1,721,001 research outputs found
Human atrial cell models to analyse haemodialysis-related effects on cardiac electrophysiology: Work in progress
Full text linkDuring haemodialysis (HD) sessions, patients undergo alterations in the extracellular environment, mostly concerning plasma electrolyte concentrations, pH, and volume, together with a modification of sympathovagal balance. All these changes affect cardiac electrophysiology, possibly leading to an increased arrhythmic risk. Computational modeling may help to investigate the impact of HD-related changes on atrial electrophysiology. However, many different human atrial action potential (AP) models are currently available, all validated only with the standard electrolyte concentrations used in experiments. Therefore, they may respond in different ways to the same environmental changes. After an overview on how the computational approach has been used in the past to investigate the effect of HD therapy on cardiac electrophysiology, the aim of this work has been to assess the current state of the art in human atrial AP models, with respect to the HD context. All the published human atrial AP models have been considered and tested for electrolytes, volume changes, and different acetylcholine concentrations. Most of them proved to be reliable for single modifications, but all of them showed some drawbacks. Therefore, there is room for a new human atrial AP model, hopefully able to physiologically reproduce all the HD-related effects. At the moment, work is still in progress in this specific field
Electrolytes and COVID-19: challenges and caveats in clinical research studies
No full textBackground The prognostic impact of electrolyte disorders in hospitalized COVID-19 patients is unclear.
Methods The study included all adult patients hospitalized for COVID-19 in four hospitals in Northern Italy between January
2020 and May 2021 with at least one serum potassium and sodium measurement performed within 3 days since admission.
Primary outcome was in-hospital death; secondary outcome was Intensive Care Unit (ICU) admission. A cause-specific Cox
proportional-hazards regression model was used for investigating the association between potassium and sodium (as either
categorical or continuous variables) and mortality or admission to ICU.
Results Analyses included 3,418 adult hospitalized COVID-19 patients. At multivariable analysis, both hyperkalemia (Hazard
Ratio, [HR] 1.833, 95% Confidence Interval [CI] 1.371–2.450) and sK above the median (K 5.1 vs 4.1 mmol/L: HR
1.523, 95% CI 1.295–1.798), and hypernatremia (HR 2.313, 95%CI 1.772–3.018) and sNa above the median (Na 149 vs 139
mmol/L: HR 1.442, 95% CI 1.234–1.686), were associated with in-hospital death, whereas hypokalemia and hyponatremia
were not. Hyponatremia was associated with increased hazard of ICU admission (HR 1.884, 95%CI 1.389–2.556).
Conclusions Electrolyte disorders detected at hospital admission may allow early identification of COVID-19 patients at
increased risk of adverse outcomes
How to Apply European and American Guidelines on High Blood Pressure in Children and Adolescents. A Position Paper Endorsed by the Italian Society of Hypertension and the Italian Society of Pediatrics
No full textChildren are defined as hypertensive when their blood pressure values equal or exceed the 95th percentile of the blood pressure value distribution in a pediatric population, according to gender, age and height. The population on which reference tables are based is of fundamental importance to establish the threshold values for the diagnosis of hypertension in pediatric age. Before 2017, both American and European guidelines used nomograms created in the same reference population which included children of all weight classes. Given the close and well-known association between hypertension and excess weight in childhood, the 2017 American guidelines proposed new reference nomograms excluding subjects with overweight and obesity from the "historical" reference population. Furthermore, the new American guidelines suggested a fixed cut-off of 130/80 mmHg, starting from 13 years and regardless of gender and height, to make the diagnosis of hypertension. In this document, the Italian Hypertension Society (SIIA) and the Italian Pediatric Society (SIP) jointly discuss a number of issues raised by the new American guidelines that involve the entire medical community, and also address the definition of arterial hypertension in the transition phase between childhood and adulthood
Relationship between endothelin and nitric oxide pathways in the onset and maintenance of hypertension in children and adolescents
No full textThe mechanisms that regulate blood pressure are numerous and complex; one mechanism that plays an important role in this scenario is represented by the balance between the vasoconstrictor effect of endothelin-1 and the vasodilator effect of nitric oxide. While there is agreement on the fact that increased endothelin-1 activity and decreased nitric oxide bioavailability are present in hypertensive adults, the situation is less clear in children and adolescents. Not all studies agree on the finding of an increase in plasma endothelin-1 levels in hypertensive children and adolescents; in addition, the picture is often confused by the concomitant presence of obesity, a condition that stimulates the production of endothelin-1. Furthermore, there is recent evidence that, in younger obese and hypertensive subjects, there is an overproduction of nitric oxide, rather than a reduction. This condition may change over time, causing endothelial dysfunction due to a reduced availability of nitric oxide in hypertensive adolescents. The purpose of this review is to address the main biochemical and pathophysiological aspects of endothelin and nitric oxide involvement in hypertension and to summarize the available scientific evidence on their role in the onset and maintenance of high blood pressure in children and adolescents
Management of hyperkalemia in patients with kidney disease: a position paper endorsed by the Italian Society of Nephrology
