[Cystic fibrosis; pathophysiology of electrolyte transport and potential influence of amiloride].
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Amiloride↗
Biomedical subjects
K Knol
Publications and source records attributed to K Knol.
Influence of a positive family history and associated allergic diseases on the natural course of asthma.
The outcome of childhood asthma was studied in a cohort of 406 asthmatic children, with emphasis on the influence of family history for allergic disease, as well as the influence of associated allergic diseases on prognosis. Sixty-two per cent had a positive family history for atopy. In young adulthood no differences, either in symptoms or lung function were demonstrated in comparison to subjects with a negative family history. Fifty-two per cent of the children had no other allergic disease, 48% had either eczema or hay fever or both. When subjects were stratified based on associated allergic disease, no differences in outcome in adulthood were revealed either. It is concluded that neither a positive family history, nor concurrent associated allergic diseases in the child contribute to the prognosis of asthma from childhood to young adulthood. Therefore, environmental factors as well as patient characteristics (including lung function level, level of bronchial responsiveness) are likely to be more important for the prognosis.
Adult↗
Adrenergic response in children with asthma on exogenous stimuli.
In asthmatic children it was investigated whether the degree of impairment of the adrenergic response on exogenous stimuli is related to the magnitude of the 24-hour amplitude in airflow obstructions. Urinary-adrenaline and noradrenaline excretion after house dust mite (HDM) inhalation and after exercise was measured. Nine children with (group I), and nine without increased airflow obstruction overnight (group II) and nine age matched healthy children (group C) were included in the study. All patients showed an early obstructive reaction (EOR) after HDM challenge. Six children in group I and five in group II developed an EOR on exercise. A significant increase in urinary adrenaline excretion was observed after exercise in the control group (P < 0.05, values on the control and challenge day being 5.4 +/- 0.9 and 10.0 +/- 1.6 mumol/mol creat.). The same occurred for noradrenaline (P < 0.01, values being 28.2 +/- 2.5 and 49.0 +/- 5.7 mumol/mol creat.). Adrenergic response after both stimuli was impaired in the asthmatic groups, in group I more pronounced than in group II. Values from group I for adrenaline on the control day, HDM and exercise challenge were 6.0 +/- 0.8, 4.7 +/- 0.6, 6.0 +/- 1.0 and for noradrenaline 36.1 +/- 2.7, 27.2 +/- 2.3, 38.4 +/- 4.9 mumol/mol creat., respectively. Values from group II for adrenaline on these days were 5.6 42- 1.0, 3.7 42- 0.6 and 9.0 +/- 1.3 and for noradrenaline 28.3 +/- 3.2, 22.4 +/- 2.5, 41.3 +/- 5.9 mumol/mol creat., respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
Adolescent↗
Smoking habits in medical students and physicians in Groningen, The Netherlands.
Smoking habits and attitudes towards smoking of medical students (n = 725), house officers (n = 126) and consultants (n = 236) of the University Hospital of Groningen were studied, in 1989 by means of a World Health Organization (WHO) questionnaire. Overall response rate was 84%. Twenty seven percent of the medical students are current smokers, 28% of the house officers and 34% of the consultants. There is a remarkable difference among medical specialists i.e: smoking prevalence is highest among psychiatrists and lowest among paediatricians. The prevalence of smoking in medical students and house officers is lower than in the Dutch population. Smoking habits of the consultants are similar to those of the general population. About 75% of the doctors reported having no experience with smoking cessation programmes. Doctors report a need for more skills and knowledge on smoking cessation programmes.
Adult↗
Repeated provocation tests in asthmatic children for testing tachyphylaxis to histamine.
Tachyphylaxis to histamine was investigated in 16 children, aged 7-15 years, with mild asthma. Three consecutive histamine challenges were performed at intervals of 24 hours and 1 hour, respectively. No significant differences in IVC, FEV1, and PC20-histamine values between the three measurements were observed. After a 24 hour interval there was no difference in percentage fall of FEV1, but there was a slight (not significant) decrease in fall of FEV1 after a 1 hour interval. The PC20-histamine values showed good reproducibility with a 24 hour as well as with a 1-hour period between the tests (geometric mean PC20, 2.04 mg/mL +/- 3.50 %SD, 1.96 mg/mL +/- 4.37 %SD, 2.17 mg/mL +/- 4.12 %SD; correlation coefficients for a 24 hour interval, r = 0.87 and for a one-hour interval, r = 0.94 (P less than 0.01]. We conclude that in children there is no strong evidence for tachyphylaxis to histamine. Our results differ from studies on tachyphylaxis in adult asthmatics. Possibly different mechanisms exist in children and in adults.
