Rac1 promotes kidney collecting duct repair by mechanically coupling cell morphology to mitotic entry.

Prolonged obstruction of the ureter, which leads to injury of the kidney collecting ducts, results in permanent structural damage, while early reversal allows for repair. Cell structure is defined by the actin cytoskeleton, which is dynamically organized by small Rho guanosine triphosphatases (GTPases). In this study, we identified the Rho GTPase, Rac1, as a driver of postobstructive kidney collecting duct repair.

Abrupt aortic root dilation after the Ross procedure--is this a progressive phenomenon?

This study provides evidence of aortic root dilation in children, adolescents, and young adults who have undergone the Ross procedure. Several mechanisms are described.

Single versus dual chamber pacing in the young: noninvasive comparative evaluation of cardiac function.

The advantages of atrial synchrony over asynchronous ventricular pacing remain unclear in the young, chronically right ventricular (RV) - paced patient. This is in contrast to the older patient with inherent diastolic dysfunction who has been shown to benefit from atrial synchrony with dual chamber (DDD,R/VDD), over single chamber rate response (VVI,R) ventricular pacing. The goal of this study was to noninvasively assess cardiac function in a group of young, RV-paced patients before and after establishment of atrial synchrony.

Left ventricular dysfunction after long-term right ventricular apical pacing in the young.

Objectives: The goal of this study was to assess long-term global left ventricular (LV) function in patients paced from the right ventricular (RV) apex at a young age.

Background: Ventricular contraction asynchrony with short-term RV apical pacing has been associated with reduced LV pump function and relaxation. The long-term effect of RV apical pacing on global LV function in the young remains unknown.

Biventricular pacing as alternative therapy for dilated cardiomyopathy associated with congenital heart disease.

Biventricular, alternative, and multisite pacing are currently being explored to improve cardiac function among patients with medically refractory, end-stage dilated cardiomyopathies. Although, due to inherent myocardial abnormalities, patients with repaired congenital heart defects may be at a greater risk than others to develop heart failure, often requiring cardiac transplantation. The efficacy of biventricular pacing among these patients is unknown.