Satellite cells and regenerative fibres in human cremaster muscle. (A,B) Percentage of MYH3 (embryonic myosin isoform)-expressing fibres detected by immunofluorescence (green), surrounded by LAMININ (red). Arrows in (A) show regenerative fibres and the graph (B) shows regenerative fibres as a percentage of total fibres, as quantified in three independent biopsies. The blue line represents the median value of the data. (C,D) Immunofluorescence detection of PAX7+ satellite cells (green) located in their niche between two LAMININ positive layers (red). The arrow in (C) points to a satellite cell. (D) Percentage of PAX7 positive nuclei as quantified in three independent biopsies. The blue line represents the median value of the data. Nuclei were counterstained with Hoechst 33258 (blue). Scale bars, 100 μm.