Within these counting frames, the number of gold particles associated with plasma membranes, N g, and the number of test points hitting cell profiles, Σ Pcell2, were counted.
"This suggests there may be a sharp window during which you want to hit cells with a second drug," said Chen.
The results suggest that low dose radiation may be more dangerous than has been estimated from calculations based only on directly hit cells.
In order to simulate chemotherapy-induced cell death, lethally hit cells are assumed to enter a rudimentary cell cycle leading to apoptotic death.
The numbers of cells hit by the drug are computed through the utilization of the cell kill ratio (CKR) parameter (CKR = 1-cell survival fraction), defined as the percentage of lethally hit cells after each drug administration.
Genetic/epigenetic changes occur not only in cells hit by the ionizing particles but also in non-irradiated cells that are neighbouring directly hit cells.
Yet an alternative to the cell of origin hypothesis cannot be excluded; it is conceivable that the tumorigenic event hits cells at any position in the hierarchy and causes acquisition of luminal progenitor characteristics.
The first wave, which affects only a very small subset of identified thiol-containing proteins (<10%), hit cells cultivated in standard media within 24 48 hr after reaching exponential growth.
The first wave to hit cell phones targets the Symbian operating system.
