Snake venoms poisoning with

All of these compounds fit our definition of drugs. It may seem strange to include poisons and snake venoms as drugs, but they too react with a biological system and produce a biological response—a bit extreme perhaps, but a response all the same. 

Naturally occurring poisons which are also more potent than the nerve gases are found in such sources as snake venoms, among the substances known as arrow poisons, and among toxic proteins found naturally, such as ricin, the toxic protein of the castor bean, and the bacterial toxins, such as tetanus toxin and botulinum toxin. Few of these highly toxic substances appear at present to be useful per se as chemical warfare agents, but intensive research on any of them may well lead the chemist to new toxic substances with military practicality. 

Medical personnel must remember, however, that with the advances of molecular genetics, it is possible to clone and produce many natural neurotoxins in relatively large quantities. For the present (1996), botulinum poisoning is a much more likely biological warfare agent than snake venom toxins. In future years, other (cloned) neurotoxins should be considered in the diagnosis. 

Crotoxin. Main component of the snake venoms of rattlesnakes (Crotalinae). It is a complex of a basic phospholipase A2 (C. B, Mr 13 500) with an acidic protein (C. A, Mr 10000) which transports the phospholipase to its site of action, the presynaptic membrane of the neuromuscular end-plates. Poisoning leads to local pain and necrosis. Systemic sequelae are tiredness, collapse, and shock through to death. In addition to the neurotoxicity, C. also has hemolytic action. 

Scorpion venoms secretions of the scorpion stinging apparatus. Active principles of S.v. are the neurotoxic scorpamines, which are similar to cobra toxins (see Snake venoms) with respect to M, (6,800-7,200, 4 disulfide bridges, 63-64 amino acid residues of known sequence), amino acid composition (high contents of basic and aromatic amino acids) and activity (both peripheral and central nervous system). The toxin from the North African scorpion, Androc-tonus australia, is one of the most potent known nerve poisons. 

The answer Is 4 /Diopter 11B2I. Toxin is the term used to identify poisons of naturai or biologic origin. Snake venoms, toxic mold metabolites, and poisonous principles in plants are examples of toxins. The term toxicant is synonymous with poison. 

Some naturally occurring extremely toxic and supertoxic chemicals are listed in Table 4.2, along with their environmental sources and toxicity targets. Some of these are toxins found in the venom of poisonous snakes or in the tissues of certain species of... 

The clinical features depend upon the type of snake bite. There are three main patterns neurotoxic, as with elapidae such as cobras and kraits vasculotoxic with alteration in blood coagulation as with vipers and myotoxic as with sea snakes although they are all often complicated by local tissue damage. The severity of poisoning will depend on the amount and potency of venom injected and the patient s general health. 

Use of Toxin Binding to Purify a Channel Protein a-Bungarotoxin is a powerful neurotoxin found in the venom of a poisonous snake (Bungarus multicinctus). It binds with high specificity to the nicotinic acetylcholine receptor (AChR) protein and prevents the ion channel from opening. This interaction was used to purify AChR from the electric organ of torpedo fish. 

Chemicals come in all shapes and sizes and derive from a variety of sources. While to many people the words chemical and indeed poison are synonymous with man-made things such as dioxin, organo-phosphates, pesticides, and nerve gas, there are many, many other chemicals that occur naturally These may be produced by plants, for example belladonna in deadly nightshade, and ricin in the castor bean, or bacteria, for example botulinum toxin. Various animals such as snakes and spiders produce toxic venoms, and some poisons occur naturally in the ground, like asbestos, cadmium, and lead. 

Plasma exchange is helpful in the removal of large molecular weight substances and highly protein-bound intoxicants. Toxic ingestions of poisonous mushrooms (e.g. amanita phaUoides [38, 39]) and snake-bite en-venomations [40] have been effectively treated with... 

Theriac became famous as a result of its association with the earliest extant work on poisonous animals, the Theriaca of Nicander of Colophon (second century bc). His poems describe venomous animals (snakes, scorpions, spiders, insects, and myriapods) and their bites as well as poisonous plants and prescribe specific remedies to counteract the effects of these poisons. Nicander s work was widely influential successive Greek and Roman authors took much of their information on toxicology from him he was read and cited for many centuries. 

A few extremely toxic and supertoxic chemicals are listed in Table 2, along with their environmental sources and toxicity targets. Some of these are toxins found in the venoms of poisonous snakes or in the tissues of certain species of animals. Dr. Findlay Russell, who has made enormous contributions to our understanding of the nature of animal toxins, their modes of biological action, and the procedures for treating people who have been envenomed or poisoned, estimates that there are about 1200 known species of poisonous or venomous marine animals, countless numbers of venomous arthropods (spiders), and about 375 species of dangerous snakes (out of a total of about 3500 species). 

Several of the most poisonous snakes in the world use inhibition of AChE as their means of killing. For example the Black Mamba (Dendroapsis polx/lepis) from Africa secretes fasciculins into its venom. The fasciculins are potent AChE inhibitors and make the Black Mamba s venom amongst the most potent venoms known only 21 mg (equivalent to about three grains of salt) would be needed to kill an average sized person. Indeed, a Hospital in South Africa reported treating seven patients for Mamba bites — all of whom died within 24 hours. The symptoms associated with a Mamba bite are tetany. 

It may be tempting to equate the concept of venom with poison, but to do so would be inaccurate. Many plants, for example, are poisonous but present no harm to humans because they have learned not to eat them. By contrast, one can be quite careful on a walk through the southwestern United States or Australian outback and still have an unfortunate accident involving the venom of a snake. In any given year, around 40,000 people die as a result of snakebites. To be more accurate with the definition of venom, therefore, it must be noted that venom is not just a poison, but one that is injected under the skin of the victim. 

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