ABSTRACT
All of the hemorrhagic toxins isolated to date have been shown to have proteolytic activity either using casein or dimethylcasein as a substrate. Dermonecrotic toxins are proteins which cause necrosis in the skin after intradermal injection. Several toxins have been isolated from snake venoms which cause myonecrosis in mice upon intramuscular injection. Microscopic examination of the tissue after injection of the toxins shows that they induce an initial vacuolation of skeletal muscle cells which progresses to necrosis by 48 hr after injection. The pathogenesis of myonecrosis induced by these toxins can be better understood using electron microscopy to follow more closely the changes in the cells over time. Many toxins which cause local hemorrhage after injection into experimental animals have been isolated from snake venoms. The identification and isolation of hemorrhagic toxins from bacterial cultures is not as complete as the isolation of such toxins from snake venoms.
