Studies on tissue thromboplastin

Abstract

Tissue thromboplastin (TP) in gastric cancer tissue (Ca) from 9 patients were studied in comparison with that in normal mucous membrane (Ul) and muscular plus serous membrane (M) from the resected stomach of 8 patients with gastric ulcer. Azocaseinolytic activity and fibrinolytic activity (measured by standard fibrin plate method) were also studied.Average TP activities measured by Nemerson's two stage method of the homogenates of Ca, Ul and M were 301±289 (SD), 123±76, and 34±19 units per mg protein, respectively. The activities of the former two were as strong as it of purified human brain TP. These homogenates also contained azocaseinolytic and fibrinolytic activities. These activities exist in granular fractions in differential centrifugation studies. Desoxycholate (DOC) extracts obtained by the method reported previously from Ca and Ul contained substance which showed partial identical antigenicity to purified human placenta TP (PTP) apoprotein by Ouchterlony analysis. DOC extracts regained TP activity when relipidated with phospholipid mixture (PL) from Ca. Similar result was obtained when PL from human brain was substituted for PL from Ca. In both cases, optimum ratio was obsereved in PL/protein and it was 1.3 for Ca and 0.16 to 0.33 for Ul. Relipidated TP activities of DOC extracts of three cases of Ca and a case of Ul seems to be dependent on Factors VII, X and V but not on Factors IX and VIII. Relipidated DOC extracts of a case of Ca and a case of Ul did not show azocaseinolytic and fibrinolytic activities. Anti-PTP γ-globulin fraction neutralized about 90% of the TP activities of the homogenates of Ca and Ul time dependently.These results suggest that Ca and Ul tissues contain TP, which is lipoprotein, and has same properties to TPs from other tissues, and independent from fibrinolytic and protease activities.