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Biomedical subjects

T Hedner

Publications and source records attributed to T Hedner.

At least 307 records · Page 17Linked to original sources
PubMed1987

The rationale for ketanserin therapy in hypertension.

The rationale for ketanserin therapy in hypertension is reviewed against the background of known physiological and pathophysiological effects of serotonin. The usefulness of the serotonin (5-HT2) antagonist ketanserin in the treatment of hypertension is evaluated with respect to its known antihypertensive property as well as in relation to its effect on hypertension-induced cardiovascular changes, platelet hyperreactivity, and atheroma formation. Based on ketanserin's documented antihypertensive effect and also on its potentially positive effect on cardiovascular mortality via other mechanisms, it would appear that ketanserin could offer a highly rational approach to the treatment of hypertension and its risks in the future.

Animals↗
PubMed1987

Cardiovascular effects of ketanserin during cold pressure and during isometric and dynamic exercise in hypertensive patients.

Ketanserin is an arteriolar vasodilator, acting on serotoninergic (5-HT2) and adrenergic (alpha 1) receptors. In animals, ketanserin exerts a centrally mediated inhibition of sympathetic nerve activity. In humans it is not established whether ketanserin reduces basal or reflex increases in sympathetic outflow. In different groups of patients, we have investigated the cardiovascular response as well as plasma noradrenaline (pNA) during rest, during the cold pressure test (0 degree C for 3 min), and during isometric (handgrip), and/or dynamic exercise in order to see whether ketanserin reduces the normal increase in sympathetic tone during these maneuvers. Twenty-one patients with essential hypertension were given oral ketanserin (40 mg) once or twice daily for 4 weeks after a 2-4-week single-blind control period. Ketanserin significantly lowered systolic and diastolic blood pressure as well as heart rate during rest. Resting pNA was not significantly reduced, but the change in pNA was significantly correlated to the reduction in blood pressure and heart rate. During exercise, blood pressure and heart rate remained reduced. Moreover, the relative increase in systolic blood pressure during handgrip and the relative increase in heart rate during bicycle ergometry were significantly reduced during ketanserin therapy. During isometric exercise the relative reduction in blood pressure was significantly correlated to the relative reduction in pNA.

Aged↗
PubMed1987

Effects of lidocaine infusion on the sympathetic response to abdominal surgery.

Activation of afferent nerves in the area of surgery is a cause for surgical pain and stress. Intravenous (IV) lidocaine has been shown to inhibit postoperative pain. In the present double-blind study, the effects of a continuous IV infusion of lidocaine (2 mg/min) on the sympathoadrenal stress response to surgery were evaluated in 38 patients scheduled for elective cholecystectomy who were randomly assigned to two groups. In one group, lidocaine infusion was started 30 min before the operation and continued for 24 hr after surgery (n = 18). In the second group (n = 20), saline was infused. The increases in heart rate and blood pressure after tracheal intubation were not significantly different between the groups, but tachycardia and hypertension associated with extubation was prevented in patients given lidocaine. Differences in blood pressure and heart rate between the two groups were otherwise not significant intra- or postoperatively, nor were differences in blood glucose or plasma catecholamine concentrations during the first 24 hr after skin incision. Urinary catecholamine concentrations did not differ significantly in the two groups during the first postoperative day, but during the second postoperative day urinary output of epinephrine and norepinephrine were significantly less in the group of patients receiving lidocaine infusion. It was concluded that the IV infusion of lidocaine during and after major abdominal surgery suppresses extubation-induced hypertension and tachycardia but does not inhibit the general sympathetic response during the first postoperative day. However, lidocaine infusion reduces urinary output of catecholamines during the second postoperative day, suggesting a more rapid decline in the sympathoadrenal response postoperatively in the experimental group.

Adrenal Medulla↗
PubMed1986

Acute volume expansion as a physiological stimulus for the release of atrial natriuretic peptides in the rat.

