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Ma C, Liu L, Li YJ, Chen LG, Pan CS, Zhang Y, Wang H, Chen SY, Lu JP. Intravoxel incoherent motion MRI of the healthy pancreas: Monoexponential and biexponential apparent diffusion parameters of the normal head, body and tail. J Magn Reson Imaging 2014; 41:1236-41. [PMID: 24979657 DOI: 10.1002/jmri.24684] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Accepted: 06/10/2014] [Indexed: 02/01/2023] Open
Affiliation(s)
- Chao Ma
- Department of Radiology; Changhai Hospital of Shanghai, The Second Military Medical University; Shanghai China
| | - Li Liu
- Department of Radiology; Changhai Hospital of Shanghai, The Second Military Medical University; Shanghai China
| | - Yan-jun Li
- Department of Radiology; Changhai Hospital of Shanghai, The Second Military Medical University; Shanghai China
- Department of Medical Imaging; Jinling Hospital, Clinical School of Medical College, Nanjing University; Nanjing China
| | - Lu-guang Chen
- Department of Radiology; Changhai Hospital of Shanghai, The Second Military Medical University; Shanghai China
| | - Chun-shu Pan
- Department of Radiology; Changhai Hospital of Shanghai, The Second Military Medical University; Shanghai China
| | | | - He Wang
- GE Healthcare, MR Group; Shanghai China
| | - Shi-yue Chen
- Department of Radiology; Changhai Hospital of Shanghai, The Second Military Medical University; Shanghai China
| | - Jian-ping Lu
- Department of Radiology; Changhai Hospital of Shanghai, The Second Military Medical University; Shanghai China
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52
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Destruction of tissue, cells and organelles in type 1 diabetic rats presented at macromolecular resolution. Sci Rep 2014; 3:1804. [PMID: 23652855 PMCID: PMC3647201 DOI: 10.1038/srep01804] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Accepted: 04/19/2013] [Indexed: 01/15/2023] Open
Abstract
Finding alternatives for insulin therapy and making advances in etiology of type 1 diabetes benefits from a full structural and functional insight into Islets of Langerhans. Electron microscopy (EM) can visualize Islet morphology at the highest possible resolution, however, conventional EM only provides biased snapshots and lacks context. We developed and employed large scale EM and compiled a resource of complete cross sections of rat Islets during immuno-destruction to provide unbiased structural insight of thousands of cells at macromolecular resolution. The resource includes six datasets, totalling 25.000 micrographs, annotated for cellular and ultrastructural changes during autoimmune diabetes. Granulocytes are attracted to the endocrine tissue, followed by extravasation of a pleiotrophy of leukocytes. Subcellullar changes in beta cells include endoplasmic reticulum stress, insulin degranulation and glycogen accumulation. Rare findings include erythrocyte extravasation and nuclear actin-like fibers. While we focus on a rat model of autoimmune diabetes, our approach is general applicable.
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53
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Zhou Y, Waanders LF, Holmseth S, Guo C, Berger UV, Li Y, Lehre AC, Lehre KP, Danbolt NC. Proteome analysis and conditional deletion of the EAAT2 glutamate transporter provide evidence against a role of EAAT2 in pancreatic insulin secretion in mice. J Biol Chem 2013; 289:1329-44. [PMID: 24280215 DOI: 10.1074/jbc.m113.529065] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Islet function is incompletely understood in part because key steps in glutamate handling remain undetermined. The glutamate (excitatory amino acid) transporter 2 (EAAT2; Slc1a2) has been hypothesized to (a) provide islet cells with glutamate, (b) protect islet cells against high extracellular glutamate concentrations, (c) mediate glutamate release, or (d) control the pH inside insulin secretory granules. Here we floxed the EAAT2 gene to produce the first conditional EAAT2 knock-out mice. Crossing with Nestin-cyclization recombinase (Cre) eliminated EAAT2 from the brain, resulting in epilepsy and premature death, confirming the importance of EAAT2 for brain function and validating the genetic construction. Crossing with insulin-Cre lines (RIP-Cre and IPF1-Cre) to obtain pancreas-selective deletion did not appear to affect survival, growth, glucose tolerance, or β-cell number. We found (using TaqMan RT-PCR, immunoblotting, immunocytochemistry, and proteome analysis) that the EAAT2 levels were too low to support any of the four hypothesized functions. The proteome analysis detected more than 7,000 islet proteins of which more than 100 were transporters. Although mitochondrial glutamate transporters and transporters for neutral amino acids were present at high levels, all other transporters with known ability to transport glutamate were strikingly absent. Glutamate-metabolizing enzymes were abundant. The level of glutamine synthetase was 2 orders of magnitude higher than that of glutaminase. Taken together this suggests that the uptake of glutamate by islets from the extracellular fluid is insignificant and that glutamate is intracellularly produced. Glutamine synthetase may be more important for islets than assumed previously.
