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Li Y, Huang T, Tang H, Yamamura K, Pu X. Gene expression profiling: identification of genes with altered expression in Ayu17-449 knockout mice. GENETICS AND MOLECULAR RESEARCH 2011; 10:1533-44. [DOI: 10.4238/vol10-3gmr1158] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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277
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Tang H. The current situation and prospect of acupuncture for essential hypertension. Eur J Integr Med 2010. [DOI: 10.1016/j.eujim.2010.09.141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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278
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Lin J, Lin L, Tang H, Xu C. e0158 Transient prehypertensive treatment in spontaneously hypertensive rats: a comparison of losartan and amlodipine regarding long-term blood pressure and cardiac protection. BRITISH HEART JOURNAL 2010. [DOI: 10.1136/hrt.2010.208967.158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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279
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Lin J, Tang H, Lin L, Xu C. e0160 Transient prehypertensive treatment in spontaneously hypertensive rats:a comparison of losartan and amlodipine regarding long-term blood pressure and renal protective effect. BRITISH HEART JOURNAL 2010. [DOI: 10.1136/hrt.2010.208967.160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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280
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Li X, Li Y, Zheng D, Tang H, Wen M. e0219 Study on the Role of CD4+CD25+treg on Atherosclerosis in ApoE-/- Mice. BRITISH HEART JOURNAL 2010. [DOI: 10.1136/hrt.2010.208967.219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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281
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Tang H, Wu J, Yang Q, Ma Z. e0442 Effect of aspirin and cilostazol on inflammatory cytokines in patients with acute coronary syndrome. BRITISH HEART JOURNAL 2010. [DOI: 10.1136/hrt.2010.208967.442] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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282
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Xiao CH, Tang H, Pu LJ, Sun DM, Ma JZ, Yu M, Duan RS. Diversity of nitrogenase (nifH) genes pool in soybean field soil after continuous and rotational cropping. J Basic Microbiol 2010; 50:373-9. [PMID: 20473958 DOI: 10.1002/jobm.200900317] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Diazotrophs diversity in soybean is a topic requiring thorough investigation since the previous researches have focused on only rice, forest, grass, water, etc. In this research, iron-only nitrogenase nifH gene was as genetic marker. PCR-RFLP was used to investigate the difference of diazotrophs community diversity in the soil from the continuous cropping (CC) (the 5-yr tilling of soybean) and the rotational cropping (RC) (soybean-corn) soils in the northeast of China. A total of 36 isolates were genetically characterized. Most of the isolates closely related to Azospirillum and Azotobacter. Eighty-six unique nifH gene sequences were obtained by cloning of the respective PCR products in two soil samples. It was found that the diversity of nifH genes in CC changed obviously compared with RC. Phylogenetic analysis indicated that most of the clones clustered together in a high homogeneity with some sequence retrieved from environmental representatives. The sequence diversity of nifH genes was high and the members of the Alphaproteobacteria were predominant in both samples. The experimental study also revealed the two non-proteobacterial diazotrophs, firmicutes and euryarchaeota. Through this study, it can be assumed that different tillage perhaps affected the nifH gene-containing population diversity.
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Zhu H, Chen H, Zhong Y, Ren D, Qian Y, Tang H, Zhu Y. Determination of Trace Inorganic Anions in Weak Acids by Single-Pump Column-Switching Ion Chromatography. J Chromatogr Sci 2010; 48:553-8. [DOI: 10.1093/chromsci/48.7.553] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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284
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Chen EQ, Zhou TY, Tang H. PL-009 Combination of telbivudine and adefovir dipivoxil therapy in chronic hepatitis B patients with poor response to adefovir dipivoxil monotherapy. Int J Infect Dis 2010. [DOI: 10.1016/s1201-9712(10)60051-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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285
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Tang H, Fang Z, Sun Y, Li B, Shi Z, Chen J, Zhang T, Xiu Q. YKL-40 in asthmatic patients, and its correlations with exacerbation, eosinophils and immunoglobulin E. Eur Respir J 2010; 35:757-60. [PMID: 20356987 DOI: 10.1183/09031936.00034409] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The chitinase-like protein YKL-40, which binds chitin but lacks chitinase activity, has been found to be either the cause or a biomarker for asthma. The aim of our study was to investigate whether serum YKL-40 levels are increased in Chinese patients with asthma and identify its correlation to acute exacerbation, total serum immunoglobulin (Ig)E, the percentage of peripheral blood eosinophils and lung function. We quantified serum YKL-40 levels, total IgE levels and peripheral blood eosinophil percentages in patients with asthma, as well as in controls from the communities surrounding our hospital. The lung function of asthma subjects was also measured. Our data showed that the serum YKL-40 levels were significantly elevated in patients with asthma compared with controls and, when the asthma subjects were stratified, serum YKL-40 levels in the exacerbation group were higher than those in the stable and control groups. In addition, serum YKL-40 levels correlated positively with total serum IgE levels and the percentage of peripheral blood eosinophils, but correlated inversely with lung functions. Thus, we conclude that YKL-40 is found in increased quantities in the serum of Chinese patients with asthma, and its level correlates with exacerbation attacks, indicating that high levels of serum YKL-40 may be a biological characteristic of the exacerbation of asthma.
