25 results on '"Martin, O."'
Search Results
2. Mapping nanoscale carrier confinement in polycrystalline graphene by terahertz spectroscopy
- Author
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Whelan, Patrick R., De Fazio, Domenico, Pasternak, Iwona, Thomsen, Joachim D., Zelzer, Steffen, Mikkelsen, Martin O., Booth, Timothy J., Diekhöner, Lars, Sassi, Ugo, Johnstone, Duncan, Midgley, Paul A., Strupinski, Wlodek, Jepsen, Peter U., Ferrari, Andrea C., and Bøggild, Peter
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- 2024
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3. Mononuclear phagocyte sub-types in vitro display diverse transcriptional responses to dust mite exposure
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Leonie F. H. Fransen and Martin O. Leonard
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Mononuclear phagocytes ,Myeloid ,CD34 ,RNA-seq ,Diesel exhaust particles ,Dust mite ,Medicine ,Science - Abstract
Abstract Mononuclear phagocytes (MNP), including macrophages and dendritic cells form an essential component of primary responses to environmental hazards and toxic exposures. This is particularly important in disease conditions such as asthma and allergic airway disease, where many different cell types are present. In this study, we differentiated CD34+ haematopoietic stem cells towards different populations of MNP in an effort to understand how different cell subtypes present in inflammatory disease microenvironments respond to the common allergen house dust mite (HDM). Using single cell mRNA sequencing, we demonstrate that macrophage subtypes MCSPP1+ and MLCMARCO+ display different patterns of gene expression after HDM challenge, noted especially for the chemokines CXCL5, CXCL8, CCL5 and CCL15. MLCCD206Hi alternatively activated macrophages displayed the greatest changes in expression, while neutrophil and monocyte populations did not respond. Further work investigated how pollutant diesel exhaust particles could modify these transcriptional responses and revealed that CXC but not CC type chemokines were further upregulated. Through the use of diesel particles with adsorbed material removed, we suggest that soluble pollutants on these particles are the active constituents responsible for the modifying effects on HDM. This study highlights that environmental exposures may influence tissue responses dependent on which MNP cell type is present, and that these should be considerations when modelling such events in vitro. Understanding the nuanced responsiveness of different immune cell types to allergen and pollutant exposure also contributes to a better understanding of how these exposures influence the development and exacerbation of human disease.
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- 2024
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4. Mapping nanoscale carrier confinement in polycrystalline graphene by terahertz spectroscopy
- Author
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Patrick R. Whelan, Domenico De Fazio, Iwona Pasternak, Joachim D. Thomsen, Steffen Zelzer, Martin O. Mikkelsen, Timothy J. Booth, Lars Diekhöner, Ugo Sassi, Duncan Johnstone, Paul A. Midgley, Wlodek Strupinski, Peter U. Jepsen, Andrea C. Ferrari, and Peter Bøggild
- Subjects
Medicine ,Science - Abstract
Abstract Terahertz time-domain spectroscopy (THz-TDS) can be used to map spatial variations in electrical properties such as sheet conductivity, carrier density, and carrier mobility in graphene. Here, we consider wafer-scale graphene grown on germanium by chemical vapor deposition with non-uniformities and small domains due to reconstructions of the substrate during growth. The THz conductivity spectrum matches the predictions of the phenomenological Drude–Smith model for conductors with non-isotropic scattering caused by backscattering from boundaries and line defects. We compare the charge carrier mean free path determined by THz-TDS with the average defect distance assessed by Raman spectroscopy, and the grain boundary dimensions as determined by transmission electron microscopy. The results indicate that even small angle orientation variations below 5° within graphene grains influence the scattering behavior, consistent with significant backscattering contributions from grain boundaries.
