| 1. |
- Smeets, F. G. M., et al.
(författare)
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Development of a real-time patient-reported outcome measure for symptom assessment in patients with functional dyspepsia using the experience sampling method
- 2019
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Ingår i: Neurogastroenterology and Motility. - : Wiley. - 1350-1925 .- 1365-2982. ; 31:2
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Tidskriftsartikel (refereegranskat)abstract
- Background Patient-reported outcome measures (PROMs) are used to assess symptoms in patients with functional dyspepsia (FD). Current end-of-day questionnaires have several limitations including sensitivity to recall and ecological bias. The experience sampling method (ESM) is characterized by random and repeated assessments across momentary states in daily life and therefore less sensitive to these limitations. This study describes the development of a novel PROM based on ESM technology. Methods An initial draft of the PROM was developed based on literature. Focus group interviews with FD patients according to Rome IV criteria, and an expert meeting with international opinion leaders in the field of functional gastrointestinal disorders were conducted in order to select items for the PROM. Cognitive interviews were performed to evaluate patients' understanding of the selected items and to create the definitive PROM. Key results A systematic literature search revealed 59 items across four domains (ie, physical status; mood and psychological factors; context and environment; and nutrition, medication, and substance use). After patient focus group interviews and an international expert meeting, the number of items was reduced to 33. Cognitive interviews resulted in some minor linguistic changes in order to improve patients' understanding. Conclusions and inferences A novel digital ESM-based PROM for real-time symptom assessment in patients with functional dyspepsia was developed. This novel PROM has the potential to identify individual symptom patterns and specific triggers for dyspeptic symptoms, and optimize treatment strategies.
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| 2. |
- Keller, J., et al.
(författare)
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Advances in the diagnosis and classification of gastric and intestinal motility disorders
- 2018
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Ingår i: Nature Reviews Gastroenterology & Hepatology. - : Springer Science and Business Media LLC. - 1759-5045 .- 1759-5053. ; 15:5, s. 291-308
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Tidskriftsartikel (refereegranskat)abstract
- Disturbances of gastric, intestinal and colonic motor and sensory functions affect a large proportion of the population worldwide, impair quality of life and cause considerable health-care costs. Assessment of gastrointestinal motility in these patients can serve to establish diagnosis and to guide therapy. Major advances in diagnostic techniques during the past 5-10 years have led to this update about indications for and selection and performance of currently available tests. As symptoms have poor concordance with gastrointestinal motor dysfunction, clinical motility testing is indicated in patients in whom there is no evidence of causative mucosal or structural diseases such as inflammatory or malignant disease. Transit tests using radiopaque markers, scintigraphy, breath tests and wireless motility capsules are noninvasive. Other tests of gastrointestinal contractility or sensation usually require intubation, typically represent second-line investigations limited to patients with severe symptoms and are performed at only specialized centres. This Consensus Statement details recommended tests as well as useful clinical alternatives for investigation of gastric, small bowel and colonic motility. The article provides recommendations on how to classify gastrointestinal motor disorders on the basis of test results and describes how test results guide treatment decisions.
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| 3. |
- Moreira, Xoaquín, et al.
(författare)
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Impacts of urbanization on insect herbivory and plant defences in oak trees
- 2019
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Ingår i: Oikos. - : Wiley. - 0030-1299 .- 1600-0706. ; 128:1, s. 113-123
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Tidskriftsartikel (refereegranskat)abstract
- Systematic comparisons of species interactions in urban versus rural environments can improve our understanding of shifts in ecological processes due to urbanization. However, such studies are relatively uncommon and the mechanisms driving urbanization effects on species interactions (e.g. between plants and insect herbivores) remain elusive. Here we investigated the effects of urbanization on leaf herbivory by insect chewers and miners associated with the English oak Quercus robur by sampling trees in rural and urban areas throughout most of the latitudinal distribution of this species. In performing these comparisons, we also controlled for the size of the urban areas (18 cities) and gathered data on CO2 emissions. In addition, we assessed whether urbanization affected leaf chemical defences (phenolic compounds) and nutritional traits (phosphorus and nitrogen), and whether such changes correlated with herbivory levels. Urbanization significantly reduced leaf chewer damage but did not affect leaf miners. In addition, we found that leaves from urban locations had lower levels of chemical defences (condensed and hydrolysable tannins) and higher levels of nutrients (nitrogen and phosphorus) compared to leaves in rural locations. The magnitude of urbanization effects on herbivory and leaf defences was not contingent upon city size. Importantly, while the effects of urbanization on chemical defences were associated with CO2 emissions, changes in leaf chewer damage were not associated with either leaf traits or CO2 levels. These results suggest that effects of urbanization on herbivory occur through mechanisms other than changes in the plant traits measured here. Overall, our simultaneous assessment of insect herbivory, plant traits and abiotic correlates advances our understanding of the main drivers of urbanization effects on plant-herbivore interactions.
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| 4. |
- Pauwels, A, et al.
(författare)
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How to select patients for antireflux surgery? The ICARUS guidelines (international consensus regarding preoperative examinations and clinical characteristics assessment to select adult patients for antireflux surgery)
- 2019
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Ingår i: Gut. - : BMJ. - 1468-3288 .- 0017-5749. ; 68:11, s. 1928-1941
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Tidskriftsartikel (refereegranskat)abstract
- Antireflux surgery can be proposed in patients with GORD, especially when proton pump inhibitor (PPI) use leads to incomplete symptom improvement. However, to date, international consensus guidelines on the clinical criteria and additional technical examinations used in patient selection for antireflux surgery are lacking. We aimed at generating key recommendations in the selection of patients for antireflux surgery.DesignWe included 35 international experts (gastroenterologists, surgeons and physiologists) in a Delphi process and developed 37 statements that were revised by the Consensus Group, to start the Delphi process. Three voting rounds followed where each statement was presented with the evidence summary. The panel indicated the degree of agreement for the statement. When 80% of the Consensus Group agreed (A+/A) with a statement, this was defined as consensus. All votes were mutually anonymous.ResultsPatients with heartburn with a satisfactory response to PPIs, patients with a hiatal hernia (HH), patients with oesophagitis Los Angeles (LA) grade B or higher and patients with Barrett’s oesophagus are good candidates for antireflux surgery. An endoscopy prior to antireflux surgery is mandatory and a barium swallow should be performed in patients with suspicion of a HH or short oesophagus. Oesophageal manometry is mandatory to rule out major motility disorders. Finally, oesophageal pH (±impedance) monitoring of PPI is mandatory to select patients for antireflux surgery, if endoscopy is negative for unequivocal reflux oesophagitis.ConclusionWith the ICARUS guidelines, we generated key recommendations for selection of patients for antireflux surgery.
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| 5. |
- Vork, L., et al.
(författare)
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Development, content validity, and cross-cultural adaptation of a patient-reported outcome measure for real-time symptom assessment in irritable bowel syndrome
- 2018
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Ingår i: Neurogastroenterology and Motility. - : Wiley. - 1350-1925. ; 30:3
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundEnd-of-day questionnaires, which are considered the gold standard for assessing abdominal pain and other gastrointestinal (GI) symptoms in irritable bowel syndrome (IBS), are influenced by recall and ecological bias. The experience sampling method (ESM) is characterized by random and repeated assessments in the natural state and environment of a subject, and herewith overcomes these limitations. This report describes the development of a patient-reported outcome measure (PROM) based on the ESM principle, taking into account content validity and cross-cultural adaptation. MethodsFocus group interviews with IBS patients and expert meetings with international experts in the fields of neurogastroenterology & motility and pain were performed in order to select the items for the PROM. Forward-and-back translation and cognitive interviews were performed to adapt the instrument for the use in different countries and to assure on patients' understanding with the final items. Key resultsFocus group interviews revealed 42 items, categorized into five domains: physical status, defecation, mood and psychological factors, context and environment, and nutrition and drug use. Experts reduced the number of items to 32 and cognitive interviewing after translation resulted in a few slight adjustments regarding linguistic issues, but not regarding content of the items. Conclusions and InferencesAn ESM-based PROM, suitable for momentary assessment of IBS symptom patterns was developed, taking into account content validity and cross-cultural adaptation. This PROM will be implemented in a specifically designed smartphone application and further validation in a multicenter setting will follow.
