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Search Results: 1 - 10 of 548 matches for " Roel Vermeulen "
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Plasma Cytokine Concentrations in Workers Exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)
Fatemeh Saberi Hosnijeh,Roel Vermeulen
Frontiers in Oncology , 2012, DOI: 10.3389/fonc.2012.00037
Abstract: Objectives: Few epidemiological studies have studied the effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on blood cytokine levels. In this study we investigated changes in plasma levels of a large panel of cytokines, chemokines, and growth factors among workers from a Dutch historical cohort occupationally exposed to chlorophenoxy herbicides and contaminants including TCDD. Methods: Eighty-five workers who had been exposed to either high (n = 47) or low (n = 38) TCDD levels more than 30 years before serum collection were included in the current investigation. Plasma level of 16 cytokines, 10 chemokines, and 6 growth factors were measured. Current plasma levels of TCDD (TCDDcurrent) were determined by high-resolution gas chromatography/isotope-dilution high-resolution mass spectrometry. TCDD blood levels at the time of last exposure (TCDDmax) were estimated using a one-compartment first order kinetic model. Results: Blood levels of most analytes had a negative association with current and estimated past maximum TCDD levels. These decreases reached formal statistical significance for fractalkine, transforming growth factor alpha (TGF-α), and fibroblast growth factor 2 (FGF2) with increasing TCDD levels. Conclusion: Our study showed a general reduction in most analyte levels with the strongest effects for fractalkine, FGF2, and TGF-α. These findings suggest that TCDD exposure could suppress the immune system and that chemokine and growth factor-dependent cellular pathway changes by TCDD may play role in TCDD toxicity and associated health effects.
The impact of new research technologies on our understanding of environmental causes of disease: the concept of clinical vulnerability
Paolo Vineis, Aneire E Khan, Jelle Vlaanderen, Roel Vermeulen
Environmental Health , 2009, DOI: 10.1186/1476-069x-8-54
Abstract: We are still far from completely understanding the etiology and causal patterns for many common diseases, such as breast and colon cancer, or neurodegenerative diseases. In spite of decades of epidemiological research, the etiology of many such conditions is still largely unknown.For a long time it has been hypothesized that most chronic diseases have an environmental origin (using the term "environment" in a broad sense, to indicate essentially what is not due to genetic predisposition). This claim was based on descriptive data showing the broad range of incidence rates in different parts of the world, the rapid temporal changes - such as those currently occurring in China and India - and the crucial observation of incidence rates in migrant populations. The latter unequivocally showed that migrants rapidly acquire - sometimes already in the first generation after migration - the risk of disease that is typical of the population where they move.However, "environmental" risks have been largely elusive in epidemiological research, and there is still much debate on the real impact of the environment, whose role tends to be overshadowed in recent times by the successes of genetics, in particular Genome-wide association studies (GWAS). Clearly, we need a disease model that allows us to encompass both the mass of genetic data coming from GWAS and the still elusive role of many environmental exposures.The technological revolution in genetics, which in 2007-2009 led to the identification of a number of novel genes for several common diseases, is inspiring but at the same time a little disappointing. Most highly-penetrant genes had already been uncovered by linkage studies, so that "genome-wide scans" could mainly identify low-penetrant genes. It is a fact that - with a few exceptions - what has been found is genetic variants weakly associated with chronic diseases, with relative risks of 1.15-1.5. These risks are much lower than some known environmental exposures, and of t
Respiratory symptoms and occupation: a cross-sectional study of the general population
Roel Vermeulen, Dick Heederik, Hans Kromhout, Henri?tte A Smit
Environmental Health , 2002, DOI: 10.1186/1476-069x-1-5
