Biomedical subjects

Chuan-Mu Chen

Publications and source records attributed to Chuan-Mu Chen.

22 records · Page 2Linked to original sources

PubMed2002

Applications of CpG island microarrays for high-throughput analysis of DNA methylation.

Differential methylation hybridization (DMH) is a high-throughput microarray technique designed to identify changes in DNA methylation patterns commonly observed in cancer and other disease states. The DMH methodology comprises three fundamental components: the arraying of CpG island clones on glass slides, the preparation of the sample amplicons under investigation, and the hybridization of amplicon targets onto the CpG island microarray. Herein, we outline the DMH protocol and illustrate its utility and the validation approaches used in analyzing the hypermethylation profile of breast tumor and normal samples.

CpG Islands↗

PubMed2002

Methylation-specific oligonucleotide microarray: a new potential for high-throughput methylation analysis.

Oligonucleotide microarray-based hybridization is an emerging technology for genome-wide detection of DNA variations. We have extended this principle and developed a novel approach, called methylation-specific oligonucleotide (MSO) microarray, for detecting changes of DNA methylation in cancer. The method uses bisulfite-modified DNA as a template for PCR amplification, resulting in conversion of unmethylated cytosine, but not methylated cytosine, into thymine within CpG islands of interest. The amplified product, therefore, may contain a pool of DNA fragments with altered nucleotide sequences due to differential methylation status. A test sample is hybridized to a set of oligonucleotide (19-23 nucleotides in length) arrays that discriminate methylated and unmethylated cytosine at specific nucleotide positions, and quantitative differences in hybridization are determined by fluorescence analysis. A unique control system is also implemented to test the accuracy and reproducibility of oligonucleotides designed for microarray hybridization. This MSO microarray was applied to map methylated CpG sites within the human estrogen receptor alpha (ERalpha) gene CpG island in breast cancer cell lines, normal fibroblasts, breast tumors, and normal controls. Methylation patterns of the breast cancer cell lines, determined by MSO microarray, were further validated by bisulfite nucleotide sequencing (P <0.001). This proof-of-principle study shows that MSO microarray is a promising technique for mapping methylation changes in multiple CpG island loci and for generating epigenetic profiles in cancer.

Base Sequence↗

PubMed2002

Cefuroxime-impregnated cement in primary total knee arthroplasty: a prospective, randomized study of three hundred and forty knees.

BACKGROUND: A prospective, randomized study was conducted to evaluate the efficacy of cefuroxime-impregnated cement in the prevention of deep infection after primary total knee arthroplasties performed without so-called clean-air measures, such as laminar flow and body-exhaust suits. METHODS: Three hundred and forty primary total knee arthroplasties were performed with cementless fixation of the femoral component and cement fixation of the patellar and tibial components. The knees were randomly divided into two groups. In Group 1 (178 knees), cefuroxime-impregnated cement was used for fixation, whereas in Group 2 (162 knees), the cement did not contain cefuroxime. There was no significant difference between the two groups regarding demographic variables, the preoperative or postoperative knee score, the duration of the operation or of the use of the tourniquet, or the amount of blood transfused perioperatively. The average duration of follow-up was forty-nine months (range, twenty-six to eighty months). RESULTS: No deep infection developed in the 178 knees in Group 1, whereas a deep infection developed in five (3.1%) of the 162 knees in Group 2 (p = 0.0238). Two superficial wound infections developed in each group. CONCLUSIONS: Cefuroxime-impregnated cement was shown to be effective in the prevention of early to intermediate deep infection after primary total knee arthroplasty performed with use of perioperative systemic antibiotic prophylaxis but no so-called clean-air measures.

Adult↗

PubMed2002

Methylation microarray analysis of late-stage ovarian carcinomas distinguishes progression-free survival in patients and identifies candidate epigenetic markers.

PURPOSE: The purpose of this study was to profile methylation alterations of CpG islands in ovarian tumors and to identify candidate markers for diagnosis and prognosis of the disease. EXPERIMENTAL DESIGN: A global analysis of DNA methylation using a novel microarray approach called differential methylation hybridization was performed on 19 patients with stage III and IV ovarian carcinomas. RESULTS: Hierarchical clustering identified two groups of patients with distinct methylation profiles. Tumors from group 1 contained high levels of concurrent methylation, whereas group 2 tumors had lower tumor methylation levels. The duration of progression-free survival after chemotherapy was significantly shorter for patients in group 1 compared with group 2 (P < 0.001). Differential methylation in tumors was independently confirmed by methylation-specific PCR. CONCLUSIONS: The data suggest that a higher degree of CpG island methylation is associated with early disease recurrence after chemotherapy. The differential methylation hybridization assay also identified a select group of CpG island loci that are potentially useful as epigenetic markers for predicting treatment outcome in ovarian cancer patients.

Biomarkers, Tumor↗