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Biomedical subjects

R Tissot

Publications and source records attributed to R Tissot.

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

[Some aspects of cognitive activities in schizophrenic patient (author's transl)].

Nine paranoid schizophrenics, five control subjects of the same age and four hebephrenic schizophrenics were examined using Piaget's genetic psychology tests. The study of assimilation/accommodation equilibrium in the cognitive activities of schizophrenic patients confirmed our previous results which primarily dealt with hebephrenic patients [12]. The thinking of paranoid schizophrenics is dominated by increased assimilation which explains their tendency to deform observables and their difficulty in generalising reasoning. The assimilation/accommodation equilibrium of their logical operations is affected resulting in: a) difficulty in formulating reflecting abstractions and therefore the comprehension and extension of concepts; b) loss the feeling for logical necessity and a tendency to utilize magical thinking and subjective explanations.

Adult↗
PubMed1980

Aspects of cognitive activity in schizophrenia.

The application of Piaget's genetic psychology tests to schizophrenic patients yielded the following findings. The intelligence quotient of schizophrenics, although within the normal range, is slightly lower than that of a control population of similar age. This is due not to a loss of the operations of the intellect, but to a difficulty experienced by the patients in actualizing the operations. The difficulty is seen particularity in operations dealing with specific objects which require a constant maintenance of the equilibrium between assimilation and accommodation. The thought processes of hebephrenic patients oscillate between excessive assimilation, resulting in distortion of observable data, and excessive accommodation which by adhering to the observable data distorts the reasoning processing. The thought processes of paranoid schizophrenics are dominated by excessive assimilation. This predominance explains their tendency to distort observable data and their difficulty in the generalization of reasoning; it also has an impact on the assimilation/accommodation equilibrium of thier logical operations, leading to (a) difficulties in delimiting reflecting abstractions, and therefore the comprehension and extension of concepts, and (b) loss of proof based on logico-mathematical reasoning and, as a result, a propensity to resort to magical thinking and subjective explanations.

Cognition↗
PubMed1980

[Opiate receptors and sleep. Effects of microinjections of morphine in the median thalamus and the periaqueductal gray matter of the rabbit (author's transl)].

Microinjections of morphine in optimal doses into the medial thalamus (40 micrograms) and periaqueductal gray matter (10-20 micrograms) produce slow-wave sleep with abondant spindles, in addition to analgesia. Like analgesia, the sleep-inducing effect is blocked by naloxone (1 mg/kg i.v., 160 micrograms i.c.). One may therefore conclude that the effect is related to the agonistic action of morphine on endorphine receptors. It is thus probable that the endorphins constitute a regulatory system acting on the medullary-thalamic sleep-inducing structures which generate the sleep spindles. At higher dose levels, injections of morphine into the same structures produce behavioral agitation resembling the dissociated REM sleep described by Jouvet and which is not blocked by naloxone. The agitation might be due to an indirect action of morphine, and therefore of endorphin receptors, acting on monoaminergic structures.

Animals↗
PubMed1980

[The morphology of substance P in the human brain as determined by an immuno-histo-fluorescence study].

The application of Coon's indirect method, using antisubstance P antibodies, has permitted the immuno-histo-fluorescence study of the distribution of SP positive structures in 6 human brains. Several areas of the hemispheres and of the brainstem have shown axons of various sizes and densities exhibiting SP positive varicosities. Their topographic distribution was established for the human brain and compared with the distribution observed in the brain of the rat. Both distributions appeared very similar in the somato-sensorial systems of the spinal cord, medulla and pons, in the structures of the midbrain tectum and tegmentum as well as in those of the thalamus and hypothalamus. Substantia nigra and globus pallidus showed a large amount of substance P, in human brain as well as in the rat, but in human brain, substance P positive axons were arranged in a longitudinal peridendritic "pipe" shaped manner, particularly in the antero-external and superior part of the substantia nigra as well as in the internal segment of the globus pallidus; such "pipes" were rarely seen in the rat. Moreover, in man, the pallidal substance P was almost exclusively seen in the internal segment while it spreads to the external segment in the rat. Substance P was found to be scarce in the rhinencephalic and limbic structures, the amygdala and the olfactory bulb of man, contrary to their abundance in the rat, but this peculiarity could be due more to some pathological changes associated with the advanced age of the patients whose brains were studied than to an interspecific difference.

