Toxicology Flashcards
3 areas of respiratory system
- nasopharyngeal
- tracheo-bronchial
- alveolar
Nasopharyngeal –
head, Inspirable fraction of the particulates, Major action is impaction and gravitational settling
Tracheo-bronchial-throracic fraction
major interaction impaction, 3-4 branching respiratory system (Re>2000 “laminar”) this is the conductive airway region
Alveolar
convection becomes small, Transport in this region is by diffusion and there is no cilia in the region, Alveolar microphages are primary defense,
Layers of skin
- epidermis
- dermis
Routes of entry
- inhalation
- ingestion
- absorption
- injection
Types of Immune hypersensitivity reactions
Type I - immediate hypersensitivity
Type II - cytotoxic reactions
Type III - immune complex reactions
Type IV - delayed hypersensitivity
Type I (immediate Hypersensitivity)
reactions develop in sensitized individuals immediately after a second contact with the original sensitizing antigen. (IgE antibody), Occupational asthma may be of this origin. Hives and dermal eruptions
Type II (cytotoxic reactions)
antigen is associated with surface of cell (protein or hapten), on re-exposure IgG or IgM antibodies bind to the surface initiating a series of events causing cell destruction.
Type III (Immune complex reactions)
soluble antigen binds with IgG or IgM antibodies. The binding activates complement system resulting in the formation of local immune complexes, Hypersensitivity pneumonitis (pigeon breeders disease)
Type IV (delayed hypersensitivity)
associated with contact dermatitis (Nickel)
Forced Expiratory Volume (FEV1)
the maximum flows that can be achieved-one second forced expiratory
volume
Forced Vital Capacity (FVC)
The maximum volume of air that can be rapidly exhaled
Common types of Pneumoconiosis
Asbestos - Asbestos Free Crystalline Silica- Silicosis Coal Dust- Coal miners Penumocosis "Black Lung" Silicates - Silicosis Soot & Carbon - Anthracosis Alveolar proteinosis – PNOS (Total Dust) Exp. Cotton Dust - Byssinosis Moldy Hay - Farmers Lung Iron Oxide - Siderosis Grain - Grain Asthma Moldy Sugar Cane - Bagossis
Classifications of Carcinogens (IARC)
1 Carcinogen 2A Probable Carcinogen - man 2B Probable Carcinogen - Animal 3 Non-Carcinogen 4 Probably not Carc.
Classifications of Carcinogens (ACGIH)
A1 Carcinogen A2 Suspected Carcinogen A3 Animal Carcinogen A4 Non Carcinogen A5 Not Suspected.
Types of Carcinogens
Genotoxic Carcinogen
1. Procarcinogen (direct acting) – alters DNA code
2. Inorganic – alders fidelity of replication
Epigenetic Carcinogen
3) Solid State – Asbestos
4) Hormonal – disrupts cellular differentiation
5) Immunosuppressant – allows proliferation of initiated cells
6) Co Carcinogen – modifies response of genotoxic carcinogen when co-administered
7) Promoter – promotes genotoxic response
8) Cellular Injury – Burns, radiation, etc
Organophosphates
- Parathion, malathion
- Ties up cholinesterates
- Irreversible (FA = Atropine + 2PAM)
- Measure red blood cell cholinesterase levels
Organochlorines
- (DDT, Chlorodane, Aldrin, Kepone, & other Chlorinated hydrocarbons)
- Stored in fat (lipid soluble)
- Liver, kidney, CNS damage
- Non-polar or lipid soluble
Carbamates
- Carbaryl
- Ties up cholinesterates
- Reversible (FA = Atropine only)
Aliphatic hydrocarbons
strait chained molecules
Alcohols (-OH):
Glychols have two -OH groups, glycerol have three -OH groups
Ethers and Epoxy compounds (C-O-C):
Ethyl Ether forms peroxides
Esters (R-COOR):
Used as anesthetics; causes lacrimation, vesication, and lung irritation; Cumulative usage causes organ damage.
Aldehydes (CH=O):
Aldeydes are chemical feedstocks because of their relatively high reactivity.
Volatile colorless liquids that exhibit a hazard mainly due to flammability. Acute exposure may result in pulmonary edema, bronchitis, and bronchopneumonia. Skin and pulmonary sensitization may develop in some individuals.
Ketones :
Similar effects as aldehydes. All are flammable colorless liquids with a pungent odor similar to acetone. Usage includes Industrial solvents, raw material, and intermediates in chemical syntheses.
Prolonged exposure is usually precluded by intense irritation of the eyes and respiratory system.
Aliphatic Halogenated Hydrocarbons:
Chemicals with one or two carbons replaced with halogens. Colorless, volatile liquids with excellent organic solvent properties. Halagenated hydrocarbons are flammable and have less toxicity than similar solvents with complete saturation.
Toxicity of the solvents (Fluorine > Chlorine ($) > Bromide/Iodine)
Uses include degreasing, dry-cleaning, propellants, fumigants, refrigerants, and chemical intermediates.
Aliphatic Amides:
Derivatives from ammonia (NH3); Used as chemical intermediates; Form strong alkaline solutions that are highly irritating, can cause damage on contact with eyes and skin.
Aromatics Hydrocarbons:
Characterized by the presence of an aromatic nucleus (C6H6); Vapor of aromatic hydrocarbons causes CNS depression, hepatic, renal, and bone marrow disorders. Vasodiolators
Phenols:
Substitution of an -OH group on an aromatic nucleus. Highly irritating to skin, mucous membranes and skin.
Aromatic
halogenated hydrocarbons: Used in coloring, pharmaceuticals, pesticides, and resins, chemical intermediates. Irritability to all mucous membranes and skin, powerful lacrimaters.
Aromatic Amides:
Dyestuffs and pigments. Causes Methemoglobinemia and bladder cancer
RFD (Reference Dose) –
Toxicity factors of a non-carcinogen translated from animals to humans with a margin of safety.
Slope Factor
Based on the slope of the dose response curve (for carcinogens)
NOAEL
No Observed Adverse Effects Level
NOEL
No Observed Effects Level
SNARL
Suggested No-Adverse Response Level
TD50 (Toxic Dose50)
Dose when administered produces a toxic response in 50% of the population
LD50 (Lethal Dose50)
Lethal dose to 50% of tested population (should be represented in terms of duration)
ED50 (Effective Dose50)
The dose of a particular substance that elicits an observable response to 50% of the population (should be represented in terms of duration)
Safe Exposure Levels
NOEL for most sensitive species + Safety Factor
Respiratory Irritants
Ammonia Phosgene Chlorine Hydrogen Fluoride Hydrogen Bromide Nitrogen Oxides (Silo Filler‘s disease) Sulfur Dioxide Ozone
Acetylene reacts violently with
Chlorine Fluorine Mercury Copper Silver
Types of metal diseases
Aluminum (Bauxite) – Shavers disease Yellow Phosphorus – Bone necrosis, phossy Jaw due to match heads Cadmium – "Itai-Itai" Uranium – Nephrotoxin (kidney) Antimony posing = Arsine poisoning
