48 results on '"Clark Chen"'
Search Results
2. National Trends in Total Hip Arthroplasty Bearing Surface Usage in Extremely Young Patients Between 2006 and 2016
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Christopher M. Hart, MD, Clark Chen, MD, Peter P. Hsiue, MD, Reza Farshchi, BS, Mauricio Silva, MD, Erik Zeegen, MD, Rachel Thompson, MD, and Alexandra Stavrakis, MD
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Total hip arthroplasty ,Pediatric ,Bearing surface trends ,Orthopedic surgery ,RD701-811 - Abstract
Background: Long-term implant durability is a key concern when considering total hip arthroplasty (THA) in young patients. The ideal bearing surface used in these patients remains unknown. The purpose of this study was to analyze trends in THA bearing surface use from 2006 to 2016 using a large, pediatric national database. Methods: This was a retrospective review from January 1, 2006, to December 31, 2016, using the Kids’ Inpatient Database. International Classification of Diseases, 9th revision and 10th revision codes were used to identify patients who underwent THA and create cohorts based on bearing surfaces: metal-on-metal, metal-on-polyethylene, ceramic-on-polyethylene (CoP), and ceramic-on-ceramic (CoC). Annual utilization of each bearing surface and associated patient and hospital demographics were analyzed. Results: A total of 1004 THAs were identified during the 11-year study period. The annual number of THAs performed increased by 169% from 2006 to 2016. The mean patient age was 17.1 years. The most prevalent bearing surface used in 2006 was CoC (37.3%), metal-on-metal (31.8%) in 2009, and CoP in 2012 and 2016 (50.6% and 64.8%, respectively). From 2006 to 2016, utilization of CoP increased from 5.0% to 64.8%, representing a 1196% increase over the study period. Conclusions: The number of THAs performed in pediatric patients is increasing significantly. Although CoC was previously the most commonly used bearing surface in this patient population, CoP is currently the most common. Further investigation is needed to determine whether bearing longevity and clinical outcomes with CoP are superior to other bearing surfaces.
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- 2021
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3. 169 Off-the-shelf, engineered iPSC-derived NK cells mediate potent cytotoxic activity against primary glioblastoma cells and promote durable long-term survival in vivo
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Jeffrey Miller, Tom Lee, Ryan Bjordahl, Frank Cichocki, Jianfang Ning, Zachary Davis, Katie Tuininga, Hongbo Wang, Paul Rogers, Moyar Ge, Bob Valamehr, and Clark Chen
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Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,RC254-282 - Published
- 2021
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4. 155 iPSC-derived NK cells mediate robust anti-tumor activity against glioblastoma
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Jeffrey Miller, Tom Lee, Ryan Bjordahl, Frank Cichocki, Jianfang Ning, Zachary Davis, Katie Tuininga, Hongbo Wang, Paul Rogers, Moyar Ge, Bob Valamehr, and Clark Chen
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Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,RC254-282 - Published
- 2020
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5. Postoperative complications with cryotherapy in bone tumors
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Clark Chen, John Garlich, Katie Vincent, and Earl Brien
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Cryotherapy ,Cryoablation ,Benign aggressive bone tumor ,Liquid nitrogen ,Complication ,Curettage ,Diseases of the musculoskeletal system ,RC925-935 ,Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,RC254-282 - Abstract
The technique of cryosurgery has been used to control local recurrence in a variety of benign and malignant bone tumors. Early studies revealed significant complication rates (25%) that included fracture, infection, and soft tissue injury. Our method of cryosurgery has yielded excellent tumor control with improved complication rates. The objective of this study is to determine the characteristics of postoperative complications after pouring liquid nitrogen into curettaged bone defects, and to review our current indications and surgical technique in bone tumor management. We reviewed charts in over 200 patients who received cryoablation for bone tumors from 1994 to 2015. Imaging studies were evaluated in all patients diagnosed with a complication. All patients receiving cryotherapy had soft tissue management intraoperatively that included warm saline directed to the structures. Liquid nitrogen was poured into the bone defect and in some cases, additional spraying with a cryogun into the defect was performed. The majority of cryotherapy was used in cases of active or aggressive benign tumors. Our low complication rate of 2.34% included 1 post-operative fracture, 3 infection, and 1 paraesthesia. Bone graft or cementation was used in the majority of patients, all of which fully incorporated. Cryoablation is an excellent from of adjuvant therapy for active and aggressive benign tumors and may be used in malignant tumors as well. Soft tissue protection is critical to avoid skin necrosis and wound breakdown. We recommend the use of cryotherapy in active and aggressive bone tumors as an adjuvant treatment prior to bone grafting or cementation.
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- 2017
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6. Glioblastoma stem cell-derived exosomes induce M2 macrophages and PD-L1 expression on human monocytes
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Konrad Gabrusiewicz, Xu Li, Jun Wei, Yuuri Hashimoto, Anantha L. Marisetty, Martina Ott, Fei Wang, David Hawke, John Yu, Luke M. Healy, Anwar Hossain, Johnny C. Akers, Sourindra N. Maiti, Shinji Yamashita, Yuzaburo Shimizu, Kenneth Dunner, M. Anna Zal, Jared K. Burks, Joy Gumin, Felix Nwajei, Aras Rezavanian, Shouhao Zhou, Ganesh Rao, Raymond Sawaya, Gregory N. Fuller, Jason T. Huse, Jack P. Antel, Shulin Li, Laurence Cooper, Erik P. Sulman, Clark Chen, Changiz Geula, Raghu Kalluri, Tomasz Zal, and Amy B. Heimberger
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cancer stem cells ,exosome ,glioblastoma ,immune cells ,stat3 ,pd-l1 ,Immunologic diseases. Allergy ,RC581-607 ,Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,RC254-282 - Abstract
Exosomes can mediate a dynamic method of communication between malignancies, including those sequestered in the central nervous system and the immune system. We sought to determine whether exosomes from glioblastoma (GBM)-derived stem cells (GSCs) can induce immunosuppression. We report that GSC-derived exosomes (GDEs) have a predilection for monocytes, the precursor to macrophages. The GDEs traverse the monocyte cytoplasm, cause a reorganization of the actin cytoskeleton, and skew monocytes toward the immune suppresive M2 phenotype, including programmed death-ligand 1 (PD-L1) expression. Mass spectrometry analysis demonstrated that the GDEs contain a variety of components, including members of the signal transducer and activator of transcription 3 (STAT3) pathway that functionally mediate this immune suppressive switch. Western blot analysis revealed that upregulation of PD-L1 in GSC exosome-treated monocytes and GBM-patient-infiltrating CD14+ cells predominantly correlates with increased phosphorylation of STAT3, and in some cases, with phosphorylated p70S6 kinase and Erk1/2. Cumulatively, these data indicate that GDEs are secreted GBM-released factors that are potent modulators of the GBM-associated immunosuppressive microenvironment.
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- 2018
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7. A Deep Learning Approach for Placing Magnetic Resonance Spectroscopy Voxels in Brain Tumors.
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Sangyoon Lee, Francesca Branzoli, Thanh Nguyen, Ovidiu C. Andronesi, Alexander Lin, Roberto Liserre, Gerd Melkus, Clark Chen, Malgorzata Marjanska, and Patrick J. Bolan
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- 2024
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8. Differential expression of miR-145 in children with Kawasaki disease.
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Chisato Shimizu, Jihoon Kim, Petra Stepanowsky, Christine Trinh, Hubert D Lau, Johnny C Akers, Clark Chen, John T Kanegaye, Adriana Tremoulet, Lucila Ohno-Machado, and Jane C Burns
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Medicine ,Science - Abstract
Kawasaki disease is an acute, self-limited vasculitis of childhood that can result in structural damage to the coronary arteries. Previous studies have implicated the TGF-β pathway in disease pathogenesis and generation of myofibroblasts in the arterial wall. microRNAs are small non-coding RNAs that modulate gene expression at the post-transcriptional level and can be transported between cells in extracellular vesicles. To understand the role that microRNAs play in modifying gene expression in Kawasaki disease, we studied microRNAs from whole blood during the acute and convalescent stages of the illness.RNA isolated from the matched whole blood of 12 patients with acute and convalescent Kawasaki disease were analyzed by sequencing of small RNA. This analysis revealed six microRNAs (miRs-143, -199b-5p, -618, -223, -145 and -145* (complementary strand)) whose levels were significantly elevated during the acute phase of Kawasaki disease. The result was validated using targeted qRT-PCR using an independent cohort (n = 16). miR-145, which plays a critical role in the differentiation of neutrophils and vascular smooth muscle cells, was expressed at high levels in blood samples from acute Kawasaki disease but not adenovirus-infected control patients (p = 0.005). miR-145 was also detected in small extracellular vesicles isolated from acute Kawasaki disease plasma samples. Pathway analysis of the predicted targets of the 6 differentially expressed microRNAs identified the TGF-β pathway as the top pathway regulated by microRNAs in Kawasaki disease.Sequencing of small RNA species allowed discovery of microRNAs that may participate in Kawasaki disease pathogenesis. miR-145 may participate, along with other differentially expressed microRNAs, in regulating expression of genes in the TGF-β pathway during the acute illness. If the predicted target genes are confirmed, our findings suggest a model of Kawasaki disease pathogenesis whereby miR-145 modulates TGF-β signaling in the arterial wall.
