Fig. 6. Histological analysis of neonatal and embryonic Carp-Lbh transgenic hearts. (A-F) Frontal Hematoxylin and Eosin-stained sections of postnatal day 0 (P0) wild-type (wt) and transgenic (Tg) hearts. (A,B) Sections of entire hearts at level of pulmonary valves (pv) showing ventricular hypertrophy (double headed arrow) and dilation of the right atria (ra) in the Tg (B). (C,D) Close-up of the right ventricular outflow tract (rvot) below the pv, showing an obstruction of the pulmonary infundibulum in Tg mice (D, arrow) with excessive mesenchymal valve tissue and myocardial cells (# and arrowhead, respectively, in inset). (E,F) Close-up of the atrial septae. Note the patent foramen ovale in the Tg (asterisk). (G-L) Transverse Hematoxylin and Eosin-stained sections of E13 wt and hemizigous Carp-Lbh Tg hearts. Ectopic OFT valve formation (pound sign) in the right ventricle (rv), left ventricular (lv) hyperplasia (insets), levocardia (G,H), and a VSD (asterisk) are present in the Tg (I,J). (K,L) Sections at the level of the great arteries. Arrowhead indicates double right outlet ventricle (DORV) in the Tg heart. ao, aorta; aov, aortic valve; la, left atrium; lv, left ventricle; os, ostium secundum; pa, pulmonary artery; sp, septum primum.