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| 6. |
- Enck, P, et al.
(författare)
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Functional dyspepsia
- 2017
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Ingår i: Nature reviews. Disease primers. - : Springer Science and Business Media LLC. - 2056-676X. ; 3, s. 17081-
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Tidskriftsartikel (refereegranskat)
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| 7. |
- Tack, Ayco J. M., et al.
(författare)
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Below-ground abiotic and biotic heterogeneity shapes above-ground infection outcomes and spatial divergence in a host-parasite interaction
- 2015
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Ingår i: New Phytologist. - : Wiley. - 0028-646X .- 1469-8137. ; 207:4, s. 1159-1169
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Tidskriftsartikel (refereegranskat)abstract
- We investigated the impact of below-ground and above-ground environmental heterogeneity on the ecology and evolution of a natural plant-pathogen interaction. We combined field measurements and a reciprocal inoculation experiment to investigate the potential for natural variation in abiotic and biotic factors to mediate infection outcomes in the association between the fungal pathogen Melampsora lini and its wild flax host, Linum marginale, where pathogen strains and plant lines originated from two ecologically distinct habitat types that occur in close proximity (bog' and hill'). The two habitat types differed strikingly in soil moisture and soil microbiota. Infection outcomes for different host-pathogen combinations were strongly affected by the habitat of origin of the plant lines and pathogen strains, the soil environment and their interactions. Our results suggested that tradeoffs play a key role in explaining the evolutionary divergence in interaction traits among the two habitat types. Overall, we demonstrate that soil heterogeneity, by mediating infection outcomes and evolutionary divergence, can contribute to the maintenance of variation in resistance and pathogenicity within a natural host-pathogen metapopulation.
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| 8. |
- Tack, J., et al.
(författare)
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An expert consensus definition of failure of a treatment to provide adequate relief (F-PAR) for chronic constipation - an international Delphi survey
- 2017
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Ingår i: Alimentary Pharmacology & Therapeutics. - : Wiley. - 0269-2813. ; 45:3, s. 434-442
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Tidskriftsartikel (refereegranskat)abstract
- Background As treatments for constipation become increasingly available, it is important to know when to progress along the treatment algorithm if the patient is not better. To establish the definition of failure of a treatment to provide adequate relief (F-PAR) to support this management and referral process in patients with chronic constipation. We conducted an international Delphi Survey among gastroenterologists and general practitioners with a special interest in chronic constipation. An initial questionnaire based on recognised rating scales was developed following a focus group. Data were collected from two subsequent rounds of questionnaires completed by all authors. Likert scales were used to establish a consensus on a shorter list of more severe symptoms. The initial focus group yielded a first round questionnaire with 84 statements. There was good consensus on symptom severity and a clear severity response curve, allowing 67 of the symptom-severity pairings to be eliminated. Subsequently, a clear consensus was established on further reduction to eight symptom statements in the final definition, condensed by the steering committee into five diagnostic statements (after replicate statements had been removed). We present an international consensus on chronic constipation, of five symptoms and their severities, any of which would be sufficient to provide clinical evidence of treatment failure. We also provide data representing an expert calibration of commonly used rating scales, thus allowing results of clinical trials expressed in terms of those scales to be converted into estimates of rates of provision of adequate relief.
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| 9. |
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| 10. |
- Tack, J., et al.
(författare)
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Long-term safety and efficacy of acotiamide in functional dyspepsia (postprandial distress syndrome)results from the European phase 3 open-label safety trial
- 2018
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Ingår i: Neurogastroenterology and Motility. - : Wiley. - 1350-1925. ; 30:6
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundsAcotiamide is a novel acetylcholinesterase inhibitor for treatment of postprandial distress syndrome (PDS) symptoms of functional dyspepsia (FD). This European phase 3 open-label safety trial has been conducted to evaluate the long-term safety of acotiamide and explore the efficacy of acotiamide on PDS symptoms using the validated LPDS, quality of life using SF-36 and SF-NDI, and work productivity using WPAI. MethodsFD-PDS patients (defined by ROME III criteria) aged 18years with active PDS symptoms and without predominant overlapping symptoms of epigastric pain syndrome and related disorders were enrolled to receive 100mg acotiamide three times daily for 1year. Patients' safety profile and efficacy of acotiamide were monitored. Key ResultsThe majority of patients (81.6%) maintained exposure to acotiamide for >50weeks, with a mean duration of 320.3days. No specific clinically significant safety concerns have been shown, with no deaths, treatment-related severe/serious adverse events, or any clinically significant laboratory test results. Although being an open-label trial, acotiamide showed a change in severity larger than the minimum clinically important difference at weeks 1 and 2 for postprandial fullness and early satiation (meal-related symptoms), and showed improvement of quality of life and work productivity from the first measurement (at week 12) up to 1year. Conclusions & InferencesThe long-term safety of acotiamide treatment was confirmed. A clinically important change for PDS symptoms, QoL, and work productivity was suggested; however a controlled trial is required to confirm this hypothetic efficacy of acotiamide. (NCT01973790).
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| 11. |
- Tack, J., et al.
(författare)
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Plausibility criteria for putative pathophysiological mechanisms in functional gastrointestinal disorders: a consensus of experts
- 2018
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Ingår i: Gut. - : BMJ. - 0017-5749 .- 1468-3288. ; 67:8, s. 1425-1433
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Tidskriftsartikel (refereegranskat)abstract
- Background and aims The functional gastrointestinal disorders (FGIDs) are extremely common conditions associated with a considerable personal, social and health economic burden. Managing FGIDs in clinical practice is challenging because of the uncertainty of symptom-based diagnosis, the high frequency of overlap between these conditions and the limited efficacy of available therapies. It has often been argued that successful drug development and management of FGIDs requires knowledge of the underlying pathophysiology. Numerous and highly variable candidate pathophysiological mechanisms have been implicated in the generation of FGID symptoms, but there is no current consensus on how to best define the relevance of these disturbances. Methods A group of international experts on FGIDs developed plausibility criteria that should be fulfilled by relevant pathophysiological mechanisms in FGIDs. Results Five criteria are proposed: (1) the presence of the abnormality in a subset of patients, (2) temporal association between proposed mechanism and symptom(s), (3) correlation between the level of impairment of the mechanism and symptom(s), (4) induction of the symptom(s) by provoking the pathophysiological abnormality in healthy subjects and (5) treatment response by a therapy specifically correcting the underlying disorder or congruent natural history of symptoms and dysfunction in the absence of specific therapy. Based on strength of evidence for these five criteria according to the Grading of Recommendations Assessment, Development and Evaluation system, a plausibility score can be calculated for each mechanism. Conclusion Evaluation of the strength of evidence for candidate pathophysiological abnormalities fulfilling these five plausibility criteria will help to identify the most relevant mechanisms to target for novel diagnostic approaches and for the development of new therapies.
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| 12. |
- Amadini, Roberto, et al.
(författare)
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MiniZinc with strings
- 2017
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Ingår i: Logic-Based Program Synthesis and Transformation. - Cham : Springer. - 9783319631387 - 9783319631394 ; , s. 59-75
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Konferensbidrag (refereegranskat)abstract
- Strings are extensively used in modern programming languages and constraints over strings of unknown length occur in a wide range of real-world applications such as software analysis and verification, testing, model checking, and web security. Nevertheless, practically no constraint programming solver natively supports string constraints. We introduce string variables and a suitable set of string constraints as builtin features of the MiniZinc modelling language. Furthermore, we define an interpreter for converting a MiniZinc model with strings into a FlatZinc instance relying only on integer variables. This conversion is obtained via rewrite rules, and does not require any extension of the existing FlatZinc specification. This provides a user-friendly interface for modelling combinatorial problems with strings, and enables both string and non-string solvers to actually solve such problems.
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| 13. |
- Björdal, Gustav, et al.