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- 2013
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9. BEAMing and Droplet Digital PCR Analysis of Mutant IDH1 mRNA in Glioma Patient Serum and Cerebrospinal Fluid Extracellular Vesicles
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Walter W Chen, Leonora Balaj, Linda M Liau, Michael L Samuels, Steve K Kotsopoulos, Casey A Maguire, Lori LoGuidice, Horacio Soto, Matthew Garrett, Lin Dan Zhu, Sarada Sivaraman, Clark Chen, Eric T Wong, Bob S Carter, Fred H Hochberg, Xandra O Breakefield, and Johan Skog
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BEAMing PCR ,biomarkers ,cancer ,extracellular vesicles ,droplet digital PCR ,Therapeutics. Pharmacology ,RM1-950 - Abstract
Development of biofluid-based molecular diagnostic tests for cancer is an important step towards tumor characterization and real-time monitoring in a minimally invasive fashion. Extracellular vesicles (EVs) are released from tumor cells into body fluids and can provide a powerful platform for tumor biomarkers because they carry tumor proteins and nucleic acids. Detecting rare point mutations in the background of wild-type sequences in biofluids such as blood and cerebrospinal fluid (CSF) remains a major challenge. Techniques such as BEAMing (beads, emulsion, amplification, magnetics) PCR and droplet digital PCR (ddPCR) are substantially more sensitive than many other assays for mutant sequence detection. Here, we describe a novel approach that combines biofluid EV RNA and BEAMing RT-PCR (EV-BEAMing), as well droplet digital PCR to interrogate mutations from glioma tumors. EVs from CSF of patients with glioma were shown to contain mutant IDH1 transcripts, and we were able to reliably detect and quantify mutant and wild-type IDH1 RNA transcripts in CSF of patients with gliomas. EV-BEAMing and EV-ddPCR represent a valuable new strategy for cancer diagnostics, which can be applied to a variety of biofluids and neoplasms.
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- 2013
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10. On the performance of directional communications in ultra-dense networks.
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Arvind Merwaday, Rath Vannithamby, Mohammad Mamunur Rashid, Yi Zhang 0102, Clark Chen, and Xiaoyun Wu
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- 2017
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11. GESTALT (GammaTile Enhanced Stupp Alternative): Feasibility Study of Resection and GammaTile® Followed by Concomitant External Beam Radiation Therapy (EBRT)/Temozolomide (TMZ) and Adjuvant TMZ in Newly Diagnosed Glioblastoma (GBM) (P13-13.001)
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Erin Dunbar, David McCracken, Adam Nowlan, Kathryn Dusenbery, Claire Ferreira, Stuart Lee, M Sean Peach, Robert Corns, and Clark Chen
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- 2023
12. Supplementary Data 1 from The Meningioma Enhancer Landscape Delineates Novel Subgroups and Drives Druggable Dependencies
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Jeremy N. Rich, David R. Raleigh, Arie Perry, Lukas Chavez, Stephen C. Mack, Michael A. Vogelbaum, Gene H. Barnett, Clark Chen, Qi Xie, Xiuxing Wang, Jair L. Siqueira-Neto, Zhe Zhu, Melike Pekmezci, Ryan C. Gimple, Andrew R. Morton, Bradley H. King, Derrick Lee, Shruti Bhargava, Lisa C. Wallace, Qiulian Wu, Jean A. Bernatchez, Deobrat Dixit, Harish N. Vasudevan, and Briana C. Prager
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Supplementary Data
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- 2023
13. Supplementary Information from The Meningioma Enhancer Landscape Delineates Novel Subgroups and Drives Druggable Dependencies
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Jeremy N. Rich, David R. Raleigh, Arie Perry, Lukas Chavez, Stephen C. Mack, Michael A. Vogelbaum, Gene H. Barnett, Clark Chen, Qi Xie, Xiuxing Wang, Jair L. Siqueira-Neto, Zhe Zhu, Melike Pekmezci, Ryan C. Gimple, Andrew R. Morton, Bradley H. King, Derrick Lee, Shruti Bhargava, Lisa C. Wallace, Qiulian Wu, Jean A. Bernatchez, Deobrat Dixit, Harish N. Vasudevan, and Briana C. Prager
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Supplementary Information
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- 2023
14. Data from The Meningioma Enhancer Landscape Delineates Novel Subgroups and Drives Druggable Dependencies
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Jeremy N. Rich, David R. Raleigh, Arie Perry, Lukas Chavez, Stephen C. Mack, Michael A. Vogelbaum, Gene H. Barnett, Clark Chen, Qi Xie, Xiuxing Wang, Jair L. Siqueira-Neto, Zhe Zhu, Melike Pekmezci, Ryan C. Gimple, Andrew R. Morton, Bradley H. King, Derrick Lee, Shruti Bhargava, Lisa C. Wallace, Qiulian Wu, Jean A. Bernatchez, Deobrat Dixit, Harish N. Vasudevan, and Briana C. Prager
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Meningiomas are the most common primary intracranial tumor with current classification offering limited therapeutic guidance. Here, we interrogated meningioma enhancer landscapes from 33 tumors to stratify patients based upon prognosis and identify novel meningioma-specific dependencies. Enhancers robustly stratified meningiomas into three biologically distinct groups (adipogenesis/cholesterol, mesodermal, and neural crest) distinguished by distinct hormonal lineage transcriptional regulators. Meningioma landscapes clustered with intrinsic brain tumors and hormonally responsive systemic cancers with meningioma subgroups, reflecting progesterone or androgen hormonal signaling. Enhancer classification identified a subset of tumors with poor prognosis, irrespective of histologic grading. Superenhancer signatures predicted drug dependencies with superior in vitro efficacy to treatment based upon the NF2 genomic profile. Inhibition of DUSP1, a novel and druggable meningioma target, impaired tumor growth in vivo. Collectively, epigenetic landscapes empower meningioma classification and identification of novel therapies.Significance:Enhancer landscapes inform prognostic classification of aggressive meningiomas, identifying tumors at high risk of recurrence, and reveal previously unknown therapeutic targets. Druggable dependencies discovered through epigenetic profiling potentially guide treatment of intractable meningiomas.This article is highlighted in the In This Issue feature, p. 1611
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- 2023
15. Supplementary Methods and Table 1 from Mechanistic Rationale to Target PTEN-Deficient Tumor Cells with Inhibitors of the DNA Damage Response Kinase ATM
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Richard D. Kennedy, Kevin M. Prise, D. Paul Harkin, Clark Chen, Karl T. Butterworth, Kienan I. Savage, Katarina Wikstrom, Jie Li, David Gonda, Steven M. Walker, Conor Hanna, and Nuala McCabe
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Supplementary Methods and Table 1. Supplementary Table 1: siRNA target genes
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- 2023
16. Data from Mechanistic Rationale to Target PTEN-Deficient Tumor Cells with Inhibitors of the DNA Damage Response Kinase ATM
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Richard D. Kennedy, Kevin M. Prise, D. Paul Harkin, Clark Chen, Karl T. Butterworth, Kienan I. Savage, Katarina Wikstrom, Jie Li, David Gonda, Steven M. Walker, Conor Hanna, and Nuala McCabe
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Ataxia telangiectasia mutated (ATM) is an important signaling molecule in the DNA damage response (DDR). ATM loss of function can produce a synthetic lethal phenotype in combination with tumor-associated mutations in FA/BRCA pathway components. In this study, we took an siRNA screening strategy to identify other tumor suppressors that, when inhibited, similarly sensitized cells to ATM inhibition. In this manner, we determined that PTEN and ATM were synthetically lethal when jointly inhibited. PTEN-deficient cells exhibited elevated levels of reactive oxygen species, increased endogenous DNA damage, and constitutive ATM activation. ATM inhibition caused catastrophic DNA damage, mitotic cell cycle arrest, and apoptosis specifically in PTEN-deficient cells in comparison with wild-type cells. Antioxidants abrogated the increase in DNA damage and ATM activation in PTEN-deficient cells, suggesting a requirement for oxidative DNA damage in the mechanism of cell death. Lastly, the ATM inhibitor KU-60019 was specifically toxic to PTEN mutant cancer cells in tumor xenografts and reversible by reintroduction of wild-type PTEN. Together, our results offer a mechanistic rationale for clinical evaluation of ATM inhibitors in PTEN-deficient tumors. Cancer Res; 75(11); 2159–65. ©2015 AACR.
