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Taper M, Carrington G, Peckham M, Lal S, Hume RD. A comparison of fixation and immunofluorescence protocols for successful reproducibility and improved signal in human left ventricle cardiac tissue. J Microsc 2024. [PMID: 38856969 DOI: 10.1111/jmi.13336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Revised: 04/14/2024] [Accepted: 05/17/2024] [Indexed: 06/11/2024]
Abstract
Immunohistochemistry (IHC) and immunofluorescence (IF) are crucial techniques for studying cardiac physiology and disease. The accuracy of these techniques is dependent on various aspects of sample preparation and processing. However, standardised protocols for sample preparation of tissues, particularly for fresh-frozen human left ventricle (LV) tissue, have yet to be established and could potentially lead to differences in staining and interpretation. Thus, this study aimed to optimise the reproducibility and quality of IF staining in fresh-frozen human LV tissue by systematically investigating crucial aspects of the sample preparation process. To achieve this, we subjected fresh-frozen human LV tissue to different fixation protocols, primary antibody incubation temperatures, antibody penetration reagents, and fluorescent probes. We found that neutral buffered formalin fixation reduced image artefacts and improved antibody specificity compared to both methanol and acetone fixation. Additionally, incubating primary antibodies at 37°C for 3 h improved fluorescence intensity compared to the commonly practised 4°C overnight incubation. Furthermore, we found that DeepLabel, an antibody penetration reagent, and smaller probes, such as fragmented antibodies and Affimers, improved the visualisation depth of cardiac structures. DeepLabel also improved antibody penetration in CUBIC cleared thick LV tissue fragments. Thus, our data underscores the importance of standardised protocols in IF staining and provides various means of improving staining quality. In addition to contributing to cardiac research by providing methodologies for IF, the findings and processes presented herein also establish a framework by which staining of other tissues may be optimised.
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Affiliation(s)
- Matthew Taper
- Faculty of Medicine and Health, School of Medical Sciences, The University of Sydney, Sydney, Australia
- Centre for Heart Failure and Diseases of the Aorta, The Baird Institute, Sydney, Australia
| | - Glenn Carrington
- Faculty of Biological Sciences, Astbury Centre for Structural Biology and the School of Molecular and Cellular Biology, University of Leeds, Leeds, UK
| | - Michelle Peckham
- Faculty of Biological Sciences, Astbury Centre for Structural Biology and the School of Molecular and Cellular Biology, University of Leeds, Leeds, UK
| | - Sean Lal
- Faculty of Medicine and Health, School of Medical Sciences, The University of Sydney, Sydney, Australia
- Centre for Heart Failure and Diseases of the Aorta, The Baird Institute, Sydney, Australia
- Department of Cardiology, Royal Prince Alfred Hospital, Sydney, Australia
| | - Robert D Hume
- Faculty of Medicine and Health, School of Medical Sciences, The University of Sydney, Sydney, Australia
- Centre for Heart Failure and Diseases of the Aorta, The Baird Institute, Sydney, Australia
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Qin Y, Jiang W, Li A, Gao M, Liu H, Gao Y, Tian X, Gong G. The Combination of Paraformaldehyde and Glutaraldehyde Is a Potential Fixative for Mitochondria. Biomolecules 2021; 11:711. [PMID: 34068806 PMCID: PMC8151741 DOI: 10.3390/biom11050711] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 04/30/2021] [Accepted: 05/07/2021] [Indexed: 01/31/2023] Open
Abstract
Mitochondria are highly dynamic organelles, constantly undergoing shape changes, which are controlled by mitochondrial movement, fusion, and fission. Mitochondria play a pivotal role in various cellular processes under physiological and pathological conditions, including metabolism, superoxide generation, calcium homeostasis, and apoptosis. Abnormal mitochondrial morphology and mitochondrial protein expression are always closely related to the health status of cells. Analysis of mitochondrial morphology and mitochondrial protein expression in situ is widely used to reflect the abnormality of cell function in the chemical fixed sample. Paraformaldehyde (PFA), the most commonly used fixative in cellular immunostaining, still has disadvantages, including loss of antigenicity and disruption of morphology during fixation. We tested the effect of ethanol (ETHO), PFA, and glutaraldehyde (GA) fixation on cellular mitochondria. The results showed that 3% PFA and 1.5% GA (PFA-GA) combination reserved mitochondrial morphology better than them alone in situ in cells. Mitochondrial network and protein antigenicity were well maintained, indicated by preserved MitoTracker and mitochondrial immunostaining after PFA-GA fixation. Our results suggest that the PFA-GA combination is a valuable fixative for the study of mitochondria in situ.
