27 results on '"Kemin Xu"'
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2. Antigenic Variation of Clade 2.1 H5N1 Virus Is Determined by a Few Amino Acid Substitutions Immediately Adjacent to the Receptor Binding Site
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Björn F. Koel, Stefan van der Vliet, David F. Burke, Theo M. Bestebroer, Eny E. Bharoto, I. Wayan W. Yasa, Inna Herliana, Brigitta M. Laksono, Kemin Xu, Eugene Skepner, Colin A. Russell, Guus F. Rimmelzwaan, Daniel R. Perez, Albert D. M. E. Osterhaus, Derek J. Smith, Teguh Y. Prajitno, and Ron A. M. Fouchier
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Microbiology ,QR1-502 - Abstract
ABSTRACT Highly pathogenic avian influenza (HPAI) viruses of the H5N1 subtype are genetically highly variable and have diversified into multiple phylogenetic clades over the past decade. Antigenic drift is a well-studied phenomenon for seasonal human influenza viruses, but much less is known about the antigenic evolution of HPAI H5N1 viruses that circulate in poultry. In this study, we focused on HPAI H5N1 viruses that are enzootic to Indonesia. We selected representative viruses from genetically distinct lineages that are currently circulating and determined their antigenic properties by hemagglutination inhibition assays. At least six antigenic variants have circulated between 2003, when H5N1 clade 2.1 viruses were first detected in Indonesia, and 2011. During this period, multiple antigenic variants cocirculated in the same geographic regions. Mutant viruses were constructed by site-directed mutagenesis to represent each of the circulating antigenic variants, revealing that antigenic differences between clade 2.1 viruses were due to only one or very few amino acid substitutions immediately adjacent to the receptor binding site. Antigenic variants of H5N1 virus evaded recognition by both ferret and chicken antibodies. The molecular basis for antigenic change in clade 2.1 viruses closely resembled that of seasonal human influenza viruses, indicating that the hemagglutinin of influenza viruses from different hosts and subtypes may be similarly restricted to evade antibody recognition. IMPORTANCE Highly pathogenic avian influenza (HPAI) H5N1 viruses are responsible for severe outbreaks in both commercial and backyard poultry, causing considerable economic losses and regular zoonotic transmissions to humans. Vaccination is used increasingly to reduce the burden of HPAI H5N1 virus in poultry. Influenza viruses can escape from recognition by antibodies induced upon vaccination or infection through genetic changes in the hemagglutinin protein. The evolutionary patterns and molecular basis of antigenic change in HPAI H5N1 viruses are poorly understood, hampering formulation of optimal vaccination strategies. We have shown here that HPAI H5N1 viruses in Indonesia diversified into multiple antigenic variants, that antigenic differences were due to one or a very few substitutions near the receptor binding site, and that the molecular basis for antigenic change was remarkably similar to that for seasonal human influenza viruses. These findings have consequences for future vaccination and surveillance considerations and contribute to the understanding of the antigenic evolution of influenza viruses.
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- 2014
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3. Partial and full PCR-based reverse genetics strategy for influenza viruses.
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Hongjun Chen, Jianqiang Ye, Kemin Xu, Matthew Angel, Hongxia Shao, Andrea Ferrero, Troy Sutton, and Daniel R Perez
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Medicine ,Science - Abstract
Since 1999, plasmid-based reverse genetics (RG) systems have revolutionized the way influenza viruses are studied. However, it is not unusual to encounter cloning difficulties for one or more influenza genes while attempting to recover virus de novo. To overcome some of these shortcomings we sought to develop partial or full plasmid-free RG systems. The influenza gene of choice is assembled into a RG competent unit by virtue of overlapping PCR reactions containing a cDNA copy of the viral gene segment under the control of RNA polymerase I promoter (pol1) and termination (t1) signals - herein referred to as Flu PCR amplicons. Transfection of tissue culture cells with either HA or NA Flu PCR amplicons and 7 plasmids encoding the remaining influenza RG units, resulted in efficient virus rescue. Likewise, transfections including both HA and NA Flu PCR amplicons and 6 RG plasmids also resulted in efficient virus rescue. In addition, influenza viruses were recovered from a full set of Flu PCR amplicons without the use of plasmids.
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- 2012
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4. Variations in the hemagglutinin of the 2009 H1N1 pandemic virus: potential for strains with altered virulence phenotype?
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Jianqiang Ye, Erin M Sorrell, Yibin Cai, Hongxia Shao, Kemin Xu, Lindomar Pena, Danielle Hickman, Haichen Song, Matthew Angel, Rafael A Medina, Balaji Manicassamy, Adolfo Garcia-Sastre, and Daniel R Perez
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Immunologic diseases. Allergy ,RC581-607 ,Biology (General) ,QH301-705.5 - Abstract
A novel, swine-origin influenza H1N1 virus (H1N1pdm) caused the first pandemic of the 21st century. This pandemic, although efficient in transmission, is mild in virulence. This atypical mild pandemic season has raised concerns regarding the potential of this virus to acquire additional virulence markers either through further adaptation or possibly by immune pressure in the human host. Using the mouse model we generated, within a single round of infection with A/California/04/09/H1N1 (Ca/04), a virus lethal in mice--herein referred to as mouse-adapted Ca/04 (ma-Ca/04). Five amino acid substitutions were found in the genome of ma-Ca/04: 3 in HA (D131E, S186P and A198E), 1 in PA (E298K) and 1 in NP (D101G). Reverse genetics analyses of these mutations indicate that all five mutations from ma-Ca/04 contributed to the lethal phenotype; however, the D131E and S186P mutations--which are also found in the 1918 and seasonal H1N1 viruses-in HA alone were sufficient to confer virulence of Ca/04 in mice. HI assays against H1N1pdm demonstrate that the D131E and S186P mutations caused minor antigenic changes and, likely, affected receptor binding. The rapid selection of ma-Ca/04 in mice suggests that a virus containing this constellation of amino acids might have already been present in Ca/04, likely as minor quasispecies.
