Guang Yang

Hangzhou First People's Hospital, Hang-hsien, Zhejiang Sheng, China

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Publications (6)3.73 Total impact

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    ABSTRACT: Liver fibrosis is a major cause of liver failure, but treatment remains ineffective. In the present study, we investigated the mechanisms and anti-hepatofibrotic activities of asiatic acid (AA) in a rat model of liver fibrosis induced by carbon tetrachloride (CCl(4)) and in vitro in TGF-beta1-stimulated rat hepatic stellate cell line (HSC-T6). Treatment with AA significantly attenuated CCl(4)-induced liver fibrosis and functional impairment in a dosage-dependent manner, including blockade of the activation of HSC as determined by inhibiting de novo alpha smooth muscle actin (a-SMA) and collagen matrix expression, and an increase in ALT and AST (all p<0.01). The hepatoprotective effects of AA on fibrosis were associated with upregulation of hepatic Smad7, an inhibitor of TGF-beta signaling, thereby blocking upregulation of TGF-beta1 and CTGF and the activation of TGF-beta/Smad signaling. The anti-fibrosis activity and mechanisms of AA were further detected in vitro in HSC-T6. Addition of AA significantly induced Smad7 expression by HSC-T6 cells, thereby inhibiting TGF-beta1-induced Smad2/3 activation, myofibroblast transformation, and collagen matrix expression in a dosage-dependent manner. In contrast, knockdown of Smad7 in HSC-T6 cells prevented AA-induced inhibition of HSC-T6 cell activation and fibrosis in response to TGF-beta1, revealing an essential role for Smad7 in AA-induced anti-fibrotic activities during liver fibrosis in vivo and in vitro. In conclusion, AA may be a novel therapeutic agent for liver fibrosis. Induction of Smad7-dependent inhibition of TGF-beta/Smad-mediated fibrogenesis may be a central mechanism by which AA protects liver from injury.
    PLoS ONE 01/2012; 7(2):e31350. · 3.73 Impact Factor
  • Li-xia Tang, Guang Yang, Jia-ju Tang
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    ABSTRACT: To investigate the effect of Smad7 on the expressions of collagen I and alpha-smooth muscle actin (alpha-SMA) in HSC-T6 cell line activated by transforming growth factor-beta1 (TGF-beta1). HSC-T6 cells stably expressing M2-flag protein were selected after co-infection of the cells with pTRE-Smad7-M2-flag and pTet-on. The optimal dose of doxycycline for inducing Smad7 was determined, and the effects of Smad7 over-expression on the expressions of collagen I and alpha-SMA in the cells activated by TGF-beta1 and on Smad2/3 phosphorylation were evaluated using Western blotting. The optimal dose of doxycycline for inducing Smad7 expression was 2 mg/L. Smad7 over-expression induced by doxycycline decreased the expressions of collagen I and alpha-SMA in HSC-T6 cells activated by TGF-beta1, and down-regulated the level of Smad2/3 phosphorylation. Smad7 over-expression inhibits Smad2/3 phosphorylation, and decreases the expression of collagen I and alpha-SMA in HSC-T6 cells induced by TGF-beta1 to inhibit the progression of liver fibrosis.
    Nan fang yi ke da xue xue bao = Journal of Southern Medical University 10/2009; 29(10):2122-3, 2127.
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    ABSTRACT: To identify patients with SARS coronavirus infection who have only mild symptoms. Enzyme-linked immunosorbent assay was employed to detect serum antibody against SARS coronavirus in the lysate of whole SARS coronavirus from 19 SARS patients and 200 medical staff members without obvious SARS symptoms after possible exposure to the virus during routine medical practice. Serum IgG antibody against SARS coronavirus was detected in all the 19 SARS patients, and among the 200 staff members, 20 (10%) were found positive for the antibody but with no obvious or only mild symptoms. Serum IgG antibody against SARS coronavirus is positive in a small proportion (around 10%) of the medical staff members exposed to the virus in our hospital, but may not cause obvious symptoms, suggesting SARS coronavirus infection might in some cases have mild or even no clinical manifestations.
    Nan fang yi ke da xue xue bao = Journal of Southern Medical University 03/2006; 26(2):220-1.
