Toxicology: The Science of Poisons

Definition


Look around you. Everything in the environment is made of chemicals (natural and synthetic). Think of all the things that made your life easier and improved your lifestyle and how these things can be poisonous.


Basically toxicology is the science of poisons and its adverse effects to a living organism. Poisons are defined as any substance that causes harmful effects when administered, either by accident or intended.


Toxicology is considered as the oldest scientific discipline since the earliest humans classified which plants are safe to be eaten.

• Toxicant
• the specific poisonous chemical.

• Poisonous substances are produced by bacteria, animals and plants.

Bacteriotoxin

Zootoxin

Phytotoxin

Modes of Toxic Action

a. Biochemical and molecular toxicology - includes enzymes that metabolize xenobiotics.


b. Behavioral toxicology - effects of toxicants on human and animal behavior. This involves the preipheral and central nervous system and the endocrine system.


c. Nutritional toxicoloogy - effects of diet on the expression of toxicity and with the mechanisms of these effects.


d. Carcinogenesis - includes the chemical, biochemical and molecular events which leads to cancer.


e. Teratogenesis - includes the chemical, biochemical and molecular events which leads to deleterious effects on development.


f. Mutagenecity - concerned with toxic effects on the genetic material and the inheritance of these effects.


g. Organ toxicity - effects at the level of organ function (E.g neurotoxicity, hepatoxicity, nephrotoxicity, etc.)

Applied Toxicology

a. Clinical toxicology - diagnosis and treatment of human poisoning.


b. Veterinary toxicology - diagnosis and treatment of poisoning in animals and the possible transmission of toxins from animals to humans.


c. Environmental toxicology - concerned with the movement of toxicants and their metabolites and degradation products in the environment and in food chains.


d. Forensic toxicology - concerns in the medico-legal aspects, including detection of poisons in clinical samples.


e. Industrial toxicology - specific area of environmental toxicology that deals with the work environment and constitutes a significant part of industrial hygiene.

Uses of Toxicology

 

a. Agricultural chemicals - insecticides, herbicides, fungicides and rodenticides.


b.Clinical drugs - Toxic side effects of phramaceutical chemistry and phramacology.


c. Drugs of Abuse


d. Food additives - foods which are toxic or being tested for possible toxicity.


e. Industrial chemicals

Sources Toxic Compounds

1. Exposure Classes - include toxicants in food, air, water and soil.
2. Use Classes - Drugs of abuse, therapeutic drugs, agricultural chemicals, food additives and contaminants, metals, solvents, combustion products, cosmetics and toxins.

Routes of  Exposure 

 

• Ingestion (food and water)

• Absorption (Through skin)

• Injection (bite, puncture or cut)

• Inhalation (air)

DID YOU KNOW?

• 92% of all poisonings happen at home.
• The household products implicated in most poisonings are; cleaning solutions, fuels, medicines and other materials such as glue and cosmetics.
• Certain animals secrete a xenobiotic poison called venom, usually injected with a bite or sting and other animals harbor infectious bacteria.
• Some household plants are poisonous to humans and animals.
• CAUTION - lowest degree of relative toxicity
• WARNING- intermediate degree of relative toxicity
• DANGER- highest degree of relative toxicity

"All substances are poisons; there is none

that is not a poison. The right dose differentiates a poison and a remedy” -- Paracelsus (Father of Toxicology)

REFERENCES:


A textbook of modern toxicology Third edition Ernest Hodgson, PhD



http://ca-biomed.org/csbr/pdf/PoisonB.pdf


http://nrupentheking.blogspot.com/2011/03/dns-poisoning-tutorial-2-internet-dns.html 


http://criminaljustice.pppst.com/drugabuse.html


http://birthofanewearth.blogspot.com/2012/05/prenatal-pesticide-exposure-may-harm.html


http://blog.martindale.com/prosecutors-attempt-to-stem-growing-epidemic-in-prescription-drug-abuse

Introduction to Endocrinology: A Woman's tale

Source

Have you ever experienced picking a fight with someone without a valid reason or getting angry just because your classmate is breathing? What about getting pissed by the wind blowing your hair or with the sound of the clock ticking and you are so irritated you want to shout and smash everything that is around you (I'm exaggerating don't smash anything, that wont do you any good and its costly) Or you can't figure out if you will go to the bathroom or you will not go to the bathroom. If you are a guy, then you must be in a really, really bad mood, maybe you are just tired and hungry, or maybe you have a problem you should consult a psychologist but most likely you're just hungry. But if you're a girl, welcome to womanhood. Warning: That happens once every month, so better prepare yourself. :))

People say that menstruation is one of the many physical signs that a girl is turning into a woman. Women have different ways in dealing with menstruation, some women can't wait to start their periods and get over with it while some may feel anxious or afraid. Most girls experience physical and emotional symptoms during, before or after their menstrual period which is now medically defined as PMS or Premenstrual Syndrome. PMS symptoms vary, it generally include muscle pain, breast tenderness, tension, diarrhea, a strong craving for sweets and of course the infamous irritability and mood swings. And what can boyfriends or husbands do but to blame the "Hormones". 

Hormones are chemicals or substances produced by the organs in the endocrine system to carry messages from the organs that produced them to the different cells in the body specifically the target cells, hence hormones are called the "chemical messengers in the body". Endocrinology is a branch of science which deals with the study of the endocrine system (which main function is to produce hormones), endocrine glands' function, structure and the diseases related to the endocrine system. 

The main hormones responsible for PMS are estrogen and progesterone. Estrogen and progesterone ( testosterone in males) in general are important in sexual functions, in producing the secondary sex characteristics of bone and muscle growth and maintenance, distribution of fat and body hair, breast development, etc.

This will only give you a hint of what Endocrinology is all about, since this is only an introduction.

Below is an illustration of the Endocrine system:

References:

Gerard J. Tortora and Bryan H. Derrickson 12^th Edition Principles of Anatomy and Physiology

Donald F. Calbreath Clinical Chemistry: A Fundamental Textbook

http://endo.endojournals.org/
http://www.bodylogicmd.com/for-women/pms-hormones