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Search Results: 1 - 10 of 738798 matches for " Joke J. F. A. van Vugt "
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Multiple Aspects of ATP-Dependent Nucleosome Translocation by RSC and Mi-2 Are Directed by the Underlying DNA Sequence
Joke J. F. A. van Vugt, Martijn de Jager, Magdalena Murawska, Alexander Brehm, John van Noort, Colin Logie
PLOS ONE , 2009, DOI: 10.1371/journal.pone.0006345
Abstract: Background Chromosome structure, DNA metabolic processes and cell type identity can all be affected by changing the positions of nucleosomes along chromosomal DNA, a reaction that is catalysed by SNF2-type ATP-driven chromatin remodelers. Recently it was suggested that in vivo, more than 50% of the nucleosome positions can be predicted simply by DNA sequence, especially within promoter regions. This seemingly contrasts with remodeler induced nucleosome mobility. The ability of remodeling enzymes to mobilise nucleosomes over short DNA distances is well documented. However, the nucleosome translocation processivity along DNA remains elusive. Furthermore, it is unknown what determines the initial direction of movement and how new nucleosome positions are adopted. Methodology/Principal Findings We have used AFM imaging and high resolution PAGE of mononucleosomes on 600 and 2500 bp DNA molecules to analyze ATP-dependent nucleosome repositioning by native and recombinant SNF2-type enzymes. We report that the underlying DNA sequence can control the initial direction of translocation, translocation distance, as well as the new positions adopted by nucleosomes upon enzymatic mobilization. Within a strong nucleosomal positioning sequence both recombinant Drosophila Mi-2 (CHD-type) and native RSC from yeast (SWI/SNF-type) repositioned the nucleosome at 10 bp intervals, which are intrinsic to the positioning sequence. Furthermore, RSC-catalyzed nucleosome translocation was noticeably more efficient when beyond the influence of this sequence. Interestingly, under limiting ATP conditions RSC preferred to position the nucleosome with 20 bp intervals within the positioning sequence, suggesting that native RSC preferentially translocates nucleosomes with 15 to 25 bp DNA steps. Conclusions/Significance Nucleosome repositioning thus appears to be influenced by both remodeler intrinsic and DNA sequence specific properties that interplay to define ATPase-catalyzed repositioning. Here we propose a successive three-step framework consisting of initiation, translocation and release steps to describe SNF2-type enzyme mediated nucleosome translocation along DNA. This conceptual framework helps resolve the apparent paradox between the high abundance of ATP-dependent remodelers per nucleus and the relative success of sequence-based predictions of nucleosome positioning in vivo.
K. Steenbrink, Catholics in Indonesia 1808-1942. A documented history, I, A modest recovery 1808-1903
J.P.A. van Vugt
BMGN : Low Countries Historical Review , 2005,
Abstract:
Women’s Attitudes towards the Option to Choose between Karyotyping and Rapid Targeted Testing during Pregnancy
Angelique J. A. Kooper,Dominique F. C. M. Smeets,Ilse Feenstra,Lia D. E. Wijnberger,Robbert J. P. Rijnders,Rik W. P. Quartero,Peter F. Boekkooi,John M. G. van Vugt,Arie P. T. Smits
Obstetrics and Gynecology International , 2013, DOI: 10.1155/2013/636459
Abstract: Objectives. Pregnant women, referred because of an increased risk of fetal Down syndrome, who underwent an invasive prenatal procedure were offered a choice between karyotyping and rapid targeted testing. This study aims to assess women’s attitudes and experiences towards what option to choose. Methods. A retrospective multicentre survey (2008–2010) was conducted among 1370 women. General questions were asked about decision making issues, followed by personal questions about their experiences in choice making, test preference, influence of others, and possible regrets. Results. In total, 90.1% of the respondents ( ) indicated that pregnant women are able to choose, although 33.1% stated that the choice can best be made by a professional. 