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Affiliation(s)
- Yuan Qin
- Institute for Regenerative Medicine, Shanghai East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai 200092, China; (Y.Q.); (W.J.); (A.L.); (M.G.); (H.L.); (Y.G.)
- Department of Pharmacy, Shanghai East Hospital, Tongji University, Shanghai 200120, China
| | - Wenting Jiang
- Institute for Regenerative Medicine, Shanghai East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai 200092, China; (Y.Q.); (W.J.); (A.L.); (M.G.); (H.L.); (Y.G.)
| | - Anqi Li
- Institute for Regenerative Medicine, Shanghai East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai 200092, China; (Y.Q.); (W.J.); (A.L.); (M.G.); (H.L.); (Y.G.)
| | - Meng Gao
- Institute for Regenerative Medicine, Shanghai East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai 200092, China; (Y.Q.); (W.J.); (A.L.); (M.G.); (H.L.); (Y.G.)
| | - Hanyu Liu
- Institute for Regenerative Medicine, Shanghai East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai 200092, China; (Y.Q.); (W.J.); (A.L.); (M.G.); (H.L.); (Y.G.)
| | - Yufei Gao
- Institute for Regenerative Medicine, Shanghai East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai 200092, China; (Y.Q.); (W.J.); (A.L.); (M.G.); (H.L.); (Y.G.)
| | - Xiangang Tian
- Department of Cardiovascular Surgery, Daping Hospital, Army Medical Center of PLA, Chongqing 400037, China;
| | - Guohua Gong
- Institute for Regenerative Medicine, Shanghai East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai 200092, China; (Y.Q.); (W.J.); (A.L.); (M.G.); (H.L.); (Y.G.)
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Oda SK, Anderson KG, Ravikumar P, Bonson P, Garcia NM, Jenkins CM, Zhuang S, Daman AW, Chiu EY, Bates BM, Greenberg PD. A Fas-4-1BB fusion protein converts a death to a pro-survival signal and enhances T cell therapy. J Exp Med 2020; 217:e20191166. [PMID: 32860705 PMCID: PMC7953733 DOI: 10.1084/jem.20191166] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 06/02/2020] [Accepted: 08/03/2020] [Indexed: 12/20/2022] Open
Abstract
Adoptive T cell therapy (ACT) with genetically modified T cells has shown impressive results against some hematologic cancers, but efficacy in solid tumors can be limited by restrictive tumor microenvironments (TMEs). For example, Fas ligand is commonly overexpressed in TMEs and induces apoptosis in tumor-infiltrating, Fas receptor-positive lymphocytes. We engineered immunomodulatory fusion proteins (IFPs) to enhance ACT efficacy, combining an inhibitory receptor ectodomain with a costimulatory endodomain to convert negative into positive signals. We developed a Fas-4-1BB IFP that replaces the Fas intracellular tail with costimulatory 4-1BB. Fas-4-1BB IFP-engineered murine T cells exhibited increased pro-survival signaling, proliferation, antitumor function, and altered metabolism in vitro. In vivo, Fas-4-1BB ACT eradicated leukemia and significantly improved survival in the aggressive KPC pancreatic cancer model. Fas-4-1BB IFP expression also enhanced primary human T cell function in vitro. Thus, Fas-4-1BB IFP expression is a novel strategy to improve multiple T cell functions and enhance ACT against solid tumors and hematologic malignancies.