(författare)
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Declarative local-search neighbourhoods in MiniZinc
- 2018
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Ingår i: PROCEEDINGS OF THE 2018 IEEE 30TH INTERNATIONAL CONFERENCE ON TOOLS WITH ARTIFICIAL INTELLIGENCE (ICTAI). - : IEEE Computer Society. - 9781538674499 ; , s. 98-105
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Konferensbidrag (refereegranskat)abstract
- The aim of solver-independent modelling is to create a model of a satisfaction or optimisation problem independent of a particular technology. This avoids early commitment to a solving technology and allows easy comparison of technologies. MiniZinc is a solver-independent modelling language, supported by CP, MIP, SAT, SMT, and constraint-based local search (CBLS) backends. Some technologies, in particular CP and CBLS, require not only a model but also a search strategy. While backends for these technologies offer default search strategies, it is often beneficial to include in a model a user-specified search strategy for a particular technology, especially if the strategy can encapsulate knowledge about the problem structure. This is complex since a local-search strategy (comprising a neighbourhood, a heuristic, and a meta-heuristic) is often tightly tied to the model. Hence we wish to use the same language for specifying the model and the local search. We show how to extend MiniZinc so that one can attach a fully declarative neighbourhood specification to a model, while maintaining the solver-independence of the language. We explain how to integrate a model-specific declarative neighbourhood with an existing CBLS backend for MiniZinc.
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| 14. |
- Blanchet, F. Guillaume, et al.
(författare)
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Related herbivore species show similar temporal dynamics
- 2018
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Ingår i: Journal of Animal Ecology. - : Wiley. - 0021-8790 .- 1365-2656. ; 87:3, s. 801-812
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Tidskriftsartikel (refereegranskat)abstract
- 1. Within natural communities, different taxa display different dynamics in time. Why this is the case we do not fully know. This thwarts our ability to predict changes in community structure, which is important for both the conservation of rare species in natural communities and for the prediction of pest outbreaks in agriculture. 2. Species sharing phylogeny, natural enemies and/or life-history traits have been hypothesized to share similar temporal dynamics. We operationalized these concepts into testing whether feeding guild, voltinism, similarity in parasitoid community and/or phylogenetic relatedness explained similarities in temporal dynamics among herbivorous community members. 3. Focusing on two similar datasets from different geographical regions (Finland and Japan), we used asymmetric eigenvector maps as temporal variables to characterize species-and community-level dynamics of specialist insect herbivores on oak (Quercus). We then assessed whether feeding guild, voltinism, similarity in parasitoid community and/or phylogenetic relatedness explained similarities in temporal dynamics among taxa. 4. Species-specific temporal dynamics varied widely, ranging from directional decline or increase to more complex patterns. Phylogeny was a clear predictor of similarity in temporal dynamics at the Finnish site, whereas for the Japanese site, the data were uninformative regarding a phylogenetic imprint. Voltinism, feeding guild and parasitoid overlap explained little variation at either location. Despite the rapid temporal dynamics observed at the level of individual species, these changes did not translate into any consistent temporal changes at the community level in either Finland or Japan. 5. Overall, our findings offer no direct support for the notion that species sharing natural enemies and/or life-history traits would be characterized by similar temporal dynamics, but reveal a strong imprint of phylogenetic relatedness. As this phylogenetic signal cannot be attributed to guild, voltinism or parasitoids, it will likely derive from shared microhabitat, microclimate, anatomy, physiology or behaviour. This has important implications for predicting insect outbreaks and for informing insect conservation. We hope that future studies will assess the generality of our findings across plant-feeding insect communities and beyond, and establish the more precise mechanism(s) underlying the phylogenetic imprint.
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| 15. |
- Clevers, Egbert, et al.
(författare)
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Development of Irritable Bowel Syndrome Features Over a 5-year Period
- 2018
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Ingår i: Clinical Gastroenterology and Hepatology. - : Elsevier BV. - 1542-3565. ; 16:8
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND & AIMS: There are few data from longitudinal studies of the gastrointestinal and psychologic features of irritable bowel syndrome (IBS). We studied within-person correlations among features of IBS, along with progression of gastrointestinal (GI) symptoms and quality of life, and factors associated with changes over time. METHODS: We performed a longitudinal study of 276 patients with IBS in Sweden (70% female; ages, 19-76 years) who completed questionnaires, each year for 5 years, about their GI symptom severity, quality of life, GI-specific anxiety, general anxiety, depression, and coping resources. We performed within-person correlation analyses, latent class growth analysis, and random-intercept cross-lagged panel analysis. RESULTS: Within-person correlations with GI symptom severity were strongest for quality of life (r = -0.56) and GI-specific anxiety (r = 0.47). Progression of GI symptom severity was defined based on 3 classes; the class with the highest mean levels of GI, depression, and (GI-specific) anxiety symptoms at baseline did not improve over the 5-year period, contrary to the other classes. GI-specific anxiety was associated with an increase in GI symptom severity and decrease in quality of life 1 year later (P < .05) but other features of IBS were not. CONCLUSIONS: In a 5-year study of patients with IBS in Sweden, we found 3 classes of GI symptom development. We found levels of GI-specific anxiety to associate with GI symptom severity and quality of life 1 year later. Clinicians should be aware of GI-specific anxiety in patients with IBS, to identify patients at risk for lack of long-term symptom improvement with standard medical treatment.
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| 16. |
- Clevers, Egbert, et al.
(författare)
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Factor Analysis Defines Distinct Upper and Lower Gastrointestinal Symptom Groups Compatible With Rome IV Criteria in a Population-based Study
- 2018
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Ingår i: Clinical Gastroenterology and Hepatology. - : Elsevier BV. - 1542-3565. ; 16:8
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND & AIMS: The Rome IV criteria define functional gastrointestinal (GI) disorders by specific combinations of symptoms. It is possible to empirically evaluate these symptom combinations by factor analysis (a statistical procedure that groups variables that correlate). However, this analysis has not been performed for the Rome IV criteria, and factor analyses based on the previous versions of the Rome criteria did not use population-based data. We therefore investigated symptom grouping by the Rome IV questionnaire using factor analysis of a population-based sample. METHODS: The Rome IV questionnaire was completed online in English by 5931 respondents from the United Kingdom, United States, and Canada (49% female, age range, 18-92 years). We performed an exploratory factor analysis on the Rome IV questions. Next, we performed a confirmatory factor analysis to compare the exploratory factor result to that of the Rome IV criteria. RESULTS: The exploratory factor analysis identified 8 factors that accounted for 45% of the variance in response: constipation, diarrhea, irritable bowel syndrome, abdominal pain, heartburn, nausea or vomiting, globus, and other upper GI symptoms. Most factors corresponded to distinct functional GI disorders defined by the Rome IV criteria-exceptions included abdominal pain and upper GI symptoms. In confirmatory factor analysis, the exploratory model fitted slightly better than that based on the Rome IV criteria (root mean square error of approximation, 0.063 vs 0.077). CONCLUSIONS: We used factor analysis to identify distinct upper and lower GI symptom groups that are compatible with the Rome IV criteria. Our findings support the use of the Rome IV criteria in research and clinical practice as a basis for development of diagnostics and management of patients.
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| 17. |
- Clevers, Egbert, et al.
(författare)
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Health problems associated with irritable bowel syndrome: analysis of a primary care registry
- 2018
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Ingår i: Alimentary Pharmacology & Therapeutics. - : Wiley. - 0269-2813. ; 47:10, s. 1349-1357
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Tidskriftsartikel (refereegranskat)abstract
- Background: Associations between irritable bowel syndrome and other health problems have been described, but comprehensive reports are missing, especially in primary care. Aims: To investigate which health problems are associated with irritable bowel syndrome, how they cluster together and when they are typically diagnosed relative to irritable bowel syndrome. Methods: We used Intego, a general practice registry in Flanders, Belgium. Patients with an irritable bowel syndrome diagnosis (n=13701) were matched with controls without gastrointestinal diagnosis and controls with organic gastrointestinal disease. Long-term prevalences of 680 symptoms and diagnoses were compared between patients and controls. Results were summarised using functional enrichment analysis and visualised in a network and we calculated incidence rate ratios in the 10 years before and after the irritable bowel syndrome diagnosis for the network's key components. Results: Various symptoms and infections, but not neoplasms, were enriched in irritable bowel syndrome patients compared to both control groups. We characterised the comorbidities of irritable bowel syndrome as psychosocial health problems, urogenital symptoms and infections, musculoskeletal symptoms and other somatic symptoms. These had a uniform incidence in the years around the irritable bowel syndrome diagnosis, and did not structurally precede or follow irritable bowel syndrome. Conclusions: Irritable bowel syndrome shares long-term associations with psychosocial health problems, urogenital symptoms and infections, musculoskeletal symptoms and other somatic symptoms in primary care. Clinicians are encouraged to take comorbidities into account when diagnosing and managing irritable bowel syndrome, as this may have important treatment implications.
