vegte, Yordi, et al.
(författare)
-
Genetic insights into resting heart rate and its role in cardiovascular disease
- 2023
-
Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 14:1
-
Tidskriftsartikel (refereegranskat)abstract
- The genetics and clinical consequences of resting heart rate (RHR) remain incompletely understood. Here, the authors discover new genetic variants associated with RHR and find that higher genetically predicted RHR decreases risk of atrial fibrillation and ischemic stroke. Resting heart rate is associated with cardiovascular diseases and mortality in observational and Mendelian randomization studies. The aims of this study are to extend the number of resting heart rate associated genetic variants and to obtain further insights in resting heart rate biology and its clinical consequences. A genome-wide meta-analysis of 100 studies in up to 835,465 individuals reveals 493 independent genetic variants in 352 loci, including 68 genetic variants outside previously identified resting heart rate associated loci. We prioritize 670 genes and in silico annotations point to their enrichment in cardiomyocytes and provide insights in their ECG signature. Two-sample Mendelian randomization analyses indicate that higher genetically predicted resting heart rate increases risk of dilated cardiomyopathy, but decreases risk of developing atrial fibrillation, ischemic stroke, and cardio-embolic stroke. We do not find evidence for a linear or non-linear genetic association between resting heart rate and all-cause mortality in contrast to our previous Mendelian randomization study. Systematic alteration of key differences between the current and previous Mendelian randomization study indicates that the most likely cause of the discrepancy between these studies arises from false positive findings in previous one-sample MR analyses caused by weak-instrument bias at lower P-value thresholds. The results extend our understanding of resting heart rate biology and give additional insights in its role in cardiovascular disease development.
|
|
2. |
- Beal, Jacob, et al.
(författare)
-
Robust estimation of bacterial cell count from optical density
- 2020
-
Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
-
Tidskriftsartikel (refereegranskat)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
|
|
3. |
- Kehoe, Laura, et al.
(författare)
-
Make EU trade with Brazil sustainable
- 2019
-
Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 364:6438, s. 341-
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
|
|
4. |
- Kattge, Jens, et al.
(författare)
-
TRY plant trait database - enhanced coverage and open access
- 2020
-
Ingår i: Global Change Biology. - : Wiley-Blackwell. - 1354-1013 .- 1365-2486. ; 26:1, s. 119-188
-
Tidskriftsartikel (refereegranskat)abstract
- Plant traits-the morphological, anatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives.
|
|
5. |
- Ademuyiwa, Adesoji O., et al.
(författare)
-
Determinants of morbidity and mortality following emergency abdominal surgery in children in low-income and middle-income countries
- 2016
-
Ingår i: BMJ Global Health. - : BMJ Publishing Group Ltd. - 2059-7908. ; 1:4
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Child health is a key priority on the global health agenda, yet the provision of essential and emergency surgery in children is patchy in resource-poor regions. This study was aimed to determine the mortality risk for emergency abdominal paediatric surgery in low-income countries globally.Methods: Multicentre, international, prospective, cohort study. Self-selected surgical units performing emergency abdominal surgery submitted prespecified data for consecutive children aged <16 years during a 2-week period between July and December 2014. The United Nation's Human Development Index (HDI) was used to stratify countries. The main outcome measure was 30-day postoperative mortality, analysed by multilevel logistic regression.Results: This study included 1409 patients from 253 centres in 43 countries; 282 children were under 2 years of age. Among them, 265 (18.8%) were from low-HDI, 450 (31.9%) from middle-HDI and 694 (49.3%) from high-HDI countries. The most common operations performed were appendectomy, small bowel resection, pyloromyotomy and correction of intussusception. After adjustment for patient and hospital risk factors, child mortality at 30 days was significantly higher in low-HDI (adjusted OR 7.14 (95% CI 2.52 to 20.23), p<0.001) and middle-HDI (4.42 (1.44 to 13.56), p=0.009) countries compared with high-HDI countries, translating to 40 excess deaths per 1000 procedures performed.Conclusions: Adjusted mortality in children following emergency abdominal surgery may be as high as 7 times greater in low-HDI and middle-HDI countries compared with high-HDI countries. Effective provision of emergency essential surgery should be a key priority for global child health agendas.
|
|
6. |
- Jin, Shoko, et al.
(författare)
-
The wide-field, multiplexed, spectroscopic facility WEAVE : Survey design, overview, and simulated implementation
- 2024
-
Ingår i: Monthly notices of the Royal Astronomical Society. - : Oxford University Press. - 0035-8711 .- 1365-2966. ; 530:3, s. 2688-2730
-
Tidskriftsartikel (refereegranskat)abstract
- WEAVE, the new wide-field, massively multiplexed spectroscopic survey facility for the William Herschel Telescope, saw first light in late 2022. WEAVE comprises a new 2-deg field-of-view prime-focus corrector system, a nearly 1000-multiplex fibre positioner, 20 individually deployable 'mini' integral field units (IFUs), and a single large IFU. These fibre systems feed a dual-beam spectrograph covering the wavelength range 366-959nm at R similar to 5000, or two shorter ranges at . After summarizing the design and implementation of WEAVE and its data systems, we present the organization, science drivers, and design of a five- to seven-year programme of eight individual surveys to: (i) study our Galaxy's origins by completing Gaia's phase-space information, providing metallicities to its limiting magnitude for similar to 3 million stars and detailed abundances for similar to 1.5 million brighter field and open-cluster stars; (ii) survey similar to 0.4 million Galactic-plane OBA stars, young stellar objects, and nearby gas to understand the evolution of young stars and their environments; (iii) perform an extensive spectral survey of white dwarfs; (iv) survey similar to 400 neutral-hydrogen-selected galaxies with the IFUs; (v) study properties and kinematics of stellar populations and ionized gas in z < 0.5 cluster galaxies; (vi) survey stellar populations and kinematics in field galaxies at 0.3 less than or similar to z less than or similar to 0.7; (vii) study the cosmic evolution of accretion and star formation using >1 million spectra of LOFAR-selected radio sources; and (viii) trace structures using intergalactic/circumgalactic gas at z > 2. Finally, we describe the WEAVE Operational Rehearsals using the WEAVE Simulator.
|
|
7. |
- Kovacs, Gabor G., et al.
(författare)
-
Multisite Assessment of Aging-Related Tau Astrogliopathy (ARTAG)
- 2017
-
Ingår i: Journal of Neuropathology and Experimental Neurology. - : Oxford University Press (OUP). - 0022-3069 .- 1554-6578. ; 76:7, s. 605-619
-
Tidskriftsartikel (refereegranskat)abstract
- Aging-related tau astrogliopathy (ARTAG) is a recently introduced terminology. To facilitate the consistent identification of ARTAG and to distinguish it from astroglial tau pathologies observed in the primary frontotemporal lobar degeneration tauopathies we evaluated how consistently neuropathologists recognize (1) different astroglial tau immunoreactivities, including those of ARTAG and those associated with primary tauopathies (Study 1); (2) ARTAG types (Study 2A); and (3) ARTAG severity (Study 2B). Microphotographs and scanned sections immunostained for phosphorylated tau (AT8) were made available for download and preview. Percentage of agreement and kappa values with 95% confidence interval (CI) were calculated for each evaluation. The overall agreement for Study 1 was > 60% with a kappa value of 0.55 (95% CI 0.433-0.645). Moderate agreement (> 90%, kappa 0.48, 95% CI 0.457-0.900) was reached in Study 2A for the identification of ARTAG pathology for each ARTAG subtype (kappa 0.37-0.72), whereas fair agreement (kappa 0.40, 95% CI 0.341-0.445) was reached for the evaluation of ARTAG severity. The overall assessment of ARTAG showed moderate agreement (kappa 0.60, 95% CI 0.534-0.653) among raters. Our study supports the application of the current harmonized evaluation strategy for ARTAG with a slight modification of the evaluation of its severity.
|
|
8. |
- Martin Ginis, Kathleen A., et al.
(författare)
-
Evidence-based scientific exercise guidelines for adults with spinal cord injury : an update and a new guideline
- 2018
-
Ingår i: Spinal Cord. - : Springer Science and Business Media LLC. - 1362-4393 .- 1476-5624. ; 56, s. 308-321
-
Tidskriftsartikel (refereegranskat)abstract
- Objectives: To describe the process and outcomes of using a new evidence base to develop scientific guidelines that specify the type and minimum dose of exercise necessary to improve fitness and cardiometabolic health in adults with spinal cord injury (SCI). Setting: International. Methods: Using Appraisal of Guidelines, Research and Evaluation (AGREE) II reporting criteria, steps included (a) determining the guidelines’ scope; (b) conducting a systematic review of relevant literature; (c) holding three consensus panel meetings (European, Canadian and International) to formulate the guidelines; (d) obtaining stakeholder feedback; and (e) process evaluation by an AGREE II consultant. Stakeholders were actively involved in steps (c) and (d). Results: For cardiorespiratory fitness and muscle strength benefits, adults with a SCI should engage in at least 20 min of moderate to vigorous intensity aerobic exercise 2 times per week AND 3 sets of strength exercises for each major functioning muscle group, at a moderate to vigorous intensity, 2 times per week (strong recommendation). For cardiometabolic health benefits, adults with a SCI are suggested to engage in at least 30 min of moderate to vigorous intensity aerobic exercise 3 times per week (conditional recommendation). Conclusions: Through a systematic, rigorous, and participatory process involving international scientists and stakeholders, a new exercise guideline was formulated for cardiometabolic health benefits. A previously published SCI guideline was endorsed for achieving fitness benefits. These guidelines represent an important step toward international harmonization of exercise guidelines for adults with SCI, and a foundation for developing exercise policies and programs for people with SCI around the world.
|
|
9. |
|
|
10. |
- Stanaway, Jeffrey D., et al.
