Production of TNF-a by primary cultures of human keratinocytes challenged with Loxosceles gaucho venom

Primary cultures of human keratinocytes were challenged with increasing doses from 10 ng/mL to 2 mg/mL of Loxosceles gaucho venom, responsible for dermonecrotic lesion in humans. TNF-a was investigated by bioassay and ELISA in the supernatant of the cultures challenged with 100 ng/mL, 500 ng/mL, 1 and 2 mg/mL of venom. TNF-a was detected by bioassay in the supernatant of cultures challenged with 100 ng/mL, after 6 h. The cytokine was detected by ELISA in the supernatant of the cells challenged with doses of l mg/mL, after 6 and 12 h. The results point out the capacity of this venom to activate the keratinocytes in primary cultures to produce TNF-a. The production of cytokines could contribute to the local inflammatory process in patients bitten by Loxosceles sp.

Immunohistochemical changes in kidney glomerular and tubular proteins caused by rattlesnake (Crotalus vegrandis) venom

Renal damage is an important cause of death in patients who have survived the early effects of severe crotalid envenomation. Extracellular matrix of renal tissue is altered by Crotalus toxin activities. The aim of this study was to describe how cytoskeletal proteins and basal membrane components undergo substantial alterations under the action of Crotalus vegrandis crude venom and its hemorrhagic fraction (Uracoina-1) in mice. To detect the proteins in question, the immunoperoxidase method with monoclonal and polyclonal antibodies was used. Cell types within renal lesions were characterized by phenotypic identification, by means of immunohistologic analysis of marker proteins using different primary antibodies against mesangial cells, endothelial cells, cytoskeletal proteins (intermediate filament), extracellular matrix and basal membranes. Samples for morphological study by standard procedures (biotin-streptavidin-peroxidase technique) using light microscopy were processed. Positive and negative controls for each antigen tested in the staining assay were included. After crude venom and hemorrhagic fraction inoculation of mice, the disappearance of cytoskeletal vimentin and desmin and collagen proteins in the kidney was observed. In extracellular matrix and basal membranes, collagen type IV from envenomed animals tends to disappear from 24 h to 120 h after venom injection.

Cardiovascular profile after intravenous injection of Africanized bee venom in awake rats

The manifestations caused by Africanized bee stings depend on the sensitivity of the victim and the toxicity of the venom. Previous studies in our laboratory have demonstrated cardiac changes and acute tubular necrosis (ATN) in the kidney of rats inoculated with Africanized bee venom (ABV). The aim of the present study was to evaluate the changes in mean arterial pressure (MAP) and heart rate (HR) over a period of 24 h after intravenous injection of ABV in awake rats. A significant reduction in basal HR as well as in basal MAP occurred immediately after ABV injection in the experimental animals. HR was back to basal level 2 min after ABV injection and remained normal during the time course of the experiment, while MAP returned to basal level 10 min later and remained at this level for the next 5 h. However, MAP presented again a significant reduction by the 7th and 8th h and returned to the basal level by the 24th h. The fall in MAP may contribute to the pathogenesis of ATN observed. The fall in MAP probably is due to several factors, in addition to the cardiac changes already demonstrated, it is possible that the components of the venom themselves or even substances released in the organism play some role in vascular beds.

A low-cost method to test cytotoxic effects of Crotalus vegrandis (Serpentes: Viperidae) venom on kidney cell cultures

