Comparative genomics of Lactobacillus sakei with emphasis on strains from meat.

Lactobacillus sakei is a lactic acid bacterium important in food microbiology mainly due to its ability to ferment and preserve meat. The genome sequence of L. sakei strain 23K has revealed specialized metabolic capacities that reflect the bacterium's adaption to meat products, and that differentiate it from other LAB. An extensive genomic diversity analysis was conducted to elucidate the core features of the species, and to provide a better comprehension of niche adaptation of the organism. Here, we describe the genomic comparison of 18 strains of L. sakei originating mainly from processed meat against the 23K strain by comparative genome hybridization. Pulsed field gel electrophoresis was used to estimate the genome sizes of the strains, which varied from 1.880 to 2.175 Mb, and the 23K genome was among the smallest. Consequently, a large part of the genome of this strain belongs to a common gene pool invariant in this species. The majority of genes important in adaption to meat products, the ability to flexibly use meat components, and robustness during meat processing and storage were conserved, such as genes involved in nucleoside scavenging, catabolism of arginine, and the ability to cope with changing redox and oxygen levels, which is indicative of the role these genes play in niche specialization within the L. sakei species. Moreover, an additional set of sequenced L. sakei genes beyond the 23K genome was present on the microarray used, and it was demonstrated that all the strains carry remnants of or complete bacteriocin operons. The genomic divergence corresponded mainly to five regions in the 23K genome, which showed features consistent with horizontal gene transfer. Carbohydrate-fermentation profiles of the strains were evaluated in light of the CGH data, and for most substrates, the genotypes were consistent with the phenotypes. We have demonstrated a highly conserved organization of the L. sakei genomes investigated, and the 23K strain is a suitable model organism to study core features of the L. sakei species.

Diversity of Lactobacillus sakei strains investigated by phenotypic and genotypic methods.

The diversity of 10 strains of Lactobacillus sakei, a commercially important species of lactobacilli, was characterized by studying food isolates. Growth characteristics varied among the strains when examined after growth in a complex medium and a defined medium with either glucose or ribose. A commercial starter culture strain showed the fastest growth rates and high biomass formation on all media, while two of the strains hardly grew on ribose. Based on acidification properties in a meat model, some of the strains had the ability to compete with the indigenous microbiota of the meat batter in addition to being fast acid producers. Carbohydrate-fermentation abilities revealed a relatively wide variation, clustering the strains into two phenotypic groups. The isolates were analyzed using different genetic fingerprinting techniques, demonstrating a distinction between two genetic groups, a grouping consistent with previous studies dealing with L. sakei strains. Comparative genome hybridization (CGH) was introduced for clustering the strains and the same division into two genetic groups was observed. Chromosomal sizes of the strains were estimated by pulsed field gel electrophoresis (PFGE) and were found to vary from 1884 to 2175 kb. The genetic groups did not correlate with the clustering obtained with carbohydrate-fermenting abilities or with chromosomal sizes.

Mixture models as a method to find present and divergent genes in comparative genomic hybridization studies on bacteria.

Comparative genomic hybridization (CGH) using microarrays is performed on bacteria in order to test for genomic diversity within various bacterial species. The microarrays used for CGH are based on the genome of a fully sequenced bacterium strain, denoted reference strain. Labelled DNA fragments from a sample strain of interest and from the reference strain are hybridized to the array. Based on the obtained ratio intensities and the total intensities of the signals, each gene is classified as either present (one copy or multiple copies) or divergent (zero copies). In this paper mixture models with different number of components are tted on different combinations of variables and compared with each other. The study shows that mixture models fitted on both the ratio intensities and the total intensities including the replicates for each gene improve, compared to previously published methods, the results for several of the data sets tested. Some summaries of the data sets are proposed as a guide for the choice of model and the choice of number of components. The models are applied on data from CGH experiments with the bacteria Staphylococcus aureus and

Survey of genomic diversity among Enterococcus faecalis strains by microarray-based comparative genomic hybridization.

