Comparison of enterococcal populations related to urban and hospital wastewater in various climatic and geographic European regions.

AIMS: Scarce knowledge about the distribution of enterococci species in wastewaters limits any statement on their reliability as faecal indicators or the implications of antibiotic resistance transmission by these organisms through the water cycle. Enterococci have been involved in nosocomial infections and the spreading of antibiotic resistance through the food chain. The species distribution of enterococci and the presence of resistant strains to vancomycin and erythromycin were analysed in more than 400 raw and treated urban wastewaters, surface waters receiving these treated wastewaters and hospital wastewaters from three European countries. METHODS AND RESULTS: A total of 9296 strains were isolated and biochemically phenotyped. The species identification was based on the comparison of biochemical profiles with those of more than 20000 enterococci isolates from an international study. The prevalence of enterococcal isolates resistant to erythromycin (ERE) and vancomycin (VRE) was also analysed. ERE strains were present in a high proportion in all the studied samples. VRE strains were also isolated in all studied countries despite the time elapsed since the use of antimicrobial glycopeptides in animal production was banned in the European Union. CONCLUSIONS: Enterococcus faecalis and Ent. faecium were the most abundant species in all the studied wastewaters. All the studied wastewaters demonstrated high diversity and similar population structure and composition. ERE and VRE isolates were detected in most of the wastewaters. SIGNIFICANCE AND IMPACT OF THE STUDY: Urban and hospital wastewaters are useful targets for the evaluation of the prevalence of ERE and VRE isolates in the environment. It appears that these bacteria could pass through wastewater treatment plants and be transferred to surface waters.

Femoral complications and bed rest duration after coronary arteriography.

This randomized study using a pneumatic compression device found no significant difference in the femoral complication rate between 4 and 6 hours of bed rest after Judkin's coronary arteriography. The positive implications for the organization of an efficient service in busy tertiary centers include reduced patient discomfort, earlier ambulation and discharge, efficient staff deployment, and enhanced throughput.

Myocardial hibernation.

Myocardial hibernation is a potentially reversible cause of resting left ventricular dysfunction in some patients with coronary artery disease. Successful revascularisation in these patients can lead to improved ventricular function and hence improved prognosis. This review discusses the pathophysiology of myocardial hibernation and the methods that are currently available to detect it.

Clinical evaluation of a dual sensor, rate responsive pacemaker.

UNLABELLED: Dual sensor pacemakers should respond more appropriately during differing exercise modes than a single sensor device. The Topaz model 515 (QT and activity count [ACT] sensing) pacemaker shows appropriate rate response during treadmill exercise testing. We postulated that adjustments to relative sensor contribution should allow fine tuning of the onset of rate response. Eleven patients with this pacemaker were studied. Three standard exercise tests were performed with adjustment of sensor blending and activity threshold between each one. We also assessed the response to isometric exercise and a false positive activity signal. RESULTS: Times to 100 ppm (3.7 +/- 1.3, 4.4 +/- 2.0, 5.3 +/- 1.5 mins), times to peak rate (6.1 +/- 1.6, 5.6 +/- 1.4, 6.5 +/- 1.3 mins) and accelerations to peak (9.0 +/- 2.4, 9.2 +/- 5.3, 7.7 +/- 2.8 ppm/min) were measured in all three different sensor settings (QT = ACT, QT < ACT, and QT = ACT with decreased activity threshold). No significant difference in onset of rate response was seen between the three settings. Tapping (false-positive activity) provided a rapid rise in paced rate to 79 ppm from a resting value of 65 ppm. This came down to 71 ppm demonstrating satisfactory sensor cross-checking. Isometric exercise induced a moderate response from 65 ppm at rest to 74 ppm after 3 minutes. CONCLUSIONS: Satisfactory rate response was demonstrated in most patients to treadmill testing and to isometric exercise. However, small adjustments to relative sensor contributions do not predictably alter the onset of rate response.

Dipyridamole is superior to dobutamine for thallium stress imaging: a randomised crossover study.

