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Biomedical subjects

O J Hartling

Publications and source records attributed to O J Hartling.

52 records · Page 3Linked to original sources
PubMed1983

Generation and elimination of angiotensins I and II in the kidney, liver and lung.

Inflow and outflow concentrations of angiotensins I (AI) and II (AII) from both kidneys, the liver and the lung were measured in 30 hypertensive patients, the majority having lateralization of the renin secretion. In the renin secreting kidney the data indicated a high generation rate of AI. In the contralateral kidney and splanchnic region both AI and AII were 'eliminated', and in the lungs the results confirmed previous evidence of converting enzyme activity.

Adolescent↗
PubMed1982

Haemodynamic and metabolic effects of diazoxide during rest and forearm exercise.

The immediate haemodynamic and metabolic effects of acute dose of diazoxide 300 mg i.v. were studied in six healthy subjects at rest and during dynamic forearm exercise. Control periods of rest, exercise and recovery were compared with corresponding periods after drug administration. Resting forearm blood flow was almost doubled after diazoxide, and during forearm exercise it increased by about 24%. Systolic blood pressure did not change significantly, but diastolic blood pressure was moderately decreased (5-10 mm Hg). The mean heart rate increased from 57 to 92 beats/min immediately after diazoxide administration and remained about 20% higher throughout the study. There was a sustained increase in arterial blood glucose of almost 1 mmol/l. The arterial concentration of free fatty acids increased transiently just after diazoxide and then returned to the pre-drug level. The arterial concentration of triglycerides after diazoxide was decreased by about 15% throughout the study. Arterial blood lactate remained unchanged. Forearm uptake of oxygen and glucose tended to increase during the exercise and recovery periods, whereas lactate release remained unchanged.

Adult↗
PubMed1982

Beta-adrenoceptor blockade and psychic stress in man. A comparison of the acute effects of labetalol, metoprolol, pindolol and propranolol on plasma levels of adrenaline and noradrenaline.

1 A random double-blind study was performed in healthy volunteers. The immediate effects of three different beta-adrenoceptor blocking agents, metoprolol, pindolol and propranolol, on the plasma concentrations of adrenaline and noradrenaline were compared in a situation of pleasant psychic stimulation during a television-game of tennis. The immediate effects of labetalol in a group of patients with arterial hypertension were studied in a similar experimental situation. 2 During psychic stress the plasma concentration of noradrenaline rose significantly by 85% after placebo, by 95% after labetalol, by 63% after metoprolol and by 55% after propranolol. After pindolol the noradrenaline concentration remained unchanged. 3 During psychic stress the plasma concentration of adrenaline rose significantly by 135% after labetalol, by 110% after metoprolol and by 83% after propranolol. After pindolol and placebo the adrenaline concentration remained unchanged. 4 The present results are taken to indicate that the intrinsic sympathomimetic activity possessed by pindolol prevents the rise in plasma noradrenaline normally seen during psychic stress. It is suggested that beta-adrenoceptor blockers with strong intrinsic sympathomimetic effect reduce the release of catecholamines during psychic stress.

Adrenergic beta-Antagonists↗
PubMed1982

Stimulation of beta-adrenoceptors in the exercising human forearm.

In order to study the effects of local stimulation of beta-adrenoceptors on limb blood flow during exercise and on muscle metabolism, the non-selective beta-adrenoceptor agonist, isoprenaline, was infused intra-arterially into the forearm of six healthy, young subjects. Isoprenaline caused a marked increase in forearm blood flow not only at rest but also during dynamic forearm exercise. The forearm release of lactate increased considerably during drug infusion whereas glucose uptake decreased. The net uptake of free fatty acids during exercise decreased. There were no systemic effects of isoprenaline. These findings suggest that the resistance vessels are responsive to beta-adrenergic vasodilatation also during muscle exercise. The increase in blood flow through the exercising forearm may be secondary to an increased muscle metabolism. The increased lactate release from the exercising muscles indicates an increased muscle glycogen breakdown during beta-adrenoceptor stimulation.

Adult↗
PubMed1981

Systemic and forearm haemodynamic and metabolic effects of racemic propranolol or D-propranolol in healthy subjects.

