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Biomedical subjects

Wei-Jen Chen

Publications and source records attributed to Wei-Jen Chen.

At least 19 recordsLinked to original sources
PubMed2006

Hepatitis C virus genotypes in southern Taiwan: prevalence and clinical implications.

The role of hepatitis C virus (HCV) genotypes in the development of hepatocellular carcinoma (HCC) is still controversial. To determine the distribution and clinical implications of HCV genotypes in southern Taiwan, we analysed 418 patients with chronic HCV infections. HCV genotypes were determined using an HCV Line Probe Assay. The predominant HCV genotype was 1b (45.5%), followed by 2a/2c (30.9%) and 2b (6.9%). The prevalence of genotype 1b in HCC patients (60.3%) was significantly higher than in those with liver cirrhosis (38.7%) and chronic hepatitis (38.7%) (P=0.003 and P<0.001, respectively). Patients with chronic HCV 2a/2c infection had higher alanine aminotransferase (ALT) levels than those with chronic HCV 1b infection (P<0.001). Univariate analysis revealed that disease severity was significantly correlated with older age, genotype 1b, lower ALT levels and lower viral load. Based on multiple logistic regression analysis, after adjusting for age and serum HCV RNA levels, HCV 1b infection was still a significant risk factor for HCC. In conclusion, the predominant genotypes in southern Taiwan were 1b and 2a/2c, and disease severity was associated with genotype 1b.

Aged↗
PubMed2006

Foreign body granuloma caused by monosodium glutamate after BCG vaccination.

We describe a 7-month-old male infant with a foreign body granuloma caused by monosodium glutamate (MSG) after a Bacille Calmette-Guérin (BCG) immunization. A ridged, erythematous, indurated plaque developed over a BCG injection site on his left upper arm 1 month after the first BCG immunization. Biopsy showed multiple noncaseating foreign body granulomas without detectable mycobacteria by both Ziehl-Neelsen stain and polymerase chain reaction assay. Birefringent crystals were identified in the foreign body giant cells with polarized light microscopy. The crystals were further determined to be glutamic acid by the method of fast atom bombardment. Hence, MSG, the only composite of BCG vaccine except the bacillus, was believed to be responsible for the granulomatous foreign body reaction. On review of the literature, we could find no previous report of an adverse reaction of BCG immunization attributable to MSG (glutamic acid).

BCG Vaccine↗
PubMed2006

Viral etiology of hepatocellular carcinoma and HCV genotypes in Taiwan.

Etiologic variations of hepatocellular carcinoma (HCC) exist in different geographic areas of the world. Hepatitis B virus infection is associated with HCC. However, hepatitis C virus (HCV) infection plays an increasingly more important role in the development of HCC and is associated with more than 30% of HCC in Taiwan. The prevalence of HCV infection and HCV genotypes vary in different geographic areas. The prevalence of HCV genotype 1b (HCV-1b) was around 50-70% in Taiwan and even varied in different townships. In addition to host factors, HCV genotypes may be associated with the development of HCC. In our study, the prevalence of HCV-1b in patients with HCC was significantly higher than in those with liver cirrhosis and chronic hepatitis; multivariate analysis revealed that the disease severity was significantly correlated with age and HCV-1b. Furthermore, HCV-1b was associated with a lower response rate to interferon (IFN) therapy than HCV-2. Our study has demonstrated that mutations in the IFN sensitivity-determining region, spanning nucleotides 2,209-2,248 in the NS5A region, correlate with the sustained virological response to combination therapy with IFN and ribavirin in patients with chronic HCV-1b infection in Taiwan. A third-generation enzyme immunoassay for antibody to HCV can be used to predict viremia and monitor the virological response.

Age Factors↗
PubMed2006

Hepatic interferon receptor mRNA expression: clinical relevance and its relationship with effectiveness of interferon plus ribavirin therapy in patients with genotype 1b hepatitis C virus infection.

