| Summary: | 碩士 === 國立成功大學 === 環境醫學研究所 === 88 === Previous reports have suggested that endotoxin can be strongly associated with COPD (Chronic Obstructive Pulmonary Disease), and exposure to environmental endotoxin is thought to cause various health problems such as irritation of the eye, fever, diarrhea, respiratory symptoms, SBS, and inflammatory reactions. One investigation has found a decrease in lung function with exposure to endotoxin ranging between 0.2-470 ng/m3. It becomes essential to obtain the actual levels of environmental endotoxin to design the preventive measures for assuring public health. The conventional method for analyzing endotoxin is the Limulus Amoebocytes Lysates (LAL) test. Although this method is sensitive, several substances can also activate or inhibit the enzyme, which then influences the results. In addition, the study on the chemical constitute of endotoxin is also inevitably important to verify the exact relationship between endotoxin and its biological effects. The present study is therefore set to examine the distribution and amount of dominant chemical makers in environmental endotoxin and possibly their corresponding health impacts.
Environmental samples were collected from houses of asthmatic children in Tainan City, landfill sites, office buildings and grain storage rooms. Analyzing concurrently with LAL test and GC-MS method, we hope to establish from these samples the distribution of 3-hydroxy fatty acids and the association between 3-hydroxy fatty acids and potency of endotoxin in various environments.
In house dust, the total endotoxin concentration analyzed by LAL test is in the range of 4.05-152 ng/mg, mostly around 50 ng/mg, and in the range of 30.62-1158.10 Eu/mg in potency. The total amount and potency of endotoxin show no significant difference when compared between two seasons. GC-MS analyses indicate that the dominant fatty acids in this environment are possibly 3-hydroxy fatty acid C14, 3-hydroxy fatty acid C16, and 3-hydroxy fatty acid C18. The total amount of endotoxin calculated based on the composition of fatty acids suggests that individual concentration is not more than 20 ng/mg, and in the range of 83.9-1422.91 ng/mg. There is no correction between LAL test and GC-MS or individual fatty acids in this environment.
In grain rooms, the total endotoxin is between 0.069-0.523 ng/m3 and 0.530-1.440 ng/m3 by LAL test and GC-MS, respectively. The characteristic fatty acids in this environment are possibly 3-hydroxy fatty acid C10, 3-hydroxy fatty acid C14, and 3-hydroxy fatty acid C18, consistent with the previous study. We expect that the dominant bacterial species are Enterobacter agglomerans, seudomonas spp., Serratia spp., and Acinetobacter spp. There is no correction between results of these two methods. However, a significant correlation can be found in samples showing high concentrations of endotoxin, and the amount and potency may be attributed to mainly 3-hydroxy fatty acid C10 and3-hydroxy fatty acid C14 as relationship appears to be built between the LAL test results and these two chemical makers.
In office buildings, the total amount of endotoxin is between 9.38-43.00 ng/mg and 51.22-976.61 ng/mg in dust samples by LAL test and GC-MS, respectively. The total amount of endotoxin is 0.0005-0.0440 ng/m3 and 0.0049-0.0574 ng/m3 in airborne samples, also by LAL test and GC-MS respectively. The main fatty acids in this environment are 3-hydroxy fatty acid C16 and 3-hydroxy fatty acid C18 and in dust samples.
In samples of landfill sites, the levels of endotoxin are in the range of 0.0001-0.0031 ng/m3 and 0.0287-0.1039 ng/m3 by two methods. In addition, the samples from the Fall have built a relationship between the methods, which is not found in winter samples.
We conclude from this study that it requires additional background data to establish the relationship between LAL test and GC-MS technique for evaluating environmental endotoxin. Furtune work is to identify that which range of endotoxin at which environment can establish stable correlation between two methods. The full application of either method can not be possible until such effort is made.
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