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PubMed1991

A comparative study of the biological properties of some venoms of snakes of the genus Bothrops (American lance-headed viper).

1. The hemorrhagic, procoagulant, anticoagulant, phosphodiesterase, alkaline phosphomonoesterase, 5'-nucleotidase, hyaluronidase, arginine ester hydrolase, phospholipase A, L-amino acid oxidase and protease activities of 26 samples of venoms from 13 species of Bothrops were determined, and the Sephadex G-75 gel filtration patterns for some of the venoms also examined. 2. The results show that while there are considerable individual variations in the biological activities of many of the Bothrops venoms tested, there are some common characteristics at the genus and species levels. 3. The differences in the biological properties of the Bothrops venoms tested can be used for the differentiation of most Bothrops species examined.

Animals↗

PubMed1989

Kallikrein-kinin system in the plasma of the snake Bothrops jararaca.

1. Bothrops jararaca venom (BJV) caused a fall in the carotid artery blood pressure of the anaesthetized snake. This effect was tachyphylactic and was potentiated by captopril, a kininase II inhibitor; it was partially antagonized by promethazine plus cimetidine and was not affected by atropine. 2. Similar hypotensive effects were obtained by administration of trypsin or a partially purified BJV kininogenase to the snake. 3. Incubation of Bothrops jararaca plasma (BJP) with trypsin released a substance (or substances) that produced hypotension in the snake but not in the rat; this hypotensive effect was also potentiated by captopril. 4. The trypsinised plasma contracted Bothrops jararaca isolated uterus, a pharmacological preparation weakly sensitive to bradykinin. Trypsinised plasma was inactive on pigeon oviduct and rat uterus and displayed a weak action on the guinea-pig ileum. Similar effects were observed with incubates of a fraction of BJP, containing globulins, with a partially purified BJV kininogenase. 5. Like mammalian kinins, the substance(s) was(were) dialysable, thermostable in acid but not in alkaline pH, and inactivated by chymotrypsin but not by trypsin. Its(their) inactivation by BJP or BJP kininase II was inhibited by captopril. 6. These findings strongly suggest that, besides releasing histamine, BJV or trypsin release a kininlike substance (or substances) from the snake plasma. 7. Since BJV and other kininogenases active on mammalian plasma were shown to be unable to release kinins from BJP, in experiments conducted on pharmacological preparations suitable for the assay of mammalian kinins, these data also suggest that the snake Bothrops jararaca, like birds, may have developed its own kallikrein-kinin system.

Animals↗

PubMed1990

South American snake venom proteins antigenically related to Bothrops asper myotoxins.

1. The presence of proteins antigenically related to Bothrops asper myotoxins in various snake venoms, mainly from South America, was investigated by using polyclonal and monoclonal antibodies. 2. Myotoxin-like components were detected in ten Bothrops venoms from South America, and in the venoms of Crotalus atrox (North America), Trimeresurus flavoviridis (Japan), and Micrurus alleni (Costa Rica). 3. Cross-reactive components detected in several Bothrops venoms show a common subunit of 15-16 kDa by sodium dodecyl sulphate-polyacrylamide gel electrophoresis, although significant charge variations are evident by immunoelectrophoresis. 4. It is concluded that proteins antigenically related to B. asper myotoxins are relatively common in the genus Bothrops and, in the light of findings discussed, are likely to possess myotoxic activity.

Animals↗

PubMed1997

Isolation and characterization of a myotoxic phospholipase A2 from the venom of the arboreal snake Bothriechis (Bothrops) schlegelii from Costa Rica.

