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We report an unusual case of acute myocarditis associated with Campylobacter jejuni enterocolitis leading to severe impairment of left ventricular systolic function. Contrast-enhanced cardiac magnetic resonance imaging was used to confirm the presence of acute myocardial inflammation and its resolution.

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AIM: To compare the immediate and late outcomes of patients treated by a policy of routine stent implantation with routine balloon angioplasty and the use of stents only when an ideal result has not been obtained. METHODS: A nine centre, multinational, randomised study of 300 patients with coronary artery disease thought suitable for treatment of a single lesion by balloon angioplasty or stent implantation. Only new lesions in patients who had not undergone previous bypass surgery were included, and totally occluded vessels were excluded. RESULTS: The initial procedure was considered successful in 96% of patients. There was more complete angiographic restoration of luminal diameter in patients treated by elective stent (minimum lumen diameter (MLD) 2.68 mm for stent v 2.27 mm for balloon; p < 0.007), but analysis of the subgroup of balloon angioplasty patients who crossed over to stenting showed that they achieved similar results to the elective stent group. Late luminal loss was greater in stented patients than in those undergoing balloon angioplasty only, and by six months the angiographic benefit of stenting had disappeared (MLD 1.90 mm for stent group v 2.00 mm for balloon angioplasty). Angiographic and clinical results in the balloon angioplasty group were assisted by the high crossover rate (30.1%). Both groups had similar symptom relief, with 58.9% of patients improving by two or more angina grades. The need for further revascularisation was also similar in the two groups at one year (18.2% in the stented group v 17.1% in the balloon angioplasty group). Haemorrhagic complications at the local arterial entry site were more common than expected and were distributed equally between the patients receiving full anticoagulation and those receiving antiplatelet treatment only. The results of both Wiktor stent placement and balloon angioplasty were similar to the findings in the stent group in previous randomised studies (Benestent II, STRESS). CONCLUSIONS: Provisional stenting appears to offer the same longer term outcome as elective stenting in this selected group of patients. Improvement in the results of conventional balloon angioplasty in the past 10 years means that a policy of obtaining an ideal result without the use of stents appears to be practicable in many of these patients, with consequent cost savings.

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OBJECTIVE: Coronary occlusion in the rabbit reduces the delivery of particulate tracers to close to zero, but exchange of diffusible solutes, derived from non-arterial sources, continues at a significant level. We investigated the relationships between the exchange of diffusible solutes during coronary occlusion and the extent of myocardial necrosis and between duration of ischaemia and the extent of recovery of solute exchange during reflow. METHODS: In an anaesthetised rabbit model of regional ischaemia and reflow, solute exchange is measured using the voltammetric hydrogen clearance technique. The area at risk and infarct size are determined ex vivo with monastral blue and nitroblue tetrazolium staining, respectively. Three groups are studied: control perfusion for 130 minutes (group A); 30 minutes coronary ligation followed by 90 minutes reflow (group B) and 40 minutes coronary ligation followed by 90 minutes reflow (group C). RESULTS: There was no significant difference in area at risk between the groups B and C (50 +/- 2% and 45 +/- 5%; p = ns) or in infarct size when expressed relative to the area at risk (42 +/- 7% and 55 +/- 5%; p = ns). During coronary ligation hydrogen clearance remained constant at 22 +/- 4% of the control region in group B and 32 +/- 4% in group C, at the same time period in group A it was 87 +/- 2% (ANOVA = p < 0.05, with a significant non-linear trend). Although the duration of ischaemia and the level of solute exchange during ischaemia did not correlate individually with the extent of myocardial necrosis, together they showed a significant correlation (ANOVA; p < 0.05). Following coronary occlusion, hydrogen clearance recovered to 72 +/- 9% after 30 minutes ischaemia but only to 57 +/- 5% following 40 minutes ischaemia and was 95 +/- 2% in the control group (ANOVA between the three groups p < 0.05 with a significant linear trend). Myocardial hydration fell in the apical region following coronary ligation by 27 +/- 5% in group B and by 25 +/- 5% in group C, and rose on reperfusion but only to 80 +/- 3% in group B and 83 +/- 3% in group C of their preligation values. CONCLUSION: In collateral deficient myocardium, the extent of myocardial necrosis is dependent on the level of solute exchange occurring during ischaemia. The level of solute exchange during reflow is dependent on the duration of ischaemia.

