Laboratory strains of Bacillus anthracis lose their ability to rapidly grow and sporulate compared to wildlife outbreak strains

Bacillus anthracis is the causative agent of anthrax in animals and humans. The organism lies in a dormant state in the soil until introduced into an animal via, ingestion, cutaneous inoculation or inhalation. Once in the host, spores germinate into rapidly growing vegetative cells elaborating toxins. When animals die of anthrax, vegetative bacteria sporulate upon nutrient limitation in the carcass or soil while in the presence of air. After release into the soil environment, spores form a localized infectious zone (LIZ) at and around the carcass. Laboratory strains of B. anthracis produce fewer proteins associated with growth and sporulation compared to wild strains isolated from recent zoonotic disease events. We verified wild strains grow more rapidly than lab strains demonstrating a greater responsiveness to nutrient availability. Sporulation was significantly more rapid in these wild strains compared to lab strains, indicating wild strains are able to sporulate faster due to nutrient limitation while laboratory strains have a decrease in the speed at which they utilize nutrients and an increase in time to sporulation. These findings have implications for disease control at the LIZ as well as on the infectious cycle of this dangerous zoonotic pathogen.

Assessment of Myocardial Viability in Persistent Defects on Thallium-201 SPECT after Reinjection Using Gradient-Echo MRI

This prospective study assessed myocardial viability in 30 patients with coronary heart disease and persistent defects despite reinjection on TI-201 single-photon computed tomography (SPECT). In each patient, three observers graded TI-201 uptake in 7 left ventricular wall segments. Gradient-echo magnetic resonance imaging in the region of the persistent defect generated 12 to 16 short axis views representing a cardiac cycle. A total of 120 segments were analyzed. Mean end-diastolic wall thickness and systolic wall thickening (± SD) was 11.5 ± 2.7 mm and 5.8 ± 3.9 mm in 48 segments with normal TI-201 uptake, 10.1 ± 3.4 mm and 3.7 ± 3.1 mm in 31 with reversible lesions, 11.3 ± 2.8 mm and 3.3 ± 1.9 mm in 10 with mild persistent defects, 9.2 ± 2.9 mm and 3.2 ±2.2 mm in 15 with moderate persistent defects, 5.8 ± 1.7 mm and 1.3 ± 1.4 mm in 16 with severe persistent defects, respectively. Significant differences in mean end-diastolic wall thickness (p <0.0005) and systolic wall thickening (p <0.005) were found only between segments with severe persistent defects and all other groups, but not among the other groups. On follow-up in 11 patients after revascularization, 6 segments with mild-to-moderate persistent defects showed improvement in mean systolic wall thickening that was not seen in 6 other segments with severe persistent defects. These data indicate that most myocardial segments with mild and moderate persistent TI-201 defects after reinjection still contain viable tissue. Segments with severe persistent defects, however, represent predominantly nonviable myocardium without contractile function.

Fusion of laboratory and textual data for investigative bioforensics

Chemical and biological forensic programs focus on the identification of a threat and acquisition of laboratory measurements to determine how a threat agent may have been produced. However, to generate investigative leads, it might also be useful to identify institutions where the same agent has been produced by the same or a very similar process, since the producer of the agent may have learned methods at a university or similar institution. We have developed a Bayesian network framework that fuses hard and soft data sources to assign probability to production practices. It combines the results of laboratory measurements with an automatic text reader to scan scientific literature and rank institutions that had published papers on the agent of interest in order of the probability that the institution has the capability to generate the sample of interest based on laboratory data. We demonstrate the Bayesian network on an example case from microbial forensics, predicting the methods used to produce Bacillus anthracis spores based on mass spectrometric measurements and identifying institutions that have a history of growing Bacillus spores using the same or highly similar methods. We illustrate that the network model can assign a higher posterior probability than expected by random chance to appropriate institutions when trained using only a small set of manually analyzed documents. This is the first example of an automated methodology to integrate experimental and textual data for the purpose of investigative forensics.

Bayesian integration of isotope ratio for geographic sourcing of castor beans

Recent years have seen an increase in the forensic interest associated with the poison ricin, which is extracted from the seeds of the Ricinus communis plant. Both light element (C, N, O, and H) and strontium (Sr) isotope ratios have previously been used to associate organic material with geographic regions of origin. We present a Bayesian integration methodology that can more accurately predict the region of origin for a castor bean than individual models developed independently for light element stable isotopes or Sr isotope ratios. Our results demonstrate a clear improvement in the ability to correctly classify regions based on the integrated model with a class accuracy of 60.9 ± 2.1% versus 55.9 ± 2.1% and 40.2 ± 1.8% for the light element and strontium (Sr) isotope ratios, respectively. In addition, we show graphically the strengths and weaknesses of each dataset in respect to class prediction and how the integration of these datasets strengthens the overall model.

A capillary absorption spectrometer for stable carbon isotope ratio (13C∕12C) analysis in very small samples

A capillary absorption spectrometer (CAS) suitable for IR laser isotope analysis of small CO(2) samples is presented. The system employs a continuous-wave (cw) quantum cascade laser to study nearly adjacent rovibrational transitions of different isotopologues of CO(2) near 2307 cm(-1) (4.34 μm). This initial CAS system can achieve relative isotopic precision of about 10 ppm (13)C, or ∼1 per thousand (per mil in delta notation relative to Vienna Pee Dee Belemnite) with 20-100 picomoles of entrained sample within the hollow waveguide for CO(2) concentrations ∼400-750 ppm. Isotopic analyses of such gas fills in a 1-mm ID hollow waveguide of 0.8 m overall physical path length can be carried out down to ∼2 Torr. Overall (13)C∕(12)C ratios can be calibrated to ∼2 per thousand accuracy with diluted CO(2) standards. A novel, low-cost method to reduce cw-fringing noise resulting from multipath distortions in the hollow waveguide is presented, which allows weak absorbance features to be studied at the few ppm level (peak-to-rms) after 1000 scans are co-added in ∼10 s. The CAS is meant to work directly with converted CO(2) samples from a laser ablation-catalytic combustion micro-sampler to provide (13)C∕(12)C ratios of small biological isolates currently operating with spatial resolutions ∼50 μm.

Simultaneous manifestation of acute myocardial infarction and nephrotic syndrome

This report describes the simultaneous manifestation of ischemic heart disease and nephrotic syndrome in a 37-year-old woman presenting with acute anterior myocardial infarction. Symptoms of nephrotic syndrome, such as facial and peripheral edema accompanied by proteinuria and hyperlipidemia, and onset of severe retrosternal pain developed within 24 h. Coronary angiography revealed a complete thrombotic occlusion of the proximal portion of the left anterior descending artery with no evidence of arteriosclerotic lesions. Histologic examination of renal biopsy, including electron microscopy, revealed evidence of minimal change glomerulonephritis. Ultrastructural studies demonstrated widespread effacement of epithelial foot processes. Elevated levels of circulating fibrinogen appeared to be an important factor for the hypercoagulable state in this patient, suggesting a causative relationship between coronary thrombosis and nephrotic syndrome.

Superiority of combined CK-MB and troponin I measurements for the early risk stratification of unselected patients presenting with acute chest pain

BACKGROUND

Recent studies have suggested that positive troponin I tests are associated with an increased risk of cardiac death during short-term follow-up. However, it is unknown if troponin I tests alone or in addition to CK-MB measurements are superior to predict unfavorable outcome during long-term follow-up.

PATIENTS AND METHODS

In a prospective, double-blind study we assessed the prevalence and prognostic value of combined troponin I and CK-MB tests in an unselected cohort of patients (n = 292) admitted to the emergency department for acute chest discomfort. Patients were grouped according to the diagnosis on discharge in those with acute myocardial infarction (1), unstable angina (2), and noncardiac chest pain (3). Six months after enrollment, death rates were obtained and follow-up interviews were performed with respect to survival, recurrence of chest pain, and myocardial infarction.

RESULTS

In patients with evidence of coronary heart disease, the mortality rate for abnormal troponin I and normal CK-MB levels was 5.0%. Baseline troponin I and elevated CK-MB levels were associated with a mortality rate of 4.0%. However, the mortality rate was significantly higher (11.1%) in patients presenting with elevated troponin I and CK-MB values. In patients without myocardial infarction on admission, 10.5% with positive troponin I tests died compared to 1.6% with negative tests. The mortality rate in patients without myocardial infarction was 2.7% for patients with elevated CK-MB but normal troponin I values. In patients with both markers elevated a significantly higher mortality rate (16.7%) was found, representing a 6-fold increase in the death event rate. With the additional knowledge of troponin I values, it could be demonstrated that certain cases were misclassified as having noncardiac chest pain. At least some of the latter patients with above-normal values of troponin I were retrospectively to be reclassified as unstable angina. Acute non-Q-wave myocardial infarctions were occasionally misdiagnosed as either angina pectoris or nonischemic chest pain.

