No description available.

Rings of intrapulmonary bronchi isolated from rabbits producing anti-horseradish peroxidase IgE antibodies contracted when exposed to antigen. The contractile response had a lag period of about 1 min, reached a peak at 6 min and then subsided. Bronchi from rabbits with detectable levels of specific IgG (in addition to IgE) antibodies did not differ in response from those with undetectable specific IgG levels. Histamine also contracted rabbit intrapulmonary bronchi with an EC50 of 10ωM (SD 1.29). The response to antigen was completely inhibited with chlorpheniramine (30 ωM). In contrast to intrapulmonary bronchi, responsiveness of mainstem bronchi to antigen was observed only occasionally, whereas histamine was equipotent on both mainstem and intrapulmonary bronchi. Thus, the amount of antigen-induced mediator release may be less in the mainstem bronchi. Acetyl glyceryl ether phosphorylcholine, in concentrations up to 10 ωM, did not contract either mainstem or intrapulmonary bronchi. This study indicates that histamine is the major mediator of (and acetyl glyceryl ether phosphorylcholine does not significantly participate in) antigen-induced contraction of isolated bronchi from IgE-producing rabbits. The results provide a likely mechanism for the increase in pulmonary resistance observed in IgE anaphylaxis in this species.

Exercise-induced laryngeal obstruction (EILO) is one of many different causes for adolescents to experience dyspnoea during exercise. Objective exercise-testing with continuous video laryngoscopy is crucial for a correct diagnosis since it is difficult to differentiate EILO from other exercise related conditions in the airways only on the symptomatology. The main symptom in EILO is inspiratory stridor arising from an obstruction at the laryngeal level during ongoing exercise which quickly resolves after the exercise has stopped. EILO is often misdiagnosed as exercise-induced bronchoconstriction (EIB), which is obstruction in the peripheral airways that typically arises after cessation of exercise. From a previous survey investigating self-reported exercise-induced dyspnoea in all 12-13-year-old adolescents in Uppsala (n=3,838, response rate 60.2%) a subset of 150 randomly selected adolescents (103 with dyspnoea and 47 controls) performed standardized treadmill exercise-tests for EIB and EILO. During the exercise-test for EIB the subjects breathed dry air according to the current recommended guidelines. EIB was defined as a decrease in FEV1 ≥10% from baseline. EILO was diagnosed during a continuous laryngoscopy exercise (CLE) test by use of the CLE-score method and was defined as an obstruction of grade 2 at either glottic or/and supraglottic laryngeal level. The estimated prevalence of EIB in the general population was 19.2% and the estimated prevalence of EILO was 5.7%. No gender differences were detected. A diagnostic software program for EILO, EILOMEA, was compared with the CLE-score and the methods were found to be compatible. EILOMEA was used to map and compare laryngeal response patterns in adolescents with exercise-induced dyspnoea (EIB and/or EILO), in adolescents with dyspnoea but without a diagnosis of EIB or EILO, and in healthy controls, all of whom had performed the CLE-test. No differences were seen between the healthy controls and the adolescents with dyspnoea without a diagnosis. Only adolescents diagnosed with EILO showed a significant different laryngeal response pattern which strongly suggests that the diagnostic procedure is reliable. In a follow-up study of patients referred for investigation of exercise-induced dyspnoea, we investigated the outcome of surgical vs. conservative treatment of EILO-positive subjects and subjects tested negative for the diagnosis, regarding the level of exercise-induced dyspnoea and physical activity. Surgically treated patients had less breathing problems and were more physically active than both conservatively treated patients and patients who were tested negative.

A alta prevalência de broncoespasmo induzido pelo exercício (BIE) tem sido observada em atletas que praticam modalidades de longa duração. Até o presente momento, nenhum estudo foi realizado no Brasil. Por essa razão, o objetivo deste estudo foi verificar a prevalência de BIE em corredores de longa distância. Para isto, 22 atletas do gênero masculino foram submetidos à prova de função pulmonar, teste de esforço ergoespirométrico e teste de broncoprovocação induzida por hiperpnéia (BIH). Os atletas responderam um questionário sobre sintomas de asma e forneceram informações relacionadas aos seus treinamentos. Após realizarem o teste de BIH, os atletas foram classificados de acordo com a variação do volume expiratório forçado no primeiro segundo (VEF1) em comparação ao valor basal. Aqueles que apresentaram queda do VEF1 igual ou superior a 10% foram denominados Grupo BIE+; os demais foram designados Grupo BIE-. Os resultados demonstraram a presença de BIE em 25% dos atletas. Não foram evidenciadas diferenças estatisticamente significantes em relação às características antropométricas, aos valores basais de função pulmonar, assim como aos parâmetros analisados durante o teste ergoespirométrico. Um aspecto interessante xi observado foi que, os atletas do Grupo BIE+ percorrem, nos seus treinamentos, uma distância inferior quando comparados aos atletas do Grupo BIE- (p≤0,05). Estes resultados sugerem que a presença de BIE pode limitar o rendimento esportivo / The high prevalence of exercise-induced bronchospasm (EIB) has been observed in endurance athletes. Until today, no such study had been conducted in Brazil. The aim of this study was to look for prevalence of EIB among long-distance runners. Twenty-two male athletes were subjected to pulmonary function tests, maximal exercise tests and hyperpnea-induced broncoprovocation (HIB). The athletes also answered questions about asthma symptoms and provided information about their training programs. After the HIB test, they were ranked by the variation in the FEV1 (Forced Expiratory Volume in the first second). Those with a decrease of 10% or more were labeled EIB+ group; all the others were labeled EIB - group. Results show the presence of exercise-induced bronchospasm in 25% of the athletes. Among them, there were no significant statistical differences related to anthropometric characteristics, basal pulmonary function values or other parameters analyzed during the ergospirometric test. One interesting aspect observed was that, in their training sessions, the EIB+ Group athletes ran a shorter distance when compared to those in the EIB- Group (p≤0.05). These results suggest that EIB presence may be a limitting factor in sports performance

