| 61. |
- Amcoff, Karin, 1975-, et al.
(författare)
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Clinical implications of assay specific differences in f-calprotectin when monitoring inflammatory bowel disease activity over time
- 2017
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Ingår i: Scandinavian Journal of Gastroenterology. - Oxon, United Kingdom : Taylor & Francis. - 0036-5521 .- 1502-7708. ; 52:3, s. 344-350
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Tidskriftsartikel (refereegranskat)abstract
- Objective: With several faecal calprotectin (FC) assays on the market, it has been difficult to define a uniform threshold for discriminating between remission and active disease in patients with inflammatory bowel disease (IBD). We aimed to compare the results of different FC-assays in IBD patients, followed over time.Material and methods: IBD patients provided faecal samples and reported clinical activity every third month prospectively over a two year period. FC was measured with two ELISA - (Bühlmann and Immunodiagnostik) and one automated fluoroimmunoassay (Phadia).Results: In total, 13 patients provided 91 faecal samples. The median (IQR) concentration of FC was higher at active disease than at remission for all assays: Bühlmann 845 (1061-226) μg/g versus 62 (224-39) μg/g, Phadia 369 (975-122) μg/g versus 11 (52-11) μg/g, and Immundiagnostik 135 (302-69) μg/g versus 8 (56-4) μg/g. The Bühlmann assay produced the largest absolute difference but the corresponding relative difference seemed to be more pronounced when analysed by the Phadia - (ratio of means 8.5; 95% CI 3.3-21.9) or the Immundiagnostik assay (ratio of means 7.4; 95% CI 3.1-17.6) than by the Bühlmann assay (ratio of means 5.3; 95% CI 2.7-10.6). Consequently, the specificity for discriminating active disease from remission varied between assays (34-75%) when the cut-off 50 μg/g was used, whereas the differences in sensitivity were less pronounced.Conclusions: Cross-comparisons revealed overall poor agreement between the assays as well as differences in the dynamics of FC. These findings suggest that standardisation of the method is needed to implement FC as a disease monitoring tool at large-scale.
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| 62. |
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| 63. |
- Amcoff, Karin, et al.
(författare)
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Prognostic significance of faecal eosinophil granule proteins in inflammatory bowel disease
- 2019
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Ingår i: Scandinavian Journal of Gastroenterology. - : Taylor & Francis. - 0036-5521 .- 1502-7708. ; 54:10, s. 1237-1244
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Tidskriftsartikel (refereegranskat)abstract
- Background: Non-invasive markers for predicting relapse would be a useful tool for the management of patients with inflammatory bowel disease. Eosinophil granulocytes and their granule proteins eosinophil cationic protein (ECP) and eosinophil-derived neurotoxin (EDN) have previously been shown to reflect disease activity in Crohn's disease and ulcerative colitis.Aim: To examine the capacity of faecal ECP and EDN to predict relapse in ulcerative colitis and Crohn's disease, and to compare these proteins with faecal calprotectin.Methods: Patients with Crohn's disease (n=49) and ulcerative colitis (n=55) were followed prospectively until relapse or end of the two-year study period. Faecal samples were obtained every third month. The predictive value of ECP and EDN was assessed in Cox regression models.Results: In ulcerative colitis, a doubled EDN or ECP concentration was associated with a 31% and 27% increased risk of relapse, respectively. EDN levels were increased both at relapse and three months prior. By contrast, in Crohn's disease, the concentration of EDN was higher among patients in remission than in those who relapsed. Correlations between faecal calprotectin, ECP and EDN were observed in both diseases.Conclusions: We demonstrate that the risk of relapse in ulcerative colitis can be predicted by consecutively measuring faecal EDN every third month, and suggest EDN as a complementary faecal marker to calprotectin to predict future relapse in ulcerative colitis. Our finding of higher EDN in Crohn's disease-patients staying in remission than in those who relapsed indicates different functions of the protein in ulcerative colitis and Crohn's disease.
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| 64. |
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| 65. |
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| 66. |
- Amouzgar, Kaveh, 1980-, et al.
