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haplotype HLA et narcolepsie / SAS et syndrome métabolique / orexine et régulation veille-sommeil / trouble bipolaire et rythmes circadiens

Troubles respiratoires
Une étude parue dans la revue Metabolic Syndrom Related Disorders (17 août 2010)met en évidence une association indépendante entre syndrome d’apnées du sommeil et syndrome métabolique établie à partir d’examens polysomnographiques,  tests glycémiques et lipidiques et examen de la pression artérielle effectués sur des indiens d’Asie atteints d’obésité et de ronflements.
Chronobiologie
La revue Bipolar Disorders (12 août 2010 (5):459-72) propose un examen critique des études réalisées autour de la corrélation hypothétique  entre rythme circadien, sommeil et régulation des émotions en contexte pathologique de trouble bipolaire.
Psychiatrie
Une étude parue dans Autism Research (17 août 2010) vient calculer la cohérence électroencéphalographique enregistrée chez des patients atteints d’autisme vs population contrôle en sommeil paradoxal, phase de sommeil caractérisée par activation corticale endogène. Les données recueillies  viennent conforter l’hypothèse d’une connectivité accrue entre le cortex visuel et les autres régions du cerveau, connectivité qui serait propre à l’autisme.
Médecine du travail
La revue BMC Health Service Research (Août 2010 15;10(1):239) envisage les effets du travail de nuit d’un échantillon de praticiens anesthésistes et pédiatres soumis notamment dans le cadre de leur activité à 16 heures de veille continue, afin d’impulser des aménagements de temps de travail susceptibles de respecter les besoins de recouvrance spécifiques de cette population. Dans le cadre de cette étude, ces besoins apparaissent manifestement relativement aisés à satisfaire bien que tout travail de nuit requiert une approche plus globale, sur le long terme, des effets observés sur la santé des individus.
Neurosciences
Une étude parue dan le Journal of Molecular Neurosciences (14 août 2010) attire l’attention sur l’incidence physiologique de l’augmentation du mode de transmission orexinergique observée sur des modèles animaux dans la perspective d’une mise à l’épreuve des effets des agonistes de l’orexine comme agents thérapeutiques probants dans le traitement de la narcolepsie.
Génétique
Une étude intitulée « Genome-wide association study identifies new HLA class II haplotypes strongly protective against narcolepsy »  et parue dans la revue Nature Genetics(15 août 2010) prétend porter plus loin l’appréhension et la compréhension des fondements génétiques du risque de narcolepsie. Elle en parvient à  identifier une fonction « immunisante » (protective) inattendue de l’haplotype HLA (antigènes des leucocytes humains) et suggère ainsi une implication éventuelle de type causale de la région HLA dans la susceptibilité à la narcolepsie.


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Metabolic Syndrom Related Disorders. 2010 Aug 17. [Epub ahead of print]
Obstructive Sleep Apnea is Independently Associated with the Metabolic Syndrome in Obese Asian Indians in Northern India.
Bhushan B, Misra A, Guleria R.
1 Department of Surgery and Otolaryngology, Children's Memorial Hospital, Northwestern University , Chicago, Illinois.
Abstract
Abstract Introduction: Obesity and the metabolic syndrome are rapidly increasing in developing countries. Whether the metabolic syndrome is independently associated with obstructive sleep apnea (OSA) is not clear. Objective: This study investigated the association between OSA and the metabolic syndrome in obese Asian Indians. Methods: We studied 240 obese subjects [body mass index (BMI) >25 kg/m(2)], 121 with OSA and 119 without OSA, matched for age, BMI, and percentage body fat (%BF). Full-montage digital polysomnography, fasting blood glucose (FBG), lipid levels, and blood pressure (BP) were done in all subjects. Results: Subjects with OSA showed higher prevalence of the metabolic syndrome as compared to subjects without OSA [67.8% vs. 42.02%; chi(2) = 16.08, P < 0.0001, odds ratio (OR) = 2.90, 95% confidence interval (CI)]. Prevalence of the metabolic syndrome was significantly higher in the severe OSA group as compared to the moderate OSA group (78.7% vs. 40.9%; chi(2) = 11.57; P < 0.001; OR = 0.19, 95% CI). Fasting insulin levels were significantly higher in subjects with OSA as compared to subjects without OSA [median (range); 84.03(12.5-541.7) pmol/L vs. 64.4(10.4-520.8) pmol/L; P = 0.002)]. Regression analysis suggested that OSA was independently and positively associated with the metabolic syndrome, male gender, and fasting insulin levels. Conclusion: OSA is independently associated with the metabolic syndrome in Asian Indians in northern India.
PMID: 20715932 [PubMed - as supplied by publisher]
Une étude parue dans la revue Metabolic Syndrom Related Disorders (17 août 2010)met en évidence une association entre le syndrome d’apnées du sommeil et le syndrome métabolique à partir d’ examens polysomnographiques,  testes glycémiques et  lipidiques et examen de la pression artérielle effectués sur des indiens d’Asie atteints d’obésité.