18.4% indicated that making a choice places a burden on women. In 96.4%, respondents preferred to have the option to choose again in case of a next pregnancy, whereas 2.7% preferred the choice to be made by a professional. Regret was indicated by 1.2%. Decision making was influenced by others in 64.9%. A slightly higher preference for karyotyping was indicated by 52.7% of the respondents. Conclusions. Positive attitudes and experiences were expressed towards the option to choose. Respondents took decisions freely, although sometimes influenced by a partner or a professional, to follow their individual perspectives. 1. Introduction Currently, in many prenatal centres, rapid targeted tests (QF-PCR: quantitative fluorescent polymerase chain reaction or MLPA: multiplex ligation-dependent probe amplification) are used for the prenatal detection of common chromosomal aneuploidies. The need for rapid testing methods, not requiring cell culture, has been recognized in order to improve pregnancy management and to alleviate parental anxiety [1, 2]. Analysis of large series of prenatal samples by QF-PCR or MLPA has shown that both tests, deliberately targeted to the analysis of selected chromosomes, that is, chromosomes 13, 18, and 21 with or without inclusion of the sex chromosomes, allow the detection of the vast majority of chromosome abnormalities in prenatal samples [3–9]. The application of such targeted tests as stand-alone tests is still strongly debated in various countries, and therefore, different approaches are presently applied. In some centers, women with a risk of having a fetus with a chromosomal abnormality (without fetal ultrasound anomalies) will only be offered a rapid targeted test, whereas in other centres, they can choose between a rapid targeted test and karyotyping or, alternatively, are offered routine
Lung function decline in relation to diagnostic criteria for airflow obstruction in respiratory symptomatic subjects
Reinier P Akkermans, Marvin A Berrevoets, Ivo J Smeele, Annelies E Lucas, Bart P Thoonen, Joke G Grootens-Stekelenburg, Yvonne F Heijdra, Chris van Weel, Tjard R Schermer
BMC Pulmonary Medicine , 2012, DOI: 10.1186/1471-2466-12-12
Abstract: We studied 3,324 respiratory symptomatic subjects referred to primary care diagnostic centres for spirometry. The cohort was subdivided into four categories based on presence or absence of obstruction according to the fixed and LLN FEV1/FVC cutpoints. Postbronchodilator FEV1 decline served as primary outcome to compare subjects between the respective categories.918 subjects were obstructive according to the fixed FEV1/FVC cutpoint; 389 (42%) of them were non-obstructive according to the LLN cutpoint. In smokers, postbronchodilator FEV1 decline was 21 (SE 3) ml/year in those non-obstructive according to both cutpoints, 21 (7) ml/year in those obstructive according to the fixed but not according to the LLN cutpoint, and 50 (5) ml/year in those obstructive according to both cutpoints (p = 0.004).This study showed that respiratory symptomatic 40+ smokers and non-smokers who show FEV1/FVC values below the fixed 0.70 cutpoint but above their age/gender specific LLN value did not show accelerated FEV1 decline, in contrast with those showing FEV1/FVC values below their LLN cutpoint.Chronic obstructive pulmonary disease (COPD) is a disease that is characterized by irreversible and progressive airflow obstruction, and is associated with high morbidity and mortality [1]. COPD is predominantly diagnosed in adults aged well over 40 years. In developed countries cigarette smoking is the main risk factor [2], and accelerated lung function decline is the predominant clinical and prognostic hallmark of the disease [3]. Spirometry is recommended to assess airflow obstruction, i.e. to establish the ratio of the forced expiratory volume in one second (FEV1) and forced vital capacity (FVC). Next, severity of obstruction is quantified by calculation of FEV1 as percentage of predicted value.For subjects suspected of having the disease current clinical COPD guidelines recommend a fixed FEV1/FVC cutpoint < 0.70 (after administration of a bronchodilator) to decide whether or not airflow obst
Why Do Parents Prefer to Know the Fetal Sex as Part of Invasive Prenatal Testing?
