Biomedical subjects

Johan C de Jongste

Publications and source records attributed to Johan C de Jongste.

12 recordsLinked to original sources

PubMed2004

Preserved diffusion capacity in children with cystic fibrosis.

Early detection of progressive lung disease in cystic fibrosis (CF) may lead to better treatment and prognosis. Routine lung function indices may be relatively insensitive markers of peripheral airway obstruction and alveolar collapse. We hypothesized that the single-breath diffusion capacity of the lung for carbon monoxide (DLCO) would change before tests of airway function in patients with CF. We assessed lung function longitudinally in 53 children with CF during a mean period of 3.8 years to determine whether the diffusion capacity of the lung becomes abnormal before more conventional indices of lung function do. Within patients, DLCO was slightly elevated and remained stable, while forced expired volume in 1 sec (FEV1) and forced vital capacity (FVC) declined progressively (mean individual decline, -1.8% and -0.8% of predicted). Cross-sectionally, this decline was faster (mean group decline -3.8% and -2.8% of predicted), indicating an additional cohort effect. Normalized diffusion capacity at an early stage of CF is slightly elevated and is preserved in spite of progressive obstructive lung disease. This can be attributed to alterations in pulmonary and bronchial circulation due to loss of function and/or number of alveolar units. Diffusion capacity at rest does not appear to be a suitable early marker of progressive deterioration of CF lung disease.

Adolescent↗

PubMed2004

Determining factors of aerosol deposition for four pMDI-spacer combinations in an infant upper airway model.

The aim of this study was to measure and compare the influence of tidal volume (Vt) respiratory rate (RR) and pMDI/spacer combination on aerosol deposition of 4 pMDI/spacer combinations, which are used for infants. An anatomically correct upper airway model of a 9-month-old infant was connected to a breathing simulator. Sinusoidal breathing patterns were simulated with; duty cycle T(i)/T(tot) = 0.42, Vt: 25, 50, 75, 100, 150, 200 ml (RR: 30 breaths/min); and RR: 20, 30, 42, 60, 78 breaths/min (Vt: 100 mL). pMDI/Spacers tested were: budesonide 200 microg/Nebuchamber, fluticasone 125 microg/Babyhaler and both budesonide and fluticasone with Aerochamber. Plastic spacers were detergent coated to reduce electrostatic charge. Spacer-output and lung dose were measured by a filter positioned between spacer and facemask or between model and breathing simulator. Particle size distribution of lung dose was assessed with an impactor during simulated breathing. Spacer-output was significantly positively correlated with Vt for all pMDI/spacers (all R > 0.77, p < 0.001), but not correlated with RR. Lung doses initially increased from Vt = 25 to 50 mL (Nebuchamber, Aerochamber) or to 100 mL (Babyhaler) and then decreased, with increasing Vt and RR (R: -0.98 to -0.82, p < 0.001). Lung doses of fluticasone were 1.5-6-fold higher compared with budesonide, irrespective of spacer type (p < 0.001). MMAD decreased with increasing Vt and RR. Dose to the lungs of particles <2.1 microm was independent of Vt and RR. Lung dose decreases with increasing inspiratory flow (increasing Vt or RR) by increasing impaction of coarse particles in the upper airways. Deposition of particles <2.1 microm is relatively flow independent. When electrostatic charge of spacers is reduced, lung dose is pMDI dependent and spacer independent.

Aerosols↗

PubMed2003

Influenza vaccination in children with asthma: randomized double-blind placebo-controlled trial.

