33 results on '"Y. G. Peng"'
Search Results
2. [Clinical characteristics of 14 cases of neonatal tracheotomy in neonatal intensive care unit]
- Author
-
J W, Weng, J, Yu, F, Jin, Y G, Peng, J J, Zhou, Y, Chen, J, Zhang, and M Y, Hei
- Subjects
Male ,Intensive Care Units, Neonatal ,Infant, Newborn ,Humans ,Infant ,Female ,Tracheotomy ,Child ,Weight Gain ,Vocal Cord Paralysis ,Retrospective Studies - Published
- 2022
3. SARS-CoV-2 drives NLRP3 inflammasome activation in human microglia through spike protein
- Author
-
Eduardo A. Albornoz, Alberto A. Amarilla, Naphak Modhiran, Sandra Parker, Xaria X. Li, Danushka K. Wijesundara, Julio Aguado, Adriana Pliego Zamora, Christopher L. D. McMillan, Benjamin Liang, Nias Y. G. Peng, Julian D. J. Sng, Fatema Tuj Saima, Jenny N. Fung, John D. Lee, Devina Paramitha, Rhys Parry, Michael S. Avumegah, Ariel Isaacs, Martin W. Lo, Zaray Miranda-Chacon, Daniella Bradshaw, Constanza Salinas-Rebolledo, Niwanthi W. Rajapakse, Ernst J. Wolvetang, Trent P. Munro, Alejandro Rojas-Fernandez, Paul R. Young, Katryn J. Stacey, Alexander A. Khromykh, Keith J. Chappell, Daniel Watterson, and Trent M. Woodruff
- Subjects
Cellular and Molecular Neuroscience ,Psychiatry and Mental health ,Molecular Biology - Abstract
Coronavirus disease-2019 (COVID-19) is primarily a respiratory disease, however, an increasing number of reports indicate that SARS-CoV-2 infection can also cause severe neurological manifestations, including precipitating cases of probable Parkinson’s disease. As microglial NLRP3 inflammasome activation is a major driver of neurodegeneration, here we interrogated whether SARS-CoV-2 can promote microglial NLRP3 inflammasome activation. Using SARS-CoV-2 infection of transgenic mice expressing human angiotensin-converting enzyme 2 (hACE2) as a COVID-19 pre-clinical model, we established the presence of virus in the brain together with microglial activation and NLRP3 inflammasome upregulation in comparison to uninfected mice. Next, utilising a model of human monocyte-derived microglia, we identified that SARS-CoV-2 isolates can bind and enter human microglia in the absence of viral replication. This interaction of virus and microglia directly induced robust inflammasome activation, even in the absence of another priming signal. Mechanistically, we demonstrated that purified SARS-CoV-2 spike glycoprotein activated the NLRP3 inflammasome in LPS-primed microglia, in a ACE2-dependent manner. Spike protein also could prime the inflammasome in microglia through NF-κB signalling, allowing for activation through either ATP, nigericin or α-synuclein. Notably, SARS-CoV-2 and spike protein-mediated microglial inflammasome activation was significantly enhanced in the presence of α-synuclein fibrils and was entirely ablated by NLRP3-inhibition. Finally, we demonstrate SARS-CoV-2 infected hACE2 mice treated orally post-infection with the NLRP3 inhibitory drug MCC950, have significantly reduced microglial inflammasome activation, and increased survival in comparison with untreated SARS-CoV-2 infected mice. These results support a possible mechanism of microglial innate immune activation by SARS-CoV-2, which could explain the increased vulnerability to developing neurological symptoms akin to Parkinson’s disease in COVID-19 infected individuals, and a potential therapeutic avenue for intervention.
- Published
- 2022
4. Zika virus noncoding RNA suppresses apoptosis and is required for virus transmission by mosquitoes
- Author
-
Leon E. Hugo, Andrii Slonchak, Morgan E. Freney, Alexander A. Khromykh, Gregor J. Devine, Julian D. J. Sng, Yin Xiang Setoh, Andrew F. van den Hurk, Francisco J. Torres, Roy A. Hall, Sonja Hall-Mendelin, Nias Y. G. Peng, and Alberto A. Amarilla
- Subjects
Viral vectors ,0301 basic medicine ,RNA, Untranslated ,Science ,030106 microbiology ,General Physics and Astronomy ,Apoptosis ,Mosquito Vectors ,Aedes aegypti ,Virus Replication ,Virus-host interactions ,Article ,Non-coding RNAs ,General Biochemistry, Genetics and Molecular Biology ,Zika virus ,03 medical and health sciences ,Aedes ,Chlorocebus aethiops ,parasitic diseases ,Animals ,Humans ,RNA, Messenger ,lcsh:Science ,Vero Cells ,Gene ,Cells, Cultured ,Subgenomic mRNA ,Regulation of gene expression ,Multidisciplinary ,biology ,Zika Virus Infection ,fungi ,RNA ,Zika Virus ,General Chemistry ,biology.organism_classification ,Non-coding RNA ,Virology ,030104 developmental biology ,Gene Expression Regulation ,Vero cell ,Insect Proteins ,RNA, Viral ,lcsh:Q - Abstract
Flaviviruses, including Zika virus (ZIKV), utilise host mRNA degradation machinery to produce subgenomic flaviviral RNA (sfRNA). In mammalian hosts, this noncoding RNA facilitates replication and pathogenesis of flaviviruses by inhibiting IFN-signalling, whereas the function of sfRNA in mosquitoes remains largely elusive. Herein, we conduct a series of in vitro and in vivo experiments to define the role of ZIKV sfRNA in infected Aedes aegypti employing viruses deficient in production of sfRNA. We show that sfRNA-deficient viruses have reduced ability to disseminate and reach saliva, thus implicating the role for sfRNA in productive infection and transmission. We also demonstrate that production of sfRNA alters the expression of mosquito genes related to cell death pathways, and prevents apoptosis in mosquito tissues. Inhibition of apoptosis restored replication and transmission of sfRNA-deficient mutants. Hence, we propose anti-apoptotic activity of sfRNA as the mechanism defining its role in ZIKV transmission., The function on subgenomic flaviviral RNA (sfRNA) in the mosquito vector is not well understood. Here, Slonchak et al. show that sfRNA affects virus-induced apoptosis and dissemination of ZIKV in Aedes aegypti mosquitoes, suggesting a role of sfRNA in Zika virus replication and transmission.