CONCLUSIONS

Our data suggest the superiority of combined CK-MB and troponin I measurements in clinical practice for the early risk stratification of patients presenting with acute chest pain. In nonmyocardial infarctions, both CK-MB and troponin I convey independent prognostic information with regard to fatal outcome. Troponin I tests in addition to CK-MB measurements contribute to a lower rate of misdiagnoses.

Single-laser approach for fluorescence guidance of excimer laser angioplasty at 308 nm: evaluation in vitro and during coronary angioplasty

BACKGROUND AND OBJECTIVE

Spectroscopic guidance of laser angioplasty has been attempted using a diagnostic He-Cd laser in addition to the therapeutic laser system. This study evaluated a single-laser approach for simultaneous ablation and fluorescence excitation.

STUDY DESIGN/MATERIALS AND METHODS

A spectroscopy system was coupled to a clinical XeCl excimer laser. Ablation of 162 human aortic samples in saline and blood with 45 mJ/mm2 per pulse yielded 676 fluorescence spectra validated histologically. The same equipment was used in 16 patients for angioplasty of 18 coronary stenoses applying 500 to 1,725 pulses with 45 to 60 mJ/mm2 under saline flushing. A total of 783 spectra were recorded and validated by intracoronary ultrasound (categories: atheroma, fibrous plaque, calcified lesion).

RESULTS

In vitro, 5 types of spectra could be differentiated: (1) atheroma, (2) fibrous plaque, (3) calcified lesion in saline, (4) media, and (5) calcified lesion in blood. Discriminant analysis prospectively classified 576 validation spectra with the following sensitivity and specificity for each type: (1) 83.5 and 97.1%, (2) 85.7 and 96.8% (3) 100 and 98.5%, (4) 98.1 and 99.3%, (5) 98.9 and 100%, respectively. In vivo type 1, 2, 3, and 5 spectra were also observed, but not the media spectrum. The predominant sonographic category also prevailed in spectroscopy. Calcified lesions yielded type 3 and 5 as well as mixed spectra.

CONCLUSIONS

Using an excimer laser for angioplasty allows combining ablation and fluorescence excitation without a diagnostic laser. Principal types of atherosclerotic lesions and the media can be differentiated spectroscopically with this approach.

Hypercoagulability in a patient with hypodysfibrinogenemia: implications for clinical management

Dysfibrinogenemia accounts for approximately 0.7% of thrombophilia in patients with venous thromboembolic disease. In 20% of these patients, plasma thrombophilic dysfibrinogen is below 1.0 mg/ml, defining hypodysfibrinogenemia. We describe a young female patient, in whom hypodysfibrinogenemia was the cause of several severe thromboembolic events which occurred even under oral anticoagulation monitored by a standard prothrombin time (PT) test. In this patient, the standard PT test according to Quick underestimated the plasma coagulability in vivo, presumably due to the low levels of dysfunctional fibrinogen as the substrate of the thromboplastin reagent. A PT test supplemented with bovine plasma fibrinogen (Thrombotest) revealed lower fibrinogen-independent international normalized ratio (INR) values in the proposita on oral anticoagulation compared to a control group with eufibrinogenemia. Monitoring therapy with the fibrinogen-independent Thrombotest secured safe anticoagulation in this patient. We suggest to consider PT tests with exogenous fibrinogen (e.g. Thrombotest) to monitor oral anticoagulation in the rare thrombophilic patients with hypodysfibrinogenemia.

[Experiences with temporary vena cava filters in 114 at-risk patients with thrombosis or thromboembolism]

BACKGROUND AND OBJECTIVES

The indications for temporary implantation of a vena cava filter remain unclear and there are as yet few data about its complications and reliability. It was the aim of this study to determine the efficacy and complication rate of the temporary use of a vena cava filter (VCF) in a large group of patients at high risk of pulmonary embolism, and thus contribute to defining the indications for such temporary implantation.

PATIENTS AND METHODS

Between November 1991 and October 1997 a total of 118 VCF were implanted in four groups of a total of 114 patients (67 women, 47 men; average age 45.3 +/- 19.8 [12-82] years) to prevent pulmonary embolism: those (1) with massive or fulminant pulmonary embolism (n = 54); (2) with mechanical thrombus fragmentation and (or) local catheter-delivered systemic thrombolysis in pelvic, leg or caval vein thrombosis (n = 42); (3) with systemic thrombolysis in case of floating thrombi at the femoral, iliac or caval veins (n = 7); and (4) as perioperative measure in caesarean section, venous thrombectomy, other surgical interventions or when anticoagulation had to be discontinued in patients with deep vein thrombosis (n = 11).

RESULTS

Filters remained implanted for a mean of 6.1 +/- 3.4 (1-16) days. Placement had to be corrected because of filter dislocation in eight patients. Proven pulmonary embolism occurred after filter implantation in only one patient, after filter displacement into the unthrombosed contralateral iliac vein. Thrombus deposition on the filter before its removal was demonstrated in nine patients: thrombolysis was effective in seven of them, while thrombosed filters had to be removed surgically in two. Residual thrombi were found on the filter in six further patients. No pulmonary embolism occurred in connection with filter removal. Local complications at or around the site of insertion of the introducing catheter occurred in 53 of the 114 patients (46.5%): haematoma in 42, infection in 21 and brachial vein thrombosis in three patients.

CONCLUSIONS

The rate of clinically relevant pulmonary embolism can probably be reduced to a minimum by the implantation of a temporary vena cava filter. The overall complication rate is high, but serious complications are rare.

[Practicability and clinical relevance of routine psychological screening of patients in general internal medicine units]

In medical patients, anxiety and depression are frequent but often undiagnosed problems. The aim of the present study was to test and evaluate a psychological screening in medical in-patients. Using the Hospital Anxiety and Depression Scale (HADS), we screened 454 out of 743 consecutive medical in-patients. Physical symptoms and diagnoses were also recorded. Elevated scores for anxiety and depression were found in 20.8% and 23.9%, respectively. They were relatively independent of physical findings but correlated with subjective symptoms. In a subgroup who completed the questionnaire twice, HADS scores remained constant until discharge. Cardiological patients with abnormal baseline anxiety stayed significantly longer in hospital than those who were not anxious. Over a one-year follow-up, initially depressed patients had a risk of in-hospital death that was 2.5 times higher. This effect remained stable after controlling for baseline diagnoses and indices of severity of the disease.

[The renin-angiotensin system in cardiovascular diseases]

BACKGROUND

The renin-angiotensin system is mainly involved in several cardiovascular diseases and in the pathophysiology of heart failure. It exists as a circulating and a local system which can be differently regulated. Interventions in this system by angiotensin-converting enzyme (ACE) antagonists or angiotensin-receptor antagonists slow the progression of heart failure and result in prolongation of life expectancy and improvement of hemodynamics.

MECHANISMS OF ACTION

The main underlying mechanisms are: 1. Heart failure results in activation of the renin-angiotensin system as a compensatory mechanism with elevation of circulating angiotensin II, norepinephrine and vasopressin. Antagonists of this compensatory mechanisms acutely result in improvement of the hemodynamic situation. 2. Elevated circulating and local renin-angiotensin systems cause chronic structural myocardial and vascular effects. Angiotensin-converting enzyme antagonists and angiotensin-receptor blockers modulate and partly antagonize these structural changes such as myocardial hypertrophy, myocardial fibrosis and vascular proliferative responses. Gene and receptor regulation of the system are currently not fully understood and are subject of intensive research. 3. The renin-angiotensin system is closely related to the bradykinin system and thus indirectly to nitric oxide and endothelial function. Bradykinin has multiple other effects on the hemostatic system as a well as on the myocardium and vascular system.

CONCLUSION

These complex interactions require further evaluation. Research with specific bradykinin antagonists will give new insights into this system.

