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Nakamura G, Chai N, Park S, Chiang N, Lin Z, Chiu H, Fong R, Yan D, Kim J, Zhang J, Lee WP, Estevez A, Coons M, Xu M, Lupardus P, Balazs M, Swem LR. An in vivo human-plasmablast enrichment technique allows rapid identification of therapeutic influenza A antibodies. Cell Host Microbe 2014; 14:93-103. [PMID: 23870317 DOI: 10.1016/j.chom.2013.06.004] [Citation(s) in RCA: 135] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Revised: 05/21/2013] [Accepted: 06/03/2013] [Indexed: 12/01/2022]
Abstract
Recent advances enabling the cloning of human immunoglobulin G genes have proven effective for discovering monoclonal antibodies with therapeutic potential. However, these antibody-discovery methods are often arduous and identify only a few candidates from numerous antibody-secreting plasma cells or plasmablasts. We describe an in vivo enrichment technique that identifies broadly neutralizing human antibodies with high frequency. For this technique, human peripheral blood mononuclear cells from vaccinated donors are activated and enriched in an antigen-specific manner for the production of numerous antigen-specific plasmablasts. Using this technology, we identified four broadly neutralizing influenza A antibodies by screening only 840 human antibodies. Two of these antibodies neutralize every influenza A human isolate tested and perform better than the current anti-influenza A therapeutic, oseltamivir, in treating severe influenza infection in mice and ferrets. Furthermore, these antibodies elicit robust in vivo synergism when combined with oseltamivir, thus highlighting treatment strategies that could benefit influenza-infected patients.
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Research Support, Non-U.S. Gov't |
11 |
135 |
2
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Wang HW, Chai N, Wang P, Hu S, Dou W, Umulis D, Wang LV, Sturek M, Lucht R, Cheng JX. Label-free bond-selective imaging by listening to vibrationally excited molecules. PHYSICAL REVIEW LETTERS 2011; 106:238106. [PMID: 21770549 PMCID: PMC3398792 DOI: 10.1103/physrevlett.106.238106] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2010] [Revised: 05/07/2011] [Indexed: 05/19/2023]
Abstract
We report the realization of vibrational photoacoustic (VPA) microscopy using optical excitation of molecular overtone vibration and acoustic detection of the resultant pressure transients. Our approach eliminates the tissue scattering problem encountered in near-infrared spectroscopy and enables depth-resolved signal collection. The 2nd overtone of the CH bond stretch around 8300 cm(-1), where blood interference is minimal, is excited. We demonstrate 3D VPA imaging of lipid-rich atherosclerotic plaques by excitation from the artery lumen, and lipid storage in live Drosophila larvae, with millimeter scale penetration depth [corrected].
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Research Support, N.I.H., Extramural |
14 |
94 |
3
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Simmons G, Rennekamp AJ, Chai N, Vandenberghe LH, Riley JL, Bates P. Folate receptor alpha and caveolae are not required for Ebola virus glycoprotein-mediated viral infection. J Virol 2004; 77:13433-8. [PMID: 14645601 PMCID: PMC296046 DOI: 10.1128/jvi.77.24.13433-13438.2003] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Folate receptor alpha (FRalpha) has been described as a factor involved in mediating Ebola virus entry into cells (6). Furthermore, it was suggested that interaction with FRalpha results in internalization and subsequent viral ingress into the cytoplasm via caveolae (9). Descriptions of cellular receptors for Ebola virus and its entry mechanisms are of fundamental importance, particularly with the advent of vectors bearing Ebola virus glycoprotein (GP) being utilized for gene transfer into cell types such as airway epithelial cells. Thus, the ability of FRalpha to mediate efficient entry of viral pseudotypes carrying GP was investigated. We identified cell lines and primary cell types such as macrophages that were readily infected by GP pseudotypes despite lacking detectable surface FRalpha, indicating that this receptor is not essential for Ebola virus infection. Furthermore, we find that T-cell lines stably expressing FRalpha are not infectible, suggesting that FRalpha is also not sufficient to mediate entry. T-cell lines lack caveolae, the predominant route of FRalpha-mediated folate metabolism. However, the coexpression of FRalpha with caveolin-1, the major structural protein of caveolae, was not able to rescue infectivity in a T-cell line. In addition, other cell types lacking caveolae are fully infectible by GP pseudotypes. Finally, a panel of ligands to and soluble analogues of FRalpha were unable to inhibit infection on a range of cell lines, questioning the role of FRalpha as an important factor for Ebola virus entry.
