1,721,089 research outputs found
Congenital Kidney Diseases
No full textThis chapter focuses on the prospects of new therapies that can be used for congenital kidney diseases, including gene therapies, the use of renal precursor transplantation, and some other novel strategies. Diverse methodologies are devised to introduce genes into mammalian cells, including transfection of DNA by physical means and transduction by viruses. Gene transfer is relatively easy to achieve and can be highly efficient in the artificial and controlled environment of cell culture. An alternative to genetically engineering the kidney is to rebuild a damaged or malformed kidney with new cells. Laboratories demonstrate that it is possible to harvest murine metanephroi in the first days after the organs begin to form and transplant them into sites in the postnatal animal where the embryonic organ would form mature structures, including vascular glomeruli, which filters blood to make urine. The concept of using metanephric kidney transplants to replace the function of failing host kidneys is investigated extensively in a murine model in which rudiments are transplanted into the omentum around the peritoneal cavity where they grow and connect with the host vascular system. After a period of growth, the ureter of the transplanted organ can be anastomosed surgically with the lower urinary tract of the host, and these transplants have a high enough glomerular filtration rate to maintain the life of the host when it is rendered anephric. The transplantation of fetal kidney cells may also offer the additional advantage of rendering the host “tolerant” to immune attack from the host
Development of Kidney Blood Vessels
No full textThe adult mammalian kidney is a highly vascular organ, receiving 20% of the cardiac output. This chapter discusses the anatomy of developing kidney vessels, including the genesis of renal arteries, glomerular capillaries, and the vasa recta microcirculation in the most often used experimental model—the mouse metanephros. Studies have been performed to address the origin of metanephric vessels and some experimental evidence supports the existence of both angiogenesis—the ingrowth of capillaries into the embryonic organ—and vasculogenesis—the in situ differentiation of endothelia. Diverse vascular growth factors are expressed in the developing kidney and these molecules direct the growth of renal blood vessels: they include vascular endothelial growth factor (VEGF) and the angiopoietins, which signal through receptor tyrosine kinases expressed by endothelial precursors. Less is known about cell adhesion molecules and transcription factors in the context of metanephric blood vessel development, although these classes of molecule are certainly important in vessel formation elsewhere in the embryo. The chapter focuses on the morphogenesis of the renal vasculature
Maldevelopment of the Human Kidney and Lower Urinary Tract
No full textThis chapter focuses on the maldevelopment of human kidney and lower urinary tract, which include the ureter and urinary bladder. Renal malformations are the major cause of chronic renal failure in children. With advances in technology, babies with minimal renal function can be dialyzed from birth and toddlers can receive kidney transplants from the age of one year. The chapter describes the possible causes of human kidney and lower urinary tract malformations, which can be classified into two categories: (1) mutations, and possibly polymorphisms, of genes expressed during development, and (2) environmental influences on development, which can be further subdivided into changes that originate outside the fetus, such as alterations of maternal diet, and changes within the fetus that disrupt normal development, such as impairment of normal fetal urinary flow due to physical obstruction of the urinary tract. Human kidney or lower urinary tract malformation are reported in association with teratogens—angiotensin converting enzyme inhibitors, drugs used to treat high blood pressure cocaine, corticosteroids, ethanol, gentamycin, glucose, nonsteroidal anti-inflammatory drugs, and vitamin A and its derivatives
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
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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