82 results on '"Marie Dumont"'
Search Results
2. Gene copy-number changes and chromosomal instability induced by aneuploidy confer resistance to chemotherapy
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Sara Martin, René Wardenaar, Marica Rosaria Ippolito, Daniele Fachinetti, Valentino Martis, Floris Foijer, Uri Ben-David, Stefano Santaguida, Andréa E. Tijhuis, Christy Hong, Diana C.J. Spierings, Marie Dumont, Johanna Zerbib, Stem Cell Aging Leukemia and Lymphoma (SALL), Damage and Repair in Cancer Development and Cancer Treatment (DARE), and Restoring Organ Function by Means of Regenerative Medicine (REGENERATE)
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Genome instability ,Aneuploidy ,Biology ,PACLITAXEL ,Gene dosage ,General Biochemistry, Genetics and Molecular Biology ,Chromosome instability ,medicine ,Copy-number variation ,Molecular Biology ,Gene ,SPINDLE CHECKPOINT ,DRUG-RESISTANCE ,TOPOISOMERASE-I INHIBITORS ,PROLIFERATION ,Cancer ,Chromosome ,Cell Biology ,medicine.disease ,FRAMEWORK ,PROTEOME ,DISCOVERY ,CELLS ,Cancer research ,MIS-SEGREGATION ,Developmental Biology - Abstract
Mitotic errors lead to aneuploidy, a condition of karyotype imbalance, frequently found in cancer cells. Alterations in chromosome copy number induce a wide variety of cellular stresses, including genome instability. Here, we show that cancer cells might exploit aneuploidy-induced genome instability and the resulting gene copy-number changes to survive under conditions of selective pressure, such as chemotherapy. Resistance to chemotherapeutic drugs was dictated by the acquisition of recurrent karyotypes, indicating that gene dosage might play a role in driving chemoresistance. Thus, our study establishes a causal link between aneuploidy-driven changes in gene copy number and chemoresistance and might explain why some chemotherapies fail to succeed.
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- 2021
3. Impact of early low-calorie low-protein versus standard-calorie standard-protein feeding on outcomes of ventilated adults with shock: design and conduct of a randomised, controlled, multicentre, open-label, parallel-group trial (NUTRIREA-3)
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Christophe Leroy, Agathe Delbove, Guillaume Thiery, Gaëtan Plantefève, Patrice Tirot, Louis Chauvelot, Didier Thevenin, Julien Maizel, Vincent Das, Michael Darmon, Nathalie Thieulot-Rolin, Laurent Guérin, Philippe Letocart, Delphine Chatellier, Francis Schneider, Jérôme Devaquet, Fabien Lambiotte, Jean-Baptiste Lascarrou, Olivier Gontier, Walter Picard, Samir Jaber, Gaël Piton, Isabelle Vinatier, Bruno Giraudeau, Christophe Cracco, Amélie Le Gouge, Jean Pierre Quenot, Nicolas Terzi, Jack Richecoeur, Jean Philippe Rigaud, Sebastian Voicu, Yannick Hourmant, Laurent Brisard, Mai Anh Nay, Jean Reignier, François Tinturier, Djillali Annane, Louis Marie Dumont, Nicolae Vlad Botoc, Thierry Vanderlinden, Florian Reizine, Benjamin Madeux, Pierre Asfar, Samuel Groyer, Fabienne Tamion, Jean Paul Mira, Bertrand Souweine, Saad Nseir, Jean-François Timsit, Bertrand Guidet, Julio Badie, Johanna Oziel, Olivier Martinet, Anne Renault, Frédéric Martino, Christophe Vinsonneau, Diane Maugars, Nadia Aissaoui-Balanant, Michel Sirodot, Laurent Argaud, Hoang Nam Bui, Matthieu Debarre, Alain Combes, Emmanuelle Mercier, Daniel da Silva, Physiologie & médecine expérimentale du Cœur et des Muscles [U 1046] (PhyMedExp), Institut National de la Santé et de la Recherche Médicale (INSERM)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Centre Hospitalier Régional Universitaire [Montpellier] (CHRU Montpellier), and Université de Montpellier (UM)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)
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Adult ,medicine.medical_specialty ,Calorie ,Low protein ,Critical Illness ,medicine.medical_treatment ,[SDV]Life Sciences [q-bio] ,030204 cardiovascular system & hematology ,law.invention ,03 medical and health sciences ,0302 clinical medicine ,Informed consent ,law ,Internal medicine ,Diet, Protein-Restricted ,Humans ,Medicine ,030212 general & internal medicine ,adult intensive & critical care ,nutrition & dietetics ,2. Zero hunger ,Mechanical ventilation ,clinical trials ,Protein feeding ,SARS-CoV-2 ,business.industry ,Intensive Care ,COVID-19 ,General Medicine ,Respiration, Artificial ,Intensive care unit ,3. Good health ,Clinical trial ,Shock (circulatory) ,medicine.symptom ,business - Abstract
IntroductionInternational guidelines include early nutritional support (≤48 hour after admission), 20–25 kcal/kg/day, and 1.2–2 g/kg/day protein at the acute phase of critical illness. Recent data challenge the appropriateness of providing standard amounts of calories and protein during acute critical illness. Restricting calorie and protein intakes seemed beneficial, suggesting a role for metabolic pathways such as autophagy, a potential key mechanism in safeguarding cellular integrity, notably in the muscle, during critical illness. However, the optimal calorie and protein supply at the acute phase of severe critical illness remains unknown. NUTRIREA-3 will be the first trial to compare standard calorie and protein feeding complying with guidelines to low-calorie low-protein feeding. We hypothesised that nutritional support with calorie and protein restriction during acute critical illness decreased day 90 mortality and/or dependency on intensive care unit (ICU) management in mechanically ventilated patients receiving vasoactive amine therapy for shock, compared with standard calorie and protein targets.Methods and analysisNUTRIREA-3 is a randomised, controlled, multicentre, open-label trial comparing two parallel groups of patients receiving invasive mechanical ventilation and vasoactive amine therapy for shock and given early nutritional support according to one of two strategies: early calorie-protein restriction (6 kcal/kg/day-0.2–0.4 g/kg/day) or standard calorie-protein targets (25 kcal/kg/day, 1.0–1.3 g/kg/day) at the acute phase defined as the first 7 days in the ICU. We will include 3044 patients in 61 French ICUs. Two primary end-points will be evaluated: day 90 mortality and time to ICU discharge readiness. The trial will be considered positive if significant between-group differences are found for one or both alternative primary endpoints. Secondary outcomes include hospital-acquired infections and nutritional, clinical and functional outcomes.Ethics and disseminationThe NUTRIREA-3 study has been approved by the appropriate ethics committee. Patients are included after informed consent. Results will be submitted for publication in peer-reviewed journals.Trial registration numberNCT03573739.
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- 2021
4. Towards a better understanding of increased sleep duration in the chronic phase of moderate to severe traumatic brain injury: an actigraphy study
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Jean Paquet, Julie Carrier, Nadia Gosselin, Catherine Duclos, Hélène Blais, Marie Dumont, Héjar El-Khatib, Erlan Sanchez, Caroline Arbour, and Université de Montréal. Faculté des arts et des sciences. Département de psychologie
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Adult ,Male ,Sleep Wake Disorders ,Moderate to severe ,medicine.medical_specialty ,Sleepiness ,Traumatic brain injury ,Polysomnography ,Medication ,Severity of Illness Index ,Bedtime ,Young Adult ,03 medical and health sciences ,0302 clinical medicine ,Surveys and Questionnaires ,Mood ,Brain Injuries, Traumatic ,Humans ,Medicine ,Fatigue ,business.industry ,Actigraphy ,General Medicine ,Sleep quality ,medicine.disease ,Sleep in non-human animals ,nervous system diseases ,3. Good health ,Cross-Sectional Studies ,nervous system ,030228 respiratory system ,Duration (music) ,Case-Control Studies ,Physical therapy ,Female ,Sleep diary ,Sleep ,business ,030217 neurology & neurosurgery - Abstract
Introduction Most adults with moderate to severe traumatic brain injury (TBI) report persistent sleep-wake disturbances. Whether these complaints are either associated with abnormal sleep-wake patterns or can be explained by TBI-related characteristics is unclear. The present study aimed at characterising the subjective and objective sleep-wake patterns in TBI adults by taking into consideration the influence of TBI severity, common comorbidities and psychoactive medication. Methods Overall, 34 adults with moderate-severe TBI (one to four years post-injury) were compared to 34 controls. Sleepiness, fatigue, sleep quality, mood, and pain were assessed with questionnaires. A seven day sleep diary and actigraphy was used to document sleep and wake patterns. Results Compared to controls, TBI participants reported more sleepiness and fatigue, as well as poorer sleep quality. On actigraphy, they had earlier bedtime and longer time spent in bed, but equivalent sleep efficiency during the nighttime episode compared to controls. TBI participants also took more naps and accumulated more time asleep over the 24 h period than controls. These group differences were accentuated when only TBI adults using psychoactive medication were included. More comorbidities, more severe injuries and longer hospital stay were positively correlated with fatigue, sleepiness and sleep duration. Conclusions Our results showed that despite complaints regarding sleep and diurnal functioning, TBI survivors have very marginal changes in their objective sleep-wake schedules. Prolonged time spent in bed may reflect an attempt to increase their sleep duration in response to fatigue and sleepiness. TBI adults who use psychoactive medication are those with more evident changes in their sleep-wake schedules.
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- 2019
5. Extracorporeal membrane oxygenation network organisation and clinical outcomes during the COVID-19 pandemic in Greater Paris, France: a multicentre cohort study
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Guillaume Lebreton, Matthieu Schmidt, Maharajah Ponnaiah, Thierry Folliguet, Marylou Para, Julien Guihaire, Emmanuel Lansac, Edouard Sage, Bernard Cholley, Bruno Mégarbane, Pierrick Cronier, Jonathan Zarka, Daniel Da Silva, Sebastien Besset, Tristan Morichau-Beauchant, Igor Lacombat, Nicolas Mongardon, Christian Richard, Jacques Duranteau, Charles Cerf, Gabriel Saiydoun, Romain Sonneville, Jean-Daniel Chiche, Patrick Nataf, Dan Longrois, Alain Combes, Pascal Leprince, Charles JUVIN, Thibault SCHOELL, Cosimo D'Alessandro, Sofica MARIN, Nathalie NARDONE, Pierre DEMONDION, Horacio MEYER, Karl BOUNADER, Alexander MOIROUX, Ali AKAMKAM, Guillaume FADEL, Erwan RANDRIANALISOA, Sébastien CUSQUEL, Patrice LE GLOAHEC, Elisabeth HIRSCHAUER, Fabrice MUSQUET, Pierre-Marie Jego, Hélène Guedes, Théophile Roy, Lina Mercereau, Emmanuel Corvol, Anne Laboure, Flore Vilanove, Marco Peperoni, Dariène Machado, Aly Sely, Marion Fortanier, Séverine Gantois, Emilie Tran, Elisabeth Bosq, Aurélie Fontanier, Alice Morin, Jocelyne Cousin, Stéphanie Bovagnet, Charles Edouard Luyt, Guillaume Hekimian, Nicolas Brechot, Marc Pineton de Chambrun, Cyrielle Desnos, Juliette Chomeloux, Jeremy Arzoine, Emmanuelle Guerin, Antoine Monsel, Guillaume Voiriot, David Levy, Elodie Baron, Alexandra Beurton, Juliette Chommeloux, Meng Paris, Safaa Nemlaghi, Pierre Bay, Alexandre Demoule, Bertrand Guidet, Jean Michel Constantin, Muriel Fartoukh, Martin Dres, Guillaume Franchineau, Lucie Le Fevre, Richard Raffoul, Soleiman Alkhoder, Walid Ghodbane, Angelo Pisani, Wael Braham, Ali Bessem Gara, Pierre MORDANT, Yves-Hervé CASTIER, Etienne de MONTMOLLIN, Lila BOUADMA, Jean-François TIMSIT, Olivier Langeron, Quentin de Roux, Claire Alessandri, Margot Arminot-Frémaux, Simon Clariot, Thomas Dessalle, Agathe Kudela, André Ly, Arnaud Meffert, Elena Skripkina, Antonio Fiore, Costin Radu, Eleonora Dupuy-Montbrun, Christian Latremouille, Olaf Mercier, Philippe Deleuze, François STEPHAN, Marie Werner, Jean-Louis Teboul, Xavier Monnet, Hassan Debbagh, Alain Chapelier, Julien De Wolf, Matthieu Glorion, Ciprian Pricopi, Francesco Cassiano, Sébastien Jacquemin, Guillaume Tachon, François Parquin, Benjamin Zuber, Alain Carriou, Jean-Paul Mira, Julien Charpentier, Frederic Pene, Lee Nguyen, Sébastian Voicu, Nicolas Deye, Isabelle Malissin, Laetitia Sutterlin, Giulia Naim, Adrien Pépin-Lehalleur, Aymen Mrad, Jean-Michel Ekhérian, Philippe Nguyen, Georgios Sidéris, Dominique Vodovar, Caroline Grant, Mattéo Arcelli, Alban Copie, Zaccaria Errabih, Antoine Gonde, Adèle Magalhaes, Edouard Meurisse, Kiyoko Nitenberg, Arthur Perault, Lucile Perrin, Maxime Renaux, Sophie Marqué, Luis Ensenyat-Martin, Eric Delpierre, Matthieu Duprey, Daniel da Silva, Bruno Verdière, Julien Amour, Marina Clément, Yves Ollivier, Fabrice Daviaud, Camille Le Breton, Santiago Freita-Ramos, Marc Amouretti, Pierre Antoine Billiet, Myriam Dao, Louis Marie Dumont, Laura Federici, Baptiste Gaborieau, Pierre Postel-Vinay, Constance Vuillard, Noémie Zucman, Didier Dreyfuss, Jean Damien Ricard, Damien Roux, Unité de Recherche sur les Maladies Cardiovasculaires, du Métabolisme et de la Nutrition = Research Unit on Cardiovascular and Metabolic Diseases [IHU ICAN], Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Sorbonne Université (SU)-Institut de Cardiométabolisme et Nutrition = Institute of Cardiometabolism and Nutrition [CHU Pitié Salpêtrière] (IHU ICAN), CHU Pitié-Salpêtrière [AP-HP], Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Sorbonne Université (SU)-Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Sorbonne Université (SU)-CHU Pitié-Salpêtrière [AP-HP], Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Sorbonne Université (SU), Hôpital Henri Mondor, Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Hôpital Henri Mondor-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12), Laboratoire de Recherche Vasculaire Translationnelle (LVTS (UMR_S_1148 / U1148)), Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Paris Cité (UPCité)-Université Sorbonne Paris Nord, AP-HP - Hôpital Bichat - Claude Bernard [Paris], Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP), Hôpital Marie-Lannelongue, Institut Mutualiste de Montsouris (IMM), Hôpital Foch [Suresnes], Hôpital Européen Georges Pompidou [APHP] (HEGP), Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Hôpitaux Universitaires Paris Ouest - Hôpitaux Universitaires Île de France Ouest (HUPO), Service de Réanimation Médicale et Toxicologique [Hôpital Lariboisière], Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Hôpital Lariboisière-Fernand-Widal [APHP], Optimisation thérapeutique en Neuropsychopharmacologie (OPTeN (UMR_S_1144 / U1144)), Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Paris Cité (UPCité), Centre Hospitalier Sud Francilien, Centre hospitalier est francilien, Hôpital Delafontaine, Centre Hospitalier de Saint-Denis [Ile-de-France], Hôpital Louis Mourier - AP-HP [Colombes], Centre cardiologique du Nord (CCN), Hôpital Privé Jacques Cartier [Massy], AP-HP Hôpital Bicêtre (Le Kremlin-Bicêtre), Hôpital Cochin [AP-HP], Paris ECMO-COVID-19 investigators, Mégarbane, Bruno, and Unité de Recherche sur les Maladies Cardiovasculaires, du Métabolisme et de la Nutrition = Research Unit on Cardiovascular and Metabolic Diseases (ICAN)
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Male ,ARDS ,medicine.medical_treatment ,Corrections ,[SDV.MHEP.PSR]Life Sciences [q-bio]/Human health and pathology/Pulmonology and respiratory tract ,Cohort Studies ,0302 clinical medicine ,[SDV.MHEP.MI]Life Sciences [q-bio]/Human health and pathology/Infectious diseases ,Fraction of inspired oxygen ,score ,support: volume ,Renal Insufficiency ,030212 general & internal medicine ,[SDV.MHEP.ME] Life Sciences [q-bio]/Human health and pathology/Emerging diseases ,Respiratory Distress Syndrome ,[SDV.MHEP.ME]Life Sciences [q-bio]/Human health and pathology/Emerging diseases ,ecmo covid-19 ,Articles ,Middle Aged ,[SDV.MHEP.CSC] Life Sciences [q-bio]/Human health and pathology/Cardiology and cardiovascular system ,Pulmonary embolism ,[SDV.TOX] Life Sciences [q-bio]/Toxicology ,Intensive Care Units ,Outcome and Process Assessment, Health Care ,surgical procedures, operative ,[SDV.TOX]Life Sciences [q-bio]/Toxicology ,[SDV.MHEP.MI] Life Sciences [q-bio]/Human health and pathology/Infectious diseases ,Female ,France ,Cohort study ,Pulmonary and Respiratory Medicine ,medicine.medical_specialty ,03 medical and health sciences ,Extracorporeal Membrane Oxygenation ,[SDV.MHEP.CSC]Life Sciences [q-bio]/Human health and pathology/Cardiology and cardiovascular system ,Intensive care ,medicine ,Extracorporeal membrane oxygenation ,Humans ,Renal replacement therapy ,SARS-CoV-2 ,Septic shock ,business.industry ,COVID-19 ,medicine.disease ,Survival Analysis ,030228 respiratory system ,Emergency medicine ,[SDV.MHEP.PSR] Life Sciences [q-bio]/Human health and pathology/Pulmonology and respiratory tract ,Pulmonary Embolism ,business - Abstract