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| 18. |
- Clevers, Egbert, et al.
(författare)
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Relations between food intake, psychological distress, and gastrointestinal symptoms: A diary study
- 2019
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Ingår i: United European Gastroenterology Journal. - : Wiley. - 2050-6406 .- 2050-6414. ; 7:7, s. 965-973
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Tidskriftsartikel (refereegranskat)abstract
- Background: Gastrointestinal symptoms can be triggered by food intake and psychological distress, but individual-level research on food-symptom and stress-symptom associations is scarce. Objective: We aimed to identify associations between food intake, psychological distress and gastrointestinal symptoms, and their implications for personalised clinical management. Methods: Through the mobile phone application mySymptoms, 163 users kept, for a median of five weeks, a diary of food intake, psychological distress and gastrointestinal symptoms. We quantified associations between these on the individual level. The presence of individual-level associations was compared over latent classes of daily symptom patterns. Results: Various gastrointestinal symptoms had demonstrable food-symptom associations (heartburn: 73%, discomfort: 67%, diarrhoea: 57%, bloating: 53%, and gas: 48%). Food-symptom associations for pain in the abdomen (33%) were concentrated in the latent class of individuals with pain in the morning (68%), rather than those with pain in the evening and night (27% and 10%, respectively, p < 0.001). Stress-symptom relations were also found, although only 18% of individuals reported psychological distress. Conclusion: Personal food-symptom and stress-symptom relations can be detected, and may translate into specific daily symptom patterns. A next step will be to let personal food-symptom and stress-symptom relations serve as the basis for personalised clinical management.
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| 19. |
- Desprez-Loustau, Marie-Laure, et al.
(författare)
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From leaf to continent : The multi-scale distribution of an invasive cryptic pathogen complex on oak
- 2018
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Ingår i: Fungal ecology. - : Elsevier BV. - 1754-5048 .- 1878-0083. ; 36, s. 39-50
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Tidskriftsartikel (refereegranskat)abstract
- The spatial distribution and niche differentiation of three closely related species (Erysiphe alphitoides, Erysiphe quercicola and Erysiphe hypophylla) causing oak powdery mildew was studied at scales ranging from the European continent, where they are invasive, to a single leaf. While E. alphitoides was dominant at all scales, E. quercicola and E. hypophylla had restricted geographic, stand and leaf distributions. The large-scale distributions were likely explained by climatic factors and species environmental tolerances, with E. quercicola being more frequent in warmer climates and E. hypophylla in colder climates. The extensive sampling and molecular analyses revealed the cryptic invasion of E. quercicola in nine countries from which it had not previously been recorded. The presence of the three species was also strongly affected by host factors, such as oak species and developmental stage. Segregation patterns between Erysiphe species were observed at the leaf scale, between and within leaf surfaces, suggesting competitive effects.
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| 20. |
- Drossman, D. A., et al.
(författare)
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Neuromodulators for Functional Gastrointestinal Disorders (Disorders of Gut−Brain Interaction): A Rome Foundation Working Team Report
- 2018
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Ingår i: Gastroenterology. - : Elsevier BV. - 0016-5085 .- 1528-0012. ; 154:4
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Tidskriftsartikel (refereegranskat)abstract
- Background & Aims: Central neuromodulators (antidepressants, antipsychotics, and other central nervous system−targeted medications) are increasingly used for treatment of functional gastrointestinal disorders (FGIDs), now recognized as disorders of gut−brain interaction. However, the available evidence and guidance for the use of central neuromodulators in these conditions is scanty and incomplete. In this Rome Foundation Working Team report, a multidisciplinary team summarized available research evidence and clinical experience to provide guidance and treatment recommendations. Methods: The working team summarized the literature on the pharmacology of central neuromodulators and their effects on gastrointestinal sensorimotor function and conducted an evidence-based review on their use for treating FGID syndromes. Because of the paucity of data for FGIDs, we included data for non-gastrointestinal painful disorders and specific symptoms of pain, nausea, and vomiting. This information was combined into a final document comprising a synthesis of available evidence and recommendations for clinical use guided by the research and clinical experience of the experts on the committee. Results: The evidence-based review on neuromodulators in FGID, restricted by the limited available controlled trials, was integrated with open-label studies and case series, along with the experience of experts to create recommendations using a consensus (Delphi) approach. Due to the diversity of conditions and complexity of treatment options, specific recommendations were generated for different FGIDs. However, some general recommendations include: (1) low to modest dosages of tricyclic antidepressants provide the most convincing evidence of benefit for treating chronic gastrointestinal pain and painful FGIDs and serotonin noradrenergic reuptake inhibitors can also be recommended, though further studies are needed; (2) augmentation, that is, adding a second treatment (adding quetiapine, aripiprazole, buspirone α2δ ligand agents) is recommended when a single medication is unsuccessful or produces side effects at higher dosages; (3) treatment should be continued for 6−12 months to potentially prevent relapse; and (4) implementation of successful treatment requires effective communication skills to improve patient acceptance and adherence, and to optimize the patient−provider relationship. Conclusions: Based on systematic and selectively focused review and the consensus of a multidisciplinary panel, we have provided summary information and guidelines for the use of central neuromodulators in the treatment of chronic gastrointestinal symptoms and FGIDs. Further studies are needed to confirm and refine these recommendations.
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| 21. |
- Ekholm, Adam, et al.
(författare)
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Dispersal, host genotype and environment shape the spatial dynamics of a parasite in the wild
- 2017
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Ingår i: Ecology. - : Wiley. - 0012-9658 .- 1939-9170. ; 98:10, s. 2574-2584
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Tidskriftsartikel (refereegranskat)abstract
- Dispersal, environment and genetic variation may all play a role in shaping host-parasite dynamics. Yet, in natural systems, their relative importance remains unresolved. Here, we do so for the epidemiology of a specialist parasite (Erysiphe alphitoides) on the pedunculate oak (Quercus robur). For this purpose, we combine evidence from a multi-year field survey and two dispersal experiments, all conducted at the landscape scale. Patterns detected in the field survey suggest that the parasite is structured as a metapopulation, with trees in denser oak stands characterized by higher parasite occupancy, higher colonization rates and lower extinction rates. The dispersal experiments revealed a major impact of the environment and of host genotype on the presence and abundance of the parasite, with a weaker but detectable imprint of dispersal limitation. Overall, our findings emphasize that dispersal, host genotype and the environment jointly shape the spatial dynamics of a parasite in the wild.
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| 22. |
- Ekholm, Adam, et al.
(författare)
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The forgotten season : the impact of autumn phenology on a specialist insect herbivore community on oak
- 2019
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Ingår i: Ecological Entomology. - : Wiley. - 0307-6946 .- 1365-2311. ; 44:3, s. 425-435
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Tidskriftsartikel (refereegranskat)abstract
- 1. Variation in spring phenology - like tree budburst - affects the structure of insect communities, but impacts of autumn phenology have been neglected. Many plant species have recently delayed their autumn phenology, and the timing of leaf senescence may be important for herbivorous insects.2. This study explored how an insect herbivore community associated with Quercus robur is influenced by variation in autumn phenology. For this, schools were asked to record, across the range of oak in Sweden, the autumn phenology of oaks and to conduct a survey of the insect community.3. To tease apart the relative impacts of climate from that of tree phenology, regional tree phenology was first modelled as a function of regional climate, and the tree-specific deviation from this relationship was then used as the metric of relative tree-specific phenology.4. At the regional scale, a warmer climate postponed oak leaf senescence. This was also reflected in the insect herbivore community: six out of 15 taxa occurred at a higher incidence and five out of 18 taxa were more abundant, in locations with a warmerclimate. Similarly, taxonomic richness and herbivory were higher in warmer locations.5. Trees with a relatively late autumn phenology had higher abundances of leaf miners (Phyllonorycter spp.). This caused lower community diversity and evenness on trees with later autumn phenology.6. The findings of the present study illustrate that both regional climate-driven patterns and local variation in oak autumn phenology contribute to shaping the insect herbivore community. Community patterns may thus shift with a changing climate.
