Automated limulus amebocyte lysate (LAL) test for endotoxin analysis using a new Toxinometer ET-201.
1985; National Institutes of Health; Volume: 39; Issue: 5 Linguagem: Inglês
Autores
Haruki Oishi, Aya Takaoka, Yasumichi Hatayama, Tetsuya Matsuo, Yoshitsugu Sakata,
Tópico(s)Immune Response and Inflammation
ResumoA precise, efficient, automated method to perform Limulus Amebocyte Lysate (LAL) tests has been developed by using a new Toxinometer ET-201, which measures the turbidity change in gel-clotting in the LAL/endotoxin reaction. This instrument monitors the ratio R(t) of the sequential to the initial transmittance of up to 64 samples simultaneously and independently at 12 sec increments, and quantifies endotoxin by determining the gelation time of the sample defined as the time required to obtain a 5% decrease of R(t). The well correlated standard curve was obtained for endotoxin concentration from 0.0005 EU/ml to 500 EU/ml. CVs of the calculated endotoxin concentration were 5.64 to 14.1%. The detection of endotoxin obtained by this new method agreed well with positive or negative score obtained by the conventional gel-clot method. This method also made it possible to determine precise amounts of endotoxin among these samples previously only scored as negative or positive. Furthermore, using this instrument, inhibition or enhancement of various drugs on the LAL/endotoxin reaction could be quantitatively determined by observing alteration in the gelation time. We also found out that the titrating curves inhibited or enhanced by drugs shifted in parallel with the titrating curve obtained without these drugs. We can estimate the contamination of endotoxin in drugs by graphical extrapolation to the presumed titrating curve with endotoxin-free drugs. The Toxinometer ET-201 method will be very useful for the objective, quantitative determination of endotoxin in routine clinical and pharmaceutical analysis.
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