Toxicology (from the Greek words τοξικός - toxicos "poisonous" and logos) is a branch of biology, chemistry, and medicine concerned with the study of the adverse effects of chemicals on living organisms.^[1] It is the study of symptoms, mechanisms, treatments and detection of poisoning, especially the poisoning of people.

Lithograph of Mathieu Orfila

Dioscorides, a Greek physician in the court of the Roman emperor Nero, made the first attempt to classify plants according to their toxic and therapeutic effect.^[2] Ibn Wahshiya wrote the Book on Poisons in the 9th or 10th century.^[3]

Mathieu Orfila is considered to be the modern father of toxicology, having given the subject its first formal treatment in 1813 in his Traité des poisons, also called Toxicologie générale.^[4]

In 1850 Jean Stas gave the evidence that the Belgian Count Hypolyte Visart de Bocarmé killed his brother-in-law by poisoning with nicotine^[5]

Theophrastus Phillipus Auroleus Bombastus von Hohenheim (1493–1541) (also referred to as Paracelsus, from his belief that his studies were above or beyond the work of Celsus - a Roman physician from the first century) is also considered "the father" of toxicology.^[6] He is credited with the classic toxicology maxim, "Alle Dinge sind Gift und nichts ist ohne Gift; allein die Dosis macht, dass ein Ding kein Gift ist." which translates as, "All things are poison and nothing is without poison; only the dose makes a thing not a poison." This is often condensed to: "The dose makes the poison" or in Latin "Sola dosis facit venenum".

The relationship between dose and its effects on the exposed organism is of high significance in toxicology. The chief criterion regarding the toxicity of a chemical is the dose, i.e. the amount of exposure to the substance. All substances are toxic under the right conditions. 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 are no longer required for regulatory submissions as a part of pre-clinical development package.^{[citation needed]}

The conventional relationship (more exposure equals higher risk) has been challenged in the study of endocrine disruptors. Toxicity is species-specific, lending cross-species analysis problematic. Newer methods are available to bypass animal-testing. ^[7]

Toxicologist Duties[link]

In order to research and assess the effects of chemicals, toxicologists perform carefully designed studies and experiments. These experiments help identify the specific amount of a chemical that may cause harm and potential risks of being near or using products that contain certain chemicals. Research projects may range from assessing the effects of toxic pollutants on the environment to evaluating how the human immune system responds to chemical compounds within pharmaceutical drugs.

While the basic duties of toxicologists are to determine the effects of chemicals on organisms and their surroundings, specific job duties may vary based on industry and employment. For example, forensic toxicologists may look for toxic substances in a crime scene, whereas aquatic toxicologists may analyze the toxicity level of wastewater.

Toxicology Starting Pay[link]

The U.S. Bureau of Labor Statistics (BLS) notes that jobs for biological scientists, which generally include toxicologists, were expected to increase by 21% between 2008 and 2018 (www.bls.gov). The BLS notes that this increase could be due to research and development growth in biotechnology, as well as budget increases for basic and medical research in biological science. Salary.com notes that the median annual salary for toxicologists as of February 2011 was $84,000, while the middle 50% earned between $84,000 and $90,000.

Requirements for a Toxicologist[link]

Bachelor's degree programs in toxicology cover the chemical makeup of toxins and their effects on biochemistry, physiology and ecology. After introductory life science courses are complete, students typically enroll in labs and apply toxicology principles to research and other studies. Advanced students delve into specific sectors, like the pharmaceutical industry or law enforcement, which apply methods of toxicology in their work.

The Society of Toxicology (SOT) recommends that undergraduates in postsecondary schools that don't offer a bachelor's degree in toxicology consider attaining a degree in biology or chemistry (www.toxicology.org). Additionally, the SOT advises aspiring toxicologists to take statistics and mathematics courses, as well as gain laboratory experience through lab courses, student research projects and internships.

See also[link]

References[link]

External links[link]

Look up toxicology in Wiktionary, the free dictionary.

• Toxicology at the Open Directory Project
• National Library of Medicine's "Toxicology Tutor" provides basic information on the science of toxicology.