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| 23. |
- Fernandez-Conradi, Pilar, et al.
(författare)
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Fungi reduce preference and performance of insect herbivores on challenged plants
- 2018
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Ingår i: Ecology. - : Wiley. - 0012-9658 .- 1939-9170. ; 99:2, s. 300-311
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Tidskriftsartikel (refereegranskat)abstract
- Although insect herbivores and fungal pathogens frequently share the same individual host plant, we lack general insights in how fungal infection affects insect preference and performance. We addressed this question in a meta-analysis of 1,113 case studies gathered from 101 primary papers that compared preference or performance of insect herbivores on control vs. fungus challenged plants. Generally, insects preferred, and performed better on, not challenged plants, regardless of experimental conditions. Insect response to fungus infection significantly differed according to fungus lifestyle, insect feeding guild, and the spatial scale of the interaction (local/distant). Insect performance was reduced on plants challenged by biotrophic pathogens or endophytes but not by necrotrophic pathogens. For both chewing and piercing-sucking insects, performance was reduced on challenged plants when interactions occurred locally but not distantly. In plants challenged by biotrophic pathogens, both preference and performance of herbivores were negatively impacted, whereas infection by necrotrophic pathogens reduced herbivore preference more than performance and endophyte infection reduced only herbivore performance. Our study demonstrates that fungi could be important but hitherto overlooked drivers of plant-herbivore interactions, suggesting both direct and plant-mediated effects of fungi on insect's behavior and development.
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| 24. |
- Grinsvall, Cecilia, et al.
(författare)
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Psychological factors selectively upregulate rectal pain perception in hypersensitive patients with irritable bowel syndrome.
- 2015
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Ingår i: Neurogastroenterology and motility : the official journal of the European Gastrointestinal Motility Society. - : Wiley. - 1365-2982. ; 27:12, s. 1772-82
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Tidskriftsartikel (refereegranskat)abstract
- Visceral hypersensitivity and psychological symptoms are frequent features in irritable bowel syndrome (IBS). Exploring mechanistic pathways leading to visceral hypersensitivity is of importance to direct future studies and treatment options. In this study, we evaluated the contribution of psychological factors to the perception of painful and non-painful rectal sensations in hyper- vs normosensitive IBS patients.
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| 25. |
- Grinsvall, Cecilia, et al.
(författare)
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Relationships between psychological state, abuse, somatization and visceral pain sensitivity in irritable bowel syndrome
- 2018
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Ingår i: United European Gastroenterology Journal. - : Wiley. - 2050-6406 .- 2050-6414. ; 6:2, s. 300-309
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Tidskriftsartikel (refereegranskat)abstract
- Background and objective: Psychological states may interfere with visceral sensitivity. Here we investigate associations between psychosocial factors and visceral sensitivity in irritable bowel syndrome (IBS). Methods: Two IBS patient cohorts (Cohort 1: n = 231, Rome II; Cohort 2: n = 141, Rome III) underwent rectal barostat testing, and completed questionnaires for anxiety, depression, somatization, and abuse. The associations between questionnaire measures and visceral sensitivity parameters were analyzed in three-step general linear models (step1: demographic and abuse variables; step 2: anxiety and depression; step 3: somatization). Results: Cohort 1. Pain threshold was positively associated with age and female gender, and negatively with adult sexual abuse and somatization. Pain referral area was negatively associated with age and positively with somatization and GI-specific anxiety, the latter effect mediated by somatization. Cohort 2. Pain threshold was positively associated with age and male gender, and negatively with adult sexual abuse. Pain intensity ratings were positively associated with somatization, female gender and depression, the latter effect mediated by somatization. Conclusion: Somatization is associated with most visceral sensitivity parameters, and mediates the effect of some psychological factors on visceral sensitivity. It may reflect a psychobiological sensitization process driving symptom generation in IBS. In addition, abuse history was found to independently affect some visceral sensitivity parameters.
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| 26. |
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| 27. |
- Hellström, Per M., et al.
(författare)
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The pharmacodynamics, safety and pharmacokinetics of single doses of the motilin agonist, camicinal, in type 1 diabetes mellitus with slow gastric emptying
- 2016
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Ingår i: British Journal of Pharmacology. - : Wiley. - 0007-1188 .- 1476-5381. ; 173:11, s. 1768-1777
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND PURPOSE Here we have investigated the pharmacokinetics, pharmacodynamics and safety of single doses of camicinal in type 1 diabetes mellitus (T1DM) patients with a history of slow gastric emptying with symptoms consistent with gastroparesis. EXPERIMENTAL APPROACH In a randomized, double-blind, placebo-controlled, incomplete block, three-period, two-centre crossover study, patients received oral administration of placebo and two of the three possible doses of camicinal (25, 50 or 125 mg). Gastric emptying (C-13-octanoic acid breath test), pharmacokinetics and safety were primary outcomes. KEY RESULTS Nine of the 10 patients enrolled completed the study. Gastric half-emptying time decreased by -95 min (95% CI: -156.8, -34.2) after a single dose of camicinal 125 mg compared with placebo (52 vs. 147 min, P < 0.05), representing a 65% improvement. A decrease of the gastric half-emptying time compared with placebo (approximately 39 min) was observed with camicinal 25 and 50 mg, representing a 27% reduction for both doses (not statistically significant). A positive exposure-response relationship was demonstrated across all doses. The effects of camicinal on gastric half-emptying time were not influenced by fasting glucose levels. Single doses up to 125 mg were well tolerated. Camicinal was well absorbed, exhibiting linear and approximately dose-proportional pharmacokinetic characteristics and a clear exposure-response relationship with gastric emptying. CONCLUSIONS AND IMPLICATIONS Camicinal significantly accelerated gastric emptying of solids in T1DM patients following administration of a single oral dose. Camicinal was well tolerated and exhibited similar pharmacokinetic characteristics in diabetic patients to those previously reported in healthy volunteers.
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| 28. |
- Moreira, Xoaquín, et al.
(författare)
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Latitudinal variation in plant chemical defences drives latitudinal patterns of leaf herbivory
- 2018
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Ingår i: Ecography. - : Wiley. - 0906-7590 .- 1600-0587. ; 41:7, s. 1124-1134
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Tidskriftsartikel (refereegranskat)abstract
- A long-standing paradigm in ecology holds that herbivore pressure and thus plant defences increase towards lower latitudes. However, recent work has challenged this prediction where studies have found no relationship or opposite trends where herbivory or plant defences increase at higher latitudes. Here we tested for latitudinal variation in herbivory, chemical defences (phenolic compounds), and nutritional traits (phosphorus and nitrogen) in leaves of a long-lived tree species, the English oak Quercus robur. We further investigated the underlying climatic and soil factors associated with such variation. Across 38 populations of Q. robur distributed along an 18 degrees latitudinal gradient, covering almost the entire latitudinal and climatic range of this species, we observed strong but divergent latitudinal gradients in leaf herbivory and leaf chemical defences and nutrients. As expected, there was a negative relationship between latitude and leaf herbivory where oak populations from lower latitudes exhibited higher levels of leaf herbivory. However, counter to predictions there was a positive relationship between leaf chemical defences and latitude where populations at higher latitudes were better defended. Similarly, leaf phosphorus and nitrogen increased with latitude. Path analysis indicated a significant (negative) effect of plant chemical defences (condensed tannins) on leaf herbivory, suggesting that the latitudinal gradient in leaf herbivory was driven by an inverse gradient in defensive investment. Leaf nutrients had no independent influence on herbivory. Further, we found significant indirect effects of precipitation and soil porosity on leaf herbivory, which were mediated by plant chemical defences. These findings suggest that abiotic factors shape latitudinal variation in plant defences and that these defences in turn underlie latitudinal variation in leaf herbivory. Overall, this study contributes to a better understanding of latitudinal variation in plant-herbivore interactions by determining the identity and modus operandi of abiotic factors concurrently shaping plant defences and herbivory.