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BMC Health Service Research. 2010 Aug 15;10(1):239. [Epub ahead of print]
Sleep and recovery in physicians on night call: a longitudinal field study.
Malmberg B, Kecklund G, Karlson B, Persson R, Flisberg P, Orbaek P.
ABSTRACT:
BACKGROUND: It is well known that physicians' night-call duty may cause impaired performance and adverse effects on subjective health, but there is limited knowledge about effects on sleep duration and recovery time. In recent years occupational stress and impaired well-being among anaesthesiologists have been frequently reported for in the scientific literature. Given their main focus on handling patients with life-threatening conditions, when on call, one might expect sleep and recovery to be negatively affected by work, especially in this specialist group. The aim of the present study was to examine whether a 16-hour night-call schedule allowed for sufficient recovery in anaesthesiologists compared with other physician specialists handling less life-threatening conditions, when on call.
METHODS: Sleep, monitored by actigraphy and Karolinska Sleep Diary/Sleepiness Scale on one night after daytime work, one night call, the following first and second nights post-call, and a Saturday night, was compared between 15 anaesthesiologists and 17 paediatricians and ear, nose, and throat surgeons.
RESULTS: Recovery patterns over the days after night call did not differ between groups, but between days. Mean night sleep for all physicians was 3 hours when on call, 7 h both nights post-call and Saturday, and 6 h after daytime work (p<0.001). Scores for mental fatigue and feeling well rested were poorer post-call, but returned to Sunday morning levels after two nights' sleep.
CONCLUSIONS: Despite considerable sleep loss during work on night call, and unexpectedly short sleep after ordinary day work, the physicians' self-reports indicate full recovery after two nights' sleep. We conclude that these 16-hour night duties were compatible with a short-term recovery in both physician groups, but the limited sleep duration in general still implies a long-term health concern. These results may contribute to the establishment of safe working hours for night-call duty in physicians and other health-care workers.
PMID: 20712854 [PubMed - as supplied by publisher]
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Autism Research. 2010 Aug 17. [Epub ahead of print]
Enhanced connectivity between visual cortex and other regions of the brain in autism: a REM sleep EEG coherence study.
Léveillé C, Barbeau EB, Bolduc C, Limoges E, Berthiaume C, Chevrier E, Mottron L, Godbout R.
Sleep Laboratory & Clinic, Hôpital Rivière-des-Prairies, Montréal, Québec, Canada.
Abstract
Functional interregional neural coupling was measured as EEG coherence during REM sleep, a state of endogenous cortical activation, in 9 adult autistic individuals (21.1+/-4.0 years) and 13 typically developed controls (21.5+/-4.3 years) monitored for two consecutive nights in a sleep laboratory. Spectral analysis was performed on 60 s of artefact-free EEG samples distributed equally throughout the first four REM sleep periods of the second night. EEG coherence was calculated for six frequency bands (delta, theta, alpha, sigma, beta, and total spectrum) using a 22-electrode montage. The magnitude of coherence function was computed for intra- and interhemispheric pairs of recording sites. Results were compared by Multivariate Analysis of Variance (MANOVA). Each time the autistic group showed a greater EEG coherence than the controls; it involved intrahemispheric communication among the left visual cortex (O1) and other regions either close to or distant from the occipital cortex. In contrast, lower coherence values involved frontal electrodes in the right hemisphere. No significant differences between groups were found for interhemispheric EEG coherence. These results show that the analysis of EEG coherence during REM sleep can disclose patterns of cortical connectivity that can be reduced or increased in adults with autism compared to typically developed individuals, depending of the cortical areas studied. Superior coherence involving visual perceptual areas in autism is consistent with an enhanced role of perception in autistic brain organization.
PMID: 20717953 [PubMed - as supplied by publisher]
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Bipolar Disorders. 2010 Aug;12(5):459-72.
Circadian rhythms and sleep in bipolar disorder.
Murray G, Harvey A.
Faculty of Life and Social Sciences, Swinburne University of Technology, Hawthorn, Victoria, Australia.
Abstract
Murray G, Harvey A. Circadian rhythms and sleep in bipolar disorder. Bipolar Disord 2010: 12: 459-472. (c) 2010 The Authors. Journal compilation (c) 2010 John Wiley & Sons A/S.
