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Biomedical subjects

L Wiklund

Publications and source records attributed to L Wiklund.

At least 199 records · Page 11Linked to original sources
PubMed1978

Renal haemodynamics before and after splanchnic block in patients with hypertension.

In eighteen patients with hypertension of presumed renal origin the haemodynamics of the kidney were studied by arterial pressure recording, blood flow measurement and selective arteriography before and after a splanchnic block. The material was divided into kidneys with and kidneys without arterial stenosis. In these patients with hypertension a positive correlation was found between mean arterial pressure and renal vascular resistance both before and after the splanchnic block. In patients with renal arterial stenosis the change in relative renal vascular resistance was negatively correlated to the initial resistance, implying that in kidneys with a high initial vascular resistance the resistance decreased to a relatively greater extent than in kidneys with a low initial resistance. At high blood pressures ischaemic areas in the kidney were found. The volume of these areas is dependent upon sympathetic tone, such that a high sympathetic tone results in ischaemia of a larger volume of the kidney. This applies both to kidneys with and to those without arterial stenosis. The results of this investigation thus support the assumption that in the presence of hypertension a kidney is under the control of a sympathetic tone that may form a part of the pathogenetic process in hypertension.

Adult↗
PubMed1978

The circulatory effects of intravenously administered ephedrine during epidural blockade.

The changes in central circulation following a small dose of intravenously administered ephedrine were studied in middle-aged and elderly patients during high epidural blockade with bupivacaine 0.5% with adrenaline, etidocaine 1% with adrenaline, and etidocaine 1% plain. Itravenously injected ephedrine restored the mean, systolic and diastolic arterial blood pressures to the preanalgesic value independent of the degree of hypotension, and was not followed by marked hypertension in any case. Although the heart rate did not change, the cardiostimulatory effects were more pronounced than after subcutaneous premedication, resulting in increased stroke volume and cardiac output in all groups. Peripheral vascular resistance increased to the preanalgesic value in the groups receiving bupivacaine adrenaline and etidocaine plain. In the etidocaine adrenaline group, peripheral vascular resistance was little changed, as the cardiostimulatory effects were more pronounced than in the other groups.

Aged↗
PubMed1977

The indolaminergic innervation of the inferior olive. 2. Relation to harmaline induced tremor.

The possible involvement of serotoninergic mechanisms in the induction of harmaline generated tremor in the inferior olive has been investigated electrophysiologically in the cat and rat. Mass recordings of Purkinje cell activity in the cat showed that harmaline induces strong, synchronous and rhythmic activity in those parts of the climbing fibre system originating in the caudal part of the medial accessory olive and the caudolateral parts of the dorsal accessory nucleus. These are the areas of the cat olive shown to receive a dense serotoninergic innervation. In the rat, the selective removal of the serotoninergic innervation--produced by an intraventricular injection of 5,6-dihydroxytryptamine, or 5,7-dihydroxytryptamine in combination with desipramine--caused a significant attenuation of both the tremor and the climbing fibre activity induced by an intravenous harmaline injection. In the 5,6-dihydroxytryptamine-treated animals the reappearance of the harmaline tremor seemed to parallel the regrowth of new serotoninergic axon sprouts in the inferior olive. On the basis of the present results it is proposed that the serotoninergic afferents to the accessory olivary nuclei are of critical importance for the tremor induction of harmaline in the inferior olive. It is suggested that harmaline, rather than acting directly on the olivary neurones, exerts its effect through an interference with a serotoninergic (possibly inhibitory) innervation of these cells.

5,6-Dihydroxytryptamine↗
PubMed1977

Human hepatic blood flow and its relation to systemic circulation during intravenous infusion of lidocaine.

Twelve healthy young volunteers were studied before and during intravenous administration of lidocaine at a dose rate of 2 or 4 mg/min. Five additional volunteers, who did not receive lidocaine solution but were given the same amount of physiological saline, were studied in the same manner. Heart rate, cardiac output, mean arterial blood pressure, mean right atrial blood pressure, estimated hepatic blood flow and plasma concentration of lidocaine were measured repeatedly. The results showed an increase in heart rate, cardiac output and mean arterial blood pressure, the latter two variables in relation to the plasma concentration of lidocaine. The estimated hepatic blood flow increased, partly as a result of the reduction of splanchnic vascular resistance and partly due to the stimulation of cardiac output. The decrease in splanchnic vascular resistance was proportional to the plasma concentration of lidocaine.

Blood Pressure↗
PubMed1977

Human hepatic blood flow and its relation to systemic circulation during intravenous infusion of bupivacaine or etidocaine.