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- 2023
17. Supplementary Figures 1-4 from Mechanistic Rationale to Target PTEN-Deficient Tumor Cells with Inhibitors of the DNA Damage Response Kinase ATM
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Richard D. Kennedy, Kevin M. Prise, D. Paul Harkin, Clark Chen, Karl T. Butterworth, Kienan I. Savage, Katarina Wikstrom, Jie Li, David Gonda, Steven M. Walker, Conor Hanna, and Nuala McCabe
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Supplementary Figures 1-4. Figure 1: ATM is a potential drug target for PTEN-deficient cells Figure 2: The synthetic lethality with PTEN loss and ATM inhibition is independent of AKT function Figure 3: The synthetic lethality with PTEN loss and ATM inhibition is independent of RAD51 function Supplementary Figure 4: In vivo efficacy of ATM inhibition with PTEN loss
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- 2023
18. Strong‐Proton‐Adsorption Co‐Based Electrocatalysts Achieve Active and Stable Neutral Seawater Splitting
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Ning Wang, Pengfei Ou, Sung‐Fu Hung, Jianan Erick Huang, Adnan Ozden, Jehad Abed, Ivan Grigioni, Clark Chen, Rui Kai Miao, Yu Yan, Jinqiang Zhang, Ziyun Wang, Roham Dorakhan, Ahmed Badreldin, Ahmed Abdel‐Wahab, David Sinton, Yongchang Liu, Hongyan Liang, and Edward H. Sargent
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Mechanics of Materials ,Mechanical Engineering ,General Materials Science - Published
- 2023
19. SWAN: End-to-end orchestration for cloud network and WAN.
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Haiyang Qian, Xin Huang 0008, and Clark Chen
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- 2013
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20. Multi-user MIMO and adaptive frequency reuse for next-generation mobile broadband networks.
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Clark Chen, Yang-Seok Choi, Nageen Himayat, Minnie Ho, Vladimir Kravtsov, Guangjie Li, Qinghua Li, Yuval Lomnitz, Hongmei Sun, Hua Yang, Shilpa Talwar, Hujun Yin, Hongming Zheng, and Shanshan Zheng
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- 2009
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21. BIOM-43. THE GENOMIC, TRANSCRIPTOMIC, AND EPIGENOMIC LANDSCAPE OF ISOCITRATE DEHYDROGENASE WILD TYPE GLIOBLASTOMA ACROSS THE AGE CONTINUUM
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Margaret Johnson, April Bell, Yajas Shah, Kayla Viets-Layng, Elizabeth Mauer, Joanne Xiu, Olivier Elemento, Michael Glantz, Phillip Walker, Clark Chen, Erin Dunbar, Ekokobe Fonkem, Santosh Kesari, Andrew Brenner, Herbert Newton, Justin Low, Ashley Sumrall, Wolfgang Korn, David Ashley, and Derek Wainwright
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Cancer Research ,Oncology ,Neurology (clinical) - Abstract
BACKGROUND Older age is a poor prognostic factor for glioblastoma (GBM) patients. We tested whether the intrinsic molecular landscape of the tumor may contribute to this poor prognosis. METHODS In accordance with the 2021 WHO classification scheme, we included only isocitrate dehydrogenase (IDH) wild type GBM. Based on published literature, we defined older as age > 65. RNA expression, gene amplification, tumor mutational burden (TMB) and mutational profiles were analyzed in three unique datasets: Tempus (n = 1,410), Caris (n = 1,432), and TCGA (n = 557). Comparison were made between < 65 and ³ 65 year olds using Pearson’s Chi-squared tests, Fisher’s exact tests, or Wilcoxon rank-sum where appropriate. RESULTS From our evaluable gene sets, TERT promoter mutations were more prevalent in patients ³ 65 years old (Caris 82.64 vs 77.27%, p = 0.016; Tempus 58.0 vs 49.0%, p = 0.002). There were no significant differences in PDCD1, CD274, CD3E, TNFRSF18, CD40, CD8A, TNFRSF4, CTLA4, HAVCR2, TNFSF9, CD274, or CDKN2A; PDL-1 (by IHC); dMMR/MSI-H, TMB; CDK6 amplification, EGFR amplification, EGFR, EGFRvIII, EGFR fusions, MET fusions, PTEN, TP53, or NF-1. MGMT promoter methylation (Caris data) was more common in the older group (49.73 v 34.14%, p < 0.001). TGCA data demonstrated that gene expression, TMB, and methylation did not change significantly with age. Additionally, PCOLCE2 and SLC10A4 were differentially methylated, and missense mutations, of any type, were more common in the older group (p=0.006). CONCLUSION Despite worse survival outcomes for older patients with IDHwt GBM as compared to younger counterparts, the molecular landscape is similar at the genomic, transcriptomic and epigenomic levels. The key exception is TERT promoter mutations that are more common in older GBM patients. Poorer survival is therefore not likely to be attributable solely to intratumoral factors.
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- 2022
22. SURG-23. EFFICACY OF LASER INTERSTITIAL THERMAL THERAPY (LITT) FOR NEWLY DIAGNOSED AND RECURRENT IDH WILD-TYPE GLIOBLASTOMA
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John de Groot, Albert Kim, Sujit Prabhu, Ganesh Rao, Adrian Laxton, Peter Fecci, Barbara O'Brien, Andrew Sloan, Veronica Chiang, Stephen Tatter, Alireza Mohammadi, Dimitris Placantonakis, Roy Strowd, Clark Chen, Constantinos Hadjipanayis, Mustafa Khasraw, David Sun, David Piccioni, Kaylyn Sinicrope, Jian Campian, Sylvia Kurz, Brian Williams, Kris Smith, Zulma Tovar-Spinoza, and Eric Leuthardt
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Cancer Research ,Oncology ,Neurology (clinical) - Abstract
Treatment options for glioblastoma remain limited, particularly for those who are not eligible for traditional resection, whether due to lesion location or inability to tolerate open craniotomy. Maximal-safe resection followed by radiation with concurrent and adjuvant temozolomide offers the best outcomes for patients. Unfortunately, not all tumors are amenable to conventional surgical resection at the time of diagnosis with only about 1/3 of patients able to receive a gross-total resection and 15-25% of patients receiving biopsy only, thus reducing their projected overall survival to 9 months. Laser interstitial thermal therapy (LITT) is a minimally invasive, cytoreductive tool, that has demonstrated safety as a surgical approach to treat primary brain tumors. METHODS Data from LAANTERN prospective multicenter registry (NCT02392078) was analyzed to determine clinical outcomes for patients with new and recurrent IDH wild-type glioblastoma (N=89). Demographics, intraprocedural data, adverse events, KPS, health-economics, and survival data were prospectively collected then analyzed separately for newly diagnosed GBM (N=29) and recurrent GBM (N=60). RESULTS Median overall-survival was 9.73 months (95% CI: 5.16, 15.91) for newly diagnosed patients and median post-procedure survival was 8.97 (6.94, 12.36) months for recurrent patients. Median overall-survival for newly diagnosed patients receiving post-LITT chemoradiotherapy was 16.14 months (6.11, not reached). The median length of hospital stay was 50 hours and 80% of patients were discharged to home. CONCLUSIONS LITT offers an effective cytoreductive approach for patients with newly diagnosed and recurrent IDH wild-type glioblastoma. Importantly, its use in newly diagnosed patients who receive post-LITT chemoradiotherapy leads to a median OS similar to that of patients treated with conventional surgical resection. LITT remains an important alternative for patients with inoperable tumors or those not amenable to resection. Enrollment in LAANTERN is ongoing and these cohorts will be revisited as data continues to mature. Benefits beyond cytoreduction are also being actively explored.
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- 2022
23. EPID-15. SURGICAL RESECTION OF BENIGN MENINGIOMAS IN THE ELDERLY POPULATION: IMPLICATIONS FROM A PROPENSITY-SCORE MATCHED ANALYSIS
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Jun Ma, Ping Zhu, and Clark Chen
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Cancer Research ,Oncology ,Neurology (clinical) - Abstract
Object We characterized the patterns of clinical practice in benign meningioma resection and survival outcome as a function of patient age using the Surveillance, Epidemiology and End Results (SEER) and the SEER-Medicare database. METHODS The likelihood for recommendation to proceed with resection and survival in adult, benign meningioma patients were characterized using logistic regression. Survival analysis was performed using a propensity-score matching (PSM)-method (covariates balanced in PSM: socio-demographics, facility features, and comorbidities) through a multivariable logistic regression and accelerated failure time (AFT) models. RESULTS The likelihoods of recommendation for surgery were 0.59 (95%CI = 0.53-0.66, P < 0.001) and 0.17 (95%CI = 0.15-0.21, P < 0.001) for meningioma patients age 60-79 and ≥ 80, relative to patients age 40-59. Expectedly, the hazard of death increased with advancing aging strata in patients who underwent meningioma resection. To account for mortality risk associated with normal aging, a PSM analysis was performed to calculate the hazard of death for surgically resected meningioma patients relative to an age- and PSM-matched cancer-free patient cohort. This odds ratio (OR) was 3.84 (95%CI: 3.15-4.67, P < 0.001) for patients age 60-79 and 3.41 (95%CI: 2.56-4.56, P < 0.001) for patients age ≥ 80. These two ORs were not statistically different (ROR: 0.89, 95%CI: 0.63-1.62, P = 0.512), suggesting that the likelihood of death after benign meningioma resection was not significantly elevated in patients age ≥ 80 after accounting for expected age-related mortality. CONCLUSION Our study suggests that surgeons exert caution in selecting elderly with meningioma for resection. After accounting for mortality risk associated with normal aging and patient selection by the surgeon, the likelihood of death for patients age ≥ 80 who underwent meningioma resection was comparable to that observed for patients age 60-79.