The concentration of immunoreactive atrial natriuretic peptide(s) (ANP) was measured in normovolemic conscious rats and 15 min after 10% and 20% blood volume expansion. A 20% blood volume expansion caused a 2-fold increase in plasma ANP. While plasma ANP increased linearly, atrial levels of ANP remained unaltered. The increase in plasma ANP parallelled increases of central blood volume and central venous pressure. It is concluded that acute blood volume expansion is a major physiological stimulus for the release of atrial natriuretic peptides into the circulation.

Animals↗
PubMed1986

Characterization of the antinociceptive effects of some adenosine analogues in the rat.

The antinociceptive effects of the stable adenosine analogues N6-phenylisopropyladenosine (L-PIA), N6-cyclohexyladenosine (CHA) and 5'-N-ethylcarboxamidoadenosine (NECA) were investigated in conscious rats using cutaneous thermal tests (hot plate and tail flick). Subcutaneous administration of the adenosine analogues induced a dose-dependent antinociceptive response for all agents. However, NECA was approximately 15 times more potent than PIA and CHA. Approximately the same potency order and response was seen when the adenosine analogues were administered intrathecally at the lumbar level. By this route of administration, the adenosine analogues were approximately 10-20 times more potent than after S.C. administration. Intracerebroventricular administration (lateral ventricles), however, induced a variable response, in most cases a slight hyperalgesia. The nonspecific adenosine antagonist theophylline (S.C.) rapidly reduced the antinociceptive effect induced by PIA (S.C.) but enprofylline, a bronchodilating xanthine with low ability to antagonize adenosine did not influence PIA-induced antinociception. It is concluded that stable adenosine analogues and presumably adenosine itself have potent antinociceptive effects via specific adenosine receptors in the rat. The effects seem to be mediated mainly by a spinal mechanism of action.

Adenosine↗
PubMed1986

Treatment of essential hypertension with felodipine in combination with a diuretic.

In a double-blind cross-over study, the effect on blood pressure (BP), heart rate (HR) and plasma noradrenaline concentration (pNA) of placebo or felodipine given in addition to hydrochlorothiazide was studied in 12 male patients with essential hypertension, not satisfactorily controlled with the diuretic alone. The first dose of felodipine decreased BP and increased HR for about 6 h. After 4 weeks of treatment with felodipine, BP was reduced for 24 h, whereas HR was only transiently increased. The elimination half-life of felodipine was about 23 h. The plasma noradrenaline concentration increased after felodipine and serum uric acid decreased. Side-effects were few and usually mild.

Blood Pressure↗
PubMed1986

Extradural morphine: influence of adrenaline admixture.

The influence of the addition of adrenaline on extradural morphine analgesia and pharmacokinetics was investigated in a double-blind study. Morphine 2 mg was administered to 14 patients undergoing thoracotomy. In addition, adrenaline 50 micrograms added to the extradural solution, was administered to half of the patients, selected randomly. Morphine concentrations in serial plasma and cerebrospinal fluid (CSF) samples were measured. Postoperative analgesia was estimated by determining the requirement for additional analgesics. Following extradural administration of plain morphine, the peak morphine concentrations in CSF were 22 +/- 5 (SEM) times those in plasma; during the elimination phase the CSF concentrations exceeded those in plasma by about 150 times. The area under the concentration v. time curve (AUC) was 162 +/- 27 (SEM) times larger in CSF than in plasma. The admixture of adrenaline with the extradural morphine increased the individual variability in CSF and plasma concentrations. However, compared with the plain morphine group, adrenaline did not significantly increase the concentrations of morphine in CSF, nor were the morphine concentrations in plasma significantly decreased. The duration of analgesia was related to the amount of morphine in CSF, that is AUC (P less than 0.05) and peak concentrations of morphine in CSF (P less than 0.05).

Aged↗
PubMed1986

Increased plasma levels of atrial natriuretic peptide in patients with congestive heart failure.

