Abstract in English:Lethal Toxin Neutralizing Factor (N-LTNF), MW 63.0 kDa, was isolated from opossum serum. After trypsin digestion, the active domain of N-LTNF was isolated and sequenced. The synthetic peptide consisting of ten amino acids was designated as LT-10. N-LTNF and LT-10 inhibited the lethality of animal, plant and bacteria toxins when tested on mice non-immunologically. The antibodies against N-LTNF and LT-10 only reacted immunologically with toxins and not with non-toxic substances. Anti-LTNF and anti-LT-10 reacted immunologically by ELISA test with toxins that were not detected by mouse test, such as cholera toxin and digoxin. Anti-LTNF and anti-LT-10 failed to react immunologically with non-toxic substances, such as nerve growth factor and collagen. Currently, mouse bioassay is in use for toxin detection and assay. Binding affinity of IgG from anti-LT-10 showed a linear relationship with mouse bioassay by ELISA detection limit to some toxins only. This may be due to the fact that anti-LTNF and anti-LT-10 detected the toxins that were not lethal to mouse. Thus, anti-LTNF and anti-LT-10 can be useful in assaying toxins as an alternative to mouse bioassay.
Abstract in English:Bothrops jararacussu venom and its major toxin bothropstoxin-I (BthTX-I) possess myotoxic and neurotoxic properties. The efficacy of a rabbit antivenom raised against B. jararacussu venom in the neutralization of physiological, biochemical, and morphological changes induced by the venom and its major toxin BthTX-I was studied in mouse isolated phrenic nerve-diaphragm (PND) and extensor digitorum longus (EDL) preparations. The times required for 50% neuromuscular blockade in PND and EDL preparations for venom were 70+11.5 (S.E.M., n=5) min and 58+8 (n=16) (50 mu g/mL), and for BthTX-I 31+6 (n=3) min and 30+3 (n=5) min (20 mu g/mL), respectively. After 120 min incubation, creatine kinase (CK) concentrations in solution containing the EDL preparations were 3464+346 U/L after exposure to venom (50 mu g/mL, n=5) and 3422+135 U/L to BthTX-I (20mu g/mL, n=4), respectively. Rabbit antivenom dose-dependently neutralized venom and toxin-induced neuromuscular blockade in both preparations and effectively prevented venom and toxin-induced CK release from EDL. Histological analysis showed that rabbit antivenom neutralized morphological damage caused by B. jararacussu venom and BthTX-I in EDL preparations. These results indicate that rabbit antivenom effectively neutralized the biological activities of B. jararacussu venom and BthTX-I.
Abstract in English:Propolis has been the subject of recent scientific investigation due to its biological properties, such as antibiotic, antiinflammatory, anesthetic, healing, immunomodulatory, antioxidant, and carcinostatic. The purpose of this study was to analyze the biochemical profile of propolis-treated rats to observe whether propolis might lead to side effects after administration. Evaluation of total protein, glucose, urea, creatinine, triglycerides, cholesterol, and HDL-cholesterol concentrations and determination of aminotransferases (AST and ALT) and lactic dehydrogenase (LDH) in propolis-treated rat serum were performed. The seasonal effect on propolis activity was also analyzed, considering the biochemical variables evaluated. The lack of clinically important changes in seric biochemical variables is probably because propolis showed no biological side effects under these conditions. A possible seasonal effect on the biochemical determinations was not observed.