Adolescent↗
Nocturnal airflow obstruction, histamine, and the autonomic central nervous system in children with allergic asthma.
A study was carried out to investigate whether an imbalance in the autonomic nervous system or release of histamine, or both, is responsible for the nocturnal increase in airflow obstruction in asthmatic children. The study comprised 18 children with allergic asthma, nine with (group 1) and nine without (group 2) nocturnal airflow obstruction, and an age matched control group. All drugs were withheld for three days before and during the study. On day 4 each child was admitted to hospital and a series of measurements was made every four hours for 24 hours. These included measurements of the forced expiratory volume in one second (FEV1), heart rate and sinus arrhythmia gap from an electrocardiogram (an indirect measure of parasympathetic activity) and urine sampling for determination of catecholamine and N'-methylhistamine concentrations (measures of sympathetic activity and histamine release respectively). Urinary N'-methylhistamine excretion was significantly higher over the 24 hours in children in group 1 than in children in group 2, and overnight values were also significantly higher in children in group 1 than those in group 2. Mean (SEM) values (mumol/mol creatinine) were 154.6 (11.2) in group 1 and 110 (11.2) in group 2 for 2400-0400 hours samples and 139.2 (13.1) and 101.2 (10.6) 0400-0800 hours samples. There was no evidence of decreased sympathetic or increased parasympathetic activity in association with the nocturnal airflow obstruction; noradrenaline concentrations were increased in group 1. These observations indicate that nocturnal airflow obstruction is associated with increased release of histamine overnight.
Adolescent↗
Budesonide and terbutaline or terbutaline alone in children with mild asthma: effects on bronchial hyperresponsiveness and diurnal variation in peak flow.
The effects of treatment with budesonide (200 micrograms twice daily) and terbutaline (500 micrograms four times daily) has been compared with the effects of placebo and terbutaline in 27 children with mild asthma, aged 7-14 years, in a double blind, randomised placebo controlled study over eight weeks. Bronchial responsiveness (PC20 histamine), lung function, the amplitude of diurnal variation in peak expiratory flow (PEF), and symptom scores were measured. Baseline FEV1 was over 70% predicted and PC20 histamine less than 8 mg/ml. Twelve children were treated with budesonide and terbutaline and 15 with placebo and terbutaline. After four and eight weeks of treatment the change in PC20 was significantly greater after budesonide and terbutaline than after terbutaline alone by 2.1 (95% CI 0.5-3.8) and 1.3 (95% CI 0.1-2.5) doubling doses respectively. Mean FEV1 did not change in either group. The change in afternoon and nocturnal PEF was significantly greater after budesonide and terbutaline than after terbutaline alone. The amplitude of diurnal variation in PEF did not change significantly in either group. Peak flow reversibility decreased in the budesonide group. There were no differences between treatments for cough and dyspnoea, but wheeze improved in the budesonide group. The children with mild asthma treated with budesonide and terbutaline showed improvement in bronchial responsiveness, afternoon and nocturnal PEF, and symptoms of wheeze and a fall in peak flow reversibility by comparison with those who received terbutaline alone.
Administration, Inhalation↗
Airway responsiveness in childhood as a predictor of the outcome of asthma in adulthood.
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Adolescent↗
[Bronchial hyperreactivity].
Bronchial hyperreactivity, the abnormal reaction of the airways on non-allergic stimuli, is a feature of patients with chronic nonspecific lung disease. Several underlying mechanisms such as the neurogenic pathways, inflammatory cells and mediators, increased vascular leakage, epithelial damage and pathological changes in airway smooth muscle seem to play a role of importance in bronchial hyperreactivity. Recent developments in these research fields produce more clarity in the mutual connection of these factors in relation to the phenomenon of bronchial hyperreactivity.
Adrenergic Fibers↗
[Smoking behavior of medical students, house officers and specialists in Groningen, 1989].
