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Biomedical subjects

T Magnusson

Publications and source records attributed to T Magnusson.

At least 73 records · Page 4Linked to original sources
PubMed1981

Effects of hypophysectomy, adrenalectomy and (-)-propranolol on ethanol-induced decrease in plasma amino acids.

In previous studies we have demonstrated that an acute dose of ethanol cause an immediate decrease in most plasma amino acids in both man and rat. This effect of ethanol is partly inhibited by the beta-adrenergic antagonist (-)-propranolol, partly by adrenalectomy or hypophysectomy and almost completely by a combination of adrenalectomy with (-)-propranolol. This finding suggests an involvement of both beta-adrenergic mechanisms and steroids from the adrenal cortex in the ethanol-induced decrease in plasma amino acids.

Adrenalectomy↗
PubMed1981

The activities of monoamine oxidase-A and -B, succinate dehydrogenase and acid phosphatase in the rat brain after hemitransection.

The activities of monoamine oxidase-A and -B were determined in four brain regions (limbic system, occipito-temporal cortex, hemispheres and striatum) of the rat 0, 3, 6, 9 and 14 days after hemitransection of the left side. No larger or consistent change in the activity of monoamine oxidase-A towards 5-hydroxytryptamine was found for the left (hemitransected) side with respect to the right side for any of the rats. The monoamine oxidase-B activity towards beta-phenethylamine increased in the left side striatum to a significant level by 3 days, and in the hemispheres and occipito-temporal cortex on the left side, with respect to the right side by 9 days, but no significant changes were found for the limbic system. A small decrease in the activity of succinate dehydrogenase was found in the striatum on the left side by 9 days after hemitransection, but no change in the activity of acid phosphatase was found in this brain region.

Acid Phosphatase↗
PubMed1980

Prevalence of recurrent headache and mandibular dysfunction in patients with unsatisfactory complete dentures.

The prevalence of headache and mandibular dysfunction was studied in 43 patients with unsatisfactory complete dentures waiting for prosthodontic treatment at the Dental Clinic of the National Dental Service in Jokkmokk, Sweden. In addition to answering a questionnaire, all patients underwent a clinical-functional examination of the masticatory system. Seventeen patients (40%), 15 women and two men, reported recurrent headache. 63% of the men and 83% of the women showed marked clinical signs of mandibular dysfunction. A significant correlation between headache and mandibular dysfunction was found. The low representation of complete denture wearers in clinical series of patients referred for treatment of mandibular dysfunction may be due to a reduced propensity to seek help and a greater willingness to accept a certain degree of dysfunction compared with other people.

Adult↗
PubMed1980

Changes in recurrent headaches and mandibular dysfunction after various types of dental treatment.

A follow-up study was performed in 128 patients who had started dental treatment at the Faculty of Odontology in Göteborg one year previously. 58 patients had been referred to the Department of Stomatognathic Physiology for investigation and treatment of mandibular dysfunction (TMJ patients) and 70 patients had come to the clinic for conventional dental treatment (dental patients). In addition to answering a questionnaire, all patients underwent a clinical-functional investigation of the masticatory system. 70% of the TMJ patients who had previously reported headaches stated that their headaches now occurred less often. 42% also stated that the headaches were less severe than previously. Only one TMJ patient stated that he had a headache more often and that it was more painful than previously. In the dental patients improvement and deterioration occurred approximately equally often. A decrease of the clinical dysfunction index was observed in the TMJ patients. There was no change in the dental patients. The prevalence of mandibular dysfunction in the TMJ group, however, was still significantly higher than in the dental patients. The study shows that treatment directed towards functional disturbances of the masticatory system has a beneficial effect on mandibular dysfunction and that many patients who suffer from recurrent headaches experience a reduction of the frequency and severity of their headaches after this treatment.

Bruxism↗
PubMed1980

Intra- and inter-observer variation in functional examination of the masticatory system.

