• Tuberculosis and Respiratory Diseases
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• v.42 no.2
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• pp.165-174
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• 1995

Background: Exercise is one of the most common precipitants of acute asthma encountered in clinical practice. The development of airflow limitation that occurs several minutes after vigorous exercise, i. g. exercise-induced bronchoconstriction(EIB), has been shown to be closely correlated with the nonspecific bronchial hyperresponsiveness, which is the hallmark of bronchial asthma. All previous reports that assessed the correlation of EIB to nonspecific bronchial hyperresponsiveness have focused on airway sensitivity($PC_{20}$) to inhaled bronchoconstrictor such as methacholine or histamine. However, maximal airway narrowing(MAN), reflecting the extent to which the airways can narrow, when being exposed to high dose of inhaled stimuli, has not been studied in relation to the degree of EIB. Methods: Fifty-six children with mild asthma(41 boys and 15 girls), aged 6 to 15 years(mean${\pm}$SD, $9.9{\pm}2.5$ years) completed this study. Subjects attended the laboratory on two consecutive days. Each subject performed the high-dose methacholine inhalation test at 4 p.m. on the first day. The dose-response curves were characterized by their position($PC_{20}$) and MAN, which was defined as maximal response plateau(MRP: when two or three data points of the highest concentrations fell within a 5% response range) or the last of the data points(when a plateau could not be measured). On the next day, exercise challenge, free running outdoors for ten minutes, was performed at 9 a.m.. $FEV_1$ was measured at graduated intervals, 3 to 10 minutes apart, until 60 minutes after exercise. Response(the maximal ${\triangle}FEV_1$ from the pre-exercise value) was classified arbitrarily into three groups; no response((-) EIB: ${\triangle}FEV_1$<10%), equivocal response ($({\pm})$EIB:10%<${\triangle}FEV_1$<20%) and definite response($({\pm})$EIB:${\triangle}FEV_1$>20%). Results: 1) When geometric mean $PC_{20}$ of the three groups were compared, $PC_{20}$ of (+) EIB group was significantly lower than that of (-)EIB group. 2) There was a close correlation between $PC_{20}$ and the severity of EIB in the whole group(r=-0.568, p<0.01). 3) Of the total 56 subjects, MRP could be measured in 36 subjects, and the MRP of these subjects correlated fairly with the severity of EIB(r=0.355, p<0.05) 4) The MAN of (+) EIB group was significantly higher than that of (-)EIB group(p<0.01). 5) The MAN correlated well with the severity of EIB in the whole group(r=0.546, p<0.01). Conclusion: The degree of MAN as well as bronchial sensitivity($PC_{20}$) to methacholine is correlated well with the severity of EIB. The results suggest that the two main components of airway hyperresponsiveness may be equally important determinants of exercise reactivity, although the mechanism may be different from each other. The present study also provides further evidence that EIB is a manifestation of the increased airway reactivity characteristic of bronchial asthma.

• Journal of Life Science
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• v.17 no.8 s.88
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• pp.1166-1171
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• 2007

Exercise is the strongest stress to which the body is ever exposed. The body responds to this stress through a set of physiological changes in its metabolic, hormonal, and immunological systems. In this study, responses of the immune system to the long-term aerobic and anaerobic exercises have been investigated. Regular moderate exercise is associated with a reduced incidence of infection compared with a sedentary groups. Aerobic training increases the heart rate and enhances the body's intake of oxygen long enough to benefit the condition of the body. In recent years, the importance of exercise in everyday life has been rapidly increasing. Moderate exercise appears to stimulate the immune system. And also, Exercise elicits an increase in the numbers of circulating lymphocytes and lymphocyte subsets (including NK cells) which is followed by a decrease in the numbers of cells during recovery from exercise. However, prolonged bouts of strenuous exercise cause a temporary depression of various aspects of immune functions (e.g. lymphocyte proliferation, monocyte antigen presentation, open window periods, exercise induced asthma, exercise induced anaphylaxis) that usually lasts 2-24 hr after exercise depending on the intensity and duration of the exercise bout. Exercise-induced bronchoconstriction (EIB) was defined as a decrease of at least 15% in pre exercise forced expiratory volume in one second at any time point after exercise. This includes elevation of cortisol and cathecholamines in plasma. On the other hand, highly trained athletes exhibit a chronic mild hypercortisolism at baseline that maybe an adaptive change to chronic exercise. And, Consuming carbohydrate during prolonged strenuous exercise attenuates rises in stress hormones and appears to limit the degree of exercise-induced immune depression. Recent evidence suggests that antioxidant vitamin supplementation may also reduce exercise stress and impairment of leukocyte functions.

