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M Petit

Publications and source records attributed to M Petit.

At least 55 records · Page 3Linked to original sources
PubMed1998

Plasma 3-methoxy-4-hydroxyphenylglycol and homovanillic acid measurements in deficit and nondeficit forms of schizophrenia.

BACKGROUND: Discrepancies in the biochemical research on negative symptoms in schizophrenia may be ascribed to the lack of differentiation into primary and secondary negative symptoms. We have used Carpenter's criteria to define the deficit syndrome of schizophrenia as the presence of enduring and primary negative symptoms and measured catecholaminergic parameters in deficit as compared with nondeficit schizophrenics. METHODS: We have investigated plasma homovanillic acid (pHVA) and 3-methoxy-4-hydroxyphenylglycol (pMHPG) concentrations in 34 DSM-III-R neuroleptic-treated schizophrenic patients who were classified into deficit (n = 14) and nondeficit (n = 20) forms of schizophrenia. All these patients were in a stable clinical and therapeutic status for the preceding 12 months. RESULTS: The 14 deficit schizophrenic patients had lower plasma levels of pHVA and higher plasma concentrations of pMHPG from 9 AM to 12 AM as compared with the 20 nondeficit schizophrenic patients. The two groups did not differ on any demographic, therapeutic, or clinical variable considered. CONCLUSIONS: Our data are consistent with the postulated distinct pathophysiological basis for the deficit syndrome of schizophrenia and suggest that opposite alterations in the pHVA or pMHPG levels may reflect specific changes in noradrenergic and dopaminergic functions in these deficit patients.

Aged↗
PubMed1998

How readily will sheep walk for a preferred forage?

We studied how ewes chose between a poor-quality hay freely available and a good-quality one offered in limited quantities when they walked across an indoor test area. To determine what dictates a ewe's behavior, we varied the accessibility of the good hay by changing the quantity that rewarded the walk (2, 4, 8, 16, or 32 g) and the distance walked (23 or 46 m). Ewes were more reluctant to walk for the good hay as reward level decreased. For a given reward, average preference for good hay (P(GH)) also fell when ewes had to walk 46 m to be rewarded. In each comparison, for the same reward to distance (Rew/Dist) ratio, average P(GH) did not differ. We determined the correlation between P(GH) and Rew/Dist using data from three experiments with ewes offered a similar choice. The best model accounted for 85% of the corrected total sum of squares. Good hay procurement cost thus dictated a ewe's behavior. Choice was suboptimal only, either due to the test conditions, discrimination errors, or an animal's will to select a mixed diet. Our results suggest that, within its perceptive field, a ewe will equally walk to resources that have the same edible biomass relative to the distance to the patch.

Animal Feed↗
PubMed1998

[Survival and quality of life of patients with testicular cancer].

Cisplatin has revolutionized the prognosis of testicular cancers. Stage I non-seminomatous germ cell tumours can be cured in 98% of cases; adjuvant therapy, chemotherapy or lymph node dissection, is recommended in high-risk tumours, while surveillance is indicated in tumours with a low risk of recurrence. Good prognosis metastatic non-seminomatous germ cell tumours are cured in almost 80% of cases at the cost of well tolerated chemotherapy, 3 BEP or 4 EP. The morbidity of lymph node dissection has been markedly decreased by means of various techniques of preservation of all or part of the sympathetic and lumbar contingent. Resection of residual masses after chemotherapy for metastatic non-seminomatous germ cell tumours is still recommended in the majority of cases. Stage I seminomatous germ cell tumours are cured in 98% of cases by 25 Grays of lumbo-aortic radiotherapy. Screening for carcinoma in situ in the contralateral testis to the primary tumour is controversial, but is recommended in the case of lowering of a maldesended testis after the age of puberty. Future paternity is a major concern in tumours of young adults, most of which are cured.

Adult↗
PubMed1997

Association of DNA polymorphism in the first intron of the tyrosine hydroxylase gene with disturbances of the catecholaminergic system in schizophrenia.

We examined whether there are clinical or biological differences in chronic schizophrenic patients sharing a rare variant allele (a perfect ten tetranucleotide repeats allele of the human TH01 microsatellite) in the tyrosine hydroxylase (TH) gene. For that purpose, clinical parameters (PANSS subscores) and plasma measurements (homovanillic acid and 3-methoxy-4-hydroxy-phenylglycol (MHPG)) were analyzed in five schizophrenic patients sharing the rare allele and 19 schizophrenic patients who did not possess this allele. The mean concentration of plasma HVA and plasma MHPG were significantly lower in the group of schizophrenic patients sharing the rare allele. No other group differences were observed between both groups. These results suggest that this TH gene polymorphism may be associated with disturbances of the catecholaminergic pathway.

Adult↗
PubMed1997

Morphologic characteristics of the fossa ovalis as an anatomic basis for transseptal catheterization.

