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Uric Acid (uric + acid)
Kinds of Uric Acid Terms modified by Uric Acid Selected AbstractsPoly(pyridine-3-boronic acid)/Multiwalled Carbon Nanotubes Modified Glassy Carbon Electrodes for Simultaneous Determination of Ascorbic Acid, 3,4-Dihydroxyphenylacetic Acid and Uric AcidELECTROANALYSIS, Issue 19 2010Zhijiao Wu Abstract Poly(pyridine-3-boronic acid) (PPBA)/multiwalled carbon nanotubes (MWCNTs) composite modified glassy carbon electrode (GCE) was used for the simultaneous determination of ascorbic acid (AA), 3,4-dihydroxyphenylacetic acid (DOPAC) and uric acid (UA). The anodic peaks for AA, DOPAC and UA at the PPBA/MWCNTs/GCE were well resolved in phosphate buffer solution (pH,7.4). The electrooxidation of AA, DOPAC and UA in the mixture solution was investigated. The peak currents increase with their concentrations increasing. The detection limits (S/N=3) of AA, DOPAC and UA are 5,µM, 3,µM and 0.6,µM, respectively. [source] Simultaneous Determination of Ascorbic Acid, Dopamine and Uric Acid at Pt Nanoparticles Decorated Multiwall Carbon Nanotubes Modified GCEELECTROANALYSIS, Issue 10 2010Zekerya Dursun Abstract A modified electrode was fabricated by electrochemically deposition of Pt nanoparticles on the multiwall carbon nanotube covered glassy carbon electrode (Pt nanoparticles decorated MWCNT/GCE). A higher catalytic activity was obtained to electrocatalytic oxidation of ascorbic acid, dopamine, and uric acid due to the enhanced peak current and well-defined peak separations compared with both, bare and MWCNT/GCE. The electrode surfaces were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and electrochemical impedance spectroscopy (EIS). Individual and simultaneous determination of AA, DA, and UA were studied by differential pulse voltammetry. The detection limits were individually calculated for ascorbic acid, dopamine, and uric acid as being 1.9×10,5,M, 2.78×10,8,M, and 3.2×10,8,M, respectively. In simultaneous determination, LODs were calculated for AA, DA, and UA, as of 2×10,5,M, 4.83×10,8,M, and 3.5×10,7,M, respectively. [source] Silver Doped Poly(L -valine) Modified Glassy Carbon Electrode for the Simultaneous Determination of Uric Acid, Ascorbic Acid and DopamineELECTROANALYSIS, Issue 5 2010Wenna Hu Abstract In this paper, a silver doped poly(L -valine) (Ag-PLV) modified glassy carbon electrode (GCE) was fabricated through electrochemical immobilization and was used to electrochemically detect uric acid (UA), dopamine (DA) and ascorbic acid (AA) by linear sweep voltammetry. In pH,4.0 PBS, at a scan rate of 100,mV/s, the modified electrode gave three separated oxidation peaks at 591,mV, 399,mV and 161,mV for UA, DA and AA, respectively. The peak potential differences were 238,mV and 192,mV. The electrochemical behaviors of them at the modified electrode were explored in detail with cyclic voltammetry. Under the optimum conditions, the linear ranges were 3.0×10,7 to 1.0×10,5,M for UA, 5.0×10,7 to 1.0×10,5,M for DA and 1.0×10,5 to 1.0×10,3,M for AA, respectively. The method was successfully applied for simultaneous determination of UA, DA and AA in human urine samples. [source] Differential Pulse Voltammetric Determination of Uric Acid on Carbon-Coated Iron Nanoparticle Modified Glassy Carbon ElectrodesELECTROANALYSIS, Issue 10 2008Shengfu Wang Abstract A carbon-coated iron nanoparticles (CIN, a new style fullerence related nanomaterial) modified glassy carbon electrode (CIN/GCE) has been developed for the determination of uric acid (UA). Electrochemical behaviors of UA on CIN/GCE were explored by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). It was found that the voltammetric response of UA on CIN/GC was enhanced dramatically because of the strong accumulation effect of CIN and the large working area of the CIN/GC electrode. The parameters including the pH of supporting electrolyte, accumulation potential and time, that govern the analytical performance of UA have been studied and optimized. The DPV signal of UA on CIN/GCE increased linearly with its concentration in the range from 5.0×10,7 to 2.0×10,5 M, with a detection limit of 1.5×10,7 M (S/N=3). The CIN/GCE was used for the determination of UA in samples with satisfactory results. The proposed CIN/GCE electrochemical sensing platform holds great promise for simple, rapid, and accurate detection of UA. [source] Simultaneous Determination of Uric Acid and Ascorbic Acid Using Edge Plane Pyrolytic Graphite ElectrodesELECTROANALYSIS, Issue 8 2006Roohollah, Torabi Kachoosangi Abstract Edge plane pyrolytic graphite electrodes have been applied for the determination of uric acid and ascorbic acid. The separate determination of uric acid was found to produce three linear ranges from 100,nM to 3400,,M with a detection limit of 