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- 2024
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5. Induced pluripotent and CD34+ stem cell derived myeloid cells display differential responses to particle and dust mite exposure
- Author
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Leonie F. H. Fransen and Martin O. Leonard
- Subjects
Medicine ,Science - Abstract
Abstract Myeloid cells form an essential component of initial responses to environmental hazards and toxic exposures. The ability to model these responses in vitro is central to efforts tasked with identifying hazardous materials and understanding mechanisms of injury and disease. Induced pluripotent stem cell (iPSC) derived cells have been suggested as alternatives to more established primary cell testing systems for these purposes. iPSC derived macrophage and dendritic like cells were compared to CD34+ haematopoietic stem cell derived populations using transcriptomic analysis. Using single cell sequencing-based characterisation of iPSC derived myeloid cells, we identified transitional, mature and M2 like macrophages as well as dendritic like antigen presenting cells and fibrocytes. Direct transcriptomic comparisons between iPSC and CD34+ cell derived populations revealed higher expression of myeloid differentiation genes such as MNDA, CSF1R and CSF2RB in CD34+ cells, while iPSC populations had higher fibroblastic and proliferative markers. Exposure of differentiated macrophage populations to nanoparticle alone or in combination with dust mite, resulted in differential gene expression on combination only, with responses markedly absent in iPSC compared to CD34+ derived cells. The lack of responsiveness in iPSC derived cells may be attributable to lower levels of dust mite component receptors CD14, TLR4, CLEC7A and CD36. In summary, iPSC derived myeloid cells display typical characteristics of immune cells but may lack a fully mature phenotype to adequately respond to environmental exposures.
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- 2023
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6. Diagnostic features and management options for duodenal neuroendocrine neoplasms: a retrospective, multi-centre study
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Dalvinder Mandair, Lukasz Kamieniarz, Michail Pizanias, Martin O. Weickert, Akshay Narayan, Luke Furtado O’Mahony, Martyn Caplin, John Ramage, Andreas Prachalias, Rajaventhan Srirajaskanthan, and Christos Toumpanakis
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Medicine ,Science - Abstract
Abstract Duodenal neuroendocrine neoplasms (dNENs) are rare neoplasms but their incidence is on the rise. They are classified into 5 sub-types but there remains much heterogeneity in behaviour in particular of non-functioning dNENs. To retrospectively analyse outcomes for all types of dNENs, and highlight prognostic factors associated with worse outcome. 102 (57 m/45f.) patients were identified with mean age at diagnosis 62 (range 32–87) years. The majority were non-functioning tumours 87/102 and median size was 10 mm (range 0.9–130 mm). 83 patients had Stage I or II disease, of which 17 underwent endoscopic resection with R1 rate of 45% and complication rate 12%. 36 patients were kept under endoscopic surveillance. There were 11 deaths of which 4 were disease related. Age and Ki67 > 20% were associated with worse OS in all dNENs. In non-functioning dNENs Ki67 > 3% was a predictor of lymph nodes metastases with OR 18.2 (2.54–13) (p
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- 2022
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7. Diagnostic features and management options for duodenal neuroendocrine neoplasms: a retrospective, multi-centre study
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Mandair, Dalvinder, Kamieniarz, Lukasz, Pizanias, Michail, Weickert, Martin O., Narayan, Akshay, O’Mahony, Luke Furtado, Caplin, Martyn, Ramage, John, Prachalias, Andreas, Srirajaskanthan, Rajaventhan, and Toumpanakis, Christos
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- 2022
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8. Endoplasmic reticulum stress and the unfolded protein response in skeletal muscle of subjects suffering from peritoneal sepsis
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Metzing, Uta Barbara, von Loeffelholz, Christian, Steidl, Ricardo, Romeike, Bernd, Winkler, René, Rauchfuß, Falk, Settmacher, Utz, Stoppe, Christian, Coldewey, Sina M., Weinmann, Claudia, Weickert, Martin O., Claus, Ralf A., Birkenfeld, Andreas L., Kosan, Christian, and Horn, Paul
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- 2022
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9. Genomic profiling of the transcription factor Zfp148 and its impact on the p53 pathway
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Zou, Zhiyuan V., Gul, Nadia, Lindberg, Markus, Bokhari, Abdulmalik A., Eklund, Ella M., Garellick, Viktor, Patel, Angana A. H., Dzanan, Jozefina J., Titmuss, Ben O., Le Gal, Kristell, Johansson, Inger, Tivesten, Åsa, Forssell-Aronsson, Eva, Bergö, Martin O., Staffas, Anna, Larsson, Erik, Sayin, Volkan I., and Lindahl, Per
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- 2020
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10. Development of new genetic resources for faba bean (Vicia faba L.) breeding through the discovery of gene-based SNP markers and the construction of a high-density consensus map
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Carrillo-Perdomo, E., Vidal, A., Kreplak, J., Duborjal, H., Leveugle, M., Duarte, J., Desmetz, C., Deulvot, C., Raffiot, B., Marget, P., Tayeh, N., Pichon, J. P., Falque, M., Martin, O. C., Burstin, J., and Aubert, G.
