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Search Results: 1 - 10 of 200591 matches for " Jacomijn P Dijksterhuis "
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Heterotrimeric G protein-dependent WNT-5A signaling to ERK1/2 mediates distinct aspects of microglia proinflammatory transformation
Carina Halleskog, Jacomijn P Dijksterhuis, Michaela BC Kilander, Javier Becerril-Ortega, Carlos J Villaescusa, Eva Lindgren, Ernest Arenas, Gunnar Schulte
Journal of Neuroinflammation , 2012, DOI: 10.1186/1742-2094-9-111
Abstract: Mouse brain sections were used for immunohistochemistry. Primary isolated microglia and astrocytes were employed to characterize the WNT-induced inflammatory transformation and underlying intracellular signaling pathways by immunoblotting, quantitative mRNA analysis, proliferation and invasion assays. Further, measurements of G protein activation by [γ-35?S]GTP binding, examination of calcium fluxes and cyclic AMP production were used to define intracellular signaling pathways.Astrocytes in the adult mouse brain express high levels of WNT-5A, which could serve as a novel astroglia-microglia communication pathway. The WNT-5A-induced proinflammatory microglia response is characterized by increased expression of inducible nitric oxide synthase, cyclooxygenase-2, cytokines, chemokines, enhanced invasive capacity and proliferation. Mapping of intracellular transduction pathways reveals that WNT-5A activates heterotrimeric Gi/o proteins to reduce cyclic AMP levels and to activate a Gi/o protein/phospholipase C/calcium-dependent protein kinase/extracellular signal-regulated kinase 1/2 (ERK1/2) axis. We show further that WNT-5A-induced ERK1/2 signaling is responsible for distinct aspects of the proinflammatory transformation, such as matrix metalloprotease 9/13 expression, invasion and proliferation.Thus, WNT-5A-induced and G protein-dependent signaling to ERK1/2 is important for the regulation of proinflammatory responses in mouse primary microglia cells. We show for the first time that WNT-5A/G protein signaling mediates physiologically important processes in primary mammalian cells with natural receptor and G protein stochiometry. Consequently, WNT-5A emerges as an important means of astrocyte-microglia communication and we, therefore, suggest WNT-5A as a new player in neuroinflammatory conditions, such as neurodegenerative disease, hypoxia, stroke, injury and infection.
The rich get richer and the poor get poorer
Ingmar H. A. Franken,Irina Georgieva,Peter Muris,Ap Dijksterhuis
Judgment and Decision Making , 2006,
Abstract: Some studies have found that choices become more risk averse after gains and more risk seeking after losses, although other studies have found the opposite. The latter tend to use hypothetical cases that encourage deliberation. In the current study, we examined the effects of prior gains and losses on a task designed to encourage less reflective decision making, the Iowa Gambling Task (IGT). Fifty participants conducted a manipulated decision-making task in which one group gained money, whereas the other group lost money, followed by the IGT. Participants who experienced a prior monetary loss displayed more risky choice behavior on the IGT than subjects who experienced a prior gain. These effects were not mediated by a positive or negative affect, although the sample size may have been too small to detect a small effect.
Biodiversity in the Cladosporium herbarum complex (Davidiellaceae, Capnodiales), with standardisation of methods for Cladosporium taxonomy and diagnostics
K. Schubert,J.Z. Groenewald,U. Braun,J. Dijksterhuis
Studies in Mycology , 2007,
Abstract: The Cladosporium herbarum complex comprises five species for which Davidiella teleomorphs are known. Cladosporium herbarum s. str. (D. tassiana), C. macrocarpum (D. macrocarpa) and C. bruhnei (D. allicina) are distinguishable by having conidia of different width, and by teleomorph characters. Davidiella variabile is introduced as teleomorph of C. variabile, a homothallic species occurring on Spinacia, and D. macrospora is known to be the teleomorph of C. iridis on Iris spp. The C. herbarum complex combines low molecular distance with a high degree of clonal or inbreeding diversity. Entities differ from each other by multilocus sequence data and by phenetic differences, and thus can be interpreted to represent individual taxa. Isolates of the C. herbarum complex that were formerly associated with opportunistic human infections, cluster with C. bruhnei. Several species are newly described from hypersaline water, namely C. ramotenellum, C. tenellum, C. subinflatum, and C. herbaroides. Cladosporium pseudiridis collected from Iris sp. in New Zealand, is also a member of this species complex and shown to be distinct from C. iridis that occurs on this host elsewhere in the world. A further new species from New Zealand is C. sinuosum on Fuchsia excorticata. Cladosporium antarcticum is newly described from a lichen, Caloplaca regalis, collected in Antarctica, and C. subtilissimum from grape berries in the U.S.A., while the new combination C. ossifragi, the oldest valid name of the Cladosporium known from Narthecium in Europe, is proposed. Standard protocols and media are herewith proposed to facilitate future morphological examination of Cladosporium spp. in culture, and neotypes or epitypes are proposed for all species treated.
