51
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Benussi A, Padovani A, Borroni B. Phenotypic Heterogeneity of Monogenic Frontotemporal Dementia. Front Aging Neurosci 2015; 7:171. [PMID: 26388768 PMCID: PMC4555036 DOI: 10.3389/fnagi.2015.00171] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 08/19/2015] [Indexed: 12/12/2022] Open
Abstract
Frontotemporal dementia (FTD) is a genetically and pathologically heterogeneous disorder characterized by personality changes, language impairment, and deficits of executive functions associated with frontal and temporal lobe degeneration. Different phenotypes have been defined on the basis of presenting clinical symptoms, i.e., the behavioral variant of FTD, the agrammatic variant of primary progressive aphasia, and the semantic variant of PPA. Some patients have an associated movement disorder, either parkinsonism, as in progressive supranuclear palsy and corticobasal syndrome, or motor neuron disease (FTD-MND). A family history of dementia is found in 40% of cases of FTD and about 10% have a clear autosomal-dominant inheritance. Genetic studies have identified several genes associated with monogenic FTD: microtubule-associated protein tau, progranulin, TAR DNA-binding protein 43, valosin-containing protein, charged multivesicular body protein 2B, fused in sarcoma, and the hexanucleotide repeat expansion in intron 1 of the chromosome 9 open reading frame 72. Patients often present with an extensive phenotypic variability, even among different members of the same kindred carrying an identical disease mutation. The objective of the present work is to review and evaluate available literature data in order to highlight recent advances in clinical, biological, and neuroimaging features of monogenic frontotemporal lobar degeneration and try to identify different mechanisms underlying the extreme phenotypic heterogeneity that characterizes this disease.
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Affiliation(s)
- Alberto Benussi
- Centre for Ageing Brain and Neurodegenerative Disorders, Neurology Unit, Department of Clinical and Experimental Sciences, University of Brescia, Brescia, Italy
| | - Alessandro Padovani
- Centre for Ageing Brain and Neurodegenerative Disorders, Neurology Unit, Department of Clinical and Experimental Sciences, University of Brescia, Brescia, Italy
| | - Barbara Borroni
- Centre for Ageing Brain and Neurodegenerative Disorders, Neurology Unit, Department of Clinical and Experimental Sciences, University of Brescia, Brescia, Italy
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52
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Chang L, Monteiro MJ. Defective Proteasome Delivery of Polyubiquitinated Proteins by Ubiquilin-2 Proteins Containing ALS Mutations. PLoS One 2015; 10:e0130162. [PMID: 26075709 PMCID: PMC4468220 DOI: 10.1371/journal.pone.0130162] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 05/17/2015] [Indexed: 12/14/2022] Open
Abstract
Ubiquilin proteins facilitate delivery of ubiquitinated proteins to the proteasome for degradation. Interest in the proteins has been heightened by the discovery that gene mutations in UBQLN2 cause dominant inheritance of amyotrophic lateral sclerosis (ALS). However, the mechanisms by which the mutations cause ALS are not known. Here we report on the underlying defect of ubiquilin-2 proteins containing ALS-linked mutations in affecting proteasome-mediated degradation. We found that overexpression of ubiquilin-2 proteins containing any one of five different ALS mutations slow degradation of Myc, a prototypic proteasome substrate. Examination of coprecipitating proteins indicated that the mutant proteins are generally capable of binding polyubiquitinated proteins, but defective in binding the proteasome. GST-pulldown studies revealed that many of the mutants bind weaker to the S5a subunit of the proteasome, compared with wild type (WT) ubiquilin-2 protein. The results suggest the mutant proteins are unable to deliver their captured cargo to the proteasome for degradation, which presumably leads to toxicity. Quantification of cell death is consistent with this idea. Measurement of protein turnover further indicated the mutant proteins have longer half-lives than WT ubiquilin-2. Our studies provide novel insight into the mechanism by which ALS-linked mutations in UBQLN2 interfere with protein degradation.
