Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    Investigating the gut microbiota composition of individuals with attention-deficit/hyperactivity disorder and association with symptoms
    Szopinska-Tokov, Joanna ; Dam, Sarita ; Naaijen, Jilly ; Konstanti, Prokopis ; Rommelse, Nanda ; Belzer, Clara ; Buitelaar, Jan ; Franke, Barbara ; Aarts, Esther ; Vasquez, Alejandro Arias - \ 2020
    Microorganisms 8 (2020)3. - ISSN 2076-2607
    16S rRNA gene - ADHD - Gut microbiota - Inattention

    Attention-deficit/hyperactivity disorder (ADHD) is a common neurodevelopmental disorder. Given the growing evidence of gut microbiota being involved in psychiatric (including neurodevelopmental) disorders, we aimed to identify differences in gut microbiota composition between participants with ADHD and controls and to investigate the role of the microbiota in inattention and hyperactivity/impulsivity. Fecal samples were collected from 107 participants (NADHD = 42; Ncontrols = 50; NsubthreholdADHD = 15; range age: 13–29 years). The relative quantification of bacterial taxa was done using 16S ribosomal RNA gene amplicon sequencing. Beta-diversity revealed significant differences in bacterial composition between participants with ADHD and healthy controls, which was also significant for inattention, but showing a trend in case of hyperactivity/impulsivity only. Ten genera showed nominal differences (p < 0.05) between both groups, of which seven genera were tested for their association with ADHD symptom scores (adjusting for age, sex, body mass index, time delay between feces collection and symptoms assessment, medication use, and family relatedness). Our results show that variation of a genus from the Ruminococcaceae family (Ruminococcaceae_UCG_004) is associated (after multiple testing correction) with inattention symptoms and support the potential role of gut microbiota in ADHD pathophysiology.

    Planning, law and economics : The rules we make for using land
    Needham, Barrie ; Buitelaar, E. ; Hartmann, T. - \ 2018
    New York : Routledge - ISBN 9781138085572 - 180 p.
    Balans van de Leefomgeving 2018 : Nederland duurzaam vernieuwen
    Egmond, Petra van; Elzenga, Hans ; Buitelaar, Edwin ; Eerdt, Martha van; Eskinasi, Martijn ; Franken, Ron ; Gaalen, Frank van; Hanemaaijer, Aldert ; Hilbers, Hans ; Hollander, Guus de; Nijland, Hans ; Ritsema van Eck, Jan ; Ros, Jan ; Schilder, Frans ; Spoon, Martijn ; Uitbeijerse, Gabrielle ; Wouden, Ries van der; Vonk, Marijke ; Vugteveen, Pim ; Goossen, Martijn ; Blom, Wim ; Bredenoord, Hendrien ; Brink, Thelma van den; Evers, David ; Doren, Didi van; Grinsven, Hans van; Hinsberg, Arjen van; Muilwijk, Hanneke ; Oorschot, Mark van; Peeters, Jeroen ; Puijenbroek, Peter van; Raspe, Otto ; Rijn, Frank van; Schijndel, Marian van; Sluis, Sietske van der; Sorel, Niels ; Timmerhuis, Jacqueline ; Verwest, Femke ; Westhoek, Henk ; Sanders, Marlies ; Dirkx, Joep - \ 2018
    Den Haag : Planbureau voor de Leefomgeving - 284
    One World Trust (Publisher)
    Karlsson-Vinkhuyzen, Sylvia - \ 2016
    Buitelaar, Tom (2016). The challenges of the UN Secretary-General’s appointment process for the relationship with the UN Security Council. One World Trust background briefs for the 1 for 7 billion campaign. One World Trust & ACUNS (Academic Council on the United Nations System), Brief number 7, July 2016 The briefs are available at The One World Trust is grateful for the support provided by ACUNS in this effort.
