Le pré-analytique en hémostase

La phase pré-analytique est celle de tous les dangers, en particulier lorsque le biologiste n’a pas la ma?trise du recueil de l’échantillon et de son acheminement au laboratoire. En hémostase thrombose, elle est essentielle. Les paramètres pré-analytiques sont d’importance inégale selon les différents examens et leur retentissement peut varier d’un réactif à l’autre et selon les patients. De fait, il existe un risque de rendre un résultat erroné, même avec une technique irréprochable, ainsi qu’un problème de responsabilité technico-légale. La littérature sur les conditions pré-analytiques est pauvre et de nouvelles études sont nécessaires, même si elles sont difficiles à mener et peuvent para?tre de peu d’intérêt. En réalité, leur utilité est aujourd’hui indéniable, en raison notamment du regroupement des laboratoires.     

L'accessibilité, terme nouveau en Phytogéographie

Accessibility a new term in plant ecology (Summary) For a better understanding of the causal relations between a certain unit of vegetation and its station the proposal is put forward to designate as accessibility factors the totality of conditions prevailing at a certain locality, that may influence the possibility of diaspores to reach that spot and settle there.The accessibility factors must be considered as a separate group of ecological conditions beside and comparable to, but specifically differentiated from the climatical, edaphical and biotical groups of factors.Exactly in the same way as plants become distributed according to their specific faculties to meet the local conditions of climate and soil, they are in a similar way selected on account of the interaction between their migratory faculties and the accessibility factors occurring at a certain locality.The habitat of a certain plant association must therefore be defined on the basis of its climatic, edaphic, biotic and accessibility factors.Objections raised against this proposal may be refuted by compairing the significance of accessibility conditions with the effect exercised by conditions of climate and soil with reference to settling.A mountain range e.g. may influence the accessibility together with the climate of the leeside country by acting as a screen to the winds that bring over rain as well as plant seeds.Accessibility conditions are of great importance with respect to pioneer vegetations on bare soil and in those plant groupings within which phytosociological succession is in rapid progress. However there are many other cases where they surely must be taken into consideration.An illustration of the aforesaid considerations is furnished by vegetations of microscopical algae in small ponds. The astonishing richness in species of one such pond as compaired to some others, may in some cases be explained by exceptionally favorable accessibility, caused for example by the regular visit of migratory water birds.The study of accessibility conditions is quite necessary for the selection and conservation of small nature reserves in highly cultivated regions.

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Reçu par la rédaction le 11.I.1954.     

Illustrations cliniques en pédiatrie

The examples and clinical cases presented in this section are not intended to be considered as absolute models in terms of image quality or device parameter settings. They must initiate an individual analysis according to CT parameters and image quality. Nevertheless, they present practically different CT levels which can be used according to the clinical context and the type of device.     

Illustrations cliniques en ostéo-articulaire

The examples and clinical cases presented in this section are not intended to be considered as absolute models in terms of image quality or device parameter settings. They must initiate an individual analysis according to CT parameters and image quality. Nevertheless, they present practically different CT levels, which can be used according to the clinical context and the type of device.     

Les profils de composition en oligoéléments des pollens,marqueurs potentiels en cladistique végétale

In botany tentative attempts have been made to classify species, based not on the plant as a whole, but on a particular character, for example pollen characteristics. Pollen, which is involved in the transmission of male genetic information during sexual reproduction, is of particular interest in distinguishing plants and their relationships.

These characters, observed in photon- and scanning electron- microscopy are symmetry, form, number and position of germinating areas. Being genetically stable for a given species, they identify a plant.

Recently, a novel character has been added: the concentration of elements in the exine, determined by electron probe micro-X-ray analysis. It is interesting to follow relationship of plant species, based on the mineral composition of their pollen as a whole, taking into account both plastic and oligoelements, obtained via an inductive coupled plasma spectrometer. Samples of pollen from different plant species, at distinct taxonomic levels, were analyzed; the results were submitted to a normalisation procedure and the standard patterns obtained were investigated by means of a number of numerical techniques (clustering and factor analysis). The aim was to establish if elements could be considered as chemical markers in plant cladistics. The mineral composition in a given species appeared quite stable and this furnished a convenient identification-critorion.