Erratum inCorrection to Lancet Respir Med 2021; published online April 19. https://doi.org/10.1016/S2213-2600(21)00096-5.; International audience; Background: In the Île-de-France region (henceforth termed Greater Paris), extracorporeal membrane oxygenation (ECMO) for severe acute respiratory distress syndrome (ARDS) was considered early in the COVID-19 pandemic. We report ECMO network organisation and outcomes during the first wave of the pandemic.Methods: In this multicentre cohort study, we present an analysis of all adult patients with laboratory-confirmed SARS-CoV-2 infection and severe ARDS requiring ECMO who were admitted to 17 Greater Paris intensive care units between March 8 and June 3, 2020. Central regulation for ECMO indications and pooling of resources were organised for the Greater Paris intensive care units, with six mobile ECMO teams available for the region. Details of complications (including ECMO-related complications, renal replacement therapy, and pulmonary embolism), clinical outcomes, survival status at 90 days after ECMO initiation, and causes of death are reported. Multivariable analysis was used to identify pre-ECMO variables independently associated with 90-day survival after ECMO.Findings: The 302 patients included who underwent ECMO had a median age of 52 years (IQR 45-58) and Simplified Acute Physiology Score-II of 40 (31-56), and 235 (78%) of whom were men. 165 (55%) were transferred after cannulation by a mobile ECMO team. Before ECMO, 285 (94%) patients were prone positioned, median driving pressure was 18 cm H2O (14-21), and median ratio of the partial pressure of arterial oxygen to the fraction of inspired oxygen was 61 mm Hg (IQR 54-70). During ECMO, 115 (43%) of 270 patients had a major bleeding event, 27 of whom had intracranial haemorrhage; 130 (43%) of 301 patients received renal replacement therapy; and 53 (18%) of 294 had a pulmonary embolism. 138 (46%) patients were alive 90 days after ECMO. The most common causes of death were multiorgan failure (53 [18%] patients) and septic shock (47 [16%] patients). Shorter time between intubation and ECMO (odds ratio 0·91 [95% CI 0·84-0·99] per day decrease), younger age (2·89 [1·41-5·93] for ≤48 years and 2·01 [1·01-3·99] for 49-56 years vs ≥57 years), lower pre-ECMO renal component of the Sequential Organ Failure Assessment score (0·67, 0·55-0·83 per point increase), and treatment in centres managing at least 30 venovenous ECMO cases annually (2·98 [1·46-6·04]) were independently associated with improved 90-day survival. There was no significant difference in survival between patients who had mobile and on-site ECMO initiation.Interpretation: Beyond associations with similar factors to those reported on ECMO for non-COVID-19 ARDS, 90-day survival among ECMO-assisted patients with COVID-19 was strongly associated with a centre's experience in venovenous ECMO during the previous year. Early ECMO management in centres with a high venovenous ECMO case volume should be advocated, by applying centralisation and regulation of ECMO indications, which should also help to prevent a shortage of resources.
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- 2021
6. Centromere strength: just a sense of proportion
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Marie Dumont, Daniele Fachinetti, and Institut Curie [Paris]
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0301 basic medicine ,Cancer Research ,Cell division ,[SDV]Life Sciences [q-bio] ,Aneuploidy ,Biology ,medicine.disease ,Chromosome segregation ,03 medical and health sciences ,chemistry.chemical_compound ,030104 developmental biology ,0302 clinical medicine ,chemistry ,Evolutionary biology ,Centromere ,medicine ,Author’s Views ,Molecular Medicine ,10. No inequality ,Mitosis ,ComputingMilieux_MISCELLANEOUS ,030217 neurology & neurosurgery ,DNA - Abstract
The overall structure and composition of human centromeres have been well reported, but how these elements vary between individual chromosomes and influence the chromosome-specific behavior during mitosis remains untested. In our study, we discover the existence of heterogeneity of centromeric DNA features that dictates the chromosome segregation fidelity during mitosis.
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- 2020
7. CENP-A overexpression promotes distinct fates in human cells, depending on p53 status
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Geneviève Almouzni, Katrina Podsypanina, Charlène Renaud-Pageot, Daniele Fachinetti, Daniel Jeffery, Lorraine Bonneville, Marie Dumont, Rebeca Ponce Landete, Alberto Gatto, Institut Curie [Paris], Université Paris sciences et lettres (PSL), Centre National de la Recherche Scientifique (CNRS), and Sorbonne Université (SU)
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0301 basic medicine ,Senescence ,QH301-705.5 ,[SDV]Life Sciences [q-bio] ,Cell ,Medicine (miscellaneous) ,macromolecular substances ,Biology ,Cell fate determination ,General Biochemistry, Genetics and Molecular Biology ,Article ,law.invention ,Cell-cycle exit ,03 medical and health sciences ,0302 clinical medicine ,law ,medicine ,Humans ,Epigenetics ,RNA-Seq ,Biology (General) ,Centromeres ,Epithelial-mesenchymal transition ,3. Good health ,Chromatin ,Cell biology ,Cancer therapeutic resistance ,030104 developmental biology ,medicine.anatomical_structure ,Gene Expression Regulation ,030220 oncology & carcinogenesis ,Suppressor ,Single-Cell Analysis ,Tumor Suppressor Protein p53 ,General Agricultural and Biological Sciences ,Reprogramming ,Function (biology) ,Centromere Protein A - Abstract
Tumour evolution is driven by both genetic and epigenetic changes. CENP-A, the centromeric histone H3 variant, is an epigenetic mark that directly perturbs genetic stability and chromatin when overexpressed. Although CENP-A overexpression is a common feature of many cancers, how this impacts cell fate and response to therapy remains unclear. Here, we established a tunable system of inducible and reversible CENP-A overexpression combined with a switch in p53 status in human cell lines. Through clonogenic survival assays, single-cell RNA-sequencing and cell trajectory analysis, we uncover the tumour suppressor p53 as a key determinant of how CENP-A impacts cell state, cell identity and therapeutic response. If p53 is functional, CENP-A overexpression promotes senescence and radiosensitivity. Surprisingly, when we inactivate p53, CENP-A overexpression instead promotes epithelial-mesenchymal transition, an essential process in mammalian development but also a precursor for tumour cell invasion and metastasis. Thus, we uncover an unanticipated function of CENP-A overexpression to promote cell fate reprogramming, with important implications for development and tumour evolution., Jeffery et al. develop a system of inducible and reversible CENP-A overexpression, combined with a switch in p53 status in human cell lines. They find the tumor suppressor p53 as a key determinant of how CENP-A impacts cell state, cell identity and therapeutic response. This study suggests that CENP-A overexpression promotes the reprogramming of cell fates in the context of tumor evolution.
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- 2020
8. Impact of Mandatory Wake Time on Sleep Timing, Sleep Quality and Rest-Activity Cycle in College and University Students Complaining of a Delayed Sleep Schedule: An Actigraphy Study
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Marie Dumont, Solenne Van der Maren, Jean Paquet, and Christophe Moderie
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medicine.medical_specialty ,circadian sleep disorders ,ambulatory recordings ,Audiology ,Bedtime ,social jetlag ,03 medical and health sciences ,Behavioral Neuroscience ,delayed sleep-wake phase disorder ,0302 clinical medicine ,Nature and Science of Sleep ,medicine ,Applied Psychology ,Morning ,Sleep scheduling ,Original Research ,business.industry ,Chronotype ,sleep schedule ,Actigraphy ,Alertness ,030228 respiratory system ,chronotype ,Sleep diary ,Sleep (system call) ,business ,030217 neurology & neurosurgery - Abstract
Christophe Moderie,1,2 Solenne Van der Maren,1,3 Jean Paquet,1 Marie Dumont1,4 1Center for Advanced Research in Sleep Medicine, Sacre-Coeur Hospital, CIUSSS-NIM, Montreal, Quebec, Canada; 2Department of Psychiatry, McGill University, Montreal, Quebec, Canada; 3Department of Psychology, University of Montreal, Montreal, Quebec, Canada; 4Department of Psychiatry, University of Montreal, Montreal, Quebec, CanadaCorrespondence: Marie DumontCenter for Advanced Research in Sleep Medicine (J-5185), Sacre-Coeur Hospital of Montreal, CIUSSS-NIM, 5400 Boul. Gouin Ouest, Montreal, QC H4J 1C5, CanadaTel +1 514 338 2222, x-2246Fax +1 514 338 2531Email Marie.dumont@umontreal.caBackground: Individuals complaining of a delayed sleep schedule are expected to have shorter sleep duration and lower sleep quality when they must comply with morning obligations. The changes in the sleep schedule imposed by morning obligations may in turn decrease the stability and amplitude of their rest-activity cycle. These expectations were only partially supported in previous studies, possibly due to poor differentiation between days with mandatory or free wake times.Participants: Fourteen college/university students (8 women) with a complaint of a late sleep schedule and a bedtime after midnight were compared to fourteen controls with an earlier sleep schedule and no complaint.Methods: During a week of 24-h activity recording, participants specified in their sleep diary whether their wake time was free or determined by an obligation.Results: The number of nights with mandatory wake times was similar in the two groups. Groups were also similar for sleep duration and sleep quality over the 7 days of recording. Actigraphic sleep efficiency was the same in the two groups for both free and mandatory wake times, but subjective sleep quality decreased on the nights with mandatory wake time in both groups. On the nights with mandatory wake time, delayed participants had shorter sleep episodes and less total sleep time than controls. Rest-activity cycle amplitude was lower in the delayed group whether wake time was free or mandatory.Conclusion: Sleep duration and total sleep time differed between the two groups only when wake time was mandatory. Prior to mandatory wake times, delayed participants kept the same bedtime and shortened their sleep; sleep latency and sleep efficiency were preserved but subjective sleep quality and alertness on awakening decreased compared to nights with free wake time. Lower amplitude of the rest-activity cycle in delayed subjects may reflect lifestyle differences compared to control participants.Keywords: sleep schedule, circadian sleep disorders, chronotype, ambulatory recordings, delayed sleep-wake phase disorder, social jetlag
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- 2020
9. Increased risk of permanent stoma in Crohn's disease associated with hidradenitis suppurativa: a case-control study
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Sarah Guégan, Harry Sokol, Philippe Seksik, Jacques Cosnes, Cécilia Landman, Louis-Marie Dumont, and Laurent Beaugerie
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Adult ,Male ,medicine.medical_specialty ,Disease ,Gastroenterology ,Inflammatory bowel disease ,Stoma ,03 medical and health sciences ,Young Adult ,0302 clinical medicine ,Crohn Disease ,Risk Factors ,Internal medicine ,medicine ,Odds Ratio ,Prevalence ,Humans ,Pharmacology (medical) ,Hidradenitis suppurativa ,030212 general & internal medicine ,Risk factor ,Retrospective Studies ,Crohn's disease ,Hepatology ,business.industry ,Tumor Necrosis Factor-alpha ,Case-control study ,Odds ratio ,medicine.disease ,Prognosis ,Hidradenitis Suppurativa ,Case-Control Studies ,030211 gastroenterology & hepatology ,Female ,business - Abstract
BACKGROUND Crohn's disease (CD) and hidradenitis suppurativa (HS), a chronic inflammatory skin disease, induce similar inflammatory lesions of the groin and gluteal area. Both diseases are characterised by an inadequate immune response to commensal bacteria in genetically predisposed subjects and can be associated. AIM To assess whether HS was associated with clinical and prognostic factors in CD. METHODS A retrospective case-control study included 4645 patients with CD referred to Saint-Antoine Hospital gastroenterology tertiary care centre between 2003 and 2016. Matching variables were sex, age, age and the presence of perianal lesions at CD diagnosis, follow-up quality. HS was confirmed by dermatological examination; location, phenotype and severity (Hurley staging) were recorded. RESULTS Hidradenitis suppurativa prevalence was 0.95% (44 cases); 80% of patients displayed Hurley stage II or III disease. CD preceded HS in 70% of cases with a median interval of 9 years (IQR 5.25-12.75). CD with HS was more active (56% vs 40% years with active disease, P
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- 2020
10. Human chromosome‐specific aneuploidy is influenced by <scp>DNA</scp> ‐dependent centromeric features
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Joseph T Worrall, Pierre Gestraud, Sippe G. de Vries, Sarah E. McClelland, Catalina Salinas‐Luypaert, Karen H. Miga, Susanne M.A. Lens, Vincent Boudreau, Paul S. Maddox, Geert J. P. L. Kops, Daniele Fachinetti, Marie Dumont, Riccardo Gamba, Sjoerd Klaasen, Hubrecht Institute for Developmental Biology and Stem Cell Research, Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), Institut Curie [Paris], Department of Biology [Chapel Hill, NC, USA], University of North Carolina [Chapel Hill] (UNC), and University of North Carolina System (UNC)-University of North Carolina System (UNC)
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Male ,[SDV]Life Sciences [q-bio] ,Centromere ,Aneuploidy ,Biology ,General Biochemistry, Genetics and Molecular Biology ,Chromosome segregation ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Chromosome Segregation ,medicine ,Chromosomes, Human ,Humans ,Repeated sequence ,Molecular Biology ,Cells, Cultured ,ComputingMilieux_MISCELLANEOUS ,030304 developmental biology ,0303 health sciences ,General Immunology and Microbiology ,General Neuroscience ,Chromosome ,Articles ,DNA ,medicine.disease ,Chromatin ,chemistry ,Evolutionary biology ,Female ,Centromere Protein A ,030217 neurology & neurosurgery ,Function (biology) - Abstract
Intrinsic genomic features of individual chromosomes can contribute to chromosome-specific aneuploidy. Centromeres are key elements for the maintenance of chromosome segregation fidelity via a specialized chromatin marked by CENP-A wrapped by repetitive DNA. These long stretches of repetitive DNA vary in length among human chromosomes. Using CENP-A genetic inactivation in human cells, we directly interrogate if differences in the centromere length reflect the heterogeneity of centromeric DNA-dependent features and whether this, in turn, affects the genesis of chromosome-specific aneuploidy. Using three distinct approaches, we show that mis-segregation rates vary among different chromosomes under conditions that compromise centromere function. Whole-genome sequencing and centromere mapping combined with cytogenetic analysis, small molecule inhibitors, and genetic manipulation revealed that inter-chromosomal heterogeneity of centromeric features, but not centromere length, influences chromosome segregation fidelity. We conclude that faithful chromosome segregation for most of human chromosomes is biased in favor of centromeres with high abundance of DNA-dependent centromeric components. These inter-chromosomal differences in centromere features can translate into non-random aneuploidy, a hallmark of cancer and genetic diseases.
