Répartition transversale des macroinvertébrés benthiques dans un bras du Rhône

While the downstream distribution of benthic macrofauna has been studied in many rivers, its transverse distribution remains rather unknown. The present work concerns this problem in a semi-regulated arm of the Rhône. The characteristics of this arm are: width 80 m, depth 0.5 to 1 m in the section studied, pebble substrate, rocky banks, discharge regulated at 30 m³. s^-1 except for floods up to 1 000 m³. s^-1. The substrate was sampled with a Hess cylinder which collects the fauna present on 0.125 m². Eight stations were located across the river, and 22 samples were collected. Correspondence analysis was applied to the Taxa X Samples matrix, and the results were studied by analysis of inertia, canonical correlation and variance analysis. A close correlation appears between the faunistic structures and the stations. Two main units are revealed. The first one includes a ten meters band along each bank, the other covers the main part of the bed, between these two bands. The two units differ in their taxonomic richness and abundance, many taxa being only present along the banks. A symmetrical gradient of density appears between the channel and the banks. Moreover, the fifth factor of the correspondence analysis reveals that the fauna of one side is not identical to that of the other. The cause of these structures remains uncertain. Among the different parameters, the distance from the banks seems to be the most significant. The existence of a gradient may be due to a dissemination of the fauna from the banks towards the channel. This study suggests the importance of the banks in the dynamics of the benthic fauna of large, fast-flowing rivers, especially in connection with the floods. This must be taken into account when sampling in such rivers.     

Caractérisation de la l-thréo-β-hydroxyleucine à partir de Deutzia gracilis

l-threo-β-Hydroxyleucine has been isolated from Deutzia gracilis by ion-exchange resin chromatography, and by preparative paper chromatography. The substance is reduced to leucine by hydroiodic acid and offers the characteristic reaction of β-hydroxyamino acids with periodic acid. Alkaline decomposition confirms the β position of the alcohol function. The natural substance and the dl-threo-β-hydroxyleucine are inseparable by paper chromatography, and the study of their nuclear-magnetic-resonance spectra brings supplementary arguments in favour of the threo form. The natural substance has the same infrared spectrum as synthetic threo-β-hydroxyleucine.     

Caractères physico-chimiques des choanoleucocytes de quelques Invertébrés

Sans résumé     

De l’origine des anthropoïdes à l’émergence de la famille humaine

The human lineage has a very ancient origin, as most of the mammals. Its oldest representatives, anthropoid primates, have been described from Asia some 45 million years ago. During this long evolutionary story, two critical stages have appeared as especially important, their beginning in Asia and the emergence of hominids in Africa, some seven million years ago. These two stages are discussed hereby with new data relative to their Asian origins and their dispersal into Africa between 45 and 40 million years ago. Following this dispersal event, these primates evolved in Africa and gave rise to the early hominids. These appeared around seven million years ago and have three distinct representatives. Among them, Toumaï appears as the oldest and the closest to our ancestry, a point that is evidenced here.     

Évaluation de la perfusion et de la fonction contractile du myocarde à l’aide de l’analyse de Karhunen-Loeve en tomographie d’émission monophotonique myocardique synchronisée à l’ECG

GoalWe evaluated the diagnostic performance of the Karhunen–Loeve transform applied to myocardial gated SPECT. The previous studies showed that KLT images characterize myocardial perfusion (KL0) and contractile function (KL1).Method and material99mTc-gSPECT studies were performed in 101 patients (121 acquisitions) with suspected or known coronary artery disease. The images were evaluated using a five-point scoring system dividing the left ventricle into 11 segments. We compared the scores obtained by this semi-quantitative visual analysis of gSPECT and KLT images.Results and discussionThe agreement for perfusion and thickening scores was 94 and 95% respectively. Quantitative evaluation of KL0 and KL1 images by univariate and multivariate analysis was performed in the left ventricular ROI. Discriminant analysis characterized the acquisitions as normal or pathologic with a sensitivity of 95% and a specificity of 96% and positive and negative predictive values of 96 and 95%. These selection criteria were tested prospectively in 52 patients with similar results. KLT generates a synthesis of left ventricular perfusion and kinetics. It facilitates discrimination between normal and pathological acquisitions with high predictive values.     

