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Interlaboratory evaluation of endotoxin analyses in agricultural dusts - comparison of LAL assay and mass spectrometry

Reynolds, SJ; Milton, DK; Heederik, D; Thorne, PS; Donham, KJ; Croteau, EA; Kelly, KM; Douwes, J; Lewis, D and Whitmer, M, et al. (2005) In Journal of Environmental Monitoring 7(12). p.1371-1377
Abstract
Endotoxin exposure is associated with wheeze and asthma morbidity, while early life exposure may reduce risk of allergy and asthma. Unfortunately, it is difficult to compare endotoxin results from different laboratories and environments. We undertook this study to determine if lipopolysaccharide ( LPS) extraction efficiency could account for differences among laboratories. We generated and collected aerosols from chicken and swine barns, and corn processing. We randomly allocated side-by-side filter samples to five laboratories for Limulus assay of endotoxin. Lyophilized aliquots of filter extracts were analyzed for 3-hydroxy fatty acids ( 3-OHFAs) as a marker of LPS using gas chromatography-mass spectrometry. There were significant... (More)
Endotoxin exposure is associated with wheeze and asthma morbidity, while early life exposure may reduce risk of allergy and asthma. Unfortunately, it is difficult to compare endotoxin results from different laboratories and environments. We undertook this study to determine if lipopolysaccharide ( LPS) extraction efficiency could account for differences among laboratories. We generated and collected aerosols from chicken and swine barns, and corn processing. We randomly allocated side-by-side filter samples to five laboratories for Limulus assay of endotoxin. Lyophilized aliquots of filter extracts were analyzed for 3-hydroxy fatty acids ( 3-OHFAs) as a marker of LPS using gas chromatography-mass spectrometry. There were significant differences in endotoxin assay and GC-MS ( LPS) results between laboratories for all dust types ( p < 0.01). Patterns of differences between labs varied by dust type. Relationships between assay and GC/MS results also depended on dust type. The percentages of individual 3-OHFA chain lengths varied across labs ( p < 0.0001) suggesting that each lab recovered a different fraction of the LPS available. The presence of large amounts of particle associated LPS and absence of a freezing thawing cycle were associated with lower correlations between LPS and bioactivity, consistent with an absence of Limulus response to cell-bound endotoxin. These data suggest that extraction methods affect endotoxin measurements. The LAL methods may be most suitable when comparing exposures within similar environments; GC-MS offers additional information helpful in optimizing sample treatment and extraction. GC-MS may be of use when comparing across heterogeneous environments and should be considered for inclusion in future studies of human health outcomes. (Less)
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Journal of Environmental Monitoring
volume
7
issue
12
pages
1371 - 1377
publisher
Royal Society of Chemistry
external identifiers
  • pmid:16307099
  • wos:000233459000037
  • scopus:29244437512
ISSN
1464-0325
DOI
10.1039/b509256f
language
English
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yes
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5e7ecebe-973b-459d-9cf9-1e66f20b1a4c (old id 212124)
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2007-08-15 14:42:31
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@article{5e7ecebe-973b-459d-9cf9-1e66f20b1a4c,
  abstract     = {Endotoxin exposure is associated with wheeze and asthma morbidity, while early life exposure may reduce risk of allergy and asthma. Unfortunately, it is difficult to compare endotoxin results from different laboratories and environments. We undertook this study to determine if lipopolysaccharide ( LPS) extraction efficiency could account for differences among laboratories. We generated and collected aerosols from chicken and swine barns, and corn processing. We randomly allocated side-by-side filter samples to five laboratories for Limulus assay of endotoxin. Lyophilized aliquots of filter extracts were analyzed for 3-hydroxy fatty acids ( 3-OHFAs) as a marker of LPS using gas chromatography-mass spectrometry. There were significant differences in endotoxin assay and GC-MS ( LPS) results between laboratories for all dust types ( p &lt; 0.01). Patterns of differences between labs varied by dust type. Relationships between assay and GC/MS results also depended on dust type. The percentages of individual 3-OHFA chain lengths varied across labs ( p &lt; 0.0001) suggesting that each lab recovered a different fraction of the LPS available. The presence of large amounts of particle associated LPS and absence of a freezing thawing cycle were associated with lower correlations between LPS and bioactivity, consistent with an absence of Limulus response to cell-bound endotoxin. These data suggest that extraction methods affect endotoxin measurements. The LAL methods may be most suitable when comparing exposures within similar environments; GC-MS offers additional information helpful in optimizing sample treatment and extraction. GC-MS may be of use when comparing across heterogeneous environments and should be considered for inclusion in future studies of human health outcomes.},
  author       = {Reynolds, SJ and Milton, DK and Heederik, D and Thorne, PS and Donham, KJ and Croteau, EA and Kelly, KM and Douwes, J and Lewis, D and Whitmer, M and Connaughton, I and Koch, S and Malmberg, P and Larsson, BM and Deddens, J and Saraf, A and Larsson, Lennart},
  issn         = {1464-0325},
  language     = {eng},
  number       = {12},
  pages        = {1371--1377},
  publisher    = {Royal Society of Chemistry},
  series       = {Journal of Environmental Monitoring},
  title        = {Interlaboratory evaluation of endotoxin analyses in agricultural dusts - comparison of LAL assay and mass spectrometry},
  url          = {http://dx.doi.org/10.1039/b509256f},
  volume       = {7},
  year         = {2005},
}