Biomedical subjects

Wen-Sheng Chen

Publications and source records attributed to Wen-Sheng Chen.

5 recordsLinked to original sources

PubMed2006

A comparison of gene expression in mouse liver and kidney in obstructive cholestasis utilizing high-density oligonucleotide microarray technology.

AIM: To assess the effects of obstructive cholestasis on a wider range of gene expression using microarray technology. METHODS: Male C57BL/6J mice underwent common bile duct ligation (BDL) and were matched with pair-fed sham-operated controls. After 7 d, the animals were sacrificed and total RNA was isolated from livers and kidneys. Equal amounts of RNA from each tissue were pooled for each group and hybridized to Affymetrix GeneChip MG-U74Av2 containing a total of 12488 probe sets. Data analysis was performed using GeneSpring 6.0 software. Northern analysis and immunofluorescence were used for validation. RESULTS: In sham-operated and BDL mice, 44 and 50% of 12488 genes were expressed in livers, whereas 49 and 51% were expressed in kidneys, respectively. Seven days after BDL, 265 liver and 112 kidney genes with GeneOntology annotation were up-regulated and 113 liver and 36 kidney genes were down-regulated in comparison with sham-operated controls. Many genes were commonly regulated in both tissues and metabolism-related genes represented the largest functional group. CONCLUSION: Following BDL, microarray analysis reveals a broad range of gene alterations in both liver and kidney.

25-Hydroxyvitamin D3 1-alpha-Hydroxylase↗

PubMed2005

Kernel machine-based one-parameter regularized fisher discriminant method for face recognition.

This paper addresses two problems in linear discriminant analysis (LDA) of face recognition. The first one is the problem of recognition of human faces under pose and illumination variations. It is well known that the distribution of face images with different pose, illumination, and face expression is complex and nonlinear. The traditional linear methods, such as LDA, will not give a satisfactory performance. The second problem is the small sample size (S3) problem. This problem occurs when the number of training samples is smaller than the dimensionality of feature vector. In turn, the within-class scatter matrix will become singular. To overcome these limitations, this paper proposes a new kernel machine-based one-parameter regularized Fisher discriminant (K1PRFD) technique. K1PRFD is developed based on our previously developed one-parameter regularized discriminant analysis method and the well-known kernel approach. Therefore, K1PRFD consists of two parameters, namely the regularization parameter and kernel parameter. This paper further proposes a new method to determine the optimal kernel parameter in RBF kernel and regularized parameter in within-class scatter matrix simultaneously based on the conjugate gradient method. Three databases, namely FERET, Yale Group B, and CMU PIE, are selected for evaluation. The results are encouraging. Comparing with the existing LDA-based methods, the proposed method gives superior results.

Algorithms↗

PubMed2004

Multidrug resistance-associated protein 4 is up-regulated in liver but down-regulated in kidney in obstructive cholestasis in the rat.

BACKGROUND/AIMS: Multidrug resistance-associated protein 4 (Mrp4, ABCC4) transports cyclic nucleotides, anti-retroviral compounds, and sulfated bile acids. Mrp4 expression is increased in farnesyl/bile acid receptor knockout mice. Our aim was to investigate Mrp4 expression and function in rat liver and kidney in obstructive cholestasis. METHODS: Male Sprague-Dawley rats were subjected to bile duct ligation (BDL) or sham-surgery. Animals were sacrificed after 3, 7, and 14 days and tissues were harvested for Western blot analysis, real-time reverse transcriptase-mediated polymerase chain reaction (RT-PCR), and immunohistochemistry. RESULTS: Western blot analysis revealed a progressive, more than seven-fold increase (P < 0.05) of Mrp4 expression in cholestatic livers, 14 days after BDL. In contrast, Mrp4 in 14-day BDL kidneys decreased to 26+/-4% of controls (P < 0.005). Immunohistochemistry localized Mrp4 to the basolateral hepatocyte membrane and corroborated its hepatic up-regulation after BDL. Real-time RT-PCR demonstrated no major changes of Mrp4 mRNA levels in liver and kidney after BDL. Cyclic adenosine monophosphate, an MRP4 substrate, was increased in plasma and urine, consistent with these findings. CONCLUSIONS: Obstructive cholestasis in rats results in progressive up-regulation of Mrp4 protein in liver but down-regulation in kidney. The absence of corresponding changes in Mrp4 mRNA suggests posttranscriptional mechanisms as predominant regulators of Mrp4 expression in BDL rats.

