| 1. |
- Akselsson, Cecilia, et al.
(författare)
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Weathering rates in Swedish forest soils
- 2019
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Ingår i: Biogeosciences. - : Copernicus GmbH. - 1726-4170 .- 1726-4189. ; 16:22, s. 4429-4450
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Forskningsöversikt (refereegranskat)abstract
- Soil and water acidification was internationally recognised as a severe environmental problem in the late 1960s. The interest in establishing “critical loads” led to a peak in weathering research in the 1980s and 1990s, since base cation weathering is the long-term counterbalance to acidification pressure. Assessments of weathering rates and associated uncertainties have recently become an area of renewed research interest, this time due to demand for forest residues to provide renewable bioenergy. Increased demand for forest fuels increases the risk of depleting the soils of base cations produced in situ by weathering. This is the background to the research programme Quantifying Weathering Rates for Sustainable Forestry (QWARTS), which ran from 2012 to 2019. The programme involved research groups working at different scales, from laboratory experiments to modelling. The aims of this study were to (1) investigate the variation in published weathering rates of base cations from different approaches in Sweden, with consideration of the key uncertainties for each method; (2) assess the robustness of the results in relation to sustainable forestry; and (3) discuss the results in relation to new insights from the QWARTS programme and propose ways to further reduce uncertainties. In the study we found that the variation in estimated weathering rates at single-site level was large, but still most sites could be placed reliably in broader classes of weathering rates. At the regional level, the results from the different approaches were in general agreement. Comparisons with base cation losses after stem-only and whole-tree harvesting showed sites where whole-tree harvesting was clearly not sustainable and other sites where variation in weathering rates from different approaches obscured the overall balance. Clear imbalances appeared mainly after whole-tree harvesting in spruce forests in southern and central Sweden. Based on the research findings in the QWARTS programme, it was concluded that the PROFILE/ForSAFE family of models provides the most important fundamental understanding of the contribution of weathering to long-term availability of base cations to support forest growth. However, these approaches should be continually assessed against other approaches. Uncertainties in the model approaches can be further reduced, mainly by finding ways to reduce uncertainties in input data on soil texture and associated hydrological parameters but also by developing the models, e.g. to better represent biological feedbacks under the influence of climate change.
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| 2. |
- Albrecht, Daniel S., et al.
(författare)
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Brain glial activation in fibromyalgia - A multi-site positron emission tomography investigation
- 2019
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Ingår i: Brain, behavior, and immunity. - : Elsevier BV. - 0889-1591 .- 1090-2139. ; 75, s. 72-83
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Tidskriftsartikel (refereegranskat)abstract
- Fibromyalgia (FM) is a poorly understood chronic condition characterized by widespread musculoskeletal pain, fatigue, and cognitive difficulties. While mounting evidence suggests a role for neuroinflammation, no study has directly provided evidence of brain glial activation in FM. In this study, we conducted a Positron Emission Tomography (PET) study using [C-11]PBR28, which binds to the translocator protein (TSPO), a protein upregulated in activated microglia and astrocytes. To enhance statistical power and generalizability, we combined datasets collected independently at two separate institutions (Massachusetts General Hospital [MGH] and Karolinska Institutet [KI]). In an attempt to disentangle the contributions of different glial cell types to FM, a smaller sample was scanned at KI with [C-11]-L-deprenyl-D2 PET, thought to primarily reflect astrocytic (but not microglial) signal. Thirty-one FM patients and 27 healthy controls (HC) were examined using [C-11]PBR28 PET. 11 FM patients and 11 HC were scanned using [C-11]-L-deprenyl-D2 PET. Standardized uptake values normalized by occipital cortex signal (SUVR) and distribution volume (V-T) were computed from the [C-11]PBR28 data. [C-11]-L-deprenyl-D2 was quantified using lambda k(3). PET imaging metrics were compared across groups, and when differing across groups, against clinical variables. Compared to HC, FM patients demonstrated widespread cortical elevations, and no decreases, in [C-11]PBR28 ITT and