DESORPTION OF PLASMA FIBRINOGEN FROM GLASS: ROLE OF HIGH MOLECULAR WEIGHT KININOGEN (HMWK) AND FACTOR XI.

Fibrinogen displays high affinity for surfaces and has been implicated in thrombosis initiated by foreign surfaces. Fibrinogen is detected on a surface immediately after exposure to plasma but becomes unmeasurable after 10 min. HMWK in plasma adsorbs to glass and remains detectable at 10 min when fibrinogen can no longer be measured. Fibrinogen adsorbed from plasma is replaced on the surface (by HMWK? ) and the replacement is dependent on the concentration of other plasma components. Identification of the replacing species is investigated in the present work. Adsorption of fibrinogen from plasmas diluted to various extents was measured by adding a tracer of **1**2**5I-labelled fibrinogen to the plasma. Glass tubing was then exposed to the plasma under static conditions for 5 minutes, and the radio-activity bound to the surface was measured.