30 results on '"Langlet, C."'
Search Results
2. Impact of Spontaneous Cries on the Physiological Well-Being and the Cerebral Oxygenation of Children Born Very Preterm
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Zores, C Koenig, primary, Pebayle, T, additional, Hoeft, A, additional, Langlet, C, additional, Escande, B, additional, Astruc, D, additional, Dufour, A, additional, and Kuhn, P, additional
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- 2011
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3. End of Life in the Neonatal Period: Effect of the Leonetti's Law on Practices in a French NICU
- Author
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Litzler-Renault, S, primary, Desprez, P, additional, Escande, B, additional, Langlet, C, additional, Matis, J, additional, Astruc, D, additional, and Kuhn, P, additional
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- 2011
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4. Do Infants Born Very Preterm React to Nosocomial Odors Present in their Incubators? Evidence from Physiologic Data
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Kuhn, P, primary, Pebayle, T, additional, Langlet, C, additional, Astruc, D, additional, and Marlier, L, additional
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- 2011
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5. Mid-Lumbar Segments Are Needed for the Expression of Locomotion in Chronic Spinal Cats
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Langlet, C., primary, Leblond, H., additional, and Rossignol, S., additional
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- 2005
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6. Direct stimulation of Vav guanine nucleotide exchange activity for Ras by phorbol esters and diglycerides.
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Gulbins, E, primary, Coggeshall, K M, additional, Baier, G, additional, Telford, D, additional, Langlet, C, additional, Baier-Bitterlich, G, additional, Bonnefoy-Berard, N, additional, Burn, P, additional, Wittinghofer, A, additional, and Altman, A, additional
- Published
- 1994
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7. Activation of Ras in vitro and in intact fibroblasts by the Vav guanine nucleotide exchange protein
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Gulbins, E, primary, Coggeshall, K M, additional, Langlet, C, additional, Baier, G, additional, Bonnefoy-Berard, N, additional, Burn, P, additional, Wittinghofer, A, additional, Katzav, S, additional, and Altman, A, additional
- Published
- 1994
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8. Vidéo-essais : la vidéo-critique cinématographique et littéraire comme outil pédagogique
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Guido Mattia Gallerani, Federico Pagello, I. Langlet, C. Conant-Ouaked, Gallerani Guido Mattia, and Pagello Federico
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analyse littéraire ,analyse filmique ,Essai ,Vidéo-essai ,pédagogie innovative - Abstract
Le débat sur les nouvelles formes de critique et de recherche, universitaires ou non, se polarise à la fois sur les fonctions du numérique, à savoir son action de deep remixability, qui selon Lev Manovich identifie la spécificité des logiciels de rendre tout type de langage, et sur la prédominance conservée, même dans un contexte médiatique, par les stratégies expressives et argumentatives de l’écriture. Notre objectif est d’étudier l’apparition du numérique et les possibilités critiques et pédagogiques qu’il apporte à un genre qui a développé, au cours de l’histoire, la fonction de la critique et de la recherche. Tout en considérant la collaboration entre le visuel et l’écriture, nous voulons montrer que le vidéo-essai – cette typologie d’essai médiatique – ne se base ni sur la prédominance du visuel, ni sur la simple présence d’une argumentation, mais plutôt sur la relation critique entre les sources commentées (aussi bien visuelles qu’écrites) et une voix de commentaire qui est, elle aussi, technologisée par les logiciels.
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- 2022
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9. The reaction to xenografts exchanged between different nemertine species of the same genus Lineus is an active immune response
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Langlet, C. and Bierne, J.
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- 1986
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10. Thymus-like intestine in the marine nemerten [formula omitted][formula omitted]
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Bierne, J., Brossard, D., and Langlet, C.
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- 1989
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11. 10.6 Late graft-versus-host disease in allografted Lineus ruber
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Bierne, J. and Langlet, C.
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- 1989
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12. Reactions of [formula omitted] to orthorectids in various stages of development
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Langlet, C. and Bierne, J.
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- 1989
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13. A framework to improve the alignment of individual cytoarchitectonic maps of the Julich-Brain atlas using cortical folding landmarks.
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Wang X, Leprince Y, Lebenberg J, Langlet C, Mohlberg H, Rivière D, Auzias G, Dickscheid T, Amunts K, and Mangin JF
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- Autopsy, Magnetic Resonance Imaging methods, Brain Mapping methods, Brain, Neuroimaging
- Abstract
The segregation of the cortical mantle into cytoarchitectonic areas provides a structural basis for the specialization of different brain regions. In vivo neuroimaging experiments can be linked to this postmortem cytoarchitectonic parcellation via Julich-Brain. This atlas embeds probabilistic maps that account for inter-individual variability in the localization of cytoarchitectonic areas in the reference spaces targeted by spatial normalization. We built a framework to improve the alignment of architectural areas across brains using cortical folding landmarks. This framework, initially designed for in vivo imaging, was adapted to postmortem histological data. We applied this to the first 14 brains used to establish the Julich-Brain atlas to infer a refined atlas with more focal probabilistic maps. The improvement achieved is significant in the primary regions and some of the associative areas. This framework also provides a tool for exploring the relationship between cortical folding patterns and cytoarchitectonic areas in different cortical regions to establish new landmarks in the remainder of the cortex., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
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- 2024
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14. Changes of Infant- and Family-Centered Care Practices Administered to Extremely Preterm Infants During Implementation of the NIDCAP Program.