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Affiliation(s)
- Yun Zhou
- From The Neurotransporter Group, Department of Anatomy, Institute of Basic Medical Sciences, University of Oslo, 0317 Oslo, Norway
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54
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Revascularization of transplanted pancreatic islets and role of the transplantation site. Clin Dev Immunol 2013; 2013:352315. [PMID: 24106517 PMCID: PMC3782812 DOI: 10.1155/2013/352315] [Citation(s) in RCA: 105] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Accepted: 08/09/2013] [Indexed: 12/16/2022]
Abstract
Since the initial reporting of the successful reversal of hyperglycemia through the transplantation of pancreatic islets, significant research efforts have been conducted in elucidating the process of revascularization and the influence of engraftment site on graft function and survival. During the isolation process the intrinsic islet vascular networks are destroyed, leading to impaired revascularization after transplant. As a result, in some cases a significant quantity of the beta cell mass transplanted dies acutely following the infusion into the portal vein, the most clinically used site of engraftment. Subsequently, despite the majority of patients achieving insulin independence after transplant, a proportion of them recommence small, supplemental exogenous insulin over time. Herein, this review considers the process of islet revascularization after transplant, its limiting factors, and potential strategies to improve this critical step. Furthermore, we provide a characterization of alternative transplant sites, analyzing the historical evolution and their role towards advancing transplant outcomes in both the experimental and clinical settings.
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55
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Stützer I, Selevsek N, Esterházy D, Schmidt A, Aebersold R, Stoffel M. Systematic proteomic analysis identifies β-site amyloid precursor protein cleaving enzyme 2 and 1 (BACE2 and BACE1) substrates in pancreatic β-cells. J Biol Chem 2013; 288:10536-47. [PMID: 23430253 DOI: 10.1074/jbc.m112.444703] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Expansion of functional islet β-cell mass is a physiological process to compensate for increased insulin demand. Deficiency or pharmacological inhibition of the plasma membrane protease BACE2 enhances pancreatic β-cell function and proliferation, and therefore BACE2 is a putative target for the therapeutic intervention under conditions of β-cell loss and dysfunction. To gain a molecular understanding of BACE2 function, we performed a systematic and quantitative proteomic analysis to map the natural substrate repertoire of BACE2 and its homologue BACE1 in β-cells. Loss- and gain-of-function studies of in vitro and in vivo models identified specific and functionally heterogeneous targets. Our analysis revealed non-redundant roles of BACE1/2 in ectodomain shedding with BACE1 regulating a broader and BACE2 a more distinct set of β-cell-enriched substrates including two proteins of the seizure 6 protein family (SEZ6L and SEZ6L2). Lastly, our study provides insights into the global β-cell sheddome and secretome, an important prerequisite to uncover novel mechanisms contributing to β-cell homeostasis and a resource for therapeutic target and biomarker discoveries.