Occlusal variables and clinical signs of functional disturbances of the masticatory system were studied with respect to intra- and inter-observer differences in 11-year-old children and adults. Inter-observer differences were present in all registrations made. They were relatively small when measuring the movement capacity of the mandible but large when measuring the distance between RP-IP. The clinical dysfunction index was recorded with an agreement of 82% (Scott's pi = 0.69) in children, 73% (Scott's pi = 0.58) in adults. Repeated registrations performed 5 weeks apart in the child group showed high agreement while repeated registrations with an interval on one year in the adult group revealed considerable variations for mandibular mobility and for the clinical dysfunction index. The study showed that intra-observer constancy is larger than that between different observers. Thus repeated registrations in longitudinal studies should be done by the same observer. In order to control unavoidable observer errors, and to minimize the influence of the large, normal fluctuation of clinical signs that are known to occur, longitudinal studies should include control groups.

Adolescent↗
PubMed1979

Opposite effects of naloxone on substance P-induced changes in brain DOPA synthesis and in locomotor activity in rats.

Intracerebroventricular injection of substance P (SP) enhanced the synthesis of dopamine and noradrenaline (measured as increase in DOPA formation after inhibition of the aromatic L-amino-acid decarboxylase) in rat brain. These biochemical effects were blocked in most brain regions by pretreatment with naloxone. SP also induced vasodilation, salivation and increased locomotor activity. These effects were not antagonized, but, in the case of locomotor activity, potentiated by naloxone. The data suggest the existence of specific SP-containing neuronal pathways for behavior, which pathways are not related to those regulating the synthesis of brain catecholamines.

Animals↗
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↗
PubMed1978

Neurotensin and its amide analogue [Gln4]-neurotensin: effects on brain monoamine turnover.

Intracerebroventricularly administered neurotensin and [Gln4]-neurotensin (50-200 microgram) increased the formation of Dopa in different brain regions of rats after inhibition of the aromatic L-amino acid decarboxylase. For both neuropeptides these increases were dose dependent (20-150%). In the corpus striatum [Gln4]-neurotensin was twice as active as neurotensin and it tended to be more active also in other brain regions. The brain tyrosine concentrations were also increased. [Gln4]-neurotensin (100-200 microgram) following inhibition of the aromatic L-amino acid decarboxylase, increased the accumulation of 5-hydroxytryptophan in all brain regions by 30-60%. In contrast, neurotensin was completely inactive. In both cases the brain tryptophan concentrations were increased. Both neurotensin and [Gln4]-neurotensin also accelerated the disappearance of dopamine, noradrenaline and 5-hydroxytryptamine after inhibition of monoamine synthesis. These results show an increased brain monoamine turnover induced by both neuropeptides.

Animals↗
PubMed1978

Recurrent headaches in relation to temporomandibular joint pain-dysfunction.

Two groups of 80 patients, one referred because of mandibular dysfunction and one seeking dental treatment, completed questionnaires concerning recurrent headaches. The function of the masticatory system of all patients was afterwards examined clinically. The investigation showed that clenching of teeth was correlated to the severity of headache. The frequency and severity of headache varied also with the severity of mandibular dysfunction. Of the variables included in the dysfunction index, only masticatory musculature painful to palpation was found to have a distinct relationship to headaches. This implies that functional treatment is indicated in patients with headaches and tendernes of the masticatory musculature. Functional examination of the masticatory system should therefore be included in investigations of recurrent headaches.

Bruxism↗
PubMed1976

Effect of synthetic substance P on monoaminergic mechanisms in brain.

Synthetic substance P has been discovered to stimulate significantly the formation of dopa in the limbic, striatum, hemisphere and diencephalon regions of the brain and the lower brain stem. There was no effect upon 5-hydroxytryptophan formation or on tryptophan or tyrosine levels. After inhibition of monoamine synthesis by N'-(DL-SERYL)-N2-(2, 3, 4-trihydroxybenzyl)hydrazine, substance P significantly accelerated the disappearance of dopamine, noradrenaline and 5-hydroxytryptamine. Substance P appears to stimulate monoaminergic neurons in the brain and to serve as an excitatory transmitter in nerve terminals impinging upon dopaminergic cell bodies. A similar stimulation of noradrenaline and 5-hydroxytryptamine indicate a similar transmitter role for noradrenergic and serotonergic neurons. These data strengthen questions about the possible clinical influence of substance P in disease states involving monoaminergic mechanisms including Parkinsonism and schizophrenia.

Animals↗