No full textHyperkalemia (HK) is the most common electrolyte disturbance observed in patients with kidney disease, particularly in those in whom diabetes and heart failure are present or are on treatment with renin-angiotensin-aldosterone system inhibitors (RAASIs). HK is recognised as a major risk of potentially life threatening cardiac arrhythmic complications. When an acute reduction of renal function manifests, both in patients with chronic kidney disease (CKD) and in those with previously normal renal function, HK is the main indication for the execution of urgent medical treatment and the recourse to extracorporeal replacement therapies. In patients with end-stage renal disease, the presence of HK not responsive to medical therapy is an indication at the beginning of chronic renal replacement therapy. HK can also be associated indirectly with the progression of CKD, because the finding of high potassium values leads to withdrawal of treatment with RAASIs, which constitute the first choice nephro-protective treatment. It is therefore essential to identify patients at risk of developing HK, and to implement therapeutic interventions aimed at preventing and treating this dangerous complication of kidney disease. Current strategies aimed at the prevention and treatment of HK are still unsatisfactory, as evidenced by the relatively high prevalence of HK also in patients under stable nephrology care, and even in the ideal setting of randomized clinical trials where optimal treatment and monitoring are mandatory. This position paper will review the main therapeutic interventions to be implemented for the prevention, detection and treatment of HK in patients with CKD on conservative care, in those on dialysis, in patients in whom renal disease is associated with diabetes, heart failure, resistant hypertension and who are on treatment with RAASIs, and finally in those presenting with severe acute HK
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
Uric acid and arterial stiffness in children and adolescents: Role of insulin resistance and blood pressure
No full textSeveral studies describe the association between serum uric acid (SUA) and arterial stiffness in adults. Uric acid contributes through several mechanisms to the increase in blood pressure (BP) and adversely affects the insulin signaling pathway. Moreover, SUA predict the development of hypertension and insulin resistance up to type 2 diabetes. Early arterial stiffening, estimated by carotid-femoral pulse wave velocity (PWV), may already be present in pediatric age. Aim of our study was to investigate the relationship between SUA and PWV in a pediatric population and its interaction with insulin resistance and BP. In 322 children and adolescents (56.2% male, mean age 11.3 [SD 2.8] years), we measured weight, height, waist circumference, BP and PWV. We also assayed SUA and estimated glomerular filtration rate (eGFR) and calculated HOMA-index as a marker of insulin resistance. Simple and multiple regression analyses were performed to assess variables associated with PWV. Mediation models were applied to identify the direct and indirect effects of individual variables on PWV. On univariate analysis, age (p < 0.001), waist circumference-to-height ratio (p = 0.036), systolic and diastolic BP (SBP and DBP) z-score (p < 0.001), heart rate (p = 0.028), SUA (p = 0.002), HOMA-index (p < 0.001), and eGFR (p = 0.014) were significantly associated with PWV. The multiple regression model showed that only age (p = 0.028), SBP z-score (p = 0.006), and heart rate (p = 0.001) were significantly associated with PWV. The results were superimposable when the DBP z-score replaced the SBP z-score in the model. Mediation models showed that the effect of eGFR on PWV was fully mediated by SUA (p = 0.015) and that the effect of SUA on PWV was totally mediated by HOMA-index (p < 0.001). Both SUA (p < 0.01) and HOMA-index (p < 0.01) had a significant association with higher SBP (DBP) z-scores. The double mediation model including both BP and HOMA-index showed that the SUA effect on PWV was totally mediated by both variables (p = 0.005, for HOMA-index, p = 0.004, for SBP z-score and p = 0.007, for combined effect). The results were superimposable when the DBP z-score replaced the SBP z-score in the model. In conclusion, insulin resistance and BP are both important mediators of the association between SUA and vascular stiffness in pediatric age
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
Increased serum uric acid levels blunt the antihypertensive efficacy of lifestyle modifications in children at cardiovascular risk
No full textPrimary hypertension is a growing concern in children because of the obesity epidemic largely attributable to western lifestyles. Serum uric acid is known to be influenced by dietary habits, correlates with obesity, and could represent a risk factor for hypertension. Preliminary studies in children highlighted uric acid as a potentially modifiable risk factor for the prevention and treatment of hypertension. The effect of lifestyle changes (increase of physical activity and dietary modifications) on blood pressure values, weight status, and serum uric acid levels in a cohort of 248 children referred for cardiovascular risk assessment were evaluated over a mean 1.5-year follow-up. At baseline, 48% of children were obese and 50% showed blood pressure values >90th percentile. At follow-up, a significant improvement in weight class (24% obese; P<0.0001) and blood pressure category (22% >90th percentile; P<0.0001) was found. Systolic blood pressure z-score (P<0.0001), uric acid value (P=0.0056), and puberty at baseline (P=0.0048) were independently associated with higher systolic blood pressure z-score at follow-up, whereas a negative association was observed with body mass index z-score decrease during follow-up (P=0.0033). The risk of hypertension at follow-up was associated with body mass index (P=0.0025) and systolic blood pressure (P<0.0001) z-score at baseline and inversely related to delta body mass index (P=0.0002), whereas the risk of showing hypertension ≥99th percentile was more than doubled for each baseline 1 mg/dL increase of serum uric acid (P=0.0130). Uric acid is a powerful determinant of blood pressure over time, independent of lifestyle modifications
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