1,720,957 research outputs found
Plasma chromogranin a response to octreotide test: prognostic value for clinical outcome in endocrine digestive tumors
No full textOBJECTIVES: Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) expressing somatostatin receptors may be treated with somatostatin analogs (SSAs). Selection criteria are a positive Octreoscan or a > 50% hormone level decrease after octreotide subcutaneous (s.c.) injection (octreotide test) (OT). Plasma chromogranin A (CgA) is the best general GEP-NET marker, but data on CgA response to OT are scanty. Thus, we evaluated whether plasma CgA response to OT could predict the clinical response to SSAs.
METHODS: At diagnosis, 38 GEP-NET patients received octreotide 200 mu g s.c., with plasma CgA determination at 0, 3, and 6 h. Long-term SSA treatment was then given by monitoring symptomatic, biochemical, and objective responses, and survival.
RESULTS: Basal plasma CgA levels were significantly higher in patients with functioning than non-functioning tumors (median (range): 220 (18-2,230) vs. 46 (25-8,610) U/l, P = 0.03) and in those with than without metastases (171 (18-8,610) vs. 43 (28-220) U/l, P = 0.04). CgA levels significantly correlated with WHO classification, clinical TNM staging, and Ki-67 proliferative index. After OT, CgA levels decreased from 146 (18-8,610) to 61 (10-8,535) U/l (basal and nadir values), P < 0.001. In patients responsive to OT, a successful objective response occurred in 21/31 patients (68%). Successful symptomatic response occurred in 13/18 patients (72%), biochemical response in 25/31 (81%), and objective response in 21/31 (68%). In the remaining seven unresponsive cases, with CgA decrement < 30%, disease progressed to death in six (86%). Median survival from enrollment was 48 months (6-138) in responsive and 6 (6-30) in unresponsive patients (P = 0.0005).
CONCLUSIONS: In GEP-NETs, plasma CgA is a reliable marker, and a > 30% decrease after OT has a relevant prognostic meaning allowing the identification of the subgroup of patients most likely to be responsive to chronic SSAs
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
Iron overload impairs the migratory ability of a model of immature and migratory GnRH neurons
No full textIron represents a micronutrient for cellular metabolism and aerobic respiration, and is essential for proper brain development in the fetal and early neonatal period. However, excess iron produces toxic build-up via free radical formation. In thalassaemic and juvenile hemochromatosis patients with pubertal failure, iron overload interferes with the correct function of the hypothalamic–pituitary axis, leading to hypogonadotrophic hypogonadism and growth failure, but the mechanisms are still unclear. Aim of this study was to investigate the mechanisms of iron toxicity in vitro in GN-11 cells, a model of immature and migratory GnRH neurons. Gene expression analysis by semi-quantitative PCR showed that GN-11 express the iron proteins ferritin (a primary intracellular iron-storage protein) and transferrin (iron-binding extracellular glycoprotein that controls the level of free Fe and deliver iron to cells), as well as hepcidin (an iron regulatory hormone). Exposure of GN11 cells to 150 μM ferric ammonium citrate (FAC) resulted in the inhibition (−35%, P<0.05) of fetal bovine serum (FBS)-induced chemo-migration, assessed by Boyden chamber assay. Pre-treatment with 100 μM deferoxamine, a specific iron chelator, reverted the above reported effect. Time-course experiments showed that 150 μM FAC was associated with induction of phosphorylation of both extracellular signal-regulated kinase (ERK) and 5′ adenosine monophosphate-activated protein kinase (AMPK) after 10 min treatment, as evaluated by Western blotting. Specific ERK and AMPK inhibitors, U0126 and Compound C, respectively, abolished FAC-mediated signaling. Moreover, U0126 and Compound C (both 10 μM) counteracted FAC-driven phosphorylation of acetyl-CoA carboxylase, an AMPK downstream protein. In conclusion, the present data, though preliminary, show that acute iron treatment negatively affects the migration of GN-11 neurons in vitro, and is associated with the activatio of ERK and AMPK signaling pathways. We hypothesize that iron overload may impair migration of GnRH neurons from the olfactory placode into forebrain and hypothalamus, where they promote reproductive competence
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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