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| 29. |
- Mursinoff, Sini, et al.
(författare)
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Spatial variation in soil biota mediates plant adaptation to a foliar pathogen
- 2017
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Ingår i: New Phytologist. - : Wiley. - 0028-646X .- 1469-8137. ; 214:2, s. 644-654
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Tidskriftsartikel (refereegranskat)abstract
- Theory suggests that below-ground spatial heterogeneity may mediate host-parasite evolutionary dynamics and patterns of local adaptation, but this has rarely been tested in natural systems. Here, we test experimentally for the impact of spatial variation in the abiotic and biotic soil environment on the evolutionary outcome of the interaction between the host plant Plantago lanceolata and its specialist foliar pathogen Podosphaera plantaginis. Plants showed no adaptation to the local soil environment in the absence of natural enemies. However, quantitative, but not qualitative, plant resistance against local pathogens was higher when plants were grown in their local field soil than when they were grown in nonlocal field soil. This pattern was robust when extending the spatial scale beyond a single region, but disappeared with soil sterilization, indicating that soil biota mediated plant adaptation. We conclude that below-ground biotic heterogeneity mediates above-ground patterns of plant adaptation, resulting in increased plant resistance when plants are grown in their local soil environment. From an applied perspective, our findings emphasize the importance of using locally selected seeds in restoration ecology and low-input agriculture.
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| 30. |
- Pohjanmies, Tahti, et al.
(författare)
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Genetic diversity and connectivity shape herbivore load within an oak population at its range limit
- 2015
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Ingår i: Ecosphere. - 2150-8925 .- 2150-8925. ; 6:6
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Tidskriftsartikel (refereegranskat)abstract
- Host genetic diversity and genotypic identity have been reported to affect the abundance, species richness and species diversity of associated herbivore communities. Recent work, however, suggests that these effects are highly context-dependent and that the magnitude and direction of the effects may vary with e.g., spatial factors and the amount of genetic variation present in the host population. Here, we use observational data on a Finnish oak (Quercus robur) population to examine whether low genetic diversity within peripheral populations reduces the impact of host genotype on associated herbivore communities. We first compared measures of genetic variation within Finnish oak populations with those recorded in more central parts of the species' range, confirming that genetic variation within the Finnish populations is comparatively low. Despite this result, we found consistent imprints of host genetic diversity on herbivore communities: herbivore load, but not the species richness, increased with host genetic diversity in both years and both spatial scales examined. Spatial connectivity of hosts increased herbivore diversity as well as abundance. While the similarity of herbivore communities increased with the genetic similarity among hosts, the effect of geographic distance was stronger. Overall, our findings identify a major role for spatial context in structuring oak-associated herbivore communities-but we still trace detectable imprints of host genotype at multiple spatial scales even in this peripheral, genetically impoverished oak population.
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| 31. |
- Pohl, D., et al.
(författare)
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Functional Dyspepsia and Severity of Psychologic Symptoms Associate With Postprandial Symptoms in Patients With Irritable Bowel Syndrome
- 2018
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Ingår i: Clinical Gastroenterology and Hepatology. - : Elsevier BV. - 1542-3565. ; 16:11, s. 1745-1753
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND & AIMS: Patients with irritable bowel syndrome (IBS) have an increased response of postprandial symptoms to a combined lactulose nutrient challenge test, compared with healthy volunteers. We investigated the associations among comorbid functional dyspepsia (FD), severity of psychologic symptoms, and breath test results in response to this test. METHODS: We performed a prospective study of 205 patients with IBS (Rome III criteria), 94 of whom also had FD (IBS-FD), and 83 healthy volunteers in Sweden from 2008 through 2015. All participants completed a breath hydrogen test after a 400-mL liquid meal with 25 g lactulose. Gastrointestinal (GI) symptom severity was assessed using a graded scale and digestive comfort was recorded before the meal and every 15 minutes until 240 minutes after the meal. GI symptom scores over time were compared between groups using linear mixed models with anxiety, depression, and somatization as covariates. RESULTS: Average levels of all GI symptoms varied over time among all groups (P < .0001). Patients with IBS-FD had higher levels of bloating (P = .004), abdominal pain (P = .005), and lower levels of digestive comfort (P < .01) than patients with only IBS. We observed a difference in increase in abdominal pain from baseline between IBS-FD and IBS groups (P = .013). Anxiety levels were associated with levels of all symptoms (all P < .025) except abdominal pain, which was associated with somatization severity (P < .0001). Furthermore, anxiety levels associated with level of exhaled hydrogen (P = .0042). CONCLUSIONS: In a prospective study of patients with IBS, we found those with FD to have increased GI symptoms before and after a liquidmeal with lactulose. Anxiety and somatization have an independent additional effect. The presence of comorbid FD and levels of psychologic symptoms affect reports of food-related symptoms in patients with IBS.
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| 32. |
- Rasmussen, Pil U., et al.
(författare)
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Multiscale patterns and drivers of arbuscular mycorrhizal fungal communities in the roots and root-associated soil of a wild perennial herb
- 2018
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Ingår i: New Phytologist. - : WILEY. - 0028-646X .- 1469-8137. ; 220:4, s. 1248-1261
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Tidskriftsartikel (refereegranskat)abstract
- Arbuscular mycorrhizal (AM) fungi form diverse communities and are known to influence above-ground community dynamics and biodiversity. However, the multiscale patterns and drivers of AM fungal composition and diversity are still poorly understood. We sequenced DNA markers from roots and root-associated soil from Plantago lanceolata plants collected across multiple spatial scales to allow comparison of AM fungal communities among neighbouring plants, plant subpopulations, nearby plant populations, and regions. We also measured soil nutrients, temperature, humidity, and community composition of neighbouring plants and nonAM root-associated fungi. AM fungal communities were already highly dissimilar among neighbouring plants (c. 30 cm apart), albeit with a high variation in the degree of similarity at this small spatial scale. AM fungal communities were increasingly, and more consistently, dissimilar at larger spatial scales. Spatial structure and environmental drivers explained a similar percentage of the variation, from 7% to 25%. A large fraction of the variation remained unexplained, which may be a result of unmeasured environmental variables, species interactions and stochastic processes. We conclude that AM fungal communities are highly variable among nearby plants. AM fungi may therefore play a major role in maintaining small-scale variation in community dynamics and biodiversity.
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| 33. |
- Rasmussen, Pil U., et al.
(författare)
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Plant and insect genetic variation mediate the impact of arbuscular mycorrhizal fungi on a natural plant-herbivore interaction
- 2017
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Ingår i: Ecological Entomology. - : Wiley. - 0307-6946 .- 1365-2311. ; 42:6, s. 793-802
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Tidskriftsartikel (refereegranskat)abstract
- 1. While both arbuscular mycorrhizal (AM) fungi and plant and insect genotype are well known to influence plant and herbivore growth and performance, information is lacking on how these factors jointly influence the relationship between plants and their natural herbivores. 2. The aim of the present study was to investigate how a natural community of arbuscular mycorrhizal fungi affects the growth of the perennial herb Plantago lanceolata L. (Plantaginaceae), as well as its interaction with the Glanville fritillary butterfly [Melitaea cinxia L. (Nymphalidae)]. For this, a multifactorial experiment was conducted using plant lines originating from multiple plant populations in the angstrom land Islands, Finland, grown either with or without mycorrhizal fungi. For a subset of plant lines, the impact of mycorrhizal inoculation, plant line, and larval family on the performance of M. cinxia larvae were tested. 3. Arbuscular mycorrhizal inoculation did not have a consistently positive or negative impact on plant growth or herbivore performance. Instead, plant genetic variation mediated the impact of arbuscular mycorrhizal fungi on plant growth, and both plant genetic variation and herbivore genetic variation mediated the response of the herbivore. For both the plant and insect, the impact of the arbuscular mycorrhizal community ranged from mutualistic to antagonistic. Overall, the present findings illustrate that genetic variation in response to mycorrhizal fungi may play a key role in the ecology and evolution of plant-insect interactions.
