Some enzymatic activities of Egyptian snake venoms and a scorpion venom

Disseminated intravascular coagulation after cerastes vipera envenomation in a 3-year-old child: a case report

This study presents a case of severe disseminated intravascular coagulation (DIC) in a 3-year-old child following envenomation by the snake, Cerastes vipera. A literature search revealed very few similar cases. We describe a child who was bitten in his left foot by a snake identified as a C. vipera. Initial symptoms were relatively benign. Local signs included a hemorrhagic vesicle at the site of the bite with marked swelling of the entire leg. Twenty-four hours later, the child developed severe bleeding due to DIC, which lasted 5 days and required repeated administration of blood and blood products and total exchange transfusion. The patient was discharged from the hospital after 7 days in good condition. To the best of our knowledge, severe DIC following envenomation by a C. vipera has not been previously described in the literature. Treatment was essentially supportive. The case report indicates that a specific antivenin against this snake's venom should be made available in our area.

An in vitro and in vivo study of some biological and biochemical effects of Sistrurus Malarius Barbouri venom

Some possible biological and biochemical effects of Sistrurus Malarius Barbouri (SMB) crude venom were investigated. The acute median lethal doses of the venom under investigation were found to be 14.4 and 9.72 microg/g body weight (b.w.), respectively, in rats on i.p. administration. The possible neurotoxicity of acute, subchronic and chronic doses was investigated in-vivo and in-vitro. The venom at a dose level of 2 microg/g b.w. significantly impaired motor coordination, learning and retention, spontaneous activity and produced behavioural changes, muscle weakness and loss of righting reflex in mice. The same dose also produced a significant decrease in body temperature and inhibited acetylcholine-induced contraction of the isolated smooth (rabbit intestine) and skeletal (frog rectus abdominis) muscles and impaired transmission at the nerve muscle synapse of the rat phrenic nerve diaphragm preparation. The effects of the acute sublethal and chronic doses on carbohydrate metabolism revealed a hyperglycemic effect associated with a diminution of liver and muscle glycogen, while its effects on blood electrolytes (sodium and potassium) showed a significant elevation in the blood sodium level and a significant reduction in that of potassium. Serum enzymes were also affected. Levels of alkaline phosphatase (ALP), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities were moderately increased. The crude venom had an aggregatory effect on platelets and had also a phospholipase A2 activity while, on the other hand, it showed no L-amino acid oxidase activity. Testing of the effect of the venom on the plasma recalcification time showed that the venom had an anticoagulant effect in case of high dose (200 microg), while a coagulant effect was produced at a low dose of the venom (2.5 microg). SMB venom at a dose level of 1.94 microg/g b.w. (LD10) was found to exhibit no significant inhibitory effect on tumor growth when injected into mice.

Snake bite by Cerastes vipera in children: report of two cases

Two children, ages 2 and 4 years, envenomed by the snake Cerastes vipera are presented. Both children suffered from local pain and swelling of the hand that spread up to the shoulder in the 2-year-old and up to the elbow in the 4-year-old. A hemorrhagic blister was noted on the bitten finger in the younger patient. Urinary retention, tachycardia, and a slight prolongation of prothrombin time was noted in the 2-year-old, whereas hypertension and fever were observed in the 4-year-old. In both cases, the swelling receded gradually and the patients were discharged from the hospital after several days without any complications and in a good condition.

Envenoming by Cerastes viper - a report of two cases

Two cases of envenoming by Cerastes vipera are described Both were in snake collectors who were accidentally bitten on the finger while handling the snake. In both cases, local signs included a haemorrhagic bulla with fang marks, swelling and tenderness. These signs were mild in one case and moderately severe in the other, necessitating fasciotomy. No systemic signs were observed. Some coagulation abnormalities were found in both cases. In one, prolonged bleeding from the wound and a shortened euglobulin lysis time may suggest activation of the fibrinolytic mechanism. In the other, prolongation of prothrombin time occurred with no haemorrhagic diathesis. Treatment included fasciotomy in one case and elevation of the affected part and antibiotics in the other. It appears that the clinical course of this snakebite is relatively benign.

Snake venom action: are enzymes involved in it?

Enzymes were the first clearly recognized components of snake venoms. When several more were discovered, attempts were made to correlate venom action with enzymic functions. The last few years have seen most successful efforts in the identification, isolation and structrual elucidation of highly toxic polypeptides present in snake venoms, in particular of 'neurotoxins' and membrane-active toxins. Following this development the polypeptides were called the true toxic components and the enzymes lost their previous central position in venom pharmacology. The time, therefore, has come re-evaluate the role of enzymes in the complex interaction between snake and prey. While highly active polypeptides indeed dominate the actionof hydrophiid venoms, they appear to play a lesser role in crotalid venom action as compared with enzyme components. Enzymes are involved in many levels of venom action, e.g. by serving as spreading factors, of by producing very active agents, such as bradykinin and lysolecithins in tissues of preys or predators. Some toxins, e.g. the membrane-active polypeptides appear to participate in the interaction between membrane phospholipids and venom phospholipases. The classical neurotoxin, beta-bungarotoxin, has been recognized as a powerful phospholipase. Several instances are known which indicate that some enzymes potentiate the toxic action of others; the analysis of a single enzyme may, therefore, not fully reveal its biofunction. For 3 enzymes,ophidian L-amino acid oxicase, ATPpyrophosphatase, and acetylcholinesterase, some of the problems pertaining to venom toxicity are discussed.