Introduction

• Chem 451 is part of a three course group designed to provide an introduction to toxicology for students in chemistry and the natural resources and life sciences. Chem 451, Biochemical Toxicology, looks at what happens to toxins inside organisms, how toxins get into organisms and how they are eliminated. Chem 450, Chemical Concepts in Toxicant Behavior, looks at how toxins move through the environment, and how they are modified in the environment; finally, Chem 433, Chromatography, is a laboratory course focused on the most important techniques for the isolation and analysis of organic compounds.
• Chem 451 and Chem 450 are both seminar courses. In each the instructor lectures for the first 10 weeks or so to provide a basic background in the subject area. The last five weeks or so consists then of student presentations. For Biochemical Toxicology the seminars will focus on what happens to a toxin or toxin family inside organisms. It is not acceptable to report on toxins in the environment in this course, save that for Chem 450. Seminars should "bring us up-to-date." That is they should focus on a topic of current interest with a current literature. I expect to see references published within the past few months, as well as earlier literature as appropriate.
  • Because of our intimate class size this semester I have some extra time slots and what I am contemplating is discussing topics of current interest. With this in mind if you have nothing you see that excites you in terms of toxicology email me or suggest it in other ways and perhaps we'll give it a shot. Examples might include:
    • Local groups were very upset about the emissions from the pulp mill - are these emissions worrisome?
    • Dow-Corning lost a law suit and paid out billions of dollars for damage caused by silicon breast implants why is this now widely seen as a miscarriage of justice?
    • Should veterans who served in Viet Nam be compensated for injuries they credit to "agent orange"?
    • Is organic food less toxic?
  • Many other topics could be listed.
• Grading will be based on a midterm exam, a final exam and your seminar. The questions will be provided in advance for both exams. Past questions are currently posted on our web site as examples. You can assume that most of these questions will remain unchanged, but I may add questions or modify them slightly. The questions will become "finalized" at least one week before each exam. The exam will then consist of a selection from the questions (i.e. 3 or 4 for the midterm). I expect that you will have researched out and outlined the questions in advance. I recommend you attempt a "practice exam" to make sure you have sufficient time to write your essays (12-15 minutes each).

What is toxicology?

• It has been defined as "The science that defines the limits of safety of chemical agents." Thus we are concerned with the quantitative affects of chemicals. Note that all chemicals are toxic in extreme concentration. For example, we require oxygen within a range of concentration - too little and we suffocate, too much and we are poisoned. We also must be concerned with acute (brief and severe) versus chronic (long term) affects. For example, lead and mercury tend to be stored in the body, so low level concentrations in the environment will have no immediate effect, but long term can be extremely damaging.
• Toxicology is also referred to as the science of poisons. It is often considered as a subset of Pharmacology (the science of drugs), and is most often taught in the US in pharmacology departments. (Actually, we might consider Pharmacology a subset of Toxicology since all drugs are also poisons!)
• Toxicology is obviously of great interest in that it deals with the many hazardous substances in the environment, both natural and "un-natural." As such there is also a lot of public interest and politics involved with the study and dissemination of toxicological information.

Biochemical Toxicology focuses on the way in which chemicals and organisms interact, including

• Uptake: how do chemicals enter an organism;
• Distribution: where do chemicals go in the organism's body after uptake (for example non-polar organic molecules tend to deposit in fat and reside there for some time);
• Variations in response: there are frequently tremendous differences in the toxicity of a given compound in different species of organisms (dioxin is extremely toxic to female guinea pigs, much less so for many other organisms), and we also can see large variations of response between individuals of a single species;
• Kinetics: describes how the concentrations of a chemical change vs. time within an organism and thus when and for how long a given exposure may result in a toxic dose;
• Metabolism: describes how organisms modify chemicals. Generally toxins are detoxified and modified to increase their solubility and elimination, but this is not an intelligent system, so sometimes non-toxic substances become toxic!
• Types of responses: does a toxin inhibit an enzyme, cause genetic damage, bind to a receptor, alter a membranes integrity, cause cancer, etc.

Last modified 1 January 2010

© RA Paselk 2008