30,nM found to be possible. Uric acid detection was also explored in the presence of 200,,M ascorbic acid where a detection limit of 52,nM was found to be possible. The detection of ascorbic acid in the presence of uric acid was also explored over three linear ranges of ascorbic acid with a limit of detection of 80,nM. Last the simultaneous determination of both uric acid and ascorbic acid is investigated over the range 100,nM to 1000,,M where detection limits of 50,nM and 120,nM were obtained respectively. Analysis of uric acid in a growth tissue medium was found to be successful, confirming the applicability of the methodology to real matrices. This protocol is shown to provide low detection limits, easy handling (no electrode modification), good voltammetric peak separation of uric acid and ascorbic acid and a wide linear dynamic range. [source] Determination of Uric Acid in the Presence of Ascorbic Acid Using Poly(3,4-ethylenedioxythiophene)-Modified ElectrodesELECTROANALYSIS, Issue 24 2005Senthil Kumar, Shanmugam Abstract A poly(3,4-ethylenedioxythiophene) (PEDOT) modified glassy carbon electrode (GCE) was used to determine uric acid in the presence of ascorbic acid at physiological pH facilitating a peak potential separation of ascorbic acid and uric acid oxidation (ca. 365,mV), which is the largest value reported so far in the literature. Also, an analytical protocol involving differential pulse voltammetry has been developed using a microchip electrode for the determination of uric acid in the concentration range of 1 to 20,,M in presence of excess of ascorbic acid. [source] Diagnostic Implications of Uric Acid in Electroanalytical MeasurementsELECTROANALYSIS, Issue 14 2005Abstract Urate has a long history in clinical analysis and has served as an important diagnostic in a number of contexts. The increasing interest in metabolic syndrome has led to urate being used in combination with a number of other biomarkers in the assessment of cardiovascular risk. The traditional view of urate as principally an interferent in electrochemical measurement is now gradually being replaced with the realization that its measurement could serve as an invaluable secondary (if not primary) marker when monitoring conditions such as diabetes and heart disease. Rather than attempting to wholly exclude urate electrochemistry, many strategies are being developed that can integrate the urate signal within the device architecture such that a range of biomarkers can be sequentially assessed. The present review has sought to rationalize the clinical importance that urate measurements could hold in future diagnostic applications , particularly within near patient testing contexts. The technologies harnessed for its detection and also those previously employed for its removal are reviewed with the aim of highlighting how the seemingly contrasting approaches are evolving to aid the development of new sensing devices for clinical analysis. [source] Serum Uric Acid and Lipid Levels While Taking Topiramate for MigraineHEADACHE, Issue 7 2008Abdulkadir Koçer MD Objective., Topiramate (TPM) therapies for epilepsy or migraine are long-time therapies with unknown mechanisms and special side effects. TPM influences cholesterol (TC) and lipoprotein serum levels. In addition, TPM may cause uric acid (UA) stone formation. Material and Methods., Serum UA, TC, and triglyceride (TG) levels were measured in 53 migraine patients receiving TPM and in 44 age- and sex-matched controls. Compared with controls, patients on TPM showed significantly higher UA and nonsignificantly higher TC and TG values. We recorded pre- and posttreatment levels of UA, TC, and TG levels in 23 patients. Results., We found increased serum levels of UA with TPM use (P < .01). There was a significant and positive correlation between serum UA levels and male gender (P < .01). The changes in serum UA levels before and after TPM treatment differed significantly (P < .01). Conclusion., Our results suggest a need for monitoring serum UA levels in patients receiving TPM. We should perhaps prescribe a low-UA diet and advice to drink much more water in these patients. [source] Uric Acid as a Marker for Renal Dysfunction in Hypertensive Women on Diuretic and Nondiuretic TherapyJOURNAL OF CLINICAL HYPERTENSION, Issue 5 2009Rodolfo. Hyperuricemia is a common finding in hypertensive patients, especially among those who are on diuretic therapy. However, its clinical relevance regarding cardiovascular and chronic kidney disease (CKD) has not clearly been established. The authors assessed whether, in a population of 385 hypertensive women categorized according to diuretic therapy, the stratification in quartiles by uric acid levels would identify a gradient of changes in renal function and in risk factors for cardiovascular disease. The