OBJECTIVE: To assess the value of dobutamine over dipyridamole as a pharmacological stressing agent in myocardial perfusion imaging with thallium-201. DESIGN: Stress and redistribution tomographic images were taken in a group of patients in a randomised crossover study of both agents. The scans were scored to give a value for the stress and redistribution images and a reversibility score (redistribution--stress). All patients had coronary angiography that was also scored. Differences between the two agents were compared by a paired t test. PATIENTS: 30 patients aged 51-70 years with chest pain thought to be caused by myocardial ischaemia. 11 had had previously myocardial infarction. RESULTS: Dipyridamole caused adverse symptoms in six patients whereas dobutamine caused symptoms in 21 patients (chi 2 = 15.15, p < 0.0001). Dobutamine stress took considerably longer than dipyridamole (31 v 6 minutes) and cost more (17 pounds v 1.50 pounds). There were no significant differences between the agents in terms of total stress or redistribution scores, but regional analysis showed that dipyridamole showed significantly more defects during stress at the apex and lateral wall (p < 0.05), with no significant difference at redistribution. Dipyridamole stress also caused significantly more reversible defects at the apex (p < 0.05) and gave a better correlation than dobutamine with coronary score (dipyridamole r = 0.80, p < 0.001 v dobutamine r = 0.64, p < 0.001). In six patients who had continued to take beta blockers the results of dobutamine stress did not correlate with coronary score, r = 0.34 (NS), whereas dipyridamole studies were not affected. CONCLUSION: Compared with dobutamine, dipyridamole was as effective in producing overall perfusion defects and more effective in provoking defects at the apex and lateral segment. The dipyridamole study correlated better with coronary score and was not affected by concurrent beta blocker treatment. It was also better tolerated by the patients, was less time consuming, and was much cheaper.

Measurement of tissue-bound amiodarone and its metabolites by computed tomography.

Amiodarone is strongly tissue-bound and serum levels are a poor guide to therapeutic efficacy. The electrocardiographic measure of the QT interval corrected for heart rate (QTc) is a better guide but is unhelpful in patients with bundle branch block or U-waves on the electrocardiogram. Myocardial amiodarone levels are the most accurate guide but are not easy to obtain. There is, however, a relationship between myocardial concentration and hepatic concentration of amiodarone and its metabolites. Since amiodarone contains iodine, and there is hepatic uptake, the increased hepatic attenuation from single slice computed tomography was compared with serum levels and the electrocardiographic QTc in 12 patients before and during amiodarone therapy. Hepatic attenuation increased by a mean value of 18.25 HU over a 12 month study period. This increase correlated well with increased QTc (r = 0.83) and with serum amiodarone levels (r = 0.89), but less well with serum desethyl amiodarone levels (r = 0.43). An iodine-containing phantom was used to construct a curve of attenuation against iodine concentration in mol/l. Thus an indirect measurement of amiodarone concentration in g/l wet weight of liver could be determined.

Characterization of pulsed-dye laser-mediated vasodilatation in a rabbit femoral artery model of vasoconstriction.

Vasoconstriction is a clinical problem associated with invasive vascular procedures, microvascular reconstruction and subarachnoid hemorrhage. We sought to characterize the ability of pulsed-dye laser irradiation to reverse and prevent vasoconstriction in an anesthetized rabbit model of surgically and pharmacologically induced vasoconstriction. Five groups of experiments were performed to study the effect of pulsed-dye laser irradiation delivered through a 320 microns core ball-tip fiber into the femoral artery. The studies demonstrated that pulsed-dye irradiation can reproducibly cause vascular dilatation. The zone of vasodilatation propagated equally proximal and distal to the site of irradiation within the vessel. When saline was infused into the vessel to replace flowing blood during delivery of laser irradiation, no significant vasodilatation occurred. After laser irradiation reversed surgical and pharmacologic vasoconstriction, the vessel was resistant to further pharmacologic vasoconstriction. This resistance to pharmacologic vasoconstriction did not occur if the vessel was pharmacologically predilated before delivery of laser irradiation. Pathologic analysis of the vessels revealed endothelial damage and mild to moderate medial necrosis, most significant at the site of energy delivery. These studies provide characterization of pulsed-dye laser-mediated vasodilatation in an in vivo model. Delivery of pulsed-dye laser energy has potential clinical application and warrants further investigation.

Influence of respiratory variations on right ventricular function.