Abstract in English:Pharmacological substances such as adenosine deaminase (ADA), collagen, histamine, IgE, myoglobin, and nerve growth factor (NGF) are endogenously present in animals. Research from this laboratory reported decreased levels of ADA, histamine, IgE, and NGF in organs of mice injected with sub-lethal doses of cobra venom. The goal of this research is to observe the levels of ADA, collagen, histamine, IgE, myoglobin, and NGF in certain organs of mice injected with venom from the bee Apis mellifera. Adult Balb/c female mice IM injected with half lethal dose of bee venom were sacrificed after 2 and 8 hours for removal of organs. The homogenates of the organs were assayed by ELISA for ADA, collagen, histamine, IgE, myoglobin, and NGF using respective antisera. Organs from mice injected with PBS were used as controls. It was observed that there were decreased levels of ADA, collagen, histamine, IgE, myoglobin, and NGF in certain organs after 2 h and tremendous decrease after 8 h. This is the first report showing the pharmacokinetics of ADA, collagen, histamine, IgE, myoglobin, and NGF as consequence of honeybee envenomation.
Abstract in English:Aurelia aurita is a scyphozoan, abundant in the Mexican Caribbean during summer. Although usually innocuous, there is evidence of it causing harm to humans. This work investigates the biological activities of crude and fractionated extracts of A. aurita. Live specimens were collected between July and September 1999 from the Mexican Caribbean. The tentacular margin was dissected immediately and frozen at -50ºC. A nematocyst suspension was prepared, discharged, and the supernatants lyophilized. Hemolytic assay was performed with lyophilized crude extract on bovine, sheep, and human red blood cells. Erythrocyte sensitivity to the toxin was ranked in descending order: human, sheep, and bovine. Toxic activity on Artemia nauplii was evaluated using the same crude extract for different exposure periods (3, 5, and 10 hours); only 48 and 72 hour old Artemia nauplii showed 50% mortality. Partial toxin purification was completed by sequential liquid chromatography using three gels (Sephadex G-200, DEAE Sephadex A-50, and Sephadex G-100). Intramuscular neuroactivity was detected in the crab Ocypode quadrata for two partially purified fractions. These fractions were found to have molecular weight components of 66 and 45 kDa, respectively.
Abstract in English:The search for snake venom antitumor efficacy has attracted the interest of scientists since the beginning of last century. Snake venom possesses a wide spectrum of biological activities. In this study, we evaluated the effect of Echis coloratus crude venom on the evolution of Ehrlich ascites carcinoma cells (EAC). Normal and EAC-bearing mice were treated with 0.2 mg/kg body weight of crude venom. Crude venom was seen to suppress tumor growth by significantly decreasing EAC cell count and cell viability (p<0.01). There was also a significant increase in survival time of the venom-treated tumor-bearing mice (52.3%, p<0.05) in comparison to the non-treated tumor-bearing counterparts. The study of venom effect and/or tumor inoculation on some important biochemical parameters and enzyme activities showed that the expected venom toxic effect disappeared due to the low (sublethal) dose; treatment of the tumor-bearing mice with this low dose could correct and restore biochemical parameters to normal levels which had been altered due to tumor growth. It can be concluded that Echis coloratus crude venom antitumor efficiency exceeded or camouflaged its toxic effect.
Abstract in English:The aim of this work was to investigate antigen irradiation on crotalic antivenom and the capacity of sheep as serum producers. Twelve sheep in two groups of six were inoculated with Crotalus durissus terrificus venom. One group was inoculated with natural venom (NV) and the other with Cobalt 60 gamma-irradiated venom (IrV). Three antigen doses were given to the animals at monthly intervals for immunization. The toxic activity of the venom was assessed by LD50 determination in mice. Blood samples were collected weekly analyses of serum neutralization capacity and potency. At the end of the experiment, the animals were challenged with a LD50 for sheep showed no signs of envenoming. These results showed that toxicity of the irradiated venom was 4.4 times less than the natural venom. The sera from the irradiated group neutralized LD50 14.6 times, and the sera from the natural group 4.4 times. Sera from the irradiated group were five times more potent. The two groups did not present clinical alterations. The results of this study show the potential for using sheep in crotalic antivenom production. The use of irradiated venom in sheep immunization induces a powerful and lasting humoral immune response shown by both the in vitro neutralization and potency tests and by the indirect ELISA antibody level detection technique.