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D S Postma

Publications and source records attributed to D S Postma.

At least 73 records · Page 4Linked to original sources
PubMed2002

Clinical evaluation of the effect of anti-allergic mattress covers in patients with moderate to severe asthma and house dust mite allergy: a randomised double blind placebo controlled study.

BACKGROUND: The use of anti-allergic mattress covers in patients with asthma can result in a large reduction in the level of house dust mite allergen in dust samples. Apart from a reduction in histamine induced bronchial hyperresponsiveness, there are few data on the effect of mattress covers on clinical efficacy and quality of life in patients with moderate to severe asthma. METHODS: Thirty patients with asthma and house dust mite allergy were studied in a randomised, double blind, placebo controlled study. Before and after using anti-allergic covers for 1 year, dust was collected from the mattresses to determine concentrations of Dermatophagoides pteronyssinus (Der p 1), and bronchial hyperresponsiveness and quality of life were measured. The patients scored their symptoms (lungs and nose), morning and evening peak flow values, and rescue medication for 14 days before and after the intervention period. RESULTS: There was a significant reduction in the concentration of Der p 1 in the dust collected from the mattresses in the actively treated group after 1 year compared with before treatment; no change was found in the placebo group. In both the actively treated and placebo groups there was no significant improvement in PC(20) histamine. Quality of life improved similarly in both groups. The symptom score of the lower airways did not significantly change in either group. A significant decrease in nasal symptom score was seen in the actively treated group compared with before treatment, but there was no significant difference between the groups. No changes in morning and evening peak flow values, peak flow variability, nor in the use of rescue medication were found in either group. CONCLUSION: The use of anti-allergic mattress covers results in significant reductions in Der p 1 concentrations in carpet-free bedrooms. However, in patients with moderate to severe asthma, airways hyperresponsiveness and clinical parameters are not affected by this effective allergen avoidance.

Adolescent↗
PubMed2002

Bone mineral density in patients with chronic obstructive pulmonary disease treated with budesonide Turbuhaler.

There is a need for studying the effects of long-term inhaled corticosteroid therapy on bone mineral density (BMD) and vertebral fracture rates in patients with mild chronic obstructive pulmonary disease (COPD). Patients (n=912, mean age 52 yrs) with mild COPD (mean forced expiratory volume in one second (FEV1) 77% of predicted; mean FEV1/slow vital capacity ratio 62%) were randomized to receive budesonide 400 microg, or placebo twice daily via Turbuhaler. BMD was measured at the L2-L4 vertebrae and the femoral neck, trochanter and Ward's triangle by dual-energy X-ray absorptiometry at baseline and after 6, 12, 24 and 36 months (n=161). Radiographs of the thoracic and lumbar spine were obtained at the beginning and end of treatment (n=653). Previous fractures were present at baseline in 43 budesonide-treated patients (13.4%) and 38 placebo-treated patients (11.5%). New fractures occurred in five budesonide-treated patients, compared with three in the placebo group (p=0.50). There were no significant changes in BMD at any site in budesonide-treated patients, compared with the placebo group, during the course of the study. Budesonide treatment was associated with a slight but statistically significant decrease in the area under the concentration-time curve for serum osteocalcin. In the present study, involving a large group of patients with chronic obstructive pulmonary disease, long-term treatment with budesonide 800 microg x day(-1) via Turbuhaler had no clinically significant effects on bone mineral density or fracture rates.

Administration, Inhalation↗
PubMed2001

One-year treatment with different dosing schedules of fluticasone propionate in childhood asthma. Effects on hyperresponsiveness, lung function, and height.

Dose-dependent effects of inhaled corticosteroids have been described. Although it has been advised to start treatment with inhaled corticosteroids with a high dose tapering off subsequently (stepdown approach), no clinical studies have assessed this strategy. We compared two different dosage schedules of inhaled fluticasone propionate (FP) in chronic persistent childhood asthma with respect to efficacy (airways hyperresponsiveness [PD(20)], lung function, exhaled nitric oxide [eNO]) and safety (height). During this double-blind study, children with asthma (aged 6-10 yr) were randomized to receive either FP 200 microg/d (constant dose approach) or to start with 1000 microg/d with two monthly reductions to 500, 200, and 100 microg/d (stepdown approach). PD(20) improved in both approaches during treatment with FP, with a significantly better PD(20) after 2 mo of 1000 microg/d followed by 500 microg/d in the stepdown approach versus 200 microg/d in the constant dose approach. No significant differences in PD(20) or other efficacy parameters were found after 1 yr. Changes in standing height were similar in both treatment approaches. This study showed no superior clinical effect of a stepdown approach compared with a constant dose strategy of FP for 1 yr in children with chronic persistent asthma.

