ORCID Profile
0000-0001-9868-5033
Current Organisations
KU Leuven
,
University of Liege (GIGA)
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Publisher: Elsevier BV
Date: 12-2017
DOI: 10.1016/J.GIE.2017.09.024
Abstract: Patients with longstanding ulcerative colitis (UC) are at increased risk of developing colorectal neoplasia. Chromoendoscopy (CE) increases detection of lesions, and Kudo pit pattern classification I and II have been suggested to be predictive of benign polyps in UC. Little is known on the use of this classification in nonmagnified high-definition (HD) (virtual) CE and narrow-band Imaging (NBI) or on the interobserver agreement. The aim of this pilot study was to assess the diagnostic accuracy and the interobserver agreement of the Kudo pit pattern classification in UC patients undergoing surveillance with methylene blue CE or NBI in a multicenter study. Fifty images of lesions identified in 27 UC patients (13 neoplastic) either with classical CE (methylene blue .1% n = 24) or NBI (n = 26) were selected by an independent investigator. Images were selected from a randomized controlled trial to compare CE and NBI. All nonmagnified images were obtained with a processor and mounted in a PowerPoint file in a standardized way (same size black background). Ten endoscopists with extensive experience in NBI/CE were asked to assess the lesions for the predominant Kudo pit pattern (I, II, III Median sensitivity, specificity, negative predictive value, and positive predictive value for diagnosing neoplasia based on the presence of pit pattern other than I or II was 77%, 68%, 88%, and 46%, respectively. Diagnostic accuracy was significantly higher when a diagnosis was made with a high level of confidence (77% vs 21%, P < .001). The overall interobserver agreement for any pit pattern was only fair (κ = .282), with CE being significantly better than NBI (.322 vs .224, P < .001). From a clinical viewpoint the difference between neoplastic and non-neoplastic lesions is important. The agreement for differentiation between non-neoplastic patterns (I, II) and neoplastic patterns (III Differentiation between non-neoplastic and neoplastic pit patterns in UC lesions shows a moderate to substantial agreement among expert endoscopists. The agreement for differentiating neoplastic from non-neoplastic lesions is significantly better for NBI in comparison with HD CE. The assessment of pit pattern I or II with nonmagnified HD CE or NBI has a high negative predictive value to rule out neoplasia. (Clinical trial registration number: NCT01882205.).
Publisher: Public Library of Science (PLoS)
Date: 29-08-2012
Publisher: Springer Science and Business Media LLC
Date: 12-2005
DOI: 10.1186/1471-2156-6-S1-S115
Abstract: Due to the recent gains in the availability of single-nucleotide polymorphism data, genome-wide association testing has become feasible. It is hoped that this additional data may confirm the presence of disease susceptibility loci, and identify new genetic determinants of disease. However, the problem of multiple comparisons threatens to diminish any potential gains from this newly available data. To circumvent the multiple comparisons issue, we utilize a recently developed screening technique using family-based association testing. This screening methodology allows for the identification of the most promising single-nucleotide polymorphisms for testing without biasing the nominal significance level of our test statistic. We compare the results of our screening technique across univariate and multivariate family-based association tests. From our analyses, we observe that the screening technique, applied to different settings, is fairly consistent in identifying optimal markers for testing. One of the identified markers, TSC0047225, was significantly associated with both the ttth1 (p = 0.004) and ttth1-ttth4 (p = 0.004) phenotype(s). We find that both univariate- and multivariate-based screening techniques are powerful tools for detecting an association.
Publisher: Springer Science and Business Media LLC
Date: 05-01-2015
DOI: 10.1038/NG.3176
Publisher: Springer Science and Business Media LLC
Date: 12-2005
DOI: 10.1186/1471-2156-6-S1-S96
Abstract: Genome scans using dense single-nucleotide polymorphism (SNP) data have recently become a reality. It is thought that the increase in information content for linkage analysis as a result of the denser scans will help refine previously identified linkage regions and possibly identify new regions not identifiable using the sparser, microsatellite scans. In the context of the dense SNP scans, it is also possible to consider association strategies to provide even more information about potential regions of interest. To circumvent the multiple-testing issues inherent in association analysis, we use a recently developed strategy, implemented in PBAT, which screens the data to identify the optimal SNPs for testing, without biasing the nominal significance level. We compare the results from the PBAT analysis to that of quantitative linkage analysis on chromosome 4 using the Collaborative Study on the Genetics of Alcoholism data, as released through Genetic Analysis Workshop 14.
Publisher: Elsevier BV
Date: 02-2006
DOI: 10.1016/J.JACI.2005.10.041
Abstract: Eotaxin (chemokine, CC motif, ligand CCL11) is a potent eosinophil chemoattractant strongly implicated in the pathobiology of asthma. Genetic variation at the CCL11 locus has been correlated with serum total IgE, blood eosinophil counts, and circulating eotaxin protein levels in several case-control asthma studies. Family-based association studies of CCL11 genetic variants have not been reported to date. To evaluate 9 common CCL11 single nucleotide polymorphisms (SNPs) in nuclear families ascertained through patients with asthma participating in the Childhood Asthma Management Program study. Single nucleotide polymorphism genotyping was performed by using minisequencing and probe hybridization platforms. Family-based association analysis for asthma and 4 asthma-related intermediate quantitative phenotypes was performed by using FBAT. One SNP, -384A>G, was associated with asthma among African American families (P = .01). CCL11 SNPs and haplotypes were not associated with asthma among white or Hispanic families. Two low-frequency alleles in strong pairwise linkage disequilibrium, -426C and IVS2+199A, were associated with lower serum total IgE levels (P = .0006 and P = .009, respectively) in white families, whereas 2 more common variants, -576C and g.4438C, were associated with higher IgE levels in African American families (P = .01-.04). Haplotype analysis in the white cohort provided additional evidence of association with serum total IgE, implicating 2 haplotypes. No single SNP or haplotype associations were observed with blood eosinophil levels, FEV(1), or airway responsiveness. These findings provide further evidence that genetic variation at the CCL11 locus is an important determinant of serum total IgE levels among patients with asthma.
Publisher: Springer Science and Business Media LLC
Date: 25-08-2021
Publisher: American Thoracic Society
Date: 2006
No related grants have been discovered for Kristel Van Steen.