Toxicon : official journal of the International Society on Toxinology
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The effects of crotapotin (a non-toxic and non-enzymatic acid polypeptide naturally complexed with phospholipase A2) and heparin on rat paw edema induced by different secretory phospholipases A2 (sPLA2) have been investigated. The ability of crotapotin to affect the enzymatic activity of the sPLA2(s) have also been evaluated. Secretory PLA2(s) obtained from both snake (Naja naja, Naja mocambique mocambique, Crotalus adamanteus and Crotalus durissus terrificus) and bee (Apis mellifera) venoms as well as that from bovine pancreas were used in this study. ⋯ The measurement of the in vitro phospholipasic activity revealed that crotapotin inhibited by 60-70% the enzymatic activities of PLA2(s) from Crotalus adamanteus, Naja mocambique mocambique, Apis mellifera venoms and bovine pancreas. Our results suggest that despite the great homology between the various types of sPLA2 they interact with crotapotin on cell surfaces in different ways leading to either inhibition or potentiation of the paw oedema by a mechanism unrelated to their enzymatic activities. Since heparin reduced paw oedema induced by PLA2 from Naja mocambique mocambique venom it is likely that this sPLA2 is similar to the novel heparin-sensitive PLA2 found in mast cells.
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One hundred and forty-seven cases of envenomed children under 15 years old presenting local and general symptoms without failure in vital functions (clinical grade II) or presenting serious general symptoms with failure in vital functions (clinical grade III) were collected during the summer seasons of 1993-1997. They were classified in six groups according to the use or not of antivenom, the route and the frequency of antivenom administration. The determination, by a sensitive ELISA, of blood venom concentration before and until 6 h after antivenom therapy, allowed the establishment of the venom toxicokinetic curve for each group. ⋯ However, the same amount of antivenom administered by intravenous route clear rapidly the blood free venom toxins. Also, the patient recovery time was significantly shortened. These data are in favor of intravenous application of an adequate dose of an efficient antivenom in order to treat successfully severe scorpion envenoming cases.
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Ovine antivenom prolonged survival in mice challenged with intravenous Chironex fleckeri venom over a limited dose range. Verapamil enhanced the beneficial effect of ovine antivenom. This data suggests that there may be an, as yet undefined, optimal antivenom dose for humans and that verapamil, used in combination with antivenom is an effective agent.
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In 1994 in Madagascar a woman died after eating a sardine, Herklotsichthys quadrimaculatus. Two heads removed, respectively, from a toxic and a nontoxic fish before cooking were retrieved, kept frozen, and used for toxin analysis. ⋯ The benthic dinoflagellate Ostreopsis siamensis that produces palytoxin and its analogs was inferred as the probable toxin source. This is the first study to shed light on clupeotoxism, a highly fatal form of human intoxication due to ingestion of clupeoid fish.