Respiratory effort during inspiration, expiration, and the Valsalva manoeuvre changes right ventricular preload and afterload. On inspiration these changes should improve systolic emptying of a larger end diastolic volume and so increase the ejection fraction, whereas on expiration the reverse should be true. The resting right ventricular ejection fraction was measured by first pass radionuclide angiography with gold-195m (half life 30.5 s) in 17 individuals at maximal inspiration and expiration and in eight at rest and during the strain phase (phase 2) of the Valsalva manoeuvre. The right ventricular ejection fraction was significantly lower during expiration than during inspiration. There were, however, no significant differences in bolus duration or right ventricular transit time. The Valsalva manoeuvre, in contrast, significantly increased the ejection fraction and also significantly prolonged both the bolus duration and right ventricular transit time. The conformation of the bolus curves during the Valsalva manoeuvre suggested the development of tricuspid regurgitation. These data suggest that relative influences of venous return, pulmonary arterial pressure, pulmonary vascular resistance, and possible functional tricuspid regurgitation vary during inspiration, expiration, and the Valsalva manoeuvre and can affect the right ventricular ejection fraction. Changes in right ventricular function on exercise assessed by first pass radionuclide angiography must be interpreted with caution because maximal respiratory effort may alter the right ventricular ejection fraction independently of ischaemia or other non-ischaemic factors.

Nonischemic changes in right ventricular function on exercise. Do normal volunteers differ from patients with normal coronary arteries?

Factors other than ischemia may alter right ventricular function both at rest and on exercise. Normal volunteers differ from cardiac patients with normal coronary arteries with regard to their left ventricular response to exercise. This study examined changes in right ventricular function on exercise in 21 normal volunteers and 13 patients with normal coronary arteries, using first-pass radionuclide angiography. There were large ranges of right ventricular ejection fraction in the two groups, both at rest and on exercise. Resting right ventricular ejection fraction was 40.2 +/- 10.6% (mean +/- SD) in the volunteers and 38.6 +/- 9.7% in the patients, p = not significant, and on exercise rose significantly in both groups to 46.1 +/- 9.9% and 45.8 +/- 9.7%, respectively. The difference between the groups was not significant. In both groups some subjects with high resting values showed large decreases in ejection fraction on exercise, and there were significant negative correlations between resting ejection fraction and the change on exercise, r = -0.59 (p less than 0.01) in volunteers, and r = -0.66 (p less than 0.05) in patients. Older volunteers tended to have lower rest and exercise ejection fractions, but there was no difference between normotensive and hypertensive patients in their rest or exercise values. In conclusion, changes in right ventricular function on exercise are similar in normal volunteers and in patients with normal coronary arteries. Some subjects show decreases in right ventricular ejection fraction on exercise which do not appear to be related to ischemia.

Effects of nisoldipine on left ventricular function during exercise or cold pressor stress.

The effects of a single oral dose of nisoldipine, 10 mg, were investigated in two groups of patients. Firstly, the effects of nisoldipine on exercise left ventricular function were assessed in 20 patients with chronic stable angina and coronary disease. Secondly, the effects of nisoldipine on the left ventricular response to cold pressor stimulation were examined in 12 patients with normal coronary arteries, who presented with typical ischaemic chest pain and abnormal exercise tests. All studies were performed using first pass radionuclide angiography and the new short half-life radiopharmaceutical, gold-195m. In patients with coronary disease, mean exercise time improved after nisoldipine (P less than 0.01). Both at the identical workload to that before treatment, and at a new peak workload, mean exercise left ventricular ejection fraction (LVEF) improved significantly after nisoldipine (P less than 0.01 and P less than 0.05 vs pretreatment levels, respectively). At the identical workload to that before treatment, 10 of 16 patients, who had initially developed angina, did not develop angina after nisoldipine, and 23 of 46 exercise-induced regional left ventricular abnormalities had normalized. In the patients with normal coronary arteries undergoing cold pressor stimulation, imaging was carried out at rest, and after 1 and 2.5 minutes of cold stimulation, before and one hour after oral nisoldipine. LVEF fell significantly during cold stimulation before nisoldipine administration, with 10 of the 12 patients showing an abnormal response. Nisoldipine did not lead to any attenuation of the heart rate and blood pressure response to cold, but mean LVEF did not fall at any cold pressor stage and only three patients showed an abnormal response.(ABSTRACT TRUNCATED AT 250 WORDS)

Global and regional right ventricular function after acute myocardial infarction: dependence upon site of left ventricular infarction.