We have compared nine Enterococcus faecalis strains with E. faecalis V583 by comparative genomic hybridization using microarrays (CGH). The strains used in this study (the "test" strains) originated from various environments. CGH is a powerful and promising tool for obtaining novel information on genome diversity in bacteria. By CGH, one obtains clues about which genes are present or divergent in the strains, compared to a reference strain (here, V583). The information obtained by CGH is important from both ecological and systematic points of view. CGH of E. faecalis showed considerable diversity in gene content: Compared to V583, the percentage of divergent genes in the test strains varied from 15% to 23%, and 154 genes were divergent in all strains. The main variation was found in regions corresponding to exogenously acquired or mobile DNA in V583. Antibiotic resistance genes, virulence factors, and integrated plasmid genes dominated among the divergent genes. The strains examined showed various contents of genes corresponding to the pTEF1, pTEF2, and pTEF3 genes in V583. The extensive transport and metabolic capabilities of V583 appeared similar in the test strains; CGH indicated that the ability to transport and metabolize various carbohydrates was similar in the test strains (verified by API 50 CH assays). The contents of genes related to stress tolerance appeared similar in V583 and the nine test strains, supporting the view of E. faecalis as an organism able to resist harsh conditions.

Hemodynamic and neurohumoral effects of continuous infusion of levosimendan in patients with congestive heart failure.

OBJECTIVES: We sought to define the therapeutic dose range of levosimendan in patients with New York Heart Association class II-IV heart failure of ischemic origin. BACKGROUND: Levosimendan is a calcium sensitizer for treatment of acute decompensated heart failure. METHODS: A double-blind, placebo-controlled, randomized, multicenter, parallel-group study included 151 adult patients. Levosimendan was given as a 10-min intravenous bolus of 3, 6, 12, 24 or 36 microg/kg, followed by a 24-h infusion of 0.05, 0.1, 0.2, 0.4 or 0.6 microg/kg/min, respectively. Dobutamine, for comparative purposes, was given as an open-label infusion (6 microg/kg/min). The primary efficacy variable was the proportion of patients achieving in each treatment group at least one of the following: 1) a > or =15% increase in stroke volume (SV) at 23 h to 24 h; 2) a > or =25% decrease in pulmonary capillary wedge pressure (PCWP) (and > or =4 mm Hg) at 23 h to 24 h; 3) a > or =40% increase in cardiac output (CO) (with change in heart rate [HR] <20%); 4) a > or =50% decrease in PCWP during two consecutive measurements. RESULTS: The response rate to levosimendan ranged from 50% at the lowest dose to 88% at the highest dose (compared with placebo 14%, dobutamine 70%). A dose-response relationship was demonstrated for levosimendan on increases in CO and SV, and reductions in PCWP during the infusion (for all, p< or =0.001). Headache (9%), nausea (5%) and hypotension (5%) were the most frequently reported adverse events at higher dosages. CONCLUSIONS: Dosing of levosimendan with a 10-min bolus of 6 to 24 microg/kg followed by an infusion of 0.05 to 0.2 microg/kg/min is well tolerated and leads to favorable hemodynamic effects.

The value of repeated echocardiographic evaluation in patients with idiopathic dilated cardiomyopathy during treatment with metoprolol or captopril.

Serial echocardiographic investigations were carried out on patients with idiopathic dilated cardiomyopathy, to evaluate treatment effects on left ventricular (LV) performance during therapy with either metoprolol or captopril. Thirty-two patients (23 males and 9 females) with mild to moderate symptoms of heart failure (NYHA II-III) and a mean age of 49 years were included in the investigation. The patients were investigated with Doppler echocardiography before treatment, after 3 and 6 months of treatment (either metoprolol or captopril) and 1 month after withdrawal of treatment. Intra- and inter-investigator reproducibility was acceptable, with a coefficient of variation of less than 5% for LV dimensions. A reduction in LV dimensions was seen in both treatment groups. In the metoprolol group there was also an increase in LV stroke volume and fractional shortening. The non-invasive data were in accordance with invasive measurements of stroke volume and LV filling pressure. In patients with idiopathic dilated cardiomyopathy and mild to moderate symptoms of heart failure, echocardiography seemed to be sufficiently reproducible to be used for determination of treatment effects in a longitudinal heart failure study. Both metoprolol and captopril were well tolerated and had favourable effects on LV performance.