There is little evidence that influenza vaccination reduces asthma exacerbations. We determined whether influenza vaccination is more effective than placebo in 6-18-year-old children with asthma. We performed a randomized, double-blind, placebo-controlled trial. Parenteral vaccination with inactivated influenza vaccine or placebo took place approximately November 1, and children were followed until April 1 of the next year. Airway symptoms were reported in a diary. When symptom scores reached a predefined level, a pharyngeal swab was taken. Primary outcome was the number of asthma exacerbations associated with virologically proven influenza infection. Three hundred forty-nine children were assigned placebo, and 347 were assigned vaccine. Pharyngeal swabs positive for influenza were related to 42 asthma exacerbations, 24 in the vaccine group and 18 in the placebo group, a difference of 33% favoring placebo (31% after adjustment for confounders; 95% confidence interval, -34% to 161%). Influenza-related asthma exacerbations were of similar severity in both groups; they lasted 3.1 days shorter in the vaccine group (95% confidence interval, -6.2 to 0.002 days, p = 0.06). We conclude that influenza vaccination did not result in a significant reduction of the number, severity, or duration of asthma exacerbations caused by influenza. Additional studies are warranted to justify routine influenza vaccination of children with asthma.

Adolescent↗

PubMed2003

Interrupter resistance and wheezing phenotypes at 4 years of age.

It is difficult to distinguish young children with respiratory symptoms who will develop asthma from those with transient symptoms only. Measurement of interrupter resistance may help to identify children at high risk of asthma. The aim of this study is to compare interrupter resistance in 4-year-old children with different wheezing phenotypes. All children participated in the Prevention and Incidence of Asthma and Mite Allergy cohort, a prospective birth cohort of more than 4,000 children. At 4 years of age, data on interrupter resistance plus wheezing phenotype were available for 838 children. Mean interrupter resistance values (95% confidence interval) were 0.95 (0.93, 0.97), 0.95 (0.92, 0.98), 0.96 (0.87, 1.05), and 1.08 (1.02, 1.14) kPa.L(-1).second for never (n = 482), early transient (n = 236), late-onset (n = 22), and persistent (n = 98) wheezing phenotypes, respectively. Additional analyses were performed for children with atopic and nonatopic mothers separately. Both in children with atopic and nonatopic mothers, children with persistent wheeze had significantly higher interrupter resistance values than children with never and early wheeze. In conclusion, mean interrupter resistance values were higher in children with persistent wheeze as compared with children with never and early transient wheezing phenotypes.

Airway Resistance↗

PubMed2003

Birth order and sibship size as independent risk factors for asthma, allergy, and eczema.

This study was carried out to disentangle the independent relations of birth order and sibship size with the presence of asthma, allergy and eczema. In a retrospective study, 700 families in the Netherlands were selected with index children born in 1988-90. Data were extracted from reports of health examinations at the age of 6 years of these children and their siblings. Birth order, and not sibship size, appeared to be a strong risk factor for allergy (excluding eczema). Children with higher birth order had a lower risk of allergy compared with first-borns (adjusted odds ratios: 0.43, 0.26 and 0.05 for second-, third- and fourth- or higher borns, respectively; p < 0.0001). Allergy including eczema also had a significant relation with birth order (p = 0.01). For asthma there appeared no clear relation with birth order. For asthma a non-significant relationship with sibship size (adjusted for birth order) was found (p = 0.06): first-born children in small sibships were more at risk than those in larger sibships. For allergy and eczema no such trend was observed. In conclusion, birth order is inversely related to the risk of allergy, independent of the size of the sibship.

Asthma↗

PubMed2003

Exhaled nitric oxide in mylar balloons: influence of storage time, humidity and temperature.

BACKGROUND: Mylar balloons are used to collect exhaled air for analysis of fractional nitric oxide concentration (FENO). AIM: We studied the effect of storage conditions on the stability of nitric oxide (NO) in mylar balloons. METHODS: Exhaled air samples and calibration gases were stored in mylar balloons at 4, 21 and 37 degrees C, with or without silica gel. NO was measured after 0, 6, 9, 24 and 48 h. Scheffe F-tests were used to compare NO values. RESULTS: NO remained stable in balloons for 9 h at all temperatures, without silica gel. NO increased between 9 and 48 h, but only with low initial FENO. Silica gel increased variability. CONCLUSIONS: FENO in mylar balloons is stable for at least 9 h. The storage temperature is not critical, but silica gel increases variability.

Breath Tests↗

PubMed2003

Aerosol therapy and the fighting toddler: is administration during sleep an alternative?

