Search PubMed⌕ Search

Biomedical subjects

H Wesseling

Publications and source records attributed to H Wesseling.

At least 109 records · Page 6Linked to original sources
PubMed1986

Effects of intravenous captopril on inducible sustained ventricular tachycardia one week after experimental infarction in the anaesthetized pig.

The effect of captopril on inducible sustained ventricular tachycardia (VT) one week after myocardial infarction was studied in 6 Yorkshire swine. In 24 pigs, controlled myocardial infarction (MI) was produced by reversible occlusion of the left anterior descending artery during 60 minutes using an inflatable balloon catheter. Four animals died during this procedure and another 4 during the first week. After 7 days, programmed electrical stimulation (PES) was performed in the surviving animals. Seven animals showed inducible VT, which could not be terminated in one. Subsequently, intravenous captopril (0.6-1.2 mg/kg) was administered as a rapid bolus injection. PES was repeated after 5 minutes and VT was no longer inducible in all 6 pigs (P less than 0.05). Right ventricular refractoriness decreased from 253 to 228 ms (n.s.). Blood pressure and heart rate were not significantly changed. We conclude that captopril can protect the heart against PES-induced VT late after MI. It is suggested that inhibition of angiotensin II and subsequent inhibition of noradrenaline may be responsible for this effect.

Animals↗
PubMed1985

Comparison of atenolol 50 mg and 100 mg as initial treatment in uncomplicated mild to moderate hypertension.

After screening a local population in the northern part of The Netherlands for hypertension, 59 patients with a diastolic pressure (DP) between 95 and 130 mmHg were randomized and treated either with 50 mg atenolol (n = 29) or 100 mg atenolol (n = 30) for 1 month. There was no significant difference between the two treatments, neither in the fall in systolic and diastolic pressures nor in the number of complaints reported. It is concluded that in the initial treatment of uncomplicated mild to moderate hypertension, 100 mg atenolol has no advantage over a 50 mg dose.

Adult↗
PubMed1985

A comparison of labetalol and prazosin combined with atenolol in non-responders to atenolol plus hydrochlorothiazide in uncomplicated hypertension.

After screening two local populations in the northern part of The Netherlands for hypertension, patients with a diastolic pressure (DP) between 95 and 120 mmHg were treated daily either with 50 mg hydrochlorothiazide or 100 mg atenolol. Nonresponders were given the combination and if necessary the dose of atenolol was increased to 200 mg. Non-responders to the latter combination were randomized and treated either with 50 mg hydrochlorothiazide and labetalol or with 50 mg hydrochlorothiazide, 200 mg atenolol and prazosin. If after 1 month a DP less than or equal to 90 mmHg had been reached the patient was reassessed after a further 3 months. If a DP greater than 90 mmHg was found the dose of labetalol or prazosin was increased and the patient was re-examined after 1 month. This protocol was followed until the maximum dose was reached or adverse reactions prevented a further increase in dosage. During 6 months of treatment there was a further drop in systolic and diastolic blood pressures under both regimens of, respectively, 8.6 and 2.4 mmHg for labetalol, and 7.7 and 5.0 mmHg for the prazosin group. At the end of the period the average daily doses of labetalol and prazosin were 1256 mg and 4.3 mg, respectively. There was no significant difference in the average number of complaints between the labetalol and the prazosin group.

Adult↗
PubMed1985

Effects of atenolol, labetalol and propranolol on the peripheral circulation in hypertensive patients without obstructive vascular disease.

In an observer-blind, randomised cross-over trial, in 12 patients, the effects on the peripheral circulation of antihypertensive doses of atenolol, labetalol and propranolol and placebo were compared. After a placebo period of at least 4 weeks, patients were allocated at random to one of the three active drug treatments. After active treatment for at least 6 weeks and a fall in diastolic pressure (DP) to less than 90 mmHg subjects were switched to the next medication. At the end of each period, photo-electric plethysmography (PHELP) was done on all fingers of one hand cooled over 4 min in water in steps of 3 degrees C from 33 degrees to 12 degrees C, and subsequently warmed in room air (20 degrees C) for a period of 10 min. Blood flow changes during cooling were expressed as a percentage of the initial PHELP value (% PHELP). Areas under the curves, representing the % PHELP/cooling period and % PHELP/warming-up period, showed that within the temperature range normally encountered in daily life, labetalol preserved finger blood flow significantly better than propranolol and marginally better than placebo. With atenolol, finger blood flow was not significantly different from that during the three other regimens, but there were significantly fewer other side-effects. It is concluded that labetalol may be the drug of choice for hypertensive patients treated with beta-blocking agents whose peripheral arterial circulation seems inadequate at low temperatures.

Adolescent↗
PubMed1985

Haemodynamic and antiarrhythmic effects of intravenous flecainide acetate in chronic congestive heart failure.

