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Phosphate control in dialysis
No full textAdamasco Cupisti,1 Maurizio Gallieni,2 Maria Antonietta Rizzo,2 Stefania Caria,3 Mario Meola,4 Piergiorgio Bolasco31Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy; 2Nephrology and Dialysis Unit, San Carlo Borromeo Hospital, Milan, Italy; 3Territorial Department of Nephrology and Dialysis, ASL Cagliari, Italy; 4Sant'Anna School of Advanced Studies, University of Pisa, Pisa, ItalyAbstract: Prevention and correction of hyperphosphatemia is a major goal of chronic kidney disease–mineral and bone disorder (CKD–MBD) management, achievable through avoidance of a positive phosphate balance. To this aim, optimal dialysis removal, careful use of phosphate binders, and dietary phosphate control are needed to optimize the control of phosphate balance in well-nourished patients on a standard three-times-a-week hemodialysis schedule. Using a mixed diffusive–convective hemodialysis tecniques, and increasing the number and/or the duration of dialysis tecniques are all measures able to enhance phosphorus (P) mass removal through dialysis. However, dialytic removal does not equal the high P intake linked to the high dietary protein requirement of dialysis patients; hence, the use of intestinal P binders is mandatory to reduce P net intestinal absorption. Unfortunately, even a large dose of P binders is able to bind approximately 200–300 mg of P on a daily basis, so it is evident that their efficacy is limited in the case of an uncontrolled dietary P load. Hence, limitation of dietary P intake is needed to reach the goal of neutral phosphate balance in dialysis, coupled to an adequate protein intake. To this aim, patients should be informed and educated to avoid foods that are naturally rich in phosphate and also processed food with P-containing preservatives. In addition, patients should preferentially choose food with a low P-to-protein ratio. For example, patients could choose egg white or protein from a vegetable source. Finally, boiling should be the preferred cooking procedure, because it induces food demineralization, including phosphate loss. The integrated approach outlined in this article should be actively adapted as a therapeutic alliance by clinicians, dieticians, and patients for an effective control of phosphate balance in dialysis patients.Keywords: phosphorus, hyperphosphatemia, dialysis, phosphate binders, diet, food preservative
Evaluation of Residual Kidney Function during Once-Weekly Incremental Hemodialysis
No full textBackground: The initial once-weekly administration of incremental hemodialysis to patients with residual kidney function (RKF) has recently attracted considerable interest. Methods: The aim of our study was to assess the performance of a series of different methods in measuring serum urea nitrogen and serum Cr (sCr) RKF in patients on once-weekly hemodialysis (1WHD). Evaluations were carried out by means of 24-h predialysis urine collection (Kr-24H) or 6-day inter-dialysis collection (Kr-IDI) and estimation of glomerular filtration rate based on (KrSUN + KrsCr)/2 for the purpose of identifying a simple reference calculation to be used in assessing RKF in patients on 1WHD dialysis. Ninety-five urine samples were collected from 12 1WHD patients. A solute solver urea and Cr kinetic modeling program was used to calculate residual urea and Cr clearances. Mann-Whitney U test, Pearson's correlation coefficient (R), and linear determination coefficient (R-2) were used for statistical analysis. Results: 1WHD patients displayed a mean KrSUN-IDI of 4.5 +/- 1.2 mL/min, while KrSUN-24H corresponded to 4.1 +/- 0.9 mL/min, mean KrsCr-IDI to 9.1 +/- 4.0 mL/min, and KrsCr 24H to 8.9 +/- 4.2 mL/min, with a high regression between IDI and 24-h clearances (for IDI had R-2 = 0.9149 and for 24H had R-2 = 0.9595). A good correlation was also observed between KrSUN-24H and (KrSUN + KrsCR/2) (R-2 = 0.7466, p < 0.01. Discussion: Urine collection over a 24-h predialysis period yielded similar results for both KrSUN and KrsCr compared to collection over a longer interdialytic interval (KrSUN + KrsCr)/2 could be applied to reliably assess RKF in patients on 1WHD. Conclusion: The parameters evaluated are suitable for use as a routine daily method indicating the commencement and continued use of the 1WHD Incremental Program
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
Role of SPECT/CT in the preoperative assessment of hyperparathyroid patients
No full textPurpose. Our purpose was to assess the clinical value and additional benefit of fusion single-photon computed tomography (SPECT) and computed tomography (CT) images in locating the parathyroids in a selected group of patients affected by primary (PHP) and secondary hyperparathyroidism (SHP). Materials and methods. Sixteen patients (11 women and five men; age range 35-80 years) with severe hyperparathyroidism (HP) (ten PHP. six SHP) were studied by ultrasound (US), and, after i.v. injection of 370 MBq of 99mTc-sestamibi, by planar parathyroid scintigraphy, SPECT and SPECT/CT using a dual-detector scintillation camera GE Infinia Hawkeye. All patients underwent parathyroidectomy. Results. US findings were inconclusive in 12/16 patients affected by multinodular goitre, and two probable eutopic parathyroid glands were identified. "Double phase" parathyroid scintigraphy identified 14 probable parathyroid glands, SPECT 23 (14 ectopic and nine eutopic) and SPECT/CT confirmed all 23 probable parathyroid lesions. offering more precise localisation and an evident improvement in diagnostic accuracy. Sixteen of these foci of increased uptake were hyperplastic parathyroid glands, six were adenomas, one was a parathyroid carcinoma and one was a thyroid follicular carcinoma. Surgical detection of the 23 sestamibi-positive lesions was correctly matched with 100% of SPECT/CT images and 61% of SPECT data alone. Hybrid imaging thus provided additional data in 39% of lesions, and in three patients with retrotracheal glands, it modified the surgical approach. Conclusions. We believe 99mTc-sestambi SPECT/CT to be a more reliable presurgical method to study a patient subgroup affected by PHP or SHP in whom conventional US and other scintigraphic methods have failed for intrinsic reasons due to the concomitant presence of multinodular goitre or ectopic parathyroid gland. The additional practical benefit derived from this methodology was evident. In fact, anatomical information provided by CT enables precise localisation of the functional abnormalities highlighted by SPECT, and both are essential to a correct surgical approach
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