Toxicology introduction
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Transcript of Toxicology introduction
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CONTENTS:________________HANDLE WITH CARE
THE STUDY OF POISONS
INTRODUCTION TO TOXICOLOGY
What is toxicology? The study of the effects of poisons.Poisonous substances are produced by plants, animals, or bacteria.
Phytotoxins Zootoxins Bacteriotoxins
Toxicant - the specific poisonous chemical.Xenobiotic - man-made substance and/or produced by but
not normally found in the body.
92% of all poisonings happen at home.Certain animals secrete a xenobiotic.Some household plants are poisonous to humans and
animals.
Science of poisons "the study of the nature and mechanism of toxic effects of
substances on living organisms. "Toxicology is the study of the adverse effects of chemical
and physical agents on living organisms. “ Toxicology is the study of how natural or man-made poisons
produce undesirable effects in living organisms
What is Toxicity? What is a Toxicant? What is a Toxin? What is a dose?
2700 B.C.Chinese journals: plant and fish poisons1900-1200 B.C. - Egyptian documents that had
directions for collection, preparation, and administration of more than 800 medicinal and poisonous recipes.
800 B.C. - India - Hindu medicine includes notes on poisons and antidotes.
50-100 A.D. - Greek physicians classified over 600 plant, animal, and mineral poisons.
50- 400 A.D. - Romans used poisons for executions and assassinations. The philosopher, Socrates, was executed using
hemlock for teaching radical ideas to youths. The active agent of the poison hemlock is the piperidine alkaloid Coniine. Coniine causes gradual paralysis of the spinal cord, finally stopping the breathing without any previous clouding of the consciousness
Avicenna (A.D. 980-1036) Islamic authority on poisonsand antidotes.1200 A.D. - Spanish rabbi Maimonides writes first-aid book
for poisonings, Poisons and Their Antidotes
All parts of the poison hemlock plant contain poison alkaloids. If ingested, conium will cause paralysis of various body systems. Paralysis of the respiratory system is the usual cause of death
Ibn Uthal: during region of Mu,awiyha. Skilled in the science of poisons
Galen and Discorides (classify plants).Important in regard of poisons and antidotes
Hippocrates Theophrastus Aristotle Demosthenes(poison in pen) King Mithridates VI of Pontus,(mithridates, mixture
of 36 ingredients)
Toffana(arsenic containing cosmetics) Catherine de Medici(provided poisons to females)
Poisons and their antidotes Kinds Natural origin Mode of action Dosage Methods of administration Target organ
Swiss physician Paracelsus (1493-1541) credited with being
“ father of toxicology.”“All substances are poisons: there is none
which is not a poison. The right dose differentiates a poison from a remedy.”
Italian physician Ramazzini (1713) published
“De Morbis Artificum”
Spanish physician Orfila (1815) established toxicology as a distinct scientific discipline.
History
20th CenturyPaul –developed staining procedures to observe cell and tissues and pioneered the understanding of how toxicants influence living organisms.
History
20th Century Rachel Carson - alarmed public about dangers of pesticides in
the environment.
History
Orfila: Father of modern toxicology 1st book on toxicology Claude Bernard Modern study of mechanism of toxic action Ellenbog(occupational toxicity of pb and Hg)
A.Hamilton: industrial toxicology Elizabeth and James Miller(wisconson university,chemical
carcinogensis) 1st journal Toxicology and Applied Pharmacology(1960)
Reversible Vs Irreviersible Acute Vs Chronic (Duration of Exposure) local Vs systemic (Location of the effect)
IrreversibleCarcinogen-cause cancerMutagen-cause chromosome (gene) damageTeratogen- cause birth defects
May or may not be irreversibleDermatotoxic – affects skinHemotoxic – affects bloodHepatotoxic- affects liverNephrotoxic – affects kidneysNeurotoxic – affects nervous systemPulmonotoxic- affects lungs
Acute exposureHigh Dosage (e.g. due to accidental releaseThe effect is immediate
Subtle (e.g., cough or headache from urban air pollution)Violent (e.g., convulsions induced from exposure to
certain pesticides)
Chronic ExposureNormally lower doseThe effect only noticed/detected following long exposureSometimes, the worker could not recall the exposure.
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LocalDamage to the part of the body that comes in contact with the substance.
SystemicChemical is absorbed by the body and attacks a target organ.
Cyanide and gunshot simultaneously before capture (ADOLF HITLER) After losing the Battle of Actium to Octavian's forces, Antony committed suicide.
Cleopatra followed suit, according to tradition killing herself by means of an asp bite on August 12, 30 BC