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Biomedical subjects

H P Van Bever

Publications and source records attributed to H P Van Bever.

At least 19 recordsLinked to original sources
PubMed2005

Perinatal risk factors for sensitization, atopic dermatitis and wheezing during the first year of life (PIPO study).

OBJECTIVE: To evaluate the influence of perinatal environmental factors on early sensitization, atopic dermatitis and wheezing during the first year. METHODS: Information on pregnancy-related factors, parental atopic history, environmental factors and the clinical course of the infant until age one was gathered by questionnaires, as part of a prospective birth cohort study (Prospective study on the Influence of Perinatal factors on the Occurrence of asthma and allergies [PIPO-study]). Quantification of total and specific IgE was performed in 810 children and their parents. RESULTS: Early sensitization was found in 107/810 (13%) of the infants. Multiple regression analysis showed that specific IgE in fathers was a risk factor for early sensitization in their daughters (adjusted odds ratios (OR(adj)) 2.21 (95% confidence interval (CI) 1.10-4.49); P=0.03), whereas in boys, day care attendance was shown to be protective for early sensitization (OR(adj) 0.38 (95% CI 0.20-0.71); P=0.001). Atopic dermatitis occurred in 195/792 infants (25%). Specific IgE in the mother (OR(adj) 1.52 (95% CI 1.06-2.19); P=0.02) and in the infant (OR(adj) 4.20 (95% CI 2.63-6.68); P<0.001) were both risk factors for the occurence of atopic dermatitis, whereas postnatal exposure to cats was negatively associated with atopic dermatitis (OR(adj) 0.68 (0.47-0.97); P=0.03). Postnatal exposure to cigarette smoke (OR(adj) 3.31 (95% CI 1.79-6.09); P<0.001) and day care attendance (OR(adj) 1.96 (95% CI 1.18-3.23); P=0.009) were significantly associated with early wheezing, which occurred in 25% (197/795) of the infants. CONCLUSION: The effect of paternal sensitization and day care attendance on sensitization is gender dependent. Maternal sensitization predisposes for atopic dermatitis, whereas postnatal exposure to cats had a protective effect.

Allergens↗
PubMed2003

Differences in circulating dendritic cell subtypes in cord blood and peripheral blood of healthy and allergic children.

BACKGROUND: Different types of circulating dendritic cells have been described. Dendritic cells influence differentiation of naive T lymphocytes into T helper type 1 (Th1) and Th2 effector cells. OBJECTIVE: The purpose of this study was to evaluate the number of circulating DC subtypes in peripheral blood of allergic and healthy children and in cord blood of neonates from allergic and non-allergic parents. METHODS: Circulating dendritic cells were flow cytometrically identified in whole blood samples as lineage (CD3, CD14, CD16, CD19, CD20, CD56) negative, CD34 negative and HLA-DR-positive cells. According to the expression of CD123 and CD11c, different DC subtypes were identified. RESULTS: Apart from DC1 (CD11c+ CD123dim+) and DC2 (CD11c- CD123high+), a third DC population was described with less differentiated phenotypic characteristics, namely CD11c- CD123dim+, and therefore defined here as less differentiated DC (ldDC). These ldDC represented the major DC population in cord blood and showed an age-depended decrease. The highest level of ldDC was detected in children with atopic dermatitis, whereas asthmatic children showed the lowest ldDC counts. Furthermore, high-dose inhaled corticosteroid treatment in asthmatic children was related to a decreased ldDC number. The number of circulating DC2 was significantly lower in allergic children, especially in asthmatics, compared to healthy children. In cord blood, no differences in DC subtypes were detectable between neonates at low and high risk for allergic disorders. CONCLUSION: These results indicate that, apart from DC1 and DC2, a third population of dendritic cells, identified as CD11c- CD123dim+ cells and defined as less differentiated DC, must be considered in the evaluation of circulating DC. Furthermore, DC2 counts were decreased in allergic children, especially in asthmatics, which might be the consequence of an increased recruitment to the target organs.

Adolescent↗
PubMed2002

Critical evaluation of prognostic factors in childhood asthma.