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- 2020
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11. The MTH1 inhibitor TH588 is a microtubule-modulating agent that eliminates cancer cells by activating the mitotic surveillance pathway
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Gul, Nadia, Karlsson, Joakim, Tängemo, Carolina, Linsefors, Sanna, Tuyizere, Samuel, Perkins, Rosie, Ala, Chandu, Zou, Zhiyuan, Larsson, Erik, Bergö, Martin O., and Lindahl, Per
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- 2019
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12. Induced pluripotent and CD34+ stem cell derived myeloid cells display differential responses to particle and dust mite exposure.
- Author
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Fransen, Leonie F. H. and Leonard, Martin O.
- Subjects
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INDUCED pluripotent stem cells , *MYELOID cells , *DUST , *ANTIGEN presenting cells , *HEMATOPOIETIC stem cells - Abstract
Myeloid cells form an essential component of initial responses to environmental hazards and toxic exposures. The ability to model these responses in vitro is central to efforts tasked with identifying hazardous materials and understanding mechanisms of injury and disease. Induced pluripotent stem cell (iPSC) derived cells have been suggested as alternatives to more established primary cell testing systems for these purposes. iPSC derived macrophage and dendritic like cells were compared to CD34+ haematopoietic stem cell derived populations using transcriptomic analysis. Using single cell sequencing-based characterisation of iPSC derived myeloid cells, we identified transitional, mature and M2 like macrophages as well as dendritic like antigen presenting cells and fibrocytes. Direct transcriptomic comparisons between iPSC and CD34+ cell derived populations revealed higher expression of myeloid differentiation genes such as MNDA, CSF1R and CSF2RB in CD34+ cells, while iPSC populations had higher fibroblastic and proliferative markers. Exposure of differentiated macrophage populations to nanoparticle alone or in combination with dust mite, resulted in differential gene expression on combination only, with responses markedly absent in iPSC compared to CD34+ derived cells. The lack of responsiveness in iPSC derived cells may be attributable to lower levels of dust mite component receptors CD14, TLR4, CLEC7A and CD36. In summary, iPSC derived myeloid cells display typical characteristics of immune cells but may lack a fully mature phenotype to adequately respond to environmental exposures. [ABSTRACT FROM AUTHOR]
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- 2023
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13. Multi-Method Molecular Characterisation of Human Dust-Mite-associated Allergic Asthma
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Daniel P Tonge, Emma Whittle, Martin O. Leonard, and Timothy W. Gant
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0301 basic medicine ,Adult ,Male ,Allergy ,Population ,lcsh:Medicine ,Article ,03 medical and health sciences ,RC705 ,0302 clinical medicine ,Immune system ,Gene expression analysis ,Gene expression ,medicine ,Hypersensitivity ,Animals ,Humans ,Microbiome ,RNA, Messenger ,education ,Transcriptomics ,lcsh:Science ,Asthma ,House dust mite ,education.field_of_study ,Multidisciplinary ,biology ,Pyroglyphidae ,lcsh:R ,Case-control study ,Allergens ,Immunoglobulin E ,Middle Aged ,biology.organism_classification ,medicine.disease ,030104 developmental biology ,Case-Control Studies ,Immunology ,Biomarker (medicine) ,Tumor necrosis factor alpha ,Female ,lcsh:Q ,030217 neurology & neurosurgery - Abstract