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- 2010
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5. Clonal relationship of extranodal marginal zone lymphomas of mucosa-associated lymphoid tissue (MALT lymphoma) involving multiple organ systems with review of the literature
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Kemin Xu and Nicholas Ward
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Histology ,Hematology ,Pathology and Forensic Medicine - Published
- 2022
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6. Recognizing deformation origins: a review of deformation structures and hypothesis on the perspective of sediment consolidation
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Mingming Cui, Nan Peng, Yongqing Liu, Zongxiu Wang, Chunlin Li, Kemin Xu, and Hongwei Kuang
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Geology - Published
- 2022
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7. Field Excursion Introduction for IGCP 679 1st International Symposium: Progress in Cretaceous Geology in Shandong Province, China
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Xueqiang Zhu, Jie Qin, Zhenguo Ning, Fuzhong Zhang, Youping Wang, Gang Li, Xiuzhang Li, and Kemin Xu
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Paleontology ,Group (stratigraphy) ,Excursion ,Radiometric dating ,Structural basin ,Chronostratigraphy ,Paleogene ,Cretaceous ,Geology ,Zircon - Abstract
The non-marine Cretaceous sequences are well developed in the relict basins, i.e. the Luxi basin in the west, and the Jiaolai basin in the east of Shandong Province. The Lower Cretaceous Santai Formation (140 - 136 Ma) in the Luxi basin contains aeolian dune deposits, which were formed under the control by westerly. The Cretaceous strata of the Jiaolai basin are divided into three groups: i.e. in ascending order, the Laiyang, Qingshan and Wangshi groups. New SHRIMP zircon U-Pb radiometric dating data demonstrated six Cretaceous volcanism episodes. The lower part of the Wangshi Group should be assigned to the upper Lower Cretaceous. An Ir anomaly recovered in the lower Jiaozhou Formation suggests that the Cretaceous/Palaeogene boundary would be in the interval between 537.3 - 537.4 m in the borehole JK1. At last the detailed information about the pre-symposium field excursion was introduced.
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- 2019
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8. Cretaceous Stratigraphy, Paleoenvironment and Terrestrial Biota in Shandong Province
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Nan Peng, Kemin Xu, Yongqing Liu, Zhenguo Ning, and Hongwei Kuang
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Paleontology ,Stratigraphy ,Group (stratigraphy) ,Fauna ,Period (geology) ,Paleoecology ,Ecological succession ,Terrestrial biota ,Geology ,Cretaceous - Abstract
The terrestrial upper Jurassic-Cretaceous (upper and lower)-Cenozoic stratigraphic succession developed continuously in Shandong province. There are intact and continuous terrestrial paleoecosystems dominated by dinosaurs, including five vertebrate fauna (bone fossil assemblages) beds from the bottom to top in the Cretaceous successions of Shandong Province. There are multiple vertebrate footprints (group) bearing beds in the transition period between Jurassic-Cretaceous and Early Cretaceous, and multiple large-scale dinosaur burial bone beds in Late Cretaceous. In recent years, it has also been found that extraterrestrial impact geological event may occur in the K/Pg transition over a hundred meters (siliceous pellet and gamma element anomalies, etc.). Shandong has a well-developed terrestrial Cretaceous succession with perfect information on paleoenvironment and paleoecology, which is an ideal area to explore the co-evolutionary relationship between terrestrial biota and paleoenvironment.
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- 2019
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9. Preface Cretaceous Earth Dynamics and Climate in Asia
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Zhigang Zhang, Gang Li, Xin Li, Petr Schnabl, Zhenguo Ning, Kemin Xu, Jie Qin, Jing Guo, and Yongbo Huang
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Earth science ,Earth (chemistry) ,Geology ,Cretaceous - Published
- 2019
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10. A Comparative Analysis of Immunohistochemical Profile of Primary and Metastatic Endometrial Endometrioid Carcinoma
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Minghao Zhong, L Han, Kemin Xu, and Qiqi Ye
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Pathology ,medicine.medical_specialty ,Primary (chemistry) ,business.industry ,Carcinoma ,Medicine ,Immunohistochemistry ,General Medicine ,business ,medicine.disease - Abstract
Introduction/Objective Beta catenin plays an important role in cancer tumorigenesis and have been found to be associated with metastasis in a variety of tumors. Analyzing TCGA data, we found that 30% of endometrial endometrioid carcinoma cases have beta-catenin mutations. We hypothesize that beta-catenin mutation may be associated with metastasis of endometrial endometrioid carcinoma. ER and PR expression was also compared to determine any changes after metastasis. Methods Retrospective institutional review of all endometrial endometrioid carcinoma (192 cases) between 2011 to 2018 was performed, including 149 cases of FIGO grade I, 38 cases of FIGO grade II and 5 cases of FIGO grade III. 19 cases with paired primary and metastatic specimen were identified. Immunohistochemistry staining (IHC) was carried out for ER, PR and beta-catenin. Results Median patient age was 56 years. The most common metastatic site was vagina, accounting for 68% of metastasis (14/19), followed by bladder (3/19), lung (2/19) and rectum (1/19). The primary and metastatic carcinoma of all 19 cases exhibit very similar morphology. All of those cases were positive and concordant for ER and PR in primary and metastatic endometrioid carcinoma. On the other hand, nuclear beta-catenin staining caused by mutation was positive in 5 metastatic carcinoma but not in primary carcinoma. Conclusion IHC expression of ER and PR remains unchanged between primary and metastatic carcinoma, demonstrating the reliability of ER and PR to confirm the origin of metastatic carcinoma. 26% of the metastatic carcinoma (5/19) exhibit nuclear beta-catenin staining but not in primary carcinoma, suggesting the possible role of beta-catenin in metastasis of endometrial endometrioid carcinoma.