Current knowledge of the natural history of asthma is improving through the establishment of a more precise definition of asthma linked with information from a number of large-scale longitudinal studies. Risk factors for the development of childhood asthma are now more clearly understood. They include gender, atopic status, genetic and familial factors, respiratory infections, and outdoor and indoor pollution (1). In the present review two types of asthma and their prognosis will be discussed: (1) Asthma in preschool children and its risk factors for evolution towards persistent childhood asthma. (2) Asthma in older children and its risk factors for evolution towards adult asthma.

Adolescent↗
PubMed2001

The role of inflammation in the development of chronic lung disease in neonates.

UNLABELLED: Chronic lung disease (CLD) has been associated with chorioamnionitis and upper respiratory tract colonisation with Ureaplasma urealyticum. The aim of this review is to describe the increasing evidence that inflammation plays a critical role in the early stages of CLD of the neonate. Ongoing lung damage in the premature infant may be caused by failure to downregulate and control this inflammatory response. Tumour necrosis factor alpha (TNF-alpha), interleukin-6 (IL-6) and IL-8 are important pro-inflammatory cytokines of which IL-8 is an important chemotactic factor in the lung. Data suggest that preterm newborns with lung inflammation may be unable to activate the anti-inflammatory cytokine IL-10. Therefore, early post-natal anti-inflammatory therapy could help in preventing development of CLD. Prophylactic dexamethasone therapy cannot yet be recommended. There are a number of potential interactions between surfactant and cytokine effects on the preterm lung which have not been evaluated. Surfactant protein A may be an important modulator of the immune response to lung injury. The role of high-frequency ventilation in the prevention of CLD still remains unclear. CONCLUSION: Many aspects of the pathogenesis of the inflammatory response in the development of chronic lung disease remain to be elucidated. Further research to identify preterm infants at highest risk for the development of this multifactorial and complex disease is needed.

Chorioamnionitis↗
PubMed2001

Effect of salbutamol on lung function parameters of healthy children.

UNLABELLED: In the present study, the effect of 200 microg salbutamol compared to placebo was evaluated on lung function parameters of 37 healthy children aged 7-14 years. Salbutamol or placebo were administered, using a single blind study design, and spirometry was performed before and after 10 min of inhalation. At the time of the study, all children were symptom-free and had not suffered from any respiratory infection during the previous 4 weeks. The administration of salbutamol resulted in a significant increase of mean forced expiratory volume in 1 s (111%-115%, P<0.05), maximal expiratory flow at 50% of forced vital capacity (101%-110%, P<0.05) and maximal expiratory flow at 25 % of forced vital capacity (96%-115%, P<0.05). The administration of placebo resulted in no significant change in lung function parameters. CONCLUSION: The administration of 200 microg salbutamol results in the occurrence of a small but significant bronchodilation in healthy, non-asthmatic children.

Adolescent↗
PubMed2001

Higher occurrence of asthma-related symptoms in an urban than a suburban area in adults, but not in children.

In young adults, a higher occurrence of asthma-related symptoms was found in an urban than an adjacent suburban area in a survey performed in 1991. The authors now wondered whether such differences could be established in other age groups. The present study (in 1996) included 14,299 subjects, aged 5-75 yrs, of a random sample of the general population in the same two adjacent areas: the centre of Antwerp (Belgium) and its south suburban border. The standardized European Community Respiratory Health Survey (ECRHS) and International Study of Asthma and Allergies in Childhood (ISAAC) questionnaires were used to assess the occurrence of asthma-related symptoms. Higher rates were confirmed in urban compared to suburban Antwerp in adults (20-75 yrs), but no such area differences were found in children (5-8 and 12-15 yrs). Adjustment for a number of recorded risk factors did not seem to affect the area differences in asthma-related symptoms. Comparing the survey results of 1991 and 1996 in 20-44 yr old adults, the findings suggest a slight increase in reported respiratory symptoms in both areas. A higher occurrence of asthma symptoms was observed in the urban than suburban area in adults, but not in children. This might be explained by a progressive effect of long-term exposure to the "urban environment". However, longitudinal studies are necessary to further clarify the factors accounting for these age-related area differences.

Adolescent↗
PubMed2000

Encephalomyelitis-associated antimyelin autoreactivity induced by streptococcal exotoxins.

