184 research outputs found

    QCD corrections to J/ψJ/\psi plus Z0Z^0-boson production at the LHC

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    The J/ψ+Z0J/\psi+Z^0 associated production at the LHC is an important process in investigating the color-octet mechanism of non-relativistic QCD in describing the processes involving heavy quarkonium. We calculate the next-to-leading order (NLO) QCD corrections to the J/ψ+Z0J/\psi +Z^0 associated production at the LHC within the factorization formalism of nonrelativistic QCD, and provide the theoretical predictions for the distribution of the J/ψJ/\psi transverse momentum. Our results show that the differential cross section at the leading-order is significantly enhanced by the NLO QCD corrections. We conclude that the LHC has the potential to verify the color-octet mechanism by measuring the J/ψ+Z0J/\psi+Z^0 production events.Comment: 14 page revtex, 5 eps figures, to appear in JHEP. fig5 and the corresponding analysis are correcte

    Micro-Environmental Mechanical Stress Controls Tumor Spheroid Size and Morphology by Suppressing Proliferation and Inducing Apoptosis in Cancer Cells

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    Compressive mechanical stress produced during growth in a confining matrix limits the size of tumor spheroids, but little is known about the dynamics of stress accumulation, how the stress affects cancer cell phenotype, or the molecular pathways involved.We co-embedded single cancer cells with fluorescent micro-beads in agarose gels and, using confocal microscopy, recorded the 3D distribution of micro-beads surrounding growing spheroids. The change in micro-bead density was then converted to strain in the gel, from which we estimated the spatial distribution of compressive stress around the spheroids. We found a strong correlation between the peri-spheroid solid stress distribution and spheroid shape, a result of the suppression of cell proliferation and induction of apoptotic cell death in regions of high mechanical stress. By compressing spheroids consisting of cancer cells overexpressing anti-apoptotic genes, we demonstrate that mechanical stress-induced apoptosis occurs via the mitochondrial pathway.Our results provide detailed, quantitative insight into the role of micro-environmental mechanical stress in tumor spheroid growth dynamics, and suggest how tumors grow in confined locations where the level of solid stress becomes high. An important implication is that apoptosis via the mitochondrial pathway, induced by compressive stress, may be involved in tumor dormancy, in which tumor growth is held in check by a balance of apoptosis and proliferation

    Genetic Variation in the EGFR Gene and the Risk of Glioma in a Chinese Han Population

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    Previous studies have shown that regulation of the epidermal growth factor gene (EGFR) pathway plays a role in glioma progression. Certain genotypes of the EGFR gene may be related to increased glioblastoma risk, indicating that germ line EGFR polymorphisms may have implications in carcinogenesis. To examine whether and how variants in the EGFR gene contribute to glioma susceptibility, we evaluated nine tagging single-nucleotide polymorphisms (tSNPs) of the EGFR gene in a case–control study from Xi'an city of China (301 cases, 302 controls). EGFR SNP associations analyses were performed using SPSS 16.0 statistical packages, PLINK software, Haploview software package (version 4.2) and SHEsis software platform. We identified two susceptibility tSNPs in the EGFR gene that were potentially associated with an increased risk of glioma (rs730437, p = 0.016; OR: 1.32; 95%CI: 1.05–1.66 and rs1468727, p = 0.008; OR: 1.31; 95%CI: 1.04–1.65). However, after a strict Bonferroni correction analysis was applied, the significance level of the association between EGFR tSNPs and risk of glioma was attenuated. We observed a protective effect of haplotype “AATT” of the EGFR gene, which was associated with a 29% reduction in the risk of developing glioma, while haplotype “CGTC” increased the risk of developing glioma by 36%. Our results, combined with previous studies, suggested an association between the EGFR gene and glioma development

