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Search Results: 1 - 10 of 34601 matches for " Dani?lle van Versendaal "
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The Role of GABAergic Inhibition in Ocular Dominance Plasticity
J. Alexander Heimel,Danille van Versendaal,Christiaan N. Levelt
Neural Plasticity , 2011, DOI: 10.1155/2011/391763
Abstract: During the last decade, we have gained much insight into the mechanisms that open and close a sensitive period of plasticity in the visual cortex. This brings the hope that novel treatments can be developed for brain injuries requiring renewed plasticity potential and neurodevelopmental brain disorders caused by defective synaptic plasticity. One of the central mechanisms responsible for opening the sensitive period is the maturation of inhibitory innervation. Many molecular and cellular events have been identified that drive this developmental process, including signaling through BDNF and IGF-1, transcriptional control by OTX2, maturation of the extracellular matrix, and GABA-regulated inhibitory synapse formation. The mechanisms through which the development of inhibitory innervation triggers and potentially closes the sensitive period may involve plasticity of inhibitory inputs or permissive regulation of excitatory synapse plasticity. Here, we discuss the current state of knowledge in the field and open questions to be addressed. 1. Sensitive Periods of Plasticity Many things can be learned more easily during childhood than in adulthood, including speaking a new language, playing an instrument, or performing a sport. This is the consequence of how our brain develops. It seems to make sense to learn these skills in a rather permanent way when we are young so that we can take advantage of them when we are adults. This is not only true for learning skills or facts but reflects a general property of brain development where periods of enhanced experience-dependent plasticity in different cortical and subcortical brain regions are essential for achieving functional and reliable connectivity between brain areas. During the last decade, it has become clear that specific molecular and cellular mechanisms are in place that regulate the onset and offset of these sensitive periods [1], indicating that they are not simply the consequence of the brain regions involved becoming optimized but actively regulated periods of enhanced plasticity. Sensitive periods are not only essential for normal brain development, they are also protective in cases of brain damage during childhood. In the young brain, cortical areas are not yet fully committed to specific tasks and damage can still be compensated for by other brain areas taking over the lost functionality [2]. But sensitive periods can also cause important problems. If plasticity does not occur in a proper fashion during these periods, lifelong problems may occur. This can occur if the provided inputs are inadequate.
Perception of health risks of electromagnetic fields by MRI radiographers and airport security officers compared to the general Dutch working population: a cross sectional analysis
Diana van Dongen, Tjabe Smid, Danille RM Timmermans
Environmental Health , 2011, DOI: 10.1186/1476-069x-10-95
Abstract: Three occupational groups, the general Dutch working population (n = 567), airport security officers who work with metal detectors (n = 106), and MRI radiographers who work with MRI (n = 193), were compared on perceived risk of and positive and negative feelings towards EMF in general and of different EMF sources, and health concerns by using analyses of variances. Data were collected via an internet survey.Overall, MRI radiographers had a lower perceived risk, felt less negative, and more positive towards EMF and different sources of EMF than the general working population and the security officers. For security officers, feeling more positive about EMF was not significantly related to perceived risk of EMF in general or EMF of domestic sources. Feeling positive about a source did not generalize to a lower perceived risk, while negative feelings were stronger related to perceived risk. MRI radiographers had fewer health concerns regarding EMF than the other two groups, although they considered it more likely that EMF could cause physical complaints.These data show that although differences in occupation appear to be reflected in different perceptions of EMF, the level of occupational exposure to EMF as such does not predict the perceived health risk of EMF.In Europe, a debate is ongoing on exposure limits to protect workers from exposure to electromagnetic fields (EMF) [1]. The European Parliament and Council aimed to adopt a Directive which would protect workers who are exposed in the course of their work from known short-term adverse health effects [2]. Magnetic Resonance Imaging (MRI) researchers and many patients groups protested against the Directive and were given a four year reprieve to find a solution, while this would have serious consequences for clinical and research uses of MRI equipment, a device of which exposure would exceed the proposed exposure limits. Little is known about how MRI radiographers perceive possible health risk of EMF, or other worker
Genome-wide association studies on HIV susceptibility, pathogenesis and pharmacogenomics
van Manen Danille,van ‘t Wout Angélique B,Schuitemaker Hanneke
Retrovirology , 2012, DOI: 10.1186/1742-4690-9-70
Abstract: Susceptibility to HIV-1 and the clinical course after infection show a substantial heterogeneity between individuals. Part of this variability can be attributed to host genetic variation. Initial candidate gene studies have revealed interesting host factors that influence HIV infection, replication and pathogenesis. Recently, genome-wide association studies (GWAS) were utilized for unbiased searches at a genome-wide level to discover novel genetic factors and pathways involved in HIV-1 infection. This review gives an overview of findings from the GWAS performed on HIV infection, within different cohorts, with variable patient and phenotype selection. Furthermore, novel techniques and strategies in research that might contribute to the complete understanding of virus-host interactions and its role on the pathogenesis of HIV infection are discussed.