OBJECTIVE: After implicating Streptococcus pyogenes as causing acute disseminated encephalomyelitis (ADEM) in a child, we wanted to prove that in vivo activation of autoreactive T lymphocytes by superantigens of this Streptococcus contributed to the dramatic demyelination. BACKGROUND: ADEM is a demyelinating disorder of the CNS sharing many similarities with MS. Demyelination in MS is considered to be the result of an autoimmune process mediated by autoreactive T lymphocytes with specificity for myelin antigens. METHODS: Phenotypic analysis and proliferation assays on blood monocytes, as well as isolation of myelin basic protein (MBP)-reactive T-cell lines/clones; and TCR repertorium analysis by PCR-ELISA and cytokine production. RESULTS: 1) The blood T-cell receptor (TCR) repertoire was compatible with in vivo expansion induced by S. pyogenes exotoxins. 2) TCR expression analysis indicated clonal expansion of CD8+ MBP-reactive T cells, suggesting in vivo activation. MBP-reactive T cells showed crossreactivity to S. pyogenes supernatant and exotoxins. 3) Cytokine mRNA quantification of the mononuclear cells revealed a Th2-biased profile. CONCLUSION: In vivo exposure to S. pyogenes may have induced activation of pathogenic myelin reactive T cells, contributing to the dramatic inflammatory demyelination.

Autoimmunity↗
PubMed2000

Long-term effects of specific immunotherapy, administered during childhood, in asthmatic patients allergic to either house-dust mite or to both house-dust mite and grass pollen.

In a retrospective study, asthmatic patients allergic to either house-dust mite (HDM) (Dermatophagoides pteronyssinus) (n = 34) or to both HDM and grass pollen (GP) (n = 14), and who were treated with specific immunotherapy (SIT) during childhood (mean duration of SIT: 61 +/- 9.70 months), were re-evaluated in early adulthood after mean cessation of SIT for 9.3 +/- 2.76 years. The results were compared to those of a control group of asthmatic patients (n = 42) with comparable asthma features, who were treated with appropriate antiasthmatic drugs during childhood, but who never received SIT. Re-evaluation was carried out with a standardized questionnaire, skin prick tests (SPT), and lung-function assessments. At the time of re-evaluation, the mean age in the SIT-treated group was 23.1 +/- 3.50 years; in the control group, it was 22.7 +/- 3.40 years. At re-evaluation, the risk of frequent asthmatic symptoms was three times higher in the control group than in the SIT-treated group (prevalence ratio: 3.43; P = 0.0006). The frequent use of antiasthmatic medication was also more pronounced in the control group, although the difference was not statistically significant (P=0.38). Lung-function parameters and results of SPT with HDM were comparable in both groups. It is concluded that SIT has long-term effects on asthmatic symptoms in young adults.

Adult↗
PubMed2000

Determination of T-cell subpopulations and intracellular cytokine production (interleukin-2, interleukin-4, and interferon-gamma) by cord blood T-lymphocytes of neonates from atopic and non-atopic parents.

This report describes the results of a prospective study on immunological markers in cord blood for the prediction of allergic diseases in children. First we evaluated methodological aspects of the flow cytometric technique on cord blood cytokine measurements. Subsequently, the T-cell subsets and percentage of cytokine-producing cord blood T-helper (Th) and T-suppressor/cytotoxic lymphocytes of neonates from atopic and non-atopic parents were compared. A group of 33 healthy, full-term newborn infants of whom 23/33 were at risk for atopy (i.e. having at least one parent with one or more atopic symptoms and positive specific immunoglobulin E [IgE] to at least one common inhalant allergen) was studied. A flow cytometric technique was used to analyze cord blood T-cell subsets and to determine the percentage of interleukin (IL)-2-, IL-4-, and interferon-gamma (IFN-gamma)-producing cord blood Th and T-suppressor/cytotoxic lymphocytes following stimulation with phorbol 12-myristate 13-acetate (PMA) and ionomycin. The percentage of CD3 (T lymphocytes), CD3+ CD4+ (Th lymphocytes), CD3+ CD8+ (T-suppressor/cytotoxic lymphocytes), CD19+ (B lymphocytes), CD3+ CD4+ CD45RO+ (memory Th lymphocytes), and CD3+ CD4+ CD45RA+ (naive Th lymphocytes) cells was unrelated to parental atopic status. PMA stimulation augmented the percentage of IL-2- and IFN-gamma-producing Th and T-suppressor/cytotoxic lymphocytes, whereas the number of IL-4-producing T lymphocytes remained very low or undetectable. No differences in the percentage of TL-2-, IL-4- and IFN-gamma-producing Th and T-suppressor/cytotoxic lymphocytes were found between neonates from atopic and non-atopic parents. These results will be re-evaluated when the atopic status of the children at the age of 1 and 2 years can be assessed.