(författare)
-
Global, regional, and national comparative risk assessment of 84 behavioural, environmental and occupational, and metabolic risks or clusters of risks for 195 countries and territories, 1990-2017: A systematic analysis for the Global Burden of Disease Study 2017
- 2018
-
Ingår i: The Lancet. - 1474-547X .- 0140-6736. ; 392:10159, s. 1923-1994
-
Tidskriftsartikel (refereegranskat)abstract
- Background The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2017 comparative risk assessment (CRA) is a comprehensive approach to risk factor quantification that offers a useful tool for synthesising evidence on risks and risk-outcome associations. With each annual GBD study, we update the GBD CRA to incorporate improved methods, new risks and risk-outcome pairs, and new data on risk exposure levels and risk- outcome associations. Methods We used the CRA framework developed for previous iterations of GBD to estimate levels and trends in exposure, attributable deaths, and attributable disability-adjusted life-years (DALYs), by age group, sex, year, and location for 84 behavioural, environmental and occupational, and metabolic risks or groups of risks from 1990 to 2017. This study included 476 risk-outcome pairs that met the GBD study criteria for convincing or probable evidence of causation. We extracted relative risk and exposure estimates from 46 749 randomised controlled trials, cohort studies, household surveys, census data, satellite data, and other sources. We used statistical models to pool data, adjust for bias, and incorporate covariates. Using the counterfactual scenario of theoretical minimum risk exposure level (TMREL), we estimated the portion of deaths and DALYs that could be attributed to a given risk. We explored the relationship between development and risk exposure by modelling the relationship between the Socio-demographic Index (SDI) and risk-weighted exposure prevalence and estimated expected levels of exposure and risk-attributable burden by SDI. Finally, we explored temporal changes in risk-attributable DALYs by decomposing those changes into six main component drivers of change as follows: (1) population growth; (2) changes in population age structures; (3) changes in exposure to environmental and occupational risks; (4) changes in exposure to behavioural risks; (5) changes in exposure to metabolic risks; and (6) changes due to all other factors, approximated as the risk-deleted death and DALY rates, where the risk-deleted rate is the rate that would be observed had we reduced the exposure levels to the TMREL for all risk factors included in GBD 2017.
|
|
11. |
- Zuntini, Alexandre R., et al.
(författare)
-
Phylogenomics and the rise of the angiosperms
- 2024
-
Ingår i: NATURE. - 0028-0836 .- 1476-4687. ; 629, s. 843-850
-
Tidskriftsartikel (refereegranskat)abstract
- Angiosperms are the cornerstone of most terrestrial ecosystems and human livelihoods(1,2). A robust understanding of angiosperm evolution is required to explain their rise to ecological dominance. So far, the angiosperm tree of life has been determined primarily by means of analyses of the plastid genome(3,4). Many studies have drawn on this foundational work, such as classification and first insights into angiosperm diversification since their Mesozoic origins(5-7). However, the limited and biased sampling of both taxa and genomes undermines confidence in the tree and its implications. Here, we build the tree of life for almost 8,000 (about 60%) angiosperm genera using a standardized set of 353 nuclear genes(8). This 15-fold increase in genus-level sampling relative to comparable nuclear studies(9) provides a critical test of earlier results and brings notable change to key groups, especially in rosids, while substantiating many previously predicted relationships. Scaling this tree to time using 200 fossils, we discovered that early angiosperm evolution was characterized by high gene tree conflict and explosive diversification, giving rise to more than 80% of extant angiosperm orders. Steady diversification ensued through the remaining Mesozoic Era until rates resurged in the Cenozoic Era, concurrent with decreasing global temperatures and tightly linked with gene tree conflict. Taken together, our extensive sampling combined with advanced phylogenomic methods shows the deep history and full complexity in the evolution of a megadiverse clade.
|
|
12. |
- Adams, Charleen, et al.
(författare)
-
Circulating Metabolic Biomarkers of Screen-Detected Prostate Cancer in the ProtecT Study
- 2019
-
Ingår i: Cancer Epidemiology, Biomarkers and Prevention. - : American Association for Cancer Research (AACR). - 1055-9965 .- 1538-7755. ; 28:1, s. 208-216
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Whether associations between circulating metabolites and prostate cancer are causal is unknown. We report on the largest study of metabolites and prostate cancer (2,291 cases and 2,661 controls) and appraise causality for a subset of the prostate cancer-metabolite associations using two-sample Mendelian randomization (MR).MATERIALS AND METHODS: The case-control portion of the study was conducted in nine UK centres with men aged 50-69 years who underwent prostate-specific antigen (PSA) screening for prostate cancer within the Prostate testing for cancer and Treatment (ProtecT) trial. Two data sources were used to appraise causality: a genome-wide association study (GWAS) of metabolites in 24,925 participants and a GWAS of prostate cancer in 44,825 cases and 27,904 controls within the Association Group to Investigate Cancer Associated Alterations in the Genome (PRACTICAL) consortium.RESULTS: Thirty-five metabolites were strongly associated with prostate cancer (p <0.0014, multiple-testing threshold). These fell into four classes: i) lipids and lipoprotein subclass characteristics (total cholesterol and ratios, cholesterol esters and ratios, free cholesterol and ratios, phospholipids and ratios, and triglyceride ratios); ii) fatty acids and ratios; iii) amino acids; iv) and fluid balance. Fourteen top metabolites were proxied by genetic variables, but MR indicated these were not causal.CONCLUSIONS: We identified 35 circulating metabolites associated with prostate cancer presence, but found no evidence of causality for those 14 testable with MR. Thus, the 14 MR-tested metabolites are unlikely to be mechanistically important in prostate cancer risk.IMPACT: The metabolome provides a promising set of biomarkers that may aid prostate cancer classification.
|
|
13. |
- Anney, Richard, et al.
(författare)
-
Individual common variants exert weak effects on the risk for autism spectrum disorders.
- 2012
-
Ingår i: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 21:21, s. 4781-92
-
Tidskriftsartikel (refereegranskat)abstract
- While it is apparent that rare variation can play an important role in the genetic architecture of autism spectrum disorders (ASD), the contribution of common variation to ASD risk is less clear. To produce a more comprehensive picture, we report Stage 2 of the Autism Genome Project genome-wide association study, adding 1301 ASD families and bringing the total to 2705 families analysed (Stages 1 and 2). In addition to evaluating association of individual SNPs, we also sought evidence that common variants, en masse, might affect risk. Despite genotyping over a million SNPs covering the genome, no single SNP shows significant association with ASD or selected phenotypes at a genome-wide level. The SNP that achieves the smallest p-value from secondary analyses is rs1718101. It falls in CNTNAP2, a gene previously implicated in susceptibility for ASD. This SNP also shows modest association with age of word/phrase acquisition in ASD subjects, of interest because features of language development are also associated with other variation in CNTNAP2. By contrast, allele-scores derived from the transmission of common alleles to Stage 1 cases significantly predict case-status in the independent Stage 2 sample. Despite being significant, the variance explained by these allele scores was small (Vm< 1%). Based on results from individual SNPs and their en masse effect on risk, as inferred from the allele-score results, it is reasonable to conclude that common variants affect ASD risk but their individual effects are modest.
|
|
14. |
- Barker, Vanessa, 1971-, et al.
(författare)
-
This is Denmark : Prison Islands and the Detention of Immigrants
- 2021
-
Ingår i: British Journal of Criminology. - : Oxford University Press (OUP). - 0007-0955 .- 1464-3529. ; 61:6, s. 1540-1556
-
Tidskriftsartikel (refereegranskat)abstract
- According to mainstream criminology, Nordic societies with their generous welfare states are supposed to moderate, if not restrict, penal powers. In the case of migration, we see the opposite pattern. In Denmark, we see extended use of penal institutions and penal harms to contain and remove unwanted populations from the region, including proposals for a prison island and the confinement of migrants in 19th century prisons. To make sense of these developments and interpret its social meaning, we unpack the logic of the punishment–welfare nexus and Nordic exceptionalism. We find that Denmark expands penal power to regulate non-citizens, deter migration and uphold national interests. These repressive practices are not exceptions to the rule but rather illustrate the exclusionary edge and very nature of the penal regimes in Denmark, a Nordic welfare state.
|
|
15. |
- Bossini-Castillo, Lara, et al.
