Inhibition and Enhancement in the Analysis of Airborne Endotoxin Levels in Various Occupational Environments

Toll-like receptor 2 as a major gene for asthma in children of European farmers

“…For measurement of endotoxin, dust samples were taken from the child's mattress, 13 stored at room temperature, and shipped to a central laboratory (in Munich, Germany). The content of endotoxin in all dust samples was determined by using a kinetic Limulus assay (Bio Whittaker) 18 and expressed in endotoxin units (EU) per milligram. High endotoxin exposure was defined in children with endotoxin concentrations of greater than the median of the study group and compared with those less than the median.…”

Exposure and acute exposure-effects before and after modification of a contaminated humidification system in a synthetic-fibre plant

“…Use of glass-®bre ®lters will have caused underestimation of endotoxin concentration during oil-mist exposure [13]. Spiking of ®lter extracts with reference endotoxins and testing for a dilution effect did not point to interference with oil-mist in our samples [17,18]. However, the small particle size of oilmist (>0.1 lm, <1 lm) loaded with endotoxins might have decreased the recovery rate.…”

“…In comparing the measured levels of endotoxins with those from other studies, dierences in aerosol sampling media, extraction methods and the possibility of inhibition or enhancement in the analysis have to be taken into account [9,13,17]. Use of glass-®bre ®lters will have caused underestimation of endotoxin concentration during oil-mist exposure [13].…”

“…Endotoxin concentrations were determined per work area from pooled personal dust samples (PAS-6 2 l/min, Whatman CF/A glass-®bre ®lters) using the Limulus Amoebocyte Lysate (LAL) assay according to a previously described procedure [17].…”

Chemical and biological evaluation of endotoxin contamination on natural rubber latex products

“…9 The LAL reaction is influenced by the temperature and pH of the sample, and also enhanced or inhibited by various compounds such as protease, protease inhibitors, metal ions, surfactants, chelates, and high concentrations of salts and sugars. [10][11][12][13][14][15][16][17][18][19] In addition, a nonpyrogenic unknown substance present in certain biological products gives a false-positive result on LAL tests specific for LPS. 20,21 Taking these findings into consideration, the presence of a small amount of LPS in natural products may not be identified by LAL assay alone, even if LPS-specific LAL reagent is used, and hence, various experimental tests, in addition to the LAL test, may be required to completely certify LPS pollution in natural products.…”