19 research outputs found
Serum Creatinine Levels Are Significantly Influenced by Renal Size in the Normal Pediatric Population
Get PDFBackground and objectives Clinical and experimental data have shown that differences in nephron endowment result in differences in renal mass and predisposition to chronic renal failure, hypertension, and proteinuria. We hypothesized that a significant proportion of the variance in GFR, as estimated by serum creatinine, is attributable to differences in renal size in normal children. Design, setting, participants, & measurements A total of 1748 normal renal ultrasounds that were performed in children older than 6 months were reviewed. For each ultrasound, serum creatinine, serum blood urea nitrogen, and systolic and diastolic office BP were recorded. Renal size was evaluated as a function of renal length and thickness. All data were normalized for height, weight, age, and gender. Results When expressed as SD scores, a significant correlation was found between kidney size and serum creatinine (P < 0.0001) and between kidney size and serum blood urea nitrogen (P < 0.002). When dividing kidney size data per quintiles, a difference of 0.51 SD score in serum creatinine was observed between the lowest and highest quintile. No significant correlation was found with office BP measurements. Conclusions These data show that, even in the normal pediatric population, differences in renal function are significantly explained by differences in renal mass. Methodologic limitations of this study are likely to underestimate this relationship. Clin J Am Soc Nephrol 6: 107-113, 2011. doi: 10.2215/CJN.0058011
Calcium-sensing receptor and aquaporin 2 interplay in hypercalciuria-associated renal concentrating defect in humans. An in vivo and in vitro study.
Get PDFOne mechanism proposed for reducing the risk of calcium renal stones is activation of the calcium-sensing receptor (CaR) on the apical membranes of collecting duct principal cells by high luminal calcium. This would reduce the abundance of aquaporin-2 (AQP2) and in turn the rate of water reabsorption. While evidence in cells and in hypercalciuric animal models supports this hypothesis, the relevance of the interplay between the CaR and AQP2 in humans is not clear. This paper reports for the first time a detailed correlation between urinary AQP2 excretion under acute vasopressin action (DDAVP treatment) in hypercalciuric subjects and in parallel analyzes AQP2-CaR crosstalk in a mouse collecting duct cell line (MCD4) expressing endogenous and functional CaR. In normocalciurics, DDAVP administration resulted in a significant increase in AQP2 excretion paralleled by an increase in urinary osmolality indicating a physiological response to DDAVP. In contrast, in hypercalciurics, baseline AQP2 excretion was high and did not significantly increase after DDAVP. Moreover DDAVP treatment was accompanied by a less pronounced increase in urinary osmolality. These data indicate reduced urinary concentrating ability in response to vasopressin in hypercalciurics. Consistent with these results, biotinylation experiments in MCD4 cells revealed that membrane AQP2 expression in unstimulated cells exposed to CaR agonists was higher than in control cells and did not increase significantly in response to short term exposure to forskolin (FK). Interestingly, we found that CaR activation by specific agonists reduced the increase in cAMP and prevented any reduction in Rho activity in response to FK, two crucial pathways for AQP2 translocation. These data support the hypothesis that CaR-AQP2 interplay represents an internal renal defense to mitigate the effects of hypercalciuria on the risk of calcium precipitation during antidiuresis. This mechanism and possibly reduced medulla tonicity may explain the lower concentrating ability observed in hypercalciuric patients
LECTURAS DE PLINIO SOBRE TRES PROCESOS CONTRA MAGISTRADOS ROMANOS
No full textThis work assumes the importance of knowing the ancient Roman
criminal law through the use of literary sources because they help to have a more comprehensive view about the way they have operated crimes and crimes Roman antiquity. Under this idea, is to study the crime of extortion that may make administration officials through three letters written by Pliny the Younger in the early second century A.D. In them, the author provides information about this crime that goes beyond that provided for in the legal rules and interpretations of the jurists, both contained in the Digest, accounting for issues such as: the opinions and ratings that generated the commission these behaviors in society then existing conception and delivery of gifts to the rulers which is not always to be the compensation of wrongdoing
Reading of the letters of Pliny about three trials against roman magistrates