Interest in transseptal catheterization has increased in recent decades, due to the fact that the technique has acquired a degree of security similar to other procedures. For a correct transseptal catheterization technique, it is essential to know the exact location of the fossa ovalis, its points of reference, and those morphologic parameters which allow us to assume precisely its dimensions. For this purpose, 97 human fresh hearts were studied (age range: 17-94 years; mean 63.74 +/- 18.50, 62 (64%) men and 35 (36%) women). The major and minor diameters of the fossa ovalis and the thickness of the intervenous tubercle were measured. In 22% of the cases, the fossa ovalis was permeable. Correlative tests between morphologic and general parameters were made. A positive correlation between cardiac weight and fossa ovalis area, and cardiac weight and thickness of the anterior limbus of the fossa was obtained.

Adolescent↗
PubMed1997

[Coronary perfusion: a classification based on the type and relative extension of coronary irrigation (II). An angiographic algorithm].

INTRODUCTION AND OBJECTIVES: An angiographic algorithm of clinical utility, applicable to conventional coronariography, is proposed to establish different patterns of coronary distribution depending on the characteristics of the myocardial perfusion, considering the starting point as the segmentary classification of the arterial irrigation of the left ventricle. METHODS: To validate this system of classification, 30 hearts coming from necropsy were studied, through anatomical and angiographical analysis. The average age of the population studied was of 69.8 +/- 14.6 years. The range was between 26 and 91 years. To study them, the hearts were unrolled and after a coronariography and a dissection of the coronary arterial tree, the identification of the perfusion mode--exclusive or shared--of every left ventricle segment was done. Then an algorithm based on the type of division of the left main branch, and on the type of perfusion of the left ventricle inferobasal segment was applied to the angiographic frames. There was statistical analysis of the data obtained in the anatomic and angiographic studies. To verify the applicability of the algorithm, it was employed to successive series of 100 coronariographies in vivo, and these were then compared to the results obtained with the necropsy series. RESULTS: The statistical comparison between the percentages of the classification obtained from both analyses of the necropsy series showed no significant differences. The statistical comparison of the percentages of the classification obtained between the in vivo and post-mortem analyses did not show any significant difference either. CONCLUSIONS: The angiographical algorithm developed allows to classify the myocardial perfusion of the left ventricle, by the conventional coronary arteriography, in three groups of clinical interest. The classification is based on the predominance of the left ventricular segments exclusively irrigated by: the anterior interventricular artery (type I), the circumflex artery (type II), or a balance between both arteries (type III). The angiographic projections in left anterior oblique with caudal angulation and right anterior oblique are important for its application. The classification of the ventricular perfusion established with the developed algorithm can be validated as being equivalent to the one obtained through the anatomical series.

Adult↗
PubMed1997

Simulation of large-scale tropical tuna movements in relation with daily remote sensing data: the artificial life approach.

Tunas are known to be able to travel long distances. The aim of this paper is to propose new ethological models which reproduce some tuna movements using the dynamics of their environment. We use sea surface temperature animations (from remote sensing data) to model the South West Indian Ocean, and French purse seiners data are used to estimate movements of fish. The objective of the models will be to find a northern movement from the Mozambique Channel to the Seychelles Islands at the appropriate time (May-July). The initial model uses our ecological knowledge of tunas, i.e. the search behavior for high concentrations of food commonly associated with thermal fronts. In some cases, this simple model creates some northern movements from the Mozambique Channel, but it cannot be used to reproduce large-scale movements between the Mozambique Channel and the Seychelles Islands. The next generation model is created where tuna behaviors are modeled by an artificial neural network, using a genetic algorithm to adjust the connection weights. The tuna school-network receives daily information from its local environment and chooses the best actions in order to be able to pass from the Mozambique Channel to the Seychelles Islands at the appropriate time. One neural network emerges and represents an adaptive behavior able to interpret daily sea surface temperatures to mimic large-scale tuna movements. This artificial behavior can be generalized to each possible departure position from the Mozambique Channel. This modelling represents a new tool to study large-scale movements of pelagic fish, and is a first step towards real-time management of fisheries.

Algorithms↗
PubMed1997

Detection of two new polymorphic sites in the human interleukin-1 beta gene: lack of association with schizophrenia in a French population.

The pathogenesis of schizophrenia might involve abnormal development of the human brain. Interleukin-1 beta is a cytokine implicated in the development of the central nervous system and therefore its gene is a candidate gene in schizophrenia. Polymorphisms within the coding sequence and the 3'UTR of the IL1 beta gene were searched for using PCR-SSCP. Two polymorphisms, 1B-175/1B-173 and 1B-1765/1B-1763 were found in addition to the previously published TaqI site. Furthermore, a mutant was found in codon 106 (exon 5) of the IL1 beta gene located next to the published polymorphism at the TaqI site and abolishing this site. This novel mutation encodes an Asp in place of an Asn and was only observed in one patient in our French population. Association studies were conducted with the polymorphisms 1B-175/1B-173 and TaqI. There was no allelic or genotypic association between either of the two polymorphisms and schizophrenia. In our population, there is no evidence that the IL1 beta gene is involved in schizophrenia.

