Toxicon : official journal of the International Society on Toxinology
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This review treats the general biology, taxonomy, distribution and venom apparatus of the venomous snakes of Central America. Consideration has been given to the chemistry, pharmacology and immunology of the venom, and particular attention is dispensed to the clinical problem, including the treatment, of envenomations by these reptiles.
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Several major venom allergens from different insects of the Hymenoptera order have been cloned and sequenced by different laboratories. These insects include fire ants, honey bees, hornets, yellowjackets and wasps. ⋯ Our studies in mice suggest that recombinant fragments containing regions of sequence identity of venom allergen(s) and host protein(s) show antigenic cross-reactivity. These studies lead to the hypothesis that cross-reactivity of venom allergens with host proteins promotes the immunogenicity of venom allergens in susceptible people.
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The crude venom of Pseudechis australis exhibited a dose-dependent anticoagulant action on human blood in vitro using computerized thromboelastography. Clot progress parameters (K and alpha) were affected at low dose levels which had no effect on onset of coagulation parameters (SP, R). At high dose levels there was total anticoagulant effect, but in all cases there was no evidence of fibrinolytic activity. These results generally agree with the known effects of this venom on coagulation in vivo, and further support our earlier suggestion that TEG may be a useful, one-step tool in the diagnosis and monitoring of the progress of envenomation patients.
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Despite several decades of laboratory research, many anecdotal clinical publications and successful production of antivenom, the active components of Chironex fleckeri venom and their mechanisms of toxicity remain poorly elucidated. Conflicting results of animal experiments and venom studies and the lack of controlled clinical trials necessitate caution in formulating protocols of clinical management. Of particular note are that in severe envenomation (1) clinical deterioration can occur within minutes and cardiac support must be emphasised in addition to respiratory support; (2) larger doses of antivenom may be appropriate; and (3) recommendations of therapy with verapamil and other cardioactive drugs remain controversial.
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Among poisonous mushrooms, a small number may cause serious intoxication and even fatalities in man. Humans may become symptomatic after a mushroom meal for rather different reasons: (1) ingestion of mushrooms containing toxins, (2) large amounts of mushrooms may be hard to digest, (3) immunological reactions to mushroom-derived antigens, (4) ingestion of mushrooms causing ethanol intolerance, and (5) vegetative symptoms may occur whenever a patient realizes that there might be a possibility of ingestion of a toxic mushroom after a mushroom meal. Based on the classes of toxins and their clinical symptoms, seven different types of mushroom poisoning can be distinguished: (1) phalloides, (2) orellanus, (3) gyromitra, (4) muscarine, (5) pantherina, (6) psilocybin, and (7) gastrointestinal mushroom syndrome. ⋯ Basic treatment includes administration of silibinin and penicillin G, although controlled studies on its therapeutic efficacy are still lacking. In serious phalloides syndrome, orthotopic liver transplantation has to be considered. Fortunately, the prognosis in most other mushroom poisonings is excellent.