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Biomedical subjects

K Rasmussen

Publications and source records attributed to K Rasmussen.

At least 361 records · Page 20Linked to original sources

General (medium-chain) acyl-CoA dehydrogenase deficiency (non-ketotic dicarboxylic aciduria): quantitative urinary excretion pattern of 23 biologically significant organic acids in three cases.

Urinary analysis of the pattern of 23 organic acid metabolites derived from fatty acids in three patients with general (medium-chain) acyl-CoA dehydrogenase deficiency was performed. Although there exist quantitative differences in the excreted amounts of the different metabolites in the three patients the qualitative picture was the same. The excretion of adipic, suberic and sebacic acids was substantial, whereas that of dodecanedioic acid was within or just above control limit. The monounsaturated C6-C10-dicarboxylic acid excretion was only marginally or not increased. 5-OH-hexanoic acid and hexanoylglycine were excreted in excessive amounts, whereas 7-OH-octanoic acid, 9-OH-decanoic acid, octanoylglycine and decanoylglycine were excreted in limited amounts. The excreted amounts of 6-OH-hexanoic, 8-OH-octanoic and 10-OH-decanoic acids were not or only marginally elevated compared to controls. In one of the patients the excretion of ethylmalonic and methylsuccinic acids was enhanced, whereas the excretion of these two acids in the two other patients was comparable to that in controls. The urinary excretion of hexanoic, octanoic, decanoic and dodecanoic acids was just a little above the control limit, whereas the esterified hexanoic and octanoic acids were excreted in appreciable amounts. It is argued that the microsomal omega- and omega-1-oxidation systems are involved in the dicarboxylic and omega-1-OH-monocarboxylic acids formation at C10 and C12 level and that the C8-C6-dicarboxylic and omega-1-OH-monocarboxylic acids are formed from higher chained acids by beta-oxidation in both mitochondria and peroxisomes.

Acyl-CoA Dehydrogenase↗

Raphe neurons: firing rate correlates with size of drug response.

Significant negative correlations were obtained between the spontaneous discharge rate during waking and the neural response to systemic injections of either 5-MeODMT or LSD for serotonergic neurons in the dorsal raphe nucleus, nucleus centralis superior, and nucleus raphe pallidus of unanesthetized and unrestrained cats. These data are discussed in terms of an hypothesis which accounts for both the rate of spontaneous activity of serotonergic neurons and the magnitude of their response to serotonin agonist drugs in terms of autoreceptor density on individual neurons.

Animals↗

Beta-oxidation of C-6-C-10 fatty acids in rat liver homogenates measured by selected ion monitoring: effects of cyanide and clofibrate.

The beta-oxidation of C-6-C-10-fatty acids/acyl CoA/acylcarnitines in whole rat liver homogenates was determined by specific and simultaneous measurements of the C-6-C-10-fatty acids, i.e. hexanoic, octanoic and decanoic acids, in hydrolysed homogenates in relation to time in assays incubated with the above-mentioned substrates. Measurements were performed by a combined gas chromatographic mass spectrometric technique, i.e. selected ion monitoring. The rate of beta-oxidation of the C-6-C-10-fatty acids/acyl CoA/acylcarnitines were registered as the consumption rate of the added substrate. The conversion to the C-2-shortened beta-oxidation products was illustrated simultaneously. The rate of beta-oxidation of C-6-C-10-fatty acids was several times higher in homogenates from clofibrate-treated rats than in control rats, both in the presence and absence of 2.0 mmol l-1 cyanide. Cyanide caused a minor but significant decrease in the beta-oxidation rate in both control and clofibrate-treated rats. No differences were found between the beta-oxidation of decanoic acid and decanoyl CoA in homogenates from clofibrate-treated rats, whereas the degree of beta-oxidation of DL-decanoylcarnitine was halved compared with decanoic acid and decanoyl CoA.

Animals↗

Prazosin treatment of primary Raynaud's phenomenon.

In a double blind study, prazosin, a specific adrenergic alpha 1-receptor antagonist, or placebo were given to 15 females with primary Raynaud's phenomenon. At a low dose (1 mg twice daily) 5 out of 7 of the prazosin-treated patients reported a reduction of attacks induced by cold (p less than 0.05). This was not confirmed by a cold provocation test which showed no improvement at finger temperatures of 15 or 10 degrees C. The highest tolerated dose in the prazosin-treated patients varied from 2-8 mg daily, and the greatest number of side effects was recorded in this group (p less than 0.05). None of the patients experienced complete relief from cold-induced attacks. It was concluded either that Raynaud's phenomenon is not only caused by stimulation of alpha 1-receptors in digital arteries or the clinically achievable blockade was insufficient to prevent attacks.

Blood Pressure↗

Effects of prenalterol on cardiac performance and transmural myocardial perfusion in patients with chronic renal failure.

The acute haemodynamic effects of the beta-adrenoreceptor agonist, prenalterol, were studied in six patients with chronic end-stage renal failure. Prenalterol 0.8 mg, 1.6 mg, and 3.2 mg was administered i.v. as a bolus, and after the last dose the selective adrenergic beta-1-receptor antagonist metoprolol was administered i.v. in doses of 5 and 10 mg. The haemodynamic effects of the drugs were investigated using impedance cardiography and radionuclide angiocardiography. The main haemodynamic effects were a dose-related chronotropic effect, demonstrated by an increase in heart rate (26%; less than 0.05), and an inotropic effect, shown by an increase in stroke volume index (20%; p less than 0.05) and left ventricular ejection time (12%; p less than 0.05); the cardiac index was increased by 47% (p less than 0.05). Transmural myocardial perfusion (DPTI/SPTI ratio) was decreased by 22% (p less than 0.05) after prenalterol. It is concluded that prenalterol has positive inotropic and chronotropic effects in patients with chronic renal failure, that the improvement in left ventricular performance is at the expense of a decreased transmural myocardial perfusion, and that metoprolol is a specific antidote.