Abstract: The study subjects (aged 20–59) were all inhabitants of Doetinchem, a small industrial town, and came from a survey of a random sample of 1104 persons conducted in 1993. A total of 274 cases with respiratory symptoms (subdivided in asthma and bronchitis symptoms) and 274 controls without symptoms were matched for age and sex. Relations between industry and occupation and respiratory symptoms were explored and adjusted for smoking habits and social economic status.Employment in the 'construction' (OR = 3.38; 95%CI 1.02 – 11.27), 'metal' (OR = 3.17; 95%CI 0. 98 – 10.28), 'rubber, plastics and synthetics' (OR = 6.52; 95%CI 1.26 – 53.80), and 'printing' industry (OR = 3.96; 95%CI 0.85 – 18.48) were positively associated with chronic bronchitis symptoms. In addition, the 'metal' industry was found to be weakly associated with asthma symptoms (OR = 2.59; 95%CI 0.87 – 7.69). Duration of employment within these industries was also positively associated with respiratory symptoms.Respiratory symptoms in the general population are traceable to employment in particular industries even in a contemporary cohort with relatively young individuals.Respiratory diseases such as asthma, bronchitis and emphysema form a major health problem in the general population in many western countries [1,2]. The evidence that these diseases are caused by exogenous factors other than tobacco smoke, and that occupational exposures are amongst these causes, is growing [3]. As the working population smokes less, the relative importance of occupational exposures causing respiratory diseases is likely to increase. The contribution of occupational exposure to respiratory diseases has been estimated at 11–19% for males and 4–5% for females [1,2,4,5].The relationships between occupation and occupational exposures and respiratory symptoms in community-based studies have been studied since the late 1970s. In many of these general population studies, an association with exposure to dust, gases and fumes has b
Decreased Numbers of CD4+ Naive and Effector Memory T Cells, and CD8+ Na?ve T Cells, are Associated with Trichloroethylene Exposure
H. Dean Hosgood III,Roel Vermeulen,Qing Lan
Frontiers in Oncology , 2012, DOI: 10.3389/fonc.2011.00053
Abstract: Trichloroethylene (TCE) is a volatile chlorinated organic compound that is commonly used as a solvent for lipophilic compounds. Although recognized as an animal carcinogen, TCE’s carcinogenic potential in humans is still uncertain. We have carried out a cross-sectional study of 80 workers exposed to TCE and 96 unexposed controls matched on age and sex in Guangdong, China to study TCE’s early biologic effects. We previously reported that the total lymphocyte count and each of the major lymphocyte subsets (i.e., CD4+ T cells, CD8+ T cells, natural killer cells, and B cells) were decreased in TCE-exposed workers compared to controls, suggesting a selective effect on lymphoid progenitors, and/or lymphocyte survival. To explore which T lymphocyte subsets are affected in the same study population, we investigated the effect of TCE exposure on the numbers of CD4+ na?ve and memory T cells, CD8+ na?ve and memory T cells, and regulatory T cells by FACS analysis. Linear regression of each subset was used to test for differences between exposed workers and controls adjusting for potential confounders. We observed that CD4+ and CD8+ na?ve T cell counts were about 8% (p = 0.056) and 17% (p = 0.0002) lower, respectively, among exposed workers. CD4+ effector memory T cell counts were decreased by about 20% among TCE-exposed workers compared to controls (p = 0.001). The selective targeting of TCE on CD8+ naive and possibly CD4+ naive T cells, and CD4+ effector memory T cells, provide further insights into the immunosuppression-related response of human immune cells upon TCE exposure.
Coding Issues in Cognitive Mapping of Games  [PDF]
Roel Popping
Open Journal of Political Science (OJPS) , 2013, DOI: 10.4236/ojps.2013.31003

In text analysis studies coders have to make qualitative decisions. These decisions are based on interpretations of the texts under study. In such situations it is very helpful to have coding rules. These do not only help as an aid to the coder, but are also useful for readers of the research report that will follow. The rules make visible in considerable extent how the coding task has been performed, they take care of transparency. This contribution focuses on motions that have been treated in the Dutch House of Representatives. Motions usually contain information on why they are needed, the proposing member usually also tells about it. There is a discussion with the secretary, who is supposed to put the motion into effect if it is accepted. The secretary even has to give an advice. It is assumed that under these discussion(s) a cognitive map containing some game theoretic representation can be found. Rules are discussed that are used to code the types of maps that might be found.