The pathogenesis of the renal lesion upon envenomation by snakebite has been related to myolysis, hemolysis, hypotension and/or direct venom nephrotoxicity caused by the venom. Both primary and continuous cell culture systems provide an in vitro alternative for quantitative evaluation of the toxicity of snake venoms. Crude Crotalus vegrandis venom was fractionated by molecular exclusion chromatography. The toxicity of C. vegrandis crude venom, hemorrhagic, and neurotoxic fractions were evaluated on mouse primary renal cells and a continuous cell line of Vero cells maintained in vitro. Cells were isolated from murine renal cortex and were grown in 96 well plates with Dulbecco's Modified Essential Medium (DMEM) and challenged with crude and venom fractions. The murine renal cortex cells exhibited epithelial morphology and the majority showed smooth muscle actin determined by immune-staining. The cytotoxicity was evaluated by the tetrazolium colorimetric method. Cell viability was less for crude venom, followed by the hemorrhagic and neurotoxic fractions with a CT50 of 4.93, 18.41 and 50.22 µg/mL, respectively. The Vero cell cultures seemed to be more sensitive with a CT50 of 2.9 and 1.4 µg/mL for crude venom and the hemorrhagic peak, respectively. The results of this study show the potential of using cell culture system to evaluate venom toxicity.

Neurotoxic activity and ultrastructural changes in muscles caused by the brown widow spider Latrodectus geometricus venom

Brown widow spider (Latrodectus geometricus) venom (BrWSV) produces few local lesions and intense systemic reactions such as cramps, harsh muscle pains, nausea, vomiting and hypertension. Approximately 16 protein bands under reducing conditions and ~ 14 bands under non-reducing conditions on a 12.5% sodium dodecyl sulfate-polyacrylamide gel electrophoresis were observed. Neurotoxic clinical manifestations were confirmed in vivo, while proteolytic activity was demonstrated on gelatine film. Severe ultrastructural damages in mice skeletal muscles were observed at 3, 6, 12 and 24 h postinjection with at total of 45 µg of venom protein. Infiltration of eosinophils and ruptures of the cellular membranes were observed in the muscles along with swelling of the nuclear cover and interruption of the collagen periodicity. Altered mitochondrias and autophage vacuoles, nuclear indentation and mitochondria without cristae, slight increment of intermyofibrillar and subsarcolemic spaces and myelinic figures formation were also observed. In the capillary, endothelial membrane unfolding into the lumen was noticed; along with myelinic figures compatible with a toxic myopathy. Swollen sarcotubular systems with lysis of membrane, intense mitochondria autophagia and areas without pinocytic vesicles were observed. Swollen mitochondria surrounded by necrotic areas, myofibrillar disorganization and big vacuolas of the sarcotubular system, degenerated mitochondrium with formation of myelinic figure was seen. Glycogenosomes with small particulate, muscle type glycogen was noticed. Autophagic vacuole (autophagolysosomes) and necrotic areas were also noticed. These damages may be due to interactive effects of the multifactorial action of venom components. However, Latrodectus geometricus venom molecules may also be utilized as neuro therapeutic tools, as they affect neuronal activities with high affinity and selectivity. To our knowledge, the present study is the first ultrastructural report in the literature of muscle injuries and neurological and proteolytic activities caused by BrWSV.

Neutralization of bitis parviocula (Ethiopian mountain adder) venom by the south african institute of medical research (SAIMR) antivenom

BACKGROUND: The Ethiopian mountain adder (Bitis parviocula) is a viperid known only from a few locations in southwestern Ethiopia. METHODS: a total of 30 µg of B. arietans and B. parviocula venoms were run on a 10-20% Tricine gel. To assay lethality dose fifty (LD50), five groups of eight mice for each venom were used. Hemorrhagic activity for crude venom was tested. Fibrinogenolytic activity of crude venom was measured using (2.5 mg/mL) of fibrinogen solution and (0.03 mg/mL) of crude venom. Gelatinase activity of the venom was tested on a Kodak X-OMAT TM film. Crude venoms of B. parviocula and B. arietans were tested for their abilities to affect clotting time, clotting rate and platelet function on whole human blood. RESULTS: The (SAIMR) antivenom was confirmed in this study to neutralize the lethal activity of venom from Bitis parviocula. The ED50s of SAIMR antivenom on B. parviocula and B. arietans neutralized half of 18.2 and 66.7 mg of venom, respectively. The hemorrhagic activities (MHDs) of B. parviocula and B. arietans were 0.88 and 1.7 µg, respectively. Bitis arietans and B. parviocula venoms degradated α and β chains at different times. The γ chains remained unaffected. Bitis parviocula venom did not exhibit gelatinase activity, while B. arietans had a MGD of 6.9 µg. At 3 mg/mL, the crude venoms of B. parviocula and B. arietans did not significantly affect clotting time or clotting rate. CONCLUSIONS: The SAIMR antivenom is very effective in neutralizing the venom of B. parviocula and should be considered in treating envenomations by these snakes.

