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PubMedDate not supplied

[Assessment of the efficacy of antivenom injection at the site of the intramuscular inoculation of Bothrops jararaca venom: experimental study in mice].

The 50% effective intraperitoneal (ip) dose of Bothrops jararaca antivenom (ED50) was assessed in mice immediately (ED50 Oh) and thirty minutes (ED50 30') after the intramuscular (im) injection of two 50% lethal dose (LD50) of Bothrops jararaca venom. The efficacy of the antivenom injected at the venom inoculation site was assessed by the inoculation of two LD50 of the venom by im route, followed immediately (ED50 Oh) and 30 minutes later (ED50 30') by administration of the ED50 of the antivenom either entirely by the ip route or 50 percent ip plus 50 percent im, at the same inoculation site. It was shown that the ED50 30' was 3 times greater, than the ED50 Oh and that the antivenom was more protective to mice (lower death rate in 48 hours) when given entirely ip. It was concluded that, in this experimental model, a higher dose of bothropic antivenom is needed when the treatment is started lately, and that there is no benefit in its administration at the venom inoculation site.

Animals↗

PubMed1985

Renal cortical necrosis following Bothrops jararaca and B. jararacussu snake bite.

Out of 22 patients admitted to the Intensive Care Unit of the Hospital das Clínicas, Federal University of Minas Gerais, with acute renal failure following Bothrops snake bite, 7 had renal cortical necrosis. This complication was suspected when the oligoanuric phase ranged from 21 to 28 days or when the patient, in spite of having a polyuric phase, maintained elevated blood levels of urea and creatinine after the interruption of the dialysis program, and was confirmed by a kidney biopsy. Three patients died and in two of them renal cortical necrosis was found at necropsy. Four patients were discharged from the hospital and follow-up was possible in two of them who showed recovery of renal function. Vasospasm, direct nephrotoxicity of Bothrops venom and/or disseminated intravascular coagulation leading to vascular occlusion and renal ischemia are the proposed pathogenetic mechanisms to explain renal cortical necrosis following Bothrops snake bite.

Acute Kidney Injury↗

PubMed1988

Antigenic relationship of hemorrhagic factors and proteases isolated from the venoms of three species of Bothrops snakes.

By comparative studies of the immunological properties of the metalloproteins (hemorrhagic factors and proteases) isolated from the venoms of Bothrops jaracaca, Bothrops neuwiedi and Bothrops moojeni, it was found that the hemorrhagic factors contain common antigenic determinants and the proteases were immunologically distinct entities. The rabbit antisera raised for the hemorrhagic factors not only neutralized the hemorrhagic activities of the respective factors but also activities of the other hemorrhagic factors. Although the homology among these proteins are not yet known, these studies have shown that the hemorrhagic factors must have a similar partial structure which includes the catalytic hemorrhagic active site.

Animals↗

PubMed1993

Antagonism of the myotoxic effects of Bothrops jararacussu venom and bothropstoxin by polyanions.

The effects of heparin and other polyanions on the myotoxicity of Bothrops jararacussu venom and purified bothropstoxin (BthTX) were investigated. The release rate of creatine kinase (CK) from isolated extensor digitorum longus muscle and the plasma CK activity of mice were used to quantify the results. The myotoxic effects of B. jararacussu venom or BthTX were inhibited by preincubation of these agents with one of the following: a heterogeneous heparin preparation (designated 'heparin'), low mol. wt heparin (H-4500) or dextran sulfates (DS-8000 and DS-500,000). Non-sulfated dextran (D-40,000) and two chondroitin sulfates were ineffective. The antimyotoxic effects of the polyanions are ascribed to their forming inactive acid-base complexes with the basic myotoxins of Bothrops venoms. Gel-filtration experiments in Sephadex provided direct evidence for complex formation between heparin and BthTX. Intravenous (i.v.) administration of H-4500 or DS-8000 opposed the increase in plasma CK activity induced by a subsequent i.m. injection of venom or BthTX. In contrast, pretreatment with i.v. heparin or DS-500,000 enhanced the venom-induced increase in plasma CK activity. This effect was not observed (1) when the animals were treated with a polyvalent antivenom, which inhibits the coagulation and local stasis induced by Bothrops venoms, and (2) when BthTX, which has no thrombotic or hemorrhagic properties, was the myotoxic agent. The potentiation of the venom-induced increase in plasma CK activity by heparin and DS-500,000 is ascribed to improved washout of the CK released from damaged fibers, because of the anticoagulant properties of the drugs.