BACKGROUND/AIMS: Hepatic expression of interferon (IFN) receptor mRNA has been shown to correlate with the effectiveness of IFN monotherapy in patients with chronic hepatitis C virus (HCV) infection. We investigated the expression of hepatic IFN receptor alpha/beta (IFNAR2c) mRNA and its association with the effectiveness of IFN plus ribavirin (RBV) therapy and with the clinical features in patients with HCV genotype 1b (HCV-1b) infection. METHODS: A total of 42 naive patients who had chronic HCV-1b infection were treated with IFN alpha-2b 3 MU or 5 MU three times weekly plus RBV for 24 weeks. Hepatic IFNAR2c mRNA was quantified by real-time RT-PCR. RESULTS: There was no significant difference in the mean expression level of IFNAR2c mRNA between patients with sustained virological response (SVR) and non-SVR (0.069 +/-0.042 versus 0.053 +/-0.033, P=0.182). Multiple linear regression analysis showed that lower fibrosis scores (P=0.006) and younger age (P=0.03) were associated with hepatic IFNAR2c mRNA expression with r2=0.34. CONCLUSIONS: Hepatic IFNAR2c mRNA expression may not be useful for predicting the response to IFN plus RBV therapy in patients with HCV-1b infection, but appeared to correlate inversely with the fibrosis stage and age.

Adult↗
PubMed2005

Effect of ZVAD-fmk on hepatocyte apoptosis after bile duct ligation in rat.

AIM: Retention and accumulation of toxic hydrophobic bile salts within hepatocyte may cause hepatocyte toxicity by inducing apoptosis. Apoptosis is a pathway of cell death orchestrated by a family of proteases called caspases. Z-Val-Ala-Asp (OMe)-fluoromethyl ketone (ZVAD-fmk) is a cell-permeable irreversible inhibitor of caspase. The purpose of this study was to evaluate the possible effect of ZVAD-fmk on hepatocyte apoptosis after bile duct ligation in the rat. METHODS: Male Sprague-Dawley rats, weighing 250-300 g, were randomized to five groups of five rats each. Group 1 underwent common bile duct ligation and simultaneous treatment with ZVAD-fmk (dissolved in dimethylsulfoxide (DMSO)). Group 2 underwent common bile duct ligation and simultaneous treatment with Z-Phe-Ala-fluoromethyl ketone ( ZFA-fmk, dissolved in DMSO). Group 3 underwent sham operation and simultaneous treatment with the same amount of DMSO. Group 4 underwent sham operation and simultaneous treatment with the same amount of normal saline. Group 5 underwent common bile duct ligation without other manipulation. After three days, liver tissue was harv-ested for histopathologic analysis and measurements of apoptosis. RESULTS: When compared with sham operation, common bile duct ligation significantly increased hepatocyte apoptosis (P = 0.008) and ductular proliferation (P = 0.007). ZVAD-fmk significantly diminished the increased hepatocyte apoptosis and ductular proliferation after common bile duct ligation (P = 0.008 and P = 0.007, respectively). ZFA did not show the same effects. CONCLUSION: Hepatocyte apoptosis and ductular proliferation significantly increased after common bile duct ligation. ZVAD-fmk effectively diminished the increased hepatocyte apoptosis and ductular proliferation after common bile duct ligation, whereas ZFA-fmk did not.

Amino Acid Chloromethyl Ketones↗
PubMed2005

Usefulness of brilliant cresyl blue staining as an auxiliary method of screening for alpha-thalassemia.

Hemoglobin (Hb) electrophoresis is widely used in thalassemia screening. Most Hb variants express a specific abnormal band on the cellulose acetate membrane. The technique is useful in the diagnosis of the type of thalassemia but is not sensitive enough to detect alpha-thalassemia minor because the quantity of the HbH is too small to be expressed on the supporting medium. We used simple staining of blood smears rather than the sophisticated molecular method to detect HbH inclusions. To evaluate the effectiveness of this method, we used brilliant cresyl blue (BCB) staining of red blood cells in 509 patients with microcytosis and erythrocytosis caused by various conditions. The results indicate that BCB staining is useful in the identification of subjects who possess alpha-thalassemia traits. Coexisting conditions such as beta-thalassemia and iron-deficiency anemia did not affect the detection of the HbH inclusions with the use of BCB staining. We conclude that BCB staining is helpful and reliable as an auxiliary method of detecting HbH inclusions in the diagnosis of alpha-thalassemia traits, especially in places where medical resources are limited.

Coloring Agents↗
PubMed2005

Shepherd's crook deformity of polyostotic fibrous dysplasia treated with corrective osteotomy and dynamic hip screw.

