General Toxicology

Question 1

Toxicology

Answer 1

Study of poisons - identification of poisons, their chemical properties, their biologic effects as well as the treatments of disease conditions that they cause

Question 2

Poison

Answer 2

any liquid, solid, or gas (oral or topical) that can interfere with life processes of cells; aka toxicant

Question 3

Toxin

Answer 3

poisons that originate from biologic processes; classified as biotoxins

Question 4

Toxic

Answer 4

effects of poison on living system

Question 5

Toxicosis

Answer 5

Disease state that results from exposure to a poison

Question 6

Toxicity

Answer 6

The amount of poison that, under a specific set of conditions, causes toxic effects or results in detrimental biologic changes. (Note - in wildlife/aquatics this may be expresses as the concentration of the substance in feed or water; diff from dosage which is directly correlated with concentration when material is freely available)

Question 7

Threshold Dose

Answer 7

A toxic or adverse reaction to a chemical where above this has detrimental effects that can be measured

Question 8

Graded response

Answer 8

increase in degree or severity as the amount/dosage of toxicant increases

Question 9

Dosage

Answer 9

Amount of toxicant per unit of animal weight (typically mg/kg)

Question 10

Dose

Answer 10

Total amount of toxicant received per animal

Question 11

Lethal Concentration (LC)

Answer 11

lowest concentration of compound in feed (or water fish) that causes death; mg/kg

Question 12

Acute lethal toxicity (LC50)

Answer 12

concentration of compound in feed/water that will kill 50% of animals exposed; AKA median lethal dose

Question 13

Highest Nontoxic Dose (HNTD)

Answer 13

Largest dose that does not result in clinical of pathological

Question 14

Toxic Dose-Low (TDL)

Answer 14

Lowest dose that will produce alterations; administration of twice this dose is not lethal

Question 15

Toxic Dose-High (TDH)

Answer 15

dose that will produce drug-induced alterations and administration of twice this dose is lethal

Question 16

Lethal Dose (LD)

Answer 16

Lowest dose that causes death in any animal during the period of observation. (Various percentages can be attached to the LD value to indicate doses required to kill 1% (LD1), 50% (LD50), 100% (LD100)

Question 17

Median lethal dose (MLD)

Answer 17

concentration of compound in feed/water that will kill 50% of animals exposed; AKA LD50

Question 18

Effective Dose 50 (ED50)

Answer 18

dosage of a drug or therapeutic agent that produces the desired effect in half of a population

Question 19

Therapeutic Index (TI)

Answer 19

TI=LD50/ED50

Question 20

Standard Safety Margin (SSM)

Answer 20

SSM=LD1/ED99 More conservative estimate than TI

Question 21

Extremely toxic

Answer 21

<1 mg/kg

Question 22

Highly Toxic

Answer 22

1-50 mg/kg

Question 23

Moderately toxic

Answer 23

50-500 mg/kg

Question 24

Slightly toxic

Answer 24

0.5-5 g/kg

Question 25

Practically nontoxic

Answer 25

5-15 g/kg

Question 26

Relatively harmless

Answer 26

>15 g/kg

Question 27

Acute toxicity

Answer 27

describes effects of a single dose or multiple doses during a 24-hour period

Question 28

Subacute Toxicity

Answer 28

refers to repeated exposure and effects observed for 30 days or less

Question 29

Subchronic Toxicity

Answer 29

Study of exposure and effects for 1-3 months; studies of 3 months are considered adequate to express all forms of toxicosis except carcinogenic effects and multigenerational effects

Question 30

Chronic Toxicity

Answer 30

Produced by prolonged exposure for 3 months or longer

Question 31

Lethal Dose 50 (LD50)

Answer 31

a dosage that is lethal to 50% of animals exposed to a specific toxicant under defined conditions, including species, route of exposure, and duration of exposure

Question 32

Tolerance

Answer 32

due to prolonged exposure to a toxicant, the size of the dose required to produce lethality upon repeated exposure increases

Question 33

Chronicity factor

Answer 33

ratio of acute to chronic LD50; greater than 2.0 indicates a cumulative factor

Question 34

Hazard

Answer 34

the probability that a chemical will cause harm under specific conditions of use; aka risk

Question 35

Toxicokinectics

Answer 35

movement and disposition of toxicants in the organism

Question 36

Response to chemicals is affected by toxicokinetic influence on?

Answer 36

Rate and amount of absorption Distribution of chemical within the body Biotransformation Rate of excretion

Question 37

Passive transport

Answer 37

most common toxicant transport; move across membranes along a concentration gradient

Question 38

Active transport

Answer 38

a specialized form of membrane passage; move against a concentration gradient; metabolic energy required; competitive inhibition can occur

Question 39

Facilitated diffusion

Answer 39

not common for xenobiotics (foreign chemicals); has some characteristics of both passive diffusion and active transport; compounds move along a concentration gradient; energy not required; transport system can be saturated

Question 40

Volume of distribution (VD)

Answer 40

the fluid volume in whcih a chemical seems to be dissolved | VD=(weight of chemical distributed in the body)/(Plasma concentration of chemical at equilibrium)

Question 41

Excretion

Answer 41

typically from kidneys (urine) and liver (bile); can from lungs, intestines, sweat, saliva, and milk

Question 42

Routes of elimination

Answer 42

Renal (glomerular filtration or active tubular)

Question 43

Clearance

Answer 43

volume of plasma cleared of a specific xenobiotic each minute Clearance = (urinary drug concentration (mg/ml) x urine flow rate (ml/min)/(plasma drug concentration (mg/ml)

Question 44

Rate of elimination

Answer 44

typically exponential and called 'first-order' elimination

Question 45

Half-life

Answer 45

time needed for one-half of a chemical to be eliminated from the body; Cr+Cie^(-kt) ; Cr = concentration remaining; Ci= initial concentration; k=elimination rate constant for a tissue, toxicant and species; t = time in hours or days