health problems and remedies: 2020

Wednesday 20 May 2020

Gupta’s Series 10: TOXICOLOGY Question and Answer bank

Prof PK Gupta Toxicologist

TOXICOLOGY Question and Answer bank

The MCQ's are aimed to make the study of toxicology simple and understandable ----------------

Exercise 1

1. Which one of the following statements regarding toxicology is true?

a. Modern toxicology is concerned with the study of the adverse effects of chemicals on ancient forms of life.

b. Modern toxicology studies embrace principles from such disciplines as biochemistry, botany, chemistry, physiology, and physics.

c. Modern toxicology has its roots in the knowledge of plant and animal poisons, which predates recorded history and has been used to promote peace.

d. Modern toxicology studies the mechanisms by which inorganic chemicals produce advantageous as well as deleterious effects.

e. Modern toxicology is concerned with the study of chemicals in mammalian species.

2. Knowledge of the toxicology of poisonous agents was published earliest in the:

a. Ebers papyrus.

b. De Historia Plantarum.

c. De Materia Medica.

d. Lex Cornelia.

e. Treatise on Poisons and Their Antidotes.

3. Paracelsus, physician- alchemist, formulated many revolutionary reviews that remain integral to the structure of toxicology, pharmacology, and therapeutics today. He focused on the primary toxic agent as chemical entity and articulated the dose–response relation. Which one of the following statements is not attributable to Paracelsus?

a. Natural poisons are quick in their onset of actions.

b. Experimentation is essential in the examination of

responses to chemicals.

c. One should make distinction between the therapeutic and toxic properties of chemicals.

d. These properties are sometimes but not always indistinguishable except by dose.

e. One can ascertain a degree of specificity of chemicals and their therapeutic or toxic effects.

4. The art of toxicology requires years of experience to acquire, even though the knowledge base facts may be learned more quickly. Which modern toxicologist is credited with saying that “you can be toxicologist in two easy lesions, each of 10 years?”

a. Claude Bernard.

b. Rachel Carson.

c. Upton Sinclair.

d. Arnold Lehman.

e. Oswald Schmiedeberg.

5. Which of the following statements is correct?

a. Claude Bernard was a prolific scientist who trained over 120 students and published numerous contributions to the scientific literature.

b. Louis Lewin trained under Oswald Schmiedeberg

and published much of the early work on the toxicity

of narcotics, methanol, and chloroform.

c. An Introduction to the Study of Experimental Medicine was written by the Spanish physician Orfila.

d. Magendie used autopsy material and chemical analysis systematically as legal proof of poisoning.

e. Percival Potts was instrumental in demonstrating the chemical complexity of snake venoms.

Answers

1. b.

2. a.

3. a.

4. d.

5. b.

Exercise 2

1. Five identical experimental animals are treated with 1 mg of one of the following toxins. The animal treated with which toxin is most likely to die?

a. ethyl alcohol (LD50 = 10,000 mg/kg).

b. botulinum toxin (LD50 = 0.00001 mg/kg).

c. nicotine (LD50 = 1 mg/kg).

d. ferrous sulfate (LD50 = 1500 mg/kg).

e. picrotoxin (LD50 = 5 mg/kg).

2. Place the following mechanisms of toxin delivery in order from most effective to least effective—1: intravenous; 2: subcutaneous; 3: oral; 4: inhalation; 5: dermal.

a. 1, 5, 2, 4, 3.

b. 4, 1, 2, 3, 5.

c. 1, 4, 2, 3, 5.

d. 4, 2, 1, 5, 3.

e. 1, 4, 3, 2, 5.

3.A toxin with a half -life of 12 h is administered every 12 h. Which of the following is true?

a. The chemical is eliminated from the body before the next dose is administered.

b. The concentration of the chemical in the body will

slowly increase until the toxic concentration is attained.

c. A toxic level will not be reached, regardless of how many doses are administered.

d. Acute exposure to the chemical will produce immediate toxic effects.

e. The elimination rate of the toxin is much shorter than the dosing interval.

4. Urushiol is the toxin found in poison ivy. It must first react and combine with proteins in the skin in order for the immune system to recognize and mount a response against it. Urushiol is an example of which of the following?

a. antigen.

b. auto-antibody.

c. superantigen.

d. hapten.

e. cytokine.