(författare)
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An approach towards generating surrogate models by using RBFN with a priori bias
- 2014
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Ingår i: Proceedings of the ASME International Design Engineering Technical Conferences & Computers and Information in Engineering Conference, 2014, Vol. 2B. - New York, USA : ASME Press. - 9780791846322
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Konferensbidrag (refereegranskat)abstract
- In this paper, an approach to generate surrogate modelsconstructed by radial basis function networks (RBFN) with a prioribias is presented. RBFN as a weighted combination of radialbasis functions only, might become singular and no interpolationis found. The standard approach to avoid this is to add a polynomialbias, where the bias is defined by imposing orthogonalityconditions between the weights of the radial basis functionsand the polynomial basis functions. Here, in the proposed a prioriapproach, the regression coefficients of the polynomial biasare simply calculated by using the normal equation without anyneed of the extra orthogonality prerequisite. In addition to thesimplicity of this approach, the method has also proven to predictthe actual functions more accurately compared to the RBFNwith a posteriori bias. Several test functions, including Rosenbrock,Branin-Hoo, Goldstein-Price functions and two mathematicalfunctions (one large scale), are used to evaluate the performanceof the proposed method by conducting a comparisonstudy and error analysis between the RBFN with a priori and aposteriori known biases. Furthermore, the aforementioned approachesare applied to an engineering design problem, that ismodeling of the material properties of a three phase sphericalgraphite iron (SGI) . The corresponding surrogate models arepresented and compared
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| 67. |
- Amouzgar, Kaveh, 1980-, et al.
(författare)
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Multi-objective optimization of a disc brake system by using SPEA2 and RBFN
- 2013
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Ingår i: ASME 2013 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. - New York : ASME Press. - 9780791855898
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Many engineering design optimization problems involve multiple conflicting objectives, which today often are obtained by computational expensive finite element simulations. Evolutionary multi-objective optimization (EMO) methods based on surrogate modeling is one approach of solving this class of problems. In this paper, multi-objective optimization of a disc brake system to a heavy truck by using EMO and radial basis function networks (RBFN) is presented. Three conflicting objectives are considered. These are: 1) minimizing the maximum temperature of the disc brake, 2) maximizing the brake energy of the system and 3) minimizing the mass of the back plate of the brake pad. An iterative Latin hypercube sampling method is used to construct the design of experiments (DoE) for the design variables. Next, thermo-mechanical finite element analysis of the disc brake, including frictional heating between the pad and the disc, is performed in order to determine the values of the first two objectives for the DoE. Surrogate models for the maximum temperature and the brake energy are created using RBFN with polynomial biases. Different radial basis functions are compared using statistical errors and cross validation errors (PRESS) to evaluate the accuracy of the surrogate models and to select the most accurate radial basis function. The multi-objective optimization problem is then solved by employing EMO using the strength Pareto evolutionary algorithm (SPEA2). Finally, the Pareto fronts generated by the proposed methodology are presented and discussed.
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| 68. |
- Amouzgar, Kaveh, 1980-, et al.
(författare)
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Radial basis functions as surrogate models with a priori bias in comparison with a posteriori bias
- 2017
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Ingår i: Structural and multidisciplinary optimization (Print). - : Springer Science and Business Media LLC. - 1615-147X .- 1615-1488. ; 55:4, s. 1453-1469
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Tidskriftsartikel (refereegranskat)abstract
- In order to obtain a robust performance, the established approach when using radial basis function networks (RBF) as metamodels is to add a posteriori bias which is defined by extra orthogonality constraints. We mean that this is not needed, instead the bias can simply be set a priori by using the normal equation, i.e. the bias becomes the corresponding regression model. In this paper we demonstrate that the performance of our suggested approach with a priori bias is in general as good as, or even for many test examples better than, the performance of RBF with a posteriori bias. Using our approach, it is clear that the global response is modelled with the bias and that the details are captured with radial basis functions. The accuracy of the two approaches are investigated by using multiple test functions with different degrees of dimensionality. Furthermore, several modeling criteria, such as the type of radial basis functions used in the RBFs, dimension of the test functions, sampling techniques and size of samples, are considered to study their affect on the performance of the approaches. The power of RBF with a priori bias for surrogate based design optimization is also demonstrated by solving an established engineering benchmark of a welded beam and another benchmark for different sampling sets generated by successive screening, random, Latin hypercube and Hammersley sampling, respectively. The results obtained by evaluation of the performance metrics, the modeling criteria and the presented optimal solutions, demonstrate promising potentials of our RBF with a priori bias, in addition to the simplicity and straight-forward use of the approach.
