M De Vos

Carl von Ossietzky Universität Oldenburg, Oldenburg, Lower Saxony, Germany

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Publications (268)1041.16 Total impact

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    ABSTRACT: Introduction Microscopic bowel inflammation is present in up to 50% of patients with spondyloarthritis (SpA) and is associated with more severe disease. Currently no reliable biomarkers exist to identify patients at risk. Calprotectin is a sensitive marker of neutrophilic inflammation, measurable in serum and stool. Objectives To assess whether serum and faecal calprotectin in addition to C-reactive protein (CRP) can be used to identify patients with SpA at risk of microscopic bowel inflammation. Methods Serum calprotectin and CRP were measured in 125 patients with SpA. In 44 of these patients, faecal samples were available for calprotectin measurement. All 125 patients underwent an ileocolonoscopy to assess the presence of microscopic bowel inflammation. Results Microscopic bowel inflammation was present in 53 (42.4%) patients with SpA. Elevated serum calprotectin and CRP were independently associated with microscopic bowel inflammation. Faecal calprotectin was also significantly higher in patients with microscopic bowel inflammation. Patients with CRP and serum calprotectin elevated had a frequency of bowel inflammation of 64% vs 25% in patients with low levels of both. When either CRP or serum calprotectin was elevated, the risk was intermediate (40%) and measuring faecal calprotectin provided further differentiation. Hence we suggest a screening approach where initially serum calprotectin and CRP are assessed and, if necessary, faecal calprotectin. The model using this scenario provided an area under the ROC curve of 74.4% for detection of bowel inflammation. Conclusions Calprotectin measurements in stool and serum, in addition to CRP, may provide a promising strategy to identify patients with SpA at risk of bowel inflammation and could play a role in overall patient stratification.
    No preview · Article · Dec 2015 · Annals of the rheumatic diseases
  • R. Zink · B. Hunyadi · S. Van Huffel · M. De Vos
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    ABSTRACT: The analysis of mobile EEG Brain Computer Interface (BCI) recordings can benefit from unsupervised learning methods. Removing the calibration phase allows for faster and shorter interactions with a BCI and could potentially deal with non-stationarity issues in the signal quality. Here we present a data-driven approach based on a trilinear decomposition, Canonical Polyadic Decomposition (CPD), applied to an auditory BCI dataset. Different ways to construct a data-tensor for this purpose and how the results can be interpreted are explained. We also discuss current limitations in terms of trial identification and model initialization. The results of the new analysis are shown to be comparable to those of the traditional supervised stepwise LDA approach.
    No preview · Article · Jul 2015