Asthma is a chronic inflammatory disorder of the airways. Disease presentation varies greatly in terms of cause, development, severity, and response to medication, and thus the condition has been subdivided into a number of asthma phenotypes. There is still an unmet need for the identification of phenotype-specific markers and accompanying molecular tools that facilitate the classification of asthma phenotype. To this end, we utilised a range of molecular tools to characterise a well-defined group of female adults with poorly controlled atopic asthma associated with house dust mite (HDM) allergy, relative to non-asthmatic control subjects. Circulating messenger RNA (mRNA) and microRNA (miRNA) were sequenced and quantified, and a differential expression analysis of the two RNA populations performed to determine how gene expression and regulation varied in the disease state. Further, a number of circulating proteins (IL-4, 5, 10, 13, 17 A, Eotaxin, GM-CSF, IFNy, MCP-1, TARC, TNFα, Total IgE, and Endotoxin) were quantified to determine whether the protein profiles differed significantly dependent on disease state. Finally, we utilised a previously published assessment of the circulating “blood microbiome” performed using 16S rRNA amplification and sequencing. Asthmatic subjects displayed a range of significant alterations to circulating gene expression and regulation, relative to healthy control subjects, that may influence systemic immune activity. Notably, several circulating mRNAs were detected in just the asthma group or just in the control group, and many more were observed to be expressed at significantly different levels in the asthma group compared to the control group. Proteomic analysis revealed increased levels of inflammatory proteins within the serum, and decreased levels of the bacterial endotoxin protein in the asthmatic state. Comparison of blood microbiome composition revealed a significant increase in the Firmicutes phylum with asthma that was associated with a concomitant reduction in the Proteobacteria phylum. This study provides a valuable insight into the systemic changes evident in the HDM-associated asthma, identifies a range of molecules that are present in the circulation in a condition-specific manner (with clear biomarker potential), and highlights a range of hypotheses for further study.
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- 2019
14. Genomic profiling of the transcription factor Zfp148 and its impact on the p53 pathway
- Author
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Ella M. Eklund, Jozefina J. Dzanan, Markus Lindberg, Anna Staffas, Ben O. Titmuss, Angana A. H. Patel, Erik Larsson, Per Lindahl, Zhiyuan V. Zou, Eva Forssell-Aronsson, Kristell Le Gal, Inger Johansson, Nadia Gul, Åsa Tivesten, Abdulmalik A. Bokhari, Volkan I. Sayin, Viktor Garellick, and Martin O. Bergo
- Subjects
0301 basic medicine ,Chromatin Immunoprecipitation ,Cell division ,lcsh:Medicine ,Down-Regulation ,Cell Cycle Proteins ,Biology ,Senescence ,Article ,Cell Line ,03 medical and health sciences ,Mice ,0302 clinical medicine ,Transcription (biology) ,RNA interference ,Animals ,RNA, Small Interfering ,lcsh:Science ,Transcription factor ,Cyclin-Dependent Kinase Inhibitor p16 ,Etoposide ,Multidisciplinary ,Cell growth ,Activator (genetics) ,lcsh:R ,Promoter ,Cell Cycle Checkpoints ,Fibroblasts ,Cell Cycle Gene ,Cell biology ,E2F Transcription Factors ,Computational biology and bioinformatics ,DNA-Binding Proteins ,030104 developmental biology ,Gene Ontology ,Gene Expression Regulation ,lcsh:Q ,RNA Interference ,CRISPR-Cas Systems ,Cisplatin ,Tumor Suppressor Protein p53 ,Chromatin immunoprecipitation ,030217 neurology & neurosurgery ,DNA Damage ,Signal Transduction ,Transcription Factors - Abstract