Facteurs influençant la structure des groupements de macro-invertébrés benthiques et phytophiles dans la zone littorale du Saint-Laurent (Québec)

In the littoral zone of the St-Lawrence River (Quebec, Canada), benthic and phytophilous macroinvertebrates were studied in order to find and to explain relationships between structure of these animal communities and abiotic (substrate, water depth, current velocity) or biotic (marophytes species) factors. Benthos was sampled at 16 sites in spring, when there was no macrophytic vegetation, and in summer. Phytomacrofauna was sampled at 30 sites in summer. The data were analyzed using simple and partial correlations, stepwise regression, reciprocal averaging and canonical correlation analysis.

     

Évolution des peuplements de foraminifères pendant la crise toarcienne à l’exemple des données des monts des Ksour (Atlas saharien occidental,Algérie)

The micropalaeontologic analysis of the Lower Toarcian from the Ksour Mountains (western Saharan Atlas, Algeria) allows us to recognize several assemblages of benthic foraminifera and to obtain information about the deposit environment. These assemblages dominated by Nodosariids are organized in four successive stages of settlement (normal, survival, extinction, and repopulation). This distribution gives new information on the environmental conditions and on their effect on the change in the vertical distribution of benthic foraminifera. The quantitative evolution documents a progressive deepening of the environment that is controlled by local tectonic and sedimentary dynamics. The result is an ecosequence depending both on the general sea-level rise and on a progressive confinement of the bottom water. The normal stage occurred at the beginning of the Polymorphum zone; uncoiled and small sized Nodosariids species indicate the opening of the Atlasic furrow. After, during the middle of this zone, these species were associated with Polymorphinids and Ceratobuliminids, which indicate a deep but isolated and confined environment (survival stage). The ecosequence ended with an episode without foraminifera; it is the extinction stage dated in the Polymorphum and Early Levisoni zones. This stage corresponds to an umbilicus setting. Such palaeophysiographic conditions exaggerated the general coeval hypoxy, responsible of the main Toarcian crisis. Then, from the late Levisoni zone to the end of the Middle Toarcian, the ecosequence evolution is inverted, as a consequence of the filling of the deep parts of the umbilicus, which were less partitioned and more oxygenated (repopulation stage).     

Recherche de cas médicaux multimodaux à l’aide d’arbres de décision

In this article, we present a Case-based Reasoning system for the retrieval of patient files similar to a case placed as query. We focus on patient files made up of several images with contextual information (such as the patient age, sex and medical history). Indeed, medical experts generally need varied sources of information (which might be incomplete) to diagnose a pathology. Consequently, we derive a retrieval framework from decision trees, which are well suited to process heterogeneous and incomplete information. To be integrated in the system, images are indexed by their digital content. The method is evaluated on a classified diabetic retinopathy database. On this database, results are promising: the retrieval sensitivity reaches 79.5% for a window of five cases, which is almost twice as good as the retrieval of single images alone.     

Application de la réaction de Hotchkiss MacManus à la caractérisation semi-quantitative des acides sialiques tissulaires

Résumé Les principaux paramètres conditionnant la spécificité et la sensibilité de la réaction de Hotchkiss MacManus et des hydrolyses chimique et enzymatique de l'acide sialique furent déterminés avec précision, puis la méthode fut appliquée à divers tissus de Rat et de Mouton fixés et inclus, ou fixés brièvement et coupés au cryostat, ou encore simplement coupés au cryostat; la coloration du réactif de Schiff fut mesurée à l'électrophotomètre. Seuls, certains tissus fixés, inclus et traités par la neurammidase donnèrent des résultats satisfaisants. L'hydrolyse enzymatique appliquée aux tissus frais coupés au cryostat provoqua des pertes non sélectives de glycogène hépatique et de glycoprotéines.

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Application of the Hotchkiss MacManus reaction to the semi-quantitative characterisation of tissue sialic acids

Summary A method based on electrophotometric measurement of the contribution of sialic acids to PAS coloration was studied and applied to a number of tissues of the rat and sheep, fixed and embedded. or fixed and sectioned on the cryostat or freshly sectioned on the cryostat; for this, the main factors governing the specificity and sensitivity of the Hotchkiss MacManus reaction and the chemical and enzymatic hydrolysis of sialic acid were accurately determined, then this technique was similarly applied to two types of tissues; the submaxillary gland and the brain, both very rich in sialo-glycoproteins and sialo-lipids, and the liver in which sialic acid is relatively low. This method appeared able to give satisfactory results with certain tissues very rich in sialo-glycoconjugates, provided that the latter have been fixed—sectioned or not on the cryostat—and treated with neuraminidase. Chemical hydrolysis gave in effect conflicting results, and enzymatic hydrolysis applied to the fresh tissue cryostat sections provoked nonspecific losses of hepatic glycogen, glycoproteins and proteins through aqueous degradation in the enzyme solution.

