Exam 3: Lecture 11, Toxicity of Specific Chemicals Flashcards

1
Q

5 Major substances of air pollution?

A
Co = 52%
Sulfur Oxides = 14%
Hydrocarbons = 14%
Nitrogen Oxides = 14%
Particulate matter = 4%
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2
Q

air pollution implicated as contributing factor for….

A
Bronchitis
Obstructive Ventilatory disease
Pulmonary emphysema
Bronchial Asthma
Lung Cancer
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3
Q

Carbon monoxide info

A

combines reversibly with oxygen binding sites of hemoglobin and has affinity for hemoglobin that is 220 times that of 02

brain and heart most effected

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4
Q

Sulfur Dioxide info

A

approx 90% inhaled is absorbed in upper respiratory tract = site of principle effect

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5
Q

Carbon tetrachloride and trichloroethylene have….

A

largely bene removed from workplace due to carcinogenic potential

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6
Q

Tetrachloroethylene and trichloroethane are…

A

still used for dry cleaning and solvent degreasing, but likely limited use in future

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7
Q

Fluorinated Aliphatics

A

use limited by agreements due to severe environmental damage

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8
Q

Halogenated aliphatic solvents can cause….

A

depressant of CNS (chloroform = most potent)

Impaired memory and peripheral neuropathy

Hepatotoxicity in humans after acute/chronic exposure (Carbon tetrachloride most potent)

Nephrotoxicity in humans

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9
Q

Benzene info

A

important composent of gasoline

Acute toxic event = CNS depression
Fatal dose: 7500ppm/30 min

chronic exposure = toxic, bone marrow injury, associated leukemia

most organizations classify as known human carcinogen

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10
Q

toluene

A

CNS depressant, skin/eye irritant

exposure to 800ppm can lead to severe fatigue

doesn’t possess myelotoxic properties of benzene/associated with leukemia

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11
Q

Xylene

A

CNS depressant and skin irritant

doesn’t possess myelotoxic properties of benzene/associated with leukemia

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12
Q

Organochlorine Pesticides major effect is…

A

impact on CNS stimulation

interfere with inactivation of Na channel in excitable membranes, inhibit Ca ion transport

affect depolarization and enhance excitability

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13
Q

DDT manifestations

A

tremor 1st, possibly convulsions

no Treatment

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14
Q

Organophosphorus Pesticides

A

Major effect is inhibition of acetylcholinesterase

absorbed by skin, respiratory and GI tract

causes altered neurologic and cognitive functions,

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15
Q

Carbamate Pesticides

A

inhibit acetylcholinesterase

clinical effects are shorter duration than those observed with organophosphorus compound

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16
Q

Chlorophenoxy Herbicides

A

2,4-D ad 2,4,5-T
Toxicity rating of 4/3

can cause coma and generalized muscle hypotonia

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17
Q

Most important Chlorophenoxy Herbicide

A

Dioxin

Likely human carcinogen

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18
Q

Glyphosate Herbicide

A

most injuries minor, some can be lethal
eye/skin irritant
less potent than bipyridyl herbicides

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19
Q

Bipyridyl herbicides

A

Paraquat is most important

Toxicity rating of 4 (50-500mg/kg)

Lethal intoxication been reported

paraquat accumulates in lungs, causes lung edema, alveolitis and progressive fibrosis

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20
Q

Polychlorinated biphenyls

A

most important is TCDD

food major source of contamination

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21
Q

Endocrine Disruptors

A

DDT and PCBs

concerns: increasing contamination of enviornment, appearance of bioaccumulation and potential for toxicity

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22
Q

Asbestos

A

widely used in industry for over 100 yrs

all forms shown to cause progressive lung disease

23
Q

Toxic heavy metals interfere with…

A

function of essential cations

cause enzyme inhibition, oxidative stress and alter gene expression

24
Q

Soluble arsenic compounds well absorbed through

A

respiratory and GI tract

25
Most absorbed form of arsenic is...
inorganic
26
Trivalent vs pentavalent arsenic?
trivalent = 2-10 times more toxic
27
Actue inorganic arsenic poisoning
can be confirmed by demonstration of elevated amounts of inorganic arsenic/its metabolites in urine arsenic disappears rapidly from blood, except in anuric patients, blood arsenic levels should not be used as diagnostic
28
Acute arsenic treatment
unithiol, 3-5 mg/kg IV every 4-6hrs or dimercaprol, 3-5 mg/kg IM every 4-6hr
29
Arsine gas poisoning
currently available chelating agents haven't shown clinical value after latent period 2/24 hr, massive IV hemolysis may occur
30
Adult % lead absorbed?
10-15%
31
Children % lead absorbed?
up to 50%
32
Lead Half-life in blood/soft tissues
1-2 months
33
Lead Half-life in skeleton
years to decades
34
systems lead can effect
Nervous Reproductive GI Cardiovascular
35
Acute inorganic lead poisoning
uncommon today
36
Chronic inorganic lead poisoning
diagnosis of lead intoxication is best confirmed by measuring lead in whole blood pt presents with multi systemic findings, difficulty concentrating, irritability, depressed mood
37
treatment of Lead poisoning
IV EDTA admin 30-50 mg/kg/d continuous infusion up to 5 day
38
organolead poisoning
very rare initial treatment = decontaminating, treat seizures and chelation if high blood/lead conc
39
primary source of occupational exposure mercury?
inhaled
40
Mercury distribution
excreted through urine and feces highest conc in kidney most excreted within weeks/months but fraction retained in kidney/brain for years
41
blood and whole body half-life of mercury is...
50 days
42
Acute mercury poisoning
potentially life threatening
43
chronic mercury poisoning
symptoms; change in mood, withdrawal, depression, explosive anger or blushing
44
Dimethylmercury is
rarely encountered by extremely neurotoxic form of organomercury that maybe lethal in small quantities
45
Acute exposure treatment mercury
prompt chelation with oral and IV unithiol, IM dimercaprol, or oral succimer
46
Chronic Exposure treatment mercury
Dimercaprol not recommended, distributes metal to CNS Unithiol and Succimer for chronic exposure
47
Chelators
contain one of more coordinating atom, usually Oxygen/sulfer/nitrogen used to prevent or reverse toxic effects of heavy metals
48
Dimercaprol
known as British Anti-lewisite (BAL) has to be given in peanut oil water soluble analogs (unithiol and succimer) have higher therapeutics
49
Unithiol given...
IV
50
Succimer is given..
Oraly
51
to Prevent potentially life-threatening Ca depletion, Eda should be admin as
calcium disodium salt
52
Chelator of choice for iron poisoning?
Deferoxamine
53
Prussian Blue
approved for treatment of contamination with radioactive cesium and intoxication with thallium salts