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Biomedical subjects

H Kelbaek

Publications and source records attributed to H Kelbaek.

At least 91 records · Page 5Linked to original sources
PubMed1987

First-pass radionuclide determination of cardiac output: an improved gamma camera method.

A technique for noninvasive determination of cardiac output by aid of first-pass radionuclide cardiography is described. After intravenous injection of 10-15 mCi technetium-99m-(99mTc) labeled red blood cells the method requires acquisition of a first passage time-activity curve recorded with a gamma camera over the left ventricle, the background corrected left ventricular count rate recorded after complete mixing of the tracer in the circulation, and determination of the distribution volume of the tracer. The method was applied in 14 patients with heart disease of various origins and evaluated against the conventional tracer dilution technique with arterial sampling of blood activity. Cardiac output determinations by external counting ranged from 2.30 to 8.56 l/min, mean +/- s.d. 4.50 +/- 1.66 l/min and by arterial blood sampling from 1.88 to 8.96 l/min, mean +/- s.d. 4.52 +/- 1.71 l/min. An excellent correlation was demonstrated between the two techniques, r = 0.978 (p less than 0.001). When no background subtraction was applied to the left ventricular counts at equilibrium, radionuclide cardiac output values were approximately 40% higher than those obtained by arterial sampling. The new first-pass radionuclide cardiographic technique may prove a useful tool in the noninvasive evaluation of cardiac function, especially in patients with arrhythmias and/or valvular incompetence.

Adult↗
PubMed1987

Determination of cardiac output by first passage radiocardiography: theoretical considerations and phantom studies.

Non-invasive determination of cardiac output by aid of precordial first passage radiocardiography may prove a useful tool in the management of cardiac disorders. The basic concepts of a method together with theoretical assumptions necessary for the clinical application of the method are described. The principle of the technique was tested in a cardiac phantom model with adjustable stroke volume and heart rate, in which background problems were avoided. First passage radiocardiography gave highly accurate cardiac output determinations compared with the 'true' phantom values, r = 0.998 (p less than 0.001).

Cardiac Output↗
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

Isolation and labelling of human leukocytes with 99mTc.

The role of the leukocyte isolation procedure on cell labelling with 99mTc has been evaluated. Separation of leukocytes was performed by two procedures: sedimentation on methyl cellulose, followed by discontinuous gradient centrifugation; methyl cellulose sedimentation and hypotonic haemolysis of residual red blood cells. After washing the cells in saline and incubation with a stannous pyrophosphate agent, the leukocytes were labelled with 5-10 mCi 99mTc. Procedure 1 gave a higher purity but lower recovery of polymorphonuclear leukocytes, and a minor contamination of red blood cells. 99mTc labelling of cells was slightly more efficient with this method, probably due to the presence of red blood cells. Procedure 1 is recommended for in vitro studies on cell kinetics and procedure 2 is recommended for clinical use.

Cell Separation↗
PubMed1986

Controlled double blind trial of nisoldipine in the treatment of idiopathic Raynaud's phenomenon.

In a controlled double blind trial the symptomatic effect of the calcium channel blocker nisoldipine was assessed in 19 patients with idiopathic Raynaud's phenomenon. Nisoldipine significantly reduced the frequency of attacks (p less than 0.05), whilst having a non-significant tendency (p less than 0.10) to reduce the severity of attacks. Side-effects were uncommon. It is concluded that nisoldipine is a promising agent for the symptomatic treatment of idiopathic Raynaud's phenomenon.

Adult↗
PubMed1986

Controlled double-blind trial of the clinical effect of nifedipine in the treatment of idiopathic Raynaud's phenomenon.

Twenty-six patients with idiopathic Raynaud's phenomenon participated in a double-blind, crossover clinical trial comparing the clinical effect of nifedipine with that of placebo. Four patients discontinued the study because of side effects and one patient defaulted at the return visit. Nifedipine significantly reduced frequency and severity of attacks (p less than 0.01). In an overall evaluation of drug effectiveness, 19 of 21 patients preferred nifedipine to placebo (p less than 0.01). Nifedipine proved to be effective in the treatment of idiopathic Raynaud's phenomenon, but side effects should be expected in some 30%.

