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Dive into the research topics where Paul Westers is active.

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Featured researches published by Paul Westers.


The Annals of Thoracic Surgery | 2001

Better ischemic event-free survival after two internal thoracic artery grafts: 13 years of follow-up

Eric Berreklouw; Phillip P.C Rademakers; Jurgen M Koster; Linda van Leur; Brigitte J.W van der Wielen; Paul Westers

BACKGROUND We researched our data to determine whether pedicled bilateral internal thoracic artery (BITA) grafting led to better ischemic event-free survival compared to single ITA grafting, at 10 years mean follow-up. METHODS Retrospectively 249 patients with BITAs with or without additional vein grafts (BITA group) were matched with 233 comparable patients with left ITA and additional vein grafts (LITA group), at a mean follow-up interval of 10 years. RESULTS At 13 years, 76.2% +/- 5.9% of the BITA and 78.3% +/- 3.8% of the LITA patients were still alive (p = not significant). Death, recurrent angina, new myocardial infarction, or coronary reinterventions occurred more often in LITA (49.4%) than BITA (33.3%) patients (p = 0.0004). The ischemic event-free survival estimates for BITA patients (47.5% +/- 8.4%) was better than for LITA patients (35.4% +/- 5.1%) (p < 0.001). Multivariate analysis showed that BITA was a predictor for ischemic event-free survival (p = 0.0005). CONCLUSIONS For the decision to use one or two ITAs the positive influence of BITA grafting on ischemic event-free survival is more important than its effect on survival, per se. Compared to the general strategy of BITA grafting, neither total arterial revascularization nor the specific vessels grafted with BITA is relevant for the ischemic event-free survival.


Journal of Ethnopharmacology | 2010

Why Surinamese migrants in the Netherlands continue to use medicinal herbs from their home country

Tinde van Andel; Paul Westers

AIM OF THE STUDY When people migrate, they tend to bring along their medicinal plants. In order to improve migrant health, we need information on their traditional health beliefs and practices. This paper investigates medicinal plant use among Surinamese migrants in the Netherlands. MATERIALS AND METHODS Data from 210 semi-structured interviews among 1st and 2nd generation Surinamese migrants were analysed to determine which medicinal plants were used, for what purposes, which demographic, socio-economic or psycho-social factors play a role in the choice for traditional medicine and to clarify peoples personal motives to use herbs. Variables associated with medicinal plant use were identified by using the Pearson gamma2 test and the two-sample t-test. After selecting significant variables by means of bivariate analyses, multinomial logistic regression with stepwise forward selection was used to assess whether medicinal plant use could be explained by a combination of these variables. RESULTS More than 75% of the respondents used herbal medicine, and 66% did so in the past year. Herbs were more frequently employed for health promotion (39%) than for disease prevention or cure (both 27%). Almost half of the respondents who had been ill the last year had used herbal medicine. More than 140 herb species were mentioned during the interviews. Plant use was often related to certain culture-bound health beliefs. Spiritual baths were the most popular traditional practice, followed by genital steam baths, bitter tonics, and the consumption of bitter vegetables. Afro-Surinamers more frequently used herbal medicine than Hindustani. The WINTI belief strongly influenced plant use, as well as the occurrence of an illness in the past year, and frequent visits to Suriname. Age, gender, income and education had no significant effect on the use of traditional medicine. Surinamers stated that they used medicinal herbs because they grew up with them; herbs were more effective and had fewer side effects than conventional therapies. CONCLUSIONS As long as certain culture-bound beliefs and health concepts remain prevalent among Surinamese migrants, and ties with their home country remain strong, they will continue using medicinal herbs from their country of origin. More research is needed on the health effects of frequently used medicinal plants by migrants in the Netherlands.


Schizophrenia Research | 2003

Cognitive dysfunctions in parents of schizophrenic patients parallel the deficits found in patients

Melanie C.M. Appels; Margriet M. Sitskoorn; Paul Westers; Elleke B. T. E. Lems; René S. Kahn

Schizophrenia is characterized by a global cognitive impairment, with varying degrees of deficit in all ability domains. Since genetic factors are important in the etiology of schizophrenia we investigated whether parents of schizophrenic patients also show cognitive deficits, particularly on those cognitive ability domains that are most severely affected in patients. Both biological parents of 37 patients with schizophrenia (N=74 subjects) and 28 comparable healthy married control couples (N=56 subjects) were included. A comprehensive and standardized cognitive battery was used including tests measuring verbal memory, executive functioning, language, attention, and psychomotor functioning. Parents of patients differed from control couples on those cognitive constructs that are generally considered to be most impaired in schizophrenic patients, i.e. global verbal memory, bilateral motor skill, continuous performance, and word fluency. In addition, parents differed significantly from control couples on some other cognitive constructs on which patients show a smaller but also significant difference compared to healthy controls, i.e. unilateral motor skill and digit span. Results suggest that the cognitive constructs on which patients show relatively most severe impairment may prove suitable as endophenotypic markers in schizophrenia.