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Klein V, Zores-Koenig C, Dillenseger L, Langlet C, Escande B, Astruc D, Le Ray I, and Kuhn P
- Abstract
Introduction: Many studies have evaluated the Neonatal Individualized Developmental Care and Assessment Program (NIDCAP), but few studies have assessed changes in infant- and family-centered developmental care (IFCDC) practices during its implementation. Objectives: The primary objective of this single center study was to investigate the impact of the implementation of the NIDCAP program on IFCDC practices used for management of extremely preterm infants (EPIs). The secondary objective was to determine during implementation the impact of this program on the short-term medical outcomes of all EPIs hospitalized at our center. Methods: All EPIs (<28 weeks gestational age) who were hospitalized at Strasbourg University Hospital from 2007 to 2014 were initially included. Outborn infants were excluded. The data of EPIs were compared for three time periods: 2007 to 2008 (pre-NIDCAP), 2010 to 2011, and 2013 to 2014 (during-NIDCAP implementation) using appropriate statistical tests. The clinical and caring procedures used during the first 14 days of life were analyzed, with a focus on components of individualized developmental care (NIDCAP observations), infant pain management (number of painful procedures, clinical pain assessment), skin-to-skin contact (SSC; frequency, day of initiation, and duration), and family access and involvement in the care of their children (duration of parental presence, parental participation in care). The short-term mortality and morbidity at discharge were evaluated. Results: We examined 228 EPIs who received care during the three time periods. Over time, painful procedures decreased, but pain evaluations, parental involvement in care, individualized observations, and SSC increased (all p < 0.01). In addition, the first SSC was performed earlier ( p = 0.03) and lasted longer ( p < 0.01). There were no differences in mortality and morbidity, but there were reductions in the duration of mechanical ventilation ( p = 0.02) and the time from birth to first extubation ( p = 0.02), and an increase of weight gain at discharge ( p = 0.02). Conclusion: NIDCAP implementation was accompanied by progressive, measurable, and significant changes in IFCDC strategies. There were, concomitantly, moderate but statistically significant improvements in multiple important outcome measures of all hospitalized EPI., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Klein, Zores-Koenig, Dillenseger, Langlet, Escande, Astruc, Le Ray, Kuhn and Strasbourg NIDCAP Study group.)
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- 2021
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15. Favorable outcomes among neonates not separated from their symptomatic SARS-CoV-2-infected mothers.
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Martenot A, Labbassi I, Delfils-Stern A, Monroy O, Langlet C, Pichault-Klein V, Delagreverie H, De Marcillac F, Fafi-Kremer S, Deruelle P, and Kuhn P
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- Adult, Breast Feeding, COVID-19 virology, Female, Humans, Infant Food, Infant, Newborn, Retrospective Studies, SARS-CoV-2 isolation & purification, COVID-19 physiopathology, Mothers, Outcome Assessment, Health Care
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- 2021
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16. High-Frequency Sensorineural Hearing Loss Alters Cue-Weighting Strategies for Discriminating Stop Consonants in Noise.
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Varnet L, Langlet C, Lorenzi C, Lazard DS, and Micheyl C
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- Adult, Aged, Cues, Female, Hearing Aids, Humans, Male, Middle Aged, Noise, Young Adult, Hearing Loss, High-Frequency pathology, Hearing Loss, Sensorineural pathology, Persons with Hearing Disabilities statistics & numerical data, Speech Perception
- Abstract
There is increasing evidence that hearing-impaired (HI) individuals do not use the same listening strategies as normal-hearing (NH) individuals, even when wearing optimally fitted hearing aids. In this perspective, better characterization of individual perceptual strategies is an important step toward designing more effective speech-processing algorithms. Here, we describe two complementary approaches for (a) revealing the acoustic cues used by a participant in a /d/-/g/ categorization task in noise and (b) measuring the relative contributions of these cues to decision. These two approaches involve natural speech recordings altered by the addition of a “bump noise.” The bumps were narrowband bursts of noise localized on the spectrotemporal locations of the acoustic cues, allowing the experimenter to manipulate the consonant percept. The cue-weighting strategies were estimated for three groups of participants: 17 NH listeners, 18 HI listeners with high-frequency loss, and 15 HI listeners with flat loss. HI participants were provided with individual frequency-dependent amplification to compensate for their hearing loss. Although all listeners relied more heavily on the high-frequency cue than on the low-frequency cue, an important variability was observed in the individual weights, mostly explained by differences in internal noise. Individuals with high-frequency loss relied slightly less heavily on the high-frequency cue relative to the low-frequency cue, compared with NH individuals, suggesting a possible influence of supra-threshold deficits on cue-weighting strategies. Altogether, these results suggest a need for individually tailored speech-in-noise processing in hearing aids, if more effective speech discriminability in noise is to be achieved.