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↗
PubMed1986

In vivo stability of in vitro labelled 99Tcm-red blood cells for radionuclide determination of left ventricular ejection fractions and volumes.

Serial determination of radionuclide left ventricular ejection fraction and volumes require a label that remains highly stable after introduction into the human circulation. We have evaluated the in vivo stability of 99Tcm-red blood cells (99Tcm-RBC) labelled in vitro by preparation with small amounts of a stannous agent in 19 patients with coronary artery disease. The distribution volume of 99Tcm-RBC was virtually identical to that of RBC labelled with 51Cr. Labelling efficiency expressed as the cell bound/total activity was more than 95% and remained high throughout 1 h after injection of the label. The effective in vivo half-times (T1/2) calculated from venous blood activity and externally recorded left ventricular end-diastolic frame activity were 342 +/- 103 min (mean +/- S.D.) and 306 +/- 92 min, respectively. A significant correlation, r = 0.86 (p less than 0.01) was found between the T1/2 values calculated from the two methods. Thus, a high in vivo stability of the label was demonstrated with considerable inter-patient variation. The labelling procedure seems suitable for serial performance of radionuclide cardiography within an hour after injection of 99Tcm-RBC. However, serial volume determination necessitates individual calculation of in vivo tracer decay from either venous blood or externally recorded activity in the left ventricular area during steady conditions.

Aged↗
PubMed1986

The influence of a background correction that considers the heart volume on radionuclide left ventricular ejection fraction determination.

A correction of background activity that considers the heart volume is introduced in radionuclide equilibrium cardiography. Left ventricular ejection fraction (LVEF) was determined in 19 patients with ischaemic heart disease by multigated equilibrium scan with 99Tcm-labelled red blood cells (99Tcm-RBC). Assuming that the majority of background activity in the ventricular and periventricular regions of interest arises from 99Tcm-RBC in lung tissue, a ventricular/periventricular background ratio was calculated from the distribution of 99Tcm-labelled macroaggregated albumin. The mean relative distribution of pulmonary 99Tcm-RBC activity in the ventricular region of interest was 0.590 (range 0.279-1.061) compared with the periventricular region. The modified background correction resulted in a mean LVEF of 43.0% (range 12.9-67.6%) compared with 46.8% (range 10.9-67.8%) with the standard correction, p less than 0.005. Since no attempt was made to calculate the proportion of 99Tcm-RBC activity arising from the myocardium and thoracic wall, this difference represents an upper limit of the general overestimation of LVEF obtained by the standard calculation. A further decrease in LVEF was seen when no background correction was applied. The present results suggest that standard LVEF calculation, by neglecting the background volume displaced by the cardiac blood pool, results in a slight overestimation of LVEF.

Background Radiation↗
PubMed1986

Technetium-99m labeling of red blood cells: in vitro evaluation of a new approach.

By titration of two different stannous kits for 99mTc labeling of red blood cells (RBC) we found concentrations of 1-2 micrograms tin per ml of blood to give the highest labeling yield. Using a new kit containing 2 micrograms of tin and 0.1% hypochlorite (NaOCl) as an oxidizing agent we labeled RBC with 99mTc avoiding centrifugation of cells. To evaluate this new procedure we assessed the dependency of tin incubation time, and addition of 4.4% EDTA as a chelating agent on labeling efficiency. We also measured the dependency of EDTA on the stability of the label. Optimal conditions for labeling of 1 ml of whole blood using the new stannous kit were: 5-10 min of tin incubation, 0.2 ml of 0.1% hypochlorite, and 15 min of 99mTc incubation. This procedure resulted in a labeling efficiency of at least 96%. The overall effect of EDTA was not an increased labeling efficiency, and EDTA increased the stability of the label with only a few percent. The promising results of this new labeling approach encourage to further laboratory investigations and eventual clinical evaluation of the procedure.