Angelique J. A. Kooper,Jacqueline J. P. M. Pieters,Alex J. Eggink,Ton B. Feuth,Ilse Feenstra,Lia D. E. Wijnberger,Robbert J. P. Rijnders,Rik W. P. Quartero,Peter F. Boekkooi,John M. G. van Vugt,Arie P. T. Smits
ISRN Obstetrics and Gynecology , 2012, DOI: 10.5402/2012/524537
Abstract: Objectives. The aim of this study was to determine whether prospective parents, primarily referred for prenatal diagnosis to exclude Down syndrome, prefer to know the fetal sex as part of invasive testing. Methods. In this prospective study 400 pregnant women undergoing amniocentesis were invited to answer a questionnaire, including information about demographic factors, current pregnancy, and previous children. In two open-ended questions they were asked why they wanted to know the fetal sex after amniocentesis or ultrasound investigation. Scores were given for reasons that could have played a role in the wish whether or not to know the sex of their unborn child. Results. A total of 210 (52.5%) questionnaires were completed. Overall, 69.0% was interested to know the fetal sex as part of the diagnostic test result. The most important reasons were curiosity (77.8%), “just want to know” (68.0%), and “because it is possible” (66.8%). The overall knowledge of sex chromosomal disorders appeared low and did not seem to affect the parent’s wish to know the fetal sex. Almost all women (96.6%) planned to have a 20-week ultrasound scan and 96.2% thought the scan to be reliable in detecting the fetal sex. A minority (28%) was willing to learn the fetal sex by ultrasound examination, whereas 65% preferred to learn the fetal sex only after the amniocentesis. Conclusion. Personal values affect the parental desire to know or not to know the fetal sex. This does not appear to be affected by invasive prenatal testing and/or genetic knowledge of sex chromosomal disorders. 1. Background For prospective parents the option of knowing the fetal sex forms an important aspect during pregnancy. Sometimes early determination of fetal sex is clinically indicated, for example, for women who are carrier of an X-linked genetic condition and for who male foetuses are primarily at risk. In these cases the fetal sex is determined in free fetal DNA isolated from maternal plasma early during gestation (8 weeks; [1–3]). For most other couples, however, knowing the fetal sex before birth is only possible after ultrasound examination or prenatal invasive testing by chorionic villi sampling or amniocentesis. In most prenatal centres, parents are asked whether they want to have the sex of the fetus reported before they undergo an invasive procedure using traditional karyotyping or rapid aneuploidy testing. With traditional karyotyping it is obvious that sex chromosomes are an integral part of the test result. Sex chromosomal disorders such as Turner- (45,X), Klinefelter- (47,XXY), Triple X-
Polo-Like Kinase-1 Controls Aurora A Destruction by Activating APC/C-Cdh1
Renske van Leuken, Linda Clijsters, Wouter van Zon, Dan Lim, XueBiao Yao, Rob M. F. Wolthuis, Michael B. Yaffe, René H. Medema, Marcel A. T. M. van Vugt
PLOS ONE , 2009, DOI: 10.1371/journal.pone.0005282
Abstract: Polo-like kinase-1 (Plk1) is activated before mitosis by Aurora A and its cofactor Bora. In mitosis, Bora is degraded in a manner dependent on Plk1 kinase activity and the E3 ubiquitin ligase SCF-βTrCP. Here, we show that Plk1 is also required for the timely destruction of its activator Aurora A in late anaphase. It has been shown that Aurora A destruction is controlled by the auxiliary subunit Cdh1 of the Anaphase-Promoting Complex/Cyclosome (APC/C). Remarkably, we found that Plk1-depletion prevented the efficient dephosphorylation of Cdh1 during mitotic exit. Plk1 mediated its effect on Cdh1, at least in part, through direct phosphorylation of the human phosphatase Cdc14A, controlling the phosphorylation state of Cdh1. We conclude that Plk1 facilitates efficient Aurora A degradation through APC/C-Cdh1 activation after mitosis, with a potential role for hCdc14A.