1. The immediate haemodynamic and metabolic effects of intravenous administration of DL-propranolol and D-propranolol were studied in healthy male subjects at rest and during dynamic forearm exercise. The dose of DL-propranolol and of D-propranolol was 0.1 and 1.0 mg/kg body weight respectively. 2. DL-Propranolol reduced heart rate significantly at rest, during forearm exercise and post-exercise, whereas D-propranolol had a lesser effect on heart rate which was significant only at the end of the exercise period. Arterial blood pressure and forearm blood flow were unchanged after either drug. 3. Both drugs reduced the release of lactate from the exercising forearm. Forearm exchange of oxygen, glucose, free fatty acids and triglycerides remained unchanged. 4. The arterial blood glucose concentration increased after D-propranolol, but was unchanged after DL-propranolol. The arterial serum free fatty acid concentration decreased after DL-propranolol, but was not changed after D-propranolol. Arterial concentrations of lactate and triglycerides were not influenced by the drugs. 5. The chronotropic response to beta-adrenoceptor blockade appears to be stereoselective, suggesting specific blockade of beta-adrenoceptors. Metabolic responses to beta-adrenoceptor blockade are difficult to explain in terms of the known adrenoceptor system and may be due to non-specific actions of beta-adrenoceptor antagonists. An exception is inhibition of lipolysis, which is probably mediated via beta-adrenoceptors.

Adult↗
PubMed1981

Central and peripheral haemodynamic effects of prenalterol in patients with coronary heart disease.

The acute haemodynamic effects of prenalterol, a selective adrenergic beta-I-receptor agonist were studied in eight patients with coronary heart disease. Prenalterol was administered intravenously in four increasing doses to a cumulative dose of 5.6 mg. Fifteen minutes after the last dose of prenalterol two doses of the selective adrenergic beta-I-receptor antagonist metoprolol were administered intravenously to a cumulative dose of 17-5 mg. Ten minutes after each dose cardiac output, heart rate, arterial blood pressure, pulmonary artery pressure, systolic time intervals and forearm blood flow were determined. Haemodynamic effects of prenalterol: cardiac index and heart rate increased maximally by 38% and 39% respectively. Stroke index was increased by 6-9% after the first and second dose. Mean blood pressure was increased by 9.8 mmHg. Total peripheral resistance index was reduced by 19%. The mean pulmonary artery pressure decreased by 3.8 mmHg and pulmonary resistance index was reduced by 48%. Systolic time intervals were all reduced significantly after the second dose, which reflected the positive inotropic effects of prenalterol. Forearm blood flow increased by 29% and forearm vascular resistance was decreased by 20%. Haemodynamic effects of metoprolol: the haemodynamic changes induced by prenalterol were stepwise counteracted by metoprolol. After the second dose all the haemodynamic variables had returned to the control levels. It is concluded that prenalterol possesses a considerable positive inotropic as well as positive chronotropic effect on the myocardium. Both the chronotropic and inotropic effect of prenalterol was counteracted by metoprolol.

Blood Pressure↗
PubMed1980

Immediate haemodynamic effects of prenalterol, a new adrenergic beta-1-receptor agonist, in healthy volunteers.

The acute haemodynamic effects of prenalterol, a selective adrenergic beta-1-receptor agonist, were studied in eight healthy male volunteers. Prenalterol was administered i.v. in five increasing doses to a cumulative dose of 5.55 mg. After the last dose of prenalterol, three doses of the selective adrenergic beta-1-receptor antagonist metoprolol were administered i.v. to a cumulative dose of 17.5 mg. After each dose, cardiac output (CO), stroke volume (SV), blood pressure (BP), heart rate (HR), systolic time intervals (STI) and forearm blood flow (FBF) were determined. Prenalterol had the following effects: CO was significantly increased by 21.0% after the fourth dose, but the fifth dose did not further change CO. SV was unchanged after the first four doses, but after the fifth dose a significant decrease in SV of 7.0% was seen. Mean BP was increased significantly by 7.7%, but diastolic BP remained unchanged. HR was increased by 28.4%. Total peripheral resistance was reduced by 8.8%. STI were reduced significantly after the second dose, which indicates that prenalterol has a positive inotropic action. FBF was increased significantly after the fourth dose. After the third dose of metoprolol, the CO, SV, means BP, HR, STI and FBF had returned to their control values. It is concluded that prenalterol has positive inotropic and chronotropic effects on the myocardium, and that metoprolol is a specific antidote.