Animals↗

PubMed2003

Tumor necrosis factor alpha-dependent up-regulation of Lrh-1 and Mrp3(Abcc3) reduces liver injury in obstructive cholestasis.

Mrp3(Abcc3) is markedly induced following bile duct ligation (BDL) in the rat and in some human cholestatic liver diseases and is believed to ameliorate liver injury in this setting. Recently, the orphan nuclear receptor fetoprotein transcription factor/cholesterol-7alpha-hydroxylase promoter factor (CPF/FTF/Lrh-1) has been shown to activate Mrp3 expression. However, whether inflammatory cytokines or elevated bile acid levels increased Lrh-1/Mrp3 expression in obstructive cholestasis was not known. We hypothesized that induction of Mrp3 would be associated with Lrh-1 up-regulation and would require intact cytokine signaling. Male tumor necrosis factor (Tnf) receptor I (Tnfr-/-) mice and C57BLJ wild type (WT) controls were subjected to sham surgery or bile duct ligation. HepG2 cells were treated with bile acids or cytokines. Immunoblot assay and real time reverse transcriptase-PCR were used to determine expression of MRP3/Mrp3, CPF/Lrh-1, Mrp2, and Bsep. CPF/Lrh-1 DNA binding to the MRP3/Mrp3 promoter was assessed using electrophoretic mobility shift assay, and promoter activity was determined by luciferase assay. Total bile acids and lactate dehydrogenase were measured using colorimetric assays, and cytokine abundance was determined by enzyme-linked immunosorbent assay. Lrh-1 and Mrp3 were significantly induced after BDL in WT but not Tnfr-/- mice. This was associated with more severe hepatocellular necrosis in Tnfr-/- mice. Lrh-1 binding to the Mrp3 promoter increased after BDL in WT but not in Tnfr-/- mice. Tnfalpha treatment of HepG2 cells also up-regulated CPF and MRP3, increased CPF binding to the MRP3 promoter, and up-regulated MRP3 promoter activity. These results indicate that induction of Mrp3 after BDL is due to Tnfalpha-dependent up-regulation of Lrh-1. They provide strong evidence that induction of Mrp3 plays a significant role in hepatocyte protection during obstructive cholestasis.

Animals↗

PubMed2003

Effects of insulin-like growth factors-IR and -IIR antisense gene transfection on the biological behaviors of SMMC-7721 human hepatoma cells.

BACKGROUND AND AIMS: Insulin-like growth factors (IGFs) are closely related to hepatocellular carcinoma growth. The study aim was to investigate the effects of IGF-IR and IGF-IIR antisense gene transfection on the biological behaviors of SMMC-7721 human hepatoma cells. METHODS: 7721-IGF-IR-AS cells (human hepatoma SMMC-7721 cells transfected with IGF-IR antisense gene in our previous study) were transfected with a plasmid vector expressing IGF-IIR cDNA in the antisense orientation by DOTAP liposome.7721-IGF-R-AS cells were obtained by selection with G418 and hygromycin. Morphological changes of the cells were observed with optic and electron microscopes. In vitro growth of the 7721-IGF-R-AS cells was observed with a soft agar test, MTT test and with naked mice inoculation test in vivo. RESULTS: The following changes were found in the SMMC-7721 cells after being transfected with the IGF-IR and IGF-IIR antisense genes: (i) the degree of malignancy of the tumor cells as revealed by cell morphology was ameliorated; (ii) the growth capability of the tumor cells in soft agar and their tumorigenicity in naked mice were significantly depressed. However, in the control groups, the SMMC-7721 cells transfected both with IGF-IR and IGF-IIR sense cDNA and SMMC-7721 cells transfected without any external genes, had no such changes. However, the cell growth curves had no significant differences among these three groups. CONCLUSION: IGF-IR and IGF-IIR antisense genes could significantly restrain the malignant behavior of human hepatoma cells and might be useful in investigating a potential route for hepatocellular carcinoma gene therapy.

Animals↗