Clinical significance of bradykinin liberation during cardiopulmonary bypass and its prevention by a kallikrein inhibitor

Activation of the kinin system and effects of Trasylol (Bayer, A.G. Lebukusen, West Germany), a kallikrein inhibitor, were investigated on 52 patients during hemodilutional cardiopulmonary bypass (CPB). Immediately after the start of CPB, neither elevation of bradykinin nor reduction of plasma kininogen (KGN: a precursor of bradykinin) were observed. During CPB, bradykinin level in the blood was markedly elevated, correlating with the significant decrease of kininogen (p less than 0.001). The longer the CPB time, the more marked the reduction of KGN. In the cases requiring over 60 minutes of CPB, the amounts of bradykinin released (4.6-18.0ng/ml) were sufficient to increase capillary permeability as well as peripheral vasodilatation. As shown by the sufnificant increase of hematocrit (p less than 0.005) and the extreme reduction of vascular resistance found at the end of CPB in the prolonged cases. Infusion of Trasylol into the extracorporeal circuit actually prevented the reduction of kininogen and the increase of hematocrit as well as the extreme decrease of vascular resistance in the cases of over 60 minutes CPB. These results clearly point out that Trasylol is beneficial for the prevention of bradykinin liberation and capillary permeability increase and for the maintenance of optimum peripheral vascular tone during CPB. Furthermore, the significance of these findings with regards to complications during and after prolonged CPB was discussed.

[Influence of schizophyllan, streptomycin and rifampicin on histopathological changes in mice infected with tubercle bacilli (author's transl)]

Experimental tuberculosis in mice infected with streptomycin-resistant Mycobacterium tuberculosis SCHACHT strain was treated with streptomycin or rifampicin alone and in combination with schizophyllan. The histopathogical tests of various organs of the treated mice were carried out. 1) In the group of mice treated with streptomycin alone, the moderate focal proliferation of RE cells were seen at the beginning of infection. However, durable activation of RE cells and the prolongation of life-span could not be recognized as compared with control animals. 2) The treatment with streptomycin-schizophyllan combination appeared to be somewhat more effective than schizophyllan alone, the phagocytic capacity being more strongly stimulated. 3) In the group treated with rifampicin alone, the therapeutic effect could be exhibited by the direct antibacterial action of rifampicin, but the activation of RE cells was slight. When rifampicin was discontinued, the growth of tubercle bacilli was rapidly resumed, and the durable therapeutic effect seemed not to be expected. Degeneration of hepatic cells tended to develop. 4) In the group treated with rifampicin-schizophyllan combination, the antibacterial effect of rifampicin appeared to be potentiated by the strong activation of RE cells by schizophyllan, showing the durable therapeutic effects.

Inhibition of kinin formation by a kallikrein inhibitor during extracorporeal circulation in open-heart surgery

Involvement of the kinin system was studied in 58 patients during extracorporeal circulation in open heart surgery. At the onset of extracorporeal circulation, there was no increase of free kinin in blood and no reduction of plasma kininogen, when the latter was expressed as mug bradykinin/mg plasma protein. With the lapse of time, kinin in the blood increased significantly, and decrease of kininogen was also significant. The longer the circulation time, the greater the consumption of kininogen. The site of the kinin formation was presumed to be the heart-lung machine since the level of kinin increased slightly and kininogen decreased gradually in the blood leaving the machine, compared with those levels entering the machine. The difference in kininogen was significantly different from zero at termination of extracorporeal circulation. Administration of a kallikrein-trypsin inhibitor, trasylol (A. G. Bayer), infused into the heart-lung machine, prevented the decrease of kininogen. Reduction of the total peripheral resistance during this circulation was also prevented. The hemoconcentration, presumably the result of vascular permeability increase caused by increased kinin, was prevented by trasylol in cases in which extracorporeal circulation lasted over 60 minutes. Trasylol applied thus appears to be an effective counteragent for circulatory disturbances which occur during extracorporeal circulation.