• Tuberculosis and Respiratory Diseases
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• v.48 no.2
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• pp.203-209
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• 2000

Background: Exercise is a very common precipitant of asthma. Bronche-constriction associated with exercise can occur in 75~90% of individuals with asthma The estimated prevalence(30~85%) of gastroesophageal reflux(GER) in patients with asthma is significantly higher than in general population. We performed pH monitoring during the exercise in order to evaluate whether exercise induced asthma(EIA) could be related to GER and acid reflux-induced esophagobronchial reflex-mediated bronchospasm might be a factor for EIA. Method: Following an overnight fast, 18 patients with a suspected EIA(6 men, 12 women) were studied. Monitoring of intraesophageal pH, ECG and spirometry was done for 1 hour before treadmill exercise. After baseline monitoring, subjects underwent symptom-limited treadmill exercise with Bruce protocol and continuous monitoring for 60 min after exercise. Spirometry was done at baseline prior to exercise, and repeated every 10 min after full exercise for 60 min. Results: Exercise-induced bronchoconstriction was noted in 15 patients, who performed MBPT and 12 patients confirmed for bronchial asthma and 3 patients were diagnosed exercise-induced astham. Five of 15 EIA patients demonstrated a pathologic degree of GER. Conclusion: We suggest that GER may be one of pathophysiologic factors of EIA and evoke further concentration on the GER in the EIA patients.

• Clinical and Experimental Pediatrics
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• v.48 no.8
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• pp.881-885
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• 2005

Purpose : Airway dehydration and subsequent hyperosmolarity of periciliary fluid are considered critical events in exercise-induced bronchoconstriction. The aim of this study was to establish if a hyperosmolar challenge could induce activation of eosinophils. Methods : Human eosinophilic leukaemic cell lines, EoL-1 cells were incubated with hyperosmolar solutions for 15 minutes. Activation of EoL-1 cells was monitored by degranulation and superoxide anion production. In addition, we examined surface expression of CD69 and ICAM-1. Results : Hyperosmolar stimuli didn't induce superoxide anion production and degranulation. In addition, EoL-1 cells cultured with hyperosmolar medium at 930 mOsm/kg $H_2O$ resulted in no significant increment in fluorescent intensity of CD69 and ICAM-1 expression compared with results for cells incubated with isomolar medium. Conclusion : We found that hyperosmolar stimuli don't cause activation of EoL-1 cells, but further studies are required to determine the role of eosinophil in the mechanism of exercise-induced asthma.

• Tuberculosis and Respiratory Diseases
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• v.45 no.6
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• pp.1188-1198
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• 1998

Background : The purpose of the present study was to determine the protective effect of antiasthmatic activity of inhaled heparin, cromolyn sodium, budesonide, furosemide in exercise-induced asthma(EIA). The other important considerable point of this study was the mechanism of bronchoconstriction on EIA. Methods : Eight subjects with a history of EIA were studied on 5 different experiment days. After obtaining baseline $FEV_1$ and FVC, subjects performed a standardized exercise challenge. EIA was assessed by measurement of $FEV_1$ before and after exercise. On experiment day 4, the exercise challenge was performed after the subjects inhaled either heparin (1,000 units/kg/day for 5 days), furosemide (1mg/kg for 5 days), cromolyn (4mg/day for 5 days), or budesonide ($400{\mu}g/day$ for 5 days). On experiment day 5, the methacholine bronchial provocation test was performed. On experiment day 3, activated partial thromboplastine time(aPTI) was checked. Results : Maximum decrements of $FEV_1$ (mean${\pm}$SE) among 0 to 120 minutes after exercise were as follows : heparin was $83.1{\pm}4.81%$ (p=0.010), furosemide was $80.5{\pm}6.87%$ (p=0.071), cromolyn was $86.8{\pm}6.53%$ (p=0.340), and budesonide was $79.4{\pm}7.31%$ (p=0.095). Above medications were compared to the control value ($72.5{\pm}18.2%$) by paired t-test. No medications had effect on $PD_{20}$ of methacholine bronchial provocation test The results were control $1.58{\pm}0.49{\mu}mol$), heparin ($4.17{\pm}1.96{\mu}mol$), furosemide ($1.85{\pm}0.86{\mu}mol$), cromolyn ($2.19{\pm}0.89{\mu}mol$), and budesonide ($3.38{\pm}1.77{\mu}mol$), respectively(p>0.05). The inhaled heparin had no effect of anticoagulation. Conclusion : These data demonstrate that inhaled heparin has a protective effect on EIA. The effect of inhaled cromolyn was statistically absent with manufacture's recommended dosage on EIA. So, the dosage of cromolyn should be carefully evaluated in future. Although inhalation of budesonide and furosemide have no statistical significance compared to control, these drugs also have some protective effects on EIA.