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Search Results: 1 - 10 of 489696 matches for " Merel F. M. Langelaar "
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Prioritizing Emerging Zoonoses in The Netherlands
Arie H. Havelaar,Floor van Rosse,Catalin Bucura,Milou A. Toetenel,Juanita A. Haagsma,Dorota Kurowicka,J. (Hans) A. P. Heesterbeek,Niko Speybroeck,Merel F. M. Langelaar,Johanna W. B. van der Giessen,Roger M. Cooke,Marieta A. H. Braks
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0013965
Abstract: To support the development of early warning and surveillance systems of emerging zoonoses, we present a general method to prioritize pathogens using a quantitative, stochastic multi-criteria model, parameterized for the Netherlands.
Ethanol Lock Therapy as additional treatment of catheter-related bloodstream infections in pediatric patients receiving home parenteral nutrition  [PDF]
Merel N. van Kassel, Dasja Pajkrt, Jim C. H. Wilde, Cora F. Jonkers, Merit M. Tabbers
Open Journal of Pediatrics (OJPed) , 2013, DOI: 10.4236/ojped.2013.34072

Background: Catheter related bloodstream infections (CRIs) are a major cause of morbidity, mortality and prolonged hospitalization in pediatric patients with home parenteral nutrition (HPN). In recent years, new prophylactic and treatment options have been evaluated to reduce the incidence of CRIs and infection related catheter removals. In children, two retrospective studies have shown the efficacy of ethanol lock treatment (ELT) in reducing the incidence of CRIs in pediatric oncology patients. However, prospective data are missing. Our aim of the present study was to evaluate prospectively the effect of ELT on the cure and recurrence rate of CRIs, duration of hospitalization and antibiotic use in HPN pediatric patients. Methods: HPN children older than three months with a clinical suspicion of a CRI were included and randomised to ELT or standard flushing treatment (heparin or taurolidine). The primary outcomes were persistence and recurrence of the bacteraemia and Central Venous Access Device (CVAD) removal. Secondary outcomes included duration of antibiotic use, duration of hospitalization and side effects. Results: Data from eight HPN children experiencing 14 suspected CRI were analysed. Seven patients had proven CRIs by positive blood cultures. Four were treated with ELT and three with their standard flushing treatment. One CRI persisted in the control group. In one single patient, bacteraemia recurred three times within 24 weeks. This patient had been enrolled in both study arms. A CVAD removal was needed in one patient because of occlusion. Conclusions: This small study showed no additional efficacy of the use of ELT on cure rate or recurrences of CRIs compared to standard therapy in HPN treated children. There were also no differences in duration of hospitalization, the use of antibiotics or CVAD removal between both groups.

Gastrointestinal Symptoms are Still Prevalent and Negatively Impact Health-Related Quality of Life: A Large Cross-Sectional Population Based Study in The Netherlands
Merel M. Tielemans, Jeroen Jaspers Focks, Leo G. M. van Rossum, Ties Eikendal, Jan B. M. J. Jansen, Robert J. F. Laheij, Martijn G. H. van Oijen
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0069876
Abstract: Background Over the last decades important risk factors for gastrointestinal symptoms have shifted, which may have changed its population prevalence. The aim of this study was to assess the current prevalence of gastrointestinal symptoms, appraise associated factors and assess health-related quality of life in the general population. Methods A total of 51,869 questionnaires were sent to a representative sample of the Dutch adult general population in December 2008. Demographic characteristics, gastrointestinal symptoms, health-related quality of life, medication use and co-morbidity were reported. We used multivariable logistic regression analysis to determine factors associated with gastrointestinal symptoms. Results A total of 18,317 questionnaires were returned, and 16,758 were eligible for analysis. Prevalence of gastrointestinal symptoms was 26%. Most frequent symptoms were bloating (63%), borborygmi (60%) and flatulence (71%). Female gender (adjusted OR (aOR) 1.59, 95% CI 1.43–1.77), asthma/COPD (aOR 1.47, 95% CI 1.21–1.79), use of paracetamol (aOR 1.33, 95% CI 1.20–1.47), antidepressants (aOR 1.56, 95% CI 1.22–2.00) and acid-suppressive medication were independently associated with presence of gastrointestinal symptoms. Age over 65 years (aOR 0.75, 95% CI 0.65–0.87), and use of statins (aOR 0.75, 95% CI 0.61–0.93) were associated with a lower prevalence of gastrointestinal symptoms. Respondents with gastrointestinal symptoms had a lower mean health-related quality of life of 0.81 (SD = 0.21) compared to 0.92 (SD = 0.14) for persons without gastrointestinal symptoms (P<0.01). Conclusions Prevalence of gastrointestinal symptoms in the Dutch community is high and associated with decreased health-related quality of life.