Hierarchical Regression for Multiple Comparisons in a Case-Control Study of Occupational Risks for Lung Cancer
Marine Corbin, Lorenzo Richiardi, Roel Vermeulen, Hans Kromhout, Franco Merletti, Susan Peters, Lorenzo Simonato, Kyle Steenland, Neil Pearce, Milena Maule
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0038944
Abstract: Background Occupational studies often involve multiple comparisons and therefore suffer from false positive findings. Semi-Bayes adjustment methods have sometimes been used to address this issue. Hierarchical regression is a more general approach, including Semi-Bayes adjustment as a special case, that aims at improving the validity of standard maximum-likelihood estimates in the presence of multiple comparisons by incorporating similarities between the exposures of interest in a second-stage model. Methodology/Principal Findings We re-analysed data from an occupational case-control study of lung cancer, applying hierarchical regression. In the second-stage model, we included the exposure to three known lung carcinogens (asbestos, chromium and silica) for each occupation, under the assumption that occupations entailing similar carcinogenic exposures are associated with similar risks of lung cancer. Hierarchical regression estimates had smaller confidence intervals than maximum-likelihood estimates. The shrinkage toward the null was stronger for extreme, less stable estimates (e.g., “specialised farmers”: maximum-likelihood OR: 3.44, 95%CI 0.90–13.17; hierarchical regression OR: 1.53, 95%CI 0.63–3.68). Unlike Semi-Bayes adjustment toward the global mean, hierarchical regression did not shrink all the ORs towards the null (e.g., “Metal smelting, converting and refining furnacemen”: maximum-likelihood OR: 1.07, Semi-Bayes OR: 1.06, hierarchical regression OR: 1.26). Conclusions/Significance Hierarchical regression could be a valuable tool in occupational studies in which disease risk is estimated for a large amount of occupations when we have information available on the key carcinogenic exposures involved in each occupation. With the constant progress in exposure assessment methods in occupational settings and the availability of Job Exposure Matrices, it should become easier to apply this approach.
A Case-Control Study of the Protective Effect of Alcohol, Coffee, and Cigarette Consumption on Parkinson Disease Risk: Time-Since-Cessation Modifies the Effect of Tobacco Smoking
Marianne van der Mark, Peter C. G. Nijssen, Jelle Vlaanderen, Anke Huss, Wim M. Mulleners, Antonetta M. G. Sas, Teus van Laar, Hans Kromhout, Roel Vermeulen
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0095297
Abstract: The aim of this study was to investigate the possible reduced risk of Parkinson Disease (PD) due to coffee, alcohol, and/or cigarette consumption. In addition, we explored the potential effect modification by intensity, duration and time-since-cessation of smoking on the association between cumulative pack-years of cigarette smoking (total smoking) and PD risk. Data of a hospital based case-control study was used including 444 PD patients, diagnosed between 2006 and 2011, and 876 matched controls from 5 hospitals in the Netherlands. A novel modeling method was applied to derive unbiased estimates of the potential modifying effects of smoking intensity, duration, and time-since-cessation by conditioning on total exposure. We observed no reduced risk of PD by alcohol consumption and only a weak inverse association between coffee consumption and PD risk. However, a strong inverse association of total smoking with PD risk was observed (OR = 0.27 (95%CI: 0.18–0.42) for never smokers versus highest quartile of tobacco use). The observed protective effect of total smoking was significantly modified by time-since-cessation with a diminishing protective effect after cessation of smoking. No effect modification by intensity or duration of smoking was observed indicating that both intensity and duration have an equal contribution to the reduced PD risk. Understanding the dynamics of the protective effect of smoking on PD risk aids in understanding PD etiology and may contribute to strategies for prevention and treatment.
Anker Brink Lund, Lars Nord & Johann Roppen: Nye udfordringer for gamle medier. Skandinavisk public service i det 21. rhundre. G teborg: NORDICOM. 2009. Anker Brink Lund, Lars Nord & Johann Roppen: Nye udfordringer for gamle medier. Skandinavisk public service i det 21. rhundre. G teborg: NORDICOM. 2009.
Roel Puijk
MedieKultur : Journal of Media and Communication Research , 2010,
Participatie in veelvoud
Roel Kuiper
Journal of Social Intervention : Theory and Practice , 2008,
STrengthening the Reporting of OBservational studies in Epidemiology – Molecular Epidemiology (STROBE-ME): An Extension of the STROBE Statement
Valentina Gallo ,Matthias Egger,Valerie McCormack,Peter B. Farmer,John P. A. Ioannidis,Micheline Kirsch-Volders,Giuseppe Matullo,David H. Phillips,Bernadette Schoket,Ulf Stromberg,Roel Vermeulen,Christopher Wild,Miquel Porta,Paolo Vineis
PLOS Medicine , 2011, DOI: 10.1371/journal.pmed.1001117
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