(författare)
-
A replication study confirms the association of TNFSF4 (OX40L) polymorphisms with systemic sclerosis in a large European cohort
- 2011
-
Ingår i: Annals of the Rheumatic Diseases. - : BMJ. - 1468-2060 .- 0003-4967. ; 70:4, s. 638-641
-
Tidskriftsartikel (refereegranskat)abstract
- Objectives The aim of this study was to confirm the influence of TNFSF4 polymorphisms on systemic sclerosis (SSc) susceptibility and phenotypic features. Methods A total of 8 European populations of Caucasian ancestry were included, comprising 3014 patients with SSc and 3125 healthy controls. Four genetic variants of TNFSF4 gene promoter (rs1234314, rs844644, rs844648 and rs12039904) were selected as genetic markers. Results A pooled analysis revealed the association of rs1234314 and rs12039904 polymorphisms with SSc (OR 1.15, 95% CI 1.02 to 1.31; OR 1.18, 95% CI 1.08 to 1.29, respectively). Significant association of the four tested variants with patients with limited cutaneous SSc (lcSSc) was revealed (rs1234314 OR 1.22, 95% CI 1.07 to 1.38; rs844644 OR 0.91, 95% CI 0.83 to 0.99; rs844648 OR 1.10, 95% CI 1.01 to 1.20 and rs12039904 OR 1.20, 95% CI 1.09 to 1.33). Association of rs1234314, rs844648 and rs12039904 minor alleles with patients positive for anti-centromere antibodies (ACA) remained significant (OR 1.23, 95% CI 1.10 to 1.37; OR 1.12, 95% CI 1.01 to 1.25; OR 1.22, 95% CI 1.07 to 1.38, respectively). Haplotype analysis confirmed a protective haplotype associated with SSc, lcSSc and ACA positive subgroups (OR 0.88, 95% CI 0.82 to 0.96; OR 0.88, 95% CI 0.80 to 0.96; OR 0.86, 95% CI 0.77 to 0.97, respectively) and revealed a new risk haplotype associated with the same groups of patients (OR 1.14, 95% CI 1.03 to 1.26; OR 1.20, 95% CI 1.08 to 1.35; OR 1.23, 95% CI 1.07 to 1.42, respectively). Conclusions The data confirm the influence of TNFSF4 polymorphisms in SSc genetic susceptibility, especially in subsets of patients positive for lcSSc and ACA.
|
|
16. |
- Bossini-Castillo, Lara, et al.
(författare)
-
Confirmation of association of the macrophage migration inhibitory factor gene with systemic sclerosis in a large European population.
- 2011
-
Ingår i: Rheumatology (Oxford, England). - : Oxford University Press (OUP). - 1462-0332 .- 1462-0324. ; 50, s. 1976-1981
-
Tidskriftsartikel (refereegranskat)abstract
- Objectives. The aim of this study was to confirm the implication of macrophage migration inhibitory factor (MIF) gene in SSc susceptibility or clinical phenotypes in a large European population.Methods. A total of 3800 SSc patients and 4282 healthy controls of white Caucasian ancestry from eight different European countries were included in the study. The MIF -173 single nucleotide polymorphism (SNP) was selected as genetic marker and genotyped using Taqman 5' allelic discrimination assay.Results. The MIF -173 SNP showed association with SSc [P = 0.04, odds ratio (OR) = 1.10, 95% CI 1.00, 1.19]. Analysis of the MIF -173 polymorphism according to SSc clinical phenotype revealed that the frequency of the -173*C allele was significantly higher in the dcSSc group compared with controls (P = 5.30E-03, OR = 1.21, 95% CI 1.07, 1.38). Conversely, the frequency of the MIF -173*C allele was significantly underrepresented in the lcSSc group compared with dcSSc patients, supporting previous findings [(P = 0.04, OR = 0.86, 95% CI 0.75, 0.99); meta-analysis including previous results (P = 0.005, OR = 0.83, 95% CI 0.73, 0.94)].Conclusion. Our results confirm the role of MIF -173 promoter polymorphism in SSc, and provide evidence of a strong association with the dcSSc subgroup of patients. Hence, the MIF -173 variant is confirmed as a promising clinical phenotype genetic marker.
|
|
17. |
- Callaghan, Terry, et al.
(författare)
-
Multi-Decadal Changes in Tundra Environments and Ecosystems : Synthesis of the International Polar Year-Back to the Future Project (IPY-BTF)
- 2011
-
Ingår i: Ambio. - : Springer Science and Business Media LLC. - 0044-7447 .- 1654-7209. ; 40:6, s. 705-716
-
Tidskriftsartikel (refereegranskat)abstract
- Understanding the responses of tundra systemsto global change has global implications. Most tundraregions lack sustained environmental monitoring and oneof the only ways to document multi-decadal change is toresample historic research sites. The International PolarYear (IPY) provided a unique opportunity for such researchthrough the Back to the Future (BTF) project (IPY project#512). This article synthesizes the results from 13 paperswithin this Ambio Special Issue. Abiotic changes includeglacial recession in the Altai Mountains, Russia; increasedsnow depth and hardness, permafrost warming, andincreased growing season length in sub-arctic Sweden;drying of ponds in Greenland; increased nutrient availabilityin Alaskan tundra ponds, and warming at mostlocations studied. Biotic changes ranged from relativelyminor plant community change at two sites in Greenland tomoderate change in the Yukon, and to dramatic increasesin shrub and tree density on Herschel Island, and in subarcticSweden. The population of geese tripled at one sitein northeast Greenland where biomass in non-grazed plotsdoubled. A model parameterized using results from a BTFstudy forecasts substantial declines in all snowbeds andincreases in shrub tundra on Niwot Ridge, Colorado overthe next century. In general, results support and provideimproved capacities for validating experimental manipulation,remote sensing, and modeling studies.
|
|
18. |
- Comas-Bru, Laia, et al.
(författare)
-
Evaluating model outputs using integrated global speleothem records of climate change since the last glacial
- 2019
-
Ingår i: Climate of the Past. - : Copernicus GmbH. - 1814-9324 .- 1814-9332. ; 15:4, s. 1557-1579
-
Tidskriftsartikel (refereegranskat)abstract
- Although quantitative isotope data from speleothems has been used to evaluate isotope-enabled model simulations, currently no consensus exists regarding the most appropriate methodology through which to achieve this. A number of modelling groups will be running isotope-enabled palaeoclimate simulations in the framework of the Coupled Model Intercomparison Project Phase 6, so it is timely to evaluate different approaches to using the speleothem data for data-model comparisons. Here, we illustrate this using 456 globally distributed speleothem delta O-18 records from an updated version of the Speleothem Isotopes Synthesis and Analysis (SISAL) database and palaeoclimate simulations generated using the ECHAM5-wiso isotope-enabled atmospheric circulation model. We show that the SISAL records reproduce the first-order spatial patterns of isotopic variability in the modern day, strongly supporting the application of this dataset for evaluating model-derived isotope variability into the past. However, the discontinuous nature of many speleothem records complicates the process of procuring large numbers of records if data-model comparisons are made using the traditional approach of comparing anomalies between a control period and a given palaeoclimate experiment. To circumvent this issue, we illustrate techniques through which the absolute isotope values during any time period could be used for model evaluation. Specifically, we show that speleothem isotope records allow an assessment of a model's ability to simulate spatial isotopic trends. Our analyses provide a protocol for using speleothem isotope data for model evaluation, including screening the observations to take into account the impact of speleothem mineralogy on delta O-18 values, the optimum period for the modern observational baseline and the selection of an appropriate time window for creating means of the isotope data for palaeo-time-slices.
|
|
19. |
- Corbin, Laura J., et al.
(författare)
-
Formalising recall by genotype as an efficient approach to detailed phenotyping and causal inference
- 2018
-
Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 9:1
-
Tidskriftsartikel (refereegranskat)abstract
- Detailed phenotyping is required to deepen our understanding of the biological mechanisms behind genetic associations. In addition, the impact of potentially modifiable risk factors on disease requires analytical frameworks that allow causal inference. Here, we discuss the characteristics of Recall-by-Genotype (RbG) as a study design aimed at addressing both these needs. We describe two broad scenarios for the application of RbG: studies using single variants and those using multiple variants. We consider the efficacy and practicality of the RbG approach, provide a catalogue of UK-based resources for such studies and present an online RbG study planner.
|
|
20. |
- Debette, Stephanie, et al.
(författare)
-
Identification of cis- and trans-Acting Genetic Variants Explaining Up to Half the Variation in Circulating Vascular Endothelial Growth Factor Levels
- 2011
-
Ingår i: Circulation Research. - 0009-7330 .- 1524-4571. ; 109:5, s. 554-563
-
Tidskriftsartikel (refereegranskat)abstract
- Rationale: Vascular endothelial growth factor (VEGF) affects angiogenesis, atherosclerosis, and cancer. Although the heritability of circulating VEGF levels is high, little is known about its genetic underpinnings. Objective: Our aim was to identify genetic variants associated with circulating VEGF levels, using an unbiased genome-wide approach, and to explore their functional significance with gene expression and pathway analysis. Methods and Results: We undertook a genome-wide association study of serum VEGF levels in 3527 participants of the Framingham Heart Study, with preplanned replication in 1727 participants from 2 independent samples, the STANISLAS Family Study and the Prospective Investigation of the Vasculature in Uppsala Seniors study. One hundred forty single nucleotide polymorphism (SNPs) reached genome-wide significance (P<5x10(-8)). We found evidence of replication for the most significant associations in both replication datasets. In a conditional genome-wide association study, 4 SNPs mapping to 3 chromosomal regions were independently associated with circulating VEGF levels: rs6921438 and rs4416670 (6p21.1, P=6.11x10(-506) and P=1.47x10(-12)), rs6993770 (8q23.1, P=2.50x10(-16)), and rs10738760 (9p24.2, P=1.96x10(-34)). A genetic score including these 4 SNPs explained 48% of the heritability of serum VEGF levels. Six of the SNPs that reached genome-wide significance in the genome-wide association study were significantly associated with VEGF messenger RNA levels in peripheral blood mononuclear cells. Ingenuity pathway analyses showed found plausible biological links between VEGF and 2 novel genes in these loci (ZFPM2 and VLDLR). Conclusions: Genetic variants explaining up to half the heritability of serum VEGF levels were identified. These new insights provide important clues to the pathways regulating circulating VEGF levels.
|
|
21. |
|
|
22. |
- Dinsdale, Graham, et al.