Fibrous dysplasia, a condition in which the skeleton fails to develop normally, is characterized by fibroblastic stroma and immature bone. Bowing of the long bones occurs frequently in the polyostotic form, and stress fractures often result. Shepherd's crook deformity is a characteristic feature of fibrous dysplasia. The goal of its treatment is to obtain normal walking ability and relieve pain due to pathologic fracture secondary to the deformity; however, correction of the deformity is a surgical challenge. We present 2 cases of shepherd's crook deformity treated with corrective osteotomy and a dynamic hip screw. Both cases showed good bone healing and no recurrent deformity. The gross deformities were corrected, and both patients were pain-free after operation.

Adult↗
PubMed2005

Bone metastasis of Wilms' tumor with monophasic epithelial histology in a young adult.

A unique case of Wilms' tumor with monophasic epithelial histology in the bone metastasis at initial presentation in an 18-year-old Taiwanese girl is presented. Histologically, a purely differentiated epithelial component in the L1-3 vertebrae was noted, which is consistent with the epithelial component in primary Wilms' tumor of the kidney by both microscopy and immunohistochemistry. Hence, Wilms' tumor should be included in the differential diagnosis of a metastatic lesion presenting a purely epithelial histology in a young adult or a child.

Adolescent↗
PubMed2005

Recurrent Klebsiella pneumoniae liver abscess in a diabetic patient followed by Streptococcus bovis endocarditis--occult colon tumor plays an important role.

Klebsiella pneumoniae is the leading cause of liver abscess in diabetic patients in Taiwan. We report the case of a diabetic patient with a history of four episodes of K. pneumoniae liver abscess within 3 years. The patient later developed Streptococcus bovis bacteremia originating from a colon tumor with complications of endocarditis, osteomyelitis, and silent splenic abscess. Occult colon tumor may have played an important role in our case, with recurrent infection arising from colonizers of the gastrointestinal tract. As our case shows, the possible association between occult colon tumor and K. pneumoniae liver abscess in diabetic patients should be surveyed.

Adenoma, Villous↗
PubMed2004

Effect of glutamine and bile acid on hepatocyte apoptosis after bile duct ligation in the rat.

Apoptosis is an important process in a wide variety of biologic systems. Cholestasis, or impaired bile formation, occurs in a wide variety of human liver diseases. Retention and accumulation of toxic hydrophobic bile salts in hepatocytes may cause hepatocyte toxicity by inducing apoptosis. In addition, the translocation of bacteria and endotoxin, well documented in patients with obstructive jaundice, contribute to the induction of hepatocyte apoptosis. We hypothesized that oral bile acid replacement, glutamine administration, or both can attenuate or abolish hepatocyte apoptosis. Male Sprague-Dawley rats weighing 250 to 300 g were randomized to four groups (10 in each group). Group 1 underwent a sham operation and was simultaneously treated with normal saline. Group 2 underwent common bile duct (CBD) ligation and was simultaneously treated with normal saline. Group 3 underwent CBD ligation and was simultaneously treated with oral glutamine. Group 4 underwent CBD ligation and was simultaneously treated with oral bile acid replacement. After 3 days (n = 5) and 7 days (n = 5), liver tissues were harvested for histopathologic analysis and apoptosis measurements. When compared with the sham operation group, significantly increased hepatocyte apoptosis and ductular proliferation occurred after CBD ligation for either 3 or 7 days. After administration of either glutamine or bile acid, the increased hepatocyte apoptosis and ductular proliferation after CBD ligation for 3 days were significantly diminished. However, both failed to diminish the changes after CBD ligation for 7 days. Significantly increased hepatocyte apoptosis and ductular proliferation occurred after CBD ligation. The administration of either glutamine or bile acid effectively diminished the hepatocyte apoptosis and ductular proliferation after CBD ligation for 3 days, whereas both failed to show the same effect after CBD ligation for 7 days.

Administration, Oral↗
PubMed2004

Induction of G1 arrest and apoptosis in human jurkat T cells by pentagalloylglucose through inhibiting proteasome activity and elevating p27Kip1, p21Cip1/WAF1, and Bax proteins.

