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Search Results: 1 - 10 of 6136 matches for " Xiqian Lan "
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HIV-1-Infected and Immune-Activated Macrophages Induce Astrocytic Differentiation of Human Cortical Neural Progenitor Cells via the STAT3 Pathway
Hui Peng, Lijun Sun, Beibei Jia, Xiqian Lan, Bing Zhu, Yumei Wu, Jialin Zheng
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0019439
Abstract: Diminished adult neurogenesis is considered a potential mechanism in the pathogenesis of HIV-1-associated dementia (HAD). In HAD, HIV-1-infected and immune-activated brain mononuclear phagocytes (MP; perivascular macrophages and microglia) drive central nervous system (CNS) inflammation and may alter normal neurogenesis. We previously demonstrated HIV-1-infected and lipopolysaccharide (LPS) activated monocyte-derived macrophages (MDM) inhibit human neural progenitor cell (NPC) neurogenesis, while enhancing astrogliogenesis through the secretion of the inflammatory cytokines such as tumor necrosis factor-alpha (TNF-α), in vitro and in vivo. Here we further test the hypothesis that HIV-1-infected/activated MDM promote NPC astrogliogenesis via activation of the transcription factor signal transducer and activator of transcription 3 (STAT3), a critical factor for astrogliogenesis. Our results show that LPS-activated MDM-conditioned medium (LPS-MCM) and HIV-infected/LPS-activated MDM-conditioned medium (LPS+HIV-MCM) induced Janus kinase 1 (Jak1) and STAT3 activation. Induction of the Jak-STAT3 activation correlated with increased glia fibrillary acidic protein (GFAP) expression, demonstrating an induction of astrogliogenesis. Moreover, STAT3-targeting siRNA (siSTAT3) decreased MCM-induced STAT3 activation and NPC astrogliogenesis. Furthermore, inflammatory cytokines (including IL-6, IL-1β and TNF-α) produced by LPS-activated and/or HIV-1-infected MDM may contribute to MCM-induced STAT3 activation and astrocytic differentiation. These observations were confirmed in severe combined immunodeficient (SCID) mice with HIV-1 encephalitis (HIVE). In HIVE mice, siRNA control (without target sequence, sicon) pre-transfected NPCs injected with HIV-1-infected MDM showed more astrocytic differentiation and less neuronal differentiation of NPCs as compared to NPC injection alone. siSTAT3 abrogated HIV-1-infected MDM-induced astrogliogenesis of injected NPCs. Collectively, these observations demonstrate that HIV-1-infected/activated MDM induces NPC astrogliogenesis through the STAT3 pathway. This study generates important data elucidating the role of brain inflammation in neurogenesis and may provide insight into new therapeutic strategies for HAD.
TNF-α Affects Human Cortical Neural Progenitor Cell Differentiation through the Autocrine Secretion of Leukemia Inhibitory Factor
Xiqian Lan, Qiang Chen, Yongxiang Wang, Beibei Jia, Lijun Sun, Jialin Zheng, Hui Peng
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0050783
Abstract: Proinflammatory cytokine tumor necrosis factor-alpha (TNF-α) is a crucial effector of immune responses in the brain that participates in the pathogenesis of several acute and chronic neurodegenerative disorders. Accumulating evidence has suggested that TNF-α negatively regulates embryonic and adult neurogenesis. However, the effect of TNF-α on cell fate decision in human neural progenitor cells (NPCs) has rarely been studied. Our previous studies have shown that recombinant TNF-α enhances astrogliogenesis and inhibits neurogenesis of human NPCs through the STAT3 (signal transducer and activator of transcription 3) pathway. In the current study, we further elucidated the specific mechanism involved in TNF-α-induced astrogliogenesis. We found that TNF-α activated STAT3 at delayed time points (6 h and 24 h), whereas conditioned medium collected from TNF-α-treated NPCs induced an immediate STAT3 activation. These data suggest TNF-α plays an indirect role on STAT3 activation and the subsequent NPC differentiation. Further, we showed that TNF-α induced abundant amounts of the IL-6 family cytokines, including Leukemia inhibitory factor (LIF) and Interleukin 6 (IL-6), in human NPCs. TNF-α-induced STAT3 phosphorylation and astrogliogenesis were abrogated by the addition of neutralizing antibody for LIF, but not for IL-6, revealing a critical role of autocrine secretion of LIF in TNF-α-induced STAT3 activation and astrogliogenesis. This study generates important data elucidating the role of TNF-α in neurogenesis and may provide insight into new therapeutic strategies for brain inflammation.
Morphine Induces Albuminuria by Compromising Podocyte Integrity
Xiqian Lan, Partab Rai, Nirupama Chandel, Kang Cheng, Rivka Lederman, Moin A. Saleem, Peter W. Mathieson, Mohammad Husain, John T. Crosson, Kalpna Gupta, Ashwani Malhotra, Pravin C. Singhal
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0055748
