toxicology

• all substances are poison, the right dose ..
• -contributer to dose response relationship
• -founder of modern toxicology
• -notion of target organ

• adverse effects of chemicals on living organisms
• -study of how xenobiotics (chemical compounds) affect biological systems

investigates the adverse effects of chemicals including their celluar, biochemical, and molecular mechanisms of action and asesses the probablity of their occurance.

• 1. human body
• 2. genes-control organ develp and function
• 3. germ cells-involve reproduction
• 4. somatic cells-all other parts of the body
• 5. cells may grow in an organ in uncontrollable ways.

• 1. viral infection (onocogenic viruses Hep C and HPV)
• 2. environmental agents (certain chemicals)

• 80, 0000 chemicala in common use world-wide
• 200___ to 2000 new chemicals/year
• exposures: (3) at home wor,k environment
• esistence: (4) in the food, air, soil, water
• related to #2 cause of death-cancer (environmental exposures)

• 1. molecular structure
• 2. physical characteristics
• 3. sources
• 4. end uses
• 5. toxic properties

• type I- (a-e) based on combo of physical and chemical prop, toxic effects and use (toxic chemicals, fibers and dust) 
• type II- (a-g) mechanisms of toxicity(carcinogens, neurotoxins, mutagens, allergens)

unregulated growth of cells

a clump of cancer cells

an alteration in the DNA of the germ cells.

a substance that causes a mutation

the agents believed to cause cancer

any agent capable of producing a deleterious response in a biological system

any substance whose physiological action is harmful to health

the combined effect of the two chemical is greater than the sum of the...

refers to a toxic substance made by living orgaisms including reptiles, insects, plants and microorganisms

the degree to which something is posionous-related to physical and chemical properties.

• 1.bacteria-botulinum
• 2. fungi-myco
• 3. algae-phyco
• 4. plants- phyto
• 5. animals-zoo toxins

toxic substances that are man-made

• 1. unless exposed to toxic substances no toxic effect on human health
• 2. Key factors: manifestation and magnitude
• 3. not all exposure will lead to a toxic manifestation

• 1. regulatory
• 2. forensic
• 3. clinical
• 4. environmental
• 5. reproductive
• 6. developmental

• examines how environmental exposures to chemical pollutants may present risks to biological organisms, particularly animals, birds, and fish 
• -production, fate and effect of the natural and synthetic pollutants in the environment

• manufactured
• natural
• unintentionally produced

• poisonous materials
• toxic plants
• volcanoes
• animal sting/bite

• essential for a specific application
• large category

• 1. unwanted material-byproducts
• 2. generated in many industrial processes
• 3. impurity in starting materials 
• 4. side reaction of complex chemical pathways

• route of entry
• dose
• duration
• susceptibility
• possible synergistic effects

• gastrointensina tract
• respitotory system
• contact with surface skin
• injection into blood stream (blood transplant)

• 1.absorb-skin-irritation-into circulatory system, 
• 2. ingestion-mouth and stomach-irriation-circulatory system via biliary-hepatic system distribution
• 3. inhalation-lungs-irritation, particulate, entrapment-alveolar space-through capillaries, circulatory system

• 1. exposure dose-amt encountered in envir
• 2. absorbed-(avail internal organs)
• 3. administered
• 4. total-adding individ dose
• 5. external-aquired by contact-
• 6. internal-portion that is internalized
• 7. biologically effective

• the doase mg/kg of body weight causing death in 50% of animals
• -used to compare chemicals

correlative relationship bw the charactertistics of exposure to chemicals and the spectrum of effects caused by the chemical

• acute-o-24hrs
• subacute-less than one month
• subchronic-1-3 month
• chronic-3 plus

• 1. local effects-damage at the site where a chemicals first comes into contact with the body (cell replacement)
• 2. systemic effects-generalized distribution of the chemical throughout the body by the bloodstream to internal organs (damage to enzyme system)
• 3. target organ effects-some chemical may confine their effects to specific organs (DNA damage)

time period bw initial exposure and measureable response

• additive
• synergism
• potentiation (2 chemical bring it out)
• antagonism

• subjects used for testing
• 1. volunteers
• 2. animals exposed purposively (in vitro)
• 3. cells derived from human, animal or plant sources.

• 1.often difficult to determine
• 2. use eipdemiology
• 3. immunobiological test
• 4. lab test with animal model, cell culcture
• 5. ames test
• 6. ecological risk assessment

-ids the presence of absense of toxins in the environment

• -1970
• mutagen test-if it can grow in the environment it may be a mutagent

• qualitative/quantitative appraissal for actual or potential effect of a contaminant chemical on wildlife
• 1. problem formulation
• 2. analyis
• 3. risk characterization

qualitative or quantitative estimation of the likelihood of adverse effects that may resuls from exposure to specified health hazards or from the absence of beneficial influence.

• 1. hazard id
• 2. dose-response relationship
• 3. exposure assessment-id populations exposed, examines roots, magntitude and frequency)
• 4. risk characterization -estimates number of excess unwarranted health events expected at diff time intervals at each level of exposure

• 1. exposure standards
• 2. requirements for pre-market testing
• 3. recalls of toxic products
• 4. banning hazardous materials
• 5. develop, eval, and implementation of regulatory options, aimed at risk reduction.

• 1. incineration
• 2. dumping
• 3. land filling
• 4. land application
• 5. deep-well injection