The significant enhancement of fibrinolysis by calcium ion in a cell free system: the shortening of euglobulin clot lysis time by calcium ion.
We investigated the roles of calcium ion (Ca2+) on euglobulin clot lysis time (ECLT) and found that the physiological concentration of Ca2+ significantly (4-5 times) shortened ECLT. The shortening was observed at the concentration of Ca2+ higher than 1.5-2.0 mM. Other divalent cations such as Mg2+, Zn2+ or Mn2+ didn't change ECLT. Anti-tPA antibody or plasminogen activator inhibitor-1 prolonged ECLT in the absence of Ca2+, whereas they had no effect on ECLT shortened by Ca2+. C1 inactivator also had no effect. When barium absorbed plasma was employed, the shortening of ECLT by Ca2+ wasn't observed, whereas it was recovered by the readdition of barium absorbed fraction. When factor X deficient plasma was employed, the shortening of ECLT by Ca2+ was also not observed. Thus, Ca2+ enhances fibrinolysis in a cell free system by a novel pathway in which the presence of factor X is prerequisite.
Department of Internal Medicine, Hamamatsu University School of Medicine, Shizuoka-ken, Japan.
Y
Y
Kojima
T
T
Urano
K
K
Kojima
K
K
Serizawa
Y
Y
Takada
A
A
Takada
D000042:Absorption; D001464:Barium / Q000493:pharmacokinetics; D001780:Blood Coagulation Tests; D002118:Calcium / Q000494:pharmacology*; D002474:Cell-Free System; D005342:Fibrinolysis / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D013997:Time Factors
D001464:Barium; D002118:Calcium