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- 2020
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11. Diverse preserved dinosaur footprint assemblage from Jurassic–Cretaceous transition eolian dune deposits of western Shandong Province, China
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Hong-Wei Kuang, Nan Peng, Jun Chen, Yong-Qing Liu, Huan Xu, and Kemin Xu
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010506 paleontology ,biology ,Fauna ,Paleontology ,Trace fossil ,010502 geochemistry & geophysics ,biology.organism_classification ,01 natural sciences ,Arid ,Cretaceous ,Aeolian processes ,Ichnofacies ,Mesozoic ,Geology ,0105 earth and related environmental sciences ,Ornithopod - Abstract
Ancient desert, characterized by low biotic diversity as well as low preservation potential, has long been assumed as devoid of biotic activity. However, recent works from Mesozoic trace fossils preserved in the eolianites in North America, South America and East Asia indicate that the ancient desert can also have diverse inhabitants. This paper presents a diversified preserved dinosaur track assemblage from the Jurassic-Cretaceous transition eolian dune deposits in western Shandong Province, China. Based on the ichnological analysis, tracks are assigned to ichnogenus Anomoepus, Eubrontes-like and Ornithopodichnus-like forms, representing the oldest and second example of the Chelichnus ichnofacies reported from China as well as Asia. Sedimentological analysis of the tracksites indicates that tracks occurred in linear dunes under arid climatic conditions. Well-preserved tracks with detailed anatomical information are more likely to be preserved in moist sands, contrary to the dry cohesionless sands. Anomoepus and Ornithopodichnus-like tracks cooccurring with northwestward winds were made during summer wet season, while Eubrontes-like track was present during winter dry season characterized by strong northeastward wind, implying different habits between ornithopod and theropod dinosaurs. The preserved Jurassic-Cretaceous transition dinosaur tracks in eolian dune deposits not only expand the spatial-temporal distribution of dinosaur fauna in North China, but also greatly improve our understanding of the adaptive capacity of dinosaurs in severe living conditions, such as the desert environment.
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- 2021
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12. Detrital zircon dating and tracing the provenance of dinosaur bone beds from the Late Cretaceous Wangshi Group in Zhucheng, Shandong, East China
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Kebai Wang, Shu-Qing Chen, Kemin Xu, Yongqing Liu, Wei An, Huan Xu, Peng Zhang, Yan-Xia Zhang, Nan Peng, and Hongwei Kuang
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010506 paleontology ,Provenance ,Wangshi Group ,Geography, Planning and Development ,Geochronology ,Pyroclastic rock ,Detrital zircon ,010502 geochemistry & geophysics ,01 natural sciences ,Conglomerate ,Sedimentary depositional environment ,Paleontology ,0105 earth and related environmental sciences ,Earth-Surface Processes ,geography ,geography.geographical_feature_category ,Shandong Zhucheng ,Dinosaur bone beds ,QE701-760 ,Cretaceous ,Volcanic rock ,Geology ,Zircon - Abstract
The mass burial of dinosaur bone fossils in the Late Cretaceous Wangshi Group in Zhucheng, Shandong Province has been a research focus in recent years. However, the provenance of the dinosaur bone fossils and the accurate depositional age of the bone beds remain ambiguous. Through U–Pb dating of detrital zircons collected from six conglomerate samples from the dinosaur bone beds, we found that the youngest single grain age (YSG) of sample 090414-24-D was 77.3 Ma, representing the maximum depositional age of the dinosaur fossil beds and sediments. This also indicates that the Hongtuya Formation was deposited during the Campanian. Dating results revealed an age peak of 120–110 Ma, which corresponds with the peak age of volcanic rocks of the Lower Cretaceous Qingshan Group. The volcanic rocks of the Qingshan Group are mainly exposed in Laiyang, to the north of Zhucheng, although a few also appear to the south and northwest. Through analysis of conglomerate composition and palaeocurrents in the sediments containing the bone beds, we found that the three different data sets of gravel compositions of the conglomerates were mainly composed of volcanic or pyroclastic rocks. Three different data sets of palaeocurrents suggested that the main sediment source of the Wangshi Group dinosaur bone beds was from the north−northwest of the Basin. Only one data set had a provenance south of the basin. This study revealed that the areas of Laiyang and the Yishu Fault Zone were the main provenance areas of both the dinosaur bone fossils and the sediments of the Wangshi Group in Zhucheng. The southern margin of the Zhucheng Basin may be a secondary source area. This research provides an important basis for judging the deposition time and the sediment source of fossil layers in the Wangshi Group, as well as reconstructing the palaeogeography of the Wangshi Group in the Jiaolai Basin.
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- 2016
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13. Proximal Type - Epithelioid Sarcoma- A Rare And Aggressive Soft Tissue Neoplasm
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Fouzia Shakil, Kemin Xu, and S Zaheer
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Pathology ,medicine.medical_specialty ,Soft Tissue Neoplasm ,medicine.diagnostic_test ,business.industry ,General Medicine ,medicine.disease ,HMB-45 ,Proximal-Type Epithelioid Sarcoma ,Biopsy ,Carcinoma ,Medicine ,Immunohistochemistry ,Sarcoma ,business ,Epithelioid cell - Abstract
Introduction/Objective Epithelioid Sarcoma is a rare malignant soft tissue neoplasm that is well known for local recurrence, regional lymph node involvement, and metastasis. It accounts for less than one percent of all sarcomas. Two subtypes of epithelioid sarcoma are described: the conventional or classic subtype and the proximal subtype, with the classic type being more common than the proximal type. We present a case of proximal epithelioid sarcoma involving the inguinal region, in which the patient presented with the history of weight loss for one year and a slow- growing inguinal mass for the last few months. The biopsy was done in an outside hospital and showed carcinoma of unknown origin. Imaging also failed to reveal any clear source of this mass. Methods The mass was resected and sent to pathology, where H&E staining and immunohistochemistry was done for diagnosis. Results The H&E sections of the left inguinal mass showed proliferation of large epithelioid cells with a moderate amount of cytoplasm, vesicular nuclear chromatin and prominent nucleoli. Mitosis was also seen. Necrosis was not identified. Immunohistochemical staining was done and revealed that the tumor cells were immunoreactive for epithelial marker cytokeratin AE1/AE3 and showed loss of INI-1. Tumor cells were also negative for Myogenin, ERG, HMB-45, MART-1, Myo-D1, S100, and SMA. Considering the cytomorphology and immunophenotypic findings the diagnosis of epithelioid sarcoma, proximal type was made. Conclusion Epithelioid sarcoma is a malignant mesenchymal neoplasm with epithelioid cytomorphology and phenotype. Among the two types of epithelioid sarcoma, the proximal type is reported about 50% less than the classic type and is associated with aggressive behavior and worse prognosis. The classic cytomorphology and immunohistochemistry findings helped us in making the diagnosis in this case.
