1,721,008 research outputs found

    Iron-replete hemodialysis patients do not require higher EPO dosages when converting from subcutaneous to intravenous administration: results of the Italian Study on Erythropoietin Converting (ISEC).

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    BACKGROUND: Previous studies reported significant increases in epoetin dosages when converting hemodialysis patients from subcutaneous (SC) to intravenous (IV) administration. More recent studies that corrected for iron deficiency found a much lower, if any, increase in epoetin dosage and/or decrease in hemoglobin (Hb) level after conversion from SC to IV epoetin administration. Therefore, the matter is still open for debate. METHODS: This multicenter observational study evaluated stable hemodialysis patients without iron deficiency who had a stable SC epoetin dosage and Hb level of 10 g/dL or greater (> or =100 g/L) at the time of study enrollment. Data for epoetin dosage, anemia, and inflammatory markers were collected retrospectively during the last 6 months of SC epoetin treatment and prospectively for 6 months after conversion to IV administration. The primary efficacy assessment was difference in Hb levels and epoetin dosages between patients administered epoetin SC and IV. Changes in values for iron stores, C-reactive protein, intact parathyroid hormone, and albumin were monitored as control parameters. RESULTS: Data were analyzed for 262 hemodialysis patients from 6 Italian centers. Overall, mean Hb levels were similar with SC and IV epoetin administration (11.49 g/dL [114.9 g/L] and 11.44 g/dL [114.4 g/L]). Mean epoetin dosages also were similar with SC and IV administration (7,185 and 7,270 IU/wk). In patients requiring epoetin dosages of 12,000 IU/wk or greater at study entry, mean dosages tended to decrease after conversion to IV administration. There were no significant changes in control parameters. CONCLUSION: Conversion from SC to IV epoetin administration did not result in changes in Hb levels or epoetin dosage requirements in iron-replete hemodialysis patients

    Cardiovascular stability during haemodialysis, haemofiltration and haemodiafiltration

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    Several comparative studies have claimed that procedures based substantially or exclusively on pressure-driven water-solute transport, such as haemodiafiltration or haemofiltration, afford better protection of the cardiovascular tolerance to fluid removal than conventional haemodialysis. During each depurative modality, several factors are set in motion that might impact, each in its own right, upon the haemodynamic response to fluid withdrawal. To explore the haemodynamic effect of each of them singularly, one needs to keep all other components unvaried. However, this is very difficult to accomplish. For instance, to confirm the alleged greater protection of cardiovascular stability by pure convection vs diffusion, one needs to keep unvaried all the other factors potentially affecting haemodynamic tolerance, i.e. the rate of body fluid removal, the membrane, the buffer, the blood temperature in the extracorporeal circuit, depuration efficiency, the sodium balance, the fluid sterility and so on. Such studies are still awaited. However, clinical trials published to date have not resolved the question of whether haemofiltration and haemodiafiltration provide a better haemodynamic tolerance to fluid removal. If we limit our consideration to controlled trials only, most prospective studies have adopted a cross-over design implemented on very small patient samples and for very short periods. Such an approach is liable to generate misleading results because the incidence of dialysis hypotension often fluctuates from time to time. Owing to such fluctuations, results can be strongly affected by the 'order effect' of the cross-over from one technique to the other. The negative results provided by parallel comparisons of procedures should be taken with caution because patients samples did not include a suitable proportion of unstable patients

    Going Beyond Counting First Authors in Author Co-citation Analysis

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    The 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

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    “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

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    We 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

    Predictivity of survival according to different equations for estimating renal function in community-dwelling elderly subjects

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    Background. Detection of subjects with early chronic kidney disease (CKD) is important because some will progress up to stage 5 CKD, and most are at high risk of cardiovascular morbidity and mortality. While validity and precision of estimated glomerular filtration rate (eGFR) equations in tracking true GFR have been repeatedly investigated, their prognostic performance for mortality has not been hitherto compared. This is especially relevant in an elderly population in whom the risk of death is far more common than progression. Methods. We analysed data of participants in the InCHIANTI study, a community-based cohort study of older adults. Twenty-four-hour creatinine clearance (Ccr), Cockcroft-Gault (C-G) and Modification of Diet in Renal Disease (MDRD)-derived equations (six and four input variables) were calculated at enrolment (1998-2000), and all-cause mortality and cardiovascular mortality were prospectively ascertained by Cox regression over a 6-year follow-up. Results. Of the 1270 participants, 942 (mean age 75 years) had complete data for this study. The mean renal function ranged from 77 ml/min/1.73 m(2) by Ccr to 64 ml/min/1.73 m(2) by C-G. Comparisons among equations using K/DOQI staging highlight relevant mismatches, with a prevalence of CKD ranging from 22% (MDRD-4) to 40% (C-G). Reduced renal function was a strong independent predictor of death. In a Cox model-adjusted for demographics, physical activity, comorbidities, proteinuria and inflammatory parameters-participants with Ccr 60-90 ml/min/1.73 m(2) and Ccr 90 ml/min/1.73 m(2). For the C-G, the group with values 90 ml/min/1.73 m(2) (HR 2.59, 95% CI: 1.13-5.91). The classification based on the MDRD formulae did not provide any significant prognostic information. The adjusted risk of all-cause mortality followed a similar pattern when Ccr and estimating equations were introduced as continuous variables or dichotomized as higher or lower than 60 ml/min. C-G was the best prognostic indicator of cardiovascular mortality. Possibly, Ccr and C-G are better prognostic indicators than MDRD-derived equations because they incorporate a stronger effect of age. Conclusions. In a South-European elderly population, the prevalence of CKD is high and varies widely according to the method adopted to estimate GFR. Researchers and clinicians who want to capture the prognostic information on mortality related to kidney function should use the Ccr or C-G formula and not MDRD equations. These results highlight the importance of strategies for early detection and clinical management of CKD in elderly subjects

    Omega-3 and renal function in older adults.

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    Chronic kidney disease (CKD) is a major public health problem and can result in end-stage renal disease with need for dialysis or transplantation. In Europe up to 12% of the adult population had some renal impairment, while in the United States the end stage of CKD has increased dramatically from 209.000 in 1991 to 472.000 in 2004. Diabetes and hypertension are major causes of kidney pathology. Infection, particularly ascending infection, is more common with increasing age, as both immune function declines and associated pathology predisposing to infection, such as obstructive uropathy, becomes more common. Most pathological changes in the kidney appear to be initiated by oxidative stress, followed by an inflammatory reaction. Oxidative stress results from an imbalance between free radicals and their detoxification by endogenous and exogenous scavengers, including polyunsaturated fatty acids (PUFA). Recent studies showed that PUFA supplementation slowed the rate of loss of renal function in patients with IgA nephropathy. Then, studies of omega-3 supplementation in dialysis patients describe salutary effects on triglyceride levels and dialysis access patency. We examined the relationship between total plasma PUFA levels and change in creatinine clearance over a three-year follow-up in the older persons enrolled in the InCHIANTI study, a population-based epidemiology study conducted in Tuscany, Italy. This study showed that older adults with low total plasma PUFA levels have a greater decline in creatinine clearance over three years of follow-up. These findings suggest that a higher dietary intake of PUFA may be protective against progression to chronic kidney disease
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