Browsing by Author "Chen, Yong"

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    Intrahepatic HBV DNA as a predictor of antivirus treatment efficacy in HBeAg-positive chronic hepatitis B patients
    (Baishideng Publishing Group, 2007-05-28) Lu, Hai-Ying; Zhuang, Li-Wei; Yu, Yan-Yan; Ivan, Hadad; Si, Chong-Wen; Zeng, Zheng; Li, Jun; Hou, Dong-Ming; Chen, Xin-Yue; Han, Zhong-Hou; Chen, Yong; Department of Medicine, IU School of Medicine
    AIM: To evaluate the effect of antiviral agents on intrahepatic HBV DNA in HBeAg-positive chronic hepatitis B patients. METHODS: Seventy-one patients received treatment with lamivudine, interferon alpha (IFN-alpha 2b) or sequential therapy with lamivudine-IFN-alpha 2b for 48 wk. All subjects were followed up for 24 wk. Serum and intrahepatic HBV DNA were measured quantitatively by PCR. HBV genotypes were analyzed by PCR-RFLP. RESULTS: At the end of treatment, the intrahepatic HBV DNA level in 71 patients decreased from a mean of (6.1 +/- 1.0) log10 to (4.9 +/- 1.4) log10. Further, a larger decrease was seen in the intrahepatic HBV DNA level in patients with HBeAg seroconversion. Intrahepatic HBV DNA level (before and after treatment) was not significantly affected by the patients' HBV genotype, or by the probability of virological flare after treatment. CONCLUSION: Intrahepatic HBV DNA can be effectively lowered by antiviral agents and is a significant marker for monitoring antivirus treatment. Low intrahepatic HBV DNA level may achieve better efficacy of antivirus treatment.
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    Learning competing risks across multiple hospitals: one-shot distributed algorithms
    (Oxford University Press, 2024) Zhang, Dazheng; Tong, Jiayi; Jing, Naimin; Yang, Yuchen; Luo, Chongliang; Lu, Yiwen; Christakis, Dimitri A.; Güthe, Diana; Hornig, Mady; Kelleher, Kelly J.; Morse, Keith E.; Rogerson, Colin M.; Divers, Jasmin; Carroll, Raymond J.; Forrest, Christopher B.; Chen, Yong; Pediatrics, School of Medicine
    Objectives: To characterize the complex interplay between multiple clinical conditions in a time-to-event analysis framework using data from multiple hospitals, we developed two novel one-shot distributed algorithms for competing risk models (ODACoR). By applying our algorithms to the EHR data from eight national children's hospitals, we quantified the impacts of a wide range of risk factors on the risk of post-acute sequelae of SARS-COV-2 (PASC) among children and adolescents. Materials and methods: Our ODACoR algorithms are effectively executed due to their devised simplicity and communication efficiency. We evaluated our algorithms via extensive simulation studies as applications to quantification of the impacts of risk factors for PASC among children and adolescents using data from eight children's hospitals including the Children's Hospital of Philadelphia, Cincinnati Children's Hospital Medical Center, Children's Hospital of Colorado covering over 6.5 million pediatric patients. The accuracy of the estimation was assessed by comparing the results from our ODACoR algorithms with the estimators derived from the meta-analysis and the pooled data. Results: The meta-analysis estimator showed a high relative bias (∼40%) when the clinical condition is relatively rare (∼0.5%), whereas ODACoR algorithms exhibited a substantially lower relative bias (∼0.2%). The estimated effects from our ODACoR algorithms were identical on par with the estimates from the pooled data, suggesting the high reliability of our federated learning algorithms. In contrast, the meta-analysis estimate failed to identify risk factors such as age, gender, chronic conditions history, and obesity, compared to the pooled data. Discussion: Our proposed ODACoR algorithms are communication-efficient, highly accurate, and suitable to characterize the complex interplay between multiple clinical conditions. Conclusion: Our study demonstrates that our ODACoR algorithms are communication-efficient and can be widely applicable for analyzing multiple clinical conditions in a time-to-event analysis framework.
