Objective To develope a novel rabbit carotid body and carotid common artery model in vivo for the simulation of various intermittent hypoxia ( IH) intensities, IH durations, IH reoxygenation ( ROX) durations and continuous hypoxia ( CH) modes. Methods Forty-five adult New Zealand rabbits ( 2. 5-3. 0 kg) were anesthetized while spontaneous breathing kept intact. The tissue surrounding the right carotid common artery and carotid sinus nerve ( CSN) were cleared and " single" chemoreceptor bundle of the CSN was revealed. Then suction electrodes were placed and CSN afferent activity was monitored and recorded carefully. The right common carotid artery was exposed, cannulated to distal part and its proximal part was ligated. Preparations were challenged by changing the PO2 of the gas mixture equilibrating the perfusate. Alternatively perfusion ( 2 mL/min) of equilibrated perfusate bubbled with normoxia or hypoxia gas mixtures formed IH/ROX cycles in carotid common artery, simulating the pattern of hypoxic episodes seen in obstructive sleep apnea syndrome ( OSAS) , or with continuously perfusing hypoxia perfusate to form CH modes. All the perfusing procedures were regulated by a customized computer-controlled set and monitored using O2 gas analyzer. After the systematic exposures, carotid body, carotid common artery part distal to cannula, and carotid bifurcation were harvested as samples. Results The frequencies and average amplitudes of CSN chemoreceptor bundles afferent activities with normoxia perfusion were ( 0. 17 ±0. 03) impulse/ s and ( 46. 2 ±4. 4) μV, and with hypoxia perfusion were ( 0. 64 ±0. 09) impulse/ s and ( 87. 4 ±6. 6) μV, respectively. PO2 was ( 139 ±1. 5) mm Hg in normoxia perfusate and ( 35. 2 ±1. 3) mm Hg in hypoxia perfusate. Conclusion This new carotid body and carotid common arterymodel is a valuable tool to study neurological and biochemical changes in various IH and CH modes.
【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.