Conducting research in individual patients: lessons learnt from two series of N-of-1 trials
Anke CM Wegman, Danille AWM van der Windt, Wim AB Stalman, Theo PGM de Vries
BMC Family Practice , 2006, DOI: 10.1186/1471-2296-7-54
Abstract: To prevent or anticipate difficulties in N-of-1 trials, we argue that that it is important to individualise the outcome measures, and to carefully consider the objective, type of randomisation and the analysis. It is recommended to use the same dosages and dosage forms that the patient used before the trial, to start the trial with a run-in period, to formulate both general and individualised decision rules regarding the efficacy of treatment, to adjust treatment policies immediately after the trial, and to provide adequate instructions and support if treatment is adjusted.Because of the specific characteristics of N-of-1 trials it is difficult to formulate general 'how to do it' guidelines for designing N-of-1 trials. However, when the design of each N-of-1 trial is tailored to the specific characteristics of each individual patient and the underlying medical problem, most difficulties in N-of-1 trials can be prevented or overcome. In this way, N-of-1 trials may be of help when deciding on drug treatment for individual patients.In medical care, deciding on the optimal treatment for individual patients is one of the main concerns of the physician. Scientific evidence, recommendations from guidelines, medical expertise, patient preferences, and personal experiences all contribute to this decision process. Randomised controlled trials (RCTs) are generally considered to provide the strongest evidence for the efficacy of treatment. However, RCTs are designed to estimate an average treatment effect in a specific population [1]. In daily practice the physician has to determine the extent to which this average effect will apply to an individual patient. For instance, a patient who consults a physician may not be of a similar age, may have additional co-morbidity and medication, or may be interested in a different outcome compared to the subjects studied in the related RCT.Usually, when a physician doubts the applicability of treatment recommendations (derived from RCTs) to
Randomised controlled trial of tailored interventions to improve the management of anxiety and depressive disorders in primary care
Henny Sinnema, Gerdien Franx, Danille Volker, Cristina Majo, Berend Terluin, Michel Wensing, Anton van Balkom
Implementation Science , 2011, DOI: 10.1186/1748-5908-6-75
Abstract: In this cluster randomised controlled trial, a total of 22 general practices will be assigned to one of two conditions: (1) training, feedback, and tailored interventions and (2) training and feedback. The primary outcome measure is the proportion of patients who have been recognised to have anxiety and/or depressive disorder. The secondary outcome measures in patients are severity of anxiety and depressive symptoms, level of functioning, expectation towards and experience with care, quality of life, and economic costs. Measures are taken after the start of the intervention at baseline and at three- and six-month follow-ups. Secondary outcome measures in general practitioners are adherence to guideline-recommended care in care that has been delivered, the proportion of antidepressant prescriptions, and number of referrals to specialised mental healthcare facilities. Data will be gathered from the electronic medical patient records from the patients included in the study. In a process evaluation, the identification of barriers to change and the relations between prospectively identified barriers and improvement interventions selected for use will be described, as well as the factors that influence the provision of guideline-recommended care.It is hypothesised that the adherence to guideline recommendations will be improved by designing implementation interventions that are tailored to prospectively identified barriers in the local context of general practitioners. Currently, there is insufficient evidence on the most effective and efficient approaches to tailoring, including how barriers should be identified and how interventions should be selected to address the barriers.NTR1912Anxiety and depressive disorders are common mental disorders that have a negative impact on everyday functioning, cause great suffering, and incur both high healthcare costs and additional costs associated with production losses [1-3]. The lifetime prevalence of anxiety and depressive disorde
Design of a study on suboptimal cognitive acts in the diagnostic process, the effect on patient outcomes and the influence of workload, fatigue and experience of physician
Laura Zwaan, Abel Thijs, Cordula Wagner, Gerrit van der Wal, Danille RM Timmermans
BMC Health Services Research , 2009, DOI: 10.1186/1472-6963-9-65
