The Relationship between Apoptosis and Keratinization in Human Epidermis.

Extinction of Organelles in Differentiating Epidermis.

“…As described in the previous section, the nuclei in the cells of s. spinosum showed no conspicuous apoptotic structures, while the results suggest that they began to undergo the DNA fragmentation. It confirms the results reported earlier [29]. We speculate that some cells in s. germinativum preparing to form hair follicles may undergo DNA fragmentation, since internal and external root sheath cells or their progenitors were stained distinctly (Fig.…”

“…It is known that the degeneration of nuclei is accompanied by DNA fragmentation [25,29,45]. Although morphological similarity to apoptotic cells has been pointed out to be one of the features of differentiating keratinocytes [31,43,50], we have studied the structure of nuclei and cytoplasm in detail during the terminal differentiation of fetal and neonatal keratinocytes, and have shown that the programmed cell death (PCD) in these cells occurs in a keratinocytespecific manner as well as displaying apoptotic aspects.…”

Evaluation of cell death and proliferation in psoriatic epidermis

“…Our previous study [2] of normal epidermis using the TUNEL/TEM method supported this hypothesis and clearly showed a marked increase in the number of free 3 0 -OH ends in the condensed chromatin of granular cell nuclei in the normal epidermis, whereas apoptotic characteristics, such as reduced cell volume, membrane blebbing and apoptotic bodies were not detected in any layer of the psoriatic epidermis. However, Gandarillas et al [15] reported that keratinocyte terminal differentiation is considerably different from apoptosis in the following respects.…”

“…Details of the TUNEL/TEM procedure have been described elsewhere [2,18,19] and were fundamentally similar to the above-mentioned TUNEL method, except for the use of floating nickel grids with ultrathin sections on serial reagent drops and immunogold particles in place of immunoperoxidase. The ultrathin sections subjected to the TUNEL/TEM method were stained with uranyl acetate and lead citrate, and were observed under an electron microscope (H-7100, Hitachi Ltd., Tokyo, Japan).…”

“…It was reported that granular cell nuclei in the human epidermis contain a larger amount of fragmented DNA than basal and spinous cell nuclei, and granulosa cells undergo a type of apoptosis [2].…”