- Published
- 2019
11. Daily Profiles of Light Exposure and Evening Use of Light-emitting Devices in Young Adults Complaining of a Delayed Sleep Schedule
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Jean Paquet, Véronique Daneault, Solenne Van der Maren, Marie Dumont, Christophe Moderie, and Catherine Duclos
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Adult ,Male ,0301 basic medicine ,Evening ,Adolescent ,Light ,Physiology ,Photoperiod ,Bedtime ,Melatonin ,Young Adult ,03 medical and health sciences ,0302 clinical medicine ,Sleep Disorders, Circadian Rhythm ,Physiology (medical) ,Humans ,Medicine ,Circadian rhythm ,Young adult ,Saliva ,Lighting ,Sleep scheduling ,Computers ,business.industry ,Chronotype ,Circadian Rhythm ,030104 developmental biology ,Before Bedtime ,Female ,business ,030217 neurology & neurosurgery ,medicine.drug - Abstract
A number of factors can contribute to a delayed sleep schedule. An important factor could be a daily profile of light exposure favoring a later circadian phase. This study aimed to compare light exposure between 14 young adults complaining of a delayed sleep schedule and 14 matched controls and to identify possible associations between habitual light exposure and circadian phase. Exposure to white and blue light was recorded with ambulatory monitors for 7 consecutive days. Participants also noted their daily use of light-emitting devices before bedtime. Endogenous circadian phase was estimated with the dim light melatonin onset (DLMO) in the laboratory. The amplitude of the light-dark cycle to which the subjects were exposed was smaller in delayed than in control subjects, and smaller amplitude was associated with a later DLMO. Smaller amplitude was due to both decreased exposure in the daytime and increased exposure at night. Total exposure to blue light, but not to white light, was lower in delayed subjects, possibly due to lower exposure to blue-rich outdoor light. Lower daily exposure to blue light was associated with a later DLMO. Timing of relative increases and decreases of light exposure in relation to endogenous circadian phase was also compared between the 2 groups. In delayed subjects, there was a relatively higher exposure to white and blue light 2 h after DLMO, a circadian time with maximal phase-delaying effect. Delayed participants also had higher exposure to light 8 to 10 h after DLMO, which occurred mostly during their sleep episode but may have some phase-advancing effects. Self-reported use of light-emitting devices before bedtime was higher in delayed than in control subjects and was associated with a later DLMO. This study suggests that individuals complaining of a delayed sleep schedule engage in light-related behaviors favoring a later circadian phase and a later bedtime.
- Published
- 2018
12. Sleep-wake disturbances in hospitalized patients with traumatic brain injury: association with brain trauma but not with an abnormal melatonin circadian rhythm
- Author
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David K. Menon, Nadia Gosselin, Hélène Blais, Solenne Van der Maren, Francis Bernard, Catherine Duclos, Jean Paquet, Marie Dumont, Université de Montréal. Faculté des arts et des sciences. Département de psychologie, Menon, David [0000-0002-3228-9692], and Apollo - University of Cambridge Repository
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Adult ,Male ,Sleep Wake Disorders ,Traumatic brain injury ,Polysomnography ,Urinary system ,Circadian clock ,Acute care ,Urine ,Neurological Disorders ,Melatonin ,Excretion ,Young Adult ,03 medical and health sciences ,0302 clinical medicine ,Circadian Clocks ,Physiology (medical) ,Brain Injuries, Traumatic ,medicine ,Humans ,Circadian rhythms ,Circadian rhythm ,business.industry ,030208 emergency & critical care medicine ,Actigraphy ,Middle Aged ,medicine.disease ,Circadian Rhythm ,nervous system diseases ,nervous system ,Brain Injuries ,Anesthesia ,Female ,Neurology (clinical) ,business ,Sleep ,030217 neurology & neurosurgery ,medicine.drug - Abstract
Study Objectives To test whether the sleep-wake cycle disruption in patients hospitalized with traumatic brain injury (TBI) (1) is also found in patients with traumatic injuries other than TBI (non-TBI) and (2) is associated with a weaker or abnormal circadian clock signal. Methods Forty-two non-mechanically ventilated and non-sedated patients hospitalized for moderate-to-severe TBI were compared to 34 non-TBI patients. They wore wrist actigraphs for 9.4 ± 4.2 days, starting 19.3 ± 12.6 days post-injury. Of these, 17 TBI and 14 non-TBI patients had their urine collected every hour for 25 hours, starting 18.3 ± 12.3 days post-injury. We calculated urinary 6-sulfatoxymelatonin concentration to obtain total 24-hour excretion, excretion onset, offset, duration, amplitude, and acrophase. Using Student’s t-tests, we compared groups on actigraphy (daytime activity ratio, nighttime total sleep time, and fragmentation index) and melatonin variables. We investigated associations between melatonin and actigraphy variables using Pearson’s correlations. Results TBI patients had poorer daytime activity ratio (TBI: 77.5 ± 9.4%; non-TBI: 84.6 ± 6.9%), shorter nighttime total sleep time (TBI: 353.5 ± 96.6 min; non-TBI: 421.2 ± 72.2 min), and higher fragmentation index (TBI: 72.2 ± 30.0; non-TBI: 53.5 ± 23.6) (all p-values < 0.01). A melatonin rhythm was present in both groups, and no group differences were found on melatonin variables. No associations were found between melatonin and actigraphy variables in TBI patients. Conclusion Moderate-to-severe TBI patients have more serious sleep-wake disturbances than non-TBI patients hospitalized in the same environment, suggesting that the brain injury itself alters the sleep-wake cycle. Despite their deregulated 24-hour sleep-wake cycle, TBI patients have a normal circadian clock signal.
- Published
- 2019
13. Plasticity in the Sensitivity to Light in Aging: Decreased Non-visual Impact of Light on Cognitive Brain Activity in Older Individuals but No Impact of Lens Replacement
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Véronique Daneault, Marie Dumont, Éric Massé, Pierre Forcier, Arnaud Boré, Jean-Marc Lina, Julien Doyon, Gilles Vandewalle, and Julie Carrier
- Subjects
cognition ,0301 basic medicine ,Melanopsin ,medicine.medical_specialty ,lens ,genetic structures ,Physiology ,Brain activity and meditation ,medicine.medical_treatment ,Intraocular lens ,Audiology ,lcsh:Physiology ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Physiology (medical) ,medicine ,non-visual impact of light ,Circadian rhythm ,Original Research ,lcsh:QP1-981 ,business.industry ,aging ,Retinal ,Cognition ,Cataract surgery ,eye diseases ,Alertness ,circadian ,030104 developmental biology ,chemistry ,light ,business ,melanopsin ,030217 neurology & neurosurgery - Abstract
Beyond its essential visual role, light, and particularly blue light, has numerous non-visual effects, including stimulating cognitive functions and alertness. Non-visual effects of light may decrease with aging and contribute to cognitive and sleepiness complaints in aging. However, both the brain and the eye profoundly change in aging. Whether the stimulating effects light on cognitive brain functions varies in aging and how ocular changes may be involved is not established. We compared the impact of blue and orange lights on non-visual cognitive brain activity in younger (23.6 ± 2.5 years), and older individuals with their natural lenses (NL; 66.7 ± 5.1 years) or with intraocular lens (IOL) replacement following cataract surgery (69.6 ± 4.9 years). Analyses reveal that blue light modulates executive brain responses in both young and older individuals. Light effects were, however, stronger in young individuals including in the hippocampus and frontal and cingular cortices. Light effects did not significantly differ between older-IOL and older-NL while regression analyses indicated that differential brain engagement was not underlying age-related differences in light effects. These findings show that, although its impact decreases, light can stimulate cognitive brain activity in aging. Since lens replacement did not affect light impact, the brain seems to adapt to the progressive decrease in retinal light exposure in aging.
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- 2018
14. Amplitude of the rest–activity cycle in chronic obstructive pulmonary disease: an exploratory study
- Author
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Jean Paquet, Barbara Trutschnigg, Gregory Moullec, Zohra Parwanta, Véronique Pepin, Emilie Chan-Thim, and Marie Dumont
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education.field_of_study ,COPD ,medicine.medical_specialty ,Rehabilitation ,business.industry ,medicine.medical_treatment ,Population ,Actigraphy ,General Medicine ,Disease ,medicine.disease ,Pulmonary function testing ,03 medical and health sciences ,0302 clinical medicine ,Amplitude ,Rhythm ,030228 respiratory system ,Internal medicine ,medicine ,Physical therapy ,Cardiology ,education ,business ,030217 neurology & neurosurgery - Abstract
In chronic obstructive pulmonary disease (COPD), there is large individual variability in the progression of the disease. Low amplitude of rest–activity rhythms has been associated with worse prognosis in a variety of diseases, but it has not been investigated in COPD. The first aim of this exploratory study was to compare disease severity and prognosis indicators between COPD patients with relatively high or low amplitude of their rest–activity cycle, as measured with actigraphy. As a second objective, 24-hour profiles of both activity levels and nighttime-sleep quality were compared between the two subgroups to assess the relative contribution of day- and night-activity levels to high and low rest–activity rhythm amplitude in this population. Rest–activity rhythms were measured with 8–14 days of wrist actigraphy in 14 patients (nine men), aged 58–79 years, suffering from moderate-to-severe COPD. Relative amplitude of 24-hour activity profiles ranged from 0.72 to 0.98. Participants were divided at the median into high-amplitude (mean ± standard deviation 0.9±0.04) and low-amplitude (0.79±0.05) subgroups. There was no significant difference between the two subgroups for pulmonary function or exercise capacity. However, the low-amplitude group had more severe symptoms of dyspnea and worse prognostic scores than the high-amplitude group (P
- Published
- 2016
15. A 10 year record of black carbon and dust from a Mera Peak ice core (Nepal): variability and potential impact on melting of Himalayan glaciers
- Author
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Paolo Bonasoni, Jean-Denis Taupin, Yves Arnaud, Nicolas Patris, Adrien Gilbert, Patrick Wagnon, P. Laj, Marie Dumont, S. Lim, Angela Marinoni, Patrick Ginot, Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), Laboratoire de glaciologie et géophysique de l'environnement (LGGE), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Hydrosciences Montpellier (HSM), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d’étude des Transferts en Hydrologie et Environnement (LTHE), CNR Institute of Atmospheric Sciences and Climate (ISAC), Consiglio Nazionale delle Ricerche (CNR), National Research Council, Institue of Atmospheric Sciences and Climate, Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'étude des transferts en hydrologie et environnement (LTHE), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique de Grenoble (INPG)-Centre National de la Recherche Scientifique (CNRS), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Météo France-Centre National de la Recherche Scientifique (CNRS), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS), and Institut de Recherche pour le Développement (IRD)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
010504 meteorology & atmospheric sciences ,[SDE.MCG]Environmental Sciences/Global Changes ,[SDU.STU]Sciences of the Universe [physics]/Earth Sciences ,010501 environmental sciences ,Monsoon ,Atmospheric sciences ,01 natural sciences ,Ice core ,medicine ,Precipitation ,[SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment ,ComputingMilieux_MISCELLANEOUS ,lcsh:Environmental sciences ,0105 earth and related environmental sciences ,Earth-Surface Processes ,Water Science and Technology ,[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere ,lcsh:GE1-350 ,geography ,geography.geographical_feature_category ,lcsh:QE1-996.5 ,Glacier ,15. Life on land ,Seasonality ,Albedo ,medicine.disease ,Snow ,lcsh:Geology ,Deposition (aerosol physics) ,13. Climate action ,Climatology ,Environmental science - Abstract
A shallow ice core was extracted at the summit of Mera Peak at 6376 m a.s.l. in the southern flank of the Nepalese Himalaya range. From this core, we reconstructed the seasonal deposition fluxes of dust and refractory black carbon (rBC) since 1999. This archive presents well preserved seasonal cycles based on a monsoonal precipitation pattern. According to the seasonal precipitation regime in which 80% of annual precipitation falls between June and September, we estimated changes in the concentrations of these aerosols in surface snow. The analyses revealed that mass fluxes are a few orders of magnitude higher for dust (10.4 ± 2.8 g m−2 yr−1 than for rBC (7.9 ± 2.8 mg m−2 yr−1). The relative lack of seasonality in the dust record may reflect a high background level of dust inputs, whether from local or regional sources. Over the 10-year record, no deposition flux trends were detected for any of the species of interest. The data were then used to simulate changes in the surface snow albedo over time and the potential melting caused by these impurities. Mean potential melting caused by dust and rBC combined was 713 kg m−2 yr−1, and for rBC alone, 342 kg m−2 yr−1 for rBC under certain assumptions. Compared to the melting rate measured using the mass and energy balance at 5360 m a.s.l. on Mera Glacier between November 2009 and October 2010, i.e. 3000 kg m−2 yr−1 and 3690 kg m−2 yr−1 respectively, the impact of rBC represents less than 16% of annual potential melting while the contribution of dust and rBC combined to surface melting represents a maximum of 26%. Over the 10-year period, rBC variability in the ice core signal primarily reflected variability of the monsoon signal rather than variations in the intensity of emissions.
