28 results on '"Bakker AM"'
Search Results
2. Contribution of Fcgamma receptor IIIA gene 158V/F polymorphism and copy number variation to the risk of ACPA-positive rheumatoid arthritis.
- Author
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Thabet MM, Huizinga TW, Marques RB, Stoeken-Rijsbergen G, Bakker AM, Kurreeman FA, White SJ, Toes RE, and van der Helm-van Mil AH
- Published
- 2009
- Full Text
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3. Extent of acute hydrocephalus after aneurysmal subarachnoid hemorrhage as a risk factor for delayed cerebral infarction.
- Author
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Bakker AM, Mees SM, Algra A, Rinkel GJ, Bakker, Annelies M, Dorhout Mees, Sanne M, Algra, Ale, and Rinkel, Gabriël J E
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- 2007
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4. Parents of childhood cancer survivors: a descriptive look at their concerns and needs.
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Leventhal-Belfer L, Bakker AM, and Russo CL
- Published
- 1993
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5. Sudden cardiac arrest in infants and children: proposal for a diagnostic workup to identify the etiology. An 18-year multicenter evaluation in the Netherlands.
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Bakker AM, Albrecht M, Verkaik BJ, de Jonge RCJ, Buysse CMP, Blom NA, Rammeloo LAJ, Verhagen JMA, Riedijk MA, Yap SC, Tan HL, and Kammeraad JAE
- Subjects
- Infant, Humans, Child, Child, Preschool, Adolescent, Young Adult, Adult, Retrospective Studies, Netherlands epidemiology, Death, Sudden, Cardiac etiology, Death, Sudden, Cardiac prevention & control, Arrhythmias, Cardiac complications, Myocarditis, Heart Diseases, Cardiomyopathies complications
- Abstract
Sudden cardiac arrest (SCA) studies are often population-based, limited to sudden cardiac death, and excluding infants. To guide prevention opportunities, it is essential to be informed of pediatric SCA etiologies. Unfortunately, etiologies frequently remain unresolved. The objectives of this study were to determine paediatric SCA etiology, and to evaluate the extent of post-SCA investigations and to assess the performance of previous cardiac evaluation in detecting conditions predisposing to SCA. In a retrospective cohort (2002-2019), all children 0-18 years with out-of-hospital cardiac arrest (OHCA) referred to Erasmus MC Sophia Children's Hospital or the Amsterdam UMC (tertiary-care university hospitals), with cardiac or unresolved etiologies were eligible for inclusion. SCA etiologies, cardiac and family history and etiologic investigations in unresolved cases were assessed. The etiology of arrest could be determined in 52% of 172 cases. Predominant etiologies in children ≥ 1 year (n = 99) were primary arrhythmogenic disorders (34%), cardiomyopathies (22%) and unresolved (32%). Events in children < 1 year (n = 73) were largely unresolved (70%) or caused by cardiomyopathy (8%), congenital heart anomaly (8%) or myocarditis (7%). Of 83 children with unresolved etiology a family history was performed in 51%, an autopsy in 51% and genetic testing in 15%. Pre-existing cardiac conditions presumably causative for SCA were diagnosed in 9%, and remained unrecognized despite prior evaluation in 13%., Conclusion: SCA etiology remained unresolved in 83 of 172 cases (48%) and essential diagnostic investigations were often not performed. Over one-fifth of SCA patients underwent prior cardiac evaluation, which did not lead to recognition of a cardiac condition predisposing to SCA in all of them. The diagnostic post-SCA approach should be improved and the proposed standardized pediatric post-SCA diagnostics protocol may ensure a consistent and systematic evaluation process increasing the diagnostic yield., What Is Known: • Arrests in infants remain unresolved in most cases. In children > 1 year, predominant etiologies are primary arrhythmia disorders, cardiomyopathy and myocarditis. • Studies investigating sudden cardiac arrest are often limited to sudden cardiac death (SCD) in 1 to 40 year old persons, excluding infants and successfully resuscitated children., What Is New: • In patients with unresolved SCA events, the diagnostic work up was often incompletely performed. • Over one fifth of victims had prior cardiac evaluation before the arrest, with either a diagnosed cardiac condition (9%) or an unrecognized cardiac condition (13%)., (© 2023. The Author(s).)
- Published
- 2024
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6. Enlarging the Arsenal of Test Species for Sediment Quality Assessment.
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Wieringa N, Droge STJ, Bakker AM, Melkert RA, Prast BJ, Verdonschot PFM, and Kraak MHS
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- Animals, Insecta, Geologic Sediments, Biological Assay, Water Pollutants, Chemical toxicity, Water Pollutants, Chemical analysis, Chironomidae
- Abstract
Since only a few standard benthic test species are available for sediment quality, our study aimed to employ multiple test species representing different sensitivity categories in the quality assessment of contaminated sediments. To this end three macroinvertebrate species, Sericostoma personatum (caddisfly, sensitivity category 10), Asellus aquaticus (isopod, category 3) and Chironomus riparius (chironomid, category 2), were exposed to sediments originating from various contamination sources in whole sediment bioassays using intact sediment cores. The agricultural sediment caused insect mortality, the agricultural and urban sediment caused isopod growth reduction and the urban and Wastewater Treatment Plant (WWTP) sediment affected chironomid emergence time. It is concluded that the arsenal of standard species can be successfully expanded by non-standard species, reducing over- or underestimation of the risks of contaminated sediments., (© 2023. The Author(s).)
- Published
- 2023
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7. Benchmarking computational methods for B-cell receptor reconstruction from single-cell RNA-seq data.
