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BMP-2 and BMP-4 are known to be involved in the early events which specify the cardiac lineage. Their later patterns of expression in the developing mouse and chick heart, in the myocardium overlying the atrioventricular canal (AV) and outflow tract (OFT) cushions, also suggest that they may play a role in valvoseptal development. In this study, we have used a recombinant retrovirus expressing noggin to inhibit the function of BMP-2/4 in the developing chick heart. This procedure resulted in abnormal development of the OFT and the ventricular septum. A spectrum of abnormalities was seen ranging from common arterial trunk to double outlet right ventricle. In hearts infected with noggin virus, where the neural crest cells have been labelled, the results show that BMP-2/4 function is required for the migration of neural crest cells into the developing OFT to form the aortopulmonary septum. Prior to septation, misexpression of noggin also leads to a decrease in the number of proliferating mesenchymal cells within the proximal cushions of the outflow tract. These results suggest that BMP-2/4 function may mediate several key events during cardiac development. Key Words: bone morphogenetic proteins; noggin; neural crest; outflow tract; morphogenesis.

Teeth have been missing from birds (Aves) for at least 60 million years. However, in the chick oral cavity a rudiment forms that resembles the lamina stage of the mammalian molar tooth germ. We have addressed the molecular basis for this secondary loss of tooth formation in Aves by analyzing in chick embryos the status of molecular pathways known to regulate mouse tooth development. Similar to the mouse dental lamina, expression of Fgf8, Pitx2, Barx1, and Pax9 defines a potential chick odontogenic region. However, the expression of three molecules involved in tooth initiation, Bmp4, Msx1, and Msx2, are absent from the presumptive chick dental lamina. In chick mandibles, exogenous bone morphogenetic protein (BMP) induces Msx expression and together with fibroblast growth factor promotes the development of Sonic hedgehog expressing epithelial structures. Distinct epithelial appendages also were induced when chick mandibular epithelium was recombined with a tissue source of BMPs and fibroblast growth factors, chick skin mesenchyme. These results show that, although latent, the early signaling pathways involved in odontogenesis remain inducible in Aves and suggest that loss of odontogenic Bmp4 expression may be responsible for the early arrest of tooth development in living birds.

Special considerations for the management of adult congenital heart disease include pregnancy-related cardiovascular disease, pulmonary arterial hypertension, and arrhythmias. Improvements in the treatment of congenital heart disease mean that more women with congenital heart disease are reaching childbearing age. In BC the Cardiac Obstetrics clinic at St. Paul's Hospital provides coordinated care for pregnant women with cardiac conditions. The clinic also offers preconception counseling so that couples can make informed choices about pregnancy. Another service based at St. Paul's Hospital, the Pacific Adult Congenital Heart clinic, helps manage patients with pulmonary arterial hypertension, a progressive condition affecting around 10% of adult congenital heart disease patients. Agents used to treat pulmonary arterial hypertension include endothelin receptor antagonists and phosphodiesterase type 5 inhibitors. The Pacific Adult Congenital Heart clinic also manages patients with a significant arrhythmia, often the first manifestation of deterioration in complex congenital heart disease. Complications that can result from arrhythmias include heart failure, thromboembolism, and sudden cardiac death. A range of complementary imaging modalities aid in the management of all these conditions by enabling the assessment of ventricular and valvular function (echocardiography and magnetic resonance imaging), quantification of right ventricular volume (multidetector computed tomography), and exclusion of coronary stenosis (coronary CT angiography). [ABSTRACT FROM AUTHOR]