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Biomedical subjects

L Oreland

Publications and source records attributed to L Oreland.

At least 127 records · Page 7Linked to original sources
PubMed1992

Alterations in brain cholecystokinin receptors in suicide victims.

Cholecystokinin (CCK) and benzodiazepine receptor binding characteristics were analyzed in the brain tissue samples from 19 suicide victims and 23 control cases. In the frontal cortex, significantly higher apparent number of CCK receptors and affinity constants were found in the series of suicide victims. These differences between suicides and controls were present in similar proportions when the suicide cases with depressive syndrome or violent or non-violent means of self-killing were compared to matched controls. However, when the samples were split into subgroups consisting of persons either below or over the age of 60 years, significant differences in the CCK receptor characteristics in the frontal cortex were observed only between younger suicides and controls. Furthermore, the younger suicide victims had a higher density of CCK receptors in the cingulate cortex, whereas in older suicides the value was lower as compared to age-matched controls. No difference in benzodiazepine receptor binding was found between control and suicide groups. The results of this investigation suggest that CCK-ergic neurotransmission is linked to self-destructive behaviour, probably through its impact on anxiety and adaptational deficits.

Adolescent↗
PubMed1992

Low platelet gamma-aminobutyrate aminotransferase and monoamine oxidase activities in chronic alcoholic patients.

The activities of gamma-aminobutyrate aminotransferase (GABA-T) and monoamine oxidase (MAO) were estimated in blood platelets from 25 male chronic alcoholics and from 27 healthy male volunteers without histories of alcohol abuse. Based on clinical criteria, the alcoholics were classified into type 1 or type 2 alcoholism. The activity of GABA-T was found to be lower both in type 1 and type 2 alcoholics than in healthy volunteers. With regard to MAO, the platelet activity was found to be significantly lower only in type 2 alcoholics in concordance with previous reports. No significant correlation was found between the activities of GABA-T and MAO in the blood platelets of healthy volunteers. The inhibitory effect of 400 mM ethanol on the platelet MAO activity increased with decreasing concentrations of the substrate phenylethylamine. The degree of inhibition of ethanol on the platelet MAO activity, however, did not differ significantly between alcoholics and controls.

4-Aminobutyrate Transaminase↗
PubMed1992

Platelet monoamine oxidase activity in mentally disordered violent offenders.

The activity of monoamine oxidase (MAO) in blood platelets among criminals undergoing forensic psychiatric examinations was studied. As compulsiveness, disturbed perceptions of reality, etc. are states not known to be related to MAO and yet possibly cause aggressiveness and violence among psychotic patients, we divided the patients into 2 groups, psychotic and nonpsychotic offenders. There was lower MAO activity among violent offenders than among nonviolent offenders. The difference between the violent and nonviolent offenders became greater when the subjects with a history of psychosis were removed. Furthermore, in the group of psychotic offenders, there was no statistical difference between violent and nonviolent individuals in this regard.

Adult↗
PubMed1992

Characterisation of dopamine and serotonin uptake inhibitory effects of tetrahydroaminoacridine in rat brain.

The effects of 1,2,3,4-tetrahydro-9-aminoacridine (THA) on uptake rates of radioactive 5-hydroxytryptamine (5-HT) and dopamine were investigated in rat diencephalon and striatal homogenates, respectively. Six and eight microM of THA were needed to inhibit 50% of dopamine and 5-HT uptake rates. Kinetic parameters, Km and Vmax, using six different concentrations of dopamine and 5-HT were estimated in the presence or absence of THA. A significant decrease in Vmax without any change in Km values was observed for both dopamine and 5-HT in the presence of THA. The results show that THA is a non-competitive uptake inhibitor of dopamine and 5-HT in the nerve terminals. The re-uptake blocking effect of THA on dopaminergic and serotonergic neurones, following THA treatment, might lead to increased levels of these monoamines in brains of Alzheimer patients and contribute in the therapeutic effects of the drug.

Analysis of Variance↗
PubMed1992

Exploring the connections between platelet monoamine oxidase activity and behavior. II. Impulsive personality without neuropsychological signs of disinhibition in air force pilot recruits.

