1,721,078 research outputs found
Renal metabolism of C-peptide in patients with early insulin-dependent diabetes mellitus
No full textRenal metabolism of C-peptide was studied in 6 patients with early insulin-dependent diabetes mellitus (IDDM) with residual beta cell activity and in 11 nondiabetic subjects by the arterial-venous difference technique both in the postabsorptive state and for 80 min after ingestion of an amino acid mixture (0.8 g/kg). Urinary C-peptide (Cp) excretion, glomerular filtration rate and renal plasma flow were also measured. In the postabsorptive state in IDDM, renal uptake of Cp is reduced, while its urinary excretion and clearance are significantly increased. As a result, net renal extraction is markedly reduced. In contrast to controls, renal uptake and net extraction of C-peptide after amino acid ingestion do not increase in patients; the peritubular uptake evident in normal subjects is not detectable. Urinary excretion and clearance of Cp remain significantly higher in IDDM patients. In both groups, renal uptake of C-peptide is directly related to its renal load: however, in IDDM, the increase in Cp uptake for each increment in renal load is 35% lower than in controls (p < 0.001). Furthermore, as opposed to controls, urinary Cp excretion is not correlated with its arterial levels. Therefore IDDM patients have marked defects in renal handling of endogenous Cp, regarding both the amount metabolized by renal tissue and that reabsorbed by tubular cells. These data indicate an early alteration in the diabetic kidney that also impairs the reliability of urinary Cp evaluation as an index of residual beta cell activity in IDDM patients
Amino acid metabolism, substrate availability and the control of protein dynamics in the human kidney
No full textIF=0.97
Testosterone Disorders and Male Hypogonadism in Kidney Disease
No full textChronic kidney disease (CKD) causes substantial alterations in the male endocrine system, which affect puberty, libido, and sexual function. A major effect of CKD is a reduction in testosterone levels because of both primary and hypogonadotrophic hypogonadism. In addition to impairment of pubertal growth and sexual maturation in children with CKD, clinical evidence suggests that uremic hypogonadism strongly contributes to several CKD complications, including erectile dysfunction, muscle wasting and frailty, anemia, decreased bone mineralization, depression, and cognitive impairment. This review focuses on a reappraisal of the physiologic role of testosterone, with an emphasis on the hypogonadal condition linked to CKD and its complications
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
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