European Urology | 2013

Prevalence, Incidence, and Resolution of Nocturnal Polyuria in a Longitudinal Community-based Study in Older Men: The Krimpen Study

Boris van Doorn; Marco H. Blanker; Esther T. Kok; Paul Westers; J.L.H. Ruud Bosch

BACKGROUND Nocturnal polyuria (NP) is common in older men and can lead to nocturia. However, no longitudinal data are available on the natural history of NP. OBJECTIVE To determine prevalence, incidence, and resolution rates of NP. DESIGN, SETTING, AND PARTICIPANTS A longitudinal, community-based study was conducted among 1688 men aged 50-78 yr in Krimpen aan den IJssel, The Netherlands (reference date: 1995), with planned follow-up rounds at 2, 4, and 6 yr. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS NP was determined with frequency-volume charts. Two definitions of NP were used: (1) a nocturnal urine production (NUP) of >90 ml/h (NUP90) and (2) the nocturnal voided volume plus first morning void being >33% of the 24-h voided volume (NUV33). Nocturia was defined as two or more voids per night. We determined the prevalence of NP at each study round. At first follow-up, we determined the incidence in men without baseline NP and the resolution in men with baseline NP. Prevalence of NP in men with or without nocturia was also determined. RESULTS AND LIMITATIONS At baseline, the prevalence of NUP90 was 15.0% and increased to 21.7% after 6.5 yr, whereas the prevalence of NUV33 was 77.8% at baseline and 80.5% after 6.5 yr. At 2.1 yr of follow-up, the incidences of NUP90 and NUV33 were 13.6% and 60.3%, respectively, and the resolution rates were 57.0% and 17.8%, respectively. Because of this fluctuation in NP, no reliable long-term incidences could be calculated. At baseline, NUP90 was prevalent in 27.7% of men with nocturia and in 8.0% of those without nocturia. At baseline, NUV33 was prevalent in 91.9% of men with nocturia and in 70.1% of men without nocturia. CONCLUSIONS Due to the fluctuation of NP, it is advisable to first determine its chronicity and cause before starting treatment. Because of the high prevalence of NP in men without nocturia, NUV33 should be reconsidered as a discriminative definition of NP.


The Journal of Pediatrics | 2009

Gastric Acid Inhibition for Fat Malabsorption or Gastroesophageal Reflux Disease in Cystic Fibrosis: Longitudinal Effect on Bacterial Colonization and Pulmonary Function

Hubert P.J. van der Doef; H.G.M. Arets; Steven P. Froeling; Paul Westers; Roderick H. J. Houwen

OBJECTIVES To investigate bacterial colonization and pulmonary function longitudinally in patients with cystic fibrosis (CF) receiving drugs for gastric acid (GA) inhibition for fat malabsorption or for gastroesophageal reflux disease (GERD). STUDY DESIGN A retrospective cohort study of 218 pediatric patients with CF was performed. Multilevel modeling was used to perform longitudinal analysis of forced expiratory volume in 1 second (FEV(1)), forced vital capacity (FVC), maximum expiratory flow at 50% of FVC (MEF(50)), and maximal mid-expiratory flow between 25% and 75% of FVC (MMEF(25-75)). Cox regression was used to calculate Pseudomonas aeruginosa- and Staphylococcus aureus-free survival. RESULTS Patients with CF and GA inhibition had a significantly smaller yearly decline of MEF(50) and MMEF(25-75) compared with control subjects. Other pulmonary function parameters and P aeruginosa or S aureus acquisition or colonization were not different from that of control subjects. GERD was associated with a significantly reduced pulmonary function (FEV(1) and FVC) and an earlier acquisition of P aeruginosa and S aureus. CONCLUSIONS GA inhibition did not affect pulmonary function or bacterial acquisition and therefore is not contraindicated in patients with CF. GA inhibition might improve pulmonary function with time, because the decline of MEF(50) and MMEF(25-75) was less pronounced. GERD was associated with a reduced pulmonary function and an earlier acquisition of P aeruginosa and S aureus. Therefore the diagnosis and treatment of GERD should be aggressively pursued in patients with CF.