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286
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Huang TJ, Li D, Weatherly J, Tang H, Gout PW, Wolff RA, Abbruzzese JL, Javle MM. Prognostic significance of xCT gene single nucleotide polymorphisms (SNPs) in patients (pts) with advanced pancreatic cancer (PC) treated with gemcitabine (GEM) plus platinum analogues (PLAT). J Clin Oncol 2010. [DOI: 10.1200/jco.2010.28.15_suppl.4065] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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287
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Kotanko P, Schiller B, Zeig S, Pergola P, Whittier F, Zabaneh R, Besarab A, Kaplan M, Covic A, Macdougall I, Duliege A, Tang H, Levin N. 163: EPO and Hematide™ Requirements Differ in ESA Hyporesponsive HD Patients. Am J Kidney Dis 2010. [DOI: 10.1053/j.ajkd.2010.02.170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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288
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Wang LC, Chen EQ, Cao J, Liu L, Wang JR, Lei BJ, Tang H. Combination of Lamivudine and adefovir therapy in HBeAg-positive chronic hepatitis B patients with poor response to adefovir monotherapy. J Viral Hepat 2010; 17:178-84. [PMID: 19656287 DOI: 10.1111/j.1365-2893.2009.01164.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
At present, there is no consensus treatment for patients who have poor response to Adevofir dipivoxil (ADV) monotherapy and no ADV-associated mutation. The purpose of this study was to evaluate the effect of a new therapeutic strategy combining Lamivudine (LAM) and ADV in patients with HBeAg-positive chronic hepatitis B (CHB) and poor response to ADV monotherapy. Thirty-one patients with chronic hepatitis B with HBV DNA > or = 10(4) copies/mL after 48 weeks of ADV monotherapy were included and received ADV plus LAM for 24 weeks. Compared with ADV monotherapy, ADV + LAM had an improved response rate at weeks 12 and 24 - compared with baseline, the median decrease in HBV-DNA level at week 12 and 24 were 1.27 and 2.03 log respectively. The virological response (VR) rate (HBV-DNA level <10(3) copies/mL) was 6.5% and 35.5% at weeks 12 and 24, respectively; the biochemical response (BR) rate (normalization of alanine aminotransferase levels) was 67.8% and 100%, respectively; the HBeAg loss rate was 6.9% and 34.5%, respectively; and the seroconversion rate (from HBeAg to HBeAb) was 3.5% and 6.9% respectively. No ADV-associated mutation was detected at baseline. After combination therapy for 24 weeks, no LAM-resistant or ADV-resistant mutations were detected. Only one patient had a mild adverse reaction. In conclusion, optimization of therapy combining LAM and ADV may be a good choice for patients with hepatitis B who have a poor response to ADV monotherapy.