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- 2020
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14. Detecting FLI1 Fusion by Immunohistochemistry (IHC) Stain in Prostatic Adenocarcinoma
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Rugved Pattarkine, Alexandra Budhai, Kemin Xu, and Minghao Zhong
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Pathology ,medicine.medical_specialty ,Tissue microarray ,business.industry ,fungi ,General Medicine ,medicine.disease ,Stain ,Prostate cancer ,medicine.anatomical_structure ,Prostate ,FLI1 ,medicine ,Adenocarcinoma ,Immunohistochemistry ,business ,Transcription factor - Abstract
Objectives The most common genetic alterations in prostate cancer are fusions of ERG and other members of the E26 transformation-specific (ETS) family of transcription factors, including ETV1, ETV4, and FLI1. Analyzing TCGA data, we found that similar to ERG fusion, FLI1 fusion-associated FLI1 mRNA level increases. ERG IHC stain has been a surrogate test for ERG fusion. Therefore, we hypothesize that FLI IHC stain could also be used to detect FLI1 fusion in prostate cancer. Methods In total, 111 primary prostate adenocarcinoma (>10% by volume) cases from our institute were selected for tissue microarray (TMA) construction. The regular full section slides and TMA slides were subject to IHC stain of ERG and FLI1 (Santa Cruz, SC-113). The criteria for positive FLI1 are (1) nuclear staining; (2) only in tumor cells, not in nontumor cells; and (3) FLI1-positive cells should be negative for ERG IHC staining. Results For prostate TMA slides, ~50% of cases were positive for ERG; ~30% of cases were weakly positive for FLI1. However, all of the FLI1 weakly positive cases were positive for ERG as well possibly due to cross-reactivity between ERG and FLI1, which was demonstrated in other studies. Conclusion Overall, we conclude that the cross-reactivity between FL1 and ERG precluded the detection of FLI1 fusion in prostatic adenocarcinoma under current conditions. We are in the process of selecting some cases to detect FLI1 fusion by next-generation sequencing (NGS) and FISH.
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- 2019
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15. Impact of Add-On Laboratory Tests on the Clinical Laboratory
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Patricia Adem, Dana Razzano, Ani Baghian, and Kemin Xu
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chemistry ,business.industry ,Computerized physician order entry ,Creatine kinase MB isoenzyme ,Phosphorus ,Troponin I ,Medicine ,chemistry.chemical_element ,Cardiac enzymes ,General Medicine ,Pharmacology ,business ,Order set - Published
- 2018
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16. Blood Culture Contamination in the Clinical Microbiology Laboratory of a Teaching Hospital
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Hank Wang, John T. Fallon, Sarwat Gilani, and Kemin Xu
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Bacillus (shape) ,biology ,medicine.diagnostic_test ,business.industry ,Propionibacterium ,Corynebacterium ,Micrococcus ,General Medicine ,Contamination ,biology.organism_classification ,Teaching hospital ,Microbiology ,Staphylococcus epidermidis ,Medicine ,Blood culture ,business - Abstract
Objectives Blood culture is one of the most important tests performed in clinical microbiology laboratories. However, blood culture contamination remains a problematic cause of diagnostic errors for laboratory diagnosis and patient management. This aim of this study was to determine blood culture contamination rates and tendency at Westchester Medical Center (WMC), a tertiary teaching hospital in suburban New York City. Methods All blood culture tests at WMC received from January 2017 to December 2018, as well as some historical data from 2007 to 2014, were retrospectively retrieved. Blood culture contamination rates were determined according to the laboratory’s predefined criteria. Results From 2007 to 2014, a total of 209,750 blood cultures were performed with an average contamination rate of 1.6% (ranging from 0.4% to 3.5% monthly). The total numbers of blood cultures performed in 2017 and 2018 were 27,863 and 28,047, respectively. The overall positive rate of blood culture was 6.8% in 2017 and 7.6% in 2018. The contamination rate of blood culture was 0.6% in 2017 and 0.9% in 2018 with very few variations among different months of the year, which was significantly lower than that of the national benchmark (~2.5%) on blood culture contamination. The majority of contaminants were Staphylococcus epidermidis, accounting for 87% of source contamination, followed by Corynebacterium species (5.5%), Bacillus species and Micrococcus species (3.5% each), and Propionibacterium species (0.5%). Conclusion Adherence to current guideline on appropriate blood collection techniques and monthly monitoring and timely feedback to phlebotomists should be continued to keep a low contamination rate for blood culture, which is not only from the perspective of individual patient care but also from the standpoint of hospital epidemiology and public health.
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- 2019
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17. Molecular Basis for Broad Neuraminidase Immunity: Conserved Epitopes in Seasonal and Pandemic H1N1 as Well as H5N1 Influenza Viruses
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Jeffery K. Taubenberger, Ishrat Sultana, Judy D. Easterbrook, Mohsen Rajabi, Kemin Xu, Xiufan Liu, Hongjun Chen, Daniel R. Perez, Laura Couzens, Xiu-Feng Wan, Lei Zhong, Katie H. Rivers, Maryna C. Eichelberger, Hongquan Wan, Jin Gao, Kevin Yang, and Jianqiang Ye
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Cross Protection ,viruses ,Immunology ,Neuraminidase ,Cross Reactions ,Antibodies, Viral ,medicine.disease_cause ,Microbiology ,Epitope ,Virus ,Antigenic drift ,Conserved sequence ,Mice ,Influenza A Virus, H1N1 Subtype ,Orthomyxoviridae Infections ,Virology ,medicine ,Influenza A virus ,Animals ,Conserved Sequence ,Mice, Inbred BALB C ,Influenza A Virus, H5N1 Subtype ,biology ,Immunization, Passive ,Antibodies, Monoclonal ,virus diseases ,Survival Analysis ,Influenza A virus subtype H5N1 ,Epitope mapping ,Insect Science ,biology.protein ,Pathogenesis and Immunity ,Epitopes, B-Lymphocyte ,Epitope Mapping - Abstract
Influenza A viruses, including H1N1 and H5N1 subtypes, pose a serious threat to public health. Neuraminidase (NA)-related immunity contributes to protection against influenza virus infection. Antibodies to the N1 subtype provide protection against homologous and heterologous H1N1 as well as H5N1 virus challenge. Since neither the strain-specific nor conserved epitopes of N1 have been identified, we generated a panel of mouse monoclonal antibodies (MAbs) that exhibit different reactivity spectra with H1N1 and H5N1 viruses and used these MAbs to map N1 antigenic domains. We identified 12 amino acids essential for MAb binding to the NA of a recent seasonal H1N1 virus, A/Brisbane/59/2007. Of these, residues 248, 249, 250, 341, and 343 are recognized by strain-specific group A MAbs, while residues 273, 338, and 339 are within conserved epitope(s), which allows cross-reactive group B MAbs to bind the NAs of seasonal H1N1 and the 1918 and 2009 pandemic (09pdm) H1N1 as well as H5N1 viruses. A single dose of group B MAbs administered prophylactically fully protected mice against lethal challenge with seasonal and 09pdm H1N1 viruses and resulted in significant protection against the highly pathogenic wild-type H5N1 virus. Another three N1 residues (at positions 396, 397, and 456) are essential for binding of cross-reactive group E MAbs, which differ from group B MAbs in that they do not bind 09pdm H1N1 viruses. The identification of conserved N1 epitopes reveals the molecular basis for NA-mediated immunity between H1N1 and H5N1 viruses and demonstrates the potential for developing broadly protective NA-specific antibody treatments for influenza.