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Affiliation(s)
- Ina Stützer
- Department of Biology, Institute of Molecular Health Sciences, ETH Zürich, CH-8093 Zürich, Switzerland
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56
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Redox homeostasis in pancreatic β cells. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2012; 2012:932838. [PMID: 23304259 PMCID: PMC3532876 DOI: 10.1155/2012/932838] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Accepted: 10/30/2012] [Indexed: 12/20/2022]
Abstract
We reviewed mechanisms that determine reactive oxygen species (redox) homeostasis, redox information signaling and metabolic/regulatory function of autocrine insulin signaling in pancreatic β cells, and consequences of oxidative stress and dysregulation of redox/information signaling for their dysfunction. We emphasize the role of mitochondrion in β cell molecular physiology and pathology, including the antioxidant role of mitochondrial uncoupling protein UCP2. Since in pancreatic β cells pyruvate cannot be easily diverted towards lactate dehydrogenase for lactate formation, the respiration and oxidative phosphorylation intensity are governed by the availability of glucose, leading to a certain ATP/ADP ratio, whereas in other cell types, cell demand dictates respiration/metabolism rates. Moreover, we examine the possibility that type 2 diabetes mellitus might be considered as an inevitable result of progressive self-accelerating oxidative stress and concomitantly dysregulated information signaling in peripheral tissues as well as in pancreatic β cells. It is because the redox signaling is inherent to the insulin receptor signaling mechanism and its impairment leads to the oxidative and nitrosative stress. Also emerging concepts, admiting participation of redox signaling even in glucose sensing and insulin release in pancreatic β cells, fit in this view. For example, NADPH has been firmly established to be a modulator of glucose-stimulated insulin release.
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Neutzsky-Wulff AV, Andreassen KV, Hjuler ST, Feigh M, Bay-Jensen AC, Zheng Q, Henriksen K, Karsdal MA. Future detection and monitoring of diabetes may entail analysis of both β-cell function and volume: how markers of β-cell loss may assist. J Transl Med 2012; 10:214. [PMID: 23110768 PMCID: PMC3499140 DOI: 10.1186/1479-5876-10-214] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2012] [Accepted: 10/18/2012] [Indexed: 12/21/2022] Open
Abstract
Disease heterogeneity is as major issue in Type II Diabetes Mellitus (T2DM), and this patient inter-variability might not be sufficiently reflected by measurements of glycated haemoglobin (HbA1c).Β-cell dysfunction and β-cell death are initiating factors in development of T2DM. In fact, β-cells are known vanish prior to the development of T2DM, and autopsy of overt T2DM patients have shown a 60% reduction in β-cell mass.As the decline in β-cell function and mass have been proven to be pathological traits in T2DM, methods for evaluating β-cell loss is becoming of more interest. However, evaluation of β-cell death or loss is currently invasive and unattainable for the vast majority of diabetes patients. Serological markers, reflecting β-cell loss would be advantageous to detect and monitor progression of T2DM. Biomarkers with such capacities could be neo-epitopes of proteins with high β-cell specificity containing post translational modifications. Such tools may segregate T2DM patients into more appropriate treatment groups, based on their β-cell status, which is currently not possible. Presently individuals presenting with adequately elevated levels of both insulin and glucose are classified as T2DM patients, while an important subdivision of those is pending, namely those patients with sufficient β-cell capacity and those without. This may warrant two very different treatment options and patient care paths.Serological biomarkers reflecting β-cell health status may also assist development of new drugs for T2DM and aid physicians in better characterization of individual patients and tailor individual treatments and patient care protocols.