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Andreani T, Slot LM, Gabillard S, Strübing C, Reimertz C, Yaligara V, Bakker AM, Olfati-Saber R, Toes REM, Scherer HU, Augé F, and Šimaitė D
- Abstract
Multiple methods have recently been developed to reconstruct full-length B-cell receptors (BCRs) from single-cell RNA sequencing (scRNA-seq) data. This need emerged from the expansion of scRNA-seq techniques, the increasing interest in antibody-based drug development and the importance of BCR repertoire changes in cancer and autoimmune disease progression. However, a comprehensive assessment of performance-influencing factors such as the sequencing depth, read length or number of somatic hypermutations (SHMs) as well as guidance regarding the choice of methodology is still lacking. In this work, we evaluated the ability of six available methods to reconstruct full-length BCRs using one simulated and three experimental SMART-seq datasets. In addition, we validated that the BCRs assembled in silico recognize their intended targets when expressed as monoclonal antibodies. We observed that methods such as BALDR, BASIC and BRACER showed the best overall performance across the tested datasets and conditions, whereas only BASIC demonstrated acceptable results on very short read libraries. Furthermore, the de novo assembly-based methods BRACER and BALDR were the most accurate in reconstructing BCRs harboring different degrees of SHMs in the variable domain, while TRUST4, MiXCR and BASIC were the fastest. Finally, we propose guidelines to select the best method based on the given data characteristics., (© The Author(s) 2022. Published by Oxford University Press on behalf of NAR Genomics and Bioinformatics.)
- Published
- 2022
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8. Do pain management apps use evidence-based psychological components? A systematic review of app content and quality.
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MacPherson M, Bakker AM, Anderson K, and Holtzman S
- Abstract
Background: With hundreds of pain management apps on the Canadian marketplace, it can be challenging for patients and clinicians to select effective and evidence-based mobile health (mHealth) apps that address pain from a biopsychosocial perspective., Aims: The aim of this study is to identify pain management apps within the Canadian app marketplaces to aid clinicians in recommending apps., Methods: The iOS and Android marketplaces were systematically searched to identify pain management apps that included at least one core component of cognitive behavioral therapy (CBT) or mindfulness- and acceptance-based therapies. Selected apps were assessed using a researcher developed psychological components checklist, and the Mobile App Rating Scale (MARS). These two measures provided a robust assessment of the apps' technical abilities and psychological principles being implemented., Results: Five hundred eight pain management apps were identified, yet only 12 included a psychological component and were available for evaluation. On average, apps contained 8.10 out of 18 psychological components (SD = 2.77) with a MARS quality rating of 4.02 out of 5 (SD = 0.32). The most common psychological components were grounded in CBT, including psychoeducation, sleep hygiene, behavioral activation, coping skills training, and social support. Among the least commonly included components were goal setting, values, and culture/diversity. Two-thirds of the apps involved health care practitioners in their development, but independent scientific review of apps was scarce., Conclusion: The highest scoring apps (Curable, Pathways, Vivify) are highlighted for health care practitioners who may wish to recommend mHealth technologies to their patients for pain management. Future directions for research and app development are discussed., Competing Interests: No potential conflict of interest was reported by the authors., (© 2022 The Author(s). Published with license by Taylor & Francis Group, LLC.)
- Published
- 2022
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9. Complement component C1q is produced by isolated articular chondrocytes.
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Lubbers R, van Schaarenburg RA, Kwekkeboom JC, Levarht EWN, Bakker AM, Mahdad R, Monteagudo S, Cherifi C, Lories RJ, Toes REM, Ioan-Facsinay A, and Trouw LA
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- Animals, Cartilage, Articular cytology, Collagen Type II genetics, Collagen Type X genetics, Gene Expression Regulation, Humans, Mice, Osteoarthritis, Knee metabolism, Pilot Projects, Chondrocytes metabolism, Complement C1q genetics, Complement C1r genetics, Complement C1s genetics, Osteoarthritis, Knee genetics, RNA, Messenger metabolism
- Abstract
Objective: Inflammation and innate immune responses may contribute to development and progression of Osteoarthritis (OA). Chondrocytes are the sole cell type of the articular cartilage and produce extracellular-matrix molecules. How inflammatory mediators reach chondrocytes is incompletely understood. Previous studies have shown that chondrocytes express mRNA encoding complement proteins such as C1q, suggesting local protein production, which has not been demonstrated conclusively. The aim of this study is to explore C1q production at the protein level by chondrocytes., Design: We analysed protein expression of C1q in freshly isolated and cultured human articular chondrocytes using Western blot, ELISA and flow cytometry. We examined changes in mRNA expression of collagen, MMP-1 and various complement genes upon stimulation with pro-inflammatory cytokines or C1q. mRNA expression of C1 genes was determined in articular mouse chondrocytes., Results: Primary human articular chondrocytes express genes encoding C1q, C1QA, C1QB, C1QC, and secrete C1q to the extracellular medium. Stimulation of chondrocytes with pro-inflammatory cytokines upregulated C1QA, C1QB, C1QC mRNA expression, although this was not confirmed at the protein level. Extracellular C1q bound to the chondrocyte surface dose dependently. In a pilot study, binding of C1q to chondrocytes resulted in changes in the expression of collagens with a decrease in collagen type 2 and an increase in type 10. Mouse articular chondrocytes also expressed C1QA, C1QB, C1QC, C1R and C1S at the mRNA level., Conclusions: C1q protein can be expressed and secreted by human articular chondrocytes and is able to bind to chondrocytes influencing the relative collagen expression., (Copyright © 2019 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.)
- Published
- 2020
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10. [Periorbital, blue tumour in newborn twins].
- Author
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Bakker AM, Hartwig NG, and Kamerbeek A
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- Cysts congenital, Diseases in Twins congenital, Humans, Infant, Newborn, Lacrimal Apparatus Diseases congenital, Cysts diagnosis, Diseases in Twins diagnosis, Lacrimal Apparatus Diseases diagnosis
- Abstract
Newborn twins both had a blue, smooth tumour in the inner angle of the orbit; one of them had two such tumours. They were diagnosed with congenital dacryocystoceles. If decompression into the nose is not effective, patients should undergo probing early in life to reduce the incidence of dacryocystitis and orbital cellulitis.
