A phospholipase A2 has been isolated from Bothrops jararacussu venom from snakes that inhabit the northeast region of Argentina. The present study describes in vivo and in vitro biological activities of phospholipase A2 from B. jararacussu as well as isolation details of its. Venom was obtained by milking of adult snakes which were housing in wood reptile cages of varying dimensions in heated (20-30ºC) rooms. Snakes received a weekly diet of mice and water was available ad libitum for drinking and soaking. The enzyme was purified by gel filtration on a Sephadex G-75 column followed by ion exchange chromatography on a SP-Sephadex C25 column. The major peak belonging to proteins was retained in the cation exchanger and then eluted using a concentration gradient of KCl that exhibited phospholipase activity. This basic PLA2 consists of a single polypeptide chain with a molecular mass of 15.6 kDa. It had a high indirect hemolytic activity and produced a significant paw edema reaction in mice. The enzyme showed a low lethality (LD50 148.6 mg) when was administered i.p. but exhibited elevated myotoxic effects in vivo by increasing plasma CK activity of injected mice, corroborated results by the histological observations of samples of gastrocnemius muscle. Myonecrosis is the result of intense destruction of muscular fibers that involves local infiltration of inflammatory cells and leads to the highest peak of CK level just after 1 hour mice injection. Moreover, the isolated enzyme showed anticoagulant activity, evaluated on sheep platelet-poor plasma which recalcification time was prolonged after incubation with the isolated phospholipase A2. These findings showed that this phospholipase, isolated by only two simple chromatographic steps, possesses high edematogenic and myotoxic activities. However, despite the low lethal activity, this enzyme would contribute markedly to the pathophysiology of the bothropic envenomation.

The envenomation by snakes of the genus Bothrops of Argentina causes local and systemic signs. Among the systemic damages, bothropic venoms induce a wide variety of effects on blood coagulation, haemorrhage, shock and renal failure. In this paper the effects of Bothrops jararacussu venom from Argentina on the hemostatic system were determined. In order to estimate blood-clotting, fibrinolytic and defibrinating activities of the venom, in vitro and in vivo tests were employed. The ability to degrade fibrinogen and the lethal dosis (DL50) also were determined. The B. jararacussu venom appears to be fibrinogenolytic and the values obtained for assayed activities were minimum blood-clotting concentration 18,5 μg/ml, minimum fibrinolytic dose 9,5 mg/ml, minimum defibrinating dose 1,56 μg, LD50 43,52 μg/mouse. These results differ from those obtained for other species of genus Bothrops, or from the same species that inhabits in different South American regions. It is concluded that Bothrops jararacussu venom from Argentina largely affects blood coagulation system, and that the procoagulant and anticoagulant activities exhibited by this secretion may contribute to the lethality of the venom, since they could promote hemorrhages which could lead to renal failure and death of the victim in severe envenomation.

La intoxicación por mordeduras de serpientes del género Bothrops (yarará) de Argentina se caracteriza por causar efectos locales y sistémicos. Entre los sistémicos pueden generar alteraciones en la coagulación de la sangre, hemorragias, shock, insuficiencia renal. En este trabajo se estudiaron los efectos que causa el veneno de Bothrops jararacussu de Misiones, Argentina, sobre la coagulación de la sangre. Se utilizaron métodos in vitro e in vivo para evaluar la actividad coagulante, fibrinolítica y defibrinante, como así también la capacidad de degradar el fibrinógeno y la letalidad del veneno. El veneno mostró ser α-fibrinogenolítico y los resultados para las actividades ensayadas fueron: concentración coagulante mínima (CCM) 18,5 μg/ml, concentración fibrinolítica mínima (CFM) 9,5 mg/ml, dosis defibrinante mínima (DDM) 1,56 μg, DL50 43,52 μg/ratón, los que difieren de los obtenidos para otras especies de Bothrops e incluso dentro de la misma especie, pero distribuídas en otras regiones sudamericanas. Se concluye que el veneno de B. jararacussu de Argentina afecta marcadamente el sistema hemostático, y que las actividades coagulantes y anticoagulantes exhibidas por esta secreción probablemente influyan en la letalidad del veneno, dado que contribuirían a la aparición de hemorragias que, de ser severas, conducen a fallo renal y muerte de la víctima.

Descreve-se a sintomatología e o tratamento de dois cães picados por cascavel da America do Sul (Crotalus durissus terrificus) na Argentina. Sinais neurológicos foram evidentes poucos minutos após o acidente, incluindo anestesia local, ataxia do membro afetado e fascia neurotóxica. As enzimas aminotransferase da alanina, aminotransferase do aspartato, quinase da creatinina, desidrogenase de lactato e o cálcio foram determinados para analisar dano muscular. Falha renal não foi observada, mas algunas alterações foram detectadas na urina, incluindo densidade baixa, sedimento com grumos granulares e células pequenas redondas. Biópsias de músculo foram obtidas de ambas as pernas para histopatología, revelando edema e fibras necróticas isoladas. Ambos os cães receberam tratamento quatro horas após o acidente, pela via intravenosa. A antitoxina foi administrada diluída em 250ml de solução Ringer lactato na dose capaz de neutralizar 8mg de toxina. Dexametasona foi aplicada antes de administrar a antitoxina. A evolução clínica foi boa e ambos os pacientes estavam com boa saúde no segundo dia após o acidente.

The symptomatology and treatment of two dogs bitten by Crotalus durissus terrificus are described. Neurological signs were present few minutes after the accident with local anesthesia and ataxia of the affected limb and neurotoxic fascia. Alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatinine kinase (CK), lactate dehydrogenase (LDH) and calcium were evaluated in an attempt to investigate muscle damage. Renal failure was not observed but some alterations were detected in urine. Urine density was low and the urinary sediment contained granular clumps and small round cells. Muscle samples were obtained from both legs for histopathological study, showing edema and isolated necrotic fibers. Both dogs received treatment within four hours after the accident by intravenous route. The antivenom was administered diluted in 250ml of Ringer solution in a dose enough to inactivate more than 8mg of venom. Dexamethasone was applied previously to the antivenom. Clinical evolution was good and both patients were in good health condition on the second day after the accident.