Animals↗

PubMed2001

Pharmacological modulation of hyperalgesia induced by Bothrops asper (terciopelo) snake venom.

The ability of Bothrops asper snake venom to cause hyperalgesia was investigated in rats, using the paw pressure test. Intraplantar injection of the venom (5-15 microg/paw) caused a dose and time-related hyperalgesia, which peaked 2h after venom injection. Bothrops asper venom-induced hyperalgesia was blocked by the bradykinin B(2) receptor antagonist HOE 140 and attenuated by dexamethasone, an inhibitor of phospholipase A(2). Inhibition of the lipoxygenase pathway by NDGA abrogated the algogenic phenomenon. The hyperalgesic response was not modified by pretreatment with indomethacin, an inhibitor of the cyclo-oxygenase pathway, by meloxicam, an inhibitor of the type 2 cyclo-oxygenase pathway, by the PAF receptor antagonist BN52021 or by anti-TNF-alpha or anti-interleukin 1 antibodies. Intraplantar injection of the venom also caused an oedematogenic response which was not modified by any of these pharmacological treatments. These results suggest that hyperalgesia induced by Bothrops asper venom is, at least partially, mediated by bradykinin, phospholipase A(2) activity and leukotrienes. Distinct mechanisms are involved in the development of hyperalgesia and oedema induced by the venom.

Animals↗

PubMed2000

Amino acid sequence of piratoxin-II, a myotoxic lys49 phospholipase A(2) homologue from Bothrops pirajai venom.

The complete amino acid sequence of the 121 amino acid residues of piratoxin II, a phospholipase A(2) like myotoxin from Bothrops pirajai venom, is reported. PrTX-II is a basic protein with a molecular mass of 13740 Da, a calculated pI of 9.03, but an experimental pI of 8.4 +/- 0.2, showing sequence similarity with other bothropic (90-99%) or non-bothropic ( approximately 80%) Lys49 PLA(2)-like myotoxins. This similarity falls to approximately 70% when this sequence is aligned with that of Asp49 PLA(2). Due to the substitution of Asp49 by Lys49 and alterations in the calcium binding loop structure, as the replacement of Gly32 by Leu32, piratoxin-II shows no PLA(2) activity when assayed on egg yolk. Piratoxin-II showed the same primary structure as piratoxin-I, except that it has Lys116 for Leu116. Despite this slightly higher basicity at the C-terminal region, piratoxin-II was shown to be less myotoxic than piratoxin-I. The change Leu --> Lys induced an alteration of the molecule surface shape and probably of the environment charge high enough to slightly decrease the myotoxic activity. When aligned with B. jararacussu bothropstoxin-I and with B. asper Basp-II, piratoxin-II revealed a single (position 132) and a quintuple (positions 17, 90, 111, 120 and 132) amino acid substitution, respectively, suggesting a common evolutionary origin for these three myotoxins.

Amino Acid Sequence↗

PubMed1983

Blood coagulation induced by Bothrops atrox venom: identification and properties of a factor X activator.