Cardiac involvement in proximal myotonic myopathy

Proximal myotonic myopathy (PROMM) is a recently described autosomal dominantly inherited disorder resulting in proximal muscles weakness, myotonia, and cataracts. A few patients with cardiac involvement (sinus bradycardia, supraventricular bigeminy, conduction abnormalities) have been reported. The cases of three relatives with PROMM (weakness of neck flexors and proximal extremity muscles, calf hypertrophy, myotonia, cataracts) are reported: a 54 year old man, his 73 year old mother, and 66 year old aunt. All three presented with conduction abnormalities and one had repeated, life threatening, sustained monomorphic ventricular tachycardia. This illustrates that severe cardiac involvement may occur in PROMM.

Coxsackievirus genome in myocardium of patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy

Enteroviruses are known as major infectious agents for inflammatory heart diseases such as myocarditis and dilated cardiomyopathy (DCM). Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVC) is characterized by replacement of right ventricular myocardium by fatty and fibrous tissue. In about 65% of patients inflammatory infiltrates suggest an inflammatory or infectious etiopathogenesis. To test this hypothesis, we investigated endomyocardial biopsies of patients with ARVC, with myocarditis or DCM, and from patients with non-inflammatory cardiac disorders for the presence of enteroviral genome. Enteroviral RNA with homology to coxsackieviruses type B was detected in 3 of 8 patients with ARVC (37.5%), in 7 of 23 patients with myocarditis or DCM (30.4%), but in none of 5 patient with non-infectious myocardial diseases (p < 0.05 compared to ARVC patients). These results support earlier suggestions that coxsackievirus infection of the myocardium is possibly related to the pathogenesis of ARVC.

[Age related decrease of high density lipoproteins (HDL) in women after menopause. Quantification of HDL with genetically determined HDL arylesterase in women with healthy coronary vessels and in women with angiographically verified coronary heart disease]

BACKGROUND

The decline in the concentration of high density lipoproteins (HDL) observed in postmenopausal women is thought to contribute to the increasing incidence of coronary artery disease (CAD) after menopause. Human serum arylesterase (EC 3.1.1.2) is exclusively associated with HDL. We therefore investigated possible differences in the decline of HDL-levels and of HDL-subfractions HDL2 and HDL3 between postmenopausal women without and with angiographically documented CAD.

PATIENTS AND METHODS

HDL-, HDL2-and-HDL3- concentrations were studied in postmenopausal women with angiographically documented CAD (n = 24; 51 to 72 years mean: 62 years) and compared to HDL-parameters of women without CAD (n = 22; 51 to 81 years, mean: 58 years). Arylesterase activities of HDL2-and HDL3-subfractions and HDL2-cholesterol concentrations were determined after differential precipitation with polyethylene glycol (4.7 mM PEG). Phenotyping of HDL-arylesterase was achieved in CAD patients and in women without CAD after determining hydrolysis of arylesterase substrates paraoxon (PO) and phenylacetate (PA) by calculating paraoxonase/arylesterase activity ratios R (R = [PO]/[PA] x 1000): phenotype A (n = 26) with R < 2.5, phenotype AB (n = 16) with 5.0 < R < 10.7, and phenotype B (n = 4) with R > 13.5.

RESULTS

In postmenopausal women with documented CAD, as compared to women without CAD, HDL-cholesterol (55 +/- 3 mg/dl vs. 69 +/- 3 mg/dl HDL2-arylesterase (25 +/- 1 kU/l vs. 33 +/- 2 kU/l), and HDL3-arylesterase (89 +/- 4 kU/l vs. 106 +/- 5 kU/I) were found to be significantly reduced. Analysis of the correlation of lipid parameters and age revealed in CAD patients, but not in postmenopausal women without CAD, a significant increase of total cholesterol (r = 0.42), and significant reductions of both HDL2-arylesterase (r = -0.47) and HDL3-arylesterase (r = 0.74) with increasing age. In contrast, HDL-cholesterol (r = -0.14) and HDL2-cholesterol (r = -0.06) of CAD patients showed only slight and non-significant reductions with age. Since HDL3-arylesterase was found to be age-dependently reduced in women without CAD (r = 0.17), HDL2-arylesterase of postmenopausal women, among all lipid parameters showed the most pronounced differences between women without CAD and CAD patients. The age-dependent decrease of HDL2-arylesterase in postmenopausal women with CAD does not result from an increased frequency of B-allele carriers in the subgroup of CAD patients with an age above the median (64 years).

CONCLUSION

Genetically determined serum HDL-arylesterase is well suited to quantify HDL in postmenopausal women without and with CAD. HDL2-arylesterase of postmenopausal women should be evaluated as a screening parameter for both primary and secondary CAD prevention.

Nocturnal oxygen and hypercapnic ventilatory response in patients with congestive heart failure

Patients with congestive heart failure and Cheyne-Stokes respiration have a low arterial oxygen saturation, especially during sleep, which can be increased by breathing oxygen. Chronic alterations in blood gases are known to modulate the hypercapnic ventilatory response (HCVR). We therefore evaluated whether the HCVR is influenced by nocturnal nasal oxygen in patients with heart failure and Cheyne-Stokes respiration. Twenty patients with chronic congestive heart failure and a left ventricular ejection fraction < or = 35% (mean 18.3% +/- SD 6.0%) as well as 25 healthy control subjects were studied. The patients were assigned to 1 week each of nocturnal nasal oxygen and room air with a flow of 41 min-1 in a randomized cross-over fashion. After each week resting ventilation and HCVR were evaluated by the rebreathing technique. Breathing oxygen during the night for 1 week increased the basal nocturnal oxygen saturation from 92.5% +/- 1.6% to 96.5% +/- 0.9% (P < 0.000,01) and reduced Cheyne-Stokes respiration. HCVR was 1.22 +/- 0.90 l min-1 mmHg-1 after nocturnal room air and did not differ from that in the control subjects (1.31 +/- 0.62 l min-1 mmHg-1). In the patients HCVR decreased to 0.91 +/- 0.52 l min-1 mmHg-1 after nocturnal oxygen (P = 0.019). There were no significant changes with nocturnal oxygen in resting minute ventilation, respiratory rate or end-tidal PCO2. We conclude that nocturnal nasal oxygen reduces HCVR in patients with congestive heart failure and Cheyne-Stokes respiration.

Complications of intra-aortic balloon counterpulsation. The role of catheter size and duration of support in a multivariate analysis of risk

AIMS

The aim of this study was to assess the risk of intra-aortic balloon counterpulsation and to identify clinical and procedural variables that would predict complications.

METHODS AND RESULTS

We analysed 381 consecutive patients who were treated between 1977 and 1995 at our catheterization laboratory and/or medical intensive care unit. The complications considered relevant were limb ischaemia requiring catheter removal, vascular injury, bleeding requiring transfusion, embolic events, and infection. In eight patients the balloon could not be inserted. The rate of complications for the remaining 373 patients was 12.9%. Between 1977 and 1980, surgical insertion was performed using a 12 French catheter with a complication rate of 30.4% (seven of 23 patients). Percutaneous implantation, performed after 1981, had an overall complication rate of 11.7% (41 of 350 patients). Using thinner catheters for percutaneous placement was associated with a reduction in the rate of complications, from 20.7% (17 of 82 patients) for 12 French catheters to 9.9% (10 of 101 patients) for 10.5 French catheters (P = 0.04), and 8.4% (14 of 167 patients) for 9.5 French catheters (P = 0.006). Multivariate logistic regression analysis identified duration of counterpulsation > 48 h (odds ratio 3.6), catheter size (odds ratio 3.4 for 12 French catheters), peripheral vascular disease (odds ratio 2.7), and shock (odds ratio 2.0) as independent risk factors for counterpulsation-associated complications. When considering 9.5 French catheters only (167 patients, all after 1992), the sole remaining independent risk factor was duration of counterpulsation > 48 h (odds ratio 3.8). Those patients with 9.5 French catheters in whom counterpulsation did not exceed 48 h had a low complication rate of 3.9%.

CONCLUSION

The rate of percutaneous intra-aortic balloon counterpulsation complications was thus significantly reduced by employing thinner catheters. It was at an acceptable level for 9.5 French catheters, where a long duration of counterpulsation emerged as the most significant factor associated with complications. Whether using even thinner catheters in combination with a sheathless implantation technique further minimizes the risk of counterpulsation remains to be seen.

Monocyte activation in congestive heart failure due to coronary artery disease and idiopathic dilated cardiomyopathy

OBJECTIVE

To investigate plasma tumor necrosis factor (TNF)alpha, tumor necrosis factor alpha soluble receptor I, interleukin-1beta and neopterin concentrations as markers of monocyte activation in patients with heart failure.

