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  • 1
    Keywords: CELLS ; HEPATOCELLULAR-CARCINOMA ; MECHANISM ; COPY-NUMBER ; IMPORTIN-ALPHA ; HUMAN HOMOLOG ; SUSCEPTIBILITY GENE ; protein expression ; TARGET GENES ; SEGREGATION GENE CSE1
    Abstract: Proteins of the karyopherin superfamily including importins and exportins represent an essential part of the nucleocytoplasmic transport machinery. However, the functional relevance and regulation of karyopherins in hepatocellular carcinoma (HCC) is poorly understood. Here we identified cellular apoptosis susceptibility (CAS, exportin-2) and its transport substrate importin-alpha1 (imp-alpha1) among significantly up-regulated transport factor genes in HCC. Disruption of the CAS/imp-alpha1 transport cycle by RNAi in HCC cell lines resulted in decreased tumor cell growth and increased apoptosis. The apoptotic phenotype upon CAS depletion could be recapitulated by direct knockdown of the X-linked inhibitor of apoptosis (XIAP) and partially reverted by XIAP overexpression. In addition, XIAP and CAS mRNA expression levels were correlated in HCC patient samples (r=0.463; P〈0.01), supporting the in vivo relevance of our findings. Furthermore, quantitative mass spectrometry analyses of murine HCC samples (p53-/- versus p53+/+) indicated higher protein expression of CAS and imp-alpha1 in p53-/- tumors. Consistent with a role of p53 in regulating the CAS/imp-alpha1 transport cycle, we observed that both transport factors were repressed upon p53 induction in a p21-dependent manner. CONCLUSION: The CAS/imp-alpha1 transport cycle is linked to XIAP and is required to maintain tumor cell survival in HCC. Moreover, CAS and imp-alpha1 are targets of p53-mediated repression, which represents a novel aspect of p53's ability to control tumor cell growth in hepatocarcinogenesis.
    Type of Publication: Journal article published
    PubMed ID: 24799195
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  • 2
    Keywords: RECEPTOR ; APOPTOSIS ; CANCER CELLS ; CELLS ; EXPRESSION ; GROWTH ; tumor ; TUMOR-CELLS ; carcinoma ; Germany ; human ; INHIBITION ; PATHWAY ; PATHWAYS ; DEATH ; HEPATOCELLULAR-CARCINOMA ; PROTEINS ; RNA ; DRUG ; MONOCLONAL-ANTIBODY ; TUMORS ; RELEASE ; TUMOR-NECROSIS-FACTOR ; ACTIVATION ; LIGAND ; MECHANISM ; FAMILY ; DOMAIN ; INDUCTION ; mechanisms ; DOWN-REGULATION ; CYTOCHROME-C ; MITOCHONDRIA ; UNITED-STATES ; RECEPTORS ; OVEREXPRESSION ; TUMOR CELLS ; Bcl-2 ; HUMAN HEPATOCYTES ; TRAIL-INDUCED APOPTOSIS ; APOPTOSIS-INDUCING LIGAND ; CD95 ; CASPASE ; INHIBITORS ; signaling ; FAMILIES ; SOLID TUMORS ; CYCLOOXYGENASE-2 ; TUMOR-CELL ; death receptor ; downregulation ; function ; caspases ; DRUGS ; cyclooxygenase ; RELEVANCE ; NECROSIS ; MCL-1 ; CELECOXIB-INDUCED APOPTOSIS ; PRIMARY HUMAN HEPATOCYTES
    Abstract: Inhibition of cyclooxygenase (COX)-2 elicits chemopreventive and therapeutic effects in solid tumors that are coupled with the induction of apoptosis in tumor cells. We investigated the mechanisms by which COX-2 inhibition induces apoptosis in hepatocellular carcinoma (HCC) cells. COX-2 inhibition triggered expression of the CD95, tumor necrosis factor (TNIF)-R, and TNF-related apoptosis-inducing ligand (TRAIL)-R1 and TRAIL-R2 death receptors. Addition of the respective specific ligands further increased apoptosis, indicating that COX-2 inhibition induced the expression of functional death receptors. Overexpression of a dominant-negative Fas-associated death domain mutant reduced COX-2 inhibitor-mediated apoptosis. Furthermore, our findings showed a link between COX-2 inhibition and the mitochondrial apoptosis