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Kung-Chia Young

Publications and source records attributed to Kung-Chia Young.

15 recordsLinked to original sources
PubMed2006

CD81 down-regulation on B cells is associated with the response to interferon-alpha-based treatment for chronic hepatitis C virus infection.

The lymphocytic CD81 molecule, capable of modulating type-1/-2 T-helper responses and serving as a putative receptor for hepatitis C virus (HCV), might influence the outcome of anti-HCV treatment. This study characterized the interferon-alpha-induced alteration of lymphocytic CD81. The CD81 levels in healthy subjects and naïve chronic HCV patients were compared, with the results showing that the two groups had comparable surface CD81 levels for total peripheral blood lymphocytes, subpopulation-B, -T, and -NK cells. In vitro interferon-alpha treatment could suppress the CD81 expression from both groups. Subsequently, we compared the in vitro interferon-alpha modulatory effects on lymphocytic CD81 from patients having received anti-HCV therapy with either sustained virological response (SVR) or without SVR. There was a significant down-regulation of the B-cell's CD81 only in the SVR group. The CD81 modulation was further investigated using Daudi lymphoid cell line, showing declined surface CD81 levels following treatment with interferon-alpha, interferon-beta or polyI:C. Thus, interferons could directly decrease CD81 expression. The interferon-alpha effect could be restored by 2-aminopurine, suggesting that double-stranded RNA activated kinase might be involved in the suppression of CD81. In conclusion, CD81 down-regulation is a primary host response to interferon-alpha-based therapy and an immunophenotype associated with anti-HCV SVR.

Adult↗
PubMed2006

Seroprevalence of hepatitis E virus infection among institutionalized psychiatric patients in Taiwan.

BACKGROUND: Hepatitis E virus infection (HEV) remains unclear in institutionalized psychiatric patients. OBJECTIVES: To investigate the prevalence and risk factors of HEV infection in a psychiatric institution in Taiwan. STUDY DESIGN: A total of 754 patients with psychiatric disorders were enrolled in the study. Clinical features, review of patient charts, and interviews with families were recorded for analysis. Antibody to HEV was tested using a commercial enzyme-linked immunosorbent assays. RESULTS: The prevalence of HEV infection in institutionalized patients was as high as 14.5%. Males had higher prevalence than females. It was also found prevalence increased significantly by age group. When compared with patients 30 years old or less, those in the 31-40 year old age group had an odds ratio of 4.89 [95% confidence interval (CI), 1.15-20.82], 41-50 years old of 6.30 (95% CI, 1.48-26.83), and 50 years or older of 6.20 (95% CI, 1.44-26.74). In multivariate logistic regression analysis, age and male gender were the independent risk factors. CONCLUSIONS: Institutionalized psychiatric patients had higher prevalence of HEV infection. In addition, there was an age-related increase in exposure to HEV with males that had a higher HEV seropositivity.

Adult↗
PubMed2006

Simultaneous quantification and genotyping of hepatitis B virus for genotypes A to G by real-time PCR and two-step melting curve analysis.

Both the viral titer and the genotype significantly determine clinical outcomes and responses to antiviral treatment in chronic hepatitis B virus (HBV) infection. A method was developed for large-scale A-to-G genotyping with simultaneous viral quantification. The assay was run on a LightCycler instrument using hybridization probes. The genotype was determined from the melting points of the probes in a two-step manner. Set 1 amplicons differentiated genotypes B, E, and F from A, C, D, and G and simultaneously quantified viremia by real-time PCR. Melting curve analysis using the set 2-1 amplicon or the set 2-2 amplicon reaction mixture was then used to differentiate these genotype groups into single genotypes. HBV DNA quantification was consistent with that of the Amplicor assay and linear in a range from 10(2) to 10(13) copies/ml. By comparison with the restriction fragment length polymorphism method, 92.3% of 441 samples were accurately genotyped by the current assay. The method should be useful for genotyping and quantification of HBV DNA in areas where all genotypes exist.

DNA Primers↗
PubMed2004

Estrogen receptor-alpha polymorphism in a Taiwanese clinical breast cancer population: a case-control study.