    A randomized controlled pilot study into the effects of a restricted elimination diet on family structure in families with ADHD and ODD
    Pelsser, L.M. ; Steijn, D.J. van; Frankena, K. ; Toorman, J. ; Buitelaar, J.K. ; Rommelse, N.N. - \ 2013
    Child and Adolescent Mental Health 18 (2013)1. - ISSN 1475-357X - p. 39 - 45.
    deficit hyperactivity disorder - controlled-trial - children - food - community - preschool - behavior - parent
    Behavioural improvements of children with attention-deficit hyperactivity disorder (ADHD) and oppositional defiant disorder (ODD) following a restricted elimination diet (RED), may be due to concurrent changes in family environment. Methods: Twenty-four children with ADHD, were randomized to either a 5-week RED intervention, or a control intervention consisting of healthy food advices in a pilot study. Results: No differences in family environment were found, neither at baseline nor when comparing the start and end measurements of both groups. Conclusions: In this pilot study, the effects of an RED on ADHD and ODD are not mediated by improvement of family environment in families motivated to follow an RED. Replication of this preliminary study in larger groups of children is advised.
    Study into the Impact of Nutrition on Children with Attention-deficit hyperactivity disorder - ADHD (INCA Study)
    Pelser, L.M. ; Frankena, K. ; Toorman, J. ; Savelkoul, H.F.J. ; Dubios, R. ; Rodrigues Pereira, R. ; Haagen, T.A. ; Rommelse, N.N. ; Buitelaar, J.K. - \ 2012
    Wageningen UR
    attention deficit hyperactivity disorder (ADHD) - elimination diets - nutrition and health - behaviour disorders - children - child nutrition
    Protocol and data INCA trial The file INCAdata.csv contains the data collected during the INCA study (100 records with 152 variables). The data have been analysed and outcomes were published by Pelsser et al (2011): "Effects of a restricted elimination diet on the behaviour of children with attention-deficit hyperactivity disorder (INCA study): a randomised controlled trial." The Lancet 377: 494-503 (doi:10.1016/S0140-6736(10)62227-1). Further explanation of the variable abbreviations is in the file INCAvar.csv while the coding of categorical variables is in the file INCAvarcode.csv. Also the registered study protocol (see also: can be downloaded.
    ADHD, a food-induced hypersensitivity syndrome: in quest of a cause
    Pelsser, L.M. - \ 2011
    Radboud University Nijmegen. Promotor(en): J.K. Buitelaar; Huub Savelkoul, co-promotor(en): N.N. Lambregts-Rommelse. - Enschede : s.n. - ISBN 9789081768207 - 311 p.
    Effects of a restricted elimination diet on the behaviour of children with attention-deficit hyperactivity disorder (INCA study): a randomised controlled trial
    Pelsser, L.M. ; Frankena, K. ; Toorman, J. ; Savelkoul, H.F.J. ; Dubois, A.E. ; Rodrigues Pereira, R. ; Haagen, T.A. ; Rommelse, N.N. ; Buitelaar, J.K. - \ 2011
    The Lancet 377 (2011)9764. - ISSN 0140-6736 - p. 494 - 503.
