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Biomedical subjects

L Oreland

Publications and source records attributed to L Oreland.

At least 217 records · Page 12Linked to original sources
PubMed1980

Enzymes related to biogenic amine metabolism and personality characteristics in depressed patients.

Levels of the activity of enzyme systems involved in the synthesis and metabolism of biogenic amines have been linked in several reports in the literature with various psychopathological conditions and with variations in personality characteristics. In particular, significant negative correlations have been reported between levels of MAO-activity and sensation seeking. In the present study levels of MAO and DBH-activity were investigated in a series of 30 depressed patients, admitted consecutively, who completed a new personality inventory, the KSP, assumed to measure relatively stable personality traits. Our findings appeared to be consistent with those of earlier authors in that the most pronounced significant (negative) correlation occurred between MAO-activity levels and the monotony avoidance subscale of the KSP. This particular subscale is aimed precisely at measuring thrill-seeking and bears a close relation to the Sensation Seeking Scale used by other authors. In addition a weak positive correlation was found between the same subscale and levels of DBH-activity. Finally a weak negative correlation emerged between levels of MAO and the Guilt subscale of the KSP.

Adolescent↗
PubMed1980

The effect of lipid-depletion on the kinetic properties of rat liver monoamine oxidase-B.

The extraction of lipids from rat liver mitochondrial membranes by 2-butanone treatment inhibited the activity of membrane-bound monoamine oxidase -A but not -B. For the -B form, the apparent Michaelis constants of the enzyme towards oxygen and the maximum molecular turnover numbers obtained when beta-phenethylamine and benzylamine were used as substrates were not significantly changed by the lipid-depletion procedure, but the values of the Michaelis constant towards benzylamine was significantly increased after lipid-depletion. The differential sensitivity of beta-phenethylamine and benzylamine oxidation to inhibition by Tris-HCl was not changed after lipid-depletion. The results are consistent with the hypothesis that the mitochondrial membrane lipids, while essential for the activity of the -A form of the enzyme in rat liver, play a more subtle modulatory role in the activity of the -B form.

Animals↗
PubMed1979

Monoamine oxidase in platelets and brains of non-psychiatric and non-neurological geriatric patients.

Monoamine oxidase (MAO) activity has previously been found to be high both in brain and in platelets in patients with Alzheimer's disease and low in patients with cycloid psychosis and suicidal behaviour and/or ethanol abuse. To establish if there is a correlation between brain and platelet MAO activities in patients without psychic disease, blood samples from patients in a geriatric ward were collected before death and from 4 different parts of the brain at autopsy. The MAO activities in platelets and brain were then estimated with different substrates. No correlation between the MAO activities in the two tissues was, however, found, regardless of the substrate used.

Age Factors↗
PubMed1979

The inhibition of rat brain monoamine oxidase-B by J-508 (N-methyl-N-propargyl-(1-indanyl)-ammonium hydrochloride), and its use for the titration of this enzyme form.

The interaction between rat brain monoamine oxidase-B and J-508, an analogue of L-deprenil, has been investigated. J-508 inhibits rat brain monoamine oxidase-B in a manner consistent with a 'suicide' reaction, and is so potent an inhibitor that it produces inhibition at concentrations of the same order as those of the enzyme. This property has been used to determine the nature of the changed monoamine oxidase-B activity in the corpus striatum after hemitransection of rat brain.

Alkynes↗
PubMed1977

Brain monoamine oxidase activity after chronic ethanol treatment of rats.

Rats were given chronic treatments with ethanol in two ways: by offering 10% ethanol in water as the only liquid supply for 34 weeks and by exposing the rats to ethanol vapour during 5 h daily for 7 weeks. In this way blood ethanol levels of 1.4-2.3 and 5.5-6.9 mg/ml, respectively, were accomplished. In neither of the cases was brain monoamine oxidase activity changed. The result supports an hypothesis previously advanced that the lowered monoamine oxidase activity found in the brain of a suicide patient was not due to a direct effect of ethanol on alcoholics in the suicide group, but that the low enzyme activity reflected a low monoaminergic activity in the brains of the patients in the suicide group.

