Yazar "Atha D.H." seçeneğine göre listele

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    Biomarkers used to detect genetic damage in tissue engineered skin
    (Springer Science and Business Media Deutschland GmbH, 2003) O'Connell C.; Barker P.E.; Marino M.; McAndrew P.; Atha D.H.; Jaruga P.; Birincio?lu M.
    [No abstract available]
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    Molecular biomarkers used to detect cellular/genetic damage in tissue-engineered skin
    (ASTM International, 2004) O'Connell C.; Barker P.E.; Marino M.; McAndrew P.; Atha D.H.; Jaruga P.; Birincioglu M.
    In this study, tissue-engineered skin (TestSkin II) was obtained, separated into its two cellular layers (epidermis and dermis) and DNA was extracted. The first biomarker tested consisted of screening for DNA point mutations in exons 5 and 6 of the TP53 gene, the most commonly mutated gene in skin cancer. To ensure the accuracy of the results, two measurement technologies that incorporate internal calibration standards were used. It was shown that tissue-engineered skin did not contain mutations in this gene at the level of sensitivity of SSCP-capillary electrophoresis and Denaturing High Performance Liquid Chromatography. Results were compared to control cells (neonatal fibroblasts and neonatal keratinocytes) and fibroblasts that were obtained from a 55-year-old and 96-year-old human donor. The second set of biomarkers tested looked at the loss of the Y-chromosome. Using Fluorescent In Situ Hybridization technology, no detectable loss of Y-chromosome was found in the tissue-engineered skin and neonatal control cells. Y-chromosome loss was found in the fibroblasts from the 96-year-old donor. Biomarkers such as TP53 mutations and chromosome loss can provide the basis for an international reference standard of cellular biomarkers that can aid in the development and safety of tissue engineered medical products.
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    Use of TP53 reference materials to validate mutations in clinical tissue specimens by single-strand conformational polymorphism analysis
    (2004) Sunar-Reeder B.; Atha D.H.; Aydemir S.; Reeder D.J.; Tully L.; Khan A.R.; O'Connell C.D.
    Background: As genetic information moves from basic research laboratories in to the clinical testing environment, there is a critical need for reliable reference materials for the quality assurance of genetic tests. A panel of 12 plasmid clones containing wild-type or point mutations within exons 5-9 have been developed as reference materials for the detection of TP53 mutations. Aim: The goal of this study was to validate the reference materials in providing quality assurance for the detection of TP53 mutations in clinical specimens. Methods: We studied 33 gynecological samples, 11 apparently normal samples and 22 malignant tumors of various origins. Mutations were identified using single-strand conformational polymorphism analysis with both slab gel and capillary electrophoresis. All DNA samples were amplified with fluorescently labeled PCR primers specific for exons 5-9 for mutation detection. Results: Of the 33 patient samples tested, mutations and polymorphisms were found in six specimens in three of the five exons scanned; no mutations were found in exons 7 or 9. Both a mutation and polymorphism were found in non-malignant specimens from the control group. The mutations were confirmed by DNA sequence analysis of the regions scanned. Conclusions: Mutations and polymorphisms were detected in the clinical samples. All of the mutations were silent except for one non-conservative mutation in exon 5, codon 181. This study demonstrates the usefulness of the National Institute of Standards and Technology (NIST) TP53 reference panel in TP53 mutation detection in clinical tissue specimens.