Aged↗
PubMed1980

[Choice of symptoms in neuroses. Hysterical and obsessive-phobic neuroses].

This publication is a first attempt to verify our hypothesis that symptom choice in the classical neuroses depends on a disequilibrium between assimilation and accommodation, in the Piagetian sense, of reflective thinking. Results of tests derived from classical paradoxes of Western thought, from genetic psychology and from a neuropsychological test of the habituation of the alpha-blocking response support the following hypothesis; the reflective thinking of hysterical patients appears dominated by a primacy of assimilation and that of obsessional patients by a primacy of accommodation.

Alpha Rhythm↗
PubMed1979

Blood-brain movements of tryptophan and tyrosine in manic-depressive illness and schizophrenia.

In order to investigate possible disturbances of the blood-brain transport mechanisms of monoamine precursors in manic-depressive illness and schizophrenia, we have measured the brain arterio-venous difference of DOPA, or 5-HTP, or tyrosine and tryptophan in 36 patients, during the infusion of either L-DOPA or L-5-HTP. The infusion lasted for 30 min, and blood was sampled during and immediately after the infusion, simultaneously in the femoral artery, the jugular vein and a vein of the arm. During the infusion of L-DOPA, manic patients have a higher extraction of L-DOPA than depressive patients and controls. During the infusion of L-5-HTP, pdpressive patients have a higher brain extraction of 5-HTP than manic or schizophrenic patients. In depressive patients, a small uptake of tryptophan correlated with a large outflow of tyrosine was observed. The opposite was seen in manic patients, with an outflow of tryptophan correlated with an uptake of tyrosine. In schizophrenics, there was an outflow of tryptophan and random variations of tyrosine. These brain arterio-venous differences were not correlated with arterio-venous differences for peripheral tissues. Taken together, these results are compatible with a disturbance of the blood-brain transport of amino acids precursors of monoamines in manic-depressive illness and schizophrenia.

Adult↗
PubMed1979

[Senile plaques, neuro-fibrillar degeneration and other associated cerebral lesions (morphology and pathogenetic theory].

A brief review about present knowledge on morphology of brain degenerative alterations in the elderly, their topography, their correlations and the various pathogenic theories. The particular pathoclisis of some areas is reported, i.e. the pathoclisis of some hippocampal areas for neurofibrillary tangles and senile plaques, the pathoclisis of the IVth layer of calcarinian cortex for dyshoric angiopathia. These morphological pecularities must be correlated to more recent data concerning alterations of neurotransmitters and their enzymes.

Aged↗
PubMed1979

[Mechanisms of action of the antidepressants (author's transl)].

The tricyclic and related antidepressants reduce monoamine uptake at the synapses, block the presynaptic receptors and, after chronic administration, act upon the synthesis of the monoamines and the sensitivity of the post-synaptic receptors. The NA and 5-HT synapses are influenced to different degrees by the antidepressants: for example, desipramine has a preponderance of activity at NA synapses and clomipramine at 5-HT synapses. By combining these findings and by highlighting one or other of these properties, it is possible to come to diametrically opposite conclusions upon the effect of the antidepressants upon monoamine performance (activation or inhibition) and to develop many models of the mechanisms of antidepressant action. The authors describe some of these and stress the model which is at the basis of the studies being carried out at the Department of Psychiatry of the University of Geneva.

Animals↗
PubMed1979

[Physiopathology of endogenous psychoses].

Metabolic theories of manic-depressive psychosis and schizophrenia are reviewed and constructivist models are presented which attempt to integrate biochemical, neurophysiological and clinical findings.