following were evaluated: serum uric acid, glycemia, total and fractional cholesterol, triglycerides, apolipoprotein (Apo) B, Apo A-I, and C-reactive protein. Renal function was assessed by serum creatinine, albuminuria, and estimated glomerular filtration rate (eGFR) by the Modification of Diet in Renal Disease equation, whereas cardiovascular risk was estimated through the Framingham score. A total of 246 women were on diuretic therapy; 139 were taking other antihypertensive medications. There was a reduction in eGFR parallel to the increase in uric acid levels, regardless of diuretic use and without a concomitant increase in albuminuria. In both groups, higher uric acid levels translated into an increase in metabolic syndrome components, in markers of insulin resistance, triglyceride/high-density lipoprotein levels, and Apo B/Apo A-I ratios, as well as in Framingham scores. Hyperuricemia was associated with an increase in inflammatory markers only in patients on diuretic therapy. In a binary logistic regression, hyperuricemia (uric acid >6.0 mg/dL) was independently associated with CKD (eGFR <60 mL/min/1.73 m˛) (odds ratio, 2.63; 95% confidence interval, 1.61,4.3; P<.001). In hypertensive women, the presence of hyperuricemia indicated a substantial degree of kidney dysfunction as well as a greater cardiovascular risk profile. [source] Serum Uric Acid as a Risk Factor for Cardiovascular and Renal Disease: An Old Controversy RevivedJOURNAL OF CLINICAL HYPERTENSION, Issue 7 2006Francesca Viazzi MD Hyperuricemia is commonly associated with traditional risk factors such as abnormalities in glucose metabolism, dyslipidemia, and hypertension. Recent studies have revived the controversy over the role of serum uric acid as an independent prognostic factor for cardiovascular mortality. The authors review clinical and experimental evidence concerning the role of serum uric acid in the development of cardiovascular and renal damage. Results of trials suggesting that serum uric acid variations over time may have a prognostic impact are also discussed. [source] Level of Superoxide Dismutase, Glutathione Peroxidase and Uric Acid in Thioacetamide-Induced Cirrhotic RatsANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 2 2002H. ABUL Levels of superoxide dismutase and glutathione peroxidase were determined in blood and hepatic tissues of thioacetamide-induced cirrhotic rats and compared to levels in age-matched control animals. The plasma level of uric acid was also determined in these animals. A general decrease was noticed in the level of all the antioxidants examined as compared to the control. This decrease was statistically significant in the level of all the antioxidants studied, except for the level of superoxide dismutase in blood. A decrease in the antioxidant level may indicate an increase in free radical level and thereby an increase in cellular damage in cirrhotic rats. The changes in the level of antioxidants showed a direct correlation with the changes in the level of trace elements observed in our previous studies. These studies suggest that antioxidants alone or in combination with trace elements may have beneficial effects in treating liver cirrhosis. [source] Selective Voltammetric Determination of Uric Acid in the Presence of Ascorbic Acid at Ordered Mesoporous Carbon Modified ElectrodesCHINESE JOURNAL OF CHEMISTRY, Issue 6 2008Yan-Li WEN Abstract A novel chemically modified electrode was fabricated by immobilizing ordered mesoporous carbon (OMC) onto a glassy carbon (GC) electrode. The electrocatalytic behavior of the OMC modified electrode towards the oxidation of uric acid (UA) and ascorbic acid (AA) was studied. Compared to a glassy carbon electrode, the OMC modified electrode showed a faster electron transfer rate and reduced the overpotentials greatly. Furthermore, the OMC modified electrode resolved the overlapping voltammetric responses of UA and AA into two well-defined voltammetric peaks with peak separation of ca. 0.38 V. All results show that the OMC modified electrode has a good electrocatalytic ability to UA and AA, and has an excellent response towards UA even in the presence of high concentration AA. [source] Effect of sunlight exposure and aging on skin surface lipids and urateEXPERIMENTAL DERMATOLOGY, Issue 2003Nobumasa Hayashi Abstract Free fatty acids (FFA), squalene, squalene hydroperoxide, and uric acid in the methanol extracts from human skin surface were measured. Levels of FFA and squalene were significantly lower in the older (83.7 ± 9.4 years) than in the younger (22.2 ± 3.9 years) group. FFA are mostly saturated, and linoleic acid is an exclusive polyunsaturated fatty acid. The composition of linoleic acid decreased in the older group by 40%, suggesting age-dependent loss of oxidatively vulnerable polyunsaturated