| 1. |
- Callaghan, Terry, et al.
(författare)
-
Multi-Decadal Changes in Tundra Environments and Ecosystems : Synthesis of the International Polar Year-Back to the Future Project (IPY-BTF)
- 2011
-
Ingår i: Ambio. - : Springer Science and Business Media LLC. - 0044-7447 .- 1654-7209. ; 40:6, s. 705-716
-
Tidskriftsartikel (refereegranskat)abstract
- Understanding the responses of tundra systemsto global change has global implications. Most tundraregions lack sustained environmental monitoring and oneof the only ways to document multi-decadal change is toresample historic research sites. The International PolarYear (IPY) provided a unique opportunity for such researchthrough the Back to the Future (BTF) project (IPY project#512). This article synthesizes the results from 13 paperswithin this Ambio Special Issue. Abiotic changes includeglacial recession in the Altai Mountains, Russia; increasedsnow depth and hardness, permafrost warming, andincreased growing season length in sub-arctic Sweden;drying of ponds in Greenland; increased nutrient availabilityin Alaskan tundra ponds, and warming at mostlocations studied. Biotic changes ranged from relativelyminor plant community change at two sites in Greenland tomoderate change in the Yukon, and to dramatic increasesin shrub and tree density on Herschel Island, and in subarcticSweden. The population of geese tripled at one sitein northeast Greenland where biomass in non-grazed plotsdoubled. A model parameterized using results from a BTFstudy forecasts substantial declines in all snowbeds andincreases in shrub tundra on Niwot Ridge, Colorado overthe next century. In general, results support and provideimproved capacities for validating experimental manipulation,remote sensing, and modeling studies.
|
|
| 2. |
- Baldanzi, Gabriel, et al.
(författare)
-
Accelerometer-based physical activity is associated with the gut microbiota in 8416 individuals in SCAPIS.
- 2024
-
Ingår i: EBioMedicine. - : Elsevier. - 2352-3964. ; 100
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Previous population-based studies investigating the relationship between physical activity and the gut microbiota have relied on self-reported activity, prone to reporting bias. Here, we investigated the associations of accelerometer-based sedentary (SED), moderate-intensity (MPA), and vigorous-intensity (VPA) physical activity with the gut microbiota using cross-sectional data from the Swedish CArdioPulmonary bioImage Study.METHODS: In 8416 participants aged 50-65, time in SED, MPA, and VPA were estimated with hip-worn accelerometer. Gut microbiota was profiled using shotgun metagenomics of faecal samples. We applied multivariable regression models, adjusting for sociodemographic, lifestyle, and technical covariates, and accounted for multiple testing.FINDINGS: Overall, associations between time in SED and microbiota species abundance were in opposite direction to those for MPA or VPA. For example, MPA was associated with lower, while SED with higher abundance of Escherichia coli. MPA and VPA were associated with higher abundance of the butyrate-producers Faecalibacterium prausnitzii and Roseburia spp. We observed discrepancies between specific VPA and MPA associations, such as a positive association between MPA and Prevotella copri, while no association was detected for VPA. Additionally, SED, MPA and VPA were associated with the functional potential of the microbiome. For instance, MPA was associated with higher capacity for acetate synthesis and SED with lower carbohydrate degradation capacity.INTERPRETATION: Our findings suggest that sedentary and physical activity are associated with a similar set of gut microbiota species but in opposite directions. Furthermore, the intensity of physical activity may have specific effects on certain gut microbiota species.FUNDING: European Research Council, Swedish Heart-Lung Foundation, Swedish Research Council, Knut and Alice Wallenberg Foundation.
|
|
| 3. |
- Dekki Shalaly, Nancy, et al.
