1,720,967 research outputs found
Temporal and spatial dynamics of organic chemicals in the environment with a multimedia fate model.
Full text linkIn this PhD thesis we have deal with different aspects of treatment and pathogenesis of diabetes mellitus. With regard to type 1 diabetes, we followed three different research lines clarifying aspects not yet well known on different types of patient transplants. Regarding type 2 diabetes, we studied the role of insular amyloid in the development and progression of the disease.
Transplantation is one of the possible therapies for type 1 diabetes and can be performed in patients who no longer respond to insulin therapy in satisfactory manner. For type 1 diabetes treatment there are three possible types of transplantation:
• Pancreas, often associated with kidney transplantation, is the only treatment for type 1 diabetes that can maintain long-term insulin independence and normoglycemia. In type 1 diabetes patients, chronic hyperglycemia leads to both microvascular and macrovascular damages probably due to overproduction of superoxides by the mitochondrial electron transport chain. In patients subjected to pancreas transplantation, it has been noted improvements in the microcirculation and in particular at the level of endothelial cells. In order to identify possible mechanisms by which transplantation improves microcirculation, we analyzed the expression of proteins involved in cellular response to oxidative stress in skin biopsies. According to the results obtained in our studies, some of the identified proteins may be considered as therapeutic targets for a new class of drugs, potentially able to correct cell modifications in cases where normoglycemia cannot be restored.
• Human purified pancreatic islet transplantation. The transplantation of human islets can successfully restore long-term insulin independence and improve glycemic control. However, the number of patients that remain insulin-independent decreases gradually in 2-3 years. Several hypotheses have been formulated in order to explain this negative response. One hypothesis is the “functional exhaustion" of a chronically overstimolated β cells mass. To better understand this possible mechanism, we studied at morphological, immunohistochemical and ultrastructural level the pancreatic islets before and after human islet cells transplantation in athymic nude mice made diabetic.
• Stem cell transplantation. Stem cells seem to be the new frontier for the treatment of type 1 diabetes. Several stem cell types have been identified as potential progenitors of pancreatic β cells and mesenchymal stem cells (MSC) seem to be a possible source of them. In addition, MSCs have immunomodulatory effects as demonstrated in several researches in which these cells have been used to reduce
the burden of a variety of immune-mediated diseases. Since type 1 diabetes is an autoimmune disorder, we explored the possibility to use MSCs transplantation as a therapeutic approach. For this reason, we characterized MSCs obtained from diabetes susceptible (NOD) mice and from diabetes-resistant (BALB/c) mice. After, we injected MSCs into pre-diabetic NOD mice and we evaluated their immunomodulatory effects in vivo.
It has been demonstrated that amyloid deposits are one of the main morphological alteration of the islets of Langerhans in patients affects by long-standing type 2 diabetes. Typically, islet amyloid derives from deposition of amylin which is synthesized and stored in pancreatic β cells together with insulin. Amylin is produced as a pro-peptide and cut by specific proteases. It has been showed in Alzheimer's patients that the protease BACE 1 is involved in amyloid plaques production. In addition, a BACE 1 homologue called BACE 2 has been identified and localised in most adult tissues such as the pancreatic one. However, the role of BACE 2 still remains unclear. By using immunohistochemical, ultrastructural and immunocytochemical techniques, we identified and localised BACE 2 in secretory granules of mice and rats pancreatic β cells. The data collected in our studies could be considered as a starting point for further investigations on human normal and diabetic pancreases. For instance, the correlation between BACE 2 expression and amyloid deposition could help to better understand a possible role of BACE 2 in islet amyloidosis and consequently could improve our understanding of the type 2 diabetes disorder.
However, it is not yet clear if amyloidosis is a primary or secondary event in the pathogenesis of diabetes. In order to better understand this situation, we used the Papio hamadryas (baboon) as an in vivo model. Indeed, baboons spontaneously develop type 2 diabetes associated with obesity as in humans, hypothesizing a similarity in diabetes pathogenesis between the two species. Our results strongly support that the insular amyloidosis associated with β cell apoptosis, α cell proliferation and hypertrophy are determinants of islets dysfunctional remodeling and hyperglycemia in baboons. In addition, our studies allow to hypothise a correlation between severity of amyloidosis, age and fasting plasma glucose levels
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
Carboxyl ester lipase (CEL) expression in normal pituitary gland and pituitary adenomas. Possible role in the modulation of hormone secretion via ceramide pathway.
No full textEspressione immunoistochimica di MGMT nei carcinomi colorettali con assenza di elevata instabilità dei microsatelliti (MSI)
No full textDispelling 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
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