A new myotoxic phospholipase A2 was isolated from the venom of the arboreal snake Bothriechis schlegelii (formerly Bothrops schlegelii) from Costa Rica, by ion-exchange chromatography on CM-Sephadex. B. schlegelii myotoxin I is a basic protein (pI > 9.3) with a subunit molecular weight of 15 kDa, which migrates as a dimer in sodium dodecyl sulfate-polyacrylamide gel electrophoresis under nonreducing conditions. This myotoxin is recognized by antibodies generated against Bothrops asper myotoxin II (a lysine-49 phospholipase A2), by both enzyme-immunoassay and gel immunodiffusion, in the latter case with a pattern of partial identity. The toxin induces rapid myonecrosis upon intramuscular injection in mice, as evidenced by the early increase in plasma creatine kinase activity and by direct intravital microscopic observation. B. schlegelii myotoxin I also induces edema in the mouse footpad assay and exerts lethal activity (LD50 approximately 2.5 microg/g) upon intravenous injection. The toxin has a low phospholipase A2 activity (4.2 microEq.mg-1.min-1) using egg yolk phospholipids as substrate. It also shows a weak anticoagulant effect in vitro. Its N-terminal sequence, SMYELGKMILLETGKNAATSYIAYG, shows 93% homology with both Bothrops asper myotoxin II and B. jararacussu bothropstoxin I, suggesting that B. schlegelii myotoxin I may be a new lysine-49 variant of this family of myotoxic phospholipases A2.

Animals↗

PubMed1994

Microbiological studies of abscesses complicating Bothrops snakebite in humans: a prospective study.

Forty patients with abscesses at the site of Bothrops bite were evaluated. Ten brought the snake responsible for the bite, Bothrops jararaca in all cases. On admission a sample was collected from each case for aerobic and anaerobic culture, and no abscesses drained spontaneously. None of the patients had received antibacterial therapy at this time. The bacteria most frequently isolated were Morganella morganii (23 patients), Providencia rettgeri (7) Enterobacter sp. (4), Escherichia coli (3), group D streptococcus (11) and Bacteroides sp. (6). All enterobacteria tested were sensitive to chloramphenicol, aminoglycosides and cefotaxime. Group D streptococci were sensitive to chloramphenicol, ampicillin and penicillin G, whereas anaerobic bacteria were sensitive to chloramphenicol and tetracycline. These results suggest that in cases of abscess formation secondary to Bothrops bite, chloramphenicol alone is a good choice, being both safe and cheap.

Abscess↗

PubMed1994

Isolation and partial characterization of an anti-bothropic complex from the serum of South American Didelphidae.

An anti-bothropic fraction (ABF) with anti-Bothrops jararaca venom activity tested in mice was isolated from the serum of some South American Didelphidae (Didelphis marsupialis, Philander opossum and Lutreolina crassicaudata) by DEAE-Sephacel chromatography. ABF from D. marsupialis was shown to be 12 times more active in protection assays on a weight basis than the serum proteins. A similar fraction obtained from Metachirus nudicaudatum serum was shown to be inactive. An anti-bothropic complex (ABC) was isolated from D. marsupialis ABF. HPLC gel permeation chromatography of ABC from D. marsupialis indicated the presence of a main peak with mol. wt of 84,000. SDS-PAGE of this ABC showed the presence of two subunits of 48,000 and 43,000. The active ABF isolated from P. opossum and L. crassicaudata also showed the presence of these subunits by SDS-PAGE. Isolation of the 48,000 mol. wt D. marsupialis subunit by HPLC-hydrophobic interaction chromatography demonstrated that the 43,000 subunit was essential for the protective action of the complex. Both subunits from D. marsupialis, P. opossum and L. crassicaudata were Western-blotted and N-terminal sequenced. No N-terminal amino acid was found for the 43,000 subunit, whereas for the 48,000 subunit a high degree of homology was found: D. marsupialis: H2N-L K A M D P T P P L W I K T E X P . ; L. crassicaudata: H2N-L K A M D P T P P L W I Q T E . . . ; P. opossum: H2N-L K A M D T T P E . . . No significant homology with known proteins was detected.

Amino Acid Sequence↗

PubMed1994

Purification of an acidic phospholipase A2 from Bothrops lanceolatus (fer de lance) venom: molecular and enzymatic properties.

