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Biomedical subjects

P Manhem

Publications and source records attributed to P Manhem.

43 records · Page 3Linked to original sources
PubMed1981

Plasma cyclic nucleotides and plasma catecholamines before and after prolonged treatment with clonidine in hypertensive patients.

The effect of standing and physical exercise and catecholamines and cyclic nucleotides in plasma was measured in 8 patients with essential hypertension under standardized conditions before and after prolonged treatment with clonidine. Before clonidine medication noradrenaline, adrenaline and cyclic AMP (cAMP) increased in response to standing and bicycling for 20 min. No significant correlation was found between their absolute levels nor was the increase in cAMP following exercise correlated to the increase in noradrenaline. Standing and physical exercise were without effect on cyclic GMP (cGMP). Clonidine reduced the plasma noradrenaline concentration in supine position and the noradrenaline and the adrenaline response to standing and exercise. Plasma cAMP was uneffected by clonidine under basal conditions but the response to exercise was slightly reduced initially. During clonidine there was a positive correlation between the plasma levels of cAMP and noradrenaline following work. Clonidine produced an increase in plasma cGMP in supine position, immediately prior to bicycling and after 5 min of exercise.

Adult↗
PubMed1978

Plasma catecholamine levels in the coronary sinus, the left renal vein and peripheral vessels in healthy males at rest and during exercise.

Noradrenaline and adrenaline were determined in blood samples from the brachial vein, the brachial artery, the left renal vein and the femoral vein in 6 healthy males (aged 23-35 y). In 3 of the subjects catecholamines were determined also in blood from the coronary sinus. All samples were taken simultaneously in supine postion after 30 min of rest and then in connection with exercise in supine position using a bicycle ergometer, firstly with a work load of 50 W for 9 min and secondly with a work load of 150 W for the same period of time. Under resting conditions the catecholamine levels were about the same at all locations, the mean for noradrenaline being 1.59 nmol/1 with a range of 1.30-2.11 nmol/1 and for adrenaline 0.46 nmol/1 and 0.23-0.65 nmol/1, respectively. At 50 W the noradrenaline concentration increased significantly in the brachial artery, the left renal vein and the femoral vein, whereas adrenaline increased significantly only in the femoral vein. At 150 W the noradrenaline content increased markedly in all samples, especially in the left renal vein (mean increase 13.02 nmol/1) and the coronary sinus (mean increase 13.06 nmol/1). Adrenaline concentration increased significantly in the brachial artery and the femoral vein. At 150 W the mean net output of noradrenaline as estimated from the calculated flows and actual AV-differences amounted to 2.25 nmol/min from the heart and to 0.36 nmol/min from the kidney.

Adult↗
PubMedDate not supplied

Alcohol withdrawal: effects of clonidine treatment on sympathetic activity, the renin-aldosterone system, and clinical symptoms.

Twenty male alcoholics with alcohol withdrawal syndrome were randomized to receive either oral clonidine (3-600 micrograms, six hourly) or oral chlormethiazole (500-1000 mg, six hourly) for 4 days. All subjects were also given oral carbamazepine (200 mg, 12 hourly) throughout the study. Nine subjects given clonidine and eight given chlormethiazole completed the study. Clonidine was as effective as chlormethiazole in suppressing the symptoms and signs of alcohol withdrawal. However, plasma catecholamines, blood pressure, and pulse rate fell more rapidly and to a greater extent during clonidine than following chlormethiazole, findings which could have therapeutic implications. It is suggested that activation of brain noradrenergic neurons constitutes a common denominator in the pathophysiology of several withdrawal syndromes.

Adult↗