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- 2022
24. EPID-24. TIMING OF STANDARD-OF-CARE CHEMO-RADIATION THERAPY FOLLOWING SURGICAL RESECTION OR STEREOTACTIC BIOPSY
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Ping Zhu and Clark Chen
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Cancer Research ,Oncology ,Neurology (clinical) - Abstract
OBJECT The literature examining the optimal timing for initiating post-surgical therapy after glioblastoma surgery is brimming with inconsistencies, with reports of both deleterious effects and benefits in the delay of post-surgical therapy at various time intervals. Moreover, there is currently limited data pertinent to the post-Stupp regimen era. Here, we use the National Cancer Database (NCDB) to explore this matter, with a focus on patients who underwent the standard-of-care (SOC) Stupp regimen. METHODS The study cohort included newly glioblastoma patients from the NCDB, with exclusion of patients age < 40 [as proxy for isocitrate dehydrogenase (IDH) mutated astrocytoma] and stratified for Methyl-guanine-methyl transferase (MGMT) promotor methylation. Timing of initiating SOC was grouped by 0-2, 2-4, 4-6, 6-8, and > 8 weeks from surgery. Biopsy and craniotomy patients were analyzed separately. The Kaplan-Meier method and Cox proportional hazards regression were applied for survival analysis. RESULTS We identified 6511 glioblastoma patients who underwent SOC therapy with available MGMT methylation status. SOC was initiated in 228 (3.5%), 2478 (38.1%), 2954 (45.4%), 646 (9.9%), and 205 (3.2%) patients at 0-2, 2-4, 4-6, 6-8, and >8 weeks after surgery. For craniotomy patients, initiation of SOC at 0-2 weeks was associated with an increased risk of death relative to SOC initiation at 4-6 weeks (HR: 1.19, p = 0.036). These results remain robust after controlling for the extent of resection, tumor size, and tumor location (HR: 1.19, p = 0.044). Such association was not observed in patients who underwent stereotactic biopsy (HR: 1.27, p = 0.148). Patients who received SOC at 6-8 weeks post-craniotomy (HR: 0.96, p = 0.420) or biopsy (HR: 0.93, p = 0.628) did not appear to worsen survival outcomes. CONCLUSION Optimal timing for initiation of SOC differ for craniotomy and needle biopsy patients. Initiating SOC within 2 weeks after craniotomy could lead to worse survival outcomes for GBM patients.
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- 2022
25. Efficacy of laser interstitial thermal therapy (LITT) for newly diagnosed and recurrent
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John F, de Groot, Albert H, Kim, Sujit, Prabhu, Ganesh, Rao, Adrian W, Laxton, Peter E, Fecci, Barbara J, O'Brien, Andrew, Sloan, Veronica, Chiang, Stephen B, Tatter, Alireza M, Mohammadi, Dimitris G, Placantonakis, Roy E, Strowd, Clark, Chen, Constantinos, Hadjipanayis, Mustafa, Khasraw, David, Sun, David, Piccioni, Kaylyn D, Sinicrope, Jian L, Campian, Sylvia C, Kurz, Brian, Williams, Kris, Smith, Zulma, Tovar-Spinoza, and Eric C, Leuthardt
- Abstract
Treatment options for unresectable new and recurrent glioblastoma remain limited. Laser ablation has demonstrated safety as a surgical approach to treating primary brain tumors. The LAANTERN prospective multicenter registry (NCT02392078) data were analyzed to determine clinical outcomes for patients with new and recurrentDemographics, intraprocedural data, adverse events, KPS, health economics, and survival data were prospectively collected and then analyzed onA total of 29 new and 60 recurrentLaser ablation is a viable option for patients with new and recurrent glioblastoma. Median OS for
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- 2022
26. New Research Directions in DNA Repair
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Clark Chen
- Published
- 2013
27. EXTH-64. IPSC-DERIVED NK CELLS EXHIBIT POTENT IN VITRO AND IN VIVO TUMORCIDAL ACTIVITY AGAINST PATIENT-DERIVED GLIOBLASTOMA STEM CELLS (GSCS)
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Jianfang Ning, Zachary Davis, Frank Cichocki, Hongbo Wang, Katie Tuininga, Ryan Bjordahl, Tom Lee, Jeffrey Miller, and Clark Chen
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Cancer Research ,Oncology ,Neurology (clinical) - Abstract
INTRODUCTION Natural Killer (NK) cells play pivotal roles in cancer immune surveillance and harbor potent anti-tumor activities. We have engineered an induced pluripotent stem cells (iPSCs) derived, NK cell (termed FT538) that express 1) a high-affinity non-cleavable CD16 Fc receptor to facilitate antibody engagement, 2) a membrane-bound IL-15/IL-15 receptor fusion to enhance NK activity and persistence and 3) a knock-out of CD38 to enhance NK metabolic fitness. FT538 is produced in a GMP-compliant manner as an off-the-shelf immunotherapy. Clinical experiences with FT538 have shown evidence of durable anti-tumor immunity after single administration in select lymphoma patients. METHODS We performed pre-clinical studies to characterize the tumoricidal activity of FT573 against glioblastomas. RESULTS Without specific antibody to engage CD16, FT538 exhibited potent in vitro activity against ~80% of a panel of isocitrate dehydrogenase wild-type patient-derived xenograft (PDX) glioblastoma lines, including MGG8. When directly injected into the murine brain, 50% of the FT538 persisted for > 2 weeks without addition of exogenous cytokine. Moreover, the mice exhibited no evidence of neurologic compromise, and brains harvested after injection show no signs of FT538 activation. In vivo intratumoral injection of FT538 into an orthotopically established MGG8 glioblastoma caused a ~20 fold increase in granzyme B release by FT538, with a comparable increase of cleaved-caspase 3 in the tumor. In independent experiments, > 90% of mice orthotopically implanted MGG8 survived beyond 100 days after intra-tumoral FT538 while all mice treated with mock injection died by 60 days. For glioblastoma PDX refractory to FT538, such as MGG4, tumoricidal activity of FT583 can be induced in vitro and in vivo by the addition of a tri-specific engager targeting B7H3, a surface protein highly expressed in glioblastomas. CONCLUSION Our results demonstrate great promise of FT538 as a glioblastoma therapy, with plans for translation into a first-in-human clinical trial.
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- 2022
28. DDDR-16. GBP3-STING INTERACTION IN GLIOBLASTOMA COORDINATES AUTOPHAGY, ANTI-OXIDATIVE, AND DNA REPAIR PROGRAMS IN RESPONSE TO TEMOZOLOMIDE
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Ming Li and Clark Chen
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Cancer Research ,Oncology ,Neurology (clinical) - Abstract
INTRODUCTION Guanylate-binding proteins (GBPs) are a group of dynamin-related large (~65 kDa) GTPases expressed in response to interferon and mediate intracellular immunity. In contrast to the Ras- or Rho family of small GTPases (~20 kDa) or the trimeric GTPases, little is known about the function of GBPs beyond their role in innate cellular immunity. METHODS Informatic analysis of clinically annotated glioblastoma datasets, laboratory studies of protein-protein interaction, functional characterization after depletion or exogenous expression RESULTS Of the seven known members of human GBPs, only GBP3 showed significant up-regulation in response to temozolomide, the standard-of-care DNA-alkylating chemotherapy for glioblastoma. Importantly, high levels of glioblastoma GBP3 expression was associated with worsened survival after temozolomide treatment. Consistent with this observation, exogenous expression of GBP3 induced temozolomide resistance in independent patient-derived glioblastoma neurosphere lines, while GBP3 silencing conferred temozolomide sensitivity, both in vitro and in vivo. This sensitivity was associated with the accumulation of cytoplasmic DNA fragments, suggesting the involvement of STING. Supporting this hypothesis, the N-terminal of GBP3 physically interacted with STING to prevent proteasome-mediated degradation of STING. Since cytoplasmic DNA bound STING activates key transcriptional programs, we profiled transcription programs requiring both GBP3 and STING expression and identified an autophagy program mediated by p62 (autophagy), a defense program against oxidative insults mediated by nuclear factor erythroid 2 like 2 (NFE2L2, NRF2), and a DNA repair program mediated by O6-methylguanine-DNA-methyltransferase (MGMT). These programs were previously shown to play central roles in cellular resistance to DNA alkylating agents. CONCLUSION In addition to its central role in innate immunity, GBP3 mediates cellular response to DNA damage through coordination of autophagy, anti-oxidative, and DNA repair programs.
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- 2022
29. RBIO-03. A MULTI-INSTITUTIONAL EXPERIENCE OF GAMMATILE BRACHYTHERAPY AS TREATMENT FOR RECURRENT GLIOBLASTOMAS
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Clark Chen, Clara Ferreira, Kathryn Dusenbery, Kimberly Hoang, Stuart Lee, and Kris Smith
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Cancer Research ,Oncology ,Neurology (clinical) - Abstract
BACKGROUND Recurrent glioblastoma remains a disease without established standard of care. Here, we report the safety profile and survival outcome of recurrent glioblastoma patients treated with maximal safe resection followed by intraoperative placement of GammaTile (GT), a collagen tile-embedded Cs-131 brachytherapy platform. METHODS The study included isocitrate Dehydrogenase (IDH) wild-type glioblastoma patients who suffered tissue confirmed recurrence after concurrent temozolomide-radiation therapy. The series included consecutively patients treated at the University of Minnesota, Barrow Neurological Institute, Vidant Health, and Emory University Hospital. Survival results were stratified by methyl-guanine methyl transferase (MGMT) promoter methylation status RESULTS In total 48 patients were treated between 2019 and 2022 in this multi-institutional experience. The median days of hospitalization following the procedure was two (range: 1-15), with 72.5% of the GT implanted patients discharged home before postoperative day three. In terms of post-operative course, two patients suffered new-onset seizure post-surgery (4.0%). There was one (2%) 30-day mortality from intracranial hemorrhage secondary to heparinization for an ischemic limb. There were 13% readmission within 30 days, including hydrocephalus (n=2), urinary tract infection (n=1), deep venous thrombosis (n=1), failure to thrive (n=1), and infected wound (n=1). Of note, the patient with the infected wound had suffered a previous wound infection prior to the GT implantation and the pathogenic organism for both infections were the same (S. aureus). With a median follow-up of 250 days, twelve-month local control was 82%. Median overall survival (OS) from the time of diagnosis was 19 and 33 months for the MGMT unmethylated and methylated tumors, respectively. Select patients (n = 6) treated with adjuvant ketogenic diet in addition to GT and subsequent chemotherapy exhibited survival beyond expectation (> 14 mo, median survival not reached). CONCLUSION This multi-institutional experience supports further investigation of GT brachytherapy as a treatment for recurrent glioblastomas.
