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Biomedical subjects

J Wikstrand

Publications and source records attributed to J Wikstrand.

At least 145 records · Page 8Linked to original sources
PubMed1983

Increased cardiac output and lowered peripheral resistance during metoprolol treatment.

Echocardiography was performed at every six months in hypertensives well controlled on metoprolol, 100 mg twice a day. After six months' treatment blood pressure was reduced from 177/110 mm Hg to 147/88 (p less than 0.02). LV wall thickness (septum + posterior wall) was unchanged 2.10 cm (2.14), and a significant drop in cardiac output (CO) to 5.0 l/min (6.1, p less than 0.02) was recorded (pretreatment values in brackets). After 24 months' treatment LV wall thickness was reduced to 1.94 cm (p less than 0.02), total peripheral resistance (TPR) to 17.3 mm Hg/l/min (23.4, p less than 0.02) and CO increased to 6.7 l/min (6.1, n.s.). After six months' treatment, there was thus a drop in BP with a significant drop in CO and unchanged TPR. After 24 months' treatment, however, CO was back to the pretreatment level and the drop in BP was entirely caused by a drop in TPR which was probably secondary to a reduction in the wall thickness of the arterial resistance vessels as judged by the relationship between the reduction in wall thickness in the LV and the reduction in TPR during the treatment.

Adult↗
PubMed1983

Left ventricular mass in middle-aged men. Relationship to blood pressure, sympathetic nervous activity, hormonal and metabolic factors.

Left ventricular (LV) mass was studied echocardiographically in 120 middle-aged men representing a wide range of blood pressures (BP) and its relation to the following factors was analysed: BP measured in different resting situations and during isometric exercise, 24 hour urinary noradrenaline excretion and plasma noradrenaline, plasma renin activity, plasma angiotensin II, plasma aldosterone, blood glucose and plasma insulin. Each BP measurement showed weak but significant correlation with LV mass in the entire study group. In the upper BP range only BP measured during isometric exercise was correlated with LV mass. In the upper BP range there were also significant correlations between both the 24 hour urinary noradrenaline excretion and plasma aldosterone and LV mass, while blood glucose and plasma insulin were significantly correlated with LV mass in the intermediate BP range. Thus there was a surprisingly low correlation between LV mass and arterial BP. The findings regarding sympathetic nervous activity, hormonal and metabolic factors might indicate that these factors are involved in the pathogenesis of an increased LV mass in some individuals with essential hypertension.

Angiotensin II↗
PubMed1982

Electrically induced short-lasting tetanus of the calf muscles for prevention of deep vein thrombosis.

Electrical calf muscle stimulation during surgery has been used for the prevention of deep vein thrombosis (DVT) with varied results in several studies. This effect is mainly achieved by the reduction of venous stasis in the legs. Another possible beneficial effect might be an increased fibrinolytic activity of the blood secondary to the muscle contractions. Previously, single electrical impulses have been used for stimulation, giving rise to 'single twitches' in the muscles. In the present study the effect on calf volume of muscle stimulation with groups of impulses giving a short-lasting tetanus was investigated. Changes in calf volume were recorded by strain gauge plethysmography. Optimal values for duration, number and frequency of the impulses within the groups were determined. Stimulation with groups of impulses reduced calf venous volume approximately three times more efficiently than stimulation with single impulses. Calf muscle stimulation did not enhance the increase in fibrinolytic activity of venous blood observed after oesophago- or laryngoscopies under general anaesthesia.

Adult↗
PubMed1982

Prediction and prophylaxis of postoperative thromboembolism--a comparison between peroperative calf muscle stimulation with groups of impulses and dextran 40.