Platelet monoamine oxidase (MAO) activity and serum levels of the adrenal androgen metabolite dehydroepiandrosterone sulfate (DHAS) were measured in 18 male air force pilot recruits and 19 randomly selected male conscripts. Personality scales from three inventories were given, and computerized neuropsychological tests were performed: finger tapping and alternation, reaction time, perceptual maze, perspective fluctuation and lexical decision. The pilot recruits had higher scores in sensation-seeking-related scales suggesting disinhibited behavior in the social sphere, interest in sports and activities involving some danger, and a need for change. They also had higher scores on an impulsivity scale which comprises sensation-seeking content. In the neuropsychological tasks, the pilot recruits were faster in finger-tapping alternation and performed more efficiently in the perceptual-maze test than the conscripts. In a linear discriminant analysis, neuropsychological-task performance discriminated significantly between the pilot and conscript groups. In the biochemical measures, the pilot recruits had higher DHAS levels but similar MAO activity levels compared to the conscripts, which is in contrast to what has been found in other sensation-seeking groups in comparison to controls. This result is in accordance with the normal scores in one of the impulsivity scales in the pilot recruits, and with the absence of signs of disinhibition in neuropsychological tasks. It is proposed that only some aspects of the impulsivity concept might be critical for the association with low MAO activity.

Adolescent↗
PubMed1992

Thrombocyte monoamine oxidase activity and behavior deviances in adolescence.

The frequencies of patients with low thrombocyte monoamine oxidase (MAO) activity (defined as having an activity lower than 1 SD below the mean of a respective control group) were studied in 100 consecutive cases admitted to a clinic for child and youth psychiatry. 41 boys and 26 girls (group I) had behavior disorders, attention deficit disorders and/or alcohol and hashish abuse according to DSM III R. 16 boys and 17 girls had other diagnoses (group II). None of the 2 male patient groups differed significantly from the controls. A significantly higher percentage of the girls in group I had low activity of platelet MAO than in the control group (p = 0.015), while the girls in group II did not differ from the controls. Acting out, antisocial behavior and abuse is less accepted in women than in men. Therefore, the girls in the present study might be either more psychiatrically disturbed or have more deviant personalities than the boys, which might explain why our hypothesis about a lower thrombocyte MAO activity in the adolescents with externalizing symptoms (group I) was verified only in the girls.

Acting Out↗
PubMed1992

Serotonin-stimulated phosphoinositide hydrolysis in platelets from post-withdrawal alcoholics.

It has previously been reported that serotonin-stimulated second messenger formation is inhibited in platelets from alcoholics undergoing detoxification. Serotonin-stimulated signal transduction was therefore analysed in platelets from young post-withdrawal alcoholics to elucidate whether the previously reported inhibition is a state or trait marker of alcoholism. No difference between post-withdrawal alcoholics and controls was found with regard to serotonin-stimulated [32P]-phosphatidylinositol 4,5-bisphosphate hydrolysis or [32P]-phosphatidic acid formation. The results indicate that the inhibited serotonin2 receptor function seen in alcoholics undergoing detoxification is a state-dependent rather than a trait-dependent marker.

Adult↗
PubMed1992

Prediction of suicidal behavior from biologic tests.

Biochemical studies related with suicidal behavior have mainly dealt with monoaminergic and corticosteroidal measures. We used some of these measures in a study of 61 suicide attempters who, except for occasional doses of benzodiazepines, had been medication free for a mean of 16 days. The monoamine metabolites 5-hydroxyindoleacetic acid, homovanillic acid, and 3-methoxy-4-hydroxyphenylglycol were measured in lumbar cerebrospinal fluid (CSF). We found that violent suicide attempters (N = 18) had 5-hydroxyindoleacetic acid concentrations below the median of all patients, whereas the concentrations of 3-methoxy-4-hydroxyphenylglycol were mainly above the median. We found no significant differences between violent and nonviolent (N = 43) attempters concerning CSF homovanillic acid, 24-hour urinary norepinephrine-epinephrine and cortisol, activity of monoamine oxidase in platelets, or post-dexamethasone plasma cortisol. Four patients completed suicide, and 3 of them had CSF 5-hydroxyindoleacetic acid concentrations at or below the median. All completed suicides had CSF 3-methoxy-4-hydroxyphenylglycol concentrations above the median. Urinary measures and platelet monoamine oxidase activity of completed suicides were in the higher concentration ranges. Patients who repeated suicidal behavior after the index investigation had low 24-hour urinary cortisol levels more often than those who did not repeat. Because our subgroups of patients are small, we cannot draw any firm conclusions about the value of our CSF and urinary biochemical findings predicting suicidal behavior. However, our CSF findings in violent suicide attempters are similar to those observed in other studies.

Aged↗
PubMed1991

Quantitative localization of human brain monoamine oxidase B by large section autoradiography using L-[3H]deprenyl.