Dynamics of Parasite Clearance in Cutaneous Leishmaniasis Patients Treated with Miltefosine
Thomas P. C. Dorlo ,Pieter P. A. M. van Thiel,Gerard J. Schoone,Ymkje Stienstra,Michèle van Vugt,Jos H. Beijnen,Peter J. de Vries
PLOS Neglected Tropical Diseases , 2011, DOI: 10.1371/journal.pntd.0001436
Abstract: Parasite loads were quantified in repeated skin biopsies from lesions of 2 patients with Old-World cutaneous leishmaniasis (CL) caused by Leishmania major and L. infantum during and after treatment with miltefosine. Miltefosine induced a rapid therapeutic effect on both infections with an initial decline of parasites of ~1 log/week for the L. major infection. These observations illustrate the usability of quantifying parasite loads in skin lesions as a pharmacodynamic measure and quantitative descriptor of drug effect for CL supporting clinical assessment.
The Melanin-Concentrating Hormone (MCH) System Modulates Behaviors Associated with Psychiatric Disorders
Shinjae Chung, Michel M. M. Verheij, Peter Hesseling, Ruben W. M. van Vugt, Mahalah Buell, James D. Belluzzi, Mark A. Geyer, Gerard J. M. Martens, Olivier Civelli
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0019286
Abstract: Deficits in sensorimotor gating measured by prepulse inhibition (PPI) of the startle have been known as characteristics of patients with schizophrenia and related neuropsychiatric disorders. PPI disruption is thought to rely on the activity of the mesocorticolimbic dopaminergic system and is inhibited by most antipsychotic drugs. These drugs however act also at the nigrostriatal dopaminergic pathway and exert adverse locomotor responses. Finding a way to inhibit the mesocorticolimbic- without affecting the nigrostriatal-dopaminergic pathway may thus be beneficial to antipsychotic therapies. The melanin-concentrating hormone (MCH) system has been shown to modulate dopamine-related responses. Its receptor (MCH1R) is expressed at high levels in the mesocorticolimbic and not in the nigrostriatal dopaminergic pathways. Interestingly a genomic linkage study revealed significant associations between schizophrenia and markers located in the MCH1R gene locus. We hypothesize that the MCH system can selectively modulate the behavior associated with the mesocorticolimbic dopamine pathway. Using mice, we found that central administration of MCH potentiates apomorphine-induced PPI deficits. Using congenic rat lines that differ in their responses to PPI, we found that the rats that are susceptible to apomorphine (APO-SUS rats) and exhibit PPI deficits display higher MCH mRNA expression in the lateral hypothalamic region and that blocking the MCH system reverses their PPI deficits. On the other hand, in mice and rats, activation or inactivation of the MCH system does not affect stereotyped behaviors, dopamine-related responses that depend on the activity of the nigrostriatal pathway. Furthermore MCH does not affect dizocilpine-induced PPI deficit, a glutamate related response. Thus, our data present the MCH system as a regulator of sensorimotor gating, and provide a new rationale to understand the etiologies of schizophrenia and related psychiatric disorders.