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- 2013
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18. MicroRNA-based strategy to mitigate the risk of gain-of-function influenza studies
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Kemin Xu, Courtney Finch, Jillian S. Shapiro, Ryan A. Langlois, Matthew Angel, Benjamin R. tenOever, Randy A. Albrecht, Troy C. Sutton, Ana S. Gonzalez-Reiche, Brian Kimble, Daniel R. Perez, Adolfo García-Sastre, and Mark A. Chua
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Biomedical Research ,viruses ,Biomedical Engineering ,Bioengineering ,Biology ,medicine.disease_cause ,Virus Replication ,Applied Microbiology and Biotechnology ,Article ,Mice ,Orthomyxoviridae Infections ,RNA interference ,Virology ,Influenza A virus ,medicine ,Animals ,Humans ,Tropism ,Risk Management ,Influenza A Virus, H5N1 Subtype ,Transmission (medicine) ,Body Weight ,Ferrets ,virus diseases ,Biocontainment ,Survival Analysis ,Influenza A virus subtype H5N1 ,MicroRNAs ,Viral Tropism ,Viral replication ,Immunology ,Tissue tropism ,Molecular Medicine ,Biotechnology - Abstract
Recent gain-of-function studies in influenza A virus H5N1 strains revealed that as few as three amino-acid changes in the hemagglutinin protein confer the capacity for viral transmission between ferrets1, 2. As transmission between ferrets is considered a surrogate indicator of transmissibility between humans, these studies raised concerns about the risks of gain-of-function influenza A virus research. Here we present an approach to strengthen the biosafety of gain-of-function influenza experiments. We exploit species-specific endogenous small RNAs to restrict influenza A virus tropism. In particular, we found that the microRNA miR-192 was expressed in primary human respiratory tract epithelial cells as well as mouse lungs but absent from the ferret respiratory tract. Incorporation of miR-192 target sites into influenza A virus did not prevent influenza replication and transmissibility in ferrets, but did attenuate influenza pathogenicity in mice. This molecular biocontainment approach should be applicable beyond influenza A virus to minimize the risk of experiments involving other pathogenic viruses.
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- 2013
19. Phylogenetic Analysis of H6 Influenza Viruses Isolated from Rosy-Billed Pochards (Netta peposaca) in Argentina Reveals the Presence of Different HA Gene Clusters
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Hebe Ferreyra, Maria Virginia Rago, Troy C. Sutton, Hongxia Shao, Daniel R. Perez, Ariel Pereda, Marcelo Romano, Agustina Rimondi, María Isabel Craig, Marcela Uhart, Andrea Ferrero, and Kemin Xu
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Genotype ,viruses ,Molecular Sequence Data ,Immunology ,Argentina ,Neuraminidase ,Hemagglutinin (influenza) ,Hemagglutinin Glycoproteins, Influenza Virus ,medicine.disease_cause ,Microbiology ,H5N1 genetic structure ,Evolution, Molecular ,Viral Proteins ,Phylogenetics ,Anseriformes ,Virology ,Evolution of influenza ,Influenza A virus ,medicine ,Animals ,Cluster Analysis ,Clade ,Phylogeny ,biology ,Sequence Analysis, DNA ,Influenza A virus subtype H5N1 ,Genetic Diversity and Evolution ,Insect Science ,biology.protein ,RNA, Viral - Abstract
Until recently, influenza A viruses from wild waterfowl in South America were rarely isolated and/or characterized. To explore the ecology of influenza A viruses in this region, a long-term surveillance program was established in 2006 for resident and migratory water birds in Argentina. We report the characterization of 5 avian influenza viruses of the H6 hemagglutinin (HA) subtype isolated from rosy-billed pochards ( Netta peposaca ). Three of these viruses were paired to an N2 NA subtype, while the other two were of the N8 subtype. Genetic and phylogenetic analyses of the internal gene segments revealed a close relationship with influenza viruses from South America, forming a unique clade and supporting the notion of independent evolution from influenza A viruses in other latitudes. The presence of NS alleles A and B was also identified. The HA and NA genes formed unique clades separate from North American and Eurasian viruses, with the exception of the HA gene of one isolate, which was more closely related to the North American lineage, suggesting possible interactions between viruses of North American and South American lineages. Animal studies suggested that these Argentine H6 viruses could replicate and transmit inefficiently in chickens, indicating limited adaptation to poultry. Our results highlight the importance of continued influenza virus surveillance in wild birds of South America, especially considering the unique evolution of these viruses.