Atrial natriuretic peptide (ANP) is a recently discovered hormone, originating from atrial myocardium. The peptide (or family of peptides) induces potent diuretic/natriuretic, vasorelaxing and aldosterone inhibitory effects. We have investigated plasma concentrations of immunoreactive ANP in 10 patients with congestive heart failure (CHF). Mean plasma ANP concentrations were more than three times higher in CHF patients than in a matched control group. High plasma ANP concentrations in pathophysiological conditions with a high preload combined with salt and water retention is consistent with a physiological role of this hormone to correct hypervolemia by causing natriuresis and diuresis. It is concluded that ANP homeostasis is altered in patients with CHF and that this hormone may be of importance in the pathophysiology of CHF.

Atrial Natriuretic Factor↗
PubMed1986

Central haemodynamics, baroreceptor sensitivity and alpha 1-adrenoceptor-mediated vascular reactivity during weight-stable sodium restriction in obese men with hypertension.

Ten obese men (20-40% overweight) with previously untreated arterial hypertension (WHO stages I and II) were examined before and during sodium-restricted isocaloric diets. The mean (+/- s.d.) daily sodium excretion was reduced from 199 +/- 65 to +/- 25 mmol/24 h. Intra-arterial blood pressure (BP), cardiac output (CO), plasma volume, circulating and urinary noradrenaline (NA), plasma renin activity (PRA) and urinary aldosterone were measured. Vascular reactivity was assessed with intravenous bolus injections of 50, 100 and 200 micrograms phenylephrine, and baroreflex sensitivity was assessed with the R-R interval response to pressure elevations on electrocardiogram. Significant reductions in systolic BP from 163 +/- 18 to 147 +/- 17 mmHg and in diastolic BP from 97 +/- 7 to 88 +/- 9 mmHg occurred during salt restriction. Blood pressure reductions were correlated with changes of urinary sodium excretion (r = 0.71; P less than 0.05). No significant changes in CO, heart rate (HR) or stroke volume (SV) were observed; therefore, BP reduction was secondary to the fall in total peripheral resistance (TPR) from 21.8 +/- 4.1 to 19.0 +/- 4.1 units (P = 0.05). Plasma volume, as well as total blood volume, was not affected by the moderate sodium restriction, but PRA rose from 0.71 +/- 0.1 to 0.87 +/- 0.1 micrograms angiotensin 1/ml per h (P less than 0.05). Urinary aldosterone was increased from 32 +/- 12 to 54 +/- 9 nmol/24 h. No change in venous or arterial concentrations of NA or of urinary NA was observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

Acute and long-term antihypertensive effect of bopindolol once daily or once weekly.

Fourteen male patients, mean age 53 years (range 35-64), were included in an initial 3 months' double-blind crossover study, in which 1-2 mg bopindolol, a nonselective beta blocker with intrinsic sympathomimetic activity (ISA), was compared with 100-200 mg metoprolol regarding effects on blood pressure and heart rate. During the subsequent long-term therapy, eight patients were trained to measure home blood pressure, and in these patients bopindolol 1 mg daily was compared to 8 mg once weekly in a double-blind fashion for 3 weeks on each regimen. Bopindolol (mean dose 1.35 mg/day) caused a significant blood pressure reduction, 26/15 mm Hg, as did metoprolol, 24/3 mm Hg (mean dose 144 mg/day) (NS). Supine and standing heart rates were reduced during both bopindolol and metoprolol treatment. During long-term therapy with bopindolol satisfactory blood pressure control was achieved for 1 year in 11 patients. Heart rate was significantly reduced after 2-3 months' treatment and during the entire 1-year follow-up. Few and well-tolerated side effects were reported. During treatment with bopindolol 8 mg once weekly, the blood pressure control was maintained satisfactorily over the week and no significant differences were observed in comparison with daily administration (1 mg) of the drug.