The effects of metoprolol and captopril on heart rate variability in patients with idiopathic dilated cardiomyopathy.

BACKGROUND: The effects of treatment with captopril or metoprolol on heart rate variability (HRV) were investigated in 38 patients (29 men and 9 women) with mild to moderate symptoms of heart failure due to idiopathic dilated cardiomyopathy (DCM). HYPOTHESIS: The aim of the study was to investigate and compare the effects of the angiotensin-converting enzyme inhibitor captopril with those of the selective beta-adrenergic receptor blocker metoprolol on HRV in patients with idiopathic DCM. METHODS: Heart rate variability was analyzed in the time and frequency domains from 18th of Holter monitoring before randomized treatment was started, after 6 months of therapy, and 1 month after therapy was stopped. RESULTS: Captopril treatment increased HRV expressed as total power and low-frequency power in the frequency domain. There was no change in the time domain. In the metoprolol group, there was a pronounced increase in both time- and frequency-domain indices of HRV. The increase in total power was partly maintained 1 month after therapy was stopped in both treatment groups. CONCLUSION: Treatment with captopril and metoprolol increases HRV in patients with DCM. This effect seems to be maintained for at least 1 month after therapy is stopped. The increase in HRV seems to be more pronounced with metoprolol, and the two different pharmacologic approaches may have additive effects that are of prognostic importance in patients with heart failure.

The circulating renin-angiotensin system during treatment with metoprolol or captopril in patients with heart failure due to non-ischaemic dilated cardiomyopathy.

OBJECTIVE: To investigate the effects of beta-blocker (metoprolol) or angiotensin-converting enzyme inhibitor (captopril) treatment on neurohormonal function in a randomized prospective study on patients with heart failure due to dilated cardiomyopathy. PATIENTS: Fifty-four patients (42 men and 12 women, mean age 50 years) were studied. There were three patients in NYHA (New York Heart Association) functional class I, 32 patients in class II and 19 patients in class III. METHODS: Measurements of plasma renin activity (PRA). plasma angiotensin II (A II) concentration and plasma atrial natriuretic peptide (ANP) concentration were made at rest and also in a subgroup (n = 32) during exercise. The urinary excretion of aldosterone was also determined. Investigations were performed at baseline, and after 3 and 6 months. Therapy was then stopped and the patients were re-investigated 1 month thereafter. RESULTS: The mean level of PRA was normal at baseline, reduced during therapy with metoprolol, and increased during therapy with captopril. The mean plasma concentration of A II was reduced during exercise and there was a trend towards a reduction even at rest in the metoprolol group, but not in the captopril group. The urinary excretion of aldosterone decreased in both groups. The mean plasma concentration of ANP was elevated at baseline and declined during exercise in the metoprolol group. CONCLUSION: In patients with dilated cardiomyopathy and only a partly activated renin-angiotensin system, both metoprolol and captopril reduced urinary excretion of aldosterone. Furthermore, metoprolol suppressed the exercise-induced increase in ANP, suggesting a favourable effect on ventricular performance.

The prevalence of chronic Chlamydia pneumoniae infection as detected by polymerase chain reaction in pharyngeal samples from patients with ischaemic heart disease.

