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1

Creatinine, urea, uric acid, water and electrolytes renal handling in the healthy oldest old  

PubMed Central

Renal physiology in the healthy oldest old has the following characteristics, in comparison with the renal physiology in the young: a reduced creatinine clearance, tubular pattern of creatinine back-filtration, preserved proximal tubule sodium reabsorption and uric acid secretion, reduced sodium reabsorption in the thick ascending loop of Henle, reduced free water clearance, increased urea excretion, presence of medulla hypotonicity, reduced urinary dilution and concentration capabilities, and finally a reduced collecting tubules response to furosemide which expresses a reduced potassium excretion in this segment due to a sort of aldosterone resistance. All physiological changes of the aged kidney are the same in both genders.

Musso, Carlos Guido; Alvarez Gregori, Joaquin; Jauregui, Jose Ricardo; Macias Nunez, Juan Florencio

2012-01-01

2

Plasma urea, creatinine and uric acid concentrations in relation to feeding in peregrine falcons (Falco peregrinus)  

Microsoft Academic Search

Significant post?prandial increases in plasma uric acid and plasma urea concentrations were observed in peregrine falcons. Post?prandial uric acid concentrations were similar to those in birds suffering from hyperuricaemia and gout and were well above the theoretical limit of solubility of sodium urate in plasma. It is not clear why under normal circumstances no urate deposits occur in peregrine falcons

J. T. Lumeij; J. D. Remple

1991-01-01

3

Urea, creatinine, uric acid, and phosphate spaces and their relationship to total body water during chronic hemodialysis  

SciTech Connect

The authors determined total body water (TBW) with tritium in 11 patients on chronic hemodialysis and compared this space to that estimated by 60% of body weight, and removal spaces of urea, creatinine, uric acid, and phosphate (PO4). The latter spaces were determined by dividing the total amount of substance (measured in total dialysate) by pre- minus post-dialysis concentrations. Body water X 0.6 was more than 10% less than the tritium space, and showed a maximal variation of 10 liters, or 24%. The removal space of urea was 80% of the tritium space, but correlated closely with it. The difference between total body water and urea removal space was variable and dependent on fluid excess (edema) in the patients. Creatinine, uric acid, and phosphate removal spaces were highly variable and not correlated to total body water. The authors suggest that actual measured TBW should be used, rather than estimations using BW X 0.6, for V in K X T/V, where K = clearance, T = duration of dialysis, and V = the removal space of urea. Furthermore, one may need to introduce a correction factor for urea removal space over TBW in the equation to allow better quantification of dialysis in edematous patients and during very fast dialyses.

Ericsson, F.; Odar-Cederloef, I.E.; Eriksson, C.G.; Lindgren, S.; Kjellstrand, C.M.

1988-07-01

4

Uric acid and urea in human sweat.  

PubMed

The present study investigated whether thermal sweating may relieve elevated concentrations of serum uric acid or urea. Concentrations of uric acid and urea were measured in the sweat of sixteen male volunteers, who were treated with external heat after one hour of intense physical exercise. The same analytes were also measured in their urine and serum samples. Furthermore, creatinine and some electrolytes were determined in these specimens. The results show that the concentration of uric acid in the sweat is 24.5 micromol/L, which is only 6.3% of that in serum. The concentration of urea in the sweat is 22.2 mmol/L, which is 3.6 times that in serum. The results indicate that sweat uric acid concentration is quite minimal, and the estimated total uric acid excretion per day in normal physiological range is insignificant. However, the level of sweat urea was found at a much higher concentration than the serum level. No correlation could be established between the level of uric acid in sweat and in serum. There was also no correlation between the level of urea in sweat and that in serum. These results suggest it would not be effective to relieve the elevated serum uric acid concentration by thermal sweating when the renal excretion of uric acid is partly compromised. Nevertheless, the potential of urea excretion via profuse sweating is apparent particularly when the kidneys are damaged or their function is impaired. These findings also suggest that persons who take vigorous exercise or are exposed to hot environments should be well advised to drink adequate fluids since heavy sweating excretes only minimal uric acid, accompanied by significant diminution of urinary output and diminished urinary excretions of uric acid, which may induce elevated levels of serum uric acid. PMID:12817713

Huang, Chien-Tsai; Chen, Mei-Lien; Huang, Li-Ling; Mao, I-Fang

2002-09-30

5

Prognostic Significance of Serum Creatinine and Uric Acid in Older Chinese Patients With Isolated Systolic Hypertension  

Microsoft Academic Search

We examined the relation of serum creatinine and uric acid to mortality and cardiovascular disease in older (aged $60 years) Chinese patients with isolated systolic hypertension (systolic\\/diastolic blood pressure $160\\/ ,95 mm Hg). We used Cox regression to correlate outcome with baseline serum creatinine and uric acid measured in 1880 and 1873, respectively, of the 2394 patients enrolled in the

Ji-Guang Wang; Jan A. Staessen; Robert H. Fagard; Willem H. Birkenhäger; Lansheng Gong; Lisheng Liu

2010-01-01

6

Suitable potentiometric enzyme sensors for urea and creatinine.  

PubMed

Enzyme sensors for urea and creatinine were developed by coupling an ammonia gas-diffusion electrode with triacetate cellulose membranes entrapping urease or creatinine deiminase enzymes. Satisfactory results were obtained by using these sensors both in standard solutions and in authentic biological matrices. PMID:2393088

Campanella, L; Sammartino, M P; Tomassetti, M

1990-06-01

7

Determination of orotic acid, uric acid, and creatinine in milk by liquid chromatography.  

PubMed

A simultaneous determination of orotic acid, uric acid, and creatinine in milk is described. Following deproteinization, the sample was analyzed by reversed-phase liquid chromatography, using a highly aqueous cationic ion-pair eluent and photodiode array UV detection. In view of their potential dietary significance, the validated method was applied to survey the influence of species, season, and lactation on their contribution to the nonprotein nitrogen pool in milk. Mature bovine milk contained orotic acid, uric acid, and creatinine in the range of 30-70, 9-24, and 6-12 microg/mL, respectively. Although uric acid and creatinine were present in all milks, orotic acid was essentially absent in nonruminant milks. In contrast to urate and creatinine, expression of orotic acid in bovine milk was strongly dependent on stage of early lactation. The co-existence in mammalian milks of related nucleoside and nucleotide components was also determined. PMID:15084094

Indyk, Harvey E; Woollard, David C

2004-01-01

8

Automated monosegmented flow analyser. Determination of glucose, creatinine and urea.  

PubMed

An automated monosegmented flow analyser containing a sampling valve and a reagent addition module and employing a laboratory-made photodiode array spectrophotometer as detection system is described. The instrument was controlled by a 386SX IBM compatible microcomputer through an IC8255 parallel port that communicates with the interface which controls the sampling valve and reagent addition module. The spectrophotometer was controlled by the same microcomputer through an RS232 serial standard interface. The software for the instrument was written in QuickBasic 4.5. Opto-switches were employed to detect the air bubbles limiting the monosegment, allowing precise sample localisation for reagent addition and signal reading. The main characteristics of the analyser are low reagent consumption and high sensitivity which is independent of the sample volume. The instrument was designed to determine glucose, creatinine or urea in blood plasma and serum without hardware modification. The results were compared against those obtained by the Clinical Hospital of UNICAMP using commercial analysers. Correlation coefficients among the methods were 0.997, 0.982 and 0.996 for glucose, creatinine and urea, respectively. PMID:9463952

Raimundo Júnior, I M; Pasquini, C

1997-10-01

9

Integrated microfluidic system for the simultaneous determination of ammonia, creatinine, and urea  

Microsoft Academic Search

An integrated sensing system for ammonia, creatinine, and urea incorporated in a micro-flow channel was microfabricated. The transducers for these sensors were air-gap Severinghaus-type ammonia sensors. The air gap was formed between the electrolyte solution for the ammonia sensor and sample solution. Creatinine demiminase and urease were immobilized at the bottom of the flow channel facing the indicator electrodes for

Hiroaki Suzuki; Yasuaki Matsugi

2005-01-01

10

Very fast electrophoretic determination of creatinine and uric acid in human urine using a combination of two capillaries with different internal diameters.  

PubMed

A capillary system formed by combining 25 and 100 ?m id capillaries was used in the short-end injection mode to determine creatinine and uric acid in human urine. The separation was performed at an electric field intensity of 2.3 kV/cm. Creatinine was determined in a BGE with a composition of 20 mM citric acid/NaOH (pH 3.0), and uric acid was determined in 20 mM MES/NaOH (pH 6.0). Under these conditions, migration times of 12.2 s for creatinine and 8.6 s for uric acid were achieved. The LOD value is 2.4 mg/L for creatinine and 0.9 mg/L for uric acid; the RSD for the migration time varies in the range 0.7-1.1% (intra day) to 1.0-7.5% (inter day); RSDs for the peak areas equalled 3.4-4.0% (intra day) and 4.3-4.7% (inter day). The determined creatinine values in seven urine samples vary in the range 221-1394 mg/L for creatinine and 87-615 mg/L for uric acid. t-Test did not reveal any statistically significant difference between the developed CE methodologies and reference methods - Jaffé reaction for creatinine and enzymatic uricase test for uric acid. PMID:24114779

Pavlí?ek, Václav; T?ma, Petr; Mat?j?ková, Jana; Samcová, Eva

2014-04-01

11

Uric acid and urea in relation to protein catabolism in long-term fasting geese  

Microsoft Academic Search

Five ganders were subjected to an experimental fast comparable to that which spontaneously occurs during breeding in domestic geese, and during migration and breeding in various wild birds. Plasma uric acid and urea concentrations, and their excretion as a proportion of total nitrogen excretion, were studied in relation to daily change in body mass per unit body mass, dm\\/mdt. This

Jean-Patrice Robin; Yves Cherel; Henri Girard; Alain Géloen; Yvon Maho

1987-01-01

12

Bioelectronic tongue for the simultaneous determination of urea, creatinine and alkaline ions in clinical samples.  

PubMed

Urea and creatinine biosensors based on urease and creatinine deiminase, respectively, covalently immobilized onto ammonium selective electrodes, were included in an array together with sensors sensitive to ammonium, potassium and sodium. Generic sensors to alkaline ions were also included. All the sensors used were of all-solid-state type, employing polymeric membranes and having rather nonspecific response characteristics. A response model based on artificial neural networks was built and tested for the simultaneous determination of urea, creatinine, ammonium, potassium and sodium. The results show that it is possible to obtain a good multivariate calibration model. In this way, the developed bioelectronic tongue was successfully applied to multidetermination of the five species in raw and spiked urine samples. Predicted concentrations showed a good agreement with reference methods of analysis, allowing a simple direct method for determining urea and creatinine in real samples. At the same time, this method permitted to obtain the concentrations of the alkaline interferences (endogenous ammonium, potassium and sodium) without the need of eliminating them. PMID:17931852

Gutiérrez, Manuel; Alegret, Salvador; del Valle, Manel

2008-01-18

13

Changes in Serum Electrolytes, Urea, and Creatinine in Aloe Vera-treated Rats  

PubMed Central

This study was carried out to investigate the effect of Aloe vera extract (AvE) on serum electrolytes, urea, and creatinine as indices of renal function in Sprague-Dawley rats. Twelve male Sprague-Dawley rats weighing between 80 and 130 g were used. Rats were divided into two groups: The control and the test groups (n=6). The test group received 1 ml of AvE daily for 28 days. Both the groups fed on standard rat chow and water ad libitum. The results showed a decrease in serum levels of sodium, and potassium, but an increase in the serum levels of bicarbonate, urea, and creatinine in the test group. The changes seen were, however, statistically insignificant, except for the serum levels of sodium and creatinine (P<0.05). It is thus concluded that AvE impairs renal handling of electrolytes with consequent hyponatremia and hypercreatinemia. However, this might be of therapeutic value in conditions associated with hypernatremia.

Saka, WA; Akhigbe, RE; Popoola, OT; Oyekunle, OS

2012-01-01

14

Comparison of serum creatinine, uric acid, albumin and glucose in male professional endurance athletes compared with healthy controls.  

PubMed

Owing to considerable physical, endocrinological and metabolic adaptations, the analysis of biochemical data in elite and top-class athletes requires caution. With the aim to identify metabolic and biochemical adaptations to particular lifestyle conditions, such as regular and strenuous physical exercise, we measured the concentration of serum albumin, creatinine, uric acid and glucose in 80 male professional cyclists, 37 male members of the Italian national cross-country ski team and 60 male healthy sedentary controls at rest. At variance with earlier investigations, endurance athletes showed significantly decreased concentrations of serum creatinine (controls: 83.1+/-11.0 micromol/l; skiers: 78.0+/-8.4 micromol/l; p<0.05; cyclists: 73.8+/-10.4 micromol/l; p<0.01), uric acid (controls: 362+/-69 micromol/l; skiers: 331 +/-70 micromol/l; p<0.05; cyclists: 312+/-61 micromol/l; p<0.01) and glucose (controls: 5.35+/-0.54 mmol/l; skiers: 4.94+/-0.41 mmol/l; p<0.01; cyclists: 4.94+/-0.42 mmol/l; p<0.01). The concentration of serum albumin was also decreased in athletes, but the difference did not reach statistical significance (controls: 4.76+/-0.26 g/l; skiers: 4.71+/-0.22 g/l; p=0.384; cyclists: 4.68+/-0.22 g/l; p=0.393). Results of the present investigation demonstrate that values of laboratory testing lying outside conventional reference limits calculated on sedentary populations might express physiological adaptations to regular and demanding physical aerobic activity, emphasizing the need for the estimation of reliable reference limits in elite and professional athletes, to avoid equivocal interpretation of results within clinical and anti-doping contests. PMID:15259381

Lippi, Giuseppe; Brocco, Giorgio; Franchini, Massimo; Schena, Federico; Guidi, Giancesare

2004-01-01

15

[Pitfalls in the interpretation of laboratory parameters-electrolytes, urea, creatinine].  

