Search PubMed⌕ Search

Biomedical subjects

Y Agid

Publications and source records attributed to Y Agid.

At least 523 records · Page 29Linked to original sources
PubMed1984

[Parkinson syndrome, frontal tumor and L-dopa].

A case of frontal astrocytoma revealed by an extrapyramidal syndrome and improved by L-DOPA treatment is reported. Thus, at least partly, parkinsonian signs were provoked by dysfunction of the central dopaminergic systems.

Adult↗
PubMed1984

[Meningo-myelitis with a favorable course after measles vaccination].

A 27 year-old woman complained of symptoms and signs due to a meningo-myelitis, 5 days after anti-rubella vaccination. Among the earliest symptoms she experienced pain and sensory deficit in the inoculated arm. The disease worsened until the 15th day, then improved spontaneously.

Adult↗
PubMed1983

A subcortico-cortical cholinergic system is affected in Parkinson's disease.

CAT activity was decreased in the frontal cortex and the substantia innominata of parkinsonian subjects, post-mortem. The decrease was greater in the frontal cortex of parkinsonians with dementia. The density of muscarinic cholinergic receptors increased in the cortex. This increase was inversely correlated with tremor. The effects on these parameters of both neuronal degeneration and anticholinergic therapy are discussed.

Aged↗
PubMed1983

Parkinson's disease affects differently Met5- and Leu5-enkephalin in the human brain.

When measured in post-mortem human control brains, the ratio of Met5-enkephalin levels to those of Leu5-enkephalin varied from 1 to 13 in the 11 areas examined. In parkinsonian brains a significant reduction in the levels of both peptides was found in the pallidum and putamen whereas only Met5-enkephalin levels were decreased in the substantia nigra and ventral tegmental area. Therefore, Met5-enkephalin and Leu5-enkephalin may be located (at least partly) in different neuronal populations in the human brain.

Brain↗
PubMed1983

Somatostatin and dementia in Parkinson's disease.

The concentrations of somatostatin in the cortex, hippocampus and caudate nucleus of subjects with Parkinson's disease were determined by radioimmunoassay. Somatostatin levels in the frontal cortex were significantly reduced in Parkinsonian subjects who were slightly or severely demented compared to controls and to non-demented Parkinsonians. Significant reductions were also observed in the hippocampus and entorhinal cortex of severely demented subjects.

Aged↗
PubMed1983

[3H]imipramine binding in subcellular fractions of rat cerebral cortex after chemical lesion of serotonergic neurons.

The specific high affinity binding of [3H]imipramine was investigated in subcellular fractions of rat cerebral cortex before and after chemical denervation of serotonergic neurons. In control animals the proportion of the total number of [3H]imipramine binding sites in the nuclear (N), heavy mitochondrial (M), light mitochondrial (L) and microsomal (P) fractions corresponded respectively to 3, 45, 16 and 36% of the total number of binding sites. After chemical lesion of serotonergic neurons with 5,7-dihydroxytryptamine (5,7-DHT) the density of [3H]imipramine binding sites in fractions M and L was decreased by 42 and 52% respectively. In these experiments the uptake of [3H]5-HT in fractions M and L decreased by approximately 80%. The Bmax of [3H]imipramine binding in fraction P was decreased by 80% after chemical denervation with 5,7-DHT. In the control group there was no detectable [3H]5-HT uptake while the endogenous serotonin levels in fraction P were rather low. Our results support the view that the high affinity binding of [3H]imipramine is partly located on serotonergic nerve terminals. The significance of the [3H]imipramine binding sites present in the microsomal (P) fraction remains to be clarified.

5,7-Dihydroxytryptamine↗
PubMed1983

Reduction of cortical dopamine, noradrenaline, serotonin and their metabolites in Parkinson's disease.

Dopamine, 3,4-dihydroxyphenylacetic acid, homovanillic acid, noradrenaline, serotonin and 5-hydroxyindoleacetic acid concentrations were measured in several cortical areas, hippocampus and, for comparison, in the caudate nucleus, from control subjects and parkinsonian patients. Substantial amounts of these compounds were detected in hippocampus, and entorhinal, cingulate and frontal cerebral cortices of control subjects. In patients who had discontinued L-DOPA at least 4 days before death (group I), the levels of dopamine and its metabolites were reduced in these cortical areas, although to a lesser extent than in the caudate nucleus. In patients on continuous L-DOPA treatment (i.e. having received the last dose of L-DOPA 0-24 h before death, group II), cortical dopamine levels were less reduced than in group I patients and dopamine metabolite levels were similar to those of controls. The ratio of the concentrations of homovanillic acid to dopamine was increased in the caudate nucleus and entorhinal cortex but not in the other cortical areas of group I parkinsonian patients. Cortical noradrenaline concentrations were also diminished, the decrement being similar in groups I and II. A reduction of serotonin and its metabolite in the caudate nucleus and hippocampus and a diminution of serotonin levels in the frontal cortex were observed in group I patients. In these patients, the 5-hydroxyindoleacetic acid to serotonin ratio was increased in the caudate nucleus and frontal cortex but not in the other cortical areas. The results are discussed in relation to the pathophysiology of the psychiatric and cognitive disturbances observed in some parkinsonian patients.