5. Toxic chemicals are most likely to be biotransformed in which of the following organs?

a. central nervous system.

b. heart.

c. lung.

d. pancreas.

e. liver.

6. When chemicals A and B are administered simultaneously, their combined effects are far greater than the sum of their effects when given alone. The chemical interaction between chemicals A and B can be described as which of the following?

a. potentiative.

b. additive.

c. antagonistic.

d. unctionally antagonistic.

e. synergistic.

7. With respect to dose–response relationships, which of the following is true?

a. Graded dose–response relationships are often

referred to as “all or nothing” responses.

b. Quantal dose–response relationships allow for the

analysis of a population’s response to varying dosage.

c. Quantal relationships characterize the response of an individual to varying dosages.

d. A quantal dose–response describes the response of an individual organism to varying doses of a chemical.

e. The dose–response always increases as the dosage is increased.

8. When considering the dose–response relationship or an essential substance:

a. there are rarely negative effects of ingesting too much.

b. the curve is the same or all people.

c. adverse responses increase in severity with increasing or decreasing dosages outside of the homeostatic range.

d. the relationship is linear.

e. deficiency will never cause more harm than over- ingestion.

9. The therapeutic index of a drug:

a. is the amount of a drug needed to cure an illness.

b. is lower in drugs that are relatively safer.

c. describes the potency of a chemical in eliciting a

desired response.

d. describes the ratio of the toxic dose to the therapeutic dose of a drug.

e. explains the change in response to a drug as the dose is increased.

10. Penicillin interferes with the formation of peptidoglycan cross-links in bacterial cell walls, thus weakening the cell wall and eventually causing osmotic death of the bacterium. Which of the following is true?

a. Treatment with penicillin is a good example of selective toxicity.

b. Penicillin interferes with human plasma membrane structure.

c. Penicillin is a good example of a drug with a low

therapeutic index.

d. Penicillin is also effective in treating viral infections.

e. Penicillin is completely harmless to humans

Answers

1. b.

2. c.

3. b.

4. d.

5. e.

6. e.

7. b.

8. c.

9. d.

10. a.

First edition published 2020 by CRC Press 6000 Broken Sound Parkway NW, Suite 300,Boca Raton, FL 33487-2742

Preface ix

Author xi

Section 1: General toxicology

Chapter 1 Principles of Toxicology 3

Chapter 2 Disposition and Toxicokinetics 21

Chapter 3 Mechanistic Toxicology 45

Section 2: Organ toxicity

Chapter 4 Target Organ Toxicity 65

Section 3: Non-organ-directed toxicity

Chapter 5 Carcinogenicity and Mutagenicity 101

Section 4: Toxic agents

Chapter 6 Toxic Effects of Pesticides and Agrochemicals 119

Chapter 7 Toxic Effects of Metals and Micronutrients 135

Chapter 8 Toxic Effects of Non-metals and Micronutrients 151

Chapter 9 Toxicological Hazards of Solvents, Gases, Vapours,

and Other Chemicals 155

Chapter 10 Hazards of Radiation and Radioactive Materials 163

Chapter 11 Toxicities from Human Drugs 169

Section 5: Plants

Chapter 12 Toxic Effects of Plants 177

Section 6: Poisonous organisms, food and feed toxicity

Chapter 13 Biotoxins and Venomous Organisms 199

Chapter 14 Food Hazards and Feed-Contaminant Toxicity 207

Chapter 15 Mycotoxicoses 221

Section 7: Environmental toxicology

Chapter 16 Pollution and Ecotoxicology 231

Section 8: Applications in toxicology

Chapter 17 Forensic and Clinical Toxicology 255

Section 9: Special topics

Chapter 18 Adverse Effects of Calories 293

Chapter 19 Toxic Effects of Nanoparticles 297

Chapter 20 Occupational Toxicology 301

Chapter 21 Veterinary Drug Residue Hazards 305

PREFACE

This book entitled Brain Storming Questions in Toxicology serves as a comprehensive and quick reference for various examinations. This book contains multiple-choice questions, true or false/correct or incorrect statements, and match the correct statement, which are widely used in entrance tests, competitive examinations, and at some places in certifying examinations. It is therefore of utmost importance to induct items that not only tests the knowledge, understanding, and application ability of the student but also helps in learning objectives, methods of self-study, and selfassessment. Solving such brainstorming questions could help the crystallization and assimilation of the fundamental principles and applications in drug toxicology, clinical pharmacology, clinical toxicology, and medical toxicology, and for forensic toxicologists, environmentalists, and veterinarians.

