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Biomedical subjects

H Vik-Mo

Publications and source records attributed to H Vik-Mo.

At least 91 records · Page 5Linked to original sources
PubMed1982

Myocardial lipoproteins lipase activity during acute myocardial ischemia in dogs.

The influence of an acute myocardial ischemia on lipoprotein lipase (LPL) activity in the myocardium was studied in open chest dogs. Myocardial ischemia was induced by occlusion of a branch of left descending coronary artery and biopsies were taken from non-ischemic and ischemic myocardium. After 60 min of myocardial ischemia a significantly lower LPL activity was found in full wall biopsies of ischemic than of non-ischemic left ventricular myocardium. The ischemia-induced reduction in LPL activity was most pronounced in the endocardial half of the myocardium. Reduction of LPL activity in the ischemic zone might contribute to limitation of the ischemic injury through reduction of FFA extraction from plasma triglycerides.

Animals↗
PubMed1982

Can left main or proximal left anterior descending coronary artery disease be assessed by non-invasive means?

One hundred consecutive patients with angina pectoris referred for coronary arteriography were studied prospectively for non-invasive assessment of left main (LMCA) or proximal left anterior descending coronary artery (proximal LAD) disease. Evaluation of echocardiographic interventricular septal motion, history and exercise test response could not identify the patients with these specific lesions. It is concluded that LMCA and proximal LAD disease still remain largely unpredictable by non-invasive means.

Adult↗
PubMed1982

Effect of hyaluronidase on substrate exchange and blood flow in the ischaemic myocardium of the dog.

The mechanism for reduced myocardial ischaemic injury by hyaluronidase was studied in open chest anaesthetized dogs. Repeated coronary artery occlusions were performed and the effect of hyaluronidase (225 NF units per kg) was studied during infusion of noradrenaline 0.125 mg/kg . min. Ischaemic injury was measured as the sum of ST-segment elevations (sigma ST) at 10-15 sites. Regional myocardial blood flow was determined by tracer microspheres. Blood for metabolic studies was sampled from a local coronary vein draining ischaemic tissue and from the coronary sinus draining predominantly non-ischaemic tissue. Hyaluronidase reduced sigma ST and increased subepicardial and transmural blood flow in ischaemic myocardium, but flow was not significantly changed in the ischaemic subendocardium or in non-ischaemic myocardium. Hyaluronidase had no significant effect on arterio-local venous differences of oxygen, glucose, lactate or free fatty acids across the ischaemic myocardium. In conclusion, reduction of myocardial ischaemic injury by hyaluronidase can be explained by increased collateral blood flow and not by an effect on fluxes of substrates across the ischaemic myocardium.

Animals↗
PubMed1982

Role of the Frank-Starling mechanism during maximal semisupine exercise after oral atenolol.

Reproducible left ventricular dimensions were found by M-mode echocardiography in eight healthy men in the semisupine position during two maximal bicycle exercise tests, performed with four hours interval. Left ventricular end-diastolic dimension did not increase during maximal exercise, while fractional shortening increased by a decrease in end-systolic dimension. Twelve men studied by the same procedure were given 100 mg atenolol orally just after the first test which conspicuously reduced their heart rate response to exercise. End-diastolic dimension increased significantly from rest to peak exercise after the administration of atenolol in contrast to that before beta blockade, and fractional shortening at maximal exercise increased compared with the preceding control test. We conclude that atenolol changes the left ventricular response to maximal semisupine exercise in normal man, with dilatation and a concomitant increase in systolic myocardial shortening. This suggests that atenolol during maximal exercise reveals the part played by the Frank-Starling mechanism in cardiac reserve. In addition to that mechanism, the increased ventricular emptying is probably also the result of reduced afterload after administration of atenolol.

Adult↗
PubMed1981

Influence of free fatty acids on myocardial oxygen consumption and ischemic injury.