Adrenergic beta-Antagonists↗
PubMed1986

Increase in plasma atrial natriuretic peptides during acute volume expansion in hypertensive man.

A new hormonal system originating from cardiac atria has recently been discovered. These peptide hormones have important functions in the regulation of blood volume and fluid homeostasis. We have measured plasma concentrations of atrial natriuretic peptides (ANP) in two patients during acute volume expansion. ANP concentrations increased in relation to an increase in right atrial pressure, and significant diuresis/natriuresis was observed. We conclude that hormonal as well as neuronal mechanisms are activated by acute volume loading in man.

Atenolol↗
PubMed1986

Calcium channel blockers: spectrum of side effects and drug interactions.

Calcium antagonists are a chemically heterogenous group of agents with potent cardiovascular effects which are beneficial in the treatment of angina pectoris, arterial hypertension and cardiac arrhythmias. The main side effects for the group are dose-dependent and the result of the main action or actions of the calcium antagonists, i.e. vasodilatation, negative inotropic effects and antiarrhythmic effects. Pronounced hypotension is reported for the main calcium antagonist drugs; verapamil, diltiazem and nifedipine. While conduction disturbances and bradycardia are seen more often after verapamil and diltiazem, tachycardia, headache and flush are more frequent after nifedipine. Constipation is relatively frequent after verapamil while nifedipine is reported to induce diarrhea in som patients. Idiosyncratic side effects are rare but have been reported from the skin, mouth, musculoskeletal system, the liver and the central nervous system. These side effects include urticarial rashes, gingival hyperplasia, arthralgia, hepathotoxicity and transistory mental confusion or akathisia. Verapamil, diltiazem and possibly also nifedipine have been reported to increase serum digoxin concentrations but the clinical relevance of these drug interactions are not clear. Furthermore, verapamil and diltiazem may potentiate the effects of beta-adrenergic blocking drugs and verapamil may also potentiate the effects of neuromuscular blocking drugs. It is concluded that side effects after calcium antagonist drugs are mostly trivial and transient although they may sometimes be relatively common. Clinically relevant drug interactions are few. Judged from the point of efficacy and safety, calcium antagonists will have a major place in the future pharmacotherapy of several cardiovascular disorders.

Adrenergic beta-Antagonists↗
PubMed1986

Developmental variations in CSF monoamine metabolites during childhood.

Cerebrospinal (CSF) fluid content of the stable metabolites homovanillic acid, 3-methoxy-4-hydroxyphenyl glycol and 5-hydroxyindoleacetic acid were measured in 19 children without neurological disease known to alter CSF monoamine metabolites. The CSF levels of all three metabolites were found to be up 6 times higher in early infancy compared to the values during adolescence. The levels decreased in a logarithmic fashion, and adult values (approx. 25-50 ng/ml) were reached at 3-5 years of age. Two different interpretations of the findings are discussed: (1) a higher release or turnover of central serotonin and catecholamine metabolites during early postnatal age, or (2) lower clearance of the stable acid metabolites from CSF during infancy due to relatively immature active transport mechanisms.

Adolescent↗
PubMed1986

Does alcohol absorb to activated charcoal?

Activated charcoal seldom is used in pure-alcohol poisoning since it is absorbed rapidly from the gut. Furthermore in early reports activated charcoal was found to adsorb alcohol poorly. However, in 1981 North et al. [North, D. S., Thompson, J. D. & Peterson, C. D. (1981). Am. J. Hosp. Pharm., 38, 864-866] demonstrated in dogs that charcoal given at the same time as alcohol can reduce the blood alcohol concentration significantly. To study whether charcoal is of value in a clinical situation, a randomized cross-over study in two phases was conducted. Each person drank 88 g of alcohol and 30 min after either 20 g of activated charcoal was taken or the same volume of water was drunk. There were no significant differences in plasma alcohol concentrations with or without charcoal.

Adsorption↗