Objective To investigate the changes of small airway function and diffusing capacity in patients with mild asthma before and after bronchial provocation test (BPT).Methods BPT was performed in suspected asthma patients with chief complaints of paroxysmal wheeze,chest tightness and cough，but with normal chest X-ray and baseline pulmonary function.BPT positive group was regarded as asthma group，while BPT negative group as control group.Lung volume，ventilatory function and diffusing capacity were measured before and after BPT and compared between the asthma and control groups.Results （A）No statistical differences were found in FEV1%，FEV1/FVC，FVC%，VC%，TLC%，FRC%，RV%，RV/TLC between the asthma and control groups before BPT.FEV1/FVC and FVC% were significantly decreased (all Plt;0.01)，while FRC% (Plt;0.05)，RV% (Plt;0.01) and RV/TLC (Plt;0.01) increased significantly in the asthma group after BPT compared with the control group.The decline rate of FEV1/FVC and FVC% and the increase rate of TLC%，RV%，RV/TLC were significantly higher in the asthma group than those in the control group (all Plt;0.01).（B）Compared with the control group，FEF25%-75% (Plt;0.05)，Vmax75% (Plt;0.01) and Vmax50% (Plt;0.05) were significantly lowered before BPT，while the above parameters and Vmax25% were significantly decreased after BPT in the asthma group (all Plt;0.01).The decline rate of FEF25%-75%，Vmax75%，Vmax50% and Vmax25% was significantly higher in the asthma group than those in the control group (all Plt;0.01).（C）There was no statistical difference in DLCO in both groups before and after BPT.Conclusions Patients with mild asthma had small airways impairment before BCT which further declined after BPT.However,no impairment of diffusion capacity was found before or after BPT.
Objective To investigate the relationship of small airway function with airway sensitivity and reactivity and assess the factors influencingairway hyperresponsiveness (AHR).Methods Data of consecutive subjects with suspected asthma who had a≥20% reduction in FEV1 after ≤12.8 mmol/L cumulative doses of methacholine were analyzed from January 2005 to April 2006.Airway sensitivity was assessed by the cumulative dose of methacholine required to cause 20% reduction in FEV1 (PD20).Airway reactivity was analyzed using the slope of the dose-response curve (DRS).The DRS was defined as the reduction in FEV1 from baseline after the final dose of methacholine inhaled divided by the cumulative dose inhaled.Because of their highly skewed distribution，DRS was logarithmically transformed (log10) for all analysis.Results A total of 184 consecutive subjects aged 16 to 80 years was enrolled.There were 70 male (38.0%) and 114 female (62.0%) subjects.Subjects with higher airway sensitivity，indicated by lower PD20，also had a lower Vmax50% and Vmax25%，and vise versa.PD20 was negatively correlated wit log10DRS (r=-0.874，Plt;0.01).In a simple linear regression model，log10DNS was significantly correlated with FEV1%，Vmax50% or Vmax25% respectively (the determinant r2 were 0.062，0.097 and 0.085，respectively，all Plt;0.01).In a multiple linear regression model that included age，height，and percentage of predicted FEV1，Vmax50% and Vmax25% accounted for 3.9% and 2.6%，respectively，of variability in airway reactivity.The association between Vmax50% and log10DNS was significant in both male and female subjects.The r2 was higher in male subjects.The subjects were divided into three age groups and the association between Vmax50% or Vmax25% and log10DNS was higher in female than in male for age≤25 years，higher in male than in female for 25 -45 years.No association was found for agegt;45 years in both males and females.Conclusions Impaired small airway function is associated with higher airway sensitivity and reactivity to methacholine in subjects with suspected asthma.
Objective To explore the distribution of bacteria among community acquired lower respiratory tract infection (LRTI) inpatients with underlying chronic respiratory tract diseases.Methods The clinical data，sputum culture and drug susceptibility results of 212 community acquired LRTI patients who were hospitalized during the period 2001-2005 were retrospectively analyzed.All patients had various underlying chronic respiratory tract diseases.Results A total of 229 strains of pathogens were detected，with the majority being gram negative bacteria.In pathogens of acute exacerbation of chronic obstructive pulmonary disease，gram negative bacteria occupied 73.9%.And Pseudomonas aeruginosa and Klebsiella pneumoniae were the most common pathogens，with each occupying 18.2% and 13.6% respectively.Gram positive bacteria occupied 23.8%，mainly Staphylococcus aureus (10.2%) and Streptococcus pneumoniae (9.1%).In patients with bronchiectasis exacerbated by bacterial infection，86.2% were caused by gram negative bacteria，the top three being，in descending order，Pseudomonas aeruginosa (27.5%)，Haemophilus parainfluenzae (13.7%)，and Haemophilus influenzae (11.8%).Bronchiectasis was the major risk factor of getting Pseudomonas aeruginosa infection (OR=5.590，95%CI 2.792~11.192).The risk factors of getting Acinetobacter baumanii infection were antacid usage within 1 month (OR=9.652，95%CI 2.792~11.192) and hypoalbuminemia (OR=2.679，95%CI 1.108~6.476).For enterobacters infections，including Klebsiella pneumoniae，Enterobacter cloacae and Escherichia coli，the risk factors were antibiotic usage within 1 month (OR=4.236，95%CI 1.982~9.057)，having renal diseases (OR=4.305，95%CI 1.090~17.008) and diabetes mellitus (OR=2.836，95%CI 1.339~6.009).Conclusions Gram negative bacteria were the main pathogens of community acquired LRTI in hospitalized patients with underlying chronic respiratory tract diseases.The pathogens were influenced by underlying diseases，severity of diseases and drug usage history of patients.
