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Overeem S Kok SW Lammers GJ Vein AA Frölich M Meinders AE Roelfsema F Pijl H 《American journal of physiology. Endocrinology and metabolism》2003,284(3):E641-E647
Narcolepsy is a sleep disorder caused by impaired hypocretin (orexin) neurotransmission. Growth hormone (GH) secretion may be altered in narcolepsy for various reasons. Slow-wave sleep episodes, which are closely associated with GH-secretory events, are more randomly dispersed over 24 h in narcoleptics. Furthermore, hypocretins may inhibit pituitary GH release. We assessed the function of the somatotropic axis in narcolepsy by deconvolving 24-h (10-min sampling interval) plasma GH concentration profiles in seven hypocretin-deficient narcoleptic patients and in seven healthy controls matched for age, sex, and body weight. Both basal and pulsatile GH secretion rate and secretagogue-induced GH release were similar in patients and controls. However, narcoleptics secreted approximately 50% of their total production during the daytime, whereas controls secreted only 25% during the day. Also, the GH output pattern of narcoleptics was significantly less regular. We propose that hypocretin deficiency disrupts the circadian distribution of hypothalamic GH-releasing hormone release in narcoleptic patients to simultaneously cause daytime GH release and promote their propensity to fall asleep during the day. 相似文献
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Macroinvertebrate community loss as a result of headwater stream acidification in the Vosges Mountains (N-E France) 总被引:6,自引:0,他引:6
François Guerold Jean-Pierre Boudot Gilles Jacquemin Denis Vein Denis Merlet James Rouiller 《Biodiversity and Conservation》2000,9(6):767-783
The relationships between water chemistry and aquatic macroinvertebrate communities of 41 headwater streams were studied in the Vosges Mountains (N-E of France) in an attempt to assess the impact of acidification on macroinvertebrate diversity. The taxa richness of macroinvertebrates decreased drastically in headwater streams which were characterized by low pH, low calcium and high aluminum content. All taxonomic groups were affected, but Molluscans, Crustaceans and Ephemeroptera disappeared totally from strongly acidified streams. Simple indices based on taxa richness such as the coefficient of community loss may provide accurate tools to quickly assess the impact of acidification on macroinvertebrate communities. Despite the reduction of atmospheric SO2 emissions, acidification of freshwater in the Vosges Mountains continues to affect streams which were believed in the past to constitute refuge biotopes for numerous species. Consequently, acidification represents a real threat for numerous invertebrates. This study arises the question of the evolution in the future of headwater stream ecosystems. Urgent decisions and interventions are required to preserve non-acidified streams and to restore impacted ecosystems while awaiting spontaneous recovery. 相似文献
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Julie Vein Agnès Leblond Patrick Belli Angeli Kodjo Philippe J. Berny 《European Journal of Wildlife Research》2014,60(1):125-133
Leptospirosis is caused by pathogenic species of the Leptospira genus. Animals can have two roles in the epidemiological cycle: they can be an accidental host and suffer of the disease or a reservoir host which does not express any clinical sign and shed bacteria in their urine. Some of the most known reservoirs for leptospirosis are certain rodent species, but the situation is less clear for aquatic rodents, especially for coypu (Myocastor coypus). It has been shown that this species can have kidney carriage for leptospirosis, but the relationship between carriage and individuals or population health has not been investigated yet. We trapped 133 coypus in two wetlands in the East of France during 3 years. For each animal, a complete necropsy, leptospirosis serology, and a specific real-time quantitative PCR (qPCR) for pathogenic leptospires were performed; in addition, for some animals, a specific kidney culture for leptospires and histology on kidney were performed. In spite of a high seroprevalence (respectively 76 % and 64 %) and of a significant prevalence of kidney carriage in both areas (respectively 12.1 % and 8.0 % of positive qPCR on kidney), the trapped animals seemed in good health, and the population did not seem to be affected by the circulation of the bacteria. These findings are concurring arguments to consider coypu as a real reservoir for leptospirosis. 相似文献
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Adaptation of a real-time PCR method for the detection and quantification of pathogenic leptospires in environmental water 总被引:1,自引:0,他引:1
Vein J Perrin A Berny PJ Benoit E Leblond A Kodjo A 《Canadian journal of microbiology》2012,58(7):828-835
Leptospirosis is a major zoonotic disease that affects humans and animals in all continents, in both rural and urban areas. In Europe, metropolitan France is the most affected country, with about 300 human cases declared per year. In France, although leptospirosis is now mostly considered as a recreational disease related to freshwater areas, isolation of pathogenic leptospires from environmental water samples still remains difficult. It thus seemed important to set up an efficient method to detect and quantify these bacteria in this environment. We determined a DNA extraction method suitable for freshwater samples and adapted a real-time quantitative PCR based on the detection of the LipL32 gene using the SYBR green chemistry. The method developed is specific for pathogenic Leptospira. It permits the detection of all the pathogenic strains tested and none of the saprophytic strains. Quantification is possible between 10 and 10(7) bacteria/mL, and therefore, the method represents a tool that could be integrated into future public health surveillance programs for recreational freshwater areas. 相似文献
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The physico-chemical characteristics and the macroinvertebrate communities of six streams draining a small granitic catchment located in the Vosges mountains (northeastern France) have been studied. Among the streams, five were affected by acidification and characterised by low pH (mean pH: 4.90 to 5.90), low HCO
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concentrations (mean concentration: 0–16 µeq l–1) and elevated aluminium concentrations (mean concentration: 154–278 µg l–1). Only one stream was typical of waters draining granitic bedrock (mean pH: 6.90; mean aluminium concentration: 79 µg 1–1; mean HCO
inf3
sup–
concentration: 152 µeq l–1).The macroinvertebrates communities of the acidified streams were strongly affected compared to the non-acidified one. Richness, abundance and diversity (Shannon index) were significantly lower when acidification occurred. All the major taxonomic groups were affected, but Molluscs and Ephemeroptera were the most acid-sensitive or organisms, whereas Plecoptera and Oligochaetes were dominant. However, recolonization of acidified streams was possible during summer low flow when the global water quality slightly increased.
Résumé Les caractéristiques physico-chimiques et les peuplements de macroinvertébrés benthiques de six ruisseaux drainant un bassin versant granitique du massif vosgien ont été étudiés. Parmi les cours d'eau, cinq sont caractérisés par des faibles valeurs moyennes de pH (4.90 à 5.90), et d'alcalinité (HCO inf3 sup– : 0–16 µeq l–1) et par des concentrations moyennes en aluminium élevées (154–278 µg l–1) Seul un ruisseau apparaît typique du massif (pH: 6.90; aluminium: 79 g l–1 et HCO inf3 sup– : 152 µeq l–1).Les peuplements de macroinvertébrés des ruisseaux acidifiés sont sévèrement affectés. La richesse, l'abondance et la diversité (indice de Shannon) sont alors significativement plus faibles que dans le cours d'eau non acidifié. Tous les groupes faunistiques majeurs sont touchés, mais les Mollusques et les Ephémèroptères sont les organismes les plus sensibles à l'acidification, tandis que les Plécoptères et les Oligochètes sont dominants. Toutefois, il a été mis en évidence une recolonisation possible des rivières acidifiées par certaines espèces, durant la période d'étiage estivale quand la qualité de l'eau s'améliore.相似文献
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