INTRODUCTION: Receptor-mediated estrogen activation participates in the development and progression of breast cancer. Estrogen receptor (ER)-alpha polymorphism has been found to be associated with breast cancer and clinical features of the disease in Caucasians. Epidemiologic studies have revealed that age-incidence patterns of breast cancer in Asians differ from those in Caucasians. Genomic data for ER-alpha in either population is therefore of value in the clinical setting for that ethnic group. METHODS: A case-control study was conducted to establish a database of ER-alpha polymorphisms in a Taiwanese population in order to compare Western and Taiwanese (Asian) distributions and to evaluate ER-alpha polymorphism as an indicator of clinical outcome. The ER-alpha gene was scanned in a Taiwanese clinical breast cancer group (189 patients) and in healthy individuals (177 healthy control individuals). PCR single-strand conformation polymorphism technology was employed and real-time PCR melting curve analysis was performed. RESULTS: Three sites of silent single nucleotide polymorphism (SNPs) were found, as reported previously in Western studies, but at significantly different frequencies. Among the three SNPs, the frequency of allele 1 (TCT --> TCC) in codon 10 was significantly lower in breast cancer patients (32.0%) than in control individuals (40.4%; P = 0.018). We found that allele 1 (ACG --> ACA) in codon 594 was less common in breast cancer patients with a family history of breast cancer (5.9%) than in those without such a history (19.6%; P = 0.049). Individually, both allele 1 in codon 325 (CCC --> CCG) and allele 1 in codon 594 exhibited a reverse association with the occurrence of lymph node metastasis. Furthermore, incorporation of both SNP markers further increased predictive accuracy. CONCLUSIONS: Our data suggest that ER-alpha polymorphisms are correlated with various aspects of breast cancer in Taiwan. ER-alpha genotype, as determined during presurgical evaluation, might represent a surrogate marker for predicting breast cancer lymph node metastasis.

Adult↗
PubMed2004

The mRNA profile of genes in betel quid chewing oral cancer patients.

Oral cancer is one of the most common types of human cancer in the world. Although the risk factors for oral cancer are well-recognized in different countries, the molecular mechanism responsible for this malignancy remains elusive particularly in the countries where betel quid chewing is prevalent. The cDNA microarray analysis was used to analyse the mRNA expression patterns of 1177 genes in ten oral cancer patients with betel quid chewing history. Eighty-four genes involving cell adhesion, cell shape, growth, apoptosis, angiogenesis, metastasis, and metabolism were deregulated. Although the expression profile of these genes was shared by certain clinical patients, there was no significant association of the expression profile with clinical staging. Functional implication of four validated genes including caspase-1, STAT-1, COX-2 and pleiotrophin was discussed. This study provides pilot data for understanding the pathogenesis of oral cancer in countries like Taiwan where betel quid chewing is prevalent.

Adult↗
PubMed2003

Mutagenic and inhibitory effects of ribavirin on hepatitis C virus RNA polymerase.

Crotty et al. recently proposed the primary antiviral action of ribavirin to be that of a potent RNA mutagen [Crotty, S., Maag, D., Arnold, J. J., Zhong, W., Lau, J. Y., Hong, Z., Andino, R., and Cameron, C. E. (2000) Nat. Med. 6, 1375-1379]. Here we investigate the effect of ribavirin triphosphate (RTP) on RNA synthesis catalyzed by a full-length hepatitis C virus (HCV) RNA polymerase in vitro. HCV polymerase can use RTP as a nucleotide substrate in a template-dependent manner, incorporating it opposite a pyrimidine (C or U) template residue, but not a purine (A or G). Kinetic analysis revealed that incorporation of ribavirin monophosphate (RMP) across from C is 3 times more efficient catalytically than that across from U, as determined by the k(cat)/K(m) parameter. The efficiency of RMP incorporation, however, is 50-100 fold lower than that of the natural NMP. RMP incorporation does not lead to termination of RNA chain synthesis, as evidenced by the ability of the polymerase to extend its RNA product many nucleotides beyond the site of RMP incorporation. However, multiple-RMP incorporation at low GTP concentrations induced the formation of stalled elongation complexes, particularly at the template region containing consecutive C residues. Most, but not all, such elongation blocks can be relieved by the re-addition of GTP. When ribavirin is present in the RNA template, pyrimidine (but neither purine nor ribavirin) monophosphate is incorporated opposite ribavirin, but at an exceedingly low catalytic efficiency (200-3000-fold lower) compared to the efficiencies of those templated by A or G. Consequently, the level of RNA synthesis on a ribavirin-containing template is significantly reduced. These findings suggest that ribavirin not only is mutagenic but also interferes with HCV polymerase-mediated RNA synthesis.