The acidic phospholipase A2 from Bothrops lanceolatus venom has been purified by gel filtration on Sephadex G-50 and ion exchange chromatography on CM-cellulose. Analysis by FPLC on Mono-Q column of the purified phospholipase A2 indicated that it is a mixture of several isoenzymes. The two major isoforms consist of a single polypeptide chain with mol. wts of 14,500 and 15,000, which slightly differ in their isoelectric point (4.9 and 5.3) and amino acid composition. However, enzymatic and pharmacological properties of the various isoenzymes are identical. The phospholipase from B. lanceolatus venom is characterized by a progressive increase in the rate of hydrolysis when enzymatic activity is determined with crude egg yolk as substrate in the absence of detergent. This phenomenon, which is not observed with mixed micelles of lecithin-detergent, is not due to the presence of a phospholipase A2 inhibitor in the venom, as previously suggested by several investigators in the case of other Bothrops and Cobra venoms. It is rather a catalytic characteristics of B. lanceolatus venom phospholipase, the enzymatic activity of which depends on the physical state of phospholipids. Bothrops lanceolatus acidic phospholipase A2 is non-toxic.

Amino Acids↗

PubMed2006

Effect of calcineurin inhibitors on myotoxic activity of crotoxin and Bothrops asper phospholipase A2 myotoxins in vivo and in vitro.

Previous studies have shown that calcineurin activity plays a critical role in the myotoxic activity induced by crotoxin (CTX), a group II phospholipase A(2) (PLA(2)) with neurotoxic and myotoxic actions. In order to address whether calcineurin is also important for the activity of non-neurotoxic group II PLA(2) myotoxins we have compared the effects of calcineurin inhibition on the myotoxic capacity of CTX and the non-neurotoxic PLA(2)s, myotoxin II (Mt II) and myotoxin III (Mt III) from Bothrops asper venom. Rats were treated with cyclosporin A (CsA) or FK506, calcineurin inhibitors, and received an intramuscular injection of either CTX, Mt II or Mt III into the tibialis anterior. Animals were killed 24 h after injection of toxins. Tibialis anterior was removed and stored in liquid nitrogen. Myofibers in culture were also treated with CsA or FK506 and exposed to CTX, Mt II and Mt III. It was observed that, in contrast to CTX, CsA and FK506 do not attenuate myotoxic effects induced by both Mt II and Mt III in vivo and in vitro. The results of the present study suggest that calcineurin is not essential for the myotoxic activity of Mt II and Mt III, indicating that distinct intracellular pathways might be involved in myonecrosis induced by neurotoxic CTX and non-neurotoxic Bothrops sp. PLA(2) myotoxins. Alternatively, calcineurin dependent fast fiber type shift might render the muscle resistant to the action of CTX, without affecting its susceptibility to Bothrops sp. myotoxins.

Animals↗

PubMed2005

Evaluation of the effect of aqueous extract of Croton urucurana Baillon (Euphorbiaceae) on the hemorrhagic activity induced by the venom of Bothrops jararaca, using new techniques to quantify hemorrhagic activity in rat skin.

Aqueous extracts of Croton urucurana (Sangra D'agua), a plant popularly considered a cicatrizant, were analyzed for anti-Bothrops jararaca venom activity. The plant extracts antagonized the hemorrhagic activity of the venom and proanthocyanidins were involved in this activity. Two new methods for the quantification of hemorrhagic activity evoked by bothropic venoms were employed. The first consists of graphic computer analysis of the hemorrhagic halo evoked in rats by dorsal intradermic administration of venom. The second method involves quantification of the hemoglobin present in the hemorrhagic halo. Based on the results, we suggest that these methods, easily implemented in the laboratory routine, allow for quantification of venom-induced hemorrhagic activity. In addition, this study demonstrates that the rich extracts of proanthocyanidins are powerful inhibitors of bothropic venom metalloproteinases.

Animals↗

PubMed2005

Inhibitory effects of Piper umbellatum and Piper peltatum extracts towards myotoxic phospholipases A2 from Bothrops snake venoms: isolation of 4-nerolidylcatechol as active principle.

