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Biomedical subjects

I Magnussen

Publications and source records attributed to I Magnussen.

30 records · Page 2Linked to original sources
PubMed1978

Somatostatin in the treatment of patients with extra-pyramidal disorders and patients with EEG abnormalities.

The growth hormone release inhibiting hormone acts probably both as a true hypophysiotropic hormone and as a neuroregulatory substance. Neurophysiological studies have shown that somatostatin is a CNS depressant. Somatostatin might therefore be of therapeutic significance in neurological diseases. Sixteen patients with different extrapyramidal disorders and seven patients with various EEG abnormalities were tested with 2-hour somatostatin infusions and control infusions with saline. Somatostatin did not induce any improvement or deterioration of symptoms, signs, or EEG abnormalities in any patient.

Adult↗
PubMed1978

Post-hypoxic intention myoclonus treated with 5-hydroxy-tryptophan and an extracerebral decarboxylase inhibitor.

Post-hypoxic intention myoclonus successfully treated by long-term administration of the combination of 5-hydroxytryptophan and carbidopa is described. Persistent euphoria and diarrhoea were essential side effects. Methysergide (12 mg/day) blocked the therapeutic effect, indicating a specific serotoninergic function of precursor loading with 5-hydroxytryptophan. Tryptophan (8 g/day) had no effect on the myoclonus suggesting a reduced tryptophan hydroxylase activity. Plasma concentrations of 5-hydroxytryptophan in the range of 10--30 micromoles per liter were obtained during maintenance therapy with 900 mg 5-hydroxytryptophan per day in combination with 150 mg carbidopa per day.

5-Hydroxytryptophan↗
PubMed1978

Pharmacokinetics of theophylline in ten elderly patients.

The two-compartment pharmacokinetics of theophylline in ten hospitalized elderly patients with apparently normal renal, hepatic and cardiopulmonary functions was investigated after intravenous administration of the drug. Nine patients suffered from slight hemiparesis and one from Parkinson's disease. Biological theophylline half-lives of 5.4--9.0 hours and plasma clearence values of 28--42 ml kg-1hr-1 were found. The apparent volumes of distribution during the beta-phase, Vdbeta, were 0.33--0.43 1 kg-1. It is concluded that a therapeutic concentration of about 10 microgram theophylline per ml serum could be established in the investigated group of elderly patients following an intravenous initial loading dose of 3.7 mg theophylline per kg followed by a continuous infusion of 0.35 mg per kg body weight per hour. In the therapeutic use of theophylline monitoring of the serum theophylline concentration is generally advised because of the elsewhere reported variability in the biological half-life of the compound.

Age Factors↗
PubMed1978

The effects of aromatic amino acid decarboxylase inhibitors on plasma concentrations of 5-hydroxytryptophan in man.

5-Hydroxytryptophan has been found to be beneficial when administered alone or in combination with extracerebral aromatic amino acid decarboxylase inhibitors for therapeutic purposes in various disorders in which myoclonus is prominent. In five subjects the effect of decarboxylase inhibitors on the accumulation and elimination of 5-hydroxytryptophan in plasma was studied. The plasma concentrations of 5-hydroxytryptophan were increased about ten fold by pretreatment with the decarboxylase inhibitors, carbidopa and benserazide. Half-lives of 2.2--3.0 hrs. were obtained following oral administration of a single dose of 5-hydroxytryptophan with or without pretreatment. In one subject the half-life of 5-hydroxytryptophan in plasma increased to 5.5 hrs. during long-term treatment with carbidopa.

5-Hydroxytryptophan↗
PubMed1978

Determination of 5-hydroxytryptophan in plasma by high-performance liquid chromatography and fluorometric detection after phthaldialdehyde reaction.

We describe the sensitive and precise determination 5-hydroxytryptophan in plasma from patients treated with this compound. The method is based on solvent extraction of plasma, high-performance liquid chromatography and continuous fluorometric detection after reaction with phthaldialdehyde in strong acid. The combined time for chromatography and reaction is 25 min. The sensitivity of the method is adequate to quantitate 0.05 mumol of 5-hydroxytryptophan per liter, in 750 microliter of plasma. No interference by other hydroxyindole compounds was found.

5-Hydroxytryptophan↗
PubMed1977

Theophyllamine and the antiparkinsonian response to levodopa treatment.

In an open preliminary study theophyllamine (theophylline-ethylenediamine) was administered to eight patients with idiopathic parkinsonism showing residual signs of parkinsonism though already in treatment with levodopa. Although theophyllamine in preclinical studies was found effective in potentiating the response to central dopamine stimulation, the drug in the present clinical study was without effect on idiopathic parkinsonism. After a loading dose of aminophylline, 5.6 mg per kilogram given intravenously, a maintenance dose of 0.9 mg per kilogram per hour infused during 2 h resulted in serum levels of theophylline of 23.5 +/- 3.9 mg per liter. 3-methyl-xanthine, a pharmacodynamic active metabolite of theophylline was analyzed in the serum samples. Less than 0.5 mg per liter was found.

Aged↗
PubMed1977

The effect of intraarterial administered aminophylline on cerebral hemodynamics in man.

The dose-effect relationship of intracarotid administered aminophylline on cerebral hemodynamics in man was investigated by means of an intraarterial 133Xenon injection method. A dose dependent vasoconstriction was clearly demonstrated. The maximum efficacy expressed as measured decreased in global cerebral blood flow was 21.9 per cent +/- 6.2 SD. Administration of as little as 1 mg aminophylline produced a measureable vasoconstriction.

Aged↗
PubMed1977

A multifunctional prosthesis control system based on time series identification of EMG signals using microprocessors.

This paper describes a real-time system for separation among several limb functions, in order to provide multifunctional control of an upper-limb prosthesis for above-elbow amputees. The system employs microprocessor hardware and is based on identification of voluntary myoelectric signals resulting from isometric contractions of the musculature of the residual limb, and on subsequent discrimination of these signals for control of the several degrees of motion of the prosthesis. The system requires only one to two electrode sites. (Contrary to the usual placement of electrode pairs directly over specific muscle bellies, to eliminate crosstalk, we prefer to place our electrode pair between muscles so as to acquire the different weakly-correlated signals associated with each of several different voluntary functions). The system satisfies the various practical constraints of weight, volume, and speed, as arise in practical prostheses. Preliminary amputee tests on the system have resulted in an 85 percent success rate using 8-bit double-precision micro-computer hardware.

Adult↗