Toxicity and Viral Load in Urine during Valganciclovir Therapy in Premature Infants  [PDF]
Merel Boesveld, Henrica L. M. Van Straaten, Marieke A. C. Hemels
Pharmacology & Pharmacy (PP) , 2017, DOI: 10.4236/pp.2017.88020
Cytomegalovirus (CMV) infection is the most important cause of mental retardation and sensorineural hearing loss. Antiviral treatment with valganciclovir, a relatively new but potential toxic oral drug, is recommended to prevent further hearing deterioration. In this retrospective cohort study we evaluated the relation between the dose of valganciclovir and the reduction of CMV viral load, as well as the toxicity. All neonates with gestational age <32 weeks with CMV infection treated with oral valganciclovir (30 mg/kg/day) were included. Time interval to reach CMV viral load below detection level (<250 copies/ml) was determined. Toxicity was measured by plasma trough levels, thrombocytopenia and leukopenia. Data of 6 infants, median gestational age 252 weeks, were analyzed. Time interval between start of therapy and viral load below detection level was 25 - 54 days. In total, 37 through plasma samples were analyzed. Of these, 28 were in the normal range, 3 above and 6 under the target concentration. Mild transient leukopenia occurred in 1 infant. No thrombocytopenia occurred. Conclusion: Antiviral treatment of CMV infection with oral valganciclovir results in adequate plasma through levels. Also, a progressive reduction of viral load in the urine below detection level was reached within 25 - 54 days, without serious short time side effects.
Encoder-Decoder Optimization for Brain-Computer Interfaces
Josh Merel,Donald M. Pianto?,John P. Cunningham?,Liam Paninski
PLOS Computational Biology , 2015, DOI: 10.1371/journal.pcbi.1004288
Abstract: Neuroprosthetic brain-computer interfaces are systems that decode neural activity into useful control signals for effectors, such as a cursor on a computer screen. It has long been recognized that both the user and decoding system can adapt to increase the accuracy of the end effector. Co-adaptation is the process whereby a user learns to control the system in conjunction with the decoder adapting to learn the user's neural patterns. We provide a mathematical framework for co-adaptation and relate co-adaptation to the joint optimization of the user's control scheme ("encoding model") and the decoding algorithm's parameters. When the assumptions of that framework are respected, co-adaptation cannot yield better performance than that obtainable by an optimal initial choice of fixed decoder, coupled with optimal user learning. For a specific case, we provide numerical methods to obtain such an optimized decoder. We demonstrate our approach in a model brain-computer interface system using an online prosthesis simulator, a simple human-in-the-loop pyschophysics setup which provides a non-invasive simulation of the BCI setting. These experiments support two claims: that users can learn encoders matched to fixed, optimal decoders and that, once learned, our approach yields expected performance advantages.
Working Memory Capacity, Inhibitory Control and the Role of L2 Proficiency in Aging L1 Dutch Speakers of Near-Native L2 English
Merel Keijzer
Brain Sciences , 2013, DOI: 10.3390/brainsci3031261
Abstract: This paper examines the intricate relationship between working memory (WM) capacity and inhibitory control as a function of both L2 proficiency and age. In both its design and research questions, this study closely follows Gass & Lee’s work, where both L1 and L2 Reading Span Tasks (as measures of WM capacity) and L1 and L2 Stroop interference tasks (to measure inhibitory control) were administered. In this study, the test battery is augmented by both an L1 and L2 C-test of overall language proficiency. Participants were 63 L1 Dutch speakers of L2 English, who had been immersed in an L2 environment for a considerable amount of time. Their data were set off against those of 54 monolingual Dutch speakers and 56 monolingual English speakers. At the time of testing, all the bilingual participants had a near-native command of English and their L1 and L2 WM scores were not found to be significantly different. However, discrepancies did occur in Stroop test scores of inhibition, where the bilinguals performed better in their L2 English than L1 Dutch. These main effects often contradicted the results found in Gass & Lee’s study, who examined less proficient L2 learners. An aging effect was furthermore found: older subjects consistently performed more poorly on WM and inhibition tasks than their younger peers. These results can shed light on how individual factors like WM capacity and inhibitory control interact in successful late bilinguals and how these dynamics shift with advanced age.
