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Biomedical subjects

S Holmberg

Publications and source records attributed to S Holmberg.

At least 199 records · Page 11Linked to original sources

Effect on mortality of metoprolol in acute myocardial infarction. A double-blind randomised trial.

The effect of metoprolol on mortality was compared with that of placebo in a double blind randomised trial in patients with definite or suspected acute myocardial infarction. Treatment with metoprolol or placebo started as soon as possible after the patient's arrival in hospital and was continued for 90 days. Metoprolol was given as a 15 mg intravenous dose followed by oral administration of 100 mg twice daily. 1395 patients (697 on placebo and 698 on metoprolol) were included in the trial. Definite acute myocardial infarction developed in 809 and probable infarction in 162. Patients were allocated to various risk groups and within each group patients were randomly assigned to treatment with metoprolol or placebo. There were 62 deaths in the placebo group (8.9%) and 40 deaths in the metoprolol group (5.7%), a reduction of 36% (p less than 0.03). Mortality rates are given according to the treatment group to which the patients were initially randomly allocated.

Adult↗

Ductus arteriosus closure may result from suppression of prostacyclin synthetase by an intrinsic hydroperoxy fatty acid.

Fetal sheep ductus arteriosus readily synthesizes prostacyclin from exogenous prostaglandin endoperoxides, and in the presence of high oxygen tension, this synthesis is markedly suppressed. Fetal aorta and pulmonary artery also synthesize prostacyclin; however, this synthesis is much less suppressed by high oxygen tension. We propose that ductal closure may be regulated by the oxygen dependent synthesis of hydroperoxy fatty acid which would block the production of the vasodilatory prostacyclin and expose the direct contractile properties of intrinsic prostaglandin endoperoxide. This mechanism would result in ductal closure at birth.

6-Ketoprostaglandin F1 alpha↗

Role of a serum factor in enhancement of in vitro interactions between Plasmodium berghei sporozoites and hamster peritoneal macrophages.

Interactions between Plasmodium berghei sporozoites and hamster peritoneal macrophages were studied. Hamster serum was shown to enhance the percentage of sporozoites tha attached to macrophages, thus confirming previous studies by other workers using mouse macrophages and mouse serum. The enhancement factor within hamster serum was concentrated by a fractionation procedure consisting of ammonium sulfate precipitation followed by Concanavalin A-Sepharose affinity chromatography. This serum fraction has been shown previously to contain component(s) that bind to P. berghei sporozoites.

Animals↗

Effects of work and acute beta-receptor blockade on myocardial noradrenaline release in congestive cardiomyopathy.

Systemic hemodynamic changes and noradrenaline concentrations in coronary sinus blood were studied at rest and during work before and after acute beta-receptor blockade. Patients with congestive cardiomyopathy were compared to patients with primary valvular diseases and to healthy subjects. Noradrenaline concentrations were higher in coronary sinus blood than in arterial blood and increased after beta blockade and during work. Noradrenaline concentrations were more increased in patients with more pronounced myocardial failure and did not seem to separate patients with congestive cardiomyopathy from those with valvular disease. Patients with congestive cardiomyopathy showed a good hemodynamic tolerance toward acute beta blockade.

Adolescent↗

Hemodynamic effects of the cardioselective beta-blocking agent metoprolol in acute myocardial infarction. A 24-hour catheterization study.

Hemodynamic changes were studied in ten patients with uncomplicated transmural myocardial infection during 24 hours on beta-blockade. The cardioselective beta-adrenergic blocking drug metoprolol was injected (15 mg i.v.) within the first 24 hours after onset of chest pain and was followed by oral therapy (25-50 mg at 6-hour intervals). There was a decrease in heart rate, systolic BP, and cardiac output, which was most marked after the injection. The stroke volume and diastolic BP for the whole group of patients remained unchanged. The pulmonary artery end diastolic pressure did not change significantly after the injection but a continuous fall was obtained in three out of four patients with initially elevated values. The preejection period, measured from the ECG and carotid pressure curve, as initially short and was prolonged in all patients after administration of the beta-blocking drug. It is concluded that the cardioselective beta-blocking drug metoprolol may be used in selected patients in the acute phase of myocardial infarction without danger of hemodynamic deterioration during the first 24 hours of therapy. The selection of patients can be based on clinical criteria. In this study signs of left heart failure, hypotension, poor peripheral circulation, bradycardia, and AV block were regarded as contraindications.

Acute Disease↗

The effect of intravenous digoxin on the occurrence of ventricular tachyarrhythmias in acute myocardial infarction in man.

Patients with acute myocardial infarction were allocated to two groups according to a double blind-system of radomization. The patients (n = 18) in one of the groups received digoxin intravenously as an injection of 0.01 mg. per kilogram of body weight during 10 minutes. The patients in the other group (n = 15) received saline and served as controls. A continuous ECG record was obtained from each patient during 1 hour preceding the administration of digoxin or saline and was continued for 3 hours following the injection. No antiarrhythmic treatment was given during the time of the study. Based on the continuous ECG, calculations were made of the relative incidence of patients with different types of ventricular tachyarrhythmias during the period of observation as well as the percentage of arrhythmia-containing 1 minute intervals observed during this period. There was no statistical difference between the incidence of ventricular tachyarrhythmias in the two groups in the 1 hour period preceding drug injection. The administration of digoxin and saline did not change the incidence of ventricular tachyarrhythmias and there was also no statistically significant difference between the two groups as regards the incidence of patients showing different types of ventricular tachyarrhythmias during the 3 hour period following drug administration, Considering the 1-minute intervals, those without any ventricular premature contractions were less in the digoxin group (92 per cent) than in the saline group (88 per cent; p less than 0.001). Serum levels of digoxin at the end of the observation period were well above what is considered the minimum therapeutic level and in three patients the level approached or reached the toxic range. In these three patients there was still no increased incidence of ventricular tachyarrhythmias. It is concluded that patients with acute myocardial infarction complicated by incipient left ventricular failure do not show an increased sensitivity to an ordinary dose of digoxin as measured by the occurrence of ventricular tachyarrhythmia.

Acute Disease↗