Figure 6.

Histological sections of B^ΔΙ/B^– and B⁺/B^ΔΙ mouse hearts. (a) Four selected serial sections, anterior to posterior (clockwise from upper left), demonstrating the defect (arrowheads) in the membranous region of the ventricular septum in a P0 B^ΔΙ/B^– mouse heart. Ao, aorta; IVS, interventricular septum; LA, left atrium; LV, left ventricle; RV, right ventricle. H&E stain. Bar, 200 μm. (b) Normal cardiac histology in a B⁺/B^ΔΙ mouse (left) and area of myocyte disarray and hyperchromatic nuclei in a B^ΔΙ/B^– mouse (right). (c) Hypertrophied myocytes from a P24 B^ΔΙ/B^– mouse (right) and myocytes from a B⁺/B^ΔΙ littermate (left). H&E stain. Bar, 20 μm.