The Journal of Urology | 2011

Once Nocturia, Always Nocturia? Natural History of Nocturia in Older Men Based on Frequency-Volume Charts: The Krimpen Study

Boris van Doorn; Marco H. Blanker; Esther T. Kok; Paul Westers; J.L.H. Ruud Bosch

PURPOSE Nocturia is a highly prevalent and bothersome symptom that might (spontaneously) resolve. However, longitudinal data are not available on the incidence and resolution of nocturia assessed with frequency-volume charts. In this study we determined the prevalence, incidence and resolution rates of nocturia assessed by frequency-volume charts, and compared nocturnal voiding frequency over time as assessed by frequency-volume charts and questionnaires. MATERIALS AND METHODS A longitudinal, population based study was conducted among 1,688 men 50 to 78 years old with followup rounds at 2.1, 4.2 and 6.5 years. Nocturnal voiding frequency was determined with frequency-volume charts and, for comparison purposes, with a question from the International Prostate Symptom Score. Nocturia was defined as nocturnal voiding frequency 2 or greater. Prevalence, incidence and resolution rates were also determined. RESULTS At the 2.1-year followup the incidence rate was 23.9% and the resolution rate was 36.7%. The incidence rate was highest in the oldest group (70 to 78 years) and lowest in the youngest (50 to 54 years), whereas the resolution rate was highest in the group 55 to 59 years old and lowest in the oldest group. Because of the high resolution rate, no reliable incidence rates can be calculated. Despite fluctuation, the prevalence of nocturia increased with age and over time (from 34.4% to 44.7% for the total group, p <0.05). Men who had a frequency-volume chart-nocturnal voiding frequency less than International Prostate Symptom Score-nocturnal voiding frequency (6% of the population) more often had this later on. CONCLUSIONS In this population frequency-volume chart assessed nocturia shows considerable fluctuation. Nevertheless, prevalence increases over time and with increasing age. Men who once had frequency-volume chart-nocturnal voiding frequency less than International Prostate Symptom Score-nocturnal voiding frequency are more likely to have this again. Therefore, frequency-volume charts as well as the International Prostate Symptom Score should be used when evaluating nocturia.


The Journal of Urology | 2014

Determinants of nocturia: the Krimpen study.

Boris van Doorn; Esther T. Kok; Marco H. Blanker; Paul Westers; J.L.H. Ruud Bosch

PURPOSE Many conditions and characteristics are cross-sectionally associated with nocturia. However, to our knowledge longitudinal associations of frequency-volume chart based nocturia have not yet been studied. We identify (modifiable) determinants of nocturia in older men in a longitudinal setting. MATERIALS AND METHODS A longitudinal, community based study was conducted among 1,688 men age 50 to 78 years in Krimpen aan den IJssel, The Netherlands with planned followup rounds at 2, 4 and 6 years. Men without a history of radical prostatectomy, transurethral surgery, or bladder or prostate cancer were included in the study. Data were obtained using frequency-volume charts, from which the nocturnal voiding frequency, maximum voided volume and (nocturnal) urine production were determined. Nocturia was defined as a nocturnal voiding frequency of 2 or more episodes. Polyuria was defined as greater than 2,800 ml voided per 24 hours. For nocturnal polyuria we used the 2 definitions of 1) greater than 33% of 24-hour voided volume and 2) nocturnal urine production of greater than 90 ml per hour. Conditions and characteristics were determined via medical examinations and questionnaires. A generalized linear mixed effect model was used to determine factors longitudinally associated with nocturia. RESULTS Age (50 to 55 years vs greater than 60 years), maximum voided volume (greater than 300 ml vs less than 300 ml), 24-hour polyuria, nocturnal polyuria (both definitions) and lower urinary tract symptoms were all longitudinally associated with an increased prevalence of nocturia in older men. CONCLUSIONS A smaller maximum voided volume, lower urinary tract symptoms, 24-hour polyuria and nocturnal polyuria are significant and potentially modifiable determinants of nocturia. The finding that both definitions for nocturnal polyuria are independent significant determinants may indicate a 2-step etiologic process for nocturnal polyuria.


The Journal of Pediatrics | 2014

Developmental Trajectories of Mobility and Self-Care Capabilities in Young Children with Cerebral Palsy

Marjolijn Ketelaar; Jan Willem Gorter; Paul Westers; Steven Hanna; Marjolein Verhoef

OBJECTIVE To describe development of mobility and self-care capabilities in young children (aged 1-4 years) with cerebral palsy, and to examine whether the development of mobility and self-care capabilities differs by cerebral palsy severity in terms of 5 distinct Gross Motor Function Classification System (GMFCS) levels. STUDY DESIGN This prospective longitudinal cohort study included 100 children with cerebral palsy (aged 1.5 or 2.5 years at baseline) and their parents. Mobility and self-care capabilities were assessed by the Pediatric Evaluation of Disability Inventory during yearly assessments from inclusion up to age 4.5 years. Longitudinal data for 92 children were available for analysis. Repeated-measures analyses with random coefficient analysis were performed using linear mixed models. RESULTS Despite large variations among individuals in the development of mobility and self-care capabilities in young children with cerebral palsy, distinct developmental trajectories were found for children in different GMFCS levels. The estimated change per month differed significantly by GMFCS level for both outcomes. CONCLUSIONS This longitudinal study provides an evidence base for prognosis in daily mobility and self-care skills in young children with cerebral palsy. The developmental trajectories for GMFCS levels can be helpful in communication between professionals and also in discussions of expectations and goal setting with families regarding mobility and self-care in the daily life of young children with cerebral palsy in neonatal follow-up and pediatric practice.


