1,720,989 research outputs found
Ultrasound scanning in fetal renal pelvis dilatation: not only hydronephrosis
Full text linkPelvic dilatation is the alteration of the urinary tractmost frequently detected by maternal-fetalultra-sound. Hydronephrosis is not a diagnosis; it is an imagefinding. The diagnosis is the cause that produces it. Since pelvic dilatation is relatively frequent in thenormal fetus, and the definition and diagnosis of hy-dronephrosis are difficult, once it is detected, adequate follow-up is required. Therefore, it is important for the urologist and obstetrician to understanddifferential diagnosis and clinical implications in order to offer an accurate counselling to the parents
The PAX2 tanscription factor is expressed in cystic and hyperproliferative dysplastic epithelia in human kidney malformations.
No full textHuman dysplastic kidneys are developmental aberrations which are responsible for many of the very young children with chronic renal failure. They contain poorly differentiated metanephric cells in addition to metaplastic elements. We recently demonstrated that apoptosis was prominent in undifferentiated cells around dysplastic tubules (Winyard, P.J.D., J. Nauta, D.S. Lirenman, P. Hardman, V.R. Sams, R.A. Risdon, and A.S. Woolf. 1996. Kidney Int. 49:135-146), perhaps explaining the tendency of some of these organs to regress. In contrast, apoptosis was rare in dysplastic epithelia which are thought to be ureteric bud malformations. On occasion, these tubules form cysts which distend the abdominal cavity (the multicystic dysplastic kidney) and dysplastic kidneys may rarely become malignant. We now demonstrate that dysplastic tubules maintain a high rate of proliferation postnatally and that PAX2, a potentially oncogenic transcription factor, is expressed in these epithelia. In contrast, both cell proliferation and PAX2 are downregulated during normal maturation of human collecting ducts. We demonstrate that BCL2, a protein which prevents apoptosis in renal mesenchymal to epithelia] conversion, is expressed ectopically in dysplastic kidney epithelia. We propose that dysplastic cyst formation may be understood in terms of aberrant temporal and spatial expression of master genes which are tightly regulated in the normal program of human nephrogenesis
The biology of kidney malformations
No full textAvailable from British Library Document Supply Centre-DSC:DXN022919 / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo
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
Molecular mechanisms of human embryogenesis:Developmental pathogenesis of renal tract malformations
No full textThe focus of this review is the normal and abnormal development of the kidney and lower urinary tract; for convenience, we will refer to the whole system as the renal tract. The content represents a convergence among the clinical disciplines of histopathology, nephrology, and urology as well the basic sciences of developmental biology and molecular genetics. The story has considerable clinical relevance since diverse renal tract malformations are increasingly detected on fetal ultrasound screening and constitute major causes of chronic renal failure necessitating dialysis and kidney transplantation in children. Evidence is emerging that at least some of these disorders have a defined genetic basis; in others, an abnormal embryonic, or even maternal, environment may contribute to the pathogenesis. This field of study is frequently updated, with new discoveries being made almost every week. Hence this review can not be exhaustive or definitive, but instead highlights some specific areas of interest
Gene expression and cell turnover in human renal dysplasia
No full textKidney malformations are common causes of chronic renal failure in children. Dysplastic kidneys represent a unique model of perturbed epithelial-mesenchymal interaction which leads to the formation of malformed branching tubules surrounded by undifferentiated and metaplastic mesenchymal cells. We have found that human dysplastic epithelia express PAX2 (a transcription factor), BCL2 (a survival factor) and galectin-3 (a cell adhesion/signaling molecule). These genes are implicated in oncogenesis and their persistent expression may drive proliferation of dysplastic cysts, hence explaining the massive growth of some multicystic dysplastic kidneys. We have also detected prominent apoptosis in undifferentiated tissues around dysplastic epithelia, and this may provide a potential mechanism for the well-documented regression of dysplastic kidneys. Hence, although these kidneys may not have any excretory function, it is incorrect to consider them as 'end stage organs' because they are highly active in terms of cell turnover and gene expression; furthermore, these processes can be correlated with patterns of tissue growth and involution. Further elucidation of 'molecular lesions' in renal malformations may lead to novel therapies to enhance the differentiation of progenitor cells
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
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