| Summary: | 碩士 === 國立臺灣大學 === 環境衛生研究所 === 92 === Analysis of exhaled breath condensate (EBC) components for diagnostic purpose has received attention in recent years because the sampling method is very simple and noninvasive. For example, several studies measured small molecules in EBC (H2O2, 8-isoprostane, and NO-derived products, etc.) to correlate with oxidative stress or disease in pulmonary system. None of the EBC sampling and analysis methods in current literatures has detailed description about how they control their data measurement quality however, thus makes the comparison of their results relatively difficult.
This study aimed at improving the EBC-reactive oxygen species (EBC-ROS) collection and analysis method, and investigating factors that might influence the quality of the data measurement. The method then was used to measure and compare the EBC-ROS concentration in nonsmokers and smokers.
An improved EBC collecting system was used to collect EBC, and the ROS concentration in EBC was measured using a DCFH2-HRP chemical fluorescent method. For EBC collection, a simple impinger type saliva trapping device was connected to the front end of the EBC collecting tubing, this device can effectively prevent the pollution of EBC by saliva. To measure exhaled air volume of each EBC sample collected accurately, a dry test gas meter was added at the end of the EBC collecting device. Both these modification greatly improved data quality, and the duplicate sample analysis indicated less than 10% variation can be obtained.
In addition to the basic QA/QC tests, factors including sampling volume and the sampling time within a day were also examined for their effect on the ROS concentration measurement. No difference was observed in ROS concentration in EBC collected either using 60 or 40 liters of exhaled air. The mean EBC-ROS concentration was significantly higher at 18:00 than at 10:30, 12:00, and 15:00. This within-day variation at late afternoon may be either due to the test subjects’ one-day activities or due to the whole day’s exposure of pollutants.
Smokers immediately after smoking showed a significant increase in EBC-ROS concentration as comparing with before smoking, but no difference after half an hour of stop smoking. EBC collected from eight current light smokers and eighteen non-smokers have similar ROS concentration levels, except one who has the habit of betel nut chewing, this should worth further study.
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