We discuss some of the established and newer views on the role of thrombus in the onset of different coronary syndromes, and in the pathology of both de-novo and restenotic atheromatous plaques, the latter resulting from percutaneous coronary revascularization.
1 Our understanding of asthma and its therapy has changed markedly over the last few years, particularly with the application of molecular and cell biology and the discovery of new and more specific pharmacological tools. 2 Many inflammatory cells participate in the inflammatory process in asthma and mediate a complex mixture of mediators. Cytokines are of particular importance as mediators of chronic inflammation and the means by which cytokines amplify and perpetuate the inflammatory process is now emerging. Airway epithelial cells may be a particularly important source of cytokines and other mediators, such as nitric oxide and endothelin, and may be a major target cell for inhaled steroids, which are the most effective therapy for asthma currently available. 3 The inflammatory process in asthma results not only in bronchoconstriction, but also plasma exudation, the activation of neural mechanisms, mucus secretion. The chronic inflammation may lead to structural changes, including an increase in airway smooth muscle and fibrosis, that are essentially irreversible. There is increasing evidence that transcription factors, such as NF‐κB, play a pivotal role in the expression of inflammatory genes in asthma and may be the major molecular target for glucocorticoids.
Twelve patients with proximal stenosis of the left anterior descending artery, normal myocardial wall motion but without angiographically demonstrable collateral circulation, were studied during transluminal occlusion. Prior to the first transluminal occlusion before crossing the lesion with the balloon, patients were randomly given 0.2 mg nifedipine or its solvent in the left mainstem. The same dose was repeated via the balloon catheter, positioned across the lesion, immediately prior to the second transluminal occlusion. In all patients great cardiac venous flow and ST-elevation were monitored during and after each transluminal occlusion. The lactate extraction ratio A-GCV A (A = arterial, GCV = great cardiac vein) was determined prior to the angioplasty procedure, 10–15 seconds after each transluminal occlusion and 10 minutes after the third transluminal occlusion. Great cardiac venous flow rose significantly to an average of 160% of basal flow when nifedipine was administered into the mainstem before the angioplasty procedure while its solvent had no effect. During each transluminal occlusion, great cardiac venous flow diminished on average by 30% in those who received nifedipine and by 28% in those who received only its solvent. This difference was statistically not significant. After angioplasty great cardiac venous flow was slightly, but not significantly, increased in both groups with respect to basal flow (104% resp. 120% of control). Patients who received nifedipine in the post-stenotic area just before the second transluminal occlusion, had significantly lower lactate production, measured immediately after the transluminal occlusion compared with the patients who received only its solvent (P<0.01). The ST-elevation during the second transluminal occlusion was significantly lower in the nifedipine group (0.1 mm in nifedipine group versus 1.4 mm in solvent group; P<0.05, unpaired t-test). Nifedipine given intracoronary in the post-stenotic area just before coronary angioplasty reduces lactate release and electrocardiographic signs of myocardial ischemic injury. This regional cardioprotective effect seems not due to an enhanced collateral flow, but to a regional cardioplegic effect, which precedes the ischemic event.
<i>Background:</i> Eosinophils play a central role in the induction and perpetuation of allergic inflammatory responses. The present study was performed to investigate the effects of reactive oxygen intermediates on constitutive apoptosis as well as on interleukin (IL)-5 afforded human eosinophil survival. <i>Methods:</i> Peripheral blood eosinophils were isolated by CD16-negative selection to >99% purity and were cultured for 48 h. The number of apoptotic eosinophils in the culture was assessed by flow cytometric analysis of relative DNA content in propidium-iodide-stained cells, annexin-V binding or by morphological analysis. Apoptosis was confirmed by the appearance of a typical ladder pattern in the DNA fragmentation assay by agarose gel electrophoresis. <i>Results:</i> Exogenous H<sub>2</sub>O<sub>2</sub> reversed IL-5-afforded eosinophil survival by inducing apoptosis. Constitutive eosinophil apoptosis was inhibited by a reduction of intracellular levels of H<sub>2</sub>O<sub>2</sub> by catalase. Exogenous H<sub>2</sub>O<sub>2</sub> increased the rate of constitutive apoptosis. <i>Conclusions:</i> Our results suggest that H<sub>2</sub>O<sub>2</sub> may play a role in the downregulation of eosinophilic inflammation by inducing eosinophil apoptosis.
Coronary stents have revolutionised the management of patients with obstructive coronary artery disease. This chapter will review the problems associated with percutaneous coronary intervention when performed using balloon angioplasty and bare-metal stents, before discussing the first and second generation DES. Finally the new generation of drug-eluting stents, which are currently undergoing evaluation in clinical trials, will be reviewed.