- Published
- 2020
5. [Development of case report form based on clinical data interchange standards consortium on special diseases to promote the ecology construction of real-world data in China]
- Author
-
X X, Peng, J, Su, S Y, Cai, R L, Peng, Y G, Peng, X L, Ma, and X, Ni
- Subjects
Data Analysis ,China ,Humans - Abstract
Real world data (RWD) refers to the data generated in routine clinical practices, daily life, and real work environment and has been widely used in clinical or public health research. Still, issues related to the quality of RWD, such as incompleteness, inconsistency, and inaccuracy, would affect the validity of real-world research. To overcome the challenges due to the lack of standardization of real world source data, case report form based on clinical data interchange standards consortium (CDISC-CRF) on certain diseases was developed to promote the ecology construction of RWD based on the data standards set by the CDISC which has been widely used. Firstly, we described how to apply data standards to make up the gap between RWD and real world evidence. Then, the process was designed to build RWD ecology based on CDISC-CRF, in which the development technology of CDISC-CRF form is mainly introduced. Finally, the application prospect and significance of building real-world data based on disease-specific CDISC-CRF are described. It is believed that the present paper can provide a new idea for promoting the ecology construction of RWD in China.真实世界数据是指在日常医疗活动、生活与工作等环境下产生的数据。真实世界数据在临床与公共卫生研究中一直被广泛应用,但真实世界数据质量相关问题,如不完整性、不一致性和准确性等会影响真实世界研究的真实性。为了应对真实世界源数据缺乏标准化带来的挑战,本文基于当前被广泛应用的数据标准,即临床数据交换标准协会(CDISC)开发的CDISC标准开发了专病CDISC-病例报告表(CRF),以提高真实世界源数据标准化水平,助力我国真实世界数据生态建设。我们阐述了如何应用数据标准弥补真实世界数据到真实世界证据之间的裂痕;设计了基于专病CDISC-CRF建设真实世界数据生态的流程,重点介绍了CDISC-CRF表单的开发技术;并就基于专病CDISC-CRF建设真实世界数据的应用前景及意义进行了描述。.
- Published
- 2021
6. [Establishment of reference interval of vitamin A for Chinese children and adolescents based on expectation-maximization algorithm]
- Author
-
Y G, Peng, Z H, Wu, R H, Yan, and X X, Peng
- Subjects
Male ,China ,Motivation ,Cross-Sectional Studies ,Adolescent ,Child, Preschool ,Infant, Newborn ,Humans ,Infant ,Female ,Child ,Vitamin A ,Algorithms - Published
- 2021
7. Nature and impact of charge transfer to ground-state dications in atomic and molecular environments
- Author
-
C. Küstner-Wetekam, Y. G. Peng, Philipp Schmidt, L. Marder, Christian Ozga, H. Otto, Uwe Hergenhahn, X. Q. Hu, Arno Ehresmann, Andreas Hans, J. G. Wang, Clemens Richter, Yang-Le Wu, André Knie, Nicolas Sisourat, and Ch. Zindel
- Subjects
Physics ,Work (thermodynamics) ,Argon ,chemistry ,Homogeneous ,Chemical physics ,chemistry.chemical_element ,Molecule ,Charge (physics) ,Redistribution (chemistry) ,Ground state ,Direct process - Abstract
Charge transfer processes between weakly bound entities play an important role in various chemical and biological environments. In this combined experimental and theoretical work, we investigate the nature of charge-transfer processes in homogeneous atomic and heterogeneous atomic-molecular clusters. Our results reveal fundamentally different processes to be at play in pure argon clusters compared to mixed argon-nitrogen systems: We demonstrate that the former species decay via photon-mediated charge transfer while a nonradiative direct process is found dominant in the atomic-molecular cases. Our results are of general interest for studies on charge redistribution in more complex and biologically relevant samples where molecules are involved.
- Published
- 2021
8. A versatile reverse genetics platform for SARS-CoV-2 and other positive-strand RNA viruses
- Author
-
Daniel J. Rawle, Jessica J. Harrison, Nias Y. G. Peng, Julian D. J. Sng, Darwin J. Da Costa Guevara, Naphak Modhiran, Thuy T. Le, Benjamin Liang, David A. Muller, Fasséli Coulibaly, Joshua M. Deerain, Morgan E. Freney, Alberto A. Amarilla, Rhys Parry, Xiaohui Wang, Stacey T. M. Cheung, Daniel Watterson, Christopher L. D. McMillan, Jody Hobson-Peters, Yin Xiang Setoh, Jason M. Mackenzie, James R. Potter, Francisco J. Torres, Mark Bettington, Joshua M. Hardy, Alyssa T. Pyke, Roy A. Hall, Paul R. Young, Alexander A. Khromykh, Andreas Suhrbier, and Frederick Moore
- Subjects
0301 basic medicine ,Science ,viruses ,030106 microbiology ,General Physics and Astronomy ,Alphavirus ,Genome, Viral ,Virus-host interactions ,Virus Replication ,Polymerase Chain Reaction ,General Biochemistry, Genetics and Molecular Biology ,Virus ,Article ,03 medical and health sciences ,chemistry.chemical_compound ,Mice ,Viral Proteins ,Complementary DNA ,Chlorocebus aethiops ,Animals ,Humans ,Amino Acid Sequence ,Vero Cells ,Polymerase ,Furin ,Multidisciplinary ,biology ,Base Sequence ,SARS-CoV-2 ,RNA ,virus diseases ,General Chemistry ,biology.organism_classification ,Virology ,Reverse genetics ,Reverse Genetics ,030104 developmental biology ,Culicidae ,HEK293 Cells ,RAW 264.7 Cells ,chemistry ,Viral replication ,Mutation ,biology.protein ,NIH 3T3 Cells ,Receptors, Virus ,DNA - Abstract
The current COVID-19 pandemic is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We demonstrate that despite the large size of the viral RNA genome (~30 kb), infectious full-length cDNA is readily assembled in vitro by a circular polymerase extension reaction (CPER) methodology without the need for technically demanding intermediate steps. Overlapping cDNA fragments are generated from viral RNA and assembled together with a linker fragment containing CMV promoter into a circular full-length viral cDNA in a single reaction. Transfection of the circular cDNA into mammalian cells results in the recovery of infectious SARS-CoV-2 virus that exhibits properties comparable to the parental virus in vitro and in vivo. CPER is also used to generate insect-specific Casuarina virus with ~20 kb genome and the human pathogens Ross River virus (Alphavirus) and Norovirus (Calicivirus), with the latter from a clinical sample. Additionally, reporter and mutant viruses are generated and employed to study virus replication and virus-receptor interactions., Here the authors describe a simple reverse genetics method that relies on overlapping cDNA fragments for generation of positive-strand viruses including SARS-CoV-2 and characterize them in vitro and in vivo.
