Biopsy coupled to quantitative immunofluorescence: a new method to study the human vascular endothelium. J Appl Physiol 92: 1331-1338, 2002; 10.1152/japplphysiol.00680. 2001.-Limited availability of endothelial tissue is a major constraint when investigating the cellular mechanisms of endothelial dysfunction in patients with metabolic and cardiovascular diseases. We propose a novel approach that combines collection of 200-1,000 endothelial cells from a superficial forearm vein or the radial artery, with reliable measurements of protein expression by quantitative immunofluorescence analysis. This method was validated against immunoblot analysis in cultured endothelial cells. Levels of vascular endothelial cell activation, oxidative stress, and nitric oxide synthase expression were measured and compared in five patients with severe chronic heart failure and in four healthy age-matched subjects. In summary, vascular endothelial biopsy coupled with measurement of protein expression by quantitative immunofluorescence analysis provides a novel approach to the study of the vascular endothelium in humans. vascular biology VASCULAR ENDOTHELIAL DYSFUNCTION plays a major role in the pathogenesis of metabolic and cardiovascular diseases. Indirect measurement of reduced nitric oxide (NO) availability in the coronary or in the peripheral circulation is the most frequently assessed parameter of vascular endothelial dysfunction in patients with hypercholesterolemia, diabetes mellitus, hypertension, coronary artery disease, and chronic heart failure (CHF) (1,16,21,22,24,29). However, the vascular endothelium mediates several other physiological and pathological processes besides NO-mediated control of the vasomotor tone. Inflammation, hemostasis, and angiogenesis are all modulated by the vascular endothelium through transitions between quiescent and activated states (30). These nonvasomotor functions of the vascular endothelium are not routinely characterized in patients, primarily because of limited access to the vascular endothelium.Thus the aim of the present investigation was to develop a novel approach to further characterize the vascular endothelial abnormalities that accompany metabolic and cardiovascular diseases. A new minimally invasive technique was designed to safely collect 200-1,000 endothelial cells from either a superficial forearm vein or from the radial artery in human subjects. Measurements of protein expression were performed using quantitative immunofluorescence analysis, an innovative technique that requires only a small number of endothelial cells to accurately quantify intracellular protein levels. Because of our interest in the cellular mechanisms of endothelial dysfunction in patients with CHF, we initially applied this novel approach to quantify oxidative stress by nitrotyrosine formation, endothelial cell activation by nuclear factor-B (NF-B) nuclear translocation and cyclooxygenase-2 (COX-2) expression, and NO synthesis by endothelial NO synthase (eNOS) expression in the vascular endothelium of pati...

Clinical decompensation in CHF is associated with activation of the venous endothelium. Return to a compensated state after short-term inotropic therapy results in a significant reduction in endothelial nitrotyrosine formation, COX-2, and iNOS expression.

Temporary cardiac pacing is commonly used in patients with life-threatening bradycardia and serves as a bridge to implantation of a permanent pacemaker (PPM). For years, passive fixation leads have been used for this purpose, offering the advantage of that they can be placed at bedside. The downside, however, is that patients must remain on telemetry and bed rest until lead removal due to the risk of displacement and failure to capture. Even then, the latter cannot always be prevented. Temporary cardiac pacing with passive fixation leads has also been related to a higher incidence of infection and venous thrombosis, delayed recovery, and increased length of stay. Thus, over the last couple of decades, pacemaker leads with an active fixation mechanism have become increasingly used. This is known as a temporary PPM (TPPM) approach, which carries a very low risk of lead dislodgement and allows patients to ambulate, among other advantages. Here, we performed a review of the literature on the use of TPPMs and their advantages over temporary pacemakers with passive fixation leads and in order to evaluate the advantages and disadvantages of active and passive fixation leads in temporary cardiac pacing. Most articles found were case reports and case series, with few prospective studies. We excluded documents such as editorials and image case reports that provided little to no useful information for the final analysis. The literature search was performed in PubMed, Google Scholar, and other databases and articles written in English and Spanish were considered. Articles were screened up to January 2017. The search keywords used were "temporary permanent pacemaker," "external permanent pacemaker," "active fixation lead," "explantable pacemaker," "hybrid pacing," "temporary permanent generator," "prolonged temporary transvenous pacing," and "semipermanent pacemaker." A total of 24 studies with 770 patients were ultimately included in our review. The age group was primarily above the sixth decade of life, with the exception of one that included pediatric patients. Indications for pacing included device infection, sick sinus syndrome, atrioventricular block, ventricular tachycardia, and bradyarrhythmias associated with systemic illness. The duration of TPPM usage varied from a few days up to 336 days. A total of 18 (2.3%) TPPM-related infections were reported, in which the duration of TPPM use was less than 30 days in at least 15 patients. Loss of capture was documented in only eight patients (1.0%). Complication rates varied from 0% to 30%, with the highest event rates being present in studies that used femoral venous access. In conclusion, although no high-quality studies were identified in our literature search, we found the data retrieved suggest the association of overall favorable outcomes with the use of TPPMs. Device placement and removal typically involve a simple procedure, although fluoroscopy, usually applied in the cardiac catheterization laboratory, is necessary for implantation, which could represent an addition...