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Research Support, U.S. Gov't, P.H.S. |
21 |
87 |
4
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Chai N, Patel Y, Jacobson K, McMahon J, McMahon A, Rappolee DA. FGF is an essential regulator of the fifth cell division in preimplantation mouse embryos. Dev Biol 1998; 198:105-15. [PMID: 9640334 DOI: 10.1006/dbio.1997.8858] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Fibroblast growth factor (FGF) signaling is required prior to gastrulation in the mouse embryo. To test for the spatial and temporal requirements of FGF signaling, a dominant negative FGF receptor (dnFGFR) was used to make transgenic mouse embryos. In mosaic embryos, cell division ceased at the fifth cell division in all cells that expressed the mutant receptor, but cell death did not increase. After the fifth cell division, the progeny of unaltered cells and cells expressing lacZ continued to accumulate at the same rate, suggesting that the FGF requirement is cell autonomous. In mosaic embryos, lacZ, but not dnFGFR expression was detected in mitotic trophoblasts adjacent to the ICM. Conversely, dnFGFR-expressing extraembryonic ectoderm cells were detected at the abembryonic pole in postmitotic cells. In blastocysts expressing the dnFGFR in all cells, the morphology appeared normal and inner cell masses (ICMs) formed, but resultant embryos had only one-third the number of cells as control embryos. In these blastocysts, cell division had also ceased at the fifth cell division, but cavitation, a concurrent morphogenetic event, initiated and progressed normally. To test for the continuing requirement of FGF, FGFR-3 was overexpressed in all cells and resulted in an increase in cell numbers after the fifth cell cycle. In a model for postimplantation development, addition of FGF-4 to blastocyst outgrowths increased the number of extraembryonic ectoderm cells, suggesting a continuing role for FGF. Thus, FGF signaling induces the cell division of embryonic and extraembryonic cells in the preimplantation mouse embryo starting at the fifth cell division. The signal requirement for FGF is cell autonomous, but is not required to prevent cell death. This provides the first evidence for the necessity of a growth factor before implantation.
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84 |
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Chai N, Bates P. Na+/H+ exchanger type 1 is a receptor for pathogenic subgroup J avian leukosis virus. Proc Natl Acad Sci U S A 2006; 103:5531-6. [PMID: 16567631 PMCID: PMC1459389 DOI: 10.1073/pnas.0509785103] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Subgroup J avian leukosis virus (ALV-J) is a recently identified avian oncogenic retrovirus responsible for severe economic losses worldwide. In contrast with the other ALV subgroups, ALV-J predominantly induces myeloid leukosis in meat-type chickens. Despite significant homology with the other ALV subgroups across most of the genome, the envelope protein of ALV-J (EnvJ) shares low homology with the others. Pathogenicity and myeloid leukosis induction map to the env gene of ALV-J. A chimeric protein composed of the surface domain of EnvJ fused to the constant region of a rabbit IgG and mass spectrometry were used to identify the chicken Na(+)/H(+) exchanger type 1 (chNHE1) as a binding protein for ALV-J. Flow cytometry analysis and coprecipitation experiments demonstrated a specific interaction between EnvJ and chNHE1. When introduced into nonpermissive human 293T cells and quail QT6 cells, chNHE1 conferred susceptibility to EnvJ-mediated infection. Furthermore, 293T cells expressing chNHE1 fused with 293T cells expressing EnvJ in a low-pH-dependent manner. Together, these data identify chNHE1 as a cellular receptor for the highly pathogenic ALV-J.
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Research Support, N.I.H., Extramural |
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75 |
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Chai N, Swem LR, Reichelt M, Chen-Harris H, Luis E, Park S, Fouts A, Lupardus P, Wu TD, Li O, McBride J, Lawrence M, Xu M, Tan MW. Two Escape Mechanisms of Influenza A Virus to a Broadly Neutralizing Stalk-Binding Antibody. PLoS Pathog 2016; 12:e1005702. [PMID: 27351973 PMCID: PMC4924800 DOI: 10.1371/journal.ppat.1005702] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 05/23/2016] [Indexed: 12/22/2022] Open
Abstract
Broadly neutralizing antibodies targeting the stalk region of influenza A virus (IAV) hemagglutinin (HA) are effective in blocking virus infection both in vitro and in vivo. The highly conserved epitopes recognized by these antibodies are critical for the membrane fusion function of HA and therefore less likely to be permissive for virus mutational escape. Here we report three resistant viruses of the A/Perth/16/2009 strain that were selected in the presence of a broadly neutralizing stalk-binding antibody. The three resistant viruses harbor three different mutations in the HA stalk: (1) Gln387Lys; (2) Asp391Tyr; (3) Asp391Gly. The Gln387Lys mutation completely abolishes binding of the antibody to the HA stalk epitope. The other two mutations, Asp391Tyr and Asp391Gly, do not affect antibody binding at neutral pH and only slightly reduce binding at low pH. Interestingly, they enhance the fusion ability of the HA, representing a novel mechanism that allows productive membrane fusion even in the presence of antibody and hence virus escape from antibody neutralization. Therefore, these mutations illustrate two different resistance mechanisms used by IAV to escape broadly neutralizing stalk-binding antibodies. Compared to the wild type virus, the resistant viruses release fewer progeny viral particles during replication and are more sensitive to Tamiflu, suggesting reduced viral fitness. IAV causes seasonal epidemics and periodic pandemics that result in significant morbidity and mortality worldwide. The effectiveness of influenza vaccines is highly variable because the virus evolves rapidly and causes antibody mismatch. The use of neuraminidase inhibitors, the current standard of treatment for IAV infection, is limited by their lack of efficacy beyond 48 hours of symptom onset and by the emergence of drug resistant viruses. Recently, broadly neutralizing antibodies targeting the conserved stalk region of IAV HA have been discovered. These antibodies are able to block the infection of many or even all IAV strains, and hold great promise as the next generation of anti-flu treatment. Nonetheless, virus resistance to these antibodies has not been thoroughly studied despite the common view that broadly neutralizing stalk-binding antibodies are less permissive for mutational escape due to the functional importance of their highly conserved epitopes. In this study, we isolated three resistant viruses to a stalk-binding antibody that was previously shown to neutralize all IAV tested. Interestingly, they use two distinct mechanisms to escape the antibody, abolishing antibody binding or enhancing membrane fusion. Our study emphasizes the need to consider novel escape mechanisms when studying virus resistance to broadly neutralizing stalk-binding antibodies.
