Effets des perturbateurs endocriniens au cours du développement : interactions précoces et délais variables de manifestation

peer reviewe

Early homeostatic disturbances of human growth and maturation by endocrine disrupters

peer reviewedWe attempt to delineate and integrate aspects of growth and development that could be affected by endocrine disrupters [endocrine-disrupting compounds (EDC)], an increasing public health concern. RECENT FINDINGS: Epidemiological and experimental data substantiate that fetal and early postnatal life are critical periods of exposure to endocrine disrupters, with possible transgenerational effects. The EDC effects include several disorders of the reproductive system throughout life (abnormalities of sexual differentiation, infertility or subfertility and some neoplasia) and disorders of energy balance (obesity and metabolic syndrome). The mechanisms are consistent with the concept of 'developmental origin of adult disease'. They could involve cross-talk between the factors controlling reproduction and those controlling energy balance, both in the hypothalamus and peripherally. SUMMARY: Due to ubiquity of endocrine disrupters and lifelong stakes of early exposure, individual families should be provided by pediatricians with recommendations following the precautionary principle, that is prevention or attenuation of conditions possibly detrimental to health before the evidence of such adverse effects is complete and undisputable

Endocrine-disrupting chemicals and human growth and maturation: a focus on early critical windows of exposure.

Endocrine-disrupting chemicals (EDCs) are exogenous substances that interfere with hormone synthesis, metabolism, or action. In addition, some of them could cause epigenetic alterations of DNA that can be transmitted to the following generations. Because the developing organism is highly dependent on sex steroids and thyroid hormones for its maturation, the fetus and the child are very sensitive to any alteration of their hormonal environment. An additional concern about that early period of life comes from the shaping of the homeostatic mechanisms that takes place also at that time with involvement of epigenetic mechanisms along with the concept of fetal origin of health and disease. In this chapter, we will review the studies reporting effects of EDCs on human development. Using a translational approach, we will review animal studies that can shed light on some mechanisms of action of EDCs on the developing organism. We will focus on the major hormone-dependent stages of development: fetal growth, sexual differentiation, puberty, brain development, and energy balance. We will also discuss the possible epigenetic effects of EDCs on human development

Les images satellitaires Radar. Utilisation en cartographie géologique et exploration minière (Guyane, Côte-d'Ivoire).

International audienceThe aim of the AURROS project conslsted in demonstrating the use of satellite radar data on sites representative of the problems encountered in geological and mineral exploralion. The objective is to improve characterisation methods for target zones, parlicularly in the early stages of the process leading to mining permit application. The dalabase integrales ERS (l and 2) data, RADARSAT (broad-swath Seansar mode and fine bi-angular viewing made) data, DEMs acquired by various means, and geophysical dala (airborne magnelics, spectral radiomelry). Various me/hods (fil/ering, geocoding and stereoscopy) have heen integrated or developed by BRGM to create differenl map types. These dala are analysed at various scales and validated using hvo approaches, namely checking in Ihe field and fusion wilh airhome geophysical data (spectral radiometry and aeromagnetics). The first results showed the radar to be a powerful mapping and deposit-prediction tool, and notably revealed that 1) the raw data con be used directly by geologists either for standard geological studies or as an exploration aid, and 2) fusion with geophysical data enables the identification of deformation structures where geophysics alone only reveals large masses, and rapidly and efficiently increases the possibilities of lithological discrimination. Correct use of the data nevertheless involves taking into consideration the scales used and currenl restrictions concerning the most suitable study environments. The development possibilities associated with radar stereoscopy constitute a major progress factor for the near future

Female sexual maturation and reproduction after prepubertal exposure to estrogens and endocrine disrupting chemicals: A review of rodent and human data

