Abstract in English:Since 1949, a great deal of research has been carried out on the radioprotective action of chemical substances. These substances have shown to reduce mortality when administered to animals prior to exposure to a lethal dose of radiation. This fact is of considerable importance since it permits reduction of radiation-induced damage and provides prophylactic treatment for the damaging effects produced by radiotherapy. The following radioprotection mechanisms were proposed: free radical scavenger, repair by hydrogen donation to target molecules, formation of mixed disulfides, delay of cellular division and induction of hypoxia in the tissues. Radioprotective agents have been divided into four major groups: the thiol compounds, other sulfur compounds, pharmacological agents (anesthetic drugs, analgesics, tranquilizers, etc.) and other radioprotective agents (WR-1065, WR-2721, vitamins C and E, glutathione, etc.). Several studies revealed the radioprotective action of Apis mellifera honeybee venom as well as that of its components mellitin and histamine. Radioprotective activity of bee venom involves mainly the stimulation of the hematopoietic system. In addition, release of histamine and reduction in oxygen tension also contribute to the radioprotective action of bee venom.
Abstract in English:Sequelae due to testicular biopsy such as hemorrhage, adhesion and fibrosis may be limiting factors to the use of this surgical procedure. Fibrin glue (FG) derived from snake venom was used to minimize these sequelae, as well as to evaluate its healing property in tunica vaginalis and scrotal skin of rams. Applicability of fibrin glue derived from snake venom was tested in different tissues of other animals such as in sciatic nerve and colon of rats and skin of rabbits. In the present study, 30 healthy adult rams were used. They were divided into 3 groups of 10 animals each as follows: G1: fibrin glue group (application of fibrin glue on puncture sites and skin incisions after bilateral testicular biopsy with a Tru-Cut needle); G2: swab/nylon group (hemostasis by compression with a swab on puncture sites and skin suturing with nylon after biopsy) and G3: control group (the animals were not subjected either to biopsy or to surgery). On the 20<IMG SRC="Image485.gif" WIDTH=10 HEIGHT=17> day after biopsy, the presence of adhesion strands between the sites of skin incision and testicle was evaluated by palpation. Adhesion strands were found in three testicles (15%) in G1 and in two testicles (10%) in G2. One hundred days after biopsy, orchiectomy was carried out and the material collected was assessed for subcutaneous (SC) and/or tunica vaginalis adhesions. G3 did not present any abnormality. Groups G1 and G2 presented four testicles each (20%) with adhesion between the tunics at biopsy site. On the other hand, subcutaneous adhesions were found once (5%) in G1 and three times (15%) in G2. Fibrin glue showed to be of easy application, required short postoperative monitoring, presented fast and good-quality healing property and tended to reduce formation of subcutaneous adhesion.
Abstract in English:The venom of many dangerous Australian snakes has a myotoxic component and some are strongly myolytic. The myotoxicity of venom of seven Australian elapid snakes was studied to determine their relative in vitro potency in causing cell death of C2C12 cells, a myoblast cell line, and murine myotubes in mixed cell culture. The venom of Pseudechis australis proved to be the most myotoxic, Austrelaps superbus and Pseudechis porphyriacus venoms also exhibited high myotoxicity relative to the other venoms tested. The specificity of Pseudechis porphyriacus venom was tested using the human glioma cell line TC3 and was shown to exhibit a general cytotoxicity. Myotoxicity, however, was the predominant action of the venom. It has long been known that certain animals such as the mongoose (Herpestes edwardsii) are able to survive envenomation. Some species of snakes also possess this property and the neutralising factor(s) responsible for this in P. porphyriacus has been shown to be present in the serum. The protective effect of homologous plasma from P. porphyriacus venom was also studied with reference to myotoxicity and cytotoxicity. The results of this study clearly demonstrated protection by homologous plasma using a myoblast cell line, C2C12, a primary mixed cell culture and TC3 cells. While protection was clear, particularly using high concentrations of venom, it was not absolute, and homologous plasma did not afford continued protection from the effects of the venom. In the mixed cell culture experiments venom/plasma mixtures pre-incubated for 30 min were more protective than venom/plasma mixtures which were not pre-incubated, in contrast to the results of cell culture studies, which showed little difference.
