Active thermoregulation improves outcome of off-pump coronary artery bypass

During off-pump coronary artery bypass grafting, hypothermia increases vasoconstriction, myocardial afterload, coagulopathy and postoperative bleeding. Traditional thermoregulatory techniques do not maintain core body temperature intraoperatively. The efficacy of a commercially available, computer-controlled, water-circulating, dorsal surface, active warming system for thermoregulatory control was evaluated. All patients who underwent non-emergency off-pump coronary bypass grafting by a single surgeon in a 1-year period were studied: the thermoregulation device was used in 50 cases and unavailable for use in 19. The patients who underwent active thermoregulation demonstrated significantly improved core body temperatures compared to the controls: lowest intraoperative, 35.8 degrees C +/- 0.1 degrees C vs. 35.0 degrees C +/- 0.2 degrees C; immediately postoperative, 36.5 degrees C +/- 0.1 degrees C vs. 35.6 degrees C +/- 0.2 degrees C; and 1-hour postoperative, 36.6 degrees C +/- 0.1 degrees C vs. 35.9 degrees C +/- 0.2 degrees C. Thermoregulated patients had significantly reduced 24-hour chest tube drainage (764 +/- 38 vs. 1227 +/- 183 mL), packed red blood cell transfusions (1.4 +/- 0.2 vs. 3.3 +/- 0.7 units), time to extubation (6.8 +/- 0.5 vs. 11.4 +/- 2.3 hours), intensive care unit stay (1.3 +/- 0.1 vs. 2.0 +/- 0.3 days), and hospital stay (4.3 +/- 0.1 vs. 5.1 +/- 0.3 days).     

Actin has a molecular scaffolding,not propulsive,role in presynaptic function

We used actin tagged with enhanced green fluorescent protein (EGFP-actin) to characterize the distribution and dynamics of actin in living presynaptic terminals in rat CNS neurons. Actin was preferentially concentrated around--and appeared to surround--the presynaptic vesicle cluster. In resting terminals, approximately 30% of actin was found to be in a polymerized but dynamic state, with a remodeling time scale of approximately 20 s. During electrical activity, actin was further polymerized and recruited from nearby axonal regions to the regions surrounding vesicles. Treatment of terminals with the actin monomer-sequestering agent latrunculin-A completely dispersed the actin network and abolished activity-dependent actin dynamics. We used a variety of methods to examine the role of actin in the presynaptic vesicle cycle. These data rule out a propulsive role for actin, either in maintaining the vesicle cluster or in guiding vesicle recycling. Instead, we propose that actin acts as a scaffolding system for regulatory molecules in the nerve terminal.     

Mitral valve surgery for dilated cardiomyopathy: current status and future roles

There are a large number of patients with functional mitral regurgitation resulting from dilated cardiomyopathy. The decision between surgical correction and medical management of severe mitral regurgitation in heart failure can be difficult. The data regarding long-term benefits and mortality after surgical intervention are contradictory. Recent data suggest that mitral regurgitation can be surgically corrected in heart failure with symptomatic improvements and beneficial reverse remodeling. Contrary to prior beliefs, mitral valve repair can be performed safely with minimal postoperative mortality. Data from multi-institutional, randomized prospective trials will help to elucidate many of the questions and concerns regarding repair of severe functional mitral regurgitation.