Lecture 15-16: Toxicology Terms Flashcards
What is the definition of toxicology?
The study of the adverse effects of chemicals on living organisms. The Science of Poisons.
What is the first written record of toxicology?
Ebers Papyrus
What is Lex Cornalia ?
law passed in early Rome making it illegal to poison some one.
Who was one of the founders of toxicology that provided the dose response relationship?
Paraselsus
In the 1800s, he authored a number of significant works, among them Trait des poisons , who is this?
Martieu Orfila
field of toxicology that focuses on describing how a toxic substance affects health and well-being.
Descriptive toxicology
Mechanistic Toxicology
- field of toxicology that focuses on describing the physiological mechanism of action for a toxic substance
What is regulatory toxicology?
field of toxicology that focuses on international, federal and state regulations for a toxic substance.
What is forensic toxicology?
field of toxicology that focuses on describing how a toxic substance may be involved in the death or injury of an individual.
What is clinical toxicology?
field of toxicology that focuses on describing how a chemical substance may be potentially used as a drug to help mankind
What is enviromental toxicology?
examines how environmental exposures to chemical pollutants may present risks to biological organisms, particularly animals, birds, and fish as well as mammals including man.
What is harber’s law?
Effect= dose x time
What is LC50 and LD50?
Lethal Concentration (pollutant) or Lethal Dose (Drug) that kills 50% of the test animals in an acute toxicity test
What is EC50 and ED50?
Effective Concentration (pollutant) or Effective Dose (Drug) that may cause an adverse effect other than death in 50% of the test animals in an acute toxicity test
What is NOEC?
the concentration of a toxic substance at which no harm or mortality is observed in an acute toxicity test. Concentrations > NOEC are harmfuls.
What is LOEC?
the initial concentration of a toxic substance at which harm or mortality is observed in an acute toxicity test. This the “Threshold” for toxicity or harm
Define the term “ poisons”
any agent capable of producing a deleterious response in a biological system.
What are toxicants?
Toxic substances that are man-made or result from human (anthropogenic) activity (e.g. most toxic = Dioxin
What are toxins?
Toxic substances made by living organisms including reptiles, insects, plants and microorganisms (e.g. most toxic = Botulinum)
What are local effects?
damage at the site where a chemical first comes into contact with the body.
What are systemic effects?
generalized distribution of the chemical throughout the body by the bloodstream to internal organs.
What are target organ effects?
some chemicals may confine their effects to specific organs.
What are critical organs vs target organs?
Critical organs are the organ most affected) and Target Organ (organ with the highest level of a chemical contaminant)
Describe Additive Toxicity
two chemicals A and B, when added together are simply a sum of their individual effects (A + B = AB)
Describe synergistic toxicity
- two chemicals A and B individually are toxic, when added together interact to produce an effect that is greater than the sum of their individual effects (A+B < AB)
Define potentiation
two chemicals A and B, only A is toxic and B is nontoxic, when added together interact to produce an effect that is greater than the sum of their individual effects (A + 0 < AB)
Describe antagonistic toxicity
two chemicals A and B individually are toxic, when added together interact to produce an effect that is less than the sum of their individual effects (A+B > AB)
Describe potential carcinogens
(+ in cell lines or non vertebrate species =Screening Assays)
e.g. Aemes Assay (Bacterial Assay) - Cyclomates
Describe suspect carcinogens
( + in Screening Assay & Mammalian Species)
e.g. Saccharin – Male Rats
Describe known carcinogens
( + in Screening Assay; Mammalian Species; & Human Epidemiology
What is absorption?
process where a toxicant enters blood circulation (passes thru a membrane)
What is the membrane?
a bimolecular layer composed of proteins and lipid leaflets, 75 anstroms thick
What are “membranes”
skin (dermal), lung (inhalation) & stomach/intestine (ingestion)
What is passive transport?
primary mechanism for uptake (predicted by Log Octanol Water Coefficients = KOW). Ionized or Charged Particles do not pass thru membranes
What is KOW?
Uptake In Lipid/Uptake in Water
What is filtration?
membranes are leaky and have pores thru which small low molecular wt. compds. (MW < 100) can pass through
What is special transport?
although rare involves the movement across membranes & involves carrier molecules (e.g. proteins –PGP, Multi Drug Resistance Protein)
What is active transport?
- involves movement of a toxicant against a conc. gradient & requires an input of energy
What is facilitated transport?
involves movement of a toxicant not against a conc. gradient & not requiring energy (e.g. Calcium Binding Protein – Pb mimics Calcium).
what is endocytis?
involves membrane evagination to engulf foreign particles; very rare in the instance of high molecular weight compounds
What is pinosytis?
engulfment of liquids
What is phagocytis
engulfment of solids
What is bioconcentration
uptake from water
What is bioaccumulaton?
Uptake from food
What is sediment accumulation
Uptake from sediments
What is biomagnification?
uptake via food with each successive
trophic level increasing in concentrations (e.g. DDT, PCBs)
What is depuration
excretion of chemical contaminants via detoxification
What is the number of chemicals used in commerce?
80,000