The objective of this study was to evaluate the haemodynamic and antiarrhythmic effects of flecainide acetate in patients with heart failure. Flecainide acetate, a class Ic antiarrhythmic agent, was given intravenously to 9 patients with congestive heart failure and frequent ventricular arrhythmias with nonsustained ventricular tachycardia. The drug (2 mg/kg) was infused slowly over 60 minutes. The maximum plasma level achieved was 218 (range 142-350) ng/ml. Six of the 9 patients experienced a 90% suppression of their arrhythmias for an average of 6.5 (range 2-15) hours. Pre-ejection period control (PEPc, 148.8 +/- 3.6 msec) increased to 157 msec and pre-ejection period/ejection time (PEP/ET) [control 0.449 +/- 0.027] to 0.516 (p less than 0.005), while the ejection time index (ETI) did not change. Cardiac index (control 2.4 +/- 0.36 L/min/m2) decreased by 11% (p less than 0.02), and pulmonary wedge pressure (control 13.4 +/- 2.4mm Hg) increased by 23% (p less than 0.05). Stroke work index, arterial pressure and vascular resistance did not change significantly. The parameters returned to control values on completion of the infusion. Flecainide acetate can be safely administered at the usual dose of 2 mg/kg to patients with congestive heart failure, provided that the infusion time is doubled. Antiarrhythmic efficacy under these conditions is good even at lower plasma concentrations.

Anti-Arrhythmia Agents↗
PubMed1984

Captopril reduces purine loss and reperfusion arrhythmias in the rat heart after coronary artery occlusion.

Captopril was perfused through isolated rat hearts; its effects after local ischemia and reperfusion were assessed. Upon reperfusion all untreated (10 out of 10) but only 4 (out of 10) captopril-treated (80 micrograms/ml) hearts fibrillated (P less than 0.02). Purine overflow increased upon reperfusion but was reduced by captopril (597 +/- 62 and 333 +/- 41 nmol/min gdwt respectively; P less than 0.05). The pressure-rate index and the apex displacement were severely impaired after 30 min of reperfusion (32 +/- 16 and 10 +/- 5% respectively of initial values) but captopril reduced the injury of mechanical function (60 +/- 8; P less than 0.05 and 61 +/- 11; P less than 0.05 respectively). These results show that captopril reduces ventricular fibrillation and the loss of high energy phosphate nucleotides and thereby partly maintains mechanical function impaired by ischemia and reperfusion.

Animals↗
PubMed1984

Pharmacokinetics of the oral narcotic analgesic bezitramide and preliminary observations on its effect on experimentally induced pain.

The oral absorption of bezitramide 5 mg was studied in 7 human volunteers, using a specific radioimmuno-assay which measured both bezitramide and its active metabolite R-4618. A lag time of 0.5-1.0 h and a Cmax of 5.4 ng/ml plasma were found, the latter occurring 2.5-3.5 h after administration. The apparent elimination half-life varied from 11 to 24 h. Less than 0.3% of the dose was excreted unchanged in the urine. High concentrations in the faeces of some individuals indicate incomplete absorption and/or biliary secretion. The analgesic effect, using a standardized superficial electrical stimulation method, reached its maximum between 2.5 and 3.5 h after dosing, in accordance with the absorption phase. The duration of the effect was highly variable. Experiments in rats (n = 6, 3H-bezitramide 2.5 micrograms), demonstrated extensive biliary excretion (up to 70% of total radioactivity) and less than 3% of the label was removed by urinary excretion.

Adult↗
PubMed1984

Comparison of hydrochlorothiazide and atenolol as initial treatment in uncomplicated hypertension.

After screening a local population in the northern part of The Netherlands for hypertension, 119 patients with a diastolic pressure (DP) between 95 and 120 mmHg were randomised and treated either with 50 mg hydrochlorothiazide (n = 59) or 100 mg atenolol (n = 60). After 1 month of treatment 6 patients in the hydrochlorothiazide group and 24 patients in the atenolol group had reached a DP less than or equal to 90 mmHg (p less than 0.001). 43 of the 50 non-responders to hydrochlorothiazide were switched to atenolol and 30 of the 35 non-responders to atenolol were changed to hydrochlorothiazide. One month after the switch 19 patients in the atenolol group and 2 patients in the hydrochlorothiazide group had reached a DP less than or equal to 90 mmHg (p less than 0.001). After 6 months of treatment 32 of the 43 atenolol responders and 7 of the 8 hydrochlorothiazide responders were still receiving the same medication, as their DP was still less than or equal to 90 mmHg. Non-responders to either medication were given the combination (n = 46). 21 patients now became normotensive as did a further 10 after increasing the dose of atenolol to 200 mg. Thus, in all 70 patients had a blood pressure less than or equal to 90 mmHg after treatment for 4 months. Both drugs induced a significant reduction in the total of number of complaints after 1 month of treatment. They did not differ from each other. The reduction was seen both in responders and non-responders and persisted during treatment for 6 months. It is concluded that in terms of short-term efficacy the cardioselective, hydrophilic beta adrenoceptor-blocking drug atenolol is preferable to hydrochlorothiazide in the treatment of uncomplicated hypertension.

