Undiluted plasma samples (1-3 [micro]L) were electrophoresed in 25 cm x 12 cm x 0.5 mm slab gels composed of 1% low
electroendosmosis agarose (Bio-Rad Laboratories) without albumin for 1-3 h at 150 V in a barbital/EDTA buffer system (50 mmol/L barbital, 20 mmol/L barbituric acid, 1 mmol/L sodium EDTA, pH 8.5) using water-cooled (4[degrees]C) flat-bed electrophoresis chamber (Multiphor II and Multitemp III; Pharmacia Biotech).