1,720,993 research outputs found
Infrahepatic inferior vena cava clamping for reduction of central venous pressure and blood loss during hepatic resection: a randomized controlled trial
No full textOne-millimeter cancer-free margin is curative for colorectal liver metastases: a propensity score case-match approach
No full textOBJECTIVE: To investigate the influence of clear surgical resection margin width on disease recurrence rate after intentionally curative resection of colorectal liver metastases.BACKGROUND: There is consensus that a histological positive resection margin is a predictor of disease recurrence after resection of colorectal liver metastases. The dispute, however, over the width of cancer-free resection margin required is ongoing.METHODS: Analysis of observational prospectively collected data for 2715 patients who underwent primary resection of colorectal liver metastases from 2 major hepatobiliary units in the United Kingdom. Histological cancer-free resection margin was classified as positive (if cancer cells present at less than 1 mm from the resection margin) or negative (if the distance between the cancer and the margin is 1 mm or more). The negative margin was further classified according to the distance from the tumor in millimeters. Predictors of disease-free survival were analyzed in univariate and multivariate analyses. A case-match analysis by a propensity score method was undertaken to reduce bias.RESULTS: A 1-mm cancer-free resection margin was sufficient to achieve 33% 5-year overall disease-free survival. Extra margin width did not add disease-free survival advantage (P > 0.05). After the propensity case-match analysis, there is no statistical difference in disease-free survival between patients with negative narrow and wider margin clearance [hazard ratio (HR) 1.0; 95% (confidence interval) CI: 0.9-1.2; P = 0.579 at 5-mm cutoff and HR 1.1; 95% CI: 0.96-1.3; P = 0.149 at 10-mm cutoff]. Patients with extrahepatic disease and positive lymph node primary tumor did not have disease-free survival advantage despite surgical margin clearance (9 months for <1-mm vs 12 months for ≥1-mm margin clearance; P = 0.062).CONCLUSION: One-mm cancer-free resection margin achieved in patients with colorectal liver metastases should now be considered the standard of care.</p
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
Large hepatocellular carcinoma: time to stop preoperative biopsy
No full textBackground: Western countries, hepatocellular carcinoma (HCC) often presents at a large size, which is seen as a contraindication to transplantation and often resection. Although diagnosis by imaging and ?-fetoprotein is usually straightforward, nonspecialist units continue to use biopsy to prove the diagnosis before transfer for specialist surgical opinion. We have looked at the impact of this on our practice.Study Design: We retrospectively analyzed all large HCCs resected in our unit during the last 12 years. Survival data were calculated according to size and univariate and multivariate analyses were carried out to determine impact of preoperative, operative, and histologic factors affecting outcomes.Results: We identified 85 large HCCs (> 3 cm) and classified 42 as giant (> 10 cm). Overall survival at 1, 3, and 5 years was 76%, 54%, and 51%. Size did not influence survival, although more complex surgical techniques were required for giant tumors. Predictors of poorer disease-free survival were positive resection margin (p < 0.001), multiple tumors (p = 0.003), macroscopic vascular invasion (p = 0.015), and preoperative lesion biopsy (p = 0.027).Conclusions: Our data shows excellent outcomes after resection for large HCC. This supports the management of such patients in large-volume units that are fully equipped and experienced in the management of these patients. Preoperative biopsy should be avoided, as this unnecessary maneuver appears to have worsened our longterm results.<br/
Hepatic resection for colorectal metastasis: impact of tumour size
No full textBACKGROUND: Many colorectal liver metastasis patients are denied surgical resection on the basis of tumour size. The aim of this study was to explore the impact of metastasis size on modern liver resection.METHODS: Using a prospectively collected database, this was a retrospective analysis of 484 consecutive patients who underwent liver resection for colorectal liver metastases between 1993 and 2003. The cohort was divided into two groups: smaller metastases (< 8 cm) and larger metastases (> or = 8 cm). Those with larger metastases were then further stratified into big metastases (8-12 cm) and giant metastases (> 12 cm). Demographic, pathological, surgical technique and outcome data were compared between the groups.RESULTS: There were 88 (18%) patients with metastases measuring 8 cm or larger. There was an association between higher carcinoembryonic antigen (CEA) and cancer antigen (CA) 19-9 levels and larger metastases. The actuarial 5-year survival for patients with larger metastases was 38% compared with 42% for smaller metastases (not statistically significant). Patients with giant metastases had poorer overall and disease-free survival (both nonsignificant) compared with those with big metastases: 29% and 28% at 5 years, respectively.CONCLUSION: Patients with colorectal liver metastasis greater than 8 cm and up to 12 cm in size should not be treated differently from those with smaller lesions.</p
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