1,721,050 research outputs found
Loss of Smad4 expression predicts liver metastasis in human colorectal cancer
No full textDistant metastases represent the major cause of death after curative surgery of colorectal cancer. The aim of this study was to evaluate the role of Smad4 and KRAS genetic alterations in colorectal metastases taking into account both the site (hepatic versus extrahepatic) and the time (synchronous versus metachronous) of recurrence. We examined the immunohistochemical expression of Smad4 and frequency of KRAS mutation in primary colorectal tumors and in their corresponding metastatic tissues. Loss of Smad4 expression was noted in 37% (26/71) of the primary tumors and the corresponding metastases. Absence of Smad4 protein was more frequently observed in hepatic metastases, whether they were metachronous or synchronous, than in extrahepatic metastases (p<0.005). The frequency of KRAS mutations was high in the synchronous and extrahepatic metachronous metastases (68-80%), but was significantly lower in the hepatic metachronous metastases (11%). Our results indicate that absence of Smad4 expression correlated significantly with liver metastases regardless of the time of their occurrence and represents a promising new biomarker to predict liver metastasis in colorectal cancer patients. Therefore, this group of patients could benefit from a specific and appropriate pre- and/or post-operative therapy
Selection of patients with germline MLH1 mutated Lynch syndrome by determination of MLH1 methylation and BRAF mutation.
No full textLynch syndrome is one of the most common hereditary colorectal cancer (CRC) syndrome and is caused by germline mutations of MLH1, MSH2 and more rarely MSH6, PMS2, MLH3 genes. Whereas the absence of MSH2 protein is predictive of Lynch syndrome, it is not the case for the absence of MLH1 protein. The purpose of this study was to develop a sensitive and cost effective algorithm to select Lynch syndrome cases among patients with MLH1 immunohistochemical silencing. Eleven sporadic CRC and 16 Lynch syndrome cases with MLH1 protein abnormalities were selected. The BRAF c.1799T> A mutation (p.Val600Glu) was analyzed by direct sequencing after PCR amplification of exon 15. Methylation of MLH1 promoter was determined by Methylation-Sensitive Single-Strand Conformation Analysis. In patients with Lynch syndrome, there was no BRAF mutation and only one case showed MLH1 methylation (6%). In sporadic CRC, all cases were MLH1 methylated (100%) and 8 out of 11 cases carried the above BRAF mutation (73%) whereas only 3 cases were BRAF wild type (27%). We propose the following algorithm: (1) no further molecular analysis should be performed for CRC exhibiting MLH1 methylation and BRAF mutation, and these cases should be considered as sporadic CRC; (2) CRC with unmethylated MLH1 and negative for BRAF mutation should be considered as Lynch syndrome; and (3) only a small fraction of CRC with MLH1 promoter methylation but negative for BRAF mutation should be true Lynch syndrome patients. These potentially Lynch syndrome patients should be offered genetic counselling before searching for MLH1 gene mutations
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Potentiel métastatique des adénomes coliques cancérisés
No full textIntroduction :¦Alors que le risque de métastases ganglionnaires est absent pour les adénomes coliques avec dysplasie de haut degré ou adénocarcinome intramuqueux limités à la muqueuse, ce risque existe à priori pour les adénomes avec transformation adénocarcinomateuse se définissant par l'envahissement de la sous-muqueuse (pT1). Néanmoins l'importance de leur potentiel à développer des métastases reste difficile à estimer posant un réel problème pour leur prise en charge. A ce jour, près de la moitié des adénocarcinomes débutants diagnostiqués sur des polypectomies est traitée par une résection colique chirurgicale complémentaire avec un curage ganglionnaire.¦Le but de cette étude est de quantifier le risque de développement de métastases ganglionnaires pour les adénocarcinomes pT1 et de définir les critères histologiques et macroscopiques utiles pour l'évaluation de ce risque.¦Méthode :¦Il s'agit d'une revue rétrospective de 32 cas d'adénocarcinomes colo-rectaux débutants chez 31 patients et recensés entre 2000 et 2010 à l'institut de pathologie du CHUV. Pour chaque tumeur nous avons procédé à une analyse macroscopique et histologique détaillée et nous l'avons corrélée à la rechercher de métastases ou de récidives lors du suivi. Enfin nous avons comparés nos résultats à une analyse de la littérature.¦Résultats et conclusion :¦Un seul adénocarcinome parmi les 32 adénocarcinomes recensés (3.13%) a présenté une métastase ganglionnaire avec 1 ganglion métastatique sur 21 ganglions prélevés. Aucune récidive n'a été mise en évidence lors du suivi des 32 adénocarcinomes. Ces résultats sont beaucoup plus optimistes que ceux de la littérature permettant de penser que la majorité de ces tumeurs peuvent être traités par polypectomie seule avec suivi endoscopique.¦Selon la littérature, les paramètres les plus significatifs pour la prédiction du risque métastatique sont un grade 3, une clearance inférieure à 2mm, un budding marqué (petits bourgeonnements de cellules tumorales éloignées de la masse tumorale principale), l'invasion du 3ème tiers de la sous-muqueuse (sm3) et l'invasion vasculaire. Notre étude confirme l'importance de la mise en évidence d'invasion lymphatique et montre un intérêt probable de la réaction de budding et de la taille du front d'invasion tumoral dans la prédiction du risque de développement de métastases ganglionnaire
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