Administration, Inhalation↗
PubMed2001

Corticosteroid-induced improvement in the PC20 of adenosine monophosphate is more closely associated with reduction in airway inflammation than improvement in the PC20 of methacholine.

It has been suggested in cross-sectional studies that provocation with adenosine 5'-monophosphate (AMP) more closely reflects the inflammatory process in asthma than does provocation with methacholine or histamine. We investigated whether the steroid-induced improvement in the provocative concentration of AMP producing a 20% decline in FEV1 (PC20 AMP) is more closely associated with the concomitant reduction in airway inflammation than is the improvement in PC20 methacholine. In 120 asthmatic patients, we measured PC20 methacholine and PC20 AMP as well as sputum induction and nitric oxide (NO) in exhaled air before and after 2 weeks of treatment with corticosteroids. Improvement in PC20 AMP was solely related to reduction in airway inflammation (i.e., change in the number of sputum eosinophils, lymphocytes, epithelial cells, and concentration of NO in exhaled air). In contrast, improvement in PC20 methacholine was related to both reduction in airway inflammation (i.e., change in the number of sputum eosinophils and lymphocytes) and increase in FEV1 %predicted. The total explained variance of the improvement in bronchial hyperresponsiveness was greater for AMP than for methacholine (36% versus 22%, respectively). We conclude that PC20 AMP is more sensitive to changes in acute airway inflammation than is PC20 methacholine, further reinforcing the notion that PC20 AMP can be a useful tool for monitoring the effects of antiinflammatory therapy.

Adenosine Monophosphate↗
PubMed2001

Long-term outcome of lung transplantation is predicted by the number of HLA-DR mismatches.

BACKGROUND: The importance of HLA mismatch in determining long-term outcome in lung transplantation remains largely uncertain. METHODS: A retrospective analysis of 102 consecutive primary lung transplants was performed to identify risk factors for poor long-term outcome after lung transplantation defined as graft survival and bronchiolitis obliterans syndrome (BOS) stage I and II. Variables included were patient characteristics (age, sex, prior diagnosis), the number of HLA mismatches between donor and recipient, cold ischemic time, cytomegalovirus serologic concordance, number of acute rejections, and time to first rejection. Variables carrying significance in a univariate analysis were subjected to a proportional hazard regression analysis. RESULTS: In the multivariate analysis, an increased number of acute rejections correlated positively with decreased graft survival (risk ratio [RR] = 1.25; 95% confidence interval [CI], 1.05-1.5; P = 0.011), development of BOS stage I (RR = 1.36/episode; 95% CI, 1.16-1.58;P < 0.001), and BOS stage II (RR = 1.42/episode; 95% CI, 1.2-1.67; P < 0.001). An increased time to rejection correlated positively with reduced graft survival (RR = 1.03/day; 95% CI, 1.01-1.06; P = 0.02), and BOS stage I and II (both RR = 1.04/day; 95% CI, 1.01-1.07; P < 0.005). Compared with 2 HLA-DR mismatches, 0 or 1 mismatch was associated with improved graft survival (RR = 0.43; 95% CI, 0.19-0.98; P = 0.045) and protected against development of BOS stage I (RR = 0.47; 95% CI, 0.23-0.98; P = 0.044) and BOS stage II (RR = 0.35; 95% CI, 0.15-0.83; P = 0.017). CONCLUSIONS: HLA-DR mismatching appears to be a risk factor for the development of BOS and graft loss. Improved outcome after lung transplantation might be achieved with prospective matching for HLA-DR. Alternatively, the amount and type of immunosuppressive drugs may be guided by the degree of HLA-DR (mis)matching.

Adolescent↗
PubMed2001

Comparison of formoterol and terbutaline for as-needed treatment of asthma: a randomised trial.

