75 research outputs found

    BAsE-Seq: a method for obtaining long viral haplotypes from short sequence reads.

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    We present a method for obtaining long haplotypes, of over 3 kb in length, using a short-read sequencer, Barcode-directed Assembly for Extra-long Sequences (BAsE-Seq). BAsE-Seq relies on transposing a template-specific barcode onto random segments of the template molecule and assembling the barcoded short reads into complete haplotypes. We applied BAsE-Seq on mixed clones of hepatitis B virus and accurately identified haplotypes occurring at frequencies greater than or equal to 0.4%, with >99.9% specificity. Applying BAsE-Seq to a clinical sample, we obtained over 9,000 viral haplotypes, which provided an unprecedented view of hepatitis B virus population structure during chronic infection. BAsE-Seq is readily applicable for monitoring quasispecies evolution in viral diseases

    Single-virion sequencing of lamivudine-treated HBV populations reveal population evolution dynamics and demographic history.

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    BACKGROUND: Viral populations are complex, dynamic, and fast evolving. The evolution of groups of closely related viruses in a competitive environment is termed quasispecies. To fully understand the role that quasispecies play in viral evolution, characterizing the trajectories of viral genotypes in an evolving population is the key. In particular, long-range haplotype information for thousands of individual viruses is critical; yet generating this information is non-trivial. Popular deep sequencing methods generate relatively short reads that do not preserve linkage information, while third generation sequencing methods have higher error rates that make detection of low frequency mutations a bioinformatics challenge. Here we applied BAsE-Seq, an Illumina-based single-virion sequencing technology, to eight samples from four chronic hepatitis B (CHB) patients - once before antiviral treatment and once after viral rebound due to resistance. RESULTS: With single-virion sequencing, we obtained 248-8796 single-virion sequences per sample, which allowed us to find evidence for both hard and soft selective sweeps. We were able to reconstruct population demographic history that was independently verified by clinically collected data. We further verified four of the samples independently through PacBio SMRT and Illumina Pooled deep sequencing. CONCLUSIONS: Overall, we showed that single-virion sequencing yields insight into viral evolution and population dynamics in an efficient and high throughput manner. We believe that single-virion sequencing is widely applicable to the study of viral evolution in the context of drug resistance and host adaptation, allows differentiation between soft or hard selective sweeps, and may be useful in the reconstruction of intra-host viral population demographic history

    Karyotype and DNA-Methylation Responses in Myelodysplastic Syndromes following Treatment with Traditional Chinese Formula Containing Arsenic

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    We have previously shown that arsenic-containing Chinese herbal formula, Qing-Huang powder capsule (containing tetraarsenic tetrasulfide, As4S4), is effective in the treatment of myelodysplastic syndrome (MDS); yet the underlined mechanisms remain unclear. In this study, using standard cytogenetic analysis (G-banded) and global DNA methylation method (ChIP-on-chip assays), we aimed to determine the effect of arsenic-containing Chinese herbal formula on karyotype status and the genomic methylation level in primarily diagnosed MDS patients. Correlation of aberrant DNA methylation and chromosome aberrations in MDS was also investigated. We found that the number of genes with aberrant DNA methylation was highest in MDS patients with normal karyotype, followed by trisomy 8 karyotype, and relatively low in patients with cytogenetic abnormalities other than trisomy 8. Treatment with arsenic-containing Chinese herbal formula had no effects on karyotype status, but resulted in a significant genome-wide demethylation. Our research uncovered a DNA demethylating activity of arsenic-containing Chinese herbal formula in the treatment of MDS

    Tolvaptan treatment improves survival of cirrhotic patients with ascites and hyponatremia