Adolescent↗
PubMed1980

Haemodynamic and metabolic effects of combined adrenergic alpha- and beta-receptor blockade with labetalol in the exercising human forearm.

At rest supine acute intravenous administration of the combined adrenergic alpha- and beta-receptor blocking compound labetalol (1 mg/kg body weight) to young, healthy, male subjects, produced a clear-cut fall in arterial blood pressure. During dynamic forearm exercise, forearm blood flow decreased by 17.2%, and calculated vascular resistance increased by 11.3% after labetalol. Forearm oxygen uptake decreased (14.6%), suggesting an increased mechanical efficiency. Lactate release from the exercising forearm decreased (17.6%), probably because of the beta-receptor blockade. Forearm uptake of glucose and free fatty acids remained unchanged. Arterial blood glucose concentration attained a higher level after labetalol. Arterial plasma concentration of FFA was reduced during exercise and post-exercise probably because beta-receptor mediated lipolysis was antagonized.

Adult↗
PubMed1980

Immediate haemodynamic and metabolic effects of intravenous labetalol in the exercising forearm.

Dynamic forearm exercise was performed in healthy subjects before and after intravenous labetalol, 1 mg/kg body weight. Labetalol produced a sustained fall in arterial blood pressure. Forearm blood flow decreased by 17.2% partly due to the reduced driving pressure and partly due to an increased vascular resistance. Forearm oxygen uptake decreased by 14.6%, suggesting an increased mechanical efficiency. Lactate release from the exercising forearm decreased by 17.6%. Forearm uptake of glucose and free fatty acids remained unchanged.

Blood Pressure↗
PubMed1980

Sequential haemodynamic effects of labetalol at rest and during exercise in essential hypertension.

The haemodynamic effects of labetalol were studied in patients with essential hypertension after acute and long-term administration. In the acute study 50 mg of labetalol was given i.v. to 10 patients. Eight of them were re-examined after three to four months of oral treatment with labetalol 300 mg t.i.d. Measurements were made at supine rest, after five minutes in the upright position, and after five minutes' supine bicycle exercise at 50 and 100 watt work loads. In the acute study cardiac output was unchanged except at the work load of 100 watt when it decreased 18%. The mean blood pressure decreased under all conditions, 11.6 mm Hg at supine rest, 22.3 mm Hg in the upright position and 15.9 mm Hg and 16.9 mm Hg at the two work loads. Heart rate was unchanged at supine rest, and reduced by 10% in the other situations. Total peripheral resistance was reduced significantly at rest in the supine and upright positions, but not during exercise. Pulmonary artery pressure was unchanged. In the long-term study cardiac output was unchanged except of the heavy work load when it decreased 11%. Mean blood pressure was reduced significantly by 14.6 mm Hg at supine rest, 16.8 mm Hg in the upright position and by 13.9 mm Hg and 13.4 mm Hg, respectively, at the two work loads. Heart rate was reduced significantly in all conditions by 10-14%. Total peripheral resistance decreased significantly at rest, but not during exercise, and pulmonary artery pressure was unchanged.

Blood Pressure↗
PubMed1980

Immediate effects of labetalol on central, splanchnic-hepatic, and forearm haemodynamics during pleasant emotional stress in hypertensive patients.

The effects of intravenous administration of labetalol in a dose of 0.75 mg/kg body weight on central, splanchnic-hepatic and forearm haemodynamics were studied in 8 hypertensive patients resting in the supine position and during pleasant psychic stress induced by practice of a television-game of tennis. In the resting state labetalol caused immediate reduction of arterial blood pressures and of total vascular resistance, whereas heart rate, cardiac output and splanchnic-hepatic and forearm blood flow remained unchanged. After labetalol, the stress-induced increase in heart rate, cardiac output, estimated myocardial oxygen demand and forearm blood flow was significantly reduced, whereas total vascular resistance and splanchnic-hepatic vascular resistance remained unchanged. This is taken to indicate that the alpha-adrenoceptor blocking properties of labetalol may offer haemodynamic advantages as compared to the widely used non-selective beta-adrenoceptor blocking agents in the management of hypertension.

Ethanolamines↗