ACUTE KIDNEY INJURY CAUSED BY Crotalus AND Bothrops SNAKE VENOM: A REVIEW OF EPIDEMIOLOGY, CLINICAL MANIFESTATIONS AND TREATMENT

SUMMARY Ophidic accidents are an important public health problem due to their incidence, morbidity and mortality. An increasing number of cases have been registered in Brazil in the last few years. Several studies point to the importance of knowing the clinical complications and adequate approach in these accidents. However, knowledge about the risk factors is not enough and there are an increasing number of deaths due to these accidents in Brazil. In this context, acute kidney injury (AKI) appears as one of the main causes of death and consequences for these victims, which are mainly young males working in rural areas. Snakes of the Bothrops and Crotalus genera are the main responsible for renal involvement in ophidic accidents in South America. The present study is a literature review of AKI caused by Bothrops and Crotalus snake venom regarding diverse characteristics, emphasizing the most appropriate therapeutic approach for these cases. Recent studies have been carried out searching for complementary therapies for the treatment of ophidic accidents, including the use of lipoic acid, simvastatin and allopurinol. Some plants, such as Apocynaceae, Lamiaceae and Rubiaceae seem to have a beneficial role in the treatment of this type of envenomation. Future studies will certainly find new therapeutic measures for ophidic accidents.

A study of bacterial contamination of rattlesnake venom

The authors studied the bacterial contamination of rattlesnake venom isolated from snakes in captivity and wild snakes caught recently. The captive snakes showed a relatively high incidence of bacterial contamination of their venom.

South american rattlesnake venom: its hemolytic power

The hemolytic power of rattlesnake venom (Crotalus durissus terrificus) was Studied. A high percentage of sample with negative hemolytic power was detected when sheep red blood cells were used. A large number of venoms with hemolytic power, though with a low hemolysis percentage, were detected when liquid, recently extracted venom was used. When crystallized venom was used under the same experimental conditions, a higher percentage ofpositivityfor hemolysis was obtained. When the results obtained on agar plates were compared to those obtained in test tubes, a large number of animals with a higher percentage of hemolysis were detected, though this value was not proportional to the number of animals showing positive plate hemolysis. When the hemolytic power of these venoms was tested on human red blood cells, a large percentage of animals with venoms having a low hemolytic power was also detected. Hemolytic power was much greater when human red blood cells were tested with crystallized venom. The preparation of red blood cells also had an important effect and the use of red blood cells from defibrinated blood is recommended. We conclude that rattlesnake venom has hemolytic power that increases when the venom is crystallized. Red blood cells should be properly preparedfor the lysis reactions. We suggest that the lytic power of the venom is related to venom concentration and to the purity of its fractions.

Experimental ophitoxemia produced by the opisthoglyphous lora snake (Philodryas olfersii) venom

Several colubrid snakes produce venomous oral secretions. In this work, the venom collected from Venezuelan opisthoglyphous (rear-fanged) Philodryas olfersii snake was studied. Different proteins were present in its venom and they were characterized by 20% SDS-PAGE protein electrophoresis. The secretion exhibited proteolytic (gelatinase) activity, which was partially purified on a chromatography ionic exchange mono Q2 column. Additionally, the haemorrhagic activity of Philodryas olfersii venom on chicken embryos, mouse skin and peritoneum was demonstrated. Neurotoxic symptoms were demonstrated in mice inoculated with Philodryas olfersii venom. In conclusion, Philodryas olfersii venom showed proteolytic, haemorrhagic, and neurotoxic activities, thus increasing the interest in the high toxic action of Philodryas venom.