Phospholipases A(2) (PLA(2)) are important constituents of snake venoms, being responsible for several of their toxic actions. Extracts from plants used in folk medicine were screened for inhibition of the enzymatic activity of myotoxin I, a PLA(2) from Bothrops asper. Piper umbellatum and Piper peltatum extracts tested positive, and their fractionation resulted in the isolation of 4-nerolidylcatechol. Its inhibitory effects towards toxic activities of two Bothrops myotoxins, representing catalytically active (Asp49) and catalytically inactive (Lys49) types of group II PLA(2)s, respectively, were characterized. The enzyme activity of B. asper myotoxin I was completely inhibited by 4-nerolidylcatechol at an inhibitor:toxin ratio of 10:1 (wt/wt) with an IC50 of approximately 1mM. In addition, 4-nerolidylcatechol inhibited representatives of groups I and III of PLA(2)s. Its preincubation with Bothrops myotoxins significantly reduced their myotoxic and edema-inducing activities in animal experiments. However, when 4-nerolidylcatechol was administered in situ, immediately after toxin injection, its inhibitory ability was substantially lower or negligible. This might be explained by the rapid action of these toxins in vivo, together with the slow inactivation of PLA(2) activity observed in vitro. Electrophoretic and chromatographic analyses of myotoxins ruled out major changes in protein charge, hydrophobicity, or gross molecular mass being involved in the inhibition mechanism. Mass spectrometry determinations are consistent with the covalent modification of myotoxin by one molecule of 4-nerolidylcatechol. Finally, a novel compound was isolated from both Piper species, sharing the nerolidyl skeleton, but nevertheless not being inhibitory towards the PLA(2)s studied.

Animals↗

PubMed2004

Bothrops venom induces direct renal tubular injury: role for lipid peroxidation and prevention by antivenom.

Acute renal failure (ARF) is one of the most serious complications of Bothrops snakebites. Pathogenesis of ARF in snakebite envenomation may involve hemodynamic disturbances, immunologic reactions and direct nephrotoxicity. This study aimed at evaluating Bothrops jararaca venom direct toxicity on isolated rat renal proximal tubules (PT). PT was kept oxygenated and subjected to hypoxia (H, 15 min) and reoxygenation (R, 45 min). Bothropic antivenom effects, role of extracellular calcium and peroxide production were also evaluated. Cell injury was determined by LDH release (%) and peroxide production determined by xylenol-orange method. B. jararaca venom caused tubular injury (LDH 31.6 vs. 17.2%, P <0.05), which was prevented by simultaneous or delayed antivenom administration, but not with low extracellular calcium medium. Venom increased tubules peroxide production: 2.21 vs. 1.27 microM/mg protein (P <0.05) which was also prevented by antivenom administration. Venom toxic concentration did not enhance H/R injury. In contrast, non-toxic venom concentration afforded protection (LDH 41.3 vs. 51.5%, P <0.05). In conclusion, B. jararaca venom caused direct injury to normoxic renal tubules, but not to hypoxic/reoxygenated tubules. Tubular toxicity is independent of extracellular calcium and mediated in part by lipid peroxidation. Venom induced tubular injury was prevented by simultaneous or delayed antivenom administration.

Analysis of Variance↗

PubMed2004

A new hemorrhagic metalloprotease from Bothrops jararacussu snake venom: isolation and biochemical characterization.

A hemorrhagic metalloprotease, named BjussuMP-I, was isolated from Bothrops jararacussu snake venom by a combination of gel filtration on Sephacryl S-200 (0.01 M Tris-HCl, pH 7.6 buffer) and Phenyl Sepharose CL-4B chromatography (0.01 M Tris-HCl plus 4 M NaCl, pH 8.6 buffer, followed by a concentration gradient from 4 to 0 M NaCl at 25 degrees C in the same buffer). BjussuMP-I is a 60 kDa protein with a pI approximately 5.5, which induced hemorrhage after intradermal injection in mice, with a minimum hemorrhagic dose of 4.0 microg. The hemorrhagic activity of BjussuMP-I was totally abolished after incubation with a chelating agent (EDTA), corroborating the metal-dependency of this effect. BjussuMP-I shows proteolytic activity on casein and fibrinogen, although having an activity lower than that of crude B. jararacussu venom and the metalloprotease neuwiedase isolated from Bothrops neuwiedi snake venom. It was recognized by anti-neuwiedase antibodies, with a reaction of partial immunologic identity. BjussuMP-I also shows bactericidal activity against Escherichia coli and Staphylococcus aureus. This is the first report on the isolation and characterization of a high molecular weight hemorrhagic metalloprotease (BjussuMP-I) from B. jararacussu venom, which may play a relevant role in local and systemic bleeding which characterizes Bothrops envenomations.