BACKGROUND: Asthma guidelines recommend that long-acting inhaled beta-agonists should be used as maintenance therapy for patients with asthma inadequately controlled on an inhaled corticosteroid. We studied the safety and efficacy of the long-acting beta-agonist formoterol compared with terbutaline, each taken as needed, in patients with moderate to severe asthma. METHODS: Patients were taking an inhaled corticosteroid (mean dose 870 microg daily) and had a forced expiratory volume in 1 s (FEV1) of at least 50% predicted (mean 74%). Those requiring an inhaled beta-agonist three to eight times a day during the study run-in period (362 of 621 who started) were randomly assigned formoterol 4.5 microg or terbutaline 0.5 mg as needed by Turbuhaler in daily doses up to 54 microg and 6 mg, respectively, for 12 weeks in a double-blind, parallel-group study. Analyses were by intention to treat. FINDINGS: The 362 randomised patients (157 men, 205 women) had a mean age of 47 years. Patients taking formoterol had a longer time to their first severe asthma exacerbation (relative-risk ratio 0.55 [95% CI 0.34-0.89]), took fewer inhalations of study drug, and had larger increases in FEV1 (5%) and morning and evening peak expiratory flow (mean difference in increase 11 L/min and 8 L/min) than those taking terbutaline. No safety issues were identified. INTERPRETATION: When taken as needed, formoterol 4.5 microg provided better asthma control than terbutaline 0.5 mg in patients requiring moderate doses of relief medication despite inhaled corticosteroid treatment. Safety studies should be extended to a wider population of patients with asthma.

Administration, Inhalation↗
PubMed2001

Apocynin and 1400 W prevents airway hyperresponsiveness during allergic reactions in mice.

1. The contribution of reactive nitrogen species to the development of airway hyperresponsiveness in a mouse model of allergic inflammation was investigated by the use of selective inhibitors of nitric oxide and superoxide formation. 2. Sensitized mice, repeatedly challenged with ovalbumin showed a significant (P<0.001, n=9) increase in airway responsiveness measured using whole body plethysmography. This hyperresponsiveness was accompanied by an influx of eosinophils into the airway lumen and increased levels of ovalbumin-specific serum IgE. 3. Treatment of mice with the iNOS inhibitor 1400 W or the NADPH-oxidase inhibitor apocynin did not significantly alter cellular influx into the airway lumen nor serum ovalbumin specific IgE. In contrast, apocynin as well as 1400 W inhibited ovalbumin-induced airway hyperresponsiveness (P<0.001 and P<0.05 respectively, n=9). Furthermore, the airways of allergen challenged animals showed clear 3-nitrotyrosine staining, which was mainly located in eosinophils. Remarkably, treatment with apocynin or 1400 W did not alter 3-nitrotyrosine staining. 4. These data suggest that the development of airway hyperresponsiveness during the airway inflammation upon ovalbumin challenge is dependent on the release of both superoxide and nitric oxide and is therefore likely to be dependent on reactive nitrogen species. This mechanism, however, is not reflected by 3-nitrotyrosine formation in the airways.

Acetophenones↗
PubMed2001

The NK-2 receptor antagonist SR 48968C does not improve adenosine hyperresponsiveness and airway obstruction in allergic asthma.

When stimulated, excitatory nonadrenergic noncholinergic (e-NANC) nerves locally release tachykinins like Neurokinin (NK) A and Substance P, causing neurogenic inflammation and airway obstruction via activation of specific NK-1 and NK-2 receptors. The recently developed nonpeptide NK-2 receptor antagonist SR 48968C has a high affinity for the NK-2 receptor, and is a strong and selective antagonist of NK-2 receptor mediated airway obstruction. In a placebo-controlled cross-over study, we investigated the effect of SR 48968C, administrated orally once-daily in a dosage of 100 mg during 9 days, on airway responsiveness to adenosine 5'-monophosphate (AMP) in 12 allergic asthmatic patients. Furthermore, we assessed its effect on airway obstruction, by measuring FEV1 on the first and last day of each treatment period and by peak flow registration at home throughout the study period. SR 48968C had no significant effect on PC20AMP or on FEV1 measured on day 1 and 9, and morning and evening peakflow measured at home on day 2-8. Thus, although SR 48968C was administrated in a dosage that might cause a demonstrable blocking effect on airway NK-2 receptors in asthma, it did not have a significant bronchodilatory or bronchoprotective effect against adenosine hyperresponsiveness in this study. Further studies are needed to assess the value of SR 48968C and other NK receptor antagonists in the treatment of asthma

Adenosine Monophosphate↗
PubMed2001

Adding formoterol to budesonide in moderate asthma--health economic results from the FACET study.