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Affiliation(s)
- Lydia Chang
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Mervyn J. Monteiro
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- * E-mail:
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53
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Evaluation of Skin Fibroblasts from Amyotrophic Lateral Sclerosis Patients for the Rapid Study of Pathological Features. Neurotox Res 2015; 28:138-46. [PMID: 26013250 DOI: 10.1007/s12640-015-9532-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Revised: 05/01/2015] [Accepted: 05/14/2015] [Indexed: 12/20/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder characterised by the progressive degeneration of brain and spinal cord motor neurons. Ubiquitin-proteasome system (UPS) dysfunction and oxidative stress have been implicated in ALS pathogenesis. However, it is unknown whether the defects in these pathways extend to non-neuronal tissues such as fibroblasts. Fibroblasts, unlike neuronal tissue, are readily available and may hold potential for short-term, rapid diagnostic and prognostic purposes. We investigated whether primary skin fibroblasts from ALS patients share, or can be manipulated to develop, functional and pathological abnormalities seen in affected neuronal cells. We inhibited UPS function and induced oxidative stress in the fibroblasts and found that ALS-related cellular changes, such as aggregate formation and ubiquitination of ALS-associated proteins (TDP-43 and ubiquilin 2), can be reproduced in these cells. Higher levels of TDP-43 ubiquitination, as evident by colocalization between TDP-43 and ubiquitin, were found in all six ALS cases compared to controls following extracellular insults. In contrast, colocalization between ubiquilin 2 and ubiquitin was not markedly different between ALS cases and control. A UPS reporter assay revealed UPS abnormalities in patient fibroblasts. Despite the presence of ALS-related cellular changes in the patient fibroblasts, no elevated toxicity was observed. This suggests that aggregate formation and colocalization of ALS-associated proteins may be insufficient alone to confer toxicity in fibroblasts used in the present study. Chronic exposure to ALS-linked stresses and the ALS-linked cellular pathologies may be necessary to breach an unknown threshold that triggers cell death.
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54
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Defining the genetic connection linking amyotrophic lateral sclerosis (ALS) with frontotemporal dementia (FTD). Trends Genet 2015; 31:263-73. [DOI: 10.1016/j.tig.2015.03.005] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Revised: 03/10/2015] [Accepted: 03/10/2015] [Indexed: 12/11/2022]
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55
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Autophagy receptor defects and ALS-FTLD. Mol Cell Neurosci 2015; 66:43-52. [PMID: 25683489 DOI: 10.1016/j.mcn.2015.01.002] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 01/16/2015] [Accepted: 01/27/2015] [Indexed: 12/11/2022] Open
Abstract
Various pathophysiological mechanisms have been implicated in the ALS-FTLD clinicopathological spectrum of neurodegenerative disorders. Here we focus on the role of autophagy, an intracellular catabolic pathway, in these conditions. Growing evidence suggests that the autophagic process can be disturbed in ALS-FTLD, including by genetic mutations affecting autophagy receptor proteins (ubiquilin-2, optineurin, SQSTM1/p62) and regulators (VCP). Such mutations may impair clearance of autophagy substrates with pathological consequences. Recent studies have also uncovered a direct connection between autophagy and RNA processing, supporting an integrated model connecting several ALS-FTLD associated gene products. This article is part of a Special Issue entitled 'Neuronal Protein'.
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56
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The distinct genetic pattern of ALS in Turkey and novel mutations. Neurobiol Aging 2015; 36:1764.e9-1764.e18. [PMID: 25681989 DOI: 10.1016/j.neurobiolaging.2014.12.032] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Revised: 10/15/2014] [Accepted: 12/26/2014] [Indexed: 11/22/2022]
Abstract
The frequency of amyotrophic lateral sclerosis (ALS) mutations has been extensively investigated in several populations; however, a systematic analysis in Turkish cases has not been reported so far. In this study, we screened 477 ALS patients for mutations, including 116 familial ALS patients from 82 families and 361 sporadic ALS (sALS) cases. Patients were genotyped for C9orf72 (18.3%), SOD1 (12.2%), FUS (5%), TARDBP (3.7%), and UBQLN2 (2.4%) gene mutations, which together account for approximately 40% of familial ALS in Turkey. No SOD1 mutations were detected in sALS patients; however, C9orf72 (3.1%) and UBQLN2 (0.6%) explained 3.7% of sALS in the population. Exome sequencing revealed mutations in OPTN, SPG11, DJ1, PLEKHG5, SYNE1, TRPM7, and SQSTM1 genes, many of them novel. The spectrum of mutations reflect both the distinct genetic background and the heterogeneous nature of the Turkish ALS population.