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    Background: Although tolvaptan treatment improves hyponatremia, only few studies have investigated whether tolvaptan actually benefits the survival of cirrhotic patients. This study evaluated the impact of tolvaptan on six-month survival of decompensated cirrhotic patients with and without hyponatremia. Methods: Two hundred forty-nine decompensated cirrhotic patients with or without hyponatremia were enrolled in a multicenter cohort study. Patients were divided into two groups according to receiving either tolvaptan or placebo treatment for 7-day. Subsequently, the patients were followed up for 6 months. Results: Two hundred thirty patients, including 98 with hyponatremia (tolvaptan vs. placebo: 69 vs. 29) finished the study. Tolvaptan did not alter serum sodium levels and survival outcome of decompensated cirrhotic patients without hyponatremia. However, tolvaptan treatment remarkably improved serum sodium levels and six-month survival in patients with hyponatremia. Following tolvaptan treatment, serum sodium levels were restored to normal in 63.8% of patients, whereas in patients receiving placebo, only 36.2% showed the same effect (P < 0.05). Compared to a six-month survival rate of 68.97% in patients receiving placebo, the survival rate in tolvapatan-treated patients was 89.94% (P < 0.05). Furthermore, six-month survival rate in the tolvaptan-treated hyponatremia patients with resolved serum sodium was 81.32%, whereas the survival in those with unresolved serum sodium was only 24% (P < 0.05). Conclusions: Tolvaptan improves short term survival in most decompensated cirrhotic hyponatremia patients with resolved serum sodium. Trials registration: Clinical trial one: ClinicalTrials.gov ID: NCT00664014 , Registered on April 14, 2008. Clinical trial two: ClinicalTrials.gov ID: NCT01349335 , Registered on March 5, 2010. Clinical trial three: ClinicalTrials.gov ID: NCT01349348 , Registered on May 4, 2011

    IGFBP-rP1, a potential molecule associated with colon cancer differentiation

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    <p>Abstract</p> <p>Background</p> <p>In our previous studies, we have demonstrated that insulin-like growth factor binding protein-related protein1 (IGFBP-rP1) played its potential tumor suppressor role in colon cancer cells through apoptosis and senescence induction. In this study, we will further uncover the role of IGFBP-rP1 in colon cancer differentiation and a possible mechanism by revealing responsible genes.</p> <p>Results</p> <p>In normal colon epithelium, immunohistochemistry staining detected a gradient IGFBP-rP1 expression along the axis of the crypt. IGFBP-rP1 strongly expressed in the differentiated cells at the surface of the colon epithelium, while weakly expressed at the crypt base. In colon cancer tissues, the expression of IGFBP-rP1 correlated positively with the differentiation status. IGFBP-rP1 strongly expressed in low grade colorectal carcinoma and weakly expressed in high grade colorectal carcinoma. In vitro, transfection of PcDNA3.1(IGFBP-rP1) into RKO, SW620 and CW2 cells induced a more pronounced anterior-posterior polarity morphology, accompanied by upregulation with alkaline phosphatase (AKP) activity. Upregulation of carcino-embryonic antigen (CEA) was also observed in SW620 and CW2 transfectants. The addition of IGFBP-rP1 protein into the medium could mimic most but not all effects of IGFBP-rP1 cDNA transfection. Seventy-eight reproducibly differentially expressed genes were detected in PcDNA3.1(IGFBP-rP1)-RKO transfectants, using Affymetrix 133 plus 2.0 expression chip platform. Directed Acyclic Graph (DAG) of the enriched GO categories demonstrated that differential expression of the enzyme regulator activity genes together with cytoskeleton and actin binding genes were significant. IGFBP-rP1 could upreguate Transgelin (TAGLN), downregulate SRY (sex determining region Y)-box 9(campomelic dysplasia, autosomal sex-reversal) (SOX9), insulin receptor substrate 1(IRS1), cyclin-dependent kinase inhibitor 2B (p15, inhibits CDK4) (CDKN2B), amphiregulin(schwannoma-derived growth factor) (AREG) and immediate early response 5-like(IER5L) in RKO, SW620 and CW2 colon cancer cells, verified by Real time Reverse Transcription Polymerase Chain Reaction (rtRT-PCR). During sodium butyrate-induced Caco2 cell differentiation, IGFBP-rP1 was upregulated and the expression showed significant correlation with the AKP activity. The downregulation of IRS1 and SOX9 were also induced by sodium butyrate.</p> <p>Conclusion</p> <p>IGFBP-rP1 was a potential key molecule associated with colon cancer differentiation. Downregulation of IRS1 and SOX9 may the possible key downstream genes involved in the process.</p