- Published
- 2021
9. Zika virus noncoding RNA cooperates with the viral protein NS5 to inhibit STAT1 phosphorylation and facilitate viral pathogenesis
- Author
-
Alberto A. Amarilla, Yin Xiang Setoh, Xiaohui Wang, Julian D. J. Sng, Julio Aguado, Nias Y. G. Peng, Rickyle Balea, Daniel Watterson, Andreas Suhrbier, Morgan E. Freney, Andrii Slonchak, Harman Kaur Chaggar, Ernst J. Wolvetang, Kexin Yan, Alexander A. Khromykh, and Francisco J. Torres
- Subjects
biology ,Viral protein ,Viral pathogenesis ,RNA ,medicine.disease_cause ,biology.organism_classification ,Non-coding RNA ,Virology ,Zika virus ,Flavivirus ,medicine ,biology.protein ,STAT1 ,Subgenomic mRNA - Abstract
Zika virus (ZIKV) is a re-emerging pathogenic flavivirus, which causes microcephaly in infants and poses a continuing threat to public health. ZIKV, like all other flaviviruses, produces highly abundant noncoding RNA known as subgenomic flaviviral RNA (sfRNA). Herein we utilized wild-type and mutant ZIKV defective in production of sfRNA to elucidate for the first time how production of sfRNA affects all aspects of ZIKV pathogenesis. We found that in mouse pregnancy model of infection sfRNA is required for trans-placental dissemination of ZIKV and subsequent infection of fetal brain. Using human brain organoids, we showed that sfRNA promotes apoptosis of neural progenitor cells leading to profound cytopathicity and disintegration of organoids. We also found by transcriptome profiling and gene network analysis that in infected human placental cells sfRNA inhibits multiple antiviral pathways and promotes apoptosis with STAT1 identified as a key shared factor linking these two interconnected sfRNA activities. We further showed for the first time that sfRNA inhibits phosphorylation and nuclear translocation of STAT1 by a novel mechanism which involves binding to and stabilizing viral protein NS5. This allows accumulation of NS5 at the levels required for efficient inhibition of STAT1 phosphorylation. Thus, we elucidated the molecular mechanism by which ZIKV sfRNA exerts its functions in vertebrate hosts and discovered a co-operation between viral noncoding RNA and a viral protein as a novel strategy employed by viruses to counteract antiviral responses.
- Published
- 2021
10. Determinants of Zika virus host tropism uncovered by deep mutational scanning
- Author
-
Jessica J. Harrison, Jesse D. Bloom, Eri Nakayama, Bing Tang, Daniel Watterson, Faith Elizabeth Nanyonga, Natalie A. Prow, Julio Carrera, Thom Cuddihy, Roy A. Hall, Naphak Modhiran, Andreas Suhrbier, Jason M. Mackenzie, Morgan E. Freney, Rebecca E. Griffiths, Francisco J. Torres, Shinya Ogawa, Andrii Slonchak, Alberto A. Amarilla, Jody Hobson-Peters, Justin J. Cooper-White, Nias Y. G. Peng, Yin Xiang Setoh, Parthiban Periasamy, Paul R. Young, Ernst J. Wolvetang, Alexander A. Khromykh, Setoh, Yin Xiang, Amarilla, Alberto A, Peng, Nias YG, Griffiths, Rebecca E, Prow, Natalie A, and Khromykh, Alexander A
- Subjects
Microbiology (medical) ,Aedes ,0303 health sciences ,biology ,030306 microbiology ,viruses ,Immunology ,Host tropism ,Cell Biology ,biology.organism_classification ,high-throughput screening ,Applied Microbiology and Biotechnology ,Microbiology ,Virology ,Deep sequencing ,Virus ,virology ,Zika virus ,03 medical and health sciences ,Viral replication ,Viral evolution ,Genetics ,Tissue tropism ,030304 developmental biology - Abstract
Arboviruses cycle between, and replicate in, both invertebrate and vertebrate hosts, which for Zika virus (ZIKV) involves Aedes mosquitoes and primates 1 . The viral determinants required for replication in such obligate hosts are under strong purifying selection during natural virus evolution, making it challenging to resolve which determinants are optimal for viral fitness in each host. Herein we describe a deep mutational scanning (DMS) strategy 2–5 whereby a viral cDNA library was constructed containing all codon substitutions in the C-terminal 204 amino acids of ZIKV envelope protein (E). The cDNA library was transfected into C6/36 (Aedes) and Vero (primate) cells, with subsequent deep sequencing and computational analyses of recovered viruses showing that substitutions K316Q and S461G, or Q350L and T397S, conferred substantial replicative advantages in mosquito and primate cells, respectively. A 316Q/461G virus was constructed and shown to be replication-defective in mammalian cells due to severely compromised virus particle formation and secretion. The 316Q/461G virus was also highly attenuated in human brain organoids, and illustrated utility as a vaccine in mice. This approach can thus imitate evolutionary selection in a matter of days and identify amino acids key to the regulation of virus replication in specific host environments. Refereed/Peer-reviewed
- Published
- 2019
11. The distinguishing NS5-M114V mutation in American Zika virus isolates has negligible impacts on virus replication and transmission potential
- Author
-
Nias Y. G. Peng, Alberto A. Amarilla, Leon E. Hugo, Naphak Modhiran, Julian D. J. Sng, Andrii Slonchak, Daniel Watterson, Yin Xiang Setoh, and Alexander A. Khromykh
- Subjects
Zika Virus Infection ,Public Health, Environmental and Occupational Health ,Interferon-alpha ,Interferon-beta ,Mosquito Vectors ,Zika Virus ,Viral Nonstructural Proteins ,Virus Replication ,United States ,Mice ,Infectious Diseases ,Aedes ,Mutation ,Animals - Abstract
During 2015–2016, outbreaks of Zika virus (ZIKV) occurred in Southeast Asia and the Americas. Most ZIKV infections in humans are asymptomatic, while clinical manifestation is usually a self-limiting febrile disease with maculopapular rash. However, ZIKV is capable of inducing a range of severe neurological complications collectively described as congenital Zika syndrome (CZS). Notably, the scale and magnitude of outbreaks in Southeast Asia were significantly smaller compared to those in the Americas. Sequence comparison between epidemic-associated ZIKV strains from Southeast Asia with those from the Americas revealed a methionine to valine substitution at residue position 114 of the NS5 protein (NS5-M114V) in all the American isolates. Using an American isolate of ZIKV (Natal), we investigated the impact of NS5-M114V mutation on virus replication in cells, virulence in interferon (IFN) α/β receptor knockout (Ifnar-/-) mice, as well as replication and transmission potential in Aedes aegypti mosquitoes. We demonstrated that NS5-M114V mutation had insignificant effect on ZIKV replication efficiency in cells, its ability to degrade STAT2, and virulence in vivo, albeit viremia was slightly prolonged in mice. Furthermore, NS5-M114V mutation decreased mosquito infection and dissemination rates but had no effect on virus secretion into the saliva. Taken together, our findings support the notion that NS5-M114V mutation is unlikely to be a major determinant for virus replication and transmission potential.