STUDY DESIGN

The group consisted of patients with heart failure due to dilated cardiomyopathy (n=19) and coronary artery disease (n=11). Patients without cardiac failure served as controls (n=10).

RESULTS

TNFalpha concentrations were elevated only in heart failure patients with coronary artery disease (2.9+/-0.3 pg/ml versus 1.7+/-0.3 pg/ml; P<0.05). When the patients were grouped according to acute and chronic failure, TNFalpha concentrations were significantly elevated in acute failure (3.1+/-0.4 pg/ml, n=6 versus 1.7+/-0.2 pg/ml, n=8; P<0.05). TNFalpha concentrations were elevated in patients with coronary artery disease and chronic heart failure compared to coronary artery disease patients without failure (2.0+/-0.4 pg/ml, n=6 versus 1.8+/-0.3 pg/ml, n=7; P<0.05). A higher proportion of patients with myocardial insufficiency showed increased lipopolysaccharide-inducible TNFalpha concentrations (10/30 versus 0/9, P<0.05).

CONCLUSIONS

TNFalpha is elevated in patients with acute cardiac decompensation. Among patients with chronic heart failure only those with coronary artery disease exhibit increased levels. Cytokine concentrations are similar in heart failure due to dilated cardiomyopathy and coronary artery disease. Monocytes of patients suffering from cardiac insufficiency show an increased sensitivity towards stimuli such as lipopolysaccharides.

Risk factors for acute and subacute stent thrombosis after high-pressure stent implantation: a study by intracoronary ultrasound

BACKGROUND

In the era of coronary stenting with high-pressure expansion, stent thrombosis remains a major life-threatening risk. Because of its superior imaging mode, intracoronary ultrasound could provide insight into potential risk factors for stent thrombosis.

PATIENTS AND METHODS

In 215 patients with stent implantations controlled by intracoronary ultrasound, four occurrences of subacute stent thrombosis, two complete acute thrombotic occlusions, and four occurrences of incomplete acute thrombosis were observed. All stents were expanded with inflation pressures of at least 14 atm ( 17+/-3 atm). The clinical data and the qualitative and quantitative ultrasound information were compared between stents with thrombosis and stents without thrombosis. The luminal area and the plaque border of the reference segments, and of the smallest and largest site of the stented segment after the initial and final expansion, were measured.

RESULTS

Stents in the left anterior descending artery were more often involved in stent thrombosis than other vessels, but the vessel dimensions in this target vessel were smaller than in the right coronary artery. The plaque burden was considerably larger after stent implantation with subsequent thrombosis compared with no thrombosis (74.1+/-8.8% vs 63.6+/-8.0%; p < 0.001), and the stent area was smaller (4.80%+/-1.33 mm2 vs 6.86+/-2.08 mm2; p < 0.01 ). In stents with thrombosis the plaque burden of the stent site with the smallest and largest lumen differed by 15.2%, whereas the difference in plaque burden in stents without thrombosis was 2.7%. Intracoronary ultrasound showed that the best risk predictor of thrombosis was the residual plaque burden of the stented segment (odds ratio 15.7 [confidence interval 2.4 to 104.7]), and a small stent area after implantation (odds ratio 6.8 [confidence interval 1.9 to 24.3]).

CONCLUSION

In a multivariate risk analysis plaque burden was the strongest independent risk factor for stent thrombosis. The amount of residual plaque mass around the stent might be a potential trigger for thrombus formation.

Empirical versus tested antitachycardia pacing in implantable cardioverter defibrillators: a prospective study including 200 patients

BACKGROUND

Implantable cardioverter-defibrillators (ICDs) reduce the risk of sudden cardiac death. The objective of this study was to evaluate whether testing of antitachycardia pacing (ATP) for induced ventricular tachycardias (VTs) at predischarge examination can predict ATP success during follow-up.

METHODS AND RESULTS

The study covers 200 consecutive patients who received ICD implants from June 1991 through December 1995. All underwent electrophysiological testing. In 54 patients (ATP tested, group T), ATP terminated induced VTs successfully. In 146 patients (empirically programmed ATP, group E), only ventricular fibrillation could be induced, including 18 with unsuccessful ATP attempts for induced VTs. Disregarding the results of ATP testing, the same ATP scheme was programmed in all patients: three attempts of autodecremental ramp with 81% of the VT cycle length, with 8 to 10 pulses. During a follow-up of 20.4 +/- 10 months, 95% of 3819 spontaneous VTs were successfully terminated with ATP in 42 patients of group T. In group E, 90% of 1346 spontaneous VTs in 81 patients were terminated with ATP. Acceleration after ATP occurred in 2% in group T versus 5% in group E. The success for all episodes in individual patients was > or =90% in >60% of the ATP tested and empirically programmed patients.

CONCLUSIONS

The results of this 200-patient prospective study comparing tested versus empirical ATP show high success (95% versus 90%) for VT termination, with low rates of acceleration. ATP is safe and very effective and should be programmed "on" in all patients regardless of the predischarge EP inducibility.

Complete morphologic and functional resolution of endocarditis of a Toronto stentless porcine bioprosthesis: a study by serial transesophageal echocardiography

Prosthetic valve endocarditis is a serious complication after valve replacement with an incidence of 0.8% for both mechanical and bioprosthetic valves. The new Toronto stentless porcine valve (SPV) for aortic replacement offers promising early results in hemodynamics and a low incidence of valve-related complications. The yearly incidence of bacterial endocarditis was reported to be 1% to 1.5%. Though complications such as a perivalvular abscess or anular dehiscence require immediate surgery, a conservative management of infective endocarditis may be possible in carefully selected cases. This is the case of a patient with late prosthetic valve endocarditis of a Toronto SPV bioprosthesis, who, in spite of large vegetations on all three valve cusps, responded well to conservative treatment. This response was monitored through repeated transesophageal echocardiographic studies (TEE), which documented complete functional recovery of the valve.

[Intracoronary ultrasound during recanalization of chronic coronary occlusions: Relation to restenosis and reocclusion after balloon angioplasty or stent implantation]

Chronic coronary occlusions carry a high recurrence rate, and coronary stenting evolves as a preferred therapy of these complex lesions. Insight into the morphology of the occluded segment by intracoronary ultrasound may provide information which may help to improve the interventional strategy and the long-term outcome. After successful recanalization of chronic coronary occlusions (4 weeks to 33 months; median 3.2 months) in 59 patients, 29 patients were treated by balloon angioplasty alone, and 30 patients received one or more coronary stents because of complicated dissections or a high-grade residual stenosis after balloon dilatation. Intracoronary ultrasound was used to assess the lesion morphology and to quantify the angioplasty result. The luminal area, the total vessel area and the extent of the plaque burden were measured proximal and distal to the occlusion and at the narrowest site within the occlusion or the coronary stents, and the elastic recoil was calculated. Plaques in chronic occlusions were predominantly hypodense, and 44% were characterized by a multilayered plaque appearance. The elastic recoil was higher in multilayered plaques than in other plaques (46 +/- 19% vs. 34 +/- 15%; p < 0.05). Based on the quantitative ultrasound measurement after the initial balloon dilatation, it appeared that the initial balloon was undersized in 54%. The lumen area in patients with balloon angioplasty alone was increased from 4.02 +/- 1.34 mm2 to 5.49 +/- 1.47 mm2 and in the stented patients from 3.58 +/- 1.04 mm2 to 7.10 +/- 1.92 mm2. The recurrence rate in patients with balloon angioplasty was 48% with 24% reocclusions. Patients with recurrence had a slightly lower lesion area (3.97 +/- 1.41 mm2 vs. 4.71 +/- 1.44 mm2; n.s.) and minimum diameter (1.82 +/- 0.31 mm vs. 2.14 +/- 0.40 mm; p < 0.05) after dilatation. In stented patients the recurrence rate was 27% with two early stent thrombosis (6.7%) and no late reocclusion. In patients with recurrence the achieved stent area was significantly smaller than in those without restenosis (5.71 +/- 0.90 mm2 vs. 7.59 +/- 1.96 mm2; p < 0.01), and the degree of vascular remodelling at the site of the occlusion was less pronounced. Intracoronary ultrasound showed sonographic plaque characteristics in chronic occlusions which responded poorly to balloon dilatation alone. Stent implantation improved considerably the luminal area gain and could reduce the long-term outcome. To further improve the recurrence rate in stents, an optimized stent expansion should be achieved, and intracoronary ultrasound could provide an ideal tool for this purpose.