Primeiro registro de escorpionismo causado por Tityus adrianoi Lourenço (Scorpiones: Buthidae)

Apresentamos três casos de escorpionismo causados por Tityus adrianoi Lourenço ocorridos em Belo Horizonte e Curvelo, Minas Gerais, Brasil. O atendimento aos pacientes ocorreu no mesmo dia do acidente e em todos os casos foi relatada apenas dor local, que variou de leve a intensa, sem complicações posteriores. Os três acidentes foram classificados como leves.

Scorpionism due to Tityus neoespartanus (Scorpiones, Buthidae) in Margarita Island, northeastern Venezuela

The first two cases of scorpion envenoming caused by Tityus neoespartanus (Buthidae) are described. The accidents took place within human environments (one inside a home and the other inside a school), in the village of La Sierra, Margarita Island, State of Nueva Esparta, northeastern Venezuela. Both cases were moderately severe and developed pancreatic involvement and electrocardiographic abnormalities. This report allows inclusion of Margarita Island among the endemic areas of scorpionism in Venezuela.

Escorpionismo por Tityus pusillus Pocock, 1893 (Scorpiones; Buthidae) no Estado de Pernambuco

Apresentamos neste trabalho os primeiros relatos de acidente escorpiônico causado pela espécie Tityus pusillus (Buthidae). Os acidentes ocorreram no ambiente doméstico, na área rural situada nas cidades de Paudalho e São Lourenço da Mata, Pernambuco, Brasil. Os dois casos descritos, uma criança e uma mulher grávida, foram classificados como leve e moderado, respectivamente. Os sintomas clínicos apresentados foram distúrbios locais (dor e parestesia) e distúrbios sistêmicos (calafrios, tontura, cefaléia e vômito). Esses registros permitem incluir Tityus pusillus como uma espécie de importância médica no Brasil.

Tityus stigmurus (Thorell, 1876) (Scorpiones; Buthidae): response to chemical control and understanding of scorpionism among the population

In this study, the events following application of the insecticideDemand 2.5 concentrated solution (CS) in the field, to control Tityus stigmurus, were investigated. Data on attitudes and practices relating to scorpionism were collected using a questionnaire. During the months of May to July 2005, 69 premises were monitored on different days following insecticide treatment, focusing on scorpion frequency and mortality. According to the results, 42% of the premises showed scorpion incidence, with an average of three specimens per house. The highest incidence was recorded during the first week following the treatment. Only 7% of the specimens were found dead. Most (72%) of the population showed knowledge about prevention and control measures. Despite this, 100% of the premises presented breeding sites, mainly in debris (79.7%). These results indicate that the scorpion control method used by health agents during this investigation was not efficient, and the results suggest that the method may have had a dispersive effect on these animals.

Pediatric epidemiological aspects of scorpionism and report on fatal cases from Tityus stigmurus stings (Scorpiones: Buthidae) in State of Pernambuco, Brazil

Introduction Envenomation by scorpion stings is a major public health problem in numerous tropical countries because of its frequent incidence and potential severity. Approximately 1,900 species of scorpions are known in the world, and at least 130 of these have been described in Brazil. Methods This work reports on 3 child deaths caused by Tityus stigmurus stings and characterizes epidemiological and clinical surveys on pediatric cases of scorpionism recorded in the Centro de Assistência Toxicológica de Pernambuco (Ceatox-PE). Results Scorpion stings accounted for more than 60% of all cases recorded for venomous animals. The children were from 37 cities of the Pernambuco state and accounted for 28.8% of the victims treated for scorpion stings, with the highest incidence in the metropolitan area of Recife. Stings occurred throughout the year and slightly increased during the rainy season. Independent of the elapsed time for a prognosis, most cases showed mild symptoms. Three moderate cases that resulted in death featured cardiogenic shock and/or pulmonary edema or severe neurological symptoms. For the first time, death attributed to T. stigmurus was confirmed by the presence of the scorpion. Conclusions These results suggest that scorpionism in Pernambuco is a public health problem that needs to be monitored carefully throughout the year by the government.