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- 2011
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20. Antigenic variation of clade 2.1 H5N1 virus is determined by a few amino acid substitutions immediately adjacent to the receptor binding site
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I. Wayan W. Yasa, Guus F. Rimmelzwaan, Brigitta M. Laksono, Ron A. M. Fouchier, Daniel R. Perez, Theo M. Bestebroer, Stefan van der Vliet, Teguh Y. Prajitno, Derek J. Smith, David F. Burke, Eugene Skepner, Eny E. Bharoto, Colin A. Russell, Inna Herliana, Björn F. Koel, Albert D. M. E. Osterhaus, Kemin Xu, Burke, David [0000-0001-8830-3951], Russell, Colin [0000-0002-2113-162X], Smith, Derek [0000-0002-2393-1890], Apollo - University of Cambridge Repository, and Virology
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animal diseases ,viruses ,Molecular Sequence Data ,Hemagglutinin (influenza) ,Hemagglutinin Glycoproteins, Influenza Virus ,Biology ,medicine.disease_cause ,Microbiology ,H5N1 genetic structure ,Antigenic drift ,SDG 3 - Good Health and Well-being ,Virology ,Influenza, Human ,Antigenic variation ,medicine ,Animals ,Humans ,Amino Acid Sequence ,Clade ,Phylogeny ,Poultry Diseases ,Hemagglutination assay ,Binding Sites ,Influenza A Virus, H5N1 Subtype ,Antigenic shift ,virus diseases ,Antigenic Variation ,QR1-502 ,Influenza A virus subtype H5N1 ,Amino Acid Substitution ,Influenza in Birds ,biology.protein ,Receptors, Virus ,Chickens ,Research Article - Abstract
Highly pathogenic avian influenza (HPAI) viruses of the H5N1 subtype are genetically highly variable and have diversified into multiple phylogenetic clades over the past decade. Antigenic drift is a well-studied phenomenon for seasonal human influenza viruses, but much less is known about the antigenic evolution of HPAI H5N1 viruses that circulate in poultry. In this study, we focused on HPAI H5N1 viruses that are enzootic to Indonesia. We selected representative viruses from genetically distinct lineages that are currently circulating and determined their antigenic properties by hemagglutination inhibition assays. At least six antigenic variants have circulated between 2003, when H5N1 clade 2.1 viruses were first detected in Indonesia, and 2011. During this period, multiple antigenic variants cocirculated in the same geographic regions. Mutant viruses were constructed by site-directed mutagenesis to represent each of the circulating antigenic variants, revealing that antigenic differences between clade 2.1 viruses were due to only one or very few amino acid substitutions immediately adjacent to the receptor binding site. Antigenic variants of H5N1 virus evaded recognition by both ferret and chicken antibodies. The molecular basis for antigenic change in clade 2.1 viruses closely resembled that of seasonal human influenza viruses, indicating that the hemagglutinin of influenza viruses from different hosts and subtypes may be similarly restricted to evade antibody recognition., IMPORTANCE Highly pathogenic avian influenza (HPAI) H5N1 viruses are responsible for severe outbreaks in both commercial and backyard poultry, causing considerable economic losses and regular zoonotic transmissions to humans. Vaccination is used increasingly to reduce the burden of HPAI H5N1 virus in poultry. Influenza viruses can escape from recognition by antibodies induced upon vaccination or infection through genetic changes in the hemagglutinin protein. The evolutionary patterns and molecular basis of antigenic change in HPAI H5N1 viruses are poorly understood, hampering formulation of optimal vaccination strategies. We have shown here that HPAI H5N1 viruses in Indonesia diversified into multiple antigenic variants, that antigenic differences were due to one or a very few substitutions near the receptor binding site, and that the molecular basis for antigenic change was remarkably similar to that for seasonal human influenza viruses. These findings have consequences for future vaccination and surveillance considerations and contribute to the understanding of the antigenic evolution of influenza viruses.
- Published
- 2014
21. Partial and Full PCR-Based Reverse Genetics Strategy for Influenza Viruses
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Troy C. Sutton, Hongjun Chen, Daniel R. Perez, Jianqiang Ye, Kemin Xu, Andrea Ferrero, Matthew Angel, and Hongxia Shao
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RNA viruses ,Viral Diseases ,viruses ,lcsh:Medicine ,Hemagglutinin Glycoproteins, Influenza Virus ,medicine.disease_cause ,Polymerase Chain Reaction ,Madin Darby Canine Kidney Cells ,law.invention ,Plasmid ,Genes, Reporter ,RNA Polymerase I ,Viral classification ,law ,Emerging Viral Diseases ,lcsh:Science ,Promoter Regions, Genetic ,Polymerase chain reaction ,Multidisciplinary ,biology ,virus diseases ,Amplicon ,Orthomyxoviridae ,Infectious Diseases ,Medicine ,Viral Vectors ,Plasmids ,Research Article ,Biotechnology ,DNA, Complementary ,Green Fluorescent Proteins ,Neuraminidase ,Transfection ,Microbiology ,Vector Biology ,Virus ,Dogs ,Virology ,medicine ,Animals ,Humans ,Biology ,lcsh:R ,biology.organism_classification ,Molecular biology ,Reverse Genetics ,Influenza ,Reverse genetics ,Influenza A virus subtype H5N1 ,HEK293 Cells ,biology.protein ,lcsh:Q - Abstract
Since 1999, plasmid-based reverse genetics (RG) systems have revolutionized the way influenza viruses are studied. However, it is not unusual to encounter cloning difficulties for one or more influenza genes while attempting to recover virus de novo. To overcome some of these shortcomings we sought to develop partial or full plasmid-free RG systems. The influenza gene of choice is assembled into a RG competent unit by virtue of overlapping PCR reactions containing a cDNA copy of the viral gene segment under the control of RNA polymerase I promoter (pol1) and termination (t1) signals - herein referred to as Flu PCR amplicons. Transfection of tissue culture cells with either HA or NA Flu PCR amplicons and 7 plasmids encoding the remaining influenza RG units, resulted in efficient virus rescue. Likewise, transfections including both HA and NA Flu PCR amplicons and 6 RG plasmids also resulted in efficient virus rescue. In addition, influenza viruses were recovered from a full set of Flu PCR amplicons without the use of plasmids.
- Published
- 2012
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22. Prevalence of H9N2 influenza a viruses in poultry in southern China : implications for the emergence of a new pandemic influenza
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Kemin Xu
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Southern china ,business.industry ,medicine ,Human mortality from H5N1 ,Pandemic influenza ,Influenza a ,medicine.disease_cause ,business ,Bioinformatics ,Virology ,Influenza A virus subtype H5N1 - Published
- 2012
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23. Variations in the hemagglutinin of the 2009 H1N1 pandemic virus: potential for strains with altered virulence phenotype?
