Increased nuclear sizes in senescent human diploid fibroblast cultures.

Measurement of nuclear size in cultured human diploid fibroblasts (WI38) reveals a shift to larger cell nuclei as afunction of in vitro passage. Examination of nuclear size distribution on the basis of replicative potential reveals that at all levels of in vitro passage, the rapidly replicating cell population have smaller nuclear sizes than comparable populations of slow or non-replicating cells. While the nuclear size distribution of the rapidly replicating cell population remains relatively constant, there is a marked shift in the nuclear size distribution of the slow or non-replicating cell population to larger sizes with increasing in vitro passage.