- Published
- 2018
16. Sleep-wake cycle recovery after moderate to severe traumatic brain injury: are ultradian rhythms involved?
- Author
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Julie Carrier, David K. Menon, Marie Dumont, J. Daoust, Catherine Duclos, Jean-Marc Lina, Nathalie Gosselin, S. Van der Maren, Francis Bernard, and Hélène Blais
- Subjects
Moderate to severe ,Traumatic brain injury ,business.industry ,Anesthesia ,medicine ,General Medicine ,Circadian rhythm ,medicine.disease ,business ,Ultradian rhythm - Published
- 2019
17. Light modulates oscillatory alpha activity in the occipital cortex of totally visually blind individuals with intact non-visual photoreception
- Author
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Markus J. van Ackeren, Marie Dumont, Joseph T. Hull, Gilles Vandewalle, Franco Lepore, Julie Carrier, Olivier Collignon, Steven W. Lockley, Véronique Daneault, Julien Doyon, Charles A. Czeisler, and Geneviève Albouy
- Subjects
0303 health sciences ,genetic structures ,medicine.diagnostic_test ,Brain activity and meditation ,Intrinsically photosensitive retinal ganglion cells ,Cognition ,Electroencephalography ,Biology ,03 medical and health sciences ,Alertness ,0302 clinical medicine ,medicine.anatomical_structure ,Rhythm ,Cortex (anatomy) ,medicine ,Circadian rhythm ,Neuroscience ,030217 neurology & neurosurgery ,030304 developmental biology - Abstract
The discovery of intrinsically photosensitive retinal ganglion cells (ipRGCs) marked a major shift in our understanding of how light is processed by the mammalian brain. These ipRGCs influence multiple functions not directly related to vision such as the synchronization of circadian rhythmicity, pupil constriction, the regulation of alertness and sleep, as well as the modulation of cognition. More recently, it was demonstrated that ipRGCs may also contribute to basic visual functions. The impact of ipRGCs on visual functions, independently of image forming photoreceptors, remains however difficult to isolate, particularly in humans. We previously showed that exposure to intense monochromatic blue light (465nm) induced awareness of light in a forced choice task in three rare totally visually blind individuals without detectable rod and cone function, but who retained non-visual responses to light, very likely via ipRGCs. The neural foundation of such light awareness in the absence of conscious vision is unknown, however. In this study, we characterized the brain activity of these three rare participants using electroencephalography (EEG), and demonstrate that unconsciously perceived light triggers an early and reliable transient desynchronization (i.e. decreased power) of the alpha EEG rhythm (8-14 Hz) over the occipital cortex. These results provide compelling insight into how ipRGC may contribute to transient changes in ongoing brain activity. They suggest that occipital alpha rhythm synchrony, which is typically linked to the visual system, is modulated by ipRGCs photoreception; a process that may contribute to the awareness of light in those blind individuals.
- Published
- 2017
18. Parallel recovery of consciousness and sleep in acute traumatic brain injury
- Author
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Jean Paquet, Francis Bernard, Catherine Duclos, Caroline Arbour, Louis De Beaumont, Marie Dumont, Nadia Gosselin, Hélène Blais, David K. Menon, Université de Montréal. Faculté des arts et des sciences. Département de psychologie, Menon, David [0000-0002-3228-9692], and Apollo - University of Cambridge Repository
- Subjects
Sleep Wake Disorders ,Adult ,Male ,030506 rehabilitation ,Adolescent ,Consciousness ,Traumatic brain injury ,Rancho Los Amigos Scale ,Article ,Young Adult ,03 medical and health sciences ,Cognition ,0302 clinical medicine ,Level of consciousness ,Activities of Daily Living ,Brain Injuries, Traumatic ,Humans ,Medicine ,Glasgow Coma Scale ,Young adult ,Retrospective Studies ,business.industry ,Actigraphy ,Recovery of Function ,medicine.disease ,Hospitalization ,Intensive Care Units ,Brain Injuries ,Anesthesia ,Acute Disease ,Female ,Memory consolidation ,Neurology (clinical) ,Sleep ,0305 other medical science ,business ,030217 neurology & neurosurgery - Abstract
Objective: To investigate whether the progressive recuperation of consciousness was associated with the reconsolidation of sleep and wake states in hospitalized patients with acute traumatic brain injury (TBI). Methods: This study comprised 30 hospitalized patients (age 29.1 6 13.5 years) in the acute phase of moderate or severe TBI. Testing started 21.0 6 13.7 days postinjury. Consciousness level and cognitive functioning were assessed daily with the Rancho Los Amigos scale of cognitive functioning (RLA). Sleep and wake cycle characteristics were estimated with continuous wrist actigraphy. Mixed model analyses were performed on 233 days with the RLA (fixed effect) and sleep-wake variables (random effects). Linear contrast analyses were performed in order to verify if consolidation of the sleep and wake states improved linearly with increasing RLA score. Results: Associations were found between scores on the consciousness/cognitive functioning scale and measures of sleep-wake cycle consolidation (p , 0.001), nighttime sleep duration (p 5 0.018), and nighttime fragmentation index (p , 0.001). These associations showed strong linear relationships (p , 0.01 for all), revealing that consciousness and cognition improved in parallel with sleep-wake quality. Consolidated 24-hour sleep-wake cycle occurred when patients were able to give context-appropriate, goal-directed responses. Conclusions: Our results showed that when the brain has not sufficiently recovered a certain level of consciousness, it is also unable to generate a 24-hour sleep-wake cycle and consolidated nighttime sleep. This study contributes to elucidating the pathophysiology of severe sleepwake cycle alterations in the acute phase of moderate to severe TBI., This study was supported by the Canadian Institutes of Health Research (grant no. 115172) and by the Fonds pour la Recherche du Québec–Santé (grant no. 24742).
- Published
- 2017
19. Circadian phase, dynamics of subjective sleepiness and sensitivity to blue light in young adults complaining of a delayed sleep schedule
- Author
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Christophe Moderie, Marie Dumont, and Solenne Van der Maren
- Subjects
0301 basic medicine ,Adult ,Male ,medicine.medical_specialty ,Evening ,Light ,Delayed sleep phase ,Enzyme-Linked Immunosorbent Assay ,Audiology ,Bedtime ,Melatonin ,03 medical and health sciences ,Young Adult ,0302 clinical medicine ,Dark therapy ,Sleep Disorders, Circadian Rhythm ,Internal medicine ,medicine ,Humans ,Circadian rhythm ,Saliva ,Light sensitivity ,General Medicine ,medicine.disease ,Sleep in non-human animals ,Circadian Rhythm ,030104 developmental biology ,Endocrinology ,Female ,Psychology ,Sleep ,030217 neurology & neurosurgery ,medicine.drug - Abstract
Objective To assess factors that might contribute to a delayed sleep schedule in young adults with sub-clinical features of delayed sleep phase disorder. Methods Two groups of 14 young adults (eight women) were compared: one group complaining of a delayed sleep schedule and a control group with an earlier bedtime and no complaint. For one week, each subject maintained a target bedtime reflecting their habitual sleep schedule. Subjects were then admitted to the laboratory for the assessment of circadian phase (dim light melatonin onset), subjective sleepiness, and non-visual light sensitivity. All measures were timed relative to each participant's target bedtime. Non-visual light sensitivity was evaluated using subjective sleepiness and salivary melatonin during 1.5-h exposure to blue light, starting one hour after target bedtime. Results Compared to control subjects, delayed subjects had a later circadian phase and a slower increase of subjective sleepiness in the late evening. There was no group difference in non-visual sensitivity to blue light, but we found a positive correlation between melatonin suppression and circadian phase within the delayed group. Conclusions Our results suggest that a late circadian phase, a slow build-up of sleep need, and an increased circadian sensitivity to blue light contribute to the complaint of a delayed sleep schedule. These findings provide targets for strategies aiming to decreasing the severity of a sleep delay and the negative consequences on daytime functioning and health.
- Published
- 2016
20. Rest-Activity Cycle Disturbances in the Acute Phase of Moderate to Severe Traumatic Brain Injury
- Author
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Catherine Duclos, David K. Menon, Marie Dumont, Catherine Wiseman-Hakes, Nadia Gosselin, Hélène Blais, Louis De Beaumont, Jean Paquet, Elyse Laflamme, Francis Bernard, and Université de Montréal. Faculté de médecine. Département de psychiatrie et d'addictologie
- Subjects
Activity Cycles ,Adult ,Male ,Sleep Wake Disorders ,Moderate to severe ,medicine.medical_specialty ,Adolescent ,Traumatic brain injury ,Neuropsychological Tests ,Young Adult ,Cognition ,Intensive care ,Brain Injuries, Traumatic ,Humans ,Medicine ,sleep ,intensive care ,Gynecology ,business.industry ,traumatic brain injury ,General Medicine ,Middle Aged ,Rest activity ,medicine.disease ,Actigraphy ,circadian rhythms ,Physical therapy ,Female ,business - Abstract
Background. Sleep-wake disturbances are among the most persistent sequelae after traumatic brain injury (TBI) and probably arise during the hospital stay following TBI. These disturbances are characterized by difficulties sleeping at night and staying awake during the day. Objective. The aim of the present study was to document rest-activity cycle consolidation in acute moderate/severe TBI using actigraphy and to assess its association with injury severity and outcome. Methods. In all, 16 hospitalized patients (27.1 ± 11.3 years) with moderate/severe TBI wore actigraphs for 10 days, starting in the intensive care unit (ICU) when continuous sedation was discontinued and patients had reached medical stability. Activity counts were summed for daytime (7:00-21:59 hours) and nighttime periods (22:00-6:59 hours). The ratio of daytime period activity to total 24-hour activity was used to quantify rest-activity cycle consolidation. An analysis of variance was carried out to characterize the evolution of the daytime activity ratio over the recording period. Results. Rest-activity cycle was consolidated only 46.6% of all days; however, a significant linear trend of improvement was observed over time. Greater TBI severity and longer ICU and hospital lengths of stay were associated with poorer rest-activity cycle consolidation and evolution. Patients with more rapid return to consolidated rest-activity cycle were more likely to have cleared posttraumatic amnesia and have lower disability at hospital discharge. Conclusions. Patients with acute moderate/severe TBI had an altered rest-activity cycle, probably reflecting severe fragmentation of sleep and wake episodes, which globally improved over time. A faster return to rest-activity cycle consolidation may predict enhanced brain recovery.
- Published
- 2013
21. An Adult Returned Traveler from Dubai Hospitalized with an Influenza-Like Illness (ILI): Middle East Respiratory Syndrome (MERS) or Influenza? Infection Control Implications from a Near MERS Case
- Author
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Marie Dumont, Burke A. Cunha, and Eileen Abruzzo
- Subjects
Microbiology (medical) ,medicine.medical_specialty ,Influenza-like illness ,Infectious Diseases ,Epidemiology ,business.industry ,Emergency medicine ,medicine ,Infection control ,Middle East respiratory syndrome ,Intensive care medicine ,business ,medicine.disease - Published
- 2015
22. Clinical Impact of Time of Day on Acute Exercise Response in COPD
- Author
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Amanda Rizk, Simon Parenteau, Gregory Moullec, Jean Paquet, Myriam de Lorimier, Véronique Pepin, Marie Dumont, Rima Wardini, Barbara Trutschnigg, and Emilie Chan-Thim
- Subjects
Male ,Pulmonary and Respiratory Medicine ,Spirometry ,medicine.medical_specialty ,Time Factors ,Pilot Projects ,Pulmonary function testing ,Incremental exercise ,Cohort Studies ,Pulmonary Disease, Chronic Obstructive ,FEV1/FVC ratio ,Forced Expiratory Volume ,Internal medicine ,medicine ,Humans ,Respiratory function ,Circadian rhythm ,Completely randomized design ,Aged ,COPD ,Exercise Tolerance ,medicine.diagnostic_test ,business.industry ,Middle Aged ,medicine.disease ,Circadian Rhythm ,Exercise Test ,Physical therapy ,Cardiology ,Female ,business - Abstract
The purpose of this pilot study was to determine the impact of time of day on the acute response to incremental exercise in chronic obstructive pulmonary disease (COPD). Fourteen subjects (nine men) aged 71 ± 7 years with moderate to severe airflow obstruction (FEV1: 58 ± 13% predicted) followed a counterbalanced randomized design, performing three symptom-limited incremental cycling tests at 8:00, 12:00, and 16:00 hours on different days, each preceded by a spirometry. COPD medications were withdrawn prior to testing. No overall time effect was found for peak exercise capacity (p = 0.22) or pulmonary function (FEV1, p = 0.56; FVC, p = 0.79). However, a large effect size (f = 0.48) was observed for peak exercise capacity and several pulmonary function parameters. For peak exercise capacity, the average within-subject coefficient of variation was 5.5 ± 3.9% and the average amplitude of change was 7 ± 5W. Seven subjects (50%) showed diurnal changes at levels equal to or beyond the minimal clinically important difference for both peak exercise capacity and pulmonary function. In this sub-group, peak exercise capacity was greatest at 16:00 hours (p = 0.03, ƒ = 1.04). No systematic time-of-day effect on peak exercise capacity was obtained in COPD patients in the present pilot study. However, based on the observed effect size and on the average amplitude of change and within-subject variations seen across testing times, the guidelines recommendation that time of day be standardized for repeat exercise testing in COPD should be maintained.
- Published
- 2013
23. Diurnal Variations in Psychological Distress in Chronic Obstructive Pulmonary Disease
- Author
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Gregory Moullec, Véronique Pepin, Marie Dumont, Amanda Rizk, Zohra Parwanta, and Emilie Chan-Thim
- Subjects
Male ,medicine.medical_specialty ,Evening ,Time Factors ,Psychometrics ,Physical Therapy, Sports Therapy and Rehabilitation ,Pilot Projects ,macromolecular substances ,03 medical and health sciences ,Pulmonary Disease, Chronic Obstructive ,0302 clinical medicine ,Internal medicine ,medicine ,Humans ,Clinical significance ,030212 general & internal medicine ,Prospective Studies ,General Nursing ,Depression (differential diagnoses) ,Morning ,Aged ,Aged, 80 and over ,COPD ,business.industry ,Depression ,Rehabilitation ,Diurnal temperature variation ,Quebec ,General Medicine ,Center for Epidemiologic Studies Depression Scale ,medicine.disease ,030228 respiratory system ,Physical therapy ,Observational study ,Female ,business ,Stress, Psychological - Abstract
Purpose: The aim of this study was to investigate the association between depressive symptoms severity and amplitude of diurnal variations in depression symptoms in patients with chronic obstructive pulmonary disease (COPD). Design: Prospective, observational proof-of-concept study. Methods: Fourteen participants with moderate/severe COPD completed a 20-item Center for Epidemiologic Studies Depression Scale (CES-D) estimating depressive symptoms severity. Throughout one week, the four-item very short version of the CES-D was completed every day in the morning, afternoon, and evening. Findings: Strong positive correlations were observed between depressive severity and the mean range of diurnal variations in positive (r = .61) and depressed affects (r = .67), somatic complaints (r = .82), and disturbed interpersonal relationships (r = .71). Conclusion: In COPD patients, a greater diurnal variation in depression symptoms was associated with greater depression severity. This relationship seems independent of COPD severity. Clinical Relevance: Diurnal variation in the symptoms of depression is a new method of identifying depression severity in COPD.