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Qian Y, Meng J, Tang H, Yang G, Deng Y, Wei D, Xiang B, Xiao X. Different structural remodelling in atrial fibrillation with different types of mitral valvular diseases. Europace 2010; 12:371-7. [DOI: 10.1093/europace/eup438] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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290
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Tang H, Schlapbach C, Hassan AS, Simon D, Yawalkar N. Characterization of dendritic cells and macrophages in irritant contact dermatitis. J Dermatol Sci 2010; 57:216-8. [PMID: 20138475 DOI: 10.1016/j.jdermsci.2010.01.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2009] [Revised: 12/22/2009] [Accepted: 01/06/2010] [Indexed: 11/30/2022]
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291
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Chudzinski RE, Khwaja K, Teune P, Miller J, Tang H, Pavlakis M, Rogers C, Johnson S, Karp S, Hanto D, Mandelbrot D. Successful DCD kidney transplantation using early corticosteroid withdrawal. Am J Transplant 2010; 10:115-23. [PMID: 19958332 DOI: 10.1111/j.1600-6143.2009.02922.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Organs from donors after cardiac death (DCD) are being increasingly utilized. Prior reports of DCD kidney transplantation involve the use of prednisone-based immunosuppression. We report our experience with early corticosteroid withdrawal (ECSW). Data on 63 DCD kidney transplants performed between 2002 and 2007 were analyzed. We compared outcomes in 28 recipients maintained on long-term corticosteroids (LTCSs) with 35 recipients that underwent ECSW. DGF occurred in 49% of patients on ECSW and 46% on LTCS (p=0.8). There was no difference between groups for serum creatinine or estimated GFR between 1 and 36 months posttransplant. Acute rejection rates at 1 year were 11.4% and 21.4% for the ECSW and LTCS group (p=0.2). Graft survival at 1 and 3 years was 94% and 91% for the ECSW group versus 82% and 78% for the LTCS group (p>or=0.1). Death censored graft survival was significantly better at last follow-up for the ECSW group (p=0.02). Multivariate analysis revealed no correlation between the use of corticosteroids and survival outcomes. In conclusion, ECSW can be used successfully in DCD kidney transplantation with no worse outcomes in DGF, rejection, graft loss or the combined outcome of death and graft loss compared to patients receiving LTCS.
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292
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Li S, Luo C, Yu B, Yan B, Gong Q, He C, He L, Huang X, Yao D, Lui S, Tang H, Chen Q, Zeng Y, Zhou D. Functional magnetic resonance imaging study on dysphagia after unilateral hemispheric stroke: a preliminary study. J Neurol Neurosurg Psychiatry 2009; 80:1320-9. [PMID: 19515639 DOI: 10.1136/jnnp.2009.176214] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND Swallowing dysfunction is common and disabling after acute stroke; however, the mechanism of dysphagia or recovery of swallowing from dysphagia remains uncertain. The purpose of this study was to explore cerebral activation of swallowing in dysphagia using functional MRI (fMRI) to compare the functional anatomy of swallowing in unilateral hemispheric stroke patients and healthy adults. METHODS In total, five left hemispheric stroke patients with dysphagia, five right hemispheric stroke patients with dysphagia and 10 healthy controls were examined with event related fMRI while laryngeal swallow related movements were recorded. Data were processed using the general linear model. RESULTS A multifocal cerebral representation of swallowing was identified predominantly in the left hemisphere, in a bilateral and asymmetrical manner. Cerebral activation during swallowing tasks was localised to the precentral, postcentral and anterior cingulate gyri, insula and thalamus in all groups. Activation of volitional swallowing in dysphagic unilateral hemispheric stroke patients might require reorganisation of the dominant hemispheric motor cortex, or a compensatory shift in activation to unaffected areas of the hemisphere. CONCLUSIONS The results indicate that unilateral stroke of either cerebral hemisphere can produce dysphagia. Effective recovery is associated with cerebral activation related to cortical swallowing representation in the compensating or recruited areas of the intact hemisphere. Functional MRI is a useful method for exploring the spatial localisation of changes in neuronal activity during tasks that may be related to recovery. Therefore, the subsequent information gleaned from changes in neural plasticity could be useful for assessing the prognosis of dysphagic stroke.
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293
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Lei W, Sun M, Luo KM, Shui XR, Sun YM, Tang H. [Compute simulation to characterize structure and function of chalcone synthase from Scutellaria baicalensis Georgi]. Mol Biol (Mosk) 2009; 43:1082-1087. [PMID: 20088386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Prediction and analysis of molecular structure and biochemical function are of theoretical guiding significance for gene discovery and application, and considered as one of the central problem of computational biology. Here, some characteristic features of chalcone synthase (CHS) family from Scutellaria baicalensis were described via bioinformatic analysis, and showed as following: the nucleic acid sequences and amino acid sequences of three chs member genesshared high similarity inthe molecular structures and physicochemical properties; SbCHS proteins were localized to the cytosol, and possessed a good hydrophobic nature, with lacking any transmembrane topological structure. The phylogram analysis suggested that they were a group genes with significant functional association and genetic conservation. The secondary structures of the SbCHSs were mainly composed of alpha-helixes and random coils, and the tertiary structures contained malonyl CoA linkers, besides, each of CHS-A and CHS-B with N-glycosylation motif included. Taken together, these results demonstrate that CHS family from S. baicalensis has the typical molecular structure and function of chalcone synthase, compared with the experimental data for Medicago sativa CHS protein.