pathway. COX-2 inhibition led to a rapid down-regulation of myeloid cc leukemia-1 (Mcl-1), an antiapoptotic member of the Bcl-2 family, followed by translocation of Bax to mitochondria and cytochrome c release front mitochondria. Consequently, overexpression of Mcl-1 led to inhibition of COX-2 inhibitor-mediated apoptosis. Furthermore, blocking endogenous Mcl-1 function using a small - interfering RNA approach enhanced COX-2 inhibitor-mediated apoptosis. It is of clinical importance that celecoxib acted synergistically with chemotherapeutic drugs in the induction of apoptosis in HCC cells. The clinical relevance of these results is further substantiated by the finding that COX-2 inhibitors did not sensitize primary human hepatocytes toward chemotherapy-induced apoptosis. In conclusion, COX-2 inhibition engages different apoptosis pathways in HCC cells stimulating death receptor signaling, activation of caspases, and apoptosis originating from mitochondria
    Type of Publication: Journal article published
    PubMed ID: 16849551
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  • 3
    Keywords: RECEPTOR ; CELLS ; IN-VITRO ; SKIN ; PHOSPHORYLATION ; IDENTIFICATION ; MORPHOGENESIS ; HEPATOCYTE GROWTH-FACTOR ; C-MET ; REEPITHELIALIZATION
    Abstract: Cutaneous regeneration utilizes paracrine feedback mechanisms to fine-tune the regulation of epidermal keratinocyte proliferation and migration. However, it is unknown how fibroblast-derived hepatocyte growth factor (HGF) affects these mutually exclusive processes in distinct cell populations. We here show that HGF stimulates the expression and phosphorylation of the microtubule-destabilizing factor stathmin in primary human keratinocytes. Quantitative single cell- and cell population-based analyses revealed that basal stathmin levels are important for the migratory ability of keratinocytes in vitro; however, its expression is moderately induced in the migration tongue of mouse skin or organotypic multi-layered keratinocyte 3D cultures after full-thickness wounding. In contrast, clearly elevated stathmin expression is detectable in hyperproliferative epidermal areas. In vitro, stathmin silencing significantly reduced keratinocyte proliferation. Automated quantitative and time-resolved analyses in organotypic cocultures demonstrated a high correlation between Stathmin/phospho-Stathmin and Ki67 positivity in epidermal regions with proliferative activity. Thus, activation of stathmin may stimulate keratinocyte proliferation, while basal stathmin levels are sufficient for keratinocyte migration during cutaneous regeneration.
    Type of Publication: Journal article published
    PubMed ID: 24066165
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  • 4
    Keywords: CANCER ; CELLS ; EXPRESSION ; INVASION ; proliferation ; tumor ; TUMOR-CELLS ; carcinoma ; CELL ; Germany ; human ; INHIBITION ; LUNG ; COMMON ; lung cancer ; LUNG-CANCER ; HEPATOCELLULAR-CARCINOMA ; GENE-EXPRESSION ; PROTEIN ; PROTEINS ; LINES ; FAMILY ; TISSUES ; DYNAMICS ; CELL-LINES ; DOWN-REGULATION ; MEMBERS ; SEQUENCE ; TARGET ; LOCALIZATION ; MIGRATION ; MICROTUBULES ; MORPHOLOGY ; adenocarcinoma ; squamous cell carcinoma ; OVEREXPRESSION ; cell lines ; non-small cell lung cancer ; HUMAN BREAST-CANCER ; MATRIX ; CELL CARCINOMA ; FAMILIES ; cell proliferation ; USA ; MICROTUBULE DYNAMICS ; MOTILITY ; SQUAMOUS-CELL ; MALIGNANT PHENOTYPE ; therapeutic ; WELL ; CELL-LUNG-CANCER ; additive ; HUMAN HEPATOCARCINOGENESIS ; MYC EXPRESSION