Adult↗
PubMed1997

The deficit syndrome of schizophrenia: towards heterogeneity.

Since the turn of the century, psychiatrists have been concerned with both the unity and diversity of schizophrenia. From these early descriptions until now, many authors have attempted to delineate clinically meaningful subtypes within this disorder. In this connection, negative/positive subtyping has generated great interest. Carpenter and his team have emphasized the origin of the negative symptoms observed. They have proposed that primary enduring negative symptoms should be distinguished from transient negative symptoms resulting from treatment, depression or social deprivation and should be termed deficit symptoms. The validity of this subtyping is supported by clinical, biochemical or electrophysiological studies showing differences between deficit and nondeficit patients.

Adult↗
PubMed1996

Association study between schizophrenia and monoamine oxidase A and B DNA polymorphisms.

Monoamine oxidases (MAO) A and B, which are encoded by two distinct genes located on the human X chromosome, are both involved in the oxidative metabolism of dopamine. Decreased levels of platelet MAO-B activity has been reported in patients with schizophrenia and genetic variation in MAO activity had been proposed as a significant factor in the etiology of this disease. We carried out an association study using two intragenic polymorphisms within the MAO-A and MAO-B genes in 110 schizophrenic patients and 87 control subjects. For each polymorphic marker, no significant difference in allelic frequencies was observed between patients and controls. Nevertheless, a trend toward an association between allele 1 of the MAO-B gene and paranoid schizophrenia was found. Our results do not support the hypothesis that inherited variants of MAO genes might play a major role in a genetic predisposition to schizophrenia. Since several previous reports found a low MAO-B platelet activity in patients with paranoid schizophrenia, the identification of polymorphisms related to enzyme activity would be useful.

Adolescent↗
PubMed1996

Difference between guinea pig and rat in the liver peroxisomal response to equivalent plasmatic level of ciprofibrate.

Guinea pig was previously classified as a species nonresponsive to peroxisome proliferators. However, none of the previous reports was based on pharmacokinetic data. Here, after a comparative pharmacokinetic study between the guinea pig and rat, we evaluate the guinea pig liver peroxisomal response to ciprofibrate, a hypolipemic agent and a potent peroxisome proliferator in rat. (1) Pharmacokinetic results show equivalent in guinea pig and rat when guinea pigs are treated with ciprofibrate at 30 mg/kg twice a day and rats are treated at 3 mg/kg once a day. (2) The treatment of guinea pigs at 30 mg/kg twice a day for 2 weeks leads to a significant increase in the liver peroxisomal palmitoyl-CoA oxidase activity (x 1.6) and also in the microsomal omega-laurate hydroxylase activity (x 1.8). These increases are in accordance with the changes in polypeptide patterns of isolated liver peroxisomes as well as in the immunoblotting of acyl-CoA oxidase. It is deduced that a weak, but significant, peroxisome proliferation can occur in guinea pig liver after a ciprofibrate treatment at dosages corresponding to equivalent plasmic concentrations of the drug between guinea pig and rat. (3) The hybridization of guinea pig liver RNA with the rat liver-inducible acyl-CoA oxidase cDNA probe shows a decrease in the corresponding heterologous mRNA content after treatment with ciprofibrate at 30 mg/kg twice a day. This result contrasts with the slight increase observed in immunodetection and in enzymatic assays, suggesting the existence of at least two different acyl-CoA oxidases in guinea pig liver peroxisomes.

Acyl-CoA Oxidase↗
PubMed1996

Identifying subtypes of schizophrenia by cluster analyses.

The existence of two subtypes of schizophrenia (positive and negative) is well established. The evidence in favor of other subtypes, particularly a disorganized subtype, is still the subject of some debate. The aim of the study reported in this article is to investigate the possibility of further subtypes of schizophrenia by applying a particular method of cluster analysis to a particular set of data. Ward's method of cluster analysis was applied to the Positive and Negative syndrome Scale (PANSS) scores of 138 patients, defined as having schizophrenia by one of four diagnostic criteria. The validity of the cluster solution was assessed both by examining differences between clusters on a number of clinical characteristics recorded for each patient and by comparing the results obtained from the PANSS with those derived from a cluster analysis using two other instruments (the Scale for the Assessment of Negative Symptoms and the Scale for the Assessment of Positive Symptoms). Results from the cluster analysis suggest the existence of at least four subtypes of schizophrenia: positive, negative, mixed, and disorganized. A fifth subtype includes patients with few symptoms, suggesting the simple schizophrenia named by Bleuler. Evidence for the validity of these subtypes was provided by the differences observed between the clusters on a number of clinical characteristics and by the similarity of the cluster solution obtained from the different instruments. In conclusion, the negative-positive dichotomy in schizophrenia is an oversimplification, and the existence of a more complex structure needs to be taken into account in future research.