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294
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Tang H, Gong YZ, Wu CX, Jiang J, Wang Y, Li K. Variation of meat quality traits among five genotypes of chicken. Poult Sci 2009; 88:2212-8. [PMID: 19762878 DOI: 10.3382/ps.2008-00036] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The main objective of this study was to examine the diversity of meat quality traits among 5 chicken genotypes. The genotypes included 2 Chinese native breeds (Wenchang,WCH, and Xianju), 1 commercial broiler line (Avian, AV), 1 commercial layer line (Hy-Line Brown, HLB), and 1 Chinese commercial broiler line (Lingnanhuang, LNH) synthesized by exotic and native breeds, which were slaughtered at their market ages: 16, 7, 16, and 8 wk, respectively. The effects of genotype, muscle type, and sex on meat quality traits were examined. Birds from slow-growing genotypes (WCH, Xianju, and HLB) exhibited higher shear value, inosine-5'-monophosphate concentration, lower cook loss, and more fat than those from fast-growing genotypes (AV and LNH). Chickens from WCH possessed the lowest expressible moisture, cook loss, and the highest lipid (%) among the 3 slow-growing genotypes. The HLB birds were intermediate in expressible moisture and cook loss and lowest in lipid among all genotypes. The LNH cross birds were similar to AV broilers in most meat quality parameters, although they had a lower shear force value and higher fat content than AV broilers. Breast muscle had higher expressible moisture, shear force, protein (%), inosine-5'-monophosphate content, lower cook loss, and lipid (%) than leg muscle. Muscles from male chickens had higher expressible moisture than those from the females. Variability of meat quality characteristics is mainly related to genotype and muscle type differences.
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295
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Zhu S, Chen J, Li Y, Tang H, Huang X. MP-18.03: Comparative Study of Intermittent Versus Continuous Androgen Blockade in the Treatment of Advanced Prostate Cancer. Urology 2009. [DOI: 10.1016/j.urology.2009.07.1338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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296
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Gnanakaran G, Bhattacharya T, Daniels M, Lapedes A, Gao F, Kumar A, Li M, Tang H, Greene K, Gao H, Seaman M, Haynes BF, Montefiori DC, Korber BT. P04-54 LB. Genetic signature analysis identifies the CD4i region of gp120 as a determinant of broadly NAb responses in HIV-1-infected individuals. Retrovirology 2009. [PMCID: PMC2767908 DOI: 10.1186/1742-4690-6-s3-p394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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297
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Viola H, Macdonald W, Tang H, Hool L. The L-Type Ca2+ Channel as a Therapeutic Target in Heart Disease. Curr Med Chem 2009; 16:3341-58. [DOI: 10.2174/092986709789057671] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2009] [Accepted: 06/18/2009] [Indexed: 11/22/2022]
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298
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Long Y, Chen E, Liu C, Huang F, Zhou T, He F, Liu L, Liu F, Tang H. The correlation of hepatocyte nuclear factor 4 alpha and 3 beta with hepatitis B virus replication in the liver of chronic hepatitis B patients. J Viral Hepat 2009; 16:537-46. [PMID: 19302415 DOI: 10.1111/j.1365-2893.2009.01089.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Hepatocyte nuclear factors 4 alpha (HNF4alpha) and 3 beta (HNF3beta) are members of a group of liver-enriched transcription factors (LETFs) that play important roles in regulating the replication of hepatitis B virus (HBV). Using cell culture and animal models, we showed that HNF4alpha supports HBV replication in nonhepatic cells and HNF3beta inhibits HBV replication. However, the expression of HNF4alpha and HNF3beta in the liver tissue of chronic HBV-infected patients and the relationship between the levels of HNF4alpha and HNF3beta and HBV replication are unclear. In this study, liver biopsy specimens from 86 chronic HBV-infected patients were collected. The expression levels of HNF4alpha, HNF3beta, hepatitis B surface antigen (HBsAg) and hepatitis B core antigen (HBcAg) were detected by an immunohistochemical technique and the level of HBV DNA was checked by in situ hybridization with serial sections from liver biopsy tissue samples. We show here that samples with higher levels of HNF4alpha expression also have higher levels of HBsAg, HBcAg and HBV DNA. In contrast, in samples with higher levels of HNF3beta expression, levels of HBsAg, HBcAg and HBV DNA were lower. There was a positive correlation between HNF4alpha expression and HBV replication, and a negative correlation between HNF3beta expression and HBV replication, in the liver of chronic HBV-infected patients. This suggests that HNF4alpha and HNF3beta likely participate in HBV replication in patients with HBV infection, or that HBV replication may somehow influence the expression of HNF4alpha and HNF3beta in the liver.