Smoking habits and attitudes towards smoking of medical students (n = 725), house officers (n = 126) and consultants (n = 236) of the University Hospital of Groningen were studied in 1989 using a WHO questionnaire. Overall response was 84%. Twenty-seven percent of the medical students, 28% of the house officers and 34% of the consultants are current smokers. The prevalence of smoking in medical students and house officers is lower than that in the Dutch population. Smoking habits of consultants are similar to the general population. The prevalence of smoking Dutch physicians which was 56% in 1983 is decreasing rapidly. Doctors report they want more information about smoking cessation programs.
Adult↗
Nocturnal asthma, histamine and vagal activity.
In a study of two groups of nine allergic asthmatic children, consisting of one group with (group I) and one group without (group II) increased nocturnal airflow obstruction, we determined whether an increase in vagal activity, or inflammatory mediators like histamine are responsible for the nocturnal increase in airflow obstruction. The results of investigations in the two groups of asthmatics were compared to the results of an age matched control group. Forced expiratory volume in one second (FEV1) and electrocardiogram recordings of one minute were obtained every 4 hours during 24 hours. Heart rate and sinus arrhythmia gap were used to express vagal activity indirectly. N tau-methylhistamine was determined in urine samples collected in periods of 4 hours between the measurements. In group I, overall N tau-methylhistamine excretion was on a higher level than in both other groups, and was significantly higher overnight. Parasympathetic stimulation did not seem of importance to the increase of airflow obstruction at night.
Adolescent↗
Guidance of children and adolescents with cystic fibrosis.
Cystic fibrosis is the most common serious genetic disorder in people of European descent. Treatment of these patients is ongoing throughout life and until now has been aimed at the consequences and is still not curative. Over the past 10-20 years, there has been a dramatic improvement of mortality rates for cystic fibrosis, due in large part to advances in medical care. The average age of survival for young people with cystic fibrosis is pushing well into the 20s with one third living into their 30s. Consequently, education plays a major role in management of patients with cystic fibrosis, and starts directly after being sure of the diagnosis. Growing up, these patients experience a lot of problems, and these are especially marked in the adolescent. A special problem, for many cystic fibrosis patients is becoming an adult. Continuity in care for these patients from the pediatric to the adult department is not always guaranteed. It is concluded that patients with cystic fibrosis should be treated in specialized centers, and such treatment cannot be carried out sufficiently by one person, but has to be embedded in a team of caregivers.
Adolescent↗
Change in airway responsiveness to inhaled house dust from childhood to adulthood.
Between 1966 and 1969, housedust (HD) inhalation provocation tests were performed in 119 children with asthma. Between 1984 and 1987, 101 of the 119 subjects (85%) were reinvestigated. Thirty-one of these 101 adults who participated in a study on the outcome of childhood asthma were rechallenged with HD after a mean interval of 16 years to establish the change in airway responsiveness to HD from childhood to adult life. In the childhood study in these 31 subjects, six had no response (NAR); six, an early response (EAR); eight, a late (LAR); and eleven subjects, an EAR followed by an LAR (dual asthmatic response [DAR]) to the inhalation of HD. In the second survey, two of the subjects with NAR in the first study had a bronchoconstrictor response to HD. Five subjects with an EAR or an LAR response in childhood had NAR as an adult. The eleven subjects with a DAR during childhood also had a response to HD as an adult; five had an EAR, and six adults again had a DAR. Eleven of the 13 adults (85%) with current respiratory symptoms had a response to HD during the second survey. Although they were symptom free, 11 of the other 18 adults (61%) responded on inhalation of HD. One of the 18 subjects without (6%), and six of the 13 subjects (46%) with current respiratory symptoms, had a provocative concentration of histamine in FEV1 10% of baseline less than or equal to 16 mg/ml. We conclude that, although respiratory symptoms disappear in one half the children with asthma and although adults may believe that they have outgrown their disease, adults still have the potency to respond to inhaled allergens. Most children do outgrow their respiratory symptoms but not the susceptibility of their airways to allergens.
Adult↗
Allergy in subjects with asthma from childhood to adulthood.