    Abstract: Dynamic instability of the microtubule network modulates processes such as cell division and motility, as well as cellular morphology. Overexpression of the microtubule-destabilizing phosphoprotein stathmin is frequent in human malignancies and represents a promising therapeutic target. Although stathmin inhibition gives rise to antineoplastic effects, additional and functionally redundant microtubule-interacting proteins may attenuate the efficiency of this therapeutic approach. We have systematically analyzed the expression and potential protumorigenic effects of stathmin family members in human non-small cell lung cancer (NSCLC). Both stathmin and stathmin-like 3 (SCLIP) were overexpressed in adenocarcinoma as well as squamous cell carcinoma (SCC) tissues and induced tumor cell proliferation, migration, and matrix invasion in respective cell lines. Accordingly, reduced stathmin and SCLIP levels affected cell morphology and were associated with a less malignant phenotype. Combine inhibition of both factors caused additive effects on tumor cell motility, indicating partial functional redundancy. Because stathmin and SCLIP expression significantly correlated in NSCLC tissues, we searched for common upstream regulators and identified the far upstream sequence element-binding protein-1 (FBP-1) as a pivotal inducer of several stathmin family members. Our results indicate that the coordinated overexpression of microtubule-destabilizing factors by FBP-1 is a critical step to facilitate microtubule dynamics and subsequently increases proliferation and motility of tumor cells. [Cancer Res 2009;69(6):2234-43]
    Type of Publication: Journal article published
    PubMed ID: 19258502
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  • 5
    Keywords: CANCER ; CELLS ; EXPRESSION ; GROWTH ; SURVIVAL ; carcinoma ; CELL ; Germany ; human ; MODEL ; PATHWAY ; PATHWAYS ; NETWORK ; SUPPORT ; DEATH ; HEPATOCELLULAR-CARCINOMA ; liver ; GENE ; GENES ; PROTEIN ; PROTEINS ; TISSUE ; NF-KAPPA-B ; ACTIVATION ; murine ; CARCINOGENESIS ; INDUCTION ; SIGNAL ; TARGET ; MOUSE ; hepatocarcinogenesis ; hepatocellular carcinoma ; PROGRESSION ; CELL-DEATH ; CELL-LINE ; SIGNALING PATHWAY ; SIGNALING PATHWAYS ; RAGE ; MOUSE MODEL ; KAPPA-B ; OXIDATIVE STRESS ; expression profiling ; inflammation ; signaling ; MOLECULAR-MECHANISMS ; cell death ; CANCER PROGRESSION ; USA ; GROWTH-CONTROL ; SUPPRESSOR-CELLS ; nuclear factor kappa B ; COEXPRESSION ; COMPENSATORY PROLIFERATION
    Abstract: The nuclear factor-kappaB (NF-kappa B) signaling pathway has been recently shown to participate in inflammation-induced cancer progression. Here, we describe a detailed analysis of the NF-kappa B-dependent gene regulatory network in the well-established Mdr2 knockout mouse model of inflammation-associated liver carcinogenesis. Expression profiling of NF-kappa B-deficient and NF-kappa B-proficient hepatocellular carcinoma (HCC) revealed a comprehensive list of known and novel putative NF-kappa B target genes, including S100a8 and S100a9. We detected increased co-expression of S100A8 and S100A9 proteins in mouse HCC cells, in human HCC tissue, and in the HCC cell line Hep3B on ectopic RelA expression. Finally, we found a synergistic function for S100A8 and S100A9 in Hep3B cells resulting in a significant induction of reactive oxygen species (ROS), accompanied by enhanced cell survival. Conclusion: We identified S100A8 and S100A9 as novel NF-kappa B target genes in HCC cells during inflammation-associated liver carcinogenesis and provide experimental evidence that increased co-expression of both proteins supports malignant progression by activation of ROS-dependent signaling pathways and protection from cell death. (HEPATOLOGY 2009;50: 1251-1262.)