Thèses (M.Sc.)--Université de Sherbrooke (Canada), 1998. / Titre de l'écran-titre (visionné le 24 août 2006). Publié aussi en version papier.

A alta prevalência de broncoespasmo induzido pelo exercício (BIE) tem sido observada em atletas que praticam modalidades de longa duração. Até o presente momento, nenhum estudo foi realizado no Brasil. Por essa razão, o objetivo deste estudo foi verificar a prevalência de BIE em corredores de longa distância. Para isto, 22 atletas do gênero masculino foram submetidos à prova de função pulmonar, teste de esforço ergoespirométrico e teste de broncoprovocação induzida por hiperpnéia (BIH). Os atletas responderam um questionário sobre sintomas de asma e forneceram informações relacionadas aos seus treinamentos. Após realizarem o teste de BIH, os atletas foram classificados de acordo com a variação do volume expiratório forçado no primeiro segundo (VEF1) em comparação ao valor basal. Aqueles que apresentaram queda do VEF1 igual ou superior a 10% foram denominados Grupo BIE+; os demais foram designados Grupo BIE-. Os resultados demonstraram a presença de BIE em 25% dos atletas. Não foram evidenciadas diferenças estatisticamente significantes em relação às características antropométricas, aos valores basais de função pulmonar, assim como aos parâmetros analisados durante o teste ergoespirométrico. Um aspecto interessante xi observado foi que, os atletas do Grupo BIE+ percorrem, nos seus treinamentos, uma distância inferior quando comparados aos atletas do Grupo BIE- (p≤0,05). Estes resultados sugerem que a presença de BIE pode limitar o rendimento esportivo / The high prevalence of exercise-induced bronchospasm (EIB) has been observed in endurance athletes. Until today, no such study had been conducted in Brazil. The aim of this study was to look for prevalence of EIB among long-distance runners. Twenty-two male athletes were subjected to pulmonary function tests, maximal exercise tests and hyperpnea-induced broncoprovocation (HIB). The athletes also answered questions about asthma symptoms and provided information about their training programs. After the HIB test, they were ranked by the variation in the FEV1 (Forced Expiratory Volume in the first second). Those with a decrease of 10% or more were labeled EIB+ group; all the others were labeled EIB - group. Results show the presence of exercise-induced bronchospasm in 25% of the athletes. Among them, there were no significant statistical differences related to anthropometric characteristics, basal pulmonary function values or other parameters analyzed during the ergospirometric test. One interesting aspect observed was that, in their training sessions, the EIB+ Group athletes ran a shorter distance when compared to those in the EIB- Group (p≤0.05). These results suggest that EIB presence may be a limitting factor in sports performance

L’arbre bronchique constitue une large interface avec le milieu extérieur ce qui en fait notamment une sentinelle immunologique. Par ailleurs, il est soumis à de multiples contraintes physiques (variation de pressions lors du cycle ventilatoire) avec le développement de pathologies lorsque la réponse à ces contraintes est inadaptée. Au cours de ce travail, nous avons essayé de caractériser la réponse bronchique des voies aériennes distales à partir d’un modèle isolé de bronche humaine soumis à l’application d’un stretch unique ou cyclique tel qu’il est généré lors de la ventilation mécanique. D’un point de vue fonctionnel, le stretch unique ou cyclique s’accompagne d’une modification significative du tonus basal de la bronche avec deux étapes : l’une précoce apparaît au cours de l’exposition même des variations de tension pariétale, l’autre est tardive et apparaît à l’arrêt de l’étirement. Concernant l’étape précoce, elle se révèle robuste car aucun pré-traitement et particulièrement l’abrasion de l’épithélium ne la supprime totalement. La caractérisation de cette réponse implique notamment la voie des NO synthases et des Rho-A kinase. La réponse tardive fait quant à elle intervenir l’épithélium ainsi que la voie des NO-synthase suggérant un rôle prépondérant du NO. Par contre, ces modifications de force au repos sont indépendantes de la sécrétion de médiateurs inflammatoires détectés par ELISA. L’approche génétique renforce par contre le rôle du tissu de soutien bronchique en activant la synthèse de collagène (MMP-9). Au total l'application d'une contrainte cyclique renforce la bronchoconstriction par inhibition de la voie des NOsynthases et de la mécanotransduction. / The tracheo-bronchial tree is a true immunologic sentinel related to the huge interface with the external environment. Moreover, it is submitted to variable physical strains (tidal ventilation and variation in pressure) and an excessive response leads to the genesis of some pathology as hyperresponsiveness. The aim of this work on an isolated organ model was to characterize the human bronchial response to a single or repetitive and physiological stretch as observed during mechanical ventilation. From a functional perspective, a single strain or a cyclic stretch significantly increased the basal tone of the human bronchus with a two-step response: the early response appears during cycling and the delayed after the stretch has ceased. The early response is robust then no pre-treatment and especially epithelial removal totally inhibits it. This response implies NO synthase and Rho-A kinase pathway with a reduction of the developed basal tone with these inhibitors. As it concerns the late response, it involved epithelium and NO synthase suggesting a prominent action of NO. Inflammatory mediators are not directly involved in the rise of basal tone because stretch-induced secretion as detected with ELISA is very low. Genomic approach transiently activates transcription of genes for MMP-9, involved in the collagen production and consequently in the support tissue of the bronchial tree. As a conclusion, cyclic stretch enhances bronchoconstriction by inhibition of the NO-synthase pathway and mechanotransduction.