SUVR, most pronounced in the medial and lateral walls of the frontal and parietal lobes. No regions showed significant group differences in [C-11]-L-deprenyl-Ds signal, including those demonstrating elevated [C-11] PBR28 signal in patients (p's >= 0.53, uncorrected). The elevations in [C-11]PBR28 V-T and SUVR were correlated both spatially (i.e., were observed in overlapping regions) and, in several areas, also in terms of magnitude. In exploratory, uncorrected analyses, higher subjective ratings of fatigue in FM patients were associated with higher [C-11] PBR28 SUVR in the anterior and posterior middle cingulate cortices (p's < 0.03). SUVR was not significantly associated with any other clinical variable. Our work provides the first in vivo evidence supporting a role for glial activation in FM pathophysiology. Given that the elevations in [C-11]PBR28 signal were not also accompanied by increased [C-11]-deprenyl-D2 signal, our data suggests that microglia, but not astrocytes, may be driving the TSPO elevation in these regions. Although [C-11]-L-deprenyl-D2 signal was not found to be increased in FM patients, larger studies are needed to further assess the role of possible astrocytic contributions in FM. Overall, our data support glial modulation as a potential therapeutic strategy for FM.
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| 3. |
- Emami Khoonsari, Payam, et al.
(författare)
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The human CSF pain proteome
- 2019
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Ingår i: Journal of Proteomics. - : ELSEVIER SCIENCE BV. - 1874-3919 .- 1876-7737. ; 190, s. 67-76
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Tidskriftsartikel (refereegranskat)abstract
- Chronic pain represents one of the major medical challenges in the 21st century, affecting > 1.5 billion of the world population. Overlapping and heterogenous symptoms of various chronic pain conditions complicate their diagnosis, emphasizing the need for more specific biomarkers to improve the diagnosis and understand the disease mechanisms. We have here investigated proteins found in human CSF with respect to known "pain" genes and in a cohort of patients with dysfunctional pain (fibromyalgia, FM), inflammatory pain (rheumatoid arthritis patients, RA) and non-pain controls utilized semi-quantitative proteomics using mass spectrometry (MS) to explore quantitative differences between these cohorts of patients. We found that "pain proteins" detected in CSF using MS are typically related to synaptic transmission, inflammatory responses, neuropeptide signaling- and hormonal activity. In addition, we found ten proteins potentially associated with chronic pain in FM and RA: neural cell adhesion molecule L1, complement C4-A, lysozyme C, receptor-type tyrosine-protein phosphatase zeta, apolipoprotein D, alpha-1-antichymotrypsin, granulins, calcium/calmodulin-dependent protein kinase type II subunit alpha, mast/stem cell growth factor receptor Kit, prolow-density lipoprotein receptor-related protein 1. These proteins might be of importance for understanding the mechanisms of dysfunctional/inflammatory chronic pain and also for use as potential biomarkers. Significance: Chronic pain is a common disease and it poses a large burden on worldwide health. Fibromyalgia (FM) is a heterogeneous disease of unknown etiology characterized by chronic widespread pain (CWP). The diagnosis and treatment of FM is based on the analysis of clinical assessments and no measurable biomarkers are available. Cerebrospinal fluid (CSF) has been historically considered as a rich source of biomarkers for diseases of nervous system including chronic pain. Here, we explore CSF proteome of FM patients utilizing mass spectrometry based quantitative proteomics method combined with multivariate data analysis in order to monitor the dynamics of the CSF proteome. Our findings in this exploratory study support notable presence of pain related proteins in CSF yet with specific domains including inflammatory responses, neuropeptide signaling- and hormonal activity. We have investigated molecular functions of significantly altered proteins and demonstrate presence of 176 known pain related proteins in CSF. In addition, we found ten proteins potentially associated with pain in FM and RA: neural cell adhesion molecule L1, complement C4-A, lysozyme C, receptor-type tyrosine-protein phosphatase zeta, apolipoprotein D, alpha-1-antichymotrypsin, granulins, calcium/calmodulindependent protein kinase type II subunit alpha, mast/stem cell growth factor receptor Kit, prolow-density lipoprotein receptor-related protein 1. These proteins are novel in the context of FM but are known to be involved in pain mechanisms including inflammatory response and signal transduction. These results should be of clear significance and interest for researchers and clinicians working in the field of pain utilizing human CSF and MS based proteomics.