    Extensive Promoter-Centered Chromatin Interactions Provide a Topological Basis for Transcription Regulation

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    Higher-order chromosomal organization for transcription regulation is poorly understood in eukaryotes. Using genome-wide Chromatin Interaction Analysis with Paired-End-Tag sequencing (ChIAPET), we mapped long-range chromatin interactions associated with RNA polymerase II in human cells and uncovered widespread promoter-centered intragenic, extragenic, and intergenic interactions. These interactions further aggregated into higher-order clusters, wherein proximal and distal genes were engaged through promoter-promoter interactions. Most genes with promoter-promoter interactions were active and transcribed cooperatively, and some interacting promoters could influence each other implying combinatorial complexity of transcriptional controls. Comparative analyses of different cell lines showed that cell-specific chromatin interactions could provide structural frameworks for cell-specific transcription, and suggested significant enrichment of enhancer-promoter interactions for cell-specific functions. Furthermore, genetically-identified disease-associated noncoding elements were found to be spatially engaged with corresponding genes through long-range interactions. Overall, our study provides insights into transcription regulation by three-dimensional chromatin interactions for both housekeeping and cell-specific genes in human cells

    The evaluation of implantable venous access ports in patients with cancer

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    Cancer itself is relatively hidden. Most cancers have a long incubation period. Chemotherapy drugs cause great damage to blood vessels. Many tumor patients are also accompanied by diabetes, hypertension, vascular embolism and other diseases. The vascular condition is generally poor, so veins appear during puncture and treatment. The probability of inflammation increases significantly. If the chemotherapeutic drugs extravasate, it will cause local tissue necrosis, reduce the quality of life of patients, and increase the economic burden of patients. Implantable venous port access (IVPA) have the advantages of avoiding repeated puncture, less irritation, safe infusion, and long use time, and are widely used. - Methods used: Descriptive literature review methods - Key results: Through these articles, we knew that how to evaluate the IVAP site and how to prevent infections in IVAP site in patients with cancer. - Analysis of the results: There are 5 points to evaluate the IVAP site. The most important point for preventing infection is strict aseptic care of the puncture site. -Conclusions and recommendations: Infection remains the most common complication of the venous access system in cancer patients. Changing the access needle and clear dressing every 7 days is a safe, cost-effective, and efficient way to disinfect and keep the exit site clean. Keywords: Evaluation, Implantable venous access ports, Cancer

    Astragalus Salvia Granules to Benefit the Qi (Qishen Yiqi Keli) protects H9C2 cardiomyocytes by suppressing oxidative stress

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    Objective: To investigate the effects of Qishen Yiqi Keli (QSYQ; Astragalus Salvia Granules to Benefit the Qi) on ROS scavenging and inhibition of NADPH oxidase in an effort to identify new natural antioxidants. Methods: A total of 23 representative components in QSYQ were investigated, their effects on hydrogen peroxide induced ROS were assayed by dichlorofluorescein assay. Lucigenin chemiluminescence was adopted to test the effect on NADPH oxidase activity in H9C2 cardiomyocyte cells, and pyrogallol autoxidation was adopted to test the superoxide scavenging capacity. Results: Nine compounds in QSYQ could significantly inhibited H2O2-induced ROS increase compared with the model group (P < .05), including tanshinone I, salvianolic acid A, danshinone IIA, and cryptotanshinone from salvia root, luteolin from salvia root, harpagoside, harpagide, and angoroside C from scrophularia root. Nine compounds in QSYQ could significantly inhibited the production of ·−O2− in H9C2 cell. Tanshinone I showed a lowest IC50 value 0.07 μM, the other including salvianolic acid A, cryptotanshinone, and salvianolic acid B, luteolin, isochlorogenic acid C, astragaloside IV, and glycyrrhetinic acid. Licochalcone A inhibited the autoxidation of pyrogallol at a low concentration, and tanshinone I showed no significant inhibitory effect from 2 μM to 20 μM. Conclusion: QSYQ had significant effects on ROS scavenging and inhibition of NADPH oxidase. Tanshinone I and salvianolic acid A are potential NADPH oxidase inhibitors
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