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Affiliation(s)
- Shannon K. Oda
- Program in Immunology, Fred Hutchinson Cancer Research Center, Seattle, WA
| | | | - Pranali Ravikumar
- Program in Immunology, Fred Hutchinson Cancer Research Center, Seattle, WA
| | - Patrick Bonson
- Program in Immunology, Fred Hutchinson Cancer Research Center, Seattle, WA
| | - Nicolas M. Garcia
- Program in Immunology, Fred Hutchinson Cancer Research Center, Seattle, WA
| | - Cody M. Jenkins
- Program in Immunology, Fred Hutchinson Cancer Research Center, Seattle, WA
| | - Summer Zhuang
- Program in Immunology, Fred Hutchinson Cancer Research Center, Seattle, WA
| | - Andrew W. Daman
- Program in Immunology, Fred Hutchinson Cancer Research Center, Seattle, WA
| | - Edison Y. Chiu
- Program in Immunology, Fred Hutchinson Cancer Research Center, Seattle, WA
| | - Breanna M. Bates
- Program in Immunology, Fred Hutchinson Cancer Research Center, Seattle, WA
| | - Philip D. Greenberg
- Program in Immunology, Fred Hutchinson Cancer Research Center, Seattle, WA
- Department of Medicine/Oncology, University of Washington, Seattle, WA
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Misan A, Chan WY, Trott D, Hill PB. Survival ofStaphylococcus pseudintermediusin modified Romanowsky staining solutions. Vet Dermatol 2017; 28:333-e71. [DOI: 10.1111/vde.12435] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/20/2017] [Indexed: 12/01/2022]
Affiliation(s)
- Angus Misan
- School of Animal and Veterinary Sciences; University of Adelaide; Roseworthy South Australia 5371 Australia
| | - Wei Yee Chan
- School of Animal and Veterinary Sciences; University of Adelaide; Roseworthy South Australia 5371 Australia
| | - Darren Trott
- School of Animal and Veterinary Sciences; University of Adelaide; Roseworthy South Australia 5371 Australia
| | - Peter B. Hill
- School of Animal and Veterinary Sciences; University of Adelaide; Roseworthy South Australia 5371 Australia
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Martincuks A, Andryka K, Küster A, Schmitz-Van de Leur H, Komorowski M, Müller-Newen G. Nuclear translocation of STAT3 and NF-κB are independent of each other but NF-κB supports expression and activation of STAT3. Cell Signal 2017; 32:36-47. [PMID: 28089769 DOI: 10.1016/j.cellsig.2017.01.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 12/31/2016] [Accepted: 01/04/2017] [Indexed: 12/11/2022]
Abstract
NF-κB and STAT3 are essential transcription factors in immunity and act at the interface of the transition from chronic inflammation to cancer. Different functional crosstalks between NF-κB and STAT3 have been recently described arguing for a direct interaction of both proteins. During a systematic analysis of NF-κB/STAT3 crosstalk we observed that appearance of the subcellular distribution of NF-κB and STAT3 in immunofluorescence heavily depends on the fixation procedure. Therefore, we established an optimized fixation protocol for the reliable simultaneous analysis of the subcellular distributions of both transcription factors. Using this protocol we found that cytokine-induced nuclear accumulation of NF-κB or STAT3 did not alter the subcellular distribution of the other transcription factor. Both knockout and overexpression of STAT3 does not have any major effect on canonical TNFα-NF-κB signalling in MEF or HeLa cells. Similarly, knockout of p65 did not alter nuclear accumulation of STAT3 in response to IL-6. However, p65 expression correlates with elevated total cellular levels of STAT3 and STAT1 and supports activation of these transcription factors. Our findings in MEF cells argue against a direct physical interaction of free cellular NF-κB and STAT3 but point to more intricate functional interactions.
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Affiliation(s)
- Antons Martincuks
- Institute of Biochemistry and Molecular Biology, RWTH Aachen University, Pauwelsstraße 30, 52074 Aachen, Germany
| | - Katarzyna Andryka
- Systems Biology of Biochemical Signalling, Laboratory of Modelling in Biology and Medicine, Institute of Fundamental Technological Research, Polish Academy of Sciences, Pawinskiego 5b, 02-106 Warszawa, Poland
| | - Andrea Küster
- Institute of Biochemistry and Molecular Biology, RWTH Aachen University, Pauwelsstraße 30, 52074 Aachen, Germany
| | | | - Michal Komorowski
- Systems Biology of Biochemical Signalling, Laboratory of Modelling in Biology and Medicine, Institute of Fundamental Technological Research, Polish Academy of Sciences, Pawinskiego 5b, 02-106 Warszawa, Poland
| | - Gerhard Müller-Newen
- Institute of Biochemistry and Molecular Biology, RWTH Aachen University, Pauwelsstraße 30, 52074 Aachen, Germany.