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- 2019
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17. Early Inflammatory Markers for the Diagnosis of Late-Onset Sepsis in Neonates: The Nosodiag Study.
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Dillenseger L, Langlet C, Iacobelli S, Lavaux T, Ratomponirina C, Labenne M, Astruc D, Severac F, Gouyon JB, and Kuhn P
- Abstract
Background: Early diagnosis is essential to improve the treatment and prognosis of newborn infants with nosocomial bacterial infections. Although cytokines and procalcitonin (PCT) have been evaluated as early inflammatory markers, their diagnostic properties have rarely been compared. Objectives: This study evaluated and compared the ability of individual inflammatory markers available for clinician (PCT, semi-quantitative determination of IL-8) and of combinations of markers (CRP
i plus IL-6 or quantitative or semi-quantitative determination of IL-8) to diagnose bacterial nosocomial infections in neonates. Methods: This prospective two-center study included neonates suspected of nosocomial infections from September 2008 to January 2012. Inflammatory markers were measured initially upon suspicion of nosocomial infection, and CRP was again measured 12-24 h later. Newborns were retrospectively classified into two groups: those who were infected (certainly or probably) and uninfected (certainly or probably). Results: The study included 130 infants of median gestational age 28 weeks (range, 24-41 weeks). Of these, 34 were classified as infected and 96 as uninfected. The sensitivity, specificity, positive and negative predictive values (PPV and NPV), and positive and negative likelihood ratios (LR+ and LR-) for PCT were 59.3% (95% confidence interval [CI], 38.8-77.6%), 78.5% (95% CI, 67.8-86.9%), 48.5% (95% CI, 30.8-66.5%), 84.9% (95% CI, 74.6-92.2%), 2.7 (95% CI, 1.6-4.9), and 0.5 (95% CI, 0.3-0.8), respectively. Semi-quantitative IL-8 had the highest specificity (92.19%; 95% CI, 82.70-97.41%), PPV (72.22%; 95% CI, 46.52-90.30%) and LR+ (6.17, 95% CI, 2.67-28.44), but had low specificity (48.15%; 95% CI, 28.67-68.05%). Of all markers tested, the combination of IL-6 and CRPi had the highest sensitivity (78.12%; 95% CI, 60.03-90.72%), NPV (91.3%; 95% CI, 82.38-96.32%) and LR- (0.29; 95% CI, 0.12-0.49). The combination of IL-6 and CRPi had a higher area under the curve than PCT, but with borderline significance ( p = 0.055). Conclusions: The combination of IL-6 and CRPi was superior to other methods, including PCT, for the early diagnosis of nosocomial infection in neonates, but was not sufficient for sole use. The semi-quantitative determination of IL-8 had good diagnostic properties but its sensitivity was too low for use in clinical practice.- Published
- 2018
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18. Occupational exposure to chrome VI compounds in French companies: results of a national campaign to measure exposure (2010-2013).
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Vincent R, Gillet M, Goutet P, Guichard C, Hédouin-Langlet C, Frocaut AM, Lambert P, Leray F, Mardelle P, Dorotte M, and Rousset D
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- Carcinogens analysis, Environmental Monitoring instrumentation, France, Humans, Inhalation Exposure analysis, Manufacturing Industry, Maximum Allowable Concentration, Occupational Health, Paint, Threshold Limit Values, Workplace, Air Pollutants, Occupational analysis, Chromium analysis, Environmental Monitoring methods, Occupational Exposure analysis
- Abstract
A campaign to measure exposure to hexavalent chromium compounds was carried out in France by the seven CARSAT chemistry laboratories, CRAMIF laboratory, and INRS over the 2010-2013 period. The survey included 99 companies involved in various activity sectors. The inhalable fraction of airborne particles was sampled, and exposure levels were determined using ion chromatography analysis combined with post-column derivatization and UV detection. The quality of the measurement results was guaranteed by an inter-laboratory comparison system involving all the laboratories participating in this study. Exposure levels frequently exceeded the French occupational exposure limit value (OELV) of 1 µg m(-3), in activities such as thermal metallization and manufacturing and application of paint in the aeronautics sector. The results also reveal a general trend for a greater proportion of soluble Chromium VI (Cr VI) compounds compared with insoluble compounds. Qualitative and quantitative information relating to the presence of other metallic compounds in the air of workplaces is also provided, for example for Cr III, Ni, Fe, etc. The sampling strategy used and the measurement method are easy to implement, making it possible to check occupational exposure with a view to comparing it to an 8 h-OELV of 1 µg m(-3)., (© The Author 2014. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.)
