W. Tassaneeyakul W. Tassaneeyakul 1 Principles of Principles of Toxicology : Toxicology : The Study of Poisons The Study of Poisons Wongwiwat Tassaneeyakul Wongwiwat Tassaneeyakul Department of Toxicology Department of Toxicology Khon Kaen University Khon Kaen University [email protected][email protected]
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W. Tassaneeyakul 1 Principles of Toxicology : The Study of Poisons Wongwiwat Tassaneeyakul Department of Toxicology Khon Kaen University [email protected].
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W. TassaneeyakulW. Tassaneeyakul 11
Principles of Principles of Toxicology :Toxicology :
A villager uses a dip net to remove dead fish from the Bang Pakong river. The fish, bred in floating baskets, died from pollution in the river. _ TAWATCHAI KEMGUMNERD
TOXICOLOGYTOXICOLOGY : The study of the : The study of the adverse effectsadverse effects of a of a toxicanttoxicant on on living organismsliving organisms..
Toxicology related closely to Pharmacology, Biochemistry, Molecular biology, Chemistry, Epidemiology, Pathology, Genetics, Public Health, Medicine, etc.
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HazardHazard – physical situation that can – physical situation that can damage:damage:
– people people – plant plant – EnvironmentEnvironment
RiskRisk – likelihood of hazard occurring – likelihood of hazard occurring
RiskRisk = = hazardhazard * probability * * probability * consequenceconsequence
W. TassaneeyakulW. Tassaneeyakul 1212Source: Muckter, 2003
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1. Toxicant/ Toxin/ Poison/ Hazard any agent capable of producing a
deleterious response in a biological system
2. Adverse/Toxic effects any unwanted change from an organism’s
normal state dependent upon the concentration of active
compound at the target site (receptor)for a sufficient time.
3. Living organism cellular target sites/ storage depots and
enzymes
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COMMON TOXICOLOGY QUESTIONSCOMMON TOXICOLOGY QUESTIONS
1. What is a poison?
2. Where dose it come from? (exposure Q)
3. How does it get into living organism?
(exposure Q)
4. What does it do to living organism?
(mechanism Q)
5. How can we treat/prevent this toxicity?
(clinical Q)
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Routes of Entry:Routes of Entry:
OralOral == Ingestion by mouthIngestion by mouth
DermalDermal == Skin exposureSkin exposure
InhalationInhalation == Absorbed by lungsAbsorbed by lungs
OcularOcular = = Eye exposureEye exposure
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Why human have to concern with other species toxicology and/or environmental health?
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Classification of Toxic AgentsClassification of Toxic Agents
All All substancessubstances are poisons; are poisons; there isthere is nonenone that is not a that is not a poison. The rightpoison. The right dose dose differentiates a poison and a differentiates a poison and a remedy.remedy.
Paracelsus Paracelsus
(1493- 1541)(1493- 1541)
THE DOSE MAKES THE THE DOSE MAKES THE POISONPOISON
Chemical antagonismChemical antagonismDispositional antagonismDispositional antagonismFunctional antagonismFunctional antagonismPharmacological antagonismPharmacological antagonism
Toxicity Interactions
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Synergist / Synergist / SynergismSynergism::
Synergism is increased activity (toxicity) resulting from the effect of one chemical on another.
LD50 DDT = 250 mg/kg
LD50 synergist = 1,000 mg/kg
LD50 DDT + synergist = 50 mg/kg
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Source: van den Brandt et al. 2002
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W. TassaneeyakulW. Tassaneeyakul 4545Source: “A Primer on Toxics”
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ConclusionConclusion
What is toxicology ?What is toxicology ? Toxicity, poison, hazard, risk ?Toxicity, poison, hazard, risk ? Why dose-response study is so important in Why dose-response study is so important in
toxicology?toxicology? How can we classify type of toxicity ?How can we classify type of toxicity ? Why people response differently to toxicant ? Why people response differently to toxicant ?