| 1. |
- Oresic, Matej, 1967-, et al.
(författare)
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Dysregulation of lipid and amino acid metabolism precedes islet autoimmunity in children who later progress to type 1 diabetes
- 2008
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Ingår i: Journal of Experimental Medicine. - New York, USA : Rockefeller University Press. - 0022-1007 .- 1540-9538. ; 205:13, s. 2975-2984
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Tidskriftsartikel (refereegranskat)abstract
- The risk determinants of type 1 diabetes, initiators of autoimmune response, mechanisms regulating progress toward beta cell failure, and factors determining time of presentation of clinical diabetes are poorly understood. We investigated changes in the serum metabolome prospectively in children who later progressed to type 1 diabetes. Serum metabolite profiles were compared between sample series drawn from 56 children who progressed to type 1 diabetes and 73 controls who remained nondiabetic and permanently autoantibody negative. Individuals who developed diabetes had reduced serum levels of succinic acid and phosphatidylcholine (PC) at birth, reduced levels of triglycerides and antioxidant ether phospholipids throughout the follow up, and increased levels of proinflammatory lysoPCs several months before seroconversion to autoantibody positivity. The lipid changes were not attributable to HLA-associated genetic risk. The appearance of insulin and glutamic acid decarboxylase autoantibodies was preceded by diminished ketoleucine and elevated glutamic acid. The metabolic profile was partially normalized after the seroconversion. Autoimmunity may thus be a relatively late response to the early metabolic disturbances. Recognition of these preautoimmune alterations may aid in studies of disease pathogenesis and may open a time window for novel type 1 diabetes prevention strategies.
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| 2. |
- Tuomisto, Anne, et al.
(författare)
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A mutant collagen XIII alters intestinal expression of immune response genes and predisposes transgenic mice to develop B-cell lymphomas
- 2008
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Ingår i: Cancer Research. - : American Association for Cancer Research. - 0008-5472 .- 1538-7445. ; 68:24, s. 10324-10332
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Tidskriftsartikel (refereegranskat)abstract
- Epithelial cells of mucosal surfaces are critical for maintaining immune homeostasis by aiding in the discrimination of pathogenic and commensal microorganisms and modulating the activities of antigen-presenting cells and lymphocytes. Functional breakdowns resulting in chronic infection and inflammation are associated with the development of hematologic and solid neoplasms for which detailed pathogenetic mechanisms are poorly understood. Mice heterozygous for a transgene Col13a1(del) expressing a mutant collagen XIII developed clonal mature B-cell lineage lymphomas originating in mesenteric lymph nodes (MLN). The tumors were associated with T cells and macrophages. The incidence of disease was reduced 2-fold in transgenic mice raised under specific pathogen-free conditions, suggesting a role for infectious agents. The lymphomas did not express the mutant collagen XIII, indicating that its influence on tumorigenesis was B-cell extrinsic and likely to be associated with collagen XIII-positive tissues drained by the MLN. Studies of the small intestines of transgenic mice showed that the subepithelial basement membranes (BM) were highly abnormal and that they exhibited heightened expression of genes involved in immune responses. These results define collagen XIII-dependent maintenance of the intestinal BM as a previously unappreciated component of immune responses and a critical determinant of cancer susceptibility.
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| 3. |
- Elo, Laura L., et al.
(författare)
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Improving identification of differentially expressed genes by integrative analysis of Affymetrix and Illumina arrays
- 2006
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Ingår i: Omics. - : Mary Ann Liebert. - 1536-2310 .- 1557-8100. ; 10:3, s. 369-380
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Tidskriftsartikel (refereegranskat)abstract
- Together with the widely used Affymetrix microarrays, the recently introduced Illumina platform has become a cost-effective alternative for genome-wide studies. To efficiently use data from both array platforms, there is a pressing need for methods that allow systematic integration of multiple datasets, especially when the number of samples is small. To address these needs, we introduce a meta-analytic procedure for combining Affymetrix and Illumina data in the context of detecting differentially expressed genes between the platforms. We first investigate the effect of different expression change estimation procedures within the platforms on the agreement of the most differentially expressed genes. Using the best estimation methods, we then show the benefits of the integrative analysis in producing reproducible results across bootstrap samples. In particular, we demonstrate its biological relevance in identifying small but consistent changes during T helper 2 cell differentiation.
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| 4. |
- Elo, Laura L., et al.
(författare)
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Systematic construction of gene coexpression networks with applications to human T helper cell differentiation process
- 2007
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Ingår i: Bioinformatics. - : Oxford University Press. - 1367-4803 .- 1367-4811 .- 1460-2059. ; 23:16, s. 2096-2103
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Tidskriftsartikel (refereegranskat)abstract
- MOTIVATION: Coexpression networks have recently emerged as a novel holistic approach to microarray data analysis and interpretation. Choosing an appropriate cutoff threshold, above which a gene-gene interaction is considered as relevant, is a critical task in most network-centric applications, especially when two or more networks are being compared.RESULTS: We demonstrate that the performance of traditional approaches, which are based on a pre-defined cutoff or significance level, can vary drastically depending on the type of data and application. Therefore, we introduce a systematic procedure for estimating a cutoff threshold of coexpression networks directly from their topological properties. Both synthetic and real datasets show clear benefits of our data-driven approach under various practical circumstances. In particular, the procedure provides a robust estimate of individual degree distributions, even from multiple microarray studies performed with different array platforms or experimental designs, which can be used to discriminate the corresponding phenotypes. Application to human T helper cell differentiation process provides useful insights into the components and interactions controlling this process, many of which would have remained unidentified on the basis of expression change alone. Moreover, several human-mouse orthologs showed conserved topological changes in both systems, suggesting their potential importance in the differentiation process.SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.
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| 5. |
- Moulder, Robert, et al.
(författare)
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A comparative evaluation of software for the analysis of liquid chromatography-tandem mass spectrometry data from isotope coded affinity tag experiments
- 2005
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Ingår i: Proteomics. - : Wiley-VCH Verlagsgesellschaft. - 1615-9853 .- 1615-9861. ; 5:11, s. 2748-2760
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Tidskriftsartikel (refereegranskat)abstract
- The options available for processing quantitative data from isotope coded affinity tag (ICAT) experiments have mostly been confined to software specific to the instrument of acquisition. However, recent developments with data format conversion have subsequently increased such processing opportunities. In the present study, data sets from ICAT experiments, analysed with liquid chromatography/tandem mass spectrometry (MS/MS), using an Applied Biosystems QSTAR Pulsar quadrupole-TOF mass spectrometer, were processed in triplicate using separate mass spectrometry software packages. The programs Pro ICAT, Spectrum Mill and SEQUEST with XPRESS were employed. Attention was paid towards the extent of common identification and agreement of quantitative results, with additional interest in the flexibility and productivity of these programs. The comparisons were made with data from the analysis of a specifically prepared test mixture, nine proteins at a range of relative concentration ratios from 0.1 to 10 (light to heavy labelled forms), as a known control, and data selected from an ICAT study involving the measurement of cytokine induced protein expression in human lymphoblasts, as an applied example. Dissimilarities were detected in peptide identification that reflected how the associated scoring parameters favoured information from the MS/MS data sets. Accordingly, there were differences in the numbers of peptides and protein identifications, although from these it was apparent that both confirmatory and complementary information was present. In the quantitative results from the three programs, no statistically significant differences were observed.
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