    Type of Publication: Journal article published
    PubMed ID: 19670424
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  • 6
    Keywords: brain ; CANCER ; CANCER CELLS ; CELLS ; EXPRESSION ; GROWTH ; IN-VITRO ; INHIBITOR ; INVASION ; proliferation ; tumor ; CELL ; CELL-PROLIFERATION ; Germany ; human ; IN-VIVO ; MODEL ; VITRO ; VIVO ; GENE-EXPRESSION ; PROTEIN ; transcription ; cell line ; TISSUE ; TUMORS ; LINES ; MICE ; PATIENT ; TISSUES ; KERATINOCYTES ; SKIN ; T cell ; T-CELL ; CELL-LINES ; SIGNAL ; MOUSE ; STAGE ; UP-REGULATION ; MEMBRANE ; skin carcinogenesis ; CELL-LINE ; LINE ; ADHESION ; MIGRATION ; MORPHOLOGY ; INVOLVEMENT ; MOUSE MODEL ; TRANSLOCATION ; beta-catenin ; ECTODOMAIN ; cell lines ; SUBSTRATE-SPECIFICITY ; MATRIX ; E-cadherin ; ONCOLOGY ; RE ; CAPACITY ; keratinocyte ; cell proliferation ; LEVEL ; NUCLEAR ; USA ; TISSUE INHIBITOR ; cancer research ; in vivo ; PLASMID ; DEFECT ; PROMOTES ; matrix metalloproteinase ; METALLOPROTEINASE ; ectodomain shedding ; MATRIX-METALLOPROTEINASE ; OVARIAN-CARCINOMA ; GROWTH-CONTROL ; EXTRACELLULAR CLEAVAGE ; HUMAN TISSUE KALLIKREINS ; PROTEINASE-ACTIVATED RECEPTORS ; SERINE PROTEINASE ; SERUM BIOMARKER
    Abstract: Recently, we described phorbol ester-induced expression of the brain and skin serine proteinase Bssp/kallikrein 6 (Klk6), the mouse orthologue of human KLK6, in mouse back skin and in advanced tumor stages of a well-established multistage tumor model. Here, we show KLK6 up-regulation in squamous skin tumors of human patients and in tumors of other epithelial tissues. Ectopic Klk6 expression in mouse keratinocyte cell lines induces a spindle-like morphology associated with accelerated proliferation, migration, and invasion capacity. We found reduced E-cadherin protein levels in the cell membrane and nuclear translocation of beta-catenin in Klk6-expressing mouse keratinocytes and human HEK293 cells transfected with a KLK6 expression plasmid. Additionally, HEK293 cells exhibited induced T-cell factor-dependent transcription and impaired cell-cell adhesion in the presence of KLK6, which was accompanied by induced E-cadherin ectodomain shedding. Interestingly, tissue inhibitor of metalloproteinase (TIMP)-l and TIMP-3 interfere with KLK6-induced F-cadherin ectodomain shedding and rescue the cell-cell adhesion defect in vitro, suggesting the involvement of matrix metalloproteinase and/or a disintegrin and metalloproteinase (ADAM) proteolytic activity. In line with this assumption, we found increased levels of the mature 62-kDa ADAM10 proteinase in cells expressing ectopic KLK6 compared with mock controls. Finally, enhanced epidermal keratinocyte proliferation and migration in concert with decreased E-cadherin protein levels are confirmed in an in vivo Klk6 transgenic mouse model
    Type of Publication: Journal article published
    PubMed ID: 17804733
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  • 7
    Keywords: CANCER ; CELLS ; EXPRESSION ; carcinoma ; CELL ; Germany ; DISEASE ; DISEASES ; HEPATOCELLULAR-CARCINOMA ; liver ; PROTEIN ; RNA ; TISSUE ; LINES ; INFECTION ; CARCINOGENESIS ; CELL-LINES ; culture ; antibodies ; antibody ; virus ; STAGE ; hepatocellular carcinoma ; immunohistochemistry ; CELL-LINE ; LINE ; MELANOMA ; HEPATOMA ; LOCALIZATION ; CARCINOMAS ; cell lines ; NUCLEAR-PORE COMPLEX ; LIVER-DISEASE ; SPECIMENS ; VIRAL-DNA ; hepatitis B and C virus ; hepatocellular carcinogenesis ; nucleoporin 88 ; NUP88
    Abstract: AIM: To investigate the expression of nucleoporin 88 (Nup88) in hepatitis B virus (HBV) and C virus (HCV)related liver diseases. METHODS: We generated a new monoclonal Nup88 antibody to investigate the Nup88 protein expression by immunohistochemistry (IHC) in 294 paraffin-embedded liver specimens comprising all stages of hepatocellular carcinogenesis. In addition, in cell culture experiments HBV-positive (HepG2.2.15 and HB611) and HBV-negative (HepG2) hepatoma cell lines were tested for the Nup88 expression by Western-immunoblotting to test data obtained by IHC. RESULTS: Specific Nup88 expression was found in chronic HCV hepatitis and unspecific chronic hepatitis, whereas no or very weak Nup88 expression was detected in normal liver. The Nup88 expression was markedly