These results demonstrate that cigarette smoking and hypercholesterolemia synergistically impair endothelial function and that their combined presence is associated with increased plasma levels of autoantibodies against oxidized LDL. These observations raise the possibility that long-term smoking potentiates endothelial dysfunction in hypercholesterolemic patients by enhancing the oxidation of LDL.
Abstract-Oxidative processes play an important role in atherogenesis. Because superoxide anion and nitric oxide (NO) are important mediators in vascular pathology, we studied the expression of extracellular superoxide dismutase (EC-SOD) and inducible nitric oxide synthase (iNOS) in human and rabbit atherosclerotic lesions by using simultaneous in situ hybridization and immunocytochemistry and EC-SOD enzyme activity measurements. We also analyzed the presence in the arterial wall of oxidized lipoproteins and peroxynitrite-modified proteins as indicators of oxidative damage and possible mediators in vascular pathology. EC-SOD and iNOS mRNA and protein were expressed in smooth muscle cells and macrophages in early and advanced lesions. The expression of both enzymes was especially prominent in macrophages. As measured by enzyme activity, EC-SOD was the major SOD isoenzyme in the arterial wall. EC-SOD activity was higher in highly cellular rabbit lesions but lower in advanced, connective tissue-rich human lesions. Despite the abundant expression of EC-SOD, malondialdehyde-lysine and hydroxynonenal-lysine epitopes characteristic of oxidized lipoproteins and nitrotyrosine residues characteristic of peroxynitrite-modified proteins were detected in iNOS-positive, macrophage-rich lesions, thus implying that malondialdehyde, hydroxynonenal, and peroxynitrite are important mediators of oxidative damage. We conclude that EC-SOD, iNOS, and the balance between NO and superoxide anion play important roles in atherogenesis. EC-SOD and iNOS are highly expressed in lesion macrophages. High EC-SOD expression in the arterial wall may be required not only to prevent deleterious effects of superoxide anion but also to preserve NO activity and prevent peroxynitrite formation. Modulation of arterial EC-SOD and iNOS activities could provide means to protect arteries against atherosclerotic vascular disease. (Arterioscler Thromb Vasc Biol. 1998;18:157-167.)
Market orientation (MO) and marketing performance measurement (MPM) are two of the most widespread strategic marketing concepts among practitioners. However, some have questioned the benefits of extensive investments in MO and MPM. More importantly, little is known about which combinations of MO and MPM are optimal in ensuring high business performance. To address this research gap, the authors analyze a unique data set of 628 firms with a novel method of configurational analysis: fuzzy-set qualitative comparative analysis. In line with prior research, the authors find that MO is an important determinant of business performance. However, to reap its benefits, managers need to complement it with appropriate MPM, the level and focus of which vary across firms. For example, whereas large firms and market leaders generally benefit from comprehensive MPM, small firms may benefit from measuring marketing performance only selectively or by focusing on particular dimensions of marketing performance. The study also finds that many of the highest-performing firms do not follow any of the particular best practices identified.
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