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| Blood Control in the Body |
| The regulation of blood flow through the body is controlled by a system of proteins, enzymes, and blood cells. When platelets encounter areas of bleeding, they stimulate the production of thromboplastins, which convert prothrombin to thrombin. Thrombin then converts fibrinogen into fibrin, which creates the patchwork of fibrous tissues that forms a blood clot (Orians, 1983). Without an intact thrombin/fibrin system, the body will bleed uncontrollably. Hemorrhaging begins as soon as 2 minutes after a bushmaster bite. Even if the body is treated with antivenin, the affected limb could be permanently damaged by the powerful hemorrhagic factors in bushmaster venom. If left untreated, hemorrhaging can spread to the heart, lungs and small intestine (Tu, 1977). Bushmaster venom causes hemorrhaging via two pathways. |
| Metalloproteinases |
| Metalloproteinases are heavy enzymatic compounds involved in various functions in the body. They occur naturally in humans and are involved in clot formation/dissolution. The ones found in bushmaster venom have never been isolated and purified, and are therefore poorly understood. But the hemorrhagic components of these metalloproteinases seem to hydrolyze fibrinogen, inactivating it, and making it impossible for thrombin to make the necessary conversion of fibrinogen to fibrin (Sanchez, 1995). |
| Phospholipase A2 |
| Phospholipase A2 is the most powerful enzyme in bushmaster venom, and is responsible for nearly all of its deadly effects. In terms of hemorrhage, this compound acts on the capillary and artery endothelium, cleaving it, and releasing erythrocytes (red blood cells) into the intracellular space (Tu, 1977). Compounded by the fact that metalloproteinases are inhibiting clot formation, this becomes a major problem. Though the mechanism is not yet understood, phospholipase A2 is also thought to be a platelet aggregation inhibitor (Fuly, 1993). |
| *oddly, phospholipase A2 is naturally occurring in the human pancreas, but it needs a compound called deoxycholate to activate it. The phospholipase A2 in snake venom does not require activation (Tu, 1977) |
| but........ |
| It's not quite that simple. Recent studies have shown that bushmaster venom in addition to having potent hemotoxins and anti-coagulants, also contain powerful thrombin-like enzymes that aid in clot formation and blood control (Ortiz, 1993). One arising theory states that the amount of coagulant vs. anti-coagulant in bushmaster venom depends on the size of the venom injection. The issue has not been settled. |