Abstract: Morphine has been reported to accelerate the progression of chronic kidney disease. However, whether morphine affects slit diaphragm (SD), the major constituent of glomerular filtration barrier, is still unclear. In the present study, we examined the effect of morphine on glomerular filtration barrier in general and podocyte integrity in particular. Mice were administered either normal saline or morphine for 72 h, then urine samples were collected and kidneys were subsequently isolated for immunohistochemical studies and Western blot. For in vitro studies, human podocytes were treated with morphine and then probed for the molecular markers of slit diaphragm. Morphine-receiving mice displayed a significant increase in albuminuria and showed effacement of podocyte foot processes. In both in vivo and in vitro studies, the expression of synaptopodin, a molecular marker for podocyte integrity, and the slit diaphragm constituting molecules (SDCM), such as nephrin, podocin, and CD2-associated protein (CD2AP), were decreased in morphine-treated podocytes. In vitro studies indicated that morphine modulated podocyte expression of SDCM through opiate mu (MOR) and kappa (KOR) receptors. Since morphine also enhanced podocyte oxidative stress, the latter seems to contribute to decreased SDCM expression. In addition, AKT, p38, and JNK pathways were involved in morphine-induced down regulation of SDCM in human podocytes. These findings demonstrate that morphine has the potential to alter the glomerular filtration barrier by compromising the integrity of podocytes.
Genome-Wide Transcriptional Response of Silkworm (Bombyx mori) to Infection by the Microsporidian Nosema bombycis
Zhengang Ma, Chunfeng Li, Guoqing Pan, Zhihong Li, Bing Han, Jinshan Xu, Xiqian Lan, Jie Chen, Donglin Yang, Quanmei Chen, Qi Sang, Xiaocun Ji, Tian Li, Mengxian Long, Zeyang Zhou
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0084137
Abstract: Microsporidia have attracted much attention because they infect a variety of species ranging from protists to mammals, including immunocompromised patients with AIDS or cancer. Aside from the study on Nosema ceranae, few works have focused on elucidating the mechanism in host response to microsporidia infection. Nosema bombycis is a pathogen of silkworm pébrine that causes great economic losses to the silkworm industry. Detailed understanding of the host (Bombyx mori) response to infection by N. bombycis is helpful for prevention of this disease. A genome-wide survey of the gene expression profile at 2, 4, 6 and 8 days post-infection by N. bombycis was performed and results showed that 64, 244, 1,328, 1,887 genes were induced, respectively. Up to 124 genes, which are involved in basal metabolism pathways, were modulated. Notably, B. mori genes that play a role in juvenile hormone synthesis and metabolism pathways were induced, suggesting that the host may accumulate JH as a response to infection. Interestingly, N. bombycis can inhibit the silkworm serine protease cascade melanization pathway in hemolymph, which may be due to the secretion of serpins in the microsporidia. N. bombycis also induced up-regulation of several cellular immune factors, in which CTL11 has been suggested to be involved in both spore recognition and immune signal transduction. Microarray and real-time PCR analysis indicated the activation of silkworm Toll and JAK/STAT pathways. The notable up-regulation of antimicrobial peptides, including gloverins, lebocins and moricins, strongly indicated that antimicrobial peptide defense mechanisms were triggered to resist the invasive microsporidia. An analysis of N. bombycis-specific response factors suggested their important roles in anti-microsporidia defense. Overall, this study primarily provides insight into the potential molecular mechanisms for the host-parasite interaction between B. mori and N. bombycis and may provide a foundation for further work on host-parasite interaction between insects and microsporidia.
One Case about Primary Pulmonary Squamous Cell Carcinoma ?with Retinal Metastasis
Jinxia LIU, Xiqian GAO, Mindan SUN
- , 2017, DOI: : 10.3779/j.issn.1009-3419.2017.09.11
Abstract: Lung cancer is a common malignant tumor in clinic. Morbidity and mortality are the first place in cancer, which seriously threaten the health of human beings. Due to the lack of effective and specific screening methods, most patients were found already at an advanced stage, and often combined with bone, brain, liver, adrenal and other parts of the metastasis. Symptoms of patient resulted from the primary tumor, metastatic spread, or paraneoplastic syndrome commonly cause the medical attention. For the syndrome related to the distant metastatic spread as the first manifestation, diagnosis would be a challenge. Retinal metastasis is very rare as the first symptom of squamous cell carcinoma of the lung. This paper reviewed a case, in which a patient developed the retinal metastasis as the inital presentation. After systemic evaluation, our patient was managed in multidisciplinary treatments, including surgery and chemotherapy. Now, the patient has a good short-term prognosis and is still in fellow-up condition. Later, we summarized the characteristics of the diagnosis and treatment of this case and provided experience for clinicians. At the same time, reviewing the relevant literature on tumor metastasis provides a window for our understanding of the rare manifestations of lung cancer.
On the Evaluation of Performance System Incorporating “Green Credit” Policies in China’s Financial Industry  [PDF]
Lan Xu
Journal of Financial Risk Management (JFRM) , 2013, DOI: 10.4236/jfrm.2013.22005

