著者

山下 勉 香西 かおり 井上 典子 三村 幸一 松岡 瑛

出版者

The Japanese Society on Thrombosis and Hemostasis

雑誌

日本血栓止血学会誌 (ISSN:09157441)

巻号頁・発行日

vol.3, no.1, pp.49-56, 1992

被引用文献数

2

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We have investigated the use of synthetic thrombin inhibitors in assays of thrombin-antithrombin III complexes (TAT). In a purified system, when antithrombin III (AT-III) was incubated with thrombin, a complex of 90KD was formed gradually during the first 60 minutes and this complex was converted to lower molecular weight species (78-86×10³) within 48 hours. Additionally, the interaction of thrombin and AT-III was studied in the presence of heparin. A 93KD complex was formed immediately and then lower molecular weight complexes (78-86×10³) were formed during 60 minutes of incubation. In these circumstances, therefore, heparin seemed to accelerate the breakdown of TAT complexes. Plasma values of TAT were measured by ELISA in the presence of heparin and were reduced by approximately 55per cent during 48 hours of incubation. These findings suggested that the biochemical nature of TAT was modified during incubation, and that the assays for TAT in plasma might not detect lower molecular weight forms of the complex. However, a synthetic thrombin inhibitor, argatroban (0.1mM/<i>l</i>) prevented these changes. The levels of TAT in plasma were increased by adding tissue factor or contact factor activator to the assay mixture. Argatroban (0.01mM/<i>l</i>) or another synthetic protease inhibitor, FOY (4.3mM/<i>l</i>), inhibited this generation of TAT. These observations suggested that argatroban minimized the changes of TAT molecular weight and prevented generation of TAT <i>in vitro</i>. The data indicated that the addition of argatroban (final concentration 0.1mM/<i>l</i>) to plasma would permit more accurate measurements of circulating levels of TAT.