Avalia\ue7\ue3o da DL50 e edema pulmonar induzido pelo veneno de Tityus serrulatus (Scorpiones; Buthidae) procedente da Bahia, Brasil

O escorpião Tityus serrulatus é conhecido como a espécie mais importante, do ponto de vista médico, pois é o que causa os acidentes mais graves registrados para o território brasileiro. Este trabalho trata da caracterização do veneno do escorpião T. serrulatus, através da obtenção da DL50 e determinação da capacidade em induzir edema pulmonar, em ratos. O veneno foi obtido através de estímulo elétrico. A toxicidade foi determinada através da avaliação da DL50, pelo método de Finney (1971). Os valores demonstraram a baixa toxicidade do veneno (96,16 mg/camundongo), que corresponde a 3 - 7 vezes menos tóxico que venenos de espécimes de outras regiões do Brasil. O veneno testado também não induziu edema pulmonar, avaliado através da diferença entre o peso do pulmão de animais experimentais e controle. Estes resultados demonstram uma variação do veneno de T. serrulatus e poderia explicar a ausência de óbitos e do registro de edema pulmonar nos pacientes picados nestas regiões do Estado da Bahia, Brasil

Coral snake bites (micrurus Spp.) in Brazil: a review of literature reports

In the Americas, the main representatives of the family Elapidae are coral snakes of the genus Micrurus, of which 33 species are in Brazil. They are the smallest cause of venomous snakebite in Brazil. We analyzed literature reports of coral snake bites in Brazil from 1867 to 2014, and provide a brief review of case series and reports of coral snake bites in the Americas in general. Only reports with clinical descriptions of envenomation were included. The variables recorded included identification of the offending snake, patient's age, sex, bite site, clinical manifestations, treatment, including antivenom and anticholinesterase drugs, and general evolution of the cases. 30 published reports describing bites caused by Micrurus spp. in Brazil were identified and involved 194 distinct cases. Since no information on the clinical manifestations was available in 44 cases, the analysis was restricted to 25 reports (150 cases). Most patients were from southern (61.3%; primarily Santa Catarina state, 60%) and southeastern (20%) Brazil and were male (70.7%), with a median age of 27 years (interquartile interval = 18 to 40 years). The offending snakes were described in 59 cases (M. corallinus 36, M. frontalis 12, M. lemniscatus 5, M. hemprichi 2, M. filiformis 1, M. ibiboboca 1, M. spixii 1 and M. surinamensis 1); in 22 cases only the genus (Micrurus spp.) was reported. Of the 143 cases in which the bite site was recorded, most involved the hands (46.2%) and feet (26.6%). The main clinical features were local numbness/paresthesia (52.7%), local pain (48%), palpebral ptosis (33.3%), dizziness (26.7%), blurred vision (20.7%), weakness (20%), slight local edema (16%), erythema (16%), dysphagia (14.7%), dyspnea (11.3%), inability to walk (10.7%), myalgia (9.3%), salivation (8%) and respiratory failure (4.3%). Fang marks were described in 47.3% of cases and 14% of bites were classified as asymptomatic. A slight increase in total blood creatine kinase was reported in 3 children, suggesting mild myotoxicity. Therapeutic procedures included coral snake antivenom (77.3%), anticholinesterase drugs (6%), and mechanical ventilation (3.3%). Two patients reported in 1933 developed paralysis/respiratory failure and died 6 h and 17 h post-bite. Four more deaths probably caused by coral snakes were reported (2 in 1867, 1 in 1959, 1 in 1962), but no clinical information was available. Neuromuscular blockade was the hallmark of systemic envenomation by Micrurus spp., with signs of myasthenia such as weakness and ptosis that may evolve to paralysis and respiratory failure. Local features, mainly numbness/paresthesia and pain, were frequently reported, with the pain being intense in some cases. Although myotoxicity has been detected in experimental studies with Micrurus spp. venoms, few human reports described laboratory findings compatible with myotoxicity. Most coral snake bites reported in Brazil were caused by M. corallinus and M. frontalis, with several patients showing signs of acute myasthenia. Serious complications such as paralysis with respiratory failure were observed but comparatively rare. The deaths occurred where respiratory support (mechanical ventilation) was unavailable when needed.In the Americas, the main representatives of the family Elapidae are coral snakes of the genus Micrurus, of which 33 species are in Brazil. They are the smallest cause of venomous snakebite in Brazil. We analyzed literature reports of coral snake bites in Brazil from 1867 to 2014, and provide a brief review of case series and reports of coral snake bites in the Americas in general. Only reports with clinical descriptions of envenomation were included. The variables recorded included identification of the offending snake, patient's age, sex, bite site, clinical manifestations, treatment, including antivenom and anticholinesterase drugs, and general evolution of the cases. 30 published reports describing bites caused by Micrurus spp. in Brazil were identified and involved 194 distinct cases. Since no information on the clinical manifestations was available in 44 cases, the analysis was restricted to 25 reports (150 cases). Most patients were from southern (61.3%; primarily Santa Catarina state, 60%) and southeastern (20%) Brazil and were male (70.7%), with a median age of 27 years (interquartile interval = 18 to 40 years). The offending snakes were described in 59 cases (M. corallinus 36, M. frontalis 12, M. lemniscatus 5, M. hemprichi 2, M. filiformis 1, M. ibiboboca 1, M. spixii 1 and M. surinamensis 1); in 22 cases only the genus (Micrurus spp.) was reported. Of the 143 cases in which the bite site was recorded, most involved the hands (46.2%) and feet (26.6%). The main clinical features were local numbness/paresthesia (52.7%), local pain (48%), palpebral ptosis (33.3%), dizziness (26.7%), blurred vision (20.7%), weakness (20%), slight local edema (16%), erythema (16%), dysphagia (14.7%), dyspnea (11.3%), inability to walk (10.7%), myalgia (9.3%), salivation (8%) and respiratory failure (4.3%). Fang marks were described in 47.3% of cases and 14% of bites were classified as asymptomatic. A slight increase in total blood creatine kinase was reported in 3 children, suggesting mild myotoxicity. Therapeutic procedures included coral snake antivenom (77.3%), anticholinesterase drugs (6%), and mechanical ventilation (3.3%). Two patients reported in 1933 developed paralysis/respiratory failure and died 6 h and 17 h post-bite. Four more deaths probably caused by coral snakes were reported (2 in 1867, 1 in 1959, 1 in 1962), but no clinical information was available. Neuromuscular blockade was the hallmark of systemic envenomation by Micrurus spp., with signs of myasthenia such as weakness and ptosis that may evolve to paralysis and respiratory failure. Local features, mainly numbness/paresthesia and pain, were frequently reported, with the pain being intense in some cases. Although myotoxicity has been detected in experimental studies with Micrurus spp. venoms, few human reports described laboratory findings compatible with myotoxicity. Most coral snake bites reported in Brazil were caused by M. corallinus and M. frontalis, with several patients showing signs of acute myasthenia. Serious complications such as paralysis with respiratory failure were observed but comparatively rare. The deaths occurred where respiratory support (mechanical ventilation) was unavailable when needed54322223

