1,721,086 research outputs found
Gastro-esophageal reflux in children
No full textGastro-esophageal reflux (GER) is common in infants and children and has a varied clinical presentation: from infants with innocent regurgitation to infants and children with severe esophageal and extra-esophageal complications that define pathological gastro-esophageal reflux disease (GERD). Although the pathophysiology is similar to that of adults, symptoms of GERD in infants and children are often distinct from classic ones such as heartburn. The passage of gastric contents into the esophagus is a normal phenomenon occurring many times a day both in adults and children, but, in infants, several factors contribute to exacerbate this phenomenon, including a liquid milk-based diet, recumbent position and both structural and functional immaturity of the gastro-esophageal junction. This article focuses on the presentation, diagnosis and treatment of GERD that occurs in infants and children, based on available and current guidelines
Pediatric esophageal high-resolution manometry: utility of a standardized protocol and size-adjusted pressure topography parameters
No full textIsolation and characterisation of mouse intestinal mesoangioblasts
Full text linkAIMS AND OBJECTIVES: Children suffering from intestinal failure (IF) endure considerable morbidity and overall have poor survival rates, complicated by the shortage of organs available for transplantation. Therefore, new therapeutic approaches are pivotal if outcomes are to be improved. Over the past years, tissue engineering (TE) has emerged as a possible alternative treatment for many congenital and acquired conditions. TE aims at creating bioengineered organs by means of combining scaffolds with appropriate cell types, which in the intestine are organised within a multilayer structure. In order to generate functional intestine, this cellular diversity and organisation will need to be recreated. While the cells for the epithelial, neural and vascular compartments have been well defined, so far, less attention has been put on the muscular compartment. More recently, mesoangioblasts (MABs) have been identified as a novel source for tissue regeneration since they are able to give rise to vascular and other mesodermal derivatives. To date MABs have not been successfully isolated from intestinal tissue. Therefore, our aim was to demonstrate the possibility of isolating MABs from adult mouse small intestine. MATERIALS AND METHODS: All experiments were carried out using small intestinal tissues from C57BL/6J mice. We applied an established protocol for MAB isolation from the isolated neuromuscular layer of the small intestine. Cultured cells were stained for Ki67 to assess proliferation rates as well as for a panel of pericyte markers to determine their phenotype. RESULTS: Cells were successfully isolated from gut biopsies. Cultured cells showed good proliferative capacity and positivity for at least three pericytes markers found in vessels of the gut neuromuscular wall: neuron-glial antigen 2, alkaline phosphatase and platelet-derived growth factor β. CONCLUSION: This proof-of-principle study lays the foundation for further characterization of MABs as a possible cell source for intestinal smooth muscle regeneration and TE.sponsorship: The authors would like to acknowledge the NIHR Great Ormond Street Hospital Biomedical Research Centre which supports all research at Great Ormond Street Hospital NHS Foundation Trust and UCL Great Ormond Street Institute of Child Health. The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR or the Department of Health. Additional support for this project was provided by Horizon 2020 INTENS funding. NT is supported by Great Ormond Street Hospital Children's Charity. SP's PhD studentship is funded through a GOSHCC grant awarded to NT. CM is supported by Guts UK (Derek Butler Fellowship). PDC is supported by National Institute for Health Research (NIHR-RP-2014-04-046). (NIHR Great Ormond Street Hospital Biomedical Research Centre, Horizon 2020 INTENS funding, Great Ormond Street Hospital Children's Charity, GOSHCC, Guts UK (Derek Butler Fellowship), National Institute for Health Research|NIHR-RP-2014-04-046)status: Publishe
Update on foregut molecular embryology and role of regenerative medicine therapies
Full text linkEsophageal atresia (OA) represents one of the commonest and most severe develop-mental disorders of the foregut, the most proximal segment of the gastrointestinal (GI) tract (esophagus and stomach) in embryological terms. Of intrigue is the common origin from this foregut of two very diverse functional entities, the digestive and respiratory systems. OA appears to result from incomplete separation of the ventral and dorsal parts of the foregut during development, resulting in disruption of esophageal anatomy and frequent association with tracheo-oesophageal fistula. Not surprisingly, and likely inher-ent to OA, are associated abnormalities in components of the enteric neuromusculature and ultimately loss of esophageal functional integrity. An appreciation of such develop-mental processes and associated defects has not only enhanced our understanding of the etiopathogenesis underlying such devastating defects but also highlighted the potential of novel corrective therapies. There has been considerable progress in the identification and propagation of neural crest stem cells from the GI tract itself or derived from pluripotent cells. Such cells have been successfully transplanted into models of enteric neuropathy confirming their ability to functionally integrate and replenish missing or defective enteric nerves. Combinatorial approaches in tissue engineering hold signifi-cant promise for the generation of organ-specific scaffolds such as the esophagus with current initiatives directed toward their cellularization to facilitate optimal function. This chapter outlines the most current understanding of the molecular embryology underlying foregut development and OA, and also explores the promise of regenerative medicine
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
- …