- Published
- 2022
12. An Optimized High-Throughput Immuno-Plaque Assay for SARS-CoV-2
- Author
-
Alberto A. Amarilla, Naphak Modhiran, Yin Xiang Setoh, Nias Y. G. Peng, Julian D. J. Sng, Benjamin Liang, Christopher L. D. McMillan, Morgan E. Freney, Stacey T. M. Cheung, Keith J. Chappell, Alexander A. Khromykh, Paul R. Young, and Daniel Watterson
- Subjects
Microbiology (medical) ,2019-20 coronavirus outbreak ,Coronavirus disease 2019 (COVID-19) ,coronaviruses ,viruses ,Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ,lcsh:QR1-502 ,Biology ,Immunofluorescence ,Microbiology ,lcsh:Microbiology ,Neutralization ,03 medical and health sciences ,Methods ,medicine ,skin and connective tissue diseases ,030304 developmental biology ,viral quantification ,Virus quantification ,0303 health sciences ,medicine.diagnostic_test ,SARS-CoV-2 ,030306 microbiology ,Virology ,respiratory tract diseases ,immuno-plaque assay (iPA) ,biology.protein ,Antibody - Abstract
Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has been identified as the causative agent of coronavirus disease 2019 and is capable of human-to-human transmission and rapid global spread. The rapid emergence and global spread of SARS-CoV-2 has encouraged the establishment of a rapid, sensitive, and reliable viral detection and quantification methodology. Here, we present an alternative assay, termed immuno-plaque assay (iPA), which utilizes a combination of plaque assay and immunofluorescence techniques. We have extensively optimized the conditions for SARS-CoV-2 infection and demonstrated the great flexibility of iPA detection using several antibodies and dual-probing with two distinct epitope-specific antibodies. In addition, we showed that iPA could be utilized for ultra-high-throughput viral titration and neutralization assay within 24 h and is amenable to a 384-well format. These advantages will significantly accelerate SARS-CoV-2 research outcomes during this pandemic period.
- Published
- 2021
13. [Visual outcome of cataract surgery and its influencing factors in China]
- Author
-
J J, Feng, L, Yao, L, An, H Y, Zhang, Y G, Peng, L L, Zhan, W, Shi, and X, Xu
- Subjects
Aged, 80 and over ,Male ,China ,Phacoemulsification ,Postoperative Complications ,Treatment Outcome ,Case-Control Studies ,Humans ,Female ,Cataract Extraction ,Middle Aged ,Cataract ,Aged - Published
- 2021
14. [Epidemic characteristics of hand, foot and mouth disease (HFMD) and the lag effect of average daily temperature on the epidemic of HFMD in Beijing]
- Author
-
K, Li, Z H, Wu, G T, Liu, H T, Li, H Z, Wang, and Y G, Peng
- Subjects
Male ,Beijing ,Child, Preschool ,Incidence ,Temperature ,Humans ,Female ,Seasons ,Child ,Hand, Foot and Mouth Disease - Published
- 2020
15. Zika Virus sfRNA Plays an Essential Role in the Infection of Insects and Mammals
- Author
-
Nias Y. G. Peng, Yin Xiang Setoh, Andreas Suhrbier, Andrew F. van den Hurk, Ernst J. Wolvetang, Kexin Yan, Francisco J. Torres, Alexander A. Khromykh, Leon E. Hugo, Alberto A. Amarilla, Gregor J. Devine, Morgan E. Freney, Sonja Hall-Mendelin, Harman Kaur Chaggar, and Andrii Slonchak
- Subjects
Untranslated region ,foetal brain infection ,apoptosis ,RNA ,lcsh:A ,Biology ,subgenomic flavivirus RNA ,Virology ,Virus ,Zika virus ,Viral replication ,RNA interference ,Interferon ,medicine ,type I interferon ,lcsh:General Works ,Gene ,medicine.drug ,Subgenomic mRNA - Abstract
Similar to other flaviviruses, Zika virus (ZIKV) produces abundant subgenomic flavivirus RNA (sfRNA) derived from the 3’ untranslated region. The molecular mechanisms that determine the functions of sfRNA are currently not completely understood. Here, we created ZIKV mutants deficient in sfRNA production and employed them to investigate the role of this RNA in virus interactions with mammalian and insect hosts. We found that in mosquitoes, sfRNA facilitates virus replication and is required for ZIKV dissemination into saliva and virus transmission. The production of sfRNA was found to have no effect on the RNAi pathway, but instead downregulated the expression of genes involved in the regulation of apoptosis. The terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) of histological sections from infected mosquitoes confirmed that sfRNA prevents the apoptotic death of infected cells, thus identifying inhibition of apoptosis as a novel mechanism of sfRNA action in mosquitoes. We also found that sfRNA facilitates ZIKV replication in mammalian cells, mice, and human brain organoids. Moreover, ZIKV mutants deficient in sfRNA production were unable to form plaques, cause the death of human brain organoids, or establish infection in the mouse foetal brain. We then found that the proviral activity of sfRNA in mammalian cells relies on its ability to suppress type I interferon signalling. We showed that this is achieved via the inhibition of phosphorylation and the nuclear translocation of STAT1. In addition, we found that the production of sfRNA in the ZIKV infection of human brain organoids is associated with the suppression of multiple genes involved in brain development, indicating that sfRNA can be involved in the disruption of brain development associated with ZIKV infection.
- Published
- 2020
16. CCR2 plays a protective role in rocio virus–induced encephalitis by promoting macrophage infiltration into the brain
- Author
-
Naphak Modhiran, Mario Luis Garcia de Figueiredo, Victor Hugo Aquino, David F. Colón, Silvia Elena Sánchez Mendoza, Leonardo J. Galvão-Lima, Amanda C. Desiderá, Alexander A. Khromykh, Cleide Lúcia Araújo Silva, Helda Liz Alfonso, Richard L Spinieli, Nilton Nascimento Santos-Junior, Yin Xiang Setoh, Djalma S. Lima-Junior, Amanda Cristina Trabuco, João Paulo Mesquita Luiz, Sandra L. Balero Penharvel Martins, Nias Y. G. Peng, Luiz Tadeu Moraes Figueiredo, Eduardo Magalhães Rego, Veronica Lippi, Flávio Lauretti, Alberto A. Amarilla, Fernando Q. Cunha, Gabriel Shimizu Bassi, José C. Alves-Filho, Wilson Gómez Manrique, Christie Ramos Andrade Leite-Panissi, and Marcílio Jorge Fumagalli
- Subjects
0301 basic medicine ,ROCV ,CCR2 ,Receptors, CCR2 ,encephalitis ,Central nervous system ,Biology ,CCL2 ,Flavivirus Infections ,Pathogenesis ,Mice ,Major Articles and Brief Reports ,03 medical and health sciences ,0302 clinical medicine ,parasitic diseases ,medicine ,Animals ,Immunology and Allergy ,Parasites ,030212 general & internal medicine ,Mice, Knockout ,Flavivirus ,Macrophages ,pathogenesis ,Brain ,medicine.disease ,biology.organism_classification ,FLAVIVIRUS ,Mice, Inbred C57BL ,030104 developmental biology ,Infectious Diseases ,medicine.anatomical_structure ,Knockout mouse ,Immunology ,Female ,Infiltration (medical) ,Brazil ,Encephalitis - Abstract
Rocio virus (ROCV) is a highly neuropathogenic mosquito-transmitted flavivirus responsible for an unprecedented outbreak of human encephalitis during 1975–1976 in Sao Paulo State, Brazil. Previous studies have shown an increased number of inflammatory macrophages in the central nervous system (CNS) of ROCV-infected mice, implying a role for macrophages in the pathogenesis of ROCV. Here, we show that ROCV infection results in increased expression of CCL2 in the blood and in infiltration of macrophages into the brain. Moreover, we show, using CCR2 knockout mice, that CCR2 expression is essential for macrophage infiltration in the brain during ROCV infection and that the lack of CCR2 results in increased disease severity and mortality. Thus, our findings show the protective role of CCR2-mediated infiltration of macrophages in the brain during ROCV infection., Rocio virus (ROCV) is a highly neuropathogenic mosquito-transmitted flavivirus responsible for an unprecedented outbreak of human encephalitis in Brazil. Here, we show that infiltrated macrophages in the brain may be protective in the pathogenesis of ROCV in a mouse model.
