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Afalcytin, a proteinase with caseinolytic, arginine-esterase and amidase activities, was purified from the venom of Cprustes cerustes (horned viper) in two steps by gel filtration through Sephadex '375, then HPLC on carboxymethyl-cellulose. AfaBcytin has an isoelectric point of 6.25. and consists of two subunits, m and /], which have the same apparent molecular mass (40000) and are indistinguishable in the absence of reduction orkand deglycosylation. Subunit /) is constituted of two disulfide-linked polypeptidic chains, , O and f . The respective apparent molecular inass of the chains are 43000 (u), 35500 (/)) and 10200 (p') as determined by SDS/PAGE under reducing conditions. Both chains a and / l are N-glycosylated. The two chains have the same N-terminal sequence (20 residues) which is similar to those of other proteinases from snake venom. Susceptibility of afalcytin to diisopropyl fluorophosphate and benzamidine indicates the presence of a serine and an aspartic (or glutamic) acid residues in the catalytic site.Ca'+ appears to be required for structural cohesion of the afaBcytin molecule. Afalcytin exhibits apfibrinogenase and rx-fibrinase properties. It replaces missing factors VIII and IX in deficient plasmas, and activates purified human factor X into factor Xa. It releases serotonin from platelets and directly aggregates human (but not rabbit) blood platelets. Despite its thrombin-like characteristics, however, afalcytin is not inhibited by plasmatic thrombin inhibitors. The procoagulant properties of afalcytin therefore have potential clinical applications.

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An epidemiological and biological survey of scorpion envenomation was conducted in Algeria. Analysis of 182 medical files showed that 70% of the patients were stung by Androctonus australis. Most accidents occurred during the morning (40%) or the evening (30%). Two-thirds of the patients reached a hospital 1 hour after being stung. Their clinical symptoms classified 78% of them as Grade I (mild envenomation) and 17% of them as Grade II (moderate envenomation) on admission to hospital. No severe envenomation (Grade III) was reported. Most patients were treated with antivenom by the intramuscular route. Blood samples were collected before and after antivenom immunotherapy. A good correlation was observed between the grade of envenomation on admission and the blood venom concentrations measured by ELISA. The venom concentration decreased as function of the interval between the sting and blood collection (t1/2 = 2 h). Intramuscular injection of 10 ml of antivenom did not efficiently neutralize scorpion venom. Inflammation was followed by measuring IL6 concentration. IL6 peaked 1 h after scorpion envenomation. This study shows that optimization of the administration of antivenom is required to achieve clinical efficiency. In particular, intravenous injection of a larger dose of a more potent antivenom should be considered.