Animals↗

PubMed2005

Antibodies to a fragment of the Bothrops moojenil-amino acid oxidase cross-react with snake venom components unrelated to the parent protein.

It is widely accepted that immunological cross-reactivity of snake venoms is mediated by antibodies that recognize venom components bearing either amino acid sequence homology or similar biological functions. However, here we demonstrate that polyspecific Bothrops antivenom is a source of cross-reactive antibodies that interact with venom proteins of distinctive primary structures and biological functions. The homoserine lactone derivative of the undecapeptide IQRWSLDKYAM (Ile1-Hse11), excised from the l-amino acid oxidase (LAAO) of the Bothrops moojeni venom, was the ligand of an affinity resin used to isolate specific anti-Ile1-Hse11 antibodies which were instrumental in revealing immunological cross-reactivity among unrelated venom proteins. We examined the extent of the cross-reactivity of these antibodies by probing electroblots of venoms from representative snakes of genera Bothrops, Lachesis, Crotalus and Micrurus, and by unambiguous structural characterization of the affinity-purified proteins of B. moojeni venom recovered from an agarose-anti-Ile1-Hse11 column. Our results indicate that all venoms tested had at least three reactive components toward anti-Ile1-Hse11 antibodies, among which we identified two serine proteases, one phospholipase A2 homologue, and LAAO. We hypothesize that the cross-reactivity of the anti-Ile1-Hse11 antibodies to unrelated venom proteins derives from their mechanism of antigen recognition, whereby complementarity is achieved through reciprocal conformational adaptation of the reacting molecules. Also, we believe these findings have implications both in the development of improved antivenoms and the preparation of immunochemical reagents for diagnostic and scientific investigation purposes in the field of snake venoms.

4-Butyrolactone↗

PubMed2005

Proteolytic, edematogenic and myotoxic activities of a hemorrhagic metalloproteinase isolated from Bothrops alternatus venom.

A hemorrhagic metalloproteinase has been isolated from Bothrops alternatus venom from specimens that inhabit the north-east region of Argentina. The present study aimed at evaluating the proteolytic, hemorrhagic, edematogenic and myotoxic activities of the purified metalloproteinase, in order to consider its participation on the phatophysiology of the intoxication by Bothrops alternatus venom. The hemorrhagic metalloproteinase was isolated by a combination of DEAE-Cellulose chromatography and gel filtration on Sephadex G-75. The enzyme showed a molecular mass around 55k Da, it exhibited a hemorrhagic activity with a minimal hemorrhagic dose of 1.9 microg, almost two fold minor than the whole venom (3.6 microg). The enzyme showed a weak proteolytic activity on casein (18.72 U/mg enzyme), similar to the one exhibited by the whole venom (20 U/mg venom). Besides, the ability to degrade casein could be detected by SDS-PAGE; beta-casein was the fraction that showed the higher degradation, followed by alphas(1)-casein and kappa-casein degradation. The hemorrhagic metalloproteinase rapidly hydrolysed the A alpha-chain of fibrinogen, followed by B beta-chain degradation and leaving the gamma-chain unaffected. Proteolytic activities were inhibited by EDTA whereas they were not inhibited by benzamidine and PMSF. The metalloproteinase showed several polypeptides chains after autocatalytic processing, including a chain of 28k Da, it could be the processed disintegrin-like and cysteine-rich domains. The isolated enzyme exhibited myotoxic activity with high CK levels at 6h, due to local ischemia resulting of its hemorrhagic activity, and a significant edema-inducing effect (MED=1.3 microg), corroborated both results by the histological observations of samples of gastrocnemius muscle. These findings showed that this hemorrhagic metalloproteinase, possesses high edematogenic and myotoxic activities and, in despite of exhibiting a weak proteolytic activity, it is able to degrade fibrinogen. So, this enzyme would contribute markedly to the phatophysiology of the bothropic envenomation.

