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Ozier-Lafontaine A, Fourneaux C, Durif G, Arsenteva P, Vallot C, Gandrillon O, Gonin-Giraud S, Michel B, Picard F. Kernel-based testing for single-cell differential analysis. Genome Biol 2024; 25:114. [PMID: 38702740 PMCID: PMC11069218 DOI: 10.1186/s13059-024-03255-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 04/22/2024] [Indexed: 05/06/2024] Open
Abstract
Single-cell technologies offer insights into molecular feature distributions, but comparing them poses challenges. We propose a kernel-testing framework for non-linear cell-wise distribution comparison, analyzing gene expression and epigenomic modifications. Our method allows feature-wise and global transcriptome/epigenome comparisons, revealing cell population heterogeneities. Using a classifier based on embedding variability, we identify transitions in cell states, overcoming limitations of traditional single-cell analysis. Applied to single-cell ChIP-Seq data, our approach identifies untreated breast cancer cells with an epigenomic profile resembling persister cells. This demonstrates the effectiveness of kernel testing in uncovering subtle population variations that might be missed by other methods.
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Affiliation(s)
- A Ozier-Lafontaine
- Nantes Université, Centrale Nantes, Laboratoire de Mathématiques Jean Leray, CNRS UMR 6629, F-44000, Nantes, France.
| | - C Fourneaux
- Laboratory of Biology and Modelling of the Cell, Université de Lyon, Ecole Normale Supérieure de Lyon, CNRS, UMR5239, Université Claude Bernard Lyon 1, Lyon, France
| | - G Durif
- Laboratory of Biology and Modelling of the Cell, Université de Lyon, Ecole Normale Supérieure de Lyon, CNRS, UMR5239, Université Claude Bernard Lyon 1, Lyon, France
| | - P Arsenteva
- Nantes Université, Centrale Nantes, Laboratoire de Mathématiques Jean Leray, CNRS UMR 6629, F-44000, Nantes, France
| | - C Vallot
- CNRS UMR3244, Institut Curie, PSL University, Paris, France
- Translational Research Department, Institut Curie, PSL University, Paris, France
| | - O Gandrillon
- Laboratory of Biology and Modelling of the Cell, Université de Lyon, Ecole Normale Supérieure de Lyon, CNRS, UMR5239, Université Claude Bernard Lyon 1, Lyon, France
| | - S Gonin-Giraud
- Laboratory of Biology and Modelling of the Cell, Université de Lyon, Ecole Normale Supérieure de Lyon, CNRS, UMR5239, Université Claude Bernard Lyon 1, Lyon, France
| | - B Michel
- Nantes Université, Centrale Nantes, Laboratoire de Mathématiques Jean Leray, CNRS UMR 6629, F-44000, Nantes, France.
| | - F Picard
- Laboratory of Biology and Modelling of the Cell, Université de Lyon, Ecole Normale Supérieure de Lyon, CNRS, UMR5239, Université Claude Bernard Lyon 1, Lyon, France.
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Martinez(†) M, Durand M, Jainsky L, Serre P, Vallot C, Jacquet L, Freyssenge J. État de connaissance des médecins urgentistes sur la prise en charge des intoxications au monoxyde de carbone en région Auvergne-Rhône-Alpes. Ann Fr Med Urgence 2022. [DOI: 10.3166/afmu-2022-0449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Objectif : L’intoxication au monoxyde de carbone (ICO) est un diagnostic souvent difficile en urgence. Son incidence restant faible, les médecins urgentistes (MU) y sont rarement confrontés mais la pertinence de leur prise en charge est essentielle pour limiter la morbi-mortalité. L’objectif principal de cette étude était d’évaluer le niveau de connaissance des MU sur la prise en charge des ICO dans une région française de 8,1 millions d’habitants. L’objectif secondaire était d’individualiser les facteurs associés à une bonne connaissance de la prise en charge en urgence de cette pathologie.
Matériel et méthodes : Étude descriptive multicentrique et déclarative, réalisée auprès de MU travaillant au sein de cette région à l’aide d’un questionnaire en ligne.
Résultat : 246 MU ont répondu à l’enquête, représentant 82 % des structures de médecine d’urgence de la région. Parmi eux, 27 % estimaient prendre en charge moins de deux ICO par an. Le protocole territorial était connu par 59 % des répondeurs. La médiane de réponses justes au questionnaire de connaissance était de 43 [40-47] sur 60. Un taux de réponses justes plus faible (< 70 %) était retrouvé sur les questions traitant du diagnostic (65 %) et des indications et contre-indications de l’oxygénothérapie hyperbare (61 %). Les facteurs associés à un meilleur taux de réponses justes étaient : la connaissance du protocole territorial (63 vs 46 %, p = 0,035), une ancienneté d’exercice ≥ 5 ans (60 vs 40 %, p = 0,014), une formation complémentaire à la médecine hyperbare (85 vs 53 %, p = 0,018), un nombre estimé de prise en charge d’ICO ≥ 2 (60 vs 43 %, p = 0,022) et une auto-évaluation de ses connaissances > 7/10 (68 vs 50 %, p = 0,007).
