Figure 7.

Cardiac malformations in Ptdsr^-/- embryos: analysis using histology Embryos analyzed by MRI (Figure 3) were sectioned transversely and stained with hematoxylin and eosin. (a–c) Serial caudal to cranial sections of the wild-type embryo showing normal cardiac and vascular anatomy. The left and right ventricles (lv, rv) are separated by the interventricular septum (ivs). The ascending aorta (a-ao) arises from the left ventricle, continues on as the aortic arch (ao-a), which joins the descending aorta (d-ao). The pulmonary artery (pa) arises from the right ventricle via the pulmonary valve (pv) and continues as the arterial duct (ad), which joins the descending aorta. The left and right atria (la, ra), trachea (tr), right main bronchus (rmb) and esophagus (es) are indicated. (d) Section through embryo 33 indicating the ventricular septal defect (VSD). (e, f) Sections through embryo 55 showing that both aorta and pulmonary artery arise from the right ventricle (double outlet right ventricle), and that the arterial duct of the pulmonary artery is narrow in comparison to the aorta – indicating pulmonary artery hypoplasia. The aortic valve (aov) is indicated. (g–i) Serial caudal to cranial sections through embryo 35 showing a VSD, aorta arising from the right ventricle (double outlet right ventricle), and a severely narrowed arterial duct. Scale bars = 500 μm; axes: r – right; l – left; d – dorsal; v – ventral. Individual embryos are indicated by number.