- Published
- 2015
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19. Infants born very preterm react to variations of the acoustic environment in their incubator from a minimum signal-to-noise ratio threshold of 5 to 10 dBA.
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Kuhn P, Zores C, Pebayle T, Hoeft A, Langlet C, Escande B, Astruc D, and Dufour A
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- Acoustics, Behavior, Birth Weight, Blood Pressure, Environment, Female, Heart Rate, Humans, Infant, Infant, Newborn, Infant, Premature physiology, Intensive Care, Neonatal methods, Male, Noise, Oxygen metabolism, Pressure, Respiration, Artificial, Signal-To-Noise Ratio, Time Factors, Video Recording, Hearing physiology, Sound
- Abstract
Introduction: Very early preterm infants (VPIs) are exposed to unpredictable noise in neonatal intensive care units. Their ability to perceive moderate acoustic environmental changes has not been fully investigated., Results: Physiological values of the 598 isolated sound peaks (SPs) that were 5-10 and 10-15 dB slow-response A (dBA) above background noise levels and that occurred during infants' sleep varied significantly, indicating that VPIs detect them. Exposure to 10-15 dBA SPs during active sleep significantly increased mean heart rate and decreased mean respiratory rate and mean systemic and cerebral oxygen saturations relative to baseline., Discussion: VPIs are sensitive to changes in their nosocomial acoustic environment, with a minimal signal-to-noise ratio (SNR) threshold of 5-10 dBA. These acoustic changes can alter their well-being., Methods: In this observational study, we evaluated their differential auditory sensitivity to sound-pressure level (SPL) increments below 70-75 dBA equivalent continuous level in their incubators. Environmental (SPL and audio recording), physiological, cerebral, and behavioral data were prospectively collected over 10 h in 26 VPIs (GA 28 (26-31) wk). SPs emerging from background noise levels were identified and newborns' arousal states at the time of SPs were determined. Changes in parameters were compared over 5-s periods between baseline and the 40 s following the SPs depending on their SNR thresholds above background noise.
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- 2012
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20. N-glycans of core2 beta(1,6)-N-acetylglucosaminyltransferase-I (C2GnT-I) but not those of alpha(1,3)-fucosyltransferase-VII (FucT-VII) are required for the synthesis of functional P-selectin glycoprotein ligand-1 (PSGL-1): effects on P-, L- and E-selectin binding.
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Prorok-Hamon M, Notel F, Mathieu S, Langlet C, Fukuda M, and El-Battari A
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- Animals, Cell Line, Cricetinae, Fucosyltransferases chemistry, Fucosyltransferases genetics, Fucosyltransferases metabolism, Gene Expression Regulation, Enzymologic, Glycosylation, Humans, Mutation, N-Acetylglucosaminyltransferases genetics, Protein Binding, E-Selectin metabolism, L-Selectin metabolism, Membrane Glycoproteins biosynthesis, N-Acetylglucosaminyltransferases chemistry, N-Acetylglucosaminyltransferases metabolism, P-Selectin metabolism, Polysaccharides metabolism
- Abstract
C2GnT-I [core2 beta(1,6)-N-acetyglucosaminyltransferase-I] and FucT-VII [alpha(1,3)-fucosyltransferase-VII] are the key enzymes for the biosynthesis of sialyl-Lewis x determinants on selectin ligands and therefore they represent good drug targets for the treatment of inflammatory disorders and other pathologies involving selectins. In the present study, we examined the importance of N-glycosylation for the ability of C2GnT-I and FucT-VII to generate functional selectin ligands, particularly the PSGL-1 (P-selectin glycoprotein ligand-1). We found that (i) both enzymes have their two N-glycosylation sites occupied, (ii) for C2GnT-I, the N-glycan chain linked to Asn-95 significantly contributes to the synthesis of functional PSGL-1 and is required to localize the enzyme to the cis/medial-Golgi compartment, (iii) all N-glycosylation-deficient proteins of FucT-VII displayr a dramatic impairment of their in vitro enzymatic activities, but retain their ability to fucosylate the core2-modified PSGL-I and to generate P- and L-selectin binding, and (iv) the glycomutants of FucT-VII fail to synthesize sialyl-Lewis x or to generate E-selectin binding unless core2-modified PSGL-1 is present. All combined, our results show a differential functional impact of N-glycosylation on C2GnT-1 and FucT-VII and disclose that a strongly reduced FucT-VII activity retains the ability to fucosylate PSGL-1 on the core2-based binding site(s) for the three selectins.
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- 2005
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21. Contribution of the carboxyl terminus of the VPAC1 receptor to agonist-induced receptor phosphorylation, internalization, and recycling.
