Toxicology introduction

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HAZARDOUS WASTESTART DATE:______________

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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