Abstract: The research questions were addressed using several data sources. First, the differential diagnosis was assessed concurrently to the diagnostic process. Second, the patient records of 248 patients suffering from shortness of breath were reviewed by expert internists in order to reveal suboptimal cognitive acts and (potential) consequences for the patient. The suboptimal cognitive acts were discussed with the treating physicians and classified with the taxonomy of unsafe acts. Third, workload, fatigue and work experience were measured during the physicians work. Workload and fatigue were measured during the physicians shift using the NASA tlx questionnaire on a handheld computer. Physicians participating in the study also answered questions about their work experience.The design used in this study provides insight into the relationship between suboptimal cognitive acts in the diagnostic process and possible consequences for the patient. Suboptimal cognitive acts in the diagnostic process and its causes can be revealed. Additional measurements of workload, fatigue and experience allow examining the influence of these factors on the diagnostic process. In conclusion, the present design provides a method with which insights in weaknesses of the diagnostic process and the effect on patient outcomes can be studied and opportunities for improvement can be obtained.In order to deliver good quality of care a correct diagnosis based on complaints and symptoms of a patient is required. Physicians arrive at a diagnosis based on the patients' history, a physical examination and additional information such as results of laboratory tests and imaging techniques. From a large amount of information the physician has to select the information relevant for diagnosing the patient correctly. Based on this information different diagnoses are considered, investigated and subsequently confirmed or ruled out. Sometimes, this is a relatively simple task while in other cases it is complicated
Gentamicin release from commercially-available gentamicin-loaded PMMA bone cements in a prosthesis-related interfacial gap model and their antibacterial efficacy
Danille Neut, Otto S Kluin, Jonathan Thompson, Henny C van der Mei, Henk J Busscher
BMC Musculoskeletal Disorders , 2010, DOI: 10.1186/1471-2474-11-258
Abstract: 200 μm-wide gaps were made in samples of each cement and filled with buffer in order to measure the gentamicin release. Release kinetics were related to bone cement powder particle characteristics and wettabilities of the cement surfaces. Gaps were also inoculated with bacteria isolated from infected prostheses for 24 h and their survival determined. Gentamicin release and bacterial survival were statistically analysed using the Student's t-test.All three Palacos variants showed equal burst releases but each of the successor Palacos cements showed significantly higher sustained releases. SmartSet GHV showed a significantly higher burst release, while its sustained release was comparable with original Palacos. A gentamicin-sensitive bacterium did not survive in the high gentamicin concentrations in the interfacial gaps, while a gentamicin-resistant strain did, regardless of the type of cement used. Survival was independent of the level of burst release by the bone cement.Although marketed as the original gentamicin-loaded Palacos cement, orthopaedic surgeons should be aware that the successor cements do not appear to have the same release characteristics as the original one. Overall, high gentamicin concentrations were reached inside our prosthesis-related interfacial gap model. These concentrations may be expected to effectively decontaminate the prosthesis-related interfacial gap directly after implantation, provided that these bacteria are sensitive for gentamicin.Deep infections in a total joint replacement are potentially catastrophic events for patients. Antibiotic-loaded PMMA bone cements (ALBCs) are used in joint replacement procedures to fix implants, with the antibiotic acting to reduce the risk of infection. Surgeons have been mixing antibiotics into bone cement, but mixing antibiotics intra-operatively into carefully composed bone cement formulas presents certain risks. For example, the surgeon can never be sure that the antibiotic is evenly distributed t
Effectiveness of manual therapy compared to usual care by the general practitioner for chronic tension-type headache: design of a randomised clinical trial
René F Castien, Danille AWM van der Windt, Joost Dekker, Bert Mutsaers, Anneke Grooten
BMC Musculoskeletal Disorders , 2009, DOI: 10.1186/1471-2474-10-21
Abstract: We present the design of a randomised clinical trial (RCT) evaluating the effectiveness of manual therapy (MT) compared to usual care by the general practitioner (GP) in patients with CTTH.Patients are eligible for participation if they present in general practice with CTTH according to the classification of the International Headache Society (IHS).Participants are randomised to either usual GP care according to the national Dutch general practice guidelines for headache, or manual therapy, consisting of mobilisations (high- and low velocity techniques), exercise therapy for the cervical and thoracic spine and postural correction. The primary outcome measures are the number of headache days and use of medication. Secondary outcome measures are severity of headache, functional status, sickness absence, use of other healthcare resources, active cervical range of motion, algometry, endurance of the neckflexor muscles and head posture. Follow-up assessments are