- Published
- 2016
24. Plant cell wall imaging by metabolic click-mediated labelling of rhamnogalacturonan II using azido 3-deoxy- d - manno -oct-2-ulosonic acid
- Author
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Aurélie Baron, Bruno Linclau, Jean-Claude Mollet, Patrice Lerouge, Alan Marchant, Damien Schapman, Arnaud Lehner, Julien Malassis, Ludovic Galas, Boris Vauzeilles, Charles T. Anderson, Jordi Mas Pons, Kevin M. Smyth, Marie Dumont, Laboratoire de Glycobiologie et Matrice Extracellulaire Végétale (Glyco-MEV), Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Normandie Université (NU), Institut de Chimie des Substances Naturelles (ICSN), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), University of Southampton, Pennsylvania State University (Penn State), Penn State System, Plate-Forme de Recherche en Imagerie Cellulaire de Haute-Normandie (PRIMACEN), Normandie Université (NU)-Normandie Université (NU)-Institute for Research and Innovation in Biomedicine (IRIB), Normandie Université (NU)-Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université de Rouen Normandie (UNIROUEN), and Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)
- Subjects
0106 biological sciences ,0301 basic medicine ,Azides ,[SDV.BIO]Life Sciences [q-bio]/Biotechnology ,Pulse labelling ,3-Deoxy-D-manno-oct-2-ulosonic acid ,Cell ,Arabidopsis ,Plant Science ,[SDV.BC.BC]Life Sciences [q-bio]/Cellular Biology/Subcellular Processes [q-bio.SC] ,Calcofluor-white ,Biology ,Plant Roots ,01 natural sciences ,Cell wall ,03 medical and health sciences ,chemistry.chemical_compound ,Cell Wall ,Labelling ,[SDV.BBM.GTP]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Genomics [q-bio.GN] ,Tobacco ,[SDV.BC.IC]Life Sciences [q-bio]/Cellular Biology/Cell Behavior [q-bio.CB] ,Genetics ,medicine ,Monosaccharide ,[SDV.BBM.BC]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biochemistry [q-bio.BM] ,Cells, Cultured ,ComputingMilieux_MISCELLANEOUS ,[SDV.BDD.GAM]Life Sciences [q-bio]/Development Biology/Gametogenesis ,chemistry.chemical_classification ,Staining and Labeling ,Sugar Acids ,[SDV.BBM.BM]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Molecular biology ,[SDV.BBM.MN]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Molecular Networks [q-bio.MN] ,Cell Biology ,Nucleotidyltransferases ,[SDV.BV.PEP]Life Sciences [q-bio]/Vegetal Biology/Phytopathology and phytopharmacy ,[SDV.BV.AP]Life Sciences [q-bio]/Vegetal Biology/Plant breeding ,030104 developmental biology ,medicine.anatomical_structure ,[CHIM.POLY]Chemical Sciences/Polymers ,chemistry ,Biochemistry ,Seedlings ,Click chemistry ,Pectins ,010606 plant biology & botany - Abstract
In plants, 3-deoxy-d-manno-oct-2-ulosonic acid (Kdo) is a monosaccharide that is only found in the cell wall pectin, rhamnogalacturonan-II (RG-II). Incubation of 4-day-old light-grown Arabidopsis seedlings or tobacco BY-2 cells with 8-azido 8-deoxy Kdo (Kdo-N3 ) followed by coupling to an alkyne-containing fluorescent probe resulted in the specific in muro labelling of RG-II through a copper-catalysed azide-alkyne cycloaddition reaction. CMP-Kdo synthetase inhibition and competition assays showing that Kdo and D-Ara, a precursor of Kdo, but not L-Ara, inhibit incorporation of Kdo-N3 demonstrated that incorporation of Kdo-N3 occurs in RG-II through the endogenous biosynthetic machinery of the cell. Co-localisation of Kdo-N3 labelling with the cellulose-binding dye calcofluor white demonstrated that RG-II exists throughout the primary cell wall. Additionally, after incubating plants with Kdo-N3 and an alkynated derivative of L-fucose that incorporates into rhamnogalacturonan I, co-localised fluorescence was observed in the cell wall in the elongation zone of the root. Finally, pulse labelling experiments demonstrated that metabolic click-mediated labelling with Kdo-N3 provides an efficient method to study the synthesis and redistribution of RG-II during root growth.
- Published
- 2016
25. Evolution of severe sleep-wake cycle disturbances following traumatic brain injury: a case study in both acute and subacute phases post-injury
- Author
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Marie Dumont, Catherine Duclos, Nadia Gosselin, Danielle Gilbert, Marie-Julie Potvin, David K. Menon, Francis Bernard, Alex Desautels, Université de Montréal. Faculté des arts et des sciences. Département de psychologie, Menon, David [0000-0002-3228-9692], and Apollo - University of Cambridge Repository
- Subjects
medicine.medical_specialty ,Neurology ,Traumatic brain injury ,medicine.medical_treatment ,Population ,Clinical Neurology ,Poison control ,Case Report ,03 medical and health sciences ,0302 clinical medicine ,medicine ,Neurocritical care ,Circadian rhythms ,030212 general & internal medicine ,education ,education.field_of_study ,Rehabilitation ,business.industry ,Neurointensive care ,Actigraphy ,General Medicine ,Sleep disorders ,medicine.disease ,Neuropsychiatry ,Sleep deprivation ,Emergency medicine ,Physical therapy ,Neurology (clinical) ,medicine.symptom ,business ,030217 neurology & neurosurgery - Abstract
Background Sleep-wake disturbances are frequently reported following traumatic brain injury (TBI), but they remain poorly documented in the acute stage of injury. Little is known about their origin and evolution. Case presentation This study presents the case of a patient in the acute phase of a severe TBI. The patient was injured at work when falling 12 m into a mine and was hospitalized in the regular wards of a level I trauma centre. From days 31 to 45 post-injury, once he had reached a level of medical stability and continuous analgosedation had been ceased, his sleep-wake cycle was monitored using actigraphy. Results showed significant sleep-wake disturbances and severe sleep deprivation. Indeed, the patient had an average nighttime sleep efficiency of 32.7 ± 15.4 %, and only an average of 4.8 ± 1.3 h of sleep per 24-h period. After hospital discharge to the rehabilitation centre, where he remained for 5 days, the patient was readmitted to the same neurological unit for paranoid delusions. During his second hospital stay, actigraphy recordings resumed from days 69 to 75 post-injury. A major improvement in his sleep-wake cycle was observed during this second stay, with an average nighttime sleep efficiency of 96.3 ± 0.9 % and an average of 14.1 ± 0.9 h of sleep per 24-h period. Conclusion This study is the first to extensively document sleep-wake disturbances in both the acute and subacute phases of severe TBI. Results show that prolonged sleep deprivation can be observed after TBI, and suggest that the hospital environment only partially contributes to sleep-wake disturbances. Continuous actigraphic monitoring may prove to be a useful clinical tool in the monitoring of patients hospitalized after severe TBI in order to detect severe sleep deprivation requiring intervention. The direct impact of sleep-wake disturbances on physiological and cognitive recovery is not well understood within this population, but is worth investigating and improving. Electronic supplementary material The online version of this article (doi:10.1186/s12883-016-0709-x) contains supplementary material, which is available to authorized users.
- Published
- 2016
26. Effects of partial circadian adjustments on sleep and vigilance quality during simulated night work
- Author
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Jean Paquet, Marie Dumont, and Simon Chapdelaine
- Subjects
medicine.medical_specialty ,medicine.diagnostic_test ,Cognitive Neuroscience ,media_common.quotation_subject ,General Medicine ,Polysomnography ,Audiology ,Melatonin ,Behavioral Neuroscience ,Alertness ,Mood ,Sleep debt ,Anesthesia ,medicine ,Free-running sleep ,Circadian rhythm ,Psychology ,Vigilance (psychology) ,media_common ,medicine.drug - Abstract
In most situations, complete circadian adjustment is not recommended for night workers. With complete adjustment, workers experience circadian misalignment when returning on a day-active schedule, causing repeated circadian phase shifts and internal desynchrony. For this reason, partial circadian realignment was proposed as a good compromise to stabilize internal circadian rhythms in night shift workers. However, the extent of partial circadian adjustment necessary to improve sleep and vigilance quality is still a matter of debate. In this study, the effects of small but statistically significant partial circadian adjustments on sleep and vigilance quality were assessed in a laboratory simulation of night work to determine whether they were also of clinical significance. Partial adjustments obtained by phase delay or by phase advance were quantified not only by the phase shift of dim light salivary melatonin onset, but also by the overlap of the episode of melatonin production with the sleep-wake cycle adopted during simulated night work. The effects on daytime sleep and night-time vigilance quality were modest. However, they suggest that even small adjustments by phase delay may decrease the accumulation of sleep debt, whereas the advance strategy improves subjective alertness and mood during night work. Furthermore, absolute phase shifts, by advance or by delay, were associated with improved subjective alertness and mood during the night shift. These strategies need to be tested in the field, to determine whether they can be adapted to real-life situations and provide effective support to night workers.
- Published
- 2012
27. Melatonin Production and Light Exposure of Rotating Night Workers
- Author
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Raphaëlle Cadieux-Viau, Marie Dumont, Jean Paquet, and Valérie Lanctôt
- Subjects
Adult ,Work ,endocrine system ,medicine.medical_specialty ,Evening ,Light ,Physiology ,Photoperiod ,Melatonin ,Excretion ,Risk Factors ,Neoplasms ,Work Schedule Tolerance ,Physiology (medical) ,Internal medicine ,Animals ,Humans ,Medicine ,Night work ,Light exposure ,photoperiodism ,business.industry ,Circadian Rhythm ,Pineal melatonin ,Endocrinology ,Sleep ,business ,hormones, hormone substitutes, and hormone antagonists ,medicine.drug - Abstract
Decreased melatonin production, due to acute suppression of pineal melatonin secretion by light exposure during night work, has been suggested to underlie higher cancer risks associated with prolonged experience of night work. However, the association between light exposure and melatonin production has never been measured in the field. In this study, 24-h melatonin production and ambulatory light exposure were assessed during both night-shift and day/evening-shift periods in 13 full-time rotating shiftworkers. Melatonin production was estimated with the excretion of urinary 6-sulfatoxymelatonin (aMT6s), and light exposure was measured with an ambulatory photometer. There was no difference in total 24-h aMT6s excretion between the two work periods. The night-shift period was characterized by a desynchrony between melatonin and sleep-wake rhythms, as shown by higher melatonin production during work and lower melatonin production during sleep when working night shifts than when working day/evening shifts. Light exposure during night work showed no correlation with aMT6s excreted during the night of work (p .5), or with the difference in 24-h aMT6s excretion between the two work periods (p .1). However, light exposure during night work was negatively correlated with total 24-h aMT6s excretion over the entire night-shift period (p .01). In conclusion, there was no evidence of direct melatonin suppression during night work in this population. However, higher levels of light exposure during night work may have decreased total melatonin production, possibly by initiating re-entrainment and causing internal desynchrony. This interpretation is consistent with the proposition that circadian disruption, of which decreased melatonin production is only one of the adverse consequences, could be the mediator between night shiftwork and cancer risks.
- Published
- 2012
28. Sleep in the acute phase of severe traumatic brain injury : a snapshot of polysomnography
- Author
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Catherine Wiseman-Hakes, David K. Menon, Danielle Gilbert, Alex Desautels, Julie Carrier, Marie Dumont, Hélène Blais, Catherine Duclos, Nadia Gosselin, Francis Bernard, and Université de Montréal. Faculté des arts et des sciences. Département de psychologie
- Subjects
Adult ,Male ,Sleep Wake Disorders ,030506 rehabilitation ,medicine.medical_specialty ,Adolescent ,Traumatic brain injury ,Polysomnography ,Acute care ,Young Adult ,03 medical and health sciences ,0302 clinical medicine ,Brain Injuries, Traumatic ,Humans ,Medicine ,Glasgow Coma Scale ,Young adult ,Orthopedic injury ,Sleep Stages ,medicine.diagnostic_test ,business.industry ,General Medicine ,Middle Aged ,medicine.disease ,Intensive Care Units ,Cross-Sectional Studies ,nervous system ,Anesthesia ,Acute Disease ,Female ,Sleep onset ,0305 other medical science ,business ,Sleep ,030217 neurology & neurosurgery - Abstract
Background and Objectives. The onset of pervasive sleep-wake disturbances associated with traumatic brain injury (TBI) is poorly understood. This study aimed to ( a) determine the feasibility of using polysomnography in patients in the acute, hospitalized stage of severe TBI and ( b) explore sleep quality and sleep architecture during this stage of recovery, compared to patients with other traumatic injuries. Methods. A cross-sectional case-control design was used. We examined the sleep of 7 patients with severe TBI (17-47 years; 20.3 ± 15.0 days postinjury) and 6 patients with orthopedic and/or spinal cord injuries (OSCI; 19-58 years; 16.9 ± 4.9 days postinjury). One night of ambulatory polysomnography was performed at bedside. Results. Compared to OSCI patients, TBI patients showed a significantly longer duration of nocturnal sleep and earlier nighttime sleep onset. Sleep efficiency was low and comparable in both groups. All sleep stages were observed in both groups with normal proportions according to age. Conclusion. Patients in the acute stage of severe TBI exhibit increased sleep duration and earlier sleep onset, suggesting that the injured brain enhances sleep need and/or decreases the ability to maintain wakefulness. As poor sleep efficiency could compromise brain recovery, further studies should investigate whether strategies known to optimize sleep in healthy individuals are efficacious in acute TBI. While there are several inherent challenges, polysomnography is a useful means of examining sleep in the early stage of recovery in patients with severe TBI.
- Published
- 2015
29. Abnormal hypothalamic response to light in seasonal affective disorder
- Author
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Julie Carrier, Véronique Daneault, Pierre Maquet, Marie-Lou Garon, Jean Leblanc, Gilles Vandewalle, Laurence Richard, Catherine Beaulieu, Didier Maurice Grandjean, Julien Doyon, Sophie Schwartz, Marie Dumont, and Marc Hébert
- Subjects
Light therapy ,Melanopsin ,Adult ,Male ,medicine.medical_specialty ,Adolescent ,medicine.medical_treatment ,Seasonal Affective Disorder/pathology ,Emotions ,Hypothalamus ,Poison control ,Color ,Audiology ,Article ,03 medical and health sciences ,chemistry.chemical_compound ,Young Adult ,0302 clinical medicine ,ddc:150 ,Oxygen/blood ,medicine ,Electroretinography ,Image Processing, Computer-Assisted ,Reaction Time ,Humans ,Scotopic vision ,Psychiatry ,Biological Psychiatry ,030304 developmental biology ,0303 health sciences ,Light sensitivity ,medicine.diagnostic_test ,Seasonal Affective Disorder ,Retinal ,Middle Aged ,Magnetic Resonance Imaging ,ddc:616.8 ,ddc:128.37 ,Oxygen ,chemistry ,Acoustic Stimulation ,Emotions/physiology ,Hypothalamus/blood supply/physiopathology ,Female ,Psychology ,030217 neurology & neurosurgery ,Photopic vision - Abstract
Background Vulnerability to the reduction in natural light associated with fall/winter is generally accepted as the main trigger of seasonal affective disorder (SAD), whereas light therapy is a treatment of choice of the disorder. However, the relationship between exposure to light and mood regulation remains unclear. As compared with green light, blue light was shown to acutely modulate emotion brain processing in healthy individuals. Here, we investigated the impact of light on emotion brain processing in patients with SAD and healthy control subjects and its relationship with retinal light sensitivity. Methods Fourteen symptomatic untreated patients with SAD (34.5 ± 8.2 years; 9 women) and 16 healthy control subjects (32.3 ± 7.7 years; 11 women) performed an auditory emotional task in functional magnetic resonance imaging during the fall/winter season, while being exposed to alternating blue and green monochromatic light. Scotopic and photopic retinal light sensitivities were then evaluated with electroretinography. Results Blue light enhanced responses to auditory emotional stimuli in the posterior hypothalamus in patients with SAD, whereas green light decreased these responses. These effects of blue and green light were not observed in healthy control subjects, despite similar retinal sensitivity in SAD and control subjects. Conclusions These results point to the posterior hypothalamus as the neurobiological substrate involved in specific aspects of SAD, including a distinctive response to light and altered emotional responses.