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Journal Article |
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68 |
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Chai N, Swem LR, Park S, Nakamura G, Chiang N, Estevez A, Fong R, Kamen L, Kho E, Reichelt M, Lin Z, Chiu H, Skippington E, Modrusan Z, Stinson J, Xu M, Lupardus P, Ciferri C, Tan MW. A broadly protective therapeutic antibody against influenza B virus with two mechanisms of action. Nat Commun 2017; 8:14234. [PMID: 28102191 PMCID: PMC5253702 DOI: 10.1038/ncomms14234] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 12/12/2016] [Indexed: 01/12/2023] Open
Abstract
Influenza B virus (IBV) causes annual influenza epidemics around the world. Here we use an in vivo plasmablast enrichment technique to isolate a human monoclonal antibody, 46B8 that neutralizes all IBVs tested in vitro and protects mice against lethal challenge of all IBVs tested when administered 72 h post infection. 46B8 demonstrates a superior therapeutic benefit over Tamiflu and has an additive antiviral effect in combination with Tamiflu. 46B8 binds to a conserved epitope in the vestigial esterase domain of hemagglutinin (HA) and blocks HA-mediated membrane fusion. After passage of the B/Brisbane/60/2008 virus in the presence of 46B8, we isolated three resistant clones, all harbouring the same mutation (Ser301Phe) in HA that abolishes 46B8 binding to HA at low pH. Interestingly, 46B8 is still able to protect mice against lethal challenge of the mutant viruses, possibly owing to its ability to mediate antibody-dependent cellular cytotoxicity (ADCC). Influenza B virus (IBV) co-circulates with influenza A virus to cause annual epidemics. Here, Chai et al. isolate a human monoclonal antibody that binds to a conserved epitope in the viral HA protein, neutralizes IBV strains in vitro, and protects mice against IBV infection.
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Journal Article |
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49 |
8
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Liu X, Zhou Q, Guo Z, Liu P, Shen L, Chai N, Qian B, Cai Y, Wang W, Yin Z, Zhang H, Zheng X, Zhang Z. A self-balancing circuit centered on MoOsm1 kinase governs adaptive responses to host-derived ROS in Magnaporthe oryzae. eLife 2020; 9:61605. [PMID: 33275098 PMCID: PMC7717906 DOI: 10.7554/elife.61605] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 11/26/2020] [Indexed: 12/16/2022] Open
Abstract
The production of reactive oxygen species (ROS) is a ubiquitous defense response in plants. Adapted pathogens evolved mechanisms to counteract the deleterious effects of host-derived ROS and promote infection. How plant pathogens regulate this elaborate response against ROS burst remains unclear. Using the rice blast fungus Magnaporthe oryzae, we uncovered a self-balancing circuit controlling response to ROS in planta and virulence. During infection, ROS induces phosphorylation of the high osmolarity glycerol pathway kinase MoOsm1 and its nuclear translocation. There, MoOsm1 phosphorylates transcription factor MoAtf1 and dissociates MoAtf1-MoTup1 complex. This releases MoTup1-mediated transcriptional repression on oxidoreduction-pathway genes and activates the transcription of MoPtp1/2 protein phosphatases. In turn, MoPtp1/2 dephosphorylate MoOsm1, restoring the circuit to its initial state. Balanced interactions among proteins centered on MoOsm1 provide a means to counter host-derived ROS. Our findings thereby reveal new insights into how M. oryzae utilizes a phosphor-regulatory circuitry to face plant immunity during infection.
