De-Xi Chen

Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Peping, Beijing, China

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Publications (14)6.08 Total impact

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    ABSTRACT: To study the clinical outcome of antiviral therapy in hepatitis B-related decompensated cirrhotic patients. Three hundred and twelve patients with decompensated hepatitis B cirrhosis were evaluated in a prospective cohort. With two years of follow-up, 198 patients in the group receiving antiviral therapy with nucleos(t)ide analogues and 39 patients in the control group without antiviral treatment were analysed. Among the antiviral treatment patients, 162 had a complete virological response (CVR), and 36 were drug-resistant (DR). The two-year cumulative incidence of hepatocellular carcinoma (HCC) in the DR patients (30.6%) was significantly higher than that in both the CVR patients (4.3%) and the control group (10.3%) (P < 0.001). Among the DR patients in particular, the incidence of HCC was 55.6% (5/9) in those who failed rescue therapy, which was extremely high. The rtA181T mutation was closely associated with rescue therapy failure (P = 0.006). The Child-Pugh scores of the CVR group were significantly decreased compared with the baseline (8.9 ± 2.3 vs 6.0 ± 1.3, P = 0.043). This study showed that antiviral drug resistance increased the risk of HCC in decompensated hepatitis B-related cirrhotic patients, especially in those who failed rescue therapy.
    World Journal of Gastroenterology 12/2013; 19(45):8373-81. · 2.55 Impact Factor
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    ABSTRACT: A double mutant with streaked leaf and abnormal floret was found and temporarily named streaked leaf and floral organ number mutant (st-fon). For this mutant, besides white streak appeared on culm, leaves and panicles, the number of floral organs increased and florets cracked. The extreme phenotype was that several small florets grew from one floret or branch rachis in small florets extended and developed into panicles. By using transmission electron microscope to observe the ultrastructure of white histocytes of leaves at the seedling stage, the white tissues which showed abnormal plastids, lamellas and thylakoids could not develop into normal chloroplast, and the development of chloroplast was blocked at the early growth stage of plastid. Scanning electron microscope and paraffin section were also used to observe the development of floral organs, and the results indicated that the development of floral meristem was out of order and unlimited, whereas in the twisty leaves, vascular bundle sheath cells grew excessively, or some bubbly cells increased. Genetic analyses carried out by means of cross and backcross with four normal-leaf-color materials revealed that the mutant is of cytoplasm inheritance.
    Rice Science 01/2013; 20(4):267–275.
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    ABSTRACT: CD4+ central memory T cells play a critical role in the pathogenesis of simian immunodeficiency virus disease, and the CCR5 density on the surface of CD4 T cells is an important factor in human immunodeficiency virus (HIV)-1 disease progression. We hypothesized that quantifying central memory cells and CCR5 expression in the early stages of HIV-infection could provide useful prognostic information. We enrolled two different groups of acute HIV-infected subjects. One group progressed to CD4 T cell numbers below 250 cells/µl within 2 years (CD4 Low group), while the other group maintained CD4 cell counts above 450 cells/µl over 2 years (CD4 High group). We compared the CCR5 levels and percentage of CD4 subsets between the two groups during the 1st year of HIV infection. We found no differences between the two groups regarding the percentage of naïve, central memory and effector memory subsets of CD4 cells during the 1st year of HIV-1 infection. CCR5 levels on CD4+ CM subset was higher in the CD4 Low group compared with the CD4 High group during the 1st year of HIV-1 infection. High CCR5 levels on CD4 central memory cells in acute HIV infection are mostly associated with rapid disease progression. Our data suggest that low CCR5 expression on CD4 central memory cells protects CD4 cells from direct virus infection and favors the preservation of CD4(+) T cell homeostasis.
    PLoS ONE 01/2012; 7(11):e49526. · 3.53 Impact Factor