Animals↗

PubMed2006

Purification and biological effects of C-type lectin isolated from Bothrops insularis venom.

Bothrops insularis is a snake from Queimada Grande Island, which is an island located about 20 miles away from the southeastern coast of Brazil. Compared to other Brazilian species of Bothrops, the toxinology of B. insularis is still poorly understood. Its C-type lectin is involved in several biological processes including anticoagulant and platelet-modulating activities. We purified the C-type lectin (BiLec) from Bothrops insularis venom and investigated its effect in the isolated kidney. BiLec was purified after two chromatographic steps; firstly, the whole venom was submitted to an HPLC molecular exclusion chromatography followed by a second purification through affinity chromatography. B. insularis lectin (BiLec) was studied as to its effect on the renal function of isolated perfused rat kidneys with the use of six Wistar rats. The concentration of 10mug/mL increased perfusion pressure (PP; control(60)=108.27+/-4.9; BiLec(60)=112.9+/-5.4 mmHg; *p<0.05) and renal vascular resistance (RVR; control(60)=5.38+/-0.51; BiLec(60)=6.01+/-0.57 mmHg; *p<0.05). The urinary flow reduced significantly at 90 and 120 min of perfusion (UF; control(120)=0.160+/-0.020; BiLec(120)=0.082+/-0.008 mL g(-1) min(-1); *p<0.05). Glomerular filtration rate (GFR; control(120)=0.697+/-0.084; BiLec(120)=0.394+/-0.063 mL g(-1) min(-1); *p<0.05) diminished only at 120 min. BiLec did not change the percentage of sodium (TNa(+)), potassium (TK(+)) and chloride tubular transport (TCl(-)). The histological alterations probably reflected direct injury on glomerular and tubular renal cells, as demonstrated by the rise in permeability of glomerular endothelial cells, revealed by the presence of a proteinaceous material in the Bowman space. We postulate that the C-type lectin B. insularis promoted its effects probably through interactions with endothelial cells or through the release of other mediators by tubular, mesangial and endothelial cells.

Amino Acid Sequence↗

PubMed2000

Characterization of beta-adrenoceptors responsible for venom production in the venom gland of the snake Bothrops jararaca.

We have shown that the stimulation of beta-adrenoceptors is an important step in venom production in the Bothrops jararaca venom gland. In the present study, the pharmacological profile of the beta-adrenoceptor present in Bothrops jararaca venom gland was characterized by radioligand binding assay and by the ability of isoprenaline to promote accumulation of cyclic AMP in dispersed secretory cells. In both cases, the venom glands were obtained from non-extracted snakes (quiescent stage) or from snakes which venom was extracted 4 days before sacrifice (venom production stimulated stage). [125I]-iodocyanopindolol ([125I]-ICYP) bound to extracted gland membranes in a concentration-dependent and saturable manner, but with low affinity. Propranolol, beta1- or beta2-selective adrenoceptors ligands displaced the [125I]-ICYP binding with low affinity, while selective beta3-adrenoceptor ligands did not displace the [125I]-ICYP binding. The displacement of [125I]-ICYP by propranolol was similar in non-extracted and extracted glands, showing the presence of beta-adrenoceptors in both stages. In dispersed secretory cells of non-extracted glands, isoprenaline (1 microM) increased the cyclic AMP production and propranolol (10 microM) was able to block this effect. On the other hand, in extracted glands, isoprenaline had no effect. The results suggest that the beta-adrenoceptors present in the Bothrops jararaca venom glands are different from those (beta1, beta2 or beta3) described in mammals, but are coupled to the Gs protein, like the known beta-adrenoceptor subtypes. Moreover, previous in vivo stimulation of venom production desensitizes the beta-adrenoceptors system and, although the receptors could be detected by binding studies, they are not coupled to the Gs protein, indicating that beta-adrenoceptors stimulation contributes to the initial steps of venom synthesis.

