Abstract in English:Snakebites, being the major occupational hazard for farm workers, claim a large number of lives in the Indian subcontinent. During the course of medical management, identification of the biting species is given a low priority, resorting to prescription of polyvalent anti-snake venom. Whereas the World Health Organization (WHO) recommends monospecific anti-snake venom instead of polyvalent anti-snake venom. Thus, it is essential to identify the aggressor species either by a visual inspection or by the symptoms of the victim. Along with the four deadly venomous species (cobra, krait, Russell's viper, and saw-scaled viper), there are a number of other species of medical importance, whose venoms and bites have not been paid much attention. Thus, a misclassification resulting into erroneous treatment cannot be ruled out. This paper discusses the nature, constitution, and toxicity of venoms and their possible toxic effects on victims of snakebites. An attempt has also been made to categorize the distinctive symptoms due to the bites of the four major venomous species and their severity grading.
Abstract in English:Scorpionism is a common problem that occurs in tropical and subtropical countries and assumes great medical-sanitary importance due to its fatal effect on sensitive individuals, being able to lead children and aged people to death. The envenomation lethal potential is responsible for the serious cardiopulmonary alterations the scorpion toxin produces in its victims. The present research evaluated the effects of Tityus serrulatus venom on dogs, using two distinct doses: a dose that simulates natural envenomation (0.4 mg/total dose), and an experimental dose (0.25 mg/kg). General clinical signs were observed at different moments after envenomation, and specific data related to the cardiopulmonary system were evaluated by systemic arterial pressure measurement, CK-MB enzymatic activity dosage, and radiographic, electrocardiographic and echocardiographic examinations. Results demonstrated that the scorpion venom, in experimental doses, was able to cause acute and reversible cardiac injury in few days, and, in the dose that simulated natural accident, it produced clinical signs of light envenomation, such as local pain, hyperesthesia, sialorrhea, vomiting, diarrhea, sneeze and prostration.
Abstract in English:A comparative study on the sensitivity of erythrocytes from different vertebrate species (avian, mammalian and reptilian) to the hemolytic action caused by cardiotoxin isolated from Naja naja atra venom was carried out. Cardiotoxin was able to induce direct hemolysis in washed erythrocytes from several animals, except for llama. The EC50 values from hemolysis of the most sensitive (cat) and the most resistant (snake) animal varied approximately tenfold. According to the cell behavior, it was possible to characterize four types of behavior: The first was observed in cat, horse and human cells; the second in rat, rabbit and dog erythrocytes; and the third only in llama erythrocytes, which were resistant to cardiotoxin concentrations up to 300 µg/ml. Finally, avian and reptilian erythrocytes were more resistant to cardiotoxin III-induced hemolysis than those of the mammalian species.
Abstract in English:The preferred temperature of the yellow scorpion Tityus serrulatus was investigated since its dispersion is a matter of concern. Adult T. serrulatus, weighing 1.24 + 0.20 g (mean + sd) and with a standard length of 59.3 + 2.5 mm, were used. A metallic corridor (120 cm long, 5 cm large and 10 cm high) with thermal gradient ranging from 0°C to 40°C was used. Tityus serrulatus chose and stayed in temperatures ranging from 14°C to 38°C when safe conditions were offered (dark and thigmotactic stimuli). The number of animals that remained in the 11°C-20°C, 21°C-30°C, and 31°C-40°C temperature zones were 8, 8, and 9, respectively. The chi-square test (degree of freedom = 2) showed that differences were not significant (p>0.05). Some animals moved to lower temperature areas (less than 8°C) when the corridor was completely illuminated and thigmotactic stimuli were absent, which led the animals to present a torpor state. It is concluded that T. serrulatus does not select a specific environmental temperature. Associated with the capacity of temporally surviving at low temperatures, this species seems to be highly adaptable to different thermal zones.