(författare)
-
Intra-and inter-observer reliability of nailfold videocapillaroscopy - A possible outcome measure for systemic sclerosis-related microangiopathy
- 2017
-
Ingår i: Microvascular Research. - : Elsevier BV. - 1095-9319 .- 0026-2862. ; 112, s. 1-6
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: Our aim was to assess the reliability of nailfold capillary assessment in terms of image evaluability, image severity grade ('normal', 'early', 'active', 'late'), capillary density, capillary (apex) width, and presence of giant capillaries, and also to gain further insight into differences in these parameters between patients with systemic sclerosis (SSc), patients with primary Raynaud's phenomenon (PRP) and healthy control subjects.METHODS: Videocapillaroscopy images (magnification 300×) were acquired from all 10 digits from 173 participants: 101 patients with SSc, 22 with PRP and 50 healthy controls. Ten capillaroscopy experts from 7 European centres evaluated the images. Custom image mark-up software allowed extraction of the following outcome measures: overall grade ('normal', 'early', 'active', 'late', 'non-specific', or 'ungradeable'), capillary density (vessels/mm), mean vessel apical width, and presence of giant capillaries.RESULTS: Observers analysed a median of 129 images each. Evaluability (i.e. the availability of measures) varied across outcome measures (e.g. 73.0% for density and 46.2% for overall grade in patients with SSc). Intra-observer reliability for evaluability was consistently higher than inter- (e.g. for density, intra-class correlation coefficient [ICC] was 0.71 within and 0.14 between observers). Conditional on evaluability, both intra- and inter-observer reliability were high for grade (ICC 0.93 and 0.78 respectively), density (0.91 and 0.64) and width (0.91 and 0.85).CONCLUSIONS: Evaluability is one of the major challenges in assessing nailfold capillaries. However, when images are evaluable, the high intra- and inter-reliabilities suggest that overall image grade, capillary density and apex width have potential as outcome measures in longitudinal studies.
|
|
23. |
- Dinsdale, Graham, et al.
(författare)
-
Nailfold capillaroscopy-how many fingers should be examined to detect abnormality?
- 2019
-
Ingår i: Rheumatology (Oxford, England). - : Oxford University Press (OUP). - 1462-0332 .- 1462-0324. ; 58:2, s. 284-288
-
Tidskriftsartikel (refereegranskat)abstract
- Objectives: Nailfold capillaroscopy is being increasingly used by rheumatologists in the diagnosis of SSc. However, assessment of all nailfolds can be time-consuming in a busy outpatient clinic. Our aim was to answer the question as to how many (and which) fingers a clinician should routinely assess to capture accurately the true state. Methods: A total of 2994 assessments (by an international panel of expert observers) of 1600 images from 173 participants (101 with SSc, 22 with primary RP and 50 healthy controls) were included in this analysis. Seven single-finger or finger combinations (derived from the middle and ring fingers) were then tested for sensitivity for the presence of two markers of capillary abnormality [presence of giant capillaries and an SSc grade (early, active or late)] compared with assessment of all eight fingers. Results: For the eight-finger gold standard, sensitivity against the diagnostic criteria was 74.6% (53.0% for the presence of giants alone and 73.1% for image grade alone). Examining only one finger gave low sensitivity (ranging from right middle 31.7% to left ring 46.6%). Examining both ring fingers gave a sensitivity of 59.8%, whereas examining the four-finger combination of both ring and both middle fingers gave a sensitivity of 66.7%. Conclusion: During routine capillaroscopic examination, ideally all eight nailbeds (excluding thumbs) should be examined, otherwise some abnormalities will be missed. Examining only four fingers reduces capillaroscopy sensitivity.
|
|
24. |
- Dinsdale, Graham, et al.
(författare)
-
Quantitative outcome measures for systemic sclerosis-related Microangiopathy – Reliability of image acquisition in Nailfold Capillaroscopy
- 2017
-
Ingår i: Microvascular Research. - : Elsevier BV. - 0026-2862. ; 113, s. 56-59
-
Tidskriftsartikel (refereegranskat)abstract
- Background Nailfold capillaroscopic parameters hold increasing promise as outcome measures for clinical trials in systemic sclerosis (SSc). Their inclusion as outcomes would often naturally require capillaroscopy images to be captured at several time points during any one study. Our objective was to assess repeatability of image acquisition (which has been little studied), as well as of measurement. Method 41 patients (26 with SSc, 15 with primary Raynaud's phenomenon) and 10 healthy controls returned for repeat high-magnification (300 ×) videocapillaroscopy mosaic imaging of 10 digits one week after initial imaging (as part of a larger study of reliability). Images were assessed in a random order by an expert blinded observer and 4 outcome measures extracted: (1) overall image grade and then (where possible) distal vessel locations were marked, allowing (2) vessel density (across the whole nailfold) to be calculated (3) apex width measurement and (4) giant vessel count. Intra-rater, intra-visit and intra-rater inter-visit (baseline vs. 1 week) reliability were examined in 475 and 392 images respectively. A linear, mixed-effects model was used to estimate variance components, from which intra-class correlation coefficients (ICCs) were determined. Results Intra-visit and inter-visit reliability estimates (ICCs) were (respectively): overall image grade, 0.97 and 0.90; vessel density, 0.92 and 0.65; mean vessel width, 0.91 and 0.79; presence of giant capillary, 0.68 and 0.56. These estimates were conditional on each parameter being measurable. Conclusion Within-operator image analysis and acquisition are reproducible. Quantitative nailfold capillaroscopy, at least with a single observer, provides reliable outcome measures for clinical studies including randomised controlled trials.
|
|
25. |
|
|
26. |
- Elhai, Muriel, et al.
(författare)
-
Mapping and predicting mortality from systemic sclerosis
- 2017
-
Ingår i: Annals of the Rheumatic Diseases. - : BMJ. - 0003-4967 .- 1468-2060. ; 76:11, s. 1897-1905
-
Tidskriftsartikel (refereegranskat)abstract
- Objectives To determine the causes of death and risk factors in systemic sclerosis (SSc). Methods Between 2000 and 2011, we examined the death certificates of all French patients with SSc to determine causes of death. Then we examined causes of death and developed a score associated with all-cause mortality from the international European Scleroderma Trials and Research (EUSTAR) database. Candidate prognostic factors were tested by Cox proportional hazards regression model by single variable analysis, followed by a multiple variable model stratified by centres. The bootstrapping technique was used for internal validation. Results We identified 2719 French certificates of deaths related to SSc, mainly from cardiac (31%) and respiratory (18%) causes, and an increase in SSc-specific mortality over time. Over a median follow-up of 2.3 years, 1072 (9.6%) of 11 193 patients from the EUSTAR sample died, from cardiac disease in 27% and respiratory causes in 17%. By multiple variable analysis, a risk score was developed, which accurately predicted the 3-year mortality, with an area under the curve of 0.82. The 3-year survival of patients in the upper quartile was 53%, in contrast with 98% in the first quartile. Conclusion Combining two complementary and detailed databases enabled the collection of an unprecedented 3700 deaths, revealing the major contribution of the cardiopulmonary system to SSc mortality. We also developed a robust score to risk-stratify these patients and estimate their 3-year survival. With the emergence of new therapies, these important observations should help caregivers plan and refine the monitoring and management to prolong these patients' survival.
|
|
27. |
- Feigin, Valery L., et al.
(författare)
-
Global, regional, and national burden of neurological disorders, 1990–2016 : a systematic analysis for the Global Burden of Disease Study 2016
- 2019
-
Ingår i: Lancet Neurology. - : Elsevier. - 1474-4422 .- 1474-4465. ; 18:5, s. 459-480
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Neurological disorders are increasingly recognised as major causes of death and disability worldwide. The aim of this analysis from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2016 is to provide the most comprehensive and up-to-date estimates of the global, regional, and national burden from neurological disorders.Methods: We estimated prevalence, incidence, deaths, and disability-adjusted life-years (DALYs; the sum of years of life lost [YLLs] and years lived with disability [YLDs]) by age and sex for 15 neurological disorder categories (tetanus, meningitis, encephalitis, stroke, brain and other CNS cancers, traumatic brain injury, spinal cord injury, Alzheimer's disease and other dementias, Parkinson's disease, multiple sclerosis, motor neuron diseases, idiopathic epilepsy, migraine, tension-type headache, and a residual category for other less common neurological disorders) in 195 countries from 1990 to 2016. DisMod-MR 2.1, a Bayesian meta-regression tool, was the main method of estimation of prevalence and incidence, and the Cause of Death Ensemble model (CODEm) was used for mortality estimation. We quantified the contribution of 84 risks and combinations of risk to the disease estimates for the 15 neurological disorder categories using the GBD comparative risk assessment approach.Findings: Globally, in 2016, neurological disorders were the leading cause of DALYs (276 million [95% UI 247–308]) and second leading cause of deaths (9·0 million [8·8–9·4]). The absolute number of deaths and DALYs from all neurological disorders combined increased (deaths by 39% [34–44] and DALYs by 15% [9–21]) whereas their age-standardised rates decreased (deaths by 28% [26–30] and DALYs by 27% [24–31]) between 1990 and 2016. The only neurological disorders that had a decrease in rates and absolute numbers of deaths and DALYs were tetanus, meningitis, and encephalitis. The four largest contributors of neurological DALYs were stroke (42·2% [38·6–46·1]), migraine (16·3% [11·7–20·8]), Alzheimer's and other dementias (10·4% [9·0–12·1]), and meningitis (7·9% [6·6–10·4]). For the combined neurological disorders, age-standardised DALY rates were significantly higher in males than in females (male-to-female ratio 1·12 [1·05–1·20]), but migraine, multiple sclerosis, and tension-type headache were more common and caused more burden in females, with male-to-female ratios of less than 0·7. The 84 risks quantified in GBD explain less than 10% of neurological disorder DALY burdens, except stroke, for which 88·8% (86·5–90·9) of DALYs are attributable to risk factors, and to a lesser extent Alzheimer's disease and other dementias (22·3% [11·8–35·1] of DALYs are risk attributable) and idiopathic epilepsy (14·1% [10·8–17·5] of DALYs are risk attributable).Interpretation: Globally, the burden of neurological disorders, as measured by the absolute number of DALYs, continues to increase. As populations are growing and ageing, and the prevalence of major disabling neurological disorders steeply increases with age, governments will face increasing demand for treatment, rehabilitation, and support services for neurological disorders. The scarcity of established modifiable risks for most of the neurological burden demonstrates that new knowledge is required to develop effective prevention and treatment strategies.Funding: Bill & Melinda Gates Foundation.
|
|
28. |
- Fergusson, Joannah R., et al.