- Published
- 2018
11. Functional and phenotypical analysis of IL-6-secreting CD4 + T cells in human adipose tissue.
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de Jong AJ, Pollastro S, Kwekkeboom JC, Andersen SN, Dorjée AL, Bakker AM, Alzaid F, Soprani A, Nelissen RGHH, Mullers JB, Venteclef N, de Vries N, Kloppenburg M, Toes REM, and Ioan-Facsinay A
- Subjects
- Aged, CD4-Positive T-Lymphocytes classification, Female, Humans, Immunophenotyping, In Vitro Techniques, Male, Middle Aged, Osteoarthritis, Knee immunology, Osteoarthritis, Knee pathology, Phenotype, Receptors, Antigen, T-Cell, alpha-beta metabolism, T-Lymphocyte Subsets immunology, Adipose Tissue cytology, Adipose Tissue immunology, CD4-Positive T-Lymphocytes immunology, Interleukin-6 metabolism
- Abstract
Emerging evidence indicates that a dynamic interplay between the immune system and adipocytes contributes to the disturbed homeostasis in adipose tissue of obese subjects. Recently, we observed IL-6-secretion by CD4
+ T cells from the stromal vascular fraction (SVF) of the infrapatellar fat pad (IFP) of knee osteoarthritis patients directly ex vivo. Here we show that human IL-6+ CD4+ T cells from SVF display a more activated phenotype than the IL-6- T cells, as evidenced by the expression of the activation marker CD69. Analysis of cytokines secretion, as well as expression of chemokine receptors and transcription factors associated with different Th subsets (Treg, Th1, Th2, Th17 and Tfh) revealed that IL-6-secreting CD4+ T cells cannot be assigned to a conventional Th subset. TCRβ gene analysis revealed that IL-6+ and IL-6- CD4+ T cells appear clonally unrelated to each other, suggesting a different specificity of these cells. In line with these observations, adipocytes are capable of enhancing IL-6 production by CD4+ T cells. Thus, IL-6+ CD4+ T cells are TCRαβ T cells expressing an activated phenotype potentially resulting from an interplay with adipocytes that could be involved in the inflammatory processes in the OA joint., (© 2017 The Authors. European Journal of Immunology published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)- Published
- 2018
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12. [A child with abdominal pain and fever: consider acute lobar nephritis - diagnostic considerations when the appendix is invisible on ultrasound].
- Author
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Bakker AM, Vijgen GHEJ, Hartwig NG, and Tramper-Stranders GA
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- Abdominal Abscess diagnosis, Abdominal Abscess etiology, Abdominal Pain etiology, Acute Disease, Appendicitis diagnosis, Appendix diagnostic imaging, Child, Child, Preschool, Diagnosis, Differential, Fever etiology, Humans, Kidney pathology, Magnetic Resonance Imaging, Male, Nephritis complications, Ultrasonography methods, Nephritis diagnosis
- Abstract
Acute lobar nephritis (ALN) is a focal interstitial bacterial infection of the renal parenchyma. ALN is described as a midpoint between an acute pyelonephritis and renal abscess. ALN is underdiagnosed in children due to both non-specific symptoms and negative urinalysis/bacteriuria laboratory findings. The gold standard for diagnosis of ALN is CT scanning, however MRI can be considered to avoid radiation exposure. Diagnosing ALN is relevant, because it requires prolonged antibiotic treatment. Insufficient antibiotic treatment could cause renal scarring and subsequent hypertension or renal failure. Outpatient follow-up is indicated to exclude congenital urogenital abnormalities. We describe two paediatric patients with acute abdominal pain and fever who were suspected to have appendicitis (appendix not visualised by ultrasonography), but eventually were diagnosed with ALN and a renal abscess (despite absence of pyuria). These reports serve to highlight the issues around the recognition and diagnosis of ALN in children, and the need for clinicians to be mindful of this condition.
- Published
- 2018
13. Emotion Dysregulation and Social Support in PTSD and Depression: A Study of Trauma-Exposed Veterans.
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Cox DW, Bakker AM, and Naifeh JA
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- Adult, Canada, Depression diagnosis, Emotions, Female, Humans, Male, Middle Aged, Psychiatric Status Rating Scales, Self Report, Stress Disorders, Post-Traumatic diagnosis, Stress Disorders, Post-Traumatic therapy, Depression psychology, Social Support, Stress Disorders, Post-Traumatic psychology, Veterans psychology
- Abstract
Emotion dysregulation has been associated with impaired interpersonal functioning and increased risk of posttraumatic psychopathology. Given that social support is a robust predictor of psychiatric morbidity following trauma exposure, we examined whether emotion dysregulation was associated with posttraumatic psychopathology through its negative effect on social support. Using self-report data from 90 military veterans (89.9% men) enrolled in an outpatient psychotherapy program for posttraumatic stress disorder (PTSD), we found that social support partially mediated the effect of emotion dysregulation on PTSD (P
M = .10) and depression symptoms (PM = .14). When source of support was considered, friend (PM = .08) and significant other support (PM = .06) were greater mediators of the effect of emotion dysregulation on depression symptoms than family support (PM = .01). There were no differential mediating effects for support providers on PTSD symptoms. Our findings indicate that social support is a statistically significant yet clinically limited mechanism through which emotion dysregulation is linked with psychiatric symptoms. Implications for these limitations and alternative potentially relevant interpersonal mechanisms are discussed., (Copyright © 2017 International Society for Traumatic Stress Studies.)- Published
- 2017
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14. A novel long non-coding RNA in the rheumatoid arthritis risk locus TRAF1-C5 influences C5 mRNA levels.