Asaio Journal | 2014

Noninvasive arterial blood pressure waveforms in patients with continuous-flow left ventricular assist devices.

Jerson R. Martina; Berend E. Westerhof; Nicolaas de Jonge; Jeroen van Goudoever; Paul Westers; Steven A. J. Chamuleau; Diederik van Dijk; Ben F.M. Rodermans; Bas A.J.M. de Mol; Jaap R. Lahpor

Arterial blood pressure and echocardiography may provide useful physiological information regarding cardiac support in patients with continuous-flow left ventricular assist devices (cf-LVADs). We investigated the accuracy and characteristics of noninvasive blood pressure during cf-LVAD support. Noninvasive arterial pressure waveforms were recorded with Nexfin (BMEYE, Amsterdam, The Netherlands). First, these measurements were validated simultaneously with invasive arterial pressures in 29 intensive care unit patients. Next, the association between blood pressure responses and measures derived by echocardiography, including left ventricular end-diastolic dimensions (LVEDDs), left ventricular end-systolic dimensions (LVESDs), and left ventricular shortening fraction (LVSF) were determined during pump speed change procedures in 30 outpatients. Noninvasive arterial blood pressure waveforms by the Nexfin monitor slightly underestimated invasive measures during cf-LVAD support. Differences between noninvasive and invasive measures (mean ± SD) of systolic, diastolic, mean, and pulse pressures were −7.6 ± 5.8, −7.0 ± 5.2, −6.9 ± 5.1, and −0.6 ± 4.5 mm Hg, respectively (all <10%). These blood pressure responses did not correlate with LVEDD, LVESD, or LVSF, while LVSF correlated weakly with both pulse pressure (r = 0.24; p = 0.005) and (dPart/dt)max (r = 0.25; p = 0.004). The dicrotic notch in the pressure waveform was a better predictor of aortic valve opening (area under the curve [AUC] = 0.87) than pulse pressure (AUC = 0.64) and (dPart/dt)max (AUC = 0.61). Patients with partial support rather than full support at 9,000 rpm had a significant change in systolic pressure, pulse pressure, and (dPart/dt)max during ramp studies, while echocardiographic measures did not change. Blood pressure measurements by Nexfin were reliable and may thereby act as a compliment to the assessment of the cf-LVAD patient.


European Radiology | 2011

Multidetector CT imaging of mechanical prosthetic heart valves : quantification of artifacts with a pulsatile in-vitro model

Petr Symersky; Ricardo P. J. Budde; Paul Westers; Bas A. J. M. de Mol; Mathias Prokop

ObjectivesMultidetector computed tomography (MDCT) can detect the cause of prosthetic heart valve (PHV) dysfunction but is hampered by valve-induced artifacts. We quantified artifacts of four PHV using a pulsatile in-vitro model and assessed the relation to leaflet motion and valve design.MethodsA Medtronic Hall tilting disc (MH), and Carbomedics (CM), St Jude (SJM), and ON-X bileaflet valves underwent CT in an in-vitro model using retrospective gating with a 64 detector CT system in stationary and pulsatile conditions. Artifacts and radiopaque component volumes were quantified with thresholds based on surrounding structures and valvular components.ResultsHypodense artifacts volumes (mm3) were 1,029 ± 147, 535 ± 53, 371 ± 16, and 366 ± 18 for the SJM, MH, CM and ON-X valves (p < 0.001 except for the latter two valves p = 0.43). Hyperdense artifact volumes were 3,546 ± 141, 2,387 ± 103, 2,003 ± 102, and 3,033 ± 31 for the SJM, MH, CM and ON-X valve, respectively (all differences p < 0.001). Leaflet motion affected hypodense (F = 41.5, p < 0.001) and hyperdense artifacts (F = 53.7, p < 0.001). Closed and moving leaflets were associated with the least and the most artifacts respectively (p < 0.001, both artifact types).ConclusionBoth valve design and leaflet motion affect PHV-induced artifacts. Best imaging results may be expected for the CM valve during phases in which the leaflets are closed.

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Ruud Bosch

University of California

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Mathias Prokop

Radboud University Nijmegen

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