fatty acid. Even monounsaturated acids such as palmitoleic and oleic acids decreased significantly in the older group. This could be interesting because 2-nonenal is the oxidation product of palmitoleic acid and has been identified as the major aged body odor component. Sunlight exposure for 1.5 h did not change levels of FFA and squalene, or FFA composition. However, squalene hydroperoxide increased by 60-fold, as reported previously, suggesting that hydroperoxide is produced by singlet oxygen. Uric acid increased by two-fold, which may be the adaptive response against photo-oxidative stress because uric acid is a good scavenger of singlet oxygen and oxygen radicals. [source] Astroglia-mediated effects of uric acid to protect spinal cord neurons from glutamate toxicityGLIA, Issue 5 2007Yangzhou Du Abstract Uric acid (UA) has been demonstrated to reduce damage to neurons elicited by oxidative stress. However, our studies utilizing cultures derived from embryonic rat spinal cord indicate that an astroglia-mediated mechanism is involved in the effects of UA to protect neurons from glutamate toxicity. The damage elicted by glutamate to neurons in a mixed culture of spinal cord cells can be reversed by UA. Furthermore, addition of UA after the termination of glutamate exposure suggests that UA plays an active role in mediating neuroprotection rather than purely binding peroxynitrite, as previously thought. Importantly, in pure neuron cultures from the same tissue, UA does not protect against glutamate toxicity. Addition of astroglia to the pure neuron cultures restores the ability of UA to protect the neurons from glutamate-induced toxicity. Our results also suggest that glia provide EAAT-1 and EAAT-2 glutamate transporters to protect neurons from glutamate, that functional EAATs may be necessary to mediate the effects of UA, and that treatment with UA results in upregulation of EAAT-1 protein. Taken together, our data strongly suggest that astroglia in mixed cultures are essential for mediating the effects of UA, revealing a novel mechanism by which UA, a naturally produced substance in the body, may act to protect neurons from damage during insults such as spinal cord injury. © 2007 Wiley-Liss, Inc. [source] Role of uric acid in different types of calcium oxalate renal calculiINTERNATIONAL JOURNAL OF UROLOGY, Issue 3 2006FÉLIX GRASES Aim:, The presence of uric acid in the beginning zone of different types of ,pure' calcium oxalate renal calculi was evaluated with the aim of establishing the degree of participation of uric acid crystals in the formation of such calculi. Methods:, The core or fragment of different types of ,pure' calcium oxalate renal calculi was detached, pulverized and uric acid extracted. Uric acid was determined using a high-performance liquid chromatography/mass spectrometry method. Results:, In calcium oxalate monohydrate (COM) papillary calculi with a core constituted by COM crystals and organic matter, 0.030 ± 0.007% uric acid was found in the core. In COM papillary calculi with a core constituted by hydroxyapatite, 0.031 ± 0.008% uric acid was found in the core. In COM unattached calculi (formed in renal cavities) with the core mainly formed by COM crystals and organic matter, 0.24 ± 0.09% uric acid was found in the core. In COM unattached calculi with the core formed by uric acid identifiable by scanning electron microscopy (SEM) coupled to X-ray microanalysis, 20.8 ± 7.8% uric acid was found in the core. In calcium oxalate dihydrate (COD) unattached calculi containing little amounts of organic matter, 0.012 ± 0.004% uric acid was found. In COD unattached calculi containing little amounts of organic matter and hydroxyapatite, 0.0030 ± 0.0004% of uric acid was found. Conclusions:, From these results it can be deduced that uric acid can play an important role as inducer (heterogeneous nucleant) of COM unattached calculi with the core formed by uric acid identifiable by SEM coupled to X-ray microanalysis (these calculi constitute the 1.2% of all calculi) and in COM unattached calculi with the core mainly formed by COM crystals and organic matter (these calculi constitute the 10.8% of all calculi). [source] The relationship between uric acid levels and Huntington's disease progression,MOVEMENT DISORDERS, Issue 2 2010Peggy Auinger MS Abstract Uric acid (UA) may be associated with the progression of Parkinson's disease and related neurodegenerative conditions; however, its association with Huntington's disease (HD) progression has not been explored. A secondary analysis of 347 subjects from the CARE-HD clinical trial was performed to examine the relationship between baseline UA levels and the level of functional decline in HD. Outcomes included change in scores at 30 months for the Unified Huntington's Disease Rating Scale