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Research Support, Non-U.S. Gov't |
5 |
49 |
9
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Comizzoli P, Mermillod P, Cognié Y, Chai N, Legendre X, Mauge R. Successful in vitro production of embryos in the red deer (Cervus elaphus) and the sika deer (Cervus nippon). Theriogenology 2001; 55:649-59. [PMID: 11233790 DOI: 10.1016/s0093-691x(01)00433-2] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The aim of our study was to define the conditions for IVM and IVF of oocytes in 2 common deer species as models for endangered related subspecies. Immature oocytes were recovered during the breeding season from postmortem ovaries (red deer) or by repeated laparoscopic follicular aspiration (sika deer). Oocytes were cultured for 24 h in IVM medium supplemented with EGF or FSH and follicular fluid. Stag semen was collected by electroejaculation (both species) or by epididymal flushing (red deer) and cryopreserved. For IVF, oocytes were exposed to different concentrations of thawed spermatozoa in a modified Tyrode albumin lactate pyruvate medium supplemented with 20% (v/v) estrus sheep serum for 18 h. After IVF, presumptive zygotes were allowed to develop in vitro for 7 days in synthetic oviduct fluid (SOF) supplemented with fetal calf serum (10%, v/v). In both species, the presence of ovine FSH and follicular fluid improved the in vitro maturation rate. In the sika deer, the optimal sperm concentration for IVF was 10(6)/mL and some fertilized oocytes reached the early morula stage (20 to 25 cells). In the red deer, after IVF with ejaculated or epididymal spermatozoa (2.0 x 10(6)/mL), 20% of zygotes developed to the blastocyst stage (50 to 80 cells).
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Comparative Study |
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48 |
10
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Chai N, Liu JF, Xue YX, Yang C, Yan W, Wang HM, Luo YX, Shi HS, Wang JS, Bao YP, Meng SQ, Ding ZB, Wang XY, Lu L. Delayed noradrenergic activation in the dorsal hippocampus promotes the long-term persistence of extinguished fear. Neuropsychopharmacology 2014; 39:1933-45. [PMID: 24553734 PMCID: PMC4059903 DOI: 10.1038/npp.2014.42] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Revised: 02/08/2014] [Accepted: 02/10/2014] [Indexed: 01/18/2023]
Abstract
Fear extinction has been extensively studied, but little is known about the molecular processes that underlie the persistence of extinction long-term memory (LTM). We found that microinfusion of norepinephrine (NE) into the CA1 area of the dorsal hippocampus during the early phase (0 h) after extinction enhanced extinction LTM at 2 and 14 days after extinction. Intra-CA1 infusion of NE during the late phase (12 h) after extinction selectively promoted extinction LTM at 14 days after extinction that was blocked by the β-receptor antagonist propranolol, protein kinase A (PKA) inhibitor Rp-cAMPS, and protein synthesis inhibitors anisomycin and emetine. The phosphorylation levels of PKA, cyclic adenosine monophosphate response element-binding protein (CREB), GluR1, and the membrane GluR1 level were increased by NE during the late phase after extinction that was also blocked by propranolol and Rp-cAMPS. These results suggest that the enhancement of extinction LTM persistence induced by NE requires the activation of the β-receptor/PKA/CREB signaling pathway and membrane GluR1 trafficking. Moreover, extinction increased the phosphorylation levels of Erk1/2, CREB, and GluR1, and the membrane GluR1 level during the late phase, and anisomycin/emetine alone disrupted the persistence of extinction LTM, indicating that the persistence of extinction LTM requires late-phase protein synthesis in the CA1. Propranolol and Rp-cAMPS did not completely disrupt the persistence of extinction LTM, suggesting that another β-receptor/PKA-independent mechanism underlies the persistence of extinction LTM. Altogether, our results showed that enhancing hippocampal noradrenergic activity during the late phase after extinction selectively promotes the persistence of extinction LTM.
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research-article |
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36 |
11
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Wu G, Chai N, Kim I, Klein AS, Jordan SC. Monoclonal anti-interleukin-6 receptor antibody attenuates donor-specific antibody responses in a mouse model of allosensitization. Transpl Immunol 2013; 28:138-43. [PMID: 23562586 DOI: 10.1016/j.trim.2013.03.003] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Revised: 03/22/2013] [Accepted: 03/25/2013] [Indexed: 12/26/2022]
Abstract
Interleukin 6 is an immune regulatory cytokine that impacts the development and maturation of T-cell, B-cell, and antibody producing plasma cells. A monoclonal antibody to the IL-6R (Tocilizumab®) was recently approved by the FDA for treatment of rheumatoid arthritis. Although anti-IL-6R anitbodies can reduce autoantibody levels in human disease, the use of anti-IL-6R for alloantibody suppression has not been examined. Here, we report on our experience with a mousenized rat-anti-mouse IL-6R (mMR16-1) for attenuating donor-specific antibody (DSA) responses. C57BL/6 mice were sensitized with skin allografts from a HLA.A2 transgenic mouse, and treated with intraperitoneal injections of mMR16-1 or control antibody. DSA responses were monitored weekly for 5weeks by measurement of serum anti-HLA.A2 antibodies in a flow cytometric antibody binding assay. Results show that mMR16-1 significantly reduced DSA IgM, IgG2a and IgG1 responses, respectively, while normalizing serum amyloid A (SAA), an acute phase reactant induced by IL-6 (p<0.01 vs. control). mMR16-1 injections increased mononuclear cell apoptosis in the spleens, as detected by annexin V staining and TUNEL. In conclusion, anti-IL6R attenuates de novo DSA responses and suppresses inflammatory markers (SAA). The data indicate that antibody therapy targeting the IL-6/IL-6R pathway may serve as a strategy to suppress DSA generation.
