Myocardial interstitial edema forms as a result of several disease states and clinical interventions. Acute myocardial interstitial edema is associated with compromised systolic and diastolic cardiac function and increased stiffness of the left ventricular chamber. Formation of chronic myocardial interstitial edema results in deposition of interstitial collagen, which causes interstitial fibrosis. To assess the effect of myocardial interstitial edema on the mechanical properties of the left ventricle and the myocardial interstitium, we induced acute and chronic interstitial edema in dogs. Acute myocardial edema was generated by coronary sinus pressure elevation, while chronic myocardial edema was generated by chronic pulmonary artery banding. The pressure-volume relationships of the left ventricular myocardial interstitium and left ventricular chamber for control animals were compared with acutely and chronically edematous animals. Collagen content of nonedematous and chronically edematous animals was also compared. Generating acute myocardial interstitial edema resulted in decreased left ventricular chamber compliance compared with nonedematous animals. With chronic edema, the primary form of collagen changed from type I to III. Left ventricular chamber compliance in animals made chronically edematous was significantly higher than nonedematous animals. The change in primary collagen type secondary to chronic left ventricular myocardial interstitial edema provides direct evidence for structural remodeling. The resulting functional adaptation allows the chronically edematous heart to maintain left ventricular chamber compliance when challenged with acute edema, thus preserving cardiac function over a wide range of interstitial fluid pressures.

Although the Boyer Commission (1998) lamented the lack of research opportunities for all undergraduates at research-extensive universities, it did not provide a feasible solution consistent with the mandate for faculty to maintain sustainable physiology research programs. The costs associated with one-on-one mentoring, and the lack of a sufficient number of faculty members to give intensive attention to undergraduate researchers, make one-on-one mentoring impractical. We therefore developed and implemented the "research-intensive community" model with the aim of aligning diverse goals of participants while simultaneously optimizing research productivity. The fundamental organizational unit is a team consisting of one graduate student and three undergraduates from different majors, supervised by a faculty member. Undergraduate workshops, Graduate Leadership Forums, and computer-mediated communication provide an infrastructure to optimize programmatic efficiency and sustain a multilevel, interdisciplinary community of scholars dedicated to research. While the model radically increases the number of undergraduates that can be supported by a single faculty member, the inherent resilience and scalability of the resulting complex adaptive system enables a research-intensive community program to evolve and grow.