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    Real-world Effectiveness of BNT162b2 Against Infection and Severe Diseases in Children and Adolescent
    (medRxiv, 2023-11-13) Wu, Qiong; Tong, Jiayi; Zhang, Bingyu; Zhang, Dazheng; Chen, Jiajie; Lei, Yuqing; Lu, Yiwen; Wang, Yudong; Li, Lu; Shen, Yishan; Xu, Jie; Bailey, L. Charles; Bian, Jiang; Christakis, Dimitri A.; Fitzgerald, Megan L.; Hirabayashi, Kathryn; Jhaveri, Ravi; Khaitan, Alka; Lyu, Tianchen; Rao, Suchitra; Razzaghi, Hanieh; Schwenk, Hayden T.; Wang, Fei; Witvliet, Margot I.; Tchetgen Tchetgen, Eric J.; Morris, Jeffrey S.; Forrest, Christopher B.; Chen, Yong; Pediatrics, School of Medicine
    Background: The efficacy of the BNT162b2 vaccine in pediatrics was assessed by randomized trials before the Omicron variant's emergence. The long-term durability of vaccine protection in this population during the Omicron period remains limited. Objective: To assess the effectiveness of BNT162b2 in preventing infection and severe diseases with various strains of the SARS-CoV-2 virus in previously uninfected children and adolescents. Design: Comparative effectiveness research accounting for underreported vaccination in three study cohorts: adolescents (12 to 20 years) during the Delta phase, children (5 to 11 years) and adolescents (12 to 20 years) during the Omicron phase. Setting: A national collaboration of pediatric health systems (PEDSnet). Participants: 77,392 adolescents (45,007 vaccinated) in the Delta phase, 111,539 children (50,398 vaccinated) and 56,080 adolescents (21,180 vaccinated) in the Omicron period. Exposures: First dose of the BNT162b2 vaccine vs. no receipt of COVID-19 vaccine. Measurements: Outcomes of interest include documented infection, COVID-19 illness severity, admission to an intensive care unit (ICU), and cardiac complications. The effectiveness was reported as (1-relative risk)*100% with confounders balanced via propensity score stratification. Results: During the Delta period, the estimated effectiveness of BNT162b2 vaccine was 98.4% (95% CI, 98.1 to 98.7) against documented infection among adolescents, with no significant waning after receipt of the first dose. An analysis of cardiac complications did not find an increased risk after vaccination. During the Omicron period, the effectiveness against documented infection among children was estimated to be 74.3% (95% CI, 72.2 to 76.2). Higher levels of effectiveness were observed against moderate or severe COVID-19 (75.5%, 95% CI, 69.0 to 81.0) and ICU admission with COVID-19 (84.9%, 95% CI, 64.8 to 93.5). Among adolescents, the effectiveness against documented Omicron infection was 85.5% (95% CI, 83.8 to 87.1), with 84.8% (95% CI, 77.3 to 89.9) against moderate or severe COVID-19, and 91.5% (95% CI, 69.5 to 97.6)) against ICU admission with COVID-19. The effectiveness of the BNT162b2 vaccine against the Omicron variant declined after 4 months following the first dose and then stabilized. The analysis revealed a lower risk of cardiac complications in the vaccinated group during the Omicron variant period. Limitations: Observational study design and potentially undocumented infection. Conclusions: Our study suggests that BNT162b2 was effective for various COVID-19-related outcomes in children and adolescents during the Delta and Omicron periods, and there is some evidence of waning effectiveness over time.
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    A self-cured glass-ionomer cement with improved antibacterial function and hardness
    (Wiley, 2020) Chen, Yong; Caneli, Gulsah; Almousa, Rashed; Hill, Kayla; Na, Sungsoo; Anderson, Gregory G.; Xie, Dong; Biology, School of Science
    A novel antimicrobial dental self-cured glass-ionomer cement has been developed and evaluated. Alumina filler particles were covalently coated with an antibacterial polymer and blended into a self-cured glass-ionomer cement formulation. Surface hardness and bacterial viability were used to evaluate the modified cements. Results showed that the modified cements exhibited a significantly enhanced antibacterial activity along with improved surface hardness. Effects of antibacterial moiety content, alumina particle size and loading, and total filler content were investigated. It was found that increasing antibacterial moiety content, particle size and loading, and total filler content generally increased surface hardness. Increasing antibacterial moiety, filler loading and total filler content increased antibacterial activity. On the other hand, increasing particle size showed a negative impact on antibacterial activity. The leaching tests indicate no cytotoxicity produced from the modified cements to both bacteria and 3T3 mouse fibroblast cells.
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    Targeting MLL1 H3K4 methyltransferase activity in mixed-lineage leukemia
    (Elsevier, 2014-01-23) Cao, Fang; Townsend, Elizabeth C.; Karatas, Hacer; Xu, Jing; Li, Li; Lee, Shirley; Liu, Liu; Chen, Yong; Ouillette, Peter; Zhu, Jidong; Hess, Jay L.; Atadja, Peter; Lei, Ming; Qin, Zhaohui; Malek, Sami; Wang, Shaomeng; Dou, Yali; IU School of Medicine
    Here we report a comprehensive characterization of our recently developed inhibitor MM-401 that targets the MLL1 H3K4 methyltransferase activity. MM-401 is able to specifically inhibit MLL1 activity by blocking MLL1-WDR5 interaction and thus the complex assembly. This targeting strategy does not affect other mixed-lineage leukemia (MLL) family histone methyltransferases (HMTs), revealing a unique regulatory feature for the MLL1 complex. Using MM-401 and its enantiomer control MM-NC-401, we show that inhibiting MLL1 methyltransferase activity specifically blocks proliferation of MLL cells by inducing cell-cycle arrest, apoptosis, and myeloid differentiation without general toxicity to normal bone marrow cells or non-MLL cells. More importantly, transcriptome analyses show that MM-401 induces changes in gene expression similar to those of MLL1 deletion, supporting a predominant role of MLL1 activity in regulating MLL1-dependent leukemia transcription program. We envision broad applications for MM-401 in basic and translational research.