Clinical Chemistry Blog Notes 4F: Toxicology

"All things are poison and nothing is without poison; only the dose makes a thing not a poison."

"The dose makes the poison"

.....Paracelsus.....

All chemicals could be toxic that could be easily acquired because they are widely available but the degree of side effect that a chemical can affect humans or any other living being depends on the dose or the degree of exposure.

Every time we heard toxic, normally comes in our mind something that was harmful and poisonous to anyone’s health that may cause disease, tissue damage, genetic alterations, cancer, and in severe point can lead to death. To further understand, let we first define toxicology which covered the broad insights about toxic substances, agents and its effect.

Toxicology traditionally defined as the branch of science of poisons. As our understanding of how various agents can cause harm to humans and other organisms, a more descriptive definition of toxicology is the study of the adverse effects of chemicals or physical agents on living organisms. It is the study of symptoms, mechanisms, treatments and detection of poisoning, especially the poisoning of people.

Toxicology terms:

§ Toxicity

Ø The degree to which a substance can harm human or animal.

Ø It may be:

o Acute- Single/short term exposure.

o Sub-chronic- > one year but < the lifetime of the exposed organism.

o Chronic- Mixture substances cause harmful effect over an extended period, upon repeated/continuous exposure.

§ Toxicant

Ø Man made substance that cause adverse biological effect

§ Toxin

Ø poison produced naturally by an organism (plants, animals, insects)

3 phases of toxicology

1. Exposure- toxins can enter the body via several routes;

§ Ingestion (Gastro intestinal tract)

§ Inhalation (lungs)

§ Transdermal absorption (skin)

§ Rectal (Suppository)

§ Injection (bite, puncture, or cut)

2. Toxicokinetics- concerned with the concentration of the chemical once it enter the body and what happens to it in the body

3. Toxicodynamics-denote the injurious effects of these substances on body functions

Includes:

§ toxic effect

§ mechanism of toxic effects

§ dose effect relationship

§ interactions of toxins

Sub-specialties of Toxicology

· Mechanistic toxicology	Elucidates the cellular and biochemical effects of toxins. It provide a basis for rational therapy design and the development of test to assess the degree of exposure of poisoned individuals
· Descriptive toxicology	Deals with collecting toxicological information from animal experimentation to predict what level exposure will cause harm in humans
· Forensic toxicology	Primarily concerned with the medicolegal aspects of toxin exposure to generate evidence in legal situations, including the cause of death
· Clinical toxicology	Deals with the diagnosis of diseases and illnesses associated with exposure to toxic chemicals; and also therapeutic intervention
· Occupational (Industrial) Toxicology	concerned with health effects from exposure to chemicals in the work environment
· Regulatory toxicology	Perform risk assessment by gathering and evaluation of existing informational data from descriptive and mechanistic toxicology