The distribution of monoamine oxidase B (MAO-B) in the human brain was studied by quantitative autoradiography using L-[3H]deprenyl as a ligand. Two postmortem brains from patients without any known neurological diseases were used in this study. Cryosections of 100 microns thickness were taken on tape/paper and transferred to gelatinized glass plates. The sections were incubated with 10 nM L-[3H]deprenyl for 1 h and exposed to a film at 4 degrees C for 4 weeks. The autoradiograms were analyzed by computerized densitometry. High L-[3H]deprenyl binding was observed in caudate nucleus, putamen, cingulate gyrus and insula cortex. Moderate to low binding was seen in globus pallidus, temporal and parietal cortex and in various thalamus nuclei. Occipital cortex showed the lowest binding among the cortex regions and white matter the lowest among all the regions studied. All the regions in case 2 (aged 67) showed higher degree of binding when compared with case 1 (aged 58), which is in agreement with previous results showing an increase in MAO-B activity with age. When the specific binding of L-[3H]deprenyl was plotted against the MAO-B activities estimated biochemically in punches from the same areas, a high positive correlation was found.

Adult↗
PubMed1991

GABA-transaminase activity in rat and human brain: regional, age and sex-related differences.

The activity of 4-aminobutyrate:2-oxoglutarate transaminase (GABA-T) has been investigated in the rat and human brain. Both rat and human brain GABA-T retained its full activity for at least 2 months and with a loss of less than 10% after 6 months when frozen at -20 degrees C as tissue parts. There was a loss of activity of mouse brain GABA-T of about 15% per 24 hours postmortem. In the rat brain, GABA-T activity varied from low values in cortex and hippocampus to high in brain stem and cerebellum. There was a significant increase of GABA-T activity with age from 1 to 6 weeks and a significant reduction of the activity with age thereafter. Male rats had significant higher activity than female rats. In the human brain, GABA-T activities were measured in twelve regions of autopsied brains from 10 adult control subjects. No difference was found between the activities in the left and right sides. There is considerable variation in enzyme activity across the brain, with low activities in e.g. pons and medulla oblongata and high activities in e.g. caudatus, substantia nigra and hypothalamus. The activity of the enzyme is significantly different both between brain regions and between individuals.

4-Aminobutyrate Transaminase↗
PubMed1991

Vitamin B12-induced reduction of platelet monoamine oxidase activity in patients with dementia and pernicious anaemia.

Platelet monoamine oxidase (MAO) activity has previously been shown to be increased in patients with senile dementia of Alzheimer type (SDAT) and in patients with megaloblastic anaemia. Moreover, low serum B12 levels were found to be 4-5 times more frequent in SDAT compared with an unselected population of similar age. In the present investigation, platelet MAO activity was estimated in 14 SDAT patients with relatively low serum B12 levels and in 4 patients with pernicious anaemia. Before B12 therapy, platelet MAO activity was significantly increased in both patient groups compared with a control group. After B12 therapy, platelet MAO activity was significantly reduced in both patient groups to apparently normal levels. The present results show that B12 status is a controlling factor of platelet MAO activity and confirm that a significant connection exists between vitamin B12 deficiency and primary degenerative dementia disorders, such as SDAT.

Aged↗
PubMed1991

Brain gamma-aminobutyrate transaminase and monoamine oxidase activities in suicide victims.

The activity of gamma-aminobutyrate amino-transferase (GABA-T) and monoamine oxidase (MAO-A and -B) was measured in 42 postmortem human brains. Three brain regions (frontal cortex, cingulate cortex and hypothalamus) from 23 controls without known neurological or psychiatric disorder and from 19 suicide victims were analysed. The suicide victims were classified according to the use of violent and non-violent methods and to the presence or absence of a known history of depressive disorder. No difference was found between the series of suicide victims and the control subjects with regard to GABA-T activity. Carbon monoxide poisoning and death by drug overdose, however, were found to reduce the activity. The MAO-B activity did not differ between the groups. With MAO-A, however, a significant elevation (t = 2.01; P less than 0.05) was found in the hypothalamic region of the suicide victims. The difference seemed to be confined to the subgroup of suicides with a record of depressive disorder.

4-Aminobutyrate Transaminase↗
PubMed1991

Monoamine oxidase B in brains from patients with Alzheimer's disease: a biochemical and autoradiographical study.

