Crotalus neutralising factor and its role in human leukocyte modulation.

Crotalus neutralising factor (CNF) is an endogenous γ-type phospholipase A2 (PLA2) inhibitor that inhibits the toxic action of crotoxin, a neurotoxin present in Crotalus durissus terrificus venom. However, its effects on the activation and modulation of immune cells, which play a major role in the development of inflammation, is not known. The objective of the present study was to assess the effects of CNF on human leukocyte modulation in vitro by analysing the following parameters: cell viability, phagocytic capacity, lipid droplet formation, reactive oxygen species production, nitric oxide production, p38 MAPK activation, and cytosolic PLA2 (cPLA2) gene expression. Neutrophils and peripheral blood mononuclear cells from healthy donors were isolated via the density gradient method, resuspended in RPMI medium, and incubated with RPMI (negative control), LPS, or PMA (positive control) or CNF (sample test) at a concentration of 50 µg/mL. Results showed that CNF was not toxic to human neutrophils after 48 and 72 h of incubation. CNF treatment induced an increase in PBMCs and neutrophil phagocytic capacity, as well as the formation of lipid droplets within these cells after 1 h of incubation. However, CNF did not induce the formation of reactive oxygen and nitric oxide species. Moreover, CNF induced p38 MAPK protein phosphorylation and cPLA2 gene expression in neutrophils. The data obtained herein showed that CNF action modulates human leukocytes, CNF activates important signalling pathways for human leukocytes, and it is pro-inflammatory. These findings also complement previous studies on CNF action on human peripheral blood leukocyte function.

Local and systemic effects caused by Crotalus durissus terrificus, Crotalus durissus collilineatus, and Crotalus durissus cascavella snake venoms in swiss mice.

INTRODUCTION: Crotalus envenomations cause serious complications and can be fatal without appropriate treatment. Venom isoforms present and inter/intraspecific variations in the venom composition can result in different symptoms presented by bites by snakes from the same species but from different geographical regions. We comparatively evaluated the local and systemic effects caused by Crotalus durissus terrificus (Cdt), C.d. collilineatus (Cdcolli), and C.d. cascavella (Cdcasc) envenomation. METHODS: Venom chromatography was performed. Proteolytic, phospholipase, and LAAO activities were analyzed. Edema, myotoxicity, hepatotoxicity, nephrotoxicity, and coagulation alterations were evaluated. RESULTS: The venom SDS-PAGE analyses found the presence of convulxin, gyroxin, crotoxin, and crotamine in Cdt and Cdcolli venoms. Crotamine was not present in the Cdcasc venom. Cdt, Cdcollli, and Cdcasc venoms had no proteolytic activity. Only Cdcasc and Cdt venoms had phospholipase activity. LAAO activity was observed in Cdcolli and Cdcasc venoms. Cdcolli and Cdcasc venoms caused 36.7% and 13.3% edema increases, respectively. Cdt venom caused a 10% edema induction compared to those by other venoms. All venoms increased TOTAL-CK, MB-CK, and LDH levels (indicating muscle injury) and ALT, AST, GGT, and ALP levels (markers of liver damage) and were able to induce a neuromuscular blockade. Urea and creatinine levels were also altered in both plasma and urine, indicating kidney damage. Only Cdcolli and Cdcasc venoms increased TAPP and TAP. CONCLUSIONS: Together, these results allow us to draw a distinction between local and systemic effects caused by Crotalus subspecies, highlighting the clinical and biochemical effects produced by their respective venoms.

Epidemiological study of snakebite cases in Brazilian Western Amazonia.