Animals↗
PubMed2000

Does the use of antibiotics in early childhood increase the risk of asthma and allergic disease?

BACKGROUND: One of the mechanisms evoked to explain the increasing prevalences of asthma and allergy, in particular among children, is the 'Western lifestyle' or 'hygiene' hypothesis. As early childhood infections are assumed to hold a protective effect on the development of asthma and allergies, the use of antibiotics at that sensitive age may lead to an increased risk of asthma and allergy. OBJECTIVE: The aim of this study is to investigate the association between the use of antibiotics in the first year of life and the subsequent development of asthma and allergic disorders. METHODS: In a population-based sample of 7-and-8-year-old children questionnaire and skin prick test data were collected from 1206 and 675 subjects, respectively. Prevalence rates of asthma, allergic disorders and skin test positivity were compared between children with and without early life use of antibiotics, taking into account other possible risk factors including early respiratory infections. The effect of genetic predisposition was investigated by stratified analyses of children with and without parental hay fever. RESULTS: The use of antibiotics during the first year of life was significantly associated with asthma (OR = 1.7, 95% CI 1.0-3.1), hay fever (OR = 2.3, 95% CI 1.3-3.8) and eczema (OR = 1.3, 95% CI 1.0-1.8). No significant relationship was found with skin test positivity (OR = 1.1, 95% CI 0.7-1.7). After stratification for the presence of parental hay fever, children without parental hay fever did not show any significant associations between antibiotics use and asthma or allergy, whereas in children with parental hay fever the use of antibiotics was significantly related with asthma (OR = 2.3, 95% CI 1.1-5.1), hay fever (OR = 2.8, 95% CI 1.5-5.1) and eczema (OR = 1.6, 95% CI 1.0-2.6), and of borderline statistical significance with skin test positivity (OR = 1.6, 95% CI 0.9-3.0). CONCLUSION: Early childhood use of antibiotics is associated with an increased risk of developing asthma and allergic disorders in children who are predisposed to atopic immune responses. These findings support recent immunological understanding of the maturation of the immune system.

Anti-Bacterial Agents↗
PubMed1999

Lung function measures and their relationship to respiratory symptoms in 7- and 8-year-old children.

Abnormal pulmonary function in childhood is a well-known risk factor for lung function impairment in adult life. It is therefore of clinical interest to recognize lower pulmonary function in childhood. We investigated the association between asthma-like respiratory symptoms and the lung function parameters FVC, FEV1, and FEF(25-75) in a population-based sample of 402 schoolchildren, aged 7 and 8 years, using linear regression analyses. Without accounting for other respiratory symptoms, wheeze, exercise-induced wheeze, chronic cough, and history of wheezy bronchitis or lower respiratory infections in early childhood were significantly associated with reduced lung function. After stepwise elimination of symptoms from the regression models, only exercise-induced wheeze (FEV1, -15%pred, FEF(25-75), -21%pred) and a history of chronic cough (FEV1, -5%pred; FEF(25-75), -11%pred) remained significant predictors of decreased lung function. After adjustment for different variability, no significant differences were seen between the effects of symptoms on the flow measurements FEV1 and FEF(25-75). We conclude that children who report exercise-induced wheeze and/or chronic cough may have a considerable deficit in lung function at early school age.

Asthma↗
PubMed1999

Does treatment of asthmatic children with inhaled corticosteroids affect their adult height?