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Research Support, Non-U.S. Gov't |
12 |
33 |
12
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Xu S, Xie B, Song M, Yu L, Wang L, An C, Zhu Q, Han K, Zhao X, Zhang R, Dong L, Chai N, Gao Y, Zhang Q, Wang X. High Prevalence of Mild Cognitive Impairment in the Elderly: A Community-Based Study in Four Cities of the Hebei Province, China. Neuroepidemiology 2014; 42:123-30. [DOI: 10.1159/000357374] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Accepted: 11/18/2013] [Indexed: 11/19/2022] Open
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Yang C, Liu JF, Chai BS, Fang Q, Chai N, Zhao LY, Xue YX, Luo YX, Jian M, Han Y, Shi HS, Lu L, Wu P, Wang JS. Stress within a restricted time window selectively affects the persistence of long-term memory. PLoS One 2013; 8:e59075. [PMID: 23544051 PMCID: PMC3609809 DOI: 10.1371/journal.pone.0059075] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Accepted: 02/11/2013] [Indexed: 12/02/2022] Open
Abstract
The effects of stress on emotional memory are distinct and depend on the stages of memory. Memory undergoes consolidation and reconsolidation after acquisition and retrieval, respectively. Stress facilitates the consolidation but disrupts the reconsolidation of emotional memory. Previous research on the effects of stress on memory have focused on long-term memory (LTM) formation (tested 24 h later), but the effects of stress on the persistence of LTM (tested at least 1 week later) are unclear. Recent findings indicated that the persistence of LTM requires late-phase protein synthesis in the dorsal hippocampus. The present study investigated the effect of stress (i.e., cold water stress) during the late phase after the acquisition and retrieval of contextual fear memory in rats. We found that stress and corticosterone administration during the late phase (12 h) after acquisition, referred to as late consolidation, selectively enhanced the persistence of LTM, whereas stress during the late phase (12 h) after retrieval, referred to as late reconsolidation, selectively disrupted the restabilized persistence of LTM. Moreover, the effects of stress on the persistence of LTM were blocked by the corticosterone synthesis inhibitor metyrapone, which was administered before stress, suggesting that the glucocorticoid system is involved in the effects of stress on the persistence of LTM. We conclude that stress within a restricted time window after acquisition or retrieval selectively affects the persistence of LTM and depends on the glucocorticoid system.
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Research Support, Non-U.S. Gov't |
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27 |
14
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Nie Z, Yin J, Zhou H, Chai N, Chen B, Zhang Y, Qu K, Shen G, Ma H, Li Y, Zhao J, Zhang X. Layered and Pb-Free Organic-Inorganic Perovskite Materials for Ultraviolet Photoresponse: (010)-Oriented (CH 3NH 3) 2MnCl 4 Thin Film. ACS APPLIED MATERIALS & INTERFACES 2016; 8:28187-28193. [PMID: 27686006 DOI: 10.1021/acsami.6b08962] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Organic-inorganic lead perovskite materials show impressive performance in photovoltaics, photodetectors, light-emitting diodes, lasers, sensors, medical imaging devices, and other applications. Although organic-inorganic lead perovskites have shown good performance in numerous fields, they contain toxic Pb, which is expected to cause environmental pollution in future large-scale applications. Thus, the photoelectric properties of Pb-free organic-inorganic perovskite materials should be developed and studied. In this paper, we report on the photoresponse of Pb-free organic-inorganic hybrid manganese perovskite (CH3NH3)2MnCl4. To the best of our knowledge, this study demonstrates the first time that organic-inorganic hybrid manganese perovskites are used for this type of application. We found that the solution-processed MA2MnCl4 thin film tends to be oriented along the b-axis direction on the TiO2 surface. The evident photoresponse of the FTO/TiO2/MA2MnCl4/carbon electrode devices was observed under 10-30 Hz flashlight frequencies and a 330 nm light beam. This simple, green, and low-cost photoresponsive device is beneficial for the future industrial production of optical recorders and optical memory devices.