Adrenergic beta-1 Receptor Agonists↗

PubMed2004

Clinical trial of two antivenoms for the treatment of Bothrops and Lachesis bites in the north eastern Amazon region of Brazil.

The efficacies of specific Bothrops atrox-Lachesis and standard Bothrops-Lachesis antivenoms were compared in the north eastern Amazon region of Brazil. The main aim was to investigate whether a specific antivenom raised against the venom of B. atrox, the most important Amazon snake species from a medical point of view, was necessary for the treatment of patients in this region. Seventy-four patients with local and systemic effects of envenoming by Bothrops or Lachesis snakes were randomly allocated to receive either specific (n = 38) or standard (n = 36) antivenoms. In 46 cases (24 in the standard antivenom group, 22 in the other) the snake was identified either by enzyme immunoassay or by examination of the dead snake, as B. atrox in 45, L. muta in one. Patients were similar in all clinical and epidemiological respects before treatment. Results indicated that both antivenoms were equally effective in reversing all signs of envenoming detected both clinically and in the laboratory. Venom-induced haemostatic abnormalities were resolved within 24 h after the start of antivenom therapy in most patients. The extent of local complications, such as local skin necrosis and secondary infection, was similar in both groups. There were no deaths. The incidence of early anaphylactic reactions was 18% and 19%, respectively for specific and standard antivenoms; none was life-threatening. Measurement of serum venom concentrations by enzyme immunoassay (EIA) confirmed that both antivenoms cleared venom antigenaemia effectively. EIA also revealed that one patient had been bitten by Lachesis muta, although the clinical features in this case were not distinctive.

Adolescent↗

PubMed2001

Pharmacological characterization of the rat paw edema induced by Bothrops lanceolatus (Fer de lance) venom.

The inflammatory response induced by Bothrops lanceolatus venom (BLV) in the rat hind-paw was studied measuring paw edema. Non-heated BLV (75microg/paw) caused a marked paw edema accompanied by intense haemorrhage whereas heated venom (97 degrees C, 30s; 12.5-100microg/paw) produced a dose- and time-dependent non-haemorrhagic edema. The response with heated BLV was maximal within 15min disappearing over 24h. Heated venom was then routinely used at the dose of 75microg/paw. The prostacyclin analogue iloprost (0.1microg/paw) potentiated by 125% the venom-induced edema. The histamine H(1) receptor antagonist mepyramine (6mg/kg) or the serotonin/histamine receptor antagonist cyproheptadine (6mg/kg) partially inhibited BLV-induced edema whereas the combination of both compounds virtually abolished the edema. The lipoxygenase inhibitor BWA4C (10mg/kg), but not the cyclooxygenase inhibitor indomethacin (10mg/kg), significantly inhibited the edema (35% reduction; P<0.05). Dexamethasone (1mg/kg) also markedly (P<0.001) reduced venom-induced edema. The bradykinin B(2) receptor antagonist Hoe 140 (0.6mg/kg) reduced by 30% (P<0.05) the venom induced edema, whereas the angiotensin-converting enzyme inhibitor captopril (300microg/paw) potentiated by 42% (P<0.05) the edema. Bothrops lanceolatus antivenon (anti-BLV) reduced by 28% (P<0.05) the venom-induced edema while intravenous administration of antivenom failed to affect the edema. In conclusion, BLV-induced rat paw edema involves mast cell degranulation causing local release of histamine and serotonin, a phenomenon mediated mainly by kinins and lipoxygenase metabolites. Additionally, the use of a specific Bothrops lanceolatus antivenom, given subplantarily or intravenously, revealed to be little effective to prevent BLV-induced edema.

Animals↗