In this retrospective study, adult height was assessed in young adult asthmatics who were treated with inhaled corticosteroids (ICs) during childhood (n = 42; 26 boys) and compared to those obtained in asthmatic patients who were never treated with ICs during childhood (n = 43; 23 boys). Standing height of all subjects and their parents was measured. Height data were analyzed using actual length and target height in centimeters, standard deviation scores (SDS), and difference between adult height of the patients and their target height (adult height minus target height). Mean adult height was the same in subjects who took ICs during childhood as compared to those who had never received ICs (boys: 179.3cm+/-6.8 vs. 180.4 cm+/-5.6; girls: 165.8 cm+/-7.5 vs. 167.7 cm+/-7.2). SDS of adult height was also not different between the two groups: in subjects who did not take ICs it was 0.89+/-1.00, while in those who took ICs it was 0.66+/-1.10 (P = 0.31). SDS of target height was also not different between the two groups: in subjects not taking ICs it was 0.95+/-0.86, while in those who took ICs it was 0.28+/-0.76 (P = 0.30). However, subjects who took ICs during childhood showed a statistically significant lower value of adult height minus target height than those who never took ICs (whole group: -0.003+/-5.9 vs. 2.54 +/-4.8, P = 0.03 ; boys: 0.004+/-5.8 vs. 3.09+/-4.5, P = 0.04 ; girls: -0.075+/-6.3 vs. 1.91+/-5.2, P = 0.31). Patients on ICs during childhood who had ever been hospitalized for asthma showed a lower value for adult height minus target height than those who took ICs but were never hospitalized (-3.08+/-7.8 vs. 1.06+/-4.8, P = 0.046). A logistic regression analysis predicting growth impairment showed that the best-fitting model was one that used only ICs as a dependent variable (crude odds ratio, 3.3; 95% CI, 1.3-8.4). Patients who were treated with ICs in combination with intranasal corticosteroids (treatment for rhinitis) tended to have a lower value of adult height minus target height than the other children, but the difference was not statistically significant (P = 0.07). We conclude that although adult height was the same in young adults who were treated with ICs during childhood compared to those who were not treated with ICs during childhood, there was a statistically significant difference between the two groups for adult height minus target height, suggesting mild growth retardation in patients who took ICs during childhood. These findings may be explained by the use of ICs, but it seems more likely that a difference in asthma severity between both groups was responsible for it.

Adolescent↗
PubMed1999

Croup and recurrent croup: their association with asthma and allergy. An epidemiological study on 5-8-year-old children.

UNLABELLED: The cumulative incidence (i.e. lifetime prevalence) of croup and recurrent croup (RC) was investigated by questionnaire in a large group (n = 5756) of 5-8-year-old children (mean age: 6.8 +/- 0.6 years) and the risk for asthma and/or wheezing in children with croup and RC assessed. In a random sample of the children, skin prick testing with common inhalant allergens (n = 614) and spirometry (n = 305) were performed and the results were compared between children with or without croup or RC. Of the children, 15.5% had suffered from croup, while 5.0% had had RC. The cumulative incidence was higher in boys than in girls (P < 0.05). In the children with croup or RC an increased risk for wheezing, asthma, usage of anti-asthma medication, rhinitis and hay fever was found (P < 0.01). There was no difference in the prevalence of positive skin prick tests between children with and without croup or RC. Mean percentage predicted forced expiratory volume in 1 s, forced vital capacity and peak expiratory flow was not different between children with and without croup or RC. However, children who had suffered from croup (with or without wheezing) had a lower mean percentage predicted forced expiratory flow at both 50% and 75% of forced vital capacity than those without croup (P = 0.002). A family history of hay fever, chronic bronchitis and eczema was associated with the presence of croup or RC (P < 0.01), while this was hardly the case for a family history of asthma. CONCLUSION: Croup and recurrent croup are associated with bronchial asthma. The association seems essentially based on the presence of hyperreactive airways and less on the presence of atopy, although the latter can be considered an aggravating factor.

Asthma↗
PubMed1999

Gender differences in respiratory, nasal and skin symptoms: 6-7 versus 13-14-year-old children.

