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  • 1
    ISSN: 1432-1440
    Keywords: Exercise induced asthma ; Allergic asthma ; Histamine ; Catecholamines ; Theophylline ; Plasma levels ; Anstrengungsasthma ; allergisch-bedingtes Asthma ; Histamin ; Katecholamine ; Theophyllin ; Plasmaspiegel
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Um zu untersuchen, ob endogene Transmitter bei der Auslösung und Unterhaltung verschiedener Formen des Asthma bronchiale eine Rolle spielen, haben wir bei Kindern vor und nach einer Laufbelastung sowie vor und nach einer inhalativen Provokation mit wäßrigen Allergenextrakten das Serumhistamin, Serumnoradrenalin und den bronchialen Strömungswiderstand (Rt) bestimmt. Die Untersuchung zeigt, daß das Belastungsasthma mit einem starken Anstieg des Plasmanoradrenalins, nicht jedoch des Plasmahistamins einhergeht. Dieser Anstieg war wesentlich ausgeprägter als der bei einem asthmatischen Vergleichskollektiv ohne Anstrengungsasthma. Im Gegensatz dazu zeigten die Kinder, die nach einer Allergenprovokation einen Asthmaanfall entwickelten, einen signifikanten Histamin-, jedoch keinen Noradrenalinanstieg. Zwischen Histamin-Serumspiegel und Stärke der Bronchokonstriktion bestand eine gute Korrelation (r=0.98). Nach oraler Applikation übte Theophyllin einen Schutz sowohl gegenüber dem Anstrengungsasthma, als auch gegenüber dem allergisch bedingten Asthma aus. Da Theophyllin beim allergisch ausgelösten Asthma nicht nur zu einem Abfall von Rt führte, sondern auch den Histaminanstieg verminderte, kann vermutet werden, daß ein Teil der Wirkung dieser Substanz beim allergischen Asthma auf einer Hemmung der Histaminfreisetzung beruht. Die Noradrenalinfreisetzung beim Anstrengungsasthma beeinflußte es nicht. Für seine protektive Wirkung bei dieser Asthmaform müssen daher andere Wirkungsmechanismen angenommen werden. Ob diese ausschließlich auf einer Relaxation beruhen, muß ungeklärt bleiben. Als Schlußfolgerung dieser Untersuchung wird deutlich, daß das Anstrengungsasthma und das allergische Asthma 2 verschiedene Typen eines Syndroms sind. Arzneimittel, die gegenüber beiden Typen wirksam sind, können dies über verschiedene Wirkungsmechanismen tun.
    Notes: Summary To investigate whether endogenous transmitters play a role in different forms of bronchial asthma we determined histamine and noradrenaline plasma levels as well as airway resistance (Rt) before and after exercise and allergen challenge in children. The study demonstrates that in exercise induced asthma (EIA) broncho-constriction was paralleled by increases of noradrenaline, but not of histamine plasma levels. This increase of noradrenaline was much more pronounced than that observed in the asthmatic control group not suffering from EIA. In contrast to what has been observed in EIA, bronchoconstriction in response to allergen challenge was closely associated with increases of histamine, but not of noradrenaline plasma levels. Between histamine concentrations and severity of illness a good correlation was found (r=0.98). Tests carried out after oral administration of theophylline showed a protection against EIAand allergic induced asthma. Since theophylline in allergic asthma concomitantly reduced the increase in Rt and plasma histamine it is suggested that at least part of the beneficial effects of theophylline in allergic asthma may result from inhibition of histamine release. In those children suffering from EIA theophylline did not affect noradrenaline release. Thus, consideration must be given to effects of theophylline against EIA which are based on other mechanisms. Whether these effects are solely attributable to relaxation of bronchial smooth muscle or not remains to be clarified. In conclusion this study clearly has identified exercise and allergic induced asthma as different types of the syndrome that we call asthma. Drugs which prevent against both types may do this by different modes of action.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    European journal of pediatrics 134 (1980), S. 45-50 
    ISSN: 1432-1076
    Keywords: Exercise induced asthma (EIA) ; Catecholamines ; Cyclic AMP ; a-Adrenergic blockade ; Allergic asthma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In order to provoke exercise induced asthma (EIA) a test which involved running for 7 min was performed with 21 asthmatic children. Eleven children not only developed a highly significant increase in airway resistance (Rt), but showed also a 4-fold increase in plasma noradrenaline (NA) levels. In 10 children who did not develop EIA only a 1.5-fold increase of NA could be observed. Following exercise cyclic AMP showed an identical increase in both groups studied, whereas adrenaline levels remained uninfluenced. Tests carried out after administration of phentolamine by inhalation showed a significant inhibition of post-exercise bronchoconstriction. It is concluded that EIA originates from a-receptor stimulation which is mediated by excessive noradrenaline release. However, since disodium cromoglycate—which does not act via adrenergic mechanisms—also protected against EIA, other factors should be involved. In 5 children with allergic asthma, asthmatic attacks were accompanied by a significant decrease in cAMP, whereas noradrenaline levels remained uninfluenced. Thus, evidence appears that both types of asthma result from different autonomic dysfunctions.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    European journal of pediatrics 147 (1988), S. 121-122 
    ISSN: 1432-1076