Insufficient cooperation during administration of aerosols by pressurized metered dose inhaler (pMDI)/spacers is a problem in nearly 50% of treated children younger than 2 years. For these children, administration during sleep might be more efficient. However, it is unknown how much aerosol reaches the lungs during sleep. The aim of this study was to determine in vitro the lung dose in young children from a pMDI/spacer during sleep and while being awake. Breathing patterns were recorded by a pneumotachograph in 18 children (age 11 +/- 5.1 months) during sleep and wakefulness. Next, breathing patterns were replayed by a computer-controlled breathing simulator to which an anatomically correct nose-throat model of a 9-month-old child was attached. One puff of budesonide (200 microg) was administered to the model via a metal spacer. Aerosol was trapped in a filter placed between model and breathing simulator. The amount of budesonide on the filter (5 lung dose) was analyzed by HPLC. For each of the 36 breathing patterns, lung dose was measured in triplicate. The sleep breathing patterns had significantly lower respiratory rate and peak inspiratory flows, and smaller variability in respiratory rate, tidal volume, and peak inspiratory flows. Lung dose (mean +/- SD) was 6.5 +/- 3.2 and 11.3 +/- 3.9 microg (p = 0.004) for the wake and sleep breathing pattern, respectively. This infant model-study shows that the lung dose of budesonide by pMDI/spacer is significantly higher during sleep compared to inhalation during wake breathing. Administration of aerosols during sleep might, therefore, be an efficient alternative for uncooperative toddlers.

Administration, Inhalation↗

PubMed2003

Asthma remission: does it exist?

Subjects believed to have grown out of asthma often develop symptoms again later in life. Ongoing airway inflammation may determine the risk of relapse, although the mechanisms involved are still misunderstood. Additionally, patients with asthma during childhood may develop irreversible airflow obstruction ( airway remodeling) as a result of chronic airway inflammation. Recently, airway inflammation and remodeling could be demonstrated in bronchial biopsy specimens from young adults who considered themselves grown out of asthma. It is also shown that evidence of airway inflammation and remodeling can be obtained noninvasively, thereby providing the opportunity to monitor disease activity. If chronic airway inflammation and/or remodeling are consistent findings in asymptomatic subjects with a history of atopic asthma, the question arises whether natural history can be positively altered with prolonged antiinflammatory therapy. Benefits of long-term prognosis are, however, not yet shown. Since epidemiologic work has demonstrated that a certain percentage of subjects with apparently outgrown atopic asthma remains asymptomatic without needing therapy for the rest of their lives, it can be argued that "asthma remission does exist." The question is whether this percentage can be increased with prolonged antiinflammatory therapy and regular control.

Adolescent↗

PubMed2002

Worsening of V'maxFRC in infants with chronic lung disease in the first year of life: a more favorable outcome after high-frequency oscillation ventilation.

Little is known about the development of maximal flow at functional residual capacity, a measure of airway patency, in infants with chronic lung disease (CLD). In a follow-up study, we evaluated V'maxFRC in very low birth weight infants with CLD, treated with high-frequency oscillation ventilation (HFOV) or conventional mechanical ventilation. In 36 infants with CLD, V'maxFRC was evaluated at 6 and/or 12 months corrected age, and the relationship between perinatal factors and lung function was studied. Mean (SD) birth weight and gestational age were 837 (152) g and 26.8 (1.7) weeks, respectively. At 6 and 12 months, mean V'maxFRC was significantly below normal. Between 6 and 12 months, there was a mean (95% confidence interval) reduction in V'maxFRC (Z score) of 0.5 (0.2-0.7) (p < 0.001). At 12 months, the mean V'maxFRC (Z score) was higher for children initially treated with HFOV (n = 15), as compared with children treated with conventional mechanical ventilation (n = 16): mean (95% confidence interval) difference was 0.6 (0.2-1.0) (p = 0.008). We conclude that very low birth weight infants with CLD have decreased V'maxFRC that worsen during the first year of life. Initial treatment with HFOV was associated with a more favorable outcome of V'maxFRC at 12 months corrected age.

Chronic Disease↗

PubMed2002

Placebo-controlled trial of house dust mite-impermeable mattress covers: effect on symptoms in early childhood.

