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M Vallet

Publications and source records attributed to M Vallet.

22 records · Page 2Linked to original sources
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GM and KM immunoglobulin allotypes in a Spanish Pyrenean population: Val d'Aran.

Four hundred and thirteen unrelated individuals (202 autochthonous and 211 non-autochthonous) of Val d'Aran (Catalan Pyrenees) have been analysed for the GM and KM immunoglobulin genetic system using the inhibition haemagglutination method. This population was defined by eight GM haplotypes (GM*3 23 5*, GM*3 5*, GM*1,17 21,28, GM*1,2,17 21,28, GM*1,17 5*, GM*1,17 5,6,11,24, GM*1,17 10,11,13,15 and GM*1,17 10,11,13,15,16) inferred from the 17 observed phenotypes. The Val d'Aran population frequencies conform to Hardy-Weinberg expectations. The frequencies of phenotypes and haplotypes show a definite homogeneity between the autochthonous and non-autochthonous people of Val d'Aran and 11 other Pyrenean populations (Mauléon, Macaye, St. Jean Pied de Port, Vallée de L'Ouzom, Gavarnie, Barèges, Luz St. Sauveur, Esparros, Camurac, Capcir and Pays de Sault) that have already been studied for the same allotypes. A factorial correspondence analysis was performed for the 12 autochthonous Pyrenean populations, showing a high frequency of the GM*3 23 5* haplotype in the three Pyrenean regions (Western, Central and Eastern), while the GM*1,17 21,28 haplotype is mainly found in the Central region, GM*3 5* in the Eastern and Western zones, and the GM*1,2,17 21,28 is mainly present in the Central and Eastern populations. The results show a relative regional homogeneity, so there is no evidence of a frequency gradient in the Pyrenean populations for the GM and KM genetic systems. It may, however, be noticed that the Central Pyrenean populations form a group, with one population (Vallée de l'Ouzom) isolated from the rest, probably because of its particular model of inheritance by which the heritage is passed to the first born without sex consideration. It has been possible to point out some differences in the genetic structure of the autochthonous and non-autochthonous Val d'Aran population and to place the autochthonous Aranese group among its Pyrenean neighbours.

Ethnicity↗
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[P300 and neuropsychological tests in schizophrenia and bipolar patients].

INTRODUCTION: A smaller P300 amplitude has been found in schizophrenic patients in the majority of the studies done. And this occur in spite of treatment, sex, clinical stage and evolution time of the illness. It has been already described an association between this amplitude reduction and a poor result on the neuropsychological tests. But these changes in the P300 amplitude are not specific of the schizophrenic patients and they can be found in affective patients. OBJECTIVES: This study try to value the influence of the clinical stage and the cognitive results on the P300 values in the bipolar patients and to compare these results with the schizophrenic patients. PATIENTS AND METHODS: It has been evaluated the evoked potentials and the results of a neuropsychological battery of tests in three patient groups: schizophrenics in patients with acute symptomatology (n = 18), schizophrenic out patients without acute symptomatology (n = 15) and bipolar in patients during a maniac period (n = 16). RESULTS: It has not been found any differences between schizophrenic and maniac patients nor in the amplitude or in the latency of the P300. The results of the neuropsychological tests have not any relation with P300 amplitude and latency except for the verbal fluidity (VF) which has a good correlation with a longer P300 latency. At the same time this was the only test in which schizophrenic patients have smaller results than affective patients with a good correlation. CONCLUSIONS: These results suggest a similar pattern of neuropsychological and neurophysiological damage in schizophrenic and affective patients in acute period of mania.

Adult↗
PubMedDate not supplied

[The electroretinogram and visual evoked potentials in patients with Parkinson's disease].

Whether Parkinson's disease patients have been shown to have abnormal visual evoked cortical potentials (VEPs) to flash and pattern stimulation or not, is a matter widely discussed. Actually it is said that this variability may be due to the stimulus method used and how the patients were selected. The retina is rich in dopamine and together with previous animal and human studies, this suggests that the abnormal VEPs in Parkinson's disease patients may be due to a biochemical and electrophysiological disorder in the retina. This hypothesis has been examined by studying the flash VEPs, pattern VEPs and with light electroretinogram in 29 Parkinson's disease patients and matched control subjects. We have found: a) Slower FVEPs and PEVPs latencies in Parkinson disease patients. Flash VEPS were more frequently abnormal than pattern VEPs. We have only found a significant relationship between slow flash VEPs and the patient age. b) Electroretinograms waves (a) and (b) amplitudes were smaller in Parkinson disease patients than in control subjects. b/a coefficient abnormal values must be due basically to wave (a) alterations. These values are statistically significant with respect to the number of years of L-Dopa in the evaluative stage and the evolutive stage of the illness. For all these reasons, we can deduce that an anomaly exists in the dopaminergic pathway in the retina, localized in the plexiform layer and neurophysiologically detectable by a study of the wave variations of the ERG and of the b/a coefficient.

Adult↗