Antidepressive Agents↗
PubMed1979

[Several aspects of programming errors in the frontal syndrome].

In order to study different aspects of programming impairment, 32 patients with frontal lesions and other pathological groups were given two tasks: (a) "REY's Complex Figure" the results of which were compared to those of other graphic tasks; (b) an alternation task. The results of the first task indicate that the frontal subjects show characteristic disturbances, which are described. These patients encountered specific difficulties in the second task when the rule to be found involves asymmetrical sequences. The relationship between the different tasks and the programming impairment is discussed.

Brain Damage, Chronic↗
PubMed1978

The hemopexin locus: its assignment to linkage group I in the laboratory rabbit (Oryctolagus cuniculus) and evidence for a fourth allele.

The hemopexin locus phenotypes were determined for 450 animals with polyacrylamide gel electrophoresis, and the presence of a fourth allele at this locus was revealed. Of the 19 mating types segregating at this locus, 17 demonstrated segregation ratios consistent with the hypothesis of a four allele, codominant, autosomal system. Studies of three of our largest inbreeding lines indicated that fixation at this locus has occurred in two of them. Linkage studies showed that the Hx locus is located between the color locus, c, and the Hq blood group locus; therefore it is assigned to Linkage Group I of the rabbit.

Alleles↗
PubMed1978

[Uptake of tryptophan and tyrosine in some cases of manic depressive psychosis and schizophrenia (author's transl)].

The uptake of tryptophan and tyrosine by the brain has been studied in 6 manic-depressive patients and in 8 schizophrenics. In an attempt to saturate the blood-brain transport mechanisms, this uptake has been evaluated by measuring the arteriovenous differences (arterial plasma-internal jugular plasma) of these two amino acids before and after perfusion with L-dopa and L-5-HTP. Considering a positive difference as an uptake and a negative one as an outflow, results show (1) in melancholia an uptake of tryptophan and an outflow of tyrosine; (2) in mania an uptake of tyrosine and an outflow of tryptophan, and (3) in schizophrenia an outflow of tryptophan accompanied with either an uptake or an outflow of tyrosine. In addition, the kinetics of tryptophan binding to plasma proteins and the ratio of tryptophan/tyrosine uptake are different in manic-depressive illness and in schizophrenia. These results support the view that a disturbance in the blood-brain transport mechanisms of tryptophan and tyrosine could be involved in the physiopathology of manic-depressive illness and schizophrenia.

Bipolar Disorder↗
PubMed1978

[Pallido-dentate calcifications (apropos of 7 anatomo-clinical case reports)].

"Fahr's Disease" is characterized by bilateral and symmetrical calcifications of the Globus Pallidus (systematically extending to the Commisura Anterior and the Capsula Interna, and less commonly to the Putamen, the Centrum Semi-Ovale and the Cerebral Cortex), and of the Cerebellar Nucleus Dentalus (with spreading to the White Matter and the Cortical Lamellae). Lesions or absence of Parathyroids are frequently related, with subsequent metabolic disorders of Phosphorus and Calcium, but idiopathic cases without hypoparathyroid disturbances are also found. A Morgagni-Morel Hyperostosis Frontalis Interna is often associated with "Fahr's Disease", and there could be a relationship between these two affections. We found in three cases the association between "Fahr's Disease" and Morel's Nodular Dysgenesis of the Frontal Cortex. Most of the cases are sporadic, but observations with a clear familial incidence are also found. Clinically, various Neurological Disorders (cerebellar, extrapyramidal, pyramidal, dysarthria, epileptic seizures) are often but not always observed; the Psychiatric Disorders found in some cases could be fortuitious associations (psychoses), connected to hypothyroidism (oligophrenia), and in aged patients, to unrelated cerebral vascular or degenerative lesions; very seldom, a dementing state could be connected to the spreading of calcifications to the Cerebral Cortex.

Aged↗