(författare)
-
Silk matrices promote formation of insulin-secreting islet-like clusters
- 2016
-
Ingår i: Biomaterials. - : Elsevier BV. - 0142-9612 .- 1878-5905. ; 90, s. 50-61
-
Tidskriftsartikel (refereegranskat)abstract
- Ex vivo expansion of endocrine cells constitutes an interesting alternative to be able to match the unmet need of transplantable pancreatic islets. However, endocrine cells become fragile once removed from their extracellular matrix (ECM) and typically become senescent and loose insulin expression during conventional 2D culture. Herein we develop a protocol where 3D silk matrices functionalized with ECM-derived motifs are used for generation of insulin-secreting islet-like clusters from mouse and human primary cells. The obtained clusters were shown to attain an islet-like spheroid shape and to maintain functional insulin release upon glucose stimulation in vitro. Furthermore, in vivo imaging of transplanted murine clusters showed engraftment with increasing vessel formation during time. There was no sign of cell death and the clusters maintained or increased in size throughout the period, thus suggesting a suitable cluster size for transplantation.
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
- Fromell, Karin, et al.
(författare)
-
The effect of airborne Palladium nanoparticles on human lung cells, endothelium and blood-A combinatory approach using three in vitro models
- 2023
-
Ingår i: Toxicology in Vitro. - : Elsevier. - 0887-2333 .- 1879-3177. ; 89
-
Tidskriftsartikel (refereegranskat)abstract
- A better understanding of the mechanisms behind adverse health effects caused by airborne fine particles and nanoparticles (NP) is essential to improve risk assessment and identification the most critical particle exposures. While the use of automobile catalytic converters is decreasing the exhausts of harmful gases, concentrations of fine airborne particles and nanoparticles (NPs) from catalytic metals such as Palladium (Pd) are reaching their upper safe level. Here we used a combinatory approach with three in vitro model systems to study the toxicity of Pd particles, to infer their potential effects on human health upon inhalation. The three model systems are 1) a lung system with human lung cells (ALI), 2) an endothelial cell system and 3) a human whole blood loop system. All three model systems were exposed to the exact same type of Pd NPs. The ALI lung cell exposure system showed a clear reduction in cell growth from 24 h onwards and the effect persisted over a longer period of time. In the endothelial cell model, Pd NPs induced apoptosis, but not to the same extent as the most aggressive types of NPs such as TiO2. Similarly, Pd triggered clear coagulation and contact system activation but not as forcefully as the highly thrombogenic TiO2 NPs. In summary, we show that our 3-step in vitro model of the human lung and surrounding vessels can be a useful tool for studying pathological events triggered by airborne fine particles and NPs.
|
|
| 7. |
|
|
| 8. |
- Göransson, Katarina, 1974-, et al.
(författare)
-
Measurement of peripheral venous catheter-related phlebitis : a cross-sectional study.
- 2017
-
Ingår i: The Lancet Haematology. - 2352-3026. ; 4:9, s. e424-e430
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Many instruments for measurement of peripheral venous catheter (PVC)-related phlebitis are available, but no consensus exists on their applicability in clinical practice. This absence of consensus affects the ability to identify and compare proportions of PVCs causing phlebitis within and across hospitals as the range varies between 2% and 62% in previous studies. We hypothesised that the instruments' ability to identify phlebitis varies. The aim of this study is to illustrate the complexity of application of phlebitis instruments to a clinical dataset.METHODS: In this cross-sectional study, we applied 17 instruments for phlebitis identification (divided into three groups [instruments using definitions, severity rating systems, and scoring systems]) to PVCs in adult patients admitted to 12 inpatient units at Karolinska University Hospital in Sweden. We calculated the proportion of PVCs causing phlebitis on the basis of each instrument's minimum criterion for phlebitis. We also analysed each instrument's face validity. We compared proportions using the Z test.FINDINGS: On the basis of data collected between Feb 2, 2009, and Feb 20, 2009, May 18, 2009, and June 5, 2009, and Feb 8, 2010, and Feb 26, 2010, we applied 17 instruments for phlebitis identification (eight instruments using definitions, seven severity rating systems, and two scoring systems) to 1175 observed PVCs in 1032 patients. The highest number of PVCs causing phlebitis generated by definitions was 137 (11·7%), by severity rating systems was 395 (33·6%), and by scoring systems was 363 (30·9%). The proportion generated by instruments using definitions was significantly different to that of both the severity rating (difference 21·9% [95% CI 18·6-25·2]; p<0·0001) and scoring (19·2% [12·0-26·4]; p<0·0001) systems. Proportions did not differ significantly between severity rating systems and scoring system (difference 2·7% [95% CI -1·1 to 6·6]; p=0·16). The proportion within instruments ranged from less than 1% to 28%. We identified face validity issues, such as use of indistinct or complex measurements and inconsistent measurements or definitions.INTERPRETATION: Our study highlights several concerns regarding instruments to measure phlebitis published in the scientific community. From a work environment and patient safety perspective, clinical staff engaged in PVC management should be aware of the absence of adequately validated instruments for phlebitis assessment. We suggest that researchers within the field of PVC come together in a joint research programme aiming to develop valid and reliable methods that accurately identify PVC-related adverse events that also includes decision support for clinical staff concerning clinical indications for PVC removal. Such actions could lead to a revised view on what is best practice for management of PVCs.FUNDING: None.
