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Cardiac surface conduction velocities could provide valuable information about the speed and angle of a propagating electrical wave front. It would be advantageous to develop catheter-based velocity mapping devices to improve the visualization of cardiac arrhythmias. However, catheter tip size is limited to < or = 2.5 mm in diameter, restricting the number(More)
Vascular smooth muscle cells exhibit varied responses after vessel injury and surgical interventions, including phenotypic switching, migration, proliferation, protein synthesis, and apoptosis. Although the source of the smooth muscle cells that accumulate in the vascular wall is controversial, possibly reflecting migration from the adventitia, from the(More)
BACKGROUND Pseudomembranous colitis has increased in incidence and severity over the past 10 years. Toxic megacolon is a rare but reported presentation of severe pseudomembranous colitis. This article reviews the reported cases of Clostridium difficile with toxic megacolon in the literature and introduces an additional case that underscores the importance(More)
OBJECTIVES Ephrin ligands and Eph receptors are signaling molecules that are differentially expressed on arteries and veins during development. We examined whether Eph-B4, a venous marker, and Ephrin-B2, an arterial marker, are regulated during vein graft adaptation in humans and aged rats. METHODS AND RESULTS Eph-B4 transcripts and immunodetectable(More)
BACKGROUND/AIMS Age-associated changes in endothelial nitric oxide synthase (eNOS) expression have not been definitively linked to the pathophysiology of aortic aneurysms. We examined the role of eNOS in human patients and an age-appropriate mouse model. METHODS eNOS transcripts and immunodetectable protein were assessed by quantitative PCR and(More)
BACKGROUND The safety and efficacy of carotid endarterectomy (CEA) in stroke prevention has been well documented. But "high-risk" patients have traditionally been excluded from these studies and may be offered alternate therapies. We examined the safety of CEA in veterans, a medically high-risk group with multiple comorbidities. STUDY DESIGN The records(More)
Automated techniques for locating cardiac arrhythmia features are limited, and cardiologists generally rely on isochronal maps to infer patterns in the cardiac activation sequence during an ablation procedure. Velocity vector mapping has been proposed as an alternative method to study cardiac activation in both clinical and research environments. In(More)
Arteries and veins have been historically defined by the direction of blood flow and oxygen tension within the vessel, in addition to their functional, hemodynamic, and anatomical differences. It is now known that the molecular identity of these vessels is genetically predetermined, with specific molecular pathways activated during the development of(More)
Vascular smooth muscle cells (SMC) may be directly exposed to blood flow after an endothelial-denuding injury. It is not known whether direct exposure of SMC to shear stress reduces SMC turnover and contributes to the low rate of restenosis after most vascular interventions. This study examines if laminar shear stress inhibits SMC proliferation or(More)
OBJECTIVE Older patients are thought to tolerate acute ischemia more poorly than younger patients. Since aging may depress both angiogenesis and arteriogenesis, we determined the effects of age on both angiogenesis and arteriogenesis in a model of severe acute limb ischemia. METHODS Young adult (3-months-old) and aged (18-months-old) C57BL/6 mice(More)