Biomedical subjects

Yu-Chi Chen

Publications and source records attributed to Yu-Chi Chen.

17 recordsLinked to original sources

PubMed2007

Cloning, characterization and phylogenetic relationships of stxI, a endoxylanase-encoding gene from Streptomyces thermonitrificans NTU-88.

A thermostable xylanase gene (stxI) obtained from Streptomyces thermonitrificans NTU-88 on domain analysis revealed an N-terminal catalytic domain featuring homology to a known xylanase within the glycoside hydrolase family 11. Recombinant STXI retained more than 60% of its activity following its incubation for at 60 degrees C for 24h. These characteristics were close to thermophile and mesophile Streptomyces strains. The main hydrolysis products of xylan degraded by STXI included large xylooligosaccharide fragments. These results indicated that STXI was a typical endoxylanase. As regards the phylogenetic relationships of GH11, STXI and the other xylanase deriving from Streptomyces were included in a subgroup of the aerobic bacterial group. This result implied that the evolutionary relationships between the various xylanases deriving from Streptomyces strains were convergent.

Amino Acid Sequence↗

PubMed2006

Identification of differentially expressed genes in clear cell renal cell carcinoma by analysis of full-length enriched cDNA library.

Renal cell carcinoma (RCC) is the most common malignancy in adult kidney, and accounts for 3% of malignancies worldwide with increasing incidence. Clear cell RCC (ccRCC) is the major type in RCC. Resection by surgery is the main treatment because the response of ccRCC to traditional therapies is very poor. To identify the tumor-associated genes for better understanding the molecular mechanism of ccRCC, the full-length enriched cDNA libraries of ccRCC and normal kidney tissues were constructed by the oligo-capping method. Nucleotide sequences of the cDNA libraries of ccRCC and normal kidney tissues were sequenced. From the sequence analysis of 19,425 and 12,400 clones of ccRCC and normal kidney tissues, 4356 and 3055 genes were identified, respectively. By comparing the gene-expression patterns of ccRCC and normal tissues, the up- or down-regulated genes were identified. Among these identified genes, the differential expression of annexin A2 and argininosuccinate synthetase genes were further confirmed by quantitative real-time PCR and Western blot analysis.

Annexin A2↗

PubMed2006

Gene expression analysis of human hepatocellular carcinoma by using full-length cDNA library.

Hepatocellular carcinoma (HCC) is a leading cause of death worldwide. Hepatitis B virus (HBV) or hepatitis C virus (HCV) infection has been shown to cause hepatic carcinogenesis. A total 58,251 of cDNA clones of full-length cDNA libraries of HBV and HCV-infected HCC and their surrounding non-tumor tissues, respectively, were sequenced and analyzed by blasting against GENEBANK maintained by NCBI. About 180 and 279 of genes were shown an obviously increased and decreased expression patterns between HCC tissue and its adjacent non-tumor tissue. The candidate genes consisted of the genes encoded liver specific metabolism enzymes, secretory functional proteins, proteases and their inhibitors, protein chaperon, cell cycle components, apoptosis-related proteins, transcriptional factors, and DNA binding proteins. Several genes were further investigated by using real-time PCR to confirm the gene expression levels in at least 24 pairs of HCC tissues and adjacent non-tumor tissues. The results showed that genes encoded reticulon 4, RGS-1, antiplasmin, and kallikrein B were down-regulated with the average of 2.8, 8.5, 3.2, and 10.5-fold, respectively. Our results provide crucial candidate genes to develop clinical diagnosis and gene therapy of HCC.

Carcinoma, Hepatocellular↗

PubMed2006

[The process of empowering community development: the experience of a community in Taipei city].

Community participation and development are the most difficult aspects of building healthy communities. They are also, however, the most essential parts of the process. It has been established that empowerment can ultimately enhance individual self-efficacy, influence organizational and social structures, and increase the sense of community and citizen's capabilities. This article demonstrates the experience of one community in Taipei City during a lengthy period of organization and development. It illustrates the different stages involved in community development and the functions of community health professionals. It seeks to provide insight into the importance of using empowerment in promoting communities' capabilities and the fact that only by developing organic communities that are rich in the energy of life can we develop sustainable communities.