Adult↗
PubMed1996

[Deficit: the value and difficulty of defining the primary or secondary character of observed symptoms].

Since early descriptions of schizophrenia, heterogeneousness of clinical forms is one of the most typical figure of the disease. Nowadays authors perceived the necessity for patients to gather in groups in the most homogeneous way. First, different clinical effects have been noticed among schizophrenic patients with neuroleptics in function of their type or their dose. Then dichotomic concepts between positive and negative forms of schizophrenia succeeded one another. Several scales for negative symptoms of schizophrenia have been used to test the antideficit effect of different doses of neuroleptic agents. But these punctual evaluations cannot confirm primary nature of these symptoms, not derived from positive, depressive, anxious symptoms or secondary symptoms of neuroleptic treatment (as akinesia). Carpenter et al. defined the concept of deficit syndrome in schizophrenia, which can be evaluated with the SDS (Schedule for the Deficit Syndrome, Kirkpatrick et al., 1989). This classification of patients showed certain particularities: clinical, neurologic and biological ones, which seemed to confirm the initial hypothesis of homogeneousness of deficit syndrome in schizophrenia. The relevance of this concept forecasts a very promising future to research in the area of schizophrenia, with therapeutic and evolutive implications.

Akathisia, Drug-Induced↗
PubMed1996

A comparison of an atypical and typical antipsychotic, zotepine versus haloperidol in patients with acute exacerbation of schizophrenia: a parallel-group double-blind trial.

The atypical antipsychotic zotepine was compared to haloperidol in 126 patients suffering from acute exacerbation of schizophrenia (DSM-III-R) in a randomized, double-blind study. After 8-weeks, 150 to 300 mg zotepine improved scores on the Brief Psychiatric Rating Scale (BPRS) more than 10 to 20 mg haloperidol (-17.03 versus -13.45; 95%CI for zotepine-haloperidol -9.34/2.04). BPRS subscores and Clinical Global impressions (CGI) Severity and improvement subscales showed comparable gains, but scores on the Scale for the Assessment of Negative Symptoms (SANS) improved significantly more with zotepine (-23.82) than haloperidol (-15.15; P < .05; 95%CI for zotepine haloperidol -18.03/-0.18). Adverse events were reported by 71 percent of zotepine and 78 percent of haloperidol patients. Extrapyramidal side effect (EPMS) scores decreased with zotepine (-0.34) but increased with haloperidol (+2.32; P < .05). Seven haloperidol patients reported akathisia but no zotepine patients did (p < .05). Uric acid reductions (which appear to have no clinical consequence) and transient raised liver enzymes were recorded with zotepine. Weight increased on zotepine (2.32 kg; P < .001) and a small increase in pulse rate occurred (P < .05). Both drugs were effective in reducing positive symptoms of schizophrenia; zotepine was significantly more effective against negative symptoms and reduced EPMS.

Adult↗
PubMed1996

[Coronary perfusion: classification based on the type and relative extension of coronary irrigation. Morphologic determinants].

INTRODUCTION AND OBJECTIVES: This work attempts to systematize the arterial segmentary distribution of the left ventricle and confirm the existence of coronary irrigation patterns, and determine the principals for the clinical application for diagnosis or therapeutics, using as the starting point, Selvester's classification of the arterial irrigation of the left ventricle. METHODS: Ninety human heart specimens from autopsies were studied. The average age of the sample was 61.09 +/- 21.96 years. The range was between 4 days and 94 years old. The coronary artery tree was dissected, and each artery responsible for the irrigation of each of the twelve left ventricle segments was identified. The percentage of the muscular mass, of each segment in which the left ventricle had been divided, irrigated by each coronary artery, was obtained. RESULTS: The analysis of the 12 segments of the left ventricle show that the three septal segments (basal, mesial and apical) present a type of irrigation which is practically constant and of a shared type. The superoapical, posterobasal and posteromesial segments present an irrigation with a high index of exclusivity for the anterior interventricular and circumflex arteries. In the rest of the segments the vascularization is of a mixed type, although the apical segments reach an important degree of arterial exclusivity. CONCLUSIONS: The relative number of ventricular segments, exclusively irrigated by the interventricular and circumflex arteries, makes it possible to describe three groups of arterial irrigation (I, II, III), and each of them, in two subgroups (A, and B) depending on the percentage of ventricular segments irrigated in an exclusive or shared mode, by the interventricular or circumflex arteries.

Adolescent↗