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15
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Kuehner JP, Naik SV, Kulatilaka WD, Chai N, Laurendeau NM, Lucht RP, Scully MO, Roy S, Patnaik AK, Gord JR. Perturbative theory and modeling of electronic-resonance-enhanced coherent anti-Stokes Raman scattering spectroscopy of nitric oxide. J Chem Phys 2008; 128:174308. [DOI: 10.1063/1.2909554] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Chai N, Chang HE, Nicolas E, Gudima S, Chang J, Taylor J. Assembly of hepatitis B virus envelope proteins onto a lentivirus pseudotype that infects primary human hepatocytes. J Virol 2007; 81:10897-904. [PMID: 17670822 PMCID: PMC2045538 DOI: 10.1128/jvi.00959-07] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
This study demonstrates that the envelope proteins of hepatitis B virus (HBV) could be incorporated into the lipid membrane of lentivirus pseudotype particles. The assembly procedure was initiated by the transfection of 293T cells with three plasmids: (i) a human immunodeficiency virus (HIV) packaging construct, (ii) a transfer plasmid expressing a reporter gene, and (iii) a plasmid expressing large (L), middle (M), and small (S) HBV envelope proteins. After 2 days, hepatitis B surface antigen and the antigenic forms of L, M, and S were detected at the cell surface by flow cytometry. Also, virus particles that were able to infect cultured primary human hepatocytes (PHH) were released. Under optimal conditions, 50% of PHH could be infected. In addition, the susceptibility of PHH and the resistance of other cell types to the pseudotype particles were similar to those observed for HBV and hepatitis delta virus (HDV), which shares the same L, M, and S. Furthermore, the infection of PHH by the pseudotype was sensitive to known inhibitors of HBV and HDV entry. These findings of specific and efficient infection of hepatocytes could be applicable to liver-specific gene therapy and may help clarify the attachment and entry mechanism used by HBV and HDV.
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Research Support, Non-U.S. Gov't |
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Lin Z, Chiang NY, Chai N, Seshasayee D, Lee WP, Balazs M, Nakamura G, Swem LR. In vivo antigen-driven plasmablast enrichment in combination with antigen-specific cell sorting to facilitate the isolation of rare monoclonal antibodies from human B cells. Nat Protoc 2014; 9:1563-77. [PMID: 24901740 DOI: 10.1038/nprot.2014.104] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The ability to rapidly generate large panels of antigen-specific human antibodies in a rodent would enable the efficient discovery of novel therapeutically useful antibodies. We have developed a system wherein human antigen-specific antibody-secreting plasmablasts can be enriched in vivo, in a severe combined immunodeficient (SCID)/beige mouse host. The antigen-specific plasmablasts can then be sorted by flow cytometry, enabling single-cell cloning and expression of fully human immunoglobulin-G. By using this technique, we have generated four broadly reactive anti-influenza A antibodies. Therefore, the method described here is useful for the identification of rare functional antibodies. This protocol takes ∼1 month to complete, from the time of human vaccination to the cloning of heavy- and light-chain genes. For additional small-scale transient expression, purification and binding analysis, the protocol would take an additional month.
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Journal Article |
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Yin J, Liu X, Fan L, Wei J, He G, Shi S, Guo J, Yuan C, Chai N, Wang C, Cui J, Wang X, Zhou H, Tian D. Synthesis, crystal structure, absorption properties, photoelectric behavior of organic-inorganic hybrid (CH3
NH3
)2
CoCl4. Appl Organomet Chem 2019. [DOI: 10.1002/aoc.4795] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Yin J, Di F, Guo J, Zhang K, Xu W, Wang Y, Shi S, Chai N, Chu C, Wei J, Li W, Shao X, Pu X, Zhang D, Ren X, Wang J, Zhao J, Zhang X, Wei X, Wang F, Zhou H. Tuning Ni-Foam into NiOOH/FeOOH Heterostructures toward Superior Water Oxidation Catalyst via Three-Step Strategy. ACS OMEGA 2018; 3:11009-11017. [PMID: 31459211 PMCID: PMC6645584 DOI: 10.1021/acsomega.8b01143] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2018] [Accepted: 08/13/2018] [Indexed: 05/24/2023]
Abstract
Splitting of water into hydrogen and oxygen has become a strategic research topic. In the two semi-reactions of water splitting, water oxidation is preferred to the four-electron-transfer process with a higher overpotential (η) and is the decisive step in water splitting. Therefore, efficient water oxidation catalysts must be developed. IrO x and RuO x catalysts are currently the most efficient catalysts in water oxidation. However, the limited reserve and high prices of precious metals, such as Ir and Ru, limit future large-scale industrial production of water oxidation catalysts. In this study, we tune inert Ni-foam into highly active NiOOH/FeOOH heterostructures as water oxidation catalysts via three-step strategy (surface acid-treating, electroplating, and electrooxidation). NiOOH/FeOOH heterostructures as water oxidation catalysts only require η of 257 mV to reach a current density of 10 mA cm-2, which is superior to that of IrO2/Ni-foam (280 mV). The high electrochemically active surface area (72.50 cm2) and roughness factor demonstrate abundant interfaces in NiOOH/FeOOH heterostructures, thus accelerating water oxidation activity. The small value (4.8 Ω cm2) of charge transfer resistance (R ct) indicate that fast electronic exchange occurs between NiOOH/FeOOH heterostructures catalyst and reaction of water oxidation. Hydrogen-to-oxygen volume ratios (approximately 2:1) indicate an almost overall water splitting by the double-electrode system. Faraday efficiency of H2 or O2 is close to 90% at 2:1 hydrogen-to-oxygen volume ratio. NiOOH/FeOOH heterostructures exhibit good stability. The results provide significance in fundamental research and practical applications in solar water splitting, artificial photoelectrochemical cells, and electrocatalysts.