Recent data suggest that the transcription factor Zfp148 represses activation of the tumor suppressor p53 in mice and that therapeutic targeting of the human orthologue ZNF148 could activate the p53 pathway without causing detrimental side effects. We have previously shown that Zfp148 deficiency promotes p53-dependent proliferation arrest of mouse embryonic fibroblasts (MEFs), but the underlying mechanism is not clear. Here, we showed that Zfp148 deficiency downregulated cell cycle genes in MEFs in a p53-dependent manner. Proliferation arrest of Zfp148-deficient cells required increased expression of ARF, a potent activator of the p53 pathway. Chromatin immunoprecipitation showed that Zfp148 bound to the ARF promoter, suggesting that Zfp148 represses ARF transcription. However, Zfp148 preferentially bound to promoters of other transcription factors, indicating that deletion of Zfp148 may have pleiotropic effects that activate ARF and p53 indirectly. In line with this, we found no evidence of genetic interaction between TP53 and ZNF148 in CRISPR and siRNA screen data from hundreds of human cancer cell lines. We conclude that Zfp148 deficiency, by increasing ARF transcription, downregulates cell cycle genes and cell proliferation in a p53-dependent manner. However, the lack of genetic interaction between ZNF148 and TP53 in human cancer cells suggests that therapeutic targeting of ZNF148 may not increase p53 activity in humans.
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- 2019
15. Detecting human melanoma cell re-differentiation following BRAF or heat shock protein 90 inhibition using photoacoustic and magnetic resonance imaging
- Author
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Anant, Shah, Teresa, Delgado-Goni, Teresa, Casals Galobart, Slawomir, Wantuch, Yann, Jamin, Martin O, Leach, Simon P, Robinson, Jeffrey, Bamber, and Mounia, Beloueche-Babari
- Subjects
Proto-Oncogene Proteins B-raf ,Science ,Antineoplastic Agents ,Cell Differentiation ,Pigments, Biological ,Magnetic Resonance Imaging ,Article ,Photoacoustic Techniques ,Cell Line, Tumor ,Humans ,Medicine ,HSP90 Heat-Shock Proteins ,Melanoma ,Protein Kinase Inhibitors ,neoplasms ,Cell Proliferation - Abstract
Targeted therapies specific to the BRAF-MEK-ERK signaling pathway have shown great promise in the treatment of malignant melanoma in the last few years, with these drugs now commonly used in clinic. Melanoma cells treated using these agents are known to exhibit increased levels of melanin pigment and tyrosinase activity. In this study we assessed the potential of non-invasive imaging approaches (photoacoustic imaging (PAI) and magnetic resonance imaging (MRI)) to detect melanin induction in SKMEL28 human melanoma cells, following inhibition of Hsp90 and BRAF signaling using 17-AAG and vemurafenib, respectively. We confirmed, using western blot and spectrophotometry, that Hsp90 or BRAF inhibitor-induced melanoma cell differentiation resulted in an upregulation of tyrosinase and melanin expression levels, in comparison to control cells. This post-treatment increase in cellular pigmentation induced a significant increase in PAI signals that are spectrally identifiable and shortening of the MRI relaxation times T 1 and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${{\boldsymbol{T}}}_{{\bf{2}}}^{{\boldsymbol{\ast }}}$$\end{document}T2∗. This proof-of-concept study demonstrates the potential of MRI and PAI for detecting the downstream cellular changes induced by Hsp90 and BRAF-MEK-targeted therapies in melanoma cells with potential significance for in vivo imaging.