Myocardial oxygen consumption (MVO2) is influenced by the substrate supply to the heart. Utilization of free fatty acids increases MVO2, and catecholamines sensitize the heart to the oxygen-wasting effect of free fatty acids. Alteration of myocardial metabolism from mainly free fatty acid to carbohydrate oxidation reduces the extent of myocardial ischemic injury. Within the ischemic myocardium, lipolysis is stimulated with breakdown of endogenous triglycerides to fatty free acids and glycerol. Antilipolytic agents seem to have a combined effect on myocardial metabolism partly through inhibition of lipolysis in adipose tissue with reduction of free fatty acid mobilization to plasma, and partly through a local inhibition of lipolysis in the ischemic myocardium. In patients with high sympathoadrenal activity, for example, patients with acute myocardial ischemia in unstable ischemic heart disease, elevation of free fatty acids might effect a critical increase in both myocardial oxygen requirement and infarct size.

Adipose Tissue↗
PubMed1981

Adipose tissue perfusion and fatty acid release in exercising rats.

Arterial concentrations of free fatty acids (FFA), glycerol and lactate were measured in male Wistar rats before, during and after 30 minutes exercise on a treadmill. The arterial concentration of glycerol increased 120% and lactate 340% during exercise, but fell immediately upon its termination. The arterial concentration of FFA increased only 20% during the exercise, but was followed by a sharp rise in the recovery period. Maximum FFA concentration was found after 6 minutes of recovery, reaching 70% above the preexercise level, whereafter plasma FFA fell. Using radioactivity labelled microspheres it was found that the fraction of cardiac output reaching adipose tissue after 10 min of exercise was reduced by 30-90% in relation to the resting value. After 3 min recovery, however, the fractional distribution to the same tissue was in average 300% above the value measured 3 min before termination of exercise. It is concluded that the increase in plasma FFA observed during the early recovery period is caused by increased FFA release from adipose tissue, as a consequence of increased adipose tissue perfusion in the recovery period.

Adipose Tissue↗
PubMed1981

Acute effects of the coronary vasodilator carbocromen on myocardial oxygen consumption, substrate uptake and mechanical performance in intact dogs.

The effects of carbocromen on myocardial substrate uptake, myocardial oxygen consumption (MVO2), and the mechanical activity of the heart was studied in eight intact, anaesthetized dogs. Carbocromen was given i.v. as an injection of 2 mg/kg body weight, and measurements performed in the basal condition and during isoprenaline infusion. Carbocromen increased myocardial blood flow and reduced coronary vascular resistance 15 and 30 min after administration, whereas these values returned to normal after 60 min. The myocardial performance, net myocardial uptake of free fatty acids (FFA), glucose and lactate and MVO2 were not changed by carbocromen. A second isoprenaline infusion 90 min following carbocromen administration induced changes in myocardial performance, net substrate uptake and oxygen consumption not significantly different from isoprenaline infusion prior to carbocromen administration. The antianginal effects by carbocromen observed in clinical studies are more likely to be mediated through its known coronary vasodilator effect than any influence on myocardial metabolism.

Animals↗
PubMed1981

Acute effects of p-chlorophenoxyisobutyrate on myocardial metabolism and performance in dogs.

Acute effects of the antilipolytic agent p-chlorophenoxyphenoxyisobutyrate (CPIB) on net myocardial uptake of free fatty acids (FFAu), myocardial oxygen consumption (MVO2), and mechanical activity of the heart were studied in seven intact, anesthetized dogs. CPIB was given i.v and studies performed under basal conditions and during isoprenaline-stimulated lipolysis. Under basal conditions CPIB did not influence FFAu, MVO2 or mechanical activity of the heart. During isoprenaline infusion CPIB reduced FFAu from 42.3 +/- 15.6 (mean +/- SEM) to 15.6 +/- 8.3 micromol/min . 100 g tissue (p less than 0.02) and MVO2 from 28.2 +/- 3.3 to 23.8 +/- 2.5 ml/min . 100 g (p less than 0.02). The reduction in MVO2 could not be explained by reduced mechanical activity of the heart. Most likely the mechanism for the reduction in MVO2 effected by CPIB during isoprenaline infusion was mediated by reduced myocardial FFA consumption.