[Cheyne-Stokes respiration in patients with congestive heart failure]

Cheyne-Stokes respiration (CSR) during sleep is common in patients with severe congestive heart failure induces repetitive oxygen desaturation with arousals, and impairs sleep. This causes daytime symptoms and likely an increase in sympathetic activity. It has, therefore, been suggested that CSR is independently related to mortality. The major mechanisms behind CSR include reduced body stores of oxygen, a low apneic threshold for carbon dioxide, prolonged circulation time between the lung and the carotid body, and disturbance of respiratory control due to arousals. It is apparent that the main task in treating CSR is the therapy of congestive heart failure. Indeed, diuretics to treat pulmonary congestion as well as ACE-inhibitors reduce CSR. Recently, theophylline (an antagonist of the ventilatory depressant adenosine) was shown to reduce CSR and oxygen-desaturation. Continuous positive airway pressure did improve CSR but not sleep and may reduce cardiac output in a subgroup of patients with heart failure. Nocturnal oxygen reduces CSR and improves exercise tolerance as well as sleep. This and its apparent safety makes oxygen an appropriate treatment for nocturnal CSR. Whether successful treatment of nocturnal CSR has any impact on the natural course of heart failure needs to be determined in further studies.

Morphology of chronic coronary occlusions and response to interventional therapy--a study by intracoronary ultrasound

OBJECTIVES

Balloon angioplasty of chronic coronary occlusions has a low procedural success and a high recurrence rate. Better tomographic insights into the lesion morphology may improve the interventional strategy and results.

METHODS

Intracoronary ultrasound was used during the recanalizaton procedure of 45 chronic coronary occlusions (2 weeks to 14 months; average 3.4 months) to determine the lesion morphology and to assess the angioplasty result. The luminal area and the plaque burden were measured proximal and distal to the occlusion, and within the occlusion. The ultrasonographic characteristics of the occlusive lesions were compared to 45 nonocclusive lesions of age-matched patients with stable angina pectoris.

RESULTS

Occlusive lesions were more often echodense as compared to nonocclusive lesions (35% vs. 20%; p = 0.10). In chronic occlusions a multi-layered plaque morphology was observed in 22%, and this morphology was not found in nonocclusive lesions. Angiographic characteristics were not related to the ultrasonographic morphology of the lesion. Despite similar vessel areas in occlusive and nonocclusive lesions, the balloon size selected according to the angiographic image was underestimated in occlusive lesions. Based on the quantitative ultrasound measurement the balloon size was increased from 2.6 +/- 0.3 mm to 3.3 +/- 0.5 mm in 53% of the lesions. This resulted in an increase of the luminal area from 3.51 +/- 0.92 to 5.08 +/- 1.43 mm2 (p < 0.001). The acute recoil after balloon angioplasty was similar (34 +/- 18%) in hypodense and echodense plaques, but was significantly higher in lesions with a multi-layered plaque morphology (49 +/- 22%; p < 0.05). In 19 patients with severe dissections or extreme acute recoil (residual stenosis > 50%) the use of a stent increased the luminal area from 3.94 +/- 0.81 to 7.51 +/- 1.71 mm2 (p < 0.001).

CONCLUSIONS

Intracoronary ultrasound demonstrated a multi-layered plaque morphology in one fourth of the chronic occlusions. This type of plaque was associated with a significant acute recoil. The presence of diffuse atherosclerosis in neighbouring segments of chronic coronary occlusions leads to underestimation of the balloon size. Quantitative assessment by intracoronary ultrasound helped to optimize the balloon size leading to a significant luminal area gain. The detection of excessive acute recoil should be considered an indication for stent deployment.

[Embolic complications in bacterial endocarditis]

Embolic complications are a major prognostic determinant in the clinical course of infective endocarditis (IE) with an incidence of about 30-50%. In order to analyze risk factors leading to embolism in native (NVE) and prosthetic valve endocarditis (PVE), we reviewed 177 consecutive patients; 43% were female, 57% male, PVE occurred in 24% of all patients all left-sided, among the NVE were 11% right-sided IE. Major embolic complications occurred in 40% of all patients. In NVE, a higher rate of embolic events (45% vs. 26%; p < 0.05), and a larger vegetation size compared to PVE was observed (14 +/- 6 mm vs. 11 +/- 5 mm; p < 0.05). The most important risk factor for embolic complications in NVE was Staphylococcus aureus (odds ratio 6.4). Furthermore, double valve endocarditis, fever, and mitral valve endocarditis were associated with the risk for embolism. In case of severe regurgitation the rate of embolic complications was reduced (54% vs. 77%; p < 0.05). In PVE, fever was a risk factor for embolic events. Staphylococcus aureus was also a frequent microorganism in embolism (45% vs. 22%). The in-hospital mortality was significantly increased in case of embolism (NVE 40% vs. 11%; p < 0.001; PVE 36% vs. 9% p < 0.05). About 50% of all embolic events occurred before admission. In NVE, due to high in-hospital mortality, the rate of patients with embolism undergoing surgery was lower (57% vs. 72%; p < 0.05); whereas in PVE no significant difference was observed. In patients with NVE, aspirin therapy because of coronary artery disease appeared to reduce the rate of embolic complications (11% vs. 47%). However, the low number of patients on aspirin (9%) does not allow recommendations regarding a potential benefit. In conclusion, identification of risk factors leading to embolism in IE may be useful in considering early surgical therapy. However, the high rate of embolic complications before hospital admission indicates a need for improving the diagnostic delay in the prehospital phase.

Evaluation of an active coronary perfusion balloon device using Doppler flow wire during PTCA

The aim of this study was to assess whether active coronary perfusion catheters (APC) can provide a sufficient coronary flow in large caliber vessels during balloon inflation. To prevent myocardial ischemia during PTCA, these APC may be employed. However, it is as yet unknown whether the active flow rate of these devices approaches the flow rate prior to PTCA during balloon inflation. Therefore, we measured the efficacy of the APC during balloon inflation in vessels supplying a large amount of myocardium. In 12 patients (1 female, 11 males, 53 +/- 12.6 yr) with stenosed vessels (average diameter 3.4 +/- 0.26 mm), the coronary flow velocity was measured using a 0.014" Doppler guidewire, which was placed distally bypassing the balloon of the APC. The active perfusion balloon catheter was advanced through a 7F guiding catheter along a 0.014" guidewire. After removal of the guidewire, arterial blood being withdrawn from the side port of the femoral angioplasty sheath was pumped through the catheter to the distal coronary vessel. The perfusion volumes of the pump were set to different levels between 30 to 60 ml/min. Intracoronary flow rate was calculated by the angiographically assessed vessel luminal area [symbol: see text] average peak velocity [symbol: see text] 0.5. The mean coronary flow rate prior to PTCA was 43 +/- 17.7 ml/min. Maximum flow during PTCA was 55 +/- 19.6 ml/min. We found a good correlation between the preset external pump rate and the coronary flow in situ (r = 0.92). Pre-PTCA flow rates were achieved in 11 of 12 patients (92%) during balloon inflation. No relevant decrease in the arterial pressure occurred during dilation times of 4.6 +/- 1.63 min. Only two patients showed significant ECG changes during these balloon inflations. After an average follow-up period of 13 +/- 6.3 mo, only one patient (8%) had a significant re-stenosis requiring the implantation of a stent. The combination of intravascular Doppler velocity measurements with quantitative coronary angiography offers the opportunity of exact online flow registration during angioplasty. Using APC, It is possible to maintain a sufficient coronary flow in the distal vessel during balloon inflation even in large vessels. Therefore, as compared with mechanical circulatory assist devices, coronary assist by APC is a little invasive, but according to our measurements it might be a sufficient tool for performing PTCA also in high-risk patients.

Additional luminal area gain by intravascular ultrasound guidance after coronary stent implantation with high inflation pressure

AIMS

Studies by intravascular ultrasound demonstrated inadequate expansion in a large number of stents, which lead to the increase of inflation pressure for stenting. The present study examined whether routine use of high-pressure inflation would be sufficient for an optimum stent expansion without sonographic guidance.