Pentagalloylglucose, which is found in many medicinal plants, can arrest the cell cycle at G(1) phase through down-regulation of cyclin-dependent kinases 2 and 4 and up-regulation of the cyclin-dependent kinase inhibitors p27(Kip1) and p21(Cip1/WAF1) in human breast cancer cells. Pentagalloylglucose also induces apoptosis in human leukemic cells. However, the mechanisms by which pentagalloylglucose induces these effects is unclear. We now show that pentagalloylglucose inhibits the activities of purified 20 and 26 S proteasomes in vitro, the 26 S proteasome in Jurkat T cell lysates, and chymotrypsin-like activity of the 26 S proteasome in intact Jurkat T cells. The turnover of p27(Kip1) and p21(Cip1/WAF1), which is necessary for cell cycle progression mediated by proteasome degradation, was disrupted by treatment of human Jurkat T cells with pentagalloylglucose. This was shown by cycloheximide treatment and in vivo pulse-chase labeling experiments, and this effect correlated with the arrest of proliferation of Jurkat T cells at G(1). Inhibition of the proteasome by pentagalloylglucose and by the proteasome inhibitor MG132 caused accumulation of ubiquitin-tagged proteins in Jurkat T cells. The addition of pentagalloylglucose to Jurkat T cells enhanced the stability of the proteasome substrate Bax and increased cytochrome c release and apoptosis. Our findings suggest a mechanism for the effect of pentagalloylglucose on the cell cycle in human leukemic cells: that pentagalloylglucose down-regulates proteasome-mediated pathways because it is a proteasome inhibitor.

Apoptosis↗
PubMed2004

Mechanisms of cancer chemoprevention by hop bitter acids (beer aroma) through induction of apoptosis mediated by Fas and caspase cascades.

The bitter acids of hops (Humulus lupulus L.) mainly consist of alpha-acids, beta-acids, and their oxidation products that contribute the unique aroma of the beer beverage. Hop bitter acids displayed a strong growth inhibitory effect against human leukemia HL-60 cells, with an estimated IC(50) value of 8.67 microg/mL, but were less effective against human histolytic lymphoma U937 cells. Induction of apoptosis was confirmed in HL-60 cells by DNA fragmentation and the appearance of a sub-G1 DNA peak, which were preceded by dissipation of mitochondrial membrane potential, cytochrome c release, and subsequent induction of pro-caspase-9 and -3 processing. Cleavages of PARP and DFF-45 were accompanied with activation of caspase-9 and -3 triggered by hop bitter acids in HL-60 cells. The change in the expression of Bcl-2, Bcl-X(L), and Bax in response to hop bitter acids was studied, and the Bcl-2 protein level slightly decreased; however, the Bcl-X(L) protein level was obviously decreased, whereas the Bax protein level was dramatically increased, indicating that the control of Bcl-2 family proteins by hop bitter acids might participate in the disruption of mitochondrial integrity. In addition, the results showed that hop bitter acids promoted the up-regulation of Fas and FasL prior to the processing and activation of pro-caspase-8 and cleavage of Bid, suggesting the involvement of a Fas-mediated pathway in hop bitter acids-induced cells. Taken together, these findings suggest that a certain intimate link might exist between receptor- and mitochondria-mediated death signalings that committed to cell death induced by hop bitter acids. The induction of apoptosis by hop bitter acids may offer a pivotal mechanism for their chemopreventive action.

Acids↗
PubMed2004

Comparison of clinical outcome between patients continuing and discontinuing lamivudine therapy after biochemical breakthrough of YMDD mutants.

BACKGROUND/AIMS: The aim of this study was to compare the clinical outcome between patients continuing and discontinuing lamivudine therapy after the biochemical breakthrough of hepatitis B virus tyrosine-methionine-aspartate-aspartate (YMDD) mutant. METHODS: YMDD mutants were detected in 51 chronic hepatitis B patients who experienced a flare-up of alanine aminotransferase (ALT) during lamivudine treatment. Twenty-seven of them discontinued lamivudine therapy (group A), and 24 continued therapy (group B) after biochemical breakthrough. The follow-up period was 12 months in both the groups. RESULTS: There was no significant difference between groups A and B in the incidence and severity of ALT peaks and hepatic decompensation within the first 3 months after biochemical breakthrough. After the fourth month of biochemical breakthrough, however, group A experienced acute exacerbation more frequently [20/26 (77%) vs. 7/23 (30%); P=0.002] and higher ALT peaks than group B. The same result was found when the patients were divided into naïve and retreated or cirrhotic and non-cirrhotic groups. Hepatic decompensation at the onset of biochemical breakthrough was associated with higher mortality (OR=70, 95% CI=6.06-807.75). CONCLUSIONS: Patients who discontinued lamivudine therapy increased the frequency of flare-ups and higher ALT peaks than those who continued therapy after 4 months post-breakthrough.

Adult↗
PubMed2004

Novel evolutionary relationship among four fish model systems.