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Messemaker TC, Frank-Bertoncelj M, Marques RB, Adriaans A, Bakker AM, Daha N, Gay S, Huizinga TW, Toes RE, Mikkers HM, and Kurreeman F
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- Alpha-Amanitin pharmacology, Arthritis, Rheumatoid metabolism, Arthritis, Rheumatoid pathology, Cell Line, Tumor, DNA, Intergenic metabolism, Fibroblasts cytology, Fibroblasts drug effects, Genetic Loci, Genotype, Hepatocytes cytology, Hepatocytes drug effects, Hepatocytes metabolism, Humans, Monocytes cytology, Monocytes drug effects, Monocytes metabolism, Nucleic Acid Synthesis Inhibitors pharmacology, Polymorphism, Single Nucleotide, Primary Cell Culture, RNA, Long Noncoding antagonists & inhibitors, RNA, Long Noncoding metabolism, RNA, Messenger antagonists & inhibitors, RNA, Messenger metabolism, RNA, Small Interfering genetics, RNA, Small Interfering metabolism, Synovial Membrane cytology, Synovial Membrane drug effects, Synovial Membrane metabolism, Transcription, Genetic drug effects, Arthritis, Rheumatoid genetics, DNA, Intergenic genetics, Fibroblasts metabolism, Genetic Predisposition to Disease, RNA, Long Noncoding genetics, RNA, Messenger genetics
- Abstract
Long non-coding RNAs (lncRNAs) can regulate the transcript levels of genes in the same genomic region. These locally acting lncRNAs have been found deregulated in human disease and some have been shown to harbour quantitative trait loci (eQTLs) in autoimmune diseases. However, lncRNAs linked to the transcription of candidate risk genes in loci associated to rheumatoid arthritis (RA) have not yet been identified. The TRAF1 and C5 risk locus shows evidence of multiple eQTLs and transcription of intergenic non-coding sequences. Here, we identified a non-coding transcript (C5T1lncRNA) starting in the 3' untranslated region (UTR) of C5. RA-relevant cell types express C5T1lncRNA and RNA levels are further enhanced by specific immune stimuli. C5T1lncRNA is expressed predominantly in the nucleus and its expression correlates positively with C5 mRNA in various tissues (P=0.001) and in peripheral blood mononuclear cells (P=0.02) indicating transcriptional co-regulation. Knockdown results in a concurrent decrease in C5 mRNA levels but not of other neighbouring genes. Overall, our data show the identification of a novel lncRNA C5T1lncRNA that is fully located in the associated region and influences transcript levels of C5, a gene previously linked to RA pathogenesis.
- Published
- 2016
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15. Toll-like receptor triggering augments activation of human mast cells by anti-citrullinated protein antibodies.
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Suurmond J, Rivellese F, Dorjée AL, Bakker AM, Rombouts YJ, Rispens T, Wolbink G, Zaldumbide A, Hoeben RC, Huizinga TW, and Toes RE
- Subjects
- Antigen-Antibody Complex immunology, Arthritis, Rheumatoid immunology, Cells, Cultured, Cytokines biosynthesis, Gene Expression Regulation immunology, Humans, Immunoglobulin G immunology, Ligands, Osteoarthritis immunology, RNA, Messenger genetics, Receptors, IgG immunology, Synovial Membrane immunology, Toll-Like Receptors genetics, Toll-Like Receptors immunology, Mast Cells immunology, Peptides, Cyclic immunology, Toll-Like Receptors biosynthesis
- Abstract
Objective: Mast cells may play a role in rheumatoid arthritis (RA), but activation of human mast cells in autoimmune settings has been little studied. Toll-like receptors (TLR) and Fcγ receptors (FcγR) are important receptors for cellular activation in the joint, but expression and stimulation of these receptors in human mast cells or the functional interplay between these pathways is poorly understood. Here, we analysed triggering of human mast cells via these receptors in the context of anti-citrullinated protein antibody-positive (ACPA+) RA., Methods: RNA and protein expression of TLRs and FcγR was quantified using PCR and flow cytometry, respectively. Mast cells were stimulated with TLR ligands (including HSP70) combined with IgG immune complexes and IgG-ACPA., Results: Human mast cells expressed TLRs and produced cytokines in response to TLR ligands. Both cultured and synovial mast cells expressed FcγRIIA, and triggering of this receptor by IgG immune complexes synergised with activation by TLR ligands, leading to two- to fivefold increased cytokine levels. Mast cells produced cytokines in response to ACPA immune complexes in a citrulline-specific manner, which synergised in the presence of HSP70., Conclusions: Our data show that synovial mast cells express FcγRIIA and that mast cells can be activated by IgG-ACPA and TLR ligands. Importantly, combined stimulation via TLRs and immune complexes leads to synergy in cytokine production. These findings suggest mast cells are important targets for TLR ligands and immune complexes, and that combined activation of mast cells via these pathways greatly enhances inflammation in synovial tissue of RA patients., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.)
- Published
- 2015
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16. Activation of human basophils by combined toll-like receptor- and FcεRI-triggering can promote Th2 skewing of naive T helper cells.