(författare)
-
CD161 Defines a Transcriptional and Functional Phenotype across Distinct Human T Cell Lineages
- 2014
-
Ingår i: Cell Reports. - : Elsevier BV. - 2211-1247. ; 9:3, s. 1075-1088
-
Tidskriftsartikel (refereegranskat)abstract
- The C-type lectin CD161 is expressed by a large proportion of human T lymphocytes of all lineages, including a population known as mucosal-associated invariant T (MAIT) cells. To understand whether different T cell subsets expressing CD161 have similar properties, we examined these populations in parallel using mass cytometry and mRNA microarray approaches. The analysis identified a conserved CD161++/MAIT cell transcriptional signature enriched in CD161+CD8+ T cells, which can be extended to CD161+ CD4+ and CD161+TCR gamma delta+ T cells. Furthermore, this led to the identification of a shared innate-like, TCR-independent response to interleukin (IL)-12 plus IL-18 by different CD161-expressing T cell populations. This response was independent of regulation by CD161, which acted as a costimulatory molecule in the context of T cell receptor stimulation. Expression of CD161 hence identifies a transcriptional and functional phenotype, shared across human T lymphocytes and independent of both T cell receptor (TCR) expression and cell lineage.
|
|
29. |
- Foeldvari, Ivan, et al.
(författare)
-
Differences Sustained Between Diffuse and Limited Forms of Juvenile Systemic Sclerosis in an Expanded International Cohort
- 2022
-
Ingår i: Arthritis care & research. - : John Wiley & Sons. - 2151-464X .- 2151-4658. ; 74:10, s. 1575-1584
-
Tidskriftsartikel (refereegranskat)abstract
- Objective To evaluate the baseline clinical characteristics of juvenile systemic sclerosis (SSc) patients in the international juvenile SSc inception cohort, and to compare these characteristics between the classically defined juvenile diffuse cutaneous SSc (dcSSc) and limited cutaneous SSc (lcSSc) subtypes and among those with overlap features. Methods A cross-sectional study was performed using baseline visit data. Information on demographic characteristics, organ system evaluation, treatment, and patient- and physician-reported outcomes was extracted and summary statistics applied. Comparisons between juvenile dcSSc and lcSSc subtypes and patients with and without overlap features were performed using chi-square and Mann-Whitney U tests. Results At data extraction, 150 juvenile SSc patients were enrolled across 42 centers; 83% were White, 80% were female, juvenile dcSSc predominated (72%), and 17% of the cohort had overlap features. Significant differences were found between juvenile dcSSc and juvenile lcSSc regarding modified Rodnan skin thickness score, the presence of Gottron's papules, digital tip ulceration, results of the 6-minute walk test, and composite pulmonary and cardiac involvement. All of these were more frequent in dcSSc except for cardiac involvement. Juvenile dcSSc patients had significantly worse scores for physician-rated disease activity and damage. A significantly higher occurrence of Gottron's papules and musculoskeletal and composite pulmonary involvement, and a significantly lower frequency of Raynaud's phenomenon, were seen in those with overlap features. Conclusion Results from a large international juvenile SSc cohort demonstrate significant differences between juvenile dcSSc and juvenile lcSSc patients, including more globally severe disease and increased frequency of interstitial lung disease in juvenile dcSSc patients, while those with lcSSc have more frequent cardiac involvement. Those with overlap features had an unexpected higher frequency of interstitial lung disease.
|
|
30. |
- Foeldvari, Ivan, et al.
(författare)
-
Gender differences in juvenile systemic sclerosis patients : Results from the international juvenile scleroderma inception cohort
- 2023
-
Ingår i: Journal of Scleroderma and Related Disorders. - : Sage Publications. - 2397-1983 .- 2397-1991. ; 8:2, s. 120-130
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: To compare organ involvement and disease severity between male and female patients with juvenile onset systemic sclerosis.Methods: Demographics, organ involvement, laboratory evaluation, patient-reported outcomes and physician assessment variables were compared between male and female juvenile onset systemic sclerosis patients enrolled in the prospective international juvenile systemic sclerosis cohort at their baseline visit and after 12 months.Results: One hundred and seventy-five juvenile onset systemic sclerosis patients were evaluated, 142 females and 33 males. Race, age of onset, disease duration, and disease subtypes (70% diffuse cutaneous) were similar between males and females. Active digital ulceration, very low body mass index, and tendon friction rubs were significantly more frequent in males. Physician global assessment of disease severity and digital ulcer activity was significantly higher in males. Composite pulmonary involvement was also more frequent in males, though not statistically significantly. After 12 months, they are the pattern of differences changed female patients had significantly more frequent pulmonary involvement.Conclusion: In this cohort, juvenile onset systemic sclerosis had a more severe course in males at baseline and but the pattern changed after 12 months. Some differences from adult findings persisted, there is no increased signal of pulmonary arterial hypertension or heart failure in male pediatric patients. While monitoring protocols of organ involvement in juvenile onset systemic sclerosis need to be identical for males and females.
|
|
31. |
- Foeldvari, Ivan, et al.
(författare)
-
Underdetection of Interstitial Lung Disease in Juvenile Systemic Sclerosis
- 2022
-
Ingår i: Arthritis care & research. - : John Wiley & Sons. - 2151-464X .- 2151-4658. ; 74:3, s. 364-370
-
Tidskriftsartikel (refereegranskat)abstract
- Objective. Utilizing data obtained from a prospective, international, juvenile systemic sclerosis (SSc) cohort, the present study was undertaken to determine if pulmonary screening with forced vital capacity (FVC) and diffusing capacity for carbon monoxide (DLco) is sufficient to assess the presence of interstitial lung disease (ILD) in comparison to high-resolution computed tomography (HRCT) in juvenile SSc. Methods. The juvenile SSc cohort database was queried for patients enrolled from January 2008 to January 2020 with recorded pulmonary function tests (PFTs) parameters and HRCT to determine the discriminatory properties of P FT parameters, FVC, and DLco in detecting ILD. Results. Eighty-six juvenile SSc patients had both computed tomography imaging and FVC values for direct comparison. Using findings on HRCT as the standard measure of ILD presence, the sensitivity of FVC in detecting ILD in juvenile SSc was only 40%, the specificity was 77%, and area under the curve (AUC) was 0.58. Fifty-eight juvenile SSc patients had both CT imaging and DLco values for comparison. The sensitivity of DLco in detecting ILD was 76%, the specificity was 70%, and AUC was 0.73. Conclusion. The performance of PFTs in juvenile SSc to detect underlying ILD was quite limited. Specifically, the FVC, which is one of the main clinical parameters in adult SSc to detect and monitor ILD, would miss -60% of children who had ILD changes on their accompanying HRCT. The DLco was more sensitive in detecting potential abnormalities on HRCT, but with less specificity than the FVC. These results support the use of HRCT in tandem with PFTs for the screening of ILD in juvenile SSc.
|
|
32. |
|
|
33. |
- Gorlova, Olga, et al.
(författare)
-
Identification of Novel Genetic Markers Associated with Clinical Phenotypes of Systemic Sclerosis through a Genome-Wide Association Strategy
- 2011
-
Ingår i: PLoS Genetics. - : Public Library of Science (PLoS). - 1553-7404. ; 7:7
-
Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to determine, through a genome-wide association study (GWAS), the genetic components contributing to different clinical sub-phenotypes of systemic sclerosis (SSc). We considered limited (IcSSc) and diffuse (dcSSc) cutaneous involvement, and the relationships with presence of the SSc-specific auto-antibodies, anti-centromere (ACA), and anti-topoisomerase I (ATA). Four GWAS cohorts, comprising 2,296 SSc patients and 5,171 healthy controls, were meta-analyzed looking for associations in the selected subgroups. Eighteen polymorphisms were further tested in nine independent cohorts comprising an additional 3,175 SSc patients and 4,971 controls. Conditional analysis for associated SNPs in the HLA region was performed to explore their independent association in antibody subgroups. Overall analysis showed that non-HLA polymorphism rs11642873 in IRF8 gene to be associated at GWAS level with lcSSc (P = 2.32x10(-12), OR = 0.75). Also, rs12540874 in GRB10 gene (P = 1.27 x 10(-6), OR = 1.15) and rs11047102 in SOX5 gene (P = 1.39x10(-7), OR = 1.36) showed a suggestive association with lcSSc and ACA subgroups respectively. In the HLA region, we observed highly associated allelic combinations in the HLA-DQB1 locus with ACA (P = 1.79x10(-61), OR = 2.48), in the HLA-DPA1/B1 loci with ATA (P = 4.57x10(-76), OR = 8.84), and in NOTCH4 with ACA P = 8.84x10(-21), OR = 0.55) and ATA (P = 1.14x10(-8), OR = 0.54). We have identified three new non-HLA genes (IRF8, GRB10, and SOX5) associated with SSc clinical and autoantibody subgroups. Within the HLA region, HLA-DQB1, HLA-DPA1/B1, and NOTCH4 associations with SSc are likely confined to specific auto-antibodies. These data emphasize the differential genetic components of subphenotypes of SSc.
|
|
34. |
- Guida, Florence, et al.
