Is a Cofactor for Activated Protein C Neutralization of an Inhibitor of Plasminogen Activation Released From Platelets

نویسندگان

  • Armando D’Angelo
  • Marion S. Lockhart
  • Silvana Vigano
چکیده

Platelets stimulated with thrombin release an inhibitor of plasminogen activator (PAl). which has been shown previously to be neutralized by activated protein C (APC). The requirements for optimal neutralization of PAl activity were investigated. The releasate of gel-filtered human platelets stimulated with thrombin served as a source of PAl. When 6 x i08 platelets/mi were incubated with thrombin (1 lU/mi). the releasate contained 18 to 26 ng/mi PAl as determined by incubation of the releasate with urokinase and measurement of residual urokinase activity on plasminogen (52251 ). Preincubation of PAl with up to 4 pg/mi APC for two hours yielded less than 20% neutralization of PAl activity. In the presence of protein S. phospholipid, and Ca2 . neutralization of PAl activity was

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تاریخ انتشار 2005