This approach further allows a chemo-taxonomy of species, in as much as organization of families, and perhaps orders, would conform to the phylogenetic proximity-criterion. Hence, we found clusters including pollen of Gramineae, Coniferae, Betulaceae…

This methodology, that should be completed and corroborated on a wider range of samples would provide an original responsee to the problems of identification and classification encountered in a pollen bank. It follows that:

Hence, the working hypothesis that the chemical markers and, in particular, oligo-elements, complete pollen typologies based on morphological and structural characters, appears quite reasonable.

In conclusion, this paper brings a complement to the mineral composition of the exine.

En botanique, des tentatives ont été faites pour classer les espèces non plus à partir d'individus pris dans leur intégralité, mais sur la base d'une de leurs particularités, par exemple à partir des caractéristiques offertes par les pollens. Ainsi, le pollen, dont le rôle est de transmettre l'information génétique mâle de la plante au moment de la reproduction sexuée, présente des caractères de premier ordre utilisables pour distinguer les différentes plantes et pour situer leur parenté et leur filiation.

Ces caractères, que l'on observe en microscopies photonique et électronique à balayage sont la symétrie, la forme, le nombre et la position des zones germinatives. Pour une espèce génétiquement stable, ils constituent la carte d'identité de la plante.

Il est intéressant de continuer à explorer la voie de la structuration des espèces végétales basée sur la connaissance chimique du pollen en déterminant sa composition en oligo-éléments par l'utilisation d'un spectromètre à plasma à couplage inductif. Ainsi, des échantillons de pollens appartenant à diverses espèces végétales situées à différents niveaux taxinomiques ont été analysés et les résultats normalisés sous forme de profils standard ont été soumis à différentes techniques d'analyse statistique mathématique (classification automatique et analyse factorielle). Le but de cette approche est d'apprécier l'aptitude des éléments minéraux à être des marqueurs chimiques en cladistique végétale.

Les résultats obtenus ont permis de constater la relative stabilité du profil en composition minérale au sein d'une même espèce végétale, ce qui donne accès à un critère d'identification commode.

Cette approche permet d'autre part une chimiotaxinomie des plantes étudiées.

Cette approche méthodologique semble susceptible d'apporter une réponse originale aux problèmes de conservation. Les pollens conservés doivent avoir la même composition minérale que les pollens frais.

— the pattern of pollen composition of oligo-elements, calcium and magnesium is a marker in plant cladistics. Since a typology depending on proximity is found between plant species, families and orders.

— an unknown pollen sample may be located, tentatively, on the base of a described model of pollen relation (shortest connexion network — Prim algorithm — and pollen of Bactris-oil palm and Phoenix dactylifera).     

Les essais cliniques en médecine nucléaire

The EU clinical trials directive (2001/20/EC) was published on the 4th April 2001 and was transposed into French law in 2004. This new clinical trial regulation has modified considerably the research area including clinical trials conducted with radiopharmaceutical medicinal products. This new regulation aims at ensuring the protection of the health and safety of clinical trial participants, the ethical soundness and the reliability and robustness of data generated in clinical trials. In practice, the sponsor has to submit a clinical trial application to the Afssaps for authorization and to the concerned Ethics Committee for a positive opinion. The content of the clinical trial application regarding the investigational medicinal product is very detailed and a heavy technical dossier could be required in order to justify the quality of the medicinal product used in the clinical trial. Furthermore, pharmacy and radiopharmacy required specific authorizations for preparing these medicinal products. This new regulation could refrain nuclear medicine from conducting clinical trials.     

Blessé médullaire: prise en charge en andrologie

Sexual reactions are under neurological control. Spinal cord trauma alters neurological structure and induces sexual dysfunction. Pharmacological drugs used currently allow erectile function to be recovered in spinal cord-injured men, an essential step towards the resumption of a sex life. Triggering of ejaculation is often difficult. Perineal stimulation techniques, used either in isolation or in association with pharmacological treatment, promote ejaculation and allow sperm collection and freezing. The possibility of achieving ejaculation during sexual intercourse in spinal cord-injured men remains rare and there is as yet no real therapy available. Despite poor semen quality, spinal cord-injured men maintain reproductive possibilities in 40 to 60% of couples. The use of assisted reproductive technologies is often required. Management of sexual dysfunction in spinal cord-injured men must be integrated into a rehabilitation and re-insertion programme.     

