1,721,005 research outputs found
Current Concepts in (68)Ga-DOTATATE Imaging of Neuroendocrine Neoplasms: Interpretation, Biodistribution, Dosimetry, and Molecular Strategies
No full text(68)Ga-DOTATATE PET/CT provides information on the location of somatostatin receptor-expressing tumors. Integrating this imaging data effectively in patient care requires the clinical history; the histopathology and biomarker information; and the grade, stage, and prior imaging results. Previous therapies and technical aspects of the study should be considered, given their ability to alter the interpretation of the images. This includes physiologic biodistribution of the radiotracer, as well as conditions that engender false-positive results. This article provides a guide to the performance and interpretation of (68)Ga-DOTATATE PET/CT and describes its role in the diagnostic algorithm of neuroendocrine neoplasms and its overall utility in their management
GNA15 expression in small intestinal neuroendocrine neoplasia: functional and signalling pathway analyses
No full textGastroenteropancreatic neuroendocrine neoplasia (GEP-NEN) comprises a heterogeneous group of tumours that exhibit widely divergent biological behaviour. The identification of new targetable GPCR-pathways involved in regulating cell function could help to identify new therapeutic strategies. We assessed the function of a haematopoietic stem cell heterotrimeric G-protein, Gα15, in gut neuroendocrine cell models and examined the clinical implications of its over expression. Functional assays were undertaken to define the role of GNA15 in the small intestinal NEN cell line KRJ-I and in clinical samples from small intestinal NENs using quantitative polymerase chain reaction, western blot, proliferation and apoptosis assays, immunoprecipitation, immunohistochemistry (IHC) and automated quantitative analysis (AQUA). GNA15 was not expressed in normal neuroendocrine cells but was overexpressed in GEP-NEN cell lines. In KRJ-I cells, decreased expression of GNA15 was associated with inhibition of proliferation, activation of apoptosis and differential effects on pro-proliferative ERK, NFκB and Akt pathway signalling. Moreover, Gα15 was demonstrated to couple to the ß1 adrenergic receptor and modulated proliferative signals through this GPCR. Transcript and protein levels of GNA15 were significantly elevated in primary and metastatic tumours compared to normal mucosa and were particularly increased in low Ki-67 expressing tumours. IHC and AQUA revealed that a higher Gα15 expression was associated with a poorer survival. GNA15 may have a pathobiological role in SI-NENs. Targeting this signalling mediator could provide an opportunity for the development of new therapeutic strategies for this tumour type
Peptide Receptor Radionuclide Therapy for Advanced Neuroendocrine Tumors
No full textNo abstract availabl
Treatment of advanced gastroenteropancreatic neuroendocrine neoplasia, are we on the way to personalised medicine?
No full textGastroenteropancreatic neuroendocrine neoplasia (GEPNEN) comprises clinically as well as prognostically diverse tumour entities often diagnosed at late stage. Current classification provides a uniform terminology and a Ki67-based grading system, thereby facilitating management. Advances in the study of genomic and epigenetic landscapes have amplified knowledge of tumour biology and enhanced identification of prognostic and potentially predictive treatment subgroups. Translation of this genomic and mechanistic biology into advanced GEPNEN management is limited. 'Targeted' treatments such as somatostatin analogues, peptide receptor radiotherapy, tyrosine kinase inhibitors and mammalian target of rapamycin inhibitors are treatment options but predictive tools are lacking. The inability to identify clonal heterogeneity and define critical oncoregulatory pathways prior to therapy, restrict therapeutic efficacy as does the inability to monitor disease status in real time. Chemotherapy in the poor prognosis NEN G3 group, though associated with acceptable response rates, only leads to short-term tumour control and their molecular biology requires delineation to provide new and more specific treatment options.The future requires an exploration of the NEN tumour genome, its microenvironment and an identification of critical oncologic checkpoints for precise drug targeting. In the advance to personalised medical treatment of patients with GEPNEN, clinical trials need to be based on mechanistic and multidimensional characterisation of each tumour in order to identify the therapeutic agent effective for the individual tumour.This review surveys advances in NEN research and delineates the current status of translation with a view to laying the basis for a genome-based personalised medicine management of advanced GEPNEN
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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