AIMS: Cross-sectional serological studies have suggested an association between ischaemic heart disease and infections from Chlamydia pneumoniae and Helicobacter pylori. We therefore sought to find out if patients with ischaemic heart disease had an increased prevalence of C. pneumoniae in the pharynx. As the course of the C. pneumoniae infection remains unclear, both acute and follow-up samples were taken and compared with antibody levels. METHODS AND RESULTS: We studied 282 patients with ischaemic heart disease. One hundred and two subjects without history or symptoms of ischaemic heart disease served as controls. Pharyngeal specimens for polymerase chain reaction detection of C. pneumoniae, and blood samples for C. pneumoniae and H. pylori antibody detection, were collected. In patients with positive polymerase chain reaction or C. pneumoniae IgA titres > or = 32, indicating current infection, convalescent samples were taken at least 6 weeks later. An immunofluorescent antigen detection test was used to confirm the presence of C. pneumoniae elementary bodies in specimens found to be polymerase chain reaction positive. The prevalence of positive polymerase chain reaction tests was 36% among patients and 22% among controls (P<0.05). Forty-seven percent of patients with positive polymerase chain reaction remained positive in the convalescent test. Elevated C. pneumoniae IgG titres > or = 512 were found in 39% of patients and 26% of the controls (P<0.05). IgA titres > or = 32 were found in 46% of the patients and 44% of the controls (ns). Antibody titres remained largely unchanged at convalescent testing. Two patients and none of the controls had IgM titres > 16. There was no link between positive H. pylori serology and positive C. pneumoniae polymerase chain reaction tests. CONCLUSIONS: The high prevalence and persistence of positive pharyngeal C. pneumoniae polymerase chain reaction and elevated antibody titres in patients with ischaemic heart disease indicate a chronic infection. The pharyngeal presence of C. pneumoniae might contribute to a low grade inflammatory activation or be a source for further spread of the bacteria to atherosclerotic vessels.

Excellent reliability of nurse-based bedside diagnosis of acute myocardial infarction by rapid dry-strip creatine kinase MB, myoglobin, and troponin T.

With the aim to compare the diagnostic efficacy as regards acute myocardial infarction of two rapid dry-strip tests, one with both creatine kinase MB (CK-MB) and myoglobin (C + M) and the other with troponin T, and to test the reliability of bedside diagnosis by the coronary care unit (CCU) nurse, 151 patients with acute chest pain admitted to the CCU were investigated. There was no difference in diagnostic performance between rapid tests and quantitative determinations. With <6-hour duration of symptoms, the sensitivity was better for C + M than for troponin T (72% vs 33%, p < 0.05). With symptoms lasting >12 hours on arrival, troponin T performed better, with 100% sensitivity and a negative predictive value of 100% in the 6-hour retest. For exclusion of damage, the two tests have similar and reliable diagnostic capacities 12 hours after the onset of symptoms. The bedside diagnosis or exclusion of acute myocardial infarction was carried out rapidly (within 20 minutes) and reliably by the CCU nurses.

Intravenous nitroglycerin reduces ischaemia in unstable angina pectoris: a double-blind placebo-controlled study.

OBJECTIVE: To study whether intravenous nitroglycerin (NTG) reduces the incidence of ischaemic events and leucocyte activation, as well as inhibiting platelet aggregation in patients with unstable angina pectoris. DESIGN: Randomized double-blind placebo-controlled study. SUBJECTS: One hundred and sixty-two patients with a history and electrocardiographic changes suggesting unstable angina pectoris. INTERVENTIONS: A 48-hour titrated intravenous infusion of NTG or placebo. RESULTS: Of the 162 randomized patients, 19 were excluded because of an acute myocardial infarction on randomization (11 patients) or proven presence of a non-ischaemic cause of the pain (6 patients). Other causes (2 patients). No differences in the clinical findings were detected between the groups on randomization. In the comparison of NTG and placebo, fewer patients in the former group had more than two new attacks of chest pain lasting for < 20 min or one new attack of chest pain lasting > 20 min, despite sublingual NTG (13/25, P < 0.03). In addition, the attacks of pain lasting > 20 min in the NTG group were delayed compared to those in the placebo group (P < 0.05), suggesting a beneficial effect on these more severe episodes. Fewer patients in the NTG group required more than two sublingual NTG tablets (P < 0.005). NTG also reduced the rate-pressure product (P < 0.05), compared to placebo after 2 h but not after 24 h. Compared to baseline, platelet aggregation was inhibited in the patients who had received an NTG infusion for 2 h (P < 0.05). In both groups, leucocytes were activated at baseline, but remained unchanged thereafter. CONCLUSIONS: Intravenous NTG seems to reduce myocardial ischaemia in patients with unstable angina pectoris more than the placebo.

