Masatoshi Kato

Possible cross-linking of factor VIII related antigen to fibrin by factor XIII in delayed coagulation process

The significance of factor VIII related antigen ( VIIIR:AG ) in laboratory medicine has been made clear, but its functions in the coagulation process are still unknown ( 1, 2 ). We previously observed that the concentration of VIIIR:AG in serum was lower than that in plasma of severe hemophilia A patients without inhibitor ( 3, 4 ). In this communication, we report the mechanism of the blood coagulation. consumption of VIIIR:XG in the state of prolonged

Studies on α2-plasmin inhibitor and UK inhibitor in pregnancy and labor

To find out whether the depressed fibrinolytic activity in pregnancy can be ascribed to an increased content of inhibitors in the blood or to a release of inhibitors from the placenta, we studied the variation of the fibrinolytic inhibitors such as α1-AT, α2-MG, AT-III and C1-inactivator during pregnancy. However, we did not find any significant increase in inhibitors. In this paper, the levels of antiplasmin including α2-PI devised by Aoki and UK inhibitors extracted from the placenta by Kawano during pregnancy and delivery were examined.Methods:The material consisted of citrated plasma from pregnant women and extracts from the placenta. α2-PI was assessed with a single radial immunodiffusion method using antiserum made by Aoki. Antiplasmin activity was measured with chromogenic substrate S-2251 and then UK inhibitor was calculated from a standard curve prepared from placental UKI using the chromogenic substrate S-2444. The results were expressed relative to the content of normal standard as %, iu/ml and u/g.Results:1) The levels of α2-PI with a single radial immunodiffusion method correlated well to those of antiplasmin using the chromogenic substrate S-2251.2) Antiplasmin activity including α2-PI remained unchanged throughout pregnancy within 80-130%, and followed a similar patern after delivery. How-ever, it relatively decreased in retroplacental blood as well as uterine venous blood.3) In extracts of the placenta the concentration of antiplasmin was low.4) On the other hand, extract of the placenta contained a high concentration of UKI.5) The concentration of UKI was extremely low in each trimester, but the increased values were noted at term and in labor as well as in retroplacental blood, and gradually decreased after delivery.Discussion: Antiplasmin activity might directly or indirectly act upon the depression of the fibrinolytic activity in pregnancy, but UK inhibitor might be found intensively during placental separation.