Classifying visuomotor workload in a driving simulator using subject specific spatial brain patterns
Chris Dijksterhuis,Dick de Waard,Ben L. J. M. Mulder
Frontiers in Neuroscience , 2013, DOI: 10.3389/fnins.2013.00149
Abstract: A passive Brain Computer Interface (BCI) is a system that responds to the spontaneously produced brain activity of its user and could be used to develop interactive task support. A human-machine system that could benefit from brain-based task support is the driver-car interaction system. To investigate the feasibility of such a system to detect changes in visuomotor workload, 34 drivers were exposed to several levels of driving demand in a driving simulator. Driving demand was manipulated by varying driving speed and by asking the drivers to comply to individually set lane keeping performance targets. Differences in the individual driver's workload levels were classified by applying the Common Spatial Pattern (CSP) and Fisher's linear discriminant analysis to frequency filtered electroencephalogram (EEG) data during an off line classification study. Several frequency ranges, EEG cap configurations, and condition pairs were explored. It was found that classifications were most accurate when based on high frequencies, larger electrode sets, and the frontal electrodes. Depending on these factors, classification accuracies across participants reached about 95% on average. The association between high accuracies and high frequencies suggests that part of the underlying information did not originate directly from neuronal activity. Nonetheless, average classification accuracies up to 75–80% were obtained from the lower EEG ranges that are likely to reflect neuronal activity. For a system designer, this implies that a passive BCI system may use several frequency ranges for workload classifications.
Species and ecological diversity within the Cladosporium cladosporioides complex (Davidiellaceae, Capnodiales)
K. Bensch,J.Z. Groenewald,J. Dijksterhuis,M. Starink-Willemse
Studies in Mycology , 2010,
Abstract: The genus Cladosporium is one of the largest genera of dematiaceous hyphomycetes, and is characterised by a coronate scar structure, conidia in acropetal chains and Davidiella teleomorphs. Based on morphology and DNA phylogeny, the species complexes of C. herbarum and C. sphaerospermum have been resolved, resulting in the elucidation of numerous new taxa. In the present study, more than 200 isolates belonging to the C. cladosporioides complex were examined and phylogenetically analysed on the basis of DNA sequences of the nuclear ribosomal RNA gene operon, including the internal transcribed spacer regions ITS1 and ITS2, the 5.8S nrDNA, as well as partial actin and translation elongation factor 1-α gene sequences. For the saprobic, widely distributed species Cladosporium cladosporioides, both a neotype and epitype are designated in order to specify a well established circumscription and concept of this species. Cladosporium tenuissimum and C. oxysporum, two saprobes abundant in the tropics, are epitypified and shown to be allied to, but distinct from C. cladosporioides. Twenty-two species are newly described on the basis of phylogenetic characters and cryptic morphological differences. The most important phenotypic characters for distinguishing species within the C. cladosporioides complex, which represents a monophyletic subclade within the genus, are shape, width, length, septation and surface ornamentation of conidia and conidiophores; length and branching patterns of conidial chains and hyphal shape, width and arrangement. Many of the treated species, e.g., C. acalyphae, C. angustisporum, C. australiense, C. basiinflatum, C. chalastosporoides, C. colocasiae, C. cucumerinum, C. exasperatum, C. exile, C. flabelliforme, C. gamsianum, and C. globisporum are currently known only from specific hosts, or have a restricted geographical distribution. A key to all species recognised within the C. cladosporioides complex is provided
Expression of the insulin-like growth factor (IGF) system and steroidogenic enzymes in canine testis tumors
Monique AJ Peters, Jan A Mol, Monique E van Wolferen, Marja A Oosterlaken-Dijksterhuis, Katja J Teerds, Frederik J van Sluijs
Reproductive Biology and Endocrinology , 2003, DOI: 10.1186/1477-7827-1-22
Abstract: The prevalence of testicular tumors is higher in dogs than in any other species of domestic animals and higher than in humans. Especially in older dogs the prevalence can be as high as 60% [1]. Testis tumors in dogs seldom metastasize and can be considered to be benign proliferations [2]. The three main types of testis tumors in dogs are Sertoli cell tumors, seminomas, and Leydig cell tumors and combinations of them occur often. These tumors are seldom lethal, but can cause feminization of the dog, which in severe cases can lead to a fatal bone marrow depression [2]. Feminization is caused by hyperestrogenism and is mostly associated with Sertoli cell tumors but Leydig cell tumors and seminomas have also been associated with this syndrome. When feminization occurs in dogs with a seminoma, it is presumed that a co-existing Sertoli or Leydig cell tumor is responsible for the hyperestrogenism [2].There is evidence that growth factors of the insulin-like growth factor regulatory system, such as insulin-like growth factor-I (IGF-I) and IGF-II, are involved in the pathobiology of neoplasia, both in terms of the risk of developing a tumor and in terms of its behavior [3].Insulin-like growth factor-I (IGF-I) and IGF-II are peptides believed to play an important role in the regulation of cellular growth and differentiation. The IGFs are synthesized and secreted by many tissues. They can act as endocrine hormones that are being transported by the circulation to distant sites of action, but they can also act locally by paracrine or autocrine mechanisms. The biological activity of IGF-I and IGF-II is modulated by their binding proteins and receptors. Two distinct receptors and six different high-affinity binding proteins have been identified [4,5].Both IGF-I and IGF-II are produced locally in the testis [6-9]. The IGF system plays an important role in the local regulation of testicular function [10]. IGF-1 has different roles in the two major compartments of the testis, the int