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Chao Y, Zhang T. Optimization of fixation methods for observation of bacterial cell morphology and surface ultrastructures by atomic force microscopy. Appl Microbiol Biotechnol 2011; 92:381-92. [PMID: 21881891 PMCID: PMC3181414 DOI: 10.1007/s00253-011-3551-5] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2011] [Revised: 08/06/2011] [Accepted: 08/13/2011] [Indexed: 11/14/2022]
Abstract
Fixation ability of five common fixation solutions, including 2.5% glutaraldehyde, 10% formalin, 4% paraformaldehyde, methanol/acetone (1:1), and ethanol/acetic acid (3:1) were evaluated by using atomic force microscopy in the present study. Three model bacteria, i.e., Escherichia coli, Pseudomonas putida, and Bacillus subtilis were applied to observe the above fixation methods for the morphology preservation of bacterial cells and surface ultrastructures. All the fixation methods could effectively preserve cell morphology. However, for preserving bacterial surface ultrastructures, the methods applying aldehyde fixations performed much better than those using alcohols, since the alcohols could detach the surface filaments (i.e., flagella and pili) significantly. Based on the quantitative and qualitative assessments, the 2.5% glutaraldehyde was proposed as a promising fixation solution both for observing morphology of both bacterial cell and surface ultrastructures, while the methonal/acetone mixture was the worst fixation solution which may obtain unreliable results.
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Affiliation(s)
- Yuanqing Chao
- Environmental Biotechnology Laboratory, The University of Hong Kong, Pokfulam Road, Hong Kong, SAR, China
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Tissue fixation effects on immunohistochemical staining of caspase-3 in brain tissue. Appl Immunohistochem Mol Morphol 2008; 15:463-70. [PMID: 18091392 DOI: 10.1097/01.pai.0000213150.56687.78] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Fixation methods for tissue often vary amongst clinical and research laboratories. To evaluate the effects of fixation method on studies of brain tissue, we examined immunohistochemical outcomes amongst 2 fixatives, 4 caspase-3 antibodies, and 2 species (human infants and piglets). Fixatives were 10% neutral buffered formalin (NBF) or 10% NBF and glacial acetic acid (FAA). Antibodies for caspase-3 were commercially obtained and included 2 for active caspase-3, and 2 for procaspase-3 (CASP3 and CPP32). Immunohistochemical staining of caspase-3 varied with fixation method, with the greatest effect of fixation method observed for the active caspase-3 antibodies and this effect was present in both species. In NBF-fixed tissue, active caspase-3 immunoreactivity was only visible microscopically, and was specific to neuronal cell bodies. In FAA-fixed tissue, active caspase-3 immunoreactivity was visible macroscopically, and predominantly present in fiber tracts and fasciculi compared with neuronal bodies. Fixation and species differences were also identified for the procaspase-3 antibodies, CASP3 and CPP32, where FAA-fixed pig tissue showed abundant staining of blood vessels that were not observed in the NBF-fixed pig tissue or in the human tissue. This study characterizes differences in immunohistochemical outcomes using commercially available antibodies for caspase-3, according to tissue fixation method and species.
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Nunes-Correia I, Rodríguez JM, Eulálio A, Carvalho AL, Citovsky V, Simões S, Faro C, Salas ML, Pedroso de Lima MC. African swine fever virus p10 protein exhibits nuclear import capacity and accumulates in the nucleus during viral infection. Vet Microbiol 2007; 130:47-59. [PMID: 18243588 DOI: 10.1016/j.vetmic.2007.12.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2007] [Revised: 12/07/2007] [Accepted: 12/19/2007] [Indexed: 10/22/2022]
Abstract
African swine fever virus (ASFV), a large enveloped DNA-containing virus, infects domestic and wild pigs, and multiplies in soft ticks, causing an economically relevant hemorrhagic disease. Evaluation of the nuclear import ability of ASFV p10 protein was the major purpose of the present work. Two approaches were used to determine if p10 protein is imported into the nucleus by an active process: a yeast-based nuclear import assay and the determination of the subcellular localization of p10 protein in mammalian cells by fluorescence microscopy. The results obtained clearly demonstrate that p10 protein is actively imported into the nucleus, both in yeast and mammalian cells. Experiments aiming at identifying the critical residues responsible for the nuclear import of ASFV p10 protein indicate that the amino acids comprised between the positions 71 and 77 are important, although not sufficient, for the protein active nuclear import. In ASFV-infected cells, the p10 protein strongly accumulates in the nucleus at late times post-infection, indicating that p10 protein may accomplish an important function inside the nucleus during the late phase of the viral replication cycle.