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- 2022
30. DDDR-24. INTEGRATED ANALYSIS OF SINGLE CELL CHROMATIN ACCESSIBILITY AND RNA EXPRESSION IDENTIFIED COMMON VULNERABILITY DESPITE GLIOBLASTOMA HETEROGENEITY
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Ramya Raviram, Anugraha Raman, Sebastian Preissl, Shaoping Wu, Tomoyuki Koga, Chenxu Zhu, Jens Luebeck, Kinsey Van Deynze, Jee Yun Han, Xioameng Hou, Zhen Ye, Anna Mischel, Yang Eric Li, Rongxin Fang, Tomas Baback, Joshua Mugford, Claudia Han, Christopher Glass, Cathy Barr, Paul Mischel, Vineet Bafna, Laura Escoubet, Bing Ren, and Clark Chen
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Cancer Research ,Oncology ,Neurology (clinical) - Abstract
INTRODUCTION In 2021, the World Health Organization (WHO) reclassified glioblastoma, the most common form of adult brain cancer, into isocitrate dehydrogenase (IDH) wild-type glioblastomas and grade IV IDH mutant (G4 IDHm) astrocytomas. For both tumor types, intra-tumoral heterogeneity is a key contributor to therapeutic failure. METHODS we applied integrated genome-wide chromatin accessibility (snATACseq) and transcription (snRNAseq) profiles to clinical specimens derived IDHwt glioblastomas and G4 IDHm) astrocytomas, with goal of therapeutic target discovery. RESULTS The integrated analysis achieved resolution of intra-tumoral heterogeneity not previously possible, providing a molecular landscape of extensive regional and cellular variability. snATACseq delineated focal amplification down to an ~40 KB resolution. The snRNA analysis elucidated distinct cell types and cell states (neural progenitor/oligodendrocyte cell-like or astrocyte/mesenchymal cell-like) that were superimposable onto the snATACseq landscape. Paired-seq (parallel snATACseq and snRNAseq using the same clinical sample) provided high resolution delineation of extrachromosomal circular DNA (ecDNA), harboring oncogenes including CCND1 and EGFR. Importantly, the copy number of ecDNA genes correlated closely with the level of RNA expression. Integrated analysis across all specimens profiled suggests that IDHm grade 4 astrocytoma and IDHwt glioblastoma cells shared a common chromatin structure defined by open regions enriched for Nuclear Factor 1 transcription factors (NFIA and NFIB). Silencing of NF1A or NF1B suppressed in vitro and in vivo growth of patient-derived IDHwt glioblastomas and G4 IDHm astrocytoma models that mimic distinct glioblastoma cell states. CONCLUSION Our findings suggest despite distinct genotypes and cell states, glablastoma/G4 astrocytoma cells share dependency on core transcriptional programs, yielding an attractive platform for addressing therapeutic challenges associated with intra-tumoral heterogeneity.
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- 2022
31. EPID-21. INCORPORATING RECEIPT OF STANDARD-OF-CARE AS A KEY VARIABLE IN POPULATION-BASED STUDY OF GLIOBLASTOMA SURVIVAL
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Ping Zhu and Clark Chen
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Cancer Research ,Oncology ,Neurology (clinical) - Abstract
Object Populational database research with real-world settings offers epidemiologic insight at scales that cannot be easily recapitulated, especially for rare cancers such as glioblastoma. However, most survival studies were conducted without consideration for whether the patients received the standard of care (SOC). METHODS Survival analysis was performed using the National Cancer Database (NCDB) and stratified for Methyl-guanine-methyl transferase (MGMT) promotor methylation. Glioblastoma patients age < 40 were excluded to minimize the prognostic impact of isocitrate dehydrogenase (IDH) mutations. SOC was defined as the receipt of chemotherapy and radiation within 2-6 weeks of surgical biopsy or resection. Sensitivity analyses were performed allowing chemotherapy and radiation start date to differ by 0, 3, 5, and 10 days. RESULTS Within the NCDB (N = 11231), 54.7% of newly diagnosed glioblastoma patients did not receive SOC. The median survival time (MST) estimates were significantly shorter for all glioblastoma patients (10.9, IQR: 4.3-21.5, months) relative to SOC treated patients (15.3, IQR: 8.6-26.2, months; p < 0.001). The MST estimates remain stable in sensitivity analysis allowing for 0, 3, 5, and 10-day discrepancy between chemotherapy and radiation start date. These results were recapitulated using the SEER-Medicare database. The MST estimates for MGMT methylated and unmethylated glioblastoma patients after SOC in the NCDB were 21.0 and 14.5-mo, respectively. The overall and MGMT-specific survival estimates mirror those reported by the SOC arms of five recent randomized controlled studies. Analysis of all glioblastoma patients indicates survival benefit of immunotherapy (HR: 0.90, p = 0.020) while such benefit was absent in SOC treated patients (HR: 0.97, p = 0.644) - with the latter observation more reflective with trial results and clinical experiences. CONCLUSION Survival analysis in the populational database study can be misleading without information on the receipt of SOC.
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- 2022
32. SYST-14 CLINICAL EFFICACY OF ONC201 IN RECURRENT H3 K27M-MUTANT DIFFUSE MIDLINE GLIOMA (DMG) PATIENTS
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Isabel Arrillaga-Romany, Sylvia Kurz, Rohinton Tarapore, Guangrong Lu, Ashley Sumrall, Nicholas Butowski, Rebecca Harrison, John DeGroot, Andrew Chi, Nicole Shonka, Yoshie Umemura, Yazmin Odia, Minesh Mehta, Phioanh Nghiemphu, Timothy Cloughesy, Lynne Taylor, Jerome Graber, Lindsay Kilburn, Karan Dixit, Clark Chen, Sharon Gardner, Dolly Aguilera, Tobey MacDonald, Andrew Cluster, Kathan Mehta, Albert Kheradpour, Allen Melemed, Joshua E Allen, Tracey Batchelor, Andrew Lassman, and Patrick Wen
- Subjects
General Medicine - Abstract
BACKGROUND H3 K27M-mutant DMG predominantly affects children and young adults; no effective therapy is known. ONC201 is a first-in-class, anti-cancer DRD2 antagonist and ClpP agonist. METHODS Fifty pediatric and adult patients with recurrent H3 K27M DMG who received oral ONC201 monotherapy in clinical trials and expanded access were selected for a planned efficacy analysis. Eligibility criteria included measurable contrast-enhancing disease by RANO-HGG criteria (excluding pontine and spinal cord tumors), KPS/LPS≥60, ≥90 days from prior radiation, and adequate washout from prior anti-cancer therapy. The primary endpoint was overall response rate (ORR) by RANO-HGG criteria. Secondary endpoints included duration of response, time to response, progression-free survival (PFS), overall survival (OS), corticosteroid response rate, performance status response rate, and ORR by RANO-LGG criteria. Radiographic endpoints were assessed by dual-reader blinded independent central review. Data cutoff was May 31, 2021. RESULTS ORR was 20.0% (95%CI, 10.0–33.7) by RANO-HGG criteria. Median duration of response was 11.2 months (95%CI, 3.8–not reached) and median time to response was 8.3 months (range, 1.9–15.9). PFS at 6 months was 35.1% (95%CI, 21.2–49.3). The ORR was 26.0% (95%CI, 14.6–40.3) by RANO-LGG criteria. Fifteen patients (30.0%; 95%CI, 17.9–44.6) achieved an objective response by RANO-HGG and/or RANO-LGG criteria. Of 15 patients receiving ≥4 mg daily dexamethasone at baseline, 7 (46.7%; 95%CI, 21.3–73.4) achieved ≥50% confirmed reduction in dose. Of 34 patients with baseline KPS/LPS CONCLUSIONS ONC201 monotherapy exhibits durable and clinically meaningful efficacy in recurrent H3 K27M-mutant DMG.
