A Brief History of Toxicology
The historical development of toxicology began with early
cave dwellers who recognized poisonous plants and animals and used their
extracts for hunting or in warfare. By 1500 BC, written evidence indicated that
hemlock, opium, arrow poisons, and certain metals were used to poison enemies
or for state executions.
With time, poisons became widely used—and with great
sophistication. Notable poisoning victims include Socrates, Cleopatra, and
Claudius. By the time of the Renaissance and the Age of Enlightenment, certain
concepts fundamental to toxicology began to take shape. Noteworthy in this
regard were the studies of Paracelsus (~1500AD) and Orfila (~1800 AD).
Paracelsus determined that specific chemicals were actually
responsible for the toxicity of a plant or animal poison. He also documented
that the body's response to those chemicals depended on the dose received.
His studies revealed that small doses of a substance might be harmless or
beneficial whereas larger doses could be toxic. This is now known as the dose-response relationship, a major
concept of toxicology. Paracelsus is often quoted for his statement: "All
substances are poisons; there is none which is not a poison. The right dose
differentiates a poison and a remedy."
Orfila, a Spanish physician, is often referred to as the
founder of toxicology. It was Orfila who first established a systematic
correlation between the chemical and biological properties of poisons of the
time. He demonstrated effects of poisons on specific organs by analyzing autopsy
materials for poisons and their associated tissue damage.
The 20th century is marked by an advanced level of
understanding of toxicology. DNA (the molecule of life) and various biochemicals
that maintain body functions were discovered. Our level of knowledge of toxic
effects on organs and cells is now being revealed at the molecular level. It is
recognized that virtually all toxic effects are caused by changes in specific
cellular molecules and biochemicals.
WHAT IS TOXICOLOGY?
Toxicology deals with the study of adverse effects of
chemicals on living organisms, as well as in the study of symptoms, mechanisms,
treatment and detection of poisoning.
Its function is to identify poisons and search for treatments to include forensic toxicology. This involves the use of toxicological methods for legal purposes. The work of a forensic toxicologist falls into 3 categories: identifying of drugs such as cannabis, heroin and cocaine; detection of poisons and drugs in body fluids and organs; and to measure alcohol in urine or blood samples. The procedures and results must be interpreted and presented to the legal courts. The second function is the detection and testing of a fast growing numbers of new potentially toxic substances used in the workplaces like in cosmetics as food additives and as drugs and in agriculture examples are fertilizers, pesticides and insecticides. It overlaps with pharmacology , pathology and other fields.
Dose is the most important factors
that influence the toxic effect of specific chemicals. All chemicals, including
essential substances such as oxygen and water when administered in large doses
produce toxic effects. Other factor is the route of exposure. Living organisms
are exposed to chemicals via penetration to the skin, by inhalation and ingestion.
Inhalation is often the most serious route of exposure because substances are absorbed
into the body most efficiently through the lungs. The next factor is the fate
of chemicals after the organism is exposed. When chemical is absorbed, it may
travel throughout the body and can cause toxic effects to the remote sites
where adverse effect occurs and is also known as target organs. The last factor
is the time course of exposure. Toxicologist distinguish 2 classes of toxicity,
the acute toxicity this occurs shortly after a single exposure and chronic
toxicity occurs after a long term repeated exposure.
References:
Britannica Concise Encyclopedia
Bodziak, J., and Jon J. Nordby. Forensic
Science: An Introduction to Scientific and Investigative Techniques. CRC
Press, 2002.
Klaassen, C. D. Toxicology: The Basic
Science of Poisons. McGraw-Hill Companies, 2001.
Periodicals
Goldberger, B. A., and A. Polettini.
"Forensic Toxicology: Web Resources." Toxicology 173
(2002): 97–102.
Maurer H. H. "Liquid Chromatography-mass
Spectrometry in Forensic and Clinical Toxicology." J Chromatogr B
Biomed Sci Appl. 713 (1998): 3–25.
that's Toxicology.... thanks for reading!! :))
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