FIG. 2.

Immunohistochemical demonstration of apoptotic nuclei in sections of kidney cortical specimens of controls (A) and animals treated for 10 days with gentamicin at 10 (B) and 20 (C) mg/kg. Sections were treated for TdT-mediated labeling of fragmented DNA (TUNEL [19]). Positive nuclei were identified as shrunken, darkly stained bodies with either a condensed or a fragmented appearance (arrowheads). Labeling is also detected in small granules which probably originate from the disruption of an apoptotic nucleus (arrows). When these granules occurred in clusters, only one count was recorded in the quantitative analysis (Fig. 3). Bars, 20 μm.