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research-article |
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Mamo L, Nouel JP, Robert J, Chai N, Houdart R. Use of radioactive bleomycin to detect malignant intracranial tumors. Comparative study with technetium-99m in 104 cases. J Neurosurg 1973; 39:735-41. [PMID: 4128173 DOI: 10.3171/jns.1973.39.6.0735] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
✓ A new isotopic method for the detection of cerebral tumors using labeled bleomycin is described. In a series of 104 patients, bleomycin was found superior to technetium-99m for the diagnosis of intracranial metastatic lesions; in 50% of the cases, bleomycin revealed metastases undetected by the Tc-99m, particularly in the posterior fossa. This method also provides valuable data for the differentiation of gliomas from metastases.
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Comparative Study |
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Chai N, Gudima S, Chang J, Taylor J. Immunoadhesins containing pre-S domains of hepatitis B virus large envelope protein are secreted and inhibit virus infection. J Virol 2007; 81:4912-8. [PMID: 17329331 PMCID: PMC1900235 DOI: 10.1128/jvi.02865-06] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Hepatitis B virus (HBV) replication produces three envelope proteins (L, M, and S) that have a common C terminus. L, the largest, contains a domain, pre-S1, not present on M. Similarly M contains a domain, pre-S2, not present on S. The pre-S1 region has important functions in the HBV life cycle. Thus, as an approach to studying these roles, the pre-S1 and/or pre-S2 sequences of HBV (serotype adw2, genotype A) were expressed as N-terminal fusions to the Fc domain of a rabbit immunoglobulin G chain. Such proteins, known as immunoadhesins (IA), were highly expressed following transfection of cultured cells and, when the pre-S1 region was present, >80% were secreted. The IA were myristoylated at a glycine penultimate to the N terminus, although mutation studies showed that this modification was not needed for secretion. As few as 30 amino acids from the N terminus of pre-S1 were both necessary and sufficient to drive secretion of IA. Even expression of pre-S1 plus pre-S2, in the absence of an immunoglobulin chain, led to efficient secretion. Overall, these studies demonstrate an unexpected ability of the N terminus of pre-S1 to promote protein secretion. In addition, some of these secreted IA, at nanomolar concentrations, inhibited infection of primary human hepatocytes either by hepatitis delta virus (HDV), a subviral agent that uses HBV envelope proteins, or HBV. These IA have potential to be part of antiviral therapies against chronic HDV and HBV, and may help understand the attachment and entry mechanisms used by these important human pathogens.
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Research Support, Non-U.S. Gov't |
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Li L, Linghu E, Chai N, Li Z, Zou J, Du C, Wang X, Xiang J. Efficacy of triamcinolone-soaked polyglycolic acid sheet plus fully covered metal stent for preventing stricture formation after large esophageal endoscopic submucosal dissection. Dis Esophagus 2019; 32:5250776. [PMID: 30561608 DOI: 10.1093/dote/doy121] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Indexed: 12/11/2022]
Abstract
Esophageal stricture is a major problem for patients with large superficial esophageal squamous cell neoplasms (SESCNs) after endoscopic submucosal dissection (ESD). Although many measures could be used as prophylaxis for post-ESD strictures, a well-accepted method has not yet been established. We propose using a triamcinolone-soaked polyglycolic acid sheet plus fully covered metal stent (TS-PGA+FCMS) as a novel method to prevent stricture formation after large esophageal ESD. From June 2016 to May 2017, nine patients with SESCNs (≥3/4 of the esophageal circumference) who underwent TS-PGA+FCMS placement immediately after ESD and did not require additional surgical resection were enrolled in this case series. All stents were removed 4-6 weeks post-ESD. The sizes of mucosal defects in 9 patients were 3/4 (n = 1), 4/5 (n = 2), 1/1 (n = 6). The average size of resection was 90.0 mm (range: 60-140 mm). The incidence of stricture was 33.3% (3/9) of patients. No stricture occurred in 3 patients with noncircumferential resection, while stricture occurred in 50% (3/6) patients with circumferential resection. The median number of EBD sessions was 4 (range: 3-4 sessions). No adverse events or recurrences were observed during the median follow-up period of 15.2 months (range: 12-22 months). The TS-PGA+FCMS method is safe and may decrease the incidence of esophageal stricture and the number of EBD sessions after large esophageal ESD.
