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Dive into the research topics where J.K. Sont is active.

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Featured researches published by J.K. Sont.


Thorax | 1996

Relationship between the inflammatory infiltrate in bronchial biopsy specimens and clinical severity of asthma in patients treated with inhaled steroids.

J.K. Sont; J. Han; J. M. van Krieken; C. E. Evertse; R. Hooijer; Luuk N.A. Willems; P. J. Sterk

BACKGROUND: Current guidelines on the management of asthma advocate the use of anti-inflammatory treatment in all but mild disease. They define disease control in terms of clinical criteria such as lung function and symptoms. However, the relationship between the clinical control of the disease and inflammation of the airways is not clear. A cross sectional study was therefore undertaken to investigate the relationship between airways inflammation and measures of clinical control and bronchial hyperresponsiveness in asthmatic patients treated with inhaled steroids. METHODS: Twenty six atopic adults (19-45 years) with mild to moderate asthma (baseline forced expiratory volume in one second (FEV1) > or = 50% predicted, concentration of histamine causing a 20% fall in FEV1 (PC20) 0.02-7.6 mg/ml) on regular treatment with inhaled steroids entered the study. Diary card recordings during the two weeks before a methacholine challenge test and bronchoscopic examination were used to determine peak flow variability, symptom scores, and use of beta 2 agonists. Biopsy specimens were taken by fibreoptic bronchoscopy from the carina of the right lower and middle lobes, and from the main carina. Immunohistochemical staining was performed on cryostat sections with monoclonal antibodies against: eosinophil cationic protein (EG1, EG2), mast cell tryptase (AA1), CD45, CD22, CD3, CD4, CD8, CD25, and CD45RO. The number of positively stained cells in the lamina propria was counted twice by using an interactive display system. RESULTS: There were no differences in cell numbers between the three sites from which biopsy specimens were taken. The PC20 for methacholine was inversely related to the average number of total leucocytes, EG1+, and EG2+ cells, mast cells, CD8+, and CD45RO+ cells in the lamina propria. These relationships were similar for each of the biopsy sites. Symptom scores, beta 2 agonist usage, FEV1, and peak flow variability were not related to any of the cell counts. CONCLUSIONS: Infiltration of inflammatory cells in the lamina propria of the airways seems to persist in asthmatic outpatients despite regular treatment with inhaled steroids. The number of infiltrating leucocytes such as mast cells, (activated) eosinophils, CD8+, and CD45RO+ cells in bronchial biopsy specimens from these patients appears to be reflected by airway hyperresponsiveness to methacholine, but not by symptoms or lung function. These findings may have implications for the adjustment of anti-inflammatory treatment of patients with asthma.


European Respiratory Journal | 1996

Repeatability of cellular and soluble markers of inflammation in induced sputum from patients with asthma

J.C.C.M. in 't Veen; H. W. F. M. De Gouw; Hermelijn H. Smits; J.K. Sont; Pieter S. Hiemstra; P. J. Sterk; E.H. Bel

Sputum induced by inhalation of nebulized hypertonic saline is increasingly used to monitor airways inflammation in asthma. The aim of this study was to assess the repeatability of measuring cellular and soluble markers of inflammation in whole sputum samples as obtained by sputum induction in patients both with mild and moderate-to-severe asthma. Twelve patients with mild, atopic asthma without inhaled steroid treatment and nine patients with moderate-to-severe, atopic asthma treated with inhaled steroids were studied on two separate days at least 2 days apart. Whole sputum samples, induced by inhalation of hypertonic (4.5%) saline, were homogenized, and analysed for differential cell counts and for concentrations of albumin, fibrinogen, interleukin-8 (IL-8), and eosinophil cationic protein (ECP). Repeatability was expressed as intraclass correlation coefficient (Ri), and as coefficient of repeatability (CR) in percentage cells or in doubling concentration. Samples from two patients with mild asthma contained more than 80% squamous cells and were excluded from analysis. The repeatability for cell differential counts in both groups combined was: for neutrophils, Ri = 0.57 and CR = 31.0; for eosinophils, Ri = 0.85 and CR = 12.4; and for lymphocytes, Ri = 0.76 and CR = 6.9. The repeatability of the fluid phase measurements was: for albumin, Ri = 0.71 and CR = 3.2; for fibrinogen, Ri = 0.88 and CR = 2.8; for IL-8, Ri = 0.66 and CR = 2.2; and for ECP, Ri = 0.82 and CR = 1.1. We conclude that the repeatability of cellular and soluble markers of inflammation in induced sputum from patients with mild and moderate-to-severe asthma is satisfactory. Hence, induced sputum, processed by using the whole expectorated sample, seems to be a valuable method to monitor airway inflammation in asthma.