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Langlet C, Langer I, Vertongen P, Gaspard N, Vanderwinden JM, and Robberecht P
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- Adenylyl Cyclases metabolism, Amino Acid Sequence, Animals, Antibodies, Monoclonal chemistry, Blotting, Western, CHO Cells, Cell Line, Cell Membrane metabolism, Cricetinae, Cyclic AMP chemistry, Endosomes metabolism, Flow Cytometry, Humans, Immunoprecipitation, Ligands, Microscopy, Confocal, Molecular Sequence Data, Monensin chemistry, Mutation, Peptides chemistry, Phosphorylation, Point Mutation, Protein Binding, Protein Structure, Tertiary, Protein Transport, Receptors, Vasoactive Intestinal Peptide metabolism, Receptors, Vasoactive Intestinal Polypeptide, Type I, Serine chemistry, Time Factors, Vasoactive Intestinal Peptide chemistry, Receptors, Vasoactive Intestinal Peptide chemistry, Receptors, Vasoactive Intestinal Peptide physiology
- Abstract
When exposed to vasoactive intestinal peptide (VIP), the human wild type VPAC1 receptor expressed in Chinese hamster ovary (CHO) cells is rapidly phosphorylated, desensitized, and internalized in the endosomal compartment and is not re-expressed at the cell membrane within 2 h after agonist removal. The aims of the present work were first to correlate receptor phosphorylation level to internalization and recycling, measured by flow cytometry and in some cases by confocal microscopy using a monoclonal antibody that did not interfere with ligand binding, and second to identify the phosphorylated Ser/Thr residues. Combining receptor mutations and truncations allowed identification of Ser250 (in the second intracellular loop), Thr429, Ser435, Ser448 or Ser449, and Ser455 (all in the distal part of the C terminus) as candidates for VIP-stimulated phosphorylation. The effects of single mutations were not additive, suggesting alternative phosphorylation sites in mutated receptors. Replacement of all of the Ser/Thr residues in the carboxyl-terminal tail and truncation of the domain containing these residues completely inhibited VIP-stimulated phosphorylation and receptor internalization. There was, however, no direct correlation between receptor phosphorylation and internalization; in some truncated and mutated receptors, a 70% reduction in phosphorylation had little effect on internalization. In contrast to results obtained on the wild type and all of the mutated or truncated receptors that still underwent phosphorylation, internalization of the severely truncated receptor was reversed within 2 h of incubation in the absence of the agonist. Receptor recovery was blocked by monensin, an endosome inhibitor.
- Published
- 2005
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22. Effect of inactivating mutations on phosphorylation and internalization of the human VPAC2 receptor.
- Author
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Langer I, Langlet C, and Robberecht P
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- Adenylyl Cyclases metabolism, Amino Acid Sequence, Animals, CHO Cells, Calcium metabolism, Cricetinae, Cyclic AMP analogs & derivatives, Cyclic AMP metabolism, Enzyme Activation, Enzyme Inhibitors metabolism, Humans, Molecular Sequence Data, Phosphorylation, Protein Structure, Tertiary, Receptors, Vasoactive Intestinal Peptide agonists, Receptors, Vasoactive Intestinal Peptide chemistry, Receptors, Vasoactive Intestinal Peptide, Type II, Vasoactive Intestinal Peptide metabolism, Endocytosis physiology, Mutation, Receptors, Vasoactive Intestinal Peptide genetics, Receptors, Vasoactive Intestinal Peptide metabolism
- Abstract
The VPAC(2) receptor, as all members of the G-protein-coupled receptor (GPCR)-B family, has two highly conserved motifs in the third intracellular (IC(3)) loop: a lysine and a leucine located at the amino-terminus and two basic residues separated by a leucine and an alanine at the carboxyl-terminus. This study evaluates the involvement of those conserved amino acid sequences in VPAC(2) signal transduction and regulation. The residues were mutated into alanine and mutants were expressed in Chinese hamster ovary (CHO) cells stably transfected with Galpha16 and aequorin. Mutation of L310 reduced efficacy of vasoactive intestinal polypeptide (VIP) to stimulate adenylate cyclase activity through Galphas coupling by 75%, without affecting VIP capability to stimulate an increase in [Ca(2+)](i) through Galpha16 coupling. Mutation of R325 and, to a lesser extend, K328 reduced VIP efficacy to stimulate [Ca(2+)](i) increase and VIP potency to stimulate adenylate cyclase. The combination of mutations of both amino- and carboxyl-terminus located conserved motifs of the IC(3) loop generates an inactive receptor with respect to [Ca(2+)](i) increase and adenylate cyclase activation, but also with respect to receptor phosphorylation and internalization that were indeed directly correlated with the potency of inactivation of the receptors. The amino-terminus of the VPAC(2) receptor IC(3) loop is thus involved in adenylate cyclase activation and the carboxyl-terminus of the IC(3) loop participates in both Galphas and Galpha16 coupling. The mutations studied also reduced both receptor phosphorylation and internalization in a manner that appeared directly linked to the alteration of Galphas and Galpha16 coupling.
- Published
- 2005
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23. Intramural bronchogenic cyst in the carina observed in a neonate and treated by needle aspiration: a case report.