PubMed

When it comes to interpret parameters of electrolyte balance and kidney function, it is important to keep pathophysiology and the theory on reference intervals in mind. Hyponatremia is most often caused by excess water. A low sodium concentration in urine should prompt a clinical evaluation of volume status. In case of suspected acute kidney failure, fractionated sodium excretion and fractionated urea excretion are able to provide insights on prerenal or renal origin of the disorder. Disruption in potassium homoeostasis can occur due to changes in supply or renal elimination as well as due to changes in the potassium balance between the extra- and intracellular compartments. The transtubular potassium gradient can help in the differential diagnosis of hyperkalemia. Evaluation of kidney function should begin with determination of serum creatinine, accompanied by an estimate of the glomerular filtration rate, as calculated by the CKD-EPI equation. As a consequence of non-renal determinants of serum creatinine, this equation has been shown to overestimate true GFR in elderly and hospitalized patients. This can result in overdosing of renally-cleared drugs. Clearance determinations can be of use in this context. PMID:23876752

Risch, Lorenz; Hess, Bernhard

2013-08-01

16

Analytical nanosphere sensors using quantum dot-enzyme conjugates for urea and creatinine.  

PubMed

An enzyme-linked analytical nanosphere sensor (ANSor) is described, responding to enzyme-substrate turnover in the vicinity of a quantum dot (QD) due to coimmobilized enzyme and pH sensitive ligand. QD capping by mercapto-alkanoic acids were rejected as a pH sensitive ligand, but with the use of a layer-by-layer assembly on mercaptopropionic capped QDs and an intermediate poly(allylamine hydrochloride) layer, anthraquinone sulfonate (calcium red, CaR) was introduced to modify the pKa in the immobilized system > 8. QD-CaR absorption shows spectral overlap with QD530 emission at all pHs and gives a complex pH dependent fluorescence resonance energy transfer (FRET) efficiency, due to excited state proton transfer (?(ex) = 540 nm; ?(em) = 585 nm). In contrast QD615-CaR with spectral overlap between the QD and CaR gave a strong and reproducible pH response. QD-urease and QD-creatinine deiminase conjugates could be linked with pH changes produced by enzyme degradation of urea and creatinine, respectively. Close coupling between the pH sensitive QD and enzyme conjugate maximized signal compared with solution based assays: QD-urease and QD-CD bioconjugates were tested in model biological media (Dulbecco's modified Eagle's Medium and fetal calf serum) and in urine, showing a response in 3-4 min. PMID:20939534

Ruedas-Rama, Maria J; Hall, Elizabeth A H

2010-11-01

17

Preparation and certification of creatinine and urea reference materials with certified purity as a traceability source in clinical chemical measurements  

Microsoft Academic Search

Purity certified reference materials (CRMs) are playing a key role in metrological traceability, because they form the basis\\u000a for many traceability chains in chemistry. Recently, the National Metrology Institute of Japan (NMIJ) has developed two purity\\u000a CRMs for creatinine (NMIJ CRM 6005-a) and urea (NMIJ CRM 6006-a), because the concentrations of these two compounds are frequently\\u000a measured in clinical laboratories

Akiko Takatsu; Sakae Eyama; Mika Saeki

2008-01-01

18

Uric acid, urea, and ammonia concentrations in serum and uric acid concentration in excreta as indicators of amino acid utilization in diets for broilers.  

PubMed

Five experiments were conducted to determine if serum uric acid, serum urea N (SUN), serum ammonia, and the uric acid content of the excreta (UAE) could be used to determine the efficacy of amino acid (AA) utilization in diets for broilers. All experiments were conducted with Ross x Ross 308 or 708 broilers from 0 to 14 or 0 to 18 d posthatching in brooder batteries. Treatments had 6 or 7 replications with at least 6 broilers per replicate pen. All diets were corn and soybean meal-based and formulated to contain 1.0% Ca and 0.45% nonphytate P and to meet or exceed the requirements of all nutrient requirements except total Lys, Met, and Thr (experiment 1) or Met (experiments 2 to 5). Experiment 1 consisted of 2 dietary treatments. Diet 1 was formulated to be deficient in Lys, Thr, and Met and diet 2 was formulated to be adequate in all nutrients. Broilers fed the AA-adequate diet had increased (P<0.01 to 0.03) ADG, ADFI, and G:F compared with broilers fed the AA-deficient diet. Serum uric acid, SUN, serum ammonia, and UAE were not affected (P=0.34 to 0.70) by dietary treatment. In experiments 2 to 5, diets contained 1.35% total Lys, 2 levels of Met (0.50 or 0.76 TSAA:Lys), and without or with Gly supplementation up to 2.32% Gly+Ser. Broilers fed diets containing supplemental Met in experiments 2 to 5 had increased (P=0.01 to 0.03) ADG, ADFI, and G:F. Gain:feed was increased (P=0.01 to 0.07) in broilers fed supplemental Gly. Serum uric acid and SUN were decreased (P<0.01) after a 2-h fast in broilers fed supplemental Met and Gly. Serum uric acid and SUN also were decreased at other times after fasting, but the 2-h fast gave the most consistent response. Uric acid content of the excreta was decreased (P<0.01) in broilers fed supplemental Met. Serum ammonia was decreased (P<0.01 to 0.02) in experiments 2, 3, and 4 at varying times postfeeding but was not affected by diet in experiment 5. The results of this research indicate that serum uric acid, SUN, and UAE concentrations can be used as an indicator of AA utilization in broilers fed AA-adequate and AA-deficient diets. PMID:20075281

Donsbough, A L; Powell, S; Waguespack, A; Bidner, T D; Southern, L L

2010-02-01

19

Kinetics and fates of ammonia, urea, and uric acid during oocyte maturation and ontogeny of the Atlantic halibut ( Hippoglossus hippoglossus L.)  

Microsoft Academic Search

Considering that amino acids constitute an important energy fuel during early life of the Atlantic halibut (Hippoglossus hippoglossus L.), it is of interest to understand how the nitrogenous end products are handled. In this study we focused on the kinetics and fates of ammonia, urea and uric acid. The results showed that ammonia (TAmm: NH3+NH4+), and urea–N contents increased during

B. F. Terjesen; R. N. Finn; B. Norberg; I. Rønnestad

2002-01-01

20

Kinetics and fates of ammonia, urea, and uric acid during oocyte maturation and ontogeny of the Atlantic halibut (Hippoglossus hippoglossus L.).  

PubMed

Considering that amino acids constitute an important energy fuel during early life of the Atlantic halibut (Hippoglossus hippoglossus L.), it is of interest to understand how the nitrogenous end products are handled. In this study we focused on the kinetics and fates of ammonia, urea and uric acid. The results showed that ammonia (T(Amm): NH(3)+NH(4)(+)), and urea-N contents increased during final oocyte maturation. Urea-N excretion dominated the total nitrogenous end product formation in early embryos. Later, yolk T(Amm) levels increased in embryos and ammonia excretion was low. In the last part of the embryonic stage T(Amm) accumulation dominated, and was apparently due to yolk storage. Around hatching, the larval body tissues (larva with yolk-sac removed) accounted for 68% of whole animal urea-N accumulation, while T(Amm) levels increased predominately by yolk accumulation. Afterwards, ammonia excretion dominated and uric acid accumulation accounted for less than 1%. Urea, synthesised either through the ornithine-urea cycle, argininolysis or uricolysis, accounted for approximately 8% of total nitrogenous end product formation in yolk-sac larvae. The results suggested that a sequence occurred regarding which nitrogenous end products dominated and how they were handled. Urea excretion dominated in early embryos (<7 dPF), followed by yolk ammonia accumulation (7-12 dPF), and finally, ammonia excretion dominated in later embryonic and yolk-sac larval stages (>12 dPF). PMID:11818232

Terjesen, B F; Finn, R N; Norberg, B; Rønnestad, I

2002-02-01

21

Blood Urea Nitrogen/Creatinine Ratio Identifies a High-Risk but Potentially Reversible Form of Renal Dysfunction in Patients With Decompensated Heart Failure  

PubMed Central

Background Identifying reversible renal dysfunction (RD) in the setting of heart failure is challenging. The goal of this study was to evaluate whether elevated admission blood urea nitrogen/creatinine ratio (BUN/Cr) could identify decompensated heart failure patients likely to experience improvement in renal function (IRF) with treatment. Methods and Results Consecutive hospitalizations with a discharge diagnosis of heart failure were reviewed. IRF was defined as ?20% increase and worsening renal function as ?20% decrease in estimated glomerular filtration rate. IRF occurred in 31% of the 896 patients meeting eligibility criteria. Higher admission BUN/Cr was associated with inhospital IRF (odds ratio, 1.5 per 10 increase; 95% confidence interval [CI], 1.3–1.8; P<0.001), an association persisting after adjustment for baseline characteristics (odds ratio, 1.4; 95% CI, 1.1–1.8; P=0.004). However, higher admission BUN/Cr was also associated with post-discharge worsening renal function (odds ratio, 1.4; 95% CI, 1.1–1.8; P=0.011). Notably, in patients with an elevated admission BUN/Cr, the risk of death associated with RD (estimated glomerular filtration rate <45) was substantial (hazard ratio, 2.2; 95% CI, 1.6–3.1; P<0.001). However, in patients with a normal admission BUN/Cr, RD was not associated with increased mortality (hazard ratio, 1.2; 95% CI, 0.67–2.0; P=0.59; p interaction=0.03). Conclusions An elevated admission BUN/Cr identifies decompensated patients with heart failure likely to experience IRF with treatment, providing proof of concept that reversible RD may be a discernible entity. However, this improvement seems to be largely transient, and RD, in the setting of an elevated BUN/Cr, remains strongly associated with death. Further research is warranted to develop strategies for the optimal detection and treatment of these high-risk patients.

Brisco, Meredith A.; Coca, Steven G.; Chen, Jennifer; Owens, Anjali Tiku; McCauley, Brian D.; Kimmel, Stephen E.; Testani, Jeffrey M.

2014-01-01

22

Evaluation of urea reduction ratio estimated from the integrated value of urea concentrations in spent dialysate.  

PubMed

We propose a new apparatus and method to estimate accurate urea reduction ratio without influence of any rebound. For this purpose, we have developed an improved version of a chemiluminescence-based urea sensor capable of measuring urea concentration in spent dialysate (CD ) at 2-min intervals. The correlation coefficient between the readouts of the sensor and the conventional enzyme-UV method was 0.97 and the sensor was not affected by 9?mmol/L uric acid, creatinine, or ammonia. Using the urea sensor, CD was measured as a function of dialysis time t during dialysis sessions for various blood flow rates. The urea reduction ratio based on the mass of the urea reduced (m URR) was estimated from the integrated value of CD (t). When in vitro urea concentrations are measured during a dialysis session in model blood (urea solution) at a constant volume (V) in a vessel, the plots of m URR were congruous with theoretical curves of conventional URR calculated based on the one-pool model, and thus the accuracy of m URR was confirmed. On the other hand, in in vivo measurements of CD (t) during dialysis treatment for two patients, the plots of the m URR were not congruous with the theoretical curves of URR. Such a difference between URR and m URR was explained by the deviation of actual dialysis from the one-pool model, and it was concluded that m URR might be accurate under any dialysis condition. PMID:24720411

Ozaki, Masahiro; Hori, Jun'ya; Okabayashi, Tohru

2014-04-01

23

Correlating the amount of urea, creatinine, and glucose in urine from patients with diabetes mellitus and hypertension with the risk of developing renal lesions by means of Raman spectroscopy and principal component analysis.  