  • No preview · Article · Jun 2015 · Acta gastro-enterologica Belgica
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    ABSTRACT: Colonoscopy is an important endoscopic examination for the diagnosis and treatment of pathological conditions of the colon, like polyps and colorectal cancer. However, several factors determine the quality of colonoscopy and thus the quality of polyp and colorectal cancer detection. The Flemish Society of Gastroenterology (VVGE) performed a voluntary on-line registry among its members to identify quality of colonoscopy in Flanders, Belgium. 64 gastroenterologists voluntarily registered 4276 consecutive colonoscopies performed during a 3 month study period. Colonoscopy quality indicators were prospectively collected and analysed. Results showed a low voluntary participation rate (17%), acceptable overall adenoma detection rate of 20,5% and colorectal cancer interval rate of 5,4%. Complications were low (perforation 0,1% and major bleeding 1,5%). The current study showed that in Flanders, Belgium on-line registration of colonoscopy quality indicators is feasible and that quality of colonoscopy in daily practice meets the expectations of (inter)national guidelines. However, further improvement of the registry and an open debate on the quality control of colonoscopy in Flanders is warranted (Belgian Registry B30020096548). Copyright© Acta Gastro-Enterologica Belgica.
    No preview · Article · Jun 2015 · Acta gastro-enterologica Belgica
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    ABSTRACT: Background Microscopic bowel inflammation is present in about 50% of spondyloarthritis (SpA) patients. Although subclinical, it appears to be a prognostic factor in SpA, linked with more extensive disease and a less favorable outcome. At this moment, however, reliable biomarkers are missing. The calgranulins S100A8/S100A9 and S100A12 are very sensitive markers of innate immune activation. They are released from monocytes and granulocytes in the early phase of the immune response and exert prominent pro-inflammatory effects via Toll-like receptor 4 dependent mechanisms. Calgranulins can be measured in serum and stool. Moreover, the S100A8/S100A9 heterodimer, also called calprotectin, has been established for a long time as a fecal marker of disease activity in inflammatory bowel disease. Objectives To assess whether calgranulins can be used as biomarkers for microscopic bowel inflammation in SpA. Methods Serum calgranulin levels were measured in 122 newly diagnosed SpA patients and 39 healthy controls. SpA patients underwent an ileocolonoscopy to assess the presence of microscopic bowel inflammation. Bowel biopsies were histologically scored and subsequently immuno-stained for S100A8 and S100A9. Results Serum levels of S100A8/S100A9 and S100A12 were significantly higher in SpA patients versus healthy controls (p<0.001). Levels correlated moderately with CRP, but not with ASDAS, BASDAI or swollen joint count. SpA patients with the acute type of microscopic gut inflammation (N=23) had significantly higher calgranulin levels compared to those with normal gut histology (N=62) (p=0.025 for S100A8/S100A9 and p=0.040 for S100A12). Furthermore, immunohistology showed high staining of S100A8 and S100A9 on acutely inflamed bowel biopsies, compared to absent/minimal staining on normal biopsies. Importantly, NSAID intake had neither influence on immunohistology nor on serum measurements. Additionally, we found that having both an elevated CRP together with an elevated S100A8/S100A9 increased the odds of having microscopic bowel inflammation with a factor of 5.4. Conclusions Calgranulin levels, both systemically and locally, reflected the presence of acute microscopic bowel inflammation in SpA. These results also illustrate the high sensitivity of calgranulins, as they detected inflammation present only on a subclinical level. Their measurements can provide a way to identify those patients in whom further invasive checkup might be useful, as endoscopic screening of all SpA patients is not feasible in daily clinical practice. Calgranulins are therefore the first surrogate markers for subclinical bowel inflammation in SpA, allowing for more individually tailored diagnostic and therapeutic decision making. Acknowledgements The research leading to these results has received funding from the European Union's 7th Framework Program under EC-GA No. 305266 “MIAMI”. Disclosure of Interest None declared
    No preview · Article · Jun 2015 · Annals of the Rheumatic Diseases