- Published
- 2019
17. Fetal Brain Infection Is Not a Unique Characteristic of Brazilian Zika Viruses
- Author
-
Yin Xiang Setoh, Eri Nakayama, Alexander A. Khromykh, Natalie A. Prow, Nias Y. G. Peng, Andreas Suhrbier, Alberto A. Amarilla, Setoh, Yin Xiang, Peng, Nias Y, Nakayama, Eri, Amarilla, Alberto A, Prow, Natalie A, Suhrbier, Andreas, and Khromykh, Alexander A
- Subjects
0301 basic medicine ,Microcephaly ,congenital Zika syndrome ,Lineage (genetic) ,Placenta ,030231 tropical medicine ,lcsh:QR1-502 ,Receptor, Interferon alpha-beta ,Biology ,Virus Replication ,fetal infection ,Asian lineage ,lcsh:Microbiology ,Zika virus ,03 medical and health sciences ,Mice ,0302 clinical medicine ,Fetus ,Virology ,Chlorocebus aethiops ,medicine ,Animals ,Humans ,Viremia ,Pregnancy Complications, Infectious ,Vero Cells ,Mice, Knockout ,Pregnancy ,Zika Virus Infection ,Communication ,Brain ,medicine.disease ,biology.organism_classification ,Embryonic stem cell ,In vitro ,3. Good health ,Mice, Inbred C57BL ,Disease Models, Animal ,030104 developmental biology ,Infectious Diseases ,Vero cell ,Female ,pregnancy - Abstract
The recent emergence of Zika virus (ZIKV) in Brazil was associated with an increased number of fetal brain infections that resulted in a spectrum of congenital neurological complications known as congenital Zika syndrome (CZS). Herein, we generated de novo from sequence data an early Asian lineage ZIKV isolate (ZIKV-MY; Malaysia, 1966) not associated with microcephaly and compared the in vitro replication kinetics and fetal brain infection in interferon α/β receptor 1 knockout (IFNAR1−/−) dams of this isolate and of a Brazilian isolate (ZIKV-Natal; Natal, 2015) unequivocally associated with microcephaly. The replication efficiencies of ZIKV-MY and ZIKV-Natal in A549 and Vero cells were similar, while ZIKV-MY replicated more efficiently in wild-type (WT) and IFNAR−/− mouse embryonic fibroblasts. Viremias in IFNAR1−/− dams were similar after infection with ZIKV-MY or ZIKV-Natal, and importantly, infection of fetal brains was also not significantly different. Thus, fetal brain infection does not appear to be a unique feature of Brazilian ZIKV isolates.
- Published
- 2018
18. Determinants of Zika virus host tropism uncovered by deep mutational scanning
- Author
-
Yin Xiang, Setoh, Alberto A, Amarilla, Nias Y G, Peng, Rebecca E, Griffiths, Julio, Carrera, Morgan E, Freney, Eri, Nakayama, Shinya, Ogawa, Daniel, Watterson, Naphak, Modhiran, Faith Elizabeth, Nanyonga, Francisco J, Torres, Andrii, Slonchak, Parthiban, Periasamy, Natalie A, Prow, Bing, Tang, Jessica, Harrison, Jody, Hobson-Peters, Thom, Cuddihy, Justin, Cooper-White, Roy A, Hall, Paul R, Young, Jason M, Mackenzie, Ernst, Wolvetang, Jesse D, Bloom, Andreas, Suhrbier, and Alexander A, Khromykh
- Subjects
Models, Molecular ,Zika Virus Infection ,DNA Mutational Analysis ,Mosquito Vectors ,Zika Virus ,Virus Replication ,Biological Evolution ,Host Specificity ,Mice, Inbred C57BL ,Mice ,Viral Tropism ,Viral Envelope Proteins ,Aedes ,Chlorocebus aethiops ,Mutation ,Animals ,Humans ,Female ,Selection, Genetic ,Vero Cells - Abstract
Arboviruses cycle between, and replicate in, both invertebrate and vertebrate hosts, which for Zika virus (ZIKV) involves Aedes mosquitoes and primates
- Published
- 2018
19. Full genome sequence of Rocio virus reveal substantial variations from the prototype Rocio virus SPH 34675 sequence
- Author
-
Parthiban Periasamy, Alexander A. Khromykh, Yin Xiang Setoh, Luiz Tadeu Moraes Figueiredo, Victor Hugo Aquino, Nias Y. G. Peng, Alberto A. Amarilla, and Andrii Slonchak
- Subjects
0301 basic medicine ,Gene Expression Regulation, Viral ,Genome, Viral ,Biology ,Genome ,Arbovirus ,03 medical and health sciences ,Viral Proteins ,0302 clinical medicine ,Virology ,medicine ,030212 general & internal medicine ,Amino Acid Sequence ,Peptide sequence ,Sequence (medicine) ,Whole genome sequencing ,Genetics ,Flavivirus ,RNA ,EXPRESSÃO GÊNICA ,General Medicine ,medicine.disease ,biology.organism_classification ,030104 developmental biology ,GenBank ,Nucleic Acid Conformation ,RNA, Viral - Abstract
Rocio virus (ROCV) is an arbovirus belonging to the genus Flavivirus, family Flaviviridae. We present an updated sequence of ROCV strain SPH 34675 (GenBank: AY632542.4), the only available full genome sequence prior to this study. Using next-generation sequencing of the entire genome, we reveal substantial sequence variation from the prototype sequence, with 30 nucleotide differences amounting to 14 amino acid changes, as well as significant changes to predicted 3’UTR RNA structures. Our results present an updated and corrected sequence of a potential emerging human-virulent flavivirus uniquely indigenous to Brazil (GenBank: MF461639).