- Published
- 2017
16. The MTH1 inhibitor TH588 is a microtubule-modulating agent that eliminates cancer cells by activating the mitotic surveillance pathway
- Author
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Nadia Gul, Carolina Tängemo, Chandu Ala, Martin O. Bergo, Rosie Perkins, Sanna Linsefors, Per Lindahl, Samuel Tuyizere, Erik Larsson, Joakim Karlsson, and Zhiyuan Zou
- Subjects
lcsh:Medicine ,Mitosis ,Antineoplastic Agents ,Spindle Apparatus ,Biology ,Microtubules ,Article ,Target validation ,03 medical and health sciences ,Targeted therapies ,0302 clinical medicine ,Live cell imaging ,Microtubule ,Cell Line, Tumor ,medicine ,Humans ,Cytotoxic T cell ,lcsh:Science ,030304 developmental biology ,0303 health sciences ,Multidisciplinary ,lcsh:R ,Cell Cycle ,G1 Phase ,Cancer ,Cell cycle ,medicine.disease ,Phosphoric Monoester Hydrolases ,Tubulin Modulators ,3. Good health ,Cell biology ,Spindle apparatus ,Gene Expression Regulation, Neoplastic ,DNA Repair Enzymes ,Pyrimidines ,030220 oncology & carcinogenesis ,Cancer cell ,Carcinoma, Large Cell ,lcsh:Q ,CRISPR-Cas Systems ,Tumor Suppressor Protein p53 ,Ubiquitin Thiolesterase - Abstract
The mut-T homolog-1 (MTH1) inhibitor TH588 has shown promise in preclinical cancer studies but its targeting specificity has been questioned. Alternative mechanisms for the anti-cancer effects of TH588 have been suggested but the question remains unresolved. Here, we performed an unbiased CRISPR screen on human lung cancer cells to identify potential mechanisms behind the cytotoxic effect of TH588. The screen identified pathways and complexes involved in mitotic spindle regulation. Using immunofluorescence and live cell imaging, we showed that TH588 rapidly reduced microtubule plus-end mobility, disrupted mitotic spindles, and prolonged mitosis in a concentration-dependent but MTH1-independent manner. These effects activated a USP28-p53 pathway – the mitotic surveillance pathway – that blocked cell cycle reentry after prolonged mitosis; USP28 acted upstream of p53 to arrest TH588-treated cells in the G1-phase of the cell cycle. We conclude that TH588 is a microtubule-modulating agent that activates the mitotic surveillance pathway and thus prevents cancer cells from re-entering the cell cycle.
- Published
- 2019
17. Finite Dimension: A Mathematical Tool to Analise Glycans
- Author
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Alonso, J. M., primary, Arroyuelo, A., additional, Garay, P. G., additional, Martin, O. A., additional, and Vila, J. A., additional
- Published
- 2018
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18. Recombinant Reg3β protein protects against streptozotocin-induced β-cell damage and diabetes
- Author
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Xiang Li, Martin O. Alfred, Min Wang, Lu-Ting Yu, Zhiyuan Zhang, Meng-Qi Yang, Chen Luo, and Jun-Li Liu
- Subjects
Male ,0301 basic medicine ,medicine.medical_specialty ,endocrine system diseases ,Cell Survival ,medicine.medical_treatment ,Pancreatitis-Associated Proteins ,Acinar Cells ,Protective Agents ,Article ,Cell Line ,Diabetes Mellitus, Experimental ,Mice ,03 medical and health sciences ,Insulin-Secreting Cells ,Internal medicine ,medicine ,Animals ,Insulin ,Cell damage ,Protein kinase B ,Mice, Inbred BALB C ,geography ,Multidisciplinary ,geography.geographical_feature_category ,Chemistry ,Cell growth ,Cell Cycle ,Cell cycle ,Islet ,medicine.disease ,Streptozotocin ,Pancreas, Exocrine ,Recombinant Proteins ,030104 developmental biology ,medicine.anatomical_structure ,Endocrinology ,Proto-Oncogene Proteins c-bcl-2 ,Glucagon-Secreting Cells ,Pancreas ,medicine.drug - Abstract
Regenerating genes (Reg) have been found during the search for factors involved in pancreatic islet regeneration. Our recent study discovered that pancreatic β-cell-specific overexpression of Reg3β protects against streptozotocin (Stz) -induced diabetes in mice. To investigate its potential roles in the treatment of diabetes, we produced a recombinant Reg3β protein and provided evidence that it is active in promoting islet β-cell survival against Stz- triggered cell death. Though ineffective in alleviating preexisting diabetes, pretreatment of recombinant Reg3β was capable of minimizing the Stz-induced hyperglycemia and weight loss, by preserving serum and pancreatic insulin levels, and islet β-cell mass. No obvious changes were observed in the rate of cell proliferation and hypertrophy in α- or acinar-cells after treatment with recombinant Reg3β. The underlying mechanism of Reg3β-mediated protection seems to involve Akt activation which upregulates Bcl-2 and Bcl-xL levels and consequently promotes cell survival.
