Chromatin texture analysis in living cells

In recent years, there has been an increasing interest in applications of f luorescence measurements to studies on many physiological mechanisms in liv ing cells. However, few studies have taken advantage of DNA quantification by fluorometry for dynamic assessment of chromatin organization. This type of approach involves both optimal conditions for DNA staining and the use o f image cytometry. In this context, this report describes the application o f an internal grey-level segmentation method for the assessment of real tim e modifications of chromatin organization in living cells. These developmen ts are based on a specific, stoichiometric method for nuclear DNA content m easurement. Preliminary data obtained from Hela cells suggests the possibil ity of following variations of nuclear texture (heterogeneity, granularity, condensation, radial distribution) related to the cell cycle progression o f cells that are maintained alive.