INTRODUCTION: Brazil has the largest number of snakebite cases in South America, of which the large majority is concentrated in the Midwest and North. METHODS: In this descriptive observational study, we assessed the epidemiological and clinical snakebite cases referred to the Centro de Medicina Tropical de Rondônia from September 2008 to September 2010. RESULTS: We followed up 92 cases from admission until discharge, namely 81 (88%) men and 11 (12%) women, with a mean age of 37 years, and mainly from rural areas (91.3%). The snakebites occurred while performing work activities (63%) during the Amazon rainy season (78.3%). The vast majority of individuals presented from the Porto Velho microregion (84.7%). Approximately 95.6% of the snakebites were caused by snakes of the genus Bothrops, followed by two lachetics and two elapidics cases. Surgery was performed in 10 cases (9 fasciotomies in the lower limb and 1 amputation). No deaths were reported in this study, but 4 cases (4.3%) developed sequelae in the lower limb. CONCLUSIONS: This study can contribute to a better understanding of envenomation in the state of Rondônia and thus can be useful for identifying real conditions that can increase the incidence of snakebites in this region. Moreover, the study results can serve as a basis for improving educational campaigns designed to prevent these types of snakebites, as well as for preserving snakes.

Local and systemic effects caused by Crotalus durissus terrificus, Crotalus durissus collilineatus, and Crotalus durissus cascavella snake venoms in swiss mice

Abstract INTRODUCTION: Crotalus envenomations cause serious complications and can be fatal without appropriate treatment. Venom isoforms present and inter/intraspecific variations in the venom composition can result in different symptoms presented by bites by snakes from the same species but from different geographical regions. We comparatively evaluated the local and systemic effects caused by Crotalus durissus terrificus (Cdt), C.d. collilineatus (Cdcolli), and C.d. cascavella (Cdcasc) envenomation. METHODS: Venom chromatography was performed. Proteolytic, phospholipase, and LAAO activities were analyzed. Edema, myotoxicity, hepatotoxicity, nephrotoxicity, and coagulation alterations were evaluated. RESULTS: The venom SDS-PAGE analyses found the presence of convulxin, gyroxin, crotoxin, and crotamine in Cdt and Cdcolli venoms. Crotamine was not present in the Cdcasc venom. Cdt, Cdcollli, and Cdcasc venoms had no proteolytic activity. Only Cdcasc and Cdt venoms had phospholipase activity. LAAO activity was observed in Cdcolli and Cdcasc venoms. Cdcolli and Cdcasc venoms caused 36.7% and 13.3% edema increases, respectively. Cdt venom caused a 10% edema induction compared to those by other venoms. All venoms increased TOTAL-CK, MB-CK, and LDH levels (indicating muscle injury) and ALT, AST, GGT, and ALP levels (markers of liver damage) and were able to induce a neuromuscular blockade. Urea and creatinine levels were also altered in both plasma and urine, indicating kidney damage. Only Cdcolli and Cdcasc venoms increased TAPP and TAP. CONCLUSIONS: Together, these results allow us to draw a distinction between local and systemic effects caused by Crotalus subspecies, highlighting the clinical and biochemical effects produced by their respective venoms.

Epidemiological study of snakebite cases in Brazilian Western Amazonia

Abstract INTRODUCTION Brazil has the largest number of snakebite cases in South America, of which the large majority is concentrated in the Midwest and North. METHODS In this descriptive observational study, we assessed the epidemiological and clinical snakebite cases referred to the Centro de Medicina Tropical de Rondônia from September 2008 to September 2010. RESULTS We followed up 92 cases from admission until discharge, namely 81 (88%) men and 11 (12%) women, with a mean age of 37 years, and mainly from rural areas (91.3%). The snakebites occurred while performing work activities (63%) during the Amazon rainy season (78.3%). The vast majority of individuals presented from the Porto Velho microregion (84.7%). Approximately 95.6% of the snakebites were caused by snakes of the genus Bothrops, followed by two lachetics and two elapidics cases. Surgery was performed in 10 cases (9 fasciotomies in the lower limb and 1 amputation). No deaths were reported in this study, but 4 cases (4.3%) developed sequelae in the lower limb. CONCLUSIONS This study can contribute to a better understanding of envenomation in the state of Rondônia and thus can be useful for identifying real conditions that can increase the incidence of snakebites in this region. Moreover, the study results can serve as a basis for improving educational campaigns designed to prevent these types of snakebites, as well as for preserving snakes.