METHODS AND RESULTS

Two types of single coronary stents (Palmaz-Schatz in 54, and Wiktor in 25) were implanted with inflation pressures of 16-20 atm in 79 nonocclusive coronary lesions. IVUS before stenting was used in 78% to select the adequate stent size. Intravascular ultrasound after stenting was used to asses the minimum stent are and diameter, the reference areas, and the strut apposition to the vessel wall. The difference between the area of the expanding balloon and the stent area was calculated as the luminal deficit of the stent. Completeness of stent expansion required full strut apposition and lesion coverage, and a minimum stent area that was larger than the distal reference, and larger than 60% of the proximal reference. Intravascular ultrasound before stenting lead to an increase of the stent size in 47%. After high-pressure expansion, even with the optimized balloon size, 8% of stents had struts protruding into the lumen. The stent area (6.87 +/- 1.93 mm2) was significantly smaller than both the proximal (9.59 +/- 2.91 mm2; p < 0.001) and distal reference area (8.23 +/- 3.03 mm2; p < 0.001). The criteria for complete expansion were met in 48%. The expansion with a larger high-pressure balloon in 28 stents lead to an increase of the stent area by 19% (8.19 +/- 2.24; p < 0.001), and full stent apposition in all cases. The criteria of stent expansion were met in 82%. A wide range of the luminal deficit upto 48% was observed, which was not related to sonographic lesion characteristics, except in lesions with complete circumferential calcifications. The different stent designs were characterized by a slightly lower luminal deficit in slotted-tube stents (23 +/- 13% vs. 28 +/- 12%; p = 0.11) and a better index of stent symmetry as compared with the coil stent (0.87 +/- 0.08 vs. 0.82 +/- 0.09; p < 0.05).

CONCLUSION

Routine use of high-pressure stent expansion did not lead to a sufficient stent expansion, even when the initial stent size had been guided by intravascular ultrasound. Further stent dilatation with larger balloons under ultrasound guidance would be required to optimize the luminal area gain.

Inhibition of the voltage-dependent calcium current by extracellular ATP in hamster ventricular cardiomyocytes

The modulation of the high-voltage-activated calcium current (ICa) by external ATP was examined in single ventricular cardiomyocytes of the hamster using the whole-cell configuration of the patch-clamp technique. Extracellular application of ATP (0.1-100 microM) was found to inhibit ICa reversibly. The inhibition followed a slow time course (half time approximately 25 s) and was accompanied by very small changes of the holding current and no shift in the current-voltage relationship. With 100 microM ATP, peak ICa was reduced by approximately 30%. This response was not blocked by the P1 inhibitor 8-cyclopentyl-1,3-dipropylxanthine. The nonhydrolyzable ATP analogs adenosine 5'-O-(3-thiotriphosphate) and AMP-adenosine 5'-[beta,gamma-imido]triphosphate also reduced ICa. The ATP analog alpha,beta-methylene-ATP was about equipotent with ATP at 50 microM. Internal guanosine 5'-O-(3-thiotriphosphate) (200 microM) rendered the ATP-mediated inhibition of ICa poorly reversible, whereas internal guanosine 5'-O-(2-thiodiphosphate) (200-500 microM) had no effect. Holding the intracellular adenosine 3',5'-cyclic monophosphate concentration at a constant high level did not alter the ATP response. We conclude that external ATP inhibits ICa via a P2 purinergic receptor in hamster ventricular myocytes. Our results suggest the involvement of a G protein not coupled to adenylate cyclase. The inhibition of ICa by extracellular ATP might have pathophysiological relevance under conditions of myocardial injury.

[Development and evaluation of a spectroscopy system for classification of laser-induced arterial fluorescence spectra]

The present study evaluated the potential of fluorescence guidance of laser angioplasty without using a second laser for fluorescence excitation. A prototype spectroscopy system with a grating spectrograph, microchannel plate, CCD array and digital image processor on a personal computer was developed and coupled to a clinical XeCl excimer laser. Using multifibre catheters, specimens of human aorta were ablated in physiological saline and blood. The spectra thus generated were recorded and validated histologically. Five types of spectra could be differentiated. Based on a training set, classification algorithms were developed using multiple linear regression and linear discriminant analysis with intensity ratios as predictor variables. Discriminant analysis yielded prospective classification of the remaining validation spectra with high sensitivity and specificity for each type. These data demonstrate that fluorescence spectroscopy during excimer laser ablation at 308 nm does not require a diagnostic laser. Principal types of atherosclerotic lesions and the media can be differentiated spectroscopically in physiological saline and blood.

Vasodilation by urapidil in the treatment of chronic congestive heart failure in addition to angiotensin-converting enzyme inhibitors is not beneficial: results of a placebo-controlled, double-blind study

BACKGROUND

The therapeutic benefit of an angiotensin-converting enzyme (ACE) inhibitor in combination with a different type of vasodilator is unknown.

METHODS AND RESULTS

To evaluate the effects of a combined therapy on quality of life, exercise tolerance, and hemodynamic parameters, patients with severe heart failure (New York Heart Association classes III and IV, ejection fraction below 35%) who were on ACE inhibitor therapy were randomly assigned to additional double-blind treatment with urapidil (60-120 mg/d) or placebo for 12 weeks. After enrollment of 36 patients, the study was terminated early because no beneficial effects on exercise tolerance and hemodynamic parameters could be shown for the urapidil treatment, and a trend toward increased mortality of the urapidil group was observed (odds ratio, 4.92 [0.49-49.6]; P = .167).

CONCLUSION

The combination of urapidil with an ACE inhibitor in the treatment of severe chronic congestive heart failure does not seem to offer any advantages over therapy with an ACE inhibitor alone and may have potentially harmful effects.

Causes of failed angioplasty for acute myocardial infarction assessed by intravascular ultrasound

Coronary angioplasty is gaining increased importance as a primary treatment of acute myocardial infarction, but the complication rate of the procedure is higher than in stable coronary artery disease. In a consecutive series of 110 coronary angioplasties in patients with acute myocardial infarction, the cause of initially failed procedures was studied by intravascular ultrasound. The balloon angioplasty was immediately successful in 66%. In those cases with crossing of the lesion but a dissatisfying dilatation result (persistent occlusion, reocclusion, or dissection) an intravascular ultrasound probe could be advanced to 32 of 34 lesions. The information provided by ultrasound guided the subsequent bailout therapy. Persistent occlusions were caused by extensive thrombosis in 4.5% of all cases, subsequently treated by local thrombolysis for 12 to 16 hours, and in 1.8% by a ruptured plaque, which was treated by stenting. In cases with Thrombolysis in Myocardial Infarction (TIMI) flow II, angiography suggested a thrombus in 9.1%, but intravascular ultrasound could detect dissections instead of a thrombus in half the cases. In cases of dissection, stenting was performed. Dissections were observed by angiography in 15.5%, and all cases were confirmed by ultrasound. In vessels >2.5 mm the dissection was treated by stenting. Overall, in 20 of 21 lesions stents were successfully implanted. No stent thrombosis was observed. With the assistance of intravascular ultrasound during bailout therapy, the success of coronary angioplasty to achieve TIMI flow III without residual stenosis in an unselected consecutive patient cohort with acute myocardial infarction was 96%. In direct angioplasty for acute myocardial infarction the procedure is frequently complicated by events such as plaque rupture and extensive vascular thrombosis, which are uncommon in coronary angioplasty for stable angina. Intravascular ultrasound provided insight into the underlying morphologic characteristics of failed angioplasty that enhanced the information provided by coronary angiography and assisted in the selection of the bailout therapy.

Giant cell myocarditis due to coxsackie B2 virus infection

Giant cell myocarditis is a rare disorder characterized by the histologic hallmark of diffuse inflammatory infiltrates with the appearance of multinucleated giant cells. We report on a 52-year-old man who died of rapidly progressive cardiogenic shock due to giant cell myocarditis. Serological and immunoblotting techniques revealed a myocardial infection with coxsackie B2 virus, suggesting a viral etiology of this disease. Here we present evidence for the involvement of autoimmune responses to the myocardium as numerous cardiomyocytes exhibited deposits of cell-adherent immunoglobulins. Although other causative factors may initiate giant cell myocarditis as well, our case suggests coxsackie B2 virus as one etiologic agent capable of triggering autoimmune reactions to altered heart tissue.