The main work of this paper is aimed, through utilizing the two-stage optimization theory, to estimate the green distance functions and Malmquist green growth indexes for the China’s main commercial banks and relevant financial institutions, and to further set up an overall appraisal index system to assess their performance in implementing the “Green Credit” principles. The paper also analyzes effects of the “Green Credit” policies influential on revenue achievements, as well as performs a decomposition analysis of the above impacts. The carry-outs of the paper may serve as useful references and guiding means in achievingChina’s economic transitional strategies of sustainable development.

Research on the Technology Enterprise Performance Evaluation Index System  [PDF]
Lan Fu
iBusiness (IB) , 2013, DOI: 10.4236/ib.2013.53B002

The purpose of this essay is to design a framework of a performance evaluation system which is subject to the characteristics of China technology enterprises. It based on the analyzing the principles and significance of the performance evaluation system of technology enterprises. The framework will promote the standardize management of technology enterprises of China.

3-D Modelling of the Confederation Bridge Using Data of Full Scale Tests  [PDF]
Lan Lin
Open Journal of Civil Engineering (OJCE) , 2013, DOI: 10.4236/ojce.2013.33B004

Long-span bridges are special structures that require advanced analysis techniques to examine their performance. This paper presents a procedure developed to model the Confederation Bridge using 3-D beam elements. The model was validated using the data collected before the opening of the bridge to the public. The bridge was instrumented to conduct fullscale static and dynamic tests. The static tests were to measure the deflection of the bridge pier while the dynamic tests to measure the free vibrations of the pier due to a sudden release of the static load. Confederation Bridge is one of the longest reinforced concrete bridges in the world. It connects the province of Prince Edward Island and the province of New Brunswick in Canada. Due to its strategic location and vital role as a transportation link between these two provinces, it was designed using higher safety factors than those for typical highway bridges. After validating the present numerical model, a procedure was developed to evaluate the performance of similar bridges subjected to traffic and seismic loads. It is of interest to note that the foundation stiffness and the modulus of elasticity of the concrete have significant effects on the structural responses of the Confederation Bridge.

Research on the Development Strategy of Logistics Firms in China  [PDF]
Lan Wang
Open Journal of Social Sciences (JSS) , 2014, DOI: 10.4236/jss.2014.29042

The logistics industry has attracted wide attention as an important industry that supports economic development. Most of Chinese logistics enterprises are transferred from traditional transportation and warehousing business. Their information integration and mining capacity is insufficient. The basis of weak competitiveness of the traditional logistics industry needs to be improved. By analyzing the driven factors of modern logistics industry, the paper further discusses Chinese logistics enterprises’ problems and analyzes the case of X company to describe the business strategy of modern logistics firms.

Research on the Construction of the Emergency Logistics System in the Large State-Owned Enterprises  [PDF]
Lan Fu
Open Journal of Social Sciences (JSS) , 2014, DOI: 10.4236/jss.2014.29010

The purpose of this essay is to discuss some issues about the government how to improve the construction of the infrastructures, transportation system and communication system and how to enhance the capability of resisting natural disaster as the disaster comes. Emergent logistics information system not only can help the power group to collect information and forecast the future disaster but also has the function of decision-making and supporting. Furthermore the emergency logistics information system can assist the power group to decrease the loss from the disaster.

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