    Keywords: α-Adrenoceptors ; β-Adrenoceptors ; Phaeochromocytoma ; Catecholamines ; Desensitization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A 16-year-old boy is described who had a relapse of a phaeochromocytoma 6 years after an initially successful tumour resection. The relapse was suspected after routine testing of urinary catecholamine excretion and was confirmed by scintigraphy with 123I-meta-iodobenzylguanidine, computed tomography and magnetic resonance imaging. The plasma norepinephrine level was 3082 pg/ml (normal 〈500 pg/ml); the plasma epinephrine level was in the normal range. Surprisingly, our patient had no symptoms, including hypertension. The density of the α- and β-adrenoceptors on circulating blood cells was decreased. Postoperatively the plasma catecholamine levels were in the normal range. Three months after surgery the adrenoceptor density was almost normal. We conclude that the absence of clinical symptoms was probably due to desensitization of the adrenoceptors. After a successful operation to treat phaeochromocytoma, long-term monitoring of catecholamines is necessary to rule out an asymptomatic relapse.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-1076
    Keywords: β-adrenoceptors ; Down-regulation ; Catecholamines ; Congenital heart disease
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Twenty-six infants and children with congenital heart disease (CHD) undergoing cardiac surgery were investigated for alterations in myocardial β-adrenoceptor density. The patients were divided into three groups according to type and severity of CHD: group I consisted of 6 patients with acyanotic shunt lesions of moderate severity; group II comprised 13 children with severe acyanotic shunt and valve lesions and group III included 7 children with cyanotic CHD. The myocardial β-adrenoceptor density was determined using (−)3-[125I] Iodocyanopindolol ([125I]ICYP) and was reduced by approximately 50% in severe acyanotic CHD (33.6 fmol/mg protein) and cyanotic CHD (35.3 fmol/mg protein) in comparison with the group with less severe acyanotic shunt defects (64.4 fmol/mg protein). The affinity dissociation constant (K d, ICYP) did not differ statistically between the groups. The proportion of β1- and β1-subpopulation was evaluated by ICI 118,551-[125I]ICYP competition studies. In group II (61.5%) and group III (69.1%) significant lower portions of β1-adrenoceptors were found compared with group I (78.2%). This shift of subpopulations was due to a decreased β1-receptor density while β2-receptor density was unchanged in all groups. While the plasma noradrenaline levels of group I were similar to those of a control group of 13 healthy children, respective values of group II and III were significantly elevated. A significant negative correlation was found between plasma noradrenaline levels and myocardial β-adrenoceptor density. It is concluded that exposure of these receptors to increased circulating catecholamines, due to an enhanced sympathetic tone, leads to a reduction of their density. Noradrenaline, a preferential agonist of β1-adrenoceptors, is most probably responsible for the shift of the β-adrenoceptor subpopulations from the β1- to β2-subtype, depending on severity and type of cardiac disease.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-1440
    Keywords: Β-Adrenoceptors ; Mononuclear leukocytes ; Right atrium ; Down-regulation ; Catecholamines ; Congenital heart disease
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Sympathetic regulation of myocardial performance has been shown to be altered in congestive heart failure. Right atrial tissue of children with severe acyanotic and cyanotic congenital heart disease (CHD) showed a significantly lowerΒ-receptor density than that of children with less severe defects. Since mononuclear leukocytes (MNL) contain a homogeneous population ofΒ 2-adrenoceptors which have similar properties to those of cardiacΒ 2-adrenoceptors, they are frequently used for studying theΒ-adrenergic system. In a group of 37 children with CHD of different types and severity who underwent cardiac surgery, we compared the MNLΒ-adrenoceptor density to the type and severity of CHD and looked for a possible relationship to plasma catecholamine levels and to the right atrialΒ-adrenoceptor density. Membranes of MNL and myocardial cells were radiolabeled with (−)3-[125I]Iodocyanopindolol ([125I]ICYP). A significantly higherΒ-adrenoceptor density on MNL was found in patients with moderate acyanotic CHD (group I) than in those with severe acyanotic (group II) and cyanotic CHD (group III). Patients of group I showed approximatively 50% higher myocardialΒ-receptor density than those of groups II and III. ICI 118.551-[125I]ICYP competition studies revealed that in groups II and III significantly lower proportions and densities ofΒ 1-receptors were found compared to group I. Noradrenaline (NA) plasma levels in group II and group III were significantly higher than those in group I. The adrenaline plasma levels were found to be very high in all children with CHD. A significant negative correlation between NA levels and myocardial total andΒ 1-adrenoceptor density, but no correlation between plasma catecholamines and MNLΒ-adrenoceptor density, was calculated. We conclude that modulation of MNLΒ-adrenoceptors is not simply controlled by circulating catecholamine levels. CardiacΒ 2-adrenoceptor density remained unaltered, but theΒ 1-density was significantly lowered.Β 2-adrenoceptors on MNL showed a slight but significant decrease. However, cardiacΒ 2-adrenoceptor density cannot be predicted by measuring theΒ-adrenoceptor density on MNL.
    Type of Medium: Electronic Resource
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