    deficit/hyperactivity disorder - follow-up - food-additives - recurrent depression - oligoantigenic diet - cognitive therapy - adhd - symptoms - allergy - mta
    Background The effects of a restricted elimination diet in children with attention-deficit hyperactivity disorder (ADHD) have mainly been investigated in selected subgroups of patients. We aimed to investigate whether there is a connection between diet and behaviour in an unselected group of children. Methods The Impact of Nutrition on Children with ADHD (INCA) study was a randomised controlled trial that consisted of an open-label phase with masked measurements followed by a double-blind crossover phase. Patients in the Netherlands and Belgium were enrolled via announcements in medical health centres and through media announcements. Randomisation in both phases was individually done by random sampling. In the open-label phase (first phase), children aged 4–8 years who were diagnosed with ADHD were randomly assigned to 5 weeks of a restricted elimination diet (diet group) or to instructions for a healthy diet (control group). Thereafter, the clinical responders (those with an improvement of at least 40% on the ADHD rating scale [ARS]) from the diet group proceeded with a 4-week double-blind crossover food challenge phase (second phase), in which high-IgG or low-IgG foods (classified on the basis of every child's individual IgG blood test results) were added to the diet. During the first phase, only the assessing paediatrician was masked to group allocation. During the second phase (challenge phase), all persons involved were masked to challenge allocation. Primary endpoints were the change in ARS score between baseline and the end of the first phase (masked paediatrician) and between the end of the first phase and the second phase (double-blind), and the abbreviated Conners' scale (ACS) score (unmasked) between the same timepoints. Secondary endpoints included food-specific IgG levels at baseline related to the behaviour of the diet group responders after IgG-based food challenges. The primary analyses were intention to treat for the first phase and per protocol for the second phase. INCA is registered as an International Standard Randomised Controlled Trial, number ISRCTN 76063113. Findings Between Nov 4, 2008, and Sept 29, 2009, 100 children were enrolled and randomly assigned to the control group (n=50) or the diet group (n=50). Between baseline and the end of the first phase, the difference between the diet group and the control group in the mean ARS total score was 23·7 (95% CI 18·6–28·8; p
    Effects of food on physical and sleep complaints in children with ADHD: a randomised controlled pilot study
    Pelsser, L.M. ; Frankena, K. ; Buitelaar, J.K. ; Rommelse, N.N. - \ 2010
    European Journal of Pediatrics 169 (2010)9. - ISSN 0340-6199 - p. 1129 - 1138.
    attention-deficit/hyperactivity disorder - cognitive-behavior therapy - chronic-fatigue-syndrome - low-birth-weight - controlled-trial - oligoantigenic diet - clinical-trial - adolescents - management - multicenter
    Attention deficit/hyperactivity disorder (ADHD), a common behavioural disorder in children, may be associated with comorbid physical and sleep complaints. Dietary intervention studies have shown convincing evidence of efficacy in reducing ADHD symptoms in children. In this pilot study, we investigated the effects of an elimination diet on physical and sleep complaints in children with ADHD. A group of 27 children (3.8–8.5 years old), who all met the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria for ADHD, were assigned randomly to either a diet group (15/27) or a control group (12/27). The diet group followed a 5-week elimination diet; the control group adhered to their normal diet. Parents of both groups had to keep an extended diary and had to monitor the behaviour and the physical and sleep complaints of their child conscientiously. The primary endpoint was the clinical response, i.e. a decrease of physical and sleep complaints, at the end of the trial, based on parent ratings on a Physical Complaints Questionnaire. The number of physical and sleep complaints was significantly decreased in the diet group compared to the control group (p¿
    Response to 'Lack of studies investigating the association of childhood eczema, sleeping problems and attention-deficit/hyperactivity disorder' letter by J. Schmitt and M. Romanos
    Pelsser, L. ; Buitelaar, J. ; Savelkoul, H.F.J. - \ 2009
    Pediatric Allergy and Immunology 20 (2009)3. - ISSN 0905-6157 - p. 301 - 301.
    Is ADHD een (niet-)allergische overgevoeligheid? Een hypothese
    Pelsser, L. ; Buitelaar, J. ; Savelkoul, H.F.J. - \ 2009
    Nederlands Tijdschrift voor Allergie 9 (2009)3. - ISSN 1568-2498 - p. 86 - 92.