PubMed

Patients with diabetes mellitus and hypertension (HT) diseases are predisposed to kidney diseases. The objective of this study was to identify potential biomarkers in the urine of diabetic and hypertensive patients through Raman spectroscopy in order to predict the evolution to complications and kidney failure. Urine samples were collected from control subjects (CTR) and patients with diabetes and HT with no complications (lower risk, LR), high degree of complications (higher risk, HR), and doing blood dialysis (DI). Urine samples were stored frozen (-20°C) before spectral analysis. Raman spectra were obtained using a dispersive spectrometer (830-nm, 300-mW power, and 20-s accumulation). Spectra were then submitted to principal component analysis (PCA) followed by discriminant analysis. The first PCA loading vectors revealed spectral features of urea, creatinine, and glucose. It has been found that the amounts of urea and creatinine decreased as disease evoluted from CTR to LR/HR and DI (PC1, p<0.05), and the amount of glucose increased in the urine of LR/HR compared to CTR (PC3, p<0.05). The discriminating model showed better overall classification rate of 70%. These results could lead to diagnostic information of possible complications and a better disease prognosis. PMID:23929457

Bispo, Jeyse Aliana Martins; de Sousa Vieira, Elzo Everton; Silveira, Landulfo; Fernandes, Adriana Barrinha

2013-08-01

24

Atorvastatin Combining with Probucol: A New Way to Reduce Serum Uric Acid Level during Perioperative Period of Interventional Procedure  

PubMed Central

Uric acid has ever been considered as one of contrast induced acute kidney injury's risk factors. Atorvastatin and probucol can both improve contrast induced acute kidney injury separately. This prospective study is to assess their effect on reducing serum uric acid level and contrast induced acute kidney injury during perioperative period of interventional procedure. On the basis of different doses of atorvastatin and probucol, 208 cases admitted for coronary angiography or percutaneous coronary intervention were randomly classified into standard combined group (S-C group), intensive combined group (I-C group), and intensive atorvastatin group (I-A group). Patients' blood urea nitrogen, serum creatinine, and serum uric acid were measured and estimated glomerular filtration rate was evaluated 24 hours before and after the procedure. After procedure, blood urea nitrogen in all the three groups decreased; Scr of S-C group and I-A group increased significantly, while estimated glomerular filtration decreased in the S-C group (P < 0.05); serum uric acid in S-C group and I-C group decreased significantly (P < 0.05). Combination treatment of atorvastatin and probucol before intervention could reduce perioperative serum uric acid level; meanwhile, the intensive combined treatment can improve the contrast induced acute kidney injury. The result was the same for hypertensive patients.

Li, Hong; Li, Ximing; Ma, Hongjun; Wang, Yiran; Fu, Naikuan; Jin, Dongxia; Cong, Hongliang

2014-01-01

25

Creatinine clearance test  

MedlinePLUS

... the kidneys are working. The test compares the creatinine level in urine with the creatinine level in blood . Creatinine is ... creatinine level increases in the blood because less creatinine is released through the urine.

26

Elevated Uric Acid Increases the Risk for Acute Kidney Injury  

Microsoft Academic Search

BackgroundUric acid has been proposed to play a role in acute kidney injury. We therefore investigated the potential influence of preoperative serum uric acid (SUA) on acute kidney injury in patients undergoing cardiovascular (CV) surgery. The primary aims were to investigate the incidence of acute kidney injury, peak serum creatinine (SCr) concentrations, hospital length of stay and days on mechanical

Vijay Lapsia; Richard J. Johnson; Bhagwan Dass; Michiko Shimada; Ganesh Kambhampati; Noel I. Ejaz; Amir A. Arif; A. Ahsan Ejaz

27

Uric acid test (image)  

MedlinePLUS

Uric acid urine test is performed to check for the amount of uric acid in urine. Urine is collected over a 24 ... for testing. The most common reason for measuring uric acid levels is in the diagnosis or treatment of ...

28

Prediction of Creatinine Clearance from Serum Creatinine  

Microsoft Academic Search

A formula has been developed to predict creatinine clearance (Ccr) from serum creatinine (Scr) in adult males: Ccr = (140 – age) (wt kg)\\/72 × Scr(mg\\/100ml) (15% less in females). Derivation included the relationship found between age and 24-hour creatinine excretion\\/kg in 249 patients aged 18–92. Values for Ccr were predicted by this formula and four other methods and the

Donald W. Cockcroft; Henry Gault

1976-01-01

29

Serumurinezuur Spiegels bij Ouderen; Correlaten en Gevolgen van Verhoogd Serumurinezuur (Serum Uric Acid Levels in the Elderly; Correlates and Consequences of Increased Serum Uric Acid).  

National Technical Information Service (NTIS)

In 460 apparently healthy Dutch elderly, ages 65-79, serum uric acid correlates were separately studied for men and women by way of linear regression analyses. Diuretic therapy, total serum cholesterol (women only) and creatinine clearance were correlated...

H. Eshuis H. Loenen

1989-01-01

30

Uric acid protection of nucleobases from ozone-induced degradation  

SciTech Connect

Uric acid has been proposed to be an important antioxidant and free radical scavenger in humans. Of the purine and pyrimidine compounds examined in this study, uric acid showed the greatest susceptibility to ozone-induced degradation. The parent compounds, purine and pyrimidine, were more resistant to ozonation than were the nucleobases. When the degradation of OH-substituted purines was examined, it was found that the more OH groups on the purine ring, the more readily the purine was degraded. Urea and allantoin were identified as degradation products of uric acid. The relative rates of nucleobase degradation in the presence and absence of uric acid were compared. Uric acid protected thymine, guanine, and uracil from degradation by ozone. In this system uric acid was found to protect the nucleobases as effectively as reduced glutathione.

Meadows, J.; Smith, R.C.

1986-05-01

31

Low Protein Diet Inhibits Uric Acid Synthesis and Attenuates Renal Damage in Streptozotocin-Induced Diabetic Rats  

PubMed Central

Aim. Several studies indicated that hyperuricemia may link to the worsening of diabetic nephropathy (DN). Meanwhile, low protein diet (LPD) retards exacerbation of renal damage in chronic kidney disease. We then assessed whether LPD influences uric acid metabolism and benefits the progression of DN in streptozotocin- (STZ-) induced diabetic rats. Methods. STZ-induced and control rats were both fed with LPD (5%) and normal protein diet (18%), respectively, for 12 weeks. Vital signs, blood and urinary samples for UA metabolism were taken and analyzed every 3 weeks. Kidneys were removed at the end of the experiment. Results. Diabetic rats developed into constantly high levels of serum UA (SUA), creatinine (SCr) and 24?h amounts of urinary albumin excretion (UAE), creatintine (UCr), urea nitrogen (UUN), and uric acid (UUA). LPD significantly decreased SUA, UAE, and blood glucose, yet left SCr, UCr, and UUN unchanged. A stepwise regression showed that high UUA is an independent risk factor for DN. LPD remarkably ameliorated degrees of enlarged glomeruli, proliferated mesangial cells, and hyaline-degenerated tubular epithelial cells in diabetic rats. Expression of TNF-? in tubulointerstitium significantly decreased in LPD-fed diabetic rats. Conclusion. LPD inhibits endogenous uric acid synthesis and might accordingly attenuate renal damage in STZ-induced diabetic rats.

Ma, Jing; Liu, Yan; Tan, Rongshao; Liu, Houqiang; Lao, Gancheng

2014-01-01

32

Uric acid - blood  

MedlinePLUS

Uric acid is a chemical created when the body breaks down substances called purines. Purines are found in ... mackerel, dried beans and peas, and beer. Most uric acid dissolves in blood and travels to the kidneys. ...

33

Crystallization of uric acid  

NASA Astrophysics Data System (ADS)

Crystals of uric acid have been grown in tetra methoxy silane and silica gel medium. Small winged, transparent, platy crystals of uric acid of about 0.5x0.5x0.1 mm were grown and were found to be hydrated uric acid.

Kalkura, S. Narayana; Vaidyan, V. K.; Kanakavel, M.; Ramasamy, P.

1993-09-01

34

Dietary, anthropometric, and biochemical determinants of uric acid in free-living adults  

PubMed Central

Background High plasma uric acid (UA) is a prerequisite for gout and is also associated with the metabolic syndrome and its components and consequently risk factors for cardiovascular diseases. Hence, the management of UA serum concentrations would be essential for the treatment and/or prevention of human diseases and, to that end, it is necessary to know what the main factors that control the uricemia increase. The aim of this study was to evaluate the main factors associated with higher uricemia values analyzing diet, body composition and biochemical markers. Methods 415 both gender individuals aged 21 to 82 years who participated in a lifestyle modification project were studied. Anthropometric evaluation consisted of weight and height measurements with later BMI estimation. Waist circumference was also measured. The muscle mass (Muscle Mass Index – MMI) and fat percentage were measured by bioimpedance. Dietary intake was estimated by 24-hour recalls with later quantification of the servings on the Brazilian food pyramid and the Healthy Eating Index. Uric acid, glucose, triglycerides (TG), total cholesterol, urea, creatinine, gamma-GT, albumin and calcium and HDL-c were quantified in serum by the dry-chemistry method. LDL-c was estimated by the Friedewald equation and ultrasensitive C-reactive protein (CRP) by the immunochemiluminiscence method. Statistical analysis was performed by the SAS software package, version 9.1. Linear regression (odds ratio) was performed with a 95% confidence interval (CI) in order to observe the odds ratio for presenting UA above the last quartile (?UA?>?6.5 mg/dL and ? UA?>?5 mg/dL). The level of significance adopted was lower than 5%. Results Individuals with BMI???25 kg/m2 OR?=?2.28(1.13-4.6) and lower MMI OR?=?13.4 (5.21-34.56) showed greater chances of high UA levels even after all adjustments (gender, age, CRP, gamma-gt, LDL, creatinine, urea, albumin, HDL-c, TG, arterial hypertension and glucose). As regards biochemical markers, higher triglycerides OR?=?2.76 (1.55-4.90), US-CRP OR?=?2.77 (1.07-7.21) and urea OR?=?2.53 (1.19-5.41) were associated with greater chances of high UA (adjusted for gender, age, BMI, waist circumference, MMI, glomerular filtration rate, and MS). No association was found between diet and UA. Conclusions The main factors associated with UA increase were altered BMI (overweight and obesity), muscle hypotrophy (MMI), higher levels of urea, triglycerides, and CRP. No dietary components were found among uricemia predictors.

2013-01-01

35

Creatinine blood test  

MedlinePLUS

Creatinine is a chemical waste product of creatine. Creatine is a chemical made by the body and is used to supply energy mainly to muscles. This test is done to see how well your kidneys work. Creatinine is removed from the body ...

36

The interactive effects of glycine, total sulfur amino acids, and lysine supplementation to corn-soybean meal diets on growth performance and serum uric acid and urea concentrations in broilers.  

PubMed

Four experiments were conducted to determine the interactive effects of Gly, TSAA, and Lys in corn-soybean meal diets on growth performance of broilers. All experiments were conducted with female Ross x Ross 308 or 708 broilers in brooder batteries from 0 to 18 d posthatching. Treatments had 5 to 8 replications with 5 or 6 broilers per replicate pen. Diets in all experiments were fed without or with Gly (2.32% total Gly + Ser). All diets contained 0.25% l-Lys.HCl except in experiment 1, where no crystalline Lys was added. In experiment 1, the total dietary Lys level was 1.26% with TSAA:Lys of 0.72 and 0.76. Increasing TSAA:Lys increased (P < 0.07) G:F. The main effect of Gly was not significant for ADG, ADFI, or G:F; however, G:F was increased by Gly in broilers fed 0.72 but not in those fed 0.76 TSAA:Lys (Gly x TSAA:Lys, P < 0.03). In experiment 2, the total dietary Lys level was 1.26% with TSAA:Lys of 0.51, 0.68, 0.72, and 0.76. Glycine addition did not affect ADG, ADFI, or G:F; however, increasing TSAA:Lys linearly increased (P < 0.01) ADG, ADFI, and G:F and the response was quadratic for ADG and G:F. Experiment 3 was similar to experiment 2 except the total dietary Lys level was 1.35%. Glycine addition increased (P < 0.03) G:F and decreased (P < 0.04) serum uric acid (SUA) and serum urea N concentrations. Also, increasing TSAA:Lys linearly and quadratically (P < 0.02) increased ADG, ADFI, and G:F. In experiment 4, broilers were fed 2 levels of total dietary Lys (1.26 and 1.35%), 3 levels of TSAA:Lys (0.72, 0.76, and 0.80), and without or with Gly supplementation up to a total of 2.32% Gly + Ser. Glycine addition increased ADG (P < 0.02) and G:F (P < 0.01). The increase in G:F with Gly was not the same for all TSAA:Lys (Gly x TSAA:Lys, P < 0.07). Increasing Lys increased (P < 0.01 to 0.10) ADG, ADFI, and G:F. Glycine addition increased ADG and ADFI more in broilers fed 1.35% Lys than in those fed 1.26% Lys (Lys x Gly, P < 0.09). Glycine addition increased SUA in broilers fed 1.26% Lys but decreased SUA in broilers fed 1.35% Lys (P < 0.01). Glycine addition decreased SUA in broilers fed the TSAA:Lys of 0.80 but not at the other TSAA:Lys (P < 0.08). These data indicate that Gly increased G:F and decreased SUA in diets with 1.35% Lys and excess TSAA. PMID:19531711

Powell, S; Bidner, T D; Southern, L L

2009-07-01

37

Certification of the Contents of Calcium, Ammoniacal-Nitrogen, Nitrate-Nitrogen and Total Nitrogen in a Sample of Calcium Ammonium Nitrate Fertiliser and Uric-Nitrogen, Biuret and Total Nitrogen in a Sample of Urea Fertiliser.  