More favourable haemodynamic effects from metoprolol than from captopril in patients with dilated cardiomyopathy.

AIM: The object of this study was to investigate and compare the haemodynamic effects of treatment with a beta receptor blocker (metoprolol) or an angiotensin-converting-enzyme inhibitor (captopril) in 54 patients with idiopathic dilated cardiomyopathy. METHOD: All patients had cardiac catheterization performed at rest and during exercise, before and after 3 months of treatment. RESULTS: The mean dose of metoprolol was 135 mg.day-1 and of captopril 98 mg.day-1. After treatment there was a significant reduction in left ventricular filling pressure both at rest (from 16 to 12 mmHg) and during exercise (from 27 to 20 mmHg) in the metoprolol group. In the captopril group a significant reduction was seen only during exercise (25 to 20 mmHg), compared to baseline. The stroke volume increased significantly after 3 months of therapy in the metoprolol group, both at rest (53 to 70 ml) and during exercise (56 to 79 ml). In the captopril group the increase reached significance only during exercise (72 to 79 ml). Cardiac output was maintained in both groups. CONCLUSION: There were positive effects on left ventricular function in the metoprolol group as well as in the captopril group. Metoprolol reduced left ventricular filling pressure at rest and increased stroke volume both at rest and during exercise significantly more than captopril.

No difference in blood thiamine diphosphate levels between Swedish Caucasian patients with congestive heart failure treated with furosemide and patients without heart failure.

OBJECTIVES: To determine whether furosemide treatment in congestive heart failure (CHF) patients is associated with thiamine deficiency. DESIGN: Patients without heart failure and without diuretic treatment were included to compare with patients with CHF belonging to New York Heart Association (NYHA) functional class II and III-IV, respectively, and receiving furosemide therapy. SETTING: All patients were recruited from the emergency ward of the cardiology section. Huddinge University Hospital, where they were admitted due to CHF or acute myocardial infarction. SUBJECTS: Ninety-nine patients were included from whom a blood sample was taken, as well as routine admission blood samples for the analysis of thiamine diphosphate (TPP) concentrations. Patients taking vitamin preparations were excluded. MAIN OUTCOME MEASURES: Blood TPP concentrations were measured by high performance liquid chromatography (HPLC) and compared between the patient groups by the use of ANOVA. RESULTS: No significant difference was found between the groups in blood TPP concentrations. CONCLUSIONS: Thiamine deficiency may not be a complication of furosemide treatment in the studied Swedish patient population.

[What do we know today about neuroleptic malignant syndrome?]. / Hva vet vi i dag om malignt neuroleptikasyndrom?

Neuroleptic malignant syndrome is a complication that may occur during treatment with neuroleptic drugs, or after abrupt cessation of dopaminagonists. Although the condition is relatively rare, it has a high mortality of about 20% when untreated. The first symptoms can appear the first day after initiation of treatment with neuroleptic drugs. The syndrome manifests itself in the form of a tetralogy composed of extrapyramidal symptoms, a change in the level of conciousness, elevated body temperature and autonomic instability. It is also associated with secondary laboratory findings such as increased creatine kinase and leucocyte count. Treatment includes stopping the neuroleptic drugs, application of dopaminagonists, benzodiazepines and fluid replacement. If the patient, after an episode of neuroleptic malignant syndrome, has a psychotic relapse, neuroleptica can be recommended after a break of one to four weeks. Two cases are described to demonstrate the picture.

Beat-to-beat QRS amplitude variability during dobutamine infusion in patients with coronary artery disease.