The FACET (Formoterol and Corticosteroid Establishing Therapy) study established that there is a clear clinical benefit in adding formoterol to budesonide therapy in patients who have persistent symptoms of asthma despite treatment with low to moderate doses of an inhaled corticosteroid. We combined the clinical results from the FACET study with an expert survey on average resource use in connection with mild and severe asthma exacerbations in the U.K., Sweden and Spain. The primary objective of this study was to assess the health economics of adding the inhaled long-acting beta2-agonist formoterol to the inhaled corticosteroid budesonide in the treatment of asthma. The extra costs of adding the inhaled beta2-agonist formoterol to the corticosteroid budesonide in asthmatic patients in Sweden were offset by savings from reduced use of resources for exacerbations. For Spain the picture was mixed. Adding formoterol to low dose budesonide generated savings, whereas for moderate doses of budesonide about 75% of the extra formoterol costs could be recouped. In the U.K., other savings offset about half of the extra cost of formoterol. All cost-effectiveness ratios are within accepted cost-effectiveness ranges reported from previous studies. If productivity losses were included, there were net savings in all three countries, ranging from Euro 267-1183 per patient per year. In conclusion, adding the inhaled, long-acting beta2-agonist formoterol to low-moderate doses of the inhaled corticosteroid budesonide generated significant gains in all outcome measures with partial or complete offset of costs. Adding formoterol to budesonide can thus be considered to be cost-effective.

Acute Disease↗
PubMed2001

Resistance of activated human Th2 cells to NO-induced apoptosis is mediated by gamma-glutamyltranspeptidase.

Activation-induced death of inflammatory cells (AICD) has an important function in immune maintenance. Type 1 Th cells are known to be more susceptible to AICD than Th2 cells. In the current study we examined whether NO-induced apoptosis also preferentially eliminates Th1 cells over Th2 cells. Naive human Th lymphocytes (CD4(+)CD45RO(-)) were activated in vitro for 1 week in the presence of IL-12 plus anti-IL-4 or IL-4 plus anti-IL-12 to generate Th1- and Th2-polarized cultures respectively. Cultures were exposed to the NO donors Spermine-nonoate (Sper) and DPTA-nonoate to study NO-induced apoptosis. We found that NO preferentially induced apoptosis in Th1-polarized cells as demonstrated by Annexin staining in the presence of 10 microM Sper (70 +/- 16 versus 23 +/- 4.4% in Th2 cells P: < 0.01) and by DioC6 staining (38 +/- 10 versus 11 +/- 5% in Th2 cells, P: < 0.01). The mechanism of NO-induced apoptosis in Th1/Th2-polarized cells was distinct from AICD and Fas-induced apoptosis. Differential sensitivity between Th1- and Th2-polarized cultures originated at the level of intracellular glutathione (GSH) metabolism. GSH levels were higher in Th2 cells (1.6 +/- 0.2-fold Th1, P: < 0.01). High intracellular GSH in Th2-polarized cells did not account for reduced susceptibility to NO per se, since the inhibition of gamma-glutamyltrans-peptidase (gamma-GT), which is involved in GSH import, sensitized Th2 cells to NO-induced apoptosis without GSH depletion. Therefore, higher activity of gamma-GT in Th2 cells (2.1 +/- 0.4-fold Th1, P: < 0.001) specifically protects Th2 cells against NO-induced apoptosis. Preferential NO-induced elimination of human Th1 cells at sites of inflammation may thus select Th2 cells and contribute to immune deviation.

Apoptosis↗
PubMed2001

Repeatability of bronchial hyperresponsiveness to adenosine-5'-monophosphate (AMP) by a short dosimeter protocol.

BACKGROUND: To study bronchial responsiveness to adenosine 5'-monophosphate (AMP) in population surveys, repeatability of a rapid dosimetric method with quadrupling doses was evaluated. METHODS: Volunteers with symptoms of airway respiratory allergy or asthma were invited for AMP challenges on two occasions. After each dose the fall in forced expiratory volume in one second (FEV(1)) compared with the post-saline value was determined. The cumulative doses of AMP needed to cause a fall in FEV(1) of 20% (PD(20)), 15% (PD(15)), and 10% (PD(10)) were calculated. Agreement was evaluated by means of kappa values. After excluding systematic differences in PD values on two occasions (t test), repeatability of a single estimation of the chosen PD values was calculated and expressed in doubling doses (DD). RESULTS: In 28 of 76 subjects a PD(20) was estimated on the two visits, in 29 subjects a PD(15) was estimated, and in 32 a PD(10) was obtained. Kappa values for a positive threshold were 0.89 for a cut off level for a 20% fall in FEV(1), 0.78 for a 15% fall in FEV(1), and 0.76 for a fall in FEV(1) of 10%. The PD values did not differ between the two visits and 95% repeatability of a single estimation was +/-1.7 DD for PD(20), +/-2.2 DD for PD(15), and +/-2.4 DD for PD(10). The quadrupling dose method reduced time by 40% in non-hyperresponsive subjects and no adverse effects were observed. CONCLUSION: The short dosimeter protocol with quadrupling doses for AMP challenges is a rapid, reproducible tool for estimating bronchial responsiveness in population surveys.