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Suurmond J, Stoop JN, Rivellese F, Bakker AM, Huizinga TW, and Toes RE
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- Basophils metabolism, Cell Differentiation genetics, Cell Differentiation immunology, Chemokine CCL5 genetics, Chemokine CCL5 immunology, Chemokine CCL5 metabolism, Humans, Immunoglobulin E genetics, Immunoglobulin E immunology, Immunoglobulin E metabolism, Interleukins genetics, Interleukins immunology, Interleukins metabolism, Leukotrienes genetics, Leukotrienes immunology, Leukotrienes metabolism, Ligands, RNA, Messenger genetics, RNA, Messenger immunology, Receptors, IgE metabolism, Th2 Cells metabolism, Toll-Like Receptors metabolism, Basophils immunology, Receptors, IgE genetics, Receptors, IgE immunology, Th2 Cells immunology, Toll-Like Receptors genetics, Toll-Like Receptors immunology
- Abstract
Basophils are mostly known for their involvement in allergic reactions. Recent studies in mice indicate a role for basophils in the induction of adaptive immunity, especially T helper 2 (Th2) responses. Therefore, it would be highly important to understand how basophils respond to pathogen-associated molecules, such as ligands for toll-like receptors (TLRs), and if the basophils could promote Th2 responses via these stimuli. To this end, the activation of basophils via TLRs in combination with activation via IgE was studied, as well as its effect on T helper cell skewing. Using quantitative PCR, we demonstrated the presence of mRNA for TLRs 1-8 in human basophils. Basophils responded to TLR triggering with differential cytokine production, but not with degranulation. Simultaneous triggering of TLRs and IgE led to synergy in production of IL-4, IL-8, IL-13, and RANTES. Furthermore, the synergistic effects on basophils mediated by IgE and TLR-4 triggering allowed robust Th2 skewing upon activation of naïve human CD4⁺ T cells. Our data show that human basophils respond to TLR ligands in synergy with IgE-mediated activation and that the cytokines produced can promote Th2 differentiation. These results indicate a role for basophils in the regulation of T-cell responses in humans., (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)
- Published
- 2014
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17. Genetic variation of the Fc gamma receptor 3B gene and association with rheumatoid arthritis.
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Marques RB, Thabet MM, White SJ, Houwing-Duistermaat JJ, Bakker AM, Hendriks GJ, Zhernakova A, Huizinga TW, van der Helm-van Mil AH, and Toes RE
- Subjects
- Base Sequence, Case-Control Studies, Chromosomes, Human, Pair 1, DNA Primers, Gene Dosage, Humans, Molecular Sequence Data, Polymerase Chain Reaction, Sequence Homology, Nucleic Acid, Arthritis, Rheumatoid genetics, Genetic Variation, Receptors, IgG genetics
- Abstract
Background: Fc gamma receptors (FcγRs) play a crucial role in immunity by linking IgG antibody-mediated responses with cellular effector and regulatory functions. Genetic variants in these receptors have been previously identified as risk factors for several chronic inflammatory conditions. The present study aimed to investigate the presence of copy number variations (CNVs) in the FCGR3B gene and its potential association with the autoimmune disease rheumatoid arthritis (RA)., Methodology/principal Findings: CNV of the FCGR3B gene was studied using Multiplex Ligation Dependent Probe Amplification (MLPA) in 518 Dutch RA patients and 304 healthy controls. Surprisingly, three independent MLPA probes targeting the FCGR3B promoter measured different CNV frequencies, with probe#1 and #2 measuring 0 to 5 gene copies and probe#3 showing little evidence of CNV. Quantitative-PCR correlated with the copy number results from MLPA probe#2, which detected low copy number (1 copy) in 6.7% and high copy number (≥3 copies) in 9.4% of the control population. No significant difference was observed between RA patients and the healthy controls, neither in the low copy nor the high copy number groups (p-values = 0.36 and 0.71, respectively). Sequencing of the FCGR3B promoter region revealed an insertion/deletion (indel) that explained the disparate CNV results of MLPA probe#1. Finally, a non-significant trend was found between the novel -256A>TG indel and RA (40.7% in healthy controls versus 35.9% in RA patients; P = 0.08)., Conclusions/significance: The current study highlights the complexity and poor characterization of the FCGR3B gene sequence, indicating that the design and interpretation of genotyping assays based on specific probe sequences must be performed with caution. Nonetheless, we confirmed the presence of CNV and identified novel polymorphisms in the FCGR3B gene in the Dutch population. Although no association was found between RA and FCGR3B CNV, the possible protective effect of the -256A>TG indel polymorphism must be addressed in larger studies.
- Published
- 2010
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18. Immunomodulatory dendritic cells inhibit Th1 responses and arthritis via different mechanisms.
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van Duivenvoorde LM, Han WG, Bakker AM, Louis-Plence P, Charbonnier LM, Apparailly F, van der Voort EI, Jorgensen C, Huizinga TW, and Toes RE
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- Adoptive Transfer, Animals, Cells, Cultured, Collagen Type II administration & dosage, Collagen Type II immunology, Dendritic Cells drug effects, Dexamethasone pharmacology, Male, Mice, Mice, Inbred BALB C, Mice, Inbred DBA, Mice, Transgenic, Th1 Cells metabolism, Arthritis, Experimental immunology, Arthritis, Experimental prevention & control, Dendritic Cells immunology, Dendritic Cells transplantation, Immune Tolerance drug effects, Th1 Cells immunology
- Abstract
Dendritic cells (DCs) are professional APCs which have the unique ability to present both foreign and self-Ags to T cells and steer the outcome of immune responses. Because of these characteristics, DCs are attractive vehicles for the delivery of therapeutic vaccines. Fully matured DCs are relatively well-defined and even used in clinical trials in cancer. DCs also have the potential to influence the outcome of autoimmunity by modulating the underlying autoimmune response. To gain a better appreciation of the abilities and mechanisms by which immunomodulatory DCs influence the outcome of T cell responses, we studied several immunomodulatory DCs (TNF-, IL-10-, or dexamethasone-stimulated bone marrow-derived DCs) side by side for their ability to modulate T cell responses and autoimmune diseases. Our data show that these differentially modulated DCs display a different composition of molecules involved in T cell activation. Although, all DC subsets analyzed were able to inhibit the induction of collagen-induced arthritis, the modulation of the underlying immune response was different. Vaccination with TNF- or IL-10-modulated DCs altered the Th1/Th2 balance as evidenced by the induction of IL-5- and IL-10-secreting T cells and the concomitant reduction of the IgG2a-IgG1 ratio against the immunizing Ag. In contrast, DCs modulated with dexamethasone did not affect the ratio of IL-5-producing vs IFN-gamma-producing T cells and tended to affect the Ab response in a nonspecific manner. These data indicate that distinct mechanisms can be used by distinct DC subsets to change the outcome of autoimmunity.