(författare)
-
The blood metabolome of incident kidney cancer: A case-control study nested within the MetKid consortium
- 2021
-
Ingår i: PLoS Medicine. - : Public Library of Science (PLOS). - 1549-1277 .- 1549-1676. ; 18:9
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Excess bodyweight and related metabolic perturbations have been implicated in kidney cancer aetiology, but the specific molecular mechanisms underlying these relationships are poorly understood. In this study, we sought to identify circulating metabolites that predispose kidney cancer and to evaluate the extent to which they are influenced by body mass index (BMI).Methods and findings: We assessed the association between circulating levels of 1,416 metabolites and incident kidney cancer using pre-diagnostic blood samples from up to 1,305 kidney cancer case–control pairs from 5 prospective cohort studies. Cases were diagnosed on average 8 years after blood collection. We found 25 metabolites robustly associated with kidney cancer risk. In particular, 14 glycerophospholipids (GPLs) were inversely associated with risk, including 8 phosphatidylcholines (PCs) and 2 plasmalogens. The PC with the strongest association was PC ae C34:3 with an odds ratio (OR) for 1 standard deviation (SD) increment of 0.75 (95% confidence interval [CI]: 0.68 to 0.83, p = 2.6 × 10−8). In contrast, 4 amino acids, including glutamate (OR for 1 SD = 1.39, 95% CI: 1.20 to 1.60, p = 1.6 × 10−5), were positively associated with risk. Adjusting for BMI partly attenuated the risk association for some—but not all—metabolites, whereas other known risk factors of kidney cancer, such as smoking and alcohol consumption, had minimal impact on the observed associations. A mendelian randomisation (MR) analysis of the influence of BMI on the blood metabolome highlighted that some metabolites associated with kidney cancer risk are influenced by BMI. Specifically, elevated BMI appeared to decrease levels of several GPLs that were also found inversely associated with kidney cancer risk (e.g., −0.17 SD change [ßBMI] in 1-(1-enyl-palmitoyl)-2-linoleoyl-GPC (P-16:0/18:2) levels per SD change in BMI, p = 3.4 × 10−5). BMI was also associated with increased levels of glutamate (ßBMI: 0.12, p = 1.5 × 10−3). While our results were robust across the participating studies, they were limited to study participants of European descent, and it will, therefore, be important to evaluate if our findings can be generalised to populations with different genetic backgrounds.Conclusions: This study suggests a potentially important role of the blood metabolome in kidney cancer aetiology by highlighting a wide range of metabolites associated with the risk of developing kidney cancer and the extent to which changes in levels of these metabolites are driven by BMI - the principal modifiable risk factor of kidney cancer.
|
|
35. |
- Haverd, Vanessa, et al.
(författare)
-
A new version of the CABLE land surface model (Subversion revision r4601) incorporating land use and land cover change, woody vegetation demography, and a novel optimisation-based approach to plant coordination of photosynthesis
- 2018
-
Ingår i: Geoscientific Model Development. - : Copernicus GmbH. - 1991-959X .- 1991-9603. ; 11:7, s. 2995-3026
-
Tidskriftsartikel (refereegranskat)abstract
- The Community Atmosphere-Biosphere Land Exchange model (CABLE) is a land surface model (LSM) that can be applied stand-alone and provides the land surface-atmosphere exchange within the Australian Community Climate and Earth System Simulator (ACCESS). We describe new developments that extend the applicability of CABLE for regional and global carbon-climate simulations, accounting for vegetation responses to biophysical and anthropogenic forcings. A land use and land cover change module driven by gross land use transitions and wood harvest area was implemented, tailored to the needs of the Coupled Model Intercomparison Project 6 (CMIP6). Novel aspects include the treatment of secondary woody vegetation, which benefits from a tight coupling between the land use module and the Population Orders Physiology (POP) module for woody demography and disturbance-mediated landscape heterogeneity. Land use transitions and harvest associated with secondary forest tiles modify the annually resolved patch age distribution within secondary vegetated tiles, in turn affecting biomass accumulation and turnover rates and hence the magnitude of the secondary forest sink. Additionally, we implemented a novel approach to constrain modelled GPP consistent with the coordination hypothesis and predicted by evolutionary theory, which suggests that electron-transport- and Rubisco-limited rates adjust seasonally and across biomes to be co-limiting. We show that the default prior assumption - common to CABLE and other LSMs - of a fixed ratio of electron transport to carboxylation capacity at standard temperature (Jmax,0/Vcmax,0) is at odds with this hypothesis; we implement an alternative algorithm for dynamic optimisation of this ratio such that coordination is achieved as an outcome of fitness maximisation. The results have significant implications for the magnitude of the simulated CO2 fertilisation effect on photosynthesis in comparison to alternative estimates and observational proxies. These new developments enhance CABLE's capability for use within an Earth system model and in stand-alone applications to attribute trends and variability in the terrestrial carbon cycle to regions, processes and drivers. Model evaluation shows that the new model version satisfies several key observational constraints: (i) trend and interannual variations in the global land carbon sink, including sensitivities of interannual variations to global precipitation and temperature anomalies; (ii) centennial trends in global GPP; (iii) coordination of Rubisco-limited and electron-transport-limited photosynthesis; (iv) spatial distributions of global ET, GPP, biomass and soil carbon; and (v) age-dependent rates of biomass accumulation in boreal, temperate and tropical secondary forests. CABLE simulations agree with recent independent assessments of the global land-atmosphere flux partition that use a combination of atmospheric inversions and bottom-up constraints. In particular, there is agreement that the strong CO2-driven sink in the tropics is largely cancelled by net deforestation and forest degradation emissions, leaving the Northern Hemisphere (NH) extratropics as the dominant contributor to the net land sink.
|
|
36. |
- Haverd, Vanessa, et al.
(författare)
-
A stand-alone tree demography and landscape structure module for Earth system models
- 2013
-
Ingår i: Geophysical Research Letters. - : American Geophysical Union (AGU). - 1944-8007 .- 0094-8276. ; 40:19, s. 5234-5239
-
Tidskriftsartikel (refereegranskat)abstract
- We propose and demonstrate a new approach for the simulation of woody ecosystem stand dynamics, demography, and disturbance-mediated heterogeneity suitable for continental to global applications and designed for coupling to the terrestrial ecosystem component of any earth system model. The approach is encoded in a model called Populations-Order-Physiology (POP). We demonstrate the behavior and performance of POP coupled to the Community Atmosphere Biosphere Land Exchange model (CABLE) applied along the Northern Australian Tropical Transect, featuring gradients in rainfall and fire disturbance. The model is able to simultaneously reproduce observation-based estimates of key functional and structural variables along the transect, namely gross primary production, tree foliage projective cover, basal area, and maximum tree height. Prospects for the use of POP to address current vegetation dynamic deficiencies in earth system modeling are discussed.
|
|
37. |
- Haverd, Vanessa, et al.
(författare)
-
Carbon cycle responses of semi-arid ecosystems to positive asymmetry in rainfall
- 2017
-
Ingår i: Global Change Biology. - : Wiley. - 1365-2486 .- 1354-1013. ; 23:2, s. 793-800
-
Tidskriftsartikel (refereegranskat)abstract
- Recent evidence shows that warm semi-arid ecosystems are playing a disproportionate role in the interannual variability and greening trend of the global carbon cycle given their mean lower productivity when compared with other biomes (Ahlström et al. 2015 Science, 348, 895). Using multiple observations (land-atmosphere fluxes, biomass, streamflow and remotely sensed vegetation cover) and two state-of-the-art biospheric models, we show that climate variability and extremes lead to positive or negative responses in the biosphere, depending on vegetation type. We find Australia to be a global hot spot for variability, with semi-arid ecosystems in that country exhibiting increased carbon uptake due to both asymmetry in the interannual distribution of rainfall (extrinsic forcing), and asymmetry in the response of gross primary production (GPP) to rainfall change (intrinsic response). The latter is attributable to the pulse-response behaviour of the drought-adapted biota of these systems, a response that is estimated to be as much as half of that from the CO2 fertilization effect during 1990–2013. Mesic ecosystems, lacking drought-adapted species, did not show an intrinsic asymmetric response. Our findings suggest that a future more variable climate will induce large but contrasting ecosystem responses, differing among biomes globally, independent of changes in mean precipitation alone. The most significant changes are occurring in the extensive arid and semi-arid regions, and we suggest that the reported increased carbon uptake in response to asymmetric responses might be contributing to the observed greening trends there.
|
|
38. |
- Haverd, Vanessa, et al.