Chronic Allopurinol Treatment during the Last Trimester of Pregnancy in Sows: Effects on Low and Normal Birth Weight Offspring
Elise T. Gieling, Alexandra Antonides, Johanna Fink-Gremmels, Kim ter Haar, Wikke I. Kuller, Ellen Meijer, Rebecca E. Nordquist, Jacomijn M. Stouten, Elly Zeinstra, Franz Josef van der Staay
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0086396
Abstract: Low-birth-weight (LBW) children are born with several risk factors for disease, morbidity and neonatal mortality, even if carried to term. Placental insufficiency leading to hypoxemia and reduced nutritional supply is the main cause for LBW. Brain damage and poor neurological outcome can be the consequence. LBW after being carried to term gives better chances for survival, but these children are still at risk for poor health and the development of cognitive impairments. Preventive therapies are not yet available. We studied the risk/efficacy of chronic prenatal treatment with the anti-oxidative drug allopurinol, as putative preventive treatment in piglets. LBW piglets served as a natural model for LBW. A cognitive holeboard test was applied to study the learning and memory abilities of these allopurinol treated piglets after weaning. Preliminary analysis of the plasma concentrations in sows and their piglets suggested that a daily dose of 15 mg.kg?1 resulted in effective plasma concentration of allopurinol in piglets. No adverse effects of chronic allopurinol treatment were found on farrowing, birth weight, open field behavior, learning abilities, relative brain, hippocampus and spleen weights. LBW piglets showed increased anxiety levels in an open field test, but cognitive performance was not affected by allopurinol treatment. LBW animals treated with allopurinol showed the largest postnatal compensatory body weight gain. In contrast to a previous study, no differences in learning abilities were found between LBW and normal-birth-weight piglets. This discrepancy might be attributable to experimental differences. Our results indicate that chronic prenatal allopurinol treatment during the third trimester of pregnancy is safe, as no adverse side effects were observed. Compensatory weight gain of treated piglets is a positive indication for the chronic prenatal use of allopurinol in these animals. Further studies are needed to assess the possible preventive effects of allopurinol on brain functions in LBW piglets.
Hybrid Fuzzy Controller Based Frequency Regulation in Restructured Power System  [PDF]
P. Anitha, P. Subburaj
Circuits and Systems (CS) , 2016, DOI: 10.4236/cs.2016.76065
Abstract: This paper discusses the implementation of Load Frequency Control (LFC) in restructured power system using Hybrid Fuzzy controller. The formulation of LFC in open energy market is much more challenging; hence it needs an intelligent controller to adapt the changes imposed by the dynamics of restructured bilateral contracts. Fuzzy Logic Control deals well with uncertainty and indistinctness while Particle Swarm Optimization (PSO) is a well-known optimization tool. Abovementioned techniques are combined and called as Hybrid Fuzzy to improve the dynamic performance of the system. Frequency control of restructured system has been achieved by automatic Membership Function (MF) tuned fuzzy logic controller. The parameters defining membership function has been tuned and updated from time to time using Particle Swarm Optimization (PSO). The robustness of the proposed hybrid fuzzy controller has been compared with conventional fuzzy logic controller using performance measures like overshoot and settling time following a step load perturbation. The motivation for using membership function tuning using PSO is to show the behavior of the controller for a wide range of system parameters and load changes. Error based analysis with parametric uncertainties and load changes is tested on a two-area restructured power system.
Integral Performance Criteria Based Analysis of Load Frequency Control in Bilateral Based Market  [PDF]
P. Anitha, P. Subburaj
Circuits and Systems (CS) , 2016, DOI: 10.4236/cs.2016.76086
Abstract: Performance index based analysis is made to examine and highlight the effective application of Particle Swarm Optimization (PSO) to optimize the Proportional Integral gains for Load Frequency Control (LFC) in a restructured power system that operates under Bilateral based policy scheme. Various Integral Performance Criteria measures are taken as fitness function in PSO and are compared using overshoot, settling time and frequency and tie-line power deviation following a step load perturbation (SLP). The motivation for using different fitness technique in PSO is to show the behavior of the controller for a wide range of system parameters and load changes. Error based analysis with parametric uncertainties and load changes are tested on a two-area restructured power system. The results of the proposed PSO based controller show the better performance compared to the classical Ziegler-Nichols (Z-N) tuned PI andFuzzy Rule based PI controller.
Projection of the Semi-Axes of the Ellipse of Intersection  [PDF]
P. P. Klein
Applied Mathematics (AM) , 2017, DOI: 10.4236/am.2017.89097
Abstract:
It is well known that the line of intersection of an ellipsoid and a plane is an ellipse (see for instance [1]). In this note the semi-axes of the ellipse of intersection will be projected from 3d space onto a 2d plane. It is shown that the projected semi-axes agree with results of a method used by Bektas [2] and also with results obtained by Schrantz [3].
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