Community Participation↗

PubMed2005

Identification and characterization of membralin, a novel tumor-associated gene, in ovarian carcinoma.

Identification of new genes in cancer is the key to understand the molecular basis of tumor development as well as provide potential diagnostic markers and therapeutic targets. A novel gene, membralin (GeneBank accession number: DQ005958), was cloned from a human ovarian cancer cell line. Human membralin is unique and does not share significant sequence homology with other human genes, only membralins of other species. The gene contains 11 exons which encode at least two spliced variants in human cancer. The long form of membralin (membralin-1) comprises all 11 exons, encoding a protein of 620-amino acids long and the short form of membralin (membralin-3) contains all exons except for exon 10, encoding a protein of 408 amino acids. Expression of different membralin isoforms depends on tissue type. The long form, membralin-1, is expressed in ovarian and colorectal carcinomas but not in breast or pancreatic carcinomas, which express only the short splice form, membralin-3. Membralin-1-GFP fusion protein demonstrates exclusive cytoplasmic localization. Based on quantitative real-time PCR, in situ hybridization and Western blot analysis, membralin was highly expressed in ovarian serous carcinomas as compared to ovarian surface epithelium (P<0.001). Ovarian carcinomas in effusions demonstrated a significantly higher level of membralin expression than in solid tumors (P<0.001). In conclusion, these findings represent the first characterization of human membralin and suggest that membralin is a novel tumor-associated marker in ovarian serous carcinomas.

Amino Acid Sequence↗

PubMed2005

Apolipoprotein E is required for cell proliferation and survival in ovarian cancer.

Apolipoprotein E (ApoE) has been recently identified as a potential tumor-associated marker in ovarian cancer by serial analysis of gene expression. ApoE has long been known to play a key role in lipid transport, and its specific isoforms may participate in atherosclerogenesis. However, its role in human cancer is not known. In this study, apoE expression was frequently detected in ovarian serous carcinomas, the most common and lethal type of ovarian cancer. It was not detected in serous borderline tumors and normal ovarian surface epithelium. Inhibition of apoE expression using an apoE-specific siRNA led to G(2) cell cycle arrest and apoptosis in an apoE-expressing ovarian cancer cell line, OVCAR3, but not in apoE-negative cell lines. Furthermore, the phenotype of apoE siRNA-treated OVCAR3 cells was reversed by expressing engineered mutant apoE with introduced silent mutations in the siRNA target sequence. Expression of apoE in nuclei was significantly associated with a better survival in patients who presented peritoneal effusion at the time of diagnosis (5-year follow-up, P = 0.004). This study suggests a new role of apoE in cancer as apoE expression is important for the proliferation and survival in apoE-expressing ovarian cancer cells.

Apolipoproteins E↗

PubMed2005

DPPH radical-scavenging compounds from dou-chi, a soybean fermented food.

Dou-chi, a traditional soybean food fermented with Aspergillus sp., is usually used as a seasoning in Chinese food, and has also been used as a folk medicine in China and Taiwan. As 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavengers, four phenol compounds, one isoflavanone, eight isoflavones and one 4-pyrone have been isolated from dou-chi. Among these fourteen compounds, 3'-hydroxydaidzein, dihydrodaidzein and a 4-pyrone compound have not yet been isolated from soybean miso. The structure of the novel 4-pyrone compound, 3-((E)-2-carboxyethenyl)-5-(4-hydroxyphenyl)-4-pyrone-2-carboxylic acid was elucidated by using the same compound as that obtained from the biotransformation of daidzein. 3'-Hydroxydaidzein showed as high DPPH radical-scavenging activity as that of alpha-tocopherol, and 6-hydroxydaidzein had mushroom tyrosinase inhibitory activity with an IC(50) value of 10 muM. The order of estrogenic activity is as follows: genistein > daidzein >> 3'-hydroxydaidzein > 8-hydroxygenistein, using a green fluorescent protein expression system. Furthermore, the contents of isoflavones in the fermentation process of dou-chi were measured.

