(Midterms) Specific Cellular Effects Flashcards
1
Q
Specific cellular effects of radiation
A
- Cellular Effects
- Somatic Effects
- Local Tissue Damage
- Cytogenic Effects
CS LoCyte
2
Q
IR adversely affects primarily by —
A
transferring energy to nucleus
3
Q
XR/ Gamma Irradiation of abt 1000 Gy (100,000 rad) in a period of seconds or few minutes
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Instant Death
4
Q
Cause: Gross disruption of cellular form and structure
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Instant Death
5
Q
Cause: Severe changes in chemical machinery
A
Instant Death
6
Q
Result: Breakage of cell’s DNA macromolecule
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Instant Death
7
Q
Result: Cellular Proteins Coagulate
A
Instant Death
8
Q
An ionizing radn dose of 1 to 10 Gyt
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Reproductive Death
9
Q
Result: Permanent loss of ability to procreate (Termination of cells’ reproductive abilities)
A
Reproductive Death
10
Q
Reproductive Death Exclusion
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Transmission of damage to future generation of cells
11
Q
Non-mitotic, non-dividing type of cell death
A
Apoptosis
12
Q
When cells die without attempting division during the interphase portion of the cell ife cycle
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Apoptosis (Programmed cell death)
13
Q
Apoptosis (Programmed cell death) is formerly known as —
A
Interphase death
14
Q
Spontaneous in both normal tissue and in tumors
A
Apoptosis (Programmed cell death)
15
Q
Apoptosis Research
A
A new type of RadThera may involve activation of the genes that regulate apoptosis so that the occurrence of apoptosis becomes much more likely after Irradiation in a tumor
16
Q
More sensitive cells require — dose to induce apoptosis
Ex. bone marrows, platelets
A
smaller
17
Q
Apoptosis may be required of radn dose of —
A
several thousands of centigray
18
Q
Occurence: Human beings (embryo and adult)
A
Mitotic Death
19
Q
Occurence: Vertebrate animals
A
Mitotic Death
20
Q
Occurence: Amphibians
A
Mitotic Death
21
Q
Radiation dose required to induce mitotic death is — than the dose needed to produce apoptosis in
slow dividing cells/non dividing cells.
A
less
22
Q
Failure of cell to start dividing on time
A
Mitotic Delay
23
Q
Mitotic delay
Cause is unknown but possible reasons for delay are:
A
- Alterations of a chemical involved in mitosis
- Proteins required for cell divisions are not synthesized
- Change in rate of DNA after irradiation
24
Q
When the cell dies after one or more divisions
A
Mitotic Delay
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Dose: Less than 0.01 Gy needed to produce apoptosis in slowly dividing cells or non-dividing cells
Mitotic Delay
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After a mitotic delay, the cell may resume its ---
normal mitotic function
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Even small doses of radiation can cause this type of cell death
Mitotic Delay
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Effect of IR in Mitotic Delay
Retardation, Permanent inhibition
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If repair enzymes are able to fix damage, the cell can recover and continue to function
Interference of Function
30
Interference of function may be:
1. Permanent
2. Temporary
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When ionizing radn interacts with a DNA macromolecule
Chromosome Breakage
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These breaks may occur in one or both strands (sugar phosphate chains) of the FNA ladder like structure
Chromosome Breakage
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If cells are irradiated during mitosis and chromosome breakage occurs, --- will be evident in future mitotic cycles
permanent chromosome abnormalities
34
Manifestations of Cell's Nucleus Damage
1. Instant Death
2. Reproductive death
3. Apoptosis
4. Mitotic death
5. Mitotic delay
6. Interference of function
7. Chromosome breakage
CRAMIMI
35
Basis if early/ late somatic effect
1. Quantity of IR to which the subject is exposed
2. Ability of IR to cause ionization of a human tissue
3. Amount of body area exposed
4. Specific body part exposed
36
Early deterministic somatic Effects are aka
Acute somatic effects
37
Cell killed and directly related to the dose received
(Severity of effect is dose related)
Early deterministic somatic Effects
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Appears w/in minutes, hrs, days, or wks of the time of radn
Early deterministic somatic Effects
39
Acute Radn Syndrome is referred to as ---
Radn Sickness
40
After whole-body reception of large doses of IR delivered over a short period of time
ARS
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Dose-related syndromes as part of the total-body syndrome
1. Hematopoetic syndrome
2. GI syndrome
3. Cerebrovascular syndrome
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First people to experience ARS
1. Atomic bomb survivors of Hiroshima and Nagasaki
2. Martial islanders during the aromic bomb testing in 1954
3. Victims during chernobyl accident
4. Pts who underwent RadThera
43
Hematopoetic syndrome is aka
Bone Marrow Syndrome
44
Dose levels: may damage cells in other organs systems and cause the affected organ or organ system to fail
Hematopoietic Syndrome
45
Determine the possibility of recovery:
❖ Actual dose of radiation received
❖ Irradiated person's general state of health at the time of irradiation
Hematopoietic Syndrome
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Before death: Hemorrhage and dehydration
Hematopoietic Syndrome
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Death: Because of infection, electrolyte imbalance and dehydration
Hematopoietic Syndrome
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Hematopoietic system composition
Bone marrow
Circulating blood
Lymphoid tissue
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Lymphoid tissues composition
Lymph nodes
Spleen
Thymus
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With this system, the principal effect of radiation is a depressed number of blood cells in the peripheral circulation
Hemopoietic System
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All cells of the hemopoietic system apparently develop from this single type of stem cell
Pluripotential stem cell
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Products of bone marrow stem cells (Principal types of blood cells; develop from a single stem cell)
Lymphocytes
Granulocytes
Thrombocytres
Erythrocytes
(LET G!)