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Matthew Angel, Daniel R. Perez, Hongxia Shao, Danielle Hickman, Erin M. Sorrell, Jianqiang Ye, Balaji Manicassamy, Haichen Song, Rafael A. Medina, Kemin Xu, Lindomar Pena, Yibin Cai, and Adolfo García-Sastre
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Models, Molecular ,Protein Conformation ,Hemagglutinin Glycoproteins, Influenza Virus ,medicine.disease_cause ,Mice ,Influenza A Virus, H1N1 Subtype ,Influenza A virus ,Biology (General) ,Virology/Virulence Factors and Mechanisms ,Cells, Cultured ,0303 health sciences ,Mice, Inbred BALB C ,biology ,Virulence ,Phenotype ,Virology/Virus Evolution and Symbiosis ,3. Good health ,Mice, Inbred DBA ,Virology/Animal Models of Infection ,Female ,Research Article ,QH301-705.5 ,Immunology ,Hemagglutinin (influenza) ,Viral quasispecies ,Microbiology ,Virus ,Virology/Emerging Viral Diseases ,03 medical and health sciences ,Dogs ,Virology ,Genetic variation ,Influenza, Human ,Genetics ,medicine ,Animals ,Humans ,Molecular Biology ,Pandemics ,Genetic Association Studies ,030304 developmental biology ,030306 microbiology ,Ferrets ,Genetic Variation ,RC581-607 ,Reverse genetics ,biology.protein ,Parasitology ,Immunologic diseases. Allergy - Abstract
A novel, swine-origin influenza H1N1 virus (H1N1pdm) caused the first pandemic of the 21st century. This pandemic, although efficient in transmission, is mild in virulence. This atypical mild pandemic season has raised concerns regarding the potential of this virus to acquire additional virulence markers either through further adaptation or possibly by immune pressure in the human host. Using the mouse model we generated, within a single round of infection with A/California/04/09/H1N1 (Ca/04), a virus lethal in mice—herein referred to as mouse-adapted Ca/04 (ma-Ca/04). Five amino acid substitutions were found in the genome of ma-Ca/04: 3 in HA (D131E, S186P and A198E), 1 in PA (E298K) and 1 in NP (D101G). Reverse genetics analyses of these mutations indicate that all five mutations from ma-Ca/04 contributed to the lethal phenotype; however, the D131E and S186P mutations—which are also found in the 1918 and seasonal H1N1 viruses—in HA alone were sufficient to confer virulence of Ca/04 in mice. HI assays against H1N1pdm demonstrate that the D131E and S186P mutations caused minor antigenic changes and, likely, affected receptor binding. The rapid selection of ma-Ca/04 in mice suggests that a virus containing this constellation of amino acids might have already been present in Ca/04, likely as minor quasispecies., Author Summary The 19th century experienced three major influenza pandemics: the Spanish flu of 1918 (H1N1), the Asian flu of 1957 (H2N2) and the Hong Kong flu of 1968 (H3N2). These pandemics were introduced into the human population through the accumulation of avian and human influenza genes (genetic reassortment), creating with each pandemic a novel influenza virus, one that the human population had not been exposed to. These pandemics were associated with high morbidity and mortality; the 1918 pandemic was responsible for an estimated 40 million deaths. In April 2009, a novel, swine-origin influenza H1N1 virus (H1N1pdm) caused the first influenza pandemic of the 21st century. This pandemic was a result of genetic reassortment between not only human and avian influenza genes, but also swine influenza genes. This H1N1 pandemic, although efficient in human-to-human transmission, differed greatly from the previous pandemics in its mild virulence. This atypical mild pandemic season has raised concerns regarding the potential of this virus to become more virulent. Using a mouse model, we were able to demonstrate that this pandemic strain is amenable to mutations that lead to a more virulent virus.
- Published
- 2010
24. Intranasal Delivery of an IgA Monoclonal Antibody Effective against Sublethal H5N1 Influenza Virus Infection in Mice
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Daniel R. Perez, Matthew Angel, Hongxia Shao, Danielle Hickman, Ron A. M. Fouchier, Kemin Xu, Jianqiang Ye, Haichen Song, Yibin Cai, Aijian Qin, and Virology
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Microbiology (medical) ,Time Factors ,medicine.drug_class ,Clinical Biochemistry ,Immunology ,Monoclonal antibody ,medicine.disease_cause ,Virus ,Neutralization ,Microbiology ,Mice ,Orthomyxoviridae Infections ,SDG 3 - Good Health and Well-being ,Neutralization Tests ,Immunity ,medicine ,Influenza A virus ,Animals ,Immunology and Allergy ,Administration, Intranasal ,Mice, Inbred BALB C ,Hemagglutination assay ,Influenza A Virus, H5N1 Subtype ,biology ,Antibodies, Monoclonal ,virus diseases ,Hemagglutination Inhibition Tests ,Survival Analysis ,Virology ,Influenza A virus subtype H5N1 ,Immunoglobulin A ,biology.protein ,Female ,Microbial Immunology ,Immunotherapy ,Antibody - Abstract
Highly pathogenic avian H5N1 influenza viruses are endemic in poultry in Asia and pose a pandemic threat to humans. Since the deployment of vaccines against a pandemic strain may take several months, adequate antiviral alternatives are needed to minimize the effects and the spread of the disease. Passive immunotherapy is regarded as a viable alternative. Here, we show the development of an IgA monoclonal antibody (DPJY01 MAb) specific to H5 hemagglutinin. The DPJY01 MAb showed a broad hemagglutination inhibition (HI) profile against Asian H5N1 viruses of clades 0, 1.0, 2.1, 2.2, and 2.3 and also against H5 wild bird influenza viruses of the North American and Eurasian lineages. DPJY01 MAb displayed also high neutralization activity in vitro and in vivo . In mice, DPJY01 MAb provided protection via a single dose administered intranasally before or after inoculation with a sublethal dose of H5N1 viruses of clades 1.0 and 2.2. Pretreatment with 50 mg of DPJY01 MAb kg of body weight at either 24, 48, or 72 h before highly pathogenic H5N1 virus (A/Vietnam/1203/2004 [H5N1]) inoculation resulted in complete protection. Treatment with 50 mg/kg at either at 24, 48, or 72 h after H5N1 inoculation provided 100%, 80%, and 60% protection, respectively. These studies highlight the potential use of DPJY01 MAb as an intranasal antiviral treatment for H5N1 influenza virus infections.
