Toxin

toxin

 [tok´sin]

a poison, especially a protein or conjugated protein produced by certain animals, higher plants, and pathogenic bacteria. Bacterial toxins characteristically do not cause symptoms until after a period of incubation while the microbes multiply, or (as happens with botulism) the preformed toxin reaches and affects the tissue. Usually only a few toxin-producing agents are introduced into the body, and it is not until there are enough of them to overwhelm the leukocytes and other types of antibodies that symptoms occur. In some cases of food poisoning, symptoms are almost immediate because the toxin is taken directly with the food. Toxins can cause antitoxins to form in the body, thus providing a means for establishing immunity to certain diseases.

bacterial t's toxins produced by bacteria, including exotoxins, endotoxins, enterotoxins, neurotoxins, and toxic enzymes. See also toxin.

botulinal toxin (botulinum toxin) (botulinus toxin) one of seven type-specific, immunologically differentiable exotoxins (types A to G) produced by Clostridium botulinum,neurotoxins usually found in imperfectly canned or preserved foods. They cause botulism by preventing release of acetylcholine by the cholinergic fibers. Type A is one of the most powerful poisons known; it is also used therapeutically by injection to inhibit muscular spasm in the treatment of dystonic disorders such as blepharospasm and strabismus, to treat wrinkles of the upper face, and to reduce anal sphincter pressure to promote healing of chronic anal fissure. Type B is injected in treatment of cervical dystonia. Called also botulin.

cholera toxin an exotoxin produced by Vibrio cholerae; a protein enterotoxin that binds to the membrane of enteric cells and stimulates the adenylate cyclase system, causing the hypersecretion of chloride and bicarbonate ions, resulting in increased fluid secretion and the severe diarrhea characteristic of cholera.

clostridial toxin one elaborated by species of Clostridium, including those causing botulism (botulinus toxin), gas gangrene (gas gangrene toxin), and tetanus (tetanus toxin). In addition, C. difficile produces an exotoxin causing severe intestinal necrosis and C. perfringens produces exotoxins causing gas gangrene, intestinal necrosis, hemolysis, cardiotoxicity, and deoxyribonuclease and hyaluronidase activity, as well as an enterotoxin causing food poisoning.

Dick toxin erythrogenic toxin.

diphtheria toxin a protein exotoxin produced by Corynebacterium diphtheriae that is primarily responsible for the pathogenesis of diphtheria and related infections; it is an enzyme that activates transferase II of the mammalian protein synthesizing system.

diphtheria toxin for Schick test a sterile solution of the diluted, standardized toxic products of Corynebacterium diphtheriae; used as a dermal reactivity indicator in the schick test of immunity to diphtheria.

dysentery toxin any of various exotoxins produced by species of Shigella; the one formed by S. dysenteriae serotype 1 is a potent neurotoxin with hemorrhagic and paralytic properties.

erythrogenic toxin a bacterial toxin from certain strains of Streptococcus pyogenes that produces an erythematous reaction when injected intradermally and is responsible for the rash in scarlet fever.

extracellular toxin exotoxin.

gas gangrene toxin an exotoxin that causes gas gangrene; there are at least 10 types produced by Clostridium perfringens and others produced by C. noriyi and C. septicum.

streptococcal toxin a mixture of exotoxins formed by Streptococcus pyogenes.

tetanus toxin the potent exotoxin produced by Clostridium tetani, consisting of two components, one a neurotoxin (tetanospasmin) and the other a hemolysin (tetanolysin).

Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

tox·in

(tok'sin),

A noxious or poisonous substance that is formed or elaborated either as an integral part of the cell or tissue (endotoxin), as an extracellular product (exotoxin), or as a combination of the two, during the metabolism and growth of certain microorganisms and some higher plant and animal species.

[G. toxikon, poison]

Farlex Partner Medical Dictionary © Farlex 2012

toxin

(tŏk′sĭn)

n.

1. A poisonous substance, especially a protein, that is produced by living cells or organisms and is capable of causing disease when introduced into the body tissues but is often also capable of inducing neutralizing antibodies or antitoxins.

2. A poisonous or harmful nonbiological substance, such as a pollutant.

The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.

toxin

A poison or noxious thing produced by animals, plants, or bacteria. See Amatoxin, Anaphylatoxin, Bacterial toxin, Batrachotoxin, Biotoxin, Botulinum toxin, Bungarotoxin, Coley's toxin, Endotoxin, Exotoxin, Heat-stable toxin, Immunotoxin, Lethal toxin, Middle molecule toxin, Neurotoxin, Phallotoxin, Picrotoxin, Recombinant toxin, Rhizotoxin, Shiga neurotoxin, Tetanospasmin.

McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.

tox·in

(tok'sin)

1. A noxious or poisonous substance that is formed or elaborated as an integral part of the cell or tissue, as an extracellular product (exotoxin), or as a combination of the two during the metabolism and growth of certain microorganisms and some higher plant and animal species.

2. A common misnomer for poison.

[G. toxikon, poison]

Medical Dictionary for the Health Professions and Nursing © Farlex 2012

toxin

Any substance produced by a living organism that is poisonous to other organisms. Bacterial disease is largely the result of poisoning by the toxins they produce. Some bacteria release soluble exotoxins that act remotely. Others produce only endotoxins which operate only locally. Some bacterial toxins are among the most poisonous substances known.

Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005

toxin

a nonenzymic metabolite of one organism which is injurious to another organism. see TETANUS, BOTULISM.

Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005

Toxin

A poison. In the case of scarlet fever, the toxin is secreted as a byproduct of the growth of the streptococcus bacteria and causes a rash.

Mentioned in: Botulism, Cholera, Enterobacterial Infections, Fasting, Fish and Shellfish Poisoning, Sore Throat, Stool Culture, Tetanus, Toxic Shock Syndrome

Gale Encyclopedia of Medicine. Copyright 2008 The Gale Group, Inc. All rights reserved.

tox·in

(tok'sin)

Noxious or poisonous substance formed or elaborated either as an integral part of the cell or tissue (endotoxin), as an extracellular product (exotoxin), or as a combination, during metabolism and growth of some microorganisms and some higher plant and animal species.

[G. toxikon, poison]

Medical Dictionary for the Dental Professions © Farlex 2012