components. There was less worsening of total functional capacity over time with increasing baseline UA levels (adjusted mean worsening in scores: 3.17, 2.99, 2.95, 2.28, 2.21, from lowest to highest UA quintile, P = 0.03). These data suggest a possible association between higher UA levels and slower HD progression, particularly as measured by total functional capacity. If confirmed, UA could be an important predictor and potentially modifiable factor affecting the rate of HD progression. © 2009 Movement Disorder Society [source] Uric acid in Parkinson's diseaseMOVEMENT DISORDERS, Issue 12 2008Ilana Schlesinger MD Abstract Recent studies have provided evidence that uric acid may play a role in the development and progression of Parkinson's disease (PD). Uric acid is a natural antioxidant that may reduce oxidative stress, a mechanism thought to play a role in the pathogenesis of PD. Higher levels of serum urate (SU) may have a neuroprotective effect. High SU levels reduced the risk of developing PD and correlated with slower PD progression. Among PD patients SU levels were lower as compared with controls. The manipulation of SU levels holds promise in the treatment of PD. It is possible that a high purine diet in patients with PD may slow progression of the disease. Milk and meat consumption as well as exercise modify the risk of developing PD possibly through their influence on SU levels. In this article, we review the association between PD and SU levels and its implication on the management of PD. © 2008 Movement Disorder Society [source] Uric acid , A bad acid for the kidney?PEDIATRIC TRANSPLANTATION, Issue 8 2008Vikas R. Dharnidharka No abstract is available for this article. [source] Determination of uric acid concentrations in human tear fluid, aqueous humour and serumACTA OPHTHALMOLOGICA, Issue 2 2009Jutta Horwath-Winter Abstract. Purpose:, The aim of this investigation was to assess and compare levels of uric acid in human tear fluid, aqueous humour and serum in cataract patients in order to obtain information about uric acid-dependent antioxidative status. Methods:, Reflex tear fluid, aqueous humour and serum were obtained from 103 cataract patients (52 women, 51 men). Uric acid was determined by a reversed phase chromatographic method with electrochemical detection. The Randox test was used to measure the contribution of uric acid to the total antioxidative status (TAS) of these body fluids. Results:, Mean concentrations of uric acid were 20 ± 8 ,g/ml in tear fluid, 18 ± 6 ,g/ml in aqueous humour and 58 ± 15 ,g/ml in serum. Significantly less uric acid was found in tear fluid (p < 0.01) and aqueous humour (p < 0.01) in female cataract patients compared with male cataract patients. There was a significant positive correlation between uric acid content in tear fluid, aqueous humour and serum, respectively (p < 0.01). The contribution of uric acid to TAS (Randox test) amounted to 38% in tear fluid, 10% in aqueous humour and 37% in serum. Conclusions:, Uric acid was found in comparable amounts in tear fluid and aqueous humour, but these were two- to threefold lower than in serum. Female cataract patients had lower uric acid values in tear fluid and aqueous humour compared with male cataract patients. Uric acid is an important antioxidant, as proven by its contribution to TAS as determined by the Randox test. The precise role of uric acid in the antioxidative reactions in tear fluid and aqueous humour is still under debate. [source] High total antioxidant activity and uric acid in tracheobronchial aspirate fluid of preterm infants during oxidative stress: an adaptive response to hyperoxia?ACTA PAEDIATRICA, Issue 3 2000G Vento The effect of O2 exposure, expressed by mean daily fractional inspired oxygen concentration (FiO2), was evaluated during the first 6 d of life in the tracheobronchial aspirate fluid of 16 mechanically ventilated preterm infants in terms of both antioxidant response and oxidative damage, by measuring total antioxidant activity, uric acid concentrations and protein carbonyl content. Each day linear regression analysis was performed and a positive correlation was found between total antioxidant activity and FiO2 during the study period, especially on day 2 of life (r= 0.91, p < 0.0001), but uric acid correlated only in the first 3 d, especially on the 2nd day (r= 0.83, p < 0.0001). No correlation was found between carbonyl content and FiO2. The highest values of total antioxidant activity (416 and 790 ,mol l,1) were found in 2 babies ventilated with highest FiO2: 1 and 0.80, respectively. Total antioxidant activity was not detectable or was very low in the babies not requiring O2 therapy. The highest value of uric acid (270 ,mol l,1) was found in the baby ventilated with 100% oxygen. Uric acid concentrations obtained in these babies