Toxicology – An overview
An introduction to the science of poisons, with its history, concepts and study methods.
TOXICOLOGY
Toxicology, often referred to as “the science of poisons”, is the study of adverse effects of chemical or physical agents on living organisms. The toxins may affect various levels within the body, from cells to organs, or even a specific biochemical.
History of toxicology
This post introduces the definition of toxicology as well as explains the fundamental concepts involved in this field of science, including dose-response relationship, exposure assessment and risk characterization. The research also highlights some methods of studying toxicology and their respective functions.
Paracelsus (1493-1541)
Orfila (1787-1853)
Toxicology is a multidisciplinary field of science, combining knowledge of pharmacology, medicine and environmental science to provide informations of how metabolic reactions and organ functions of an organism are altered by the presence of an agent to treat intoxication and poisoning, which helps us to develop methods to limit the exposure of harmful substances and working on safer products including consumer goods or drugs.
One of the earliest origins of toxicology began with early cave inhabitants who acknowledged some poisonous plants and animals, and they extracted the poison to use in hunting or in welfare. By 1500 BC, written evidence illustrated that hemlock, opium, arrow poisons and some metals were utilized for state executions as well as to get rid of the enemies. Eventually, the usage of poisons became omnipresent and highly sophisticated, with some notable victims including Socrates, Cleopatra, and Claudius. By the time of the Renaissance and Age of Enlightenment, some fundamental concepts related to toxicology started to form with the
Studies of Paracelsus (~1500 AD) and Orfila (~1800 AD) being some of the most prominent.
Paracelsus’ study
His research on plant and animal poisons determined that specific chemicals were the factors responsible for the toxicity. He also documented that the dosage consumed plays a significant role in the reaction of a body to the chemicals. The studies later revealed that one substance might be beneficial in small amounts whereas it could be toxic in larger doses. This is the concrete evidence for the formation of a major concept in toxicology: the dose-response relationship. For Paracelsus’ breakthrough, he was referred to as one of the founders of modern toxicology. The results of the research supported his most famous quote, stating that “All substances are poisons”; it is the dose that causes the adverse effects.
Orfila’s study
Orfila was a Spanish physician but people commonly know him as the founder of toxicology, since he came up with the first systematic correlation between chemical and biological properties of poisons at that time. By analyzing autopsy materials for poisons and their associated tissue damage, he indicated the effects of them on specific organs. His findings marked the elemental theory of toxicology which stated that virtually all toxic effects resulted from changes in specific cellular molecules and biochemicals.
Core concepts and principles:
Dose-response relationship: This fundamental concept investigates the correlation between the severity of the adverse effects and the dose consumed. Converting the results of the study to a dose-response curve, scientists illustrate that as the dose increases, magnitude of the detrimental effects generally goes up until it reaches a certain threshold, beyond which additional amounts may lead to more negative outcomes.
Exposure assessment: This involves evaluating the frequency, duration, and intensity of exposure to determine the potential risk of a chemical.
Risk characterization: This process merges information on toxicity and exposure to predict the likelihood of detrimental effects, so risk characterization is often used to advise regulatory decisions and safety guidelines.
Methods of Toxicological Assessment
In Vitro studies: the investigation is carried out outside of a living organism, typically in a controlled laboratory environment with the use of cells or living tissues, providing initial perceptions of the mechanism of affecting a substance to a biological system.
In Vivo studies: The investigation entails live animals testing to observe the effects of different chemicals in an internal organism context. Despite the predominance of ethical considerations, such studies are vital for understanding complex interactions within living systems.
Epidemiological Studies: Data collected from a human population is analyzed to identify the association between exposure to toxic agents and health impacts, providing a thorough understanding of the effects of toxicants on public health in the real world.
Resources:
“Introduction to toxicology – Children’s health and Environment” (CHEST Training Package for the Health Sector)
https://ec.europa.eu/health/ph_projects/2003/action3/docs/2003_3_09_a21_en.pdf
“Toxicology” (National Institute of Environmental Health Science)
“Toxicology” (Wikipedia)
https://en.wikipedia.org/wiki/Toxicology
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