PUBH 6011 FINAL REAL EXAM
QUESTIONS AND ANSWERS |
LATEST UPDATES| A GRADE
PASS!!
"The dose makes the poison" - ANSWER- - A substance's toxicity
depends on not only its chemical identity, but also on its quantity
- "All substances are poison and nothing is without poison, only the dose
permits something to not be poisonous""
How do we learn about toxicity? - ANSWER- - animal studies
- epidemiology
Epidemiology - ANSWER- - study of disease rates in human
populations with and without exposure to chemical under study
- can discover statistical association between exposure and disease
- rarely can establish a causal relationship or mechanism of disease
causation
Epidemiology: Strengths and limitations - ANSWER- Strengths:
- study species of interest
- free ranging subjects in their natural environment
Limitations:
- non-experimental
- often qualitative
- usually retrospective
- often high-dose occupational studies
(environmental exposures often much lower; may miss diseases of
,women/young/elderly)
,- subject to confounding and bias
What is toxicology? - ANSWER- - study of adverse effects in biological
systems caused by chemical or physical agents
- assess the likelihood of the occurrence of adverse effects
- study the nature and mechanisms of adverse effects
- uses model to stand in for people
Animal testing - ANSWER- - tests on rodents to assess adverse effects
- rodents chosen for short life, small size and easy care
- tests can address acute, subchronic or chronic toxicity
Toxicology animal testing - ANSWER- Strengths:
- well controlled (doses, no confounding exposure)
- prospective
Questions:
- generalized across species
-high dose to low dose extrapolation
- definition of response
Dose-response relationship - ANSWER- - toxicity quantified through
the dose-response relationship
- individual: change in severity of effect with dose
- population: change in prop. of population responding with dose
--- different for different effects
--- shape of curve gives information about pop. variability and tox of the
compound
Population dose-response function - ANSWER- - focus on a specific
endpoint
- test multiple individuals (mice or rats usually) at specific doses
- at each dose level, individuals either do or don't respond (variation
across individuals)
, - measure proportion of population responding at each dose level or
level of response at each dose level
- as dose goes up, severity goes up
Variation in response to dose - ANSWER- - differences in response due
to genes, nutrition, health status, etc.
Tolerance distribution - ANSWER- more of the population will respond
at higher doses, more of the population has tolerance to low doses
How does an agent get into the body - ANSWER- route:
- oral
- dermal
- inhalation
timing:
- acute (days)
- sub-chronic (weeks to months)
- chronic (months to years)
Equivalent doses - ANSWER- - use mg/kg to make equivalent doses
across species
Acute toxicity - ANSWER- adverse effects that occur within a short
period after exposure to a toxicant; often reversible, usually from a
single dose
Chronic toxicity - ANSWER- adverse effects that occur some time after
exposure to a toxicant or after extended exposure to the toxicant; ex
cancer, liver damage, lung fibrosis
Local toxicity - ANSWER- toxic effect occurs at the site of exposure (ex
pulmonary edema, acid on skin)
systemic toxicity - ANSWER- requires absorption and distribution of the
toxicant (usually in the blood stream) to susceptible organs where the
QUESTIONS AND ANSWERS |
LATEST UPDATES| A GRADE
PASS!!
"The dose makes the poison" - ANSWER- - A substance's toxicity
depends on not only its chemical identity, but also on its quantity
- "All substances are poison and nothing is without poison, only the dose
permits something to not be poisonous""
How do we learn about toxicity? - ANSWER- - animal studies
- epidemiology
Epidemiology - ANSWER- - study of disease rates in human
populations with and without exposure to chemical under study
- can discover statistical association between exposure and disease
- rarely can establish a causal relationship or mechanism of disease
causation
Epidemiology: Strengths and limitations - ANSWER- Strengths:
- study species of interest
- free ranging subjects in their natural environment
Limitations:
- non-experimental
- often qualitative
- usually retrospective
- often high-dose occupational studies
(environmental exposures often much lower; may miss diseases of
,women/young/elderly)
,- subject to confounding and bias
What is toxicology? - ANSWER- - study of adverse effects in biological
systems caused by chemical or physical agents
- assess the likelihood of the occurrence of adverse effects
- study the nature and mechanisms of adverse effects
- uses model to stand in for people
Animal testing - ANSWER- - tests on rodents to assess adverse effects
- rodents chosen for short life, small size and easy care
- tests can address acute, subchronic or chronic toxicity
Toxicology animal testing - ANSWER- Strengths:
- well controlled (doses, no confounding exposure)
- prospective
Questions:
- generalized across species
-high dose to low dose extrapolation
- definition of response
Dose-response relationship - ANSWER- - toxicity quantified through
the dose-response relationship
- individual: change in severity of effect with dose
- population: change in prop. of population responding with dose
--- different for different effects
--- shape of curve gives information about pop. variability and tox of the
compound
Population dose-response function - ANSWER- - focus on a specific
endpoint
- test multiple individuals (mice or rats usually) at specific doses
- at each dose level, individuals either do or don't respond (variation
across individuals)
, - measure proportion of population responding at each dose level or
level of response at each dose level
- as dose goes up, severity goes up
Variation in response to dose - ANSWER- - differences in response due
to genes, nutrition, health status, etc.
Tolerance distribution - ANSWER- more of the population will respond
at higher doses, more of the population has tolerance to low doses
How does an agent get into the body - ANSWER- route:
- oral
- dermal
- inhalation
timing:
- acute (days)
- sub-chronic (weeks to months)
- chronic (months to years)
Equivalent doses - ANSWER- - use mg/kg to make equivalent doses
across species
Acute toxicity - ANSWER- adverse effects that occur within a short
period after exposure to a toxicant; often reversible, usually from a
single dose
Chronic toxicity - ANSWER- adverse effects that occur some time after
exposure to a toxicant or after extended exposure to the toxicant; ex
cancer, liver damage, lung fibrosis
Local toxicity - ANSWER- toxic effect occurs at the site of exposure (ex
pulmonary edema, acid on skin)
systemic toxicity - ANSWER- requires absorption and distribution of the
toxicant (usually in the blood stream) to susceptible organs where the
