FIN

• Insecticides


  • Paraquat
  • Phenoxyacetic acid
  • Glyphosate
  • Dichlorodiphenyltrichloroethane (DDT)

  
• Pesticides


  • Any substance or mixture of substances intended for preventing, destroying, repelling, or mitigating pests
  • Can be classified as insecticides, herbicides, fungicides, rodenticides, acaricides, molluscicides, miticides, larvicides, and pediculicides
• Routes of pesticide exposure


  • Accidental/suicidal poisoning
  • Occupational exposure (manufacturing, mixing/loading application, harvesting & handling crops)
  • Bystander exposure from spraying operations
  • General public who consumes food items containing pesticide residues
• Acetylcholinesterase inhibitors


  Most commonly used insecticides, especially in farm areas, including organophosphates and carbamates
• Mechanism of action of acetylcholinesterase inhibitors


  Binds to acetylcholinesterase, preventing degradation of acetylcholine, leading to excessive accumulation in the synapse and excessive parasympathetic stimulation
• Chlorinated hydrocarbons (DDT and analogs)


  Organochlorine pesticides that have largely been abandoned due to severe environmental damage
• Pyrethrins and pyrethroids


  • Most commonly used pesticides in the home, derived from Chrysanthemum flower and synthetic derivatives, respectively
  • Toxicity is usually associated with hypersensitivity reactions and direct irritant effects
• Nicotine


  Has the same effect on nicotinic cholinoceptors in insects as in mammals (excitation followed by paralysis)
• Rotenone


  Plant alkaloid pesticide that causes gastrointestinal distress when ingested and conjunctivitis and dermatitis after direct contact
• Other pesticide classes


  • Chlorophenoxy compounds (2,4-D, 2,4,5-T)
  • Bipyridyl compounds (Paraquat, Diquat)
  • Chloroacetanilide compounds (Alachor, Acetochlor, Metolachlor, Butachlor)
  • Triazines (Atrazine, Simazine, Propazine)
  • Phosphonomethyl amino acids (Glyphosate, Glufosinate)

  
• Antidotes for heavy metal poisoning

  • Prussian blue (for thallium and cesium poisoning)
  • Sodium polystyrene (for lithium poisoning)
  • Activated charcoal (for most drug poisonings)
• Heavy metals of concern

  Arsenic, mercury, and lead are the top 3 pollutants of concern based on their toxicity and levels of human exposure
• Heavy metal poisoning


  • Metals are inhaled primarily as dust and fumes, and metal poisoning can also result from exposure to vapors
  • GIT absorption varies with specific chemical form of metal and nutritional status of the host
  • Some organs will store/sequester metals in relatively high concentrations for years (Bone, Liver, Kidneys)
  • Some metals, such as copper and selenium, are essential to normal metabolic function as trace elements but are toxic at high levels of exposure, while others, such as lead and mercury, are capable of exerting effects at any level of exposure
• Arsenic


  The "poison of kings and king of poisons", primary exposure is through drinking water, can exert effects through multiple mechanisms including activating degenerative oxygen species and generating reactive oxygen species

  
• Cadmium


  Primary source of exposure is through food, mechanism of toxicity not fully understood but may involve competing with zinc and calcium
• Protein


  Lose structure (inactivation)
• ACUTE symptoms of cadmium toxicity

  • Hemorrhagic gastritis
  • Fluid loss
  • Hypotension
  • Acute Tubular Necrosis
• CHRONIC symptoms of cadmium toxicity

  • Milk and roses complexion
  • Cancer (Skin, liver, lung, bladder, & kidney)
  • Gangrene (Black foot disease)
  • Mee's line

  
• Diagnosis of cadmium toxicity

  Abdominal Xray
• Acute treatment for cadmium toxicity

  • Ipecac (not used anymore)
  • Gastric lavage
  • Activated charcoal + Cathartics
• Chronic treatment for cadmium toxicity

  • Dimercaprol
  • Succimer (Alt.)
• The primary source of exposure of the general population to cadmium is through food
• Sources of cadmium exposure include metal-plating, smelting, battery, and plastics
• Itai-itai disease ("Ouch-ouch disease") is caused by cadmium toxicity
• Mechanism of cadmium toxicity

  Not fully understood (Competes with Zn, Ca)

  Postulated that Cadmium competes with calcium in bone deposition
• ACUTE symptoms of cadmium toxicity

  • Acute toxicity is due to local irritation along the absorption route
• CHRONIC symptoms of cadmium toxicity

  • Painful bone fractures
  • Osteomalacia
• Diagnosis of cadmium toxicity

  History/PE+Elevated Cd blood levels
• There is no effective treatment for cadmium poisoning
• Transition metals can cause toxicity in excess
• Copper toxicity is seen in Wilson's disease, and copper deficiency is seen in Menkes syndrome
• Heavy metals have a U-shaped dose response curve

  
• Heavy metals are chelators except for lead
• Lead accumulates in the long bones (diaphysis) and can be seen as a radioluscent area on X-ray
• Heavy metals are both toxins and toxicants
• Heavy metals cause ROS production and DNA damage leading to cancer and cell lysis
• Heavy metals can cause white transverse lines on the nails and bone fractures
• Heavy metals can cause denaturation of proteins
• For most of the 20th century, the major source of lead exposure were lead-containing house paints and gasoline
• Lead is not degradable and remains in dust, soil, and paint of older homes. Young children are exposed by ingesting lead-containing materials