[Effect of Tityus discrepans scorpion venom on global coagulation test. Preliminary studies].

Tityus discrepans (Td) scorpion venom modifies clotting times in humans. We studied the in vitro venom effect on partial thromboplastin time (PTT), prothrombin time (PT) and its direct clotting activity, using fresh human plasma and purified fibrinogen as substrates. Whole venom (WV) was fractioned with a Protein Pak 125 molecular exclusion column (0.5 mL/min, CH3COONH4 20 mM, pH 4.7). Six fractions (F1 through F6) with retention times ranging from 12.8 to 31 min were obtained. WV (78 to 625 microg/mL) and fraction F1 (10 to 42.5 microg/mL), shortened PTT; WV (700 to 1000 microg/mL) and fraction F6 (16.5 to 700 microg/mL), prolonged PTT. WV (40 to 240 microg/mL) and fraction F2 (5 to 40 microg/mL), prolonged PT. No thrombin-like activity was found with this venom on human plasma or purified fibrinogen. Td venom contains procoagulant components, able to shorten PTT. In addition, the venom contains anticoagulant components which prolong PT and PTT.