Introduction to Toxicology

Question 1

Toxicology

What is the common defintion of Toxicology, and why is it important for public understanding?

Answer 1

• The science of poisons and their antidotes
• A common defintion makes this concept accessible to the public and in turn the public can understand the basic idea of how chemicals may be harmful.

Question 2

Toxicology

What is the scientific definition of toxicology, and what is the role of toxicologists?

Answer 2

• The study of the adverse effects of agents on living organisms
• To study these effects and the probability of their occurence.

Question 3

Toxin vs. Toxicant

What is a toxin, and how does it differ from a toxicant?

Answer 3

• A toxin is produced naturally by organisms (microbes, plants, and animals) and interacts with cellular components to kill cells, alter growth or development, or kill the organism.
• A toxicant is produced as a by product of human made activities (industrial chemicals, pesticides, radon etc.) . These agents can kill humans, animals, and/or plants.

Question 4

Toxin vs. Toxicant

What are some examples of natural sources that produce toxins?

Answer 4

Microbial organisms: bacteria
Plants: poison ivy
Animals: snake venom

Question 5

Goals of Toxicology

What are the three goals of Toxicology?

Answer 5

1. Better understand the biological effects of chemicals
2. Obtain relevant data for decisions concerning public, environmental, and occupational health risks
3. Create a better informed public that is able to make sensible personal choices.

Question 6

Toxicologists organize chemicals

How does classifying chemicals by target organ help toxicologists in assessing their effects?

Answer 6

• identify most affected organ systems by chemicals
• develop targeted studies or establish preventative measures

Question 7

Toxicologists organize chemicals

What is the significance of classifying chemicals by their use, such as biocides or solvents?

Answer 7

• identify their usage and associated risks
• handling practices and regulatory measures

Question 8

Toxicologists organize chemicals

Why might a toxicologist classify a chemical based on its adverse effect, such as causing cancer?

Answer 8

• long-term health risks
• minimize exposure to carcinogens

Question 9

Toxicologists organize chemicals

How does knowing the physical state of a chemical (solid, liquid, gas) influence its toxicity assessment?

Answer 9

• tells how the chemical can be absorbed, distributed, and/or excreted

Question 10

Toxicologists organize chemicals

What does it mean for a chemical to be classified by its toxic potency?

Answer 10

• level of exposure required to cause harm
• establish safety thresholds and exposure limits

Question 11

Toxicologists organize chemicals

How does classifying chemicals by their mechanism of action, like cholinesterase inhibitors, aid in understanding their toxic effects?

Answer 11

• how the chemical interacts biologically
• development of antidoted or treatments

Question 12

Toxicologists organize chemicals

Why is it useful to classify chemicals based on their structure or chemical type, such as organophosphates or metals?

Answer 12

• predict chemical behavior
• better risk assessments and management

Question 13

Toxicologists organize chemicals

What role does classifying chemicals by their source (air, water, food) play in exposure assessment?

Answer 13

• pathways of exposures
• targeted monitoring and mitigation techniques

Question 14

Xenobiotics vs. endogenous chemicals

What is a Xenobiotic, and how does it differ from an endgoneous chemical? What are synthetic chemicals?

Answer 14

• A xenobiotic is any substance that is foreign to the body.
• Endgoneous chemicals are naturally occuring toxins
• Synethetic chemicals are man made toxins that are not naturally occuring

T/F: Endgoneous chemicals are never toxic

Question 15

Modern Toxicological Concepts

Who said this quote, and what does it mean: “All substances are poisons: there is none which is not a poison. The right dose differentiates a poison and a remedy”.

Answer 15

• Paracelus, the Father of Toxicology
• The dosage of the substance will make the substance toxic

Question 16

Modern Toxicological Concepts

What does the term “toxicon” refer to in modern toxicological concepts?

Answer 16

• The toxic agent in a substance that causes adverse effects associated with a chemical entity

Question 17

Who said this quote, and what does it mean: “All substances are poisons: there is none which is not a poison. The right dose differentiates a poison and a remedy”.

Answer 17

• Paraceleus, the Father of Toxicology
• The dosage substances make the substance toxic

Question 17

Modern Toxicological Concepts

________ are essential in studying the responses of chemicals

Answer 17

• Experiments

Question 18

Modern Toxicological Concepts

How can toxicologists distinguish between therapeutic and toxic responses to chemicals?

