1,720,976 research outputs found
Osteonecrosis of the jaw during sorafenib therapy for hepatocellular carcinoma
No full textIntroduction: Sorafenib is an oral multiple tyrosine kinase inhibitor and is currently the only evidence-based treatment recommended for advanced hepatocellular carcinoma. We report a case of osteonecrosis of the jaw that occurred during sorafenib therapy in a patient with advanced hepatocellular carcinoma not treated with bisphosphonates or other antiangiogenic drugs. Methods: A systematic search in PubMed yielded some cases of osteonecrosis of the jaw in patients treated with antiangiogenic agents, alone or in combination with bisphosphonates, for metastatic renal cell carcinoma. The only case of osteonecrosis observed during sorafenib therapy not combined with other predisposing agents was described by Guillet et al. Results: A 74-year-old man diagnosed with hepatocellular carcinoma ensuing in hepatitis C virus infection, who was treated with sorafenib at a daily dose of 400 mg, developed osteonecrosis of the right mandibular body. The lesion was documented by a dental CT scan and surgical evaluation did not lead to an indication for curettage treatment. Sorafenib was discontinued because of the radiological and laboratory features of hepatocellular carcinoma progression and the high risk of jaw fracture. Conclusions: To our knowledge, this is the first description of osteonecrosis of the jaw detected in a cirrhotic patient on sorafenib therapy not combined with bisphosphonates
Is it time to extend criteria for hepatic resection in the treatment of hepatocellular carcinoma?
No full textLength time bias in surveillance for hepatocellular carcinoma and how to avoid it
No full textAim: Length time bias is a selection bias which can lead to an overestimation of survival of screening-detected cases caused by the relative excess of slower-growing tumors detected with respect to symptomatic cases. This leads to the incorrect perception that screening improves outcomes when it only selects tumors with a favorable biology. Data regarding this bias in surveillance for hepatocellular carcinoma (HCC) have never been provided. Methods: A semi-Markov model was developed to investigate this issue. An exponential tumor growth was applied. During its growth, tumor diagnosis "at surveillance appointments" was made when tumor attained a size equal to or above the size of tumors diagnosed in surveilled patients obtained from pertinent published reports, or "in-between appointments" (due to the development of symptoms) if tumor size attained the size of symptomatic diagnosis, derived from published reports; otherwise the tumor continued to grow until the time horizon had been reached. Tumor doubling time (DT) values were recorded according to the method of diagnosis. Results: In a theoretical cohort of 1000 patients submitted to semiannual surveillance, 72.5% will be diagnosed at a surveillance appointment and 18% because of symptom development, although under surveillance. Patients diagnosed with HCC at a surveillance appointment had a median tumor DT of 100 days (interquartile range, 68-143 days), whereas those diagnosed because of symptoms had a median DT of 42 days (interquartile range, 29-58 days) although under surveillance. Conclusion: The surveillance propensity to detect slower-growth tumors is relevant, and practical suggestions to minimize this bias in longitudinal studies are provided
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
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