Coral snake bites in Brazil: a review

Coral snakes ( Micrurus spp.) are the main representatives of the family Elapidae in the Americas. We reviewed the reports of coral snake bites in Brazil from 1933 to 2014 to determine the species involved, the clinical manifestations of envenomation, the treatment used and the outcome.Methods: Twenty four reports in English or Portuguese describing case series and case reports of coral snake bites were identifi ed by searching Internet databases (EMBASE, PubMed, Scielo and LILACS), books, abstracts published in congress proceedings, academic dissertations and personal communications. Sincethree reports dealt with the same cases, subsequent analysis was restricted to 21 reports (6 articles, 9 abstracts, 3 books, 2 academic dissertations, 1 personal communication) describing 150 cases. Results: Of the 150 cases, 60% were from Santa Catarina state (southern Brazil). The snakes were brought for identification in 82 cases ( Micrurus spp. n 22, M. corallinus n 37, M. frontalis n 12, M. lemniscatus n 5, M. filiformis n 1, M. hemprichi n 2, M. surinamensis n 1, M. spixii n 1 , M. ibiboboca n 1). Of the 134 cases in which the bite site was recorded, most involved the hands (46.3%) and feet (26.1%). The main clinical features described were local numbness/paresthesia (52%), local pain (47.3%), palpebral ptosis (45.3%), blurred vision (20%), weakness (16.7%), dysphagia (14.7%), myalgia (9.3%), inability to walk (9.3%), dyspnea (8%), and salivation (8%). Fang marks were present in 45.3%, and 14.7% were classified as asymptomatic. A slight increase in total blood creatine kinase was reported in two cases (1,766 IU and 1,354 IU). Therapeutic procedures included the use of anti- Micrurus antivenom raised against M. corallinus and M. frontalis venoms (76%; F(ab ´ )2, Instituto Butantan, Brazil), anticholinesterase drugs (7.3%) and mechanical ventilation (4.7%). Two patients (reported in 1933), developed respiratory failure/paralysis and died 6 hours and 17 hours post-bite, respectively. Conclusion: Neuromuscular blockade (pre- and/or post-synaptic) is the hallmark of systemic envenomation by Micrurus spp. Systemic neurotoxic envenomation was detected in 47.3% of patients (respiratory depression in 6%), similar to data reported by Wood et al. 1 Local features, such as paresthesia and pain, were also frequently reported. The two reported deaths were described in a situation where mechanical ventilation support was unavailable. Envenomation by Micrurus spp. in Brazil is uncommon. Although many patients developed systemic neurotoxicity, few required respiratory support53428128

Cardiac effect induced by Crotalus durissus cascavella venom: morphofunctional evidence and mechanism of action

Envenoming, resulting from snake bites, is a global public health problem. The present study was undertaken to investigate the influence of Crotalus durissus cascavella (Cdcas) venom on cardiac activity and the mechanisms of action underlying its effect. To investigate the inotropic and chronotropic effects induced by Cdcas, studies were performed on the left and right atria. A series of tests were conducted to investigate whether the negative inotropic effect, induced by Cdcas, was related to cardiac damage. Cdcas venom (0.1−30 μg/mL) elicited a significant negative inotropic effect. The addition of Cdcas crude venom (7.5, 15 and 30 μg/mL) did not induce significant alterations in cell proliferation, nor in the enzymatic activity of total-CK and CKsingle bondMB. Ultrastructural evaluation demonstrated that cardiac cells from isoproterenol and Cdcas groups revealed discreet swelling and displaced intermyofibrillar mitochondria with disorganization of the cristae. No change was observed in cardiac electrical activity in perfused isolated rat hearts with Cdcas. In addition, Cdcas reduced contractility in isolated cardiomyocytes from the rat left ventricle. The negative inotropic effect of Cdcas was reduced by l-NAME (100 μM), PTIO (100 μM), ODQ (10 μM) and KT5823 (1 μM), suggesting the participation of NO/cGMP/PKG pathway due to Cdcas. In non-anesthetized rats, Cdcas induced hypotension followed by bradycardia, the latter was also observed by ECG (anesthetized animals). Our results suggest that the negative inotropic effect induced by Cdcas venom is unrelated to cardiac toxicity, at least, at the concentrations tested; and occurs through of NO/cGMP/PKG pathway, likely leading to hypotension and bradycardia when administered in vivo.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto Clodomiro Picado (ICP