Antimutagenic Agents↗

PubMed2005

[A project to reduce mistakes in collecting specimens].

Specimen collection is an important task of nursing care. Any failure to collect the whole missing of a specimen may affect diagnosis and treatment. It will also increase the workloads of staff and the cost of medicines. From April to July 2002, a total of 3,382 specimens were collected in A112 ward in Taipei Veterans General hospital. There were 43 wrong specimens, 1.27% of the total. Analysis showed that the reasons for the error were as follows: (1) The level of knowledge about the test tubes and about the volume of specimens was low. (2) The procedure for dealing with application from was not appropriate. (3) The box in which specimens were kept was not appropriate. (4) The checklist was bad. The PDCA process used in this project reduced the rate of wrong specimens. The strategy was designed with three dimensions: staff, facilities, and procedure. After it was implemented, the rate of wrong specimens dropped from 1.27% to 0.49%, the improvement rate was 61.4%, and the rate of achievement was 101.3%. This project not only reduced the rate of wrong specimens, but also made the process easier and more safisfying for staff.

Humans↗

PubMed2005

The health status and health promotion behavior of low-income elderly in the Taipei area.

The purpose of this study was to understand health promotion behaviors and their correlated factors among low-income elderly in the Taipei area. This study used a cross-sectional design with a descriptive correlation approach. A total of 89 low-income elderly from Peitou District of Taipei participated in the study. Structured questionnaires, the primary sources of measurement, were read to study subjects by a trained research assistant. The mean age of low-income elderly in the study was 76.85 year-old. A plurality were single (41.6%) and 31.5% lived alone. Subject IADLs (instrumental activities of daily living) were not as good as their ADLs (activities of daily living). Their psychosocial health status was worse than their physical health status. Among health promotion behaviors, regular exercise appears to be the most prevalent. The most significant factor among subjects for failing to follow health-promoting behaviors was their IADLs. Homebound elderly who lived alone and had poor IADL were less likely to have health promoting behaviors. A proposal to encourage health promotion behaviors for low-income elderly derived from study results is the initiation of formal personal assistance programs to remedy the inability of many elderly, especially those living alone, to leave the home due to ADL-related or other limitations.

Activities of Daily Living↗

PubMed2005

[Application of empowering education in long-term care facilities: the experience with foreign nurse aides].

The concept of empowerment, widely accepted and utilized in many health-related disciplines, connotes a process of gaining control over one's life and influencing the organizational and social structures in which one lives. This article demonstrates an example of how empowering education can be applied on foreign nursing aides working in long-term care facilities and how differing empowering strategies, processes and effects can be adopted to address differing situations and ethnic backgrounds. How high priority issues of concern for foreign nurses are handled impacts upon their ability to perform their jobs well. Empowering strategies can help deal with such issues more effectively and, as a result, reduce work stress and improve on-the-job performance. During the preparation stage, the empowerment process focuses on building a trusting partner relationship. During the work stage, the process focuses on inspiring foreign nurses' self-awareness, encouraging their perceiving the barriers and needs at work, and, most importantly, encouraging nurses to think critically and positively and to provide feedback. The effects of empowering education include enhanced problem solving abilities, rising nurse self-confidence in his/her caretaking abilities, enhanced self-esteem, and improved adaptation to the work environment. This paper provides empirical experiences with regard to the application of empowering education in clinical settings as well as process and management strategies related to foreign nursing aides employed in long-term care facilities.

Foreign Professional Personnel↗

PubMed2004

Nutritionally variant streptococcal infections at a University Hospital in Taiwan: disease emergence and high prevalence of beta-lactam and macrolide resistance.