Adenosine Monophosphate↗
PubMed2001

Association of a promoter polymorphism of the CD14 gene and atopy.

Atopy is generally considered to be caused by interaction of genetic and environmental factors. Recently, an association of a C-to-T transition in the promoter region of the CD14 gene on chromosome 5q31.1 and atopic phenotypes was reported in a population study of school children in the United States. The aim of the present study was to investigate the association of the C allele of the CD14/-159 with phenotypes of atopy and asthma in an adult Dutch population in which linkage of total serum IgE and bronchial hyperresponsiveness to chromosome 5q31-33 is present. We studied 159 probands with asthma and 158 spouses as controls. Phenotypes for asthma (e.g., bronchial hyperresponsiveness, physician's diagnosis) and for atopy (e.g., total serum IgE level, intracutaneous skin test, allergic rhinitis) were studied. In this population, homozygotes for the C allele had a higher number of positive skin tests and higher total serum IgE levels (in skin test-positive individuals) and subsequently, more self-reported allergic symptoms including rhinitis and hay fever, compared with subjects with CT and TT alleles. We conclude that the -159 C-to-T promoter polymorphism in the CD14 gene may result in expression of a more severe allergic phenotype.

Adult↗
PubMed2001

PC(20) adenosine 5'-monophosphate is more closely associated with airway inflammation in asthma than PC(20) methacholine.

Inhalation of a direct stimulus such as histamine or methacholine is generally used to measure bronchial hyperresponsiveness (BHR). Provocation with adenosine 5'-monophosphate (AMP), an indirect airway challenge, has been suggested to be a better marker of airway inflammation than direct challenges. However, so far little information on this subject is available. The aim of our study was to assess whether the concentration of AMP causing the FEV(1) to drop by 20% (PC(20)) is more closely associated with inflammatory parameters in asthma than PC(20) methacholine. In 120 patients with atopic asthma (median FEV(1) 81% predicted [pred], median age 27 yr), PC(20) methacholine and PC(20) AMP as well as sputum induction, blood sampling, and measurement of nitric oxide in exhaled air were performed. PC(20) methacholine was predominantly predicted by FEV(1) %pred (explained variance [ev] = 18%) with the percentage of peripheral blood monocytes being a weak additional independent predictor (total ev = 23%). By contrast, PC(20) AMP was predominantly predicted by the percentage of eosinophils in sputum (ev = 25%), while FEV(1) %pred was only an additional independent predictor (total ev = 36%). PC(20) AMP reflects more closely the extent of airway inflammation due to asthma than PC(20) methacholine.

Adenosine Monophosphate↗
PubMed2001

Identification and association of polymorphisms in the interleukin-13 gene with asthma and atopy in a Dutch population.

Asthma and atopy are related conditions that may share similar genetic susceptibility. Linkage studies have identified a region on chromosome 5q that contains biologic candidates for both asthma and atopy phenotypes, including several proinflammatory cytokines. Interleukin (IL)-13, one of the candidate genes in the region, is directly involved in the regulation of immunoglobulin E and has been associated with both asthma and atopy. We sought to identify new polymorphisms in the IL-13 gene, and evaluated the involvement of a subset of these variants in asthma and atopy in a case-control study using probands and spouses from a Dutch asthma family study. IL-13 was sequenced in 20 probands and 20 unaffected spouses, and 10 polymorphisms were identified, four novel and six previously reported. Three single nucleotide (nt) polymorphisms (SNPs) were detected in the 5'-promoter region, two in intron 1, and five in exon 4. Only one of the exon 4 SNPs resulted in an amino-acid change (Arg130Gln). We analyzed three SNPs in IL-13 in an extended group of 184 probands and their spouses: one in the promoter region (-1111), the Arg130Gln (nt position 4257), and a 3' untranslated region SNP (nt position 4738). The most significant associations were observed to asthma (P = 0.005), bronchial hyperresponsiveness (P = 0.003), and skin-test responsiveness (P = 0.03) with the -1111 promoter. These results provide evidence that variation in the IL-13 gene is involved in the pathogenesis of asthma and atopy. Further investigation is required to determine which specific alleles or combination of alleles contribute to these phenotypes, and the possible downstream effects of the resulting change in IL-13 levels or activity.

Adult↗