Animals↗
PubMed1979

Pharmacokinetics of sulphadiazine, sulphamethoxazole and trimethoprim in patients with varying renal function.

The pharmacokinetics of tablets containing combinations of sulphadiazine (SDZ) and trimethoprim (TMP) (cotrimazine) and tablets with sulphamethoxazole (SMZ) and TMP (co-trimoxazole) were compared in patients with different renal functions. In normal renal function, SMZ is more similar to TMP than in renal impairment. In renal impairment although the serum half-life (t1/2) of both active and total SDZ remains similar to that of TMP, the t1/2 of total SMZ becomes several times higher than the t1/2 of TMP. The unchanged SMZ maintains approximately the same elimination velocity in reduced as in normal renal function. Consequently, for co-trimoxazole there is a buildup of SMZ metabolites which can only contribute to toxicity for co-trimoxazole, whereas the co-trimazine components have t1/2 values of the same order, also in renal dysfunction. The distribution volumes of SDZ, SMZ or TMP are the same regardless of renal function. However, the distribution volume of SDZ is closer to that of TMP, i.e. higher than the SMZ values. More active SDZ is excreted in the urine than SMZ both in normal and in reduced renal function. Thus co-trimazine, in addition to having some advantages in the normal individual, is in many respects distinctly more suitable in patients with renal functional impairment. On the basis of the patients with renal functional impairment. On the basis of the pharmacokinetic properties, dosage schedules are suggested that will give approximately the same plasma levels regardless of renal function.

Drug Combinations↗
PubMed1979

Effect of myocardial ischaemia and antilipolytic agents on lipolysis and fatty acid metabolism in the in situ dog heart.

Myocardial metabolism was studied in open-chest dogs before and during induction of myocardial ischaemia by coronary artery occlusion. Blood was sampled from a local coronary vein draining ischaemic tissue and from coronary sinus draining predominantly nonischaemic tissue. In the basal state, induction of myocardial ischaemia stimulated myocardial lipolysis as shown by release of glycerol from the ischaemic zone. During isoprenaline infusion, free fatty acids (FFA) extraction across the ischaemic myocardium was substantially increased, but no glycerol release occurred. Pretreatment with nicotinic acid or sodium salicylate markedly depressed FFA extraction across ischaemic myocardium, both during basal and isoprenaline stimulated lipolysis and nicotinic acid most likely inhibited lipolysis in the ischaemic zone. Thus, reduced severity of acute ischaemic injury by antilipolytic treatment might be due to a combination of inhibited myocardial lipolysis and reduced FFA extraction.

Animals↗
PubMed1979

Influence of high plasma concentrations of free-fatty acids on heart rhythm in healthy fasting men.

Ten healthy male student in regular sinus rhythm fasted for 66 hours. Their overnight fasting plasma concentration of free fatty acids (FFA) was 455 +/- 104 micro mol/1 (mean +/- S.E.M., n=7), the reference value of our laboratory, measured in another normal population of young men, being 344 +/- 28 micro mol/1 (n=10). After 42 and 66 hours of fasting, the plasma concentration of FFA rose to 1198 +/- 181 (p less than 0.01, n=10) and 1471 +/- 89 micro mol/1 (p less than 0.001, n=10), respectively. During the last 24 hours of fasting, the heart rate rhythm was monitored continuously by means of a Holter recorder and computer. No arrhythmias were observed, indicating that elevated plasma concentrations of FFA, exceeding those reported in patients with acute myocardial infarction, are well tolerated by the healthy human myocardium.

Adult↗
PubMed1978

Cardiac effects of thoracic epidural analgesia before and during acute coronary artery occlusion in open-chest dogs.