conducted after 8 and 26 weeks.This is a pragmatic trial in which interventions are offered as they are carried out in everyday practice. This increases generalisability of results, but blinding of patients, GPs and therapists is not possible.The results of this trial will contribute to clinical decision making of the GP regarding referral to manual therapy in patients with chronic tension headache.The 1-year prevalence of Chronic Tension-Type Headache (CTTH) is about 2–5% in the general population. In half of the CTTH cases, headache-related impairment in work performance is reported. [1,2] In addition to considerable impact on daily functioning and work participation, CTTH is a risk factor for overuse of analgesic medication [3]. Only about 20% of the CTTH patients seek medical care for their headache. This low consultation rate may be explained by insufficient information on the effectiveness of treatments or by previous negative health care experiences.[1,4]In primary care treatment for patients with CTTH is
Costs of shoulder pain in primary care consulters: a prospective cohort study in The Netherlands
Ton Kuijpers, Maurits W van Tulder, Geert JMG van der Heijden, Lex M Bouter, Danille AWM van der Windt
BMC Musculoskeletal Disorders , 2006, DOI: 10.1186/1471-2474-7-83
Abstract: A prospective cohort study consisting of 587 patients with a new episode of shoulder pain was conducted with a follow-up period of 6 months. Data on costs were collected by means of a cost diary during 6 months.84% of the patients completed all cost diaries. The mean consumption of direct health care and non-health related care was low. During 6 months after first consultation for shoulder pain, the mean total costs a patient generated were €689. Almost 50% of this total concerned indirect costs, caused by sick leave from paid work. A small proportion (12%) of the population generated 74% of the total costs.The total costs in the 6 months after first consultation for shoulder pain in primary care, mostly generated by a small part of the population, are not alarmingly high.Shoulder pain is common with a one-year prevalence ranging between 5% and 47%[1-6]. The prevalence in the general population in The Netherlands has recently been estimated at 17% [7]. The annual incidence of shoulder pain in Dutch general practice ranges between 12 and 25/1000/year [7-9]. Shoulder pain has an unfavourable outcome in many patients. About 40 to 50% of all patients who present with a new episode of shoulder pain in primary care report persistent symptoms after 6 to 12 months [10-12].Musculoskeletal disorders are the second most expensive disease group for health care costs in the Netherlands, and represent 6% of the total healthcare costs [13]. Information on the costs associated with health care use and loss of productivity in patients with shoulder pain is very scarce, especially for the large majority of patients who are treated in primary health care.We performed a cohort study among patients who presented shoulder pain to their general practitioner, and followed them for 6 months. Our objective was to determine the shoulder pain related costs during the 6 months following first consultation for their complaints in general practice.Between January 2001 and June 2003, 103 general p
The Effect of Trim5 Polymorphisms on the Clinical Course of HIV-1 Infection
Danille van Manen,Maarten A. N Rits,Corrine Beugeling,Karel van Dort,Hanneke Schuitemaker,Neeltje A Kootstra
PLOS Pathogens , 2008, DOI: 10.1371/journal.ppat.0040018
Abstract: The antiviral factor tripartite interaction motif 5α (Trim5α) restricts a broad range of retroviruses in a species-specific manner. Although human Trim5α is unable to block HIV-1 infection in human cells, a modest inhibition of HIV-1 replication has been reported. Recently two polymorphisms in the Trim5 gene (H43Y and R136Q) were shown to affect the antiviral activity of Trim5α in vitro. In this study, participants of the Amsterdam Cohort studies were screened for polymorphisms at amino acid residue 43 and 136 of the Trim5 gene, and the potential effects of these polymorphisms on the clinical course of HIV-1 infection were analyzed. In agreement with the reported decreased antiviral activity of Trim5α that contains a Y at amino acid residue 43 in vitro, an accelerated disease progression was observed for individuals who were homozygous for the 43Y genotype as compared to individuals who were heterozygous or homozygous for the 43H genotype. A protective effect of the 136Q genotype was observed but only after the emergence of CXCR4-using (X4) HIV-1 variants and when a viral load of 104.5 copies per ml plasma was used as an endpoint in survival analysis. Interestingly, naive CD4 T cells, which are selectively targeted by X4 HIV-1, revealed a significantly higher expression of Trim5α than memory CD4 T cells. In addition, we observed that the 136Q allele in combination with the ?2GG genotype in the 5′UTR was associated with an accelerated disease progression. Thus, polymorphisms in the Trim5 gene may influence the clinical course of HIV-1 infection also underscoring the antiviral effect of Trim5α on HIV-1 in vivo.
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