Abstract in English:A characteristic of the bovine paraplegic syndrome (BPS) is ventral or sternal decubitus in animals that make unsuccessful efforts to stand when stimulated. Death occurs after a few days. In a previous work we showed the existence of a sodium channel blocking toxin (SCBT) produced by ruminal bacteria in cattle with or liable to develop BPS. The presence of SCBT in bovine plasma sampled monthly during the rainy and dry seasons in animals without BPS has now been observed. A positive correlation between rain precipitation and plasma toxin levels (Spearman's rank correlation coefficient=0.457, n=135, p<10<img SRC="http:/img/fbpe/jvat/v4n1/image522.gif"> ) was found. Precipitation was 194 (121-289) mm water/month (n= 162 months in 27 years, median and its 95% confidence interval) during the rainy season and 7 (0-35) mm water/month (n=109 months in 28 years) during the dry season [p < 10<img SRC="http:/img/fbpe/jvat/v4n1/image523.gif"> , Mann-Whitney (Wilcoxon) test]. Plasma toxin levels were determined by high performance liquid chromatography (HPLC). Toxin levels, expressed as peak units of area (PUA) at 340 nm, (1 PUA = 2.5x10<img SRC="http:/img/fbpe/jvat/v4n1/image523.gif"> units of absorbance/cm) were 5.5 (0.0-23.3) PUA/nl (n = 133) in the rainy season and 0.0 (0.0-1.1) PUA/nl in the dry season (n= 88, p=2x10<img SRC="http:/img/fbpe/jvat/v4n1/image523.gif"> ). The distribution of toxin concentration in both groups was also different (<img SRC="http:/img/fbpe/jvat/v4n1/image524.gif"> test, p=0.024, 7 degrees of freedom). It is then determined that toxin was not detectable in 84.1 % of the cows in the dry season (n = 88) and in only 38.3% of the cows in the rainy season (n = 133) (<img SRC="http:/img/fbpe/jvat/v4n1/image524.gif"> test, p<10<img SRC="http:/img/fbpe/jvat/v4n1/image523.gif"> ).
Abstract in English:Field bioassays were used to demonstrate that aggressive behavior of Polybia paulista (Ihering) workers is elicited by alarm pheromones present in the venom reservoirs of nest defenders and that the brood care pheromone (pupal odor) produced by the young inside the nest also plays an important defensive role. Pupal odor was extracted from the surface of pupa bodies with methanol. When bioassayed alone, the pupal odor elicited only attractiveness of workers towards the odor source, but no stinging attacks were observed. However, in the presence of alarm pheromones, the brood care pheromone potentiated the effect caused by the pupal odors, increasing the number of stinging attacks during an action of colony defense. Thus, the presence of pupae within the nest evidently not only releases brood care but also enhances the aggressiveness of workers in P. paulista colonies.
Abstract in English:The present investigation reveals the possibility of simultaneous immunization of horses with Bothrops or Crotalus snake venoms and Tetanus antigens for the production of anti-Bothrops-Tetanus or anti-Crotalus-Tetanus mixed serum, with high titers of the respective specific antibodies. Bothrops antivenoms with an average neutralizing titer of 4.16 mg venom/ml were obtained from plasma of horses with titers lower than 0.5 mg venom/ml when Tetanus antigens were not used. This suggests the existence of a synergism between Bothrops venoms and Tetanus antigens in the stimulation of the antibody response. The pooled plasma of the animals had a neutralizing titer of 21.0 mg/ml reference Bothrops venoms and 3,300 IU/ml to Tetanus antigens after purification by enzymatic digestion and ammonium sulphate precipitation. These experiments lead us to conclude that Bothrops envenomation therapy can be successfully performed using anti-Bothrops-Tetanus serum also serving as Tetanus prophylaxis. Anti-Crotalus-Tetanus serum can also be produced, although it is not of medical interest as Crotalus envenomation rarely results in local necrotizing lesions.