Lecture 3: Variation in Toxic Responses Flashcards

1
Q

What is a toxin?

A

Toxin generally refers to toxic substances that are produced by biological systems such as plants, animals, fungi, or bacteria.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is a toxicant?

A

Toxicant describes toxic substances that are produced by or are a by-product of anthropogenic (human-made).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Factors determining adverse effects?

A
  • Intrinsic toxicity
  • Dose
  • Exposure conditions
  • Response of host
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are biomarkers?

A

Biomarkers are chemicals, metabolites, susceptibility characteristics, or changes in the body that relate to the exposure of an organism to a chemical.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How can toxicity of a chemical be determined?

A
  1. Epidemiology
  2. In vivo
  3. In vitro
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How can we determine toxicity by Epidemiology?

A

By observing human, animal, or plant populations exposed to a chemical.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How can we determine toxicity by In vivo?

A

By administering the chemical to animals or plants under controlled conditions and observing the effects

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How can we determine toxicity by in vitro?

A

By exposing cells, subcellular fractions, or single-celled organisms to the chemical

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are Cyanotoxins?

A

These are (hepatoxin) are toxins that are produced by bacteria called cyanobacteria or blue algae.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is hepatotoxicity?

A

Damage to the liver caused by a medicine, chemical, or herbal or dietary supplement.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What causes blood and cardiovascular toxicity?

A

damage to the liver caused by a medicine, chemical, or herbal or dietary supplement.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What causes dermal toxcity?

A

This toxicity may occur when a toxicant comes into direct contact with the skin
or the toxicant is distributed to the skin internally.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is eye toxcity?

A

This toxicity is as a results of direct contact with a toxicant/toxin or internal
distribution to the eye.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is immunotoxicity?

A

Immunotoxicity is toxicity of the immune system which takes numerous forms:
* Hypersensitivity (allergy and autoimmunity)
* Immunodeficiency
* Uncontrolled proliferation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How does nephrotoxicity occur?

A

The Kidneys is susceptible to toxicants as a result of its high volume of
blood flows through the organ thus filtering large amounts of toxins which
can concentrate inside our kidney tubules.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is nephrotoxicity ?

A

The toxicity to the kidneys.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is neurotoxicity?

A

Neurotoxicity involve toxicant damages to cells of the central nervous system (brain and spinal cord) and the peripheral nervous system (nerves outside the CNS).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the primary types of neurotoxicity?

A

Neuronopathies (neuron injury)
* Axonopathies (axon injury)
* Demyelination (loss of axon insulation)
* Interference with neurotransmission

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is reproductive toxicity?

A

This toxicity involves toxicant damage to either the male or female reproductive system.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is Respiratory Toxicity?

A

This toxicity relates to effects on the upper respiratory system (nose, pharynx, larynx, and trachea) and the lower respiratory system (bronchi, bronchioles, and lung alveoli)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is selective toxicity?

A

A drug is harmful to a pathogen without being harmful to the host.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is therapuetic index?

A

The ratio of the dose required to produce a toxic effect and the dose needed to elicit the desired therapeutic response.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is a disadvantage of selective toxicity?

A

Because of biodiversity, it is not always possible to predict the toxic effect on humans and laboratory animals.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is mechanism of action?

A

A term used to describe how a drug or other substance produces an effect in the body.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is an agonist?

A

a drug that binds to the receptor, producing a similar response to the intended chemical and receptor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is an antagonist?

A

a drug that binds to the receptor either on the primary site, or on another site, which all together stops the receptor from producing a response.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is sub acute exposure in Animal Toxicity Tests?

A

Exposure to chemical for 1 month or less

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is sub chronic exposure in Animal Toxicity Tests?

A

Exposure to chemical for 1-3
months.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is chronic exposure in Animal Toxicity Tests?

A

Exposure to chemical for more than 3 months

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What are the two principle of animal toxicity test?

A
  1. Any information about toxicity gleaned from laboratory animals, are applicable to humans.
  2. That a high toxic dosage is needed for use in experimental exercises. It is a valid and accepted method.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What is the aim of Animal Toxicity Tests?

A

They are done to prove that chemicals have the potential to cause toxic effects, and not done to prove if chemicals are safe.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Good Laboratory Practice Guidelines Test what in Descriptive Animal Toxicity Tests?

A
  1. Acute Lethality
  2. Skin and Eye Irritation
  3. Sub-acute
  4. Sub-chronic
  5. Chronic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What is Acute Lethality Test purpose?

A

– Compare the LD50 to other known compounds
– Identify target organs for the toxic agent if any
– Identify a remedy for the toxic response
– Provide a dose-range guide for other studies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What is drug concentration?

A

Concentration is a measure of the amount of dissolved substance contained per unit of volume.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What is drug dosage?

A

Dose is the amount of a substance administered at one time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What are types of dose?

A
  1. Exposure dose
  2. Absorbed dose
  3. Administered dose
  4. Total dose
37
Q

What is exposure dose?

A

This is the amount of senobiotic encountered in the environment.

38
Q

What is absorbed dose?

A

This is the actual amount of the exposed dose that enters the body.

39
Q

What is administered dose?

A

This is the quantity administered usually orally or by injection.

40
Q

What is total dose?

A

This is the sum of all individual doses.

41
Q

What is first test to be performed on a new chemical in Descriptive Animal Toxicity Tests?

A

Acute Lethality

42
Q

Daily Examination for Acute Lethality examines for?

A
  1. Morbidity
  2. Weight
  3. Lethargy – weariness, fatigue, laziness
  4. Food Consumption
  5. Behavior modification
43
Q

What type of volunteer are used in acute lethality?

A

Adult male and female animals are used only.

