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Tox Exam 1 > Exam 1 > Flashcards

Exam 1 Flashcards

1
Q

The interaction of chemicals in toxicology includes all of the following except:

A

Subtractive

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2
Q

Paracelsus was an expert in all of the following professions except:

A

Astrophysicist

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3
Q

Which of the following is not considered a phase II biotransformation?

A

Epoxide hydration

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4
Q

Toxicology may be defined as the study of:

A

The adverse effects of chemicals in living systems

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5
Q

Toxicants may move across biological membranes by all of the following mechanisms except:

A

Aqueous hydrolysis

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6
Q

Which of the following statements best characterizes synergism?

A

Synergism occurs if two chemicals with a similar action, when given together, produce an effect that is greater in magnitude than the sum of the effects when the chemicals are given individually

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7
Q

Biotransformation reactions generally produce a product that is:

A

less lipid-soluble than the original chemical

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8
Q

A toxicant’s distribution to a specific tissue does not:

A

Increase for xenobiotics that are bound to plasma proteins

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9
Q

High-energy cofactors that are NOT involved in phase II reactions include:

A

Amino acids such as taurine and glycine

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10
Q

Now that you know that all chemicals are toxic, which of the following corollary statements is false?

A

Exposure limits may be set for all chemicals that will instill confidence that we are safe from chemicals

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11
Q

Toxicology testing in the 21st century will include in silico testing of chemicals. Advantages are numerous when compared with standard bioassasys, but some problems still need to be worked out. These problems include:

A

Predictive analyses, more informative, and efficient

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12
Q

True or False. Pesticides are ubiquitous and present to the environment in a diversity of 900 ingredients composing 35,000 commercial products with billions of pounds being being released to the global environment annually.

A

True

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13
Q

Which type of pesticide inhibits the acetylcholinesterase enzyme and with chronic exposure may result in neuropathy characterized by weakness or paralysis of the arms and legs?

A

Organophosphates

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14
Q

Which of the following statements is false?
A. glucuronide conjugates are excreted readily by the kidneys
B. a lipid-soluble xenobiotic metabolite will sequester in fatty tissue
C. acidification of the urine may help trap acidic drugs in urine
D. for a weakly acidic drug (pKa+3) at equilibrium, the ratio of nonionized to ionized drug (HA/A-) equals 1 when the pH of the medium is 3

A

C. acidification of the urine may help trap acidic drugs in urine

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15
Q

Induction of xenobiotic biotransformation by exposure to a toxicant will:

A

Result in increased amounts of enzymes in the ER

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16
Q

Steps for liver ridding body of toxins

A
  1. introduce oxygen (phase I)
  2. create charge separated species (bioactivation)
  3. Mechanisms try and force compounds to elimination
  4. Tripeptide (GSH) sucks up reactive oxygen compounds (phase 2)
  5. Result is R-O-Y, eliminated in feces
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17
Q

What is risk assessment?

A

quantitative estimate of the potential effects on human health to illuminate the significance of exposure to chemicals in the environment

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18
Q

What is a poison?

A

any agent capable of producing a deleterious response in a biological system

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19
Q

What is the difference between a toxin and a toxicant?

A

toxin- produced by biological system (plants, fungi, animals, bacteria)

toxicant- produced or by-product of anthropogenic activity

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20
Q

What are the three stages in the history of toxicology?

A
  1. antiquity
  2. Middle Ages
  3. Age of Enlightenment
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21
Q

Who developed a method for arsenic analysis?

A

Marsh, 1836

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22
Q

Who developed a method for separating As and Hg?

A

Reinsh, 1841

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23
Q

Who detected and identified phosphorus?

A

Stas-Otto, 1951

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24
Q

What is the Delaney Cause (1958)?

A

any chemical found to be carcinogenic in lab animals or humans could not be added to the food supply

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25
Q

What is regulatory toxicology?

A

determining whether a drug or chemical poses a low enough risk based on mechanistic and descriptive data

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26
Q

What is mechanistic toxicology?

A

identifies and investigates cellular, biochemical, & molecular mechanisms by which chemicals exert their influence

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27
Q

What is descriptive toxicology?

A

concerned with toxicity testing and evaluating the safety of certain substances

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28
Q

What are the responsibilities of legislation?

A
  1. protect human health and the env. from pesticides and waste disposal
  2. conserve energy and natural resources
  3. reduce generated waste, and ensure waste is managed in an environmentally sound manner
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29
Q

How are toxic agents classified?

A
  1. target organ (i.e. hematopoietic system)
  2. use (i.e. pesticides)
  3. source (i.e. toxin/toxicant)
  4. effects (i.e. cancer/liver injury)
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30
Q

What are some undesired effects of toxic agents?

A
  1. allergic reactions/hypersensitivity
  2. immediate vs. delayed toxicity
  3. reversible vs. irreversible effects
  4. local vs. systemic toxicity
  5. interaction of chemicals
  6. tolerance
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31
Q

What is a hapten?

A

a molecule combines with an endogenous protein to cause an allergic reaction

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32
Q

What are the four ways chemicals interact?

A
  1. Additive (1+1=2)
  2. Synergistic (1+1=>2)
  3. Potentiation (0+1>1)
  4. Antagonism (1+1
33
Q

What are the multiple mechanisms for antagonism?

