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Biomedical subjects

J Bonelli

Publications and source records attributed to J Bonelli.

At least 37 records · Page 2Linked to original sources
PubMed1982

Stress, catecholamines and beta-blockade.

In order to investigate the effects of beta-blockade on haemodynamic response to stress, 2 groups of volunteers received either propranolol or mepindolol sulphate under basal conditions and under the stress of mental arithmetic. In control conditions, increases occurred in heart rate (HR), cardiac output (CO) and systolic and diastolic blood pressure in response to calculation stress. Stress-induced increases in HR and CO were significantly reduced by propranolol. Systolic blood pressure during calculation stress under propranolol was slightly less than in control conditions. However, diastolic blood pressure under stress was higher with propranolol than in the control study. Mepindolol sulphate also reduced HR and CO under calculation stress but it produced no significant change in diastolic pressure. A significant increase in plasma adrenaline occurred under stress. The level was not altered by propranolol but was reduced to less than 50% of the untreated stress value by mepindolol. Since beta-blocking agents suppress an increase in heart rate in stressful situations but either fail to prevent or even potentiate increased diastolic pressure, their use in patients without hypertension should be reserved for those showing pathological stress reactions. They do not appear to be indicated for the management of stressful situations in general.

Adrenergic beta-Antagonists↗
PubMed1982

Relevance of selectivity and non-selectivity in beta-adrenoceptor blocking drugs.

1 The heart rate responses to increasing doses of isoprenaline (n = 6) (during infusion with atropine 0.5 mg/min i.v.) and noradrenaline (n = 5), (during infusion with phentolamine 160 mg/h i.v.) were recorded before and after the intravenous administration of propranolol (15 mg) or metoprolol (15 mg). 2 In the doses used, metoprolol was less potent than propranolol in antagonizing isoprenaline-induced tachycardia, during atropine infusion. 3 In volunteers treated with phentolamine both metoprolol and propranolol produced similar inhibition of noradrenaline-induced tachycardia, indicating comparable beta 1-adrenoceptor blockade in the doses used. 4 The fact that the shift of the dose-response curve of isoprenaline-induced tachycardia was smaller after metoprolol than after propranolol supports the hypothesis that beta 2-adrenoceptors are present in the heart.

Adrenergic beta-Antagonists↗
PubMed1982

Duration of the hypotensive effect of guanfacine.

Guanfacine given intravenously causes a brief rise in blood pressure. This is followed by a sustained decrease of blood pressure, accompanied in one case by a marked orthostatic effect. In addition to its lowering effect on blood pressure, guanfacine also reduces heart rate. The duration of action for up to 72 h is due to the long half-life of the drug. The main side effects observed are fatigue and sedation.

Adult↗
PubMed1981

[Pharmacokinetics of beta-methyldigoxin and beta-acetyldigoxin in patients with cirrhosis of the liver (author's transl)].

In this prospective randomised study 12 patients suffering from cirrhosis of the liver (stable phase) and 12 healthy male volunteers were treated with either 0.3 mg beta-methyldigoxin (Lanitop) or 0.4 mg beta-acetyldigoxin (Novodigal) daily, orally. Every day the total serum digoxin concentrations of the patients and volunteers were measured by radioimmunoassay. Both digoxin and beta-methyldigoxin are measured by this method. In subjects receiving beta-methyldigoxin therapy the ratio of beta-methyldigoxin to digoxin in the serum was determined by liquid chromatography. The digoxin levels in patients with cirrhosis treated with beta-methyldigoxin were statistically significantly higher than in healthy volunteers. In patients with cirrhosis the proportion of serum beta-methyldigoxin averaged 77.7% of the total digoxin concentration, whereas the proportion was only 37.5% in healthy volunteers. With beta-acetyldigoxin there was no statistically significant difference between patients with cirrhosis and healthy volunteers. Alterations in pharmacokinetics may cause the higher total serum digoxin concentrations in cirrhotic patients. The following factors seem to be important: longer elimination half life, changes in distribution volume and reduced renal clearance. There is greater danger of digitalis toxicity in patients with cirrhosis of the liver on standard dosage of beta-methyldigoxin than on standard dosage of beta-acetyldigoxin.

Acetyldigoxins↗
PubMed1981

Digoxin concentration in cerebrospinal fluid-a study carried out after 9 days of treatment of beta-methyldigoxin or beta-acetyldigoxin.

Two groups of seven healthy volunteers were treated for 9 days with either 0.3 mg beta-methyldigoxin or 0.4 mg beta-acetyldigoxin daily, applied orally. On the 10th day, digoxin concentrations in plasma and cerebrospinal fluid (CSF) were determined by radioimmunoassay. After therapy with beta-methyldigoxin the plasma/CSF digoxin concentration ratio was 3.7:1; after therapy with beta-acetyldigoxin it was 3.2:1. There was no significant difference in the plasma/CSF digoxin concentration ratio after 9 days of treatment with equipotent doses of beta-methyldigoxin and beta-acetyldigoxin.

