Abstract in English:Treatment of systemic envenoming in snakebite victims has, in the past, depended almost entirely on the individual clinician's experience in assessing the severity of envenoming. The efficacy of treatment is obviously related to the neutralising potency of the antivenom used, the route by which it is administered and the dose. The use of techniques for evaluating the efficacy of antivenoms has proved to be very useful, as an adjunct to recognised clinical observations, for a more objective evaluation of antivenom efficacy and dosage. In patients bitten by many vipers, including the Brazilian pit vipers, the reversal of the venom-induced coagulopathy provides an ideal indicator as to the efficacy of an antivenom. Likewise, the development of enzyme immunoassay has permitted us to estimate levels of circulating specific venom and antivenom levels at any time after the bite in the patient's blood; the efficacy of an antivenom can thus be objectively assessed by measuring the neutralisation and clearance of venom antigen. In Brazil, it appears that clinicians treat patients with excessive amounts of highly efficient antivenoms, which results in an unacceptably high incidence of reactions. In Sri Lanka, the use of imported Indian antivenom is relatively ineffective in neutralising the procoagulant and other effects of the venoms of Sri Lankan snakes, demonstrating the real problem of venom variability within individual species. In West Africa, the improved restoration of blood coagulability, the resolution of haemorrhagic disturbances and the increased rate of clearance of venom following treatment of Echis victims with a monospecific as opposed to a polyspecific antivenom has been demonstrated, and new smaller fragment Fab antivenoms have been developed and are now under clinical assessment. Such clinically based coagulation and immunological studies should result in more efficient and controlled use of expensive antivenoms for treatment of systemic envenoming and the accurate assessment of newly designed products. Such studies also emphasise the importance of individual countries producing their own antivenoms for treatment of systemic envenoming. Likewise, the use of such objective systems now enable us to assess the use of first aid measures such as tourniquets.
Abstract in English:Major clinical signs were depression, vomiting, abdominal pain, weakness, recumbency, paddling convulsions terminating in death from 6 to 96 hours after ingestion. Gross pathological findings included ascites with fibrin strands, enlarged, congested and friable livers with accentuation of lobulation on the capsule. Microscopically, acute hepatic congestion and hemorrhage, centrilobular hepatocyte necrosis, with occasional binucleation together with discoid lysis of skeletal and cardiac muscle fibers were remarkable changes. Binucleation of hepatocytes and degenerative changes in active muscles have not been reported before in relation to cocklebur plant toxicosis. These findings suggest that X. strumarium is a potential cause of sudden death in pigs extensively reared in Zimbabwe.
Abstract in English:The objective of this study was to evaluate the effects of the thrombin-like fraction of Crotalus durissus terrificus venom, Reptilase<img SRC="http:/img/fbpe/jvat/v4n2/image119.gif"> , and bovine thrombin of fibrinogen pools on bovine, equine, ovine, bubaline and human cryoprecipitates. The authors also made a comparative study between animal and human cryoprecipitates to see if any there was any possibility of future use in medicine. Fibrinogen levels in cryoprecipitate were studied using 48 blood samples obtained as follows:12 samples from humans, 9 from bovine, 10 from equine, 10 from ovine and 7 from bubaline. The results obtained showed average levels of 375.50 mg % for humans, 218.33 mg % for bovine, 240.80 mg % for equine, 267.70 mg % for ovine and 664.00 mg % for bubaline. Upon the formation of pools of human and animal fibrinogens, the following results were obtained: 435 mg % for humans, 444 mg % for bovine, 337 mg % for equine, 390 mg % for ovine and 530 mg % for bubaline. Statistical analysis (using the analysis of variance for entirely randomized experiment for the calculation of F statistics) demonstrated that the bubaline fibrinogen level was higher than that of human, and both were higher than those of ovine, equine, and bovine. Clotting times were determined using different dilutions of bovine thrombin, thrombin-like fraction of Crotalus durissus terrificus venom, and Reptilase<img SRC="http:/img/fbpe/jvat/v4n2/image119.gif"> . Comparing these clotting times, results for human and bovine were found to be very similar, whereas using equine, ovine, and bubaline the results above a dilution of 1:3 were markedly different. The results obtained permitted the following conclusions to be drawn show that: 1) bovine thrombin presented better interactivity with fibrinogen extracted both from human and bovine cryoprecipitates; 2) there was similar behavior when bovine thrombin was substituted for Reptilase<img SRC="http:/img/fbpe/jvat/v4n2/image119.gif"> and for the thrombin-like fraction of Crotalus durissus terrificus venom; 3) cryoprecipitate from bovine can, in special circumstances, substitute human cryoprecipitate in medical practice; 4) human and bovine cryoprecipitates can be used with both Reptilase<img SRC="http:/img/fbpe/jvat/v4n2/image119.gif"> and Crotalus durissus terrificus fractions using a dilution up to 1:5; 5) the use of bovine cryoprecipitate can be recommended using either bovine thrombin, Reptilase<img SRC="http:/img/fbpe/jvat/v4n2/image119.gif"> , or thrombin-like fraction of Crotalus durissus terrificus venom.
Abstract in English:Polyacrylamide gel electrophoresis (PAGE) for basic proteins may be a useful tool for the characterization of whole snake venoms and for the taxonomic classification of snakes of the Elapidae and Viperidae families. However, due to the close proximity of molecular weights among toxins bearing different net charges, sodium dodecyl sulfate (SDS) - PAGE was not able to provide an efficient differentiation. This article reports the electrophoretic analysis of several venoms from the genera Micrurus, Bothrops, Bothriopsis, Crotalus and Lachesis and shows a typical and distinctive electrophoretic profile for each species, with intraspecific and geographic variations. Even in cases in which extreme morphological similarities were present, such as between B. jararacussu and B. pirajai ("Bahia jararacuçu"), differentiation could be evidenced by PAGE. This simple and sensitive procedure may be applied to similar cases involving basic toxins.