title: Enhancing effect of platelets on staphylokinase-mediated clot lysis and plasminogen activation.
abstract: The effects of platelets on clot lysis and plasminogen activation by staphylokinase (SAK) were investigated. At concentrations ranging from 2 x 10(-7) to 1 x 10(-5)g/ml of SAK, the lysis time of platelet-rich plasma clots (PRP-clots) was shorter than that of platelet-poor plasma clots (PPP-clots). This reduction of clot lysis time was observed in a dose-dependent manner on platelet count in PRP. The activation rate of plasminogen by SAK measured by the amidolytic method using S-2251 was enhanced by the addition of washed platelets. These enhancing effects of platelets on clot lysis and plasminogen activation were not altered by pretreatment of platelets with indomethacin and theophylline, but were diminished by platelet disruption. Thus, we concluded that platelets enhance fibrinolytic activity of SAK, and this effect is not due to the release reaction or intracellular contents of platelets, but to the existence of platelet surface in the intact shape as a catalytic site for fibrinolysis.
authors.affiliation: Second Department of Internal Medicine, Hyogo College of Medicine, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Suehiro
authors.forename: H
authors.initials: H
authors.lastname: Tsujioka
authors.forename: H
authors.initials: H
authors.lastname: Yoshimoto
authors.forename: M
authors.initials: M
authors.lastname: Ueda
authors.forename: S
authors.initials: S
authors.lastname: Higasa
authors.forename: E
authors.initials: E
authors.lastname: Kakishita
mesh_terms: D001792:Blood Platelets / Q000502:physiology*; D005342:Fibrinolysis / Q000187:drug effects*; D005343:Fibrinolytic Agents / Q000494:pharmacology*; D006801:Humans; D007213:Indomethacin / Q000494:pharmacology; D008666:Metalloendopeptidases / Q000494:pharmacology*; D010958:Plasminogen / Q000187:drug effects / Q000378:metabolism*; D010976:Platelet Count; D013806:Theophylline / Q000494:pharmacology
chemical_list: D005343:Fibrinolytic Agents; D010958:Plasminogen; D013806:Theophylline; D008666:Metalloendopeptidases; C022653:auR protein, Staphylococcus aureus; D007213:Indomethacin