|
|
| 9. |
- Johansson, Maria E, 1977, et al.
(författare)
-
alpha 7 Nicotinic Acetylcholine Receptor Is Expressed in Human Atherosclerosis and Inhibits Disease in Mice-Brief Report
- 2014
-
Ingår i: Arteriosclerosis Thrombosis and Vascular Biology. - : Ovid Technologies (Wolters Kluwer Health). - 1079-5642 .- 1524-4636. ; 34:12, s. 2632-2636
-
Tidskriftsartikel (refereegranskat)abstract
- Objective-Cholinergic pathways of the autonomic nervous system are known to modulate inflammation. Because atherosclerosis is a chronic inflammatory condition, we tested whether cholinergic signaling operates in this disease. We have analyzed the expression of the alpha 7 nicotinic acetylcholine receptor (alpha 7nAChR) in human atherosclerotic plaques and studied its effects on the development of atherosclerosis in the hypercholesterolemic Ldlr(-/-) mouse model. Approach and Results-alpha 7nAChR protein was detected on T cells and macrophages in surgical specimens of human atherosclerotic plaques. To study the role of alpha 7nAChR signaling in atherosclerosis, male Ldlr(-/-) mice were lethally irradiated and reconstituted with bone marrow from wild-type or alpha 7nAChR-deficient animals. Ablation of hematopoietic cell alpha 7nAChR increased aortic atherosclerosis by 72%. This was accompanied by increased aortic interferon-gamma mRNA, implying increased Th1 activity in the absence of a7nAChR signaling. Conclusions-The present study shows that signaling through hematopoietic alpha 7nAChR inhibits atherosclerosis and suggests that it operates by modulating immune inflammation. Given the observation that alpha 7nAChR is expressed by T cells and macrophages in human plaques, our findings support the notion that cholinergic regulation may act to inhibit disease development also in man.
|
|
| 10. |
- Johansson, Ulrika, 1974-, et al.
(författare)
-
Assembly of functionalized silk together with cells to obtain proliferative 3D cultures integrated in a network of ECM-like microfibers
- 2019
-
Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 9, s. 1-13
-
Tidskriftsartikel (refereegranskat)abstract
- Tissues are built of cells integrated in an extracellular matrix (ECM) which provides a three-dimensional (3D) microfiber network with specific sites for cell anchorage. By genetic engineering, motifs from the ECM can be functionally fused to recombinant silk proteins. Such a silk protein, FN-silk, which harbours a motif from fibronectin, has the ability to self-assemble into networks of microfibers under physiological-like conditions. Herein we describe a method by which mammalian cells are added to the silk solution before assembly, and thereby get uniformly integrated between the formed microfibers. In the resulting 3D scaffold, the cells are highly proliferative and spread out more efficiently than when encapsulated in a hydrogel. Elongated cells containing filamentous actin and defined focal adhesion points confirm proper cell attachment to the FN-silk. The cells remain viable in culture for at least 90 days. The method is also scalable to macro-sized 3D cultures. Silk microfibers formed in a bundle with integrated cells are both strong and extendable, with mechanical properties similar to that of artery walls. The described method enables differentiation of stem cells in 3D as well as facile co-culture of several different cell types. We show that inclusion of endothelial cells leads to the formation of vessel-like structures throughout the tissue constructs. Hence, silk-assembly in presence of cells constitutes a viable option for 3D culture of cells integrated in a ECM-like network, with potential as base for engineering of functional tissue.
|
|
