Toxic Substances – Chapter 1: Overview of Toxic Substances

Toxic Substances – Chapter 1: Overview of Toxic Substances

1. What do Toxic Substances Do?

• Properties of Toxic Substances: Toxic substances are materials capable of altering physiological functions at various levels upon exposure to the body at low doses.

• Detection Methods: Identifying toxic substances in the environment and the body, and determining the level of contamination.

• Assessing the Level of Toxicity: Evaluating the danger of a toxic substance based on the dose, duration of exposure, route of exposure, and health status of the exposed individual.

• Prevention: Establishing standards for toxic substances, monitoring compliance with these standards, refining and developing analytical methods, and proposing detoxification methods to prevent environmental pollution.

2. Subjects of Toxicology

• Agents that are toxic to humans and animals: These include chemicals, biological agents, physical factors, etc., that impact health.

• Physical Agents: Radiation energy, temperature, pressure, noise, electricity, etc.

3. How do Toxic Substances Primarily Enter the Body?

• Directly: Through the digestive system, respiratory system, and skin. Regular monitoring of environmental pollution is crucial to limit direct exposure.

4. What Properties of Toxic Substances are Studied in Toxicology?

• Chemical and Biological: Investigating the chemical properties and biological effects of toxic substances.

5. What is the Most Important Task of Toxicology?

• Preventing Toxicity and Environmental Pollution: Establishing standards, monitoring, refining analytical methods, and proposing detoxification methods.

6. How Many Specific Tasks are Included in the Most Important Task?

• Four specific tasks:

• Establishing standards for toxic substances.

• Monitoring compliance with the standards.

• Refining and developing analytical methods.

• Proposing detoxification methods to prevent environmental pollution.

7. What is the Second Most Important Task of Toxicology?

• Supporting Emergency Care and Treatment: Identifying toxic substances and determining appropriate treatment methods.

8. What is the Third Most Important Task of Toxicology?

• Supporting Forensic Investigations: Determining the cause of death in suspected poisoning cases.

9. What are Toxic Substances?

• Toxic Substances: Materials that can cause alterations in physiological functions at various levels upon exposure to the body at low doses.

10. What Factors Influence the Toxicity of a Substance?

• Toxicity depends on: Dose, solubility, dispersion, age, physical condition, health status, etc.

11. Is BaCl2 or BaSO4 More Toxic?

• BaCl2 is more toxic than BaSO4: Because BaCl2 is soluble in water and easily absorbed by the body.

12. As the Dispersion of Mercury Increases, Toxicity…?

• Increases: Higher dispersion allows mercury to more easily penetrate the body.

13. What does Toxicity Characterize?

• Toxicity characterizes: The concept of dosage to describe the toxic properties of a substance.

14. What is LD?

• LD (Lethal Dose): The lowest dose that can cause death in laboratory animals.

15. What is ED50?

• ED50 (Effective Dose 50%): The dose that produces a response in 50% of laboratory animals.

16. What is the Maximum Non-Toxic Dose?

• Maximum Non-Toxic Dose: The highest dose that does not cause physiological changes in the body.

17. What is the Minimum Toxic Dose?

• Minimum Toxic Dose: The dose that causes the first physiological changes but does not lead to death.

18. What is the Toxic Dose?

• Toxic Dose: The dose that can cause death if exposed for a short period.

19. How is LD Measured?

• LD is measured by: Oral administration and dermal exposure.

20. What is the Coefficient used when Measuring Toxicity through the Respiratory System?

• EC (Effective Concentration): Indicates the concentration of a toxic substance in the air that causes a specific effect.

21. What Subjective Factors Influence Toxicity?

• Species: Different species have varying sensitivities to toxic substances.

• Age: Children and the elderly are more sensitive than adults.

• Sex: Males and females may have different sensitivities.

• Body Weight: Body weight impacts the dose required to produce toxicity.

• Physical Condition: Individuals with illness, weakness, or compromised health are more susceptible to toxic effects.

• Individual Sensitivity: Differences in genetic makeup and immune response affect tolerance to toxic substances.

22. How Many Times Greater is the Toxic Dose of Atropine in Rabbits Compared to Humans? What About Morphine? What is the Reason?

• Atropine: 100 times greater due to rabbits possessing an enzyme that hydrolyzes atropine into tropanol and tropic acid.

• Morphine: 70 times greater.

23. In Which Toxic Substances are Children More Sensitive than the Elderly?

• Neurotoxins: Children are more sensitive to neurotoxins because their nervous systems are not fully developed.