Antiviral Agents↗
PubMed2003

Identification of a ribavirin-resistant NS5B mutation of hepatitis C virus during ribavirin monotherapy.

Ribavirin (RBV), a guanosine analogue, has been suggested to exert an antiviral action against hepatitis C virus (HCV) by causing lethal mutations and suppressing RNA polymerase in vitro, but the mechanism of its clinical therapeutic effects is currently unknown. To test the hypothesis that RBV could act both as an RNA mutagen and inhibit viral RNA synthesis in vivo, we studied the evolution of the nucleotide sequences of HCV RNA at the nonstructural (NS) 5B region in patients receiving RBV, placebo, or interferon alfa (IFN-alpha) monotherapy. The RBV group showed a slightly more accelerated evolution rate of HCV RNA quasispecies than either the IFN-alpha or placebo group. RBV caused preferentially A-to-G and U-to-A mutations. Interestingly, an NS5B amino acid 415 Phe-to-Tyr (F415Y) mutation emerged in all (5 of 5) patients infected with HCV genotype 1a during the RBV treatment. Subsequently, the parental 415F strain reemerged in some patients after the treatment was discontinued. The effect of the amino acid substitution at NS5B415 on HCV RNA replication was then investigated using an HCV subgenomic replicon in Huh7 cells. We showed that treatment of replicon cells with RBV reduced the HCV RNA level of NS5B415F replicon, but not NS5B415Y, in a dose-dependent manner. Thus, NS5B F415Y mutation represents an RBV-resistant variant. The 3-dimensional modeling and structure analysis of NS5B protein revealed that the 415th amino acid is located at the P helix region of the thumb subdomain, which may interact with the minor groove of the template-primer duplex in the putative RNA-binding cleft. In conclusion, RBV could work as a weak mutagen for HCV RNA in HCV-infected patients. Furthermore, the selection of an RBV-resistant variant with a single amino acid substitution in NS5B suggested that RBV may directly interact with HCV RNA polymerase, thus interfering with its enzymatic activity.

Adult↗
PubMed2002

Two UVC-induced stress response pathways in HeLa cells identified by cDNA microarray.

Environmental toxins induce multiple effects in vivo, involving various molecular pathways. The ultraviolet C (UVC, 254 nm) component of sunlight can cause strong cytotoxic and genotoxic effects. In this study, UVC-induced stress response factors were analyzed by cDNA microarray, using the Millennium(R) Nylon membrane chip system. HeLa cells were irradiated with 30 Joule/m(2)/sec UVC, incubated for 30 or 60 minutes and then subjected to the analysis. Multiple chips were used for each experimental condition so that the data could be analyzed statistically. Principal component analysis (PCA) was used to identify groups of genes whose expression changed in a similar manner with time post-UVC irradiation. Three major factors were identified, depending on the directionality of expression changes in each gene. The factor loadings in all three identified gene groups were high, indicating that genes within each group were highly correlated. Two factors exhibited significantly changed expression patterns after 30 minutes of incubation but in the opposite direction. This indicates that the "immediate early" UVC-induced stress response was elicited by two major pathways. Interestingly, expression of the genomic damage-inducible GADD genes, as well as p53, was initially decreased, unlike the "immediate early" genes Fos/Jun and Egr-1, which were strongly increased after 30 minutes of incubation. The results indicate that PCA used in the analysis of pre-hypothesized, functionally related genes can identify the potential subpathways in a group. This method provides a novel approach for identifying functionally-related genes in microarray studies.

Enzymes↗
PubMed2002

Variation of hepatitis C virus load, hypervariable region 1 quasispecies and CD81 hepatocyte expression in hepatocellular carcinoma and adjacent non-cancerous liver.