Abstract in English:Many toxins from scorpion venoms cause neurotransmitters release by activating the autonomic system. The aim of the present work was to determine osmotic fragility of red blood cells (RBCs) and serum biochemical changes produced by the venom of Odonthobuthus doriae (O. doriae), a dangerous species of scorpion in Iran. For this study we selected 2 groups, each one containing 10 New Zealand white rabbits weighing 2 ± 0.2 kg. In vivo and in vitro osmotic fragilities as well as packed cell volume (PCV) were determined. Serum was separated and used for determination of glucose, blood urea nitrogen (BUN), creatinine, uric acid (UA), triglycerides, cholesterol, aspartate aminotransferase (AST, EC 220.127.116.11), and alanine aminotransferase (ALT, EC 18.104.22.168). Results indicate that Odonthobuthus doriae venom (0.5 mg/kg, IV) causes a significant increase (p<0.05) of serum glucose, UA, PCV, ALT, and AST. Increase was also observed in BUN, but it was not statistically significant. On the other hand a significant decrease (p<0.05) was observed in triglycerides and cholesterol levels. Increased in vivo osmotic fragility of RBCs was significant too, but in vitro osmotic fragility did not show a significant change. These results support the hypothesis that the biochemical variation caused by scorpion venom can be due to an autonomic storm and release of catecholamines.
Abstract in English:The neurotoxin purified from the venom of Bungarus caeruleus causes a neuromuscular blockade on acetylcholine-induced muscle twitch response in isolated frog rectus abdominis muscle preparation. Neuromuscular blockade produced by d-tubocurarine on acetylcholine-induced muscle twitch response in an isolated frog rectus abdominis muscle preparation was reversed to normal muscle twitch response in presence of neostigmine. Whereas the purified neurotoxin produced an irreversible neuromuscular blockade in presence of the same strength of neostigmine. As it is already known, botulinum toxin, which also brings about neuromuscular blockade, is effectively used as a drug in the treatment of painful movement disorders. Since the purified toxin also causes paralysis of the muscle, we propose its possible efficacy in the treatment of neuromuscular disorders.
Abstract in English:The aim of this paper was to evaluate the immune reconstitution of HIV-1 patients subjected to highly active antiretroviral therapy (HAART) for two years or more according to CD45RA and CD45RO cell count; determination of IL-2, IFN-gamma, IL-4, IL-10 and TNF-alpha serum levels; CD4+ T and CD8+ T lymphocyte count; and plasma viral load (VL) determination. For this purpose, a cross sectional study was carried out in the Tropical Diseases Area, Botucatu School of Medicine, São Paulo State University, UNESP, Botucatu, São Paulo, Brazil. Between June 2001 and April 2002, 37 HIV-1 infected patients were evaluated, 13 with treatment indication but untreated (G1), 9 subjected to HAART for 5-7 months (G2), and 15 treated for two years or more (G3); both treated groups used medication regularly and without failure. Forty-nine normal individuals were studied as controls (GC-1 and GC-2). There was a tendency (p<0.10) for the predominance of two nucleoside reverse transcriptase inhibitors (NRTI) associated with one non-nucleoside reverse transcriptase inhibitor (NNRTI) regimen in G2; and two NRTI associated with a protease inhibitor (PI) in G3. Statistical differences between groups were seen for CD45RA (G1<[G3=GC-2]; p<0.05) and CD45RO (G1<GC-2<G3; p<0.01) cells, and CD4+ T lymphocyte count (G1<G3; G2-intermediate; p<0.05), VL determination (G1>[G2=G3]; p<0.001), TNF-alpha serum determination ([G1>G3; G2=intermediate]>GC-1; p<0.001), IL-2 (G1<[G2=G3=GC-1]; p<0.01), IFN-gamma ([G1=GC-1]<[GC-2=G3]; p<0.001), IL-4 and IL-10 ([G1=G2=G3]>GC-1; p<0.001), serum cytokine profiles, with a higher proportion of subtype 2 in G1 and mature subtype 0 in G2 and G3 (p<0.005). There was no statistical difference for CD8+ T lymphocyte counts (G1=G2=G3; p<0.50). Consistency was seen between positive correlations of profile 1 definer cytokines (IL-2 and IFN-gamma), CD45RA and CD45RO cells, and CD4+ T lymphocyte counts and between positive correlations of profile 2 definer cytokines (IL-4 and IL-10) with TNF-alpha, and VL. The negative correlations were also consistent as they expressed the inverse of the positives. The variables with the highest number of correlations were IL-2, IFN-gamma, and VL, followed by CD45RA and CD45RO cells, and IL-10. The variables with the lowest number of correlations were CD4+ T and CD8+ T lymphocytes. The results express the partial but important immune reconstitution in HIV-1 infected individuals with the interference of HAART and the importance of cytokines especially IL-2 and IFN-gamma, and CD45RA and CD45RO cells as surrogate markers of this reconstitution.