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    ABSTRACT: Genome-wide association studies of the related chronic inflammatory bowel diseases (IBD) known as Crohn's disease and ulcerative colitis have shown strong evidence of association to the major histocompatibility complex (MHC). This region encodes a large number of immunological candidates, including the antigen-presenting classical human leukocyte antigen (HLA) molecules. Studies in IBD have indicated that multiple independent associations exist at HLA and non-HLA genes, but they have lacked the statistical power to define the architecture of association and causal alleles. To address this, we performed high-density SNP typing of the MHC in >32,000 individuals with IBD, implicating multiple HLA alleles, with a primary role for HLA-DRB1∗01:03 in both Crohn's disease and ulcerative colitis. Noteworthy differences were observed between these diseases, including a predominant role for class II HLA variants and heterozygous advantage observed in ulcerative colitis, suggesting an important role of the adaptive immune response in the colonic environment in the pathogenesis of IBD.
    Full-text · Article · Jan 2015 · Nature Genetics

  • No preview · Article · Jan 2015 · Acta gastro-enterologica Belgica
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    ABSTRACT: This study discusses a technique to correct for effects of electrode grid displacement across serial surface EMG measurements with high-density electrode arrays (HDsEMG). A proof of concept study shows that automated correction is possible and that agreement is increased between the same motor unit action potentials observed across different measurements. It also shows great potential for assisting motor unit tracking studies, indicating that otherwise electrode displacements cannot always be precisely described.
    Full-text · Article · Nov 2014 · Methods of Information in Medicine
  • W. Swinnen · B. Hunyadi · E. Acar · S.V. Huffe · M. De Vos
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    ABSTRACT: EEG-fMRI research to study brain function became popular because of the complementarity of the modalities. Through the use of data-driven approaches such as jointICA, sources extracted from EEG can be linked to regions in fMRI. Joint-ICA in its standard formulation however does not allow for the inclusion of multiple EEG electrodes, so it is a rather arbitrary choice which electrode is used in the analysis. In this study, we explore several ways to include the higher dimensionality of the EEG during a joint decomposition of EEG and fMRI. Our results show that incorporation of multiple channels in the jointICA can reveal new relations between fMRI activation maps and ERP features.
    No preview · Article · Nov 2014
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    C Zich · S Debener · M De Vos · C Kranczioch · I Gutberlet
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    ABSTRACT: The aims of this contribution were (1) to investigate the feasibility of motor imagery (MI) electroencephalogram (EEG)-based online feedback during continuous functional magnetic resonance imaging, and (2) to examine the validity of electric MI signatures by comparing EEG MI data obtained inside and outside the MRI scanner. Participants (N=22) imagined hand movements, which led to an event-related desynchronization (ERD) of the contralateral sensorimotor rhythm. The contralateral ERD of the online corrected as well as of the offline corrected EEG data correlated strongly with the EEG data recorded outside the MRI scanner. We provide a proof-of-principle demonstration that meaningful EEG-based feedback inside the MRI scanner is possible for MI.
    Full-text · Conference Paper · Sep 2014
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    ABSTRACT: Background The safety of anti-tumour necrosis factor (TNF) agents during pregnancy is a major concern for child-bearing women and physicians.AimTo assess the impact of anti-TNF therapy on adverse pregnancy and foetal outcomes in women with inflammatory bowel disease (IBD).Methods Pregnancies occurring during anti-TNF treatment or less than 3 months after its cessation in IBD patients followed in GETAID centres were recorded from January 2009 to December 2010. Ninety-nine pregnancies in women without anti-TNF treatment were identified from the CESAME registry. We compared pregnancy and neonatal outcomes by a case–control study.ResultsIn the 124 IBD patients followed, 133 pregnancies were reported. At the conception time, 23% of patients had active disease. Eighty-eight per cent (n = 117) of the 133 pregnancies followed until delivery resulted in 118 liveborns (one twin pregnancy). Complications were observed in 47 (35%) women and 24 (20%) newborns. In multivariate analysis, factors associated with pregnancy complications were: current smoking (P = 0.004), a B2 (stenotic) phenotype in CD women (P = 0.004), occurrence of a flare during pregnancy (P = 0.006) and a past history of complicated pregnancy (P = 0.007). Current smoking was the only factor associated with severe (i.e. potentially lethal) pregnancy complications (P = 0.02). Having IBD for more than 10 years prior to conception was associated with newborn complications (P = 0.007). No difference was found with the control group for any of the pregnancy and neonatal outcomes.Conclusion In our series, the safety profile of anti-TNF therapy during pregnancy and the neonatal period appears similar to control group of IBD women not treated with anti-TNF therapy.
    Full-text · Article · Jun 2014 · Alimentary Pharmacology & Therapeutics
  • S. Debener · M. De Vos

