FACTOID # 21: 15% of Army recruits from South Dakota are Native American, which is roughly the same percentage for female Army recruits in the state.
 
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Encyclopedia > Toxicology

Toxicology (from the Greek words toxicos and logos [1]) is the study of the adverse effects of chemicals on living organisms [2]. It is the study of symptoms, mechanisms, treatments and detection of poisoning, especially the poisoning of people. The chief criterion regarding the toxicity of a chemical is the dose, i.e. the amount of exposure to the substance. Almost all substances are toxic under the right conditions. As Paracelsus, the father of modern toxicology said, “Sola dosis facit venenum” (only dose makes the poison). Paracelsus, who lived in the 16th century, was the first person to explain the dose-response relationship of toxic substances. A chemical substance is any material substance used in or obtained by a process in chemistry: A chemical compound is a substance consisting of two or more chemical elements that are chemically combined in fixed proportions. ... The skull and crossbones symbol traditionally used to label a poisonous substance. ... Paracelsus Paracelsus (born 11 November or 17 December 1493 in Einsiedeln, Switzerland - 24 September 1541) was an alchemist, physician, astrologer, and general occultist. ... (15th century - 16th century - 17th century - more centuries) As a means of recording the passage of time, the 16th century was that century which lasted from 1501 to 1600. ... The Dose-response relationship describes the change in effect on an organism caused by differing levels of exposure (or doses) to a substance. ...


Many substances regarded as poisons are toxic only indirectly. An example is "wood alcohol," or methanol, is chemically converted to formaldehyde and formic acid in the liver. It is the formaldehyde and formic acid that cause the toxic effects of methanol exposure. Many drug molecules are made toxic in the liver, a good example being acetaminophen (paracetamol), especially in the presence of alcohol. The genetic variability of certain liver enzymes makes the toxicity of many compounds differ between one individual and the next. Because demands placed on one liver enzyme can induce activity in another, many molecules become toxic only in combination with others. A family of activities that engages many toxicologists includes identifying which liver enzymes convert a molecule into a poison, what are the toxic products of the conversion and under what conditions and in which individuals this conversion takes place. Methanol, also known as methyl alcohol or wood alcohol, is a chemical compound with chemical formula CH3OH. It is the simplest alcohol, and is a light, volatile, colourless, flammable, poisonous liquid with a distinctive odor that is somewhat sweeter than ethanol (ethyl alcohol). ... The chemical compound formaldehyde (also known as methanal), is a gas with a strong pungent smell. ... Formic acid (systematically called methanoic acid) is the simplest carboxylic acid. ... Liver of a sheep: (1) right lobe, (2) left lobe, (3) caudate lobe, (4) quadrate lobe, (5) hepatic artery and portal vein, (6) hepatic lymph nodes, (7) gall bladder. ... Oral medication A medication is a licenced drug taken to cure or reduce symptoms of an illness or medical condition. ... Acetaminophen (USAN) or paracetamol (INN), is a popular analgesic and antipyretic drug that is used for the relief of fever, headaches, and other minor aches and pains. ... Functional group of an alcohol molecule. ... Ribbon diagram of the enzyme TIM, surrounded by the space-filling model of the protein. ...


The term LD50 refers to the dose of a toxic substance that kills 50 percent of a test population (typically rats or other surrogates when the test concerns human toxicity). LD50 estimations in animals became obsolete in 1991 and are no longer required for regulatory submissions as a part of pre-clinical development package.[citation needed] An LD50 test being administered In toxicology, the LD50 or colloquially semilethal dose of a particular substance is a measure of how much constitutes a lethal dose. ... Species 50 species; see text *Several subfamilies of Muroids include animals called rats. ... An LD50 test being administered In toxicology, the LD50 or colloquially semilethal dose of a particular substance is a measure of how much constitutes a lethal dose. ... 1991 (MCMXCI) was a common year starting on Tuesday of the Gregorian calendar. ... Activities that need to be performed and results to be obtained a before a clinical trial in humans can begin. ...


Mathieu Orfila is considered to be the modern father of toxicology, having given the subject its first formal treatment in 1813 in his Trait des poisons, also called Toxicologie generate. Mathieu Joseph Bonaventure Orfila. ... 1813 is a common year starting on Friday (link will take you to calendar). ...


However, Theostratus Phillipus Auroleus Bombastus von Hohenheim (1493 - 1541) (also referred to as Paracelsus, from his belief that he was above or beyond the work of Celsus - the Roman physician from the first century) is widely regarded as "the father" of modern toxicology. He is credited with the classic toxicology soundbite "All things are poison and nothing is without poison; only the dose makes a thing a poison." The original German reads: "Alle Dinge sind Gift und nichts ist ohne Gift; allein die Dosis machts, dass ein Ding kein Gift ist." This is often condensed to "The dose makes the poison". Paracelsus Paracelsus (born 11 November or 17 December 1493 in Einsiedeln, Switzerland - 24 September 1541) was an alchemist, physician, astrologer, and general occultist. ... To meet Wikipedias quality standards, this article or section may require cleanup. ...


See also

To meet Wikipedias quality standards, this article or section may require cleanup. ... In vitro toxicology is the scientific analysis of the effects of toxic chemicals on cultured bacteria or mammalian cells. ... Water pollution Pollution is the release of environmental contaminants. ... The skull and crossbones is a common symbol for toxicity. ... An enzyme inhibitor is a molecule that binds to an enzyme and decreases its rate of reaction. ...

References

  • Amdur MO, Doull J, Klaassen, CD. 1993. Cassarett and Doull's Toxicology: The Basic Science of Poisons. New York: McGraw-Hill, Inc.
  • Schrager, Thomas F. "What is Toxicology", http://www.toxicologysource.com, October 4, 2006.
  • Gilbert, Steven G. A Small Dose of Toxicology – The Health Effects of Common Chemicals. CRC Press, Boca Raton, February 2004, p 266. – see web site http://www.asmalldoseof.org/

1993 (MCMXCIII) was a common year starting on Friday of the Gregorian calendar and marked the Beginning of the International Decade to Combat Racism and Racial Discrimination (1993-2003). ... 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ...

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