Fifteen healthy young volunteers were studied before and during an intravenous infusion of a local anaesthetic agent. Seven received bupivacaine and eight etidocaine in a dose rate of 2 mg/min over a period of 150 min. Variables of the central systemic circulation and also the hepatic blood flow were measured repeatedly. The circulatory alterations during administration of the two drugs were compared. Comparisons with previous results concerning lidocaine and a placebo were also made. It was found that bupivacaine increased the heart rate, mean arterial blood pressure and cardiac output significantly more than did etidocaine in an equal plasma concentration. Lidocaine was intermediate between bupivacaine and etidocaine. In contrast, these three drugs had the same decreasing effect upon the splanchnic vascular resistance, which caused an almost identical increase in the estimated hepatic blood flow. The calculated vascular resistance in the systemic circulation, excluding the splanchnic, was unchanged during the infusion of etidocaine, while it decreased during the infusion of bupivacaine. Most of this discrepancy was due to the different plasma concentrations of the drugs.

Acetanilides↗
PubMed1977

Influence of intravenously administered ephedrine on splanchnic haemodynamics and clearance of lidocaine.

The effects of a 20 mg i.v. bolus of ephedrine sulphate on haemodynamics and plasma lidocaine concentrations were evaluated in eight volunteer subjects receiving a constant i.v. infusion of lidocaine HC1 (2 or 4 mg-min-1). Injection of ephedrine caused a significant increase in mean arterial blood pressure, which preceded an elevation of heart rate by about 2 min. Cardiac output and hepatic blood flow, measured at 10 and 20 min after injection, were also increased significantly, while there was a decrease in total peripheral resistance and no change in splanchnic vascular resistance. There were no significant circulatory alterations over the same period in a control group of four subjects on receiving the lidocaine infusion. After ephedrine, the mean splanchnic extraction ratio of lidocaine fell from 0.76 to 0.66 at 10 min, then rose again to 0.71 at 20 min, and these changes were accompanied by a 9% increase in its splanchnic clearance. Extraction and clearance remained unchanged in the control group. The implications of these findings are considered in relation to the use of ephedrine to prevent or treat hypotension after peridural block with local anaesthetic agents.

Blood Pressure↗
PubMed1977

Splanchnic elimination and systemic toxicity of bupivacaine and etidocaine in man.

Fifteen healthy young volunteers were studied in connection with an intravenous infusion of a local anaesthetic agent. Seven received bupivacaine and eight etidocaine in a dose rate of 2 mg.min-1 over a period of 150 min. The hepatic blood flow and arterial-hepatic venous differences of the two drugs were measured. The estimated hepatic blood flow increased during the infusion of both drugs. While the splanchnic extraction ratio decreased during infusion of bupivacaine to 0.41 +/- 0.13, the same variable did not change (0.76 +/- 0.07) when etidocaine was infused. After 150 min infusion, the splanchnic clearance of bupivacaine and etidocaine was 0.76 +/- 0.27 and 1.32 +/- 0.21 1.min-1, respectively. Slight symptoms of central nervous toxicity were noted towards the end of the bupivacaine infusion, while no such symptoms appeared with etidocaine. A comparison between earlier published data on the blocking properties and the disposition pharmacokinetics of the two drugs shows that etidocaine is likely to confer a clinical advantage over bupivacaine as regards toxicity.

Acetanilides↗
PubMed1976

Influence of sympathetic nerve activity on renal haemodynamics and release of renin. A preliminary communication.

The role of the sympathetic nerve system is still unknown in different types of hypertension. The procedure used in the evaluation of suspect renovascular hypertension has been revised in such a way that renal blood flow, renal arterial blood pressure and plasma renin activity in renal vein could be determined prior to and after splanchnic blockade. A new divice-videovolumeter-has been used to investigate the blood flow. Some preliminary data are given.

Adult↗
PubMed1976

Non-occlusive enteric gangrene associated with severe upper gastrointestinal bleeding.

Six cases of non-occlusive enteric gangrene in association with severe upper gastro-intestinal haemorrhage are described, the incidence of which corresponds to approximately one per cent of the patients with serious gastric bleedings. A brief discussion of the pathophysiology of ischaemic gut lesions is given. In order to reduce the incidence of this disease rapid and adequate treatment of all massive gastro-intestinal bleedings is emphasized. Patients with unexplained abdominal pain in association with haemorrhagic shock should especially be regarded as being at risk of developing the enteric gangrene.

Adult↗