Acetyldigoxins↗
PubMed1981

Cardiovascular effects of diltiazem in healthy volunteers at rest, supine and erect, and during physical and mental stress.

The hemodynamic effects of diltiazem were investigated in six volunteers at rest, supine and erect, under psychologic stress and orthostatic conditions. Plasma concentrations were also estimated. Under all conditions diltiazem showed a vasodilating property that was more pronounced on the arterial resistance vessels than on the pulmonary vessels. The first plasma concentrations were detected 15 min after drug intake, and the highest values were seen at the end of the study in the 3rd h.

Adult↗
PubMed1980

[Haemodynamic effects after application of nitroglycerin sublingually or as ointment in patients with left ventricular heart failure (author's transl)].

The haemodynamic effects of a 2% nitroglycerin ointment and of sublingual nitroglycerin in patients with left ventricular heart failure were investigated. The well-known pulmonary blood pressure and pulmonary wedge-pressure lowering effect were observed with both forms of administration. Differences exist between onset and duration of the haemodynamic effects. With sublingual administration of nitroglycerin the peak effect was seen after 5 minutes, whilst the pulmonary blood pressure rose again 30 minutes later. After application of nitroglycerin ointment a peak effect was seen 30 minutes later and the effects were sustained for 3 to 6 hours.

Administration, Oral↗
PubMed1980

Haemodynamic effects of guanfacine.

1. The haemodynamic mechanism of action of guanfacine 4 mg intravenously was investigated in resting conditions and during exercise for up to 20 h after administration of the drug. Cardiac output and pulmonary arterial pressure were determined by the Swan-Ganz thermodilution method. Blood pressure was measured directly. 2. During and immediately after intravenous administration of guanfacine, blood pressure peripheral resistance and pulmonary arterial pressure increased (in keeping with an alpha-sympathomimetic effect of the compound), whereas heart rate and cardiac output decreased. 3. Subsequently blood pressure fell as a result of a decrease in cardiac output. From the third hour peripheral resistance decreased, whereas cardiac output increased again, sometimes exceeding the control value. 4. During exercise blood pressure was reduced from the third hour after administration, as in resting conditions, as a result of the reduction in peripheral resistance. 5. In resting conditions guanfacine reduced heart rate at the beginning and during the whole course after administration of the drug. 6. Side-effects noted included fatigue, drowsiness and bradycardia.

Antihypertensive Agents↗
PubMed1980

Pharmacokinetics and pharmacodynamics of mepindolol sulphate.

Five clinically healthy, male volunteers were each given an intravenous dose of 1.19 mg of 2-methyl-14C-mepindolol sulphate, followed one week later by an oral dose of 20 mg. In addition, the effect of mepindolol sulphate was studied in 3 male test subjects after repeated oral administration for 8 days with a daily dose of 2 x 2.5 mg using the heart rate behaviour model during submaximum ergometer exercise. Synchronously with pharmacodynamics, pharmacokinetic data were also obtained after multiple dosing.

Administration, Oral↗
PubMed1979

[A double blind cross-over study with mepindolol-sulfate in patients with coronary heart disease (author's transl)].

UNLABELLED: The effect of mepindolol-sulfate (2 x 2.5 mg) was tested in 20 patients with coronary heart disease in a controlled study against placebo resp. propranolol (3 x 40 mg). RESULTS: 1. The frequency and intensity of anginal attacks were reduced significantly under mepindolol-sulfate therapy.-- 2. There was a significant improvement of ergometric exercise tolerance under mepindolol-sulfate therapy.--3. Additionally a reduction of ST-depression in ECG was found under mepindolol-sulfate.--4. In patients with coronary heart disease the clinical effect of mepindolol-sulfate in a daily dose of 2 x 2.5 mg was equal to propranolol in a daily dose of 3 x 40 mg.

Adrenergic beta-Antagonists↗
PubMed1979

[Digitalis therapy in practice: correlation between clinical evaluation and plasma digoxin concentration (author's transl)].

In a prospective study 73 patients on maintenance digitalis treatment at the Paracelsus Institute, Bad Hall, were clinically examined and the dosage of the drug was adjusted according to cardiac symptoms. The clinical effects were correlated to digoxin concentrations measured on the day following admission to hospital and on the 21st day of treatment. The following practical conclusions were reached: 1. More than 50% of the patients were underdigitalized. 2. There is often no indication for digitalis therapy in patients with a low daily maintenance digoxin dosage and normal renal funciton. 3. The usual recommended maintenance dosage of digoxin provides serum digoxin levels in the lower region of the therapeutic range. 4. Patients with symptoms of decompensation taking an average dosage of digoxin need more digitalis. There is generally no danger of toxicity when the dosage is increased. 5. The serum digoxin concentration in patients with slightly reduced renal function lies in the upper region of the therapeutic range with usual doses of digoxin.