    Integrated syphilis/HIV screening in China: a qualitative analysis

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    <p>Abstract</p> <p>Background</p> <p>The last decade has seen enormous advances in HIV treatment and care, but how to implement scaled up HIV testing, prevention, and treatment in low-income areas still presents a formidable public health challenge. South China faces expanding syphilis and sexually transmitted HIV epidemics, but health systems characteristics important for scaling up syphilis and HIV testing have not been defined.</p> <p>Methods</p> <p>A purposive sample to ensure public, private, and public-private hybrid STI clinic inclusion was selected in a South China city. Eight key informant interviews were conducted with the STI clinic manager, followed by eight focus group discussions with physicians. Data collection relied on a semi-structured format that included questions in each of the following domains: 1) clinical facilities; 2) laboratory capacity with a focus on syphilis/HIV diagnosis; 3) clinic personnel; 4) physical space with a focus on locations to disclose confidential results; 5) financial support.</p> <p>Results</p> <p>Public STI clinics had free syphilis testing/treatment and laboratory facilities to perform essential syphilis and HIV tests. However, despite serving a large number of STI patients, private STI clinics lacked nontreponemal syphilis testing, HIV testing, and had fewer connections to the public health infrastructure. Formally trained assistant physicians were 2.5 times as common as physicians at STI clinics. Only one of the 8 sites had onsite voluntary counseling and testing (VCT) services available.</p> <p>Conclusion</p> <p>These STI case studies reveal the potential for expanding integrated syphilis/HIV services at public STI clinics in China. More health services research is needed to guide scale-up of syphilis/HIV testing in China.</p

    Pathway-Based Association Analyses Identified TRAIL Pathway for Osteoporotic Fractures

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    ) pathway were associated with bone metabolism. This study aims to verify the potential association between hip OF and TRAIL pathway.Using genome-wide genotype data from Affymetrix 500 K SNP arrays, we performed novel pathway-based association analyses for hip OF in 700 elderly Chinese Han subjects (350 with hip OF and 350 healthy matched controls).) of the pathway had minor alleles (A) that are associated with an increased risk of hip OF, with the ORs (odds ratios) of 16.51 (95%CI:3.83–71.24) and 1.37 (95%CI:1.08–1.74), respectively.Our study supports the potential role of the TRAIL pathway in the pathogenesis of hip OF in Chinese Han population. Further functional study of this pathway will be pursued to determine the mechanism by which it confers risk to hip OF

    Genomic variation in myeloma: design, content, and initial application of the Bank On A Cure SNP Panel to detect associations with progression-free survival

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    <p>Abstract</p> <p>Background</p> <p>We have engaged in an international program designated the <it>Bank On A Cure</it>, which has established DNA banks from multiple cooperative and institutional clinical trials, and a platform for examining the association of genetic variations with disease risk and outcomes in multiple myeloma.</p> <p>We describe the development and content of a novel custom SNP panel that contains 3404 SNPs in 983 genes, representing cellular functions and pathways that may influence disease severity at diagnosis, toxicity, progression or other treatment outcomes. A systematic search of national databases was used to identify non-synonymous coding SNPs and SNPs within transcriptional regulatory regions. To explore SNP associations with PFS we compared SNP profiles of short term (less than 1 year, <it>n </it>= 70) versus long term progression-free survivors (greater than 3 years, <it>n </it>= 73) in two phase III clinical trials.</p> <p>Results</p> <p>Quality controls were established, demonstrating an accurate and robust screening panel for genetic variations, and some initial racial comparisons of allelic variation were done. A variety of analytical approaches, including machine learning tools for data mining and recursive partitioning analyses, demonstrated predictive value of the SNP panel in survival. While the entire SNP panel showed genotype predictive association with PFS, some SNP subsets were identified within drug response, cellular signaling and cell cycle genes.</p> <p>Conclusion</p> <p>A targeted gene approach was undertaken to develop an SNP panel that can test for associations with clinical outcomes in myeloma. The initial analysis provided some predictive power, demonstrating that genetic variations in the myeloma patient population may influence PFS.</p

    Leaderless genes in bacteria: clue to the evolution of translation initiation mechanisms in prokaryotes

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    <p>Abstract</p> <p>Background</p> <p>Shine-Dalgarno (SD) signal has long been viewed as the dominant translation initiation signal in prokaryotes. Recently, leaderless genes, which lack 5'-untranslated regions (5'-UTR) on their mRNAs, have been shown abundant in archaea. However, current large-scale <it>in silico </it>analyses on initiation mechanisms in bacteria are mainly based on the SD-led initiation way, other than the leaderless one. The study of leaderless genes in bacteria remains open, which causes uncertain understanding of translation initiation mechanisms for prokaryotes.</p> <p>Results</p> <p>Here, we study signals in translation initiation regions of all genes over 953 bacterial and 72 archaeal genomes, then make an effort to construct an evolutionary scenario in view of leaderless genes in bacteria. With an algorithm designed to identify multi-signal in upstream regions of genes for a genome, we classify all genes into SD-led, TA-led and atypical genes according to the category of the most probable signal in their upstream sequences. Particularly, occurrence of TA-like signals about 10 bp upstream to translation initiation site (TIS) in bacteria most probably means leaderless genes.</p> <p>Conclusions</p> <p>Our analysis reveals that leaderless genes are totally widespread, although not dominant, in a variety of bacteria. Especially for <it>Actinobacteria </it>and <it>Deinococcus-Thermus</it>, more than twenty percent of genes are leaderless. Analyzed in closely related bacterial genomes, our results imply that the change of translation initiation mechanisms, which happens between the genes deriving from a common ancestor, is linearly dependent on the phylogenetic relationship. Analysis on the macroevolution of leaderless genes further shows that the proportion of leaderless genes in bacteria has a decreasing trend in evolution.</p