Get PDFEl presente trabajo asume la importancia de conocer el antiguo derecho penal romano a través del uso de fuentes literarias porque ellas ayudan a tener una visión más completa acerca de la forma en que se han desenvuelto los delitos y los crímenes en la antigüedad romana. Bajo esta idea, se pretende estudiar el crimen de extorsión que pueden cometer los oficiales de la administración a través de tres cartas escritas por Plinio el Joven a comienzos del siglo II d.C. En ellas, el autor aporta información sobre este crimen que va más allá de la prevista en las normas jurídicas y en las interpretaciones de los juristas, ambas contenidas en el Digesto, dando cuenta de cuestiones como: las opiniones y valoraciones que generaba la comisión de estas conductas en la sociedad de entonces y la concepción existente sobre la entrega de dádivas a los gobernantes la que no siempre resulta ser la compensación de un proceder ilícito.This work assumes the importance of knowing the ancient Roman criminal law through the use of literary sources because they help to have a more comprehensive view about the way they have operated crimes and crimes Roman antiquity. Under this idea, is to study the crime of extortion that may make administration officials through three letters written by Pliny the Younger in the early second century A.D. In them, the author provides information about this crime that goes beyond that provided for in the legal rules and interpretations of the jurists, both contained in the Digest, accounting for issues such as: the opinions and ratings that generated the commission these behaviors in society then existing conception and delivery of gifts to the rulers which is not always to be the compensation of wrongdoing.Ciencias ReligiosasDerech
Impaired urinary concentration ability is a sensitive predictor of renal disease progression in Joubert syndrome
Get PDFJoubert syndrome (JS) is an inherited ciliopathy characterized by a complex midbrain-hindbrain malformation and multiorgan involvement. Renal disease, mainly juvenile nephronophthisis (NPH), was reported in 25-30% patients although only ∼18% had a confirmed diagnosis of chronic kidney disease (CKD). NPH often remains asymptomatic for many years, resulting in delayed diagnosis. The aim of the study was to identify a biomarker able to quantify the risk of progressive CKD in young children with JS
Risk Factors for Cyclosporin A Nephrotoxicity in Children with Steroid-Dependant Nephrotic Syndrome
No full textEffect of ATP stimulation on AQP2 trafficking in MCD4 cells.
No full text<p>(A) MCD4 cells were preincubated with 100 µM ATP or used under control conditions and then stimulated with FK 10<sup>−4</sup> M. The amount of apical AQP2 was quantitated by apical surface biotinylation. ATP caused AQP2 membrane accumulation comparable to that found in FK treated cells. The total amount of AQP2 in the starting preparation was comparable in each experimental condition (total AQP2). (B) Densitometric analysis of the 29 kDa biotinylated AQP2 band. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0033145#s2" target="_blank">Results</a> are expressed as mean values ± S.E.M. The values obtained in three independent experiments are expressed as percentages of the basal condition. Data were compared by one-way Anova and Tukey's multiple comparison test (* P<0.05 relative to ctr.) (C) Immunolocalization of AQP2 and analysis by confocal microscopy. MCD4 cells were grown on permeable support to full confluence fixed and immunostained with antibodies against AQP2. In resting cells, AQP2 was mainly detectable in sub-apical vesicles (ctr). After FK treatment, AQP2 localized to the apical membrane (FK). A similar apical localization was observed in cells exposed to 5 mM calcium (Ca<sup>2+</sup>) or to NPS-R 568 (NPS R) or to ATP (ATP) treatments. By contrast, no AQP2 redistribution was observed after exposure to the inactive NPS enantiomer NPS-S (NPS-S).</p
Urinary osmolality during DDAVP test.
No full text<p>(A) Baseline and maximal urine osmolality after DDAVP test in normocalciuric and hypercalciuric patients. (B) Urinary osmolality in samples collected hourly after DDAVP administration. In hypercalciurics, DDAVP treatment was accompanied by a significantly lower increase in urinary osmolality, indicating a reduced urinary concentrating ability in response to vasopressin in hypercalciuric subjects. The values obtained were compared by one-way Anova and Tukey's multiple comparison test (*P<0.005, **P<0.001, ***P<0.0001.).</p
Measurements of intracellular cAMP levels.
No full text<p>MCD4 cells were treated with 5 mM Ca<sup>2+</sup>, 300 µM Gd<sup>3+</sup> or 10 µM NPS-R 568 for 30 minutes and then stimulated with FK 10<sup>−4</sup> M for 20 min at 37°C. Results are expressed as % of the value found in the indicated relative controls.</p>a<p>P<0.05 vs control.</p>b<p>P<0.05 vs forskolin.</p
