Abstract
The heparinized plasma collected from 11 non-treated, 10 agar-injected rabbits and 10 heparinized acidified plasma samples were eluated by column chromatography (G-25, G-50, G-200, DEAE-cellulose and DEAE-Sephadex A-50) or treated by starch-block electrophoresis. Using column chromatography fo G-25, G-50 or G-200, the platelet-clumping activity was found in the protein fractions. Using chromatography of DEAE-cellulose, the platelet-clumping activity was eluated in 1.5 M NaCl containing phosphate buffer, pH 6.0. Using chromatography of DEAE-Sephadex A-50, it was eluated in 0.17 M NaCl containing phosphate buffer following the albumin fraction. Using starchblock electrophoresis, the platelet-clumping activity was found in the albumin band and/or in fractions containing a component of faster mobility than that of albumin (pre-albumin fraction). Platelet-clumping activity was also detected in electrophoretic extracts of plasma from non-treated rabbits which, prior to electrophoresis, had not shown any platelet-clumping activity. Starchblock electrophoresis may serve to activate the platelet-cluming substance or remove some inhibitor in the plasma. The eluates collected through the above mentioned procedures clumped platelets not only in citrated plateletrich plasma but also in platelet-saline suspension without calcium ions. It was not dialyzable against running water for 72 hours; it was heat-stable at 100°C for 15 min.; it failed to demonstrate a peak around 260 mμ in the ultraviolet absorption test.
