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Sample records for ancrod

  1. Treatment of severe foot ischaemia by defibrination with ancrod

    DEFF Research Database (Denmark)

    T√łnnesen, K H; Sager, P; Gormsen, J

    1978-01-01

    Forty-two patients, mean age 68 years, with severe leg ischaemia were randomly treated with placebo or by controlled defibrination with ancrod for 3 weeks. Plasma fibrinogen concentration was kept at about 20% of normal in the ancrod treated group. The two groups proved to be well matched regardi...

  2. Treatment of severe foot ischaemia by defibrination with ancrod

    DEFF Research Database (Denmark)

    T√łnnesen, K H; Sager, P; Gormsen, J

    1978-01-01

    factors which could affect the degree of ischaemia. Objective measurements showed a significant rise in ankle and toe systolic blood pressure in the ancrod group lasting for 3 months. There was no rise in distal blood pressure in the control group. In the ancrod treated group the toe and ankle systolic...

  3. Behaviour of homologous 125I fibrinogen after thrombin and ancrod infusion in rabbits

    International Nuclear Information System (INIS)

    Setter, R.

    1977-01-01

    The behaviour of radioactively labelled fibrinogen after infusion of thrombin or ancrod is investigated. Common factors and differences in the behaviour of fibrinogen after infusion of these two enzymes, which act proteolytically on the fibrinogen, are dealt with. Rabbits received an i.v. injection of homologous 125 I-fibrinogen 3 days before ancrod or thrombin infusion. On the day of the experiments, one group of animals received an ancrod infusion (1.5 U/kg body weight for 30 minutes), the other a thrombin infusion (600 U/kg body weight for 60 minutes). Intravenous ancrod and thrombin infusions lowered the fibrinogen level to 30% or 50% of the initial value due to intravascular coagulation. About 50% of the 125 I fibrinogen was transformed after ancrod exposure into a non-coagulating fraction of fibrinogen derivatives which produces no fibrinolytic decomposition products. (orig./AJ) [de

  4. Protease activated receptors (PARS) mediation in gyroxin biological activity

    International Nuclear Information System (INIS)

    Silva, Jose Alberto Alves da

    2009-01-01

    Gyroxin is a serine protease enzyme from the South American rattlesnake (Crotalus durissus terrificus) venom; it is only partially characterized and has multiple activities. Gyroxin induces blood coagulation, blood pressure decrease and a neurotoxic behavior named barrel rotation. The mechanisms involved in this neurotoxic activity are not known. Whereas gyroxin is a member of enzymes with high potential to become a new drug with clinical applications such as thrombin, batroxobin, ancrod, tripsyn and kalicrein, it is important to find out how gyroxin works. The analysis on agarose gel electrophoresis and circular dichroism confirmed the molecules' integrity and purity. The gyroxin intravenous administration in mice proved its neurotoxicity (barrel rotation). In vivo studies employing intravital microscopy proved that gyroxin induces vasodilation with the participation of protease activated receptors (PARs), nitric oxide and Na+K+ATPase. The leukocytes' adherence and rolling counting indicated that gyroxin has no pro inflammatory activity. Gyroxin induced platelet aggregation, which was blocked by inhibitors of PAR1 and PAR4 receptors (SCH 79797 and tcY-NH 2 , respectively). Finally, it was proved that the gyroxin temporarily alter the permeability of the blood brain barrier (BBB). Our study has shown that both the protease-activated receptors and nitric oxide are mediators involved in the biological activities of gyroxin. (author)

  5. Protease activated receptors (PARS) mediation in gyroxin biological activity; Mediacao dos receptores ativados por proteases (PARs) em atividades biologicas da giroxina

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Jose Alberto Alves da

    2009-07-01

    Gyroxin is a serine protease enzyme from the South American rattlesnake (Crotalus durissus terrificus) venom; it is only partially characterized and has multiple activities. Gyroxin induces blood coagulation, blood pressure decrease and a neurotoxic behavior named barrel rotation. The mechanisms involved in this neurotoxic activity are not known. Whereas gyroxin is a member of enzymes with high potential to become a new drug with clinical applications such as thrombin, batroxobin, ancrod, tripsyn and kalicrein, it is important to find out how gyroxin works. The analysis on agarose gel electrophoresis and circular dichroism confirmed the molecules' integrity and purity. The gyroxin intravenous administration in mice proved its neurotoxicity (barrel rotation). In vivo studies employing intravital microscopy proved that gyroxin induces vasodilation with the participation of protease activated receptors (PARs), nitric oxide and Na+K+ATPase. The leukocytes' adherence and rolling counting indicated that gyroxin has no pro inflammatory activity. Gyroxin induced platelet aggregation, which was blocked by inhibitors of PAR1 and PAR4 receptors (SCH 79797 and tcY-NH{sub 2}, respectively). Finally, it was proved that the gyroxin temporarily alter the permeability of the blood brain barrier (BBB). Our study has shown that both the protease-activated receptors and nitric oxide are mediators involved in the biological activities of gyroxin. (author)

  6. Effects of purified human fibrinogen modified with carbon monoxide and iron on coagulation in rabbits injected with Crotalus atrox venom.

    Science.gov (United States)

    Nielsen, Vance G

    2017-11-01

    While snake venom derived enzymes, such as the thrombin-like activity possessing ancrod, have been used to treat thrombotic disease by defibrinogenating patients, the therapeutic potential of fibrinogenolytic snake venom enzymes, such as those derived from Crotalus atrox, have not been fully explored. However, one of the potential risks of administering fibrinogenolytic enzymes to effect defibrinogenation is hemorrhage secondary to hypofibrinogenemia. The present investigation sought to determine if human fibrinogen modified with carbon monoxide (CO) and iron (Fe) could resist degradation by C. atrox venom as has been seen in vitro in a recently developed rabbit model of envenomation. Compared with unmodified human fibrinogen, CO/Fe modified fibrinogen administered prior to envenomation had significantly shorter onset of coagulation and greater strength; however, when administered after envenomation, there was no differences between the two types of fibrinogen. Of interest, when administered after envenomation, both types of fibrinogen delayed the onset of coagulation while increasing plasma clot strength, a mixed effect likely secondary to formation of fibrinogen degradation products. Further preclinical investigations are needed to further define the benefits and risks of the use of fibrinogenolytic enzymes as defibrinogenating agents, as well as the risks of the "biochemical brakes" used to modulate the activity or substrate of the fibrinogenolytic enzyme.