Lecture 2: Etymology of ‘Toxicology’ Flashcards
Where is the word toxicology derived from? What does it mean?
Toxon (Gr) = a bow
Logos (Gr)= the study of
Toxikon (Gr)= a poisonous substance for arrows
Toxic is derived from toxikon in Greek
What is the older definition of toxicology?
The scientific study of poisons and their actions and detection, and treatment of the condition produced by them
What is the newer definition of toxicology?
is the study of the adverse effects of chemical, physical or biological agents on living organisms and ecosystems, including the prevention and amelioration of such adverse effects.
What is the simple(r) definition of toxicology?
Toxicology is the study of the harmful interactions between chemicals and biological systems.
- Anything can cause a harmful effect on an animal
- Anything is poisonous(toxic) at the right dose
- ex:We can die if we have to much water
What are the different areas of focus within toxicology?
Chemistry of toxicants.
• E.g., Molecular structures.
Biochemistry of how toxicants affect biological molecules.
• E.g., Impacts on enzyme function, binding to cellular receptors
Physiological effects on tissues, organs and whole organisms.
• E.g., Impacts on growth, development, reproduction, etc
Ecological effects of the toxicants in the environment.
• Environmental toxicology, ecotoxicology
Regulation of how we produce, store, transport and use chemicals
Why Study Toxicology?
- To understand risk, and what one needs to worry about.
~80,000 chemicals registered in the USA alone.
~2,000 new chemicals introduced each year.
-You never experience a single compound at a single time - You’re interested in protecting the environment.
- Environmental toxicology (fresh water)
- Ecotoxicology
Glass Beach, California- used to throw waste in the ocean and glass became pebbles(shows how badly we used to treat the enviroment) - It may help you land a job.
- You need a 200-level credit to graduate.
- You enjoy discussing horrible things that affect us and animals.
What does environmental toxicology look at?
Focuses on detecting compounds and impacts in the natural environment
• Largely focuses on the compound
ex- sewage wastewater from Calgary going into the bow river and Sask river and that system moves all the way through Sask and Manitoba ending up in Hudson Bay
Majority of dose of ibuprofen doesn’t get absorbed by the body and goes right thru us and goes to the sewage treatment plants which are designed to remove nutrients and not hormones or pharmaceuticals, and these go into the aquatic environment
Caffeine can be detected downstream of sewage plants anywhere in the world)
What is the difference between environmental and ecotoxicology?
Difference between Environmental and eco is environmental is looking at detecting compounds in the environment and eco is detecting responses in animals
What are 2 other important reasons as to why you should study toxicology? Give an ex
It’s really important for human health…
Mercury accumulates in the tissues of an animal and another animal comes and eats it they picked up the mercury- it accumulates as you move up the food chain
It’s really important for the environment…
Deepwater Horizon Oil Spill – 4 million barrels of oil spilled (~600 million liters) into gulf of mexico
Toxicant
a substance capable of producing a toxic effect when in contact with a living organism at a sufficiently high concentration
often use contaminant in the place of toxicant
-Substance that pollutes, spoils or poisons something.
-In the environment.
Toxin
a toxicant produced by a living organism (microbe, plant, or animal)
- i.e., a naturally produced toxicant.
- A poisonous animal must be touched by you.
- A venomous animal injects toxin into you.
Teratogen
substance capable of causing malformation during the development of the fetus.
• e.g., Thalidomide in the late 50’s early 60’s.
The company Richardson- Merrell, distributed thalidomide samples to physicians known as ‘clinical investigators’.
Thalidomide
was prescribed to pregnant women for morning sickness. It was found to be a teratogen that causes phocomelia (limbs close to the trunk or severely underdeveloped).
Who was Dr. Frances Kelsey?
a Canadian physician working for the USA Food and Drug Agency (FDA), prevented the licensing of thalidomide in the USA.
The Government of Canada at that time, authorized the marketing of thalidomide based on the same information that the American authorities found to be insufficient.
Mutagens
physical or chemical agents that change the genetic material, usually DNA, of an organism and thus increases the frequency of mutations above the natural background level. (toxicant that results in the changing of genetic material, alters geneteic sequence of DNA)
- UV and radioactive substances
Give an example of a mutagen
Benzopyrene (in green) is in tobacco smoke and can bind to DNA and form a DNA adduct(binds to the DNA and will cause it to, need to be repaired). When repaired by the cell, a different nucleotide base (mutation) can be accidently be inserted while trying to fix the DNA strand.
carcinogen
is any substance, radionuclide, or radiation that is an agent directly involved in causing cancer. (Compound that has been directly linked to the causing of cancer; some mutagens can lead to cancer but not all mutagens are carcinogens, carcinogens can lead to cancer that are not mutagens, mutually exclusive groups)
Carcinogen exposure increases the risk of developing cancer. The risk is higher for some carcinogens than others. For example, for benzopyrene, it is high… Note… mutagens aren’t necessarily carcinogens, and carcinogens aren’t necessarily mutagens!!!
How do different toxicants differ?
Differ in How They React to Water
Hydrophilic
(water loving): Dissolve in water, polar.
Hydrophobic
(water hating): Do not dissolve in water, non- polar. If ingested, will be stored in fat tissue so often called lipophilic
lipophilic
If ingested, will be stored in fat tissue
If something moves into fat tissue it has the potential to accumulate and then when eaten by other animals, it goes into them-bioaccumulation
Hydrophobic compounds have a bigger effect on animals and humans
Octane
- Non-polar (no partial charge)
- Cannot form hydrogen bonds
- Can form Van der Wall bonds
Water molecule
- Polar (partial charge across molecule)
- Can form hydrogen bonds
Octanol
- The hydroxyl (OH) end is polar
- The rest is not
- Thus, is amphiphatic
What are Xenobiotics? Give ex of some
substances foreign to life (“xeno” = foreign; “biotic” = relating to life)
- opposite of a toxin, a human made substance, produce them to help in our day to day lives and helped us a lot
Human-made substances that did not exist in nature before being synthesized in the laboratory
For example…
Agricultural pesticides
Industrial chemicals
Food additives
Flame retardants
etc.
List some common xenobiotics
Arenes (note: can be natural...) -polycyclic aromatic hydrocarbons (PAHs) Biphenyls -polychlorinated biphenyls (PCBs) Brominated fire retardants - polybrominated biphenyls (PBBs) Diphenyl ethers Polybrominated diphenyl ethers (PBDEs) Persistent Organic Pollutants (POP’s) Legacy Pollutants
