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Biomedical subjects

M Lind

Publications and source records attributed to M Lind.

At least 109 records · Page 6Linked to original sources
PubMed1982

Clinical experience with the objective symmetry detector method for gammaencephalography.

The objective symmetry detector method for gammaencephalography previously described has been further developed. A rapid micro-computerized automatic measuring device has been constructed and the method used in screening of neurologic patients. The previously chosen classification boundaries between normal and pathologic isotope distributions were not entirely satisfactory for clinical screening of patients with neurologic symptoms. By use of new classification boundaries, 87 per cent of patients with brain tumours could be separated from patients with neurologic symptoms but without gross brain lesions and from neurologically healthy subjects.

Adult↗
PubMed1982

Oxidation of (R)- and (S)-propranolol in human and dog liver microsomes. Species differences in stereoselectivity.

Propranolol is an adrenergic beta receptor antagonist whose kinetics is complicated by dose-dependency, formation of active metabolites and stereoselective availability. To get some insight of the possible metabolic factors behind this, we have incubated the two optical isomers (R)- and (S)-propranolol with human and dog liver microsomes. Propranolol and its oxidized metabolites 4-hydroxypropranolol (4-OH-P) and N-desisopropylpropranolol (nor-P) were analyzed using high-performance liquid chromatography and fluorometric detection. The oxidation rates varied markedly between human livers. Most of metabolized propranolol was recovered as 4-OH-P and nor-P and more propranolol was oxidized than glucuronidated. Formation rates of 4-OH-P and nor-P were approximately half-maximal at propranolol concentrations than can occur in the liver in vivo. The ratio between formation of these metabolites varied markedly between livers. Human livers formed 4-OH-P and nor-P most rapidly from (R)-propranolol, whereas dog livers formed 4-OH-P most rapidly from (S)-propranolol. We suggest that the interindividual differences in the capacity of the livers to metabolize propranolol largely should contribute to the kinetic variations observed between patients in vivo and the gradual saturation of 4-hydroxylation and N-desisopropylation of propranolol are likely to contribute to the dose-dependent kinetics.

Adult↗
PubMed1977

First pass hydroxylation of nortriptyline: concentrations of parent drug and major metabolites in plasma.

Nortriptyline was given orally and intramuscularly to six depressed patients. Plasma concentrations of parent drug and the unconjugated and conjugated principal metabolite, 10-hydroxynortriptyline, were determined by mass fragmentography. There was a significant decrease in the area under the nortriptyling plasma concentration- time curve after the oral route of administration, whilst the elimination rate was unchanged. With the oral dose, plasma concentrations of the metabolites were higher and peaked earlier than after intramuscular administration, whilst the opposite was true for the parent compound. This proves that the difference in bioavailability between the two routes of administration was due to first pass metabolism. As determined from the ratio between corresponding areas, the relative bioavailability of the oral dose was 66 +-21 S.D. per cent. This fraction is higher than that reported previously when intravenous nortriptyline was used as the reference dosage form.

Administration, Oral↗
PubMed1977

Effect of pentobarbital on the disposition of alprenolol.

Alprenolol was administered orally and intravenously to 5 healthy subjects before and after 10 to 14 daily doses of 0.1 gm pentobarbital. The area under the plasma concentration time curve after an oral 200-mg dose decreased from 706 +/- 277 to 154 +/- 48 ng/ml-hr (mean and SD) with the barbiturate treatment, but there was no significant change in elimination rate. The change in area corresponded to an increase in extraction by the liver from 0.72 +/- 0.13 to 0.93 +/- 0.01. The disposition of a 5.0-mg intravenous dose of alprenolol did not change significantly after pentobarbital treatment. There was no indication of a marked change in hepatic blood flow estimated from the clearance of alprenolol after intravenous administration. It is concluded that pentobarbital administration induces the metabolism of alprenolol in man and that the pharmacokinetic theories derived for hepatic extraction of drugs subject to a high metabolic clearance can be successfully applied.

Administration, Oral↗
PubMed1976

Objective symmetry detector method for gammaencephalography. V. Variation in the subjective analysis of brain scintigrams.

The variation caused by the subjective interpretation of brain scintigrams was evaluated and found considerable. It was concluded that the objective analysis of results offered by the objective symmetry detector method for gammaencephalography is advantageous, especially in the screening of large patient materials with a low incidence of brain lesion cases.

Brain Diseases↗
PubMed1975

Objective symmetry detector method for gammaencephalography. IV. Investigation of brain tumours.

Sixty-six cases with possible brain tumour were objectively classified as having normal or abnormal 99TcmO4 distribution in the skull recorded by the symmetry detector method for gammaencephalography. The diagnostic accuracy in 37 confirmed tumour cases was about 95 percent. Astrocytomas I-II were seperated from astrocytomas III-IV by the degree of abnormality, and meningiomas were seperated from astrocytomas by diverging time-dependent changes in the pathologic isotope accumulation. The high diagnostic accuracy was obtained in spite of low spatial resolution and simplicity of the method. The careful choice of evaluation parameters and the restriction of their normal variance were necessary and effective in optimizing the method.

Astrocytoma↗