The effects of peroperative electrical calf muscle stimulation with groups of impulses giving a short lasting tetanus of the calf muscles on postoperative deep venous thrombosis (DVT) and pulmonary embolism (PE) were compared with that of dextran 40 given per and postoperatively. The incidence of DVT and PE during the first 4-6 postoperative days was recorded. The diagnosis of DVT was based on the 125I-fibrinogen uptake test and phlebography and of PE on pre- and postoperative perfusion pulmonary scintigram and chest X-ray examination. Both methods reduced the incidence of PE. Calf muscle stimulation reduced the DVT incidence in patients with malignant disease while the reduction in DVT incidence for the whole group only was significant in the stimulation as well as the dextran 40 group. Mean values for preoperatively determined levels of antithrombin III, beta-thromboglobulin, fibrinopeptide A, plasminogen and ability to release fibrinolytic activity during venous stasis did not differ between those patients who developed or those who did not develop postoperative DVT or PE. However, antithrombin III levels below 80 per cent appeared to predispose to postoperative thromboembolism. The two prophylactic methods have similar effects on the incidence of postoperative thromboembolism. The stimulation method has certain advantages due to its safety and simplicity.

Adult↗
PubMed1982

Effects of prenalterol administered orally in patients with congestive heart failure.

A single-blind study of prenalterol 20-200 mg daily in a slow-release tablet preparation and a placebo was performed in 15 patients with moderate to severe congestive heart failure (NYHA II-IV) to evaluate the haemodynamic and clinical effects of oral prenalterol. Non-invasive parameters in the measurement of cardiac output, stroke volume, pre-ejection period index (PEPI), PEP/LVET ratio, ejection fraction and mean Vcf were significantly improved, indicating beneficial effects of prenalterol on cardiac contractility. Systolic blood pressure, heart rate and rate-pressure product were slightly increased at rest but were considerably lower during exercise. Arrhythmogenecity was not seen in the patients studied. Subjective improvement was noted in the majority of patients as evidenced by a decreased frequency of dyspnoea, fatigue and angina. Unwanted effects, such as palpitations and transmitted arm pulsations, were transient and disappeared with dose adjustment, while the inotropic effect of the medication was maintained. The clinical response appeared to be sustained for up to 2 weeks of treatment, indicating non-development of tachyphylaxis.

Administration, Oral↗
PubMed1982

Blood pressure in relation to the renin-angiotensin-aldosterone system.

The relationship between blood pressure (BP) and the renin-angiotensin-aldosterone system was studied in a stratified random sample (n=120) of 49-year-old men selected from a BP screening and covering a wide range of BPs. Only subjects not on antihypertensive treatment were included. None had malignant or secondary hypertension. Plasma renin activity, plasma concentrations of angiotensin II, aldosterone, sodium, potassium and noradrenaline and the 24-hour urinary excretions of sodium, cortisol and noradrenaline were determined. Of these variables, only p-aldosterone was significantly correlated wtih BP, both in the whole study group (R=0.22, p less than 0.02, n=119) and in the subjects with the highest BP range (R=0.36, p less than 0.02, n=30). Of the clinical groups compared, the hypertensive subjects had significantly higher mean p-aldosterone than the borderline and normotensive subjects. Multiple regression analysis showed that the 24-hour urinary excretion of noradrenaline was the factor most strongly correlated to p-aldosterone, suggesting that the sympathetic nervous system might stimulate aldosterone secretion. Our findings indicate that aldosterone may be of importance for the development and maintenance of essential hypertension.

Aldosterone↗
PubMed1981

Blood pressure and the renin--angiotensin--aldosterone system.

1. The relationships between blood pressure and the components of the renin--angiotensin--aldosterone system were studied in 49-year-old men (n = 120) who were selected at random from the total population so as to be representative of all blood pressure levels. 2. Only plasma aldosterone concentration was significantly correlated with blood pressure, both in the whole study group (r = 0.22; P less than 0.02) and in the hypertensive blood pressure range (r = 0.36; P less than 0.02). The hypertensive subjects had a significantly higher plasma aldosterone concentration than the borderline and normotensive subjects. 3. Multiple regression analysis including factors related to the renin--angiotensin--aldosterone system, showed that the 24 h urinary excretion of noradrenaline was the factor most strongly correlated to plasma aldosterone. 4. The findings indicate that aldosterone may be the most important component of the renin--angiotensin--aldosterone system in the development and maintenance of essential hypertension.

Aldosterone↗
PubMed1980

Blood pressure and renal function.