- Published
- 2016
19. Detecting human melanoma cell re-differentiation following BRAF or heat shock protein 90 inhibition using photoacoustic and magnetic resonance imaging
- Author
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Shah, Anant, primary, Delgado-Goni, Teresa, additional, Casals Galobart, Teresa, additional, Wantuch, Slawomir, additional, Jamin, Yann, additional, Leach, Martin O., additional, Robinson, Simon P., additional, Bamber, Jeffrey, additional, and Beloueche-Babari, Mounia, additional
- Published
- 2017
- Full Text
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20. Characterization of a Setup to test the Impact of High-Amplitude Pressure Waves on Living Cells
- Author
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Johanna Wessolleck, Ulf Dietrich Kahlert, Mischa Schmidt, Jens Osterholz, Martin O. Steinhauser, Jaroslaw Maciaczyk, Donata Maciaczyk, Guido Nikkhah, Benjamin Merkt, and Publica
- Subjects
Length scale ,Pathology ,medicine.medical_specialty ,Photon ,Computer science ,Article ,law.invention ,law ,Laser-Doppler Flowmetry ,Pressure ,Tumor Cells, Cultured ,medicine ,Humans ,Computer Simulation ,Photons ,Pressure wave ,Multidisciplinary ,High amplitude ,Brain Neoplasms ,Lasers ,Mechanics ,Laser Doppler velocimetry ,Laser ,Photon Doppler velocimetry ,Characterization (materials science) ,Glioblastoma - Abstract
The impact of pressure waves on cells may provide several possible applications in biology and medicine including the direct killing of tumors, drug delivery or gene transfection. In this study we characterize the physical properties of mechanical pressure waves generated by a nanosecond laser pulse in a setup with well-defined cell culture conditions. To systematically characterize the system on the relevant length and time scales (micrometers and nanoseconds) we use photon Doppler velocimetry (PDV) and obtain velocity profiles of the cell culture vessel at the passage of the pressure wave. These profiles serve as input for numerical pressure wave simulations that help to further quantify the pressure conditions on the cellular length scale. On the biological level we demonstrate killing of glioblastoma cells and quantify experimentally the pressure threshold for cell destruction.
