L. Mussoni

Plasminogen assay in rabbit, rat and mouse plasma using the chromogenic substrate S-2251

Abstract An amidolytic assay has been developed for measuring plasminogen in rabbit, rat and mouse plasma using the synthetic substrate S-2251. The assay includes an acidification step to make plasminogen more readily activatable; the conditions required for optimal activation of plasminogen by urokinase were found to vary in the 3 animal species studied. Compared with human plasma, rat, mouse and rabbit plasma (in decreasing order) all had higher plasminogen activity. A close correlation was found between amidolytic and caseinolytic assay of plasminogen in all species studied. The method described may be of significant help in the study of the fibrinolytic system of laboratory animals.

Growth and metastasis of the Lewis lung carcinoma in mice defibrinated with batroxobin

Abstract Lewis lung carcinoma ( 3 LL) cells were implanted intramuscularly into C 57 B 16 J mice, rendered hypofibrinogenemic by daily intraperitoneal treatment with batroxobin ( 17.5 NIH u/kg body wt, twice per day). When this treatment was continued till spontaneous death of the animals, an increase in both metastasis number and weight was observed, but the primary tumor growth was unchanged. In contrast, both metastasis number and weight tended to decrease when defibrination was started from day 11 after tumor implantation, independently from surgical removal of the primary tumor. These data suggest that fibrinogen and/or its derivatives could play a different role in the various stages of the growth and dissemination of the same experimental tumor.

Delayed hypercoagulability after a single dose of adriamycin to normal rats

Abstract Single doses of Adriamycin to normal rats, at levels active as an anticancer agent in this animal species, did not induce any acute changes in haemostatic parameters such as blood platelets, fibrinogen level or spontaneous fibrinolytic activity, as long as plasma drug levels were measurable. Starting from 2 weeks after a single dose, however, a hypercoagulable state developed, characterized by increased fibrinogen and factor VIII levels, short activated partial thromboplastin time, low antithrombin levels and depressed fibrinolytic activity. These changes were dose-related and lasted at least 5 weeks after treatment. An increased tendency to occlusive arterial thrombosis was also observed in treated rats. The pathogenesis of this disorder could be related to tissue damage induced by the drug, possibly nephrotoxicity.

Blood coagulation changes in JW sarcoma, a new metastasizing tumour in mice

Abstract A new murine tumour, which arose spontaneously in the lung, was characterized as a possible model of blood clotting changes during tumour and metastasis growth. The JW sarcoma (JWS), when transplanted s.c. in BALB/c mice, grows locally and spontaneously metastasizes to the lungs. The transplanted animals survive for 6 weeks . Thrombocytopenia and increased leukocyte count were observed during the metastasis growth. Concomitantly, increased fibrinogen level and reduced fibrinolytic activity were observed. At 4 weeks after tumour implantation, survival of labelled fibrinogen was prolonged. This experimental model may offer useful information on the haematological and blood clotting changes in cancer patients.

Effect of ditazole, an inhibitor of platelet aggregation, on a metastasizing tumour in mice

Effect of ditazole, an inhibitor of platelet aggregation, on a metastasizing tumour in mice