The aim of this study was to investigate if provoked myocardial ischemia induces increased beat-to-beat QRS amplitude variability in patients with angiographically verified coronary artery disease. 15 patients (median age 62 years, range 46-73 years) and 10 healthy controls (median age 25 years, range 22-42 years) were studied. Dobutamine was infused intravenously at a low and at a high dose. The mean low dose of the drug was 10.0 micrograms/kg/min for both patients and controls, whereas the mean maximum dose was 31 +/- 2 for patients and 38 +/- 1 microgram/kg/min for controls. The total QRS amplitude beat-to-beat variance from 12 leads as well as individual variance scores in each single lead were evaluated. Before infusion, the total QRS variance did not differ between patients and controls, nor did the individual variance in 9 of the 12 ECG leads. Dobutamine elicited an increase (p < 0.01) in the total QRS variance, with significantly higher (p < 0.001) total variance in patients than in controls. At the high dose of the drug, the patients displayed significantly higher individual variance values in each ECG lead as well. During dobutamine infusion, 7 of 15 patients developed ST depressions (> or = 0.1 mV in > or = 2 leads) in 12-lead ECG readings. Eleven of 15 patients developed chest pain (grade > or = 3 at the Borg's CR-10 scale). In conclusion, in patients with ischemic heart disease, dobutamine-provoked stress gives rise to increased QRS amplitude beat-to-beat variability, as a sign of electrical instability of the myocardium.

Creatine supplementation in chronic heart failure increases skeletal muscle creatine phosphate and muscle performance.

BACKGROUND: Cardiac creatine levels are depressed in chronic heart failure. Oral supplementation of creatine to healthy volunteers has been shown to increase physical performance. AIM: To evaluate the effects of creatine supplementation on ejection fraction, symptom-limited physical endurance and skeletal muscle strength in patients with chronic heart failure. METHODS: With a double-blind, placebo-controlled design 17 patients (age 43-70 years, ejection fraction < 40) were supplemented with creatine 20 g daily for 10 days. Before and on the last day of supplementation ejection fraction was determined by radionuclide angiography as was symptom-limited 1-legged knee extensor and 2-legged exercise performance on the cycle ergometer. Muscle strength as unilateral concentric knee extensor performance (peak torque, Nm at 180 degrees/s) was also evaluated. Skeletal muscle biopsies were taken for the determination of energy-rich phosphagens. RESULTS: Ejection fraction at rest and at work did not change. Performance before creatine supplementation did not differ between placebo and creatine groups. While no change was seen in the placebo group compared to baseline, creatine supplementation increased skeletal muscle total creatine and creatine phosphate by 17 +/- 4% (P < 0.05) and 12 +/- 4% (P < 0.05), respectively. Increments were seen only in patients with < 140 mmol total creatine/kg d.w. (P < 0.05). One-legged performance (21%, P < 0.05), 2-legged performance (10%, P < 0.05), and peak torque, Nm (5%, P < 0.05) increased. Both peak torque and 1-legged performance increased linearly with increased skeletal muscle phosphocreatine (P < 0.05). The increments in 1-legged, 2-legged and peak torque were significant compared to the placebo group, (P < 0.05). CONCLUSIONS: One week of creatine supplementation to patients with chronic heart failure did not increase ejection fraction but increased skeletal muscle energy-rich phosphagens and performance as regards both strength and endurance. This new therapeutic approach merits further attention.

Influence of angiotensin converting enzyme inhibition on relation of atrial natriuretic peptide concentration to atrial pressure in heart failure.

OBJECTIVE: To examine the relation between haemodynamics and atrial natriuretic peptide concentration during short term angiotensin converting enzyme inhibition. DESIGN: Patients were randomly allocated to receive placebo or one of three doses of the angiotensin converting enzyme inhibitor ramipril. SETTING: Cardiac units of two tertiary referral hospitals. SUBJECTS: 38 Patients with stable congestive heart failure caused by ischaemic heart disease. METHODS: Data were collected over a 24 hour period and assessed with the aim of distinguishing between the haemodynamic effects on plasma concentrations of atrial natriuretic peptide and the direct effects of the study drug, vasopressin concentrations, and angiotensin converting enzyme activity. RESULTS: Pulmonary capillary wedge pressure was the main predictor of the plasma concentration of atrial natriuretic peptide. A higher plasma concentration of this peptide with a given pulmonary capillary wedge pressure was found after 24 hours of treatment with 2.5 mg and 5 mg of ramipril. Plasma concentration of the active metabolite, change in arginine vasopressin concentration or degree of angiotensin converting enzyme inhibition did not significantly predict change in plasma concentration of atrial natriuretic peptide or in the ratio of atrial natriuretic peptide concentration to pulmonary capillary wedge pressure. CONCLUSIONS: A gradual increase in plasma concentration of atrial natriuretic peptide with a given pulmonary capillary wedge pressure, occurs during short term high degree inhibition of angiotensin converting enzyme. The causative mechanisms are yet to be identified. Such a change in the relation between central haemodynamics and atrial natriuretic peptide concentration may contribute to the beneficial effects of angiotensin converting enzyme inhibition in patients with congestive heart failure due to ischaemic heart disease.