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- 2022
33. Early versus delayed postoperative radiotherapy for treatment of low-grade gliomas
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Sanjay Dhawan, Chirag G Patil, Clark Chen, and Andrew S Venteicher
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medicine.medical_specialty ,Time Factors ,Biopsy ,medicine.medical_treatment ,Postoperative radiotherapy ,Radiosurgery ,Disease-Free Survival ,Article ,Seizures ,Glioma ,Humans ,Medicine ,Pharmacology (medical) ,Progression-free survival ,Watchful Waiting ,Randomized Controlled Trials as Topic ,Postoperative Care ,Radiotherapy ,medicine.diagnostic_test ,Brain Neoplasms ,business.industry ,medicine.disease ,Progression-Free Survival ,Surgery ,Radiation therapy ,Regimen ,Disease Progression ,business ,Watchful waiting - Abstract
BACKGROUND: This is an update of the review originally published in 2011 and first updated in 2015. In most people with low‐grade gliomas (LGG), the primary treatment regimen remains a combination of surgery followed by postoperative radiotherapy. However, the optimal timing of radiotherapy is controversial. It is unclear whether to use radiotherapy in the early postoperative period, or whether radiotherapy should be delayed until tumour progression occurs. OBJECTIVES: To assess the effects of early postoperative radiotherapy versus radiotherapy delayed until tumour progression for low‐grade intracranial gliomas in people who had initial biopsy or surgical resection. SEARCH METHODS: Original searches were run up to September 2014. An updated literature search from September 2014 through November 2019 was performed on the following electronic databases: the Cochrane Central Register of Controlled Trials (CENTRAL; 2019, Issue 11), MEDLINE via Ovid (September 2014 to November week 2 2019), and Embase via Ovid (September 2014 to 2019 week 46) to identify trials for inclusion in this Cochrane review update. SELECTION CRITERIA: We included randomised controlled trials (RCTs) that compared early versus delayed radiotherapy following biopsy or surgical resection for the treatment of people with newly diagnosed intracranial LGG (astrocytoma, oligodendroglioma, mixed oligoastrocytoma, astroblastoma, xanthoastrocytoma, or ganglioglioma). Radiotherapy may include conformal external beam radiotherapy (EBRT) with linear accelerator or cobalt‐60 sources, intensity‐modulated radiotherapy (IMRT), or stereotactic radiosurgery (SRS). DATA COLLECTION AND ANALYSIS: Three review authors independently assessed the trials for inclusion and risk of bias, and extracted study data. We resolved any differences between review authors by discussion. Adverse effects were also extracted from the study report. We performed meta‐analyses using a random‐effects model with inverse variance weighting. MAIN RESULTS: We included one large, multi‐institutional, prospective RCT, involving 311 participants; the risk of bias in this study was unclear. This study found that early postoperative radiotherapy was associated with an increase in time to progression compared to observation (and delayed radiotherapy upon disease progression) for people with LGG but did not significantly improve overall survival (OS). The median progression‐free survival (PFS) was 5.3 years in the early radiotherapy group and 3.4 years in the delayed radiotherapy group (hazard ratio (HR) 0.59, 95% confidence interval (CI) 0.45 to 0.77; P < 0.0001; 311 participants; 1 trial; low‐quality evidence). The median OS in the early radiotherapy group was 7.4 years, while the delayed radiotherapy group experienced a median overall survival of 7.2 years (HR 0.97, 95% CI 0.71 to 1.33; P = 0.872; 311 participants; 1 trial; low‐quality evidence). The total dose of radiotherapy given was 54 Gy; five fractions of 1.8 Gy per week were given for six weeks. Adverse effects following radiotherapy consisted of skin reactions, otitis media, mild headache, nausea, and vomiting. Rescue therapy was provided to 65% of the participants randomised to delayed radiotherapy. People in both cohorts who were free from tumour progression showed no differences in cognitive deficit, focal deficit, performance status, and headache after one year. However, participants randomised to the early radiotherapy group experienced significantly fewer seizures than participants in the delayed postoperative radiotherapy group at one year (25% versus 41%, P = 0.0329, respectively). AUTHORS' CONCLUSIONS: Given the high risk of bias in the included study, the results of this analysis must be interpreted with caution. Early radiation therapy was associated with the following adverse effects: skin reactions, otitis media, mild headache, nausea, and vomiting. People with LGG who underwent early radiotherapy showed an increase in time to progression compared with people who were observed and had radiotherapy at the time of progression. There was no significant difference in overall survival between people who had early versus delayed radiotherapy; however, this finding may be due to the effectiveness of rescue therapy with radiation in the control arm. People who underwent early radiation had better seizure control at one year than people who underwent delayed radiation. There were no cases of radiation‐induced malignant transformation of LGG. However, it remained unclear whether there were differences in memory, executive function, cognitive function, or quality of life between the two groups since these measures were not evaluated.
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- 2020
34. SURG-02. Stereotactic Laser Ablation (SLA) followed by consolidation stereotactic radiosurgery (SRS) as a treatment strategy for brain metastasis that recurred locally after initial radiosurgery (BMRS): a collaborative institutional experience
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Isabela Pena-Pino, Jun Ma, Yusuki Hori, Elena Fomchenko, Kathryn Dusenbery, Margaret Reynolds, Christopher Wilke, Jianling Yuan, Gene Barnett, Veronica Chiang, Alireza Mohammadi, and Clark Chen
- Subjects
fungi ,AcademicSubjects/MED00300 ,Surgery ,AcademicSubjects/MED00310 ,Supplement Abstracts - Abstract
Introduction In independent clinical trials, ~30% of brain metastases recur locally after radiosurgery (BMRS). For these lesions, treatment with stereotactic laser ablation (SLA, also known as laser interstitial thermal therapy (LITT)) alone achieves a 12-month local control (LC12) of 54–85% while repeat SRS achieved LC12 of 54–79%. Here, we report favorable outcomes for BMRS treated with SLA followed by consolidation radiosurgery (SLA/cSRS). Methods Clinical outcome of 18 patients with 19 histologically confirmed BMRS treated with SLA followed by consolidation SRS and >3 months follow-up were collected retrospectively across three institutions. Local control was defined as stability or decrease in contrast-enhancing (CE) and FLAIR volume. Results SLA achieved ablation of 73–100% of the BMRS CE volumes. Consolidation hypo-fractionated radiosurgery (5 Gy x 5 or 6 Gy x 5) was carried out 16–40 days post-SLA (median of 26 days). With a median follow-up of 185 days (range: 93–1367 days) and median overall survival (OS) of 185 days (range: 99–1367 days), 100% LC12 was achieved. 13/18 (72%) patients that required steroid therapy prior to SLA/cSRS were successfully weaned off steroid by three months post-SLA/cSRS. Post-SLA, KPS declined for 3/19 (16%) patients and improved for 1/19 (5%) patients. No KPS changes occurred subsequent to consolidation SRS. There were no 30-day mortalities or wound complications. Two patients required re-admission within 30 days of SRS (severe headache that resolved with steroid therapy (n=1) and new-onset seizure (n=1)). Except for two patients who suffered histologically confirmed, local failure at 649 and 899 days, all other patients are either alive (n=5) or died from systemic disease progression (n=11). None of the treated patients developed symptomatic radiation necrosis. Conclusions This collaborative institutional experience support efficacy and safety of SLA followed by consolidation SRS as a treatment for BMRS. The treatment strategy warrants further investigations.
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- 2021
35. TRLS-05. A multicenter observational study of Cs-131 seeds embedded in a collagen carrier tile for newly diagnosed and recurrent operable intracranial neoplasms –Trial in progress
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Erin Dunbar, D Jay McCracken, Adam Nowlan, Clark Chen, Kathryn Dusenbery, Clara Ferreira, Rupesh Kotecha, Michael McDermott, Sivakumar Jaikumar, Colette Shen, David Monyak, John Trusheim, John Wanebo, Samuel Day, Stuart Lee, Zabi Wardak, Toral Patel, Mehee Choi, Lisa Misell, and David Brachman
- Abstract
Background For patients with operable intracranial neoplasms, there are opportunities to augment local control beyond traditional methods, such as external beam radiation therapy (EBRT),. Brachytherapy, the implantation of radioactive sources into the resection cavity, can be useful in this setting by providing immediate initiation of radiation and limiting the exposure of surrounding normal tissue to radiation. Traditional intracranial brachytherapy methods have been limited by uneven dose distributions, complicated workflows, extended procedural times, the cost of dedicated equipment, and frequent adverse events. To address these issues, a permanently implanted device with Cs-131 radiation seeds embedded in a bioresorbable collagen carrier tile (GammaTile, GT Medical Technologies, Tempe, AZ USA) was developed. Described as surgically targeted radiation therapy (STaRT), it is FDA-cleared for use in newly-diagnosed malignant intracranial neoplasms and recurrent intracranial tumors, including brain metastases, and has demonstrated excellent safety and local control in early commercial use. The primary objectives of this multicenter, prospective, observational (phase IV) registry study [NCT04427384] are to evaluate “real-world” clinical outcomes and patient-reported outcomes that measure the safety and efficacy of STaRT using the device. Methods Subjects (N=600) at up to 50 enrolling sites undergoing resection of brain tumors of any pathology with intra-operative GammaTile placement are eligible for enrollment. We project 40% of enrollees to have brain metastasis. Tumor pathology, overall survival, radiation- and surgery-related adverse events, quality of life, serial MRIs, and timing of surgical bed recurrence and/or distant recurrence will be collected. The powered primary endpoint for recurrent brain metastases, surgical bed-progression free survival, will compare STaRT to standard-of-care benchmarks. This study will be the first observational study of resection plus GammaTile. Results will be used to benchmark clinical outcomes in the real-world setting, allow for comparisons to existing treatments, and facilitate the design of future clinical trials.