The relation of global and regional right and left ventricular function during the acute phase after a first myocardial infarction was assessed by first pass radionuclide angiography in 20 patients (10 after anterior and 10 after inferior myocardial infarction). The right ventricular ejection fraction did not differ significantly between the groups, but left ventricular ejection fraction was significantly depressed after anterior myocardial infarction. There was evidence of right ventricular dilatation and impaired transit in the group with inferior infarction. Five patients with anterior infarction and six with inferior infarction had abnormal right ventricular ejection fractions. Right ventricular wall motion abnormalities affected the septal wall in the group with anterior infarction and the free wall in the group with inferior infarction. The relation between right and left ventricular ejection fractions was markedly different in the two groups. In the group with anterior infarction there was a significant linear relation between right and left ventricular ejection fraction, whereas in the group with inferior infarction there was not. Thus right ventricular dysfunction commonly occurs after both anterior and inferior myocardial infarction. Right and left ventricular impairment are related after anterior myocardial infarction, but are independent after inferior myocardial infarction. Finally, the different effects of anterior and inferior myocardial infarction on right ventricular function may be explained by differences in septal and free wall involvement.

Sex differences in exercise induced left ventricular dysfunction in patients with syndrome X.

Clinical, electrocardiographic, and scintigraphic data were reviewed from 32 patients (18 men and 14 women) who had syndrome X (chest pain, evidence of ischaemia, and normal coronary arteries without coronary vasospasm). The mean (SD) resting left ventricular ejection fraction, determined by first pass radionuclide angiography was 62.6 (9.2)% and was greater than 50% in all subjects. There was no significant difference between men and women. On exercise, left ventricular ejection fraction decreased significantly to 57.4 (13.0)%. In 17 of 32 subjects there was a fall in left ventricular ejection fraction of greater than 5%, and regional wall motion abnormalities developed in 12 subjects. The fall in left ventricular ejection fraction on exercise was significant in women (from 61.9 (8.5)% at rest to 54.0 (9.8)% on exercise) but not in men (from 63.2 (9.8)% at rest to 60.0 (14.8)% on exercise). Exercise left ventricular ejection fraction fell by greater than 5% in 10 (71%) of 14 women and in seven (39%) of 18 men. Dyskinetic segments developed in eight (57%) of 14 women and only four (22%) of men. Exercise duration in women was significantly shorter than in men (4.1 (1.5) vs 6.6 (2.1) minutes) and was the only one of several clinical and scintigraphic variables that correlated with the change in left ventricular ejection fraction on exercise. In this selected group of subjects with chest pain and angiographically normal coronary arteries, exercise induced left ventricular dysfunction, as shown by a fall in ejection fraction or the development of regional abnormalities, is a common finding. These are more likely to occur in women than men and are associated with a lower exercise capacity. The data suggest that the sex of the patient is important in the interpretation of the non-invasive evaluation of subjects suspected of having syndrome X.

Duration of action of tiapamil in stable exercise induced angina.

The duration of action of tiapamil was assessed in ten patients with stable exertional angina. Maximal symptom-limited treadmill exercise electrocardiography was performed before and at 1, 3, 6 and 9 h after therapy. Significant differences were only found at 1 h after tiapamil with increases in mean exercise duration (312 vs 399 s), the time to onset of angina (221 vs 310 s) and exercise work load (5.9 vs 7.3 METS). Tiapamil had no significant effect on the exercise heart rate but increased the resting heart rate by 6 beats/minute. The resting systolic blood pressure fell by 17 mmHg (p less than 0.01), and the diastolic blood pressure by 14 mmHg. Exercise systolic and diastolic blood pressures fell by 19 and 17 mmHg respectively. Side-effects were short-lived and attributable to vasodilatation. Tiapamil is effective for the relief of angina with minimal side-effects, but its duration of action is short. For effective chronic oral use, a sustained release preparation is required.