75 research outputs found

    High-yield antibody production using targeted integration and engineering CHO host

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    To identify the high expression sites in the CHO cells, we employed NGS to analyze the integration sites of a high producing cell line (titer \u3e 3g/L). The pair-end reads with one read mapped to the vector and the other read mapped to the CHO reference genome are extracted to identify the integration sites. To test the expression activity of the integration sites, we employed CRISPR/Cas9 to specifically integrate the antibody gene into CHO genome for expression. Our data showed 4 integration sites are in the high producing cell line. Among the 4 integration site, one integration site was tested by CRISPR/Cas9 for target integration of antibody gene for expression. The target integrated cell pool present higher expression level (130 mg/L/copy) and less copy number when compared other integration sites. Through single-copy integration method, we can also achieve 60-150 mg/L/copy in a batch culture. About 80% of the single-copy cell clones were stable at generation 60. We have also applied the CHO-specific microarray transcriptomics technology to identify genes that contribute to high productivity. Transfection of our proprietary dual promoter vector J 1.0 resulting in 1.65 to 2.4 fold increase in the expression in engineered CHO DXB11 host. Through fed-batch process development, 3 – 5 g/L mAb productivity can be achieved through targeted integration and engineered CHO host

    Development of high-producing CHO cell lines through target-designed strategy

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    Productivity and stability are critical for the protein drug producing cell lines for manufacturing. Given that the integration sites of gene of interest (GOI) could contribute remarkable effect on the productivity and stability of GOI expression, we intended to develop a targeting-designed approach to generate the high-producing cell lines in a time-saving and less labor-intensive method through targeting the active and stable regions. To identify the active and stable regions located in CHO genome, two approaches were applied in our experiments. Firstly, the integration sites of GOI in cell clones developed by random integration were identified by whole genome sequencing. Secondly, we developed transposon-mediated low copy integration to discover novel active region located in CHO genome. It is interesting that the productivity per integrated GOI in cell clones developed by transposon system was more than two times to that in cell clones developed by random integration (random integration: 20-40 mg/L/copy; transposon-mediated integration: 40-140mg/L/copy). In addition, about 80% of cell clones developed by transposon system maintained the stability of antibody titer after culturing for 60 generations. These results implied that the potential active and stable integration region in the cell clones developed by transposon system. The identified integration regions could be applied for target integration. In order to verify the expression activity and stability of the integration sites, we employed CRISPR/Cas9 to specifically integrate the antibody gene into CHO genome for expression. Our data showed the cell pool generated by knock-in of expression vector into the IS1 integration site present higher expression titer than cell pools generated by integration into other sites or random integration. We further cultured the single cell clones derived from this cell pool by Clonepix and limiting dilution. These single cell clones have high expression titer ranging from 254 to 804 mg/L in batch culture of after 6 Days. A single cell clone(376 mg/L in batch culture) can reached 2 g/L in fed-batch culture. The stability analysis showed this clone maintain stable expression of GOI after 60 generation. Here, we demonstrated the generation of stable cell line with high protein expression by CRISPR/Cas9 mediated target integration. This approach will cost less time and labor than traditional method

    Modified Weekly Cisplatin-Based Chemotherapy Is Acceptable in Postoperative Concurrent Chemoradiotherapy for Locally Advanced Head and Neck Cancer

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    Background. Triweekly cisplatin-based postoperative concurrent chemoradiotherapy (CCRT) has high intolerance and toxicities in locally advanced head and neck cancer (LAHNC). We evaluated the effect of a modified weekly cisplatin-based chemotherapy in postoperative CCRT. Methods. A total of 117 patients with LAHNC were enrolled between December 2007 and December 2012. Survival, compliance/adverse events, and independent prognostic factors were analyzed. Results. Median follow-up time was 30.0 (3.1–73.0) months. Most patients completed the entire course of postoperative CCRT (radiotherapy ≄ 60 Gy, 94.9%; ≄6 times weekly chemotherapy, 75.2%). Only 17.1% patients required hospital admission. The most common adverse effect was grade 3/4 mucositis (28.2%). No patient died due to protocol-related adverse effects. Multivariate analysis revealed the following independent prognostic factors: oropharyngeal cancer, extracapsular spread, and total radiation dose. Two-year progression-free survival and overall survival rates were 70.9% and 79.5%, respectively. Conclusion. Modified weekly cisplatin-based chemotherapy is an acceptable regimen in postoperative CCRT for LAHNC

    Evaluation of prognostic factors and the role of chemotherapy in unfavorable carcinoma of unknown primary site: a 10-year cohort study

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    <p>Abstract</p> <p>Background</p> <p>Carcinoma of unknown primary site (CUP) has a poor prognosis and the prognostic factors in these patients are not well established. Furthermore, there are no selection criteria for patients who should benefit from chemotherapy.</p> <p>Methods</p> <p>The medical records of 179 CUP patients who were treated at Taipei Veterans General Hospital from 2000 to 2009 were reviewed. Factors associated with survival were determined by Kaplan-Meier analysis. Differences between the groups with and without palliative chemotherapy were analyzed.</p> <p>Results</p> <p>Univariate analysis revealed multiple prognostic factors, including performance status, lung metastasis, number of metastatic organs, serum albumin, corrected serum calcium, lactate dehydrogenase (LDH), sodium, and cholesterol levels, palliative chemotherapy, and white blood cell and lymphocyte counts. Multivariate analysis showed that performance status < 2, serum albumin level ≄ 3.5 g/dl, corrected serum calcium level < 10.7 mg/dl, single metastatic organ, and palliative chemotherapy were independent factors of better prognosis. Patients with better performance status, higher serum albumin, and lower serum LDH levels had significantly greater benefit from palliative chemotherapy.</p> <p>Conclusions</p> <p>Certain patients with unfavorable CUP will have better survival. Identification of patients with unfavorable CUP who could benefit from palliative chemotherapy warrants future prospective studies.</p

