1,720,972 research outputs found
P-glycoprotein in HK-2 proximal tubular cells: upregulation by cyclosporin and dexamethasone
No full textP-glycoprotein in HK-2 proximal tubule cell line
No full textP-glycoprotein (PGP) is an efflux pump physiologically expressed in the apical membrane of the proximal tubular cells. PGP may play a role in the elimination of exogenous substances such as chemotherapeutic drugs, calcium channel blockers and immunosuppressors. The involvement of renal PGP in the transport of endogenous substrates is under investigation. HK-2 is an immortalized proximal tubule cell fine from normal adult human kidney, reported to retain a phenotype indicative of a well-differentiated state. No data regarding expression and/or activity of PGP in this cell line are available The aim of this study was to ascertain the usefulness of HK-2 cell line to investigate the properties and roles of PGP in proximal tubular cells. PGP expression in HK-2 cells was determined by immunoblotting analysis using the monoclonal antibody C219. The activity of PGP was assessed by measuring the transport of the fluorescent probe Rhodamine 123 (R-123) in intact cell monostrates. The interactions of putative PGP modulators, including verapamil and cyclosporin A were also evaluated. Western blot revealed a C219 immunoreactive band of about 150 kDa consistent with the presence of PGP. HK-2 cells preloaded with R-123 rapidly effluxed the dye, the efflux being inhibited by verapamil. Verapamil and, to a major extent cyclosporin A, significantly increased R-123 intracellular accumulation. PGP immunoblottable amount was increased when cells were cultured in the presence of either cyclosporin A or dexamethasone. The results suggest that the HK-2 cells, among the various differentiation features of proximal tubules, retain also the expression of a functional PGP in their membranes and that both PGP activity and expression may be modulated by drugs. Therefore, HK-2 line appears a suitable and promising tool for the study in vitro of renal transport processes dependent on PGP
Bladder cumulative method: a reliable technique for the measurement of GFR in renal insufficiency
No full text
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
Tumor-associated trypsin inhibitor (TATI) and renal function
No full textTumor-associated trypsin inhibitor (TATI) is a low molecular weight protein employed as tumor marker. To evaluate the role of the kidney in the clearance of TATI we studied the relationship of serum TATI with the glomerular filtration rate (GFR), and for comparison the relationships of beta 2-microglobulin (beta(2)m) and creatinine with GFR. Urine excretion and renal extraction of TATI were also determined. The decrease in GFR was accompanied by an increase in blood levels of TATI, beta(2)m and creatinine. Serum TATI increased 12.4 times in patients with renal failure (GFR < 20 ml/min) with respect to subjects with normal renal function (P < 0.001, non-parametric Mann-Whitney test), while beta(2)m increased 7.3 times (P < 0.001) and creatinine 4.7 limes (P < 0.001). In patients with GFR 60 to 40 ml/min, only the increase in TATI was statistically significant (P < 0.005). Renal excretion of TATI was low but it increased progressively in renal failure. Renal extraction ranged from 13% to 41%, for a mean 24.87. These results suggest that TATI is handled by the kidney and that it is a sensitive marker of reduction in renal function
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
A reappraisal of the bladder cumulative method as a reliable technique for the measurement of glomerular filtration rate (vol 20, pg 257, 1998)
No full textIn order to quantify, the decline in renal function, repeated measurements of GFR are necessary. The conventional procedure is cumbersome and time expending so that alternative clearance techniques ave needed. We propose a simple isotopic technique for measuring GFR by Tc-99m-DTPA and external counting of the bladder by gamma camera (bladder cumulative method). This consists in the measurement by external counting of the amount of labelled filtration marker accumulated in the bladder after intravenous bolus injection. In 36 adult patients with all degrees of renal impairment (serum creatinine 0.9-9.3 mg/dL) GFR was measured twice, once by the conventional method (continuous i.v. infusion of the filtration marker and urine collection by spontaneous voiding) and once by the bladder cumulative method. Tc-99m DTPA was used in performing both methods. A satisfactory agreement was found between GFR measured by bladder cumulative method (BCM) and by conventional method (CM). The BCM averaged 60.0 +/- 36.7 mL/min and the CM +/- SD averaged 62.8 +/- 36.6 mL/mm. The ratio BCM/CM +/- SD was 0.95 +/- 0.14 (y = 0.94x + 1.14; r = 0.94). Considering the 17 patients with renal insufficiency (GFA < 60 mL/min) an even better agreement between the two methods was found. In these patients the BCM averaged 28.4 +/- 17.2 mL/min; the CM averaged 29.1 +/- 16.6 mL/min; and the ratio BCM/CM was 0.96 +/- 0.08 (y = 1.03x - 1.47; r = 0.99). The day-to-day variability of BCM, studied in another 11 patients, was lower than that of creatinine clearance (variation coefficient for duplicate measurements: 7.18 +/- 6.65 SD for BCM, 15.68 +/- 8.80 SD for CM, p < 0.01). The bladder cumulative method is a simple procedure for the accurate measurement of GFR, in particular in patients with renal insufficiency. It represents a reliable tool for estimating the decline in renal function
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