An SNF2 factor involved in mammalian development and cellular proliferation.

Members of the SNF2 (Sucrose Non-Fermenter) family of chromatin-remodeling proteins function in processes ranging from DNA repair to transcription to methylation. Using differential display, we recently identified a novel member of the SNF2 family that is highly expressed at the mRNA level in proliferating cells and is down-regulated during apoptosis. We have named this gene PASG (Proliferation-Associated SNF2-like Gene). Northern blot analysis of adult mouse tissues shows PASG to be highly expressed in proliferating organs such as thymus, bone marrow, and testis and absent from nonproliferative tissues such as brain and heart. In situ hybridization analysis of mouse embryos shows that PASG is differentially expressed during development, with highest expression in developing face, limbs, skeletal muscle, heart, and tail. In vitro, PASG expression correlates with a shift from a quiescent to a proliferative state. Mice null for PASG (also known as LSH or Hells) are reported to die perinatally, although the mechanism for lethality is unclear (Geiman and Muegge, 2000). To test the hypothesis that PASG functions in cell proliferation, we compared 5-bromodeoxyuridine (BrdU) incorporation in C33A cells transiently transfected with PASG versus empty vector and found that PASG transfected cells showed a significant decrease in the amount of BrdU incorporation. These findings suggest that PASG plays a role in cell proliferation and may function in the development of multiple cell lineages during murine embryogenesis.

Thrombotic occlusion of the main stem of the left coronary artery in a neonate.

Thrombotic coronary arterial occlusion, and myocardial infarction, are rare in the newborn. We report such a happening presenting shortly after birth with cardiogenic shock, no left ventricular output and a systemic circulation dependent on flow from a patent arterial duct.

Acute pulmonary embolism in a neonate: precipitation during cardiac catheterization and successful treatment.

This report illustrates the rare occurrence of a pulmonary embolus in a neonate during cardiac catheterization. The patient was a term newborn who underwent repair of obstructed infradiaphragmatic total anomalous pulmonary venous connection. Postoperative risk factors for pulmonary embolism included severe pulmonary hypertension unresponsive to nitric oxide therapy, an indwelling venous catheter, and young age. Successful management was achieved by initial mechanical fragmentation with streptokinase infusion and monitoring by serial lung perfusion scans.

Pulmonary venous flow Doppler velocities in children.

We report the results of a prospective study of pulmonary venous (PV) flow Doppler velocities in 68 normal children. We sought to establish the normal PV flow velocities in the broad pediatric population, compare these velocities to heart rate and age. In normal children, there is a wide range of PV flow velocities, most of which correlate with age and heart rate. However, the PV flow velocities and their durations do not distinguish the age groups. The peak velocity of systolic forward flow and atrial reversal flow in the pulmonary vein were independent of heart rate. The PV flow peak systolic velocity showed a weak correlation with the velocity of the mitral inflow early wave. However, the velocity of atrial reversal flow showed no correlation with the mitral inflow A velocity (late wave), which is generated by the same force of atrial contraction.