A decision-analytic approach to define poor prognosis patients: a case study for non-seminomatous germ cell cancer patients
Merel R van Dijk, Ewout W Steyerberg, J Dik F Habbema
BMC Medical Informatics and Decision Making , 2008, DOI: 10.1186/1472-6947-8-1
Abstract: We used published literature to estimate the benefit and harm of high-dose chemotherapy (HD-CT) versus standard-dose chemotherapy (SD-CT) for patients with advanced non-seminomatous germ cell cancer. Benefit and harm were defined as the reduction and increase in absolute risk of mortality due to HD-CT respectively. Harm included early and late treatment related death, and treatment related morbidity (weighted by 'utility').We considered a conservative and an optimistic benefit of 30 and 40% risk reduction respectively. We estimated the excess treatment related mortality at 2%. When treatment related morbidity was taken into account, the harm of HD-CT increased to 5%. With a relative benefit of 30% and harm of 2 or 5%, HD-CT might be beneficial for patients with over 7 or 17% risk of cancer specific mortality with SD chemotherapy, while with a relative benefit of 40% HD-CT was beneficial over 5 and 12.5% risk respectively. Compared to the IGCC classification 14% of the patients would receive more aggressive treatment, and 2% less intensive treatment.Benefit and harm can be used to define 'poor prognosis' explicitly for non-seminomatous germ cell cancer patients who are considered for high-dose chemotherapy. This approach can readily be adapted to new results and extended to other cancers to define candidates for more aggressive treatments.The prognosis of a cancer patient is of key importance in the choice of more or less aggressive treatment. Prognostic estimates can be based on extent of disease, as for example reflected in TNM stage, on age and comorbidity, and on specific characteristics, such as values of tumour markers [1]. Prognostic classifications can facilitate decision-making by grouping patients with a similar prognosis. Poor prognosis patients may be considered candidates for more aggressive treatment strategies, while good prognosis patients may be treated with less burdensome interventions, for example by less toxic chemotherapy regimens [2,3]. Prognos
Relaxation Acupressure Reduces Persistent Cancer-Related Fatigue
Suzanna M. Zick,Sara Alrawi,Gary Merel,Brodie Burris,Ananda Sen,Amie Litzinger,Richard E. Harris
Evidence-Based Complementary and Alternative Medicine , 2011, DOI: 10.1155/2011/142913
Abstract: Persistent cancer-related fatigue (PCRF) is a symptom experienced by many cancer survivors. Acupressure offers a potential treatment for PCRF. We investigated if acupressure treatments with opposing actions would result in differential effects on fatigue and examined the effect of different “doses” of acupressure on fatigue. We performed a trial of acupressure in cancer survivors experiencing moderate to severe PCRF. Participants were randomized to one of three treatment groups: relaxation acupressure (RA), high-dose stimulatory acupressure (HIS), and low-dose stimulatory acupressure (LIS). Participants performed acupressure for 12-weeks. Change in fatigue as measured by the Brief Fatigue Inventory (BFI) was our primary outcome. Secondary outcomes were assessment of blinding and compliance to treatment. Fatigue was significantly reduced across all treatment groups (mean ± SD reduction in BFI: RA 4.0±1.5, HIS 2.2±1.6, LIS 2.7±2.2), with significantly greater reductions in the RA group. In an adjusted analysis, RA resulted in significantly less fatigue after controlling for age, cancer type, cancer stage, and cancer treatments. Self-administered RA caused greater reductions in fatigue compared to either HIS or LIS. The magnitude of the reduction in fatigue was clinically relevant and could represent a viable alternative for cancer survivors with PCRF.
Fear Inhibition in High Trait Anxiety
Merel Kindt, Marieke Soeter
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0086462
Abstract: Trait anxiety is recognized as an individual risk factor for the development of anxiety disorders but the neurobiological mechanisms remain unknown. Here we test whether trait anxiety is associated with impaired fear inhibition utilizing the AX+/BX- conditional discrimination procedure that allows for the independent evaluation of startle fear potentiation and inhibition of fear [1]. Sixty undergraduate students participated in the study - High Trait Anxious: n = 28 and Low Trait Anxious: n = 32. We replicated earlier findings that a transfer of conditioned inhibition for startle responses requires contingency awareness. However, contrary to the fear inhibition hypothesis, our data suggest that high trait anxious individuals show a normal fear inhibition of conditioned startle responding. Only at the cognitive level the high trait anxious individuals showed evidence for impaired inhibitory learning of the threat cue. Together with other findings where impaired fear inhibition was only observed in those PTSD patients who were either high on hyperarousal symptoms [2] or with current anxiety symptoms [3], we question whether impaired fear inhibition is a biomarker for the development of anxiety disorders.
High Trait Anxiety: A Challenge for Disrupting Fear Memory Reconsolidation
Marieke Soeter, Merel Kindt
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0075239
Abstract: Disrupting reconsolidation may be promising in the treatment of anxiety disorders but the fear-reducing effects are thus far solely demonstrated in the average organism. A relevant question is whether disrupting fear memory reconsolidation is less effective in individuals who are vulnerable to develop an anxiety disorder. By collapsing data from six previous human fear conditioning studies we tested whether trait anxiety was related to the fear-reducing effects of a pharmacological agent targeting the process of memory reconsolidation - n = 107. Testing included different phases across three consecutive days each separated by 24 h. Fear responding was measured by the eye-blink startle reflex. Disrupting the process of fear memory reconsolidation was manipulated by administering the β-adrenergic receptor antagonist propranolol HCl either before or after memory retrieval. Trait anxiety uniquely predicted the fear-reducing effects of disrupting memory reconsolidation: the higher the trait anxiety, the less fear reduction. Vulnerable individuals with the propensity to develop anxiety disorders may need higher dosages of propranolol HCl or more retrieval trials for targeting and changing fear memory. Our finding clearly demonstrates that we cannot simply translate observations from fundamental research on fear reduction in the average organism to clinical practice.
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