- Published
- 2011
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30. Effects of melatonin and bright light administration on motor and sensory symptoms of RLS
- Author
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Alex Desautels, Jacques Montplaisir, Dominique Petit, Benoit Adam, Shirley Whittom, Gilles Lavigne, and Marie Dumont
- Subjects
Adult ,Male ,medicine.medical_specialty ,Time Factors ,Sensation ,Poison control ,Exogenous melatonin ,Sensory system ,Melatonin ,Immobilization ,Restless Legs Syndrome ,Internal medicine ,mental disorders ,medicine ,Humans ,Sensory symptoms ,Motor Manifestations ,Restless legs syndrome ,Saliva ,business.industry ,General Medicine ,Middle Aged ,Phototherapy ,medicine.disease ,Endocrinology ,Physical therapy ,Female ,business ,Psychomotor Performance ,Bright light ,medicine.drug - Abstract
Background A close temporal relationship was shown between the onset of melatonin secretion at night and the worsening of restless legs syndrome (RLS) symptoms, suggesting that melatonin may play a role in the genesis of this phenomenon. To test this hypothesis we studied the effects of the administration of exogenous melatonin and, conversely, the suppression of endogenous melatonin secretion by bright light exposure on the severity of RLS symptoms. Methods Eight RLS subjects were studied in three conditions: at baseline, after administration of melatonin and during bright light exposure. The severity of RLS symptoms was assessed by the suggested immobilization test (SIT), which allows quantification of both sensory and motor manifestations (SIT-PLM) of RLS. Results Analyses showed a significant increase of SIT-PLM index when subjects received exogenous melatonin compared to both baseline and bright light conditions, but bright light exposure had no effect on leg movements compared to the baseline condition. Analyses also revealed a small but significant decrease in sensory symptoms with bright light exposure compared to baseline. Conclusion Exogenous melatonin may have a detrimental effect on motor symptoms, and bright light exposure produced small but significant improvement of leg discomfort. The study shows the interest of using the SIT to measure outcome of intervention in RLS. Further studies will be needed to assess the therapeutic value of bright light in RLS.
- Published
- 2010
31. Nighttime Blood Pressure in Normotensive Subjects With Chronic Insomnia: Implications for Cardiovascular Risk
- Author
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Lorraine Fradette, Marie-Hélène Pennestri, Paola Lanfranchi, Marie Dumont, Jacques Montplaisir, and Charles M. Morin
- Subjects
Adult ,Male ,medicine.medical_specialty ,Polysomnography ,Primary Insomnia ,Population ,Blood Pressure ,Audiology ,Non-rapid eye movement sleep ,Arousal ,Risk Factors ,Sleep Initiation and Maintenance Disorders ,Physiology (medical) ,medicine ,Insomnia ,Humans ,Prospective Studies ,Psychiatry ,education ,Sleep disorder ,education.field_of_study ,medicine.diagnostic_test ,Signal Processing, Computer-Assisted ,Middle Aged ,Nocturnal Blood Pressure in Chronic Insomnia ,medicine.disease ,Circadian Rhythm ,Survival Rate ,Cardiovascular Diseases ,Case-Control Studies ,Female ,Sleep diary ,Neurology (clinical) ,medicine.symptom ,Beta Rhythm ,Psychology - Abstract
INSOMNIA REFERS TO THE SUBJECTIVE EXPERIENCE OF NON RESTORATIVE SLEEP DUE TO DIFFICULTY FALLING ASLEEP, DIFFICULTY MAINTAINING SLEEP or early awakening.1,2 Insomnia is the most common sleep complaint in the general population, with a variable prevalence ranging from 2% to 48%, a broad range which reflects the variable definition of insomnia, different modalities of investigation, and the population under study.2,3 Indeed, insomnia may appear in association with another medical or psychiatric disorder (comorbid insomnia), or as an independent condition as primary insomnia.3 Hallmarks of primary insomnia are the subjective experience of difficulty initiating and maintaining sleep, accompanied by distress or impairment in daytime function; the repetitive (as opposed to sporadic) recurrence of a poor sleep night;4 and duration of ≥ 1 month (according to DSM-IV definition)5, whereas ≥ 6 months duration is required to fulfill diagnostic criteria for chronic insomnia.1–3 The pathophysiological mechanisms of primary insomnia remain elusive. Psychophysiological factors such as stress, anxiety, and autonomic hyperarousal are significant components of this condition6 and would appear to be implicated in its genesis and perpetuation. Polysomnography often fails to detect traditional criteria of poor sleep in insomniacs.2 However, studies assessing quantitative electroencephalographic (EEG) spectral analysis have shown that, even in the presence of an apparently normal sleep architecture during polysomnography, these subjects have a decrease in EEG activity in the low frequencies (0.5-3.5 Hz) and an increased activity in high frequencies (14-45 Hz) during NREM sleep,7–9 suggesting hyperactivity of the central nervous system during their sleep. Finally, studies using positron emission tomography assessing metabolic activity during NREM sleep have documented that insomniacs, compared to good sleepers, have higher metabolic activity in the ascending reticular activating system, along with areas pertaining to the emotion regulation and cognitive systems.10 These data suggest that the interaction of the systems regulating arousal, emotions, and cognitive function is part of the neurobiology of insomnia and support the concept that poor sleep is a symptom of a primary disorder of the arousal system. Indeed, as part of the arousal response, nocturnal plasma catecholamine concentration11 and low frequency components of heart rate variability have been reported to be higher in insomniacs than good sleepers.12 Insomnia significantly impairs daytime function and predisposes to major depression.1,3 There is also an emerging epidemiological evidence linking insomnia to higher cardiovascular morbidity and mortality.13–17 However, at present, no studies have assessed the effects of insomnia on cardiovascular function, and to our knowledge, no data exist on nighttime BP, which has been shown to be relevant in assessing cardiovascular risk in recent large studies.18,19 Blood pressure physiologically decreases during sleep,20 a reduction commonly called dipping. Studies indicated that day-to-night and nighttime regulation of BP appear to be tightly coupled with autonomic changes occurring during the wake-sleep cycle.21,22 This suggests that BP should be particularly sensitive to disturbances occurring during sleep, especially in the presence of hyperactivation of the sympathetic nervous system, such as that which may occur in insomniacs. In the present study we investigated the 24-hour profile of arterial BP in subjects with chronic primary insomnia and tested the hypothesis that these subjects have higher nighttime BP and an attenuation of nocturnal BP dipping compared to good sleepers. We also assessed the relationship existing between nighttime BP and polysomnographic measures of poor sleep and EEG power spectra in the β frequencies.
- Published
- 2009
32. Light exposure in the natural environment: Relevance to mood and sleep disorders
- Author
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Catherine Beaulieu and Marie Dumont
- Subjects
Light ,Mood Disorders ,media_common.quotation_subject ,Circadian clock ,General Medicine ,medicine.disease ,Circadian Rhythm ,Developmental psychology ,Affect ,Mood ,Mood disorders ,Dark therapy ,Biological Clocks ,Sleep Disorders, Circadian Rhythm ,Work Schedule Tolerance ,medicine ,Humans ,Free-running sleep ,Wakefulness ,Circadian rhythm ,Psychology ,Neuroscience ,Vigilance (psychology) ,media_common - Abstract
In addition to being necessary for vision, light also plays a primary role in circadian physiology. Humans are diurnal animals and their biological clock synchronizes their physiological functions in such a way that functions associated with activity happen in the daytime while functions associated with rest occur at night. A misalignment between the endogenous circadian clock and the desired sleep schedule is the main cause of circadian sleep disorders; it may be involved in certain mood disorders as well. Since light is the main environmental cue used by the biological clock to set its own timing in relation to the day-night cycle, inappropriate light exposure can be involved in the physiopathology of circadian disorders. Conversely, when handled properly, controlled light exposure can be used to treat some mood and sleep disorders. While the earliest studies in the field focused solely on exposure to bright light, contemporary studies aim at understanding how the entire profile of light-dark exposure can influence the circadian clock and, consequently, mood, sleep, and vigilance quality. Following a brief summary of the main concepts underlying the non-visual effects of light, this paper presents some studies using ambulatory measurements of light exposure to illustrate how these concepts apply in real-life situations and discusses the clinical relevance of light exposure in the natural environment for mood, sleep, and circadian disorders.
- Published
- 2007
33. Difference in sleep regulation between morning and evening circadian types as indexed by antero-posterior analyses of the sleep EEG
- Author
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Valérie Mongrain, Marie Dumont, and Julie Carrier
- Subjects
medicine.medical_specialty ,Evening ,medicine.diagnostic_test ,General Neuroscience ,Eye movement ,Polysomnography ,Audiology ,Non-rapid eye movement sleep ,Sleep in non-human animals ,Endocrinology ,Internal medicine ,medicine ,Circadian rhythm ,Psychology ,Slow-wave sleep ,Morning - Abstract
Circadian types classify individuals according to their preferred timing for activity and sleep, morning and evening types showing, respectively, early or late preferences. This characteristic has been associated with corresponding differences in circadian sleep propensity. In this study, quantitative analysis of the sleep EEG in antero-posterior derivations was used to test the hypothesis that morning and evening types differ not only in the circadian aspect of sleep regulation but also in the homeostatic aspect. Morning types and evening types (six men and six women per group, aged 19-34 years) were selected using the Morningness-Eveningness Questionnaire. They were studied by polysomnography according to their preferred sleep schedule. Spectral activity in four midline derivations (Fz, Cz, Pz, Oz) was calculated separately in nonrapid eye movement (NREM) sleep and in rapid eye movement (REM) sleep. In NREM sleep, morning types showed a steeper decrease of slow-wave activity (SWA; 1-5 Hz) per sleep cycle in the fronto-central derivations and a steeper increase in 13-14 Hz activity in the parieto-occipital derivations than did evening types. Nonlinear regression analysis revealed that the exponential decay rate of relative values of SWA in NREM sleep was faster in morning than evening types, in the frontal derivation. In REM sleep, morning types showed a steeper decrease of high sigma (14-16 Hz) and beta (16-24 Hz) activities across the night in centro-parietal derivations than did evening types. These results show for the first time a clear difference between morning types and evening types in homeostatic sleep regulation.
- Published
- 2006
34. Are Modifications of Melatonin Circadian Rhythm in the Middle Years of Life Related to Habitual Patterns of Light Exposure?
- Author
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Jean Paquet, Brahim Selmaoui, Anna Kawinska, Marie Dumont, and Julie Carrier
- Subjects
Adult ,Male ,0301 basic medicine ,medicine.medical_specialty ,Time Factors ,Light ,Physiology ,Biological clock ,Statistics as Topic ,Radioimmunoassay ,Biology ,Melatonin ,03 medical and health sciences ,0302 clinical medicine ,Biological Clocks ,Surveys and Questionnaires ,Physiology (medical) ,Internal medicine ,medicine ,Humans ,Circadian rhythm ,Saliva ,Morning ,Light exposure ,Phase advance ,Wake time ,Middle Aged ,Middle age ,Circadian Rhythm ,030104 developmental biology ,Endocrinology ,Female ,030217 neurology & neurosurgery ,medicine.drug - Abstract
The mechanisms underlying age-related changes in the signal from the biological clock have yet to be determined. The authors sought to determine if the phase advance of circadian melatonin rhythm during the middle years of life is related to different patterns of habitual light exposure. Forty-one healthy subjects between the ages of 22 and 58 y were studied. Habitual light exposure was measured by a wrist monitor for 7 days. Participants underwent a 25-h constant routine. They provided saliva samples every 30 min, and melatonin concentration was determined by radioimmunoassay to assess salivary dim light melatonin onset (S-DLMO1.3). Aging was associated with earlier S-DLMO1.3. Increasing age was not related to the time spent at different light intensities. However, it was associated with lower percentage of light exposure during the night (between 0200-0400, 0600-0700, and 2300-2400 h) and with higher percentage of light exposure in the morning (between 0800-1100 h). Earlier S-DLMO1.3 was associated with lower percentage of light exposure early on in the night (between 2200-0000, 0000-0100, and 0200-0300 h) as well as in the afternoon (between 1500-1600 h) and with higher percentage of light exposure in the morning (between 0800-1100 h). When the effects of age were controlled, there was no significant relationship between S-DLMO1.3 and percentages of light exposure. Yet increasing age was associated with earlier S-DLMO1.3 regardless of light exposure patterns. Earlier habitual wake time explained the earlier light exposure patterns of older subjects. Both habitual wake time and age contributed to the prediction of S-DLMO1.3. The results suggest a phase advance of circadian rhythms in the middle years of life. Whereas a clear change in habitual light exposure patterns was associated with aging and with shifts in S-DLMO1.3, it did not explain entirely the age-related advance of melatonin circadian phase.
- Published
- 2005
35. Psychodynamic assessment of changes in children with autism under psychoanalytic treatment
- Author
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Geneviève Haag, Franoise Jardin, Annick Cukierman, Simone Urwand, Jacqueline Tricaud, Sylvie Tordjman, Anik Maufras du Chatellier, Catherine Druon, Marie‐Christine Cl, Anne‐Marie Dumont, and Andre Duprat
- Subjects
Psychotherapist ,Psychoanalysis ,Adolescent ,Personality development ,Anxiety ,050108 psychoanalysis ,Personality Assessment ,Individuation ,Id, ego and super-ego ,Body Image ,medicine ,Cognitive development ,Humans ,0501 psychology and cognitive sciences ,Autistic Disorder ,Psychoanalytic theory ,Child ,Social Behavior ,Internal-External Control ,Defense Mechanisms ,Ego ,Loevinger's stages of ego development ,05 social sciences ,Infant ,Awareness ,medicine.disease ,Psychodynamics ,Object Attachment ,Psychoanalytic Therapy ,Psychiatry and Mental health ,Clinical Psychology ,Personality Development ,Child, Preschool ,Psychoanalytic Theory ,Autism ,Psychology ,050104 developmental & child psychology - Abstract
In this article the authors report insights into autism developed through their extensive experience of psychoanalytic therapy with children with autism. The first stages of body psychic development are seriously disrupted by this pathology, resulting in primitive anxieties of falling and of being liquefied. These anxieties are connected to the fragile development of body ego and of its related spatiotemporal organisation. The changes in children observed by the authors during the therapeutic process lead them to offer a psychodynamic assessment tool, which revolves principally around the development of body ego. After the initial state of 'severe autism', the authors describe three stages: the stage of 'recovery of the skin' (Bick); the established 'symbiotic phase', subdivided into 'vertical then horizontal splitting of the body ego'; and finally the stage of 'individuation'. First, the authors describe the principal psychoanalytic approaches to autism and reflect on the links possible with non-psychoanalytic work.
- Published
- 2005
36. Phase Relationships between Sleep-Wake Cycle and Underlying Circadian Rhythms in Morningness-Eveningness
- Author
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Marie Dumont, Suzie Lavoie, Valérie Mongrain, Brahim Selmaoui, and Jean Paquet
- Subjects
Adult ,Male ,0301 basic medicine ,medicine.medical_specialty ,Time Factors ,Evening ,Physiology ,Photoperiod ,Audiology ,Body Temperature ,Correlation ,Melatonin ,03 medical and health sciences ,0302 clinical medicine ,Biological Clocks ,Physiology (medical) ,Internal medicine ,medicine ,Humans ,Circadian rhythm ,photoperiodism ,business.industry ,Phase angle ,Actigraphy ,Circadian Rhythm ,030104 developmental biology ,Endocrinology ,Female ,Sleep ,Entrainment (chronobiology) ,business ,030217 neurology & neurosurgery ,medicine.drug - Abstract
A shorter phase angle between habitual wake time and underlying circadian rhythms has been reported in evening types (E types) compared to morning-types (M types). In this study, phase angles were compared between 12 E types and 12 M types to verify if this difference was observed when the sleep schedule was relatively free from external social constraints. Subjects were selected according to their Morningness-Eveningness Questionnaire score (MEQ score). There were 6 men and 6 women in each group (ages 19-34 years), and all had a habitual sleep duration between 7 and 9 h. Sleep schedule was recorded by actigraphy and averaged over 7 days. Circadian phase was estimated by the hour of temperature minimum (Tmin) in a 26-h recording and by the timing of the onset of melatonin secretion (dim-light melatonin onset [DLMO]) measured in saliva samples. Phase angles were defined as the interval between phase markers and averaged wake time. Results showed that, in the present experimental conditions, phase angles were very similar in the 2 groups of subjects. However, results confirmed the previously reported correlation between phase and phase angle, showing that a later circadian phase was associated with a shorter phase angle. Gender comparisons showed that for a same MEQ score, women had an earlier DLMO and a longer phase angle between DLMO and wake time. Despite a significant difference in the averaged circadian phases between E-type and M-type groups, there was an overlap in the circadian phases of the subjects of the 2 groups. Further comparisons were made between the 2 circadian types, separately for the subgroups with overlapping or nonoverlapping circadian phases. In both subgroups, the significant difference between MEQ scores, bedtimes, and wake times were maintained in the expected direction. In the subgroup with nonoverlapping circadian phases, phase angles were shorter in E-type subjects, in accordance with previous studies. However, in the overlapping subgroup, phase angles were significantly longer in E types compared to M types. Results suggest that the morningness-eveningness preference identified by the MEQ score refers to 2 distinct mechanisms, 1 associated with a difference in circadian period and phase of entrainment and the other associated with chronobiological aspects of sleep regulation.