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Evaluation Study |
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Zhou H, Liu X, He G, Fan L, Shi S, Wei J, Xu W, Yuan C, Chai N, Chen B, Zhang Y, Zhang X, Zhao J, Wei X, Yin J, Tian D. Synthesis, Crystal Structure, UV-Vis Adsorption Properties, Photoelectric Behavior, and DFT Computational Study of All-Inorganic and Lead-Free Copper Halide Salt K 2Cu 2Cl 6. ACS OMEGA 2018; 3:14021-14026. [PMID: 31458097 PMCID: PMC6644466 DOI: 10.1021/acsomega.8b01337] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 09/11/2018] [Indexed: 06/09/2023]
Abstract
In this study, all-inorganic copper halide salt K2Cu2Cl6 single-crystal and thin films were prepared. The single-crystal diffraction data belonged to the monoclinic K2Cu2Cl6 (space group = P 2(1)/C, unit cell parameters of a = 4.0340 Å, b = 13.7987 Å, c = 8.7445 Å, α = 90.000, β = 97.123, and γ = 90.000). As far as we know, this is the first study of the copper halide salt K2Cu2Cl6 for optoelectronic applications. The band gap of K2Cu2Cl6 is calculated to be approximately 1.85 eV. A low-cost photodetector based on the K2Cu2Cl6 thin film was efficient under different monochromatic light from 330 to 390 nm with different chopping frequencies (1.33-30 Hz). Density functional theory (DFT) computational results indicate that the valence bands (VBs) and conduction bands (CBs) are shifted up in energy using the orbital-dependent correction to the DFT energy. Partial density of states reveals that the VBs and narrow CBs are derived from the hybrid orbitals of Cu2+ 3d and Cl- p, respectively.
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Zhang L, Qin R, Chai N, Wei H, Yang Y, Wang Y, Li FM, Zhang F. Optimum fertilizer application rate to ensure yield and decrease greenhouse gas emissions in rain-fed agriculture system of the Loess Plateau. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 823:153762. [PMID: 35151728 DOI: 10.1016/j.scitotenv.2022.153762] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 02/03/2022] [Accepted: 02/05/2022] [Indexed: 06/14/2023]
Abstract
Application of nitrogen (N) can increase the supply of N in soil and, in turn, can lead to higher yield-but also to large increase in emissions of greenhouse gases (GHGs) if applied in excess. To determine the optimum dose of N for maize planting system, we analysed the relationship between yield and emissions of GHGs at seven levels of N, namely 50, 100, 150, 200, 250, 300, and 350 kg ha-1, using the DNDC (denitrification decomposition) model and maize grown with and without mulching. The model simulated the following variables: maize production; emissions of carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4); global warming potential (GWP); and GHG intensity (GHGI). We used data from 1980 to 2013 for a rain-fed region of the Loess Plateau in north-western China and validated the DNDC model against data from field experiments. The model performed well in simulating yield and GHG emissions (Adj.R2 > 0.61). Under mulching, the average yield of maize was 3.6-12.2 t ha-1 and the partial factor productivity was 73.1-35.0 kg kg-1; and both of these were significantly higher 78%-236% than those in the crop without mulching. The emissions of CO2, N2O, and the GWP increased with the increase in the dose of N whereas CH4 emissions remained unaffected by the dose. Mulching increased yields significantly in the north-western region, and the GWP and GHGI were higher mainly in the central and north-western regions. The optimum dose of N for maize grown with mulching ranged between 150 kg ha-1 and 200 kg ha-1 and offers the best balance between higher yield and lower emissions. The optimum dose may promote the development of mulched maize and provide a reference standard for dryland agriculture in zones with similar climates elsewhere in the world.
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Chai N, Wu Y, Zhang M, Wu WB, Zhang H, Kong FW, Zhang Y. Remote intervention using smartphone for rural women suffering from premenstrual syndrome: A propensity score matched analysis. Medicine (Baltimore) 2018; 97:e11629. [PMID: 30024566 PMCID: PMC6086547 DOI: 10.1097/md.0000000000011629] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Timely treatment of premenstrual syndrome (PMS) is not always available for rural women, because the local medical resources are insufficient. The efficacy of remote intervention by smartphone on PMS has not been confirmed.A retrospective analysis was performed on rural PMS patients between January 2014 and December 2015. After a propensity score matched analysis, 60 patients were enrolled and evenly divided into remote group and outpatient group. Multidisciplinary therapy including cognitive-behavioral therapy (CBT), oral medication, and physical exercise education was used individually, in accordance with their symptoms evaluated by Daily Record of Severity of Problems (DRSP) questionnaire. Patients in remote group utilized WeChat software by smartphone for therapy guidance, while those in outpatient group attended face-to-face interview. Their DRSP scores in 5 new menstrual cycles after therapy were recorded. Then, they were followed up for 1 year.Total DRSP scores of the cases in both groups after initial intervention were less than those before therapy (P < .001), without group difference (P > .05). However, patients in remote group indicated a higher satisfactory rate than the outpatient group (P = .03). On the 1-year follow up, patients in both groups demonstrated similar DRSP scores (P = .07), but the satisfactory rate in remote group was encouragingly higher than that in the outpatient group (P = .02).The efficacy of remote intervention using smartphone on PMS is noninferior to traditional outpatient visits. Nevertheless, high-quality trials are needed.
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Observational Study |
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