1.1 Toxicology Principles

Question 1

Define toxicology:

Answer 1

Studying how adverse effects cause damage to organisms and the environment for prevention

Question 2

Define toxicological research:

Answer 2

Identifying the cellular and molecular mechanisms of action of toxic chemicals to see the extent of their effect on organ systems

Question 3

Define xenobiotic:

Answer 3

Any foreign compound that’s not naturally in an organism

Question 4

Define poison:

Answer 4

Damage causer

Question 5

Define toxin:

Answer 5

Naturally-occuring damage causer

Question 6

Define toxicant:

Answer 6

Man-made damage causer

Question 7

Define venom:

Answer 7

Naturally-occuring damage causer delivered via apparatus

Question 8

What is up-and-down toxicity testing?

Answer 8

Give dose to one animal, let it sit for a week, and then increase or decrease the dose in the next animal
- Find the approximate lethal dose (ALD)
- Less animals than LD50 study (6 vs 45)

Question 9

What is approximate lethal dose (ALD)?

Answer 9

The lowest dose that death occurs, measured in up-and-down toxicity studies

Question 10

What is toxication?

Answer 10

The metabolism of a drug to produce a toxic metabolite

Question 11

What is detoxication?

Answer 11

A metabolic process by which a substance’s toxicity is reduced

Question 12

What are ROS/RNS?

Answer 12

Reactive oxygen/nitrogen species

Question 13

Define ED50:

Answer 13

The median effective dose, the dose that produces a therapeutic effect in 50% of the population

Question 14

Define TD01:

Answer 14

The dose that is toxic to 1% of the population

Question 15

Define ED99:

Answer 15

The dose that produces a therapeutic effect in 99% of the population

Question 16

Define MTD:

Answer 16

Maximum tolerable dose, the largest dose that prevents weight gain over 90 days

Question 17

What is a graded response?

Answer 17

A dose-dependent response ex. heart rate, blood pressure (how much, #’s)

Question 18

What is a quantal response?

Answer 18

Yes-or-no response ex. death, molecular channel opening

Question 19

Describe an addition interaction between 2 chemicals:

Answer 19

A(1) + B(2) = response(3)
Straighforward adding

Question 20

Describe a synergistic interaction between 2 chemicals:

Answer 20

Enhanced A (3) + enhanced B (4) = enhanced response (7)
Both increase each other’s effects

Question 21

Describe a potentiation interaction between 2 chemicals:

Answer 21

Enhanced A + newly on C = new response
A normally inactive chemical (C) activates, also potentiates the effects of A

Question 22

Describe an antagonist interaction between 2 chemicals:

Answer 22

A (diminished) + B (diminished) = diminshed response

Question 23

What are NEDs?

Answer 23

Normal equivalent deviations: % of responses relative to the mean

Question 24

Formula for calculating probits:

Answer 24

NED + 5 = probits

Question 25

At 50%, what is the NED?

Answer 25

0, because there is no deviation from the mean

Question 26

Where is +1 and -1 SD from the mean?

Answer 26

84% and 16%

Question 27

Which probit value can do used to calculate LD/ED/TD50?

Answer 27

5, because it corresponds to NED = 0 = 50%

Question 28

Formula for calculating TI:

Answer 28

TI = LD50/ED50

Question 29

Formula for calculating MOS:

Answer 29

TD1/ED99

Question 30

A steeper slope for MOS is (better/worse)

Answer 30

Better, more safe, lesser overlap between TD and ED

Question 31

Why is MOS a more conservative estimate of a chemical's safety?

Answer 31

Takes the individual slopes of ED and TD into account, seeing where they meet