National Technical Information Service (NTIS)

The report describes the preparation of two reference materials for the analysis of nitrogen-containing fertilizers: a commercial product of calcium ammonium nitrate (CRM 178); a commercial product of urea (CRM 179). The calcium ammonium nitrate (CRM 178)...

B. Griepink G. Serrini G. Ingram

1985-01-01

38

Identification of Uric Acid and Ascorbic Acid by Chromatography  

Microsoft Academic Search

P. L. Kirk and E. L. Duggan1 have described the identification of various substances of clinical and biological importance, and we have published a quantitative micromethod for determination of urea2. In this communication we report on a colour reaction for uric acid and ascorbic acid in paper chromatography. It may be noted that F. Weygand3 and Z. Prochazka and S.

F. Bode; H. J. Hübener

1952-01-01

39

Urine alkalization facilitates uric acid excretion  

PubMed Central

Background Increase in the incidence of hyperuricemia associated with gout as well as hypertension, renal diseases and cardiovascular diseases has been a public health concern. We examined the possibility of facilitated excretion of uric acid by change in urine pH by managing food materials. Methods Within the framework of the Japanese government's health promotion program, we made recipes which consist of protein-rich and less vegetable-fruit food materials for H+-load (acid diet) and others composed of less protein but vegetable-fruit rich food materials (alkali diet). Healthy female students were enrolled in this consecutive 5-day study for each test. From whole-day collected urine, total volume, pH, organic acid, creatinine, uric acid and all cations (Na+,K+,Ca2+,Mg2+,NH4+) and anions (Cl-,SO42-,PO4-) necessary for the estimation of acid-base balance were measured. Results Urine pH reached a steady state 3 days after switching from ordinary daily diets to specified regimens. The amount of acid generated ([SO42-] +organic acid-gut alkai) were linearly related with those of the excretion of acid (titratable acidity+ [NH4+] - [HCO3-]), indicating that H+ in urine is generated by the metabolic degradation of food materials. Uric acid and excreted urine pH retained a linear relationship, where uric acid excretion increased from 302 mg/day at pH 5.9 to 413 mg/day at pH 6.5, despite the fact that the alkali diet contained a smaller purine load than the acid diet. Conclusion We conclude that alkalization of urine by eating nutritionally well-designed food is effective for removing uric acid from the body.

2010-01-01

40

Urea Kinetics and When to Commence Dialysis  

Microsoft Academic Search

Blood urea and serum creatinine levels are important factors in deciding when to start dialysis. Recently, in the assessment of dialysis adequacy, emphasis has shifted from reliance on these parameters to use of kinetic methods. We therefore applied urea kinetic modelling (UKM) to 63 consecutive chronic renal failure (CRF) patients at the time dialysis commenced and compared the results to

James Tattersall; Roger Greenwood; Ken Farrington

1995-01-01

41

Effects of cilnidipine on serum uric acid level and urinary nitrogen monoxide excretion in patients with hypertension.  

PubMed

The effects of cilnidipine on the serum uric acid level and urinary NO excretion in hypertensive patients were investigated. Blood and urine samples of 16 hypertensive outpatients were collected before and 2 months after cilnidipine therapy (10 mg). The serum uric acid level decreased significantly after cilnidipine treatment, while the uric acid-creatinine clearance ratio was unaffected. The cilnidipine medication produced a significant increase in urinary NO excretion, although amlodipine did not change it significantly. Therefore, cilnidipine has a profound antihypertensive effect and may reduce the serum uric acid level and increase NO production in the kidney. PMID:22681507

Hamada, Toshihiro; Yamada, Kensaku; Mizuta, Einosuke; Watanabe, Arisa; Osaki, Tomohiro; Ishida, Katsunori; Hasegawa, Akira; Sakata, Shinji; Mishima, Mutsuo; Ogino, Kazuhide; Nosaka, Yoshihito; Miyazaki, Satoshi; Ohtahara, Akira; Ninomiya, Haruaki; Kato, Masahiko; Yoshida, Akio; Taniguchi, Shin-ichi; Yamamoto, Kazuhiro; Hisatome, Ichiro

2012-01-01

42

Association of serum uric acid with proteinuria in type 2 diabetic patients  

PubMed Central

Background: Various findings suggest that uric acid is an inflammatory factor and may have a role in endothelial dysfunction and act as a mediator of diabetic nephropathy. The objective of this study was to evaluate the relationships between serum uric acid level and level of proteinuria in type 2 diabetic (T2D) patients. Materials and Methods: A cross-sectional analytical study was conducted in 60 patients with T2D without a history of gout. None was treated with allopurinol. Venous blood samples were obtained in fasting state for determinations of serum creatinine, uric acid, and hemoglobin A1c (HbA1c) (reference range 3.8-5.5%); 24-h urine proteinuria was also measured. Results: Mean age of the patients was 57 ± 8.3 years. Mean ± standard error (SE) of serum creatinine was 0.98 ± 0.028 mg/dL, mean ± SE of serum uric acid was 4.5 ± 0.15 mg/dL, and mean ± SE of proteinuria was 388 ± 28.7 mg/day (median = 303.5 mg/day). There was no significant difference in serum uric acid, HbA1c, and creatinine level between males and females (P > 0.05). There was a significant positive association between body mass index (BMI) and serum uric acid levels (r = 0.428, P = 0.001). After adjustment for weight, a significant positive association of serum uric acid with level of proteinuria was seen (r = 0.47, P < 0.001). Conclusion: Serum uric acid had a significant positive association with diabetic nephropathy. It might be hypothesized that serum uric acid plays a role in diabetic nephropathy in T2D.

Behradmanesh, Saeed; Horestani, Mohammad Karami; Baradaran, Azar; Nasri, Hamid

2013-01-01

43

Effect of urine pH changed by dietary intervention on uric acid clearance mechanism of pH-dependent excretion of urinary uric acid  

PubMed Central

Background The finding reported in a previous paper - alkalization of urine facilitates uric acid excretion - is contradictory to what one might expect to occur: because food materials for the alkalization of urine contain fewer purine bodies than those for acidification, less uric acid in alkaline urine should have been excreted than in acid urine. To make clear what component of uric acid excretion mechanisms is responsible for this unexpected finding, we simultaneously collected data for the concentration of both creatinine and uric acid in serum as well as in urine, in order to calculate both uric acid and creatinine clearances. Methods Within the framework of the Japanese government’s health promotion program, we made recipes which consisted of protein-rich and less vegetable-fruit food materials for H?+?-load (acidic diet) and others composed of less protein and more vegetable-fruit rich food materials (alkaline diet). This is a crossover study within some limitations. Healthy female students, who had no medical problems at the regular physical examination provided by the university, were enrolled in this consecutive 5-day study for each test. From whole-day collected urine, total volume, pH, organic acid, creatinine, uric acid, titratable acid and all cations (Na+,K+,Ca2+,Mg2+,NH4+) and anions (Cl?,SO42?,PO4?) necessary for the estimation of acid–base balance were measured. In the early morning before breakfast of the 1st, 3rd and 5th experimental day, we sampled 5?mL of blood to estimate the creatinine and uric acid concentration in serum. Results and discussion Urine pH reached a steady state 3?days after switching from ordinary daily diets to specified regimens. The amount of acid generated ([SO42?]?+?organic acid???gut alkali)was linearly related with the excretion of acid (titratable acid?+?[NH4+]???[HCO3?]), indicating that H?+?in urine is generated by the metabolic degradation of food materials. Uric acid and excreted urine pH retained a linear relationship, as reported previously. Among the five factors which are associated with calculating clearances for both uric acid and creatinine, we identified a conspicuous difference between acidic and alkaline diets in the uric acid concentration in serum as well as in urine; uric acid in the serum was higher in the acidic group than in the alkaline group, while uric acid in the urine in the acidic group was lower than that in the alkaline group. These changes of uric acid in acidic urine and in serum were reflected in the reduction of its clearance. From these observations, it is considered that uric acid may be reabsorbed more actively in acidic urine than in alkaline urine. Conclusion We conclude that alkalization of urine by eating nutritionally well-designed alkaline -prone food is effective for removing uric acid from the body.

2012-01-01

44

Uric acid and the kidney.  

PubMed

Uric acid, the end product of purine metabolism, is excreted predominantly by the proximal tubules. Abnormal serum levels of uric acid are due to alterations in production or excretion. Fractional excretion of uric acid is helpful in determining the underlying etiology of hypouricemia or hyperuricemia in children. Abnormalities in the molecular mechanisms that control renal uric acid tubular transport are implicated in various disorders associated with abnormal uric acid levels. Gout is rare in children; yet its presence necessitates evaluation for enzymatic defects in purine metabolism. Well-known effects of uric acid on the kidney include nephrolithiasis and acute kidney injury (AKI) in the setting of tumor lysis. However, recent data suggest that uric acid may be an important factor in the pathogenesis of AKI in general, as well as of chronic kidney disease (CKD) and hypertension. Hence, uric acid may not only be a marker but also a potential therapeutic target in kidney disease. Nonetheless, because of confounders, more studies are needed to clarify the association between uric acid and multifactorial disorders of the kidney. PMID:23824181

Fathallah-Shaykh, Sahar A; Cramer, Monica T

2014-06-01

45

CREATININE CLEARANCE IN CLINICAL MEDICINE  

PubMed Central

Clearance of endogenous creatinine offers a reliable clinical means of determining quantitative renal damage. The rate of clearance (Ccr) is obtained by relating the amount of creatinine filtered by the glomerulus per unit of time to the concentration of creatinine in the serum. The technic is simple and practical for routine use. Since 1948, the creatinine clearance determination has been used extensively at the University of California Medical Center for the evaluation of renal function. The present report reviews our selected experience with this procedure during the past 14 years. Clinical examples are used to show that the Ccr is a more accurate index of glomerular filtration than the concentration of any of the nonprotein nitrogen components of the blood.

Tjan, Hoen Lay; Tobias, James; Levin, Ralph; Hopper, James

1963-01-01

46

Uric acid provides antioxidant protection against ozone-induced damage for nucleobase, membranes and erythrocytes  

SciTech Connect

The ozone-induced degradation rates of various purine bases, hydroxylated purine compounds, pyrimidine bases, and uric acid were compared. Of the compounds examined, uric acid was the one most readily degraded while the parent compounds, purine and pyrimidine, were the ones most resistant to ozonation. When the breakdown of hydroxylated purines was studied, it was determined that the more OH substituents on the purine, the more readily it was degraded. Because of the preferential attack by ozone on uric acid in solutions containing a nucleic acid base plus uric acid, the presence of the uric acid had a sparing effect on the base. This effect was readily apparent for guanine, thymine, and uracil which were the bases more labile to ozone. Two of the ozonation products of uric acid were identified as allantoin and urea. Ozonation of bovine and swine erythrocyte suspensions resulted in oxidation of oxyhemoglobin to methemoglobin, formation of thiobarbituric acid-reactive materials-a measure of lipid oxidation- and lysis of the red cells. Each of these changes was inhibited by the presence of uric acid in the solution during ozonation.

Meadows, J.R.

1986-01-01

47

Molecular Structure of Urea nitrate  

NSDL National Science Digital Library

Urea nitrate is a plastic explosive used for the charge on a nuclear weapon or as a component of a non-nuclear high explosive. It can also be used as a catalyst in Diels-Alder reactions of aromatic amines. It is favored by amateur terrorists because it is fairly easily derived from urea fertilizers or made by combining nitric and uric acids. Nitric acid can be found as waste from several industrial processes, while urea can be found as biological waste from most animals (in the form of urine). Thus, it provides similar explosive power, but lower cost, as TNT. Additionally, it is quite stable, with low friction and shock sensitivity, making it somewhat stable to work with, but also causing it to require an additional more unstable chemical detonator, called a booster, for use as a high explosive. However, in use as an industrial explosive, urea nitrate is used as a sensitizer to a less reactive fuel. It was the main component of the explosive used in the 1993 bombing of the World Trade Center.

2002-09-23

48

Antioxidation mechanisms of uric acid  

SciTech Connect

One-electron oxidation of uric acid generates the urate radical, which was studied in aqueous solution by pulse radiolysis and oxygen-uptake measurements. Acid-base properties of the uric acid radical were determined, i.e., pK{sub a1} = 3.1 {plus minus} 0.1 and pK{sub a2} = 9.5 {plus minus} 0.1. The reaction of the radical with oxygen was too slow to be measured, k < 10{sup {minus}2} dm{sup 3} mol{sup {minus}1} s{sup {minus}1}. The one-electron-redox potential vs NHE, E{sub 7} = 0.59 V, was derived from the pH dependence of the redox potential, which was fitted through the values measured at pH 7 and 8.9 and those previously determined at pH 13. Rapid reactions of uric acid with oxidizing species and peroxy radicals were indicative of uric acid as a possible water-soluble physiological antioxidant. Rapid reaction of uric acid with the guanyl radical indicates that uric acid may also act as a repair agent of oxidative damage to DNA bases.

Simic, M.G. (National Institute of Standards and Technology, Gaithersburg, MD (USA)); Jovanovic, S.V. (Boris Kidric Institute of Nuclear Sciences, Belgrade (Yugoslavia))

1989-07-19

49

Approach to managing elevated creatinine.  