Clinical & Experimental Allergy | 1997

Comparison of inflammatory cell counts in asthma: induced sputum vs bronchoalveolar lavage and bronchial biopsies

D. C. Grootendorst; J.K. Sont; Luuk N.A. Willems; Johanna Kluin-Nelemans; J.H.J.M. van Krieken; M. Veselic-Charvat; P. J. Sterk

Background Induced sputum potentially allows monitoring of airway inflammation in patients with asthma in a non‐invasive way. However, the relationship between the cellular content in sputum and airway tissue has not been fully clarified.


Brain | 2011

A 12-year follow-up in sporadic inclusion body myositis: an end stage with major disabilities

Fieke M. Cox; Maarten J. Titulaer; J.K. Sont; Axel R. Wintzen; Jan J. Verschuuren; Umesh A. Badrising

Sporadic inclusion body myositis is considered to be a slowly progressive myopathy. Long-term follow-up data are, however, not yet available. Follow-up data are important with a view to informing patients about their prognosis and selecting appropriate outcome measures for clinical trials. We performed a follow-up study of 64 patients with sporadic inclusion body myositis who participated in a national epidemiological study in the Netherlands. Case histories were recorded, and manual and quantitative muscle tests as well as laboratory tests were performed at baseline and 12 years (median) after the first out-patient visit. Date and cause of death were recorded for all deceased patients. Forty-six patients died during the follow-up period, two patients chose not to participate and one patient was lost to follow-up. The remaining 15 surviving patients had a mean disease duration of 20 years and were clinically evaluated at the second time point. The mean decline in strength was 3.5 and 5.4% per year according to the manual muscle testing and quantitative muscle testing, respectively. This decline was most pronounced in the lower legs, which were also the weakest extremities. Life expectancy was normal at 81 years, but activities of daily life were clearly restricted. At follow-up, all patients were found to be using a wheelchair, seven of them (47%) being completely wheelchair-bound. Disorders of the respiratory system were the most common cause of death. In three patients, euthanasia was requested and in another three, continuous deep sedation was applied. The fact that end-of-life care interventions were used in six patients (13%) reflects the severe disability and loss of quality of life at the end stage of this disease. Sporadic inclusion body myositis is a chronic progressive disorder, leading to major disabilities at the end stage of the disease due to extensive muscle weakness.


European Respiratory Journal | 2008

Exhaled nitric oxide predicts lung function decline in difficult-to-treat asthma.

I.H. van Veen; A. ten Brinke; Peter J. Sterk; J.K. Sont; Stefanie A. Gauw; Klaus F. Rabe; E.H. Bel

