Seiji Tachiiri

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The Rad51 protein, a eukaryotic homologue of Escherichia coli RecA, plays a central role in both mitotic and meiotic homologous DNA recombination (HR) in Saccharomyces cerevisiae and is essential for the proliferation of vertebrate cells. Five vertebrate genes, RAD51B, -C, and -D and XRCC2 and -3, are implicated in HR on the basis of their sequence(More)
Yeast Rad52 DNA-repair mutants exhibit pronounced radiation sensitivity and a defect in homologous re combination (HR), whereas vertebrate cells lacking Rad52 exhibit a nearly normal phenotype. Bio chemical studies show that both yeast Rad52 and Rad55-57 (Rad51 paralogs) stimulate DNA-strand exchange mediated by Rad51. These findings raise the possibility(More)
PURPOSE To understand comprehensive transcriptional profile of normal human fibroblast in response to irradiation. METHODS AND MATERIALS To identify genes whose expression is influenced by gamma radiation, we used a cDNA microarray to analyze expression of 23,000 genes in normal human fibroblasts at 7 timepoints (1, 3, 6, 12, 24, 48, and 72 hours) after 5(More)
PURPOSE Severe acute radiation dermatitis is observed in approximately 5% to 10% of patients who receive whole-breast radiotherapy. Several factors, including treatment-related and patient-oriented factors, are involved in susceptibility to severe dermatitis. Genetic factors are also thought to be related to a patient's susceptibility to severe dermatitis.(More)
Yeast Sir2 is a nicotinamide adenine dinucleotide (NAD)-dependent histone deacetylase that plays a central role in transcriptional silencing, chromosomal stability, DNA damage response and aging. In mammals, Sir2-like genes constitute a seven-member family whose function is largely unknown. To investigate the role of the Sir2 family in vertebrates, we have(More)
This study evaluated patients for the influence of the dose rate and lung dose of fractionated total body irradiation (TBI) in preparation for allogeneic bone marrow transplantation (BMT) on the subsequent development of interstitial pneumonitis (IP). Sixty-six patients at our institute were treated with TBI followed by BMT. All of the patients received a(More)
Purpose: Topoisomerase inhibitors including camptothecin are being studied as potential radiosensitizers. CPT-11 is a derivative of camptothecin and is clinically available. In this study, we investigated the effects of SN-38 (an active metabolite of CPT-11) on four nonirradiated and irradiated murine fibroblast cell lines with different p53 statuses to(More)
Phosphatidylinositol 3-kinase (PI3-K) is a heterodimer of a regulatory subunit, p85, and a catalytic subunit, p110. A number of previous reports showed that PI3-K functions in diverse cellular phenomena such as cell proliferation, glucose catabolism, cell adhesion, and vesicle transport. It is also well known that a survival signal from the receptor(More)
Germline mutation of the BRCA2 gene causes a high risk of developing breast and ovarian cancer. Although the BRCA2 protein has been implicated in homologous recombination (HR) of DNA and in transcription, it is still unclear how mutation leads to tumorigenesis. We have identified a non-mammalian homologue of BRCA2 from chicken, which encodes a protein with(More)
To investigate the feasibility of image-based intracavitary brachytherapy (IBICBT) for uterine cervical cancer, we evaluated the dose-volume histograms (DVHs) for the tumor and organs at risk (OARs) and compared results from the IBICBT plan and the standard Manchester system (Manchester plan) in eight patients as a simulation experiment. We performed(More)