Devant des manifestations hémorragiques chez un enfant, la démarche diagnostique est la même quel que soit son âge. Néanmoins, l'interprétation des résultats doit tenir compte de l'âge puisque les valeurs normales varient de la naissance à la puberté. L'hémostase est un phénomène complexe et dynamique. Les tests dits « de routine » disponibles, comme le temps de céphaline avec activateur (TCA) ou le temps de quick (TQ), explorent des phases spécifiques de la coagulation et des acteurs précis. Il convient de choisir et d'interpréter les examens d'hémostase au regard d'un interrogatoire précis à la recherche de causes acquises ou constitutionnelles. Le bilan d'hémostase est avant tout motivé par une symptomatologie clinique hémorragique (localisation, fréquence) qui orientera elle-même vers le choix des examens à privilégier en première intention. Les pathologies constitutionnelles de l'hémostase sont des anomalies rares de la coagulation. Les formes les plus sévères se manifestent le plus souvent tôt dans l'enfance, alors que les formes mineures sont découvertes de manière fortuite ou se révèlent au cours de challenges hémostatiques (traumatisme, chirurgie, extraction dentaire). Certaines manifestations sont caractéristiques d'anomalie constitutionnelle comme : l'hémorragie du cordon typique des déficits du fibrinogène ou du FXIII, ou l'hémarthrose dans l'hémophilie sévère. Une anomalie de l'hémostase justifiera le recours à un médecin spécialiste pour la caractérisation et la prise en charge.In children with bleeding phenotype, the diagnostic approach is the same regardless of age. Nevertheless, normal values are different at birth than during adulthood, and it is important when interpreting the results to take age into account. Hemostasis is a complex and dynamic process. The routine assays available, APTT (activated partial thromboplastin time) or PT (prothrombin time), explore specific phases with different factors and specific objectives for each. Hemostasis assays should be chosen and interpreted with regard to an accurate examination in search of acquired or constitutional etiology. The assessment of hemostasis is above all based on the hemorrhagic clinical symptomatology (location, frequency), which will itself guide the choice of assay. Bleeding disorders are rare. The most severe forms most often appear in early childhood, while minor forms are discovered incidentally or revealed during hemostatic challenges (trauma, surgery, and dental extraction). Some manifestations are typical of constitutional deficiency, such as umbilical cord hemorrhage and fibrinogen or FXIII deficiency, or hemarthrosis and severe hemophilia. A bleeding disorder or a suspicion of one requires a specialist consultation for characterization and management.

In this paper the performances and the limitations of three multi-elementary analysis techniques are compared applied to a study of air pollution biomonitoring in Morocco. These techniques are: (1) 14 MeV neutron activation analysis (14 MeV-NAA), (2) thermal neutron activation analysis using the k0 quasi-absolute method (k0-NAA) and (3) energy dispersive X-ray fluorescence analysis (ED-XRF). The experimental procedures and the control of the analytical results using certified reference materials are described and discussed. The three methods were confronted for the analysis of lichens, mosses and tree-barks. The complementarity of these methods enabled us to determine 43 elements in different samples. The most suitable method for each element was selected according to the sensitivity and selectivity necessitating the minimum corrections of the matrix effects and/or the interfering reactions.

Iodine-129 is routinely released in the gaseous and liquid low-level radioactive effluents of nuclear spent fuel reprocessing plants. Environmental impact assessment of these discharges are performed based on monitoring samples of different types of natural indicators. Thyroid is considered as a relevant organ to monitor radioactive iodine isotopes. In this study, bovine thyroids were collected in herds located in the Cotentin area under the influence of authorized low level gaseous effluents of the La Hague nuclear fuel-reprocessing plant. For low level 129I/127I ratios, characteristic of environmental samples (10(-12) to 10(-7)), RNAA or SMA that includes important radiochemical preparation steps are used. This paper demonstrates the interest of direct gamma-X spectrometry to measure 129I activities, associated to INAA to measure 127I to attain higher ratios levels (10(-6) to 10(-4)). This study shows the interest of monitoring bovine thyroids considered as sentinel organs to characterize the dispersion in space and time of 129I discharged in low level radioactive gaseous effluents by the La Hague reprocessing plant.

Since 1945, the explosions of nuclear devices in the atmosphere and the increasing effluent discharge from the nuclear spent fuel reprocessing plant contributed to significantly enhance the production of I in the environment [1]. Its activity has increased with time in various components of the atmosphere, hydrosphere and geosphere compartments [2]. While the pre-nuclear I/I ratio is estimated between 10 and 10, nowadays, it reaches levels near 10 in the vicinity of european nuclear fuel reprocessing plants [3, 4]. Thus, the I activity monitoring in the environment of fuel reprocessing plants requires particular radioecological studies to assess the corresponding impact on human population [5].