Thus, this book will be a useful tool and essential guide for those who want to prepare for licensure and certification exams, persons seeking continuing education, etc. This will also serve as a refresher for academicians and professionals in the field. With these objectives, the book has been divided in several chapters that cover the general principles of toxicology, disposition and kinetics, mechanistic toxicology, target and non-target-directed toxicity, and the toxic effects of various xenobiotics, such as pesticides, metals and micronutrients, non-metals, solvents, gases and vapours, poisonous and venomous organisms, toxicity from humanuse drugs, plant toxins, food and feed contaminants, radiation and radioactive materials, adverse effects of pollution and ecotoxicology, forensic and clinical toxicology, adverse effects of calories, toxic effects of nanomaterials, occupational exposure, and residual drug toxicity. Each chapter is in the format of objective questions and answers; thus, it is a unique book in toxicology that reflects the breadth and multidisciplinary nature of toxicology with an objective approach to the subject.

In brief, the book is an essential guide and has been specifically targeted for a very specific audience of students, teachers, and established toxicologists. Therefore, the author believes that this book will serve the students, academic institutions, and industry as follows:

• It is an excellent contribution for the students who need a study aid for toxicology but wants more than a textbook because they need a self-testing regime.

• It will be a useful tool for the teachers of toxicology who need inspiration when composing questions for their students.

• It will also help established toxicologists test their own knowledge of understanding the subject matter.

• It will be useful at universities and colleges and in industry for in-house training courses in toxicology, which I know exist in some pharmaceutical and chemical companies.

• It is required for all those who want to study for the toxicology boards and other examinations.

Thus, the main strength of this book is to improve the engagement and understanding of the subject. Toxicology is a rapidly evolving field. Suggestions and comments are welcome to help the author improve the contents of the book. Please also suggest the deficiencies that need to be covered at drpkg_brly@yahoo.co.in or drpkg1943@gmail.com if you have any topics you feel should be better covered in any future editions.

P. K. Gupta

Chapter 1

PRINCIPLES OF TOXICOLOGY

1.1 MULTIPLE-CHOICE QUESTIONS(Choose the most appropriate response.)

Exercise 1

Q.1. ‘It is the dose that differentiates a toxicant from a poison.’ This statement was made

by scientist ________.

a) Paracelsus

b) Hippocrates

c) Socrates

d) Homer

Q.2. The branch of science that deals with assessing the toxicity of substances of plant and animal

origin and those produced by pathogenic bacteria is ________.

a) toxicology

b) toxinology

c) toxicokinetics

d) toxicodynamics

Q.3. Minimum dose of a toxicant producing the desired response is called ________.

a) ceiling dose

b) threshold dose

c) both a and b

d) none

Q.4. The Arthus reaction is seen in the hypersensitivity of ________.

a) type I

b) type II

c) type III

d) type IV

Q.5. The Coolie breeds of dogs are hypersensitive to ________.

a) Albendazole

b) Ivermectin

c) both

d) none

Q.6. The measure of the margin of safety of a toxicant is obtained by ________.

a) LD50/ED 99

b) LD 1/ED 99

c) ED50/LD 50

d) LD50/ED 50

Q.7. A substance is called as moderately toxic if its median lethal dose is ________.

a) 1–5 mg

b) 5–500 mg

c) 0.5–1 g

d) >1 g

Q.8. A toxic substance produced by a biological system is specially referred to as a ________.

a) toxicant

b) toxin

c) xenobiotic

d) poison

Q.9. Allergic contact dermatitis is ________.

a) a non-immune response caused by a direct action of an agent on the skin

b) an immediate type-I hypersensitivity reaction

c) a delayed type-IV hypersensitivity reaction

d) characterized by the intensity of reaction being proportional to the elicitation dose

e) not involved in photoallergic reactions

Q.10. The reference dose (RfD) is generally determined by applying which of the following

default procedures?