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| 4. |
- Flodin, Pär, et al.
(författare)
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Intrinsic Brain Connectivity in Chronic Pain : A Resting-State fMRI Study in Patients with Rheumatoid Arthritis.
- 2016
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Ingår i: Frontiers in Human Neuroscience. - : Frontiers Media SA. - 1662-5161. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Rheumatoid arthritis (RA) is commonly accompanied by pain that is discordant with the degree of peripheral pathology. Very little is known about the cerebral processes involved in pain processing in RA. Here we investigated resting-state brain connectivity associated with prolonged pain in RA.METHODS: 24 RA subjects and 19 matched controls were compared with regard to both behavioral measures of pain perception and resting-resting state fMRI data acquired subsequently to fMRI sessions involving pain stimuli. The resting-state fMRI brain connectivity was investigated using 159 seed regions located in cardinal pain processing brain regions. Additional principal component based multivariate pattern analysis of the whole brain connectivity pattern was carried out in a data driven analysis to localize group differences in functional connectivity.RESULTS: When RA patients were compared to controls, we observed significantly lower pain resilience for pressure on the affected finger joints (i.e., P50-joint) and an overall heightened level of perceived global pain in RA patients. Relative to controls, RA patients displayed increased brain connectivity predominately for the supplementary motor areas, mid-cingulate cortex, and the primary sensorimotor cortex. Additionally, we observed an increase in brain connectivity between the insula and prefrontal cortex as well as between anterior cingulate cortex and occipital areas for RA patients. None of the group differences in brain connectivity were significantly correlated with behavioral parameters.CONCLUSION: Our study provides experimental evidence of increased connectivity between frontal midline regions that are implicated in affective pain processing and bilateral sensorimotor regions in RA patients.
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| 5. |
- Kanegawa, Naoki, et al.
(författare)
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In vivo evidence of a functional association between immune cells in blood and brain in healthy human subjects
- 2016
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Ingår i: Brain, behavior, and immunity. - : ACADEMIC PRESS INC ELSEVIER SCIENCE. - 0889-1591 .- 1090-2139. ; 54, s. 149-157
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Tidskriftsartikel (refereegranskat)abstract
- Microglia, the resident macrophages in the central nervous system, are thought to be maintained by a local self-renewal mechanism. Although preclinical and in vitro studies have suggested that the brain may contain immune cells also from peripheral origin, the functional association between immune cells in the periphery and brain at physiological conditions is poorly understood. We examined 32 healthy individuals using positron emission tomography (PET) and [C-11]PBR28, a radioligand for the 18-kDa translocator protein (TSPO) which is expressed both in brain microglia and blood immune cells. In 26 individuals, two measurements were performed with varying time intervals. In a subgroup of 19 individuals, of which 12 had repeat examinations, leukocyte numbers in blood was measured on each day of PET measurements. All individuals were genotyped for TSPO polymorphism and categorized as high, mixed, and low affinity binders. We assessed TSPO binding expressed as total distribution volume of [C-11]PBR28 in brain and in blood cells. TSPO binding in brain was strongly and positively correlated to binding in blood cells both at baseline and when analyzing change between two PET examinations. Furthermore, there was a significant correlation between change of leukocyte numbers and change in TSPO binding in brain, and a trend level correlation to change in TSPO binding in blood cells. These in vivo findings indicate an association between immunological cells in blood and brain via intact BBB, suggesting a functional interaction between these two compartments, such as interchange of peripherally derived cells or a common regulatory mechanism. Measurement of radioligand binding in blood cells may be a way to control for peripheral immune function in PET studies using TSPO as a marker of brain immune activation. (C) 2016 Elsevier Inc. All rights reserved.