Conclusion : Cette étude a montré un niveau de connaissance perfectible des MU sur cette pathologie en rapport avec un faible nombre de prise en charge annuel. La création d’un consensus national est à encourager pour améliorer les pratiques.
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Papassin J, Favre-Wiki IM, Atroun T, Tahon F, Boubagra K, Rodier G, Bing F, Marcel S, Vallot C, Belle L, Hommel M, Detante O. Patient eligibility for thrombectomy after acute stroke: Northern French Alps database analysis. Rev Neurol (Paris) 2017; 173:216-221. [PMID: 28377089 DOI: 10.1016/j.neurol.2017.03.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2016] [Revised: 12/09/2016] [Accepted: 03/09/2017] [Indexed: 11/27/2022]
Abstract
BACKGROUND Since 2015, the emergence of mechanical thrombectomy as standard care in acute stroke has involved organizational changes not only for stroke centers, but also for entire emergency regional networks. The aim of our study was to assess the proportion of ischemic stroke patients, admitted to stroke units in the Northern French Alps within the first 6h of onset, eligible for thrombectomy. METHODS This study retrospectively analyzed the clinical and radiological data of all acute stroke patients hospitalized at three stroke units of the Northern French Alps Emergency Network (RENAU) in 2014. Eligible patients had proximal arterial occlusions of the anterior and posterior cerebral circulation, as confirmed by brain imaging, which could be treated by thrombectomy within 6h of symptom onset. RESULTS Of the 435 cases of acute ischemic stroke, 152 patients were treated by intravenous thrombolysis (IV rtPA). Of these patients, 83 (55%) had intracranial occlusions and were eligible for combined thrombectomy. Of the 283 patients not treatable by IV rtPA, 32 patients (11%) were eligible for primary thrombectomy. CONCLUSION Thrombectomy could be performed in 26% of our acute ischemic stroke patients (n=115/435), and a large increase in endovascular procedures is expected over the next few years that will require close collaboration among all partners in the emergency networks. Using our RENAU stroke database, it will be possible to compare various factors contributing to effective activity.
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Affiliation(s)
- J Papassin
- Department of neurology, stroke unit, CHU Grenoble-Alpes, 38043 Grenoble, France; RENAU network, centre hospitalier d'Annecy-Genevois, 74370 Epagny Metz-Tessy, France.
| | - I M Favre-Wiki
- Department of neurology, stroke unit, CHU Grenoble-Alpes, 38043 Grenoble, France; RENAU network, centre hospitalier d'Annecy-Genevois, 74370 Epagny Metz-Tessy, France
| | - T Atroun
- Department of neurology, stroke unit, CHU Grenoble-Alpes, 38043 Grenoble, France; RENAU network, centre hospitalier d'Annecy-Genevois, 74370 Epagny Metz-Tessy, France
| | - F Tahon
- Department of radiology, CHU Grenoble-Alpes, 38043 Grenoble, France; RENAU network, centre hospitalier d'Annecy-Genevois, 74370 Epagny Metz-Tessy, France
| | - K Boubagra
- Department of radiology, CHU Grenoble-Alpes, 38043 Grenoble, France; RENAU network, centre hospitalier d'Annecy-Genevois, 74370 Epagny Metz-Tessy, France
| | - G Rodier
- Department of neurology, Stroke Unit, centre hospitalier d'Annecy-Genevois, 74370 Epagny Metz-Tessy, France; RENAU network, centre hospitalier d'Annecy-Genevois, 74370 Epagny Metz-Tessy, France
| | - F Bing
- Department of radiology, centre hospitalier d'Annecy-Genevois, 74370 Epagny Metz-Tessy, France; RENAU network, centre hospitalier d'Annecy-Genevois, 74370 Epagny Metz-Tessy, France
| | - S Marcel
- Department of neurology, stroke unit, centre hospitalier Métropole Savoie, 73000 Chambéry, France; RENAU network, centre hospitalier d'Annecy-Genevois, 74370 Epagny Metz-Tessy, France
| | - C Vallot
- RENAU network, centre hospitalier d'Annecy-Genevois, 74370 Epagny Metz-Tessy, France
| | - L Belle