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57
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Dual Role of Autophagy in Neurodegenerative Diseases: The Case of Amyotrophic Lateral Sclerosis. CURRENT TOPICS IN NEUROTOXICITY 2015. [DOI: 10.1007/978-3-319-13939-5_4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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58
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Ng ASL, Rademakers R, Miller BL. Frontotemporal dementia: a bridge between dementia and neuromuscular disease. Ann N Y Acad Sci 2014; 1338:71-93. [PMID: 25557955 DOI: 10.1111/nyas.12638] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The concept that frontotemporal dementia (FTD) is a purely cortical dementia has largely been refuted by the recognition of its close association with motor neuron disease, and the identification of transactive response DNA-binding protein 43 (TDP-43) as a major pathological substrate underlying both diseases. Genetic findings have transformed this field and revealed connections between disorders that were previous thought clinically unrelated. The discovery that the C9ORF72 locus is responsible for the majority of hereditary FTD, amyotrophic lateral sclerosis (ALS), and FTD-ALS cases and the understanding that repeat-containing RNA plays a crucial role in pathogenesis of both disorders has paved the way for the development of potential biomarkers and therapeutic targets for these devastating diseases. In this review, we summarize the historical aspects leading up to our current understanding of the genetic, clinical, and neuropathological overlap between FTD and ALS, and include brief discussions on chronic traumatic encephalopathy (CTE), given its association with TDP-43 pathology, its associated increased dementia risk, and reports of ALS in CTE patients. In addition, we describe other genetic associations between dementia and neuromuscular disease, such as inclusion body myositis with Paget's disease and FTD.
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Affiliation(s)
- Adeline S L Ng
- Department of Neurology, National Neuroscience Institute, Tan Tock Seng Hospital, Novena, Singapore
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59
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Abstract
Our understanding of amyotrophic lateral sclerosis (ALS), a fatal neurodegenerative disease, is expanding rapidly as its genetic causes are uncovered. The pace of new gene discovery over the last 5 years has accelerated, providing new insights into the pathogenesis of disease and highlighting biological pathways as targets for therapeutic development. This article reviews our current understanding of the heritability of ALS and provides an overview of each of the major ALS genes, highlighting their phenotypic characteristics and frequencies as a guide for clinicians evaluating patients with ALS.
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Affiliation(s)
- Matthew B Harms
- Neuromuscular Division, Department of Neurology, Hope Center for Neurological Disorders, Washington University School of Medicine, 660 South Euclid Avenue, St Louis, MO 63110, USA.
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60
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Fahed AC, McDonough B, Gouvion CM, Newell KL, Dure LS, Bebin M, Bick AG, Seidman JG, Harter DH, Seidman CE. UBQLN2 mutation causing heterogeneous X-linked dominant neurodegeneration. Ann Neurol 2014; 75:793-798. [PMID: 24771548 DOI: 10.1002/ana.24164] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Revised: 04/23/2014] [Accepted: 04/23/2014] [Indexed: 12/13/2022]
Abstract
We report a 5-generation family with phenotypically diverse neurodegenerative disease including relentlessly progressive choreoathetoid movements, dysarthria, dysphagia, spastic paralysis, and behavioral dementia in descendants of a 67-year-old woman with amyotrophic lateral sclerosis. Disease onset varied with gender, occurring in male children and adult women. Exome sequence analyses revealed a novel mutation (c.1490C>T, p.P497L) in the ubiquilin-2 gene (UBQLN2) with X-linked inheritance in all studied affected individuals. As ubiquilin-2-positive inclusions were identified in brain, we suggest that mutant peptide predisposes to protein misfolding and accumulation. Our findings expand the spectrum of neurodegenerative phenotypes caused by UBQLN2 mutations.