were much higher then those reported in the bronchoalveolar lavage fluid of adults. Preterm babies seem to have an antioxidant response in the tracheobronchial aspirate fluid following an oxidative stress and uric acid may be physiologically important as an antioxidant of the respiratory tract, especially during the first days of life. [source] Assessment of endothelial function and blood metabolite status following acute ingestion of a fructose-containing beverageACTA PHYSIOLOGICA, Issue 1 2010A. J. Bidwell Abstract Aim:, Fructose intake has increased concurrent with sugar intake and this increase has been implicated in contributing to the development of metabolic syndrome risk factors. Recent evidence suggests a role for uric acid (UA) as a potential mediator via suppression of nitric oxide (NO) bioavailability. The aim of this study was to explore this hypothesis by measuring changes in UA concentration and systemic NO bioavailability as well as endothelial function in response to acute ingestion of a glucose-fructose beverage. Methods:, Ten young (26.80 ± 4.80 years), non-obese (body mass index: 25.1 ± 2.55 kg m,2; percent body fat: 13.5 ± 6.9%) male subjects ingested either a glucose (100 g dextrose in 300 mL) or isocaloric glucose-fructose (glucose : fructose; 45 : 55 g in 300 mL) beverage. Blood was sampled pre- and every 15-min post-ingestion per 90 min and assayed for glucose, lactate, fructose, total nitrate/nitrate, UA and blood lipids. Forearm blood flow and pulse-wave velocity were recorded prior to and at 30 and 45 min time intervals post-ingestion, respectively, while heart rate, systolic and diastolic blood pressure were recorded every 15 min. Results:, The glucose-fructose ingestion was associated with a significant (P < 0.05) increase in plasma lactate concentration and altered free fatty acid levels when compared with glucose-only ingestion. However, UA was not significantly different (P = 0.08) between conditions (AUC: ,1018 ± 1675 vs. 2171 ± 1270 ,mol L,1 per 90 min for glucose and glucose-fructose conditions respectively). Consequently, no significant (P < 0.05) difference in endothelial function or systemic NO bioavailability was observed. Conclusion:, Acute consumption of a fructose-containing beverage was not associated with significantly altered UA concentration, endothelial function or systemic NO bioavailability. [source] Serum and 24-hour Urine Analysis in Adult Cyanotic and Noncyanotic Congenital Heart Disease PatientsCONGENITAL HEART DISEASE, Issue 3 2009Efrén Martínez-Quintana MD ABSTRACT Introduction., Glomerulopathy is a complication of congenital heart disease patients. The risk of developing renal impairment is particularly high in cyanotic patients. Objective., The aim of this study was to determine the prevalence of renal dysfunction and microalbumiuria in adult cyanotic and non cyanotic congenital heart disease patients. Methods., Fourteen cyanotic and 22 noncyanotic congenital heart disease patients were studied in the Adult Congenital Heart Disease Unit at the Complejo Hospitalario Universitario Insular-Materno Infantil. Demographic characteristics, complete blood count, and 24-hour urianalysis were obtained, including abdominal ultrasound in those with cyanosis. Results., No differences were seen between age (years) (27.4 ± 8.2; 26.4 ± 8.3; P = .71), sex, size, weight, or glomerular filtration rate (mL/min/1.73 m2) (81.1 ± 22.9 vs. 84.9 ± 9.2, P = .482) between cyanotic and noncyanotic patients. However, Eisenmenger patients had significantly impaired renal function when compared with noncyanotic patients (73.0 ± 17.3 vs. 84.9 ± 9.2 mL/min/1.73 m2, P = .023). Significant differences were obtained in oxygen saturation (%) (83.8 ± 5.8 vs. 97.8 ± 0.8; P = .000), hematocrit (%) (59.3 ± 8.1 vs. 40.9 ± 8.5; P = .000), platelets (103/µL) (161.5 ± 70.5 vs. 277.9 ± 57.6; P = .000), serum uric acid (mg/dL) (7.5 ± 2.3 vs. 5.6 ± 1.5; P = .008) and microalbuminuria (mg/24 hours) (12.8 [0, 700.2] vs. 2.4 [0, 18.9]; P = .000) between cyanotic and noncyanotic patients. Five cyanotic patients (35.7%) had microalbuminuria (>30 mg/24 hours) and three of them (21.4%) proteinuria (>1 g/24 hours). No significant differences were seen between serum and urine parameters between cyanotic patients who had microalbuminuria (>30 mg/24 hours) and those cyanotic patients who did not have it (<30 mg/24 hours). Conclusions., Renal impairment is frequently seen in congenital heart disease patients, being associated occasionally with proteinuria and microalbuminuria in cyanotic ones. [source] Effect of a nutritional liquid supplement designed for the patient with diabetes mellitus (Glucerna SR) on the postprandial glucose state, insulin secretion and insulin sensitivity in healthy subjectsDIABETES OBESITY & METABOLISM, Issue 3 2006M. González-Ortiz