     

Les théories de l’économie animale et l’émergence de la psychiatrie de l’Encyclopédie à l’aliénisme

The author analysesEncyclopédie’s articles devoted to nervous and mental functioning and disorders, showing that a new approach to lunacy as a mental illness, which is defined in some articles as a “general trouble of the animal economy”, progressively emerged. The term,animal economy, unified physical and moral aspects of the study of man. It was elaborated by XVIIIth century physiologists and was widely accepted by French physicians. This idea is based on the vitalistic thought of the Montpellier school, which equated life with sensibility, and on English medical conceptions of a nervous-centred organism. Later on Philippe Pinel’s work displayed the legacy of these conceptions. On one hand, the comprehensive view of physical and moral dimensions in theanimal economy neutralized the question of an organic or psychogenetic origin of madness. This enabled him to consider it as a determinate field of sensibility interactions and as a medical matter, and to legitimize the group of therapeutic practices that he namedtraitement moral. On the other hand, Pinel departed from the classical conception ofanimal economy by developing his concept of aprinciple of mania, which underlies the manifold symptoms and forms of madness, and which are only perceptible to a trained specialist (aliéniste). The historical development analysed in this article show how alienists were enabled to claim both the wholly medical nature of insanity as disease, and their specific competence as apart from the other medical disciplines. To this extent, Esquirol achieved Pinel’s scientific work.     

L’emploi des méthodes de la théorie des ensembles flous à l’étude biométrique de l’espèce Nummulites millecaput dans la partie occidentale de la Téthys

Application of the fuzzy set theory to the biometric evaluation of the species Nummulites millecaput in the western part of the Tethys. The goal of this paper is to demonstrate the ability of the fuzzy-set theory to contribute to the evaluation of paleontological problems. As an example, the species Nummulites millecaput, Boubée has been chosen. One hundred specimens of this species, collected from four localities (Arrimblar, Adelholzen, Dudar, and Mount-Kotuc) have been prepared (equatorial sections) for the biometric measurement of the external and internal characteristics. First a traditional statistical evaluation was performed, followed by the construction of membership functions, the latter ones expressing in the best way the transitions from one locality to the other. The results of this evaluation confirmed that from Aquitaine (France) to Armenia, the same species – Nummulites millecaput – was distributed during the Eocene. To cite this article: G. Bárdossy et al., C. R. Palevol 2 (2003).     

Influence de la congélation sur le taux de fragmentation de l’ADN des spermes normaux à sévèrement altérés

Ejaculated sperm cryopreservation can be proposed in the course of anART procedure, particularly in the case of severe oligozoospermia likely to deteriorate. The aim of this study was to evaluate the influence of the freezing-thawing process on sperm DNA fragmentation (analysed by the TUNEL technique). The first step of this work consisted of adapting the TUNEL technique to perform this analysis on very poor quality sperm. A study was then performed on 72 patients divided into 4 groups according to their spermatic characteristics: group 1 [n=20] (“normal” parameters according to WHO), group 2 [n=24] (normal sperm count associated with asthenospermia and/or teratospermia), group 3 [n=16] (total sperm count between 5 and 20 M) and group 4 [n=12] (total sperm count below 5 M). Spermatic parameters and DNA fragmentation (performed by TUNEL in situ technique, 400 spermatozoa read per slide) were evaluated on raw semen - for all patients -, raw migrated sperm - for patients of group 1 and 2 -, migrated frozen-thawed sperm - for all patients-. A TUNEL technique adapted to oligospermic samples was developed, manipulating spermatozoa directly on the slide rather than in suspension, to limit spermatic sample loss. After the whole migration-freezing-thawing process, the mean DNA fragmentation rate decreased for patients in group 1 (2.9 vs 5.1%, p<0.0001) whereas this rate increased for patients in groups 2 (10.5 vs 6.8%, p<0.0001), 3 (10.7 vs 7.6%, p<0.05) and 4 (15.2 vs 8.7%, p<0.005). DNA fragmentation rates from thawed samples were also correlated with initial spermatic parameters. At the intermediary step, migration decreased DNA fragmentation rate in comparison with raw semen rate in both groups (1.9 vs 4.7% [p<0.05] in group 1; 2.5 vs 5.4% [p<0.05] in group 2). DNA fragmentation rate decreases after migration and then increases after freezing-thawing so that this rate is lower than the raw semen rate for “normal“ sperms and higher than the raw semen rate for altered sperms. Nevertheless, this DNA damage induced by cryopreservation on altered sperms remains moderate. Sperm “resistance” to cryopreservation also appears to depend on spermatic parameters. Cryopreservation may positively select spermatozoa, accelerating elimination of senescent spermatozoa by necrosis, so that early apoptotic spermatozoa from fresh ejaculate are not found in thawed samples. These results, that need to be completed by a study on a larger sample of oligospermic patients, encourage us to continue cryopreserving severely altered sperms.     