Natural hormones and some synthetic chemicals spread into our surrounding environment share the capacity to interact with hormone action and metabolism. Exposure to such compounds can cause a variety of developmental and reproductive detrimental abnormalities in wildlife species and, potentially, in human. Many experimental and epidemiological data have reported that exposure of the developing fetus or neonate to environmentally relevant concentrations of some among these endocrine disrupters induces morphological, biochemical and/or physiological disorders in brain and reproductive organs, by interfering with the hormone actions. The impact of such exposures on the hypothalamic-pituitary-gonadal axis and subsequent sexual maturation is the subject of the present review. We will highlight epidemiological human studies and the effects of early exposure during gestational, perinatal or postnatal life in female rodents. (c) 2006 Elsevier Ireland Ltd. All rights reserved

Clay Minerals Mapping from Imaging Spectroscopy

Mapping subsurface clay minerals is an important issue because they have particular behaviors in terms of mechanics and hydrology that directly affects assets laid at the surface such as buildings, houses, etc. They have a direct impact in ground stability due to their swelling capacities, constraining infiltration processes during flooding, especially when moisture is important. So detecting and characterizing clay mineral in soils serve urban planning issues and improve the risk reduction by predicting impacts of subsidence on houses and infrastructures. High-resolution clay maps are thus needed with accurate indications on mineral species and abundances. Clay minerals, known as phyllosilicates, are divided in three main species: smectite, illite, and kaolinite. The smectite group highly contributes to the swelling behavior of soils, and because geotechnical soil analyses are expensive and time-consuming, it is urgent to develop new approaches for mapping clays’ spatial distribution by using new technologies, e.g., ground spectrometer or remote hyperspectral cameras [0.4–2.5 μm]. These technics constitute efficient alternatives to conventional methods. We present in this chapter some recent results we got for characterizing clay species and their abundances from spectrometry, used either from a ground spectrometer or from hyperspectral cameras

Early developmental actions of endocrine disruptors on the hypothalamus, hippocampus, and cerebral cortex.

peer reviewedSex steroids and thyroid hormones play a key role in the development of the central nervous system. The critical role of these hormonal systems may explain the sensitivity of the hypothalamus, the cerebral cortex, and the hippocampus to endocrine-disrupting chemicals (EDC). This review examines the evidence for endocrine disruption of glial-neuronal functions in the hypothalamus, hippocampus, and cerebral cortex. Focus was placed on two well-studied EDC, the insecticide dichlorodiphenyltrichloroethane (DDT) and polychlorinated biphenyls (PCB). DDT is involved in neuroendocrine disruption of the reproductive axis, whereas polychlorinated biphenyls (PCB) interact with both the thyroid hormone- and sex steroid-dependent systems and disturb the neuroendocrine control of reproduction and development of hippocampus and cortex. These results highlight the impact of EDC on the developing nervous system and the need for more research in this area

Paramétrisation du potentiel de ruissellement des bassins versants au moyen de la Télédétection et des systèmes d'Informations Géographiques. Application à des bassins versants du Pays de Caux

International audienceThe increasing number of run-off damages occurring in Pays de Caux is a serious concern for regional authorities. The suggested method aims the assessmenl of run-off parameters using Remote Sensing and GIS. This method allows an objective comparison of the intrinsic and anthropic pressures of cultivated catchment from 1000 to 5000 ha. The potenliaI ron-off characteristics are analysed using land use components increasing or limiting run-off. and their spoliaI distrihulion on three different functional units. The selected parameters are the grassland proportion and compacity around concentrated surficial water channels (80 m wide), the proportion and compacity of the soil surfaces contributive to run-off on the top of catchments and, finally, the simple proportion of grassland and forest upon high sloped areas. The temporal evolution of these indices and the comparison between calchments show the signiflcant recorded changes whÎch favour the increase of surfaces contributing la mn-off between 1990 and /997. The interest of Ihese indices is to identify areas sensitive to run-off and to act as a decision supporl tool for a lerritorial management policy aimed al run-off reduclion on catchments. The outlook of this study is to generalize these parameters for regional applications

CHA2DS2-VASc Score for Predicting Stroke and Thromboembolism in Patients With AF and Biological Valve Prosthesis

International audienc