Experiencing respiratory symptoms in conjunction with exercise is common in children and adolescents and can have a negative impact on daily life. The aim of the thesis was to estimate the prevalence of exercise-induced dyspnoea, exercise-induced bronchoconstriction (EIB) and exercise-induced laryngeal obstruction (E-ILO) in a general adolescent population, and to explore factors associated with EIB. Methods: All 12-13-year-old adolescents in the city of Uppsala (n=3,838) participated in a survey on exercise-induced dyspnoea. A subsample of adolescents who answered the survey, 103 randomly selected adolescents reporting exercise-induced dyspnoea and 47 random adolescents who did not report exercise-induced dyspnoea underwent standardised treadmill exercise tests for EIB and E-ILO. The exercise test for EIB was performed while breathing dry air; a positive test was defined as a decrease ≥10% in FEV1 from baseline. E-ILO was investigated using continuous laryngoscopy during exercise. Health related quality of life (HRQoL), and objectively measured daily physical activity were investigated in those with (n=49) and without (n=91) a positive EIB-test. Results: The prevalence of exercise-induced dyspnoea was 14%, and the estimated prevalence of EIB and E-ILO in the total population was 19.2% and of 5.7%, respectively, with no gender differences. In adolescents with exercise-induced dyspnoea 40% had EIB, 6% had E-ILO, and 5% had both conditions. An increased baseline level of fraction of nitric oxide in exhaled air (FeNO), female gender, and exercise-induced dyspnoea were associated with a positive EIB test. Female adolescents with EIB had lower HRQoL and lower baseline lung function compared to females without EIB. These differences were not observed in male adolescents. There was no difference in time spent in moderate- to vigorous daily physical activity between adolescents with and without EIB.

No description available.

The mismatching of alveolar ventilation and perfusion (VA/Q) is the major determinant of impaired gas exchange. The gold standard for analyzing VA/Q distribution is the multiple inert gas elimination technique (MIGET), conventionally based on gas chromatography (GC), and, although simple in principle, a technically demanding procedure limiting its use. A new technique based on micropore membrane inlet mass spectrometry (MMIMS) combined MIGET with mass spectrometry, simplifying the sample handling process, and potentially providing VA/Q distributions for a general clinical approach. The kinetics of volatile anesthetics are well known in patients with healthy lungs. The uptake and distribution of inhaled anesthetics have usually been modeled by physiologic models. However, these models have limitations, and they do not consider ventilation/perfusion matching. Respiratory diseases account for a large part of morbidity and mortality and are associated with pulmonary VA/Q mismatch that may affect uptake and elimination of volatile anesthetics. The objectives of the studies were firstly to investigate assessment of VA/Q mismatch by MMIMS and secondly to investigate the effects of asthma-like VA/Q mismatch on the kinetics of volatile anesthetics in an experimental porcine model. Anesthetized and mechanically ventilated piglets were studied. In study I, a direct comparison of MIGET by MMIMS with the conventional MIGET by GC in three animal models that covered a wide range of VA/Q distributions was preformed. The two methods agreed well, and parameters derived from both methods showed good agreement with externally measured references. In studies II–IV, a stable method of inducing and maintaining asthma-like VA/Q mismatch with methacholine (MCh) administration was established, and the effect of VA/Q mismatch on the pharmacokinetics of desflurane and isoflurane was investigated. The present model of bronchoconstriction demonstrates a delay in volatile anesthetic uptake and elimination, related to the heterogeneity of MCh-inhalation induced ventilation. The difference in solubility of volatile anesthetics has a significant influence on their uptake and elimination under VA/Q mismatch. The higher blood soluble isoflurane is affected to a lesser degree than the fairly insoluble desflurane.