Abstract in English:This study presents the epidemiological analysis of 20,699 reported spider bites involving the Loxosceles genus in the state of Paraná, Brazil, from 1993 to 2000. The incidence rate in the period was 290.24/100,000 inhabitants. The results show that 95.04% of the accidents occurred in two Health Regions of the state: greater metropolitan Curitiba (92.9%) and Irati (2.14%). The major incidence was recorded in greater metropolitan Curitiba (559.1/100,000). Loxosceles bites were more frequent in females (61%) than in males. Antivenin therapy was not necessary in 95.4% (19,662) of the cases. From the cases in which information about the time elapsed between the bite and medical treatment was recorded (9,679), 31.8% received treatment from 6 to 48 hours after the bite. Among the cases with severity rate recorded (12,096), 2.1% were severe, 50.4% moderate, and 47.4% mild. Seven deaths from Loxosceles bites were recorded, corresponding to a fatality rate of 0.03%.
Abstract in English:In this study we optimized an enzyme-linked immunosorbent assay (ELISA) to evaluate bothropic venom levels in biological samples. These samples were obtained by two distinct protocols. In the first one, Swiss mice were injected with 1 LD50 of Bothrops jararaca (B. jararaca) venom and 15 minutes later, animals were treated with ovine antibothropic serum. Blood and spleen homogenate samples were obtained 6 hours after antiserum therapy. Ovine antibothropic serum significantly neutralized venom levels in serum and spleen. In the second protocol, BALB/c mice were injected with 1 LD50 of bothropic venom by either intraperitoneal (IP) or intradermal (ID) route and venom levels were evaluated 1, 3 and 6 hours after, in blood, spleen homogenates and urine. Serum and splenic venom levels were significantly higher in animals envenomed by IP route comparing with animals envenomed by ID route. Higher venom levels were also detected in urine samples from animals envenomed by IP route. However, these differences were not statistically significant. These results demonstrated that the optimized ELISA was adequate to quantify venom levels in different biological samples. This assay could, therefore, substitute the in vivo neutralizing assay and also be useful to evaluate the severity of human and experimental envenomations.
Abstract in English:Snake antivenom is a specific antidote to the venom action, neutralizing the circulating venom. However, it fails to neutralize the venom fixed to target organs such as platelets, renal tubules, etc. Russell's viper venom initiates rapid coagulation in a victim by activating blood platelets, factors V, X, and anticoagulant cofactors. Activation of thrombin, resulting in formation of micro-thrombi, fibrinolysis, and a vicious cascade, sets in. Inhibition of activated platelets by aspirin (cyclooxygenase inhibitor) and clopidogrel (ADP receptor inhibitor) helps to break this vicious circle induced by Russell's venom and may initiate the natural physiological clotting mechanism. They can be utilized as an adjuvant treatment.
Abstract in English:Toxoplasmosis is a zoonosis caused by Toxoplasma gondii, a coccidian protozoan of worldwide distribution. The seroprevalence in canine population can be an alternative for measuring T. gondii urban spreading. A total of 780 blood samples from dogs were collected, during the yearly anti-rabies campaign, carried out by the Department of Veterinary Hygiene and Public Health, School of Veterinary Medicine and Animal Husbandry (FMVZ), São Paulo State University, UNESP, together with the county health authorities, in August 1999. Using Indirect Fluorescent Antibody Test (IFAT) for detecting antibodies anti-T. gondii in the sera samples, we observed that 258 dogs (33.1%) were positive. The associations between the serological results and the epidemiological variables were studied. Statistically significant differences were not found regarding sex (32.2% male and 34.3% female reactors). Dogs without a defined breed showed seropositivity statistically higher than the pedigreed group. The occurrence of infection was considered higher with age.