No abstract

Kaede is a photoconvertible fluorescence protein that changes from green to red upon exposure to violet light. The photoconversion of intracellular Kaede has no effect on cellular function. Using transgenic mice expressing the Kaede protein, we demonstrated that movement of cells with the photoconverted Kaede protein could be monitored from lymphoid organs to other tissues as well as from skin to the draining lymph node. Analysis of the kinetics of cellular movement revealed that each subset of cells in the lymph node, such as CD4 ؉ T, CD8 ؉ T, B, and dendritic cells, has a distinct migration pattern in vivo. Thus, the Kaede transgenic mouse system would be an ideal tool to monitor precise cellular movement in vivo at different stages of immune response to pathogens as well as in autoimmune diseases.cell migration ͉ dendritic cells ͉ lymphocyte ͉ photoconvertible protein

Background-The summit of the left ventricle (LV) is the most superior portion of the epicardial LV bounded by an arc from the left anterior descending coronary artery, superior to the first septal perforating branch to the left circumflex coronary artery. Ventricular arrhythmias (VAs) originating from this region may present challenges for catheter ablation. Methods and Results-We studied 27 consecutive patients with VAs originating from the LV summit. The great cardiac vein (GCV) divides this region between an inferior area accessible to ablation and a superior, inaccessible area. Successful ablation was achieved within the GCV in 14 patients and on the epicardial surface in 4. Ventricular prepotentials were recorded at the successful ablation site in 80% of these patients. In 5 patients, ablation was abandoned because of inaccessibility of the catheter to the myocardium or high impedance with radiofrequency application within the GCV. In the remaining 4 patients, epicardial mapping suggested VA origins in a region of low voltage that was located superior to the GCV (inaccessible area), and ablation was abandoned because of close proximity to the coronary arteries or high impedance. A right bundle-branch block, transition zone, R-wave amplitude ratio in leads III to II, Q-wave amplitude ratio in leads aVL to aVR, and S waves in lead V 6 accurately predicted the site of origin. Conclusions-LV summit VAs may be ablated within the GCV or inferior to the GCV on the epicardial surface, though sites superior to the GCV are usually inaccessible to ablation. (Circ Arrhythm Electrophysiol. 2010;3:616-623.)

There are differences in the electrocardiographic and electrophysiological features among VAs originating from these regions that are helpful for their diagnosis and effective catheter ablation.