- Published
- 2018
20. Helicase Domain of West Nile Virus NS3 Protein Plays a Role in Inhibition of Type I Interferon Signalling
- Author
-
Nias Y. G. Peng, Parthiban Periasamy, Yin Xiang Setoh, Alexander A. Khromykh, Andrii Slonchak, and Alberto A. Amarilla
- Subjects
0301 basic medicine ,NS3 ,medicine.medical_treatment ,viruses ,030106 microbiology ,lcsh:QR1-502 ,Virulence ,Viral Nonstructural Proteins ,Virus Replication ,lcsh:Microbiology ,Virus ,Article ,03 medical and health sciences ,Mice ,flavivirus ,Interferon ,Virology ,medicine ,Animals ,Humans ,Protease ,biology ,Virus Assembly ,DNA Helicases ,Helicase ,virus diseases ,interferon ,biology.organism_classification ,Flavivirus ,helicase ,030104 developmental biology ,Infectious Diseases ,Viral replication ,Interferon Type I ,biology.protein ,West Nile virus ,West Nile Fever ,medicine.drug ,Peptide Hydrolases ,Signal Transduction - Abstract
West Nile virus (WNV) is a neurotropic flavivirus that can cause encephalitis in mammalian and avian hosts. In America, the virulent WNV strain (NY99) is causing yearly outbreaks of encephalitis in humans and horses, while in Australia the less virulent Kunjin strain of WNV strain has not been associated with significant disease outbreaks until a recent 2011 large outbreak in horses (but not in humans) caused by NSW2011 strain. Using chimeric viruses between NY99 and NSW2011 strains we previously identified a role for the non-structural proteins of NY99 strain and especially the NS3 protein, in enhanced virus replication in type I interferon response-competent cells and increased virulence in mice. To further define the role of NY99 NS3 protein in inhibition of type I interferon response, we have generated and characterised additional chimeric viruses containing the protease or the helicase domains of NY99 NS3 on the background of the NSW2011 strain. The results identified the role for the helicase but not the protease domain of NS3 protein in the inhibition of type I interferon signalling and showed that helicase domain of the more virulent NY99 strain performs this function more efficiently than helicase domain of the less virulent NSW2011 strain. Further analysis with individual amino acid mutants identified two amino acid residues in the helicase domain primarily responsible for this difference. Using chimeric replicons, we also showed that the inhibition of type I interferon (IFN) signalling was independent of other known functions of NS3 in RNA replication and assembly of virus particles.
- Published
- 2017
- Full Text
- View/download PDF
21. Chimeric viruses between Rocio and West Nile: the role for Rocio prM-E proteins in virulence and inhibition of interferon-α/β signaling
- Author
-
Gabor Pali, Nias Y. G. Peng, Parthiban Periasamy, Alberto A. Amarilla, Luiz Tadeu Moraes Figueiredo, Alexander A. Khromykh, Victor Hugo Aquino, and Yin Xiang Setoh
- Subjects
0301 basic medicine ,DNA, Complementary ,viruses ,Virulence ,Virus Replication ,Virus ,Article ,03 medical and health sciences ,Viral Proteins ,Interferon ,parasitic diseases ,medicine ,Seroprevalence ,Animals ,Humans ,Cloning, Molecular ,Phosphorylation ,Gene ,Janus Kinases ,Multidisciplinary ,biology ,REPLICAÇÃO VIRAL ,Flaviviridae ,Outbreak ,virus diseases ,Interferon-alpha ,Interferon-beta ,medicine.disease ,biology.organism_classification ,Virology ,3. Good health ,Mice, Inbred C57BL ,Flavivirus ,STAT Transcription Factors ,030104 developmental biology ,HEK293 Cells ,Female ,West Nile virus ,Encephalitis ,medicine.drug ,Signal Transduction - Abstract
Mosquito-transmitted flavivirus Rocio (ROCV) was responsible for an outbreak of encephalitis in the Ribeira Valley, located in the south coast of Sao Paulo State, Brazil, in 1975–1976. ROCV also causes fatal encephalitis in adult mice. Seroprevalence studies in humans, horses and water buffaloes in different regions of Brazil have suggested that ROCV is still circulating in the country, indicating the risk of re-emergence of this virus. West Nile virus (WNV) is also a mosquito-transmitted encephalitic flavivirus, however, WNV strains circulating in Australia have not been associated with outbreaks of disease in humans and exhibit low virulence in adult mice. To identify viral determinants of ROCV virulence, we have generated reciprocal chimeric viruses between ROCV and the Australian strain of WNV by swapping structural prM and E genes. Chimeric WNV containing ROCV prM-E genes replicated more efficiently than WNV or chimeric ROCV containing WNV prM-E genes in mammalian cells, was as virulent as ROCV in adult mice, and inhibited type I IFN signaling as efficiently as ROCV. The results show that ROCV prM and E proteins are major virulence determinants and identify unexpected function of these proteins in inhibition of type I interferon response.
- Published
- 2017
22. [Intervention of systolic pressure and left ventricular hypertrophy in rats under cold stress]
- Author
-
C F, Sun, S G, Wang, Y G, Peng, Y, Shi, Y P, Du, G X, Shi, T, Wen, Y K, Wang, and H, Su
- Subjects
Cold Temperature ,Male ,Endothelin-1 ,Stress, Physiological ,Angiotensin II ,Myocardium ,Rats, Inbred SHR ,Hypertension ,Animals ,Blood Pressure ,Hypertrophy, Left Ventricular ,Benzazepines ,Rats - Abstract
To investigate the effects of different drugs on systolic blood pressure (SBP) and left ventricular hypertrophy (LVH) in spontaneously hypertensive rats under cold stress.A total of 40 male spontaneously hypertensive rats aged 10 weeks (160~200 g) were given adaptive feeding for 7 days at a temperature of 20±1°C and then randomly divided into control group, cold stress group, metoprolol group, amlodipine group, and benazepril group, with 8 rats in each group. SBP, body weight, and heart rate were measured once a week. After the rats were sacrificed by exsanguination, left ventricular weight (LVW) was measured, and left ventricular weight index (LVWI; mg/g) was calculated. Radioimmunoassay was used to measure the concentrations of endothelin-1 (ET-1) and angiotensin-II (Ang-II) in plasma and myocardium, and the chemical method was used to measure the concentrations of nitric oxide (NO) in plasma and myocardium. RT-PCR was used to measure the mRNA expression of endothelin-A receptor.Compared with the cold stress group, all medication groups showed significant reductions in SBP since week 5 (P0.05). The cold stress group showed a significant increase in LVWI compared with the control group (3.38±0.27 mg/g vs 2.89±0.19 mg/g, P0.05). The amlodipine group showed a significant reduction in LVWI compared with the cold stress group (2.98±0.28 mg/g vs 3.38±0.27 mg/g, P0.05). The cold stress group showed a significant reduction in plasma NO concentration compared with the control group (104.9±19.5 μmol/L vs 129.3±17.8 μmol/L, P0.05) ; compared with the cold stress group, all the medication groups showed significant increases in blood NO concentration (P0.05). The cold stress group showed a significant increase in myocardial ET-1 concentration compared with the control group (6.3±1.5 pg/100 mg vs 4.5±1.9 pg/100 mg, P0.05) ; compared with the cold stress group, the amlodipine group showed a significant reduction in myocardial ET-1 concentration (4.4±1.0 pg/100 mg vs 6.3±1.5 pg/100 mg, P0.05). The cold stress group had significantly higher mRNA expression of endothelin-A receptor than the control group (0.86±0.23 vs 0.45±0.16, P0.01) ; compared with the cold stress group, the amlodipine group showed a significant reduction in the mRNA expression of endothelin-A receptor (0.41±0.14 vs 0.86±0.23, P0.01).Amlodipine can reduce the increase in SBP and inhibit LVH in spontaneously hypertensive rats under cold stress.