A
  1. functional
  2. chemical
  3. dispositional
  4. receptor
34
Q

What are the major routes of chemical exposure?

A
  1. ingestion
  2. inhalation
  3. dermal
  4. parenteral routes
35
Q

What is slope indicative of in a dose-response relationship?

A

half life

36
Q

What does time to toxicity depend on?

A
  1. frequency of administration
  2. dose level
  3. time to recover between doses
37
Q

What is a quantal dose-response relationship?

A
  1. “all or non”

2. at any dose, any individual in the population either does or does not responsd

38
Q

What is hormesis?

A

xenobiotics may cause stimulatory effects at low dose but adverse effects at high doses

39
Q

Where do ED, TD, and LD lie on a dose-response graph by comparison?

A

ED- left shifted
TD- center
LD- right shifted

40
Q

What is potency?

A

the range of doses over which a chemical produces increasing responses

41
Q

What is allometry?

A

the study of the relationship between body weight and physiology

42
Q

What is NOAEL?

A

no observable adverse effect level

43
Q

What are the major functions of the liver?

A
  1. maintain metabolic homeostasis

2. bile formation

44
Q

Where does bioreactivation (R-O-Y)?

A

hepatocytes

45
Q

What are the three zones of the acinus, or functional hepatic unit?

A
  1. closest to the entry of blood
  2. intermediate
  3. abuts the terminal hepatic vein
46
Q

What cells act as macrophages in the liver?

A

Kupffer cells

47
Q

What happens when the liver dysfunctions due to toxins?

A
  1. high secretios of metabolites
  2. inhibition of bilirubin uptake
  3. inhibition of clotting factor secretion
48
Q

What are some types of injuries of the liver due to toxic chemicals?

A
  1. fatty liver
  2. cell death
  3. canalicular cholestasis
  4. bile duct damage
  5. sinusoidal disorders
  6. fibrosis and cirrhosis
  7. tumors
49
Q

What do activated Kupffer cells secrete?

A

cytotoxins (ROS and RNS)

50
Q

What are phase I reactions?

A

hydrolysis
reduction
oxidation

51
Q

What are phase II reactions?

A

conjugation

52
Q

What components in phase II reactions can cause organ damage?

A

charge separated species

53
Q

What are the steps in benzo(a)pyrene activation?

A
  1. receptor (AhR) bind to BAP to form complex
  2. ARNT pulls complex into nucleus
  3. Complex sits on a promoter
  4. Complex initiates expression of CYP450
54
Q

What leads to suppression of hematopoiesis in bone marrow?

A

CYP450 activation of benzene

55
Q

What is the goal of toxicology?

A
  1. hazard identification
  2. dose-response assessment
  3. exposure assessment
  4. risk characterization
56
Q

What are the three most commonly used forms of asbestos used commercially?

A

Chrysotile
Amosite
Crocidolite

57
Q

What diseases do fleas carry?

A

Plague

Murine typhus

58
Q

What diseases do lice carry?

A

Typhus

Relapsing fever

59
Q

What diseases do sand flies carry?

A

Pappataci fever
Three-day fever
Sandfly fever
Phlebovirus

60
Q

What diseases can mice carry?

A

Rat-bite fever
Weil’s disease
Hantavirus pulmonary syndrome

61
Q

What molecules do organophosphates and carbamates inactivate?

A

acetylcholinesterase

62
Q

What are the manifestations of developmental toxicology?

A
  1. structural malformations
  2. growth retardation
  3. functional impairment
  4. death of the organism
63
Q

What are some human developmental toxicants?

A

Radiation
Infection
Maternal trauma and metabolic imbalances
Drugs/chemicals

64
Q

What is the threshold phenomenon in developmental tox?

A

That a maternal dosage below which an adverse response is not elicited because some repair or defense system is able to combat exposure

65
Q

What maternal factors affect fetal development?

A 
Genetics
Disease
Nutrition
Stress
Placental toxicity
Maternal toxicity
66
Q

What is the Barker Hypothesis (Susceptibility Exposure Paradigm)?

A

the effects of early childhood exposure may not be apparent until later in life

67
Q

What does ADME stand for?

A

Absorption
Distribution
Metabolism
Excretion

68
Q

What is step one of the mechanisms of toxicology?

A

Delivery from the site of exposure to the targe

69
Q

What are the two possible outcomes of step one of the mechanisms of tox?

A

Absorption

Pre-systemic elimination

70
Q

What path does a first-path effect take?

A 
Drug
Digestive system
Portal circulation
Liver
Extensively metabolized
71
Q

Where does reabsorption of chemicals take place?

A

kidney

GI tract

72
Q

What is involved with the toxification of numerous chemicals?

A

formation of electrophiles

73
Q

What are there no efficient elimination mechanisms for?

A

nonvolatile, highly lipophilic chemicals

74
Q

What does phase II metabolism eliminate to prevent its biotransformation?

A

the ultimate toxicant

75
Q

What is the second step of the mechanisms of tox?

A

reaction of the ultimate toxicant with target molecule

76
Q

What is the third step of the mechanisms of tox?

A

cellular dysfunction and resultant toxicities

77
Q

What is step 4 of the mechanisms of tox?

A

repair or dysrepair

78
Q

What happens when repair fails in the mechanisms of tox?

A

Tissue necrosis
Fibrosis
Carcinogenesis

Tox Exam 1 (1 decks)

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