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Affiliation(s)
- Isabel Nunes-Correia
- Centro de Neurociências e Biologia Celular, Universidade de Coimbra, 3004-517 Coimbra, Portugal
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Timmers M, Vekemans K, Vermijlen D, Asosingh K, Kuppen P, Bouwens L, Wisse E, Braet F. Interactions between rat colon carcinoma cells and Kupffer cells during the onset of hepatic metastasis. Int J Cancer 2004; 112:793-802. [PMID: 15386374 DOI: 10.1002/ijc.20481] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Liver sinusoids harbor populations of 2 important types of immunocompetent cells, Kupffer cells (KCs) and natural killer (NK) cells, which are thought to play an important role in controlling hepatic metastasis in the first 24 hr upon arrival of the tumor cells in the liver. We studied the early interaction of KCs, NK and CC531s colon carcinoma cells in a syngeneic rat model by confocal laser scanning microscopy. Results showed a minority of KCs (19% periportal and 7% pericentral) involved in the interaction with 94% of tumor cells and effecting the phagocytosis of 92% of them. NK cell depletion decreased the phagocytosis of tumor cells by KCs by 33% over a period of 24 hr, leaving 35% of the cancer cells free, as compared to 6% in NK-positive rats. Surviving cancer cells were primarily located close to the Glisson capsule, suggesting that metastasis would initiate from this region.
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Affiliation(s)
- Maarten Timmers
- Laboratory for Cell Biology and Histology, Free University of Brussels, Brussels, Belgium
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Vekemans K, Braet F, Muyllaert D, Wisse E. Nitric oxide from rat liver sinusoidal endothelial cells induces apoptosis in IFN gamma-sensitized CC531s colon carcinoma cells. J Hepatol 2004; 41:11-8. [PMID: 15246201 DOI: 10.1016/j.jhep.2004.03.026] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2003] [Revised: 03/15/2004] [Accepted: 03/31/2004] [Indexed: 12/20/2022]
Abstract
BACKGROUND/AIMS Investigation of apoptosis is pivotal in searching for mechanisms that eliminate colon cancer cells getting trapped in liver sinusoids at the time of surgical removal of the primary tumor. This study focuses on nitric oxide (NO), Fas/FasL and the involvement of interferon-gamma (IFNgamma) in liver sinusoidal endothelial cells (LSECs) and in the colon carcinoma cell line CC531s. METHODS Apoptosis was quantified and visualized in vitro by specific DNA fragmentation, specific staining and electron microscopy. In vivo experiments were also conducted. RESULTS In co-cultures of LSECs with CC531s, apoptosis of CC531s was observed only when they were pre-treated with IFNgamma, and was unaffected by blocking the Fas/FasL pathway. However, LSECs continuously produced NO, and apoptosis was inhibited by NO-inhibitors (NMMA and dexamethasone). When IFNgamma-sensitized CC531s were injected into rats, liver weight was lower, in contrast to control conditions where liver weight was higher. CONCLUSIONS (i) LSECs induce apoptosis in IFNgamma-sensitized CC531s in vitro; (ii) LSECs express FasL; (iii) Fas on CC531s becomes active after IFNgamma-treatment; however, (iv) blocking the Fas/FasL pathway had no effect; (v) apoptosis was inhibited by NO-inhibitors; (vi) the immune system uses this IFNgamma-activated pathway to support LSECs in killing tumor cells.
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Affiliation(s)
- Katrien Vekemans
- Laboratory for Cell Biology and Histology, Free University Brussels, Laarbeeklaan 103, B-1090 Brussels-Jette, Belgium.
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