- Published
- 2016
23. Nanogranular TiN-ZrO₂ intermediate layer induced improvement of isolation and grain size of FePt thin films
- Author
-
K F, Dong, H H, Li, Y G, Peng, G, Ju, G M, Chow, and J S, Chen
- Subjects
Article - Abstract
The effects of TiN-ZrO2 intermediate layer on the microstructures and magnetic properties of FePt films were investigated. The TiN-ZrO2 intermediate layer was granular consisting of grains of solid solution of Ti(Zr)ON segregated by amorphous ZrO2. By doping ZrO2 into TiN intermediate layer, the FePt grains became better isolated from each other and the FePt grain size was reduced. For 20 vol. % ZrO2 doping into TiN, the grain size decreased dramatically from 11. 2 nm to 6. 4 nm, and good perpendicular anisotropy was achieved simultaneously. For the FePt 4nm-SiO2 35 vol. % -C 20 vol. % films grown on top of the TiN-ZrO2 20 vol. % intermediate layer, well isolated FePt (001) granular films with coercivity higher than 18. 1 kOe and an average size as small as 6. 4 nm were achieved.
- Published
- 2014
24. Brain Fos Induction Is a Sensitive Biomarker for the Lowest Observed Neuroexcitatory Effects of Domoic Acid
- Author
-
Y G, Peng and J S, Ramsdell
- Subjects
Kainic Acid ,Behavior, Animal ,Dose-Response Relationship, Drug ,Brain ,Blotting, Northern ,Toxicology ,Hippocampus ,Mice ,Oncogene Proteins v-fos ,Animals ,Female ,Marine Toxins ,RNA, Messenger ,Biomarkers - Abstract
Domoic acid induces Fos in several brain regions controlling memory processing and gastrointestinal functions. In the present study, we determined serum levels of domoic acid that caused observable effects, and examined whether brain c-fos was a sensitive marker for the lowest observed neuroexcitatory effects in mice. Five different doses (0.25 to 4.0 mg/kg) of domoic acid were intraperitoneally administered to mice, and the serum concentration of domoic acid was monitored using a radioreceptor assay. The earliest neuroexcitatory effect of domoic acid on behavior was observed in the form of hyperactivity which occurred at 0.5 mg/kg (0.076 +/- 0.02 microgram/ml serum domoic acid, means +/- SE, n = 5). However, stereotypic behavior (scratching) was observed only at dosesor = 1.0 mg/kg (0.25 +/- 0.02 microgram/ml). At 2.0 mg/kg (0.54 +/- 0.04 microgram/ml) and higher, convulsions and seizures occurred. Domoic acid induction of c-fos mRNA was detected in the whole brain at 1.0 mg/kg, whereas increased Fos immunostaining was localized in the dentate granule cells and the pyramidal cells of hippocampal formation at doses as low as 0.5 mg/kg (0.076 +/- 0.02 microgram/ml). Our results indicate that Fos expression in the hippocampus is a sensitive biomarker for the neuroexcitatory effects of domoic acid, being induced at doses of domoic acid lower than those that elicit stereotypic behavior.
- Published
- 1996
25. Capnography during anesthesia
- Author
-
J. S. Gravenstein, Y. G. Peng, and D. A. Paulus
- Subjects
Pulse oximetry ,Capnography ,medicine.diagnostic_test ,Respiratory rate ,business.industry ,Anesthesia ,Intensive care ,Medicine ,Pain management ,business ,Aortic surgery ,Lung recruitment ,Neurosurgical anesthesia - Published
- 2011
26. [Untitled]
- Author
-
A. D. Li, Julong He, D. C. Li, Linghao Li, T. S. Wang, Yongjun Tian, Dongli Yu, F. R. Xiao, and Y. G. Peng
- Subjects
chemistry.chemical_classification ,Materials science ,Crystal chemistry ,Stereochemistry ,Chemical synthesis ,law.invention ,Boric acid ,chemistry.chemical_compound ,Crystallography ,chemistry ,law ,Boron nitride ,General Materials Science ,Crystallization ,Inorganic compound ,Chemical composition ,Carbon nitride - Published
- 2000
27. Advanced glycation end-products and methionine sulphoxide in skin collagen of patients with type 1 diabetes
- Author
-
J. N. Shaw, John W. Baynes, Alicia J. Jenkins, Mark A. Sochaski, Timothy J. Lyons, Yongxin Yu, Daniel L. McGee, N. Silvers, Y. G. Peng, John A. McKnight, Trevor J. Orchard, Suzanne R. Thorpe, and Christopher E. Aston
- Subjects
Adult ,Glycation End Products, Advanced ,Male ,medicine.medical_specialty ,endocrine system diseases ,Endocrinology, Diabetes and Metabolism ,Biopsy ,Gastroenterology ,chemistry.chemical_compound ,Methionine ,Glycation ,Reference Values ,Diabetes mellitus ,Internal medicine ,Immunopathology ,Epidemiology ,Internal Medicine ,medicine ,Humans ,Triglycerides ,Aged ,Skin ,Glycated Hemoglobin ,Type 1 diabetes ,medicine.diagnostic_test ,Cholesterol ,business.industry ,Cholesterol, HDL ,Cholesterol, LDL ,Middle Aged ,medicine.disease ,Surgery ,Diabetes Mellitus, Type 1 ,chemistry ,Female ,Collagen ,Complication ,business - Abstract
We determined whether oxidative damage in collagen is increased in (1) patients with diabetes; (2) patients with diabetic complications; and (3) subjects from the Diabetes Control and Complications Trial (DCCT)/Epidemiology of Diabetes Interventions and Complications (EDIC) study, with comparison of subjects from the former standard vs intensive treatment groups 4 years after DCCT completion.We quantified the early glycation product fructose-lysine, the two AGEs N (epsilon)-(carboxymethyl)lysine (CML) and pentosidine, and the oxidised amino acid methionine sulphoxide (MetSO) in skin collagen from 96 patients with type 1 diabetes (taken from three groups: DCCT/EDIC patients and clinic patients from South Carolina and Scotland) and from 78 healthy subjects.Fructose-lysine was increased in diabetic patients (p0.0001), both with or without complications (p0.0001). Controlling for HbA(1c), rates of accumulation of AGEs were higher in diabetic patients than control subjects, regardless of whether the former had complications (CML and pentosidine given as log(e)[pentosidine]) or not (CML only) (all p0.0001). MetSO (log(e)[MetSO]) also accumulated more rapidly in diabetic patients with complications than in controls (p0.0001), but rates were similar in patients without complications and controls. For all three products, rates of accumulation with age were significantly higher in diabetic patients with complications than in those without (all p0.0001). At 4 years after the end of the DCCT, no differences were found between the previous DCCT management groups for fructose-lysine, AGEs or MetSO.The findings suggest that in type 1 diabetic patients enhanced oxidative damage to collagen is associated with the presence of vascular complications.
