Zhengjie Xu

Publications (5)2.06 Total impact

• Article: Phosphatidylinositol 3-kinase inhibitor suppresses inducible nitric oxide synthase expression in bronchiole epithelial cells in asthmatic rats.

  Xiaodong Xia, Xiaoguang Hu, Hui Xu, Liqin Wu, Yuanrong Dai, Lei Yang, Zhengjie Xu
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  ABSTRACT: Inducible nitric oxide synthase (iNOS) is known to produce nitric oxide (NO), which is a main contributor to asthmatic airway inflammation. Recent studies have shown that phosphatidylinositol 3-kinase (PI3K) is ubiquitously expressed in airway epithelial cells and its inhibition could relieve airway inflammation and hyperresponsiveness. This study aimed to explore the interaction of PI3K and NO signaling in allergic asthma. We investigated the effects of PI3K inhibitor wortmannin on iNOS expression in bronchiole epithelial cells and NO, IL-4 and IFN-γ levels in lung tissues of asthmatic rat model, which was prepared by 10% OVA solution sensitization and 1% OVA aerosol challenge. Our results showed that the ratio of eosinophils to total cells in BALF, PI3K activity, NO and IL-4 levels in lung tissues was increased after OVA sensitization and challenge, but then was attenuated by the administration of wortmannin. In contrast, IFN-γ level in lung tissues was decreased after OVA sensitization and challenge and increased after the administration of wortmannin. The expression of iNOS protein in bronchiole epithelial cells, iNOS mRNA level and iNOS activity in lung tissues was markedly upregulated after OVA sensitization and challenge, but the upregulation was significantly antagonized by wortmannin. Taken together, these data provide evidence that PI3K functions upstream to modulate iNOS/NO signaling, which then promotes the development of airway inflammation in asthmatic animal model. PI3K inhibitor wortmannin could lead to reduced iNOS expression and NO production, therefore inhibiting airway inflammatory responses.
  Molecular and Cellular Biochemistry 08/2011; 359(1-2):293-9. · 2.06 Impact Factor
• Source

  Available from: ArXiv

  Article: The Benjamin-Ono Hierarchy with Asymptotically Reflectionless Initial Data in the Zero-Dispersion Limit

  Peter D. Miller, Zhengjie Xu
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  ABSTRACT: We study the Benjamin-Ono hierarchy with positive initial data of a general type, in the limit when the dispersion parameter tends to zero. We establish simple formulae for the limits (in appropriate weak or distributional senses) of an infinite family of simultaneously conserved densities in terms of alternating sums of branches of solutions of the inviscid Burgers hierarchy.
  01/2011;
• Source

  Available from: ArXiv

  Article: On the zero-dispersion limit of the Benjamin-Ono Cauchy problem for positive initial data

  Peter D. Miller, Zhengjie Xu
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  ABSTRACT: We study the Cauchy initial-value problem for the Benjamin-Ono equation in the zero-disperion limit, and we establish the existence of this limit in a certain weak sense by developing an appropriate analogue of the method invented by Lax and Levermore to analyze the corresponding limit for the Korteweg-de Vries equation. Comment: 54 pages, 11 figures
  02/2010;
• Article: The inhibition of pulmonary vessel remodeling by carbon monoxide system in rats with chronic pulmonary heart disease.

  Xiaoying Huang, Liangxing Wang, Shaoxian Chen, Zhengjie Xu, Qunji Wang, Xiaofang Fan
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  ABSTRACT: To study the effect of carbon monoxide on pulmonary vessel remodeling of chronic pulmonary heart disease. Thirty-six sprague-dawley rats were randomly divided into three groups: control group, and hypoxic hypercapnic group, and hypoxic hypercapnia + hemin group. Blood CO concentration (COHb%), activity of HO-1 in blood serum and lung homogenate, pulmonary arteriole micromorphometric index, HO-1 and HO-1 mRNA were measured. (1) mPAP and RV/(LV + S) were (20.1 +/- 0.8) mm Hg and (35.5 +/- 1.7)% in hypoxic hypercapnic group, they were significantly higher than those of control group's (15.3 +/- 1.4) mm Hg, (26.7 +/- 1.7)%, and those of hypoxic hypercapnia + hemin (activator of HO-1) group's (16.5 +/- 3.7) mm Hg, (30.2 +/- 1.6)% (P < 0.01). (2) Pulmonary arteriole micromorphometric index in rats of hypoxic hypercapnic group were significantly higher than those of control group and hypoxic hypercapnia + hemin group (P < 0.01). (3) Blood CO concentration, activity of HO-1 in blood serum and lung homogenate, content of HO-1 and HO-1 mRNA in pulmonary arterioles in rats of hypoxic hypercapnic group were (2.1 +/- 0.9)%, (73 +/- 18) nmol.L(-1).h(-1), (1 751 +/- 311) pmol.mg(-1).h(-1), 0.191 +/- 0.012 and 0.301 +/- 0.017, were significantly higher than those of control group: (0.5 +/- 0.3)%, (25 +/- 8) nmol.L(-1).h(-1), (385 +/- 46) pmol.mg(-1).h(-1), 0.059 +/- 0.005, 0.131 +/- 0.011, but were significantly lower than those of hypoxic hypercapnia + hemin group: (4.9 +/- 2.1)%, (132 +/- 39) nmol.L(-1).h(-1), (2 849 +/- 426) pmol.mg(-1).h(-1), 0.272 +/- 0.013, 0.339 +/- 0.020 (P < 0.01). (4) Correlation analysis revealed that the relationship between carbon monoxide system and pulmonary arteriole micromorphometric index was significantly negative (P < 0.01). Up-regulation of endogenous carbon monoxide system can inhibit pulmonary vessel remodeling in rats with chronic pulmonary heart disease induced by hypoxia and hypercapnia.
  Zhonghua jie he he hu xi za zhi = Zhonghua jiehe he huxi zazhi = Chinese journal of tuberculosis and respiratory diseases 07/2002; 25(7):408-11.
• Source

  Available from: umich.edu

  Article: Asymptotic Analysis and Numerical Analysis of the Benjamin-Ono Equation

  Zhengjie Xu
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  ABSTRACT: The Benjamin-Ono equation is an integrable partial integro-differential equation which attracts much attention due to its application in modeling of the internal gravity waves in deep water and the ``morning glory cloud" in Northeastern Australia. In this dissertation, we first analyze the zero dispersion limit of the Cauchy problem of the Benjamin-Ono equation and give the first rigorous results. We demonstrate existence of the zero dispersion limit in the weak L2(R) sense and show this limit is equal to the signed sum of the branches of the multivalued solution of the inviscid Burgers equation with the same initial condition. Generalizations of these results are also given in this dissertation by using the formula of the $N$-soliton solutions of the higher order BO equations obtained by Matsuno. Moreover, we study three different numerical methods: the Fourier pseudospectral method, the Radial Basis Function method and the Christov method which are applied to solve the Benjamin-Ono equation. A comparison among the three methods is included. In the end, we also numerically illustrate and verify our theoretical results and study the traveling wave solutions of the cubic Benjamin-Ono equation.