Chapter 8: Cell Survival Curves & Mechanisms of Cell Killing Flashcards
A ________ measures the number of living cells. It is _______ and takes _________.
viability assay
quick
24-72 hours
A __________ measures the number of clones produced by seeded cells. It is ________ and takes _________. It is __________.
clonogenic assay
more difficult to measure
1-2 weeks
more relevant to clinical treatment outcome
A cell survival curve describes the relationship between ___________ and ___________.
radiation dose
proportion of cells that survive
For differentiated cells that do not proliferate, death is ___________.
loss of a specific function
For proliferating cells, death is __________.
loss of reproductive integrity.
In radiobiology a cell is dead if it has lost the capacity to _________ and produce _____________.
divide indefinitely
large number of progeny
A __________ retains its reproductive integrity and is able to proliferate indefinitely to produce a colony.
clonogenic cell
For tumors, cells are dead if they are ________ and cause __________.
unable to divide
further growth/spread of malignancy
__________ is the dominant mechanism following irradiation for most cells.
Mitotic death
A dose of _______ is needed to destroy cell function in non-proliferating systems. The mean lethal dose for loss of proliferative capacity is __________.
100 Gy
2 Gy
To produce a cell survival curve, a ________ is necessary.
clonogenic assay
Plating efficiency is the percentage of cells seeded that _________. The formula is _________. This is typically calculated on the _________ plate.
grow into colonies
[number of colonies counted/number of cells seeded]x100%
control
Dead cells that have not divided and show evidence of nuclear deterioration go through ____________.
apoptotic death
The surviving fraction is given by: ________.
= Colonies counted / [Cells seeded x (PE/100)]
For survival curves of mammalian cells dose is plotted on ________ and surviving fraction on _________.
linear scale
logarithmic scale
The _________ model of cell survival is based on the concept that a number of critical targets have to be inactivated for cells to be killed.
target theory
A single-hit, single-target survival curve is a ___________ line on a ___________ plot. This curve applies to inactivation of _______ and _______, and to ___________, __________, _________.
straight
semilogarithmic plot
viruses
bacteria
radiosensitive mammalian cells
response to very low dose rates
response to high LET radiation
When a dose gives an average of 1 hit/target, the survival fraction is ___________.
0.37
_________ is programmed cell death
apoptosis
__________ is from acute cellular injury and culminates in the release of intracellular components.
necrosis
________ is when cells undergo rapid proliferation causing telomeres of their chromosomes to become a lot shorter. eventually cell growth decelerates and cells enter permanent cell-cycle arrest.
senescence
________ is mechanism where long-lived proteins and organelles are directed to and degraded within lysosomes.
Autophagy
_________ is caused by not producing proper chromosome segregation and cell division, but results in cell death or formation of nonviable cells.
mitotic cell death
Belgian scientist Christian de Duve won Nobel prize for discovery of __________.
lysosome
The lysosome _________ cellular contents which provides the cell with ________ and ________ for renewal.
digests
nutrients
building blocks
________ has major role in innate immune defense by effectively killing pathogens. Also an initiating branch of ________ immune response.
Phagocytosis
adaptive
Mitotic cell death is frequently followed by __________.
apoptosis
For gels with cells undergoing apoptosis it creates a _________ but for cells undergoing necrosis it creates a _________.
smear
Exchange type aberrations require ______ chromosome breaks.
2
At low doses the two breaks may result from ___________. Causes survival curve to be ________.
passage of single electron
linear
At high doses the two breaks may result from __________. Causes survival curve to be __________. Probability of interaction between the two breaks is proportional to __________.
two separate electrons
quadratic
square of dose
Mitotic death principally results from _____________. The associated cell survival curve is ______________.
exchange-type chromosome aberrations
curved in log-linear plot
Apoptotic death results from _________. The associated cell survival curve is _________.
unknown mechanisms
straight line on log-linear plot
The _________ is the induction of biologic effects in cells that are not directly traversed by a charged particle but are in proximity to cells that are. Typically done using ___________.
bystander effect
alpha particles