- Published
- 2004
37. Circadian rhythm of restless legs syndrome: Relationship with biological markers
- Author
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Brahim Selmaoui, Martin Michaud, Jacques Montplaisir, Marie Dumont, Jean Paquet, and Maria Livia Fantini
- Subjects
Adult ,Male ,medicine.medical_specialty ,Time Factors ,Evening ,Polysomnography ,media_common.quotation_subject ,Neurological disorder ,Neuropsychological Tests ,Body Temperature ,Melatonin ,Immobilization ,Dopamine secretion ,Restless Legs Syndrome ,Internal medicine ,mental disorders ,medicine ,Humans ,Circadian rhythm ,Restless legs syndrome ,Saliva ,Demography ,media_common ,Chi-Square Distribution ,Electromyography ,Middle Aged ,medicine.disease ,Circadian Rhythm ,Endocrinology ,Neurology ,Female ,Neurology (clinical) ,Arousal ,Psychology ,Chi-squared distribution ,Biomarkers ,Vigilance (psychology) ,medicine.drug - Abstract
Recently, it was suggested that the intensity of restless legs syndrome (RLS) symptoms may be modulated by a circadian factor. The objective of this study was to evaluate, during a 28-hour modified constant routine, the nycthemeral or circadian variations in subjective leg discomfort and periodic leg movements (PLMs) and to parallel these changes with those of subjective vigilance, core body temperature, and salivary melatonin. Seven patients with primary RLS and seven healthy subjects matched for sex and age entered this study. Although the symptoms were more severe in patients than in controls, a significant circadian variation in leg discomfort and PLM (p < 0.01) was found for both groups. In both groups, the profiles of leg discomfort and PLM were significantly correlated with those of subjective vigilance, core body temperature, and salivary melatonin. However, among these variables, the changes in melatonin secretion were the only ones that preceded the increase in sensory and motor symptoms in RLS patients. This result and those of others studies showing that melatonin exerts an inhibitory effect on central dopamine secretion suggest that melatonin might be implicated in the worsening of RLS symptoms in the evening and during the night.
- Published
- 2004
38. What is the quality of clinical practice guidelines accessible on the world wide web for the treatment of musculoskeletal conditions in physiotherapy?
- Author
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Lynn Casimiro, Lucie Brosseau, Mélanie Gravel, Ian D. Graham, Shaun Cleaver, Allison March, Jessie McGowan, Lynn MacLeay, and Anne-Marie Dumont
- Subjects
medicine.medical_specialty ,business.industry ,media_common.quotation_subject ,Alternative medicine ,Physical Therapy, Sports Therapy and Rehabilitation ,Confidence interval ,Clinical Practice ,Quality Score ,Health care ,Physical therapy ,Medicine ,Quality (business) ,business ,Methodological quality ,human activities ,Inclusion (education) ,media_common - Abstract
Health care professionals have a duty to provide the best services available to their clients. Clinical practice guidelines (CPGs) can help physiotherapists do so by providing them with access to clinical recommendations for evaluating and treating various conditions. The purpose of this study was twofold: to assess the quality of existing CPGs in physiotherapy and to create a Web-based inventory of these CPGs. Nine guidelines were selected (consisting of 61 recommendation statements) according to predetermined inclusion/exclusion criteria and then independently quality assessed by four appraisers using the AGREE (Appraisal of Guidelines for Research and Evaluation) Instrument. The methodological quality of these musculoskeletal CPGs was fair (mean quality score of 46.6%; range 0%–83%; [95% confidence interval {CI} 17.0%–70.5%]) depending on the specific AGREE dimension.
- Published
- 2004
39. The photopic ERG luminance-response function (photopic hill): method of analysis and clinical application
- Author
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Olga Dembinska, John M. Little, Pierre Lachapelle, Robert K. Koenekoop, Marie Dumont, Robert C. Polomeno, Marianne Rufiange, Justine Dassa, and Sylvain Chemtob
- Subjects
Adult ,Male ,Adolescent ,Light ,Visual sensitivity ,Plateau (mathematics) ,Luminance ,Retina ,b-wave ,Optics ,Photopic ,Electroretinography ,medicine ,Humans ,Luminance-response function ,Scotopic vision ,medicine.diagnostic_test ,Adaptation, Ocular ,business.industry ,Sensory Systems ,Ophthalmology ,Amplitude ,ERG ,Visual Perception ,Curve fitting ,Female ,business ,Psychology ,Erg ,Photic Stimulation ,Photopic vision - Abstract
With progressively brighter stimuli, the amplitude of the photopic b-wave first increases, briefly saturates and then decreases gradually to reach a plateau, where the amplitude of the b-wave equals that of the a-wave; a phenomenon previously presented as the photopic hill. The unique presentation of this luminance-response function seriously complicates its analysis with curve fitting equations such as that of Naka–Rushton used for scotopic electroretinogram. We report a method of analysis of the photopic hill based on easily identifiable and reproducible features of the ascending and descending limbs of this function. The clinical usefulness of these parameters is illustrated with selected cases of retinal disorders.
- Published
- 2003
40. Vigilance Levels During and After Bright Light Exposure in the First Half of the Night
- Author
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Marie Dumont, Brahim Selmaoui, Marianne Rufiange, Jean Paquet, and Suzie Lavoie
- Subjects
Adult ,Male ,Cortisol secretion ,medicine.medical_specialty ,Hydrocortisone ,Light ,Physiology ,media_common.quotation_subject ,Body Temperature ,Melatonin ,Surveys and Questionnaires ,Physiology (medical) ,Internal medicine ,medicine ,Humans ,Attention ,Circadian rhythm ,Wakefulness ,media_common ,Electroencephalography ,Alertness ,Sleep deprivation ,Endocrinology ,Sleep Deprivation ,Female ,medicine.symptom ,Psychology ,Psychomotor Performance ,medicine.drug ,Vigilance (psychology) - Abstract
Fourteen healthy subjects (8 women, 6 men, aged 22-35 yr) were recruited. Each subject was exposed, in a counterbalanced order, to bright white light (BWL: 3000 lux) and to dim red light (DRL
- Published
- 2003
41. Electrophysiological evidence suggesting a seasonal modulation of retinal sensitivity in subsyndromal winter depression
- Author
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Marc Hébert, Marie Dumont, and Pierre Lachapelle
- Subjects
Adult ,Male ,medicine.medical_specialty ,Audiology ,Retina ,Developmental psychology ,chemistry.chemical_compound ,Reference Values ,Retinal Rod Photoreceptor Cells ,Electroretinography ,medicine ,Humans ,Scotopic vision ,Young adult ,medicine.diagnostic_test ,Adaptation, Ocular ,Seasonal Affective Disorder ,Retinal ,Retinal adaptation ,Psychiatry and Mental health ,Clinical Psychology ,medicine.anatomical_structure ,Mood ,chemistry ,Sensory Thresholds ,Female ,sense organs ,Psychology ,Erg - Abstract
Background: An anomaly in the retinal adaptation processes to the decreased light exposure in winter has been suggested as a contributing factor in winter depression. The purpose of this study was to investigate seasonal variations in rod sensitivity in normal subjects and in subjects with seasonal mood variations. Methods: Nine normal subjects (5 men, 4 women, aged 21–28 years) and 12 subjects with subsyndromal seasonal affective disorder (S-SAD)(3 men, 9 women, aged 21–44 years) were selected based on their global seasonality score (GSS) from the Seasonal Pattern Assessment Questionnaire. Scotopic electroretinograms (ERGs) were obtained once in winter and once in summer. Retinal sensitivity, which represents a relative threshold, was obtained from the rod ERG luminance–response functions. Results: A difference in retinal sensitivity between the two groups appeared only in the winter with lower retinal sensitivity found in the S-SAD group. A positive correlation between the GSS and the magnitude of the winter decrease in rod sensitivity was also observed. Limitations: The S-SAD subjects studied in this research did not receive a formal psychiatric evaluation. This will be necessary in future studies to determine if the changes in retinal sensitivity are specific to seasonal affective disorders. In addition, in the present study, the differences in age and gender between the two groups limit the interpretation of the possible contribution of these two parameters to the results. Conclusion: The seasonal changes in retinal sensitivity that parallel seasonal mood variations suggest that the ERG may represent a useful tool to investigate seasonal affective disorders.
- Published
- 2002
42. 1144 PRESENCE OF MELATONIN RHYTHM IN ACUTE MODERATE-SEVERE TRAUMATIC BRAIN INJURY DESPITE SEVERE SLEEP-WAKE DISTURBANCES
- Author
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Nadia Gosselin, Francis Bernard, Catherine Duclos, Marie Dumont, David K. Menon, Hélène Blais, Jean Paquet, and M Quinn
- Subjects
Traumatic brain injury ,business.industry ,Physiology (medical) ,Sleep wake ,Anesthesia ,Melatonin rhythm ,medicine ,Neurology (clinical) ,Medical emergency ,medicine.disease ,business - Published
- 2017
43. 1175 SLEEP-WAKE CYCLE AND EARLY NEUROLOGICAL RECOVERY AFTER MODERATE TO SEVERE TRAUMATIC BRAIN INJURY
- Author
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Héjar El-Khatib, Nathalie Gosselin, S. Van der Maren, L Pizzimenti, David K. Menon, Francis Bernard, Hélène Blais, Caroline Arbour, Marie Dumont, M Potvin, and Catherine Duclos
- Subjects
Moderate to severe ,business.industry ,Traumatic brain injury ,Physiology (medical) ,Anesthesia ,Medicine ,Neurology (clinical) ,Circadian rhythm ,business ,medicine.disease - Published
- 2017
44. Progressive decrease of melatonin production over consecutive days of simulated night work
- Author
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Marie Dumont and Jean Paquet
- Subjects
6-sulfatoxymelatonin ,Adult ,Male ,medicine.medical_specialty ,Circadian phase ,Light ,Physiology ,Light at night ,Melatonin ,Young Adult ,Risk Factors ,Physiology (medical) ,Internal medicine ,Neoplasms ,Work Schedule Tolerance ,medicine ,Humans ,Night work ,Occupational Health ,business.industry ,Healthy subjects ,Circadian Rhythm ,Endocrinology ,Female ,Cancer risk ,business ,hormones, hormone substitutes, and hormone antagonists ,Night Shift Work ,medicine.drug ,Contraceptives, Oral - Abstract
Decreased melatonin production, due to nighttime exposure to light, has been proposed as one of the physiological mechanisms increasing cancer risk in night workers. However, few studies measured melatonin production in night workers, and most of these studies did not measure melatonin over 24 h. One study compared total melatonin production between day and night shifts in rotating night workers and did not find significant differences. However, without baseline measures, it was not possible to exclude that melatonin production was reduced during both day and night work. Here, we used data collected in a simulation study of night work to determine the effect of night work on both nighttime and 24-h melatonin production, during three consecutive days of simulated night work. Thirty-eight healthy subjects (15 men, 23 women; 26.6 ± 4.2 years) participated in a 6-d laboratory study. Circadian phase assessments were made with salivary dim light melatonin onset (DLMO) on the first and last days. Simulated day work (09:00-17:00 h) occurred on the second day, followed by three consecutive days of simulated night work (00:00-08:00 h). Light intensity at eye level was set at 50 lux during both simulated day and night work. The subjects were divided into three matched groups exposed to specific daytime light profiles that produced various degrees of circadian phase delays and phase advances. Melatonin production was estimated with the excretion of urinary 6-sulfatoxymelatonin (aMT6s). For the entire protocol, urine was collected every 2 h, except for the sleep episodes when the interval was 8 h. The aMT6s concentration in each sample was multiplied by the urine volume and then added to obtain total aMT6s excretion during nighttime (00:00-08:00 h) and during each 24-h day (00:00-00:00 h). The results showed that melatonin production progressively decreased over consecutive days of simulated night work, both during nighttime and over the 24 h. This decrease was larger in women using oral contraceptives. There was no difference between the three groups, and the magnitude of the decrease in melatonin production for nighttime and for the 24 h was not associated with the magnitude of the absolute circadian phase shift. As light intensity was relatively low and because the decrease in melatonin production was progressive, direct suppression by nighttime light exposure was probably not a significant factor. However, according to previous experimental observations, the decrease in melatonin production most likely reflects the circadian disruption associated with the process of re-entrainment. It remains to be determined whether reduced melatonin production can be harmful by itself, but long-term and repeated circadian disruption most probably is.
- Published
- 2014
45. Aging reduces the stimulating effect of blue light on cognitive brain functions
- Author
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Julien Doyon, Geneviève Albouy, Véronique Daneault, Gilles Vandewalle, Julie Carrier, Marie Dumont, Marc Hébert, and Université de Montréal. Faculté des arts et des sciences. Département de psychologie
- Subjects
Adult ,Male ,Aging ,Light ,Color ,Neuroimaging ,Aging Reduces the Stimulating Effect of Blue Light on Cognitive Brain Functions ,Melanopsin ,Amygdala ,Cataract ,Arousal ,Cognition ,Functional neuroimaging ,Physiology (medical) ,Surveys and Questionnaires ,medicine ,Humans ,Attention ,Cerebral Cortex ,medicine.diagnostic_test ,Working memory ,fMRI ,Circadian ,Quebec ,Rod Opsins ,Brain ,Pupil ,Darkness ,Middle Aged ,Magnetic Resonance Imaging ,Healthy Volunteers ,Circadian Rhythm ,Alertness ,medicine.anatomical_structure ,Nonvisual ,Cross-Sectional Studies ,Memory, Short-Term ,Female ,Neurology (clinical) ,Psychology ,Functional magnetic resonance imaging ,Neuroscience ,Blue light - Abstract
Study Objectives: Light exposure, particularly blue light, is being recognized as a potent mean to stimulate alertness and cognition in young individuals. Aging is associated with changes in alertness regulation and cognition. Whether the effect of light on cognitive brain function changes with aging is unknown, however. Design: Cross-sectional study. Setting: Functional Neuroimaging Unit, University of Montreal Geriatric Institute. Participants: Sixteen younger (23 ± 4.1 y) and 14 older (61 ± 4.5 y) healthy participants were recruited in the current study. Intervention: Blue light administration. Measurements: We used functional magnetic resonance imaging to record brain responses to an auditory working memory task in young and older healthy individuals, alternatively maintained in darkness or exposed to blue light. Results: Results show that the older brain remains capable of showing sustained responses to light in several brain areas. However, compared to young individuals, the effect of blue light is decreased in the pulvinar, amygdala, and tegmentum as well as in the insular, prefrontal, and occipital cortices in elderly individuals. Conclusion: The effect of blue light on brain responses diminishes with aging in areas typically involved in visual functions and in key regions for alertness regulation and higher executive processes. Our findings provide the first indications that the effect of light on cognition may be reduced in healthy aging.