Aim:, To identify the effect of a nutritional liquid supplement designed for the patient with diabetes mellitus (Glucerna SR) in single administration on the postprandial glucose state, insulin secretion and insulin sensitivity in healthy subjects. Methods:, A randomized, single-blind, cross-over, clinical trial was carried out in 14 young, healthy, non-obese, volunteers. A basal metabolic profile, which included glucose level, insulin, total cholesterol, high-density lipoprotein and low-density lipoprotein cholesterol, triglycerides, creatinine, and uric acid, was measured. Subjects received a single administration of 300 kcal, gauged with water at 350 ml, of each of the following (at least 3 days apart): glucose 75 g, polymeric supplement (Ensure high calcium) 315 ml or Glucerna SR 323 ml. At the beginning of each administration and 30, 60, 90 and 120 min later, glucose and insulin concentrations were measured. Areas under the curve of glucose and insulin were calculated. First-phase and total insulin secretions and insulin sensitivity were also estimated. Results:, Glucose level at 120 min was significantly lower after receiving Ensure high calcium or Glucerna SR. Administration of Glucerna SR resulted in a significant reduction in the areas under the curve of glucose and insulin, as well as in total insulin secretion with a tendency to be lower in their first phase. Insulin sensitivity was increased. Conclusions:, A single administration of Glucerna SR to healthy subjects decreased the postprandial glucose and insulin states, as well as the insulin secretion; insulin sensitivity increased. [source] Caste-specific N and C isotope ratios in fungus-growing termites with special reference to uric acid preservation and their nutritional interpretationECOLOGICAL ENTOMOLOGY, Issue 3 2002I. Tayasu Abstract 1. Nitrogen and carbon isotope ratios and uric acid concentrations in fungus-growing termites (Isoptera: Termitidae: Macrotermitinae), sampled in Cameroon and Thailand, were determined in order to compare castes that are known to differ in behaviour and feeding habits. 2. Nitrogen isotope ratios (,15N) were either not significantly changed or lower in workers compared with the diet (the fungus combs), whereas carbon isotope ratios (,13C) were higher in worker termites than in the fungus combs. 3. In old workers, ,15N values were unexpectedly low and correlated negatively with whole-body uric acid concentrations. This indicates that older workers retain uric acid, which has a low ,15N value, to conserve nitrogen within the colony and, furthermore, that older colony members may ultimately be consumed by younger conspecifics. [source] Poly(pyridine-3-boronic acid)/Multiwalled Carbon Nanotubes Modified Glassy Carbon Electrodes for Simultaneous Determination of Ascorbic Acid, 3,4-Dihydroxyphenylacetic Acid and Uric AcidELECTROANALYSIS, Issue 19 2010Zhijiao Wu Abstract Poly(pyridine-3-boronic acid) (PPBA)/multiwalled carbon nanotubes (MWCNTs) composite modified glassy carbon electrode (GCE) was used for the simultaneous determination of ascorbic acid (AA), 3,4-dihydroxyphenylacetic acid (DOPAC) and uric acid (UA). The anodic peaks for AA, DOPAC and UA at the PPBA/MWCNTs/GCE were well resolved in phosphate buffer solution (pH,7.4). The electrooxidation of AA, DOPAC and UA in the mixture solution was investigated. The peak currents increase with their concentrations increasing. The detection limits (S/N=3) of AA, DOPAC and UA are 5,µM, 3,µM and 0.6,µM, respectively. [source] Simultaneous Determination of Ascorbic Acid, Dopamine and Uric Acid at Pt Nanoparticles Decorated Multiwall Carbon Nanotubes Modified GCEELECTROANALYSIS, Issue 10 2010Zekerya Dursun Abstract A modified electrode was fabricated by electrochemically deposition of Pt nanoparticles on the multiwall carbon nanotube covered glassy carbon electrode (Pt nanoparticles decorated MWCNT/GCE). A higher catalytic activity was obtained to electrocatalytic oxidation of ascorbic acid, dopamine, and uric acid due to the enhanced peak current and well-defined peak separations compared with both, bare and MWCNT/GCE. The electrode surfaces were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and electrochemical impedance spectroscopy (EIS). Individual and simultaneous determination of AA, DA, and UA were studied by differential pulse voltammetry. The detection limits were individually calculated for ascorbic acid, dopamine, and uric acid as being 1.9×10,5,M, 2.78×10,8,M, and 3.2×10,8,M, respectively. In simultaneous determination, LODs were calculated for AA, DA, and UA, as of 2×10,5,M, 4.83×10,8,M, and 3.5×10,7,M, respectively. [source] Silver Doped Poly(L -valine) Modified Glassy Carbon Electrode for the Simultaneous Determination of Uric Acid, Ascorbic Acid and DopamineELECTROANALYSIS, Issue 5 