TOXICOLOGY PREFINAL

• Organ Specific Toxic Effects


  Toxic effects that pertain to specific organs and organ systems
• Organ systems affected by toxic effects


  • Blood and Cardiovascular/Cardiac
  • Dermal
  • Eye
  • Hepatic
  • Immune
  • Kidney
  • Nervous system
  • Reproductive
  • Respiratory
• Blood and Cardiovascular/Cardiac Toxicity


  • Xenobiotic acting directly on cells in circulating blood, bone marrow, and the heart
• Blood and Cardiovascular/Cardiac Toxicity

  • Hypoxia due to carbon monoxide binding of hemoglobin
  • Decrease in circulating leukocytes due to chloramphenicol damage
  • Leukemia due to benzene damage of bone marrow cells
  • Arteriosclerosis due to cholesterol accumulation
  • Death of normal cells in and around the heart due to cancer drugs
• Dermal Toxicity


  • Toxicant comes into direct contact with the skin or is distributed to it internally
• Dermal Toxicity


  • Dermal irritation from gasoline
  • Dermal corrosion from sodium hydroxide
  • Dermal itching, irritation, and rash from poison ivy
  • Skin cancer due to arsenic or UV light
• Eye Toxicity


  • Direct contact with or internal distribution to the eye
• Eye Toxicity


  • Corneal corrosion from acids and alkalis
  • Cataracts from corticosteroids
  • Optic nerve damage from methanol
• Hepatotoxicity


  • Toxicity to the liver, bile duct, and gall bladder
• Immunotoxicity


  • Toxicity of the immune system, including hypersensitivity, immunodeficiency, and uncontrolled proliferation
• Immunotoxicity


  • Contact dermatitis from poison ivy
  • Systemic lupus from hydrazine exposure
  • Immunosuppression by cocaine
  • Leukemia induced by benzene
• Nephrotoxicity


  • Toxicity to the kidneys, resulting in decreased ability to excrete wastes, maintain fluid/electrolyte balance, and synthesize hormones
• Neurotoxicity


  • Toxicant damage to cells of the central and peripheral nervous systems, including neuronopathies, axonopathies, demyelination, and interference with neurotransmission
• Reproductive Toxicity


  • Toxicant damage to the male or female reproductive system, causing effects like decreased libido, infertility, pregnancy issues, birth defects, and childhood cancer
• Respiratory Toxicity


  • Effects on the upper and lower respiratory system, including pulmonary irritation, asthma/bronchitis, emphysema, fibrotic lung disease, and lung cancer
• Epigenetics


  Studying how external or environmental factors can switch genes on and off and change the programming of cells, without changing the DNA sequence
• Toxicants are examples of factors that can alter genetic programming
• Current challenge in toxicology is to develop screening methods that would detect epigenetic alterations caused by toxicants
• Research is being done to assess epigenetic changes caused by toxicants, funded by the NIH National Institute of Environmental Health Sciences