Le Jas d’en Biel 2, nouveau site gravettien du piémont est-méditerranéen des Pyrénées

The Corbières massif forms the lowest part of the Eastern Pyrenees, and as such is the easiest natural passage to connect the coastal plains of Languedoc and Roussillon in Southern France with those of Gironès and Barcelona in Northern Spanish Catalonia. This geographical situation confers on each of the sites discovered in this passage a role of milestone that can allow us to apprehend the dynamics of anthropic movements and relationships across these spaces. In 2007, the presence of a first Gravettian site in this Northern Pyrenean foothill was published: Jas d’en Biel 1. This discovery filled an “archaeological void” between the Gravettian sites of Languedoc and those of Spanish Catalonia. The discovery of a new site: Jas d’en Biel 2, 300 m from the first, reinforces the Gravettian presence in this region. The fact that the two sites present similar characteristics in terms of anthropic choices (solar orientation, proximity to a watercourse, lightness of the soil, protection from the wind, etc.) are all parameters that demonstrate the choices made by Gravettian men. The respective compositions of the lithic industries of the series do not show significant differences, allowing us to imagine a certain synchronism between the two sites. Burins are the most numerous tools, but at Jas d’en Biel 2 we find specimens close to the Raysse type that were absent from Jas d’en Biel 1. Jas d’en Biel 2, as well as its neighbor Jas d’en Biel 1, shows similarities with certain sites in Languedoc, such as Bois-des-Brousses, La Treille, La Verrière, the caves of Bize or La Crouzade. These are usually small deposits that belong to terminal moments of the Gravettian period. All these parameters point to similarities between the Languedoc sites and Jas d’en Biel 1 and 2. The geographical position of the Corbières massif allows us to consider the Jas d’en Biel sites as the last milestones of the Gravettian period upstream from the crossing of the Pyrenean passes, before the sites of the Serinyà region, such as l’Arbreda. Recent surveys carried out in the same valley of the Ravin d’en Saman have made it possible to locate and identify several other open-air settlements related to the Gravettian lato sensu. An analysis of intra- and extra-site characteristics will aim to understand the parameters that led men to settle in this micro-zone, as well as the reasons for this “concentration”.     

Familles moléculaires et réactions croisées en allergie

Le risque pour une personne de développer des manifestations allergiques est plus grand si elle a des antécédents familiaux d’allergie: on parle de terrain atopique.     

Préparations magistrales en radiopharmacie : contraintes liées à la mise en place

Use of radiopharmaceuticals in French nuclear medicine departments depends on marketing authorization and their development may be compromised by a limited return on investment. As an alternative, radiopharmaceuticals may also be prepared in the form of a magistral preparation, like in some European countries. In this case, these preparations are subjected to restrictions and requirements for radiopharmacies relating to quality assurance, facilities and equipment, quality of starting materials and final radiopharmaceutical products defined in French good preparation practice. Labelled tracers used as magistral preparations have to be prepared under the full responsibility of a radiopharmacist and used under the responsibility of the prescribing physician. Conditions of sufficient guarantees for the safety of the patient and adherence to pharmaceutical rules must be evaluated individually. However, this form of preparation intends to supply specific medical needs for an individual patient and is not an answer in the framework of development of radiopharmaceuticals.     

La simulation Monte Carlo en médecine nucléaire

The Monte Carlo method allows for simulating random processes by using series of pseudo-random numbers. It became an important tool in nuclear medicine to assist in the design of new medical imaging devices, optimise their use and analyse their data. Presently, the sophistication of the simulation tools allows the introduction of Monte Carlo predictions in data correction and image reconstruction processes. The availability to simulate time dependent processes opens up new horizons for Monte Carlo simulation in nuclear medicine. In a near future, these developments will allow to tackle simultaneously imaging and dosimetry issues and soon, case system Monte Carlo simulations may become part of the nuclear medicine diagnostic process. This paper describes some Monte Carlo method basics and the sampling methods that were developed for it. It gives a referenced list of different simulation software used in nuclear medicine and enumerates some of their present and prospective applications.     

Réflexions sur la place des médecins spécialistes en médecine nucléaire dans le dispositif d’annonce en cancérologie

Nuclear medicine physicians are very involved in French's oncology announcement procedure. However, their role needs to be analysed and evaluated. Before diagnosis’ announcement, information provided by nuclear medicine physicians are never neutral for patients. Information must not increase patient's anxiety or false patient's sense of reassurance. In this context, it seems necessary to engage in ethical reflexions about nuclear medicine physicians communication challenges.