Detection of Fecal DNA Methylation for Colorectal Neoplasia : Does It Lead to an Optimal Screening Test?

Aberrant promoter methylation, an 'epigenetic' form of genomic instability that leads to transcriptional silencing of tumor suppressor genes, is increasingly being recognized as a crucial component in the evolution of human cancers. With our limited knowledge of the molecular basis and timing of the initiation of altered methylation events in the stepwise progression of cancers, the biggest challenge we currently face is to identify novel biomarkers and technologies for the timely screening of patients carrying such alterations. One such strategy would be to develop tests for the detection of fecal DNA methylation patterns that will improve the sensitivity of noninvasive screening tests for colorectal neoplasia, and moreover, will decrease both mortality and the incremental costs of treating colorectal cancers

An Optimized Pentaplex PCR for Detecting DNA Mismatch Repair-Deficient Colorectal Cancers

Microsatellite instability (MSI) is used to screen colorectal cancers (CRC) for Lynch Syndrome, and to predict outcome and response to treatment. The current technique for measuring MSI requires DNA from normal and neoplastic tissues, and fails to identify tumors with specific DNA mismatch repair (MMR) defects. We tested a panel of five quasi-monomorphic mononucleotide repeat markers amplified in a single multiplex PCR reaction (pentaplex PCR) to detect MSI.We investigated a cohort of 213 CRC patients, comprised of 114 MMR-deficient and 99 MMR-proficient tumors. Immunohistochemical (IHC) analysis evaluated the expression of MLH1, MSH2, PMS2 and MSH6. MSI status was defined by differences in the quasi-monomorphic variation range (QMVR) from a pool of normal DNA samples, and measuring differences in allele lengths in tumor DNA.Amplification of 426 normal alleles allowed optimization of the QMVR at each marker, and eliminated the requirement for matched reference DNA to define MSI in each sample. Using ≥2/5 unstable markers as the criteria for MSI resulted in a sensitivity of 95.6% (95% CI = 90.1–98.1%) and a positive predictive value of 100% (95% CI = 96.6%–100%). Detection of MSH6-deficiency was limited using all techniques. Data analysis with a three-marker panel (BAT26, NR21 and NR27) was comparable in sensitivity (97.4%) and positive predictive value (96.5%) to the five marker panel. Both approaches were superior to the standard approach to measuring MSI.An optimized pentaplex (or triplex) PCR offers a facile, robust, very inexpensive, highly sensitive, and specific assay for the identification of MSI in CRC

ブラシ状カーボンナノチューブの合成プロセスに関する研究

学位授与大学: Osaka Prefecture University(大阪府立大学), 学位の種類: 博士(工学), 学位記番号: 論工第1227号, 学位授与年月日: 2009-09-30, 指導教員: 秋田 成司

Methylation profiles of genes utilizing newly developed CpG island methylation microarray on colorectal cancer patients

Aberrant methylation of DNA has been shown to play an important role in a variety of human cancers, developmental disorders and aging. Hence, aberrant methylation patterns in genes can be a molecular marker for such conditions. Therefore, a reliable but uncomplicated method to detect DNA methylation is preferred, not merely for research purposes but for daily clinical practice. To achieve these aims, we have established a precise system to identify DNA methylation patterns based on an oligonucleotide microarray technology. Our microarray method has an advantage over conventional methods and is unique because it allows the precise measurement of the methylation patterns within a target region. Our simple signal detection system depends on using an avidin–biotinylated peroxidase complex and does not require an expensive laser scanner or hazardous radioisotope. In this study, we applied our technique to detect promoter methylation status of O(6)-methylguanine-DNA methyltransferase (MGMT) gene. Our easy-handling technology provided reproducible and precise measurement of methylated CpGs in MGMT promoter and, thus, our method may bring about a potential evolution in the handling of a variety of high-throughput DNA methylation analyses for clinical purposes

Acute Bowel Injury due to Cryoablation for Renal Cell Carcinoma: Correlated Radiologic and Pathologic Findings

An 87-year-old Japanese man underwent percutaneous cryoablation (PCA) therapy for his renal cell tumor. We displaced the colon from the tumor using hydrodissection. Computed tomography (CT) immediately after PCA was indicative of iceball extension to the colon wall, and a discontinuous enhancement of the colon wall was observed. We therefore performed an emergency surgery. On laparotomy, we observed a dark-purple area on the affected area of the colon, and the resected specimen showed focal, deep ulceration on the mucosal surface. Photomicrography revealed mucosal necrosis, submucosal hemorrhage, and necrotic foci in the muscularis propria, corresponding to the discontinuous colon wall enhancement on CT and the deep ulceration and dark-purple area on laparotomy. He recovered from surgery and was discharged without any complications

Moderation of Negative Oxygen Effects by Small Yttrium Addition to Low Activation Vanadium Alloys

In order to improve irradiation embrittlement of vanadium alloys for fusion reactors, yttrium (Y) has been added reducing the interstitial oxygen impurity. However Y addition can also degrade high-temperature strength, because Y could scavenge oxygen in solid solution, which is a strong hardening agent in vanadium alloys. In this study, the effect of Y addition and oxygen level on the mechanical properties was investigated from the view points of both the high-temperature strength and low temperature ductility. Y addition was suggested to moderate the hardening and embrittlement induced by oxygen impurity sustaining the high-temperature strength within an acceptable level