(författare)
-
Dryland vegetation response to wet episode, not inherent shift in sensitivity to rainfall, behind Australia's role in 2011 global carbon sink anomaly
- 2016
-
Ingår i: Global Change Biology. - : Wiley. - 1354-1013. ; 22:7, s. 2315-2316
-
Tidskriftsartikel (refereegranskat)abstract
- There is compelling new evidence that semi-arid ecosystems are playing a pivotal role in the inter-annual variability and greening trend of the global carbon cycle (Ahlström et al., 2015). The situation is exemplified by the vast inland region of Australia, the driest inhabited continent. Using a global model, Poulter et al. (2014) inferred that Australian ecosystems contributed 57% of a record global carbon uptake anomaly in 2011, and have entered a regime of enhanced sensitivity to rainfall since the mid-1990s. This article is protected by copyright. All rights reserved.
|
|
39. |
- Haverd, Vanessa, et al.
(författare)
-
Higher than expected CO2 fertilization inferred from leaf to global observations
- 2020
-
Ingår i: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 26:4, s. 2390-2402
-
Tidskriftsartikel (refereegranskat)abstract
- Several lines of evidence point to an increase in the activity of the terrestrial biosphere over recent decades, impacting the global net land carbon sink (NLS) and its control on the growth of atmospheric carbon dioxide (ca). Global terrestrial gross primary production (GPP)—the rate of carbon fixation by photosynthesis—is estimated to have risen by (31 ± 5)% since 1900, but the relative contributions of different putative drivers to this increase are not well known. Here we identify the rising atmospheric CO2 concentration as the dominant driver. We reconcile leaf-level and global atmospheric constraints on trends in modeled biospheric activity to reveal a global CO2 fertilization effect on photosynthesis of 30% since 1900, or 47% for a doubling of ca above the pre-industrial level. Our historic value is nearly twice as high as current estimates (17 ± 4)% that do not use the full range of available constraints. Consequently, under a future low-emission scenario, we project a land carbon sink (174 PgC, 2006–2099) that is 57 PgC larger than if a lower CO2 fertilization effect comparable with current estimates is assumed. These findings suggest a larger beneficial role of the land carbon sink in modulating future excess anthropogenic CO2 consistent with the target of the Paris Agreement to stay below 2°C warming, and underscore the importance of preserving terrestrial carbon sinks.
|
|
40. |
- Haverd, Vanessa, et al.
(författare)
-
Process contributions of Australian ecosystems to interannual variations in the carbon cycle
- 2016
-
Ingår i: Environmental Research Letters. - : IOP Publishing. - 1748-9326. ; 11:5
-
Tidskriftsartikel (refereegranskat)abstract
- New evidence is emerging that semi-arid ecosystems dominate interannual variability (IAV) of the global carbon cycle, largely via fluctuating water availability associated with El Niño/Southern Oscillation. Recent evidence from global terrestrial biosphere modelling and satellite-based inversion of atmospheric CO2 point to a large role of Australian ecosystems in global carbon cycle variability, including a large contribution from Australia to the record land sink of 2011. However the specific mechanisms governing this variability, and their bioclimatic distribution within Australia, have not been identified. Here we provide a regional assessment, based on best available observational data, of IAV in the Australian terrestrial carbon cycle and the role of Australia in the record land sink anomaly of 2011. We find that IAV in Australian net carbon uptake is dominated by semi-arid ecosystems in the east of the continent, whereas the 2011 anomaly was more uniformly spread across most of the continent. Further, and in contrast to global modelling results suggesting that IAV in Australian net carbon uptake is amplified by lags between production and decomposition, we find that, at continental scale, annual variations in production are dampened by annual variations in decomposition, with both fluxes responding positively to precipitation anomalies.
|
|
41. |
- Ingegnoli, Francesca, et al.
(författare)
-
A comparison between nailfold capillaroscopy patterns in adulthood in juvenile and adult-onset systemic sclerosis: A EUSTAR exploratory study
- 2015
-
Ingår i: Microvascular Research. - : Elsevier BV. - 1095-9319 .- 0026-2862. ; 102, s. 19-24
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: Qualitative capillaroscopy patterns in juvenile- and adult-onset systemic sclerosis (SSc) were studied in adulthood using data from the EULAR Scleroderma Trials and Research (EUSTAR) database. Methods: Data collected between June 2004 and April 2013 were examined with focus on capillaroscopy. In this retrospective exploratory study, series of patients with juvenile-onset SSc were matched with series of adult-onset SSc having the same gender and autoantibody profile. Results: 30 of 123 patients with juvenile-onset and 2108 of 7133 with adult-onset SSc had data on capillaroscopy. Juvenile-onset SSc showed scleroderma pattern more frequently than adult-onset SSc (93.3% and 88%). The OR was 2.44 and 95% Cl 0.57-10.41. An active scleroderma pattern was present in 58% of juvenile- and 61% of adult-onset SSc. The OR was 0.91 and 95% Cl 0.28-2.93. The late scleroderma pattern was present in 61% of juvenile- and 55.5% of adult-onset SSc. The OR was 1.06 and 95% Cl 0.34-3.56. Conclusion: This is the first exploratory study on the comparison of capillaroscopy between juvenile- and adult-onset SSc in adulthood. Juvenile-onset SSc had an increase prevalence of sderoderma pattern, but a similar distribution of the three patterns was suggested. Further studies are needed to define this issue. (C) 2015 Elsevier Inc. All rights reserved.
|
|
42. |
- Ingegnoli, Francesca, et al.
(författare)
-
Nailfold capillaroscopy in systemic sclerosis: Data from the EULAR scleroderma trials and research (EUSTAR) database
- 2013
-
Ingår i: Microvascular Research. - : Elsevier BV. - 1095-9319 .- 0026-2862. ; 89, s. 122-128
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: The aims of this study were to obtain cross-sectional data on capillaroscopy in an international multi-center cohort of Systemic Sclerosis (SSc) and to investigate the frequency of the capillaroscopic patterns and their disease-phenotype associations. Methods: Data collected between June 2004 and October 2011 in the EULAR Scleroderma Trials and Research (EUSTAR) registry were examined. Patients' profiles based on clinical and laboratory data were obtained by cluster analysis and the association between profiles and capillaroscopy was investigated by multinomial logistic regression. Results: 62 of the 110 EUSTAR centers entered data on capillaroscopy in the EUSTAR database. 376 of the 2754 patients (13.65%) were classified as scleroderma pattern absent, but non-specific capillary abnormalities were noted in 55.48% of the cases. Four major patients' profiles were identified characterized by a progressive severity for skin involvement, as well as an increased number of systemic manifestations. The "early" and "active" scleroderma patterns were generally observed in patients with mild/moderate skin involvement and a low number of disease manifestations, while the "late" scleroderma pattern was found more frequently in the more severe forms of the disease. Conclusion: These data indicate the importance of capillaroscopy in SSc management and that capillaroscopic patterns are directly related to the extent of organ involvement. (C) 2013 Elsevier Inc. All rights reserved.
|
|
43. |
|
|
44. |
|
|
45. |
- Kowal-Bielecka, Otylia, et al.
(författare)
-
Update of EULAR recommendations for the treatment of systemic sclerosis
- 2017
-
Ingår i: Annals of the Rheumatic Diseases. - : BMJ. - 0003-4967 .- 1468-2060. ; 76, s. 1327-1339
-
Tidskriftsartikel (refereegranskat)abstract
- The aim was to update the 2009 European League against Rheumatism (EULAR) recommendations for the treatment of systemic sclerosis (SSc), with attention to new therapeutic questions. Update of the previous treatment recommendations was performed according to EULAR standard operating procedures. The task force consisted of 32 SSc clinical experts from Europe and the USA, 2 patients nominated by the pan-European patient association for SSc (Federation of European Scleroderma Associations (FESCA)), a clinical epidemiologist and 2 research fellows. All centres from the EULAR Scleroderma Trials and Research group were invited to submit and select clinical questions concerning SSc treatment using a Delphi approach. Accordingly, 46 clinical questions addressing 26 different interventions were selected for systematic literature review. The new recommendations were based on the available evidence and developed in a consensus meeting with clinical experts and patients. The procedure resulted in 16 recommendations being developed (instead of 14 in 2009) that address treatment of several SSc-related organ complications: Raynaud's phenomenon (RP), digital ulcers (DUs), pulmonary arterial hypertension (PAH), skin and lung disease, scleroderma renal crisis and gastrointestinal involvement. Compared with the 2009 recommendations, the 2016 recommendations include phosphodiesterase type 5 (PDE-5) inhibitors for the treatment of SSc-related RP and DUs, riociguat, new aspects for endothelin receptor antagonists, prostacyclin analogues and PDE-5 inhibitors for SSc-related PAH. New recommendations regarding the use of fluoxetine for SSc-related RP and haematopoietic stem cell transplantation for selected patients with rapidly progressive SSc were also added. In addition, several comments regarding other treatments addressed in clinical questions and suggestions for the SSc research agenda were formulated. These updated data-derived and consensus-derived recommendations will help rheumatologists to manage patients with SSc in an evidence-based way. These recommendations also give directions for future clinical research in SSc.
|
|
46. |
- Lazzaroni, Maria Grazia, et al.
