1,720,977 research outputs found
Helicobacter pylori infection, chronic gastritis, and proton pump inhibitors
No full textThe proton pump inhibitors (PPIs) omeprazole, lansoprazole, and pantoprazole are widely used as antisecretory drugs and, in association with antibiotics, for the treatment of Helicobacter pylori infections. PPIs possess antibacterial activity against H. pylori in vitro, and may also exert an anti-inflammatory effect by interfering with the cellular immune response to infection. Their antimicrobial activity is selective for H. pylori. Lansoprazole is the most effective, although its bactericidal activity is similar to that of omeprazole. Pantoprazole is the least effective. The mechanisms that account for the antibacterial effects of PPIs may depend on a structural similarity of PPIs to antibiotics which are active against H. pylori, on the inhibition of bacterial urease exerted by PPIs, or on the possible interaction of PPIs with bacterial ATPases that regulate the transmembrane ion flux. Recent studies have shown that PPIs have anti-inflammatory actions and can interfere with the host-bacteria interactions. Lansoprazole can bind to polymorphonuclear leukocytes that infiltrate the gastric mucosa colonized by H. pylori and can thus inhibit the oxidative burst of activated inflammatory cells. In an in vivo study, lansoprazole reduced the degree of activity of histologic gastritis independently of the presence of H. pylori. In another study, omeprazole was capable of inhibiting the cytotoxic activity of NK T cells. Investigation of PPI interactions with H. pylori activities and the cellular immune response to the infection may help us to understand the pathogenic mechanisms of H. pylori-associated diseases and enable clinicians to better treat the
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Bedtime administration of lansoprazole does not modify its greater efficacy vs ranitidine in the acute and long-term treatment of duodenal ulcer. Results from a multicentre, randomised, double blind clinical trial.
No full textBACKGROUND/AIMS:
The efficacy of proton pump inhibitors is considered linked to morning, fasting administration. The aim of the present study was to assess efficacy and tolerability of the proton pump inhibitors lansoprazole given at bedtime as compared to ranitidine, both in acute and maintenance treatment of duodenal ulcer.
METHODS:
This was a randomised double blind study. The patients were divided into 4 treatment groups as follows (healing/maintenance): 1) lansoprazole 30 mg/lansoprazole 15 mg; 2) lansoprazole 30 mg/placebo; 3) ranitidine 300 mg/ranitidine 150 mg; 4) ranitidine 300 mg/placebo. Healing and relapse of ulcers were assessed by endoscopy at 2, 4 and 8 weeks and then at 3, 6, 9 and 12 months during follow-up.
RESULTS:
A total of 132 patients were enrolled in 9 study centres. The cumulative healing rates (per-protocol analysis) at 2, 4 and 8 weeks were 57.4%, 83.9% and 89.2% in the lansoprazole group and 30%, 70.2% and 78.7% in the ranitidine group (p = 0.01 at 2 weeks). The 12-month cumulative relapse rate (intent-to-treat analysis) was lower in the lansoprazole/lansoprazole group (23.3%), than those reported by the other groups of patients lansoprazole/placebo (39.3%); ranitidine/ranitidine (45.8%); ranitidine/placebo (50%). The disease-free time from healing was significantly longer for lansoprazole treated patients (p < 0.05). All treatments were very well tolerated, only few minor adverse events being reported.
CONCLUSIONS:
Lansoprazole maintains its greater efficacy vs ranitidine even when administered at bedtime, both for the healing and for the maintenance treatment of duodenal ulcer. Lansoprazole (half dose formulation) may be useful for the treatment of patients requiring long-term acid suppression
Variations on the Author
Get PDF“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
Get PDFWe 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
Get PDFWe 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
- …