    International Consensus Statement on Rhinology and Allergy: Rhinosinusitis

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    Background: The 5 years since the publication of the first International Consensus Statement on Allergy and Rhinology: Rhinosinusitis (ICAR‐RS) has witnessed foundational progress in our understanding and treatment of rhinologic disease. These advances are reflected within the more than 40 new topics covered within the ICAR‐RS‐2021 as well as updates to the original 140 topics. This executive summary consolidates the evidence‐based findings of the document. Methods: ICAR‐RS presents over 180 topics in the forms of evidence‐based reviews with recommendations (EBRRs), evidence‐based reviews, and literature reviews. The highest grade structured recommendations of the EBRR sections are summarized in this executive summary. Results: ICAR‐RS‐2021 covers 22 topics regarding the medical management of RS, which are grade A/B and are presented in the executive summary. Additionally, 4 topics regarding the surgical management of RS are grade A/B and are presented in the executive summary. Finally, a comprehensive evidence‐based management algorithm is provided. Conclusion: This ICAR‐RS‐2021 executive summary provides a compilation of the evidence‐based recommendations for medical and surgical treatment of the most common forms of RS

    Reduction of the Electrode Overpotential of the Oxygen Evolution Reaction by Electrode Surface Modification

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    Metal–air batteries exhibit high potential for grid-scale energy storage because of their high theoretical energy density, their abundance in the earth’s crust, and their low cost. In these batteries, the oxygen evolution reaction (OER) occurs on the air electrode during charging. This study proposes a method for improving the OER electrode performance. The method involves sequentially depositing a Ni underlayer, Sn whiskers, and a Ni protection layer on the metal mesh. Small and uniform gas bubbles form on the Ni/Sn/Ni mesh, leading to low overpotential and a decrease in the overall resistance of the OER electrode. The results of a simulated life cycle test indicate that the Ni/Sn/Ni mesh has a life cycle longer than 1,300 cycles when it is used as the OER electrode in 6 M KOH

    Structured Populations of Critically Endangered Yellow Water Lily (Nuphar shimadai Hayata, Nymphaeaceae)

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    Yellow water lily (Nuphar shimadai Hayata) is a critically endangered species in Taiwan. Here, we examined genetic structures of four extant populations, WP, GPa, GPb and GPn, using 39 simple sequence repeat (SSR) markers. Positive genetic correlation was observed within 50 m, beyond which no correlation was detected due to isolation by distance according to Mantel correlogram. This suggests a significant genetic structuring of the species. Besides, multilocus genotype (MLG) analysis revealed that GPa was a panmictic population and the species&rsquo; putative center of origin. Genetic exchange was observed between GPa and GPb populations, which likely resulted from their geographic proximity. Nevertheless, there was a strong asymmetric migration detected from GPa to WP, but a recent genetic barrier prevented dispersal further northward (WP). Geneland estimated the best number of clusters as K = 2, where WP distinctly separated from the rest of the populations. In STRUCTURE output of K = 3, a third cluster was abundant only in WP. We suggest to consider GPn and WP as separate conservation units, being far from GPa. There is indeed a need to investigate these populations; as predicted, Ne = 1.6 to 3.0 is considered low and that may put the species at risk of extinction

    Characteristics of fucose-containing polysaccharides from submerged fermentation of Agaricus blazei Murill

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    Fucose is one of important residues of recognition pattern for many immune cells. In this study, we characterized bioactive fucose-containing acidic polysaccharides from submerged fermentation of Agaricus blazei Murill. We obtained the polysaccharides through a cell-based activity-guided strategy, and used carbohydrate recognition monoclonal antibodies based Enzyme-Linked Immuno Sorbent Assay (ELISA) along with methylation and NMR analyses to investigate the structural characteristics of the polysaccharides. The polysaccharides had Mw of 3.5 × 105 Da. The major sugars were l-fucose, l-arabinose, d-galactose, d-xylose, and d-galacturonic acid in the molar ratio of 6.4, 15.5, 28.5, 14.7, and 25.0% with a small amount of d-glucose, d-mannose, l-rhamnose, and d-glucuronic acid. Results indicated that the bioactive polysaccharides consisted of a (1,4)-Galp and (1,4)-GalAp back bone; (1,2)-Xyl and (1,2)-Rha might also comprise backbone or constitute side chain; linkage (1,5)-Ara and terminal fucosyl residues were also involved in the polysaccharides. Regarding bioactivity, removal of the terminal l-fucosyl residues reduced the TNF-α cytokine stimulating activity of the polysaccharides in a RAW 264.7 macrophage cell-line test, whereas NF-ÎșB and TLR4 affected the polysaccharide-induced TNF-α production. Keywords: Agaricus blazei Murill, Acidic polysaccharide, Fucose, Galactan, TNF-α stimulatio
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