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Wang C, Liu X, Ye Z, Zhang J, Tang H, Chen Z, Zhang H, Lou T. Mesangial medium with IgA1 from IgA nephropathy inhibits nephrin expression in mouse podocytes. Eur J Clin Invest 2009; 39:561-7. [PMID: 19397686 DOI: 10.1111/j.1365-2362.2009.02135.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND IgA nephropathy (IgAN) is characterized by mesangial deposition of polymeric IgA1, and podocyte injury plays an important role in glomerulosclerosis of the disease. Our previous study indicated that medium of mesangial cells co-incubated with aggregated IgA1 (aIgA1), isolated from IgAN patients, down-regulated nephrin expression. Yet the mechanism remains unclear. MATERIALS AND METHODS Podocytes were incubated with a medium of mesangial cells co-incubated with aIgA1, which was isolated from IgAN patients, and enalaprilat (10(-5) M), valsartan (10(-5) M) and anti-mouse tumour necrosis factor-alpha antibody (50 ng mL(-1)) separately. Nephrin expression in podocytes was measured by real-time polymerase chain reaction and Western blot analysis. RESULTS The level of angiotensinogen and angiotensin-converting enzyme mRNAs in podocytes, as well as angiotensin, was also increased by a medium of mesangial cells co-incubated with aIgA1 from IgAN patients (P<0.05). Enalaprilat or valsartan partly improved nephrin expression when compared with that by podocytes exposed to the mesangial medium (P<0.05), while the nephrin expression of podocytes with enalaprilat or valsartan was lower than that of podocytes exposed to medium of mesangial cells stimulated by aIgA1 from healthy control (P<0.05). However, anti-mouse tumour necrosis factor-alpha antibody did not show any improvement in nephrin expression. CONCLUSION Our findings implicate that local renin angiotensin system activation in podocytes is partly involved in down-regulation of nephrin by mesangial medium in IgA nephropathy.
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Tang H, Foster NR, Grothey A, Ansell SM, Sargent DJ. Excessive false-positive errors in single-arm phase II trials: A simulation-based analysis. J Clin Oncol 2009. [DOI: 10.1200/jco.2009.27.15_suppl.6512] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
6512 Background: The use of randomized phase II designs with an experimental arm and a standard-treatment control arm (R2PII) instead of a conventional single-arm design is clearly increasing in oncology. In practice, sample size, related cost issues, the belief that historical controls are adequate, and the use of a standard-treatment control arm in a phase II setting are frequently raised objections to R2PII trials. As the expense and complexity of definitive phase III trials increase, the ability of phase II trials to provide reliable and accurate results is critical. Methods: We investigated the ability of single arm vs R2PII trials to provide accurate conclusions by modeling variability in historical controls, patient outcome drifts independent of the tested therapy, and patient selection effects. Simulations compared R2PII and single-arm designs with binary endpoints under realistic parameters (e.g. alpha = beta = 0.10, historical control success rate = 20%, target success rate = 40%). Results: In the absence of variability in historical controls, estimated false positive and negative rates in both designs mirror the designated specifications. However, even in the presence of a modest drift effect in the population (mean 5% absolute shift in true control success rate), the false positive rate in single-arm designs is inflated two to three fold (to 20%-30%), while the R2PII retains the desired error rates. Greater confidence in historical controls in the single-arm design corrects only a small portion of the deviations. Increasing the sample size in each trial inflates the false positive error rate further to as much as 50%. Varying several sets of parameters gave similar results. Conclusions: In the presence of variability in historical controls, patient drift and/or selection effects, the false positive error rate of a single arm design is unacceptably high. In contrast, the R2PII design is reliable and robust despite the complexities in patient outcome drift and selection effects, and variability in historical control success rates. Given the rapid improvements in outcomes of many tumor types, the R2PII design should be the preferred method to evaluate novel agents in oncology in spite of the associated costs and the use of a reference control arm. No significant financial relationships to disclose.
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