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- 2021
36. Harnessing antiviral memory T cells for tumor immunotherapy
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Pamela Rosato, Sathi P Wijeyesinghe, Jianfang Ning, Noah Veis Gavil, Shaoping Wu, Clark Chen, Vaiva Vezys, and David Masopust
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Immunology ,Immunology and Allergy - Abstract
Overcoming the immunosuppressive tumor microenvironment remains a major impediment to successful cancer immunotherapy. Virus-specific memory T cells are positioned throughout the entire body to sense reinfection or recrudescence. Mouse models have demonstrated upon reencountering cognate antigen, these tissue resident memory T cells (TRM) induce a local immunostimulatory environment that activates and recruits innate and adaptive arms of the immune system, and we extend these functions to include recruitment of circulating antibody. Like healthy tissue, we observe that mouse and human tumors are commonly surveyed by virus-specific memory CD8+ T cells. This was seen in a range of tumor types including traditionally ‘immune-privilege’ tissues such as glioblastoma. Given the described immunostimualtory functions of antiviral TRM in healthy tissue, we tested if we could leverage antiviral CD8+ T cells in tumors as an immunotherapy. Local delivery of adjuvant-free peptide derived from previously encountered viruses successfully reactivated antiviral T cells within melanoma and glioblastoma tumors. This arrested growth of checkpoint blockade-resistant and poorly immunogenic tumors in mice. Antiviral T cell reactivation triggered antigen presentation and cytotoxic pathways within the tumor, activating T cells, dendritic cells and natural killer cells. Viral peptide treatment of ex vivo human tumors demonstrated upregulation of immune activation gene expression profiles similar to those observed in mice. Lastly, viral peptide therapy renders resistant mouse tumors susceptible to PD-L1 blockade. Thus, re-stimulating known antiviral immunity may provide a novel therapeutic approach for a broad range of tumors.
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- 2020
37. On the performance of directional communications in ultra-dense networks
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Xiaoyun Wu, Zhang Yi, Mohammad Mamunur Rashid, Rath Vannithamby, Arvind Merwaday, and Clark Chen
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Wireless network ,Computer science ,business.industry ,Mobile broadband ,020206 networking & telecommunications ,Throughput ,02 engineering and technology ,Spectral efficiency ,Base station ,Interference (communication) ,0202 electrical engineering, electronic engineering, information engineering ,Cellular network ,Electronic engineering ,Network performance ,Mobile telephony ,business ,Computer network - Abstract
Extreme densification of base stations is imminent in the next generation of cellular networks to meet the exponentially increasing demand for mobile data traffic. In such ultra-dense networks (UDNs), the remarkably high inter-cell interference can reduce or even negate the densification gain. On the other hand, directional communications can significantly bring down the interference levels in UDNs. Hence, it is of importance to evaluate the network performance of UDNs with directional communications. Through Monte Carlo simulations, this paper analyzes the characteristics of coverage probability, area spectral efficiency (ASE), and per-user throughput with respect to extreme network densification. Our simulation results show that directional communications can deliver significantly higher network performance with tens of times higher ASE when compared to non-directional communications in UDNs.
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- 2017
38. Incidence and predictors of 30-day readmission for patients discharged home after craniotomy for malignant supratentorial tumors in California (1995-2010)
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Logan P, Marcus, Brandon A, McCutcheon, Abraham, Noorbakhsh, Ralitza P, Parina, David D, Gonda, Clark, Chen, David C, Chang, and Bob S, Carter
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Adult ,Male ,Incidence ,Supratentorial Neoplasms ,Health Care Costs ,Middle Aged ,Patient Readmission ,California ,Patient Discharge ,Risk Factors ,Humans ,Female ,Craniotomy ,Aged - Abstract
Hospital readmission within 30 days of discharge is a major contributor to the high cost of health care in the US and is also a major indicator of patient care quality. The purpose of this study was to investigate the incidence, causes, and predictors of 30-day readmission following craniotomy for malignant supratentorial tumor resection.The longitudinal California Office of Statewide Health PlanningDevelopment inpatient-discharge administrative database is a data set that consists of 100% of all inpatient hospitalizations within the state of California and allows each patient to be followed throughout multiple inpatient hospital stays, across multiple institutions, and over multiple years (from 1995 to 2010). This database was used to identify patients who underwent a craniotomy for resection of primary malignant brain tumors. Causes for unplanned 30-day readmission were identified by principle ICD-9 diagnosis code and multivariate analysis was used to determine the independent effect of various patient factors on 30-day readmissions.A total of 18,506 patients received a craniotomy for the treatment of primary malignant brain tumors within the state of California between 1995 and 2010. Four hundred ten patients (2.2%) died during the index surgical admission, 13,586 patients (73.4%) were discharged home, and 4510 patients (24.4%) were transferred to another facility. Among patients discharged home, 1790 patients (13.2%) were readmitted at least once within 30 days of discharge, with 27% of readmissions occurring at a different hospital than the initial surgical institution. The most common reasons for readmission were new onset seizure and convulsive disorder (20.9%), surgical infection of the CNS (14.5%), and new onset of a motor deficit (12.8%). Medi-Cal beneficiaries were at increased odds for readmission relative to privately insured patients (OR 1.52, 95% CI 1.20-1.93). Patients with a history of prior myocardial infarction were at an increased risk of readmission (OR 1.64, 95% CI 1.06-2.54) as were patients who developed hydrocephalus (OR 1.58, 95% CI 1.20-2.07) or venous complications during index surgical admission (OR 3.88, 95% CI 1.84-8.18).Using administrative data, this study demonstrates a baseline glioma surgery 30-day readmission rate of 13.2% in California for patients who are initially discharged home. This paper highlights the medical histories, perioperative complications, and patient demographic groups that are at an increased risk for readmission within 30 days of home discharge. An analysis of conditions present on readmission that were not present at the index surgical admission, such as infection and seizures, suggests that some readmissions may be preventable. Discharge planning strategies aimed at reducing readmission rates in neurosurgical practice should focus on patient groups at high risk for readmission and comprehensive discharge planning protocols should be implemented to specifically target the mitigation of potentially preventable conditions that are highly associated with readmission.
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- 2014
39. SWAN: End-to-end orchestration for cloud network and WAN
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Clark Chen, Xin Huang, and Haiyang Qian
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business.industry ,Computer science ,Quality of service ,ComputerSystemsOrganization_COMPUTER-COMMUNICATIONNETWORKS ,Network virtualization ,Wireless WAN ,Cloud computing ,Virtualization ,computer.software_genre ,Wide area application services ,Wide area network ,business ,Virtual network ,computer ,Computer network - Abstract
Networking Virtualization abstracts the underlying networking away from the tenants in multiple-tenant cloud data center (DC). Thus the tenants can apply their policies, manage their address space, group and migrate their VMs independently. The DCs are interconnected by Wide Area Network (WAN). To provide virtual network across multiple DCs is a desirable feature. The bandwidth of WAN is, however, a scarce resource. And the different encapsulation of packet in the DC and WAN causes the mechanism to handle Quality of Service (QoS) are different. In this paper, we leverage Software-Define Networking to achieve network virtualization in the DC orchestrated by OpenStack and convey the application level QoS from the DC to the WAN. We design an end-to-end DC and WAN orchestration architecture to extend the network virtualization across multiple DCs with application level QoS awareness and consistency.
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- 2013
40. Metrology of micro-step height structures using 3D scatterometry in 4x-nm advance DRAM
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Clark Chen, Zhengquan Tan, ZhiQing Xu, Mason Duan, Elvis Wang, Sungchul Yoo, Calvin Hsu, Elsie Yu, and Qiong-Yan Yuan
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Optics ,Materials science ,Etching (microfabrication) ,business.industry ,Chemical-mechanical planarization ,Process control ,Process window ,Nitride ,business ,Critical dimension ,Dram ,Metrology - Abstract
As DRAM design rules scale below 4Xnm, controlling the micro-step height caused by the etching process after patterning becomes more critical because it affects the post Chemical Mechanical Planarization (CMP) process window and furthermore affects yield. In this study, the latest Multi-Azimuth angle capability of Scatterometry Critical Dimension (SCD) was used to analyze the model of the micro-step height of nitride. SCD results were verified with Atomic Force Microscope (AFM) measurements.
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- 2011
41. Multi-user MIMO and adaptive frequency reuse for next-generation mobile broadband networks
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Nageen Himayat, Hua Yang, Guangjie Li, Hongming Zheng, Clark Chen, Minnie Ho, Hongmei Sun, Yuval Lomnitz, Vladimir Kravtsov, Hujun Yin, Yang-Seok Choi, Shanshan Zheng, Qinghua Li, and Shilpa Talwar
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Orthogonal frequency-division multiplexing ,business.industry ,Computer science ,Broadband networks ,Mobile broadband ,IMT Advanced ,MIMO ,Mobile computing ,Throughput ,Spectral efficiency ,Communications system ,Multi-user MIMO ,Frequency reuse ,Next-generation network ,Telecommunications link ,The Internet ,Mobile telephony ,business ,Computer network - Abstract
In order to meet the constantly increasing demand for ubiquitous, mobile access to the internet, next-generation mobile broadband communications systems based on OFDMA, such as IEEE 802.16m, require a significant performance increase over previous generation systems, such as IEEE 802.16e-2005, particularly in cell-edge and average spectral efficiency [2]. In this paper, we address the downlink adaptive frequency reuse (AFR) and multi-user MIMO (MU-MIMO) techniques which are considered to be the most promising candidates for meeting the requirements on cell-edge and average spectral efficiency of next-generation mobile broadband systems.