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OBJECTIVE: Myocardial perfusion can be determined by many techniques which can be broadly divided into those employing particulate tracers and those employing diffusible tracers. The most commonly used particulate tracer is radioactive microspheres. However, as with other particulate tracers, they only determine convective transport from pre-capillary arterioles. If convective transport is the limiting factor in solute exchange, then particulate tracers will give comparable measurements to diffusible tracer techniques. However, if solute transport becomes diffusion-limited or alternative pathways of convective transport become more important, which may occur during regional ischaemia, perfusion visualised with clearance techniques using diffusible tracers may be greater than that determined with particulate tracers. This study set out to investigate this possibility in the rabbit myocardium under normal and ischaemic conditions. METHODS: A pentobarbitone-anaesthetised rabbit model of regional ischaemia was used. Ischaemia of the apical region was induced by ligation of the large left ventricular branch of the circumflex artery. Tissue perfusion was determined by radioactive microspheres (n = 5) and the clearance of hydrogen, which was detected voltammetrically by platinum microelectrodes (n = 5). Measurements were made prior to and following coronary ligation and the ischaemic region was demarcated using the particulate tracer monastral blue. The exchange of diffusible solutes was visualised using digital fluorescence microscopy on histological sections of tissue following systemic administration of the fluorophore Evans blue labelled albumin (n = 4). RESULTS: Coronary ligation produced an ischaemic zone occupying 50 +/- 13% of the left ventricle. In ischaemic tissue, flow determined by microspheres fell to 3.9 +/- 4.1% of its pre-ligation value, but solute exchange fell only to 22 +/- 10% (adjusted for changes in the partition coefficient of H2 during ischaemia, P < 0.05). Perfusion measured by microspheres and hydrogen clearance was unchanged in the non-ischaemic area during coronary ligation. There was preferential uptake of Evans blue albumin towards the endocardial surface in the ischaemic region and areas of local uptake through the ventricular wall, which were possibly associated with vessels. CONCLUSION: This work demonstrates that under normal physiological conditions nutrient supply is determined by pre-capillary delivery. However, during ischaemia diffusive transport plays an increasingly important role. The alternative pathways for solute exchange are likely to have an important influence on the rate and extent of myocardial necrosis during coronary occlusion.

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Despite variable efficacy in achieving recanalization, different thrombolytic agents demonstrate similar abilities to reduce mortality following myocardial infarction. We investigated whether factors other than the ability to achieve coronary artery recanalization are important in mediating the beneficial effects associated with thrombolytic therapy during acute myocardial infarction using anaesthetized rabbits. Coronary artery occlusion was produced using either a single ligature (which was released to initiate reperfusion) or by placing two ligatures 5 mm apart to allow the formation of an intraluminal thrombus. In this case, ligature removal followed by thrombolysis was required for recanalization to occur. Experiments were performed in the presence and absence of streptokinase. Streptokinase was most effective in reducing myocardial necrosis when associated with thrombolytic recanalization (total left ventricular infarct size was reduced from 37 +/- 7% to 13 +/- 1%, P < 0.01). However, streptokinase also reduced infarct size in the absence of reperfusion (45 +/- 4% vs 35 +/- 2%, P < 0.05), although further work is needed to clarify the mechanisms.

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1. The effects of cicletanine on arrhythmias, haemodynamics and extent of necrosis during myocardial ischaemia were investigated in rabbits subjected to coronary ligation. 2. Cicletanine increased cardiac output prior to coronary occlusion (P < 0.01) but had no other significant haemodynamic effects at this time and did not significantly alter heart rate, blood pressure or cardiac output during 30 min of ischaemia or 30 min of reperfusion. 3. Ventricular fibrillation and mortality were greater in control (65% and 60% respectively) than treated animals (15.4% and 15.4%, P < 0.01). 4. The extent of myocardial necrosis expressed as a percentage of the area at risk was also reduced by cicletanine from 61 +/- 8% in controls to 37 +/- 6% (P < 0.05). 5. These findings indicate that cicletanine attenuates arrhythmias and preserves myocardium in the early phase of ischaemia and this effect appears to be independent of an established antihypertensive action.

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1. The effects of two novel platelet activating factor (PAF) antagonists BN50726 and BN50739 on arrhythmias, haemodynamics and extent of necrosis during myocardial ischaemia and reperfusion were investigated in anaesthetized rabbits subjected to coronary artery ligation. 2. BN50739 reduced heart rate prior to coronary artery occlusion (P < 0.005) but had no other significant haemodynamic effects at this time. BN50739 and BN50726 did not significantly alter heart rate or blood pressure during 30 min of ischaemia or 30 min of reperfusion, compared to control hearts. 3. BN50739 and BN50726 had no effect on the incidence of arrhythmias during ischaemia. BN50726 significantly reduced the incidence of reperfusion ventricular fibrillation compared to controls (0% v 40%, P < 0.05), and improved survival (80% v 39%, P < 0.05). Similar trends were observed with BN50739. 4. BN50726 reduced the extent of necrosis compared to control hearts (18 +/- 2% v 30 +/- 3%, P < 0.01). A similar trend was observed with BN50739. 5. These results demonstrate that PAF antagonism with BN50726 attenuates reperfusion-induced arrhythmias and preserves myocardium in the early phase of ischaemia, independently of haemodynamic effects.

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1-Naphthol has recently been shown to be selectively toxic to short-term organ cultures of human colorectal tumor tissue. The mechanism underlying 1-naphthol's selective toxicity is as yet unknown, but may be due to the formation of naphthoquinone metabolites, which are known to be highly toxic to tumor cells. By using high-performance liquid chromatography with reductive electrochemical detection, it has been possible to show that 1-naphthol is converted to naphthoquinone metabolites by rat liver microsomes. At least two metabolic pathways, independent of cytochrome P-450, appear to be involved. Iron-dependent lipid peroxidation appears to be responsible for at least part of the conversion of 1-naphthol to predominantly 1,4-naphthoquinone, and it seems likely that superoxide anion radical generation by NADPH-cytochrome P-450 reductase could also catalyze this conversion. 1-Naphthol therefore seems to be converted to cytotoxic naphthoquinone metabolites by mechanism(s) dependent upon the generation of free radicals in rat liver microsomes. The results also demonstrate the utility of HPLC with reductive electrochemical detection for investigations of quinone metabolite formation and the measurement of quinones of both physiological and environmental interest.

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