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Biomedical subjects

R Tissot

Publications and source records attributed to R Tissot.

At least 181 records · Page 10Linked to original sources
PubMedDate not supplied

[Erythrocyte membrane transports of monoamine precursor amino acids in schizophrenia].

We have determined the erythrocyte membrane uptake of the monoamine precursors L-tyrosine (L-TYR) and L-tryptophane (L-TRYP) in 72 patients with schizophrenia: 21 without neuroleptic treatment and not depressed, 15 with neuroleptic treatment and depressed, 33 without neuroleptic treatment, 27 depressed, compared to: 59 control subjects, and 54 depressed patients. We found that the ratio of L-TYR facilitated membrane diffusion to that of L-TRYP is: decreased when the patients are depressed, increased when they are untreated. When untreated patients receive neuroleptics and are depressed, the ratio tends to equal that of depressed patients'. The meaning of these anomalies is analysed, using our up-to-date knowledge of the erythrocytes's role in uptaking and dispatching the human body amino-acids, and of the role of these uptakes in regulating the functional monoamine balance. We postulate that in depressions, Parkinson's disease and schizophrenia, a change of membrane fluidity occurs, being decreased in depressions and Parkinsons's disease, and increased in schizophrenia.

Adult↗
PubMedDate not supplied

[Neuropsychological functioning in hebephrenic patients. Comparison between visual and auditory stimuli initially projected either in one or in both cerebral hemispheres].

The performances of 14 hebephrenic patients and 14 normal subjects were studied through visual and auditory tests concerning the comparison of the number of stimuli projected either in the left, or in the right, or in both cerebral hemispheres. Schizophrenic patients were less efficient than normal subjects and, in both populations, no difference in the performances with regard to the locus of projection was observed. This suggests that information processing in schizophrenia might be deficient not only at the level of interhemispheric connections, but also in intrahemispheric functioning.

Acoustic Stimulation↗
PubMedDate not supplied

[Huntington chorea. Anatomoclinical and genetic study of 17 cases].

Seventeen cases of Huntington's chorea have been studied on a clinical and anatomopathological basis. Fourteen genealogical trees have been established. Clinically, involuntary movements of choreic type and an impairment of higher brain functions are constant symptoms. Gait disorders, dysarthria and a tendinous hyperreflexia are usual (present in 95, 95 and 80% of cases). Anorexia, muscular hypotony and dysphagia are also frequent (present in 75, 60 and 50% of cases). The neuropathological examination shows macroscopically a neostriatal atrophy in 90% of cases and a cerebral cortical atrophy in 75%. Microscopically, a neuronal loss--mainly in small cells (Golgi II)--is evident in the neostriatum of all the cases. The pallidum is also affected, but to a lesser degree. A cortical cell loss is present in 90% of the cases, mainly in layers III, IV, V and sometimes also in layer VI of frontal and parietal lobes. In 75% of the cases, a cortical gliosis is noticed, mostly at the level of the frontal pole.

Adult↗
PubMedDate not supplied

[Erythrocyte membrane transport of tyrosine and tryptophan and plasma level of MHPG in depressive disorders].

Both plasma MHPG level and red blood cell membrane transports (TM) of L-tyrosine (L-TYR) and L-tryptophan (L-TRY) were evaluated in 29 depressed patients and compared to 16 control subjects. On the basis of MHPG plasmatic levels, we were able to define two subgroups in the depressed population showing a biological homogeneity: in the first one, both MHPG level and TYR TM decreased, while in the second one neither of these indices were disturbed. These biological features were not related to the nosographic subgroups. Bipolar depressed subjects showed a decrease in both MHPG and TYR TM; unipolar depressed subjects exhibited a decrease in both MHPG and TYR TM associated to an increase in TRY TM, whereas no change was found in dysthymic disorders. The time course of MHPG and MT were desynchronized if followed during the antidepressant treatment. At day 7, MHPG level increased significantly, while clinical improvement showed a normalisation of MHPG and TYR TM.

Adult↗
PubMedDate not supplied

Immunohistochemical mapping of delta sleep-inducing peptide in the cat brain and hypophysis. Relationships with the LHRH system and corticotropes.