a) An uncertainty factor of 100 is applied to the NOAEL in chronic animal studies

b) A risk factor of 1000 is applied to the NOAEL in chronic animal studies

c) A risk factor of 10,000 is applied to the NOAEL in subchronic animal studies

d) An uncertainty factor between 10,000 and 1 million is applied to the NOEL from

chronic animal studies

e) Multiplying the NOAEL from chronic animal studies by 100

Q.11. Which of the following concerning the use of the ‘benchmark dose’ in risk assessment is

not correct?

a) Can use the full range of doses and responses studied

b) Allows use of data obtained from experiments where a clear ‘no observed adverse

effect level’ (NOAEL) has been attained

c) May be defined as the lower confidence limit on the 10% effective dose

d) Is primarily used for analyses of carcinogenicity data and has limited utility for analyses

of developmental and reproduction studies that generate quantal data

e) Is not limited to the values of the administered doses

Q.12. Administration by oral gavage of a test compound that is highly metabolized by the liver

versus subcutaneous injection will most likely result in ________.

a) less parent compound present in the systemic circulation

b) more local irritation at the site of administration caused by the compound

c) lower levels of metabolites in the systemic circulation

d) more systemic toxicity

e) less systemic toxicity

Q.13. The phrase that best defines ‘toxicodynamics’ is the ________.

a) linkage between exposure and dose

b) linkage between dose and response

c) dynamic nature of toxic effects among various species

d) dose range between desired biological effects and adverse health effects

e) loss of dynamic hearing range due to a toxic exposure

Q.14. Which of the following was banned under the Delaney Clause of the Food Additive

Amendment of 1958?

a) Butylated hydroxytoluene

b) Sulfamethazine

c) Cyclamate

d) Phytoestrogens

e) Aflatoxin

Q.15. Which of the following toxicity can occur from a single exposure?

a) Acute toxicity

b) Subacute toxicity

c) Subchronic toxicity

d) Chronic toxicity

Q.16. Which of the following assumptions is not correct regarding risk assessment for male

reproductive effects in the absence of mechanistic data?

a) An agent that produces an adverse reproductive effect in experimental animals is

assumed to pose a potential reproductive hazard to humans.

b) In general, a non-threshold is assumed for the dose-response curve for male reproductive

toxicity.

c) Effects of xenobiotics on male reproduction are assumed to be similar across species

unless demonstrated otherwise.

d) The most sensitive species should be used to estimate human risk.

e) Reproductive processes are similar across mammalian species.

Q.17. A newly formed hapten protein complex usually stimulates the formation of a significant

amount of antibodies in ________.

a) 1–2 min

b) 1–2 hours

c) 1–2 days

d) 1–2 weeks

Q.18. Prolonged muscle relaxation after succinylcholine is an example of a/an ________.

a) IGE-mediated allergic reaction

b) idiosyncratic reaction

c) immune complex reaction

d) reaction related to a genetic increase in the activity of a liver enzyme

Q.19. Increased production of methemoglobin is due to decreased activity of ________.

a) cytochrome P450 2B6

b) NADH cytochrome b5 reductase

c) cytochrome oxidase

d) cytochrome a3

Q.20. The most common target organ of toxicity is the ________.

a) heart

b) lung

c) CNS (brain and spinal cord)

d) skin

Answers

1. a 6. d 11. d 16. b

2. b 7. b 12. a 17. c

3. b 8. b 13. b 18. d

4. c 9. c 14. c 19. b

5. b 10. a 15. a 20. c

health problems and remedies

Wednesday 20 May 2020

Gupta’s Series 10: TOXICOLOGY Question and Answer bank

Further Reading

Gupta's Series 18: Brain Storming Questions in Toxicology : MCQ's

First edition published 2020 by CRC Press 6000 Broken Sound Parkway NW, Suite 300,Boca Raton, FL 33487-2742

CONTENTS

Preface ix

Author xi

Section 1: General toxicology

Section 2: Organ toxicity

Section 3: Non-organ-directed toxicity

Section 4: Toxic agents

Section 5: Plants

Section 6: Poisonous organisms, food and feed toxicity

Section 7: Environmental toxicology

Section 8: Applications in toxicology

Section 9: Special topics

PREFACE

Chapter 1

PRINCIPLES OF TOXICOLOGY