Answer 18

• Studying dose-response relationships, understanding the chemical’s mechanism of action, and identifying the specific effects at different concentrations.

Question 19

Modern Toxicological Concepts

How does dose influence whether a chemical will have a therapeutic or toxic effect?

Answer 19

The dose determines which effect will predominate; a low dose may be therapeutic, while a high dose may lead to toxicity.

Question 20

Modern Toxicological Concepts

What is meant by the specificity of chemicals in terms of therapy and toxicity?

Answer 20

• The idea that certain chemicals are designed to have therapeutic effects on specific targets, but they can also cause toxicity if they interact with unintended targets or at excessive doses

Question 21

History of Poisons and “Poisoners”

What was King Mithridates’ primary goal in relation to poisons?

Answer 21

• Sought immunity from poisons, including arsenic, developed a tolerance through gradual self administered dosages

Question 22

History of Poisons and “Poisoners”

What is Mithridatization, and how does it relate to the theory of hormesis?

Answer 22

• The practice of developing immunity to toxins through gradual self exposure
• The theory that exposure of low doses of a toxic substance can build resistance and/or tolerance

Question 23

# History of Poisons and "Poisoners" What role did Queen Catherine play in the context of poisoning and toxicology?

Answer 23

* used poisoners for hire to poison unvoluntary peasants

Question 24

# History of Poisons and "Poisoners" What methods did historical figures like the British surgeon **and** French chemist use to address poisoning?

Answer 24

* Opium and lavage (stomach pumping * Combination of arsenic and charcoal

Question 25

# The Modern Era: Concerns for Low Level Exposures in Larger Populations –

Question 26

# The Modern Era: Concerns for Low Level Exposures in Larger Populations – How did concerns for cancer-causing agents in the environment evolve in the post-WWII era?

Answer 26

* Focus shifted to identifying and regulating enviornmental pollutants that could cause or contribute to cancer

Question 27

# The Modern Era: Concerns for Low Level Exposures How did the publication of "Silent Spring" in 1962 influence environmental health concerns?

Answer 27

* This film raised awareness on the harmful effects of pesticides on public and environmental health

Question 28

# The Modern Era: Concerns for Low Level Exposures What was the significance of the founding of the Environmental Protection Agency (EPA) in 1970?

Answer 28

* address and regulate enviornmental health concerns * regulate pollution, enforce laws, protect the public and environment from harmful chemicals

Question 29

# The Modern Era: Concerns for Low Level Exposures What role does the Society of Toxicology (founded in 1961) play in the field of toxicology?

Answer 29

* advancement of the science of toxicology

Question 30

# The Modern Era: Concerns for Low Level Exposures Why is 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), commonly known as dioxin, significant in toxicology?

Answer 30

* TCDD is a highly toxic environmental contaminant that can cause cancer and chronic diseases

Question 31

# Forensic Toxicology What role does forensic toxicology play in the medico-legal context?

Answer 31

* examines harmful effects of chemicals on humans and animals to support legal investigations and cases by determining if the poisoning or chemical exposure contributed to death * utilizes analytical chemistry for determining exposure levels and confirming the presence of toxins

Question 32

# Forensic Toxicology/Legal Consultation What is the role of a forensic toxicologist in medical torte litigation

Answer 32

* provide a testimoney for medical cases by explaining the harmful effects of chemicals and the role they played in death or injury, if any at all

Question 33

# Public Health What role does **epidemiology** play in the public health perspective on chemical exposure?

Answer 33

* studies the relationship between chemical exposures and health outcomes; studies the effects of exposure-related diseases

Question 34

# Public Health Why is understanding **dose-response relationships** important in toxicology from a public health perspective

Answer 34

* dose response relationships help us find the point at which we see adverse effects; critical for setting exposure limits and developing safety guidelines

Question 35

# Public Health How does** industrial hygiene and occupational safety **contribute to managing chemical hazards in the workplace?

Answer 35

* assess the consquences of workplace chemical exposures; needed for implementing control measures

Question 36

# Public Health How do toxicology, epidemiology, and industrial hygiene work together to address chemical hazards in public health?

Answer 36

* chemical effects on dose-responses, chemical exposure health consquences, controlling workplace chemical exposures - protecting public health

Question 37

What is a hazard, and how does it differ from a risk

Answer 37

* the capacity to cause adverse effects * the probability of adverse effects under certain conditions

Question 38

# US Environmental Protection Agency (EPA) What is the primary focus of the **Toxic Substances Control Act (TSCA) of 1976**?