Aged↗
PubMed1983

Tyrosine hydroxylase and methionine-enkephalin in the human mesencephalon. Immunocytochemical localization and relationships.

The immunocytochemical localization of tyrosine hydroxylase (TH) and methionine-enkephalin (met-enkephalin) was determined at two representative caudal and rostral levels of the human mesencephalon. Four main groups of catecholaminergic neurons were delineated, situated in the substantia nigra and the lateral, ventromedial and dorsomedial tegmentum, extending over several cytoarchitectonic divisions. They matched fairly well the dopaminergic cell groups described in monkey midbrain. TH-like immunoreactivity and neuromelanin were closely related in neurons of substantia nigra, but less so in the other groups. A widespread met-enkephalinergic innervation was observed in most areas containing catecholaminergic neurons. It followed a characteristic pattern: homogeneous and very dense in the lateral and posterior portions of substantia nigra; patchy and less dense in the other areas, the medio-ventral and periaqueductal gray being only sparsely innervated, in contrast to observations in rodents. Dopaminergic cell bodies surrounded by met-enkephalinergic varicosities were seen in most groups, particularly in the lateral substantia nigra and medioventral tegmentum. The topography of met-enkephali-like immunoreactive terminals in the substantia nigra was reminiscent of the distribution of neostriatal and pallidal afferents.

Aged↗
PubMed1983

Antiparkinsonian and antidepressant effects of high doses of bromocriptine. An independent comparison.

Ten depressed parkinsonian patients were treated with high doses of bromocriptine (rang 85-220 mg/day). Changes in the parkinsonian and depressive symptomatologies were independently evaluated by a neurologist and a psychiatrist. Rating took place before treatment after wash-out and again 8 days later. Results show a significant mean improvement of both depressive and parkinsonian symptomatologies. However, there was no correlation between the two therapeutic effects in the 10 patients. Clinical and biological implications of these heterogeneous patterns are discussed.

Adult↗
PubMed1983

Striatal GABAergic neuronal activity is not reduced in Parkinson's disease.

The content of gamma-aminobutyric acid (GABA) and the activities of glutamic acid decarboxylase (GAD) and tyrosine hydroxylase (TH) were measured in whole putamen obtained at autopsy from 13 patients dying with idiopathic Parkinson's disease and 13 appropriate control subjects. Mean GABA content was significantly elevated (by 28%) in the putamen of the Parkinson's disease patients. TH activity was markedly reduced, while there was no significant reduction of GAD activity in the putamen of these patients. GABA content was also measured in both sides of the striatum in rats which had received unilateral injections of 6-hydroxydopamine (6-OHDA) in the vicinity of the axons of the nigrostriatal projection. Mean GABA content was found significantly elevated (by 33%) in the ipsilateral striatum. Loss of dopaminergic nigrostriatal neurons, in both human Parkinson's disease and in the rat 6-OHDA model, is accompanied by increased striatal GABA content. The assumption that GABAergic neurotransmission is reduced in the striatum in Parkinson's disease may not be correct.

Amino Acids↗
PubMed1983

[Neurotransmission].

Neurotransmission is necessarily difficult to investigate in the brain, particularly in the human brain. However the striking development of anatomical, biochemical and electrophysiological technics now enables a more accurate analysis of the neurones, the neuronal systems and the synapses. The neurones can no longer be considered as unipolarized transmitting nerve units only. They inform other neurones through thousands of nerve terminals, but also receive informations through a great number of afferences the regulation of which involves dendritic release of neurotransmitters. The neurones spread in such spread in such intricated networks that a change in the activity of one neuronal system has an immediate effect on all parts of the brain. We begin to understand the biochemical events taking place within the synapses due to the development of molecular biology, particularly in studies that have characterized the receptor site. The complexity of the organization of the synaptic cleft appears greater inasmuch that one considers the evidence of various types and even sub-groups of defined neurotransmitter receptors (i.e. pre- and postsynaptic, linked or not linked to cyclic-AMP) as well as the discovery of a new class of putative neurotransmitters (the neuropeptides).

Brain↗
PubMed1983

Effect of a methionine-enkephalin analog in Huntington's disease.

The methionine-enkephalin analog FK 33-824 was administered intravenously to 12 patients with Huntington's disease in a crossover double-blind study. The abnormal involuntary movements (AIM) were not improved after administration of 0.5 mg of FK 33-824. A significant decrease in the AIM score was observed only 150 and 180 min after injection of high doses (2 mg); however, the difference between the active drug and the placebo was never statistically significant. These results are discussed in terms of experimental data suggesting a relationship between methionine-enkephalin and dopamine neurons in the brain and of methionine-enkephalin deficiency in the brain of patients with Huntington's disease.

Adult↗