24. In Which Toxic Substances are the Elderly More Sensitive than Children?

• Metabolism through the Liver and Kidneys: The elderly have reduced liver and kidney function, making it difficult to metabolize and eliminate toxic substances.

25. What Objective Factors Influence Toxicity?

• Route and Method of Administration: Intravenous injection, oral ingestion, inhalation, correct dosage, proper administration, appropriate dose, etc.

• Dosage Form: Solution, powder, tablets, etc.

• Rate of Drug Delivery to the Body: The faster the absorption, the stronger the toxicity.

• Simultaneous Use with Other Drugs: Drug interactions can increase or decrease toxicity.

• Drug Tolerance: The reason behind drug addiction.

26. Where do Organophosphates Typically Accumulate in the Body?

• Fat Tissues: Organophosphates are lipophilic, so they accumulate in fat tissues.

27. How are Toxic Substances Classified by Origin?

• Natural: From plants, animals, minerals, etc.

• Synthetic: Created from chemical reactions.

• Semi-synthetic: Derived from natural materials treated with chemical methods.

28. How are Toxic Substances Classified by Physicochemical Properties?

• Solid, Liquid, Gas.

• Inorganic Toxic Substances: Compounds that do not contain carbon, such as heavy metals, acids, bases, etc.

• Organic Toxic Substances: Compounds containing carbon, such as pesticides, herbicides, industrial chemicals, etc.

29. What Criterion is Used to Classify Toxic Substances by Toxicity?

• Lethal dose in a 70 kg human or LD50 of a single oral dose in rats.

30. How are Toxic Substances Classified Based on Sample Treatment and Analytical Methods?

• Water-soluble: Substances that readily dissolve in water are analyzed using common methods.

• Oil-soluble: Substances that readily dissolve in oil require special analytical methods.

31. What are Other Ways to Classify Toxic Substances?

• Site of Toxicity: Impact on the nervous system, liver, kidneys, cardiovascular system, etc.

• Effect of Toxic Substance: Acute toxicity, chronic toxicity, carcinogenicity, mutagenicity, etc.

• Purpose of Using Toxic Substances: Medicines, pesticides, herbicides, chemical weapons, etc.

32. What is Poisoning?

• Poisoning: Physiological changes under the influence of a toxic substance, resulting in dysfunction of the body.

33. What are the Causes of Poisoning?

• Mistakes: Confusing medicines, foods, chemicals, etc.

• Occupational Exposure: Regular contact with toxic substances during work.

• Environmental Pollution: Exposure to environments contaminated with toxic substances.

• Intentional or Poisoning: With the intent to harm others.

34. What is the Most Dangerous Type of Environmental Pollution?

• Water: Water is the source of drinking water and sanitation, so water contamination is extremely dangerous.

35. What Does the Level of Poisoning Depend On?

• Dose and Route of Administration: The higher the dose and the easier the absorption, the more severe the poisoning.

36. What is Acute Poisoning?

• Acute Poisoning: Symptoms appear quickly after one or a few exposures, usually within 24 hours.

37. What is Subacute Poisoning?

• Subacute Poisoning: Symptoms appear after a few days or weeks. Treatment is rapid, but residual effects can remain.

38. What is Chronic Poisoning?

• Chronic Poisoning: Occurs after repeated exposures, accumulating in the body. There may be no obvious symptoms, but it can cause changes in cell structure and function.

39. Where is the Main Distribution of Chlorine-Containing Hydrocarbons in Acute and Chronic Poisoning?

• Acute Poisoning: Neurotoxicity.

• Chronic Poisoning: Liver cancer.

40. What is the Primary Route of Absorption?

• Digestive System: The digestive system is the main route of absorption for toxic substances.

41. What is the Fastest Route of Absorption?

• Intravenous Injection and Lungs: Intravenous injection and the lungs are the fastest routes of absorption, as toxic substances enter the body directly.

42. Which Substances are Not Absorbed through the Skin?

• Water-soluble substances in ionic form: Water-soluble substances in ionic form are difficult to absorb through the skin.

43. What Factors Influence Skin Absorption?

• Molecular Size: Smaller molecules are more easily absorbed through the skin.

• Concentration: Higher concentrations of toxic substances lead to faster absorption.

• Area of Contact: The larger the area of contact, the more absorption.

• Moisture and Degree of Congestion: Moist and congested skin allows toxic substances to penetrate more easily.