    No preview · Article · Jun 2014
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    C. Zich · M. De Vos · C. Kranczioch · S. Debener

    Full-text · Article · Jun 2014 · Clinical Neurophysiology
  • C. Snauwaert · M. De Vos · D. De Looze
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    ABSTRACT: Small bowel diverticular disease is rare and mainly involves the duodenum, followed by the jejunum and the ileum. Complications from jejunal diverticular disease, particularly haemorrhage, are clinically challenging for its diagnosis and management. With the increased awareness of this disorder and the improvement and development of new diagnostic tools, such as a capsule endoscopy and a double-balloon enteroscopy, reported cases are increasing. In this manuscript, a case study of a 66-year-old man presenting with massive gastrointestinal bleeding which could be attributed to a jejunal diverticulum after numerous endoscopic and radiological examinations, is reported. Jejunal diverticular bleeding is a challenging cause of severe gastrointestinal bleeding with high historical mortality rates. The advent of the small-bowel endoscopy offers the opportunity for a better diagnosis and treatment, thereby avoiding surgery.
    No preview · Article · Jun 2014

  • No preview · Article · Feb 2014

  • No preview · Article · Feb 2014 · Journal of Crohn s and Colitis

  • No preview · Article · Feb 2014 · Journal of Crohn s and Colitis
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    T Holvoet · M De Vos · F Baert
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    ABSTRACT: Ferriprieve anemie is een vaak voorkomende pathologie waarvan de diagnose door een problema-tische interpretatie van de ijzerparameters niet altijd gemakkelijk te stellen is. De laatste jaren zijn er nieuwe inzichten in de fysiologie van het ijzermetabolisme, met de ontdekking van het hepcidine-eiwit als belangrijkste voorbeeld. In dit artikel wordt er een overzicht gegeven van de huidige kennis over het ijzermetabolisme, van waaruit op een doeltreffende wijze de diagnose van ferriprieve ane-mie kan worden gesteld. Daarnaast is er de laatste jaren meer evidentie ontstaan voor een vroeg-tijdige rol van intraveneuze ijzersubstitutie bij ferriprieve anemie, die de transfusies kan beperken en op een snelle en duurzame manier de anemie kan corrigeren. Inleiding Ijzertekort is een van de belangrijkste oorzaken van anemie en wereldwijd verantwoordelijk voor onge-veer 50% van de gevallen van bloedarmoede. Men schat dat ongeveer 4% van de mannelijke bevolking en 11% van de vrouwen een belangrijk ijzertekort heeft en globaal 1% à 2% van de volwassenen aan ferriprieve anemie lijdt. Deze cijfers stijgen sterk met de leeftijd zodat ongeveer 12% van de bejaarden in meerdere of mindere mate anemisch is door ijzer-tekort (1). Ferriprieve anemie uit zich vaak door vage klachten van vermoeidheid, algemene zwakte en hoofdpijn, maar soms ook door haarverlies en ontsteking van de mondhoek (angulaire stomatitis). Deze klachten zijn eerder aspecifiek en kunnen zich onder andere ook voordoen bij ernstige ferripriviteit zonder anemie. Een groot deel van de patiënten zal echter asymptomatisch zijn. Zeldzamere manifestaties van ferripriviteit zijn pica (zin in zaken die niet geschikt zijn als voedsel, bv. klei), pagofagie (pica voor ijs) en het plassen van rode urine na het eten van bieten (bieturie). Daarnaast is ijzergebrek vaak geassocieerd aan het " restless legs "-syndroom, dat negen keer vaker voorkomt bij patiënten met ijzertekort (2-4). Hoewel het ziektebeeld vaak voorkomt, is de diagnose van ijzertekort niet altijd eenvoudig te stellen, o.a. door moeilijkheden bij het interpreteren van de ijzerparameters. De laatste jaren zijn er nieuwe inzichten verworven in de pathofysiologie van het ijzermetabolisme die belangrijk kunnen zijn voor de diagnostiek. Daarnaast zijn er een aantal nieuwe intraveneuze ijzerpreparaten beschikbaar die de behandeling van ferriprieve anemie in belangrijke mate veranderd hebben. Dit artikel biedt een over-zicht van de optimale diagnostische strategie en de behandeling van ferriprieve anemie.
    Full-text · Article · Jan 2014 · Tijdschrift voor Geneeskunde
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    ABSTRACT: The automated analysis of the EEG pattern of the preterm newborn would be a valuable tool in the neonatal intensive care units for the prognosis of neurological development. The analysis of the (a)symmetry between the two hemispheres can provide useful information about neuronal dysfunction in early stages. Consecutive and subgroup analyses of different brain regions will allow detecting physiologic asymmetry versus pathologic asymmetry. This can improve the assessment of the long-term neurodevelopmental outcome. We show that pathological asymmetry can be measured and detected using the channel symmetry index, which comprises the difference in power spectral density of contralateral EEG signals. To distinguish pathological from physiological normal EEG patterns, we make use of one-class SVM classifiers.
    No preview · Article · Jan 2014
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    ABSTRACT: De intestinale microflora 6 spelen een belangrijke rol in de homeostase van het menselijke lichaam. Er bestaat toenemende evidentie dat een onevenwicht in deze darmmicrobiota een aandeel heeft in het ontstaan van verschillende gastro-intestinale en systemische ziektebeelden zoals antibioticageas-socieerde diarree, inflammatoir darmlijden (IBD), functioneel darmlijden en obesitas. Het herstellen van dit bacteriële onevenwicht zou dan ook therapeutische toepassingen kunnen hebben. De probiotica 7 werden in dit opzicht uitvoerig onderzocht, maar slaagden er niet in om een blijvende verandering in de microbiota te veroorzaken. Een transplantatie van fecale microbiota (FMT), waarbij men fecale micro-biota van een gezonde persoon transplanteert naar een zieke patiënt, kan daarentegen wel een gun-stig therapeutisch effect hebben. In dit artikel wordt er een overzicht gegeven van hoe een dergelijke transplantatie in de praktijk wordt uitgevoerd en wat de evidentie is voor de toepassing in verschillende ziektebeelden. Van alle indicaties bestaat de meeste evidentie voor het gebruik bij recidiverende Clostri-dium difficile-infecties, waarbij de techniek duidelijk betere resultaten boekt dan een behandeling met antibiotica. Voor andere ziektebeelden zijn de gegevens schaarser en is meer onderzoek noodzakelijk. Het blijft echter een veelbelovende techniek en een " hot topic " in de hedendaagse gastro-enterologie.
    Full-text · Article · Jan 2014 · Tijdschrift voor Geneeskunde

Publication Stats

5k Citations
1,041.16 Total Impact Points


  • 2011-2014
    • Carl von Ossietzky Universität Oldenburg
      • Department of Psychology
      Oldenburg, Lower Saxony, Germany
    • Universitair Ziekenhuis Leuven
      Louvain, Flanders, Belgium
  • 1976-2014
    • Universitair Ziekenhuis Ghent
      • • Department of Gastroenterology
      • • Department of Rheumatology
      Gand, Flemish, Belgium
  • 1974-2014
    • Ghent University
      • • Gastroenterology
      • • Department of Internal Medicine
      • • Department of Pathology
      • • Rheumatology
      Gand, Flanders, Belgium
  • 2007-2011
    • University of Leuven
      • Department of Electrical Engineering (ESAT)
      Louvain, Flanders, Belgium
    • Radboud University Nijmegen
      • Department of Radiology
      Nymegen, Gelderland, Netherlands
  • 2003
    • Free University of Brussels
      • Department of Gastroenterology
      Brussels, BRU, Belgium