We investigated the effect of house dust mite (HDM)-allergen avoidance on the development of respiratory symptoms, atopic dermatitis, and atopic sensitization by performing a double blind, placebo-controlled trial. In total, 1,282 allergic pregnant women were selected (416 received HDM allergen-impermeable mattress covers for the parents' and child's mattress in the third trimester of pregnancy [active], 394 received placebo covers, 472 received no intervention). Data on allergen exposure, clinical symptoms, and immunoglobulin E were collected prospectively. The prevalence of night cough without a cold in the second year of life was lower in the group with active covers compared with the group with placebo covers (adjusted odds ratio 0.65; 95% confidence interval 0.4-1.0). No effect of the intervention was seen on other respiratory symptoms, atopic dermatitis, and total and specific immunoglobulin E. It can be concluded that application of HDM-impermeable mattress covers on the child's and parents' beds reduced night cough, but not other respiratory symptoms, atopic dermatitis, and atopic sensitization in the first 2 years of life. Follow-up will determine the long-term effect of the intervention on the development of atopic disease.

Adult↗

PubMed2002

Feasibility of AsthmaCritic, a decision-support system for asthma and COPD which generates patient-specific feedback on routinely recorded data in general practice.

BACKGROUND: Introducing decision-support systems as a tool to stimulate the dissemination of clinical guidelines in daily practice has been disappointing. Researchers have argued that integration of such systems with clinical practice is a prerequisite for acceptance. The big question concerns the feasibility of a true integration--if only routinely recorded data are used for such a system, can patient-specific feedback be produced? OBJECTIVE: The aim of this study was to assess the feasibility of generating patient-specific feedback based on routinely recorded data in general practice by AsthmaCritic, a decision-support system for asthma and chronic obstructive pulmonary disease (COPD). METHODS: We built the decision-support system AsthmaCritic and assessed its ability to detect asthma and COPD patient records and generate patient-specific feedback by retrospective analysis of routinely recorded data in 103 713 electronic patient records from primary care practices. We grouped feedback into categories of comments by age group (<12 years and > or =12 years). The main outcome measures were the number and percentage of "triggered" (selected) asthma and COPD patient records, and the number and percentage of records on which AsthmaCritic produced at least one feedback comment during the 1-year study period, by category of comments. RESULTS: AsthmaCritic detected 8784 (8.5%) asthma and COPD patient records. During the study period, AsthmaCritic generated 255 664 feedback comments (mean 3.4 per patient visit). The most frequently generated category of comments in the case of patients aged > or =12 years was "non-compliant prescription" (23.7%), whereas the most frequent category in the case of patients <12 years was "non-compliant route" (31.1%). CONCLUSIONS: This study shows that, using routinely recorded data only, AsthmaCritic is able to detect asthma and COPD patient records for further analysis and to produce patient-specific feedback.

Adolescent↗

PubMed2002

Mite and pet allergen levels in homes of children born to allergic and nonallergic parents: the PIAMA study.

The Prevention and Incidence of Asthma and Mite Allergy (PIAMA) study is a birth cohort study that investigates the influence of allergen exposure on the development of allergy and asthma in the first several years of life. The objectives of this study were to investigate the relationship between a family history of allergy and/or asthma and exposure of newborn children to mite and pet allergen and to study the influence of different home and occupant characteristics on mite allergen exposure. Dust was sampled from the child's mattress and the parental mattress at 3 months after birth of the index child and analyzed for mite and pet allergens. Subjects were divided in groups according to history of asthma and allergy in their parents, and allergen exposure was studied in the different groups. Cat allergen exposure was significantly lower on parental mattresses in families with allergic mothers, but dog allergen exposure was not different. Mite allergen exposure was lower on parental mattresses in families with allergic mothers. Use of mite allergen-impermeable mattress covers reduced mite allergen exposure. Some other characteristics such as age of home and mattress were also found to influence mite allergen exposure. Parental mattresses in homes of allergic mothers had lower cat and mite (but not dog) allergen loadings than mattresses in homes of nonallergic parents. Paternal (as opposed to maternal) allergy seemed to have little influence.

Adult↗