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- Dekki Shalaly, Nancy, et al.
(författare)
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Silk matrices promote formation of insulin-secreting islet-like clusters
- 2016
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Ingår i: Biomaterials. - : Elsevier BV. - 0142-9612 .- 1878-5905. ; 90, s. 50-61
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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.
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| 5. |
- Göransson, Katarina, 1974-, et al.
(författare)
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Measurement of peripheral venous catheter-related phlebitis : a cross-sectional study.
- 2017
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Ingår i: The Lancet Haematology. - 2352-3026. ; 4:9, s. e424-e430
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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.
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- Johansson, Ulrika, 1974-, et al.
(författare)
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Assembly of functionalized silk together with cells to obtain proliferative 3D cultures integrated in a network of ECM-like microfibers
- 2019
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Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 9, s. 1-13
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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.
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| 7. |
- Johansson, Ulrika, 1974-, et al.
(författare)
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Pancreatic Islet Survival and Engraftment Is Promoted by Culture on Functionalized Spider Silk Matrices
- 2015
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 19:10, s. 1-21
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Tidskriftsartikel (refereegranskat)abstract
- Transplantation of pancreatic islets is one approach for treatment of diabetes, however, hampered by the low availability of viable islets. Islet isolation leads to disruption of the environment surrounding the endocrine cells, which contributes to eventual cell death. The reestablishment of this environment is vital, why we herein investigated the possibility of using recombinant spider silk to support islets in vitro after isolation. The spider silk protein 4RepCT was formulated into three different formats; 2D-film, fiber mesh and 3D-foam, in order to provide a matrix that can give the islets physical support in vitro. Moreover, cell-binding motifs from laminin were incorporated into the silk protein in order to create matrices that mimic the natural cell environment. Pancreatic mouse islets were thoroughly analyzed for adherence, necrosis and function after in vitro maintenance on the silk matrices. To investigate their suitability for transplantation, we utilized an eye model which allows in vivo imaging of engraftment. Interestingly, islets that had been maintained on silk foam during in vitro culture showed improved revascularization. This coincided with the observation of preserved islet architecture with endothelial cells present after in vitro culture on silk foam. Selected matrices were further evaluated for long-term preservation of human islets. Matrices with the cell-binding motif RGD improved human islet maintenance (from 36% to 79%) with preserved islets architecture and function for over 3 months in vitro. The islets established cell-matrix contacts and formed vessel-like structures along the silk. Moreover, RGD matrices promoted formation of new, insulin-positive islet-like clusters that were connected to the original islets via endothelial cells. On silk matrices with islets from younger donors (<35 year), the amount of newly formed islet-like clusters found after 1 month in culture were almost double compared to the initial number of islets added.
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| 8. |
- Key, Timothy J., et al.
(författare)
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Consumption of Meat, Fish, Dairy Products, Eggs and Risk of Ischemic Heart Disease : A Prospective Study of 7198 Incident Cases Among 409,885 Participants in the Pan-European EPIC Cohort
- 2019
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Ingår i: Circulation. - : Wolters Kluwer. - 0009-7322 .- 1524-4539. ; 139:25, s. 2835-2845
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: There is uncertainty about the relevance of animal foods to the etiology of ischemic heart disease (IHD). We examined meat, fish, dairy products and eggs and risk for IHD in the pan-European EPIC cohort.METHODS: A prospective study of 409,885 men and women in nine European countries. Diet was assessed using validated questionnaires, calibrated using 24-hour recalls. Lipids and blood pressure were measured in a subsample. During 12.6 years mean follow up, 7198 participants had a myocardial infarction or died from IHD. The relationships of animal foods with risk were examined using Cox regression with adjustment for other animal foods and relevant covariates.RESULTS: The hazard ratio (HR) for IHD was 1.19 (95% CI 1.06-1.33) for a 100 g/d increment in intake of red and processed meat, and this remained significant after excluding the first 4 years of follow-up (HR 1.25 [1.09-1.42]). Risk was inversely associated with intakes of yogurt (HR 0.93 [0.89-0.98] per 100 g/d increment), cheese (HR 0.92 [0.86-0.98] per 30 g/d increment) and eggs (HR 0.93 [0.88-0.99] per 20 g/d increment); the associations with yogurt and eggs were attenuated and non-significant after excluding the first 4 years of follow-up. Risk was not significantly associated with intakes of poultry, fish or milk. In analyses modelling dietary substitutions, replacement of 100 kcal/d from red and processed meat with 100 kcal/d from fatty fish, yogurt, cheese or eggs was associated with approximately 20% lower risk of IHD. Consumption of red and processed meat was positively associated with serum non-HDL cholesterol concentration and systolic blood pressure, and consumption of cheese was inversely associated with serum non-HDL cholesterol.CONCLUSIONS: Risk for IHD was positively associated with consumption of red and processed meat, and inversely associated with consumption of yogurt, cheese and eggs, although the associations with yogurt and eggs may be influenced by reverse causation bias. It is not clear whether the associations with red and processed meat and cheese reflect causality, but they were consistent with the associations of these foods with plasma non-HDL cholesterol, and for red and processed meat with systolic blood pressure, which could mediate such effects.
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| 9. |
- Wester Oxelgren, Ulrika, 1960-, et al.
(författare)
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An intervention targeting social, communication and daily activity skills in children and adolescents with Down syndrome and autism : a pilot study
- 2019
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Ingår i: Neuropsychiatric Disease and Treatment. - 1176-6328 .- 1178-2021. ; 15, s. 2049-2056
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To evaluate whether an intervention, targeting deficits in social communication, interaction and restricted activities in children and adolescents with Down syndrome and autism could lead to enhanced participation in family and school activities.Methods: The intervention included education for parents and school staff about autism, and workshops to identify social-communication and daily living activities that would be meaningful for the child to practice at home and at school. Thereafter, a three-month period of training for the child followed. Outcome measures comprised evaluation of goal achievement for each child, the Family Strain Index questionnaire and a visual scale pertaining to the parents' general opinion about the intervention.Results: On average, more than 90% of the goals were (to some extent or completely) achieved at home and at school. The mean scores of the Family Strain Index were almost identical at the follow-up to those before intervention. The evaluation supported that the use of strategies, intended to facilitate activities and communication, remained largely 18 months after start of the intervention.Conclusion: Despite the group involved in this study being composed of older children and adolescents, most of whom had severe and profound intellectual disability, the goal achievements and parents' views on the intervention were encouraging.
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