Toxins and Antidotes

I. Toxin,

A. Poisonous substance produced by the metabolic activities of certain living organisms, including bacteria, insects, plants, and reptiles.

B. Some bacteria secrete toxins in tissues that they colonize; these are true toxins.

1. Other bacteria retain most of the poisonous material within themselves.

2. The toxins are liberated only when the bacteria become disintegrated by chemical, physical, or mechanical means.

C. Phytotoxins - the characteristic poisons and venoms produced by various plants

D. Zootoxins - those produced by animals.

E. The more important true toxins causing infection in humans are those of botulism, dysentery, tetanus, and diphtheria.

F. Because of their extreme susceptibility to various chemical and physical influences, such as light, heat, and age, toxins are difficult to isolate, and knowledge of toxins has been gained through the lesions and symptoms that they produce when injected into animals.

G. Although all toxins are poisonous, in order to become effective they must chemically combine with the animal cells.

H. With the exception of botulin, they are destroyed by the gastrointestinal juices.

I. Although the exact chemical nature of toxins is unknown, they are generally thought to be toxalbumins, substances closely allied to proteins.

J. It has also been abundantly demonstrated that toxins are colloid in nature and bear a close resemblance to enzymes.

K. Toxins are absolutely specific synthetic products, unlike ptomaines, which are cleavage products from the medium on which the bacteria grow.

L. In certain forms, toxins can give rise to antibodies, natural defensive substances produced in the body.

M. Toxoids are toxins that are treated to destroy their toxicity but that remain potent enough to create antibodies when injected into the body.

II. Antidote,

A. Drug or other remedy that counteracts the effects of a poison.

B. It may neutralize the poison chemically, as bicarbonate taken as an antidote for acid; it may render the poison insoluble and therefore harmless, as Epsom salt as an antidote for lead; it may absorb the poison, as charcoal as an antidote for alkaloids; or it may coat the stomach, as olive oil as an antidote for ammonia poisoning.

III. Pesticides

A. Broadly defined, a pesticide is any agent used to kill or control any pest (1, 2).

B. Pests can be insects, rodents or birds, unwanted plants (weeds), fungi, or microorganisms such as bacteria and viruses.

C. Though often misunderstood to refer only to insecticides, the term pesticide also applies to herbicides, fungicides, and various other substances used to control pests.

D. Under United States law, a pesticide is also any substance or mixture of substances intended for use as a insect or plant growth regulator, insect mating disruptor or egg sterilant, defoliant, or desiccant.

E. Many household products are pesticides, such as cockroach sprays and baits, rat poisons, pet flea collars, products that kill mold and mildew, and kitchen disinfectants.

F. 1,3-Indandione - Rodenticides that act as anticoagulants. High acute toxicity. Indandione structure, with substituents. Representative chemical structure here.

G. 2,6-Dinitroaniline - Herbicidal compounds containing a dinitroaniline functional group. While these compounds are not acutely toxic to animals, many of them are possible human carcinogens.

H. Acetanilide - Herbicidal compounds with an acetanilide functional group. These compounds are frequently found with their breakdown products as contaminants in groundwater. Examples are alachlor and metolachlor.

I. Alkyl phthalate - Compounds derived from phthalic acid. Used as insecticides and insect repellents, as well as softeners in plastics manufacturing. Some of these compounds are suspected endocrine disruptors.

J. Azole - Fungicidal compounds, a few of which are carcinogenic.

K. Benzimidazole - Fungicidal compounds with a benzimidazole moiety. Benomyl and thiabendazole are examples.

L. Carboxamide - Fungicidal compounds. Carboxin and flutolanil are examples.

M. To eliminate pesticide exposure:

1. Wash your hands before you prepare or eat foods. Neglecting this habit is one of the greatest threats to food safety.

2. Avoid raw eggs, raw oysters or raw fish.

3. Wash all produce thoroughly with cold water.

4. Eat a low-fat diet and maintain a healthy weight. Toxins are often stored in the body's fat cells.

5. Eat a variety of foods in moderation.

6. Cook meats and poultry thoroughly. Assume they are contaminated with bacteria. Wash hands and cutting surfaces and utensils with hot, soapy water immediately after preparation.

7. If you wish to buy organically grown foods, look for certification by Organic Growers Associations.

References

Pesticide Action Network. http://www.panna.org/panna/. 2001. Pesticide Action Network North America (PANNA).

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