QUANTITATIVE-ANALYSIS OF PLATELET-ACTIVATING-FACTOR IN HUMAN PLASMA -APPLICATION TO PATIENTS WITH LIVER-CIRRHOSIS AND DISSEMINATED INTRAVASCULAR COAGULATION

A simple and reliable analytical procedure was developed for determina tion of platelet-activating factor (PAF) in human plasma using radioim munoassay (RIA). The assay system consisted of lipid extraction with 2 -propanol, lipid separation by Amprep octadecyl minicolumn chromatogra phy and thin-layer chromatography and RIA (charcoal method), and was s uitable for quantitation of 30-1000 pg of PAF. The sensitivity of RIA for PAF was notably higher than that for sn-2-short-chain PAF-like pho sphatidylcholines. This assay system was then applied for measurement of PAF in human plasma. The normal level of plasma PAF was 54 +/- 40 p g/ml (n = 35), whereas plasma PAF levels in patients with liver cirrho sis (LC) and disseminated intravascular coagulation (DIC) were signifi cantly elevated to 238 +/- 314 pg/ml (n = 14) and 591 +/- 328 pg/ml (n = 14), respectively. The values obtained using this assay system were comparable to those obtained by gas chromatography/mass spectrometry analysis and bioassay. These results indicate that our new assay syste m is useful for determining changes in the level of plasma PAF associa ted with diseases such as LC and DIC.