Hepatitis C virus (HCV) infection is etiologically associated with the development of hepatocellular carcinoma (HCC) worldwide. HCV has been reported to exist and replicate in both HCC and adjacent non-cancerous liver tissue, but limited information was available on HCV viral load and quasispecies composition in HCC relative to adjacent non-cancerous hepatocytes. Previous study has also suggested CD81, a surface hepatocyte protein, as a receptor for HCV. To clarify the above, HCV-RNA and CD81-RNA titers in 20 paired hepatectomized liver and serum were quantitatively measured by chemiluminescent RT-cPCR. Hypervariable region 1 (HVR-1) variations of parallel specimens were analyzed after subcloning in 6 patients. HCV-RNA levels in serum and non-cancerous liver were markedly higher for HCV genotype 1 than genotype non-1. HCV levels were markedly higher in non-cancerous liver than in HCC (P = 0.001) in a genotype-independent manner, with a mean ratio of 56:1 for non-cancerous tissue to HCC. Both non-cancerous and HCC tissues had the same level of CD81-RNA expression, which was not linked to HCV load. HCV-RNA quantity in both HCC and non-cancerous liver correlated with the number of HVR-1 quasispecies in the tissue, and distinct HVR-1 subclones existed.

Adult↗
PubMed2002

A reverse-transcription competitive PCR assay based on chemiluminescence hybridization for detection and quantification of hepatitis C virus RNA.

A reverse-transcription competitive PCR (RT-cPCR) combined with chemiluminescence hybridization was designed for the detection and quantitative determination of serum hepatitis C virus (HCV) RNA. The concentration of HCV RNA was calculated based on an external standard curve that was generated by coamplification of internal competitor and target sequences in serial dilutions. The detection limit of the chemiluminescence RT-cPCR was 100 copies/ml (94 IU/ml). Meanwhile, the linear range for quantitation extended from 850 copies/ml (795 IU/ml) to 4.95x10(7) copies/ml. The performance of the current assay for measuring circulating HCV levels from 26 anti-HCV-antibody positive patients was compared with that of branched-chain DNA (bDNA) and nested RT-PCR assays. Eighteen patients had HCV RNA levels that exceeded the quantitation limit by the chemiluminescence RT-cPCR, but only 11 patients were quantitation-positive by the bDNA. A significant correlation of the quantitation values was found between the chemiluminescence RT-cPCR and the bDNA (R2=0.8391). Among the eight patients with HCV RNA titers below the quantitation limit, four remained positive by the chemiluminescence cRT-PCR, demonstrating the results in agreement with those using the nested RT-PCR. Furthermore, good linearity was revealed for the HCV genotypes 1b, 2a, 2b in 3-order magnitude diluted serum samples. In conclusion, the proposed chemiluminescence RT-cPCR method can detect quantitatively HCV RNA as accurately as the bDNA method and has sensitivity as high as nested RT-PCR.

Branched DNA Signal Amplification Assay↗
PubMedDate not supplied

Molecular evidence for transmission of GB virus-C/Hepatitis G virus infection within family: close relationship between mother and child.

BACKGROUND/AIMS: GBV-C/Hepatitis G virus (HGV) is transmitted parentally, but some of the transmitted routes are still unclear. This study was conducted to investigate the relationship of family members in the transmission of HGV. METHODOLOGY: The study group enrolled 11 children from four index mothers with HGV viremia, whereas the control group had 14 children from seven matched mothers without HGV infection. Detection of circulating HGV RNA and anti-E2 antibody was conducted. Comparison of partially HGV nucleotide sequences at the 5' non-coding and non-structure 5 regions was performed among the infected family members. RESULTS: There was higher HGV viremia in children from the index mothers with HGV infection than those from mothers in control (3/11 vs. 0/14, p < 0.05). Nucleotide sequences analysis showed higher similarity between mothers and their children in the same family (98.6% to 100%) than between mothers of different families (87.8% to 92.4%). The phylogenetic construction also demonstrated distinct sequence clusters for mother and child/children of each family. CONCLUSIONS: The relationship of HGV transmission between mother and children was closely related in family. Spread of HGV might occur intrafamilially.

Adolescent↗
PubMedDate not supplied

High-dose interferon-alpha 2b plus ribavirin combination therapy for GB virus-C/hepatitis G virus infection--a study in patients with chronic hepatitis C.

