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  • 1995-1999  (3)
  • 1
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: We investigated the lethal and mutagenic effects of high linear energy transfer cosmic radiation on 11 strains of Escherichia coli, including DNA repair-deficient mutants, using the Radiation Monitoring Container and Dosimeter in the space shuttle ‘Endeavour’ as part of the ‘SL-J/FMPT’ space experiment, the ‘Fuwatto’ 92’ project. After the return to earth of the shuttle, we evaluated survival and mutations of samples in space and matched controls. The surviving fractions were determined by means of colony count on broth agar plates, and the mutation frequencies were estimated by appearance of arg+ revertants on minimal agar plates. The average of the total equivalent dose rate during this space flight was 0.202 mSv/day as measured by the plastic radiation detectors and the thermoluminescent dosimeters in the Radiation Monitoring Container and Dosimeter. The combined action of DNA polymerase and 3′→5′ exonuclease activities was found to make the greatest contribution to the repair of cosmic radiation-induced DNA damage, 5′→3′ exonuclease and recombination repair enzyme activities made a moderate contribution, whereas UV endonuclease activity was not involved in this DNA repair process.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of cancer research and clinical oncology 124 (1998), S. 503-510 
    ISSN: 1432-1335
    Keywords: Key words Bax ; Bcl-2 ; Radiotherapy ; Cervical carcinoma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: AbstractPurpose: The ratio of Bcl-2 to Bax expression determines survival or death following an apoptotic stimulus. In order to establish a new predictor of the outcome of treatment for human cervical carcinoma, we investigated the relationship between the expressions of the Bax and Bcl-2 proteins and the response to radiotherapy after the administration of 10.8 Gy. Methods: A total of 44 patients with histologically proven carcinoma of the uterine cervix, including three with recurrent cervical stump carcinomas, were treated with definitive radiotherapy. The presence of mutations in exons 5–8 of the p53 gene was analyzed by a single-strand conformation polymorphism analysis and DNA sequencing. Results: Forty patients were found to have wild-type p53, and the remaining four had mutant p53. The Bax and Bcl-2 protein expressions prior to radiotherapy did not correlate with response and survival. However, the Bax and Bcl-2 protein expressions after radiotherapy correlated with both response and survival. Bax-positive tumors showed significantly better responses than the Bax-negative tumors after 10.8 Gy radiation (P = 0.0002). In contrast, the Bcl-2-positive tumors showed significantly poorer responses than the Bcl-2-negative tumors after radiation (P = 0.002). Increased Bax expression after the 10.8 Gy radiotherapy was found to be correlated with good survival (P = 0.04). In contrast, increased Bcl-2 expression after such radiotherapy was correlated with poor survival (P = 0.002). Conclusion: The levels of Bax and Bcl-2 expression after 10.8 Gy radiotherapy are useful prognostic markers in patients with human cervical carcinoma.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1573-4919
    Keywords: hsp72 ; HSF ; phosphorylation ; H-7 ; protein kinase inhibitor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract We investigated the effects of a protein kinase (PK) inhibitor, H-7 (1-(5-isoquinolinesulfonyl)-2-methylpiperazine dihydrochloride), on the regulation of heat shock protein (hsp)72 gene expression in a human glioblastoma cell line (A-172) using a gel mobility-shift assay and Western blot analysis. Heat shock transcription factor 1 (HSF1) was phosphorylated immediately after heat treatment (44°C, 30 min) and the phosphorylation of HSF1 was suppressed by H-7. The increase in DNA binding ability of HSF1 to heat shock element (HSE) by heat shock was significantly suppressed by the addition of H-7 in a dose-dependent manner. Similarly, the accumulation of hsp72 by heat shock was suppressed by the addition of H-7 in a dose-dependent manner. Since H-7 is known to be a potent inhibitor of some PKs, especially calcium-dependent PK (PKC), cyclicAMP-dependent PK (PKA) and cyclicGMP-dependent PK (PKG), it is possible that the activation of HSF1 by phosphorylation and subsequent hsp72 gene expression are dependent on some of those PKs. The nature of H-7 as a non-specific inhibitor for PKs is discussed in relation to its availability for regulation of heat sensitivity of cells depending on cellular level of hsp72.
    Type of Medium: Electronic Resource
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