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Gaugler C, Donato L, Rivera S, Langlet C, Chognot D, and Messer J
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- Biopsy, Needle, Bronchogenic Cyst therapy, Bronchoscopy, Female, Humans, Infant, Newborn, Bronchogenic Cyst diagnosis
- Abstract
We report the first case to be observed in a neonate of an intramural bronchogenic cyst in the carina. Considering the age of the infant, it was decided to administer curative treatment by needle aspiration. A rigid bronchoscopy was used. The outcome was favorable.
- Published
- 2004
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24. Neonatal necrotizing tracheobronchitis: three case reports.
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Gaugler C, Astruc D, Donato L, Rivera S, Langlet C, and Messer J
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- Airway Obstruction etiology, Bronchitis pathology, Bronchoscopy, Female, Humans, Infant, Newborn, Intubation, Intratracheal, Male, Necrosis, Tracheitis pathology, Bronchitis etiology, Respiration, Artificial adverse effects, Tracheitis etiology
- Abstract
Necrotizing tracheobronchitis is a serious affection observed in ventilated newborns, frequently infants with instable hemodynamic state. It is characterized by acute episodes of airway obstruction. The treatment consists of the desobstruction by rigid bronchoscopy. The vascular theory seems to be of utmost importance in the physiopathology. Three cases are reported.
- Published
- 2004
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25. Dynamic recruitment of the adaptor protein LAT: LAT exists in two distinct intracellular pools and controls its own recruitment.
- Author
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Bonello G, Blanchard N, Montoya MC, Aguado E, Langlet C, He HT, Nunez-Cruz S, Malissen M, Sanchez-Madrid F, Olive D, Hivroz C, and Collette Y
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- Animals, Base Sequence, Carrier Proteins genetics, Cell Compartmentation, Cell Line, DNA genetics, Humans, Intracellular Fluid metabolism, Jurkat Cells, Lymphocyte Activation, Membrane Proteins genetics, Mice, Phosphoproteins genetics, Receptors, Antigen, T-Cell metabolism, Recombinant Fusion Proteins genetics, Recombinant Fusion Proteins metabolism, Signal Transduction, T-Lymphocytes immunology, T-Lymphocytes metabolism, Adaptor Proteins, Signal Transducing, Carrier Proteins metabolism, Membrane Proteins metabolism, Phosphoproteins metabolism
- Abstract
The integral membrane adaptor protein linker for activation of T cells (LAT) couples the T-cell receptor (TCR) with downstream signalling and is essential for T-cell development and activation. Here, we investigate the dynamic distribution of LAT-GFP fusion proteins by time-lapse video imaging of live T lymphocytes interacting with antigen-presenting cells. We show that LAT forms two distinct cellular pools, one at the plasma membrane and one that co-distributes with transferrin-labelled intracellular compartments also containing the TCR/CD3-associated zeta chain. The distribution of LAT between these two pools is dependent on LAT intracytoplasmic residues. Whereas plasma membrane-associated LAT is recruited to immune synapses after a few seconds of cell conjugate formation, the intracellular pool is first polarized and then recruited after a few minutes. We further show that LAT intracytoplasmic amino acid residues, particularly the Tyr136, 175, 195 and 235 residues, are required for its own recruitment to the immune synapse and that a herein-identified juxtamembrane LAT region (amino acids 32-104) is involved in the localization of LAT in intracellular pools and in T-cell signalling. Altogether, our results demonstrate that LAT controls its own recruitment at the immune synapse, where it is required as a scaffold protein for the signalling machinery. The results also suggest that the intracellular pool of LAT might be required for T-cell activation.
- Published
- 2004
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26. Transgene expression of alpha(1,2)-fucosyltransferase-I (FUT1) in tumor cells selectively inhibits sialyl-Lewis x expression and binding to E-selectin without affecting synthesis of sialyl-Lewis a or binding to P-selectin.
