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At least 19 recordsLinked to original sources
PubMed1988

Enzyme-linked immunosorbant assay (ELISA) of size-selected crotalid venom antigens by Wyeth's polyvalent antivenom.

The binding of Antivenom (Crotalidae) Polyvalent to fractions from crude venoms of eight crotalid and one viperid snake, obtained by high performance size-exclusion chromatography, was determined with an indirect enzyme-linked immunosorbent assay (ELISA). Most of the large (greater than 30,000 mol. wt) molecular mass crotalid venom fractions were associated with high (greater than 0.7 absorbance units) ELISA values. Similarly, the medium (13,000-30,000 mol. wt) and small (less than 14,000 mol. wt) molecular mass crotalid venom fractions were coincident with moderate (0.3-0.7 absorbance units) and low (less than 0.3 absorbance units) ELISA levels. Some variability in this pattern was seen with individual venom fractions. A distinctly different pattern of ELISA values were observed with two rattlesnake venoms: the South American (Crotalus durissus terrificus) and Mojave desert (Crotalus scutulatus scutulatus) rattlesnakes. The elution profile from these venoms showed a progression of low to moderate ELISA values within the large molecular mass fractions. This pattern was followed by a decline to low ELISA values throughout the remainder of the elution profile. When saw scaled viper (Echis carinatus leucogaster) venom fractions were tested, only background ELISA values were detected with antivenom. Similarly, background ELISA values were associated with the small molecular mass fractions of all venoms tested. In addition, the elution position for the basic peptides of southern Pacific (Crotalus viridis helleri) and timber (Crotalus h. horridus) rattlesnake venoms showed minimal ELISA values. These data support the view that except for the venom of C. durissus terrificus and C. s. scutulatus, most antivenom antibodies bind large (greater than 30,000 mol. wt) venom fractions. Thus, antivenom contains minimal levels of antibodies to the basic peptides in these venoms.

Animals↗
PubMed1994

Inhibition of the myotoxic and hemorrhagic activities of crotalid venoms by Eclipta prostrata (Asteraceae) extracts and constituents.

The antimyotoxic and antihemorrhagic effects of Eclipta prostrata (EP) and three of its constituents (wedelolactone, WE; stigmaterol, ST; and sitosterol, SI) were investigated. The myotoxicity of crotalid venoms (Bothrops jararaca, Bothrops jararacussu and Lachesis muta), purified myotoxins (bothropstoxin, BthTX; bothropasin; and crotoxin), and polylysine was quantified in vitro by the release rate of creatine kinase (CK) from rat or mouse extensor digitorum muscles, and in vivo by the plasma CK activity in mice. The in vitro myotoxicity of the crotalid venoms and myotoxins was neutralized by simultaneous exposure of the muscles to an aqueous extract of EP or to WE. ST and SI were less effective than WE, but interacted synergistically with it. Both the EP extract and WE failed to neutralize the in vitro myotoxic effects of polylysine. The in vivo myotoxicity of venoms and myotoxins was neutralized by their preincubation with the EP extract or WE. Intravenous administration of the plant extract or WE attenuated the increase in plasma CK activity induced by subsequent intramuscular injections of the crotalid venoms or the myotoxins. EP and WE inhibited the hemorrhagic effect of B. jararaca venom, as well as the phospholipase A2 activity of crotoxin and the proteolytic activity of B. jararaca venom. The data provide direct evidence for antimyotoxic and antihemorrhagic effects of EP and WE against the crotalid venoms responsible for most cases of envenomation by snakebites in Brazil. These effects are interpreted as consequences of antiproteolytic and antiphospholipase A2 activities of EP and its constituents.

Animals↗
PubMed1996

[Neuromuscular action of crotalid venoms: preliminary data].

We studied 6 patients and 2 dogs that have been bitten by South American rattlesnake Crotalus durissus terrificus and one rabbit inoculated with crotalid venom. We analyzed sensory and motor peripheral nerve conduction, repetitive stimulation for studying neuromuscular transmission and electromyographies. Muscle biopsies were processed by histochemistry. All patients had peripheral mononeuropathy of the closest sensitive nerve to the area of snakebite. The neuromuscular transmission alterations were minimal. Muscle histochemistry of 4 patients, 2 dogs and 1 rabbit showed findings of mitochondrial myopathy. The majority of authors admit that crotalid venom causes myastenic syndrome. Our findings suggest that palpebral ptosis, myastenic facies and muscular weakness observed after crotalid poisoning are, probably, due to transient and reversible mitochondrial myopathy. As far as we know, this is the first report on the ability of the venom of this rattlesnake to cause local sensitive mononeuropathy and the first muscle histochemistry showing mitochondrial myopathy in humans poisoned by crotalid venom.

Animals↗
PubMed1991

Neutralization of kinin-releasing enzymes of crotalid venoms by monospecific and polyspecific antivenoms.

