1 Rescue me, LORD, from evildoers;
protect me from the violent,
2 who devise evil plans in their hearts
and stir up war every day.
3 They make their tongues as sharp as a serpent’s;
the poison of vipers is on their lips
-Psalms 140:1-3 (NIV)
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| Photo Credit: http://www.momeomagazine.com/tag/training-people-how-to-treat-you/ |
You might wonder why I started my blog with verses from the Bible.
(again, this is not a Bible study Guys :)) A poisonous or toxic thing for me,
is not simply a substance that may harm someone or something but a
tuckless or negligible word being held-out by a person that has negative impact on others.(perhaps, a TOXIC FRIEND. Haha) Death and life are in the power of the tongue so we
should be careful in using this muscular
hydrostat on the floors of the mouths. :)
The word "Toxic"
as defined in Merriam-Webster dictionary, is containing
or being a poisonous material especially when capable of causing death or
serious debilitation but for us Medical students, specifically Medical
Technology Students here in Angeles University Foundation, being toxic means,
being in a state of stress and exhaustion. Why am I saying this by the way?
Most of us, are familiar with this word, but does not have a better
understanding of it. As we go on, you will learn more about it.
Peter Mere Latham (1789-1875) is credited with the
statement "Poisons and Medicines are oftentimes the same substance given
with different intents". While this remark was penned in a bygone error,
it is probably truer today that it was then. Sometimes, the thing that is
intended to benefit us, may harm us when we improperly used or utilized
it.
What is Toxicology? Toxicology
is the study of the adverse effects of chemicals on living organisms. It is the
study of symptoms, mechanisms, treatments and detection of poisoning,
especially the poisoning of people. It may also be defined as a science
that combines biology and chemistry to study poisons and their effect on
biological systems. Toxicology addresses a variety of questions. For example,
in agriculture, toxicology determines the possible health effects from exposure
to pesticides or herbicides, or the effect of animal feed additives, such as
growth factors, on people. Toxicology is also used in laboratory experiments on
animals to establish dose-response
relationships. Toxicology also deals with the way chemicals and waste products
affect the health of an individual.
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| Photo Credit: http://www.gaia-health.com/articles101/000142-by-law-chemicals-dont-have-to-be-listed-if-hurts-profits.shtml |
Sub-Disciplines of Toxicology |
Description
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Environmental Toxicology
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Concerned with the study of chemicals
that contaminate food, water, soil, or the atmosphere. It also deals
with
toxic substances that enter bodies of waters such as lakes,
streams, rivers, and oceans
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Occupational (Industrial) Toxicology
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Concerned with health effects from exposure to chemicals
in the workplace. This field grew out
of a need to protect workers from toxic substances and to
make their
work environment
safe
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Regulatory Toxicology
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Gathers and evaluates existing
toxicological
information to establish
concentration-based standards of “safe” exposure. The standard is the level
of a chemical that a person can be exposed to without any harmful health
effects
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Food Toxicology
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involved in delivering a safe and edible supply
of food to the consumer
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Clinical Toxicology
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Concerned with diseases and
illnesses associated with short term or long term exposure to toxic chemicals
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Descriptive Toxicology
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Concerned with gathering toxicological
Information from animal experimentation. These types of
experiments are used to establish how much of a chemical would cause illness
or death.
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Forensic Toxicology
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Used to help establish cause and effect
relationships between exposure to a drug or chemical and the toxic or lethal
effects that result from that exposure.
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Analytical toxicology
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Identifies the toxicant through analysis of
body fluids (e.g. urine, blood, bile, oral fluid,
vitreous humor or cerebrospinal fluid) and tissues (brain cortex, liver,
heart, kidney, fat tissues), stomach content, and/or drug paraphernalia. Hair
is mostly used to detect long-term exposure to drugs of abuse.
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Mechanistic Toxicology
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Makes observations on how toxic
substances cause their effects. The effects of exposure can depend on a number
of factors, including the size of the molecule, the specific tissue type or
cellular components affected, whether the substance is easily dissolved in
water or fatty tissues.
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| Photo Credit: http://www.chicagonow.com/so-you-have-a-girlfriend/2012/03/the-toxic-relationship-2/ |
Classification of Toxic Agents:
Toxic substances are
classified into the following:
A. Heavy Metals
Metals differ from other
toxic substances in that they are neither created nor destroyed by humans.
Their use by humans plays an important role in determining their potential for
health effects. Their effect on health could occur through at least two mechanisms:
first, by increasing the presence of heavy metals in air, water, soil, and
food, and second, by changing the structure of the chemical. For example, chromium
III can be converted to or from chromium VI, the more toxic form of the metal.
B. Solvents and Vapors
Nearly everyone is
exposed to solvents. Occupational exposures can range from the use of
“white-out” by administrative personnel, to the use of chemicals by technicians
in a nail salon. When a solvent evaporates, the vapors may also pose a threat
to the exposed population.
C. Radiation and Radioactive Materials
Radiation is the release
and propagation of energy in space or through a material medium in the form of
waves, the transfer of heat or light by waves of energy, or the stream of particles
from a nuclear reactor.
D.Dioxin/FuransDioxin, (or TCDD)
It was originally discovered as a contaminant in the herbicide Agent Orange. Dioxin is also a by-product of chlorine processing in paper producing industries.E. Pesticides
The EPA defines
pesticide as any substance or mixture of substances intended to prevent,
destroy, repel, or mitigate any pest. Pesticides may also be described as any
physical, chemical, or biological agent that will kill an undesirable plant or
animal pest.
F. Microbial toxins
Bacteria, fungi and
algae are the microorganisms typically associated with microbial toxin production. Cholera toxin
produced by Vibrio cholerae is the virulence factor responsible for the massive
secretory diarrhea seen in Asiatic cholera (5 million cases each year).
G. Mushroom toxins
Several mushroom species
(e.g. Amanita phalloides, A. virosa), produce a family of cyclic octapeptides
called amanitins. Symptoms of intoxication appear at the end of a latent period
of 6-48 hours during which the patient shows no symptoms.
H. Plant Toxins
Different portions of a
plant may contain different concentrations of chemicals. Some chemicals made by
plants can be lethal. For example, taxol, used in chemotherapy to kill cancer
cells, is produced by a species of the yew plant.
I. Animal Toxins
These toxins can result
from venomous or poisonous animal releases.
Subcategories of Toxic Substance Classifications
All of these substances
may also be further classified according to their:
- Effect on target organs (liver, kidney, hematopoietic system),
- Use (pesticide, solvent, food additive),
- Source of the agent (animal and plant toxins),
- Effects (cancer mutation, liver injury),
- Physical state (gas, dust, liquid),
- Labeling requirements (explosive, flammable, oxidizer),
- Chemistry (aromatic amine, halogenated hydrocarbon), or
- Poisoning potential (extremely toxic, very toxic, slightly toxic)
References:
Poisoning and Toxicology Compendium with Symptoms Index by Jerrold B. Leikin (1998) Clinical Chemistry: Techniques, Principles, Correlations 6th Ed. by Michael L. Bishop et al. (2010)