From January 1993 to December 2002, 28 patients with nutritionally variant streptococci (NVS) infections were treated at a university hospital in Taiwan. Twelve (43%) of these patients had various underlying malignancies, and 7 (25%) had underlying valvular heart diseases. Nine patients (32%) had infective endocarditis, and 9 (32%) had primary bacteremia. The deaths of 7 patients (25%) were directly related to NVS infection. Among the 28 isolates recovered from these patients, 50% were not susceptible to penicillin, 33% were not susceptible to cefotaxime, and 93% were not susceptible to azithromycin.

Adolescent↗

PubMed2004

Using siRNA technique to generate transgenic animals with spatiotemporal and conditional gene knockdown.

Based on the RNAi technique, we have developed a new approach that generates transgenic animals capable of mimicking human genetic diseases. The new system is a combination of siRNA with Cre-loxP and tetracycline-on. It has the characteristics of being stable, inheritable, and inducible, with the siRNA able to be transcribed tissue specifically. To support the ability of this new method to generate a model for a disease, we created an ABCA1-deficient mouse line that mimics Tangier disease under controlled conditions. Thus, it should now be possible to rapidly establish human genetic diseases as a whole animal model without the use of embryonic stem cell and gene targeting. This system also provides a tool for pathological and pharmacological studies of aspects peculiar to particular human genetic diseases.

ATP Binding Cassette Transporter 1↗

PubMed2004

Isolation of 8-hydroxyglycitein and 6-hydroxydaidzein from soybean miso.

We isolated from soybean miso 8-hydroxyglycitein and 6-hydroxydaidzein as DPPH-radical scavengers, and elucidated their chemical structures by mass spectrometric, and (1)H- and (13)C-NMR spectrosopic analyses. These compounds showed DPPH-radical scavenging activity as high as that of alpha-tocopherol, 8-hydroxygenistein and 8-hydroxydaidzein. This is the first report of the isolation of 8-hydroxyglycitein from a natural source.

Biphenyl Compounds↗

PubMed2003

HLA-G is a potential tumor marker in malignant ascites.

PURPOSE: Molecular approaches as supplements to cytological examination of malignant ascites may play an important role in the clinical management of cancer patients. HLA-G is a potential tumor-associated marker and that one of its isoforms, HLA-G5, produces a secretory protein. This study is to assess the clinical utility of secreted HLA-G levels in differential diagnosis of malignant ascites. EXPERIMENTAL DESIGN: We used ELISA to assess whether secretory HLA-G (sHLA-G) could serve as a marker of malignant ascites in ovarian and breast carcinomas, which represent the most common malignant tumors causing ascites in women. RESULTS: On the basis of immunohistochemistry, 45 (61%) of 74 ovarian serous carcinomas and 22 (25%) invasive ductal carcinomas of the breast demonstrated HLA-G immunoreactivity ranging from 2 to 100% of the tumor cells. HLA-G staining was not detected in a wide variety of normal tissues, including ovarian surface epithelium and normal breast tissue. Revese transcription-PCR demonstrated the presence of HLA-G5 isoform in all of the tumor samples expressing HLA-G. ELISA was performed to measure the sHLA-G in 42 malignant and 18 benign ascites supernatants. sHLA-G levels were significantly higher in malignant ascites than in benign controls (P < 0.001). We found that the area under the receiver-operating characteristic curve for sHLA-G was 0.95 for malignant versus benign ascites specimens. At 100% specificity, the highest sensitivity to detect malignant ascites was 78% (95% confidence interval, 68-88%) at a cutoff of 13 ng/ml. CONCLUSIONS: Our findings suggest that measurement of sHLA-G is a useful molecular adjunct to cytology in the differential diagnosis of malignant versus benign ascites.

Ascites↗

PubMed2003

Increased plasma DNA integrity in cancer patients.