    Onderzoeksresultaten naar het causale verband tussen ‘Attention-deficit hyperactivity disorder’ (ADHD) en allergieën zijn niet eenduidig. Allergieën zoals astma en eczeem zijn klinische syndromen waarbij zowel genetische aanleg als omgevingsfactoren (huisdieren, huisstofmijten, pollen en voeding) kunnen bijdragen tot de ontwikkeling ervan. De hypothese dat ADHD bij sommige kinderen ook een allergie kan zijn, wordt onderbouwd aan de hand van de verschillende mechanismen die ten grondslag liggen aan zowel ADHD als allergische aandoeningen. Volgens de geaccepteerde terminologie voor allergie voldoet ADHD aan de criteria van overgevoeligheid, allergie en atopie. Deze hypothese zal in gerandomiseerd gecontroleerd onderzoek getoetst moeten worden. Hierbij moet niet alleen gebruik gemaakt worden van immunologisch onderzoek, maar ook van genetisch onderzoek. Dit omdat genen die gerelateerd worden aan het immuunsysteem met ADHD geassocieerd kunnen worden. Immunotherapeutische benaderingen, zoals immunotherapie en probiotica, zouden betrokken kunnen worden bij de behandeling van ADHD. Wanneer overgevoeligheid voor omgevingsfactoren, zoals voedingsmiddelen, bijdraagt aan het manifest worden van ADHD, zal de diagnostiek en de behandeling van ADHD herzien moeten worden, om zo de kwaliteit van zorg voor deze patiënten te verbeteren.
    ADHD as a (non) allergic hypersensitivity disorder : A hypothesis
    Pelsser, L. ; Buitelaar, J. ; Savelkoul, H.F.J. - \ 2009
    Pediatric Allergy and Immunology 20 (2009)2. - ISSN 0905-6157 - p. 107 - 112.
    attention-deficit/hyperactivity disorder - deficit hyperactivity disorder - controlled-trial - hyperkinetic syndrome - revised nomenclature - oligoantigenic diet - atopic-dermatitis - food allergy - double-blind - children
    Research data concerning the causal association between attention deficit hyperactivity disorder (ADHD) and allergies are conflicting. Allergic disorders, like asthma and eczema are clinical syndromes in which both genetic predisposition and environmental factors (pets, pollen and foods) contribute to its development. The hypothesis of ADHD, in some children also being an allergic disorder, is postulated based on comparison of the mechanisms underlying the development of ADHD and allergic disorders. According to the accepted terminology, ADHD may comply with the criteria of hypersensitivity, allergy and atopy. This hypothesis has to be thoroughly tested by randomized controlled trials using environmental triggers and immunologic research. As genes related to the immune system may be associated with ADHD, further genetic research is compulsory. Immunotherapeutic approaches, using immunotherapy and probiotics, can subsequently be implicated in the treatment of ADHD. If hypersensitivity to environmental stimuli like foods contributes to the development of ADHD, the assessment and treatment of ADHD will have to be reconsidered, thereby improving the quality of care for these patients.
    A randomised controlled trial into the effects of food and ADHD
    Pelsser, L. ; Frankena, K. ; Toorman, J. ; Savelkoul, H.F.J. ; Rodrigues Pereira, R. ; Buitelaar, J. - \ 2009
    European Child & Adolescent Psychiatry 18 (2009)1. - ISSN 1018-8827 - p. 12 - 19.
    attention-deficit/hyperactivity disorder - cognitive-behavior therapy - chronic-fatigue-syndrome - oligoantigenic diet - hyperactive boys - double-blind - children - additives - adolescents - multicenter
    The aim of this study is to assess the efficacy of a restricted elimination diet in reducing symptoms in an unselected group of children with Attention deficit/hyperactivity disorder (ADHD). Dietary studies have already shown evidence of efficacy in selected subgroups. Twenty-seven children (mean age 6.2) who all met the DSM-IV criteria for ADHD, were assigned randomly to either an intervention group (15/27) or a waiting-list control group (12/27). Primary endpoint was the clinical response, i.e. a decrease in the symptom scores by 50% or more, at week 9 based on parent and teacher ratings on the abbreviated ten-item Conners Scale and the ADHD-DSM-IV Rating Scale. The intention-to-treat analysis showed that the number of clinical responders in the intervention group was significantly larger than that in the control group [parent ratings 11/15 (73%) versus 0/12 (0%); teacher ratings, 7/10 (70%) versus 0/7 (0%)]. The Number of ADHD criteria on the ADHD Rating Scale showed an effect size of 2.1 (cohen¿s d) and a scale reduction of 69.4%. Comorbid symptoms of oppositional defiant disorder also showed a significantly greater decrease in the intervention group than it did in the control group (cohens¿s d 1.1, scale reduction 45.3%). A strictly supervised elimination diet may be a valuable instrument in testing young children with ADHD on whether dietary factors may contribute to the manifestation of the disorder and may have a beneficial effect on the children¿s behaviour.