- RENAU network, centre hospitalier d'Annecy-Genevois, 74370 Epagny Metz-Tessy, France
| | - M Hommel
- Department of neurology, stroke unit, CHU Grenoble-Alpes, 38043 Grenoble, France; RENAU network, centre hospitalier d'Annecy-Genevois, 74370 Epagny Metz-Tessy, France; Université Grenoble-Alpes, 38400 Saint-Martin-d'Hères, France
| | - O Detante
- Department of neurology, stroke unit, CHU Grenoble-Alpes, 38043 Grenoble, France; RENAU network, centre hospitalier d'Annecy-Genevois, 74370 Epagny Metz-Tessy, France; Université Grenoble-Alpes, 38400 Saint-Martin-d'Hères, France
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Abstract
Abstract
Injection stretch blow molding (ISBM) is a two-step process that was designed and optimized mainly for unfilled PET resins. The present study focuses on stretch blow molding of a PET filled with different amounts of sub-micronic mineral fillers. The influence of fillers is analyzed thanks to DSC, DMA, tensile testing and processing in different configurations on a prototype apparatus and an industrial machine. It is demonstrated that fillers enhance crystallization kinetics, which leads to a reduction of the processing range. Differences in strain hardening induced by fillers make it necessary to adjust blowing temperature. However, the main effect occurs during the heating phase of the preforms. Temperature within a filled preform is much less homogeneous than in neat PET, making the temperature gradient totally different if the heating protocol is kept unchanged. Once the heating of filled preforms is controlled to reach equivalent temperature gradients, blowing is possible and rather equivalent to that of pure PET.
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Affiliation(s)
- N. Billon
- MINES ParisTech , Centre de Mise en Forme des Matériaux, Sophia Antipolis , France
| | - J.-M. Haudin
- MINES ParisTech , Centre de Mise en Forme des Matériaux, Sophia Antipolis , France
| | - C. Vallot
- MINES ParisTech , Centre de Mise en Forme des Matériaux, Sophia Antipolis , France
| | - C. Babin
- MINES ParisTech , Centre de Mise en Forme des Matériaux, Sophia Antipolis , France
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Vallot C, Hérault A, Boyle S, Bickmore WA, Radvanyi F. PRC2-independent chromatin compaction and transcriptional repression in cancer. Oncogene 2015; 34:741-51. [PMID: 24469045 DOI: 10.1038/onc.2013.604] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Revised: 12/10/2013] [Accepted: 12/20/2013] [Indexed: 12/13/2022]
Abstract
The silencing of large chromosomal regions by epigenetic mechanisms has been reported to occur frequently in cancer. Epigenetic marks, such as histone methylation and acetylation, are altered at these loci. However, the mechanisms of formation of such aberrant gene clusters remain largely unknown. Here, we show that, in cancer cells, the epigenetic remodeling of chromatin into hypoacetylated domains covered with histone H3K27 trimethylation is paralleled by changes in higher-order chromatin structures. Using fluorescence in situ hybridization, we demonstrate that regional epigenetic silencing corresponds to the establishment of compact chromatin domains. We show that gene repression is tightly correlated to the state of chromatin compaction and not to the levels of H3K27me3-its removal through the knockdown of EZH2 does not induce significant gene expression nor chromatin decompaction. Moreover, transcription can occur with intact high-H3K27me3 levels; treatment with histone deacetylase inhibitors can relieve chromatin compaction and gene repression, without altering H3K27me3 levels. Our findings imply that compaction and subsequent repression of large chromatin domains are not direct consequences of PRC2 deregulation in cancer cells. By challenging the role of EZH2 in aberrant gene silencing in cancer, these findings have therapeutical implications, notably for the choice of epigenetic drugs for tumors with multiple regional epigenetic alterations.