Contribution à l'analyse des structures forestières 2. Caractérisation et analyse du toit de la végétation

Data used come from point-height analysis. 100 sample points are arranged in 4 lines of 25, with 24 m between lines and 1 m between points on lines. At each point, vertical lists of species are compiled, by measurement strata. Such strata depth is 10 cm when mean vegetation height in the stand is lower than 4–5 m and 50 cm when heigher. A synthetic vegetation profile is obtained by sum of species presences in each measurement stratum for all 100 observations. When these profiles are bimodal, vegetation can be divided in two at the secondary minimum level: the upper part is the canopy, the lower the understorey. Only the canopy structure is dealt with in this tudy. Several parameters, describing vertical structure of woody vegetation, are defined and measured. They are: (1) maximum height, (2) upper and lower canopy limits, (3) canopy depth and (4) density. Delimitation of canopy is achieved by calculating the hypegeometric probability of realisation groups of vegetation presence, or absence, in the vertical line of sight. The thickness is the difference between the two previous values (2) and (3) and density the number of intercepts between them. Horizontal variations in those structural parameters are revealed by cumulative sum method which demonstrates different types of pattern. Relations between horizontal variations are studied by pairs; actual values compared by linear correlation analysis while concordance between patterns are characterised by the coefficient of simple concordance ofSokal etMitchner and by a binary autocorrelation coefficient.Shannon's formula enables an overall appreciation of canopy homogeneity. an example is applied to some stands ofNothofagus antarctica (Forest) Verst. in Southern Chile and Argentina. The upper canopy limits are the same upper vegetation intercepts so canopies are smooth. High correlation exists between upper and lower limits of the canopies, and low correlation between the latter and thickness and density, so canopies are uniform.     

Influence de la distance à l'océan sur les peuplements ichtyologiques des récifs frangeants de Nouvelle-Calédonie

Coral reef fish are bound to the pelagic environment throughout their larval stage, although they spend most of their adult life on reefs. Thus, the morphology of a lagoon and the location of a reef within the lagoon may influence the nature of its fish assemblage. Because of its asymetrical shape, the SW lagoon of New Caledonia allows us to test such a hypothesis. Several fringing reefs located 4–34 km from the open ocean were compared with one another. No influence of the reef-ocean distance could be found on the global values of diversity, density or biomass. However, presence-absence data of the 343 taxa encountered are related to this distance. Similarly, ecological structures based on diet, size and mobility of fish present strong correlations with reef—ocean distance. Thus, the major effects of an increase in reef—ocean distance concern both taxinomical and ecological structures. Suggested explicative hypotheses are linked to the fish feeding habits closely related to the environment but also to their utilisation of space. Territorial behaviour seems indeed to be important in structuring reef fish assemblage.     

Les inhibiteurs spécifiques de la recapture de la sérotonine dans la dépression de l’enfant et de l’adolescent: revue des controverses récentes

European and US drug regulatory authorities have recently warned against the use of selective serotonin reuptake inhibitors (SSRIs) in childhood and adolescent depression. Through an extensive literature review on the use of SSRIs to treat depression in children and adolescents — including psychiatric clinical trials, pharmacology, and drug safety data — we will: i) describe the main arguments justifying various regulatory decisions; ii) present published data and subsequent meta-analyses; iii) discuss how to integrate the recommendations into daily clinical practice, freeing professionals from a Manichean approach. We reach the limits of evidence-based medicine, which provide the basis of the scientific work of the regulatory authorities.