Using the indirect immunofluorescence method, the distribution of the delta sleep-inducing peptide was studied in the cat brain and hypophysis. Delta sleep-inducing peptide-like-immunoreactive cell bodies mostly visualized in colchicine-pretreated animals were mainly found scattered throughout the diagonal band of Broca, the ventral septum and the anterior hypothalamic areas. A few immunoreactive cell somata were also seen in the ventrolateral hypothalamic area and more occasionally in the triangular septal nucleus. The heaviest concentrations of delta sleep-inducing peptide-like-immunoreactive varicose fibres and terminal-like structures were observed in the septo-preoptic region, in the median eminence and pituitary stalk. Some other brain regions supplied with few delta sleep-inducing peptide-immunoreactive fibres included the fimbria-fornix, the dorsal part of the subfornical organ, the medial habenular nucleus and more caudally, the periaqueductal gray. Elution-restaining experiments revealed that delta sleep-inducing peptide-like immunoreactivity frequently occurred in luteinizing hormone-releasing hormone-immunoreactive neurons and vice versa. At the pituitary level, delta sleep-inducing peptide-like immunoreactivity was detected in most, if not all, melanocorticotropes of the pars intermedia and further in a large subpopulation of corticotropes mainly located in the zona tuberalis of the pars distalis. Taken together these anatomical findings support the view that delta sleep-inducing peptide (or a closely related molecular form) could play a modulatory role at various levels of the hypothalamo-pituitary system.

Animals↗
PubMedDate not supplied

[Changes in the kinetics of erythrocyte membrane transport of tryptophan in depression].

The initial rate of L-tryptophan uptake into human red cells as a function of its concentration in the medium was measured in a group of 8 depressed patients hospitalized included 2 bipolar disorders (296.5x, DSM III), 3 major depressions, single episode or recurrent (296.3x and 296.2x, DSM III) and 3 dysthymic disorders (300.40x, DSM III), which were out of antidepressive treatment, with age ranging from 34 to 64 years compared to a group of 11 healthy volunteers with age ranging from 23 to 54 ans. Kinetic constants were measured at 37 degrees C on red cells incubated with tritiated L-tryptophan and cold L-tryptophan over the concentration range 0.1 to 10 mM. The maximum velocity (Vmax) of the saturable transport is severely lowered in a significant manner in the patients compared to controls (mean +/- s.e.m. = 48.9 +/- 5.5 mumol/l cells/min and 92.0 +/- 14 which represents 47% in decrease). In return, the Michaelis constant is unaffected. The linear component of tryptophan transport, which corresponds to the participation of nonspecific transport systems, is not modified. The possible incidence of such a deficit in the plasmatic reserve of tryptophan in depressed patients on the central availability of serotonin synthesis precursor is postulated.

Adult↗
PubMedDate not supplied

[Flunitrazepam and memory (author's transl)].

This work is based on the observation of memory troubles before sleep in patients with sleep problems treated with flunitrazepam. Eight subjects are tested in two sessions, flunitrazepam and placebo, in double blind, with memory tests given the evening after medication and controlled the next morning. One additional test is controlling vigilance. The results show that memory is significantly disturbed by flunitrazepam, both for direct and delayed memory, the next day. On the contrary, recognition is not altered, neither vigilance.

Adult↗
PubMedDate not supplied

[Binding of tritiated imipramine to human platelets. 1 or several binding sites?].

Using Langers' method (10) under their laboratory conditions, the authors determined the characteristics of the high-affinity imipramine-binding site on human platelets in thirty-five normal subjects, equally divided between the sexes and distributed by decade from twenty to sixty years of age and above. Bmax was 440 +/- 121 fmol./mg. protein, Kd 0.96 +/- 0.62, 10(-9) M. Protein concentration was held within a range of 0.2 to 0.55 mg./ml. in order to avoid nonlinear bias with Bmax, expressed in fmol./ml. of incubate. The characteristics of the site did not co-vary with sex or age in this experimental series. However, subject to additional investigation, the curve of the Scatchard graph would seem to indicate the possible existence of a distinct, low-affinity imipramine-binding site.

Adult↗
PubMedDate not supplied

[Efficacy of antidepressants selected as a function of erythrocyte membrane transport and plasma levels of L-tyrosine and L-tryptophan].

The present study concerned 69 depressed patients (26 men, 43 women). The antidepressant drug was prescribed in accordance with perturbations of tyrosine and tryptophan membrane transports (MT) across the red cell, measured in vitro after a wash-out period of ten days. After two to four months of treatment, the clinical results were divided into two groups: normal mood (AMDP - Depression Scale less than 6) and no recovery (AMDP - Depression Scale greater than 6). The initial criteria (e.g. MT) was completed by using plasma tyrosine, tryptophan and the product MT by plasma level. Indeed, the success of this treatment was corresponding to precise abnormalities of variable: (i) tyrosine and tryptophan values for imipramine, (ii) tyrosine values, plasma tryptophan and tryptophan product for desipramine, (iii) tryptophan variables and plasma tyrosine for fluvoxamine (and indalpine). The analysis of clinical failures permitted to complete our previous choice of antidepressant drug.

Adult↗
PubMedDate not supplied

[Joint evolution of erythrocyte membrane transport of tyrosine and tryptophan as a function of the clinical course of depression].