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| 34. |
- Rasmussen, Pil Uthaug, 1987-
(författare)
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Plant-associated soil communities : Patterns, drivers and aboveground consequences
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Soil contains a wealth of diversity – bacteria, fungi, nematodes, arthropods and earthworms are just some of the many organisms found belowground. These organisms play an important role in shaping the soil environment and they strongly influence plant fitness, diversity and community composition. Their impact even cascades up to affect aboveground species interactions. Ultimately, belowground organisms are a vital part of ecosystem functioning. Nevertheless, most of the diversity and ecology of belowground organisms are to this day unknown, and increasing our insights into the role and ecology of soil organisms is of importance for natural and agricultural systems.The main goal of this thesis was to investigate spatial patterns of plant-associated soil communities (I, II), to identify the drivers of such spatial patterns (I, II, III), and to study some of the consequences of belowground spatial patterns for aboveground species interactions (IV). To answer these questions, I used both observational studies and multifactorial experiments in combination with microscopy and metabarcoding. I focused on the plant Plantago lanceolata (ribwort plantain) and its root-associated soil microbes, with a strong emphasis on arbuscular mycorrhizal fungi, an important group of root symbionts.I found that in natural environments arbuscular mycorrhizal fungal communities frequently show high small-scale variation (I). In the following work I showed that the pattern of high small-scale heterogeneity may be due to dispersal limitation (II), abiotic conditions such as pH, soil nutrients and climate (I, III), and biotic conditions, such as interspecific community composition and genetic variation (I, II). The high variation at small spatial scales (I) in combination with genetic variation of plants and insects (IV) may help maintain high local heterogeneity in aboveground plant-associated communities, thereby influencing aboveground diversity and dynamics.The insight gained here has increased our general knowledge on the distribution of soil microbes and the interactions taking place above and belowground. It has furthermore laid a foundation for future work on the world of soil microbes and their implications aboveground.
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| 35. |
- Rasmussen, Pil U., et al.
(författare)
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The impact of dispersal, plant genotype and nematodes on arbuscular mycorrhizal fungal colonization
- 2019
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Ingår i: Soil Biology and Biochemistry. - : Elsevier BV. - 0038-0717 .- 1879-3428. ; 132, s. 28-35
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Tidskriftsartikel (refereegranskat)abstract
- While the majority of parasitic and mutualistic microbes have the potential for long-range dispersal, the high turnover in community composition among nearby hosts has often been interpreted to reflect dispersal constraints. To resolve this apparent contradiction, we need further insights into the relative importance of dispersal limitation, host genotype and the biotic environment on the colonization process. We focused on the important root symbionts, the arbuscular mycorrhizal (AM) fungi. We studied AM fungal colonization ability in a controlled mesocosm setting, where we placed Plantago lanceolata plants belonging to four different genotypes in sterile soil at 10, 30 and 70 cm from a central AM fungal inoculated P. lanceolata plant. In part of the mesocosms, we also inoculated the source plants with nematodes. AM fungi colonized receiver plants <1 m away over the course of ten weeks, with a strong effect of distance from source plant on AM fungal colonization. Plant genotype influenced AM fungal colonization during the early stages of colonization, while nematode inoculation had no effect on AM fungal colonization. Overall, the effect of both dispersal limitation and plant genetic variation may underlie the small-scale heterogeneity found in natural AM fungal communities.
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| 36. |
- Shaheen, S. M., et al.
(författare)
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Redox chemistry of vanadium in soils and sediments : Interactions with colloidal materials, mobilization, speciation, and relevant environmental implications - A review
- 2019
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Ingår i: Advances in Colloid and Interface Science. - : Elsevier. - 0001-8686 .- 1873-3727. ; 265, s. 1-13
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Tidskriftsartikel (refereegranskat)abstract
- Vanadium (V), although serving as an important component of industrial activities, has bioinorganic implications to pose highly toxic hazards to humans and animals. Soils and sediments throughout the world exhibit wide ranges of vanadium concentrations. Although vanadium toxicity varies between different species, it is mainly controlled by soil redox potential (E H ). Nonetheless, knowledge of the redox geochemistry of vanadium lags in comparison to what is known about other potentially toxic elements (PTEs). In particular, the redox-induced speciation and mobilization of vanadium in soils and sediments and the associated risks to the environment have not been reviewed to date. Therefore, this review aims to address 1) the content and geochemical fate of vanadium in soils and sediments, 2) its redox-induced release dynamics, 3) redox-mediated chemical reactions between vanadium and soil organic and inorganic colloidal materials in soil solution, 4) its speciation in soil solution and soil-sediments, and 5) the use of advanced geochemical and spectroscopic techniques to investigate these complex systems. Vanadium (+5) is the most mobile and toxic form of its species while being the thermodynamically stable valence state in oxic environments, while vanadium (+3) might be expected to be predominant under euxinic (anoxic and sulfidic) conditions. Vanadium can react variably in response to changing soil E H : under anoxic conditions, the mobilization of vanadium can decrease because vanadium (+5) can be reduced to relatively less soluble vanadium (+4) via inorganic reactions such as with H 2 S and organic matter and by metal-reducing microorganisms. On the other hand, dissolved concentrations of vanadium can increase at low E H in many soils to reveal a similar pattern to that of Fe, which may be due to the reductive dissolution of Fe(hydr)oxides and the release of the associated vanadium. Those differences in vanadium release dynamics might occur as a result of the direct impact of E H on vanadium speciation in soil solution and soil sediments, and/or because of the E H -dependent changes in soil pH, chemistry of (Fe)(hydr)oxides, and complexation with soil organic carbon. Release dynamics of vanadium in soils may also be affected positively by soil pH and the release of aromatic organic compounds. X-ray absorption spectroscopy (XAS) is a powerful tool to investigate the speciation of vanadium present in soil. X-ray absorption near edge structure (XANES) is often used to constrain the average valence state of vanadium in soils and sediments, and in limited cases extended X-ray absorption fine structure (EXAFS) analysis has been used to determine the average molecular coordination environment of vanadium in soil components. In conclusion, this review presents the state of the art about the redox geochemistry of vanadium and thus contributes to a better understanding of the speciation, potential mobilization, and environmental hazards of vanadium in the near-surface environment of uplands, wetlands, and agricultural ecosystems as affected by various colloidal particles. Further research is needed to elucidate the geochemistry and speciation of vanadium in the dissolved, colloidal, and soil sediments phases, including the determination of factors that control the redox geochemistry of vanadium.
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| 37. |
- Simrén, Magnus, 1966, et al.
(författare)
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Cumulative Effects of Psychologic Distress, Visceral Hypersensitivity, and Abnormal Transit on Patient-reported Outcomes in Irritable Bowel Syndrome
- 2019
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Ingår i: Gastroenterology. - : Elsevier BV. - 0016-5085. ; 157:2, s. 391-402
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND & AIMS: Little is known about the link between pathophysiologic factors and symptoms of irritable bowel syndrome (IBS), or whether these factors have cumulative effects on patient-reported outcomes (PROs). We investigated whether pathophysiologic alterations associated with IBS have cumulative or independent effects on PROs. METHODS: We performed a retrospective analysis of data from 3 cohorts of patients with IBS (n = 407; 74% female; mean age, 36 +/- 12 years), based on Rome II or Rome III criteria, seen at a specialized unit for functional gastrointestinal disorders in Sweden from 2002 through 2014. All patients underwent assessments of colonic transit time (radiopaque markers); compliance, allodynia, and hyperalgesia (rectal barostat); anxiety and depression (Hospital Anxiety and Depression scale), as pathophysiologic factors. Dysfunction was defined by available normal values. PROs included IBS symptom severity, somatic symptom severity, and disease-specific quality of life. RESULTS: Allodynia was observed in 36% of patients, hyperalgesia in 22%, accelerated colonic transit in 18%, delayed transit in 7%, anxiety in 52%, and depression in 24%: each of these factors was associated with severity of at least 1 symptom of IBS. Rectal compliance was not associated with more severe symptoms of IBS. At least 3 pathophysiologic factors were present in 20% of patients, 2 in 30%, 1 in 31%, and none in 18%. With increasing number of pathophysiologic abnormalities, there was a gradual increase in IBS symptom severity (P < .0001) and somatic symptom severity (P < .0001), and a gradual reduction in quality of life (P < .0001). CONCLUSION: Visceral hypersensitivity, including allodynia and hyperalgesia, abnormal colonic transit, and psychologic factors are all associated with IBS symptoms. These factors have a cumulative effect on gastrointestinal and non-gastrointestinal symptoms, as well as on quality of life, in patients with IBS and are therefore relevant treatment targets.