    Protocol 06PRT/7719: A study to the impact of nutrition on children with ADHD (INCA study): a Dutch randomised controlled trial into the effects of food on the behaviour of a random group of school-going children meeting the DSM-IV criteria for ADHD, including immunological testing
    Pelsser, L. ; Savelkoul, H.F.J. ; Buitelaar, J. - \ 2007
    The Lancet (2007). - ISSN 0140-6736 - 2 p.
    Ecological profiles of rare and endemic species
    Holmgren, M. ; Poorter, L. ; Siepel, A. ; Bongers, F.J.J.M. ; Buitelaar, M. ; Chatelain, C. ; Gautier, L. ; Hawthorne, W.D. ; Helmink, A.T.F. ; Jongkind, C.C.H. ; Os Breijer, H.J. van; Wieringa, J.J. ; Zoest, A.R. van - \ 2004
    In: Biodiversity of West African forests; an ecological atlas of woody plant species / Poorter, L., Bongers, F.J.J.M., Kouamé, F.Y.N., Hawthorne, W.D., Wallingford (UK) : CABI Publishing - ISBN 9780851997346 - p. 101 - 389.
    The fungal biocontrol agent Coniothyrium minitans: production by solid-state fermentation, application and marketing
    Vrije, T. de; Antoine, N. ; Buitelaar, R.M. ; Oostra, J. ; Rinzema, A. ; Weber, F.J. - \ 2001
    Applied Microbiology and Biotechnology 56 (2001). - ISSN 0175-7598 - p. 58 - 68.
    Biological control agents (BCAs) are potential alternatives for the chemical fungicides presently used in agriculture to fight plant diseases. Coniothyrium minitans is an example of a promising fungal BCA. It is a naturally occurring parasite of the fungus Sclerotinia sclerotiorum, a wide-spread pathogen which substantially reduces the yield of many crops. This review describes, exemplified by C. minitans, the studies that need to be carried out before a fungal BCA is successfully introduced into the market. The main aspects considered are the biology of C. minitans, the development of a product by mass production of spores using solid-state fermentation technology, its biocontrol activity and marketing of the final product.
    Growth and sporulation stoichiometry and kinetics of coniothyrium minitans on agar media
    Ooijkaas, L.P. ; Buitelaar, R.M. ; Tramper, J. ; Rinzema, A. - \ 2000
    Biotechnology and Bioengineering 69 (2000)3. - ISSN 0006-3592 - p. 292 - 300.
    Coniothyrium minitans was cultivated on agar media with different concentrations of starch, urea, and trace elements. By means of elemental balances, the stoichiometry of growth and sporulation was established. C. minitans produced byproducts on all media, especially in the medium with high urea concentrations, where 30␘f the starch was converted into byproducts. Simple empirical models were used to describe the kinetics of growth, sporulation, CO2 production, and substrate consumption on all media. Total biomass and mycelium could be described reasonably well with the logistic law. Starch, urea, and oxygen consumption and CO2 production could be described as a function of total biomass by the linear-growth model of Pirt. There were almost no differences between media for the estimates of yield coefficients and maintenance coefficients. Only at high urea concentrations were maintenance coefficients much higher. Similar to substrate consumption and CO2 production, the kinetics of sporulation could be described as a function of mycelium production with the linear-growth model. It is shown that sporulation of C. minitans is growth-associated. Based on kinetics, the process costs for producing spores are roughly calculated. In addition, it is shown that fermentor costs represent the majority of production costs
    Defined media and inert supports : their potential as solid-state fermentation production systems
    Ooijkaas, L.P. ; Weber, F.J. ; Buitelaar, R.M. ; Tramper, J. ; Rinzema, A. - \ 2000
    Trends in Biotechnology 18 (2000)8. - ISSN 0167-7799 - p. 356 - 360.
