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Biomedical subjects

B Vestergaard

Publications and source records attributed to B Vestergaard.

9 recordsLinked to original sources
PubMed2001

Bacterial polypeptide release factor RF2 is structurally distinct from eukaryotic eRF1.

Bacterial release factor RF2 promotes termination of protein synthesis, specifically recognizing stop codons UAA or UGA. The crystal structure of Escherichia coli RF2 has been determined to a resolution of 1.8 A. RF2 is structurally distinct from its eukaryotic counterpart eRF1. The tripeptide SPF motif, thought to confer RF2 stop codon specificity, and the universally conserved GGQ motif, proposed to be involved with the peptidyl transferase center, are exposed in loops only 23 A apart, and the structure suggests that stop signal recognition is more complex than generally believed.

Amino Acid Sequence↗
PubMed1989

The value of the left ventricular ejection fraction in the treatment of angina pectoris following acute myocardial infarction: a randomized double blind study.

Radionuclide determination of left ventricular ejection fraction was performed at hospital discharge and one month later in 60 patients who had suffered acute myocardial infarction. At the first determination, the patients were randomized into two groups. In the first group, the cardiologist who cared for the patients was provided with the result of the determination of the ejection fraction whereas, in the second group, the result was withheld. At a 'blinded' evaluation two months after hospital discharge, 7 of those patients (24%) from the group where the cardiologist knew the ejection fraction and 11 of the patients (38%) in whom this result was withheld complained of angina pectoris on exertion (ns). The medication of the patients did not differ in the two groups. No significant difference was found in the values of the ejection fraction in patients with and without angina pectoris. In this controlled study, we were not able to document a clinical effect by routinely determinating left ventricular ejection fraction in patients with acute myocardial infarction in the treatment of angina pectoris.

Adrenergic beta-Antagonists↗
PubMed1989

Reproducibility in the analysis of multigated radionuclide studies of left ventricular ejection fraction.

The authors determined the reproducibility (the standard deviation [SD]) in the analysis of multigated radionuclide studies of left ventricular ejection fraction (LVEF). Radionuclide studies from a consecutive series of 38 patients suspected of ischemic heart disease were analyzed independently by four nuclear medicine physiologists and four laboratory technicians. Each study was analyzed three times by each of the observers. Based on the analyses of the eight observers, the SD could be estimated by the use of a variance component model for LVEF determinations calculated as the average of the analyses of an arbitrary number of observers making an arbitrary number of analyses. This study presents the SDs for LVEF determinations based on the analyses of one to five observers making one to five analyses each. The SD of a LVEF determination decreased from 3.96% to 2.98% when an observer increased his number of analyses from one to five. A more pronounced decrease in the SD from 3.96% to 1.77% was obtained when the LVEF determinations were based on the average of a single analysis made by one to five observers. However, when dealing with the difference between LVEF determinations from two studies, the highest reproducibility was obtained if the LVEF determinations at both studies were based on the analyses made by the same observer. No significant difference was found in the reproducibility of analyses made by nuclear medicine physicians and laboratory technicians. Our study revealed that to increase the reproducibility of LVEF determinations, special efforts should be made to standardize the outlining of the end-systolic region interest.

Adult↗
PubMed1989

Screening of kidney function by plasma creatinine and single-sample 51Cr-EDTA clearance determination--a comparison.

Nomograms or simple formulas have been suggested for estimating the glomerular filtration rate (GFR) from either plasma creatinine (ClK) or from a single plasma sample drawn after an intravenous injection of 51Cr-EDTA (ClA/B). This study compares the precision of estimating GFR as ClK and ClA/B. A multiple plasma-sample standard method (ClSM) served as reference. The comparison was performed in 136 individuals. The variance of ClA/B on ClSM was 14.4 ml/min/1.73 m2 while the variance of ClK on ClSM was 204.5 ml/min/1.73 m2. It is concluded that the ClA/B values are more precise than the ClK values (p less than 0.01). The single-sample method for determination of 51Cr-EDTA clearance seems well-suited for evaluation and monitoring of patients with known or suspected kidney diseases. It may even be applied for screening purposes in cases where plasma creatinine would otherwise have been chosen instead of the usual resource-demanding method for determination of ClSM.