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Affiliation(s)
- Akl C Fahed
- Department of Genetics, Harvard Medical School, Boston, MA
| | - Barbara McDonough
- Department of Genetics, Harvard Medical School, Boston, MA.,Cardiovascular Division and Howard Hughes Medical Institute, Brigham and Women's Hospital, Boston, MA
| | - Cynthia M Gouvion
- Departments of Pathology and Laboratory Medicine, University of Kansas Medical Center, Kansas City, KS
| | - Kathy L Newell
- Departments of Pathology and Laboratory Medicine, University of Kansas Medical Center, Kansas City, KS
| | - Leon S Dure
- Departments of Neurology and Pediatrics, University of Alabama at Birmingham, Birmingham, AL
| | - Martina Bebin
- Departments of Neurology and Pediatrics, University of Alabama at Birmingham, Birmingham, AL
| | | | - J G Seidman
- Department of Genetics, Harvard Medical School, Boston, MA
| | - Donald H Harter
- Department of Neurology, School of Medicine & Health Sciences, The George Washington University, Washington, DC
| | - Christine E Seidman
- Department of Genetics, Harvard Medical School, Boston, MA.,Cardiovascular Division and Howard Hughes Medical Institute, Brigham and Women's Hospital, Boston, MA
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61
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Zhang KY, Yang S, Warraich ST, Blair IP. Ubiquilin 2: A component of the ubiquitin–proteasome system with an emerging role in neurodegeneration. Int J Biochem Cell Biol 2014; 50:123-6. [DOI: 10.1016/j.biocel.2014.02.018] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Revised: 02/14/2014] [Accepted: 02/20/2014] [Indexed: 12/12/2022]
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62
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Su XW, Broach JR, Connor JR, Gerhard GS, Simmons Z. Genetic heterogeneity of amyotrophic lateral sclerosis: Implications for clinical practice and research. Muscle Nerve 2014; 49:786-803. [DOI: 10.1002/mus.24198] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/29/2014] [Indexed: 12/26/2022]
Affiliation(s)
- Xiaowei W. Su
- Department of Neurosurgery; The Pennsylvania State University College of Medicine; Hershey Pennsylvania USA
| | - James R. Broach
- Department of Biochemistry and Molecular Biology; The Pennsylvania State University College of Medicine; Hershey Pennsylvania USA
| | - James R. Connor
- Department of Neurosurgery; The Pennsylvania State University College of Medicine; Hershey Pennsylvania USA
| | - Glenn S. Gerhard
- Department of Biochemistry and Molecular Biology; The Pennsylvania State University College of Medicine; Hershey Pennsylvania USA
| | - Zachary Simmons
- Department of Neurology; Penn State Milton S. Hershey Medical Center; 30 Hope Drive (Suite EC037) Hershey Pennsylvania 17033 USA
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63
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Recent progress in the genetics of motor neuron disease. Eur J Med Genet 2014; 57:103-12. [DOI: 10.1016/j.ejmg.2014.01.002] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Accepted: 01/14/2014] [Indexed: 01/07/2023]
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64
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UBQLN2 mutations are not a frequent cause of amyotrophic lateral sclerosis in Ireland. Neurobiol Aging 2014; 35:267.e9-11. [DOI: 10.1016/j.neurobiolaging.2013.07.023] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Accepted: 07/22/2013] [Indexed: 11/21/2022]
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65
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Ling SC, Polymenidou M, Cleveland DW. Converging mechanisms in ALS and FTD: disrupted RNA and protein homeostasis. Neuron 2013; 79:416-38. [PMID: 23931993 DOI: 10.1016/j.neuron.2013.07.033] [Citation(s) in RCA: 1223] [Impact Index Per Article: 111.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/24/2013] [Indexed: 12/12/2022]
Abstract
Breakthrough discoveries identifying common genetic causes for amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) have transformed our view of these disorders. They share unexpectedly similar signatures, including dysregulation in common molecular players including TDP-43, FUS/TLS, ubiquilin-2, VCP, and expanded hexanucleotide repeats within the C9ORF72 gene. Dysfunction in RNA processing and protein homeostasis is an emerging theme. We present the case here that these two processes are intimately linked, with disease-initiated perturbation of either leading to further deviation of both protein and RNA homeostasis through a feedforward loop including cell-to-cell prion-like spread that may represent the mechanism for relentless disease progression.
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Affiliation(s)
- Shuo-Chien Ling
- Ludwig Institute for Cancer Research, University of California at San Diego, La Jolla, CA 92093-0670, USA
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66
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THEME 7 GENETICS. Amyotroph Lateral Scler Frontotemporal Degener 2013. [DOI: 10.3109/21678421.2013.838422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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67
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Genetics of frontotemporal lobar degeneration: An up-date and diagnosis algorithm. Rev Neurol (Paris) 2013; 169:811-9. [DOI: 10.1016/j.neurol.2013.07.014] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Revised: 07/10/2013] [Accepted: 07/10/2013] [Indexed: 12/12/2022]
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68
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Vengoechea J, David MP, Yaghi SR, Carpenter L, Rudnicki SA. Clinical variability and female penetrance in X-linked familial FTD/ALS caused by a P506S mutation in UBQLN2. Amyotroph Lateral Scler Frontotemporal Degener 2013; 14:615-9. [DOI: 10.3109/21678421.2013.824001] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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