- Author
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Mathieu S, Prorok M, Benoliel AM, Uch R, Langlet C, Bongrand P, Gerolami R, and El-Battari A
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- Animals, CA-19-9 Antigen, Cell Adhesion physiology, Endothelial Cells physiology, Flow Cytometry, Fluorescence, Fucosyltransferases genetics, Gangliosides metabolism, Genetic Vectors, HIV-1 genetics, HT29 Cells, Humans, Immunoblotting, Membrane Glycoproteins metabolism, Oligosaccharides metabolism, P-Selectin metabolism, Sialyl Lewis X Antigen, Transduction, Genetic, Transfection, Transgenes, E-Selectin metabolism, Fucosyltransferases biosynthesis, Oligosaccharides biosynthesis
- Abstract
During inflammation, E- and P-selectins appear on activated endothelial cells to interact with leukocytes through sialyl-Lewis x and sialyl-Lewis a antigens (sLe(x/a)). These selectins can also interact with tumor cells in a sialyl-Lewis-dependent manner and for this reason, they are thought to play a key role in metastasis. Diverting the biosynthesis of sialyl-Lewis antigens toward nonadhesive structures is an attractive gene therapy for preventing the hematogenous metastatic spread of cancers. We have previously shown that transfection of alpha(1,2)-fucosyltransferase-I (FUT1) in Chinese hamster ovary (CHO) cells had a slight effect on the overall sialylation while the synthesis of sLE(x) was dramatically prevented. We herein delivered the gene of FUT1 by a human immunodeficiency virus-derived lentiviral vector to three human cancer cell lines including pancreatic (BxPC3), hepatic (HepG2), and colonic (HT-29) cancer cells. We found that on FUT1 transduction, all cells exhibited a dramatic decrease in sLe(x) synthesis with a concomitant increase in Le(y) and Le(b) expression, without any detectable effect on the level of cell surface sLe(a) antigens. In parallel, FUT1-transduced HT-29 and HepG2 cells, but not BxPC3 cells, failed to interact with E-selectin as assessed by E-selectin-binding assay or dynamic adhesion to activated endothelial cells. We show also that transduced FUT1 efficiently fucosylates the P-selectin ligand PSGL-1 without altering P-selectin binding. These results have important implications for understanding cell-specific reactions underlying the synthesis of selectin ligands in cancer cells and may provide a basis for the development of anti-metastatic gene therapy.
- Published
- 2004
- Full Text
- View/download PDF
27. TCR signal initiation machinery is pre-assembled and activated in a subset of membrane rafts.
- Author
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Drevot P, Langlet C, Guo XJ, Bernard AM, Colard O, Chauvin JP, Lasserre R, and He HT
- Subjects
- CD4 Antigens metabolism, Cell Line, Detergents, Humans, Plant Oils, Polyethylene Glycols, Protein-Tyrosine Kinases metabolism, Solubility, ZAP-70 Protein-Tyrosine Kinase, Membrane Microdomains metabolism, Receptor-CD3 Complex, Antigen, T-Cell metabolism, Signal Transduction
- Abstract
Recent studies suggest that rafts are involved in numerous cell functions, including membrane traffic and signaling. Here we demonstrate, using a polyoxyethylene ether Brij 98, that detergent-insoluble microdomains possessing the expected biochemical characteristics of rafts are present in the cell membrane at 37 degrees C. After extraction, these microdomains are visualized as membrane vesicles with a mean diameter of approximately 70 nm. These findings provide further evidence for the existence of rafts under physiological conditions and are the basis of a new isolation method allowing more accurate analyses of raft structure. We found that main components of T cell receptor (TCR) signal initiation machinery, i.e. TCR-CD3 complex, Lck and ZAP-70 kinases, and CD4 co-receptor are constitutively partitioned into a subset of rafts. Functional studies in both intact cells and isolated rafts showed that upon ligation, TCR initiates the signaling in this specialized raft subset. Our data thus strongly indicate an important role of rafts in organizing TCR early signaling pathways within small membrane microdomains, both prior to and following receptor engagement, for efficient TCR signal initiation upon stimulation.
- Published
- 2002
- Full Text
- View/download PDF
28. The cytosolic and transmembrane domains of the beta 1,6 N-acetylglucosaminyltransferase (C2GnT) function as a cis to medial/Golgi-targeting determinant.
- Author
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Zerfaoui M, Fukuda M, Langlet C, Mathieu S, Suzuki M, Lombardo D, and El-Battari A
- Subjects
- Animals, Base Sequence, CHO Cells, Catalytic Domain, Cricetinae, DNA Primers, Fucose metabolism, Fucosyltransferases, Microscopy, Fluorescence, N-Acetylglucosaminyltransferases chemistry, Cell Membrane enzymology, Cytosol enzymology, Golgi Apparatus enzymology, N-Acetylglucosaminyltransferases metabolism
- Abstract
The beta 1,6 N-acetylglucosaminyltransferase (C2GnT) has been recently mapped to the cis/medial-Golgi compartment. To analyze the Golgi-targeting determinants of C2GnT, we constructed various deletion mutants of the enzyme fused to the enhanced green fluorescent protein (EGFP) and localized these proteins by fluorescence microscopy in living cells. We found that the N-terminal peptide encompassing amino acids 1 to 32 represents the minimal Golgi-targeting signal sufficient to localize EGFP to the same compartment as the full-length C2GnT. This peptide makes up the cytoplasmic and the transmembrane domains of the enzyme and was referred to as CTd (cytoplasmic and transmembrane domains). We compared the Golgi-targeting efficiency of the C2GnT-derived CTd with its homologous domains from other glycosyltransferases, including the H-type alpha(1,2)-fucosyltransferase (FucTI), the polypeptide N-acetylgalactosaminyltransferase-I (GalNAcT-I), the alpha(1,3)-fucosyltransferase VII (FucTVII), and the alpha(2,6)-sialyltransferase (ST6Gal-I) and found that the Golgi-targeting determinants of these glycosyltransferases were also composed of their cytosolic and transmembrane domains. To investigate whether the CTd of C2GnT could serve as a cis to medial Golgi-specific signal, we tested its ability to mislocalize two late-Golgi acting glycosyltransferases FucTI and FucTVII. We show that fusing the C2GnT-derived CTd with the catalytic domain of FucTVII resulted in a complete mislocalization of the enzyme to the C2GnT compartment, with a parallel alteration of sialyl-Lewis x synthesis and P-selectin binding. The intracellular distribution and activity of FucTI, however, were not affected. Thus, CTds of either early or late-Golgi acting glycosyltransferases represent the Golgi-targeting domains of these enzymes. In addition, we show that C2GnT-derived CTd can function as a cis/medial Golgi-targeting determinant.