We studied the change from childhood to adulthood in skin test reactivity to house dust, animal dander, grass pollen, and molds, and, in addition, the change in number of blood eosinophils. The study was carried out in a group of 119 children with asthma, aged 6 to 14 years first observed between 1966 and 1969. In the present study, 101 subjects (85%) were reinvestigated after a mean period of 16 years; 43% had current symptoms. Skin test reactivity to all allergens and the number of subjects with positive skin tests to more than one allergen increased from childhood to adulthood. Subjects with allergic rhinitis (38%) had a higher number of positive skin tests to grass pollen in both childhood and adulthood than subjects without allergic rhinitis. Fifty-three children and 10 adults had atopic dermatitis. Atopic dermatitis occurred with equal frequency in children who did and in children who did not have current symptoms later in life. No differences in skin test reactivity to allergens were found between smoking and nonsmoking subjects. Although the smoking period was relatively short, smoking was correlated with eosinophilia in adulthood. The mean number of eosinophils decreased significantly between the first and second survey. The outcome of childhood asthma as defined by current symptoms was not predicted by skin reactivity to allergens, eosinophilia, atopic dermatitis, or allergic rhinitis in childhood.
Adolescent↗
Respiratory infections and vascular rings.
Recurrent respiratory infections after the first years of life are not easily related to vascular rings as the cause of these infections. Therefore six cases of older children are presented in whom a vascular ring was the cause of their respiratory problems. None of them ever had stridor or swallowing problems in early infancy, and recurrent respiratory infections occurred later in life as a symptom of a vascular ring. Unfamiliarity with this association caused a delay in diagnosis and treatment in two patients and persistent lung damage in one child. Five of the 6 children recovered well after operation. The diagnosis can be made at an early stage if close inspection of the outline of the trachea on the chest radiograph shows an impression from the right side.
Aorta↗
Effects of neonatal screening for cystic fibrosis on reproduction, attitudes toward reproductive behaviour and genetic knowledge.
An evaluation was carried out into whether neonatal screening for Cystic Fibrosis could potentially prevent the birth of more affected children in the same family. Although CF was detected in more than 50% within the first year of life in those cases where a diagnosis was made on clinical symptoms, in these families 10 children -- among whom two with CF -- were born prior to the CF diagnosis. With neonatal screening, no pregnancies were started before the CF-diagnosis. No differences were found in attitudes toward further reproduction and understanding of important genetic facts. Although prenatal diagnosis was not yet possible at the time of the study, approximately 50% of the parents showed a positive attitude toward this option. Minimizing the delay in diagnosis by neonatal screening, together with the availability of prenatal diagnosis may lead to a significant reduction in subsequent births of CF cases.
Attitude to Health↗
[Once more a discussion of the RSV affair].
During autumn- and winter epidemics respiratory syncytial (RS) virus accounts for the majority of respiratory infections in infants and young children. In case of an acute lower respiratory tract infection, RS virus can induce serious symptoms. These are age-dependent. The most important symptoms in babies and toddlers are dyspnea, wheezing, cyanosis and apneas. In the case of respiratory insufficiency or fatigue, as well as recurrent apneas, mechanical ventilation is required. Diagnosis can be made using a direct immunofluorescence technique with monoclonal antibodies. To control the risk of nosocomial RS virus infections, isolation precautions are necessary. The overall mortality is low (less than 1%), but may be strikingly higher in children at risk: babies less than one month of age, preterm babies, infants with congenital heart- or pre-existent respiratory diseases, and those with severe immunodeficiency syndromes. In these subgroups therapy with ribavirin (Virazole) may be beneficial, although until now there is no strong evidence for the effectiveness of this antiviral agent. The majority of the children will have recurrent symptoms of dyspnea and wheezing over the subsequent years following the RS virus infection. In acute lower respiratory RS virus infection, there may be IgE mediated hypersensitivity reactions to viral agents, with release of chemical mediators of airway obstruction. The pathophysiological mechanisms might be comparable to those in patients with asthma.
Child, Preschool↗
[Nocturnal asthma in children, symptoms and treatment].
Nocturnal airflow obstruction is a common symptom in children with asthma. The increase in airflow obstruction overnight is underassessed by children as well as their parents. Worsening of the early morning peak flow values may be an indication for an increase in airflow obstruction overnight. An increase in vagal activity does not, in contrast with the observations in adult patients, contribute to the development of nocturnal airflow obstruction in asthmatic children. However, a nocturnal increase in inflammatory mediators seems to play a role of importance. Treatment of nocturnal airflow obstruction should therefore be focussed on inflammatory processes in the lungs.
Airway Obstruction↗