The coagulating activity of Bothrops atrox venom was investigated in vitro with purified fibrinogen, with normal plasma and with plasma deficient in various factors of the coagulation cascade. This study indicated that Bothrops atrox venom possesses a thrombin-like action caused by one or several serine proteases sensitive to DFP treatment, but that its clotting action is in fact mainly due to components insensitive to DFP which activate prothrombin and factor X (Stuart factor). We partially purified the DFP insensitive activator of factor X from Bothrops atrox venom and found it to be a protein of molecular weight 77,000. Analysis of the purified fraction by electrophoresis on polyacrylamide gel in the presence of SDS showed that it is mainly composed of one heavy polypeptide chain (65,000) and one light doublet (12 - 13,000). This activator is calcium-dependent and catalyzes in vitro the conversion of purified factor X into factor X alpha. By its molecular properties, it resembles the factor X activator from Vipera russellii venom rather than physiological activators.

Blood Coagulation↗

PubMed1989

[Pulmonary embolism and disseminated intravascular coagulation after being bitten by a Bothrops lanceolatus snake. Apropos of a case].

The authors report the case of a Bothrops lanceolatus snake bite complicated by severe pulmonary embolism a few hours after admission. This thromboembolic complication developed despite heparin therapy and was followed by disseminated intravascular coagulation (DIC). Vascular thrombosis and pulmonary embolism are rare after Bothrops lanceolatus snake bite as patients are usually hypocoagulable due to DIC. In this case, the thromboembolism was probably caused by the procoagulant effect of the thrombin-like enzymes of the snake venom which may have been injected directly into the vein of a young woman taking a contraceptive pill. A specific antivenin which has recently become available fort treatment may decrease the complications of Bothrops lanceolatus snake bite.

Adult↗

PubMedDate not supplied

[Changes in blood coagulation time in patients bitten by young and adult Bothrops jararaca snakes].

Three hundred and forty eight cases of bites by adult Bothrops jararaca (group A) were admitted to the Hospital Vital Brazil between 1975 and 1984. These cases were compared to 623 cases of bites by young snakes of the same species (group B) during the same period and at the same hospital. There was no difference between groups regarding age or time between bite and admittance to the hospital. However in group B blood incoagulability was more frequent when compared to group A. We conclude that bites caused by young Bothrops jararaca are more likely to cause blood incoagulability in humans than bites caused by adult Bothrops jararaca.

Adolescent↗

PubMed1988

Production of monovalent anti-Bothrops asper antivenom: development of immune response in horses and neutralizing ability.

A monovalent antivenom was produced by immunizing two horses with venom of the pit viper Bothrops asper (Ophidia: Viperidae). Although development of the immune response against four toxic and enzymatic activities of the venom was similar in both horses during the first two thirds of the immunization schedule, antibody response in one of the horses reached much higher levels in the last part of the immunization. Immunoelectrophoretic analysis indicates that there were precipitating antibodies in the sera of these horses during all the stages of immunization. However, immunoprecipitation did not correlate with the ability of sera to neutralize toxic activities of B. asper venom. Monovalent antivenom was more effective than the commercially available polyvalent antivenom in the neutralization of Bothrops asper venom. On the other hand, despite the fact that it neutralizes lethal and hemorrhagic activities of the venoms of Lachesia muta and Crotalus durissus durissus, it was less effective than polyvalent antivenom in these neutralizations. Moreover, it does not neutralize defibrinating activity induced by these two venoms, whereas it neutralizes this effect in the case of B. asper venom. It is proposed that monovalent antivenom may be highly effective in the case of envenomations induced by Bothrops asper venom; its use in treating accidents by L. muta and C. durissus would be indicated only if polyvalent antivenom is not available. Results also demonstrate that it is important to monitor antibody response individually in horses being immunized for antivenom production, due to the conspicuous variability in the response of different animals.

Animals↗

PubMed1979

Thrombin-like and factor X-activator components of Bothrops snake venoms.