Knowledge of the correct phylogenetic relationships among animals is crucial for the valid interpretation of evolutionary trends in biology. Zebrafish, medaka, pufferfish and cichilds are fish models for development, genomics and comparative genetics studies, although their phylogenetic relationships have not been tested rigorously. The results of phylogenomic analysis based on 20 nuclear protein-coding genes confirmed the basal placement of zebrafish in the fish phylogeny but revealed an unexpected relationship among the other three species, contrary to traditionally held systematic views based on morphology. Our analyses show that medaka (Beloniformes) and cichlids (Perciformes) appear to be more closely related to each other than either of them is to pufferfish (Tetraodontiformes), suggesting that a re-interpretation of some findings in comparative biology might be required. In addition, phylogenomic analyses show that fish typically have more copies of nuclear genes than land vertebrates, supporting the fish-specific genome duplication hypothesis.

Animals↗
PubMed2004

Molecular phylogeny and biogeography of Oriental voles: genus Eothenomys (Muridae, Mammalia).

Oriental voles of the genus Eothenomys are predominantly distributed along the Southeastern shoulder of the Qinghai-Tibetan Plateau. Based on phylogenetic analyses of the mitochondrial cytochrome b gene (1143 bp) obtained from 23 specimens (eight species) of Oriental voles collected from this area, together with nucleotide sequences from six specimens (two species) of Japanese red-backed voles (Eothenomys andersoni and Eothenomys smithii) and five species of the closely related genus Clethrionomys, we revised the systematic status of Eothenomys. We also tested if vicariance could explain the observed high species diversity in this area by correlating estimated divergence times to species distribution patterns and corresponding paleo-geographic events. Our results suggest that: (1) the eight species of Oriental voles form a monophyletic group with two distinct clades, and that these two clades should be considered as valid subgenera--Eothenomys and Anteliomys; (2) Eothenomys eleusis and Eothenomys miletus are not independent species; (3) Japanese red-backed voles are more closely related to the genus Clethrionomys than to continental Asian Eothenomys taxa; and (4) the genus Clethrionomys, as presently defined, is paraphyletic. In addition, the process of speciation of Oriental voles appears to be related to the Trans-Himalayan formation via three recent uplift events of the Qinghai-Tibetan Plateau within the last 3.6 million years, as well as to the effects of the mid-Quaternary ice age.

Animals↗
PubMed2003

Obstructive jaundice alters proliferating cell nuclear antigen expression in rat small intestine.

Translocation of bacteria and endotoxin has long been documented in obstructive jaundice, and altered intestinal barrier function is considered to be one of the important mechanisms for this phenomenon. Proliferating cell nuclear antigen (PCNA), also known as cyclin, is an auxiliary protein of DNA polymerase-delta, and the level of synthesis correlates directly with rates of cellular proliferation and DNA synthesis. This study was designed with the aim of evaluating the effect of obstructive jaundice on PCNA expression in small bowel epithelium. Male Sprague-Dawley rats were randomized to four groups. Group A (n = 10, control group) underwent a sham operation. Group B (n = 9, obstructive jaundice group for 1 week) underwent common bile duct ligation. Group C (n = 8, obstructive jaundice group for 2 weeks) underwent common bile duct ligation. Group D (n = 8, obstructive jaundice group for 2 weeks) underwent common bile duct ligation with oral glutamine intake. After periods of 7 days and 2 weeks, segments of small bowel were harvested from groups A & B and groups C & D, respectively. Nuclear immunohistochemical expression of PCNA in small bowel was evaluated. The PCNA-labeling index [(PCNA-positive cells/500 cells) x 100] was quantified. Comparisons among the four groups were performed. The PCNA-labeling index in small bowel of group B was significantly higher than that of group A (29.0% vs 21.2%, p = 0.001). After 2 weeks of common bile duct ligation, the PCNA-labeling index in small bowel of group C was significantly lower than that of group A (19.4% vs 21.2%, p = 0.045). With oral glutamine intake daily, the PCNA-labeling index in small bowel of Group D was restored and was significantly higher than that of group A (24.5% vs 21.2%, p = 0.002). Obstructive jaundice for 1 week upgraded PCNA expression in rat small intestine. PCNA expression in rat small intestine later became depressed after obstructive jaundice for 2 weeks. Oral glutamine intake daily could effectively restore the PCNA expression in small bowel of rats subjected to obstructive jaundice for 2 weeks.

Animals↗