- Published
- 2014
21. Recombinant Reg3β protein protects against streptozotocin-induced β-cell damage and diabetes
- Author
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Luo, Chen, primary, Yu, Lu-Ting, additional, Yang, Meng-Qi, additional, Li, Xiang, additional, Zhang, Zhi-Yuan, additional, Alfred, Martin O, additional, Liu, Jun-Li, additional, and Wang, Min, additional
- Published
- 2016
- Full Text
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22. Characterization of a Setup to test the Impact of High-Amplitude Pressure Waves on Living Cells
- Author
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Schmidt, Mischa, primary, Kahlert, Ulf, additional, Wessolleck, Johanna, additional, Maciaczyk, Donata, additional, Merkt, Benjamin, additional, Maciaczyk, Jaroslaw, additional, Osterholz, Jens, additional, Nikkhah, Guido, additional, and Steinhauser, Martin O., additional
- Published
- 2014
- Full Text
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23. Endoplasmic reticulum stress and the unfolded protein response in skeletal muscle of subjects suffering from peritoneal sepsis
- Author
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Uta Barbara Metzing, Christian von Loeffelholz, Ricardo Steidl, Bernd Romeike, René Winkler, Falk Rauchfuß, Utz Settmacher, Christian Stoppe, Sina M. Coldewey, Claudia Weinmann, Martin O. Weickert, Ralf A. Claus, Andreas L. Birkenfeld, Christian Kosan, and Paul Horn
- Subjects
Medicine ,Science - Abstract
Abstract We provide a descriptive characterization of the unfolded protein response (UPR) in skeletal muscle of human patients with peritoneal sepsis and a sepsis model of C57BL/6J mice. Patients undergoing open surgery were included in a cross-sectional study and blood and skeletal muscle samples were taken. Key markers of the UPR and cluster of differentiation 68 (CD68) as surrogate of inflammatory injury were evaluated by real-time PCR and histochemical staining. CD68 mRNA increased with sepsis in skeletal muscle of patients and animals (p
- Published
- 2022
- Full Text
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24. Embracing firefly flash pattern variability with data-driven species classification.
- Author
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Martin O, Nguyen C, Sarfati R, Chowdhury M, Iuzzolino ML, Nguyen DMT, Layer RM, and Peleg O
- Subjects
- Humans, Animals, Fireflies, Sexual Behavior, Animal
- Abstract
Many nocturnally active fireflies use precisely timed bioluminescent patterns to identify mates, making them especially vulnerable to light pollution. As urbanization continues to brighten the night sky, firefly populations are under constant stress, and close to half of the species are now threatened. Ensuring the survival of firefly biodiversity depends on a large-scale conservation effort to monitor and protect thousands of populations. While species can be identified by their flash patterns, current methods require expert measurement and manual classification and are infeasible given the number and geographic distribution of fireflies. Here we present the application of a recurrent neural network (RNN) for accurate automated firefly flash pattern classification. Using recordings from commodity cameras, we can extract flash trajectories of individuals within a swarm and classify their species with an accuracy of approximately seventy percent. In addition to its potential in population monitoring, automated classification provides the means to study firefly behavior at the population level. We employ the classifier to measure and characterize the variability within and between swarms, unlocking a new dimension of their behavior. Our method is open source, and deployment in community science applications could revolutionize our ability to monitor and understand firefly populations., (© 2024. The Author(s).)
- Published
- 2024
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25. Siland a R package for estimating the spatial influence of landscape.
- Author
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Carpentier F and Martin O
- Abstract
The spatial distributions of populations are both influenced by local variables and by characteristics of surrounding landscapes. Understanding how landscape features spatially structure the frequency of a trait in a population, the abundance of a species or the species' richness remains difficult specially because the spatial scale effects of the landscape variables are unknown. Various methods have been proposed but their results are not easily comparable. Here, we introduce "siland", a general method for analyzing the effect of landscape features. Based on a sequential procedure of maximum likelihood estimation, it simultaneously estimates the spatial scales and intensities of landscape variable effects. It does not require any information about the scale of effect. It integrates two landscape effects models: one is based on focal sample site (Bsiland, b for buffer) and one is distance weighted using Spatial Influence Function (Fsiland, f for function). We implemented "siland" in the adaptable and user-friendly R eponym package. It performs landscape analysis on georeferenced point observations (described in a Geographic Information System shapefile format) and allows for effects tests, effects maps and models comparison. We illustrated its use on a real dataset by the study of a crop pest (codling moth densities).
- Published
- 2021
- Full Text
- View/download PDF
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