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These cell lines develop at different rates in the bone marrow and are released to the (1) as (2).
1. peripheral blood
2. mature cells
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Spend abt 8-10 days in the BM
Developing Granulocytes and erythrocytes
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Have a lifetime of approx 5 days in the BM
Thrombocytes
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Produced over varying times and have varying lifetimes in the peripheral blood
Lymphocytes
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In the peripheral blood, these have a lifetime of only a couple of days
Granulocytes
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Have a lifetime of approx 1 week in the peripheral blood
Thrombocytes
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Have a lifetime of nearly 4 months in the peripheral blood
Erythrocytes
60
Example of a cell renewal system
Hemopoietic system
61
After exposure, the first cells to become affected are
the (1). These cells are reduced in number called (2) within minutes or hours after exposure, and they are very slow to recover
1. lymphocytes
2. lymphopenia
62
Most radiosensitive cells in the body
Lymphocytes
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(1) experience a rapid rise in number called (2), followed first by a rapid decrease and
then a slower decrease in number called (3)
1. Granulocytes
2. granulocytosis
3. granulocytopenia
64
If radn dose is moderate, then an abortive rise in granulocyte count may occur (1) after irradiation.
Minimum granulocyte levels are reached approximately (2) after irradiation.
Recovery, if it is to occur, takes approximately (3)
1. 15 to 20 days
2. 30 days
3. 2 months
65
The depletion of (1) after
irradiation develops more slowly, again because of the
longer time required for the more sensitive precursor
cells to reach maturity
1. platelets (thrombocytopenia)
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Thrombocytes reach a minimum in about (1) and recover in approximately (2), similar to the response of granulocytes
1. 30 days
2. 2 months
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Less sensitive than the other blood cells, apparently because of their very long lifetime in the peripheral blood.
Erythrocytes
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69
A few hours after the dose required to cause the gastrointestinal syndrome has been received, the prodromal stage occurs.
Gastrointestinal Syndrome
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Determines the organ/s potential for recovery.
Amount of functional damage sustained
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Lethal Doses (4)
LD 50/60 (humans)
LD 50/30 (old version)
LD 10/30
LD 100/60
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Pig LD
2.5 Gyt
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Humans LD
3.5 Gyt
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Cockroach LD
100Gyt
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Research:
Repeated radiation injuries have a (1). A percentage approx (2) of radn induced damage is irreparable , whereas the remaining (3) may be repaired over time
1. cumulative effect
2. 10%
3. 90%
76
Occurence: Months or yrs after exposure
Late Somatic Effects
77
Late Somatic Effects may result from
1. Previor whole or partial-body acute exposure
2. Previous high radn doses
3. Long-term low-level doses sustained over several years
78
These late effects can be directly related to the dose received
Late Deterministic Effect
79
Such slowly developing changes tot the body from rand expo received
Late Deterministic Effect
80
Late response sin the body to radn exposure that does not have a threshold
Let stochastic effect
81
Occur in an arbitrary or probabilistic manner, and have a severity that doesn't depend on dose
Let stochastic effect
82
Effects of radn on the embryo-fetus in utero that depend on fetal stage of devt and the radn dose received
Teratogenic effect
83
First one to advocate for radn protection
William Herbert Rollins (Boston Dentist)
84
Most radiosenstitive layer of skin
Basal cell layer
85
Responses to doses as low as 100mgt have been observed
Effect on Gonads
86
Dose needed to produce temporary (1) and permanent (2) sterility to a testes
1. 2Gy that'll last 12 months
2. 5Gy
87
Radn effects depend on age
Ovaries
88
Irradiation of ovaries at:
1. Early life- reduces their size (atrophy) through germ cell death
2. After puberty causes suppression a delay of menstruation (0.1 Gy)
89
Irradiation of approximately 100 mGyt (10 rad)
Testes
90
Testes
Patient should refrain from procreation for (1) until all cells that were in the (2) and (3) stages at the time of irradiation have matured and disappeared.
1. 2-4 months
2. spermatogonia
3. post-spermatogonia
91
Study of the genetic cells particularly cell chromosomes
Cytogenic effect
92
Karyotypes are aka
Chromosomal map
93
Karyotypes: Done in ---
Cytogenic analysis of chromosomes
94
Karyotypes consist of a photograph or (1), that is taken of the human cell nucleus during (2), when each chromosome can be individually demonstrated
1. photomicrograph
2. metaphase
95
Radiation-induced chromosome aberrations follow a --- relationship
nonthreshold dose-response relationship