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    ABSTRACT: To develop a new platform for genotyping human papillomavirus (HPV) and to investigate its effect in clinical application. A pair of common primers of 18 HPV subtypes for PCR, was designed in HPV conservative L1 region. Genotyping probes for detecting 15 high-risk HPV subtypes 16, 18, 31, 33, 35, 39, 45, 51, 52, 53, 56, 58, 59, 66 and 68, together with 3 low-risk HPV 6, 11 and 42 were selected respectively from Genbank and fixed on membrane to make DNA chip. PCR amplification and DNA chip technology were optimized. 100 clinical samples were used to investigate the effect of HPV genotyping DNA chip. Veracity of the genotyping results was verified by sequencing. From the 100 clinical samples, 30 were found to be HPV positive, including high-risk HPV subtypes 16, 18, 33, 45, 51, 58, and 66, and low-risk HPV 6, 11 and 42. The sensitivity tested by standard samples was up to 10 copies of HPV DNA. The HPV genotyping system developed here with DNA chip showed high sensitivity and specificity, suitable to be applied in clinical practice for HPV diagnosis and investigation on the prevalence of HPV sub-types.
    Zhonghua liu xing bing xue za zhi = Zhonghua liuxingbingxue zazhi 02/2006; 27(1):47-9.
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    ABSTRACT: Using polymerase chain reaction-reverse blot dot (PCR-RDB) technique to establish a new method for hepatitis C virus (HCV) genotyping and to study the distribution of HCV genotypes in Foshan area. HCV primers and probes were designed in 5'-untranslated region (nt-1-nt-299) of HCV. HCV RNA in serum was isolated and purified, and its cDNA was obtained by reversed transcription. Nested PCR using biotin-labelled primers, was done. PCR products were hybridized with immobilized specific probes (genotype 1a to 3b) on Biodyne C membrane to genotype HCV by color development while adding POD and TMB. A certain judgment could be made according to the position of color reaction. The reliability of this new method was verified by sequencing. HCV RNA levels in serum were determined by real time fluorescent quantitative (FQ)-PCR. 60 FQ-PCR-positive HCV sera from Foshan area were genotyped using this assay. All 60 sera could be successfully genotyped by PCR-RBD. 50 (83.3%) cases were found to be genotype 1b, 2 (3.3%) as genotype 1a and 2 (3.3%) as genotype 2a while 5 (8.0%) to be mixture of genotype 1a and 1b, and 1 (1.7%) to be mixture of genotypes 1b and 2a. No genotypes 2b, 3a and 3b were found. The results of PCR-RDB genotyping methods coincided with sequence analysis. Newly established HCV genotyping system was proved to be sensitive, specific, precise and economic, thus suitable for clinical and epidemiologic studies. The results of HCV genotyping showed that genotype 1b was the predominant genotype in Foshan area.
    Zhonghua liu xing bing xue za zhi = Zhonghua liuxingbingxue zazhi 07/2005; 26(6):440-3.
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    ABSTRACT: Using PCR-RDB to establish a new method for HBV genotyping, and to survey the distribution of HBV genotypes in the Foshan area. Biotin-labeled primers for amplification of HBV region X (nt1550-1789) were used to amplify extracted HBV DNA. HBV was genotyped by hybridization of the PCR products with immobilized specific probes (genotype A to F) on C membrane. Color development was achieved by adding POD and TMB. A judgment was made according to color reactions. The reliability of this new method was verified by gene sequencing. 300 samples of HBV DNA-positive sera from the Foshan area were genotyped using this assay. Of the 300 sera genotyped by PCR-RBD, 147 (49.0%) cases were genotype B, 136 (45.3%) were genotype C, 1 (0.3%) genotype D, and 12 (4.0%) were mixtures of genotype B and C, and 4 (1.3%) were mixtures of genotype C and D. No genotype A, E or F were found. The results of PCR-RDB genotyping were consistent with the results obtained with sequence analysis. This newly established HBV genotyping system proved to be sensitive, specific, precise and economic, and should be suitable for clinical practice and epidemic study. The results of HBV genotyping show that genotype B and C are the predominant genotypes in the Foshan area.
    Zhonghua gan zang bing za zhi = Zhonghua ganzangbing zazhi = Chinese journal of hepatology 12/2004; 12(11):677-80.