title: Parallel line assays of endotoxins with the LAL chromogenic substrate method.
abstract: All endotoxins from the gram negative microorganisms studied sofar contain lipid A, which is considered to be responsible for the biological activity. Endotoxins may therefore react in a similar way in quantitative assays. The varying non-lipid A part of different endotoxins may potentiate or reduce the activity of the identical lipid A part without changing the slope of the log-dose vs. response curve of these endotoxins. To test whether 13 endotoxins from different microorganisms react similarly with amoebocyte lysate (LAL) log-dose response curves were made using a chromogenic substrate method. A balanced incomplete block design with 13 blocks and four replications of each endotoxin was applied. A group of eight endotoxins with a common slope was defined with the Student-Newman-Keuls procedure. Two independent potency estimates of these endotoxins were in good agreement.
mesh_terms: D000704:Analysis of Variance; D002863:Chromogenic Compounds; D004305:Dose-Response Relationship, Drug; D004731:Endotoxins / Q000032:analysis*; D008033:Limulus Test; D012044:Regression Analysis
chemical_list: D002863:Chromogenic Compounds; D004731:Endotoxins