Arrhythmias, Cardiac↗
PubMed1979

Effect of calculation stress on hemodynamics and plasma catecholamines before and after beta-blockade with propranolol (Inderal) and mepindolol sulfate (Corindolan).

The effect of calculation stress on hemodynamic parameters and plasma adrenalin and noradrenalin was studied in two groups of 6 male subjects, before and during beta-Blockade. One group received propranolol 15 mg i.v. and the other received mepindolol sulphate 0,5 mg i.v. There was an increase in heart rate, cardiac output and blood pressure during mental stress. A significant increase in plasma adrenalin but not in noradrenalin occurred at the same time. The stress-induced rise in HR but not that in blood pressure could be prevented by beta-receptor blockage with propranolol and mepindolol sulfate. The peripheral resistance (PR) and diastolic blood pressure in stress were even higher after propranolol than in the control study. Propranolol had no effect on the increased adrenalin concentration during stress, but it was prevented by mepindolol sulfate. There was no correlation between the increase in HR and that in adrenalin during stress, but the HR in stress and the HR reaction to infused isoproterenol were highly correlated.

Blood Pressure↗
PubMed1979

[Pulmonary function tests with the bronchodilator Terbutaline].

The acute bronchodilator effect of the beta 2-adrenoceptor agonist terbutaline was tested single-blind cross-over in out-patients with chronic obstructive airways disease (intrinsic asthma). In 7 series comparisons were made with other marketed bronchodilators. Airways resistance was measured by whole body plethysmography. In another 3 series the effect on heart rate of terbutaline and other adrenocepter agonists was tested in healthy volunteers. Terbutaline and the adrenoceptor agonists clenbuterol, epinephrine, fenoterol, hexoprenaline, isoprenaline, metaproterenol, reproterol and salbutamol, the vagolytics atropine, ipratropium bromide and AA 22-263, the xanthinederivative theophylline ethylenediamine and one combined substance drug were used.

Administration, Oral↗
PubMed1979

[Hemodynamics in patients suffering from hyperkinetic cardiac syndromes and in normal persons under psychological stress before and after treatment with propranolol (author's transl)].

In patients with hyperkinetic heart syndrome we found at rest a higher heart rate, a higher stroke volume and a higher cardiac output than in normal volunteers. Therefore blood pressure is high although peripheral resistance is lower than in normals. Similar circulatory differences were found under conditions of mental stress. After beta-adrenergic blockade with 15 mg Propranolol heart rate and cardiac output decrease, whereas peripheral resistance increases. Mean blood pressure thus remains unchanged. Even after beta-adrenergic blockade circulatory differences between normals and patients with hyperkinetic heart syndrome are seen. The possible causes of these differences are discussed.

Blood Pressure↗
PubMed1979

Hemodynamic changes in hypertensive patients at rest and during physical exercise before and after acute i.v. administration of bufuralol-HCl or propranolol.

The hemodynamic effects of 20 mg Bufuralol-HCl and of 15 mg Propranolol given to hypertensives i.v. at rest and under physical exercise conditions were examined. It could be shown that Bufuralol-HCl lowered the diastolic BP and PR at rest already in the acute experiment, contrary to Propranolol. Under physical exercise conditions the diastolic BP is lowered, the PR remains unchanged in spite of reduced CO. After exclusion of other possible explanations, Bufuralol-HCl may lower the diastolic BP acutely at least partly by inhibition of cerebral beta-receptors. A faster and better liquor diffusion could be the reason for these results. It can be assumed that the acute BP lowering effect is mediated by the same mechanism as the chronic effect of the other beta-receptor blocking drugs.

Adrenergic beta-Antagonists↗
PubMed1979

Hemodynamic characterization of bufuralol-HCl and pindolol based on the competitive effects of isoproterenol.

In this hemodynamic study a new beta-receptor blocker, Bufuralol-hydrochloride was compared with Pindolol under an Isoproterenol infusion with increasing doses in healthy male volunteers. We found the following results: 1. Before Isoproterenol peripheral resistance increased after acute i.v. application of Pindolol but decreased after Bufuralol-hydrochloride i.v. application. 2. After beta-receptor blockade with either Bufuralol-hydrochloride or with Pindolol a shift to the right of the dose effect relationship concerning heart rate and cardiac output under Isoproterenol infusion was observed, indicating beta 1-blockade. 3. The reduction of peripheral resistance which is usually observed as a sign of beta 2-blockade was also shifted to the right under the influence of both drugs. 4. This proves Bufuralol-hydrochloride to be a non-specific beta-blocking agent with an affinity to the beta 1- and beta 2-receptors. 5. Although Bufuralol-hydrochloride has a beta 2-blocking property which is even more pronounced than that of Pindolol, it reduces acutely, intravenously given, peripheral resistance.

Adrenergic beta-Antagonists↗