Erythrocytes↗
PubMed1985

[Cardiomyopathy].

Explore the source record for details and available documents.

Heart Diseases↗
PubMed1985

Effect of omeprazole and cimetidine on duodenal ulcer. A double-blind comparative trial.

We conducted a double-blind randomized study of 132 patients to determine whether the new, investigational proton-pump inhibitor, omeprazole (30 mg per day), would accelerate healing and pain relief, as compared with cimetidine (1 g per day), in patients with duodenal ulcer. After two weeks of treatment, which was completed by all patients, the healing rates were 73 per cent in the omeprazole group and 46 per cent in the cimetidine group (P less than 0.01). After four weeks of treatment, which was completed by 118 patients, the corresponding figures were 92 and 74 per cent (P less than 0.05). In the omeprazole group 55 per cent of the patients were free of pain after the first week, as compared with 40 per cent of those treated with cimetidine (P greater than 0.05). No major clinical or biochemical side effects of omeprazole or cimetidine were noted. A six-month follow-up study revealed no significant difference between the recurrence rates after omeprazole and after cimetidine treatment. In May 1984 clinical trials with omeprazole were temporarily suspended, since a study of long-term toxicity in rats had shown the development of gastric carcinoid tumors.

Adult↗
PubMed1985

Acute effects of alcohol on left ventricular function in healthy subjects at rest and during upright exercise.

Six healthy men, aged 23 to 30 years, were studied by radionuclide angiocardiography at rest and at 2 submaximal exercise levels in the upright position during increasing alcohol intoxication. At light intoxication (serum ethanol 23 mmol/liter), the median value of left ventricular (LV) ejection fraction (EF) at rest decreased by 5%. At heavy intoxication (serum ethanol 45 mmol/liter), the median LVEF decreased at rest by 11% and during 75% submaximal exercise by 6%, heart rate at rest increased (median 81 vs 62 beats/min), and systolic blood pressure decreased during 50% submaximal exercise (median 145 vs 163 mm Hg). No significant changes of plasma epinephrine concentrations were recorded, whereas plasma norepinephrine concentrations were increased by 24% at rest during light intoxication and by 30 to 38% during heavy intoxication. No changes of LVEF and plasma catecholamine levels were recorded after ingestion of isovolumic, isocaloric drinks as compared with values obtained before intake. Thus, influences of ingestion per se and repeated investigations of LV function were excluded. These findings suggest that in healthy subjects alcohol intoxication causes a dose-dependent impairment of cardiac contractility. Compensatory mechanisms may account for a reduced influence during exercise.

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

Controlled clinical trial of treatment with cimetidine for non-ulcer dyspepsia.

The effect of cimetidine (1 g daily) and placebo was studied in a controlled clinical trial comprising 50 patients with non-ulcer dyspepsia in whom an organic abnormality responsible for the dyspeptic symptoms was not disclosed by a standardized and extensive examination programme. Reduction of symptoms occurred in 13 (54%) out of 24 patients treated with cimetidine and in 16 (62%) out of 26 treated with placebo. The difference was insignificant, as were the alterations in the individual dyspeptic symptoms between the groups. Only 6 patients (25%) on cimetidine and 8 (31%) on placebo treatment had a total relief of symptoms. Of these, all cimetidine-treated patients remained free from symptoms during the successive 3-month observation period, while the dyspeptic symptoms relapsed in 3 (38%) placebo-treated patients. Subsequent resumption of placebo treatment reduced the symptoms in all 3 patients, but only one became free from symptoms. Cimetidine does not seem to be superior to placebo in the treatment of non-ulcer dyspepsia in patients without any previous history of ulcer or without any sign on endoscopy of an active or previous ulcer disease.

Adolescent↗