reduced or missing in mild chronic HBV infection and inversely correlated with HBcAg expression. Irrespective of the HBV- or HCV-status, increasing Nup88 expression was observed in cirrhosis and dysplastic nodules, and Nup88 was highly expressed in hepatocellular carcinomas. The intensity of Nup88 expression significantly increased during carcinogenesis (P 〈 0.0001) and correlated with dedifferentiation (P 〈 0.0001). Interestingly, Nup88 protein expression was significantly downregulated in HBV-positive HepG2.2.15 (P 〈 0.002) and HB611 (P 〈 0.001) cell lines as compared to HBV-negative HepG2 cells. CONCLUSION: Based on our immunohistochemical data, HBV and HCV are unlikely to influence the expression of Nup88 in cirrhotic and neoplastic liver tissue, but point to an interaction of HBV with the nuclear pore in chronic hepatitis. The expression of Nup88 in nonneoplastic liver tissue might reflect enhanced metabolic activity of the liver tissue. Our data strongly indicate a dichotomous role for Nup88 in nonneoplastic and neoplastic conditions of the liver. (C) 2006 The WJG Press. All rights reserved
    Type of Publication: Journal article published
    PubMed ID: 17007055
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  • 8
    Keywords: CANCER ; CANCER CELLS ; CELLS ; EXPRESSION ; GROWTH ; IN-VITRO ; proliferation ; SURVIVAL ; tumor ; carcinoma ; CELL ; CELL-PROLIFERATION ; Germany ; human ; INHIBITION ; VITRO ; HEPATOCELLULAR-CARCINOMA ; liver ; GENE-EXPRESSION ; PROTEIN ; PROTEINS ; RNA ; TISSUE ; LINES ; PATIENT ; ACTIVATION ; MECHANISM ; FAMILY ; REDUCTION ; TISSUES ; CONTRAST ; mechanisms ; DYNAMICS ; BINDING ; CELL-LINES ; DOWN-REGULATION ; MEMBERS ; treatment ; TARGET ; ELEMENT ; polymer ; hepatocarcinogenesis ; hepatocellular carcinoma ; MOBILITY ; CELL-LINE ; CANCER-CELLS ; MIGRATION ; MORPHOLOGY ; PHENOTYPE ; BINDING-PROTEINS ; C-MYC ; OVEREXPRESSION ; cell lines ; MITOSIS ; BINDING PROTEIN ; HUMAN BREAST-CANCER ; FAMILIES ; TUMOR-GROWTH ; PATIENT SURVIVAL ; cell proliferation ; structure ; MOLECULAR-MECHANISMS ; LEVEL ; bioavailability ; STATHMIN ; USA ; MICROTUBULE DYNAMICS ; MOTILITY ; HUMAN HEPATOCELLULAR-CARCINOMA ; DIVISION ; MALIGNANT PHENOTYPE ; MODIFIERS ; HUMAN HEPATOCARCINOGENESIS
    Abstract: Microtubule-dependent effects are partly regulated by factors that coordinate polymer dynamics such as the microtubule-destabilizing protein stathmin (oncoprotein 18). In cancer cells, increased microtubule turnover affects cell morphology and cellular processes that rely on microtubule dynamics such as mitosis and migration. However, the molecular mechanisms deregulating modifiers of microtubule activity in human hepatocarcinogenesis are poorly understood. Based on profiling data of human hepatocellular carcinoma (HCC), we identified far upstream element binding proteins (FBPs) as significantly coregulated with stathmin. Coordinated overexpression of two FBP family members (FBP-1 and FBP-2) in 〉70% of all analyzed human HCCs significantly correlated with poor patient survival. In vitro, FBP-1 predominantly induced tumor cell proliferation, while FBP-2 primarily supported migration in different HCC cell lines. Surprisingly, reduction of FBP-2 levels was associated with elevated FBP-1 expression, suggesting a regulatory interplay of FBP family members that functionally discriminate between cell division and mobility. Expression of FBP-1 correlated with stathmin expression in HCC tissues and inhibition of FBP-1 but not of FBP-2 drastically reduced stathmin at the transcript and protein levels. In contrast, further overexpression of FBP-1 did not affect stathmin bioavailability. Accordingly, analyzing nuclear and cytoplasmic areas of HCC cells revealed that reduced FBP-1 levels affected cell morphology and were associated with a less malignant phenotype. Conclusion: The coordinated activation of FBP-1 and FBP-2 represents a novel and frequent pro-tumorigenic mechanism promoting proliferation (tumor growth) and motility (dissemination) of human liver cancer cells. FBPs promote tumor-relevant functions by at least partly employing the microtubule-destabilizing factor stathmin and represent a new potential target structure for HCC treatment. (HEPATOLOGY 2009;50:1130-1139.)