Short-term effects of eating on vasoactive hormones and haemodynamics in patients with heart failure.

OBJECTIVES: To investigate if eating can influence the measurements of vasoactive hormones or their relationship to important haemodynamic variables. DESIGN: Haemodynamic variables and plasma concentrations of atrial natriuretic peptide (ANP), arginine vasopressin and angiotensin enzyme (ACE) activity were measured. During the 24-h study period the patients ate ordinary hospital meals and thus were studied both in the absorptive and post-absorptive phases. SETTING: Two university hospitals in Sweden participated in the study. SUBJECTS: Ten patients with heart failure, due to ischaemic heart disease. INTERVENTION: Eating. MAIN OUTCOME MEASURES: Change in haemodynamic variables and plasma concentrations of vasoactive hormones related to eating. RESULTS: After a meal (absorptive phase) pulmonary capillary wedge pressure and plasma concentrations of ANP were significantly lower compared to the postabsorptive phase, 13 +/- 1.7 vs. 16 +/- 1.9 mmHg and 57 +/- 9.5 vs. 72 +/- 12.2 pmol l-1, respectively. The relationship between ANP and its main predictor, pulmonary capillary wedge pressure, was not altered during the study period. Plasma concentration of arginine vasopressin, ACE activity and mean right atrial pressure decreased with time and the cardiac index increased with time over the study period. CONCLUSIONS: A meal may significantly influence plasma concentrations of ANP. Studies on vasodilator treatment and its interactions with ANP should take account of these basal fluctuations. The present data confirm previous reports on haemodynamic improvement during the first 24 h of supine cardiac catheterization in patients with heart failure, and add new information about decreasing concentrations of arginine vasopressin and ACE.

Variance ECG detection of coronary artery disease--a comparison with exercise stress test and myocardial scintigraphy.

Variance electrocardiogram (ECG) is a newly developed method by which resting ECG is registered with 24 leads during 220 beats. The temporal beat-to-beat QRS microamplitude variability is computed and a nondimensional diagnostic variance ECG coronary artery disease (CAD) index is derived from it. Consecutive outpatients (n = 160) were referred to myocardial scintigraphy (SPECT) investigation for the evaluation of angina pectoris. The variance ECG CAD index was compared with a symptom-limited exercise stress test and SPECT during and after the exercise test and with coronary angiography (n = 67). Discriminant accuracy was tested with receiver-operating characteristics (ROC). Relative to angiographic coronary pathology (prevalence 0.85), diagnostic information for the variance ECG CAD index and for SPECT were both p < 0.001, while the outcome of the exercise stress test was non-contributory. Prevalence of persistent or transient perfusion defects at SPECT was 0.59. The exercise stress test had a diagnostic capacity of p < 0.01 for transient perfusion defects and variance ECG CAD index showed a high diagnostic performance (p < 0.001) for persistent perfusion defects. Overall pathology at SPECT was better (p < 0.05) identified by variance ECG CAD index than by symptom-limited exercise stress test. It was concluded that in this high prevalence population the variance ECG CAD index has a diagnostic capacity at least as good as that of SPECT and better than that of the exercise stress test. The variance ECG CAD index was strongly diagnostic for persistent perfusion defects while exercise stress test was slightly diagnostic for transient perfusion defects. Therefore, the two tests provide complementary diagnostic information.