Introduction and Principles of Toxicology Flashcards
What is toxicology?
study of adverse effects of xenobiotics on living systems
toxicon = poison
logos = scientific study
STUDY OF POISONS
What is the difference between toxins and toxicants?
TOXIN = poison produced by living organisms (botulinum neurotoxin)
TOXICANT = man-made poisonous substance (organophosphates)
What are xenobiotics?
any substances foreign to an organism, or any compound no found within the normal metabolic pathways of a biologic system
What is the universal symbol of poisonous substances?
skull and crossbones
Toxicology is multidisciplinary. What 4 fields greatly contribute?
- chemistry
- physiology
- biochemistry
- pathology
What is mechanistic toxicology? Descriptive toxicology? Regulatory toxicology?
MECHANISTIC: study of cellular, biochemical, and molecular mechanisms of action
DESCRIPTIVE: toxicity testing for safety and regulatory purposes
REGULATORY: assessment of chemical risk from available data
What is forensic toxicology? Clinical toxicology? Environmental toxicology?
FORENSIC: medical-legal aspects of poisoning (CSI)
CLINICAL: diagnosis and treatment of toxicoses
ENVIRONMENTAL: effects of chemicals and pollutants in the environment on nonhuman subjects
Why is toxicology considered as old as humanity? Who where the early toxicologists?
early humans knew what to eat without harm and were able to recognize poisonous plants and animals and used their extracts for hunting and warfare
herbalists, witches, philosophers, alchemists
What is the oldest documentation of medicine?
Ebers Papyrus from 1500 BC, which contains >800 magical formulae and remedies with information on toxic plants and metals
Who is considered the father of toxicology? Why?
Paracelsus
advocated focus on “toxicon” and pioneered the dose-response relationship
all things are poisonous, it is only the dose that makes a thing not a poison
What 3 concepts were advanced by Paracelsus?
- need for experimentation in examining response to chemicals
- need to distinguish between therapeutic and toxic properties of chemicals based on dose
- specificity of therapeutic and toxic effects of chemicals
Who was Orfila? What did he discover?
pioneered quantitative toxicology to relate chemical content and toxicity and introduced experimental and forensic toxicology
used autopsy material and chemical analysis for legal proof of arsenic poisoning - Marsh Test (cause and effect)
What did Francois Magendie do?
pioneered mechanistic toxicology to determine the mechanisms of action of strychnine, emetine, and arrow poisons
What was the 1960s considered with regard to toxicology? What important agency was discovered?
era of public awareness - birth defects, pesticides wiping out bird populations (Rachel Carson and Silent Spring)
launch of the Environmental Movement lead to the development of the US Environmental Protection Agency
How has toxicology developed from the pre-20th century to the mid-20th century? Today?
PRE-20TH CENTURY - observational; mostly focused on domestic animals used for food, fiber, transportation, and power (plant toxicoses and their antidotes)
MID-20TH CENTURY - experimental; increased population of companion animals, large-scale food animal production, and reduced use of animal power
TODAY - mechanistic; comparative approach driven by concerns for human health
What makes something poisonous?
the dose
all substances are poisons, the dose differentiates a poison from remedy