Clinical Chemistry Blog Notes 22D

TOXICOLOGY?

photo credit : http://www.scienceclarified.com/Ph-Py/Poisons-and-Toxins.html#b

Toxicology is not only the study of poisons or something dangerous to our health; it is the study of substances introduced exogenously into the body and also the adverse effects of chemicals on living organisms. And all the substances are poisons; the only difference is the amount of intake or the dosage.

Terms to remember in Toxicology

Toxicants	-Substance that produce adverse biological effects of any nature -may be chemical or physical in nature -may be acute or chronic Ex. Lead, Mercury
Toxins	-Specific proteins produce by living organisms (mushroom toxin or tetanus toxin) -Most exhibit immediate effects
Poisons	-toxicants that cause immediate or illness when experienced in very small amounts.
Organic toxins	-Substances that were originally derived from living organisms -contain carbon and often are large mol. Can be synthesized as well as be obtained from natural sources.
Inorganic toxins	-chemicals not derived from the living organisms (minerals) -generally small mol. consisting of only few atoms (such as nitrogen dioxide)

Branches of toxicology

Clinical Toxicology	-it deals with emergencies such as overdoses, poisonings and/or attempted suicides. -deals with compound ID and quantification -signs and symptoms management -emergency care -poison control
Forensic toxicology	-medical-legal aspects -ID and quantification of poisons -establish relationship between tissue residual level and probable cause of death.
Industrial toxicology	-estimation of worker safety based on 8hr work day, 40hr work week. -engineering of safety measures -air sampling, worker sampling.
Environmental toxicology	-effects of compounds on water, wildlife. -Movement of chemicals in the environment – soil, air, water. - Residual life of chemicals in the environment.
Biochemical & Molecular Toxicology	- Determining mode of action of chemicals at the molecular level. - Effect of chemicals on DNA, cancer genes….
Descriptive toxicology	-The study of the level of exposure that causes harm to humans using the results obtained from the experiment done in animals.

LD50 -the measure for expressing and comparing the toxicity of chemicals.
-dose that kills half (50%) of the animals tested (LD = "lethal dose")
-animals are usually rats or mice, although rabbits, guinea pigs, hamsters

Acute toxicity- short term effect due to exposure to a toxic chemical, that results in obvious health effects and even death.

Chronic toxicity- long term exposure to a toxic chemical, or exposed to the substance continuously or repeatedly.

Exposure - concentration of a chemical in the environment or the accumulated dose that an organism encounters.

Chemical hazards in the workplace and in the environment

Category	Examples
Inorganics	asbestos, carbon monoxide, hydrogen sulphide
Phenols	phenol, pentachlorophenol
Metals, and metalloids	arsenic, cadmium, lead, mercury, nickel, tin, etc
Hydrocarbons - aliphatic	propane, butane, pentane, hexane
Hydrocarbons - aromatic	benzene, toluene, xylene, naphthalene
Aliphatic alcohols, ketones, ethers, aldehydes and acids	ethyl alcohol (ethanol), acetone, diethyl ether, formaldehyde, acetic acid
Chlorinated volatile organic compounds	perchlorethylene (tetrachloroethene), trichloroethylene (trichloroethene), vinyl chloride
Miscellaneous organic compounds	acrylonitrile, benzidine, aniline, di-isocyanates, organophosphates
Chlorinated non volatile organic compounds	chlorinated dioxins and dibenzofurans, polychlorinated biphenyls, pesticides such as chlordane and DDT