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| 6. |
- Kosek, Eva, et al.
(författare)
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Evidence of different mediators of central inflammation in dysfunctional and inflammatory pain--interleukin-8 in fibromyalgia and interleukin-1 β in rheumatoid arthritis.
- 2015
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Ingår i: Journal of Neuroimmunology. - : Elsevier BV. - 0165-5728 .- 1872-8421. ; 280, s. 49-55
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to relate central inflammation to autonomic activity (heart rate variability (HRV)) in patients with rheumatoid arthritis (RA) and fibromyalgia (FM). RA patients had reduced parasympathetic activity and FM patients had increased sympathetic activity compared to healthy controls. Comparisons between RA and FM showed higher cerebrospinal fluid (CSF) interleukin (IL)-1β inversely correlated to parasympathetic activity in RA. The FM patients had higher concentrations of CSF IL-8, IL-1Ra, IL-4 and IL-10, but none of these cytokines correlated with HRV. In conclusion, we found different profiles of central cytokines, i.e., elevated IL-1β in inflammatory pain (RA) and elevated IL-8 in dysfunctional pain (FM).
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| 7. |
- Lourdudoss, Cecilia, et al.
(författare)
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Dietary Intake of Polyunsaturated Fatty Acids and Pain in Spite of Inflammatory Control Among Methotrexate-Treated Early Rheumatoid Arthritis Patients.
- 2018
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Ingår i: Arthritis care & research. - : Wiley. - 2151-464X .- 2151-4658. ; 70:2, s. 205-212
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To investigate potential associations between dietary intake of polyunsaturated fatty acids (FAs) and pain patterns in early rheumatoid arthritis (RA) patients after 3 months of methotrexate (MTX) treatment.METHODS: We included 591 early RA patients with MTX monotherapy from a population-based prospective case-control study, the Epidemiological Investigation of Rheumatoid Arthritis. Dietary data on polyunsaturated FAs (food frequency questionnaires) were linked with data on unacceptable pain (visual analog scale [VAS] >40 mm), noninflammatory/refractory pain (VAS >40 mm and C-reactive protein [CRP] level <10 mg/liter), and inflammatory pain (VAS >40 mm and CRP level >10 mg/liter) after 3 months. Statistical analysis included logistic regression.RESULTS: After 3 months of MTX treatment, 125 patients (21.2%) had unacceptable pain, of which 92 patients had refractory pain, and 33 patients had inflammatory pain. Omega-3 FA intake was inversely associated with unacceptable pain and refractory pain (odds ratio [OR] 0.57 [95% confidence interval (95% CI) 0.35-0.95] and OR 0.47 [95% CI 0.26-0.84], respectively). The omega-6:omega-3 FA ratio, but not omega-6 FA alone, was directly associated with unacceptable pain and refractory pain (OR 1.70 [95% CI 1.03-2.82] and OR 2.33 [95% CI 1.28-4.24], respectively). Furthermore, polyunsaturated FAs were not associated with either inflammatory pain or CRP level and erythrocyte sedimentation rate at followup. Omega-3 FA supplementation was not associated with any pain patterns.CONCLUSION: Omega-3 FA was inversely associated with, and the omega-6:omega-3 FA ratio was directly associated with, unacceptable and refractory pain, but not with inflammatory pain or systemic inflammation. The inverse association between omega-3 FA and refractory pain may have a role in pain suppression in RA.
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| 8. |
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| 9. |
- Plaven-Sigray, Pontus, et al.