The amounts of kinin-releasing enzymes in the venoms of Crotalus atrox, Crotalus adamanteus, Crotalus scutulatus scutulatus and Agkistrodon piscivorus piscivorus were measured by determining the amounts of kinin released from a sheep kininogen substrate by means of a specific radioimmunoassay. Four monospecific and two commercial polyspecific antivenom IgG samples were tested for their ability to reduce the kinin-releasing activities of the four crotalid venoms measured in vitro. All of the antivenom IgG samples were able to neutralize venom kininogenase activity to varying extents. On of the commercial polyspecific antivenoms was of equal or higher potency than the corresponding monospecific antivenoms for three of the venoms tested, indicating a high degree of cross-neutralization. F(ab')2 and especially Fab fragments of that polyspecific antivenom IgG were also effective in reducing the kinin-releasing activities of the four crotalid venoms.

Animals↗
PubMed1997

Affinity-purified, mixed monospecific crotalid antivenom ovine Fab for the treatment of crotalid venom poisoning.

SUBJECT OBJECTIVE: To test the efficacy and safety of a new antivenom, affinity-purified, mixed monospecific crotalid antivenom ovine Fab, in human subjects with minimal or moderate crotalid envenomation. METHODS: We conducted a prospective multicenter clinical trial of 11 patients 10 years or older with progressive manifestations after mild to moderate crotalid snakebite. After giving their consent, subjects received four to eight vials of study drug and were then repeatedly examined over 48 hours and at 7 and 14 days after discharge. Each patient's clinical condition was evaluated serially with the use of a validated severity score, as well as on the basis of the investigator's assessment. RESULTS: In all 11 subjects to the antivenom was judged by the investigator to have had a beneficial response. The severity score for each patient remained the same or decreased over the first 4 hours. However, two subjects demonstrated worsened condition 12 to 15 hours after antivenom administration. In no subject did an allergic reaction develop. CONCLUSION: In this patient group, affinity-purified, mixed monospecific crotalid antivenom ovine Fab was associated with a halt of progressive crotalid venom poisoning. Initial safety data are promising but must be addressed further in subsequent studies.

Adolescent↗
PubMed1986

Antigenic relationships between Mojave toxin subunits, Mojave toxin and some crotalid venoms.

Immunochemical responses of a number of pit viper venoms to antibodies derived separately from the acidic and basic subunits were investigated by enzyme linked immunosorbent assay (ELISA) and Ouchterlony immunodiffusion. The polyclonal antisera to the basic subunit were generated in rabbits, whereas mouse hybridoma cell cultures were used to produce antibodies to the acidic subunit. The immunochemical response of a venom correlated well with published values for LD50 dose for the test venom. Many venoms that elicited a positive response with antiserum to the basic subunit also reacted strongly with the hybridoma derived antibodies to the acidic subunit. The data support the conclusion that crotalid venoms which are more lethal have in common a potent venom component that is immunochemically related to Mojave toxin.

Animals↗
PubMed1999

Neutralization of edema, hemorrhage and myonecrosis induced by North American crotalid venoms in simulated first-aid treatments.

Venoms of the broad-banded copperhead (Agkistrodon contortrix laticinctus, ACL) and the prairie rattlesnake (Crotalus viridis viridis, CVV), like other crotalid venoms, cause severe local tissue damage such as edema, hemorrhage and myonecrosis. Antivenom therapy is not very effective in neutralizing this local tissue damage, and such observations support the need for an effective first-aid regimen aimed at minimizing local tissue reactions. Some of the local tissue damage induced by these venoms is due to phospholipase A2 myotoxins, and since para-bromophenacyl bromide (p-BPB), an inhibitor of PLA2 catalytic activity, has been shown to inhibit the myotoxic action of two PLA2 myotoxins, we hypothesized that this compound would inhibit part of the myotoxic activity of these crude venoms. For in vitro neutralization experiments, venoms were mixed with combinations of either p-BPB, antivenom or both prior to injection into the muscles of the lower hindlimb of mice. For in vivo neutralization experiments, mice were injected with venom followed by either topical DMSO containing p-BPB or intramuscular injection with saline containing p-BPB. A final set of mice received these same injections followed by i.p. infusions of antivenom to simulate experimental first-aid followed by hospital treatment. In the in vitro neutralization tests, edema was significantly reduced when both antagonists were used together, and there was a highly significant neutralization of ACL- and CVV-generated myonecrosis. In the in vivo neutralization experiments, hemorrhage was significantly reduced when injection of ACL venom was followed by topical DMSO-p-BPB, and myonecrosis was reduced when injection of ACL venom was followed by intramuscular injection of saline-p-BPB. Antivenom significantly reduced edema, hemorrhage and myonecrosis induced by CVV venom, but reduced only myonecrosis induced by ACL venom. Taken together, these results suggest a role for pBPB in the first-aid treatment of snakebite especially when followed by hospital treatment with antivenom.

Acetophenones↗
PubMed1991

Antibacterial activity of crotalid venoms against oral snake flora and other clinical bacteria.