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- 2009
42. Towards a Rapid-Turnaround Low-Depth Unbiased Metagenomics Sequencing Workflow on the Illumina Platforms
- Author
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Winston Lian Chye Koh, Si En Poh, Chun Kiat Lee, Tim Hon Man Chan, Gabriel Yan, Kiat Whye Kong, Lalita Lau, Wai Yip Thomas Lee, Clark Cheng, Shawn Hoon, and Yiqi Seow
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metagenomic sequencing ,host depletion ,DNA/RNA library preparation ,liquid biopsy ,infectious disease ,Technology ,Biology (General) ,QH301-705.5 - Abstract
Unbiased metagenomic sequencing is conceptually well-suited for first-line diagnosis as all known and unknown infectious entities can be detected, but costs, turnaround time and human background reads in complex biofluids, such as plasma, hinder widespread deployment. Separate preparations of DNA and RNA also increases costs. In this study, we developed a rapid unbiased metagenomics next-generation sequencing (mNGS) workflow with a human background depletion method (HostEL) and a combined DNA/RNA library preparation kit (AmpRE) to address this issue. We enriched and detected bacterial and fungal standards spiked in plasma at physiological levels with low-depth sequencing (
- Published
- 2023
- Full Text
- View/download PDF
43. All-trans retinoic acids induce differentiation and sensitize a radioresistant breast cancer cells to chemotherapy.
- Author
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Yunwen Yan, Zhen Li, Xiang Xu, Clark Chen, Wei Wei, Ming Fan, Xufeng Chen, Jian Jian Li, Yuan Wang, and Jiaoti Huang
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BREAST tumor treatment ,TRETINOIN ,ALLERGY desensitization ,ALTERNATIVE medicine ,BIOLOGICAL assay ,BREAST tumors ,CELL differentiation ,CELL physiology ,FLOW cytometry ,HEMATOPOIETIC stem cells ,MEDICAL needs assessment ,NATURAL immunity ,RADIOTHERAPY ,RESEARCH funding ,SURVIVAL ,T-test (Statistics) ,DATA analysis ,TREATMENT effectiveness ,THERAPEUTICS - Abstract
Background: Radiotherapy is of critical importance in the treatment of breast cancer. However, not all patients derive therapeutic benefit and some breast cancers are resistant to the treatment, and are thus evidenced with prospective distant metastatic spread and local recurrence. In this study, we investigated the potential therapeutic effects of all-trans retinoic acid (ATRA) on radiation-resistant breast cancer cells and the associated invasiveness. Methods: The MCF7/C6 cells with gained radiation resistance after a long term treatment with fractionated ionizing radiation were derived from human breast cancer MCF7 cell line, and are enriched with cells expressing putative breast cancer stem cell biomarker CD44
+ /CD24-/low /ALDH+ . The enhanced invasiveness and the acquired resistances to chemotherapeutic treatments of MCF7/C6 cells were measured, and potential effects of all-trans retinoic acid (ATRA) on the induction of differentiation, invasion and migration, and on the sensitivities to chemotherapies in MCF7/C6 cells were investigated. Results: MCF7/C6 cells are with enrichment of cancer stem-cell like cells with positive staining of CD44+ /CD24-/low , OCT3/4 and NANOG. MCF7/C6 cells showed an increased tumoregensis potential and enhanced aggressiveness of invasion and migration. Treatment with ATRA induces the differentiation in MCF7/C6 cells, resulting in reduced invasiveness and migration, and increased sensitivity to Epirubincin treatment. Conclusion: Our study suggests a potential clinic impact for ATRA as a chemotherapeutic agent for treatment of therapy-resistant breast cancer especially for the metastatic lesions. The study also provides a rationale for ATRA as a sensitizer of Epirubincin, a first-line treatment option for breast cancer patients. [ABSTRACT FROM AUTHOR]- Published
- 2016
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44. Co-Channel Interference Mitigation in MIMO-OFDM System
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He, Chunwei, primary, Liu, Fuqiang, additional, Yang, Hua, additional, Clark, Chen, additional, Sun, Hongmei, additional, Wu, May, additional, and Zhang, Ji, additional
- Published
- 2007
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- View/download PDF
45. A nonlinear analysis of the relationship between rainfall and runoff for extreme floods
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Clark Chen-Kun Liu and Wilfried Brutsaert
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Mathematical optimization ,Chebyshev polynomials ,Watershed ,Volterra series ,Linear model ,Orthogonal functions ,Hydrograph ,Physics::Geophysics ,Runoff model ,Nonlinear system ,Applied mathematics ,Physics::Atmospheric and Oceanic Physics ,Water Science and Technology ,Mathematics - Abstract
The watershed response to heavy rainfall was considered as a hereditary process. A nonlinear system model was developed in terms of a Volterra integral series of the first kind, which satisfies the principle of dissipation of hereditary action as well as the requirement of time invariance. A workable and practical method was developed to compute optimal response functions or kernels of the two-term truncated Volterra series. A Galerkin-type method was used, whereby the kernels were approximated by an orthogonal function expansion in terms of Chebyshev polynomials. The kernels evaluated from historical data for the Cowanesque watershed in the Chemung River basin were tested by reconstituting the hydrograph of an unrelated and unusual flood event caused by tropical storm Agnes of June 1972. It was found that the nonlinear watershed model yields a better prediction of the hydrograph of an exceptional flood than the linear model. The performance of both nonlinear and linear models is sensitive to the assumed value of the rainfall loss rate.
- Published
- 1978
46. A nonlinear analysis of the relationship between rainfall and runoff for extreme floods
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Liu, Clark Chen-Kun, primary and Brutsaert, Wilfried, additional
- Published
- 1978
- Full Text
- View/download PDF
47. Shunting for hydrocephalus: analysis of techniques and failure patterns.
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Nigim, Fares, Critchlow, Jonathan F., Schneider, Benjamin E., Clark Chen, and Kasper, Ekkehard M.
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- *
HYDROCEPHALUS , *CEREBROSPINAL fluid , *LAPAROSCOPIC surgery , *SURGICAL anastomosis , *LENGTH of stay in hospitals , *URINARY incontinence diagnosis - Abstract
Background Hydrocephalus is characterized by ventricular dilatation because of progressive accumulation of cerebrospinal fluid. Normal pressure hydrocephalus (NPH) affects a subset of patients representing a reversible clinical triad of gait disturbance, urinary incontinence, and dementia with normal cerebrospinal fluid pressure and composition. Various shunting procedures have been used for treatment, but techniques and outcomes remain under debate. The objective of this study was to evaluate the clinical outcomes of 232 patients with and without NPH after the first-time Ventriculoperitoneal shunt placement and assessed patterns of failure between December 2004 and December 2012. Results Mean age was 54.7 y in non-NPH and 71.9 y in NPH patients. We used open technique in 34.3% and laparoscopic technique in 65.7% of NPH patients and 32.7% and 67.3% of the non-NPH patients, respectively. A total of 36 of 232 patients displayed shunt failure, 16.4% in NPH and 15.2% in non-NPH patients. Twenty-three of 155 patients failed after laparoscopic and 13 of 77 failed after open placement. Proximal shunt failure was more frequent in the non-NPH cohort. Distal failures accounted for 13 of 232 cases, and the difference between laparoscopic (six of 155) and open failures (seven of 77) was profound, but not between NPH- and non-NPH patients. Conclusions Shunt failures are related to the placement method. Non-NPH patients showed more proximal failures. NPH patients showed fewer proximal failures. Less distal failures were observed after laparoscopic ventriculoperitoneal shunt placement without significant differences between NPH and non-NPH patients. Beyond this, laparoscopic surgery carries distinct advantages such as shorter operating room times and hospital stays, which should translate into less use of pain medications, earlier mobilization, and a lower incidence of ileus. [ABSTRACT FROM AUTHOR]
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- 2014
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48. DNA Replication Restart in Archaea
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Floriane Delpech, Hannu Myllykallio, Roxane Lestini, Laboratoire d'Optique et Biosciences (LOB), École polytechnique (X)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Clark Chen, and Roura, Denis
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Genetics ,[SDV.GEN]Life Sciences [q-bio]/Genetics ,Cell ,DNA replication ,[SDV.GEN] Life Sciences [q-bio]/Genetics ,Biology ,biology.organism_classification ,medicine.anatomical_structure ,Three-domain system ,[SDV.BBM] Life Sciences [q-bio]/Biochemistry, Molecular Biology ,medicine ,[SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology ,Bacteria ,Archaea - Abstract
International audience; One fundamental challenge of cells is to accurately copy their genetic material for cell prolif‐eration. This task is performed by core machineries considered conserved in all three domainsof life: bacteria, archaea and eukaryotes...
- Published
- 2015
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