1,720,981 research outputs found
A Risk Model to Predict 90-Day Mortality among Patients Undergoing Hepatic Resection
No full textBACKGROUND: Reliable criteria to predict mortality after hepatectomy remain poorly defined. We sought to identify factors associated with 90-day mortality, as well as validate the "50-50" and peak bilirubin of >7 mg/dL prediction rules for mortality after liver resection. In addition, we propose a novel integer-based score for 90-day mortality using a large cohort of patients. STUDY DESIGN: Data from 2,056 patients who underwent liver resection at 2 major hepatobiliary centers between 1990 and 2011 were identified. Perioperative laboratory data, as well as surgical and postoperative details, were analyzed to identify factors associated with liver-related 90-day death. RESULTS: Indications for liver resection included colorectal metastasis (39%), hepatocellular carcinoma (19%), benign mass (17%), or noncolorectal metastasis (14%). Most patients had normal underlying liver parenchyma (71%) and resection involved >= 3 segments (36%). Overall morbidity and mortality were 19% and 2%, respectively. Only 1 patient fulfilled the 50-50 criteria; this patient survived and was discharged on day 8. Twenty patients had a peak bilirubin concentration >7 mg/dL and 5 died within 90 days; the sensitivity and specificity of the > 7-mg/dL rule were 25% and 99.3%, respectively, but overall accuracy was poor (area under the curve 0.574). Factors associated with 90-day mortality included international normalized ratio (odds ratio = 11.87), bilirubin (odds ratio = 1.16), and serum creatinine (odds ratio = 1.87) on postoperative day 3, as well as grade of postoperative complications (odds ratio = 5.08; all p = 11 points had a sensitivity and specificity of 83.3% and 98.8%, respectively. CONCLUSIONS: The 50-50 and bilirubin > 7-mg/dL rules were not accurate in predicting 90-day mortality. Rather, a composite integer-based risk score based on postoperative day 3 international normalized ratio, bilirubin, creatinine, and complication grade more accurately predicted 90-day mortality after hepatectomy. (J Am Coll Surg 2013; 216: 1049-1056. (C) 2013 by the American College of Surgeons
Erratum:Counting alleles reveals a connection between chromosome 18q loss and vascular invasion
No full textEffect of KRAS Mutation on Long-term Outcomes of Patients undergoing Hepatic Resection for Colorectal Liver Metastases
No full textTo investigate the prognostic value of KRAS in a large cohort of patients undergoing liver resection for colorectal liver metastases (CRLM). Between 2003 and 2013, 334 patients underwent hepatic resection for CRLM at Johns Hopkins Hospital and met the inclusion criteria. Clinicopathologic characteristics, perioperative details, and outcomes were stratified by KRAS status-mutant KRAS (mtKRAS) versus wild-type KRAS (wtKRAS)-and analyzed. mtKRAS was identified in 115 (34.4 %) patients. At a median follow-up of 28.2 months, recurrence was observed in 59 (51.3 %) patients with mtKRAS and 117 (53.4 %) patients with wtKRAS (P = 0.79); there was no difference in the pattern of recurrence (liver: mtKRAS 39.0 % vs. wtKRAS 52.1 %; lung: mtKRAS 55.6 % vs. wtKRAS 64.3 %; both P > 0.05). Although 5-year log-rank overall survival (OS) was comparable among mtKRAS (41.6 %) vs. wtKRAS (48.5 %), on multivariable Cox survival analysis and after adjusting for known predictors of OS mtKRAS was associated with worse OS (hazard ratio 1.65; 95 % confidence interval 1.07-2.54; P = 0.02). Among patients who experienced a recurrence, 5-year OS was worse among those patients who had mtKRAS (mtKRAS 28.1 % vs. wtKRAS 44.5 %; P = 0.004). After controlling for tumor factors and receipt of chemotherapy, mtKRAS status remained independently associated with a worse outcome among patients who experienced recurrence (hazard ratio 2.07; 95 % confidence interval 1.31-3.27; P = 0.002). mtKRAS was noted in one-third of patients with CRLM. Although KRAS status did not affect the pattern of recurrence and recurrence-free survival, mtKRAS was an independent predictor of worse OS. The effect was more pronounced among patients who experienced a recurrence after resection of CRLM
Association Between Specific Mutations in KRAS Codon 12 and Colorectal Liver Metastasis
No full textIMPORTANCE Currently, one of the most commonly available biomarkers in the treatment of patients with colorectal liver metastases (CRLM) is the Kirsten rat sarcoma viral oncogene homolog (KRAS); however, the prognostic implications of specific mutations of the KRAS gene are still not well defined. OBJECTIVE To investigate the prognostic impact of specific KRAS mutations on patients undergoing liver resection for CRLM. DESIGN, SETTING, AND PARTICIPANTS This retrospective single-center study was conducted from January 1, 2003, to December 31, 2013. Data about specific KRAS mutations for 331 patients who underwent hepatic resection for CRLM at Johns Hopkins Hospital between 2003 and 2013 were analyzed. Clinicopathological characteristics, perioperative details, and outcomes were stratified by specific KRAS mutation at codons 12 and 13. INTERVENTION Resection of CRLM. MAIN OUTCOMES AND MEASURES Overall survival (OS) and recurrence-free survival. RESULTS A mutated KRAS (mtKRAS) was identified in 91 patients (27.5%). At a median follow-up of 27.4 months, recurrence was observed in 48 patients (52.7%) with mtKRAS and 130 patients (54.2%) with wild-type KRAS (wtKRAS) (P = .82). Median and 5-year survival among patients with mtKRAS was 32.4 months and 32.7%, respectively, vs 58.5 months and 46.9%, respectively, for patients with wtKRAS (P = .02). Patients with KRAS codon 12 mutations had worse OS (hazard ratio [HR], 1.54; 95% CI, 1.05-2.27; P = .03) vs those with wtKRAS, whereas a KRAS codon 13 mutation was not associated with prognosis (HR, 1.47; 95% CI, 0.83-2.62; P = .19). Among the 6 most common mutations in codons 12 and 13, only G12V (HR, 1.78; 95% CI, 1.00-3.17; P = .05) and G12S (HR, 3.33; 95% CI, 1.22-9.10; P = .02) were associated with worse OS compared with patients with wtKRAS (both P < .05). Among patients who recurred, G12V (HR, 2.96; 95% CI, 1.32-6.61; P = .01), G12C (HR, 6.74; 95% CI, 2.05-22.2; P = .002), and G12S mutations (HR, 4.91; 95% CI, 1.52-15.8; P = .01) were associated with worse OS (both P < .05). CONCLUSIONS AND RELEVANCE G12V and G12S mutations of codon 12 were independent prognostic factors of worse OS. Among patients who recurred after resection of CRLM, G12V, G12C, and G12S mutations were associated with worse OS. Information on specific KRAS mutations may help individualize therapeutic and surveillance strategies for patients with resected CRLM
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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