    Immunotherapy of pediatric brain tumor patients should include an immunoprevention strategy: a medical hypothesis paper

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    Adults diagnosed with Glioblastoma multiforme (GBM) are frequently faced with a 7% chance of surviving 2 years compared with pediatric patients with GBM who have a 26% survival rate. Our recent screen of possible glioma-associated antigen precursor protein (TAPP) profiles displayed from different types of pediatric brain tumors showed that pediatric patients contained a subset of the tumor antigens displayed by adult GBM patients. Adult GBM possess at least 27 tumor antigens that can potentially stimulate T cell immune responses, suggesting that these tumors are quite antigenic. In contrast, pediatric brain tumors only expressed nine tumor antigens with mRNA levels that were equivalent to those displayed by adult GBM. These tumor-associated antigens could be used as possible targets of therapeutic immunization for pediatric brain cancer patients. Children have developing immune systems that peak at puberty. An immune response mounted by these pediatric patients might account for their extended life spans, even though the pediatric brain tumors express far fewer total tumor-associated antigens. Here we present a hypothesis that pediatric brain tumor patients might be the best patients to show that immunotherapy can be used to successfully treat established cancers. We speculate that immunotherapy should include a panel of tumor antigens that might prevent the out-growth of more malignant tumor cells and thereby prevent the brain tumor relapse. Thus, pediatric brain tumor patients might provide an opportunity to prove the concept of immunoprevention

    Identification of Piwil2-Like (PL2L) Proteins that Promote Tumorigenesis

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    PIWIL2, a member of PIWI/AGO gene family, is expressed in the germline stem cells (GSCs) of testis for gametogenesis but not in adult somatic and stem cells. It has been implicated to play an important role in tumor development. We have previously reported that precancerous stem cells (pCSCs) constitutively express Piwil2 transcripts to promote their proliferation. Here we show that these transcripts de facto represent Piwil2-like (PL2L) proteins. We have identified several PL2L proteins including PL2L80, PL2L60, PL2L50 and PL2L40, using combined methods of Gene-Exon-Mapping Reverse Transcription Polymerase Chain Reaction (GEM RT-PCR), bioinformatics and a group of novel monoclonal antibodies. Among them, PL2L60 rather than Piwil2 and other PL2L proteins is predominantly expressed in various types of human and mouse tumor cells. It promotes tumor cell survival and proliferation in vitro through up-regulation of Stat3 and Bcl2 gene expressions, the cell cycle entry from G0/1 into S-phase, and the nuclear expression of NF-κB, which contribute to the tumorigenicity of tumor cells in vivo. Consistently, PL2L proteins rather than Piwil2 are predominantly expressed in the cytoplasm or cytoplasm and nucleus of euchromatin-enriched tumor cells in human primary and metastatic cancers, such as breast and cervical cancers. Moreover, nuclear PL2L proteins are always co-expressed with nuclear NF-κB. These results reveal that PL2L60 can coordinate with NF-κB to promote tumorigenesis and might mediate a common pathway for tumor development without tissue restriction. The identification of PL2L proteins provides a novel insight into the mechanisms of cancer development as well as a novel bridge linking cancer diagnostics and anticancer drug development

    MiR-218 Inhibits Invasion and Metastasis of Gastric Cancer by Targeting the Robo1 Receptor

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    MicroRNAs play key roles in tumor metastasis. Here, we describe the regulation and function of miR-218 in gastric cancer (GC) metastasis. miR-218 expression is decreased along with the expression of one of its host genes, Slit3 in metastatic GC. However, Robo1, one of several Slit receptors, is negatively regulated by miR-218, thus establishing a negative feedback loop. Decreased miR-218 levels eliminate Robo1 repression, which activates the Slit-Robo1 pathway through the interaction between Robo1 and Slit2, thus triggering tumor metastasis. The restoration of miR-218 suppresses Robo1 expression and inhibits tumor cell invasion and metastasis in vitro and in vivo. Taken together, our results describe a Slit-miR-218-Robo1 regulatory circuit whose disruption may contribute to GC metastasis. Targeting miR-218 may provide a strategy for blocking tumor metastasis
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