(författare)
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Accuracy and reliability of [C-11]PBR28 specific binding estimated without the use of a reference region
- 2019
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Ingår i: NeuroImage. - : ACADEMIC PRESS INC ELSEVIER SCIENCE. - 1053-8119 .- 1095-9572. ; 188, s. 102-110
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Tidskriftsartikel (refereegranskat)abstract
- [C-11]PBR28 is a positron emission tomography radioligand used to examine the expression of the 18 kDa translocator protein (TSPO). TSPO is located in glial cells and can function as a marker for immune activation. Since TSPO is expressed throughout the brain, no true reference region exists. For this reason, an arterial input function is required for accurate quantification of [C-11]PBR28 binding and the most common outcome measure is the total distribution volume (V-T). Notably, V-T reflects both specific binding and non-displaceable binding. Therefore, estimates of specific binding, such as binding potential (e.g. BPND) and specific distribution volume (V-S) should theoretically be more sensitive to underlying differences in TSPO expression. It is unknown, however, if unbiased and accurate estimates of these outcome measures are obtainable for [C-11]PBR28. The Simultaneous Estimation (SIME) method uses time-activity-curves from multiple brain regions with the aim to obtain a brain-wide estimate of the non-displaceable distribution volume (V-ND), which can subsequently be used to improve the estimation of BPND and V-S. In this study we evaluated the accuracy of SIME-derived V-ND, and the reliability of resulting estimates of specific binding for [C-11]PBR28, using a combination of simulation experiments and in vivo studies in healthy humans. The simulation experiments, based on data from 54 unique [C-11]PBR28 examinations, showed that V-ND values estimated using SIME were both precise and accurate. Data from a pharmacological competition challenge (n = 5) showed that SIME provided V-ND values that were on average 19% lower than those obtained using the Lassen plot, but similar to values obtained using the Likelihood-Estimation of Occupancy technique. Test-retest data (n = 11) showed that SIME-derived V-S values exhibited good reliability and precision, while larger variability was observed in SIME-derived BPND values. The results support the use of SIME for quantifying specific binding of [C-11]PBR28, and suggest that V-S can be used in complement to the conventional outcome measure V-T. Additional studies in patient cohorts are warranted.
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| 10. |
- Tamm, Sandra, et al.
(författare)
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Evidence of fatigue, disordered sleep and peripheral inflammation, but not increased brain TSPO expression, in seasonal allergy : A [11C]PBR28 PET study
- 2018
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Ingår i: Brain, behavior, and immunity. - : Elsevier BV. - 0889-1591 .- 1090-2139. ; 68, s. 146-157
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Tidskriftsartikel (refereegranskat)abstract
- Allergy is associated with non-specific symptoms such as fatigue, sleep problems and impaired cognition. One explanation could be that the allergic inflammatory state includes activation of immune cells in the brain, but this hypothesis has not been tested in humans. The aim of the present study was therefore to investigate seasonal changes in the glial cell marker translocator protein (TSPO), and to relate this to peripheral inflammation, fatigue and sleep, in allergy. We examined 18 patients with severe seasonal allergy, and 13 healthy subjects in and out-of pollen season using positron emission tomography (n = 15/13) and the TSPO radioligand [11C]PBR28. In addition, TNF-α, IL-5, IL-6, IL-8 and IFN-γ were measured in peripheral blood, and subjective ratings of fatigue and sleepiness as well as objective and subjective sleep were investigated. No difference in levels of TSPO was seen between patients and healthy subjects, nor in relation to pollen season. However, allergic subjects displayed both increased fatigue, sleepiness and increased percentage of deep sleep, as well as increased levels of IL-5 and TNF-α during pollen season, compared to healthy subjects. Allergic subjects also had shorter total sleep time, regardless of season. In conclusion, allergic subjects are indicated to respond to allergen exposure during pollen season with a clear pattern of behavioral disruption and peripheral inflammatory activation, but not with changes in brain TSPO levels. This underscores a need for development and use of more specific markers to understand brain consequences of peripheral inflammation that will be applicable in human subjects.
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