Tumor-released DNA in blood represents a promising biomarker for cancer detection. It has been postulated that tumor necrosis causes release of DNA of varying sizes, which contrasts apoptosis in normal tissue that releases smaller and more uniform DNA fragments. To test the hypothesis that increased DNA integrity, i.e., a longer DNA strand, is a tumor-associated marker in plasma, we determined the genomic DNA integrity index in plasma DNA using real-time PCR assays. A DNA integrity index and DNA concentration in plasma were determined in 61 patients with gynecological and breast cancers and 65 female patients without neoplastic diseases. We found that the area under the receiver-operating characteristic curve for DNA integrity index was 0.911 for cancer versus nonneoplastic patients. Given 100% specificity, the highest sensitivity achieved in detecting the cancer group was 62% (95% confidence interval = 0.50-0.74) at the index cutoff of 0.59. Fifty percent of stage I cancers had a DNA integrity index above this cutoff. All 11 patients with benign adnexal masses that clinically can be confused with malignant gynecological neoplasms demonstrated DNA integrity index < 0.59. Our findings suggest that increased DNA integrity in plasma DNA is associated with cancer, and measurement of DNA integrity may provide a simple and inexpensive measure for cancer detection.

Case-Control Studies↗

PubMed2003

Identifying tumor origin using a gene expression-based classification map.

Identifying the primary site in cases of metastatic carcinoma of unknown origin has profound clinical importance in managing cancer patients. Although transcriptional profiling promises molecular solutions to this clinical challenge, simpler and more reliable methods for this purpose are needed. A training set of 11 serial analysis of gene expression (SAGE) libraries was analyzed using a combination of supervised and unsupervised computational methods to select a small group of candidate genes with maximal power to discriminate carcinomas of different tissue origins. Quantitative real-time PCR was used to measure their expression levels in an independent validation set of 62 samples of ovarian, breast, colon, and pancreatic adenocarcinomas and normal ovarian surface epithelial controls. The diagnostic power of this set of genes was evaluated using unsupervised cluster analysis methods. From the training set of 21,321 unique SAGE transcript tags derived from 11 libraries, five genes were identified with expression patterns that distinguished four types of adenocarcinomas. Quantitative real-time PCR expression data obtained from the validation set clustered tumor samples in an unsupervised manner, generating a self-organized map with distinctive tumor site-specific domains. Eighty-one percent (50 of 62) of the carcinomas were correctly allocated in their corresponding diagnostic regions. Metastases clustered tightly with their corresponding primary tumors. A classification map diagnostic of tumor types was generated based on expression patterns of five genes selected from the SAGE database. This expression map analysis may provide a reliable and practical approach to determine tumor type in cases of metastatic carcinoma of clinically unknown origin.

Adenocarcinoma↗

PubMed2003

Involvement of hydrogen peroxide and nitric oxide in expression of the ipomoelin gene from sweet potato.

The IPO (ipomoelin) gene was isolated from sweet potato (Ipomoea batatas cv Tainung 57) and used as a molecular probe to investigate its regulation by hydrogen peroxide (H(2)O(2)) and nitric oxide (NO) after sweet potato was wounded. The expression of the IPO gene was stimulated by H(2)O(2) whether or not the plant was wounded, but its expression after wounding was totally suppressed by the presence of diphenylene iodonium, an inhibitor of NADPH oxidase, both in the local and systemic leaves of sweet potato. These results imply that a signal transduction resulting from the mechanical wounding of sweet potato may involve NADPH oxidase, which produces endogenous H(2)O(2) to stimulate the expression of the IPO gene. The production of H(2)O(2) was also required for methyl jasmonate to stimulate the IPO gene expression. On the contrary, NO delayed the expression of the IPO gene, whereas N(G)-monomethyl-L-arginine monoacetate, an inhibitor of NO synthase, enhanced the expression of the IPO gene after the plant was wounded. This study also demonstrates that the production of H(2)O(2) stained with 3,3'-diaminobenzidine hydrochloride could be stimulated by wounding but was suppressed in the presence of NO. Meanwhile, the generation of NO was visualized by confocal scanning microscope in the presence of 4,5-diaminofluorescein diacetate after sweet potato was wounded. In conclusion, when sweet potato was wounded, both H(2)O(2) and NO were produced to modulate the plant's defense system. Together, H(2)O(2) and NO regulate the expression of the IPO gene, and their interaction might further stimulate plants to protect themselves from invasions by pathogens and herbivores.

Acetates↗