- Published
- 2005
28. L10 FePt-ZrO2 (001) nanostructured films with high aspect ratio columnar grains
- Author
-
Jingsheng Chen, Huihui Li, Gan Moog Chow, K. F. Dong, Y. G. Peng, and Ganping Ju
- Subjects
Magnetic anisotropy ,Tetragonal crystal system ,Materials science ,Nanocomposite ,Physics and Astronomy (miscellaneous) ,Metallurgy ,Sputter deposition ,Thin film ,Composite material ,Coercivity ,Epitaxy ,Grain size - Abstract
In order to increase the signal-to-noise ratio of heat assisted magnetic recording, it is desirable to fabricate high magnetic anisotropy FePt media with small grain size and high aspect ratio (grain height to size ratio). In the present paper, we report that FePt media with small grain size and high aspect ratio were achieved by doping ZrO2 into FePt film grown on TiON intermediate layer. The grain size was around 5.6 nm, and the aspect ratio was as high as 2.6. It is believed that this originated from the ZrO2 (002) tetragonal crystalline phase epitaxially grown on TiON intermediate layer. With a 5 vol. % carbon doping into FePt-ZrO2 films, the perpendicular anisotropy was improved and the out-of-plane coercivity was around 23.2 kOe. Doping of crystalline phase material with certain required crystal structure may offer a method for fabrication of nanostructured thin films with high aspect ratio grains at high processing temperature.
- Published
- 2014
29. Domoic acid is a potent neurotoxin to neonatal rats
- Author
-
D, Xi, Y G, Peng, and J S, Ramsdell
- Subjects
Lethal Dose 50 ,Kainic Acid ,Animals, Newborn ,Behavior, Animal ,Dose-Response Relationship, Drug ,Neurotoxins ,Animals ,Rats, Inbred Strains ,Nervous System Diseases ,Rats - Abstract
Domoic acid induces a time-dependent neuroexcitotoxic effect in neonatal rats characterized by hyperactivity, stereotypic scratching, convulsions, and death with observable behaviors occurring at exposures 40 times lower by body weight in neonates than reported in adults. Low doses of domoic acid (0.1 mg/kg) induced c-fos in the central nervous system which was inhibited in part by 2-amino-5-phosphonovaleric acid, an NMDA receptor antagonist. Domoic acid caused no evidence of structural alteration in the brain of neonates as assessed by Nissel staining and cupric silver histochemistry. Domoic acid induced reproducible behavioral effects at doses as low as 0.05 mg/kg and induced seizures doses as low as 0.2 mg/kg. Determination of serum domoic acid levels after 60 min exposure indicated that serum levels of domoic acid in the neonates corresponded closely to the serum levels that induce similar symptoms in adult rats and mice. We conclude that neonatal rats are highly sensitive to the neuroexcitatory and lethal effects of domoic acid and that the increased sensitivity results from higher than expected serum levels of domoic acid. These findings are consistent with other findings that reduced serum clearance of domoic acid is a predisposing factor to domoic acid toxicity.
- Published
- 1997
30. Asymmetric α-Alkylation of Ketones by Brønsted Acid Catalysis
- Author
-
J Tian, Q.-X. Guo, Y.-G. Peng, X.-C Li, and L. Song
- Subjects
Chemistry ,Organic chemistry ,Alkylation ,Brønsted–Lowry acid–base theory ,Catalysis - Published
- 2012
31. Bulk anisotropic composite rare earth magnets
- Author
-
M. Q. Huang, S. Liu, Christina H. Chen, A. Higgins, David E. Laughlin, S. Bauser, Don Lee, and Y. G. Peng
- Subjects
business.product_category ,Materials science ,Metallurgy ,Composite number ,General Physics and Astronomy ,Deformation (meteorology) ,Microstructure ,Ferromagnetism ,Phase (matter) ,Magnet ,Die (manufacturing) ,Coupling (piping) ,Composite material ,business - Abstract
Bulk anisotropic composite Nd13.5Fe80Ga0.5B6∕α-Fe and Nd14Fe79.5Ga0.5B6∕Fe–Co magnets with (BH)max=45–50MGOe have been synthesized by blending a Nd–Fe–Ga–B powder with an α-Fe or Fe–Co powder followed by hot compaction at 600–700 °C and hot deformation (die upsetting) at 850–950 °C with a height reduction of 71%. The composite Nd13.5Fe80Ga0.5B6∕α-Fe and Nd14Fe79.5Ga0.5B6∕Fe–Co magnets show microstructures consisting of a very large soft phase up to ∼50μm, which is more than 1000 times larger than the upper size limit of the soft phase expected from the existing models of interface exchange coupling.
- Published
- 2006
32. Fully dense anisotropic nanocomposite Sm(Co,Fe,Zr,Cu,B)z (z=7.5–12) magnets
- Author
-
B. M. Ma, Richard T. Fingers, S. Liu, David E. Laughlin, M. Q. Huang, D. Lee, B. Wheeler, S. Y. Chu, John Horwath, Y. G. Peng, and Zafer Turgut
- Subjects
Magnetization ,Magnetic anisotropy ,Nanocomposite ,Materials science ,Condensed matter physics ,Transmission electron microscopy ,Magnet ,Metallurgy ,X-ray crystallography ,General Physics and Astronomy ,Hot pressing ,Magnetic hysteresis - Abstract
Fully dense anisotropic nanocomposite Sm(Co0.58Fe0.31Zr0.05Cu0.04B0.02)z (z=7.5–12) magnets have been synthesized via rapid hot pressing and hot deformation processes. The highest (BH)max∼10.6MGOe was observed for a magnet with z=10. X-ray diffraction and M-H measurements indicated that the easy magnetization direction of magnets prefers to be in the hot pressing direction. Transmission electron microscopy investigation confirmed that plastic deformation is an important route for forming magnetic anisotropy in the Sm–Co-type nanocomposite magnets. Some stripe and/or platelike patterns have been observed inside the nanograins (50–200nm), which may present as twins, and stacking faults. The (0001) twins have been observed in the 2:17R phase.
- Published
- 2005
33. [The treatment of cervix erosion using electrical pressing and cauterization: 411 case reports]
- Author
-
Y G, Peng
- Subjects
Adult ,Electrocoagulation ,Humans ,Female ,Uterine Cervical Erosion - Published
- 1984
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.