A comparative study on the coagulant activity of snake venoms was carried out in 26 Bothrops species, using specific clotting systems for the thrombin-like and the factor X-activator activities. With only two exceptions (B. erythromelas and B. castelnaudi) all venoms showed thrombin-like activity, since they were able to clot fibrinogen directly. The absence of thrombin-like action of B. erythromelas venom is due to a fibrinogenolytic effect. Five venoms (B. atrox asper, B. bilineatus bilineatus, B. cotiara, B. fonsecai and B. itapetiningae) were unable to produce a prothrombin activator when preincubated with serum, factor V, and phospholipid. None of the venoms seems to require factors VII, VIII, IX, XII and XIII for their complete coagulant action. Direct prothrombin activation was observed in most of the Bothrops venoms, alone or combined with thrombin-like and factor X-activator activities. An anticoagulant activity was exhibited by B. castelnaudi venom, probably due to an anti-Xa action. This study points out that the coagulant activity of snake venoms varies within the same genus and must be characterized for each species. Thus, in Bothrops venoms the thrombin-like and factor X-activator components are not always associated, the coagulant effect may be related only to one of the components.

Animals↗

PubMed2000

Structural and functional characterization of BnSP-7, a Lys49 myotoxic phospholipase A(2) homologue from Bothrops neuwiedi pauloensis venom.

BnSP-7, a Lys49 myotoxic phospholipase A(2) homologue from Bothrops neuwiedi pauloensis venom, was structurally and functionally characterized. Several biological activities were assayed and compared with those of the chemically modified toxin involving specific amino acid residues. The cDNA produced from the total RNA by RT-PCR contained approximately 400 bp which codified its 121 amino acid residues with a calculated pI and molecular weight of 8.9 and 13,727, respectively. Its amino acid sequence showed strong similarities with several Lys49 phospholipase A(2) homologues from other Bothrops sp. venoms. By affinity chromatography and gel diffusion, it was demonstrated that heparin formed a complex with BnSP-7, held at least in part by electrostatic interactions. BnSP-7 displayed bactericidal activity and promoted the blockage of the neuromuscular contraction of the chick biventer cervicis muscle. In addition to its in vivo myotoxic and edema-inducing activity, it disrupted artificial membranes. Both BnSP-7 and the crude venom released creatine kinase from the mouse gastrocnemius muscle and induced the development of a dose-dependent edema. His, Tyr, and Lys residues of the toxin were chemically modified by 4-bromophenacyl bromide (BPB), 2-nitrobenzenesulfonyl fluoride (NBSF), and acetic anhydride (AA), respectively. Cleavage of its N-terminal octapeptide was achieved with cyanogen bromide (CNBr). The bactericidal action of BnSP-7 on Escherichia coli was almost completely abolished by acetylation or cleavage of the N-terminal octapeptide. The neuromuscular effect induced by BnSP-7 was completely inhibited by heparin, BPB, acetylation, and CNBr treatment. The creatine kinase releasing and edema-inducing effects were partially inhibited by heparin or modification by BPB and almost completely abolished by acetylation or cleavage of the N-terminal octapeptide. The rupture of liposomes by BnSP-7 and crude venom was dose and temperature dependent. Incubation of BnSP-7 with EDTA did not change this effect, suggesting a Ca(2+)-independent membrane lytic activity. BnSP-7 cross-reacted with antibodies raised against B. moojeni (MjTX-II), B. jararacussu (BthTX-I), and B. asper (Basp-II) myotoxins as well as against the C-terminal peptide (residues 115-129) from Basp-II.

Amino Acid Sequence↗

PubMed1995

Screening of Bothrops snake venoms for L-amino acid oxidase activity.