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| 69. |
- Andell, Pontus, et al.
(författare)
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Intravascular Ultrasound Guidance Is Associated With Better Outcome in Patients Undergoing Unprotected Left Main Coronary Artery Stenting Compared With Angiography Guidance Alone
- 2017
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Ingår i: Circulation. Cardiovascular Interventions. - : Lippincott Williams & Wilkins. - 1941-7640 .- 1941-7632. ; 10:5
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Tidskriftsartikel (refereegranskat)abstract
- Background: Small observational studies have indicated better outcome with intravascular ultrasound (IVUS) guidance when performing unprotected left main coronary artery (LMCA) percutaneous coronary intervention (PCI), but the overall picture remains inconclusive and warrants further investigation. We studied the impact of IVUS guidance on outcome in patients undergoing unprotected LMCA PCI in a Swedish nationwide observational study.Methods and Results: Patients who underwent unprotected LMCA PCI between 2005 and 2014 because of stable coronary artery disease or acute coronary syndrome were included from the nationwide SCAAR (Swedish Coronary Angiography and Angioplasty Registry). Of 2468 patients, IVUS guidance was used in 621 (25.2%). The IVUS group was younger (median age, 70 versus 75 years) and had fewer comorbidities but more complex lesions. IVUS was associated with larger stent diameters (median, 4 mm versus 3.5 mm). After adjusting for potential confounders, IVUS was associated with significantly lower occurrence of the primary composite end point of all-cause mortality, restenosis, or definite stent thrombosis (hazard ratio, 0.65; 95% confidence interval, 0.50-0.84) and all-cause mortality alone (hazard ratio, 0.62; 95% confidence interval, 0.47-0.82). In 340 propensity score-matched pairs, IVUS was also associated with significantly lower occurrence of the primary end point (hazard ratio, 0.54; 95% confidence interval, 0.37-0.80).Conclusions: IVUS was associated with an independent and significant outcome benefit when performing unprotected LMCA PCI. Potential mediators of this benefit include larger and more appropriately sized stents, perhaps translating into lower risk of subsequent stent thrombosis. Although residual confounding cannot be ruled out, our findings indicate a possible hazard when performing unprotected LMCA PCI without IVUS guidance.
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| 70. |
- Andersen, Christen L., et al.
(författare)
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A phase II study of vorinostat (MK-0683) in patients with polycythaemia vera and essential thrombocythaemia
- 2013
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Ingår i: British Journal of Haematology. - : Wiley. - 0007-1048 .- 1365-2141. ; 162:4, s. 498-508
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Tidskriftsartikel (refereegranskat)abstract
- Inhibition of histone deacetylases may be an important target in patients with myeloproliferative neoplasms. This investigator-initiated, non-randomized, open-label phase II multi-centre study included 63 patients (19 essential thrombocythaemia, 44 polycythaemia vera) from 15 centres. The primary objective was to evaluate if vorinostat was followed by a decline in clonal myeloproliferation as defined by European Leukaemia Net. Thirty patients (48%) completed the intervention period (24 weeks of therapy). An intention-to-treat response rate of 35% was identified. Pruritus was resolved [19% to 0% (P=0.06)] and the prevalence of splenomegaly was lowered from 50% to 27% (P=0.03). Sixty-five per cent of the patients experienced a decrease in JAK2 V617F allele burden (P=0.006). Thirty-three patients (52% of patients) discontinued study drug before end of intervention due to adverse events (28 patients) or lack of response (5 patients). In conclusion, vorinostat showed effectiveness by normalizing elevated leucocyte and platelet counts, resolving pruritus and significantly reducing splenomegaly. However, vorinostat was associated with significant side effects resulting in a high discontinuation rate. A lower dose of vorinostat in combination with conventional and/or novel targeted therapies may be warranted in future studies.
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