    Solid-state fermentation (SSF) using inert supports impregnated with chemically defined liquid media has several potential applications in both scientific studies and in the industrial production of high-value products, such as metabolites, biological control agents and enzymes. As a result of its more defined system, SSF on inert supports offers numerous advantages, such as improved process control and monitoring, and enhanced process consistency, compared with cultivation on natural solid substrates. Copyright (C) 2000 Elsevier Science Ltd.
    Fungal biopesticide production by solid-state fermentation : growth and sporulation of Coniothyrium minitans
    Ooijkaas, L.P. - \ 2000
    Agricultural University. Promotor(en): J. Tramper; R.M. Buitelaar; A. Rinzema. - S.l. : S.n. - ISBN 9789058081681 - 120
    paraconiothyrium minitans - biopesticiden - fermentatie - sporulatie - groei - paraconiothyrium minitans - microbial pesticides - fermentation - sporulation - growth

    The use of an inert carrier impregnated with a chemically defined medium might be attractive in industrial processes. This system can be used as alternative for agricultural substrates such as grains in solid-state fermentation for the production of fungal biopesticides. During recent years, the use of fungal spores for the biological control of plant pests and diseases has received increasing interest. Coniothyrium minitans is a biocontrol agent of Sclerotinia sclerotiorum a widespread plant pathogen affecting more than 360 plant species. As with other biopesticides, large quantities of effective spores of C. minitans are needed. An SSF process seems the preferred mass production method for this fungus. However, rational design and operation of an SSF-process for mass production of fungal conidia are hampered by several factors. One of them is the lack of knowledge about the physiology and the kinetics of fungal growth and sporulation in SSF.

    In this thesis, research on the physiology and kinetics of growth and sporulation of C. minitans in SSF is described. The aim was to determine the optimal substrate composition for spore production and to determine the kinetic parameters and stoichiometry of the bioconversion reactions. The quantity of biomass is an essential variable in characterizing the optimal growth and sporulation conditions. However, direct measurement of biomass is almost impossible in SSF since fungi penetrate into and bind tightly to the solid substrate. Therefore, various indirect methods to estimate the amount of biomass, being respiration measurements and several biochemical analyses, were first evaluated for C. minitans .

    Secondly, the influence of the main medium components, carbon and nitrogen, was studied in more detail using chemically defined media, which facilitate reproducible studies. Several nitrogen sources in combination with glucose or starch were evaluated for their influence on sporulation of C. minitans. The medium with the combination of nitrogen and carbon source giving the best results was further optimized with respect to spore quantity using statistically based experimental designs. These designs are more efficient than varying one factor at a time. This optimization strategy allowed the spore production to be increased by a factor 7 from 4*10 9to almost 3*10 10spores per Petri dish of 9-cm diameter. These numbers correspondes with a spore production of 2*10 8to 3*10 -1medium.

    Thirdly, the stoichiometry and kinetics of mycelium and spore production were studied on defined media with different concentrations of starch, urea and trace elements. By means of elemental balances the stoichiometry of growth and sporulation was established. Based on the kinetics, the process costs for producing spores were roughly calculated. It was shown that fermentor costs form the major part of the production costs.

    In all these laboratory studies the use of a chemically defined medium was very useful. It facilitates reproducible and detailed physiological and kinetic studies in SSF, which will eventually be the basis for efficient process development, control strategies and reactor design. The use of an inert carrier impregnated with a chemically defined medium, as alternative for agricultural substrates in SSF, might be attractive in industrial processes too. The industrial potential of inert carriers impregnated with chemically defined medium for the production of spores of C. minitans and other (high-added-value) products is finally discussed.

    Medium optimization for spore production of coniothyrium minitans using statistically-based experimental designs
    Ooijkaas, L.P. ; Wilkinson, E.C. ; Tramper, J. ; Buitelaar, R.M. - \ 1999
    Biotechnology and Bioengineering 64 (1999)1. - ISSN 0006-3592 - p. 92 - 100.
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