PubMed Central

OBJECTIVE: To describe a systematic approach to finding the underlying cause of an elevated creatinine level. QUALITY OF EVIDENCE: This diagnostic approach is based on a synthesis of information from reference works on nephrology, articles found through a MEDLINE search, and the author's personal experience. MAIN MESSAGE: Elevated creatinine levels suggest the differential diagnosis of renal failure (RF). History and a complete physical examination are important, keeping in mind that RF is often asymptomatic in the early stages. After repeating the creatinine test to verify results, baseline tests should be ordered to identify the cause of the RF. Comparing results of serial tests is essential for determining whether RF is acute or chronic, stable or progressive. An ultrasound scan is particularly useful for eliminating an obstructive cause; the size of the kidney can indicate whether disease is acute or chronic. Complementary blood tests and imaging studies might be useful. CONCLUSION: Diagnosing and managing RF can appear complex, but a systematic approach will help you find the cause and treat the condition.

Tremblay, Richard

2004-01-01

50

Creatinine in the dog: a review.  

PubMed

Creatinine is the analyte most frequently measured in human and veterinary clinical chemistry laboratories as an indirect measure of glomerular filtration rate (GFR). Although creatinine metabolism and the difficulties of creatinine measurement have been reviewed in human medicine, similar reviews are lacking in veterinary medicine. The aim of this review is to summarize information and data about creatinine metabolism, measurement, and diagnostic significance in the dog. Plasma creatinine originates from the degradation of creatine and creatine phosphate, which are present mainly in muscle and in food. Creatinine is cleared by glomerular filtration with negligible renal secretion and extrarenal metabolism, and its clearance is a good estimate of GFR. Plasma and urine creatinine measurements are based on the nonspecific Jaffé reaction or specific enzymatic reactions; lack of assay accuracy precludes proper interlaboratory comparison of results. Preanalytical factors such as age and breed can have an impact on plasma creatinine (P-creatinine) concentration, while many intraindividual factors of variation have little effect. Dehydration and drugs mainly affect P-creatinine concentration in dogs by decreasing GFR. P-creatinine is increased in renal failure, whatever its cause, and correlates with a decrease in GFR according to a curvilinear relationship, such that P-creatinine is insensitive for detecting moderate decreases of GFR or for monitoring progression of GFR in dogs with severely reduced kidney function. Low sensitivity can be obviated by determining endogenous or exogenous clearance rates of creatinine. A technique for determining plasma clearance following IV bolus injection of exogenous creatinine and subsequent serial measurement of P-creatinine does not require urine collection and with additional studies may become an established technique for creatinine clearance in dogs. PMID:14655101

Braun, J P; Lefebvre, H P; Watson, A D J

2003-01-01

51

Management of uric acid stone.  

PubMed

Uric acid stones are the most readily dissolvable of all types of urinary stones. By maintaining urinary pH between 6.2-6.8 with the use of sodium acid citrate or uralyt-U and reducing serum uric acid by allopurinol, we tried to dissolve 107 stones in 67 patients. Ninety three (86.9%) stones were dissolved and 6 (5.6%) passed spontaneously within a period of one year. Eight (7.5%) stones were removed surgically or with ESWL. Five (7.5%) patients had stone recurrence over a period of 3 years follow-up. Serum uric acid was raised in 19 (28.5%) and urinary uric acid in 12 (18%) patients while urinary pH was low in 46 (69%) patients. For uncomplicated uric acid stones oral chemolysis on an out-patient basis is the treatment of choice. It is simple, safe and inexpensive. However, it requires rigid compliance by the patient and strict follow-up by ultrasonography (JPMA 42: 153, 1992). PMID:1404830

Chugtai, M N; Khan, F A; Kaleem, M; Ahmed, M

1992-07-01

52

Association of serum uric Acid with level of blood pressure in type 2 diabetic patients.  

PubMed

This study was conducted to investigate the association between serum uric acid level and blood pressure in type 2 diabetes mellitus. Sixty patients with type 2 diabetes mellitus were enrolled to the study. None of the patients had a history of gout, were treated with allopurinol, or were treated with antihypertensive drugs previously. The mean duration of DM was 9.2 ± 4.9 years. The mean serum creatinine level was 0.98 ± 0.22 mg/dL, and the mean serum UA level was 4.4 ± 1.2 mg/dL. The mean protein level in 24-hour urine sample was 388 ± 22 mg/d. The mean systolic and diastolic blood pressure values were 133.0 ± 13.0 mm Hg and 84.0 ± 7.4 mm Hg, respectively. There was no significant difference in levels of serum uric acid, hemoglobin A1c, serum creatinine, proteinuria, or systolic and diastolic pressure between the men and the women. A significant positive correlation was seen between serum UA and systolic (r = 0.312, P = .02) and diastolic blood pressure (r = 0.297, P = .03). Results of this study suggest that serum uric acid had a strong association with levels of systolic and diastolic blood pressure in type 2 diabetic patients. More attention to the serum uric acid level and treatment of hyperuricemia could halt the progress of diabetic nephropathy. PMID:24685739

Rafieian-Kopaei, Mahmoud; Behradmanesh, Saeed; Kheiri, Soleiman; Nasri, Hamid

2014-03-01

53

Pathophysiologic basis for normouricosuric uric acid nephrolithiasis  

Microsoft Academic Search

Pathophysiologic basis for normouricosuric uric acid nephrolithiasis.Background:Low urinary pH is the commonest and by far the most important factor in uric acid nephrolithiasis but the reason(s) for this defect is (are) unknown. Patients with uric acid nephrolithaisis have normal acid-base parameters according conventional clinical tests.Methods:We studied steady-state plasma and urinary parameters of acid-base balance in subjects with normouricosuric pure uric

Khashayar Sakhaee; Beverley Adams-Huet; Orson W. Moe; Charles Y. C. Pak

2002-01-01

54

Biochemical profile of idiopathic uric acid nephrolithiasis  

Microsoft Academic Search

Biochemical profile of idiopathic uric acid nephrolithiasis.BackgroundThe objective of this study was to elucidate a biochemical profile of patients with idiopathic uric acid nephrolithiasis, without secondary causes (such as dehydration or diarrhea). Study subjects comprised 56 patients with idiopathic uric acid nephrolithiasis (UA stone group) who underwent a full outpatient evaluation. The control group was composed of 54 with absorptive

Charles YC Pak; Khashayar Sakhaee; Roy D Peterson; John R Poindexter; William H Frawley

2001-01-01

55

Online measurement of urea concentration in spent dialysate during hemodialysis  

NASA Astrophysics Data System (ADS)

We describe on-line optical measurements of urea concentration during the regular hemodialysis treatment of several patients. The spectral measurements were performed in the effluent dialysate stream after the dialysis membrane using an FTIR spectrometer equipped with a flow-through cell. Spectra were recorded across the 5000-4000 cm-1 (2.0-2.5 micrometers at 1-minute intervals. Optically determined concentrations matched concentrations obtained from standard chemical assays with a root-mean-square error of 0.29 mM for urea (0.8 mg/dl urea nitrogen), 0.03 mM for creatinine, 0.11 mM for lactate, and 0.22 mM for glucose. The observed concentration ranges were 0-11 mM for urea, 0-0.35 mM for creatinine, 0-0.75 mM for lactate, and 9-12.5 mM for glucose.

Olesberg, Jonathon T.; Armitage, Ben; Arnold, Mark A.; Flanigan, Michael

2002-05-01

56

Effects of profuse sweating induced by exercise on urinary uric acid excretion in a hot environment.  

PubMed

In order to determine whether exercise-induced profuse sweating could reduce urinary uric acid excretion, we simulated badminton players training and measured their uric acid in urine, sweat and blood during the training period. Thirteen male volunteers who were well-trained badminton players were recruited in this study. On the first 2 days and the last 2 days of the study period none of the subjects engaged in any intense exercise- or activity-inducing profuse sweat, but they accepted routine training 2 h per day during the middle 3 days. The results show that mean serum urate levels of thirteen volunteers rose significantly on day 4, when the concentrations increased by 18.2% over day 2 (P < 0.05). The mean ten-hour urinary uric acid excretion of seven volunteers on the 3 training days was significantly less at 178.5 micromol/day and 118.3 micromol/day than those on the preceding and subsequent days of the training days, respectively (P < 0.05). Furthermore, for six volunteers, the mean ratio of clearance of uric acid to creatinine was 6.6% on day 2, which significantly decreased to 5.4% on day 4 (P < 0.05). It is concluded profuse sweating exercise results in a decrease of urinary uric acid excretion amounts and leads to increased serum uric acid after the exercise. We suggest that persons who take vigorous exercise or are exposed to hot environments need drinking enough fluids to prevent dehydration and maintain adequate urinary output. People with profuse sweat after rigorous exercise are recommended taking sports drinks containing abundant sodium in order to decrease serum uric acid. PMID:21793335

Huang, Li-Ling; Huang, Chien-Tsai; Chen, Mei-Lien; Mao, I-Fang

2010-08-31

57

21 CFR 862.1225 - Creatinine test system.  

Code of Federal Regulations, 2010 CFR

...862.1225 Creatinine test system. (a) Identification. A creatinine test system is a device intended to measure creatinine levels in plasma and urine. Creatinine measurements are used in the diagnosis and treatment of renal...

2009-04-01

58

21 CFR 862.1225 - Creatinine test system.  

Code of Federal Regulations, 2010 CFR

...862.1225 Creatinine test system. (a) Identification. A creatinine test system is a device intended to measure creatinine levels in plasma and urine. Creatinine measurements are used in the diagnosis and treatment of renal...

2010-04-01

59

Association between SLC2A9 transporter gene variants and uric acid phenotypes in African American and white families  

PubMed Central

Objectives. SLC2A9 gene variants associate with serum uric acid in white populations, but little is known about African American populations. Since SLC2A9 is a transporter, gene variants may be expected to associate more closely with the fractional excretion of urate, a measure of renal tubular transport, than with serum uric acid, which is influenced by production and extrarenal clearance. Methods. Genotypes of single nucleotide polymorphisms (SNPs) distributed across the SLC2A9 gene were obtained in the Genetic Epidemiology Network of Arteriopathy cohorts. The associations of SNPs with serum uric acid, fractional excretion of urate and urine urate-to-creatinine ratio were assessed with adjustments for age, sex, diuretic use, BMI, homocysteine and triglycerides. Results. We identified SLC2A9 gene variants that were associated with serum uric acid in 1155 African American subjects (53 SNPs) and 1132 white subjects (63 SNPs). The most statistically significant SNPs in African American subjects (rs13113918) and white subjects (rs11723439) were in the latter half of the gene and explained 2.7 and 2.8% of the variation in serum uric acid, respectively. After adjustment for this SNP in African Americans, 0.9% of the variation in serum uric acid was explained by an SNP (rs1568318) in the first half of the gene. Unexpectedly, SLC2A9 gene variants had stronger associations with serum uric acid than with fractional excretion of urate. Conclusions. These findings support two different loci by which SLC2A9 variants affect uric acid levels in African Americans and suggest SLC2A9 variants affect serum uric acid level via renal and extrarenal clearance.

de Andrade, Mariza; Matsumoto, Martha; Mosley, Tom H.; Kardia, Sharon; Turner, Stephen T.

2011-01-01

60

Higher Serum Creatinine Concentrations in Black Patients with Chronic Kidney Disease: Beyond Nutritional Status and Body Composition  

PubMed Central

Background and objectives: Serum creatinine concentrations tend to be higher in black than white individuals and people of other races or ethnicities. These differences have been assumed to be largely related to race-related differences in body composition, especially muscle mass. Design, setting, participants, & measurements: In a diverse population of hemodialysis patients, we compared mean serum creatinine concentrations in black versus nonblack patients, adjusting for case mix (age, gender, diabetes, and dialysis vintage), body size (height, weight), laboratory parameters of nutritional status (albumin, predialysis blood urea nitrogen, transferrin, phosphorus, glucose), dialysis dosage (urea reduction ratio), and parameters of bioelectrical impedance (resistance and reactance), proxies for body composition. Results: Adjusted mean serum creatinine concentrations were significantly higher in black versus nonblack patients (11.7 versus 10.0 mg/dl; P < 0.0001). Black patients were roughly four-fold more likely to have a serum creatinine concentration >10 mg/dl and six-fold more likely to have a serum creatinine concentration >15 mg/dl. Higher serum creatinine concentrations were associated with a lower relative risk for death (0.93; 95% confidence interval 0.88 to 0.98 per mg/dl); the association was slightly more pronounced among nonblack patients. Conclusions: Serum creatinine concentrations are significantly higher in black compared with nonblack hemodialysis patients; these differences are not readily explained by differences in nutritional status or body composition.

Hsu, Joy; Johansen, Kirsten L.; Hsu, Chi-yuan; Kaysen, George A.; Chertow, Glenn M.

2008-01-01

61

UREA INFRASTRUCTURE FOR UREA SCR NOX REDUCTION  

SciTech Connect

Urea SCR is currently the only proven NOX aftertreatment for diesel engines - high NOX reduction possible - some SCR catalyst systems are robust against fuel sulfur - durability has been demonstrated - many systems in the field - long history in other markets - Major limitations to acceptance - distribution of urea solution to end user - ensuring that urea solution is added to vehicle.