Toxins, enzymes, and biologically active peptides are the main components of snake venoms from the genus Bothrops. Following the venom inoculation, the local effects are hemorrhage, edema, and myonecrosis. Nineteen different species of Brazilian Bothrops were screened for protein content and L-amino acid oxidase activity. B. cotiara, formerly found in the South of Brazil, is now threatened with extinction. Its venom contains a highly hemorrhagic fraction and, as expected from the deep yellow color of the corresponding lyophilized powder, a high L-amino acid oxidase (LAO) activity was also characterized. Flavin adenine dinucleotide (FAD) is its associate coenzyme. B. cotiara venom LAO catalyzed the oxidative deamination of several L-amino acids, and the best substrates were methionine, leucine, tryptophan, and phenylalanine, hence, its potential application for the use of biosensors for aspartame determination and for the removal of amino acids from plasma. High levels for LAO were also found in other species than B. cotiara. In addition, the technique of isoelectric focusing (IEF) was employed as a powerful tool to study the iso- or multi-enzyme distribution for LAO activity in the B. cotiara snake venom.

Amino Acid Oxidoreductases↗

PubMed2004

Pharmacological and histopathological characterization of Bothrops lanceolatus (Fer de lance) venom-induced edema.

OBJECTIVE: Bothrops venoms cause local edema, pain, hemorrhage and necrosis. In this study, we investigated the ability of Bothrops lanceolatus venom to cause edema in rat hind paws and examined the mediators involved. MATERIALS AND METHODS: Hind paw edema was induced in male Wister rats by the subplantar injection of venom (12.5-100 microg/paw) in the absence and presence of antagonists. Edema was quantified by hydroplethysmometry at 0.25, 0.5, 2, 4, 6 and 24 h post-injection and was expressed as the percentage increase relative to the contralateral (control) paw. The ability of the venom to release histamine from rat peritoneal mast cells was also assessed. RESULTS: Venom caused dose- and time-dependent edema that was maximal within 15 min but disappeared after 24 h and was accompanied by hemorrhage. Dexamethasone (1 mg/kg, s.c.), methysergide (6 mg/kg, i.p.), HOE 140 (0.6 mg/kg, i.v.) and mepyramine (6 mg/kg, i.p.) significantly ( p < 0.05) reduced edema formation, whereas indomethacin (10 mg/kg, i.p.) was ineffective. Dialysis did not affect venom-induced edema. Venom (1, 10 and 30 microg/ml) caused a concentration-dependent release of histamine (13 +/- 1%, 61.9 +/- 4.6% and 73.6 +/- 2.4%, respectively; n = 5) from rat peritoneal mast cells in vitro. Histological analysis confirmed the presence of edema, hemorrhage and neutrophil infiltration. Pretreating the venom with EDTA partially inhibited the edema and hemorrhage, but did not affect the migration of neutrophils. CONCLUSIONS: B. lanceolatus venom produced dose- and time-dependent edema in rat paws. This edema was not dependent on low molecular weight substances in the venom, but was partially dependent on a hemorrhagin and also involved the release of arachidonic acid metabolites, bradykinin, histamine and serotonin.

Adrenergic beta-Antagonists↗

PubMedDate not supplied

A randomized 'blinded' comparison of two doses of antivenom in the treatment of Bothrops envenoming in São Paulo, Brazil.

An earlier study in São Paulo state suggested that the dose for patients with mild or moderate envenoming by Bothrops snakes (mainly Bothrops jararaca) could be effectively decreased to 4 ampoules (40 mL) of Brazilian Brothrops polyspecific antivenom. The present 'blinded' study examined the lowest dose studied in the first trial (equivalent to 4 x 10 mL ampoules) and half that dose of antivenom (equivalent to 2 x 10 mL ampoules) in 2 similar groups of 170 patients who were comparable in all respects before treatment. The majority of patients showed rapid clinical improvement after treatment with either dose regimen and rapid restoration of blood coagulability and cessation of bleeding. There was no apparent difference between the 2 groups of patients in any respect. The study confirmed that, in such patients, the dose of antivenom can be decreased from 4 ampoules to 2 ampoules without reduction of therapeutic efficacy, and it is highly likely that this reduction will result in a decrease of early anaphylactic reactions caused by the antivenom.

Adolescent↗

PubMed1995

Pharmacological study of edema induced by venom of the snake Bothrops asper (terciopelo) in mice.