- Published
- 2014
46. The cell wall pectic polymer rhamnogalacturonan-II is required for proper pollen tube elongation: implications of a putative sialyltransferase-like protein
- Author
-
Arnaud Lehner, Marie Christine Kiefer-Meyer, Marie Dumont, Jean-Claude Mollet, Sophie Bouton, Patrice Lerouge, Aline Voxeur, Jérôme Pelloux, Laboratoire de Glycobiologie et Matrice Extracellulaire Végétale (Glyco-MEV), Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Normandie Université (NU), Biologie des Plantes et Innovation - UR UPJV 3900 (BIOPI), Université de Picardie Jules Verne (UPJV)-Transfrontalière BioEcoAgro - UMR 1158 (BioEcoAgro), Université d'Artois (UA)-Université de Liège-Université de Picardie Jules Verne (UPJV)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-JUNIA (JUNIA), Université catholique de Lille (UCL)-Université catholique de Lille (UCL)-Université d'Artois (UA)-Université de Liège-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-JUNIA (JUNIA), Université catholique de Lille (UCL)-Université catholique de Lille (UCL), Institut Jean-Pierre Bourgin (IJPB), Institut National de la Recherche Agronomique (INRA)-AgroParisTech, University of Rouen, 'Trans Channel Wallnet' project, ERDF, Biologie des Plantes et Innovation (BIOPI), Université de Picardie Jules Verne (UPJV), Laboratoire de Glycobiologie et Matrice Extracellulaire Végétale ( Glyco-MEV ), Université de Rouen Normandie ( UNIROUEN ), Normandie Université ( NU ) -Normandie Université ( NU ), Institut Jean-Pierre Bourgin ( IJPB ), Institut National de la Recherche Agronomique ( INRA ) -AgroParisTech, 0977 Unité associée de Biologie forestière, and Institut National de la Recherche Agronomique ( INRA )
- Subjects
[SDV.BIO]Life Sciences [q-bio]/Biotechnology ,Arabidopsis thaliana ,Polymers ,[SDV]Life Sciences [q-bio] ,Mutant ,Arabidopsis ,MESH : Pollen Tube ,Kdo ,Plant Science ,[SDV.BC.BC]Life Sciences [q-bio]/Cellular Biology/Subcellular Processes [q-bio.SC] ,medicine.disease_cause ,MESH : Arabidopsis Proteins ,MESH : Arabidopsis ,[ SDV.BBM.BC ] Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biomolecules [q-bio.BM] ,Cell Wall ,Gene Expression Regulation, Plant ,Genes, Reporter ,MESH : Pectins ,[SDV.BC.IC]Life Sciences [q-bio]/Cellular Biology/Cell Behavior [q-bio.CB] ,plant cell wall ,[SDV.BDD]Life Sciences [q-bio]/Development Biology ,RG-II ,food and beverages ,MESH : Sialyltransferases ,[ SDV.BV.PEP ] Life Sciences [q-bio]/Vegetal Biology/Phytopathology and phytopharmacy ,Articles ,MESH : Genes, Reporter ,Dha ,MESH : Phenotype ,[ SDV.BV.AP ] Life Sciences [q-bio]/Vegetal Biology/Plant breeding ,Phenotype ,Biochemistry ,Germination ,Organ Specificity ,[ SDV.BBM.GTP ] Life Sciences [q-bio]/Biochemistry, Molecular Biology/Genomics [q-bio.GN] ,Pectins ,Pollen ,Pollen tube ,MESH : Mutation ,[SDV.BC]Life Sciences [q-bio]/Cellular Biology ,[ SDV.BBM.BM ] Life Sciences [q-bio]/Biochemistry, Molecular Biology/Molecular biology ,Biology ,[ SDV.BC.IC ] Life Sciences [q-bio]/Cellular Biology/Cell Behavior [q-bio.CB] ,Cell wall ,MESH : Organ Specificity ,[ SDV.BBM.MN ] Life Sciences [q-bio]/Biochemistry, Molecular Biology/Molecular Networks [q-bio.MN] ,[ SDV.BDD.GAM ] Life Sciences [q-bio]/Development Biology/Gametogenesis ,[SDV.BBM.GTP]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Genomics [q-bio.GN] ,medicine ,[SDV.BV]Life Sciences [q-bio]/Vegetal Biology ,MESH : Pollen ,[SDV.BBM.BC]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biochemistry [q-bio.BM] ,MESH : Polymers ,MESH : Cell Wall ,Reporter gene ,Arabidopsis Proteins ,MESH : Sugar Acids ,pectin motif ,Wild type ,[ SDV.BC.BC ] Life Sciences [q-bio]/Cellular Biology/Subcellular Processes [q-bio.SC] ,sialyltransferase-like protein ,Sugar Acids ,[ SDV.BIO ] Life Sciences [q-bio]/Biotechnology ,[SDV.BBM.BM]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Molecular biology ,biology.organism_classification ,Molecular biology ,pollen tube ,Sialyltransferases ,[SDV.BV.PEP]Life Sciences [q-bio]/Vegetal Biology/Phytopathology and phytopharmacy ,[ CHIM.POLY ] Chemical Sciences/Polymers ,[SDV.BV.AP]Life Sciences [q-bio]/Vegetal Biology/Plant breeding ,Rhamnogalacturonan-II ,Mutation ,MESH : Gene Expression Regulation, Plant - Abstract
International audience; BACKGROUND AND AIMSRhamnogalacturonan-II (RG-II) is one of the pectin motifs found in the cell wall of all land plants. It contains sugars such as 2-keto-3-deoxy-d-lyxo-heptulosaric acid (Dha) and 2-keto-3-deoxy-d-manno-octulosonic acid (Kdo), and within the wall RG-II is mostly found as a dimer via a borate diester cross-link. To date, little is known regarding the biosynthesis of this motif. Here, after a brief review of our current knowledge on RG-II structure, biosynthesis and function in plants, this study explores the implications of the presence of a Golgi-localized sialyltransferase-like 2 (SIA2) protein that is possibly involved in the transfer of Dha or Kdo in the RG-II of Arabidopsis thaliana pollen tubes, a fast-growing cell type used as a model for the study of cell elongation.METHODS:Two heterozygous mutant lines of arabidopsis (sia2-1+/- and qrt1 × sia2-2+/-) were investigated. sia2-2+/- was in a quartet1 background and the inserted T-DNA contained the reporter gene β-glucuronidase (GUS) under the pollen-specific promoter LAT52. Pollen germination and pollen tube phenotype and growth were analysed both in vitro and in vivo by microscopy.KEY RESULTS:Self-pollination of heterozygous lines produced no homozygous plants in the progeny, which may suggest that the mutation could be lethal. Heterozygous mutants displayed a much lower germination rate overall and exhibited a substantial delay in germination (20 h of delay to reach 30 % of pollen grain germination compared with the wild type). In both lines, mutant pollen grains that were able to produce a tube had tubes that were either bursting, abnormal (swollen or dichotomous branching tip) or much shorter compared with wild-type pollen tubes. In vivo, mutant pollen tubes were restricted to the style, whereas the wild-type pollen tubes were detected at the base of the ovary..CONCLUSIONS:This study highlights that the mutation in arabidopsis SIA2 encoding a sialyltransferase-like protein that may transfer Dha or Kdo on the RG-II motif has a dramatic effect on the stability of the pollen tube cell wall.
- Published
- 2014
47. Profile of 24-h Light Exposure and Circadian Phase of Melatonin Secretion in Night Workers
- Author
-
Jean Paquet, Dalila Benhaberou-Brun, and Marie Dumont
- Subjects
Adult ,Male ,0301 basic medicine ,medicine.medical_specialty ,Circadian phase ,Light ,Physiology ,Adaptation (eye) ,Melatonin ,03 medical and health sciences ,0302 clinical medicine ,Physiology (medical) ,Internal medicine ,Humans ,Medicine ,Circadian rhythm ,Melatonin secretion ,Light exposure ,business.industry ,Phase advance ,Significant difference ,Middle Aged ,Adaptation, Physiological ,Circadian Rhythm ,030104 developmental biology ,Endocrinology ,Female ,Sleep ,business ,030217 neurology & neurosurgery ,medicine.drug - Abstract
Light exposure was measured in 30 permanent night nurses to determine if specific light/dark profiles could be associated with a better circadian adaptation. Circadian adaptation was defined as a significant shift in the timing of the episode of melatonin secretion into the daytime. Light exposure was continuously recorded with ambulatory wrist monitors for 56 h, including 3 consecutive nights of work. Participants were then admitted to the laboratory for 24 h where urine was collected every 2 h under dim light for the determination of 6-sulphatoxymelatonin concentration. Cosinor analysis was used to estimate the phase position of the episode of melatonin secretion. Five participants showed a circadian adaptation by phase delay (“delayed participants”) and 3 participants showed a circadian adaptation by phase advance (“advanced participants”). The other 22 participants had a timing of melatonin secretion typical of day-oriented people (“nonshifters”). There was no significant difference between the 3 groups for total light exposure or for bright light exposure in the morning when traveling home. However, the 24-h profiles of light exposure were very distinctive. The timing of the main sleep episode was associated with the timing of light exposure. Delayed participants, however, slept in darker bedrooms, and this had a major impact on their profile of light/dark exposure. Delayed and advanced participants scored as evening and morning types, respectively, on a morningness-eveningness scale. This observation suggests that circadian phase prior to night work may contribute to the initial step toward circadian adaptation, later reinforced by specific patterns of light exposure.
- Published
- 2001
48. Sleep and wake disturbances following traumatic brain injury
- Author
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Pierre-Olivier Gaudreault, Valérie Mongrain, Samar Khoury, Caroline Arbour, Marie Dumont, Catherine Duclos, Catherine Wiseman-Hakes, Gilles Lavigne, Nadia Gosselin, Alex Desautels, and Université de Montréal. Faculté des arts et des sciences. Département de psychologie
- Subjects
medicine.medical_specialty ,Warfare ,Insomnia ,Traumatic brain injury ,Poison control ,Disorders of Excessive Somnolence ,Chronobiology Disorders ,Endocrine System Diseases ,Wounds, Nonpenetrating ,Occupational safety and health ,Physical medicine and rehabilitation ,Blast Injuries ,Intervention (counseling) ,Injury prevention ,medicine ,Humans ,Hypnotics and Sedatives ,Circadian rhythms ,Psychiatry ,Sleep-wake disturbances ,Melatonin ,Hypersomnia ,Inpatients ,Cognitive Behavioral Therapy ,business.industry ,Human factors and ergonomics ,General Medicine ,medicine.disease ,nervous system diseases ,Hospitalization ,Sleep Disorders, Intrinsic ,Military Personnel ,nervous system ,Brain Injuries ,Etiology ,Brain Damage, Chronic ,medicine.symptom ,business ,Sleep - Abstract
Traumatic brain injury (TBI) is a major health concern in industrialised countries. Sleep and wake disturbances are among the most persistent and disabling sequelae after TBI. Yet, despite the widespread complaints of post-TBI sleep and wake disturbances, studies on their etiology, pathophysiology, and treatments remain inconclusive. This narrative review aims to summarise the current state of knowledge regarding the nature of sleep and wake disturbances following TBI, both subjective and objective, spanning all levels of severity and phases post-injury. A second goal is to outline the various causes of post-TBI sleep-wake disturbances. Globally, although sleep-wake complaints are reported in all studies and across all levels of severity, consensus regarding the objective nature of these disturbances is not unanimous and varies widely across studies. In order to optimise recovery in TBI survivors, further studies are required to shed light on the complexity and heterogeneity of post-TBI sleep and wake disturbances, and to fully grasp the best timing and approach for intervention.
- Published
- 2013
49. Time course of narrow frequency bands in the waking EEG during sleep deprivation
- Author
-
Marie Dumont, Marc Hébert, M Mila Macchi, Julie Carrier, and Chantal Lafrance
- Subjects
Adult ,Male ,medicine.medical_specialty ,Time Factors ,media_common.quotation_subject ,Electroencephalography ,Audiology ,Radio spectrum ,Body Temperature ,medicine ,Humans ,Circadian rhythm ,Wakefulness ,media_common ,medicine.diagnostic_test ,General Neuroscience ,Similar time ,Circadian Rhythm ,Electrophysiology ,Sleep deprivation ,Anesthesia ,Time course ,Sleep Deprivation ,Female ,Sleep Stages ,medicine.symptom ,Psychology ,Vigilance (psychology) - Abstract
Electroencephalograms (EEGs) of 14 normal subjects were recorded every 2 h during 38 h constant routines. Adjacent narrow frequency bands (NFB) with similar temporal trends were grouped into frequency clusters. Clusters I (2.00-7.75 Hz) and III (11.00-14.75 Hz) exhibited similar time courses which may reflect both the duration of time awake and a circadian modulation. Cluster II (8.00-10.75 Hz) was characterized by a time course similar to the circadian modulation of core body temperature. Cluster V (18.00-24.75 Hz) was correlated with subjective sleepiness and may reflect the increasing effort made by subjects to perform the task as sleep deprivation lengthened. Various NFB in the waking EEG may reflect different physiological mechanisms underlying variations in vigilance states.
- Published
- 1999
50. Daytime Vigilance after Morning Bright Light Exposure in Volunteers Subjected to Sleep Restriction
- Author
-
Chantal Lambert, Paul Lespérance, Chantal Lafrance, and Marie Dumont
- Subjects
Adult ,Male ,medicine.medical_specialty ,Daytime ,Polysomnography ,media_common.quotation_subject ,Experimental and Cognitive Psychology ,Arousal ,Melatonin ,Behavioral Neuroscience ,Internal medicine ,Reaction Time ,medicine ,Humans ,Attention ,Wakefulness ,Sleep restriction ,Morning ,media_common ,Phototherapy ,medicine.disease ,Privation ,Circadian Rhythm ,Alertness ,Endocrinology ,Sleep Deprivation ,Female ,Sleep Stages ,Psychology ,Vigilance (psychology) ,medicine.drug - Abstract
This study was designed to test the hypothesis that bright light (BL) can have a stimulating effect on vigilance even in the absence of suppression of melatonin secretion and that this effect can be detected when measured in subjects with low vigilance levels. Seven normal subjects were exposed to bright-white light (BL group) and seven to dim-red light (DL group) on 2 consecutive days, each following a night of 4-h sleep restriction. The light treatment was administered in the late morning, between 0900 and 1330 hours. Salivary melatonin measurements indicated that BL did not suppress melatonin secretion or induce circadian phase shifts. The effects of the two treatments were compared on validated measures of daytime vigilance: immediate effects were evaluated on subjective alertness during the light treatment, whereas short-term (0.5–10.5 h) and long-term (20.5–34.5 h) carryover effects were measured on subjective alertness, daytime sleep latencies (DSL), and psychomotor performance. After two nights of sleep restriction, subjective alertness and daytime sleep latencies decreased significantly, but there was no effect of the light treatment. BL treatment did not affect global performance, but there was an effect on the strategy used by the subjects, as shown by faster reaction times and increased percentage of errors in the BL group. It was concluded that daytime BL exposure did not have a stimulating effect on our measures of vigilance even in sleep-deprived subjects but that it may increase physiological arousal and affect the subjects’ behavior in some specific performance tasks.
- Published
- 1998
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