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    ABSTRACT: Skin lesions are often associated with human immunodeficiency virus (HIV) infection, reflecting the immunocompromised status of the individual. We investigated the relationship between skin lesions and immune function in a retrospective study of 796 Chinese HIV patients with and without highly active antiretroviral therapy (HAART). Of the 651 patients who had not received HAART, we found that 531 (81.6%) had apparent skin lesions. The incidence of infectious skin diseases (fungi, viruses, bacteria, spirochetes and parasites) and non-infectious skin diseases (excluding skin cancer) was 68.8% and 34.9%, respectively. Mean CD4(+) T-cell counts and CD4(+)/CD8(+) ratios were lower in patients with skin lesions than in patients without lesions (178 ± 96/µl vs. 306 ± 189/µl (p < 0.05) and 0.22 vs. 0.34 (p < 0.01), respectively). Candidiasis (25.8%), eczema (19.2%), nodular prurigo (13.8%), dermatophyte infections (10.6%) and herpes zoster (9.4%) were most common in Chinese patients with HIV. Among the 145 patients who had started HAART, there was a significantly lower prevalence of skin diseases (29.0%), although drug eruptions (12.4%) were more commonly observed. These findings indicate that HAART often reduces the incidence of infectious and non-infectious skin lesions in patients with HIV, but can itself be the cause of drug eruptions.
    Acta Dermato-Venereologica 05/2011; 91(5):552-6.
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    ABSTRACT: Resistance to rice blast of transgenic rice lines harboring rice blast resistance gene Pi-d2 transformed from three different expression vectors of pCB6.3kb, pCB5.3kb and pZH01-2.72kb were analyzed. Nine advanced-generation transgenic rice lines with Pi-d2 gene displayed various resistance to 39 rice blast strains, and the highest disease-resistant frequency reached 91.7%. Four early-generation homozygous transgenic lines with Pi-d2 gene exhibited resistance to more than 81.5% of 58 rice blast strains, showing the characteristic of wide-spectrum resistance. The transgenic embryonic calli selected by the crude toxin of rice blast fungus showed that the callus induction rate of immature embryo from transgenic rice plants decreased as the concentration of crude toxin in the culture medium increased. When the concentration of crude toxin reached 40%, the callus induction rate of immature embryo from transgenic lines was 49.3%, and that of the receptor control was 5%. The disease incidence of neck blast of the transgenic rice lines in fields under induction was 0% to 50%, indicating that the rice blast resistance of transgenic rice lines is much higher than that of the receptor control.
    Rice Science 01/2010; 17(3):179-184.
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    ABSTRACT: The gene Pi-d2, conferring gene-for-gene resistance to the Chinese blast strain ZB15, was isolated from a rice variety (Digu) by the map-based cloning strategy. Here, we constructed a control plasmid pZH01-pi-d2tp309 (pZH01-tp309) and three different expression constructs, pCB-Pi-d25.3kb (pCB5.3kb), pCB-Pi-d26.3kb (pCB6.3kb) and pZH01-Pi-d22.72kb (pZH01-2.72kb) of Pi-d2, driven by Pi-d2 gene's own promoter or CaMV35S promoter. These constructs were separately introduced into japonica rice varieties Lijiangxintuanhegu, Taipei 309, Nipponbare and Zhonghua 9 through Agrobacterium-mediated transformation. A total of 150 transgenic rice plants were obtained from the regenerated calli selected on hygromycin. PCR, RT-PCR and Southern-blotting assay showed that the gene of interest had been integrated into rice genome and stably inherited. Thirty-five transgenic lines independently derived from T1 progeny were inoculated with the rice blast strain ZB15. Transformants exhibited resistance to rice blast at various levels. The lesions on the transgenic plant leaves were less severe than those on the controls and the resistance level of transgenic plants harboring the gene of interest from three vectors had no difference. The own promoter of Pi-d2, about 2.2 kb or 3.2 kb, had the similar promoter function as CaMV35S. Field evaluation for three successive years supported the results of artificial trial, and some lines with high resistance to rice leaf blast and neck blast were obtained.
    Rice Science 01/2010; 17(1):19-27.
