Cardiac hypertrophy and dilatation can result from stimulation of signal transduction pathways mediated by heterotrimeric G proteins, especially G q , whose ␣ subunit activates phospholipase C␤ (PLC␤). We now report that transient, modest expression of a hemagglutinin (HA) epitope-tagged, constitutively active mutant of the G q ␣ subunit (HA␣* q ) in hearts of transgenic mice is sufficient to induce cardiac hypertrophy and dilatation that continue to progress after the initiating stimulus becomes undetectable. At 2 weeks, HA␣ * q protein is expressed at less than 50% of endogenous ␣ q͞11 , and the transgenic hearts are essentially normal morphologically. Although HA␣ * q protein declines at 4 weeks and is undetectable by 10 weeks, the animals develop cardiac hypertrophy and dilatation and die between 8 and 30 weeks in heart failure. As the pathology develops, endogenous ␣ q͞11 rises (2.9-fold in atria; 1.8-fold in ventricles). At 2 weeks, basal PLC activity is increased 9-to 10-fold in atria but not ventricles. By 10 weeks, it is elevated in both, presumably because of the rise in endogenous ␣ q͞11 . We conclude that the pathological changes initiated by early, transient HA␣ * q expression are maintained in part by compensatory changes in signal transduction and other pathways.

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Vascularized groin lymph node transfer (VGLNT) has been successfully used to treat lymphedema. However, lack of familiarity with the inguinal node anatomy and concerns regarding donor site morbidity have limited its widespread use. The purpose of this study was to use magnetic resonance angiography (MRA) to clarify the inguinal anatomy and provide a reliable method for identifying the location of the superficial transverse inguinal lymph nodes. In this study MRA was used to evaluate the superficial inguinal lymph nodes in 117 patients. Coordinates of lymph nodes were plotted relative to an axis from the anterior superior iliac spine (ASIS) to the pubic tubercle (PT). The nodes were also plotted relative to the superficial circumflex iliac vein (SCIV) and superficial inferior epigastric vein (SIEV). A total of 1,938 lymph nodes were identified. These lymph nodes were concentrated on one-third the distance from the PT toward the ASIS and 3 cm perpendicularly below this line. About 67% of the superficial inguinal nodes were located within the bifurcation of the SIEV and SCIV. The results from this study provide useful guidelines for locating lymph nodes targeted for VGLNT.