This article includes a list of references, but its sources remain unclear because it has insufficient inline citations. Please help to improve this article by introducing more precise citations. (April 2011)

Bruce Ames
Bruce Ames
Born	(1928-12-16) 16 December 1928 (age 83) New York City
Nationality	United States
Fields	Molecular Biology, Biochemistry
Institutions	University of California, Berkeley Children's Hospital Oakland Research Institute
Alma mater	California Institute of Technology, Cornell

Bruce Nathan Ames (born December 16, 1928) is an American biochemist. He is a professor of Biochemistry and Molecular Biology at the University of California, Berkeley, and a senior scientist at Children's Hospital Oakland Research Institute (CHORI). He is the inventor of the Ames test, a system for easily and cheaply testing the mutagenicity of compounds.

Biography[link]

Dr Ames was born and raised in New York City. He is a graduate of the Bronx High School of Science. His undergraduate studies were at Cornell University in Ithaca, New York, and his graduate studies were completed at the California Institute of Technology.^[1]

Ames was elected a Fellow of the American Academy of Arts and Sciences in 1970.^[2]

He is a recipient of the Bolton S. Corson Medal in 1980, Tyler Prize for Environmental Achievement in 1985, the Japan Prize in 1997, the National Medal of Science in 1998 and the Thomas Hunt Morgan Medal in 2004,^[3] among many others.

His research focuses on cancer and aging and he has authored over 500 scientific publications. He is among the few hundred most-cited scientists in all fields.

Ames' current research includes identifying agents that delay the mitochondrial decay of aging, understanding the role of mitochondrial decay in aging, particularly in the brain, optimizing micronutrient intakes in the population to prevent disease, malnutrition, and obesity. He is also interested in mutagens as they relate to cancer prevention and aging.

Ames on synthetic carcinogens[link]

Bruce Ames developed the Ames test, described in series of papers in the 1970s, which is a cheap and convenient assay for mutagens and therefore potential carcinogens. The Ames test uses the bacteria Salmonella typhimurium to test for mutagens. Previous carcinogenic testing used live animals, and are therefore expensive and time-consuming. This made animal testing impractical for use in screening on a wide scale, and reduced the number of compounds that could be tested. The Ames test is widely used as an initial screen for possible carcinogens and has been used to identify potential carcinogens previously used in commercial products,^[4] and their identification led to some of those formulations, such as chemicals used in hair dye,^[5] being withdrawn from commercial use. The ease with which Ames test allows widely-used chemicals to be identified as possible carcinogens made him an early hero of environmentalism.^[6]

Subsequent work in Ames' lab involved looking at an overview of what was mutagenic or carcinogenic, and to what degree. Previously, scientists tended to only look for positive or negative results without considering the magnitude of the effect, which meant that as more and more items were shown to be potentially mutagenic, there was no system for evaluating the relative dangers. He also continued to test various natural and man-made compounds, and discovered that, despite what he and others had assumed, naturally occurring compounds were not turning out to be benign as compared to man-made ones. His continued work eventually led to his falling out of favor with many environmentalists. As natural chemicals turned out to also be frequently mutagenic, he argued that environmental exposure to manufactured chemicals may be of limited relevance to human cancer, even when such chemicals are mutagenic in an Ames test and carcinogenic in rodent assays.^[7] He contended that most human genetic damage arises from the oxidation of DNA during normal metabolism, and that the most important environmental carcinogens may include some whose chief effect is to cause the chronic division of stem cells whereby the normal protective mechanisms of a cell become less effective.

He argued against the banning of synthetic pesticides and other chemicals such as Alar which have been shown to be carcinogenic.^[6] He was concerned that overzealous attention to the relatively minor health effects of trace quantities of carcinogens may divert scarce financial resources away from major health risks, and cause public confusion about the relative importance of different hazards. Ames considered himself a leading “contrarian in the hysteria over tiny traces of chemicals that may or may not cause cancer", and said that "if you have thousands of hypothetical risks that you are supposed to pay attention to, that completely drives out the major risks you should be aware of."^[8]

References[link]

External links[link]

• Bruce Ames official website. Scientific papers, lectures and other media available here.
• CHORI biography and information
• University of California biography
• Interview with Ames in Reason
• Radio interview with Ames on KQED Forum hosted by Michael Krazny
• Juvenon Cellular Health: Company created by Bruce Ames and UC Berkeley Scientists
• Bruce Ames video interview in short Juvenon documentary