The effects of thoracic epidural analgesia (TEA) on myocardial performance and metabolism and on the severity of an acute myocardial ischaemia, were studied in eight anesthetized open-chest dogs. TEA reduced mean arterial blood pressure (AP) by 26%, heart rate (HR) by 20%, left ventricular dP/dt by 37%, and myocardial oxygen consumption by 27%. Although arterial concentrations of free fatty acids, glucose and lactate were unchanged, their myocardial uptake was reduced in proportion to the reduction in mechanical activity of the heart. Acute ischaemic injury was estimated from epicardial ECG recordings 10 min after occlusion of a branch of the left anterior descending coronary artery. In seven of eight dogs TEA caused a substantial reduction in the severity of the acute myocardial ischaemic injury. In the eight dogs investigated, the sum of ST segment elevations in epicardial ECG recordings was reduced from 34.0 +/- 3.4 to 23.3 +/- 2.8 mV (mean +/- SEM, P less than 0.01). After restoration of AP and HR to control values with phenylephrine and atrial pacing, the favourable effect of TEA on myocardial ischaemic injury was abolished. It is concluded that TEA effected a reduction in the severity of myocardial ischaemia in open-chest dogs, mainly through reduction of myocardial mechanical activity with consequent reduction of myocardial metabolism.

Anesthesia, Epidural↗
PubMed1978

Platelet accumulation in the myocardium during acute nonthrombotic coronary artery occlusion in dogs.

The distribution of labelled autologous platelets in the myocardium was studied in open-chest dogs following a nonthrombotic coronary artery occlusion. A significant accumulation of platelets occurred in the ischaemic and borderline ischaemic myocardium both 15 and 150 min after coronary artery occlusion, most pronounced after 150 min. The small platelet accumulation after 15-min ischaemia might be due to stasis of blood since a similar increase in labelled erythrocytes in that area was observed. The platelet trapping after 150 min most likely represents platelet aggregates. In spite of the marked increase in platelet trapping, the myocardial blood flow in the ischaemic area increased significantly from 15 to 150 min of myocardial ischaemia. It is concluded that the increased platelet trapping in the first hours following a nonthrombotic coronary artery occlusion was insufficient to impair coronary circulation.

Acute Disease↗
PubMed1978

Effects of sodium salicylate on plasma insulin concentration and fatty acid turnover in dogs.

The effects of intravenous sodium salicylate administration on plasma concentrations of insulin, free fatty acids (FFA) and glucose were studied in intact, anaesthetized dogs both during basal and isoprenaline stimulated lipolysis. In both situations sodium salicylate reduced the plasma concentrations of insulin. The reduction was associated with decreased plasma FFA concentrations and FFA turnover rate, while plasma glucose concentrations remained unaltered. The reduced plasma insulin concentrations effected by sodium salicylate is most likely secondary to the concomitant fall in plasma FFA concentrations due to inhibition of FFA mobilization from adipose tissue.

Adipose Tissue↗
PubMed1978

Mechanisms for inhibition of free fatty acid mobilization by nicotinic acid and sodium salicylate in canine subcutaneous adipose tissue in situ.

Mechanisms for reduced free fatty acids (FFA) mobilization effected by nicotinic acid (NA) and sodium salicylate (SS) were studied in canine adipose tissue in situ. Both drugs inhibited adipose tissue lipolysis as evidenced by reduced release of glycerol. In addition, although the total amount of FFA re-esterified was not significantly changed, the amount of FFA re-esterified relative to the amount of FFA liberated intracellularly was significantly increased by both drugs. These effects were most pronounced during isoprenaline-stimulated lipolysis. Thus NA and SS reduced mobilization of FFA from canine adipose tissue through a combined effect on re-esterification and lipolysis.

Adipose Tissue↗
PubMed1978

Disseminated intravascular coagulation in patients with meningococcal infection: laboratory diagnosis and prognostic factors.

In 36 patients with meningococcal infection a close association between the laboratory evidence of disseminated intravascular coagulation (DIC) and unfavourable prognostic factors was established. Patients with platelet count lessthan 100000/microliter, Normotest lessthan 50% and plasma fibrinogen concentration less than 100 mg/dl had a serious prognosis. No significant differences could be extablished between patients with infection from serogroup A and B meningococci for either laboratory evidence of DIC or prognostic factors.

Adolescent↗