- Published
- 2007
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19. Expression of FOXP3 mRNA is not confined to CD4+CD25+ T regulatory cells in humans.
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Morgan ME, van Bilsen JH, Bakker AM, Heemskerk B, Schilham MW, Hartgers FC, Elferink BG, van der Zanden L, de Vries RR, Huizinga TW, Ottenhoff TH, and Toes RE
- Subjects
- Animals, CD4-Positive T-Lymphocytes immunology, DNA-Binding Proteins immunology, Forkhead Transcription Factors, Gene Expression Regulation immunology, Humans, Interferon-gamma immunology, Interferon-gamma metabolism, Jurkat Cells, Leukocytes, Mononuclear immunology, Lymphocyte Activation immunology, Lymphocyte Activation physiology, Mice, Mycobacterium leprae metabolism, RNA, Messenger immunology, RNA, Messenger metabolism, Receptors, Interleukin-2, T-Lymphocytes immunology, CD4-Positive T-Lymphocytes metabolism, DNA-Binding Proteins biosynthesis, Gene Expression Regulation physiology, Leukocytes, Mononuclear metabolism, T-Lymphocytes metabolism
- Abstract
Expression of the transcription factor Foxp3 (forkhead box P3) has been implicated as a key element for CD25(+) T regulatory cell function in mice. However, literature over similar involvement of FOXP3 expression in human T regulatory cells is limited. We found that, unlike murine cells, FOXP3 mRNA expression could be induced in human CD25(-) and CD8(+) peripheral blood mononuclear cells, which were both negative for FOXP3 mRNA expression after isolation. Expression of FOXP3 mRNA began as soon as 24-40 hours after stimulation, demonstrating a correlation between activation and FOXP3 mRNA expression in human cells. In order to determine whether FOXP3 expression is confined to CD4(+)CD25(+) T cells with a regulatory phenotype, we analyzed several well-defined T-cell clones and lines with various specificities. Surprisingly, expression of FOXP3 mRNA was detected in all clones and limited to the CD25(hi) populations. Nonetheless, the CD25(hi) fraction did not display regulatory properties because both the CD25(hi) and CD25(low) populations exhibited a similar proliferative- and interferon-gamma-secreting potential after antigenic stimulation. These results indicate that FOXP3 expression in humans, unlike mice, may not be specific for cells with a regulatory phenotype and may be only a consequence of activation status.
- Published
- 2005
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20. Functional regulatory immune responses against human cartilage glycoprotein-39 in health vs. proinflammatory responses in rheumatoid arthritis.
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van Bilsen JH, van Dongen H, Lard LR, van der Voort EI, Elferink DG, Bakker AM, Miltenburg AM, Huizinga TW, de Vries RR, and Toes RE
- Subjects
- Adipokines, Adult, Aged, Autoantigens, CD4-Positive T-Lymphocytes immunology, Case-Control Studies, Cell Communication immunology, Chitinase-3-Like Protein 1, Female, Humans, Lectins, Male, Middle Aged, Th1 Cells immunology, Arthritis, Rheumatoid immunology, Glycoproteins immunology, Immunity, Cellular, Inflammation immunology
- Abstract
The class of immune response against autoantigens could profoundly influence the onset and/or outcome of autoimmune diseases. Until now, there is only limited information on the antigen-specific balance between proinflammatory and regulatory responses in humans. Here we analyzed the natural immune response against a candidate autoantigen in rheumatoid arthritis, human cartilage glycoprotein-39 (HC gp-39). Peripheral blood mononuclear cells from healthy individuals reacted against HC gp-39 with the production of IL-10 but not IFN-gamma. Ex vivo assays indicated that the naturally occurring HC gp-39-specific immune response in bulk is powerful enough to suppress antigen-specific recall responses, demonstrating that rather than being unresponsive, the HC gp-39-directed immune response in healthy individuals shows a strong bias toward a regulatory phenotype. Moreover, CD4(+) T cell lines directed against HC gp-39 expressed CD25, glucocorticoid-induced tumor necrosis factor receptor, and Foxp3 molecules and were capable of suppressing antigen-specific T cell responses. Cell-cell contact was required for this suppression. As opposed to healthy individuals, the HC gp-39-directed immune response in 50% of patients with rheumatoid arthritis exhibits polarization toward a proinflammatory T helper 1 phenotype and is significantly less powerful in suppressing antigen-specific recall responses. Together these findings indicate that the presence of HC gp-39-specific immune responses in healthy individuals may have an inhibitory effect on inflammatory responses in areas where HC gp-39 is present. Furthermore, these data indicate that the class of HC gp-39-directed immune response in rheumatoid arthritis patients has shifted from an antiinflammatory toward a proinflammatory phenotype.
- Published
- 2004
- Full Text
- View/download PDF
21. Allele-specific expression of the IL-1 alpha gene in human CD4+ T cell clones.
- Author
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Bayley JP, van Rietschoten JG, Bakker AM, van Baarsen L, Kaijzel EL, Wierenga EA, van der Pouw Kraan TC, Huizinga TW, and Verweij CL
- Subjects
- Arthritis, Rheumatoid genetics, Arthritis, Rheumatoid immunology, Clone Cells, Deoxyribonucleases, Type II Site-Specific genetics, Genotype, Humans, Polymorphism, Restriction Fragment Length, Reverse Transcriptase Polymerase Chain Reaction, Th1 Cells immunology, Th1 Cells metabolism, Th2 Cells immunology, Th2 Cells metabolism, Alleles, CD4-Positive T-Lymphocytes immunology, CD4-Positive T-Lymphocytes metabolism, Gene Expression Regulation immunology, Interleukin-1 biosynthesis, Interleukin-1 genetics
- Abstract
A number of reports have described the monoallelic expression of murine cytokine genes. Here we describe the monoallelic expression of the human IL-1alpha gene in CD4+ T cells. Analysis of peripheral blood T cell clones derived from healthy individuals revealed that the IL-1alpha gene shows predominantly monoallelic expression. Monoallelic expression was observed in Th0, Th1, and Th2 cell clones. In addition, we demonstrate monoallelic expression in T cell clones from rheumatoid arthritis patients derived from synovial fluid of the knee joint, suggesting that the occurrence of this phenomenon is not different from that in clones derived from healthy individuals. The finding of monoallelic expression of a cytokine gene in human CD4+ T cell clones provides evidence for allele-specific silencing/activation as another layer of regulation of IL-1alpha gene expression.