In vitro quantitative autoradiography using [3H]L-deprenyl, an irreversible and preferential inhibitor of monoamine oxidase B, was performed to investigate the localization of the enzyme in brains from senile dementia of Alzheimer type and control cases. Brains from three male patients with the clinical diagnosis of senile dementia of Alzheimer type and from three male control patients, without any known clinical history of neurological disorder, were obtained at autopsy. Cryosections of 100 microns thickness were mounted on gelatinized glass plates and dried over desiccant for one week at -20 degrees C. The sections were incubated with 10 nM [3H]L-deprenyl for 1 h and then exposed to film for four weeks. The autoradiographs were analysed by computer-assisted densitometry. Monoamine oxidase-B activities were also estimated in 1% homogenates from 10 different regions, using 10 microM beta-[ethyl-14C]phenylethylamine, in order to study the consonance between the autoradiographical and biochemical techniques. Both [3H]L-deprenyl binding and monoamine oxidase-B activities in senile dementia of Alzheimer type were higher than in the controls in all brain regions studied. The increase was highest in the white matter (about 70%) and in the order of 20-50% in the various gray matter regions. A high correlation coefficient (r approximately 0.9) was obtained between [3H]L-deprenyl binding and monoamine oxidase-B activity, both in the senile dementia of Alzheimer type and in the control brains.

Aged↗
PubMed1991

Personality traits and platelet monoamine oxidase activity in alcoholic women.

Twenty-nine women, sent to an inpatient treatment facility for rehabilitation and social training after treatment for heavy alcohol abuse, were compared with 29 female students of pharmacy or medicine with regard to platelet monoamine oxidase (MAO) activity and extraversion-impulsivity and anxiety-proneness personality traits. The alcoholic females were found to have slightly lower platelet MAO activity than the controls, the difference being considerably smaller than that previously found between male alcoholics and male controls. The personality pattern of the female alcoholics is in line with that previously found in alcoholic males. Thus, the female alcoholics were characterized by high anxiety proneness, impulsive acting-out behaviour, sensation seeking, social withdrawal, and a hostile attitude.

Alcoholism↗
PubMed1991

Peripheral serotonergic markers in patients with suicidal behavior.

Peripheral serotonergic parameters were studied in 17 patients with a history of suicidal behavior and in 17 age- and sex-matched healthy controls. Serotonin2 receptor function in platelets, measured as serotonin-induced [32P]phosphatidylinositol 4,5-bisphosphate hydrolysis, was significantly higher in patients than in age- and sex-matched controls. Increased serotonin2 receptor transduction was not correlated to psychiatric diagnosis, drug treatment or a history of violent suicide attempt. Monoamine oxidase activity was lower in platelets from patients with a history of suicidal behavior than in controls. In addition, whole blood serotonin was analyzed but no significant alterations were found in blood from patients.

Adult↗
PubMed1991

Platelet monoamine oxidase activity in type 1 and type 2 alcoholism.

Earlier studies have identified at least two distinct subtypes of alcoholism. Type 2 is characterised by high heritability, early onset, frequent social complications and mixed misuse. With regard to temperament, the type 2 alcoholics score high in impulsiveness and sensation-seeking behaviour. Type 1 alcoholics have a later onset, lower degree of heritability and rarely there is misuse of illegal drugs. In the present study, 37 type 1 and 62 type 2 male alcoholics were compared with 36 male controls with regard to platelet monoamine oxidase (MAO) activity, which is a stable biological marker, inversely correlated to personality traits such as impulsiveness and sensation seeking. The platelet MAO activity was found to be lower in type 2 alcoholics when compared both with healthy controls and with type 1 alcoholics. Also, the type 1 alcoholics had lower platelet MAO activity than the controls. The result confirms a previous study and validates the subclassification of alcoholism according to the type 1 and 2 concept. This should be of value for future studies concerning etiology, epidemiology, treatment and prevention of alcoholism.

Alcoholism↗
PubMed1991

Monoamine oxidase, dopamine and Parkinson's disease.

Four aspects about monoamine oxidase (MAO; E.C. 1.4.3.4) are of obvious interest in relation to Parkinson's disease and its treatment with the irreversible and selective MAO-B inhibitor L-deprenyl and are discussed in this review: 1) To what extent the two forms of MAO are of importance for the deamination of dopamine and to what degree MAO localised inside and outside of dopaminergic nerve terminals contributes 2) The kinetics of the MAO-protein, i.e. the rate of recovery of MAO after irreversible inhibition. 3) To what extent MAO may be changed as a consequence of the pathophysiological processes. 4) To what extent MAO may be involved as a force in the pathophysiological processes.

Animals↗