Toxicology

From ArticleWorld

Toxicology is a field of research, science or medicine that deals with the study of those organic or inorganic molecules known to directly harm humans, animals or plants. Those who study it recognize that almost all toxicity is dose-related and that some bioactive chemicals are safe or even helpful when taken in a certain range but are dangerous at elevated levels of intake.

Focus

Toxicology is a broad field that overlaps with many other fields. Some toxicologists are also trained in ecology and study the pollutants that humans are exposed to in the air, food, soil and water. They study the origin of these pollutants and examine ways of reducing their production and of cleaning them up. They also study the effects of these pollutants, including human diseases like asthma or mercury poisoning. Sometimes they collaborate with the government to set regulations about industrial practices and the safe disposal of toxic pollutants.

Other toxicologists study issues such as drug toxicity in medicines that are helpful at smaller doses. They do research to develop criteria to measure what is known as the LD50 of a particular drug or medication. This is the dose of a toxin or medicine that will kill 50% of all humans who would theoretically ingest it. If a particular drug has an LD50 that is too close to its therapeutic range, it is often discarded as a therapeutic agent or is regulated very carefully due to its risks.

Toxicologists who study the toxicity of venoms or poisonous plants are called “toxinologists”. They determine which species are toxic to humans and how toxic each species is. They also study the mechanism of action of a type of biological toxin so that perhaps a medicinal antidote can be created to save the life of an exposed individual.

Toxins from bacteria and fungi are also studied by some toxicologists. Many bacteria are dangerous because they release toxins into the infected host. Toxicologists have discovered that the abrupt killing of some types of bacteria using antibiotics can actually kill the person because large amounts of toxins are released as the bacteria are killed all at once.

Some medical toxicologists study the effects of the liver on the toxicity of a particular agent. A chemical may not be toxic as its own chemical structure but only become toxic as the liver metabolizes the chemical into a bioactive toxic metabolite. This explains why some people are more affected by a toxin than others, with other things such as dose and body weight are taken into account. The liver acts differently among peoples exposed to the same chemical, resulting in differing amounts of toxic metabolites.

Medical considerations

Toxicologists studied the effects of botulism, the disease caused by the botulinum toxin in certain poorly-prepared foods. Eventually, research showed that, in small doses, this toxin could reduce facial wrinkles and decrease muscle spasticity. This is how the drug called Botox® was first developed and used for cosmetic purposes. When injected into spastic muscles, botulinum toxin can reduce the spasticity for several weeks.