2010Wenna Hu Abstract In this paper, a silver doped poly(L -valine) (Ag-PLV) modified glassy carbon electrode (GCE) was fabricated through electrochemical immobilization and was used to electrochemically detect uric acid (UA), dopamine (DA) and ascorbic acid (AA) by linear sweep voltammetry. In pH,4.0 PBS, at a scan rate of 100,mV/s, the modified electrode gave three separated oxidation peaks at 591,mV, 399,mV and 161,mV for UA, DA and AA, respectively. The peak potential differences were 238,mV and 192,mV. The electrochemical behaviors of them at the modified electrode were explored in detail with cyclic voltammetry. Under the optimum conditions, the linear ranges were 3.0×10,7 to 1.0×10,5,M for UA, 5.0×10,7 to 1.0×10,5,M for DA and 1.0×10,5 to 1.0×10,3,M for AA, respectively. The method was successfully applied for simultaneous determination of UA, DA and AA in human urine samples. [source] Glassy Carbon Electrodes Modified with Multiwall Carbon Nanotubes Dispersed in PolylysineELECTROANALYSIS, Issue 15 2008Yamile Jalit Abstract We report the analytical performance of glassy carbon electrodes (GCE) modified with a dispersion of multiwall carbon nanotubes (MWCNT) in polylysine (Plys) (GCE/MWCNT-Plys). The resulting electrodes show an excellent electrocatalytic activity towards different bioanalytes like ascorbic acid, uric acid and hydrogen peroxide, with important decrease in their oxidation overvoltages. The dispersion of 1.0,mg/mL MWCNT in 1.0,mg/mL polylysine is highly stable, since after 2 weeks the sensitivity for hydrogen peroxide at GCE modified with this dispersion remained in a 90% of the original value. The MWCNT-Plys layer immobilized on glassy carbon electrodes has been also used as a platform to build supramolecular architectures by self-assembling of polyelectrolytes based on the polycationic nature of the polylysine used to disperse the nanotubes. The self-assembling of glucose oxidase has allowed us to obtain a supramolecular multistructure for glucose biosensing. The influence of glucose oxidase concentration and adsorption time as well as the effect of using polylysine or MWCNT-Plys as polycationic layers for further adsorption of GOx is also evaluated. [source] Differential Pulse Voltammetric Determination of Uric Acid on Carbon-Coated Iron Nanoparticle Modified Glassy Carbon ElectrodesELECTROANALYSIS, Issue 10 2008Shengfu Wang Abstract A carbon-coated iron nanoparticles (CIN, a new style fullerence related nanomaterial) modified glassy carbon electrode (CIN/GCE) has been developed for the determination of uric acid (UA). Electrochemical behaviors of UA on CIN/GCE were explored by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). It was found that the voltammetric response of UA on CIN/GC was enhanced dramatically because of the strong accumulation effect of CIN and the large working area of the CIN/GC electrode. The parameters including the pH of supporting electrolyte, accumulation potential and time, that govern the analytical performance of UA have been studied and optimized. The DPV signal of UA on CIN/GCE increased linearly with its concentration in the range from 5.0×10,7 to 2.0×10,5 M, with a detection limit of 1.5×10,7 M (S/N=3). The CIN/GCE was used for the determination of UA in samples with satisfactory results. The proposed CIN/GCE electrochemical sensing platform holds great promise for simple, rapid, and accurate detection of UA. [source] Electrocatalysis and Amperometric Detection of the Reduced Form of Nicotinamide Adenine Dinucleotide at Toluidine Blue/Zinc Oxide Coated ElectrodesELECTROANALYSIS, Issue 18 2007Ashok Kumar Abstract Thin toluidine blue (TBO) and zinc oxide (ZnO) hybrid films have been grown on glassy carbon electrode (GCE) and indium tin oxide coated (SnO2) glass electrodes by using cyclic voltammetry (CV). Scanning electron microscopy (SEM) images revealed spherical and beads-like shape of highly oriented TBO/ZnO hybrid films. Energy dispersive spectrometry (EDS) results declared that the films composed mainly of Zn and O. Moreover, TBO/ZnO hybrid films modified electrode is electrochemically active, dye molecules were not easily leached out from the ZnO matrix and the hybrid films can be considered for potential applications as sensor for amperometric determination of reduced nicotinamide adenine dinucleotide (NADH) at 0.0,V. A linear correlation between electrocatalytic current and NADH concentration was found to be in the range between 25,,M and 100,,M in phosphate buffer. In addition, we observed that dopamine, ascorbic acid and uric acid are not interference in amperometric detection of NADH in this proposed method. In addition, TBO/ZnO hybrid film modified electrode was highly stable and its response to the NADH also remained relentless. [source] | |||||||||||||||||||||||||||||||||||||