Chromium Radioisotopes↗
PubMed1986

Prospective, randomised, double-blind study of radionuclide determination of left-ventricular ejection fraction in acute myocardial infarction.

In a controlled, randomised, double-blind study to see whether knowledge of left-ventricular ejection fraction (LVEF) could reduce the frequency of left-sided heart failure after acute myocardial infarction, LVEF was determined a few days before hospital discharge in a consecutive series of 60 patients. Subsequently, the patients were randomly assigned to two groups. The cardiologist responsible for their treatment was aware of the LVEF result in group I but not in group II. A month after hospital discharge there was no significant difference in the LVEF between the groups. 2 months after discharge there were no significant differences between the groups in clinical and radiological signs of left-ventricular heart failure or the use of drugs. The cardiologist's clinical estimate of the LVEF and the result of the radionuclide determination were significantly correlated. Thus, the use of LVEF did not change the clinical outcome. The need for randomised controlled studies in the evaluation of diagnostic methods is emphasised.

Adult↗
PubMed1986

Cardiac function and plasma catecholamines during upright exercise in healthy young subjects.

Radionuclide left ventricular ejection fraction, left ventricular volume changes and plasma catecholamines were recorded in six healthy untrained male subjects at rest and during upright exercise at increasing work loads. During mild submaximal exercise mean left ventricular ejection fraction increased 10% because of end-diastolic dilation, while a further 4% increase of left ventricular ejection fraction was recorded at heavy submaximal exercise mainly due to increased end-systolic contraction. Great individual changes were recorded during maximal exercise. Alterations in plasma catecholamines were most pronounced at the high exercise levels indicating that changes in cardiac contractility are not linearly correlated with changes in sympathetic nervous activity. Repeat studies showed only minor variations of mean left ventricular ejection fraction and plasma catecholamines indicating an acceptable reproducibility of the measurements. Variations of both left ventricular ejection fraction and catecholamines were smaller during exercise than at rest.

Adult↗
PubMed1985

Scintigraphic demonstration of subcutaneous abscesses with 99mTc-labeled leukocytes.

Our initial experience with the clinical application of autologous leukocytes labeled in vitro with technetium 99m is reported. An injection of 3.6 X 10(8) leukocytes (83% of which were polymorphonuclear) labeled with 6.4 mCi 99mTc was administered to a patient with subcutaneous abscesses in order to evaluate the in vivo stability of the labeling and cellular function. Scintigraphic examinations demonstrated marked accumulations of radioactivity at the sites of inflammation, suggesting that 99mTc was efficiently bound to the cells and that the migration of polymorphonuclear leukocytes was not disturbed by the labeling procedure.

Abscess↗
PubMed1985

Right ventricular ejection fraction determined in three projections.

The right ventricular ejection fraction (RVEF) was successively determined in three projections in ten healthy volunteers aged 28-53, mean 37 years, with a first-pass technique using 99Tcm-labelled red blood cells and a gamma camera coupled to a computer. In the anterior-posterior projection (AP) the mean RVEF was 39.3%, range 26-49%, in the left anterior oblique (LAO) 43.7% (36-58), and in the right anterior oblique (RAO) 44.5% (36-54). These mean values do not differ significantly (P = 10%). The results from one of the subjects were withdrawn, as they deviated markedly from the general pattern, and the data were reanalysed from the remaining 9 subjects. Now the mean RVEF in the AP projection was 38.2%, which is significantly lower (P = 1%) than the corresponding RVEF of 44.3% in the LAO projection and of 45.2% in the RAO projection. Our results suggest that when using the classic first-pass technique, the right ventricle histograms will in any projection be influenced by the activity in the right atrium and the large vessels.

Adult↗