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Affiliation(s)
| | - Kim V Andreassen
- Nordic Bioscience A/S, Herlev Hovedgade 207, DK-2730, Herlev, Denmark
| | - Sara T Hjuler
- Nordic Bioscience A/S, Herlev Hovedgade 207, DK-2730, Herlev, Denmark
| | - Michael Feigh
- Nordic Bioscience A/S, Herlev Hovedgade 207, DK-2730, Herlev, Denmark
| | | | | | - Kim Henriksen
- Nordic Bioscience A/S, Herlev Hovedgade 207, DK-2730, Herlev, Denmark
| | - Morten A Karsdal
- Nordic Bioscience A/S, Herlev Hovedgade 207, DK-2730, Herlev, Denmark
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58
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Tsolakis AV, Grimelius L, Islam MS. Expression of the coiled coil domain containing protein 116 in the pancreatic islets and endocrine pancreatic tumors. Islets 2012; 4:349-53. [PMID: 23072936 PMCID: PMC3524142 DOI: 10.4161/isl.22416] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
AIMS Coiled coil domain containing protein 116 (CCDC116) is a product of the gene coiled coil domain containing 116 located on human chromosome 22. Its function has not yet been established. The present study focuses on the expression of this protein in human pancreatic islets and in the endocrine pancreatic tumors (EPTs). METHODS AND RESULTS Expression of the protein was evaluated by immunohistochemistry in endocrine pancreas from six patients and in various EPTs from 51 patients. In pancreatic islets, virtually all insulin, approx. 75% of the somatostatin, and approx. 60% of the pancreatic polypeptide (PP) cells were immunoreactive for the CCDC116 protein whereas glucagon, ghrelin and the exocrine cells were not. All insulinomas, gastrinomas, non-functioning sporadic tumors and the hereditary multihormonal EPTs were immunoreactive with variable relative incidence. Two of the three somatostatinomas, and one of the three ACTH-secreting tumors also expressed CCDC116. CONCLUSIONS The CCDC116 protein is expressed in all islet cell types except the glucagon and ghrelin cells. Most of the EPTs also contained CCDC116 protein. These findings suggest that this protein may play some role for the above mentioned endocrine cells and tumors. Its function has to be investigated in future studies.
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Affiliation(s)
- Apostolos V Tsolakis
- Department of Medical Sciences, Section of Endocrine Oncology, Uppsala University, Uppsala, Sweden.
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59
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Abstract
The pancreatic beta cell is responsible for maintaining normoglycaemia by secreting an appropriate amount of insulin according to blood glucose levels. The accurate sensing of the beta cell extracellular environment is therefore crucial to this endocrine function and is transmitted via its cell surface proteome. Various surface proteins that mediate or affect beta cell endocrine function have been identified, including growth factor and cytokine receptors, transporters, ion channels and proteases, attributing important roles to surface proteins in the adaptive behaviour of beta cells in response to acute and chronic environmental changes. However, the largely unknown composition of the beta cell surface proteome is likely to harbour yet more information about these mechanisms and provide novel points of therapeutic intervention and diagnostic tools. This article will provide an overview of the functional complexity of the beta cell surface proteome and selected surface proteins, outline the mechanisms by which their activity may be modulated, discuss the methods and challenges of comprehensively mapping and studying the beta cell surface proteome, and address the potential of this interesting subproteome for diagnostic and therapeutic applications in human disease.
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Affiliation(s)
- I. Stützer
- Institute of Molecular Systems Biology, HPT E73, ETH Zurich, Wolfgang-Pauli-Str. 16, 8093 Zurich, Switzerland
- Competence Center for Systems Physiology and Metabolic Diseases, ETH Zurich, Zurich, Switzerland
| | - D. Esterházy
- Institute of Molecular Systems Biology, HPT E73, ETH Zurich, Wolfgang-Pauli-Str. 16, 8093 Zurich, Switzerland
- Competence Center for Systems Physiology and Metabolic Diseases, ETH Zurich, Zurich, Switzerland
| | - M. Stoffel
- Institute of Molecular Systems Biology, HPT E73, ETH Zurich, Wolfgang-Pauli-Str. 16, 8093 Zurich, Switzerland
- Competence Center for Systems Physiology and Metabolic Diseases, ETH Zurich, Zurich, Switzerland
- Faculty of Medicine, University of Zurich, Zurich, Switzerland
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60