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    ABSTRACT: To investigate alterations of hyper variable region 1 (HR 1) of mitochondrial DNA Blood cells were (mtDNA) in white blood cells of Chinese Han nationality HIV/AIDS patients. obtained from 47 cases of therapy-naïve HIV/AIDS patients without opportunity infection and DNA were extracted using blood DNA extracted kit. About 600 bp fragments which contain HR 1 were amplified by PCR. Alterations were determined by directed DNA sequencing. There were 124 polymorphism sites in mtDNA HR 1 (nb16024-16383) in 47 HIV/AIDS patients. The alteration rate was 0 to 20.47% (median 5.33%). 36 cases experienced C to T nucleotide change at nt 16 223, and the alteration rate was 70.97%. At nt 16 362, 26 individuals showed T to C nucleotide change and 3 individuals showed T to G alteration, alteration rate was 55.32% (26/47) and 6.38% (3/47) individually. HIV infection may cause more alterations in HR 1 regions.
    Zhonghua shi yan he lin chuang bing du xue za zhi = Zhonghua shiyan he linchuang bingduxue zazhi = Chinese journal of experimental and clinical virology 12/2009; 23(6):446-8.
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    ABSTRACT: OBJECTIVE: To comprehend the latest HIV-I epidemic tendency and the character of V3 loop in MSM population of Beijing. METHODS; The C2-V3 regions of the HIV envelop gene were amplified by nest-PCR and sequenced from 11 HIV-l-infected MSM in Beijing in 2007. The subtype and sequences of V3 loop was analyzed. RESULTS There are 4 subtype B strains, 5 CRF AE, 1 CRFO7BC and 1 CRF15-01B strains within all 11 strains. There are five types of central motifs of the 11 samples, in which GPGR and GPGQ are most common. CONCLUSION: Recombination subtype of HIV-1 are spread extensively in MSM population of Beijing.
    Zhonghua shi yan he lin chuang bing du xue za zhi = Zhonghua shiyan he linchuang bingduxue zazhi = Chinese journal of experimental and clinical virology 08/2009; 23(4):275-7.
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    ABSTRACT: To highly express TAT-HBX-EGFP fusion protein and study its distribution in mouse liver. TAT-HBX-EGFP recombinant vector was constructed and fusion protein was induced by IPTG and expression in BL21; fusion protein was purified by Ni-NTA argarose, then injected into the peritoneal cavity of the mice. Distribution of fusion protein was observed by immunofluorescence. TAT-HBX-EGFP was highly expression in E. coli; HBX could be induced into mouse liver by TAT. HBX protein could be induced into mouse liver by TAT induced peptide.
    Zhonghua shi yan he lin chuang bing du xue za zhi = Zhonghua shiyan he linchuang bingduxue zazhi = Chinese journal of experimental and clinical virology 09/2008; 22(4):287-9.
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    ABSTRACT: To investigate the regulatory effect and significance of transcription factor E2F1 on X-ray repair cross2 complementing 1 (XRCC1). Saos2 cells were transfected with the E2F1 expression vectors (tet-E2F1) and mutated E2F1 expression vectors (tet-132E). XRCC1 promotor luciferase reporter vector was constructed and transfected into Saos2 cells together with E2F1, E2F2, E2F3 and E2F4 expression vectors at different amount. The cells were collected 36 hours post-transfection for luciferase assays and absorbance was read at 570 nm. Cotransfection of increasing amounts of E2F1 expression vector with the XRCC1 promoter-luciferase reporter caused a dose-dependent increase in luciferase activation. In contrast, DNA binding incompetent E2F1 (132E) could not activate the XRCC1 promoter-luciferase reporter. E2F1 could upregulate endogenous XRCC1 expression and stimulate the XRCC1 promoter.
    Zhonghua shi yan he lin chuang bing du xue za zhi = Zhonghua shiyan he linchuang bingduxue zazhi = Chinese journal of experimental and clinical virology 07/2008; 22(3):186-8.
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    ABSTRACT: To characterize the variation in V3 loop of HIV-1 B'strains circulating in Chinese blood donors. The c2-c3 regions of the HIV envelop gene were amplified by nest-PCR from 32 HIV-1-infected blood donors in He Nan province in China. The BIOEDIT and MEGA software are used to analyze the sequences of V3 loop. There are five types of central motifs of the 32 samples, in which GPGR and GPGQ are most common. More variations associated with T tropic/SI phenotype can be seen in AIDS group. The V3 tip motifs of HIV-1B' strains circulating in Chinese blood donors are various, the different characterization of V3 loop between AIDS and asymptomatic patients indicates different biological phenotype and pathogenesis which warrant additional investigation.
    Zhonghua shi yan he lin chuang bing du xue za zhi = Zhonghua shiyan he linchuang bingduxue zazhi = Chinese journal of experimental and clinical virology 03/2008; 22(1):27-9.