A subset of patients with asthma is known to have progressive loss of lung function despite treatment with corticosteroids. The aim of the present study was to identify risk factors of decline in forced expiratory volume in one second (FEV1) in patients with difficult-to-treat asthma. In total, 136 nonsmoking patients with difficult-to-treat asthma were recruited between 1998 and 1999. Follow-up assessment was performed 5–6u2005yrs later in 98 patients. The predictive effect of clinical characteristics and inflammatory markers were analysed at baseline (asthma onset and duration, atopy, airway hyperresponsiveness, blood and sputum eosinophils, and the fraction of nitric oxide in exhaled air (FeNO)) on subsequent decline in post-bronchodilator FEV1. Patients with high FeNO (≥20u2005ppb) had an excess decline of 40.3 (95% confidence interval (CI) 7.3–73.2)u2005mL·yr−1 compared to patients with low FeNO. FeNO ≥20u2005ppb was associated with a relative risk of 1.9 (95% CI, 1.1–2.6) of having an accelerated (≥25u2005mL·yr−1) decline in FEV1. In patients with baseline FEV1 ≥80% of predicted, this relationship was even stronger: 90 versus 29% had accelerated decline in FEV1 (FeNO ≥20u2005ppb versus FeNO <20u2005ppb respectively; relative risk 3.1 (95% CI, 1.7–3.4). Exhaled nitric oxide is a predictor of accelerated decline in lung function in patients with difficult-to-treat asthma, particularly if forced expiratory volume in one second is still normal.


Journal of Clinical Oncology | 2011

Clinical Dutch-English Lambert-Eaton Myasthenic Syndrome (LEMS) Tumor Association Prediction Score Accurately Predicts Small-Cell Lung Cancer in the LEMS

Maarten J. Titulaer; Paul Maddison; J.K. Sont; Paul W. Wirtz; David Hilton-Jones; Rinse Klooster; Nick Willcox; Marko Potman; Peter A. E. Sillevis Smitt; Jan B. M. Kuks; Bart O. Roep; Angela Vincent; Silvère M. van der Maarel; J. Gert van Dijk; Bethan Lang; Jan J. Verschuuren

PURPOSEnApproximately one half of patients with Lambert-Eaton myasthenic syndrome (LEMS) have small-cell lung carcinomas (SCLC), aggressive tumors with poor prognosis. In view of its profound impact on therapy and survival, we developed and validated a score to identify the presence of SCLC early in the course of LEMS.nnnPATIENTS AND METHODSnWe derived a prediction score for SCLC in LEMS in a nationwide cohort of 107 Dutch patients, and validated it in a similar cohort of 112 British patients. A Dutch-English LEMS Tumor Association Prediction (DELTA-P) score was developed based on multivariate logistic regression.nnnRESULTSnAge at onset, smoking behavior, weight loss, Karnofsky performance status, bulbar involvement, male sexual impotence, and the presence of Sry-like high-mobility group box protein 1 serum antibodies were independent predictors for SCLC in LEMS. A DELTA-P score was derived allocating 1 point for the presence of each of the following items at or within 3 months from onset: age at onset ≥ 50 years, smoking at diagnosis, weight loss ≥ 5%, bulbar involvement, erectile dysfunction, and Karnofsky performance status lower than 70. The area under the curve of the receiver operating curve was 94.4% in the derivation cohort and 94.6% in the validation set. A DELTA-P score of 0 or 1 corresponded to a 0% to 2.6% chance of SCLC, whereas scores of 4, 5, and 6 corresponded to chances of SCLC of 93.5%, 96.6%, and 100%, respectively.nnnCONCLUSIONnThe simple clinical DELTA-P score discriminated patients with LEMS with and without SCLC with high accuracy early in the course of LEMS.


Respiratory Research | 2007

Smoking cessation and bronchial epithelial remodelling in COPD: a cross-sectional study

Therese S. Lapperre; J.K. Sont; Annemarie van Schadewijk; M. M. E. Gosman; Dirkje S. Postma; Ingeborg M. Bajema; Wim Timens; Thais Mauad; Pieter S. Hiemstra