    Type of Publication: Journal article published
    PubMed ID: 19585652
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  • 9
    Keywords: CANCER ; CELLS ; EXPRESSION ; proliferation ; tumor ; carcinoma ; CELL ; Germany ; INHIBITION ; MICROSCOPY ; PATHWAY ; PATHWAYS ; HEPATOCELLULAR-CARCINOMA ; PROTEIN ; PROTEINS ; TISSUE ; TUMORS ; MICE ; ACTIVATION ; CARCINOGENESIS ; BIOLOGY ; TARGET ; hepatocellular carcinoma ; CARCINOMA CELLS ; CANCER-CELLS ; LOCALIZATION ; PHENOTYPE ; CARCINOMAS ; STRATEGIES ; TARGETS ; pathology ; DIFFERENTIAL EXPRESSION ; PATTERN ; LIGHT ; tissue microarray ; adipophilin ; FATTY-ACID SYNTHASE ; TIP47 ; STRATEGY ; PROPOSAL ; HEPATIC STEATOSIS ; lipid droplet ; PERILIPIN
    Abstract: In many human cancers, lipogenic pathways are activated; in some tumors, such as hepatocellular carcinoma, this is reflected by the presence of visible lipid droplets. Yet, the biology of steatogenesis in malignant tumors is largely unknown. We have recently shown that lipid droplet-associated proteins of the PAT-family, named after their constituents perilipin (perilipin 1), adipophilin (perilipin 2), and TIP47 (perilipin 3) are differentially expressed in hepatic steatogenesis. We have comprehensively investigated PAT-expression in neoplastic steatogenesis as well as in respective normal tissues with immunohistology and electron microscopy as well as protein biochemical and molecular biological methods. By staining for PAT-proteins, we found lipid droplet accumulation to be a frequent phenomenon of carcinoma cells. Although adipophilin and TIP47 stained almost ubiquitously the rim of lipid droplets in various tumor types, especially those with clear cell phenotype, perilipin was restricted to lipid droplets of hepatocellular adenoma and carcinoma, sebaceous adenoma and carcinoma, and lipomatous tumors. In hepatocellular carcinoma, perilipin, adipophilin, and TIP47 were coexpressed, and showed regional heterogeneity with a predominantly mutually exclusive localization pattern. In step-wise carcinogenesis, adipophilin expression correlated with the proliferation rate and was upregulated during early tumorigenesis, whereas perilipin was often lost during hepatocarcinogenesis. In conclusion, expression analysis of PAT-proteins showed that by far more carcinomas contain (PAT-positive) lipid droplets than expected by conventional light microscopy. PAT-proteins, such as perilipin, are differentially expressed in different tumor types and thus may support diagnostic considerations. Because inhibition of lipogenesis has been shown to exert antineoplastic effects, PAT-proteins may represent targets for interventive strategies. Modern Pathology (2010) 23, 480-492; doi: 10.1038/modpathol.2009.191; published online 15 January 2010
    Type of Publication: Journal article published
    PubMed ID: 20081801
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