Administration, Oral↗
PubMed1977

Changes in psychopathology in relation to EEG variables and visual averaged evoked responses (V.AER) in schizophrenic patients treated with penfluridol or thiothixene.

In a study of 28 schizophrenic in-patients treated with penfluridol or thiothixene, patients were followed with clinical ratings, EEG variables, the mean integrated amplitude (MIA) on both the left and right sides--both with filters with frequency ranges from 7.5 to 13.5 and 0.5 to 25 Hz--as well as its within-patient variance (WPV) on both sides and with both filters, and also with visual averaged evoked responses (V.AER). Moreover, determinations of plasma levels of the drugs were conducted in a search for possible objective measurements of the effects of the treatment, but also to try to find measurements that would make it possible to predict the outcome of treatment. MIA left/right and WPV left/right were found to be the most promising variables to follow the effect of treatment, which were correlated to factors 1 and 2 of the Mårten's S-scale. WPV left/right before treatment was correlated to changes in factor 4 of the S-scale during the trial.

Adult↗
PubMed1977

Neurophysiological measures and visual averaged evoked responses in psychiatric patients. Relationship to monoamine oxidase activity in platelets.

In 57 consecutive patients with psychiatric disorders correlations were sought between the neurophysiological variables - amplitudes and latencies of visual averaged evoked responses (VAER), the proneness to augment or to reduce the amplitude of VAER with increasing stimulus intensity, PAR and PRI, the mean integrated amplitude (MIA) and its within patient variance (WPV) and the monoamine oxidase activity (MAO) in platelets, both with beta-fenylethylamine (MAO1) and with tryptamine (MAO2) as substrate. When multiple correlations with age occurred, a multiple regression was calculated to evaluate the relative importance of each component. MAO1 was found to be significantly correlated to Ampl. N1 and Lat. 2, 3 and 4 of VAER while MAO2 only gave a significant correlation with LaT. 4. As in earlier studies Ampl. N1 was found to be significantly correlated to the content of 5-hydroxyindoleacetic acid in liquor, these measurements seem to be the most important in psychiatric disorders where the monoaminergic systems are supposed to be disturbed.

Adult↗
PubMed1977

Monoamine oxidase activity in gamma-irradiated rat brains.

The short-term effect of gamma-irradiation (single dose, 100 Gy = 10 000 rad) on tth monoamine oxidase activity in the rat brain was investigated. In contrast to other investigations virtually no changes in MAO-activity were found.

Animals↗
PubMed1977

Low platelet monoamine oxidase activity in human alcoholics.

Platelet monoamine oxidase (MAO) activity was found to be significantly reduced in human alcoholics as compared to matched controls. A probable transitory increase in activity was observed during the abstinence phase. The low platelet MAO activity was not due to iron deficiency or to the presence of acetaldehyde. Since we have previously found a lowered MAO activity in the brains of suicide victims, especially in those with a previous history of alcohol abuse, we suggest that low platelet MAO activity reflects a primarily "weak" monoaminergic system in the CNS which causes an increased vulnerability to alcohol abuse and suicidal behaviour.

Alcoholism↗
PubMed1976

Electron microscopic localization of monoamine oxidase in the rat liver.

Two methods have been employed to localize monoamine oxidase activity in the cells of rat liver, using either 2-(2'-benzothiazolyl)-5-stryl-3-(4'-phtalhydrazidyl) tetrazolium chloride (BSPT) or ferricyanide as electron acceptor. With both methods monoamine oxidase activity was found both in the inner and the outer mitochondral membrane, although the outer membrane appeared the most probable location. In addition the BSPT method but not the ferricyanide method, revealed monoamine oxidase activity in the endoplasmatic reticulum. The results obtained by the two methods have been compared and are discussed in view of available biochemical data on monoamine oxidase.

Animals↗