(författare)
-
Malignancies in patients with anti-RNA polymerase III antibodies and systemic sclerosis : Analysis of the EULAR scleroderma trials and research cohort and possible recommendations for screening
- 2017
-
Ingår i: Journal of Rheumatology. - : The Journal of Rheumatology. - 0315-162X .- 1499-2752. ; 44:5, s. 639-647
-
Tidskriftsartikel (refereegranskat)abstract
- Objective. To analyze the characteristics of anti-RNA polymerase III antibodies (anti-RNAP3)- positive patients with systemic sclerosis (SSc) in the European League Against Rheumatism Scleroderma Trials and Research group (EUSTAR) registry with a focus on the risk of cancer and the characteristics of malignancies, and the aim to provide guidelines about potential cancer screening in these patients. Methods. (1) Analysis of the EUSTAR database: 4986 patients with information on their anti-RNAP3 status were included. (2) Case-control study: additional retrospective data, including malignancy history, were queried in 13 participating EUSTAR centers; 158 anti-RNAP3+ cases were compared with 199 local anti-RNAP3- controls, matched for sex, cutaneous subset, disease duration, and age at SSc onset. (3) A Delphi exercise was performed by 82 experts to reach consensus for cancer screening in anti-RNAP3+ patients. Results. In the EUSTAR registry, anti-RNAP3 were associated in multivariable analysis with renal crisis and diffuse cutaneous involvement. In the case-control study, anti-RNAP3 were associated with gastric antral vascular ectasia, rapid progression of skin involvement, and malignancies concomitant to SSc onset (OR 7.38, 95% CI 1.61-33.8). When compared with other anti-RNAP3+ patients, those with concomitant malignancies had older age (p < 0.001) and more frequent diffuse cutaneous involvement (p = 0.008). The Delphi exercise highlighted the need for malignancy screening at the time of diagnosis for anti-RNAP3+ patients and tight followup in the following years. Conclusion. Anti-RNAP3+ patients with SSc have a high risk of concomitant malignancy. These results have implications for clinical practice and suggest regular screening for cancer in anti-RNAP3+ patients.
|
|
47. |
- Lepri, Gemma, et al.
(författare)
-
Systemic sclerosis and primary biliary cholangitis : Longitudinal data to determine the outcomes
- 2023
-
Ingår i: Journal of Scleroderma and Related Disorders. - 2397-1983. ; 8:3, s. 210-220
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Several studies described the cross-sectional characteristics of systemic sclerosis patients and coexisting primary biliary cholangitis, but longitudinal prognostic data are lacking. Aims: To describe the systemic sclerosis–primary biliary cholangitis phenotype, including baseline characteristics and outcomes. Methods: We performed a multicentre the European Scleroderma Trials and Research Group study of systemic sclerosis patients with primary biliary cholangitis or with primary biliary cholangitis–specific antibodies, matched with systemic sclerosis controls free from hepatobiliary involvement matched for disease duration and cutaneous subset. Data were recorded at baseline and at the last available visit. Results: A total of 261 patients were enrolled (115 primary biliary cholangitis–systemic sclerosis, 161 systemic sclerosis). At baseline, systemic sclerosis–primary biliary cholangitis patients had a higher prevalence of anti-centromere antibodies (p = 0.0023) and a lower prevalence of complete absence of digital ulcers. The milder vascular involvement was confirmed at follow-up when crucial differences emerged in the percentage of patients experiencing digital ulcers; a significantly higher number of patients who never experienced digital ulcers were observed among primary biliary cholangitis–systemic sclerosis patients (p = 0.0015). Moreover, a greater incidence of pulmonary arterial hypertension (p < 0.001) and of conduction blocks (p = 0.0256) was observed in systemic sclerosis patients without primary biliary cholangitis. Patients with primary biliary cholangitis had higher levels of liver enzymes at baseline than systemic sclerosis patients; a significant decrease in liver enzymes was observed at follow-up. Out of 18 patients with cholangitis, one received a liver transplant at follow-up. Conclusion: Our data show that systemic sclerosis–primary biliary cholangitis exhibit a mild systemic sclerosis and primary biliary cholangitis phenotype with outcomes being in general favourable.
|
|
48. |
- Meehan, Sue Ann, et al.
(författare)
-
Reducing Initial Loss to Follow-up Among People With Bacteriologically Confirmed Tuberculosis : LINKEDin, a Quasi-experimental Study in South Africa
- 2024
-
Ingår i: Open Forum Infectious Diseases. - 2328-8957. ; 11:1
-
Tidskriftsartikel (refereegranskat)abstract
- Every person diagnosed with tuberculosis (TB) needs to initiate treatment. The World Health Organization estimated that 61% of people who developed TB in 2021 were included in a TB treatment registration system. Initial loss to follow-up (ILTFU) is the loss of persons to care between diagnosis and treatment initiation/registration. LINKEDin, a quasi-experimental study, evaluated the effect of 2 interventions (hospital recording and an alert-and-response patient management intervention) in 6 subdistricts across 3 high–TB burden provinces of South Africa. Using integrated electronic reports, we identified all persons diagnosed with TB (Xpert MTB/ RIF positive) in the hospital and at primary health care facilities. We prospectively determined linkage to care at 30 days after TB diagnosis. We calculated the risk of ILTFU during the baseline and intervention periods and the relative risk reduction in ILTFU between these periods. We found a relative reduction in ILTFU of 42.4% (95% CI, 28.5%–53.7%) in KwaZulu Natal (KZN) and 22.3% (95% CI, 13.3%–30.4%) in the Western Cape (WC), with no significant change in Gauteng. In KZN and the WC, the relative reduction in ILTFU appeared greater in subdistricts where the alert-and-response patient management intervention was implemented (KZN: 49.3%; 95% CI, 32.4%–62%; vs 32.2%; 95% CI, 5.4%–51.4%; and WC: 34.2%; 95% CI, 20.9%–45.3%; vs 13.4%; 95% CI, 0.7%–24.4%). We reported a notable reduction in ILTFU in 2 provinces using existing routine health service data and applying a simple intervention to trace and recall those not linked to care. TB programs need to consider ILTFU a priority and develop interventions specific to their context to ensure improved linkage to care.
|
|
49. |
- Peterson Årsköld, Sindra, et al.
(författare)
-
Optical Spectra of Synechocystis and Spinach Photosystem II Preparations at 1.7 K: Identification of the D1-Pheophytin Energies and Stark Shifts
- 2003
-
Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 1520-5126 .- 0002-7863. ; 125:43, s. 13063-13074
-
Tidskriftsartikel (refereegranskat)abstract
- We report and compare highly resolved, simultaneously recorded absorption and CD spectra of active Photosystem II (PSII) samples in the range 440-750 nm. From an appropriately scaled comparison of spinach membrane fragment (BBY) and PSII core spectra, we show that key features of the core spectrum are quantitatively represented in the BBY data. PSII from the cyanobacterium Synechocystis 6803 display spectral features in the Qy region of comparable width (50-70 cm-1 fwhm) to those seen in plant PSII but the energies of the resolved features are distinctly different. A comparison of spectra taken of PSII poised in the S1QA and S2QA- redox states reveals electrochromic shifts largely attributable to the influence of QA- on PheoD1. This allows accurate determinations of the PheoD1 Qy absorption positions to be at 685.0 nm for spinach cores, 685.8 nm for BBY particles, and 683.0 nm for Synechocystis. These are discussed in terms of earlier reports of the PheoD1 energies in PSII. The Qx transition of PheoD1 undergoes a blue shift upon QA reduction, and we place a lower limit of 80 cm-1 on this shift in plant material. By comparing the magnitude of the Stark shifts of the Qx and Qy bands of PheoD1, the directions of the transition-induced dipole moment changes, x and y, for this functionally important pigment could be determined, assuming normal magnitudes of the 's. Consequently, x and y are determined to be approximately orthogonal to the directions expected for these transitions. Low-fluence illumination experiments at 1.7 K resulted in very efficient formation of QA-. This was accompanied by cyt b559 oxidation in BBYs and carotenoid oxidation in cores. No chlorophyll oxidation was observed. Our data allow us to estimate the quantum efficiency of PSII at this temperature to be of the order 0.1-1. No Stark shift associated with the S1-to-S2 transition of the Mn cluster is evident in our samples. The similarity of Stark data in plants and Synechocystis points to minimal interactions of PheoD1 with nearby chloropyll pigments in active PSII preparations. This appears to be at variance with interpretations of experiments performed with inactive solubilized reaction-center preparations.
|
|
50. |
- Pugh, Thomas A.M., et al.
(författare)
-
Role of forest regrowth in global carbon sink dynamics
- 2019
-
Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424. ; 116:10, s. 4382-4387
-
Tidskriftsartikel (refereegranskat)abstract
- Although the existence of a large carbon sink in terrestrial ecosystems is well-established, the drivers of this sink remain uncertain. It has been suggested that perturbations to forest demography caused by past land-use change, management, and natural disturbances may be causing a large component of current carbon uptake. Here we use a global compilation of forest age observations, combined with a terrestrial biosphere model with explicit modeling of forest regrowth, to partition the global forest carbon sink between old-growth and regrowth stands over the period 1981–2010. For 2001–2010 we find a carbon sink of 0.85 (0.66–0.96) Pg year −1 located in intact old-growth forest, primarily in the moist tropics and boreal Siberia, and 1.30 (1.03–1.96) Pg year −1 located in stands regrowing after past disturbance. Approaching half of the sink in regrowth stands would have occurred from demographic changes alone, in the absence of other environmental changes. These age-constrained results show consistency with those simulated using an ensemble of demographically-enabled terrestrial biosphere models following an independent reconstruction of historical land use and management. We estimate that forests will accumulate an additional 69 (44–131) Pg C in live biomass from changes in demography alone if natural disturbances, wood harvest, and reforestation continue at rates comparable to those during 1981–2010. Our results confirm that it is not possible to understand the current global terrestrial carbon sink without accounting for the size-able sink due to forest demography. They also imply that a large portion of the current terrestrial carbon sink is strictly transient in nature.
|
|