BackgroundChronic Obstructive Pulmonary Disease (COPD) is associated with bronchial epithelial changes, including squamous cell metaplasia and goblet cell hyperplasia. These features are partially attributed to activation of the epidermal growth factor receptor (EGFR). Whereas smoking cessation reduces respiratory symptoms and lung function decline in COPD, inflammation persists. We determined epithelial proliferation and composition in bronchial biopsies from current and ex-smokers with COPD, and its relation to duration of smoking cessation.Methods114 COPD patients were studied cross-sectionally: 99 males/15 females, age 62 ± 8 years, median 42 pack-years, no corticosteroids, current (n = 72) or ex-smokers (n = 42, median cessation duration 3.5 years), postbronchodilator FEV1 63 ± 9% predicted. Squamous cell metaplasia (%), goblet cell (PAS/Alcian Blue+) area (%), proliferating (Ki-67+) cell numbers (/mm basement membrane), and EGFR expression (%) were measured in intact epithelium of bronchial biopsies.ResultsEx-smokers with COPD had significantly less epithelial squamous cell metaplasia, proliferating cell numbers, and a trend towards reduced goblet cell area than current smokers with COPD (p = 0.025, p = 0.001, p = 0.081, respectively), but no significant difference in EGFR expression. Epithelial features were not different between short-term quitters (<3.5 years) and current smokers. Long-term quitters (≥3.5 years) had less goblet cell area than both current smokers and short-term quitters (medians: 7.9% vs. 14.4%, p = 0.005; 7.9% vs. 13.5%, p = 0.008; respectively), and less proliferating cell numbers than current smokers (2.8% vs. 18.6%, p < 0.001).ConclusionEx-smokers with COPD had less bronchial epithelial remodelling than current smokers, which was only observed after long-term smoking cessation (>3.5 years).Trial registrationNCT00158847


Journal of Asthma | 2008

Illness Perceptions and COPD: An Emerging Field for COPD Patient Management

Ad A. Kaptein; Margreet Scharloo; Maarten J. Fischer; Lucia Snoei; Linda D. Cameron; J.K. Sont; Klaus F. Rabe; John Weinman

Objective. Patients with chronic obstructive pulmonary disease have perceptions of their illness and its management that determine their coping behaviors (e.g., adherence, self-management) and, consequently, their outcomes. This article reviews the empirical literature on illness perceptions in patients with COPD to provide clinicians with information regarding the potential utility of incorporating illness perceptions into clinical COPD care. Method. A literature search in PubMed identified 16 studies examining associations between illness perceptions and outcomes in patients with COPD. Results. Seven of the 16 papers were from US authors, followed by 3 each from the UK and The Netherlands, and one study each from Australia, Canada, and New Zealand. The first study was published in 1983, and the numbers of patients per study ranged fom 10 to 266. The illness perceptions were those delineated by two theoretical models (cognitive behavioral theory and the Common Sense Model), and they were assessed with open interviews and validated questionnaires. Outcomes were disability, quality of life, and psychological characteristics. The studies revealed clinically meaningful associations between illness perceptions and outcomes. Conclusion. Our review supports the incorporation of illness perceptions into clinical care for patients with COPD. The assessment of illness perceptions should be routine, similar to routine assessments of pulmonary function. Discussing and changing illness perceptions will improve COPD patients quality of life and reduce their levels of disability. COPD-specific assessments (“diagnosis”) of illness perceptions and COPD-specific intervention methods (“therapy”) that help change inadequate and maladaptive illness perceptions are research priorities.


BMJ | 2014

Effectiveness of integrated disease management for primary care chronic obstructive pulmonary disease patients: results of cluster randomised trial.

Annemarije Kruis; Melinde Boland; Willem J. J. Assendelft; Jacobijn Gussekloo; Apostolos Tsiachristas; Theo Stijnen; Coert Blom; J.K. Sont; Maureen P.H.M. Rutten-van Mölken; Niels H. Chavannes