The effect of several drugs on the edema-forming activity of Bothrops asper venom was studied plethysmographically using the mouse foot pad assay. Bothrops asper venom induced a dose-dependent edema which developed rapidly and peaked 1 hr after envenomation. Incubation of venom with EDTA before injection resulted in a significant reduction of edema. In addition, pretreatment with prazosin, indomethacin, dexamethasone, yohimbine and mepacrine resulted in a significant reduction in edema-forming activity. However, no inhibitory effect was observed when mice were pretreated with verapamil, nordihydroguaiaretic acid, pyrilamine, cimetidine and propranolol. When drugs were administered after venom injection, only prazosin and indomethacin were effective in reducing edema. These results suggest that B. asper venom-induced edema in the mouse foot pad model is mediated, at least partially, by metalloproteinases, phospholipase A2, eicosanoid products and activation of alpha 1 and alpha 2 adrenergic receptors.

Animals↗

PubMed1994

The dynamics of local tissue damage induced by Bothrops asper snake venom and myotoxin II on the mouse cremaster muscle: an intravital and electron microscopic study.

The acute tissue damaging effects of Bothrops asper snake venom and a myotoxic Lys-49 phospholipase A2 (myotoxin II) on the mouse cremaster muscle were studied by intravital and electron microscopy. Both venom and myotoxin induced local contractions of the muscle fibres within 10-60 sec after exposure, which disappeared after 1-2 min. This observation is consistent with the hypothesis that Bothrops myotoxins act initially at the sarcolemma by affecting its permeability and allowing an influx of calcium. The venom also induced an early but transient vasoconstriction of arterioles. The development of edema was monitored using i.v. FITC-dextran as a marker. Plasma leakage started after about 2 min of exposure to venom or myotoxin, was extensive by 4-5 min, and originated from small venules and their adjoining capillary segments. The venom induced formation of thrombi and emboli in venules, but not in arterioles. Haemorrhage appeared after 4-6 min of exposure, the bleedings always originating from capillaries and small venules. The microbleedings were explosive, appearing as rapid bursts of erythrocytes into the extravascular space, and suggesting a per rhexis type of haemorrhage. This was confirmed by electron microscopy evaluation of the same microvessels observed intravitally, which showed erythrocyte extravasation through gaps in damaged endothelial cells. Other phenomena in the microcirculation included blood-flow disturbances, crenation and sphering of erythrocytes, and stasis with dense packing of cells in capillary networks. Muscle necrosis, caused by either venom or myotoxin, started 3-4 min after application. The first sign of damage in the fibres was the development of a narrow, transverse band with local loss of striation. This was followed by slow retraction of myofibrils until there was a complete transverse rupture of the fibre. This process was often repeated along the same fibre, leaving a row of fragments separated by spaces apparently devoid of myofibrillar material. The results confirm the rapid tissue damaging effects of B. asper venom, implying that potentially useful blocking agents must be administered early and have the ability to diffuse rapidly into the tissues.

Animals↗

PubMed1994

Reliability of the simple 20 minute whole blood clotting test (WBCT20) as an indicator of low plasma fibrinogen concentration in patients envenomed by Bothrops snakes. Butantan Institute Antivenom Study Group.

Reliability of the simple 20 minute whole blood clotting test (WBCT20) as an indicator of low plasma fibrinogen concentration in patients envenomed by Bothrops snakes. Toxicon 32, 1045-1050, 1994.--A simple whole blood clotting test (WBCT20) was assessed for its efficacy in determination of severe defibrinogenation in patients envenomed by Bothrops snakes in Brazil. There was a close relationship between the results of the WBCT20 and plasma fibrinogen levels in 69 moderately envenomed patients. The advantage of the WBCT20 over estimation of plasma fibrinogen concentrations in patients is that it is a simpler, faster and more reliable test. It is also of use in assessing the effectiveness of antivenom therapy in relation to the restoration of blood coagulability.

Animals↗