- Published
- 2002
- Full Text
- View/download PDF
29. Engagement of T cell receptor triggers its recruitment to low-density detergent-insoluble membrane domains.
- Author
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Montixi C, Langlet C, Bernard AM, Thimonier J, Dubois C, Wurbel MA, Chauvin JP, Pierres M, and He HT
- Subjects
- Animals, Cell Compartmentation, Cetomacrogol, Detergents, Enzyme Inhibitors pharmacology, G(M1) Ganglioside analysis, Glycosylphosphatidylinositols analysis, Intracellular Membranes chemistry, Lymphocyte Specific Protein Tyrosine Kinase p56(lck) metabolism, Mice, Phosphoproteins metabolism, Phosphorylation, Protein-Tyrosine Kinases analysis, Solubility, Thymus Gland immunology, Tyrosine metabolism, ZAP-70 Protein-Tyrosine Kinase, src-Family Kinases antagonists & inhibitors, src-Family Kinases physiology, Intracellular Membranes metabolism, Receptor-CD3 Complex, Antigen, T-Cell analysis, Receptors, Antigen, T-Cell metabolism, Signal Transduction immunology
- Abstract
T-cell receptors (TCRs) upon binding to peptide-MHC ligands transduce signals in T lymphocytes. Tyrosine phosphorylations in the cytoplasmic domains of the CD3 (gammadeltaepsilon) and zeta subunits of the TCR complex by Src family kinases initiate the signaling cascades via docking and activation of ZAP-70 kinase and other signaling components. We examined the role of the low-density detergent-insoluble membranes (DIMs) in TCR signaling. Using mouse thymocytes as a model, we characterized the structural organization of DIMs in detail. We then demonstrated that TCR engagement triggered an immediate increase in the amount of TCR/CD3 present in DIMs, which directly involves the engaged receptor complexes. TCR/CD3 recruitment is accompanied by the accumulation of a series of prominent tyrosine-phosphorylated substrates and by an increase of the Lck activity in DIMs. Upon TCR stimulation, the DIM-associated receptor complexes are highly enriched in the hyperphosphorylated p23 zeta chains, contain most of the TCR/CD3-associated, phosphorylation-activated ZAP-70 kinases and seem to integrate into higher order, multiple tyrosine-phosphorylated substrate-containing protein complexes. The TCR/CD3 recruitment was found to depend on the activity of Src family kinases. We thus provide the first demonstration of recuitment of TCR/CD3 to DIMs upon receptor stimulation and propose it as a mechanism whereby TCR engagement is coupled to downstream signaling cascades.
- Published
- 1998
- Full Text
- View/download PDF
30. Immunocompetent cells requisite for graft rejection in Lineus (Invertebrata, Nemertea).
- Author
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Langlet C and Bierne J
- Subjects
- Animals, Immune System cytology, Immunity, Cellular, Phylogeny, Species Specificity, Transplantation, Homologous, Graft Rejection, Helminths immunology
- Abstract
Antecerebral ends from donors of one Lineus species (L. sanguineus) were grafted onto bispecific recipients previously constructed from two other Lineus species (denoted L. ruber----L. lacteus because the anterior component of chimeras was from L. ruber and the posterior component was from L. lacteus) and onto monospecific controls. Histological examination of areas where the tissues from L. sanguineus and L. ruber had been brought into contact by grafting always showed, at early stages, (6 to 20 days postgrafting), a great deal of difference depending upon whether the recipients were monospecific L. ruber or bispecific L. ruber----L. lacteus: only in grafts onto the former was there lysis of gland cells, connective tissue, muscular fibers, and finally epidermis. We attribute this lytic process to a strongly and rapidly cytotoxic action of lymphocyte-like cells from the L. ruber intestinal segment and the absence of lysis during the same stage in grafts onto composite recipients and monospecific L. lacteus to weak, delayed actions of immunocytes from the L. lacteus intestinal segment. Subsequent phagocytosis of material from lysed cell of grafts in the process of being rejected was effected by wandering amebocytes usually involved in destruction of degenerating "self" components, as in oosorption and resorptive processes after fasting. This work supports the existence of immunocytes at an early phylogenetic level.
- Published
- 1984
- Full Text
- View/download PDF
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