185 research outputs found

    A functional analysis of the DNA glycosylase activity of mouse MUTYH protein excising 2-hydroxyadenine opposite guanine in DNA

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    2-Hydroxy-2-deoxyadenosine triphosphate (2-OH-dATP), generated by the oxidation of dATP, can be misincorporated by DNA polymerases opposite guanine in template DNA during DNA replication, thus causing spontaneous mutagenesis. We demonstrated that mouse MUTYH (mMUTYH) has a DNA glycosylase activity excising not only adenine opposite 8-oxoguanine (8-oxoG) but also 2-hydroxyadenine (2-OH-A) opposite guanine, using purified recombinant thioredoxin-mMUTYH fusion protein. mMUTYH formed a stable complex with duplex oligonucleotides containing an adenine:8-oxoG pair, but the binding of mMUTYH to oligonucleotides containing a 2-OH-A:guanine pair was barely detectable, thus suggesting that mMUTYH recognizes and interacts with these two substrates in a different manner which may reflect the difference in the base excision repair process for each substrate. Mutant mMUTYH with G365D amino acid substitution, corresponding to a G382D germline mutation of human MUTYH found in familial adenomatous polyposis patients, almost completely retained its DNA glycosylase activity excising adenine opposite 8-oxoG; however, it possessed 1.5% of the wild-type activity excising 2-OH-A opposite guanine. Our results imply that the reduced repair capacity of the mutant hMUTYH(G382D), which inefficiently excises 2-OH-A opposite guanine, results in an increased occurrence of somatic G:C to T:A transversion mutations in the APC gene as well as tumorigenesis in the colon

    MicroRNA in Cervical Cancer: OncomiRs and Tumor Suppressor miRs in Diagnosis and Treatment

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    Cervical cancer is a female-specific disease with a high incidence and mortality. MicroRNAs (miRNAs) are implicated in posttranscriptional regulation of gene expression and in the pathogenic mechanisms of cancer, suggesting their importance in diagnosis and treatment. miRNAs may have roles in the pathogenesis of cervical cancer based on the increases or decreases in several specific miRNAs found in patients with this disease. The miRNAs implicated in cervical cancer are miR-21, miR-126, and miR-143, and clinical application of these miRNAs for diagnosis and treatment is under investigation. Methods for diagnosis of cervical cancer include analysis of changes in the levels of specific miRNAs in serum and determination of aberrant hypermethylation of miRNAs. Supplementation of miR-143 or inhibition of miR-21 activity in vivo may be therapeutic strategy for cervical cancer. Previous approaches to development of siRNA as a drug have provided information for establishment of therapy based on these approaches, and an anti-miR-21 inhibitor has been developed. miRNAs also have effects on drug resistance and may be useful in combination therapy with other drugs

    ホスピス トクシマ ニオケル マッキ ガン カンジャ ノ ボウシュヨウセイ シンケイ ショウコウグン ノ ハッショウ ヒンド ト ソノ リンショウテキ イギ

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    Neurological complications in advanced cancer occur frequently and therefore an adequate neurological assessment must always be part of patient evaluation in hospice palliative care. Paraneoplastic neurological syndromes are rare, probably affecting less than 1 per cent of patients with cancer, even if the most commonly associated neoplasms, such as small-cell lung cancer and ovarian cancer are considered. Neurological complications were studied in 127 inpatients with advanced cancers. Neurological complications were seen in up to 40 per cent of the patients. The most frequent symptom was derilium, followed in order to lethargy, paraplegia, depression, dementia, hemiplegia, restlessness, aphasia, stupor, facial palsy, recurrent laryngeal nerve palsy, convulsion, and myastenia. Those symptoms were seen in patients in hepatic encephalitis(12), metastatic brain tumor(9), metastatic spinal cord injury(8), depression(4), paraneoplastic syndrome(4), hypercalcemia(2), senile dementia(2), peripheral neuritis(2), and cerebral infarction(2). Of the four patients with paraneoplastic syndrome, one patient had both anti-Hu antibody and anti-VGCC antibody and two patients had anti-neuronal nuclear antibodies. These results indicate that paraneoplastic neurological syndromes are associated more than 1 per cent of patients with advanced cancer

    Diversity of Melissococcus plutonius from Honeybee Larvae in Japan and Experimental Reproduction of European Foulbrood with Cultured Atypical Isolates

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    European foulbrood (EFB) is an important infectious disease of honeybee larvae, but its pathogenic mechanisms are still poorly understood. The causative agent, Melissococcus plutonius, is a fastidious organism, and microaerophilic to anaerobic conditions and the addition of potassium phosphate to culture media are required for growth. Although M. plutonius is believed to be remarkably homologous, in addition to M. plutonius isolates with typical cultural characteristics, M. plutonius-like organisms, with characteristics seemingly different from those of typical M. plutonius, have often been isolated from diseased larvae with clinical signs of EFB in Japan. Cultural and biochemical characterization of 14 M. plutonius and 19 M. plutonius-like strain/isolates revealed that, unlike typical M. plutonius strain/isolates, M. plutonius-like isolates were not fastidious, and the addition of potassium phosphate was not required for normal growth. Moreover, only M. plutonius-like isolates, but not typical M. plutonius strain/isolates, grew anaerobically on sodium phosphate-supplemented medium and aerobically on some potassium salt-supplemented media, were positive for β-glucosidase activity, hydrolyzed esculin, and produced acid from L-arabinose, D-cellobiose, and salicin. Despite the phenotypic differences, 16S rRNA gene sequence analysis and DNA-DNA hybridization demonstrated that M. plutonius-like organisms were taxonomically identical to M. plutonius. However, by pulsed-field gel electrophoresis analysis, these typical and atypical (M. plutonius-like) isolates were separately grouped into two genetically distinct clusters. Although M. plutonius is known to lose virulence quickly when cultured artificially, experimental infection of representative isolates showed that atypical M. plutonius maintained the ability to cause EFB in honeybee larvae even after cultured in vitro in laboratory media. Because the rapid decrease of virulence in cultured M. plutonius was a major impediment to elucidation of the pathogenesis of EFB, atypical M. plutonius discovered in this study will be a breakthrough in EFB research
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