- Published
- 2003
- Full Text
- View/download PDF
22. Association of polymorphisms of the tumour necrosis factor receptors I and II and rheumatoid arthritis.
- Author
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Bayley JP, Bakker AM, Kaijzel EL, Huizinga TW, and Verweij CL
- Subjects
- Antigens, CD genetics, Arthritis, Rheumatoid diagnostic imaging, Arthritis, Rheumatoid immunology, Arthrography, Case-Control Studies, Chronic Disease, Disease Susceptibility, Female, Humans, Netherlands, Polymorphism, Restriction Fragment Length, Receptors, Tumor Necrosis Factor, Type I, Arthritis, Rheumatoid genetics, Polymorphism, Genetic, Receptors, Tumor Necrosis Factor genetics
- Abstract
Objective: To assess the role of polymorphisms of the tumour necrosis factor (TNF) receptors, TNF-RI (p55) and TNF-RII (p75) in the susceptibility to and severity of rheumatoid arthritis (RA) in Dutch patients., Methods: A total of 319 consecutive RA patients, and a cohort of 90 female RA patients with detailed 12-yr follow-up were genotyped for the TNF-RI exon 1 (+36 A to G) and TNF-RII 3' UTR (+1690 T to C) polymorphisms., Results: The frequencies of the TNF-RI and TNF-RII polymorphisms were determined in both patient groups and healthy controls, but no significant differences were found. To determine the relationship of these polymorphisms to disease severity, the extent of joint damage in the cohort of 90 female RA patients was analysed. No differences in severity were observed., Conclusion: These TNF-RI and TNF-RII polymorphisms were not found to be associated with susceptibility to or severity of RA in the Dutch population.
- Published
- 2003
- Full Text
- View/download PDF
23. Analysis of allelic expression patterns of IL-2, IL-3, IL-4, and IL-13 in human CD4+ T cell clones.
- Author
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Bayley JP, Bakker AM, Kaijzel EL, Wierenga EA, van der Pouw-Kraan TC, Huizinga TW, and Verweij CL
- Subjects
- Alleles, Animals, Base Sequence, Clone Cells, Gene Expression, Genotype, Heterozygote, Humans, Interleukin-13 genetics, Interleukin-2 genetics, Interleukin-3 genetics, Interleukin-4 genetics, Mice, Polymorphism, Genetic, Polymorphism, Single Nucleotide, CD4-Positive T-Lymphocytes immunology, Interleukins genetics
- Abstract
The occurrence of monoallelic expression of cytokine genes in single cells has been convincingly demonstrated, but there have been few reports of this phenomenon in T cell clones. Here we describe studies on the expression of alleles of the human genes encoding IL-2, IL-3, IL-4, and IL-13 in human CD4(+) T cell clones. In contrast to the results reported in mouse T cell clones and single human T cells, we found no evidence for the monoallelic expression of the IL-2, IL-3, and IL-13 genes. The gene for IL-4 showed an imbalance in expression from each allele, indicating differential expression of IL-4 alleles within or between IL-4-expressing cells.
- Published
- 2003
- Full Text
- View/download PDF
24. Role of tumor necrosis factor-alpha and interleukin-10 promoter gene polymorphisms in leprosy.
- Author
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Santos AR, Suffys PN, Vanderborght PR, Moraes MO, Vieira LM, Cabello PH, Bakker AM, Matos HJ, Huizinga TW, Ottenhoff TH, Sampaio EP, and Sarno EN
- Subjects
- Adolescent, Adult, Aged, Alleles, Female, Gene Frequency, Humans, Interleukin-10 metabolism, Male, Middle Aged, Tumor Necrosis Factor-alpha metabolism, Interleukin-10 genetics, Leprosy genetics, Polymorphism, Genetic, Promoter Regions, Genetic genetics, Tumor Necrosis Factor-alpha genetics
- Abstract
Single-nucleotide polymorphisms within the genes coding for tumor necrosis factor (TNF)-alpha and interleukin (IL)-10 have been associated with several infectious diseases. To determine whether such polymorphisms are associated with leprosy, genotyping was performed at the -308 and -238 positions of the promoter of the TNF-alpha gene in 210 and 191 patients with multibacillary (MB) leprosy, respectively; 90 and 79 patients with paucibacillary (PB) leprosy; and 92 control subjects. For the -592 and -819 positions within the promoter of the IL-10 gene, 143 patients with MB leprosy, 79 patients with PB leprosy, and 62 control subjects were included in the analysis. TNF2 allele frequency was significantly higher among control subjects than among all patients with leprosy or in the MB group (P<.05 and P<.01). For the IL-10 gene, the frequency of the homozygous -819TT genotype was significantly higher among patients than among control subjects. These data indicate that a relationship exists between TNF-alpha and IL-10 promoter polymorphisms and the development of PB leprosy.
