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Toxi Lab > Micronucleus > Flashcards

Micronucleus Flashcards

1
Q

MICRONUCLEUS/MICRONUCLEI is also known as

A

Howell-Jolly bodies

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2
Q

Micronucleus/micronuclei or Howell-Jolly bodies is a _______________ that is ___________ from the main nucleus and
has originated from a chromosome or fragment of a
chromosome that ___________ to be included into one of the daughter
nuclei during cell division

A

DNA fragment; separated; fail

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3
Q

micronucleus/micronuclei or Howell-Jolly bodies: Chromosomal breakage or spindle damage during
___________/____________

A

metaphase/anaphase

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4
Q

T/F: If the cell is exposed to a genotoxic agent, there is spindle damage and can result in formation of
micronucleus

A

True

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5
Q

Micronucleus is viewed through a microscope by the

A

OIO (oil immersion objective)

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6
Q

Extranuclear biomarker of chromosomal damage

A

micronucleus/micronuclei or Howell-Jolly bodies

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7
Q

Typically round with as diameter of about 1/20 to 1/5 of the
erythrocytes.

A

micronucleus/micronuclei or Howell-Jolly bodies

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8
Q

Some are almost almond-shaped.

A

micronucleus/micronuclei or Howell-Jolly bodies

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9
Q

T/F: Micronucleus can also be caused by ionizing radiation, a physical
mutagen

A

True

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10
Q

double strand breakage or by DNA damage

A

Clastogens

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11
Q

Accentric chromosome fragments are formed which
initiates formation of micronucleus

A

Clastogens

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12
Q

damage to spindle

A

Aneugens

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13
Q

Whole chromosome is affected as a result of spindle
damage, which normally pulls chromosomes from the
center part of the cell during mitosis

A

Aneugens

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14
Q

T/F: Both (Aneugens and Clastogens) will result in the formation of micronucleus

A

True

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15
Q

T/F: A single micronucleus can result in proliferation, unless
the cell undergoes apoptosis

A

True

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16
Q

Point mutations or deletions/insertions that affect single
or blocks of genes

A

Gene mutation

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17
Q

Structural chromosome changes

A

Clastrogenicity

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18
Q

The occurrence of one or more extra or missing
chromosomes, leading to unbalanced chromosome
complement

A

Aneuploidy

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19
Q

Micronucleus test is in vivo or in vitro?

A

In vivo

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20
Q

In vivo toxicity study developed by Schmid and coworkers in
1975.

A

Micronucleus test

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21
Q

Micronucleus test is used to screen compounds for genotoxicity caused by
________ (chromosome-breaking) or ___________ (loss of
whole chromosome activity) by detecting micronuclei.

A

clastogens; aneugens

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22
Q

Micronucleus test is used to check if the chemical can cause DNA damage,
specifically at _

A

chromosomal level

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23
Q

Agents used are genotoxic or mutagenic that cause DNA
damage

A

Micronucleus test

24
Q

Alklyating agents used for cancer treatment such as __________ and __________ — affecting DNA mutations of
cancer cells and can also affect DNA of normal cells

A

vincristine and vinblastine

25
Q

**Micronucleus test:
**
Genetic material replicates and divides ________ between two
daughter cells

A

equally

26
Q

Principle of Micronucleus test:

When a bone marrow erythroblast develops into a
polychromatic erythrocyte, the main nucleus is ______________;
micronuclei that have been formed may remain behind in the
otherwise _____________ cytoplasm

A

extruded; enucleated

27
Q

Micronuclei are found in a variety of different marrow
cells such as

A

myeloblast, myelocytes, erythroblasts,
erythrocytes

28
Q

Majority of micronuclei are found in

A

polychromatic (immature)
erythrocytes

29
Q

Giemsa stain color for immature

A

Blue

30
Q

Giemsa stain color for mature

A

Pinkish or orange

31
Q

Test animals for micronucleus test

A

male or female rodents (Swiss mice or rats)

32
Q

T/F: Male and female rodents exhibit the same mechanism of blood production within the bone marrow as humans.

A

True

33
Q

Test animals are supposed to be at __________ weeks old at the start of treatment

A

6-10 weeks old

34
Q

Weight variation of test animls

A

should not exceed ± 20% of mean
weight

35
Q

Three dose levels

A

1/8, 1/4, 1/2 of the LD50

36
Q

T/F: solids must be dissolved in appropriate solvent first

A

True

37
Q

Solvents used

A

water, NSS, dimethylsulfoxide (DMSO)

38
Q

T/F: Liquids may be dosed directly or diluted prior to dosing

A

True

39
Q

Substances that produce a detectable
increase in micronucleus frequency

A

Positive Control

40
Q

Mitomycin-C (anticancer/antineoplastic)

A

Positive control

41
Q

dimethylnitrosamine (alkylating agents),

A

Positive control

42
Q

cyclophosphamide

A

Positive control

43
Q

triethylenemelamine

A

Positive control

44
Q

ethylmethanesulfonate

A

Positive control

45
Q

Solvent or vehicle used in administering
the test chemical

A

Negative control

46
Q

Ethyl methansulphonate

A

Negative control

47
Q

Methyl methanesulphonate

A

Negative control

48
Q

Ethyl nitrosourea

A

Negative control

49
Q

Mitomycin

A

Negative control

50
Q

Cyclophosphamide

A

Negative control

51
Q

Triethylenemelamine

A

Negative control

52
Q

Colchicine

A

Negative control

53
Q

Route of administration and frequency

A

Administered IP, IM, PO twice

54
Q

Drugs mus be given ________ hours before and _________ hours before the animals are sacrificed

A

30 hours, 6 hours

55
Q

_____ and _______ have faster exposure

A

IP and IM

Toxi Lab (6 decks)

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