Species-Directed Therapy for Leishmaniasis in Returning Travellers: A Comprehensive Guide
Caspar J. Hodiamont ,Piet A. Kager,Aldert Bart,Henry J. C. de Vries,Pieter P. A. M. van Thiel,Tjalling Leenstra,Peter J. de Vries,Michèle van Vugt,Martin P. Grobusch,Tom van Gool
PLOS Neglected Tropical Diseases , 2014, DOI: 10.1371/journal.pntd.0002832
Abstract: Background Leishmaniasis is increasingly reported among travellers. Leishmania species vary in sensitivity to available therapies. Fast and reliable molecular techniques have made species-directed treatment feasible. Many treatment trials have been designed poorly, thus developing evidence-based guidelines for species-directed treatment is difficult. Published guidelines on leishmaniasis in travellers do not aim to be comprehensive or do not quantify overall treatment success for available therapies. We aimed at providing comprehensive species-directed treatment guidelines. Methodology/Principal Findings English literature was searched using PubMed. Trials and observational studies were included if all cases were parasitologically confirmed, the Leishmania species was known, clear clinical end-points and time points for evaluation of treatment success were defined, duration of follow-up was adequate and loss to follow-up was acceptable. The proportion of successful treatment responses was pooled using mixed effects methods to estimate the efficacy of specific therapies. Final ranking of treatment options was done by an expert panel based on pooled efficacy estimates and practical considerations. 168 studies were included, with 287 treatment arms. Based on Leishmania species, symptoms and geography, 25 clinical categories were defined and therapy options ranked. In 12/25 categories, proposed treatment agreed with highest efficacy data from literature. For 5/25 categories no literature was found, and in 8/25 categories treatment advise differed from literature evidence. For uncomplicated cutaneous leishmaniasis, combination of intralesional antimony with cryotherapy is advised, except for L. guyanensis and L. braziliensis infections, for which systemic treatment is preferred. Treatment of complicated (muco)cutaneous leishmaniasis differs per species. For visceral leishmaniasis, liposomal amphotericin B is treatment of choice. Conclusions/Significance Our study highlights current knowledge about species-directed therapy of leishmaniasis in returning travellers and also demonstrates lack of evidence for treatment of several clinical categories. New data can easily be incorporated in the presented overview. Updates will be of use for clinical decision making and for defining further research.
Cardiac Responses during Picture Viewing in Young Male Patients with Schizophrenia
Roelie J. Hempel,Julian F. Thayer,Christian H. R?der,Hugo G. van Steenis,Nico J. M. van Beveren,Joke H. M. Tulen
Cardiovascular Psychiatry and Neurology , 2012, DOI: 10.1155/2012/858562
Abstract: Previous research investigating the emotion recognition ability in patients with schizophrenia has mainly focused on the recognition of facial expressions. To broaden our understanding of emotional processes in patients with schizophrenia, this study aimed to investigate whether these patients experience and process other emotionally evocative stimuli differently from healthy participants. To investigate this, we measured the cardiac and subjective responses of 33 male patients (9 with and 24 without antipsychotic medication) and 40 male control subjects to emotion-eliciting pictures. Cardiac responses were chosen as an outcome measure because previous research has indicated that these are linked with attentional and emotional processes and provide a more objective measure than self-report measures alone. The differences in cardiac responses between patients and controls were limited to medicated patients: only the medicated patients showed significantly decreased cardiac orienting responses compared with control subjects, regardless of picture contents. These results indicate that medicated patients directed less attention towards emotion-eliciting pictures than controls. Decreased attentional resources while processing emotional evocative stimuli could lead to incorrect appraisals of the environment and may have detrimental emotional and social consequences, contributing to chronic stress levels and an increased risk for cardiovascular disease. 1. Introduction An extensive amount of research papers has been published on the impaired emotional functioning of patients with schizophrenia. Most of this research has focused on the impaired ability of these patients to recognize emotions from facial expressions [1], which is crucial for forming and maintaining interpersonal relationships [2, 3], and patients with schizophrenia are known to experience difficulties with social functioning [4, 5]. Although schizophrenic patients seem impaired in their ability to recognize and express emotional facial expressions, they do appear to experience emotions in a way similar to healthy controls. Several studies have found that patients and controls did not differ in their subjective ratings of pleasantness and arousal when presented with emotion-eliciting pictures [6–9]. In two other studies, schizophrenic patients reported that they experienced the same amount of pleasant emotions as healthy controls, but greater amounts of unpleasant emotions in response to emotion-eliciting stimuli [10, 11]. It has also been found that schizophrenic patients experience less
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