Objective To investigate the role of urotensin Ⅱ(UⅡ) in the pathogenesis of asthma.Methods Lung function，differential cell count and level of UⅡin induced sputum were studied in 26 asthmatic patients in acute exacerbation and in clinical remission.Results Induced sputum UⅡ level from acute asthma was higher than that of remissed asthma [(58.88±47.38)pg/mL vs (12.69±12.78)pg/mL，Plt;0.01].Induced sputum UⅡ levels of asthma patients in acute exacerbation had a tendency to increase as disease deteriorated，which negatively correlated with FEV1% predicted (r=-0.326，Plt;0.05)，but did not with sputum total cell and neutrophil counts(Pgt;0.05).No significant difference of induced sputum UⅡ levels was found between male and female，smokers and non-smokers.Conclusion UⅡ may play a role in acute exacerbation of asthma
Objective To investigate the role of endogenous Hydrogen Sulfide ( H2S) in airway inflammation and responsiveness in a rat model of chronic passive-smoking. Methods Male SD rats were randomly divided into a control group ( breathing fresh air) and a passive smoking group [ cigarette smoking( CS) passively] , with 18 rats in each group. Six rats in each group were randomly intraperitoneally injected with normal saline, sodium hydrosulfide ( NaHS) or propargylglycine ( PPG, an irreversible inhibitor of cystathionine- γ-lyase) . The animals were divided into six subgroups, ie. Con group, NaHS group, and PPG group, CS group, CS+ NaHS group, and CS + PPG group. After 4 months, lung histological change and airway tension were measured. The H2S levels of plasma and lung tissue were analyzed by the sensitive sulphur electrode assay. The expression of cystathionine-γ-lyase ( CSE) was measured by western blot. Results Compared with the Con group, CSE protein expression in lung tissues was increased in CS group( P lt;0. 05) ; the H2 S levels of plasma were significantly higher in CS group, NaHS group and CS + NaHS group, and much lower in PPG group ( P lt; 0. 05, respectively) . Compared with CS group, the H2S levels of plasma were significantly higher in CS + NaHS group, and much lower in CS + PPG group( P lt; 0. 05, respectively) . The H2S level of lung tissue in each group had no significant difference ( P gt; 0. 05) . Compared with Con group,score of lung pathology was significant elevated, and the responsiveness of airway smooth muscles to ACh and KCl was significant augmented in CS group. Compared with CS group, the score of lung pathology was decreased, and the responsiveness of airway smooth muscles was decreased in CS +NaHS group( P lt;0. 05) , and vise versa in CS + PPG group( P lt; 0. 01) . Conclusion H2S can alleviate airway inflammation and hyperresponsiveness induced by CS, and administration of H2S might be of clinical benefit in airwayinflammation and airway responsiveness.
【Abstract】Objective To investigate the contribution of occupational exposure to dusts / gases / fumes to chronic obstructive pulmonary disease( COPD) and respiratory symptoms in China. Methods Based on the crosssectional survey of COPD which was conducted in urban and rural areas of Beijing, Shanghai, Guangdong,Liaoning, Tianjin, Chongqing and Shanxi for residents aged 40 years or older, the association between the occupational exposure to dusts/ gases/ fumes and COPD and respiratory symptoms was analyzed. The recruited populations were interviewed with questionnaire and were tested with spirometry. The post-bronchodilators FEV1 /FVC lt; 70% was used as diagnostic criteria of COPD. Having any cough, sputum, wheezing and dyspnea was defined as having respiratory symptoms. Results The prevalence of occupational exposure to dusts/ gases /fumes was 20. 5% . As shown by multiple-variables Logistic regression analyses, occupational exposure to dusts / fumes /gases [ OR = 1. 20 ( 1. 04, 1. 39) ] and dusts of grain [ 1. 48 ( 1. 18, 1. 86) ] were associated with COPD;occupational exposure to dusts / fumes / gases [ OR = 1. 37( 1. 25, 1. 49) ] , hard-rock mining [ OR = 2. 31( 1. 67,3. 20) ] , coal mining [ OR = 1. 71( 1. 09, 2. 70) ] , dusts of cement [ OR = 1. 92( 1. 47, 2. 52) ] , chemical or plastics manufacturing [ OR =1. 58( 1. 37, 1. 83) ] , spray painting [ OR= 1. 46( 1. 16, 1. 84) ] , and other dusts or fumes [ OR = 1. 46 ( 1. 29, 1. 64 ) ] were associated with the respiratory symptoms. Smoking and occupational exposure to dusts / gases / fumes had synergic effects on the increasing risk of respiratory symptoms. The populationattributable risk ( PAR) of exposure to dusts / gases / fumes was 3. 94% and 7. 05% for COPD and respiratory symptoms respectively. Conclusions Occupational exposure to dusts /gases /fumes is associated with COPD and respiratory symptoms. Smoking and occupational exposure to dusts/ gases /fumes may have synergic effects on respiratory symptoms.