The clinical state and the erythrocyte membrane transports of tyrosine and tryptophan were studied longitudinally during one year (minimum period of 3 months) in 44 depressive patients, 21 men and 23 women of 30 to 77 years of age. According to the DSM III, 18 patients had bipolar disorders (8 with short cycles), 14 had recurrent major depressions and 12 dysthymic disorders. Abnormal values for the membrane transports are found in the majority of patients; the pattern of these abnormalities differs among the nosological groups but decreased ratio of the tyrosine to tryptophan is the predominant finding. The membrane transports normalize as the clinical status improves. In bipolar disorders, the changes observed at the time of switching into mania differ among short and long cyclers. Short cyclers who become manic generally present a short period of normal mood and show values of membrane transports higher than when depressed or euthymic and higher than those of normal controls. Long cyclers directly switch into mania, and when manic have the same ratio of tyrosine to tryptophan than when depressed. Based on these biochemical observations, long cyclers resemble patients with recurrent major depression and short cyclers resemble dysthymic disorder patients, a group for which it has been suggested that one fifth become bipolar within years of evolution.

Adult↗
PubMedDate not supplied

[Neuropsychological functioning of hebephrenic patients. Study of the relationship between visual and manual functional systems].

Relations between visual and manual responses after prismatically displaced vision are studied in 15 schizophrenics and 15 normals. Results show that the changes in visual and manual responses are concordant in normals, whereas the responses of these two modalities are dissociated in schizophrenics. This suggests that the information processing in schizophrenia might be deficient not only at the level of interhemispheric connections, but also in intra-hemispheric functioning. These results cannot be explained by the generally accepted hypothesis of a dysfunction localised in a single hemisphere.

Adult↗
PubMedDate not supplied

[Relationship between blood catecholaminergic variables in depressive patients and normal subjects].

Some biochemical assays are available to test the central NA activity in depressed patients. In several laboratories, two metabolites of NA, namely DHPG and MHPG, in either free, conjugated or total form, have been assayed indifferently for this purpose. The present report shows positive correlations between the level of the two glycols, as well as between their different forms in the plasma. In contrast, the level of erythrocyte COMT activity was not correlated with plasma MHPG, and did not show any change during the treatment with respect to the control pretreatment period in depressed patients. The values of MHPG showed a bimodal distribution in the patients before treatment; the plasma level of this metabolite decreased significantly in the first month of treatment, but did not change subsequently. The COMT activity values, as well as MHPG, were significantly correlated between the different time points, that is the control period and after 1 to 3 months of treatment.

Adult↗
PubMedDate not supplied

[Erythrocyte membrane transport and plasma levels of tyrosine and tryptophan in depression].

L-Tyrosine and L-Tryptophan were studied in 80 depressed patients, hospitalised in Genova and Marseille. After a washout period of ten days, the erythrocyte membrane transports (MT) of L-Tyrosine and L-Tryptophan were measured, as well as their plasma levels; plasma phenylalanine was moreover measured. 33 normal subjects served as control group. In the whole population of patients, the mean of MT's was different compared to controls (MT tyrosine low and MT tryptophan high) and the plasma tyrosine was low. The perturbations of these variables were different according to diagnostic groups (DSM III): MT tyrosine, plasma tyrosine and tryptophan low in bipolar disorders depressed; MT tyrosine low, MT tryptophan high, plasma tryptophan low in major depressions; MT tryptophan high in dysthymic disorders. Phenylalanine was in the normal range compared to controls. The perturbations of MT's involved the part incubated at 37 degrees C for tyrosine, e.g. the facilitated diffusion, and the part incubated at 0 degrees C for tryptophan, e.g. probably the passive and facilitated diffusion. These results were in agreement with the monoaminergic hypothesis of affective disorders and might provide a useful peripheral model.

Adult↗
PubMedDate not supplied

[Erythrocyte membrane transport of L-tyrosine and L-tryptophan in 66 patients with depressive syndromes. Preliminary results].

The transport of Tyrosine and Tryptophan by the membrane of red blood cells has been studied in a group of 66 depressed patients (DSM-III: 27 major depressions, single episode or recurrent; 17 bipolar disorders, depressed; 22 dysthymic disorders). Anomalies were observed: tyrosine transport was decreased in the bipolar disorders and in the major depressions; tryptophan transport was increased in the major depressions and in the dysthymic disorders. These results suggest that membrane transports are disturbed in depressed syndromes, and may be related to dysfunction in the monoaminergic balance.

Adult↗
PubMedDate not supplied

[Choice of antidepressive agents as a function of membrane transport (erythrocytes) of monoamine precursors (L-tyrosine and L-tryptophan)].

In a group of 66 depressed patients, the choice of the antidepressant drug was based upon the result of tyrosine and tryptophan uptake by the membrane of red blood cells. After one month of treatment, 56 subjects were improved, that is 85% of the cases. This result is discussed in comparison with the percentage of improvement described in the literature.

Antidepressive Agents↗