Bunting, Bruce G.

2000-08-20

62

Retooling the creatinine clearance equation to estimate kinetic GFR when the plasma creatinine is changing acutely.  

PubMed

It is often desirable to estimate the GFR (eGFR) at the bedside to assess AKI or renal recovery. Current eGFR equations estimate kidney function when the plasma creatinine is stable, but do not work if the plasma creatinine is changing rapidly. To analyze kidney function in the acute setting, a simple formula is proposed that requires only a modest number of inputs that are readily obtainable from clinical laboratory data. The so-called kinetic eGFR (KeGFR) formula is derived from the initial creatinine content, volume of distribution, creatinine production rate, and the quantitative difference between consecutive plasma creatinines over a given time. For that period, the deciphered creatinine excretion then yields the creatinine clearance rate. The additional formula variables needed are any steady-state plasma creatinine, the corresponding eGFR by an empirical formula, and the maximum increase in creatinine per day if anuric. The kinetic formula complements clinical intuition but also adds a quantitative and visual dimension to the assessment of kidney function, demonstrated by its analysis of GFRs underlying the plasma creatinine fluctuations in several scenarios of AKI or renal recovery. Deduced from first principles regarding the physiology of creatinine balance, the KeGFR formula enhances the fundamental clearance equation with the power and versatility to estimate the kidney function when the plasma creatinine is varying acutely. PMID:23704286

Chen, Sheldon

2013-05-01

63

Uric acid and the vasculature  

Microsoft Academic Search

Hyperuricemia is a frequent finding in diseases in which the clinical manifestations are thought to be secondary to a state\\u000a of generalized vascular endothelial dysfunction and related to the cardiovascular disease present in conditions associated\\u000a with the metabolic syndrome, such as hypertension or diabetes. Traditionally, uric acid has not been given an active role\\u000a in the pathologic process underlying these

Dalila B. Corry; Michael L. Tuck

2006-01-01

64

Serum uric acid, kidney volume and progression in autosomal-dominant polycystic kidney disease  

PubMed Central

Background Hyperuricemia has been implicated in the development and progression of chronic kidney disease, both in animal experiments and in clinical studies. As a potentially modifiable risk factor, we examined whether serum uric acid levels correlate with early hypertension, kidney volume and progression to end-stage renal disease (ESRD) in autosomal-dominant polycystic kidney disease (ADPKD). Methods Retrospective analysis of a prospective observational study of the natural history of ADPKD, conducted at the University of Colorado between 1985 and 2005. Included are 680 ADPKD adults who provided data on blood pressure, renal volume, renal function, uric acid, age at the onset of ESRD or last known age without ESRD. Serum uric acid levels were examined as a continuous variable and as gender-specific quartiles. The main outcome of interest was age at the onset of ESRD; secondary outcomes were hypertension onset before age 30 years and total kidney volume (TKV) at the study visit. Results Subjects with early-onset hypertension had higher age-adjusted serum uric acid levels than those with no or late-onset hypertension despite similar creatinine clearance. After adjusting for age, gender and creatinine clearance, there was a 5.8% increase in TKV and 4.1% increase in TKV/body surface area for every 1 mg/dL increase in uric acid (P = 0.007). The multivariate-adjusted Cox regression demonstrated a greater hazard ratio for ESRD for subjects in the 4th and 3rd quartiles of uric acid compared with the 1st [4.8 (2.6–8.9; P < 0.001) and 2.9 (1.6–5.3; P < 0.001)]. Conclusions Higher serum uric acid levels are associated with earlier onset of hypertension, larger kidney volume and increased hazard for ESRD in ADPKD independent of gender, body mass index and renal function at the study visit. Randomized interventional studies will be necessary to examine whether treating hyperuricemia has a protective role in ADPKD.

Helal, Imed; McFann, Kim; Reed, Berenice; Yan, Xiang-Dong; Schrier, Robert W.; Fick-Brosnahan, Godela M.

2013-01-01

65

Quantification of urinary uric acid in the presence of thymol and thimerosal by high-performance liquid chromatography  

NASA Technical Reports Server (NTRS)

A high-performance liquid chromatographic method was developed as an alternative to automated enzymatic analysis of uric acid in human urine preserved with thymol and/or thimerosal. Uric acid (tR = 10 min) and creatinine (tR = 5 min) were separated and quantified during isocratic elution (0.025 M acetate buffer, pH 4.5) from a mu Bondapak C18 column. The uric-acid peak was identified chemically by incubating urine samples with uricase. The thymol/thimerosal peak appeared at 31 min during the washing step and did not interfere with the analysis. We validated the high-performance liquid chromatographic method for linearity, precision and accuracy, and the results were found to be excellent.

Chen, Y.; Pietrzyk, R. A.; Whitson, P. A.

1997-01-01

66

Population based data on urinary excretion of calcium, magnesium, oxatate, phosphate and uric acid in children from Cimitile (southern Italy)  

Microsoft Academic Search

Population based data on 24-h urinary excretion of calcium, oxalate, magnesium, phosphate, uric acid and creatinine were collected from 220 children (aged 3–16 years) living in Cimitile, Campania, southern Italy. Mean excretion rates for 7 days were correlated with age, body weight, body mass index and height. The prevalence of hypercalciuria (>4 mg\\/kg body weight) and of hyperoxaluria (>60 mg\\/day)

Natale G. De Santot; Biagio Di Iorio; Giovambattista Capasso; Carmine Paduanol; Rose Stamler; Craig B. Langman; Jeremiah Stamler

1992-01-01

67

Salivary Creatinine Estimation as an Alternative to Serum Creatinine in Chronic Kidney Disease Patients  

PubMed Central

Context. Sampling blood for serum analysis is an invasive procedure. A noninvasive alternative would be beneficial to patients and health care professionals. Aim. To correlate serum and salivary creatinine levels and evaluate the role of saliva as a noninvasive alternative to serum for creatinine estimation in chronic kidney disease patients. Study Design. Case-control study. Methods. Blood and saliva samples were collected from 37 healthy individuals and 105 chronic kidney disease patients. Serum and salivary creatinine levels were estimated using automatic analyser. Statistical Analysis. The serum and salivary creatinine levels between controls and cases were compared using t-test. Correlation between serum and salivary creatinine was obtained in controls and cases using Pearson correlation coefficient. Receiver operating characteristic analysis was done to assess the diagnostic performance of salivary creatinine. Cut-off values were established for salivary creatinine. Results. Serum and salivary creatinine levels were significantly higher in CKD patients than controls. The correlation was negative in controls and positive in cases. Area under the curve for salivary creatinine was found to be 0.967. A cut-off value of 0.2?mg/dL gave a sensitivity of 97.1% and specificity of 86.5%. Conclusion. Saliva can be used as a noninvasive alternative to serum for creatinine estimation.

Venkatapathy, Ramesh; Govindarajan, Vasupradha; Oza, Nirima; Parameswaran, Sreejith; Pennagaram Dhanasekaran, Balamurali; Prashad, Karthikshree V.

2014-01-01

68

Urine Albumin and Albumin/ Creatinine Ratio  

MedlinePLUS

... may also vary. Creatinine, a byproduct of muscle metabolism, is normally excreted into the urine at a ... exercise, blood in the urine, urinary tract infection , dehydration , and some drugs. ^ Back to top Ask a ...

69

Type 2 Diabetes and Uric Acid Nephrolithiasis  

NASA Astrophysics Data System (ADS)

Type 2 diabetes is associated with an increased propensity for uric acid nephrolithiasis. In individuals with diabetes, this increased risk is due to a lower urine pH that results from obesity, dietary factors, and impaired renal ammoniagenesis. The epidemiology and pathogenesis of uric acid stone disease in patients with diabetes are hereby reviewed, and potential molecular mechanisms are proposed.

Maalouf, Naim M.

2008-09-01

70

Effect of sodium chloride intake on urine volume, urinary urea excretion, and milk urea concentration in lactating dairy cattle.  

PubMed

Milk urea nitrogen (MUN; mg of N/dL) has been shown to be related to excretion of urinary urea N (UUN; g of N/d) and total excretion of urinary N (UN; g of N/d) in dairy cows. In the present experiment, it was hypothesized that MUN and the relationship between MUN and UUN or UN is affected by urine volume as a result of dietary sodium chloride intake. Twelve lactating Holstein-Friesian dairy cows (mean ± SD: milk production 28.1±3.23 kg/d and 190±41 d in milk), of which 4 were fitted with catheters in the urine bladder and jugular vein, were randomly assigned to 4 dietary levels of sodium chloride (3, 9, 14, and 19 g of Na/kg of DM) according to a triple 4×4 Latin square design. Cows were fed at 95% of ad libitum intake, excluding salt addition. Milk was analyzed for MUN and protein content; urine was analyzed for total N, urea, and creatinine content; feces were analyzed for total N and DM content; and blood plasma was analyzed for urea and creatinine content. Creatinine clearance rate (CCR; L/min) and renal urea reabsorption ratio were estimated based on plasma concentrations of urea and creatinine, and total excretion of urea and creatinine in urine. Intake of DM and N, milk production, and milk protein content were (mean ± SD), on average, 21.4±1.24 kg/d, 522±32.0 g/d, 25.4±2.53 kg/d, and 3.64±0.186%, respectively. A linear relationship was found between Na intake and urine production [urine (kg/d; mean ± SE)=7.5±4.33+0.136±0.0143 × Na intake (g/d)] and between Na intake and MUN [MUN (mg/dL; mean ± SE)=13.5±0.35-0.0068±0.00104 × Na intake (g/d)]. Despite the decrease in MUN with increased Na intake, UN excretion increased linearly with Na intake. Excretion of UUN was not affected by dietary Na content. A linear plateau relationship was observed between CCR and renal urea reabsorption. An increase in CCR coincided with an increase in calculated renal urea reabsorption until a CCR breakpoint value (mean ± SD) of 1.56±0.063 L/min was reached. We conclude that Na intake is negatively related to MUN, whereas UUN is not affected. Variation in mineral intake levels that affect urine volume should, therefore, be taken into account when using MUN as an indicator of UUN in dairy cattle. PMID:23063155

Spek, J W; Bannink, A; Gort, G; Hendriks, W H; Dijkstra, J

2012-12-01

71

Protein: creatinine and trypsin inhibitor: creatinine ratios in the urine of marathon runners  

Microsoft Academic Search

Summary  We measured changes in the protein: creatinine and trypsin inhibitor: creatinine ratios in the urine of six male marathon runners. Samples of urine were collected before the run, immediately after the run and in 6-h collections for 2 days. We found the greatest increase in the protein: creatinine ratio (2.6 times greater) in urine collected immediately after the run and

Jacek Borkowski; Krzysztof A. Sobiech

1990-01-01

72

Synthesis of creatinine-imprinted poly(beta-cyclodextrin) for the specific binding of creatinine.  

PubMed

An artificial receptor for creatinine was synthesized by the method of molecularly imprinted polymer (MIP). beta-Cyclodextrin was used as a monomer cross-linked with epichlorohydrin in the presence of creatinine, which was a template for the imprinting. Different molar ratios of monomer to template were used to synthesize the polymers so that better specific adsorption ability towards creatinine could be achieved. The results showed that to carry out the polymerization with a molar ratio of monomer to template of 3:2 and monomer to cross-linking agent of 1:10 was proper. N-hydroxysuccinimide and 2-pyrrolinidone were used as the analogues of creatinine in the adsorption experiments of multi-component solutions to reveal the specific recognition ability of the molecularly imprinted poly(beta-cyclodextrin) (poly(beta-CD)) for the template molecule, creatinine. One such detection interference of creatinine was creatine, which also co-exists in serum. Hence, adsorption experiments of creatinine/creatine binary mixture were also carried out to investigate and confirm the specific binding of the creatinine-imprinted poly(beta-cyclodextrin) towards creatinine. The hydroxyl groups of the imprinted poly(beta-CD) was further capped by chlorotrimethylsilane (CTMS) to investigate the interaction between creatinine and the imprinted poly(beta-CD). The adsorption resulting from the mixture solution by MIPs suggested that the creatinine-imprinted poly(beta-CD) demonstrated superior binding effect for the target molecule, creatinine, rather than creatine, N-hydroxysuccinimide and 2-pyrrolinidone. PMID:15585280

Tsai, Hsuan-Ang; Syu, Mei-Jywan

2005-05-01

73

A stable three-enzyme creatinine biosensor. 3. Immobilization of creatinine amidohydrolase and sensor development  

Microsoft Academic Search

We describe the development of an extended use amperometric three-enzyme creatinine biosensor and the successful chemical modification and immobilization of the enzyme creatinine amidohydrolase using polyurethane prepolymers. Creatinine amidohydrolase is significantly stabilized by immobilization in polyurethane polymers. The half-life increases from six to more than 80 days in buffer at 37°C. The effect of silver ions leached from amperometric reference

Jason A. Berberich; Andy Chan; Mark Boden; Alan J. Russell

2005-01-01

74

Impact of smoking on microalbuminuria and urinary albumin creatinine ratio in non-diabetic normotensive smokers  

PubMed Central

Smoking is associated with an excessive morbidity and mortality from a variety of diseases. The aim of this study was to find out the effects of smoking on renal function study in non-diabetic, normotensive subjects. A community-based, prospective, cross-sectional cohort study was conducted on 120 subjects; 80 (66.66%) were smokers and 40 (33.33%) age matched non-smokers; with age range of 30 to 70 years. Measurement of fasting sugar, urea, creatinine, lipids and one time screening of urinary albumin and urinary creatinine was done. Smokers had significantly higher urinary albumin and albumin creatinine ratio (ACR) (52.84 ± 46.42 mg/L, 93.98 ± 78.68 ?g/mg) than non-smokers (19.25 ± 7.77 mg/L, 18.99 ± 6.65 ?g/mg), respectively (P =< 0.001, P =< 0.001). Microalbuminuria and urinary ACR level were directly related to the amount of smoking (pack-years). Among smokers, 73 (91.25%) had microalbuminuria (>20 mg/L) and 64 (80%) had increased urinary ACR (>30 ?g/mg). Smoker had significantly lower high-density lipoprotein level (36.66 ± 10.28 mg/dl) compared to non-smokers (41.22 ± 11.72 mg/dl) (P = 0.031). Urea, creatinine, creatinine clearance, total cholesterol, low density lipoprotein, triglyceride levels were comparable (p = NS). In conclusion, smokers have a 4-fold higher prevalence of microalbuminuria than non-smokers.