ISAAC questionnaires were completed by the parents of 6432 children, aged 6-7 y and by themselves by 2864 children 13-14-y-old. Prevalence rates of respiratory and nasal symptoms and a diagnosis of asthma and hay fever were higher in 6-7-y-old boys than in girls, while girls aged 13-14 y had higher rates for most symptoms, except asthma. Underdiagnosis of asthma in 13-14-y-old girls cannot be excluded as an explanation, but our data suggest under-reporting of respiratory and nasal symptoms in 13-14-y-old boys.

Adolescent↗
PubMed1998

Construction of an internal control for the detection of Chlamydia pneumoniae by PCR.

For the detection of Chlamydia pneumoniae by polymerase chain reaction (PCR) in respiratory samples, an internal control was constructed to monitor the efficiency of amplification in each reaction. The internal control was designed in a way that the same primer pair can be used to amplify the internal control and target DNA. Nasopharyngeal aspirates of children suffering from asthma (> 2 years of age; 24 patients) or bronchiolitis (< 2 years of age; 47 patients) were analysed for the presence of C. pneumoniae, using the internal control in each amplification reaction. Two specimens from asthma patients, both children of 8 years old, were positive for C. pneumoniae. The number of cases studied is too small to draw conclusions regarding the incidence of C. pneumoniae in different age categories in children.

Asthma↗
PubMed1997

Study of the bronchodilating effect of three doses of nebulized oxitropium bromide in asthmatic preschool children using the forced oscillation technique.

UNLABELLED: The aim of this study was to evaluate the bronchodilating capacity of nebulized oxitropium bromide (OB) in preschool asthmatic children and to determine an appropriate dose for usage in this age group. The trial enrolled 20 patients with moderate to severe stable asthma aged between 3.2 and 6.2 years (mean 4.7). Applying a placebo controlled, double-blind design, the effect of placebo was compared with three different doses of OB (375, 750 and 1500 micrograms) and with 400 micrograms fenoterol. The three different doses of OB resulted in a highly significant bronchodilation within 15 min after administration. The observed bronchodilation was comparable between the three doses during the first 2 h. However, after 4 h the lowest dose was significantly less powerful than the highest dose. Compared to the additional bronchodilation induced by fenoterol, no difference was found with the degree of bronchodilation of OB which occurred during the first 2 h. Furthermore, after 4 h only the lowest dose of OB was significantly less powerful than fenoterol assessed 10 min following a single 400 micrograms dose. CONCLUSION: Oxitropium bromide is a potent and long-acting bronchodilator in preschool children at a dose of 750 micrograms and 1500 micrograms. No side-effects were observed. The exact duration of action remains uncertain, but even 4 h after inhaling 750 or 1500 micrograms of OB no additive bronchodilation induced by fenoterol could be observed.

Aerosols↗
PubMed1996

Functional residual capacity in healthy preschool children.

The purpose of this study was to evaluate the feasibility of routine functional residual capacity (FRC) measurements in healthy preschool children aged 2.7-6.4 yrs. Furthermore, accuracy and reproducibility were investigated and normal values were collected. A mass-produced closed-circuit helium dilution device (rolling seal) was used. Selection of the 113 healthy children (from the 571 measured) was based on an extensive personal and family history questionnaire and on clinical examination before measurements were performed. With three successive attempts it was possible to achieve at least two reproducible measurements in 73% of the children (repeatability coefficient 95.3 mL). The main problems were leakage at the corner of the mouth and irregular breathing pattern. The mean time to perform a measurement was 113 s. Mean FRC was significantly higher in boys than in girls: 778 versus 739 mL for a body length of 110 cm (p<0.05). FRC correlated with height (H) (r=0.69), weight (W) (r=0.56), age (A) (r=0.62) and all three combined (r=0.70): FRC = -534.89 + 1.84 x W (kg) + 10.07 x H (cm) + 2.51 x A (months). When a power or exponential function was used to describe FRC as a function of height, the results were not superior to the linear regression (r=0.69): FRC (mL) = -766.2 + 13.8 x H (cm) (r=0.69) or FRC (L) = 0.620 x H (m)(2.03) (r=0.69) or FRC (mL)= 99.5 x e(0.018xH (cm)) (r=0.69). Among these, we recommend the power function because it will better fit broader height ranges. Reliable functional residual capacity measurements can be routinely performed in preschool children with a mass-produced device. Reference values were collected for children 95-125 cm in height.

Body Height↗