What is toxicology?. toxic compounds physical agents.
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Transcript of What is toxicology?. toxic compounds physical agents.
What is toxicology?
toxic compounds
physical agents
toxicology …………
• Is the study of the harmful effects of chemicals and physical agents on living organisms
• Examines adverse effects ranging from acute to long-term
• Is used to assess the probability of hazards caused by adverse effects
• Is used to predict effects on individuals, populations and ecosystems
`
These adverse effects may occur in many forms, ranging from immediate death to subtle changes not realized until months or years later.
They may occur at various levels within the body, such as an organ, a type of cell, or a specific biochemical.
Sources of toxic compoundsSynthetic organic compound1. Air, water, and food pollutants
Air-CO, oxides of nitrogen, oxides of sulfur, hydrocarbons and particulatesWater-agricultural chemicals including pesticides, herbicides, fugicides, nematocides, rodenticides, fertilizer
Halogenated hydrocarbons- chloroform, dichloroethane, tetrachloride
Clorinated aromatics-PCB, TCDDDetergents-alkyl benzene sulfonates
2. Chemical additives in food
As preservatives-antibacterial, antifungal, or antioxidant
To change physical characteristics, taste, color, odor
.
3.Chemicals in work place Inorganics-metals and flurides, CO, etc. Organic compounds-aliphatic hydrocarbons (hexene)
aromatic hydrocarbons (eg. benzene, toluene)halogenated hydrocarbonsalcoholsestersorganometallicsamino compounds
4. Drugs of abuseCNS depressants-ethanol,secobarbitalCNS stimulants-cocaine, methamphatamine,
nicotine, caffeineOpioids-heroin, morphineHallucinogens-PCP, LSD,THC
5.Therapeutic drugs The danger to the individual depends on :
the nature of the toxic responsethe dose necessary to produce the toxic responsethe relationship between the therapeutic dose and
the toxic doseeg, anticancer drugs are carcinogens
Diethylstilbestrol (DES)Thalidomide
Chloroquinol-SMON-subacute myelo-optic neuropathy
Methyldopa, chloropromazine, methotrexateIn general, toxic side effects are not common and
may occur only in susceptible individuals or populations.
6. Pesticides
7. Solvents
8. Polycyclic aromatic hydrocarbons (PAH)多環芳香
Incomplete combustion of organic materials, in smoke from wood, coal, oil, tobacco, in tar and broiled foods
Carcinogens
9. Cosmetics
Allergic reactions and contact dermatitis
Bromate, cold-wave neutralizer
Thioglycolates and tioglycerol-cold-wave lotion and depilatories
Sodium hydroxide-hair straighteners
Naturally occurring toxins1. Mycotoxins2. Microbial toxins3. Plant toxins4. Animal toxins
"Toxin"=refers to toxic substances that are produced naturally
"Toxicant"=substance that is produced by anthropogenic origin
An interdisciplinary field…………Descriptive Toxicology: The science of toxicity testing to provide information for safetyevaluation and regulatory requirements.
Mechanistic Toxicology: Identification and understanding cellular, biochemical andmolecular basis by which chemicals exert toxic effects.
Regulatory Toxicology: Determination of risk based on descriptive and mechanisticstudies, and developing safety regulations.
Clinical Toxicology: Diagnosis and treatment of poisoning; evaluation of methods of detection and intoxication, mechanism of action in humans (human tox, pharmaceutical tox) and animals (veterinary tox). Integrates toxicology, clinical medicine, clinical biochemistry/pharmacology.毒藥物防治諮詢 http://www.pcc.vghtpe.gov.tw/index.asp
Occupational Toxicology: Combines occupational medicine and occupational hygeine.
Environmental Toxicology: Integrates toxicology with sub-disciplines such as ecology,wildlife and aquatic biology, environmental chemistry.
The scope of toxicity A.Mechanisms of Toxic Action
1. Biochemical toxicology
2. Behavioral toxicology-behavior is the final integrated expression of nervous function
3. Nutritional toxicology-the effects of diet
4. Carcinogenesis-cell growth
5. Teratogenesis-developmental process
6. Mutagenesis-genetic material
7. Organ toxicity-organ function
B. Measurement of toxicants and toxicity
1. Analytic toxicology
2. Toxicity testing
3. Toxicologic pathology
4. Structure-activity study
5. Biomathematics and statistics
6. Epidemiology
C. Applied Toxicology
1. Clinical toxicology
2. Veterinary toxicology
3. Forensic toxicology
4. Environmental toxicology
5. Industrial toxicology
B. Measurement of toxicants and toxicity
1. Analytic toxicology
2. Toxicity testing
3. Toxicologic pathology
4. Structure-activity study
5. Biomathematics and statistics
6. Epidemiology
C. Applied Toxicology
1. Clinical toxicology
2. Veterinary toxicology
3. Forensic toxicology
4. Environmental toxicology
5. Industrial toxicology
D. Chemical use classes
1. Agricuture chemicals
2. Clinical drugs
3. Drugs of abuse
4. Food additives
5. Industrial chemicals
6. Naturally occurring substances- phytotoxin, mycotoxin, inorganic minerals
7. Combustion products
E. Regulatory Toxicology
1. Legal aspects-formulation of
laws and regulations and their
enforcement
2. Risk assessment-
the definition of risks, potential
risks and risk- benefit equations
F. Development of antidotes
VSC/BMB497A 8
Xenobiotic
O
O
O
O O
OMe
Target OrganismCommunity/Population
Ecosystem
Absorption
Target Tissue
Target Cell
Exposure
Distribution
Metabolism
Classical
Toxicology
Xenobiotic
O
O
O
O O
OMe
MembraneTransport
OrganismToxicity
TissueToxicity
Reg
ulat
ory
Tox
icol
ogy
Excretion
Epidemiology/Environmental Toxicology
TargetMolecule
Cellular andMolecular Events
CellularToxicity
Mol
ecul
aran
d C
ellu
lar
Tox
icol
ogy
Genetic SusceptibilityBiomarkers
Risk assessment
Mechanismsand treatmentof toxicity
Risk characterization
Biology
Response
Metabolism
Toxic Effects
1. Immediate effect and delayed effect
CO, cyanide
2. Local effect and systemic effect
target organ
3. Reversible and irreversible effect
4. Anaphylactic reaction (allergic reaction)
5. Idiosyncratic reaction 特異體質反應
DoseDose by definition is the amount of a substance administered at one time.
However, other parameters are needed to characterize the exposure to xenobiotics. The most important are the number of doses, frequency, and total time period of the treatment.For example:
650 mg Tylenol as a single dose
500 mg Penicillin every 8 hours for 10 days
10 mg DDT per day for 90 days