Toxicology Flashcards
True or False
Labs help identify and quantitate specific toxic substances like
-household items that can be considered toxic/poison
-illicit drugs / prescription drugs
-Heavy metals
-Miscellaneous materials
True
Highest incidence of toxic substances occurs in which set of population
Highest in kids(less than 5yrs old)>teens (tide-pods)>adults
What are Xenobiotics?
Chemicals/ drugs that are NOT normally found or produced in the body
Define Toxicology
The study of adverse effects of Xenobiotics in humans
Scope of toxicity is broad. What are the 3 Major Disciplines
last one starts with an R
Mechanistic
Descriptive
Regulatory
Explain the Mechanistic discipline
-To make explain the molecular/cellular/biochemical effects of Xenobiotics
w/in the context of a dose-response relationship
between the xenobiotics and its adverse effects
-It the basis of rational therapy
&
the development of lab tests to asses the degree of exposure
Explain the Descriptive discipline
-Risk assessment
-Uses animal (results) to experiments to predict the level of exposure that will cause harm to humans
Explain the Regulatory discipline
Data from both mechanistic & Descriptive
are used to establish STANDARDS that define the level of exposure that will NOT pose a risk to public health/safety
-Most regulatory toxicologist work w/ the government.
What are the specialties w/in toxicology
Forensic
Clinical
Environmental
Forensic speciality does what?
-Primary concern with the medical & legal consequences of exposure
-Focus on the establishing & validating the analytic performance of test methods
which are used to generate legal situations
including cases of death
Clinical speciality does what?
-Focus on relationship between xenobiotics & disease states
-Emphasis on diagnostic testing & therapeutic intervention
Environmental speciality does what?
-Evaluates the environmental chemical pollutants & their impacts on human health
True or False
Toxicology is usually NOT part of the clinical chemistry as a specialty
False: It is usually considered part of clinical chemistry
True or False
Xenobiotics, Poisons, and Toxins
are used interchangeably
True
What is the commonality between Xenobiotics and poisons?
Both exogenous agents that can have an adverse effect on a living organism
What are Xenobiotics?
Describe environmental exposure to chemicals or drugs
(antibiotics, antidepressants,
perfluorinated &
brominated compounds)
What are Poisons?
Describe substances from an animal/ plant/ mineral, or gas
(venoms from snakes or spiders, poison hemlock,
arsenic, lead,
carbon monoxide)
What are Toxins?
Endogenous substances that are biologically synthesized in living cells or microorganisms
Ex:
Botulinum toxin from Clostridium Botulinum
Hemotoxins from snakes
Mycotoxins produced from fungi
What are Toxicant and toxic?
Refers to substances that are NOT produced within a living cell or microorganism
AND
are more commonly used to describe environmental chemicals
True or False
50% are due to accidental exposures
&
30% are poisoning cases are due to suicide attempts
&
the rest are homicidal & occupational exposure
FALSE:
50% are suicide attempts (highest mortality rate)
30% are due to accidental exposures (frequent in kids/teens & seen w/ adults for therapeutic & illicit drugs instances)
the rest, is True (homicidal & occupational)
True or False
Ingestion is one of the most common routes of exposure and must be absorbed into circulation to exert a systemic effect.
True
Which of the following are is NOT true when it comes to passive diffusion
A. Must be able to cross cellular barriers
B. Hydrophobic can
C. Ionized can’t
D. Weak acids become protonated in gastric acid—becomes ionized- and are absorbed in stomach
E. Weak bases—absorbed in intestine
D. It becomes NONionized- and gets absorbed in stomach
Which of the following factors ALSO influence the rate of diffusion
A. Rate of dissolution
B. GI motility
C. Resistance to degradation in GI tract
D. Interaction with other substances
E. Only A
F. All of the above
F. All of the above
True or False
Toxins not absorbed in GI tract can produce local effects like diarrhea, bleeding, and malabsorption
True
Which is NOT true for the Dose-response Relationship
A. central theme to toxicology
B. assessing a substance potential to cause pathological effects
C. require an index of the relative toxicity of substances
D. most xenobiotics can produce pathological effects other than death
E. must correlate the dose of a xenobiotic that will result in harmful effects
F. correlates to a single oral dose to probability of a lethal outcome in an average 80kg male
G. all true
F. Should be average 70kg male
Which is true regarding Dose-response relationship
A. Used to evaluate responses over a narrow range of concentrations
B. toxic responses OR response associated with a pathological effects, increases the the lethal dose
C. Evaluates data from a cumulative frequency histogram to toxic responses over a range of doses
D. Determined to be the indicator of the toxic effects specific for many toxins
E. All the above
Answer
C. Evaluates data from a cumulative frequency histogram to toxic responses over a rang of doses
Corrected versions
A. Used to evaluate responses over a wide range of concentrations
B. toxic responses & pathological effects, lowers the the lethal dose
D. Determined to be the indicator of the toxic effects specific for that toxin
What does TD50 mean?
The predicted dose that would produce a Toxic response in 50% of the population
Toxic dose
What does ED50 mean?
The predicted dose to have a therapeutic benefit or be effective in 50% of the population
Effective dose
What does LD50 mean?
The predicted does that would result in death for 50% of the population
Lethal dose
What is the therapeutic index? (TI)
Ratio of TD or LD over ED
TI= TD50/ED50
or
TI= LD50/ED50
What is the benefit of a large therapeutic index (TI)?
Fewer adverse effects/toxic effects when dose is within therapeutic range (T.R.)
True or False
The measure of GGT or ALT can be used to evaluate liver cells?
True
True or False
All individuals respond display the same response to the same dose
False
What is the Quantal dose-relationship
Describes the changes in health effects
of a defined population
Based on
the exposure to the xenobiotic
What is acute toxicity?
Usually single, short-term exposure
to a substance in which the dose is sufficient to cause
immediate toxic effects
What is chronic toxicity?
Generally associated with repeated & frequent exposure for extended time periods (months to years)
at doses that are insufficient to cause an immediate acute response
True of False
Chronic toxicity can affect different systems than acute?
True
True or False
Signs and symptoms of toxicity are specific and don’r rely on lab testing?
False
They are NONspecific and DO require lab testing
Which is not a reason for toxic testing
A. Drug screen
B. Heavy metal panels
C. Environmental risk of exposure
D. Support investigation of exposure or confirm clinical suspicion of poisonings
E. Comply with occupational regulations/guidelines
F. All are true
F. ALL are reasons for testing
Which is not used for specimen type testing
A. Blood/urine
B. Serum/ plasma
C. Hair
D. Nails
E. synovial/ oral fluid
E. Oral fluid is a specimen type, but not synovial fluid.
What is Toxicokinetics?
When toxic agents exhibit unique absorption, distribution, metabolism, and elimination
Pre-analytic variables excludes which of the following?
A. Elimination patterns
B. Analyte stability
C. Specimen collection procedures
D. Urine collected at 24hrs is the preference
E. Dose of xenobiotic
E. is excluded
The rest ARE pre-analytical variables