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| 38. |
- Simrén, Magnus, 1966, et al.
(författare)
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New treatments and therapeutic targets for IBS and other functional bowel disorders
- 2018
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Ingår i: Nature Reviews Gastroenterology & Hepatology. - : Springer Science and Business Media LLC. - 1759-5045 .- 1759-5053. ; 15:10, s. 589-605
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Tidskriftsartikel (refereegranskat)abstract
- Functional bowel disorders (FBDs) are a spectrum of disorders characterized by combinations of symptoms attributable to the lower gastrointestinal tract. Most current first-line therapies for IBS and other FBDs target the predominant symptom and mainly affect one symptom in the symptom complex. Additional broadly effective treatment alternatives targeting the entire symptom complex are needed. New drugs for FBDs (such as lubiprostone, linaclotide, plecanatide, prucalopride, eluxadoline and rifaximin) target key mechanisms in the pathophysiology of these disorders and improve both the abnormal bowel habit and other key symptoms, such as abdominal pain and bloating. The current development of new treatment alternatives is focusing on different aspects of the complex pathophysiology of IBS and other FBDs: gut microenvironment (via diet and modulation of gut microbiota), enterohepatic circulation of bile acids, gastrointestinal secretion, motility and sensation, gut-brain interactions, gut barrier function and the immune system within the gastrointestinal tract. Studies also suggest that personalized treatment of IBS and other FBDs is possible using various diagnostic markers.
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| 39. |
- Simrén, Magnus, 1966, et al.
(författare)
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Visceral hypersensitivity is associated with GI symptom severity in functional GI disorders: consistent findings from five different patient cohorts
- 2018
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Ingår i: Gut. - : BMJ. - 0017-5749 .- 1468-3288. ; 67:2, s. 255-262
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Tidskriftsartikel (refereegranskat)abstract
- Objective Our aim was to evaluate the association between visceral hypersensitivity and GI symptom severity in large cohorts of patients with functional GI disorder (FGID) and to adjust for psychological factors and general tendency to report symptoms. Design We included five cohorts of patients with FGIDs (IBS or functional dyspepsia; n=1144), who had undergone visceral sensitivity testing using balloon distensions (gastric fundus, descending colon or rectum) and completed questionnaires to assess GI symptom severity, non-GI somatic symptoms, anxiety and depression. Subjects were divided into sensitivity tertiles based on pain/discomfort thresholds. GI symptom severity was compared between sensitivity tertiles in each cohort and corrected for somatisation, and anxiety and depression. Results In all five cohorts, GI symptom severity increased gradually with increasing visceral sensitivity, with significant differences in GI symptom severity between the sensitivity tertiles (p<0.0001), with small to medium effect sizes (partial eta(2): 0.047-0.11). The differences between sensitivity tertiles remained significant in all cohorts after correction for anxiety and depression, and also after correction for non-GI somatic symptom reporting in all of the cohorts (p<0.05). Conclusions A gradual increase in GI symptom severity with increasing GI sensitivity was demonstrated in IBS and functional dyspepsia, which was consistent across several large patient groups from different countries, different methods to assess sensitivity and assessments in different parts of the GI tract. This association was independent of tendency to report symptoms or anxiety/depression comorbidity. These findings confirm that visceral hypersensitivity is a contributor to GI symptom generation in FGIDs.
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| 40. |
- Tack, Ayco J. M., et al.
(författare)
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Increasing frequency of low summer precipitation synchronizes dynamics and compromises metapopulation stability in the Glanville fritillary butterfly
- 2015
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Ingår i: Proceedings of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 282:1806
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Tidskriftsartikel (refereegranskat)abstract
- Climate change is known to shift species' geographical ranges, phenologies and abundances, but less is known about other population dynamic consequences. Here, we analyse spatio-temporal dynamics of the Glanville fritillary butterfly (Melitaea cinxia) in a network of 4000 dry meadows during 21 years. The results demonstrate two strong, related patterns: the amplitude of year-to-year fluctuations in the size of the metapopulation as a whole has increased, though there is no long-term trend in average abundance; and there is a highly significant increase in the level of spatial synchrony in population dynamics. The increased synchrony cannot be explained by increasing within-year spatial correlation in precipitation, the key environmental driver of population change, or in per capita growth rate. On the other hand, the frequency of drought during a critical life-history stage (early larval instars) has increased over the years, which is sufficient to explain the increasing amplitude and the expanding spatial synchrony in metapopulation dynamics. Increased spatial synchrony has the general effect of reducing long-term metapopulation viability even if there is no change in average metapopulation size. This study demonstrates how temporal changes in weather conditions can lead to striking changes in spatio-temporal population dynamics.
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| 41. |
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| 42. |
- Wilpart, Katarina, et al.
(författare)
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Coping Skills Are Associated With Gastrointestinal Symptom Severity and Somatization in Patients With Irritable Bowel Syndrome
- 2017
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Ingår i: Clinical Gastroenterology and Hepatology. - : Elsevier BV. - 1542-3565. ; 15:10
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND & AIMS: Coping resources and processes are altered in patients with irritable bowel syndrome (IBS). We investigated the relationship between coping resources and gastrointestinal (GI) and extra-intestinal symptom severity in patients with IBS and potential mediators of this relationship. METHODS: We performed a cross-sectional study of 216 patients with IBS attending a secondary/tertiary care specialized outpatient center in Sweden from 2003 through 2007. We collected data on coping resources, levels of anxiety (general and GI specific), depressive symptoms, levels of GI symptoms, and extraintestinal somatic symptoms (somatization) by administering validated selfreport questionnaires. General Linear Models were used to assess associations and mediation. RESULTS: GI symptoms: low levels of physical coping resources (practice of activities that are beneficial for health; P=.0016), high levels of general anxiety symptoms (P=.033), and GI-specific anxiety symptoms (P <.0001), but not depressive symptoms (P=.89), were independently associated with GI symptom levels (R-2=0.31). Anxiety and GI-specific anxiety partially mediated the effect of physical coping. Somatization: low levels of physical coping resources (P=.003), high levels of anxiety (P=.0147), depressive (P=.0005), and GI-specific anxiety symptoms (P=.06) were associated with somatization levels (R-2=0.35). Levels of general and GI-specific anxiety and depressive symptoms partially mediated this physical coping effect. The effect of psychological coping resources (including optimism, social support, and accepting/expressing emotions) on somatization levels was not significant (P=.98), but was fully mediated by levels of anxiety and depressive symptoms, and partially by levels of GI-specific anxiety symptoms. CONCLUSIONS: In a cross-sectional study of patients with IBS in Sweden, we found associations of levels of coping resources with GI and extraintestinal symptom severity; these associations were mediated by levels of anxiety and depressive symptoms. Although confirmation in longitudinal studies is needed, this identifies coping as a potential psychological treatment target in IBS.
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| 43. |
- Zheng, Chaozhi, et al.
(författare)
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Beyond metacommunity paradigms : habitat configuration, life history, and movement shape an herbivore community on oak
- 2015
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Ingår i: Ecology. - : Wiley. - 0012-9658 .- 1939-9170. ; 96:12, s. 3175-3185
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Tidskriftsartikel (refereegranskat)abstract
- Many empirical studies of metacommunities have focused on the classification of observational patterns into four contrasting paradigms characterized by different levels of movement and habitat heterogeneity. However, deeper insight into the underlying local and regional processes may be derived from a combination of long-term observational data and experimental studies. With the aim of exploring forces structuring the insect metacommunity on oak, we fit a hierarchical Bayesian state-space model to data from observations and experiments. The fitted model reveals large variation in species-specific dispersal abilities and basic reproduction numbers, R-0. The residuals from the model show only weak correlations among species, suggesting a lack of strong interspecific interactions. Simulations with model-derived parameter estimates indicate that habitat configuration and species attributes both contribute substantially to structuring insect communities. Overall, our findings demonstrate that community-level variation in movement and life history are key drivers of metacommunity dynamics.
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