Mipafox differential inhibition assay for heart muscle cholinesterases: substrate specificity and inhibition of three isoenzymes by physostigmine and quinidine

1. A differential inhibition assay was developed for the quantitative determination of cholinesterase isoenzymes acetylcholinesterase (AChE; EC 3.1.1.7), cholinesterase (BChE; EC 3.1.1.8), and atypical cholinesterase in small samples of left ventricular porcine heart muscle. 2. The assay is based on kinetic analysis of irreversible cholinesterase inhibition by the organophosphorus compound N,N'-di-isopropylphosphorodiamidic fluoride (mipafox). With acetylthiocholine (ASCh) as substrate (1.25 mM), hydrolytic activities (A) of cholinesterase isoenzymes were determined after preincubation (60 min, 25 degrees C) of heart muscle samples with either saline (total activity, A tau), 7 microM mipafox (AM1), or 0.8 mM mipafox (AM2): (BChE) = A tau-AM1, (AChE) = AM1-AM2, (Atypical ChE) = AM2. 3. The mipafox differential inhibition assay was used to determine the substrate hydrolysis patterns of myocardial cholinesterases with ASCh, acetyl-beta-methylthiocholine (A beta MSCh), propionylthiocholine (PSCh), and butyrylthiocholine (BSCh). The substrate specificities of myocardial AChE and BChE resemble those of erythrocyte AChE and serum BChE, respectively. Michaelis constants KM with ASCh were determined to be 0.15 mM for AChE and 1.4 mM for BChE. 4. Atypical cholinesterase, in respect to both substrate specificity and inhibition kinetics, differs from cholinesterase activities of vertebrate tissue and, up to now, could be identified exclusively in heart muscle. The enzyme's Michaelis constant with ASCh was determined to be 4.0 mM. 5. The reversible inhibitory effects of physostigmine (eserine) and quinidine on heart muscle cholinesterases were investigated using the differential inhibition assay. With all three isoenzymes, the inhibition kinetics of both substances were strictly competitive. The physostigmine inhibition of AChE was most pronounced (Ki = 0.22 microM). Quinidine most potently inhibited myocardial BChE (Ki = 35 microM).

Vessel reconstruction in total coronary occlusions with a long subintimal wire pathway: use of multiple stents under guidance of intravascular ultrasound

A frequent cause of failure of the recanalization of a total coronary occlusion is a subintimal pathway of the guide wire. Three cases of occluded right coronary arteries are presented in which a distal reentry into the true vessel lumen was achieved. Intravascular ultrasound was used to locate the exit and reentry of the guide wire, and to plan the position of multiple stents for the coverage of this subintimal pathway. In all cases antegrade flow to the distal coronary bed was restored.

Cheyne-Stokes respiration and prognosis in congestive heart failure

Patients with congestive heart failure (CHF) frequently demonstrate Cheyne-Stokes respiration (CSR) with repetitive arousals and oxygen desaturations during sleep. Although it was evident from early publications that CSR during the daytime is a poor prognostic indicator in patients with CHF, it was speculated recently that CSR occurring during sleep could impede left ventricular function and even survival. We therefore followed up 36 patients with CHF and a left ventricular ejection fraction < or = 40% who underwent a sleep study at our institution. The patients showed a reduced ejection fraction (20 +/- 8%) and CSR with a median of 19% of total sleep time (lower and upper quartiles 9% and 56%). In 12 +/- 9% of their time in bed, the arterial oxygen saturation was <90%. No patient was lost to follow-up, which lasted for 32 +/- 15 months (range 11 to 53). One-year survival was 86 +/- 6%, and 2-year survival was 66 +/- 8%. Univariate comparisons for survival between groups stratified by the amount of CSR revealed no significant difference (log rank test, p = 0.84). However, the 20 patients with a left ventricular ejection fraction <20% had a shorter mean survival time than patients with an ejection fraction >20% (9.5 vs 28.3 months; log rank test, p = 0.013). Two patients with CSR during the daytime died within 1 month. No other patient had CSR during the daytime, and only 1 patient without daytime CSR died within 1 month (chi-square test, p <0.001). Higher age, reduced carbon dioxide end-tidal partial pressure, and increased transit time were found to be significantly related to the amount of nocturnal CSR. In conclusion, CSR occurring during sleep has no important prognostic impact in patients with CHF, but CSR present during the daytime suggests a high likelihood of dying within a few months.

Human corticotropin-releasing hormone and thyrotropin-releasing hormone modulate the hypercapnic ventilatory response in humans

Human corticotropin-releasing hormone (hCRH) and thyrotropin-releasing hormone (TRH) are known to stimulate ventilation after i.v. administration in humans. In a placebo-controlled, single-blind study we aimed to clarify if both peptides act by altering central chemosensitivity. Two subsequent CO2-rebreathing tests were performed in healthy young volunteers. During the first test 0.9% NaCl was given i.v.; during the second test 200 micrograms of hCRH (n = 12) or 400 micrograms of TRH (n = 6) was administered i.v. Nine subjects received 0.9% NaCl i.v. during both rebreathing manoeuvres. The CO2-response curves for the two tests were compared within the same subject. In the hCRH group a marked parallel shift of the CO2-response curve to the left was observed after hCRH (P < 0.01). The same effect occurred following TRH but was less striking (P = 0.05). hCRH and TRH caused a reduction in the CO2 threshold. The CO2-response curves in the control group were nearly identical. The results indicate an additive effect of both releasing hormones on the hypercapnic ventilatory response in humans, presumably independent of central chemosensitivity.

Indirect parasympathomimetic activity of the class III antiarrhythmic substance D/L-sotalol in vitro: reversible inhibition of cholinesterase isoenzymes from blood and the human central nervous system

Inhibitory effects of the class III antiarrhythmic compound D/L-sotalol on acetylcholinesterase (AChE; EC 3.1.1.7) isoenzymes of both erythrocytes and the human caudate nucleus and on serum cholinesterase (ChE; EC 3.1.1.8) were studied in vitro using a spectrophotometric kinetic assay with acetylthiocholine (ASCh) as substrate. Sotalol concentrations in the assays varied from 0.32 to 3.2 mM. All isoenzymes studied were inhibited by D/L-sotalol in a reversible and concentration-dependent manner. Double reciprocal plots of the reaction velocity against varying ASCh concentrations revealed that D/L-sotalol reduced substrate affinity (apparent Michaelis constant, KM, increased) of serum ChE, but did not change the enzyme's maximal rate of ASCh hydrolysis (Vmax). Thus, D/L-sotalol inhibition of serum ChE was of the competitive type (rate constant for reversible competitive inhibition: Ki = 0.51 mM). In contrast, D/L sotalol reduced the maximal reaction velocity of the AChE isoenzyme from the central nervous system (caudate nucleus), but had no influence on substrate affinity of the enzyme (KM with ASCh unchanged) indicating purely non-competitive inhibition kinetics (rate constant of reversible non-competitive inhibition: Ki = 0.44 mM). D/L-sotalol inhibition of erythrocyte AChE was of mixed competitive/non-competitive type (Ki = 0.31 mM, Ki = 0.49 mM). Non-competitive D/L-sotalol inhibition of caudate nucleus AChE and the non-competitive component of erythrocyte AChE inhibition cannot be overcome by increased concentrations of the cholinergic transmitter acetylcholine (ACh). Peak D/L-sotalol plasma levels as described in the literature for both humans (15 microM) and experimental animals (dogs: 18 microM; rats: 260 microM) as well as maximal myocardial concentrations of the substance (dogs: 46 microM; rats: 478 microM) are in the range of about 2% to 100% of the sotalol inhibition rate constants determined in the present paper for cholinesterase isoenzymes in vitro. Thus, D/L-sotalol inhibition of ACh hydrolysis in vivo may contribute to both the well known antiarrhythmic potential and proarrhythmic side effects of the compound.

Proliferative response of human and minipig smooth muscle cells after coronary angioplasty to growth factors and platelets

OBJECTIVES

Platelets aggregating at the site of angioplasty, shown to be a potent proliferative stimulus for cultured smooth muscle cells (SMC), could contribute to proliferation after angioplasty.

METHODS

SMC were cultivated from human aorta and restenosed coronary lesions as well as from minipig aorta and from normal and post angioplasty coronary artery segments (n = 6 per source). 3H-thymidine incorporation was used as a measure of proliferation.