Despite heavy oral and fang contamination of crotalid species with a wide variety of potentially pathogenic bacteria, crotalid envenomation is associated with a low incidence of bacterial infection. Minimal inhibitory and bactericidal concentrations of venoms from three crotalid species were determined against six aerobic and eight anaerobic reference and oral crotalid microorganisms. All anaerobic isolates were resistant to greater than 20,480 micrograms/ml, whereas variable activity (range, 5-20,480 micrograms/ml) was observed for aerobic strains. Further studies against other aerobic clinical isolates demonstrated that venom had the greatest activity (MIC, less than or equal to 80 micrograms/ml) against staphylococci, Pseudomonas aeruginosa, and Enterobacter, Citrobacter, Proteus, and Morganella species. Inhibitory activity was lost with prolonged incubation for many gram-negative species. Crotalid venoms are broadly active against aerobic gram-negative and -positive bacteria. This activity may play a role in the low incidence of infection after envenomation injuries.

Animals↗
PubMed1982

[Resistance of Crotalus durissus terrificus and Bothrops neuwiedii to the neurotoxicity of massive quantities of Crotalid venom].

The antitoxic potency of crude Crotalus durissus terrificus serum against crotalic venom is similar to that of a standard horse anticrotalic serum in protecting mice against 4 LD50, while the potency of Bothrops neuwiedii serum is 20% of the latter. Failure to form precipitin lines in immunodiffusion tests suggests that the antitoxic factors present in the sera from both species are not immunoglobulins. It is, therefore, probable that crotoxin is not neutralized by an antigen-antibody reaction, but rather by formation of inactive complexes with specific serum components. Resistance to the venom is not reciprocal, since specimens of C. d. terrificus die after the injection of similar amounts of B. neuwiedii venom, which are tolerated by the homologous species.

Animals↗
PubMed2000

California ground squirrel (Spermophilus beecheyi) blood sera inhibits crotalid venom proteolytic activity.

Some California ground squirrels (Spermophilus beecheyi) show limited necrosis following envenomation by northern Pacific rattlesnakes (Crotalus viridis oreganus). This study demonstrates that S. beecheyi blood sera inhibits venom proteases. Sera from rattlesnake-abundant habitats inhibited C. v. oreganus venom more effectively than venom from two allopatric rattlesnake species, C. v. viridis and C. atrox, suggesting evolutionary specialization. The pattern of inhibition among squirrel populations corresponds best with history of rattlesnake predation, in contrast to current rattlesnake density.

Animals↗
PubMed2005

Crotalid venom vascular endothelial growth factors has preferential affinity for VEGFR-1. Characterization of Protobothrops mucrosquamatus venom VEGF.

Pm-VEGF, a novel member ofVEGF family from the venom gland of Taiwan habu (Protobothrops mucrosquamatu), is a disulfide-linked homodimer with 119 amino acid residues. Recombinant fusion Pm-VEGF was expressed in Escherichia coli, purified and refolded. Surface plasmon resonance was used to determine its binding kinetics toVEGF-receptors (VEGFR). Relative to human VEGF165, the binding affinity of Pm-VEGF to the VEGFR-1 was 1.7-fold higher while affinity to the VEGFR-2 was 17-fold lower. But it did not bind the VEGFR-3 or neuropilin-1. Pm-VEGF promoted the proliferation and tissue factor production of endothelial cells, the neovascularization in the chicken chorioallantoic membrane, and increased vascular permeability. It also stimulated tissue-factor production and human monocyte chemotaxis, in accord with its specificity for VEGFR-1. Structural comparison among VEGF-proteins from various viper venoms revealed that the two subfamilies of vipers (Crotalinae and Viperinae) have evolved with distinct receptor-specificities for VEGFR-1 and VEGFR-2, respectively. Discussion on structure-activity relationships of the VEGFs further provided insight into residues important for the receptor-binding and specificities.

Amino Acid Sequence↗
PubMed1986

Isolation and characterization of myotoxic phospholipases A2 from crotalid venoms.

Phospholipases A2 producing myonecrosis when injected i.m. into mice were isolated from venoms of Trimeresurus flavoviridis, Agkistrodon bilineatus, A. c. contortrix, A. c. mokeson, A. p. piscivorus and Bothrops asper by gels filtration on Sephadex G-75 followed by ion-exchange chromatography on CM-cellulose. They are basic enzymes with molecular weights between 14,000 and 15,000 containing 120-129 amino acid residues and exhibit relatively low enzymatic activity when tested on egg yolk suspension. Local myonecrosis is induced even at doses of 1.25 micrograms per mouse.

Amino Acids↗
PubMed1984

Production of a monoclonal antibody against hemorrhagic activity of Crotalus atrox (western diamondback rattlesnake) venom.

Crotalid venoms have cytotoxic properties which could be useful in medical research. Crotalus atrox venom-hyperimmunized mouse spleen cells were fused with SP2/0 myeloma cells. Forty-one wells containing the hybridoma cells were positive for C. atrox venom, as determined by the enzyme linked immunosorbent assay (ELISA). Cell line 1-e12 was cloned and used to produce ascites tumors in BALB/c mice. The monoclonal antibody produced by cloned and subcultured 1-e12 cells reacted with both C. atrox venom and six other venoms in the ELISA and neutralized the hemorrhagic activity of crude C. atrox venom. A series of monoclonal antibodies could be used in studying the nature of snake venoms.

Animals↗