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Affiliation(s)
- C Vallot
- 1] CNRS, UMR 144 - Cell Biology Department, Institut Curie, Paris, France [2] Institut Curie, Centre de Recherche, Paris, France
| | - A Hérault
- 1] CNRS, UMR 144 - Cell Biology Department, Institut Curie, Paris, France [2] Institut Curie, Centre de Recherche, Paris, France
| | - S Boyle
- Chromosome and Gene Expression Section, MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine at the University of Edinburgh, Scotland, UK
| | - W A Bickmore
- 1] Chromosome and Gene Expression Section, MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine at the University of Edinburgh, Scotland, UK [2] Breakthrough Breast Cancer Research Unit, University of Edinburgh, Scotland, UK
| | - F Radvanyi
- 1] CNRS, UMR 144 - Cell Biology Department, Institut Curie, Paris, France [2] Institut Curie, Centre de Recherche, Paris, France
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Peuchant E, Carbonneau MA, Dubourg L, Thomas MJ, Perromat A, Vallot C, Clerc M. Lipoperoxidation in plasma and red blood cells of patients undergoing haemodialysis: vitamins A, E, and iron status. Free Radic Biol Med 1994; 16:339-46. [PMID: 8063197 DOI: 10.1016/0891-5849(94)90035-3] [Citation(s) in RCA: 111] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
In 14 patients undergoing haemodialysis, lipoperoxidation (LPO) processes were determined in plasma and red blood cells (RBC) before and after a dialysis session by determining (a) the direct substrate, polyunsaturated fatty acids (PUFA); (b) the end product of LPO, malondialdehyde (MDA); and (c) the hydrophobic antioxidant systems, vitamins A and E. In plasma before dialysis, linoleic and arachidonic acid, and the antioxidant vitamin E, were significantly lowered as compared to the healthy controls (p < 0.05). On the contrary, the free MDA level was enhanced (p < 0.05). These results were emphasized by a dialysis session. In RBC of these patients, no difference in linoleic acid, free MDA, or vitamin E level were observed before or after dialysis when compared to controls. However, only vitamin A was significantly higher in haemodialysis patients (before and after dialysis) and in renal failure patients (p < 0.05) than in the healthy control group. The present results suggest that increased RBC vitamin A may offer some degree of protection against oxidative stress in erythrocytes, but not in plasma where LPO is demonstrated.
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Affiliation(s)
- E Peuchant
- Laboratoire de Biochimie Médicale A, Université de Bordeaux II 146, France
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Fialon P, Leaute AG, Sassier P, Vallot C, Wone C. Use of red blood cell indices (MCV, MCH, RDW) in monitoring chronic hemodialysis patients treated with recombinant erythropoietin. Pathol Biol (Paris) 1993; 41:931-935. [PMID: 8159473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Human recombinant erythropoietin (rHu-Epo) is now extensively used in chronic renal failures; this treatment, resulting in a correction of the severe anemias seen in hemodialysed patients, may in turn lead to a resistance to rHu-Epo therapy by reason of the shortage of erythropoiesis factors, such as iron, vitamin B12 and folates. The utility of the red cell indices (MCV, MCH, RDW) for detection of early iron, folate and B12 deficiencies was studied in eighteen hemodialysed patients with end-stage renal failure treated with rHu-Epo; Microcytosis (MCV < 80 fl) was found ineffective in detecting iron deficiencies as well as macrocytosis (MCV > 100 fl) in folate and B12 deficiencies, partly due to the high incidence of associated iron and folate deficiencies. Lowered MCH (< 27 pg) was not more efficient than microcytosis in detecting early iron deficiencies. Increased RDW was the most sensitive feature for folate, iron and B12 deficiencies with respective sensitivities of 62.5%, 72% and 75%. The global specificity for detecting all deficiencies was 74%. However, high RDW values were not indicative of any type of deficiency; it may thus be concluded that RDW is a non expensive, non invasive and sensitive test, which allows a selection of hemodialysed patients treated with rHu-Epo for a complete investigation program, in order to detect early iron, B12 and folate deficiencies.
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Affiliation(s)
- P Fialon
- Laboratoire de Biologie, Hôpital Saint André, Bordeaux, France
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Peuchant E, Salles C, Vallot C, Wone C, Jensen R. Increase of erythrocyte resistance to hemolysis and modification of membrane lipids induced by hemodialysis. Clin Chim Acta 1988; 178:271-82. [PMID: 3240602 DOI: 10.1016/0009-8981(88)90235-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Mechanical fragility, deformability and lipid composition of erythrocyte membranes were studied in 22 uremic dialysed patients before and after dialysis in comparison to controls. While deformability was not affected by a dialysis session, osmotic and saponin resistances to hemolysis were significantly increased after dialysis (p less than 0.001). The lipid composition of erythrocyte membranes was also altered during dialysis, with a notable increase in cholesterol and a different phospholipid distribution, i.e. phosphatidylcholine and sphingomyelin significantly decreased (p less than 0.001). Likewise, the fatty acid distribution showed large variations with an increase in polyunsaturated fatty acid. The acute effect of dialysis on the membrane lipid composition seems to be linked to erythrocyte alterations. Its significance is discussed in relation to the asymmetric transverse distribution of phospholipids previously described in human erythrocyte.
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Affiliation(s)
- E Peuchant
- Laboratory of Biochemistry, Hôpital Saint-André, Bordeaux, France
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Ragnaud JM, Vallot C, Woné C. [A case of polycythemia in a patient with chronic renal insufficiency treated by continuous ambulatory peritoneal dialysis]. Presse Med 1984; 13:1458-9. [PMID: 6233599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
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