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- 2010
25. The Deformation Characteristics and Effect of Processing Parameters on the Microstructure of 7075 Al Shell Part Manufactured by Rotating Backward Extrusion
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Ning Guo, Shuchang Li, Fafa Yan, Zhen Wang, Kemin Xue, Rou Wang, and Wenfang Xing
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7075 Al alloy ,rotating backward extrusion ,severe plastic deformation ,microstructure ,Mining engineering. Metallurgy ,TN1-997 - Abstract
Rotating backward extrusion (RBE) is known as a new severe plastic deformation technology that effectively combines the features of conventional backward extrusion (CBE) and torsion deformation. In this study, 7075 Al alloy shell parts were successfully prepared by CBE and RBE with a different number of revolutions (N = 5, 10, 15, 25, 50) at 410 °C. The effects of the RBE process on the grain refinement, precipitates and properties of extruded parts were revealed, and the deformation characteristics were compared with CBE. The results showed that the RBE process could greatly eliminate the dead deformation zone at the bottom of the CBE section and significantly improved the comprehensive strain level of the material due to the addition of severe torsional deformation via an open punch. The grain refinement feature of RBE parts showed a gradient distribution that continuously weakened from the inner wall to the outer wall with decreasing compressive and torsional stress. Increasing the number of revolutions significantly promoted the level of grain refinement, the grain refinement range, and effectively broke down and refined the coarse insoluble Fe-rich phases of the extruded parts. It was revealed that the finest grain size of approximately 1.3 μm could be obtained in the inner wall region when N was increased to 25, which was linked to the comprehensive effects of continuous dynamic recrystallization and geometric dynamic recrystallization. RBE greatly promoted an improvement in properties of the extruded parts. After T6 treatment, the microhardness of the fine-grained region of the RBE (25 N) part increased to ~192–197 HV, compared with ~180 HV in the initial T6-extruded state.
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- 2022
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26. Phylogenetic Analysis of H6 Influenza Viruses Isolated from Rosy-Billed Pochards (Netta peposaca) in Argentina Reveals the Presence of Different HA Gene Clusters.
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Rimondi, Agustina, Kemin Xu, Isabel Craig, Maria, Hongxia Shao, Ferreyra, Hebe, Rago, Maria Virginia, Romano, Marcelo, Uhart, Marcela, Sutton, Troy, Ferrero, Andrea, Perez, Daniel R., and Pereda, Ariel
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INFLUENZA A virus , *RESPIRATORY infections , *WATER birds , *HEMAGGLUTININ - Abstract
Until recently, influenza A viruses from wild waterfowl in South America were rarely isolated and/or characterized. To explore the ecology of influenza A viruses in this region, a long-term surveillance program was established in 2006 for resident and migratory water birds in Argentina. We report the characterization of 5 avian influenza viruses of the H6 hemagglutinin (HA) subtype isolated from rosy-billed pochards (Netta peposaca). Three of these viruses were paired to an N2 NA subtype, while the other two were of the N8 subtype. Genetic and phylogenetic analyses of the internal gene segments revealed a close relationship with influenza viruses from South America, forming a unique clade and supporting the notion of independent evolution from influenza A viruses in other latitudes. The presence of NS alleles A and B was also identified. The HA and NA genes formed unique clades separate from North American and Eurasian viruses, with the exception of the HA gene of one isolate, which was more closely related to the North American lineage, suggesting possible interactions between viruses of North American and South American lineages. Animal studies suggested that these Argentine H6 viruses could replicate and transmit inefficiently in chickens, indicating limited adaptation to poultry. Our results highlight the importance of continued influenza virus surveillance in wild birds of South America, especially considering the unique evolution of these viruses. [ABSTRACT FROM AUTHOR]
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- 2011
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27. Molecular Basis for Broad Neuraminidase Immunity: Conserved Epitopes in Seasonal and Pandemic H1N1 as Well as H5N1 Influenza Viruses.
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Hongquan Wan, Jin Gao, Kemin Xu, Hongjun Chen, Couzens, Laura K., Rivers, Katie H., Easterbrook, Judy D., Kevin Yang, Lei Zhong, Rajabi, Mohsen, Jianqiang Ye, Sultana, Ishrat, Xiu-Feng Wan, Xiufan Liu, Perez, Daniel R., Taubenberger, Jeffery K., and Eichelberger, Maryna C.
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NEURAMINIDASE , *EPITOPES , *H1N1 influenza , *H5N1 Influenza , *PUBLIC health , *IMMUNITY - Abstract
Influenza A viruses, including H1N1 and H5N1 subtypes, pose a serious threat to public health. Neuraminidase (NA)-related immunity contributes to protection against influenza virus infection. Antibodies to the N1 subtype provide protection against homologous and heterologous H1N1 as well as H5N1 virus challenge. Since neither the strain-specific nor conserved epitopes of N1 have been identified, we generated a panel of mouse monoclonal antibodies (MAbs) that exhibit different reactivity spectra with H1N1 and H5N1 viruses and used these MAbs to map N1 antigenic domains Weidentified 12 amino acids essential for MAbbinding to the NAof a recent seasonal H1N1 virus, A/Brisbane/59/2007. Of these, residues 248, 249, 250, 341, and 343 are recognized by strain-specific group A MAbs, while residues 273, 338, and 339 are within conserved epitope(s), which allows cross-reactive group B MAbs to bind the NAs of seasonal H1N1 and the 1918 and 2009 pandemic (09pdm) H1N1 as well as H5N1 viruses. A single dose of group B MAbs administered prophylactically fully protected mice against lethal challenge with seasonal and 09pdm H1N1 viruses and resulted in significant protection against the highly pathogenic wild-type H5N1 virus. Another three N1 residues (at positions 396, 397, and 456) are essential for binding of cross-reactive group E MAbs, which differ from group B MAbs in that they do not bind 09pdm H1N1 viruses. The identification of conserved N1 epitopes reveals the molecular basis for NA-mediated immunity between H1N1 and H5N1 viruses and demonstrates the potential for developing broadly protective NA-specific antibody treatments for influenza. [ABSTRACT FROM AUTHOR]
- Published
- 2013
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