41 research outputs found

    Radiation-induced cancer after radiotherapy for non-Hodgkin's lymphoma of the head and neck: a retrospective study

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    <p>Abstract</p> <p>Background</p> <p>survivors of non-Hodgkin's lymphoma (NHL) are well known to be at an increased risk of second malignancies. In this study, we evaluated the incidence and clinical features of head and neck cancer (HNC) occurring after radiotherapy (RT) for NHL.</p> <p>Materials and methods</p> <p>We investigated the clinical records of 322 patients who had received RT for early-stage NHL of the head and neck at our institute between 1952 and 2000.</p> <p>Results</p> <p>There were 4 patients with a second HNC developing in the irradiated field, consisting of 2 patients with gum cancer, 1 case with tongue cancer and 1 case with maxillary sinus cancer. The pathological diagnosis in all the 4 patients was squamous cell carcinoma (SCC). Two of the patients (one with gum cancer and one with maxillary sinus cancer) died of the second HNC, while the remaining 2 patients are still living at the time of writing after therapy for the second HNC, with neither recurrence of the second tumor nor relapse of the primary tumor. The ratio of the observed to the expected number (O/E ratio) of a second HNC was calculated to be 12.7 (95%CI, 4.07–35.0), and the absolute excess risk (AER) per 10,000 person-years was 13.3. The median interval between the RT and the diagnosis of the second HNC was 17.0 years (range, 8.7 to 22.7 years).</p> <p>Conlusion</p> <p>The risk of HNC significantly increased after RT for early-stage NHL. These results suggest that second HNC can be regarded as one of the late complications of RT for NHL of the head and neck.</p

    A mitochondrial mutator plasmid that causes senescence under dietary restricted conditions

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    BACKGROUND: Calorie or dietary restriction extends life span in a wide range of organisms including the filamentous fungus Podospora anserina. Under dietary restricted conditions, P. anserina isolates are several-fold longer lived. This is however not the case in isolates that carry one of the pAL2-1 homologous mitochondrial plasmids. RESULTS: We show that the pAL2-1 homologues act as 'insertional mutators' of the mitochondrial genome, which may explain their negative effect on life span extension. Sequencing revealed at least fourteen unique plasmid integration sites, of which twelve were located within the mitochondrial genome and two within copies of the plasmid itself. The plasmids were able to integrate in their entirety, via a non-homologous mode of recombination. Some of the integrated plasmid copies were truncated, which probably resulted from secondary, post-integrative, recombination processes. Integration sites were predominantly located within and surrounding the region containing the mitochondrial rDNA loci. CONCLUSION: We propose a model for the mechanism of integration, based on innate modes of mtDNA recombination, and discuss its possible link with the plasmid's negative effect on dietary restriction mediated life span extension

    Do Gender Diversity Recommendations in Corporate Governance Codes Matter? Evidence from Audit Committees

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    Motivated by two opposing views, the limited supply view and the discrimination view, we examine the impact of gender diversity guidelines on the strength of the association between the presence of female audit committee members and audit quality. The limited supply view predicts that the effect of female audit committee members on audit quality would decrease after the guidelines were issued because they increased the demand for women directors without a commensurate increase in the supply of qualified women directors. The discrimination view predicts this relation would increase after the guidelines were issued since some firms would have abandoned their suboptimal hiring practices that favored men over better qualified women, resulting in higher quality firm-director matches as opportunities for women increase. Consistent with the limited supply view, we find that the positive association between audit committee gender diversity and audit quality weakened after gender diversity guidelines were introduced in Australia
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