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Oxalate Concentrations (oxalate + concentration)
Selected AbstractsNuclear pore complex oxalate binding protein p62: Its expression on oxalate exposure to VERO cellsJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 6 2004P. Sivakamasundari Abstract Oxalate rich stones are the most common among the various stones. Oxalate binding protein plays a vital role in the transport of oxalate. Nuclear pore complex (NPC) contains a protein of molecular weight 62 kDa and it has maximum oxalate binding activity. The physiological significance of the presence of oxalate binding protein in the NPC is not well understood. In order to study its function, the expression of this protein during oxalate stress condition and the morphological changes on oxalate exposure to synchronized VERO cells have been determined. VERO cells were synchronized at different stages of cell cycle using cell cycle blockers and expression of the NPC p62 was assessed using enzyme linked immunosorbent assay (ELISA) technique with p62 antibody (MAb 414). Expression of NPC p62 was more pronounced in 1.0 mM oxalate concentration in mitotic phase than in S phase, suggesting cell cycle dependency. During oxalate exposure there is cell aggregation and complete degeneration of cell morphology occurs, which in turn lead to the expression of certain genes, including the NPC oxalate binding protein p62. Thus, oxalate induces degeneration of cells (may be due to the lipid peroxidation) and leads to the expression of NPC oxalate binding protein and the expression is of cell cycle dependent manner. © 2004 Wiley-Liss, Inc. [source] Changes in renal hemodynamics and urodynamics in rats with chronic hyperoxaluria and after acute oxalate infusion: Role of free radicalsNEUROUROLOGY AND URODYNAMICS, Issue 2 2003Ho-Shiang Huang Abstract Aims The aim of this study was to evaluate possible changes in renal hemodynamic and urodynamic parameters in rats with chronic hyperoxaluria and after acute oxalate challenge. We also evaluated the possible association between free radical (FR) production, hyperoxaluria, and calcium oxalate (CaOx) calculi formation. Methods Chronic hyperoxaluria was induced by adding 0.75% ethylene glycol (EG) to the drinking water of male Wistar rats. After 7, 21, and 42 days of treatment, urinary biochemistry, oxalate levels, and lipid peroxides were measured. Kidney calculi were examined by polarizing microscopy. In the second part of the experiments, 1, 10, 20, and 30 mg kg,1 hr,1 oxalate was infused, by means of an intrarenal arterial catheter (IRA), into normal rats sequentially. Superoxide dismutase (SOD) infusion by means of IRA, in addition to oxalate, was also performed to check its influence on the altered renal function after oxalate infusion. In both the acute and chronic groups, renal blood flow (RBF), cortical microvascular blood flow (CMVBF), glomerular filtration rate (GFR), urine flow (UV), and urinary sodium excretion (UNaV) were measured, and chemiluminescence (CL) was examined in the renal venous blood. Results Levels of urinary lipid peroxides and enzymuria had increased since day 7, and increased the size of numbers of CaOx crystals in the kidney were noted beginning on day 21, but elevated CL was detectable only on day 7 after 0.75% EG treatment. Decreased UV and UNaV were noted in the 42-day EG group, although the 24-hr creatinine clearance values were normal in all experimental groups. On the other hand, RBF, GFR, and CMVBF were attenuated with elevated FR when the oxalate concentration was higher than 10 mg kg,1 hr,1 in the acute oxalate infusion group. With SOD pretreatment, the decreased RBF, GFR, and CMVBF could be reversed at 10 mg kg,1 hr,1 of oxalate, and be partially reversed at 20. FR also could be reduced significantly at 10 and 20 mg kg,1 hr,1 of oxalate. Conclusions Decreased urine flow and sodium excretion were the main renal functions affected by chronic hyperoxaluria. However, that only the 42-day EG group had a decreased tubular function cannot be fully explained by the persistent tubular enzymuria and increased lipid peroxides that began on day 7 after EG treatment. With acute oxalate infusion, the major insult to renal function was renal hemodynamics. Pretreated SOD could reverse the attenuated hemodynamics and reduce the elevated FR partly, which suggested that FR is responsible for oxalate toxicity. Neurourol. Urodynam. 22:176,182, 2003. © 2003 Wiley-Liss, Inc. [source] Oxalate exudation into the root-tip water free space confers protection from aluminum toxicity and allows aluminum accumulation in the symplast in buckwheat (Fagopyrum esculentum)NEW PHYTOLOGIST, Issue 2 2010Benjamin Klug Summary ,A better understanding of aluminum (Al) uptake and transport is expected to contribute to unravel the apparent contradiction between Al exclusion and Al accumulation in buckwheat. ,We studied the effect of Al supply on the root-tip Al and oxalate concentrations of the apoplastic water free space fluid (WFSF) and the symplast as affected by temperature, oxalate supply and the anion-channel blocker phenylglyoxal (PG). ,Aluminum supply rapidly activated the release of oxalate to the WFSF to establish a 1 : 1 Al to oxalate ratio. In the symplast, the Al concentration was 100 times higher than in the external solution, and the Al to oxalate ratio was 1 : 2. Loading and unloading of Al, but not of oxalate, into and from the symplast were reduced at low temperature and are thus under metabolic control. Application of PG reduced the constitutive and the Al-enhanced WFSF oxalate concentrations and enhanced Al-induced root-growth inhibition. Unlike a 1 : 3 Al to oxalate ratio, a 1 : 1 ratio ameliorated only partly Al-induced root-growth inhibition without affecting root-tip Al contents or WFSF Al concentrations. ,We present a hypothesis with an Al oxalate (Ox)+ plasma-membrane transporter in the root cortex and a xylem-loading Al citrate (Cit)n, transporter in the xylem parenchyma cells as key elements of Al accumulation in buckwheat. [source] Determination of the Optimal Conditions for Synthesis of Silver Oxalate NanorodsCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 10 2008M. Pourmortazavi Abstract In this study, an orthogonal array design (OAD), OA9, was employed as a statistical experimental method for the controllable, simple and fast synthesis of silver oxalate nanorods. Ultrafine silver oxalate rods were synthesized by a precipitation method involving the addition of silver ion solution to the oxalate reagent. The effects of reaction conditions, i.e., silver and oxalate concentrations, flow rate of reagent addition and temperature, on the diameter of the synthesized silver oxalate rods were investigated. The effects of these factors on the width of the silver oxalate rods were quantitatively evaluated by the analysis of variance (ANOVA). The results showed that silver oxalate nanorods can be synthesized by controlling the silver concentration, flow rate and temperature. Finally, the optimum conditions for the synthesis of silver oxalate nanorods by this simple and fast method were proposed. The results of ANOVA showed that 0.001,mol/L silver ion concentration, 40,mL/min flow rate for the addition of the silver reagent to the oxalate solution and 0,°C temperature are the optimum conditions for producing silver oxalate nanorods with 107 ± 45,nm width. [source] | ||||||||||