- Published
- 2002
- Full Text
- View/download PDF
25. Chronic obstructive pulmonary disease is associated with the -1055 IL-13 promoter polymorphism.
- Author
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van der Pouw Kraan TC, Küçükaycan M, Bakker AM, Baggen JM, van der Zee JS, Dentener MA, Wouters EF, and Verweij CL
- Subjects
- Adult, Aged, Female, Humans, Immunoglobulin E blood, Male, Middle Aged, Polymorphism, Genetic, Genetic Predisposition to Disease, Interleukin-13 genetics, Promoter Regions, Genetic, Pulmonary Disease, Chronic Obstructive genetics
- Abstract
IL-13 is strongly implicated in the development of asthma and chronic obstructive pulmonary disease (COPD). We previously identified an IL-13 promoter polymorphism (-1055 C to T) that is associated with allergic asthma. We now report an increased frequency of the -1055 T allele in COPD patients compared to healthy controls (P=0.002) and compared to a second control group consisting of smoking individuals with normal lung function (P=0.01). A closely linked IL-13 exon polymorphism is present at normal allelic frequencies (P=0.3 and 0.4, respectively). In addition, we observed a normal distribution of two IL-4 polymorphisms at positions -590 and +33 (P=0.2 and 0.9, respectively). These results could implicate a functional role for the IL-13 promoter polymorphism in the enhanced risk to develop COPD.
- Published
- 2002
- Full Text
- View/download PDF
26. Relationship of polymorphisms of the Interleukin-1 gene cluster to occurrence and severity of rheumatoid arthritis.
- Author
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Kaijzel EL, van Dongen H, Bakker AM, Breedveld FC, Huizinga TW, and Verweij CL
- Subjects
- Alleles, Arthritis, Rheumatoid diagnosis, Arthritis, Rheumatoid epidemiology, Female, Humans, Interleukin-1 pharmacology, Molecular Sequence Data, Polymerase Chain Reaction, Sequence Analysis, DNA, Arthritis, Rheumatoid genetics, Interleukin-1 genetics, Multigene Family, Polymorphism, Genetic
- Abstract
Interleukin-1 (IL-1) has been implicated in the pathogenesis of rheumatoid arthritis (RA). We investigated whether IotaL-1 gene locus polymorphisms are associated with susceptibility to or severity of RA. Genotyping for IL-1alpha, IL-1beta and IL-1Ra single nucleotide polymorphisms (SNPs) performed in a cross-sectional group of 312 consecutive RA patients (RA-group 1) and a cohort of 94 incident female RA patients (RA-group 2) revealed that the rare IL-1RN + 2017 C allele was significantly increased in RA compared to controls (n = 245). A retrospective analysis in RA-group 1 showed no significant associations between IL-1 genotypes and disease severity. A prospective study in RA-group 2 demonstrated that the extent of joint destruction over 12 years was higher in patients genotyped heterozygous for the IL-1 A + 4845, IL-1B + 3953 and IL-1RN + 5111 SNPs compared to homozygous wildtype patients, although differences did not reach statistical significance. These data indicate that the IL-1RN + 2017 polymorphism is associated with susceptibility to RA.
- Published
- 2002
- Full Text
- View/download PDF
27. Polymorphisms in or near tumour necrosis factor (TNF)-gene do not determine levels of endotoxin-induced TNF production.
- Author
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de Jong BA, Westendorp RG, Bakker AM, and Huizinga TW
- Subjects
- Adult, Base Sequence, Female, HLA-DR Antigens genetics, Haplotypes, Heterozygote, Humans, Male, Microsatellite Repeats, Middle Aged, Netherlands, Polymorphism, Single Nucleotide, Endotoxins pharmacology, Polymorphism, Genetic, Tumor Necrosis Factor-alpha biosynthesis, Tumor Necrosis Factor-alpha genetics
- Abstract
Innate differences in tumour necrosis factor (TNF) production have been associated with susceptibility for and outcome of inflammatory diseases. Several studies have tried to identify whether polymorphisms in or near the TNF gene or other markers on the short arm of chromosome 6 (6p21) are related to differences in TNF production. Data on these associations are conflicting. Therefore, we conducted a study among 129 healthy individuals in which TNF production was determined upon stimulation with endotoxin in whole blood cultures. TNFa microsatellite, TNF single nucleotide polymorphisms at position +489, -238, -308 and -376 typing was performed. The data revealed that alleles of TNFa microsatellite and carriership of TNF polymorphisms were not related to TNF production. We conclude that the genes determing the differences in endotoxin-induced TNF production have not been yet identified.
- Published
- 2002
- Full Text
- View/download PDF
28. Conventional and controlled release valproate in children with epilepsy: a cross-over study comparing plasma levels and cognitive performances.
- Author
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Brouwer OF, Pieters MS, Edelbroek PM, Bakker AM, van Geel AA, Stijnen T, Jennekens-Schinkel A, Lanser JB, and Peters AC
- Subjects
- Adolescent, Attention drug effects, Child, Child, Preschool, Delayed-Action Preparations, Epilepsy blood, Epilepsy psychology, Female, Humans, Male, Neuropsychological Tests, Psychomotor Performance drug effects, Valproic Acid blood, Valproic Acid pharmacokinetics, Cognition drug effects, Epilepsy drug therapy, Valproic Acid therapeutic use
- Abstract
We studied plasma levels and behavioural effects of a newly developed controlled release formulation of valproate (VPA-CR) in children with epilepsy. Valproate plasma levels and performances in attention and vigilance tasks were monitored during a 12-h period (daytime), both during monotherapy of conventional valproate (VPA) and 4 weeks after switching to a similar dosage of VPA-CR taken once daily. There was no significant difference between the two formulations with respect to mean diurnal trough and peak valproate plasma levels, and to mean fluctuation. The significantly higher Cmax/Cmin ratio during VPA-CR seems mainly due to low valproate plasma levels early in the morning. Neuropsychological assessment showed no significant differences, either between patients and controls, or within patients and controls when comparing the results obtained on the VPA and VPA-CR day. During both VPA and VPA-CR treatment, no correlation was found between cognitive performance and valproate plasma levels. The advantage of VPA-CR is that the once daily regimen may increase compliance and is more convenient for schoolchildren.
- Published
- 1992
- Full Text
- View/download PDF
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