44
Q

What is the Draize Test?

A

This is an acute toxicity test for assessing the effects of chemicals, substances and mixtures in terms of their potential to cause eye irritancy or damage to the eye.

45
Q

What is the overall watching time for a lab animal after testing?

A

14 days.

46
Q

What is the second test done in animal toxicity test?

A

Skin and Eye Irritations.

47
Q

Why is Skin and Eye Irritations test done in Animal Toxicity Test?

A

Done due to the probability of skin and eye irritation occurring after acute exposure.

48
Q

What is Erythema?

A

Redness

49
Q

What is Eschar?

A

Scar

50
Q

What is Edema?

A

Swelling.

51
Q

What is the third test in animal toxicity Tets?

A

Sensitization

52
Q

What is sensitization?

A

an inflammatory immune response that manifests only in some people and then frequently after repeated exposure. This is is a warning mechanism designed to protect the body from a strong allergic reaction.

53
Q

What is irritation?

A

a temporary damage to epidermal cells caused by direct contact with a substance, including ingredients in cosmetics and personal care products.

54
Q

What is Toxicodendron Radicans?

A

Poison Ivy

55
Q

Why do we do Sub-acute test?

A

Done to analyse effects of chemicals after short period exposure, through repeat administrations.

56
Q

Why do we do a sub chronic test?

A
  1. determining the organ(s) affected as a result of longer exposure.
  2. determine NOEL (NOAEL) and LOAEL which help to find the reference dose.
57
Q

What is test 4 & 5, respectively in animal toxicity tests?

A

Sub-acute and sub-chronic

58
Q

What does NOAEL mean?

A

No-observed-adverse-effect level

59
Q

What is NOAEL?

A

the largest dose at which no effects are observed or identified

60
Q

What is LOAEL?

A

The lowest tested dose of a substance that has been reported to cause harmful (adverse) health effects on people or animals.

61
Q

What are the volunteer in the sub chronic stage?

A

Makes use of two species: Rats and Dogs

62
Q

How many doses are applied in subchronic stage?

A

Three doses are applied

63
Q

What is Reference Dose (RfD)?

A

This is an oral dose of a toxic substance that is made acceptable by the Environmental Protection Agency (EPA).

64
Q

What is sixth stage in animal toxicity tests?

A

Chronic

65
Q

What is the purpose of Chronic sixth stage in animal toxicity stage?

A

It aids in analysing the overall toxic effects of substances while taking into consideration carcinogenic potential of the substance.

66
Q

What are factors for choosing chronic exposure testing period?

A
  1. The intended use of the substance is for a short while. Chronic exposure of 6 months is acceptable. E.g. Antibiotic
  2. Exposure to the substance is intended for life time exposure in human. Chronic exposure testing of 2 years is acceptable. Food additives
67
Q

What is MTD acronym ?

A

Maximum Tolerable Dose

68
Q

What is MTD?

A

The highest dose of a drug or treatment that does not cause unacceptable side effects.

69
Q

What is the seventh stage of animal toxicity testing?

A

Developmental and Reproductive Toxicity

70
Q

What is Developmental Toxicity Testing?

A

The study of adverse effects on an organism from before conception to puberty due to exposure to toxins/toxicants.

71
Q

What is teratology?

A

A sub study of organism developmental analysis, it is concerned with defects that occur between conception and birth.

72
Q

What is Embryolethality?

A

failure to convince, spontaneous abortion or still birth.

73
Q

What is Embryotoxicity?

A

growth retardation or delayed growth of specific organ systems.

74
Q

What is teratogenicity?

A

irreversible conditions that leave permanent birth defects in live offspring.

75
Q

How many segments are there development and reproductive toxicity?

A

There are 3 segments.

76
Q

What are the 3 segments in development and reproductive toxicity?

A

Segments I: Fertility and Reproductive Performance
Segments II: Teratogenicity Toxicity
Segments III: Perinatal and Prenatal

77
Q

What is the purpose of segement I in development and reproductive toxicity?

A

Looks at the adverse effects induced by toxins and toxicants on fertility and reproduction

78
Q

When are teratogenicity toxicity most potent?

A

Teratogens are most potent in the 1st trimester

79
Q

What occurs in segment II in development and reproductive toxicity?

A

Foetuses are removed and the live, dead are taken into account

80
Q

What are the groups of live foetuses?

A
  1. Ones on which skeletal abnormalities are analysed
  2. Ones on which tissue abnormalities are analysed
81
Q

What is the purpose of segment III in development and reproductive toxicity?

A

The substance of interest is administered to rats on the 15th day of gestration throughout dilivery and lactation

82
Q

What effects are analysed in the first three weeks of segement III?

A
  1. Weight
  2. Survival
  3. Growth
83
Q

What is the eigth test in animal toxicity test?

A

Mutagenicity

84
Q

What is Mutagenicity?

A

Mutagenicity refers to the changes influenced by substances to genetic material of a cell, which are transmitted through cell division.

85
Q

What are the types of mutagenicity?

A
  1. Germanic/Germline Mutations
  2. Somatic Mutations
86
Q

What is the process of mutagenesis?

A

is a process by which the genetic information of an organism is changed by the production of a mutation. It may occur spontaneously in nature, or as a result of exposure to mutagens.

87
Q

What are Germanic/Germline Mutations?

A

Mutations that occur in the germ (sex) cells of living organisms.

88
Q

What are the consequences of Germanic Mutations?

A
  1. Early death or abnormality during embryonic
    development
  2. Early death or abnormality during developmental stages of organism
89
Q

What are the consequences of Somatic Mutations?

A
  1. Cell death
  2. Transmission of mutations to other like cells causing future abnormalities