Objective: Biological rhythm pathways are highlighted in a number of etiological models of bipolar disorder, and the management of circadian instability appears in consensus treatment guidelines. There are, however, significant conceptual and empirical limitations on our understanding of a hypothesised link between circadian, sleep, and emotion regulation processes in bipolar disorder. The aim of this article is to articulate the limits of scientific knowledge in relation to this hypothesis. Methods: A critical evaluation of various literatures was undertaken. The basic science of circadian and sleep processes, their involvement in normal emotion regulation, and the types of evidence suggesting circadian/sleep involvement in bipolar disorder are reviewed. Results: Multiple lines of evidence suggest that circadian and sleep-wake processes are causally involved in bipolar disorder. These processes demonstrably interact with other neurobiological pathways known to be important in bipolar disorder, but are unique in that they are open to behavioural manipulation. Conclusion: Further research into biological rhythm pathways to bipolar disorder is warranted. Person-environment feedback loops are fundamental to circadian adaptation, and models of circadian pathogenesis (and treatment) should recognize this complexity.
PMID: 20712747 [PubMed - in process]
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Journal of Molecular Neurosciences. 2010 Aug 14. [Epub ahead of print]
Ectopic Overexpression of Orexin Alters Sleep/Wakefulness States and Muscle Tone Regulation during REM Sleep in Mice.
Willie JT, Takahira H, Shibahara M, Hara J, Nomiyama M, Yanagisawa M, Sakurai T.
Howard Hughes Medical Institute and Department of Molecular Genetics, University of Texas Southwestern Medical Center at Dallas, Dallas, TX, 75390-9050, USA.
Abstract
Orexins (also called hypocretins), which are neuropeptides exclusively expressed by a population of neurons specifically localized in the lateral hypothalamic area, are critically implicated in the regulation of sleep/wake states. Orexin deficiency results in narcoleptic phenotype in rodents, dogs, and humans, suggesting that orexins are important for maintaining consolidated wakefulness states. However, the physiological effect of constitutive increased orexinergic transmission tone, which might be important for understanding the effects of orexin agonists that are promising candidates for therapeutic agents of narcolepsy, has not been fully characterized. We report here the sleep/wakefulness abnormalities in transgenic mice that exhibit widespread overexpression of a rat prepro-orexin transgene driven by a beta-actin/cytomegalovirus hybrid promoter (CAG/orexin transgenic mice). CAG/orexin mice exhibit sleep abnormalities with fragmentation of non-rapid eye movement (REM) sleep episode and a reduction in REM sleep. Non-REM sleep was frequently disturbed by short episodes of wakefulness. EEG/EMG studies also reveal incomplete REM sleep atonia with abnormal myoclonic activity during this sleep stage. These results suggest that endogenous orexinergic activity should be appropriately regulated for normal maintenance of sleep states. Orexinergic transmission should be activated during wakefulness, while it should be inactivated or decreased during sleep state to maintain appropriate vigilance states.
PMID: 20711757 [PubMed - as supplied by publisher]
Nat Genet. 2010 Aug 15. [Epub ahead of print]
Genome-wide association study identifies new HLA class II haplotypes strongly protective against narcolepsy.
Hor H, Kutalik Z, Dauvilliers Y, Valsesia A, Lammers GJ, Donjacour CE, Iranzo A, Santamaria J, Peraita Adrados R, Vicario JL, Overeem S, Arnulf I, Theodorou I, Jennum P, Knudsen S, Bassetti C, Mathis J, Lecendreux M, Mayer G, Geisler P, Benetó A, Petit B, Pfister C, Bürki JV, Didelot G, Billiard M, Ercilla G, Verduijn W, Claas FH, Vollenwider P, Waeber G, Waterworth DM, Mooser V, Heinzer R, Beckmann JS, Bergmann S, Tafti M.
[1] Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland. [2] Institut National de la Santé et de la Recherche Médicale U888, Montpellier, France. [3] These authors contributed equally to this work.
Abstract
Narcolepsy is a rare sleep disorder with the strongest human leukocyte antigen (HLA) association ever reported. Since the associated HLA-DRB1*1501-DQB1*0602 haplotype is common in the general population (15-25%), it has been suggested that it is almost necessary but not sufficient for developing narcolepsy. To further define the genetic basis of narcolepsy risk, we performed a genome-wide association study (GWAS) in 562 European individuals with narcolepsy (cases) and 702 ethnically matched controls, with independent replication in 370 cases and 495 controls, all heterozygous for DRB1*1501-DQB1*0602. We found association with a protective variant near HLA-DQA2 (rs2858884; P < 3 x 10(-8)). Further analysis revealed that rs2858884 is strongly linked to DRB1*03-DQB1*02 (P < 4 x 10(-43)) and DRB1*1301-DQB1*0603 (P < 3 x 10(-7)). Cases almost never carried a trans DRB1*1301-DQB1*0603 haplotype (odds ratio = 0.02; P < 6 x 10(-14)). This unexpected protective HLA haplotype suggests a virtually causal involvement of the HLA region in narcolepsy susceptibility.
PMID: 20711174 [PubMed - as supplied by publisher]

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Groupe Santé Sommeil

Le groupe médical Santé Sommeil a pour vocation de diagnostiquer et traiter les troubles du sommeil et de la veille chez l’adulte et l’enfant.