Adult↗
PubMed1984

Spasmodic torticollis: treatment with Tizanidine.

A randomized double-blind cross-over study was performed to compare the efficacy of Tizanidine to that of placebo in the treatment of spasmodic torticollis. No evidence was found that Tizanidine was effective in 10 patients with spasmodic torticollis who received Tizanidine during 6 weeks, up to a dose of 12 mg a day.

Adolescent↗
PubMed1983

Plasma levels of acetylsalicylic acid and salicylic acid after oral ingestion of plain and buffered acetylsalicylic acid in relation to bleeding time and thrombocyte function.

Buffered acetylsalicylic acid (Alka Seltzer, B-ASA) and plain aspirin (P-ASA) tablets were compared as to their effects on bleeding time and platelet function in eight healthy male volunteers. Two doses (500 and 1000 mg) of each preparation were investigated in a cross-over design, each volunteer being his own control in each dose group (n=4). Both preparations disturbed platelet aggregation to the same extent. Bleeding time increased after both preparations, though significantly more after the buffered preparation than after plain acetylsalicylic acid, irrespective of the dosage. The 1000 mg dose prolonged bleeding time significantly more than the 500 mg dose, irrespective of the preparation. Kinetic analysis showed that B-ASA gave higher peak plasma levels of acetylsalicylic acid (ASA) and accordingly salicylic acid peak levels were also higher after the buffered preparation. It is concluded that B-ASA in equi-analgesic doses prolongs bleeding time more than the plain preparation. Since it is less agressive on the gastro-intestinal mucosa, its use may be advantageous in situations where acetylsalicylic acid induced loss of platelet aggregation is desired. However, the risk of prolonged bleeding--e.g. after tooth extractions--is probably higher after the buffered preparation.

Adult↗
PubMed1983

Use of cimetidine; parallels and discrepancies between the views of drug regulatory agencies and practicing physicians.

The use of cimetidine in general practice was studied in relation to the guidelines approved by the Dutch National Drug Regulatory Agency (DRA). National and regional figures showed that the frequency with which cimetidine was prescribed in general practice was greater than could be explained on the basis of approved indications alone. Analysis of its employment in 14 hypothetical cases suggested however, that general practitioners in The Netherlands chose their indications for cimetidine and the duration of cimetidine treatment according to the guidelines for its use approved by the DRA; only 12.7% of the prescriptions related to indications that had not been approved in The Netherlands, the most prominent finding being the case of a possible gastric carcinoma. It was estimated that less than half of all cimetidine prescriptions in general practice will be issued for indications approved by the Dutch DRA. Some discrepancy exists with regard to the dose employed; contrary to the recommendations of the DRA, the dose chosen varied little from indication to indication.

Cimetidine↗
PubMed1982

Comparison of labetalol, propranolol and hydralazine in hypertensive out-patients.

In a randomized cross-over trial the combination labetalol/hydrochlorothiazide was compared with the combination of propranolol/hydralazine/hydrochlorothiazide in 34 uncomplicated hypertensive patients, who were not satisfactorily controlled with hydrochlorothiazide 50 mg alone. The elevated diastolic pressure (D.P.) in 27 patients responded satisfactorily to the labetalol schedule and in 28 patients to the propranolol/hydralazine schedule. No difference was found in the rate of decrease of D.P., nor in the disappearance of hypertension-related complaints. Although the duration of the washout between treatments was at least one month, treatment was significantly more efficacious during the second period. Labetalol pre-treatment especially seemed to enhance the effect of subsequent propranolol/hydralazine administration. Side effects due to therapy were rare and were not related to any particular treatment. The median daily dose of labetalol in responders was 600 mg and that of propranolol/hydralazine 120/60 mg (in both therapies hydrochlorothiazide 50 mg was given in addition). Patients showed a slight preference for the labetalol medication. It is concluded that labetalol/hydrochlorothiazide and propranolol/hydralazine/hydrochlorothiazide are equally satisfactory in the treatment of uncomplicated hypertension.

Adult↗
PubMed1982

An electroencephalographic study of 4-aminopyridine.

The electroencephalographic (EEG) effects of 4-aminopyridine (4-AP) given intravenously in therapeutic doses were studied in four conscious human volunteers. 4-AP (0.2 mg/kg) caused an increase of the occipital alpha peak frequency of 0.4 to 1.0 Hz. In the dose range of 0.2 to 0.3 mg/kg there was neither evidence for epileptic activity in the EEG nor were any clinical side effects observed. This dose of 4-AP was also found to antagonize diazepam-induced sleep in four volunteers. In addition 4-AP (0.3 mg/kg) hastened the recovery by a factor of 4 in four patients having endoscopic procedures under diazepam-nitrous oxide anesthesia.

4-Aminopyridine↗