Gupta, R. K.; Gupta, R.; Maheshwari, V. D.; Mawliya, M.

2014-01-01

75

Graphene Doped Molecularly Imprinted Electrochemical Sensor for Uric Acid  

Microsoft Academic Search

A highly sensitive uric acid molecularly imprinted electrochemical sensor was prepared by using graphene doped chitosan as functional matrix and uric acid as template molecule and electrodeposition technique was used to form a controllable graphene – chitosan –uric acid composited film on glassy carbon electrode whose uric acid was removed via electrochemical induce elution. Under the optimized preparation and detection

Huiting Lian; Zhaohui Sun; Xiangying Sun; Bin Liu

2012-01-01

76

Randomized Controlled Trial of Febuxostat Versus Allopurinol or Placebo in Individuals with Higher Urinary Uric Acid Excretion and Calcium Stones  

PubMed Central

Summary Background and objectives Higher urinary uric acid excretion is a suspected risk factor for calcium oxalate stone formation. Febuxostat, a xanthine oxidoreductase inhibitor, is effective in lowering serum urate concentration and urinary uric acid excretion in healthy volunteers and people with gout. This work studied whether febuxostat, compared with allopurinol and placebo, would reduce 24-hour urinary uric acid excretion and prevent stone growth or new stone formation. Design, setting, participants, & measurements In this 6-month, double-blind, multicenter, randomized controlled trial, hyperuricosuric participants with a recent history of calcium stones and one or more radio-opaque calcium stone ?3 mm (as seen by multidetector computed tomography) received daily febuxostat at 80 mg, allopurinol at 300 mg, or placebo. The primary end point was percent change from baseline to month 6 in 24-hour urinary uric acid. Secondary end points included percent change from baseline to month 6 in size of index stone and change from baseline in the mean number of stones and 24-hour creatinine clearance. Results Of 99 enrolled participants, 86 participants completed the study. Febuxostat led to significantly greater reduction in 24-hour urinary uric acid (?58.6%) than either allopurinol (?36.4%; P=0.003) or placebo (?12.7%; P<0.001). Percent change from baseline in the size of the largest calcium stone was not different with febuxostat compared with allopurinol or placebo. There was no change in stone size, stone number, or renal function. No new safety concerns were noted for either drug. Conclusions Febuxostat (80 mg) lowered 24-hour urinary uric acid significantly more than allopurinol (300 mg) in stone formers with higher urinary uric acid excretion after 6 months of treatment. There was no change in stone size or number over the 6-month period.

MacDonald, Patricia A.; Gunawardhana, Lhanoo; Chefo, Solomon; McLean, Lachy

2013-01-01

77

Biosensors and flow-through system for the determination of creatinine in hemodialysate.  

PubMed

Biosensors for the determination of creatinine have been developed and integrated into a flow-through system. The sensors are based on a screen-printed three electrode transducer with a platinum working electrode. Applying the multi-enzyme sequence of creatininase (CA), creatinase (CI) and sarcosine oxidase (SO) hydrogen peroxide has been detected amperometrically. An optimal enzyme load was found to be 4.4 U/0.28 U/0.20 U (CA/CI/SO) and 0.28 U/0.20 U (CI/SO) per electrode for the creatinine sensor and for the creatine sensor, respectively. Among a variety of polymers Nafion has shown the highest efficiency to exclude interfering substances like ascorbic acid, acetaminophen and uric acid. First determinations of creatinine in dialysate samples obtained during hemodialysis treatments have shown a good correlation to the conventional methods, the Jaffé reaction (y=0.945x+ 2.8, R=0.9882, n=9) and the enzymatic photometric method (y=0.891x+3.5, R=0.9917, n=9). PMID:11936100

Erlenkötter, Ansgar; Fobker, Manfred; Chemnitius, Gabriele-Christine

2002-01-01

78

Down-regulation of Hepatic Urea Synthesis by Oxypurines  

PubMed Central

We previously reported that isobutylmethylxanthine (IBMX), a derivative of oxypurine, inhibits citrulline synthesis by an as yet unknown mechanism. Here, we demonstrate that IBMX and other oxypurines containing a 2,6-dione group interfere with the binding of glutamate to the active site of N-acetylglutamate synthetase (NAGS), thereby decreasing synthesis of N-acetylglutamate, the obligatory activator of carbamoyl phosphate synthase-1 (CPS1). The result is reduction of citrulline and urea synthesis. Experiments were performed with 15N-labeled substrates, purified hepatic CPS1, and recombinant mouse NAGS as well as isolated mitochondria. We also used isolated hepatocytes to examine the action of various oxypurines on ureagenesis and to assess the ameliorating affect of N-carbamylglutamate and/or l-arginine on NAGS inhibition. Among various oxypurines tested, only IBMX, xanthine, or uric acid significantly increased the apparent Km for glutamate and decreased velocity of NAGS, with little effect on CPS1. The inhibition of NAGS is time- and dose-dependent and leads to decreased formation of the CPS1-N-acetylglutamate complex and consequent inhibition of citrulline and urea synthesis. However, such inhibition was reversed by supplementation with N-carbamylglutamate. The data demonstrate that xanthine and uric acid, both physiologically occurring oxypurines, inhibit the hepatic synthesis of N-acetylglutamate. An important and novel concept emerging from this study is that xanthine and/or uric acid may have a role in the regulation of ureagenesis and, thus, nitrogen homeostasis in normal and disease states.

Nissim, Itzhak; Horyn, Oksana; Nissim, Ilana; Daikhin, Yevgeny; Caldovic, Ljubica; Barcelona, Belen; Cervera, Javier; Tuchman, Mendel; Yudkoff, Marc

2011-01-01

79

Amylase creatinine clearance ratio after biliary surgery  

Microsoft Academic Search

The amylase creatinine clearance ratio (ACCR) is considered to be a more sensitive index of acute pancreatitis than the serum amylase level. Serial ACCR estimations were undertaken in 25 patients undergoing an elective cholecystectomy. Using accepted criteria, 28% of these patients developed, in the postoperative period, biochemical evidence of pancreatic gland damage, although the serum amylase level remained normal. This

L A Donaldson; W McIntosh; S N Joffe

1977-01-01

80

Reaction of Uric Acid with Peroxynitrite and Implications for the Mechanism of Neuroprotection by Uric Acid  

Microsoft Academic Search

Peroxynitrite, a biological oxidant formed from the reaction of nitric oxide with the superoxide radical, is associated with many pathologies, including neurodegenerative diseases, such as multiple sclerosis (MS). Gout (hyperuricemic) and MS are almost mutually exclusive, and uric acid has therapeutic effects in mice with experimental allergic encephalomyelitis, an animal disease that models MS. This evidence suggests that uric acid

Giuseppe L. Squadrito; Rafael Cueto; Andres E. Splenser; Athanasios Valavanidis; Houwen Zhang; Rao M. Uppu; William A. Pryor

2000-01-01

81

Replication of the effect of SLC2A9 genetic variation on serum uric acid levels in American Indians.  

PubMed

Increased serum uric acid (SUA) or hyperuricemia, a risk factor for gout, renal and cardiovascular diseases, is caused by either increased production or decreased excretion of uric acid or a mix of both. The solute carrier protein 2 family, member 9 (SLC2A9) gene encodes a transporter that mediates urate flux across the renal proximal tubule. Genome-wide association studies have consistently shown the association of single-nucleotide polymorphisms in this gene with SUA in majority populations. American Indian participants of the Strong Heart Family Study, belonging to multigenerational families, have high prevalence of hyperuricemia. We conducted measured genotype analyses, based on variance components decomposition method and accounting for family relationships, to assess whether the association between SUA and SLC2A9 gene polymorphisms generalized to American Indians (n=3604) of this study. Seven polymorphisms were selected for genotyping based on their association with SUA levels in other populations. A strong association was found between SLC2A9 gene polymorphisms and SUA in all centers combined (P-values: 1.3 × 10(-31)-5.1 × 10(-23)) and also when stratified by recruitment center; P-values: 1.2 × 10(-14)-1.0 × 10(-5). These polymorphisms were also associated with the estimated glomerular filtration rate and serum creatinine but not albumin-creatinine ratio. In summary, the association of polymorphisms in the uric acid transporter gene with SUA levels extends to a new population of American Indians. PMID:24301058

Voruganti, V Saroja; Franceschini, Nora; Haack, Karin; Laston, Sandra; MacCluer, Jean W; Umans, Jason G; Comuzzie, Anthony G; North, Kari E; Cole, Shelley A

2014-07-01

82

A review on creatinine measurement techniques.  

PubMed

This paper reviews the entire recent global tendency for creatinine measurement. Creatinine biosensors involve complex relationships between biology and micro-mechatronics to which the blood is subjected. Comparison between new and old methods shows that new techniques (e.g. Molecular Imprinted Polymers based algorithms) are better than old methods (e.g. Elisa) in terms of stability and linear range. All methods and their details for serum, plasma, urine and blood samples are surveyed. They are categorized into five main algorithms: optical, electrochemical, impedometrical, Ion Selective Field-Effect Transistor (ISFET) based technique and chromatography. Response time, detection limit, linear range and selectivity of reported sensors are discussed. Potentiometric measurement technique has the lowest response time of 4-10 s and the lowest detection limit of 0.28 nmol L(-1) belongs to chromatographic technique. Comparison between various techniques of measurements indicates that the best selectivity belongs to MIP based and chromatographic techniques. PMID:22841040

Mohabbati-Kalejahi, Elham; Azimirad, Vahid; Bahrami, Manouchehr; Ganbari, Ahmad

2012-08-15

83

The Epidemiology of Uric Acid and Fructose  

PubMed Central

During the past few decades, the mean serum uric acid levels and the prevalence of hyperuricemia in the general population appear to have increased. Correspondingly, the prevalence and incidence of gout have doubled. Potential reasons behind these trends include the increasing prevalence of obesity and metabolic syndrome, western life-style factors, increased prevalence of medical conditions (e.g. renal conditions, hypertension, and cardiovascular disorders) and use of medications that increase uric acid levels (e.g. diuretics and low-dose aspirin). The substantial increase in sugar-sweetened soft drinks and associated fructose consumption has also coincided with the secular trend of hyperuricemia and gout. Recently, several large-scale epidemiologic studies have clarified a number of these long-suspected risk factors in relation with hyperuricemia and gout. Furthermore, recent studies have illuminated the substantial comorbidities of hyperuricemia and gout, particularly metabolic-cardiovascular-renal conditions. While many prospective studies have suggested an independent association between serum uric acid levels and the future risk of cardiovascular-metabolic morbidities and mortality, only a limited number of randomized clinical trials and observational studies have recently demonstrated that the use of allopurinol can be beneficial against these outcomes. As these data are scarce and the effects of allopurinol might not be limited to lowering serum uric acid levels, the potential causal role of uric acid on these outcomes remains to be clarified with further studies.

Rho, Young Hee; Zhu, Yanyan; Choi, Hyon K.

2011-01-01

84

Uric Acid Nephrolithiasis: A Systemic Metabolic Disorder  

PubMed Central

Uric acid nephrolithiasis is characteristically a manifestation of a systemic metabolic disorder. It has a prevalence of about 10% among all stone formers, the third most common type of kidney stone in the industrialized world. Uric acid stones form primarily due to an unduly acid urine; less deciding factors are hyperuricosuria and a low urine volume. The vast majority of uric acid stone formers have the metabolic syndrome, and not infrequently, clinical gout is present as well. A universal finding is a low baseline urine pH plus insufficient production of urinary ammonium buffer. Persons with gastrointestinal disorders, in particular chronic diarrhea or ostomies, and patients with malignancies with a large tumor mass and high cell turnover comprise a less common but nevertheless important subset. Pure uric acid stones are radiolucent but well visualized on renal ultrasound. A 24 h urine collection for stone risk analysis provides essential insight into the pathophysiology of stone formation and may guide therapy. Management includes a liberal fluid intake and dietary modification. Potassium citrate to alkalinize the urine to a goal pH between 6 and 6.5 is essential, as undissociated uric acid deprotonates into its much more soluble urate form.