Objective To investigate the long term effectiveness of integrated disease management delivered in primary care on quality of life in patients with chronic obstructive pulmonary disease (COPD) compared with usual care. Design 24 month, multicentre, pragmatic cluster randomised controlled trial Setting 40 general practices in the western part of the Netherlands Participants Patients with COPD according to GOLD (Global Initiative for COPD) criteria. Exclusion criteria were terminal illness, cognitive impairment, alcohol or drug misuse, and inability to fill in Dutch questionnaires. Practices were included if they were willing to create a multidisciplinary COPD team. Intervention General practitioners, practice nurses, and specialised physiotherapists in the intervention group received a two day training course on incorporating integrated disease management in practice, including early recognition of exacerbations and self management, smoking cessation, physiotherapeutic reactivation, optimal diagnosis, and drug adherence. Additionally, the course served as a network platform and collaborating healthcare providers designed an individual practice plan to integrate integrated disease management into daily practice. The control group continued usual care (based on international guidelines). Main outcome measures The primary outcome was difference in health status at 12 months, measured by the Clinical COPD Questionnaire (CCQ); quality of life, Medical Research Council dyspnoea, exacerbation related outcomes, self management, physical activity, and level of integrated care (PACIC) were also assessed as secondary outcomes. Results Of a total of 1086 patients from 40 clusters, 20 practices (554 patients) were randomly assigned to the intervention group and 20 clusters (532 patients) to the usual care group. No difference was seen between groups in the CCQ at 12 months (mean difference –0.01, 95% confidence interval –0.10 to 0.08; P=0.8). After 12 months, no differences were seen in secondary outcomes between groups, except for the PACIC domain “follow-up/coordination” (indicating improved integration of care) and proportion of physically active patients. Exacerbation rates as well as number of days in hospital did not differ between groups. After 24 months, no differences were seen in outcomes, except for the PACIC follow-up/coordination domain. Conclusion In this pragmatic study, an integrated disease management approach delivered in primary care showed no additional benefit compared with usual care, except improved level of integrated care and a self reported higher degree of daily activities. The contradictory findings to earlier positive studies could be explained by differences between interventions (provider versus patient targeted), selective reporting of positive trials, or little room for improvement in the already well developed Dutch healthcare system. Trial registration Netherlands Trial Register NTR2268.


European Respiratory Journal | 2002

Rhinovirus infection in nonasthmatic subjects: effects on intrapulmonary airways.

J. De Kluijver; K. Grünberg; J.K. Sont; M. Hoogeveen; W.A.A.M. van Schadewijk; E. P. A. De Klerk; Claire R. Dick; J.H.J.M. van Krieken; P. J. Sterk

The common cold is a highly prevalent, uncomplicated upper airway disease. However, rhinovirus (RV) infection can lead to exacerbation of asthma, with worsening in airway hyperresponsiveness and bronchial inflammation. The current authors questioned whether such involvement of the intrapulmonary airways is disease specific. Twelve nonatopic, healthy subjects (forced expiratory volume in one second (FEV1) >80% predicted, provocation concentration causing a 20% fall in FEV1 (PC20) >8u2005mg·mL−1) were experimentally infected with RV16. Next to PC20 and the maximal response to methacholine (MFEV1 and MV′40p), the numbers of mucosal inflammatory cells and epithelial intercellular adhesion molecule (ICAM)‐1 expression in bronchial biopsies were assessed before and 6 days after RV16 inoculation. RV16 infection induced a small but consistent increase in maximal airway narrowing, without a change in PC20. There was a significant increase in bronchial epithelial ICAM‐1 expression after RV16, whereas inflammatory cell counts did not change. Nevertheless, the change in the number of submucosal CD3+ cells was correlated with the change in MV′40p. In conclusion, rhinovirus infection in normal subjects induces a limited, but significant increase in maximal airway narrowing, which is associated with changes in bronchial T‐cell numbers. Together with the upregulation of bronchial epithelial intercellular adhesion molecule‐1, these findings indicate that, even in healthy subjects, rhinovirus infection affects the intrapulmonary airways.

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P. J. Sterk

University of Amsterdam

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Pieter S. Hiemstra

Leiden University Medical Center

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Willem J. J. Assendelft

Radboud University Nijmegen Medical Centre

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Luuk N.A. Willems

Leiden University Medical Center

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E.H. Bel

Leiden University Medical Center

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J. B. Snoeck-Stroband

Loyola University Medical Center

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