Aged↗

Multilevel disease of the conduction system.

We found that the incidence and distribution of conduction system disease simultaneously affecting several levels of the system had been incompletely described. We therefore analysed all patients in whom conduction disease had been diagnosed and a complete electrophysiological study of the conduction system had been made, during a defined period. Patients were classified as to the presence or absence of sinus node disease, and proximal and distal atrioventricular disease. Since our hospital serves a defined population and a large proportion of all patients with conduction disease seen during the period was included, the series probably is representative of conduction disease in general. Twenty-four of the 59 patients had defects at more than one of the three levels (41%). Fifty-five per cent of the patients with sinus node disease had some kind of atrioventricular disease, while 42% of the latter had evidence of sinus node failure. The patients with multilevel disease were characterized by more severe symptoms, higher age and a higher incidence of generalized heart disease than those with single-level disease. The observations fit the concept that conduction system disease in most patients is part of a diffuse disease process progressively involving various parts of the system.

Arrhythmias, Cardiac↗

Hereditary bilateral retinoblastoma, pinealoma and normal chromosomes. A case report.

We report a boy with bilateral, familial retinoblastoma recognized at the age of 3 months. At the age of 2 1/2 years the patient developed a tumour in the pineal region. Both tumours were successfully treated by radiation. The chromosomes were normal when examined by the prophase technique, in particular there was no deletion of band q14 of chromosome 13. We consider the simultaneous occurrence of retinoblastoma and pinealoma as more then a pure coincidence, probably a consequence of a generally increased susceptibility to cancer and of the histogenetic similarities of retina and pineal body.

Brain Neoplasms↗

Cardiovascular effects of secretin infusion in man.

Secretin infusion in man causes an increase in renal blood flow. The aim of the present study was to assess further the cardiovascular effects of the hormone. Secretin was infused at a rate of 2 CU/kg X h to patients with angina pectoris and normal left ventricular function. Cardiac output increased by an average of 20%, the stroke volume increased and the total systemic resistance decreased. Systemic arterial pressure, heart rate and pulmonary capillary wedge pressure were unaltered. The results are compatible with a combined inotropic and vasodilating effect of the hormone. It is concluded that secretin may have potential merits in the treatment of acute left ventricular failure.

Adult↗

Effect of hemodialysis on cardiac performance and transmural myocardial perfusion.

The effects of hemodialysis on cardiac performance and myocardial oxygen balance were evaluated by impedance cardiography in 16 patients with end-stage renal failure treated with regular hemodialysis. Cardiac symptoms and/or failure were present in 8 patients (group A) whereas 8 patients (group B) had no signs of heart dysfunction. The hemodialysis were carried out without ultrafiltration so that the body weight was the same before and after dialysis. The two groups did not differ significantly with regard to either biochemical values or hemodynamic parameters before dialysis. During dialysis mean cardiac output (CO) increased significantly 7.1 +/- 2.8 l/min to 9.1 +/- 3.6 l/min (P less than 0.01), mainly in patients group A, and was maximum after 90 min. The myocardial oxygen balance estimated from the supply/demand ratio (DPTI/SPTI) was significantly reduced after 20 min from 1.14 +/- 0.16 to 0.99 +/- 0.12 (P less than 0.01). After 60 min DPTI/SPTI decreased to its lowest value due to an excess of myocardial oxygen demand (SPTI) over myocardial oxygen supply (DPTI), signifying a transitory underperfusion of the subendocardium which occurred mainly in patients with cardiac failure (group A). Mean arterial blood pressure remained unchanged whereas mean heart rate increased significantly after 90 min and remained raised throughout the rest of dialysis (78.8 +/- 10.4 bpm to 87.1 +/- 12.6 bpm [P less than 0.01]). Total peripheral resistance (TPR) was decreased significantly after 5 min (P less than 0.01), but subsequent falls were not significant. Changes in the DPTI/SPTI ratio showed that the improvement in left ventricular performance was at the expense of myocardial oxygen balance, which caused a greater incidence of myocardial underperfusion, particularly in patients with cardiac failure.

Adult↗

Cyanide-insensitive and clofibrate enhanced beta-oxidation of dodecanedioic acid in rat liver. An indication of peroxisomal beta-oxidation of N-dicarboxylic acids.

The beta-oxidation rate of dodecanedioic acid in rat liver homogenates (600 X g supernatant fraction) was determined by simultaneous measurements of the C6-C12-dicarboxylic acids, i.e., adipic, suberic, sebacic and dodecanedioic acids, in relation to time in assays incubated with dodecanedioic acid. Measurements were performed by a combined gas chromatographic-mass spectrometric technique, i.e., selected ion-monitoring. The beta-oxidation rate was registered as the consumption rate of dodecanedioic acid and as the initial rise in the concentrations of C6-C10-dicarboxylic acids. The beta-oxidation rate of C8-C12-dicarboxylic acids was increased many times in homogenates from clofibrate-treated rats. Moreover, it was unexpectedly found that 2.0 mM cyanide was unable to inhibit the beta-oxidation rate of the dicarboxylic acids in vitro, but in fact caused a minor increase in the rate of beta-oxidation in homogenates from both normal and clofibrate-treated rats. It was concluded that the present results strongly indicate the existence of a peroxisomal beta-oxidation of dicarboxylic acids.

Animals↗