The relationship between blood pressure (BP) and renal function was studied in samples of 49-year-old men. Of 3 205 49-year-old men, 2 376 (74%) took part in a BP screening. By systematic sampling, based on diastolic BP levels varying from very low to very high, 120 subjects were selected for this study. Only subjects who were not on antihypertensive treatment were included. Renal blood flow (RBF), renovascular resistance (RVR), glomerular filtration rate (GFR), filtration fraction (FF) and renal concentrating capacity were studied in 111 subjects, none of whom had advanced hypertension. With increasing BP there was a decrease in RBF (r = -0.34) and an increase in RVR (r = 0.81) and FF (r = 0.35). The changes in renal haemodynamics occurred gradually from low to high BP, and did not start at any particular BP level. With increasing BP, GFR was unchanged. An "autoregulation of GFR" was thus found at all BP levels studied. Renal concentrating capacity was unchanged. These findings indicate that renal haemodynamics in essential hypertension are adjusted mainly to ensure a constant GFR.

Blood Pressure↗
PubMed1979

Haemodynamic effects and pharmacokinetics of a new selective beta1-adrenoceptor agonist, prenalterol, and its interaction with metoprolol in man.

The haemodynamic effects of the selective beta1-adrenoceptor agonist prenalterol were studied in healthy subjects before and after therapeutic doses of the selective beta1-adrenoceptor blocker metoprolol. Plasma levels of the drugs were also determined in order to calculate certain pharmacokinetic variables. Intravenous infusion of prenalterol 0.13, 0.25 and 0.50 mg induced a dose-dependent decrease in total electromechanical systole (QA2) and pre-ejection period (PEP). The effect on left ventricular ejection time (LVET) was not significant. Increases in systolic blood pressure and heart rate were dose-dependent. Diastolic blood pressure did not change significantly. When metoprolol had been administered in a cumulative dose of 150 mg (mean maximal plasma level, 284 nmol/l) prenalterol had to be administered in doses that were twelve times higher than before the beta-blocker in order to induce the same haemodynamic effects. Prenalterol was rapidly distributed with an average half life of 8 min. This indicates that distribution equilibrium will be achieved within 30 min after intravenous administration. The overall elimination rate in the post-distributive phase corresponded to an average half life of 2.0 h.

Adrenergic beta-Agonists↗
PubMed1979

Effect of treatment of hypertension in the primary preventive trial, Göteborg, Sweden.

1 A treatment group comprising 635 hypertensive men (casual SBP greater than 175 or DBP greater than 115 twice) was compared with a reference group (n = 391 men; casual SBP greater than 175 or DBP greater than 115 only at screening). All men belonged to the same population sample of 7,455 men aged 47-54 yr. 2 The two groups did not differ with respect to age, smoking habits or cholesterol values, but screening BPs were higher in the treatment group. 3 During 4.3 years' follow-up there was a significantly lower total death rate in the treatment group compared with reference group. 4 There was also a strong tendency towards lower incidence of non-fatal myocardial infarction (P = 0.06). The pooled incidence of non-fatal myocardial infarction and fatal CHD was lower in the treatment group than in the reference group (P less than 0.03).

Adrenergic beta-Antagonists↗
PubMed1979

Heart and kidney involvement and prognosis in hypertension. A study concerning referred hypertensive patients and hypertensive patients found by blood pressure screening.

Severity of hypertension, frequency of secondary hypertension and prognosis have been compared in two groups of hypertensive men. The first group (n=686) was taken from a blood pressure screening of a total population sample. The other group (n=154) consisted of hypertensive men, referred to a hypertension clinic by physicians. The mean age of the groups was the same, (X=52 years, range 46--59 years). All went through the same investigations and were followed up and treated in a similar way at the hypertension clinic. The referred men had more severe hypertension, as shown by significantly more heart and kidney involvements. They also had a higher incidence of myocardial infarction, implying a poorer prognosis with regard to cardiovascular disease. The analysis shows the importance of a detailed description of studied groups, not only in terms of blood pressure, age and sex, but also with respect to the frequency and degree of present and previous signs of heart and kidney involvement. With such a description it is possible to compare results from different studies regarding pathophysiological mechanisms and the effect of treatment in hypertension.

Cerebrovascular Disorders↗