44. What Factors Influence Absorption through the Digestive System?

• Concentration: The higher the concentration of the toxic substance, the more absorption.

• Size: Smaller molecules are more easily absorbed.

• Degree of Ionization: Non-ionized toxic substances are more easily absorbed.

• Solubility of the Molecule: Water-soluble toxic substances are more easily absorbed.

• pH of the Digestive System: The pH of the digestive system affects the solubility and absorption of toxic substances.

45. Do All Substances that Enter the Body through the Respiratory System Go Directly to the Lungs?

• Not all: Larger substances are retained in the throat, nose, and mouth. Only smaller substances reach the lungs.

46. Why is Absorption through the Respiratory System Fast?

• Lungs are well-perfused with blood and have thin alveolar walls: The lungs have a large surface area, receive abundant blood supply, and have thin alveolar walls, enabling easy absorption of toxic substances into the bloodstream.

47. What Factors Does Distribution Depend On?

• Physicochemical Properties of the Drug: Solubility, polarity, etc.

• Affinity of the Toxic Substance to Tissues: Toxic substances with a strong affinity to specific tissues will accumulate there more readily.

• Accumulation Capacity of Tissues: Some toxic substances have the ability to accumulate in the body.

• Level of Toxicity: The higher the level of toxicity, the wider the distribution throughout the body.

48. What do Fluorine, Calcium, and Phosphorus Have an Affinity For?

• Forming calcium fluorophosphate, which accumulates in teeth and bones: These elements have an affinity for calcium, forming salts that accumulate in teeth and bones.

49. Where is Lead Distributed?

• Acute: Liver, kidneys.

• Chronic: Keratinized cells.

50. Where is Lead Primarily Retained?

• Blood Cells: Lead has an affinity for red blood cells, so it is primarily retained there.

51. Where are Heavy Metals Primarily Retained?

• Liver: The liver is the main organ for metabolizing and eliminating toxins, so heavy metals accumulate there.

52. What is Phase 1 Metabolism?

• Phase 1 is an oxidation-reduction reaction: Makes the toxic substance more polar, making it easier to eliminate.

• Oxidation: Converting functional groups, for example, nitrite to nitrate, alcohol to CO2 and H2O, and side chains in hydrocarbons are more easily oxidized.

• Reduction: Converting functional groups, for example, chloral hydrate, nitrite to amines.

53. What Enzymes Participate in Phase 1 Metabolism?

• Cytochrome P450: A key enzyme in drug and toxin metabolism.

• Monooxygenase: Enzymes that catalyze oxidation reactions.

• ADH (Alcohol Dehydrogenase): An enzyme that metabolizes alcohol.

• ALDH (Aldehyde Dehydrogenase): An enzyme that metabolizes aldehydes.

54. What is the Purpose of Conjugation Reactions?

• Increased polarity, reduced toxicity, and easier elimination: Conjugation with endogenous molecules forms more polar derivatives that are less toxic and easier to eliminate.

55. What is the Energy Requirement of Conjugation Reactions?

• Requires energy: Conjugation reactions require energy to occur.

56. Is it Necessary to Activate the Conjugating Agent or the Toxic Substance Before Conjugation?

• Yes: Activation of one or both participating molecules is required for the reaction to occur.

57. What Substances Participate in Conjugation Reactions?

• Sulfate: Sulfate groups conjugate with toxic substances to form less toxic products.

• Glucuronic: Glucuronic groups conjugate with toxic substances to form more polar products, making them easier to eliminate.

• Glutathione: Glutathione groups conjugate with electrophilic toxic substances.

• Amino Acids: Amino acids can conjugate with toxic substances, such as glycine.

• Thiol Groups: Thiol groups conjugate with toxic substances to form less toxic products.

58. What Substance Provides the Sulfate Group for Conjugation?

• PAPS (Phosphoadenosine Phosphosulfate): Provides the sulfate group for the conjugation reaction.

59. What is the Mechanism of Glucuronic Conjugation?

• Aldehyde group of glucuronic: Converts to a semi-acetal OH, conjugating with substances having an OH group or forming an ester with acids.

60. What Substances does Glutathione Conjugate with?

• Electrophilic substances: Examples include aromatic hydrocarbons, halogenated derivatives of aromatic hydrocarbons, epoxides, etc.

61. Which Amino Acid is Most Frequently Involved in Conjugation?

• Glycine: Glycine is the most frequently conjugated amino acid.