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    ABSTRACT: To investigate the expression of K18, Ser-33 and Ser-52 phosphorylated K18 in HBV infected human liver disease and its significance. The expression and localization of K18 and Ser-33, Ser-52 phosphorylated K18 in healthy liver tissue, in liver tissues of patients with post-HBV infection cirrhosis and severe chronic hepatitis were detected by histochemistry. K18, Ser-33 and Ser-52 phosphorylated K18 were expressed in normal liver cells, in liver tissues of cirrhosis patients and severe chronic hepatitis cases. The expression of K18 in the liver cells from the 3 different sources had no significant difference in levels. Ser-33 and Ser-52 phosphorylated K18 were expressed in normal liver cells, in liver tissues of cirrhosis patients chronicity HBV hepatitis and severe chronic hepatitis cases. Ser-33 and Ser-52 located around cytoplasmic membrane, diffused into cytoplasm and expressed at a higher levels in cirrhosis and severe chronic hepatitis. The expression levels of Ser-33 and Ser-52 phosphorylated K18 increased along with the progression of HBV infected human liver disease. The phosphorylation of K18 could be a marker of progression of HBV infected human liver disease.
    Zhonghua shi yan he lin chuang bing du xue za zhi = Zhonghua shiyan he linchuang bingduxue zazhi = Chinese journal of experimental and clinical virology 10/2007; 21(3):220-2.
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    ABSTRACT: To clone human CCL3L1 cDNA and to express and purify the glutathione-S-transferase (GST) fusion protein and human CCL3L1 protein. Total RNA was isolated from breast cancer cell line MCF7. CCL3L1 cDNA including open reading frame was obtained by RT-PCR. PCR product was digested with EcoR I and cloned into the pGEX-4T-1 vector. The plasmids from positive clone was prepared and sequenced to confirm the CCL3L1 in correct fusion form. pGEX-4T-CCL3L1 was transfected to BL21 E. coli via isopropyl-beta-D-thiogalactoside (IPTG) induction to produce GST-CCL3L1 fusion protein, which was further detected by SDS-PAGE and Western blotting. As shown and confirmed by restriction endonuclease digestion analysis, CCL3L1 was correctly inserted into pGEX-4T-1 vector. The expressed fusion protein had a relative molecular weight of approximately 34 kD. GST-CCL3L1 fusion protein can be successfully expressed using appropriate vector.
    Zhongguo yi xue ke xue yuan xue bao. Acta Academiae Medicinae Sinicae 11/2006; 28(5):642-6.
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    ABSTRACT: Potent combination antiretroviral therapy (cART) has significantly improved the life expectancy of people living with human immunodeficiency virus (HIV), but it has many side effects such as lipodystrophy (LD), hepatic steatosis, and lactic acidosis. Nucleoside reverse transcriptase inhibitors (NRTIs) could damage the mitochondria by inhibiting the human DNA polymerase gamma, leading to mtDNA deletion. However, it remains uncertain whether NRTIs could induce the hypervariable region (HV) mutations of the D loop of mitochondria in Chinese HIV/AIDS patients, and whether that effect is different between individuals with and without LD. Hereby, 30 Chinese AIDS patients who were receiving antiretroviral drugs were recruited, among which 16 had symptomatic LD and 14 did not. Blood samples were collected prior to and after 96 weeks of treatment. Total DNA was extracted from peripheral blood mononuclear cells (PBMCs). Fragments of 728 bp in length containing HV2 were amplified by standard polymerase chain reaction (PCR). Direct DNA-sequencing analysis techniques were used to detect mitochondrial sequence variants between paired longitudinal samples. Alterations were compared with the revised Cambridge Reference Sequence (rCRS) to determine mutation or polymorphism. Results showed that two years after ART, totally seven cases exhibited sequence variations, ve individuals showed 73 → G revised variation (two with and three without LD), while two cases of LD were found to have other nucleotide alterations. There was no new alteration in individuals without LD. In conclusion, NRTIs could induce mutation of mtDNA HV2, which might contribute to the development of LD. Keywordsnucleoside reverse transcriptase inhibitors-human immunodeficiency virus-mitochondrial DNA-D loop-mutation
    Frontiers of Medicine in China 4(2):177-184.

Publication Stats

9 Citations
6.08 Total Impact Points

Institutions

  • 2010–2013
    • Institute of Plant Protection, Chinese Academy of Agricultural Sciences
      Peping, Beijing, China
    • Sichuan Agricultural University
      Hua-yang, Sichuan, China
  • 2006–2012
    • Capital Medical University
      Peping, Beijing, China