RESULTS

3H-thymidine incorporation varied greatly after passage 7 in all cell lines, but was significantly higher in SMC from human coronary restenosed lesions compared to those from human aorta and minipig coronary post angioplasty segments in passage 2 (44 +/- 6.4 x 10(3) cpm/5000 SMC vs 20 +/- 3.9 and 12.1 +/- 2.1). However, all SMC exhibited a dramatic increase of 3H-incorporation after passage 7. Growth factors stimulated 3H-thymidine incorporation either dose dependently (PDGF-BB and bFGF) or only very modestly (PDGF-AA, EGF, IGF-1). The most potent stimulation was seen with PDGF-BB, 50 ng/ml, and was 17 +/- 6% (human restenosed) and 16 +/- 8% (minipig post angioplasty) of the values observed after stimulation with 10% fetal calf serum. The most effective combination of growth factors, PDGF-BB (50 ng/ml) + bFGF(20 ng/ml) + IGF-1 (50 ng/ml), produced a 3H-thymidine incorporation of 44 +/- 10% (human restenosed) and 42 +/- 11% (minipig post angioplasty) of FCS values. Stimulation by isolated platelets was dose dependent and significantly higher: 75 +/- 19% and 70 +/- 15% of FCS values for those SMC.

CONCLUSIONS

1) SMC from all sources studied exhibit significant changes of proliferation with increasing passages, excluding the comparability of data obtained with cells in different passages. 2) Data obtained with SMC from any source might not apply for SMC from human coronary restenosed lesions. 3) Currently tested growth factors do not fully account for the proliferative effect of platelets on cultured SMC.

Radiofrequency catheter ablation of right ventricular tachycardia late after repair of congenital heart defects

BACKGROUND

Ventricular arrhythmias after repair of congenital heart defects are a common finding and possibly contribute to sudden death in these patients. Optimal antiarrhythmic management has not yet been defined.

METHODS AND RESULTS

The study population consisted of 16 patients in whom ventricular arrhythmias occurred 11 to 42 years after complete surgical repair of congenital heart defects. Fifteen patients had a history of symptomatic sustained or nonsustained ventricular tachycardia, and 1 had frequent nonsustained ventricular tachycardia. The diagnostic mapping procedure to identify the origin of the arrhythmia included pace mapping during sinus rhythm, activation mapping, and pacing interventions during ventricular tachycardia. Catheter ablation was carried out by means of radiofrequency energy in the temperature-controlled mode. The follow-up period was 6 to 33 months (mean, 16 months). A right ventricular origin of the tachycardia in the surgically corrected area could be determined in all patients. Catheter ablation was carried out without complications. Immediate noninducibility was achieved in 15 of the 16 patients. One patient in whom the tachycardia was again inducible at repeat stimulation 1 week later was successfully treated with amiodarone. Eleven patients were taken off antiarrhythmic drugs. During follow-up, none of them had a recurrence of the tachycardia that had been ablated.

CONCLUSIONS

In patients with symptomatic or frequent ventricular tachycardia late after complete surgical repair of congenital heart defects, catheter ablation by means of radiofrequency energy is feasible and safe and thus might be taken into consideration for these patients. Short-term follow-up results are promising.

Assessment of myocardial viability in persistent defects on thallium-201 SPECT after reinjection using gradient-echo MRI

This prospective study assessed myocardial viability in 30 patients with coronary heart disease and persistent defects despite reinjection on TI-201 single-photon computed tomography (SPECT). In each patient, three observers graded TI-201 uptake in 7 left ventricular wall segments. Gradient-echo magnetic resonance imaging in the region of the persistent defect generated 12 to 16 short axis views representing a cardiac cycle. A total of 120 segments were analyzed. Mean end-diastolic wall thickness and systolic wall thickening (+/-SD) was 11.5 +/- 2.7 mm and 5.8 +/- 3.9 mm in 48 segments with normal TI-201 uptake, 10.1 +/- 3.4 mm and 3.7 +/- 3.1 mm in 31 with reversible lesions, 11.3 +/- 2.8 mm and 3.3 +/- 1.9 mm in 10 with mild persistent defects, 9.2 +/- 2.9 mm and 3.2 +/- 2.2 mm in 15 with moderate persistent defects, 5.8 +/- 1.7 mm and 1.3 +/- 1.4 mm in 16 with severe persistent defects, respectively. Significant differences in mean end-diastolic wall thickness (p < 0.0005) and systolic wall thickening (p < 0.005) were found only between segments with severe persistent defects and all other groups, but not among the other groups. On follow-up in 11 patients after revascularization, 6 segments with mild-to-moderate persistent defects showed improvement in mean systolic wall thickening that was not seen in 6 other segments with severe persistent defects. These data indicate that most myocardial segments with mild and moderate persistent TI-201 defects after reinjection still contain viable tissue. Segments with severe persistent defects, however, represent predominantly nonviable myocardium without contractile function.

DNA sequence recognition by hybridization to short oligomers: experimental verification of the method on the E. coli genome

A newly developed method for sequence recognition by hybridization to short oligomers is verified for the first time in genome-scale experiments. The experiments involved hybridization of 15,328 randomly selected 2-kb genomic clones of Escherichia coli with 997 short oligomer probes to detect complementary oligomers within the clones. Lists of oligomers detected within individual clones were compiled into a database. The database was then searched using known E. coli sequences as queries. The goal was to recognize the clones that are identical or similar to the query sequences. A total of 76 putative recognitions were tested in two separate but complementary recognition experiments. The results indicate high specificity of recognition. Current and prospective applications of this novel method are discussed.

Enhanced detection criteria in implantable cardioverter-defibrillators to avoid inappropriate therapy

The aim of this prospective study was to evaluate the efficacy and safety of enhanced detection criteria, stability and sudden onset, for ventricular tachycardia (VT) in the therapy of implantable cardioverter-defibrillators (ICDs). These detection enhancements ensure a high specificity in detecting VT, thereby avoiding inappropriate therapy delivery due to supraventricular tachycardia. However, delayed sensing or even undersensing of VT may lead to a problematic, even fatal, outcome. In our study, the stability detection enhancement was programmed to discriminate atrial fibrillation (AF) in 84 of 124 patients with implanted ICDs and the sudden-onset detection enhancement in 47 of the 124 patients to discriminate sinus tachycardia. Using these enhancements in 124 patients with third-generation ICDs, 13 patients (11%) had inappropriate therapy during 20 months of follow-up. AF caused shock delivery in 6 patients (5%) and antitachycardia pacing in 4 patients, atrial flutter triggered shock therapy in 1 patient, and sinus tachycardia caused shock delivery in 2 patients. In 3 of the 13 patients inappropriate therapy recurred despite reprogramming the detection enhancements. The stability parameter of 241 spontaneous VT episodes as measured by the devices was 8 +/- 7 msec. Only 10 (4%) VTs had a stability parameter >25 msec. In 46 patients a combination of both detection enhancements, stability and/or sudden onset, were programmed. The use of detection enhancements proved safe and no patient had suffered negative side effects due to prolonged detection time or therapy delay. Inappropriate shock delivery due to AF, a major complication in ICD therapy, was reduced to 5% of patients. The use of the stability enhancement is recommended for patients with intermittent or chronic AF. Selected patients profit from programming both the stability and sudden onset criteria.

Prevalence of obstructive sleep apnoea in patients with coronary artery disease

BACKGROUND

Obstructive sleep apnoea (OSA) is characterized by recurring upper airway collapse with continual respiratory effort during sleep, causing apnoea, a fall in arterial oxygen saturation, arousal and excessive daytime sleepiness. It is a common disorder, with an estimated prevalence of about 1-5% in the adult population. OSA is related to arterial hypertension, an essential risk factor for the development of coronary artery disease (CAD). Furthermore, a high dietary intake is a common risk factor for OSA as well as for CAD.

OBJECTIVE

To investigate the prevalence of OSA in CAD patients.

METHODS

A random sample of 50 patients (aged 61 +/- 6 years, body mass index 26.8 +/- 3.8 kg/m2) diagnosed to have CAD by coronary angiography was investigated prospectively. Respiration and nocturnal oxygen saturation were registered during one night. Snoring and daytime sleepiness were evaluated by a questionnaire.

RESULTS

In 25 patients the apnoea index was > 10/h sleep. Excessive daytime sleepiness was exhibited by eight of these patients. Nineteen of the patients with an apnoea index > 10/h participated in a full night polysomnography. The apnoea index was 17.0 +/- 10.9/h and the apnoea-hypopnoea index was 32.4 +/- 16.5/h sleep. The mean nadir oxygen saturation was 87.3 +/- 1.6% and the minimal oxygen saturation was 75.5 +/- 10.6%. For seven patients the apnoea index was > 20/h.

CONCLUSION

CAD patients have a high prevalence of OSA. Since obstructive apnoeas may trigger severe cardiac events such as myocardial ischaemia or ventricular tachycardias in CAD patients, the presence of OSA in these patients should be considered.