62. What are the Mechanisms of Excretion through the Kidneys?

• Filtration: Toxic substances are filtered through the glomeruli, primarily through passive diffusion.

• Tubular Secretion: Toxic substances are secreted in the renal tubules, both passively and actively.

• Reabsorption: Toxic substances are reabsorbed in the renal tubules, mainly through passive diffusion.

63. What are the Requirements for Substances to be Filtered by the Glomerulus?

• < 100A: Size smaller than 100 angstroms.

• Water-soluble: Easily dissolves in water.

• Free Form: Not bound to plasma proteins.

64. Where does Reabsorption Typically Occur?

• Proximal and Distal Tubules: The proximal tubule is more commonly affected by toxic substances.

65. What are the Characteristics of Substances Excreted through the Liver and Bile?

• Typically oil-soluble: Oil-soluble toxic substances are easily excreted in bile.

66. What Drugs Undergo Enterohepatic Circulation?

• Morphine, digitalis cardiac glycosides: These drugs are excreted in bile, then reabsorbed in the intestines, forming an enterohepatic circulation.

67. What Factors Influence Excretion through the Respiratory System?

• Pulmonary Blood Flow: Higher pulmonary blood flow helps faster excretion of toxic substances through the lungs.

• Respiratory Rate: Faster breathing helps faster excretion of toxic substances through the lungs.

• Solubility of the Drug in Blood: Toxic substances that are more soluble in blood are excreted faster through the lungs.

68. What Gases are Excreted through the Lungs?

• CO2, H2S, HCN, alcohol, inhalational anesthetics: These substances can be excreted through the lungs.

69. What are Other Routes of Excretion?

• Milk, sweat, saliva, placenta, hair, nails: Some toxic substances can be excreted through these routes.

70. What are the Characteristics of Substances Excreted in Milk?

• Can be both oil-soluble and water-soluble: Toxic substances can be excreted in milk, posing a risk to breastfeeding infants.

71. Toxic Substances Entering the Body Typically Act Directly on Cells and Disrupt Their Function?

• True: Toxic substances disrupt the normal functioning of cells.

72. Do All Toxic Substances, Regardless of Entry Route, Distribute Throughout the Body After a Short Time?

• True: Toxic substances distribute throughout the body after a short time, but depending on the nature of the toxic substance, the site of contact, and duration of exposure, the effects may vary.

73. What are the Systemic Effects on Respiration?

• Tissue hypoxia: Toxic substances affect gas exchange, leading to tissue hypoxia.

• Respiratory depression: Toxic substances suppress the respiratory center, causing suffocation.

• Pulmonary edema: Toxic substances cause pulmonary edema, hindering gas exchange.

• Fibrosis: Toxic substances damage lung tissue, leading to fibrosis.

• Lung cancer: Toxic substances can cause lung cancer.

74. Do Most Toxic Substances Damage the Liver?

• True: The liver is the primary metabolic organ, so it is susceptible to damage from toxic substances.

75. What Can the Effects on Blood Include?

• Changes in plasma: Alterations in plasma composition.

• Changes in blood cells: Alterations in the number and function of blood cells.

• Appearance of new components: Some toxic substances can create toxic byproducts.

76. What are the Effects on Red Blood Cells?

• Increase: In cases of plasma loss, pulmonary edema.

• Decrease: In cases of benzene exposure, X-rays, etc.

77. What are the Effects on White Blood Cells?

• Decrease: In cases of benzene exposure.

• Increase: In cases of heavy metal exposure.

78. What are the Effects on Platelets?

• Decrease: In cases of benzene exposure.

79. What New Components Can Appear in the Blood?

• Coproporphyrin: In lead poisoning.

• Hematoporphyrin: In strong acid poisoning.

80. What is the Sequence for Managing Poisoning?

• Symptomatic treatment: Addressing the acute symptoms of poisoning.

• Elimination of the toxic substance: Removing the toxic substance from the body using appropriate methods.

• Reducing Toxicity: Using antidotes and supportive measures to reduce the toxicity of the substance.

81. What Organs Are Targeted for Direct Elimination of Toxic Substances?

• Skin, mucous membranes, digestive system: Direct elimination of toxic substances by washing the skin, mucous membranes, gastric lavage, etc.

82. When is Direct Elimination of Toxic Substances Most Effective?

• Within 6 hours: Direct elimination of toxic substances within 6 hours of exposure is more effective.

83. What is the First Step in Eliminating Toxic Substances from the Digestive System?

• Inducing vomiting: Inducing vomiting to remove the toxic substance from the stomach.