BACKGROUND/AIMS: The efficacy of interferon-alpha and ribavirin combination therapy for GB virus C/hepatitis G virus infection is not well understood. We previously conducted a double-blind, placebo-controlled trial using high-dose interferon-alpha 2b with or without ribavirin for patients with interferon-alpha-relapsed chronic hepatitis C. METHODOLOGY: Fifty-two patients were randomly assigned and completed the 24-week treatment of interferon-alpha 2b (6 million units three times per week) plus ribavirin (1000 to 1200 mg/daily), or plus a matched placebo. Patients were then followed for an additional 24 weeks. RESULTS: Of the 52 patients, 5 patients (9.6%) had hepatitis G virus viremia before or during enrollment. Two patients received interferon-alpha 2b alone and three patients received interferon-alpha 2b and ribavirin combination therapy. At the end of treatment, all of the 5 patients had undetectable hepatitis G virus RNA in sera. Early loss of hepatitis G virus RNA at week 4 of treatment was observed in the 2 patients on combination therapy. Hepatitis G virus RNA reappeared at the end of follow-up in these 5 patients. CONCLUSIONS: In conclusion, interferon-alpha 2b and ribavirin combination therapy could induce earlier loss of hepatitis G virus RNA than interferon-alpha 2b alone. Either interferon-alpha 2b alone or interferon-alpha 2b and ribavirin combination therapy achieved transient but not sustained virological response to hepatitis G virus viremia.

Adult↗
PubMedDate not supplied

Immune response to hepatitis B vaccine of subjects with isolated antibody to hepatitis B core antigen.

BACKGROUND/AIMS: For subjects with isolated antibody to hepatitis B core antigen, vaccination can help discriminate various diagnostic possibilities. The aim of this study was to evaluate the clinical significance of isolated antibody to hepatitis B core antigen. METHODOLOGY: A total of 1403 hospital personnel were screened for hepatitis B surface antigen, antibody to hepatitis B surface antigen and antibody to hepatitis B core antigen by radioimmunoassay. Thirty subjects were confirmed to have isolated antibody to hepatitis B core antigen, and 278 subjects lacked all hepatitis B virus markers. Twenty-five of the 30 subjects (group I) and 136 of the 278 subjects (group II) were vaccinated by hepatitis B vaccine at months 0, 1, 6; followed by checking antibody to hepatitis B surface antigen in geometric mean titres at months 1, 2, and 7. RESULTS: The geometric mean titres of antibody to hepatitis B surface antigen were higher in group I than in group II at month 1 (9.1 +/- 8.6 vs. 3.2 +/- 6.0, p < 0.05), and were lower in group I than group II at month 7 (267.2 +/- 17.2 vs. 2315.3 +/- 5.1, p < 0.05). Furthermore, primary response was higher in group II than group I (73.3% vs. 35.7%, p < 0.05), but anamnestic response and non-response were higher in group I than group II (50% vs 26.7%, p = 0.116 with a trend; 14.3% vs. 0%, p < 0.01, respectively). CONCLUSIONS: For subjects with isolated antibody to hepatitis B core antigen, a strategy concerning sequential vaccination followed by checking antibody to hepatitis B surface antigen might be adopted to avoid two extra vaccine dosages and ineffective vaccination.

Adult↗
PubMedDate not supplied

Interspousal transmission of hepatitis C virus: application of comparing the variability of HVR1 nucleotide region.

BACKGROUND/AIMS: The interspousal transmission of hepatitis C virus (HCV) has been a controversial issue in previous studies. We thus aim to investigate the possibility of HCV transmission between spouses by comparing the variability of HCV hypervariable region 1 (HVR1) between spouses and non-spouses. METHODOLOGY: Four spouses both positive for anti-HCV antibody and HCV RNA were enrolled in our study. Reverse transcriptional polymerase chain reaction (PCR) of HVR1 region was done from each patient for blood samples. The amplified PCR products were molecularly cloned, and eight to ten clones from each patient were analyzed. In addition to the phylogenetic analysis, comparing the variability of nucleotide and deduced amino acid sequences of HVR1 and outside HVR1 from these clones by a computer software program PHYLIP version 3.57 was performed in each patient, between spouse and among non-family patients. RESULTS: All eight patients were infected with genotype Ib HCV. The sequences of eight to ten clones of HCV HVR1 in each patient showed quasispecies nature of HCV. Moreover, the variabilities of nucleotide sequence and deduced amino acid sequence of HVR1 were much higher than those outside of HVR1. Between spouses, the variabilities of HVR1 were significantly lower (p<0.001) than those of non-family members in 3 of 4 families. Clones of the same patient displayed the closest relationship in the phylogenetic tree. In addition, spouses of three families showed a closer relationship than other non-family patients. CONCLUSIONS: This study strongly suggests that sexual transmission does exist, which can be confirmed by comparing the variability of HVR1 nucleotide region of HCV.

Female↗