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Campbell-Thompson ML, Heiple T, Montgomery E, Zhang L, Schneider L. Staining protocols for human pancreatic islets. J Vis Exp 2012:e4068. [PMID: 22665223 DOI: 10.3791/4068] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Estimates of islet area and numbers and endocrine cell composition in the adult human pancreas vary from several hundred thousand to several million and beta mass ranges from 500 to 1500 mg. With this known heterogeneity, a standard processing and staining procedure was developed so that pancreatic regions were clearly defined and islets characterized using rigorous histopathology and immunolocalization examinations. Standardized procedures for processing human pancreas recovered from organ donors are described in part 1 of this series. The pancreas is processed into 3 main regions (head, body, tail) followed by transverse sections. Transverse sections from the pancreas head are further divided, as indicated based on size, and numbered alphabetically to denote subsections. This standardization allows for a complete cross sectional analysis of the head region including the uncinate region which contains islets composed primarily of pancreatic polypeptide cells to the tail region. The current report comprises part 2 of this series and describes the procedures used for serial sectioning and histopathological characterization of the pancreatic paraffin sections with an emphasis on islet endocrine cells, replication, and T-cell infiltrates. Pathology of pancreatic sections is intended to characterize both exocrine, ductular, and endocrine components. The exocrine compartment is evaluated for the presence of pancreatitis (active or chronic), atrophy, fibrosis, and fat, as well as the duct system, particularly in relationship to the presence of pancreatic intraductal neoplasia. Islets are evaluated for morphology, size, and density, endocrine cells, inflammation, fibrosis, amyloid, and the presence of replicating or apoptotic cells using H&E and IHC stains. The final component described in part 2 is the provision of the stained slides as digitized whole slide images. The digitized slides are organized by case and pancreas region in an online pathology database creating a virtual biobank. Access to this online collection is currently provided to over 200 clinicians and scientists involved in type 1 diabetes research. The online database provides a means for rapid and complete data sharing and for investigators to select blocks for paraffin or frozen serial sections.
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61
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Kanatsuna N, Papadopoulos GK, Moustakas AK, Lenmark Å. Etiopathogenesis of insulin autoimmunity. ANATOMY RESEARCH INTERNATIONAL 2012; 2012:457546. [PMID: 22567309 PMCID: PMC3335545 DOI: 10.1155/2012/457546] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Accepted: 01/12/2012] [Indexed: 12/12/2022]
Abstract
Autoimmunity against pancreatic islet beta cells is strongly associated with proinsulin, insulin, or both. The insulin autoreactivity is particularly pronounced in children with young age at onset of type 1 diabetes. Possible mechanisms for (pro)insulin autoimmunity may involve beta-cell destruction resulting in proinsulin peptide presentation on HLA-DR-DQ Class II molecules in pancreatic draining lymphnodes. Recent data on proinsulin peptide binding to type 1 diabetes-associated HLA-DQ2 and -DQ8 is reviewed and illustrated by molecular modeling. The importance of the cellular immune reaction involving cytotoxic CD8-positive T cells to kill beta cells through Class I MHC is discussed along with speculations of the possible role of B lymphocytes in presenting the proinsulin autoantigen over and over again through insulin-carrying insulin autoantibodies. In contrast to autoantibodies against other islet autoantigens such as GAD65, IA-2, and ZnT8 transporters, it has not been possible yet to standardize the insulin autoantibody test. As islet autoantibodies predict type 1 diabetes, it is imperative to clarify the mechanisms of insulin autoimmunity.
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Affiliation(s)
- Norio Kanatsuna
- Department of Clinical Sciences, Skåne University Hospital (SUS), Lund University, CRC Ing 72 Building 91:10, 205 02 Malmö, Sweden
| | - George K. Papadopoulos
- Laboratory of Biochemistry and Biophysics, Faculty of Agricultural Technology, Technological Educational Institute of Epirus, 47100 Arta, Greece
| | - Antonis K. Moustakas
- Department of Organic Farming, Technological Educational Institute of Ionian Islands, 27100 Argostoli, Greece
| | - Åke Lenmark
- Department of Clinical Sciences, Skåne University Hospital (SUS), Lund University, CRC Ing 72 Building 91:10, 205 02 Malmö, Sweden
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Schoennagel BP, Habermann CR, Roesch M, Hahne JD, Arndt C, Kleibeler L, Petersen KU, Graessner J, Adam G, Herrmann J. Diffusion-weighted imaging of the healthy pancreas: Apparent diffusion coefficient values of the normal head, body, and tail calculated from different sets of b-values. J Magn Reson Imaging 2011; 34:861-5. [DOI: 10.1002/jmri.22743] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Accepted: 07/18/2011] [Indexed: 02/01/2023] Open
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