84. What are the Cases Where Vomiting Should Not be Induced?

• More than 4 hours: Inducing vomiting after 4 hours is ineffective.

• Coma, seizures: Inducing vomiting can be dangerous for the patient.

• Poisoning with strong acids, bases, or corrosive chemicals: Inducing vomiting can cause esophageal burns.

• Gasoline, volatile substances: Inducing vomiting can lead to pulmonary edema.

85. What Medications are Used for Gastric Lavage?

• KMnO4 or NaHCO3: Gastric lavage with KMnO4 or NaHCO3 solution (except in cases of acid poisoning, as it can produce CO2 and rupture the stomach).

86. What are the Cases Where Gastric Lavage Should Not be Performed?

• Esophageal burns caused by strong acids or alkalis: Gastric lavage can worsen burns.

• Strychnine: Causes severe seizures; gastric lavage can be dangerous.

• Oily substances: Gastric lavage is ineffective.

• Deep coma: Gastric lavage can be dangerous for the patient.

87. What is the Best Time Frame for Gastric Lavage?

• 3-8 hours: Gastric lavage within 3-8 hours of exposure is more effective.

88. What Amount of Lavage Fluid Should be Retained?

• 250-300 ml of initial fluid: Retain the initial fluid to identify the toxic substance.

89. What Medication is Used for Purgation?

• Sodium sulfate or magnesium sulfate: Using laxatives to eliminate toxic substances from the intestines.

90. What are the Cases Where Purgation Should Not be Performed?

• Poisoning with oily substances, organophosphates, and DDT: Purgation is ineffective.

91. What is the Purpose of Purgation?

• Increase intestinal motility: Helps to expel the toxic substance from the intestines.

• Reduce absorption of the toxic substance: Limits the absorption of the toxic substance into the bloodstream.

• Increase excretion: Promotes excretion of the toxic substance through feces.

• Reduce constipation: Due to the use of activated charcoal.

92. What is Used for Enema?

• 0.9% NaCl: Use of 0.9% NaCl solution for enema.

93. What Does Indirect Elimination of Toxic Substances Include?

• Respiratory system, kidneys, hemodialysis, blood transfusion: Methods of indirectly eliminating toxic substances through excretory organs.

94. What are the Ways to Increase Elimination through the Kidneys?

• Increase excretion: Fluid infusion, changing the pH of urine, hemodialysis.

95. What are the Characteristics of Peritoneal Dialysis and Blood Transfusion?

• Peritoneal dialysis: Similar to hemodialysis but less expensive.

• Blood transfusion: Removing a portion of toxic blood and replacing it with glucose and NaCl for compensation.

96. What Substances are Used to Absorb Toxic Substances?

• Activated charcoal: Most commonly used.

• Egg white: Absorbs some toxic substances, but less effectively than activated charcoal.

• Milk: Absorbs some toxic substances, but less effectively than activated charcoal.

• Kaolin: Absorbs some toxic substances, but less effectively than activated charcoal.

97. When are Absorbent Substances Used in Relation to Vomiting and Gastric Lavage?

• After: Absorbent substances are used after vomiting and gastric lavage to absorb any remaining toxic substances in the stomach and intestines.

• When the patient stops vomiting: If the patient stops vomiting, activated charcoal can be administered.

98. How are Specific Antidotes Used in Relation to Vomiting and Gastric Lavage?

• Before, during, and after: Specific antidotes are used before, during, and after vomiting and gastric lavage.

99. What Should Be Used to Form a Precipitate in Heavy Metal or Alkaloid Poisoning?

• Tannin: Tannin can precipitate heavy metals and alkaloids, reducing absorption and promoting excretion.

100. What are Antidotes?

• BAL (Dimecarprol): Antidote for heavy metals such as arsenic, mercury, and lead.

• DMSA (2,3 dimercaptosuccinic acid, succimer): Antidote for lead poisoning.

• EDTA: A metal-chelating agent, antidote for heavy metals such as lead, cadmium, and mercury.

101. What is a Universal Antidote?

• FeSO4/water and Na2SO3, MgO/water: Used as antidotes in cases of poisoning with various toxic substances.

102. In What Cases Should Artificial Respiration Not be Performed?

• Poisoning with bromine, chlorine, phosgene, SO2: Artificial respiration can worsen poisoning.

Note: This is a comprehensive article, so it may not be entirely complete or accurate. Consulting specialized resources is recommended for further understanding of the topic of toxic substances.