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A plasmin generation method for the determination of tissue plasminogen activator (t‐PA) activity in blood
Author(s) -
Koh SCL,
Yuen R,
Viegas OAC,
Chua SE,
Ng BL,
Sen DK,
Ratnam SS
Publication year - 1989
Publication title -
immunology and cell biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.999
H-Index - 104
eISSN - 1440-1711
pISSN - 0818-9641
DOI - 10.1038/icb.1989.30
Subject(s) - plasmin , tissue plasminogen activator , plasminogen activator , chemistry , microbiology and biotechnology , medicine , biochemistry , biology , enzyme
Summary A plasmin generation method to determine tissue plasminogen activator (t‐PA) activity in plasma is described, A protein solution of homogenized fibrin was used as a stimulator in the presence of plasminogen and the plasmin generated was measured by the release of para‐Nitroanilide (p‐NA) from the chromogenic substrate S‐2251. Plasmin generation by 5 iu/mL t‐PA in the presence of 1 CU/mL of plasminogen and 850μg/mL of fibrin solution reaches a peak at about 5 h incubation whilst in plasma, plasmin generation peaks after about 16 h incubation. The highest t‐PA activity in plasma was determined using an assay involving 18 h incubation. In the 21 subjects studied by this method the t‐PA activity at rest ranged from 0·34 to 0·92 iu/mL, with a mean of 0·57 ± 0·15 iu/mL of plasma whilst in the post‐occlusion state the activity ranged from 1·12 to 18·0 iu/mL, with a mean of 5·25 ± 4·49 iu/mL of plasma. We also found that subjects who developed petechiae during occlusion had significantly higher t‐PA activity both at pre‐ and post‐occlusion when compared with those who did not develop petechiae. The t‐PA activity of acid‐treated plasma stored at — 70°C showed no significant changes in activity after 12 weeks of storage when compared with the t‐PA activity of the same plasma tested prior to storage.