1,720,965 research outputs found

    Mutation analysis of candidate genes in melanoma-prone families: evidence of different pathogenetic mechanisms at chromosome 9P21

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    Putative tumour suppressor genes CDKN2A and CDKN2B (on chromosome 9p21) and CDKN2A-interacting cell growth regulatory genes CDK4 and Id-1 have been demonstrated to be involved in the pathogenesis of malignant melanoma (MM). Mutation analysis of these candidate genes was performed in MM families from southern Italy with three or more affected members or two affected members and one or more relative with histologically diagnosed atypical naevus. Two CDKN2A mutations, Arg24Pro and 1-292 G>A, were observed in two (15%) families; except for CDKN2A and Id-1 polymorphisms, no sequence variations were detected in the remaining genes. Screening among 119 sporadic MM cases revealed two additional CDKN2A mutations at very low prevalences. Identification of a large shared haplotype at 9p21 in some MM families negative for CDKN germline mutations suggests that other CDKN-inactivating mechanisms may be responsible for MM predisposition or, alternatively, additional susceptibility gene(s) may be present on chromosome 9p21. Fluorescence in situ hybridization analysis of a subset of MM tissue sections seemed to indicate that the D9S171 locus may be involved in MM pathogenesis. (C) 2003 Lippincott Williams Wilkins

    Detection of occult melanoma cells in paraffin-embedded histologically negative sentinel lymph nodes using a reverse transcriptase polymerase chain reaction assay

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    Purpose: Detection of occult metastasis before the development of clinical disease could allow more accurate staging, appropriate follow-up procedures, and adjuvant therapies in patients with malignant melanoma (MM). The sentinel lymph node (SLN) has been proposed as a reliable predictor of metastatic disease in the lymphatic basin draining the primary melanoma. In this study, we screened both paraffin-embedded SLNs and peripheral-blood (PB) samples from MM patients at various stage of disease using a multimarker reverse transcriptase polymerase chain reaction (RT-PCR) assay. The prognostic significance of the presence of PCR-positive markers was also evaluated. Patients and Methods: Total RNA was obtained from paraffin-embedded SLN sections and PB samples of 75 MM patients. RT-PCR was performed using tyrosinase and MelanA/MART1 as melanoma-associated markers. Radiolabeled PCR products were analyzed on denaturing polyacrylamide gels. Results: Good sensitivity of the RT-PCR assay on archival tissues was demonstrated after comparison of RT-PCR results on frozen and paraffin-embedded SLNs from 16 MM patients. Significant correlation between the disease stage and marker expression in both PB and SLN samples was observed; the highest value was for patients who were positive for both markers in SLN (P =.006). Progression of disease was significantly associated with the total number of PCR-positive markers in both PB (P =.034) and SLN (P =.001) samples. Conclusion: Although sensitivity is lowered by the use of paraffin-embedded specimens, our data indicate that RT-PCR analysis of serial sections from archival SLNs may be helpful in improving detection of occult micrometastases, thus improving staging of patients with melanoma. J Clin Oncol 19:1437-1443. (C) 2001 by American Society of Clinical Oncology

    Going Beyond Counting First Authors in Author Co-citation Analysis

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    The present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed

    Variations on the Author

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    “Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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