Answer 38

* regulate industrial chemicals, restrict use, and require testing if risks are expected

Question 39

# US Environmental Protection Agency (EPA) What does the 90-day premanufacture notification requirement under TSCA entail?

Answer 39

* Manufacturers must notify EPA 90 days before production of a new chemical, this allows EPA to assess potential risks

Question 40

# US Environmental Protection Agency (EPA) What role do the Clean Air Act and its amendments play in regulating hazardous air pollutants (HAPs)?

Answer 40

* identified and regulated 186 harmful air polluntants (HAPS) to protect public health and environmental from harmmful air emissions

Question 41

# US Environmental Protection Agency (EPA) How do the Clean Air Act and its amendments ensure the safety of regulated air pollutants?

Answer 41

* Identified 186 HAPS * Requires toxicity tests

Question 42

# US Environmental Protection Agency (EPA) How do the Toxic Substances Control Act and the Clean Air Act **differ** in their regulatory focus?

Answer 42

* TSCA regulates industrial chemicals and their uses, require premanufaction notifications and risk assessments. * Clean Air Act controls HAPS and ensures air quality through toxicity testing and emission standards

Question 43

# Agency for Toxic Substances and Disease Registry How does the ATSDR assess the impact of hazardous substances at waste sites?

Answer 43

* conducts public health assessments to evaluate potential health risks posed by hazadrous substances at waste sites

Question 44

# Agency for Toxic Substances and Disease Registry What is the primary mission of the Agency for Toxic Substances and Disease Registry (ATSDR)?

Answer 44

* serve the public by using the best science * take responsive public health actions * provide trusted health information to prevent harmful exposures and diseases related to toxic substances

Question 45

# Agency for Toxic Substances and Disease Registry What are the specific functions of ATSDR in relation to public health and hazardous substances?

Answer 45

* applied research * public health assessments of waste sites * develops information, education, and training to protect public health

Question 46

# US Food and Drug Administration What was the primary purpose of the **Food and Drugs Act of 1906**?

Answer 46

* prohibit the interstate transport of misbranded and adulterated foods, drinks, and drugs; protected consumers from unsafe or fraudulent products

Question 47

# US Food and Drug Administration What significant requirements were introduced by the **Food, Drug, and Cosmetic Act (FDCA) of 1938**?

Answer 47

* Safety and efficacy testing required

Question 48

# US Food and Drug Administration What did the **Food Additives Amendment of 1958 **require regarding food additives?

Answer 48

* Prior testing before approval

Question 49

# US Food and Drug Administration What is the **Delaney Clause**, and what does it prohibit?

Answer 49

* Provision of the Food Additives Amendment * Bans carcinogenic substances as food additives

Question 50

# Mechanistic Toxicology What is the primary **focus** of mechanistic toxicology?

Answer 50

* focuses on identifying and understanding the cellular, biochemical, and molecular mechanisms by which chemicals exert toxic effects on living organisms

Question 51

# Mechanistic Toxicology What role does mechanistic toxicology play in **identifying susceptible populations**?

Answer 51

* Through toxicogenomics and molecular epidemiology * Mechanistic toxicology helps identify genetic or molecular markers that make certain populations more susceptible to toxic effects, enabling personalized risk assessments and interventions.

Question 52

# Mechanistic Toxicology What are some key applications of mechanistic toxicology studies

Answer 52

* risk assessment * determining human relevance of toxic effects, developing safer drugs * identifying susceptible populations through toxicogenomics and molecular epidemiology * contributing to fundamental biological research

Question 53

# Mechanistic Toxicology Why is mechanistic toxicology important for fundamental biological **research**?

Answer 53

* deeper understanding of basic biological processes and how they are disrupted by toxic chemicals

Question 54

# Mechanistic Toxicology How do mechanistic studies aid in the **development of safer drugs**?

Answer 54

* minimize toxicity while maintaining therapeutic efficacy

Question 55

# Mechanistic Toxicology Why is the **determination of human relevance** important in mechanistic toxicology?

Answer 55

* to assess whether the toxic effects observed in animal models or in vitro studies are applicable to humans

Question 56

# Mechanistic Toxicology How does mechanistic toxicology contribute to risk assessment?

Answer 56

* detailed insights into how chemicals cause harm at a molecular level