Moe, Orson W.

2014-01-01

85

Free radical metabolite of uric acid.  

PubMed

Uric acid has previously been shown to act as a water-soluble antioxidant. Although the antioxidant activity of uric acid has been attributed to its ability to scavenge free radicals, the one-electron uric acid oxidation product of such a scavenging reaction has not been detected. It order to determine whether a free radical metabolite of uric acid could be formed via one-electron redox processes, we oxidized uric acid with potassium permanganate, horseradish peroxidase/hydrogen peroxide, and hematin/hydrogen peroxide systems. With the use of the rapid-mixing, continuous-flow electron spin resonance technique, we were able to detect the urate anion free radical in all three radical-generating systems. Based on N15-isotopic-labeling experiments, we show that the unpaired electron of this radical is located primarily on the five-membered ring of the purine structure. We were also able to demonstrate that this radical could be scavenged by ascorbic acid. PMID:2828349

Maples, K R; Mason, R P

1988-02-01

86

Quantification of creatinine in biological samples based on the pseudoenzyme activity of copper-creatinine complex.  

PubMed

Glomerular filtration rate (GFR), the marker of chronic kidney disease can be analyzed by the concentration of cystatin C or creatinine and its clearance in human urine and serum samples. The determination of cystatin C alone as an indicator of GFR does not provide high accuracy, and is more expensive, thus measurement of creatinine has an important role in estimating GFR. We have made an attempt to quantify creatinine based on its pseudoenzyme activity of creatinine in the presence of copper. Creatinine in the presence of copper oxidizes paraphenylenediamine dihydrochloride (PPDD) which couples with dimethylamino benzoicacid (DMAB) giving green colored chromogenic product with maximum absorbance at 710 nm. Kinetic parameters relating this reaction were evaluated. Analytical curves of creatinine by fixed time and rate methods were linear at 8.8-530 ?mol L(-1) and 0.221-2.65 mmol L(-1), respectively. Recovery of creatinine varied from 97.8 to 107.8%. Limit of detection and limit of quantification were 2.55 and 8.52 ?mol L(-1) respectively whereas Sandell's sensitivity and molar absorption coefficient values were 0.0407 ?g cm(-2) and 0.1427×10(4) L mol(-1) cm(-1) respectively. Precision studies showed that within day imprecision was 0.745-1.26% and day-to-day imprecision was 1.55-3.65%. The proposed method was applied to human urine and serum samples and results were validated in accordance with modified Jaffe's procedure. Wide linearity ranges with good recovery, less tolerance from excipients and application of the method to serum and urine samples are the claims which ascertain much advantage to this method. PMID:22446781

Nagaraja, Padmarajaiah; Avinash, Krishnegowda; Shivakumar, Anantharaman; Krishna, Honnur

2012-06-15

87

Quantification of creatinine in biological samples based on the pseudoenzyme activity of copper-creatinine complex  

NASA Astrophysics Data System (ADS)

Glomerular filtration rate (GFR), the marker of chronic kidney disease can be analyzed by the concentration of cystatin C or creatinine and its clearance in human urine and serum samples. The determination of cystatin C alone as an indicator of GFR does not provide high accuracy, and is more expensive, thus measurement of creatinine has an important role in estimating GFR. We have made an attempt to quantify creatinine based on its pseudoenzyme activity of creatinine in the presence of copper. Creatinine in the presence of copper oxidizes paraphenylenediamine dihydrochloride (PPDD) which couples with dimethylamino benzoicacid (DMAB) giving green colored chromogenic product with maximum absorbance at 710 nm. Kinetic parameters relating this reaction were evaluated. Analytical curves of creatinine by fixed time and rate methods were linear at 8.8-530 ?mol L-1 and 0.221-2.65 mmol L-1, respectively. Recovery of creatinine varied from 97.8 to 107.8%. Limit of detection and limit of quantification were 2.55 and 8.52 ?mol L-1 respectively whereas Sandell's sensitivity and molar absorption coefficient values were 0.0407 ?g cm-2 and 0.1427 × 104 L mol-1 cm-1 respectively. Precision studies showed that within day imprecision was 0.745-1.26% and day-to-day imprecision was 1.55-3.65%. The proposed method was applied to human urine and serum samples and results were validated in accordance with modified Jaffe's procedure. Wide linearity ranges with good recovery, less tolerance from excipients and application of the method to serum and urine samples are the claims which ascertain much advantage to this method.

Nagaraja, Padmarajaiah; Avinash, Krishnegowda; Shivakumar, Anantharaman; Krishna, Honnur

88

Comparison of serum creatinine and spot urine interleukin-18 levels following radiocontrast administration.  

PubMed

Radiocontrast administration is an important cause of acute renal failure. In this study, compared the plasma creatinine levels with spot urine IL-18 levels following radiocontrast administration. Twenty patients (11 males, 9 females) underwent radiocontrast diagnostic and therapeutic-enhanced examinations. The RIN Mehran risk score was low (?5). The radiocontrast agents used were 623 mg/mL Iopromid (1.5 mL/kg), and 100 mL of 650 mg/mL meglumine diatrizoate as three-way oral and rectal contrast material for abdominal computed tomography (CT) scans. Serum blood urea nitrogen, creatinine, Na, K, Cl, Ca, P, creatinine clearance, and spot urine IL-18 levels were analyzed before and repeated at 24, 48, and 72 h after radiocontrast administration. Six and 24-h urinary IL-18 levels were measured with a human IL-18 ELISA kit following radiocontrast administration. An increase in plasma creatinine 24 and 48 h following radiocontrast administration was observed compared with precontrast values, but it was not statistically significant (P=0.052 and P=0.285, respectively). A statistically significant increase in IL-18 levels was observed at 6 and 24 h, compared with precontrast values (P=0.048 and P=0.028, respectively). A tendency for postcontrast 24-h urinary IL-18 levels to increase was observed compared with 6 h, but the increase was not statistically significant (P=0.808). Our results show that plasma creatinine starts to increase at 24(th) hour; however, spot urine IL-18 levels go up at 6(th) hour following radiocontrast administration implying urine IL-18 to be an earlier parameter for kidney injury. PMID:23087555

Turkmen, F; Isitmangil, G; Berber, I; Arslan, G; Sevinc, C; Ozdemir, A

2012-05-01

89

Preliminary investigations on a new disposable potentiometric biosensor for uric acid.  

PubMed

In this paper, uricase, catalase, and electron mediator were coimmobilized on the surface of the tin oxide (SnO2)/indium tin oxide (ITO) glass, to develop a disposable potentiometric uric acid biosensor. The SnO2/ITO glass was employed as a pH sensor, fabricated by sputtering SnO2 thin films on the ITO glass. 3-Glycidyloxypropyltrimethoxysilane (GPTS) was utilized to immobilize uricase, catalase and the electron mediator (ferrocenecarboxylic acid, FcA) on the sensing window. The experimental results reveal that the optimal weight ratio of uricase, FcA to catalase (CAT) is 4:1:2. The sensor responds linearly between 2 mg/dl and 7 mg/dl at pH 7.5, in 20 mM of test solution, with a correlation coefficient of 0.99213. Accordingly, no significant interference was observed when interfering substances, glucose, urea and ascorbic acid, were added to the uric acid solution. Moreover, the recorded voltage was relatively constant during the first 28 days of measurement. Consequently, a potentiometric uric acid biosensor was realized with the advantages of low cost and simple fabrication. PMID:16830944

Liao, Cheng Wei; Chou, Jung Chuan; Sun, Tai Ping; Hsiung, Shen Kan; Hsieh, Jui Hsiang

2006-07-01

90

Successful management of uric acid nephrolithiasis with potassium citrate  

Microsoft Academic Search

Successful management of uric acid nephrolithiasis with potassium citrate. Eighteen patients with uric acid nephrolithiasis (six with uric acid stones alone and 12 with both uric acid and calcium stones) underwent long–term treatment (1 to 5.33 years, mean of 2.78 years) with potassium citrate (30 to 80 mEq\\/day, usually 60 mEq\\/day). Urinary pH increased from low (5.30 ± 0.31 SD)

Charles Y C Pak; Khashayar Sakhaee; Cindy Fuller

1986-01-01

91

Four hour creatinine clearance is better than plasma creatinine for monitoring renal function in critically ill patients  

PubMed Central

Introduction Acute kidney injury (AKI) diagnosis is based on an increase in plasma creatinine, which is a slowly changing surrogate of decreased glomerular filtration rate. We investigated whether serial creatinine clearance, a direct measure of the glomerular filtration rate, provided more timely and accurate information on renal function than serial plasma creatinine in critically ill patients. Methods Serial plasma creatinine and 4-hour creatinine clearance were measured 12-hourly for 24 hours and then daily in 484 patients. AKI was defined either as > 50% increase in plasma creatinine from baseline, or > 33.3% decrease in creatinine clearance. The diagnostic and predictive performance of the two AKI definitions were compared. Results Creatinine clearance decrease diagnosed AKI in 24% of those not diagnosed by plasma creatinine increase on entry. These patients entered the ICU sooner after insult than those diagnosed with AKI by plasma creatinine elevation (P = 0.0041). Mortality and dialysis requirement increased with the change in creatinine clearance-acute kidney injury severity class (P = 0.0021). Amongst patients with plasma creatinine < 1.24 mg/dl on entry, creatinine clearance improved the prediction of AKI considerably (Net Reclassification Improvement 83%, Integrated Discrimination Improvement 0.29). On-entry, creatinine clearance associated with AKI severity and duration (P < 0.0001) predicted dialysis need (area under the curve: 0.75) and death (0.61). A > 33.3% decrease in creatinine clearance over the first 12 hours was associated with a 2.0-fold increased relative risk of dialysis or death. Conclusions Repeated 4-hour creatinine clearance measurements in critically ill patients allow earlier detection of AKI, as well as progression and recovery compared to plasma creatinine. Trial Registration Australian New Zealand Clinical Trials Registry ACTRN012606000032550.

2012-01-01

92

Spectroscopic Estimation of Uric Acid and Its Derivatives.  

National Technical Information Service (NTIS)

Salts of uric acid with cobalt(II) and nickel(II) were prepared. Uric acid was used in the form of lithium urate. Cobalt(II) and nickel(II) were taken as their acetates. Maximum amount of uric acid dissolved in lithium carbonate was 0.1 gm. When lithium u...

T. Kausar

1989-01-01

93

Limitations of creatinine as a filtration marker in glomerulopathic patients  

Microsoft Academic Search

Limitations of creatinine as a filtration marker in glomerulopathic patients. To determine the reliability of creatinine as a measure of the glomerular filtration rate (GFR), we compared the simultaneous clearance of creatinine to that of three true filtration markers of graded size in 171 patients with various glomerular diseases. Using inulin (radius [rs] = 15 Å) as a reference marker,

Ovadia Shemesh; Helen Golbetz; Joseph P Kriss; Bryan D Myers

1985-01-01

94

A stable three-enzyme creatinine biosensor. 3. Immobilization of creatinine amidohydrolase and sensor development.  

PubMed

We describe the development of an extended use amperometric three-enzyme creatinine biosensor and the successful chemical modification and immobilization of the enzyme creatinine amidohydrolase using polyurethane prepolymers. Creatinine amidohydrolase is significantly stabilized by immobilization in polyurethane polymers. The half-life increases from six to more than 80 days in buffer at 37 degrees C. The effect of silver ions leached from amperometric reference electrodes on enzyme and sensor performance is discussed. The use of cellulose acetate cover membranes to prevent silver from reaching the enzyme is investigated. Sensors prepared with cover membranes have half-lives almost an order of magnitude greater than those prepared with no cover membrane over the silver electrode. The complete biosensor has been constructed on a clinical blood analyzer platform and is stable for many days. PMID:16701796

Berberich, Jason A; Chan, Andy; Boden, Mark; Russell, Alan J

2005-03-01

95

Amylase creatinine clearance ratio after biliary surgery.  

PubMed

The amylase creatinine clearance ratio (ACCR) is considered to be a more sensitive index of acute pancreatitis than the serum amylase level. Serial ACCR estimations were undertaken in 25 patients undergoing an elective cholecystectomy. Using accepted criteria, 28% of these patients developed, in the postoperative period, biochemical evidence of pancreatic gland damage, although the serum amylase level remained normal. This raised ACCR was particularly noted in patients who had undergone an exploration of the common bile duct. The ACCR would appear to be a more sensitive index of pancreatic gland disruption secondary to biliary surgery than the serum amylase level. PMID:402305

Donaldson, L A; McIntosh, W; Joffe, S N

1977-01-01

96

Urine alkalization facilitates uric acid excretion  

Microsoft Academic Search

BACKGROUND: Increase in the incidence of hyperuricemia associated with gout as well as hypertension, renal diseases and cardiovascular diseases has been a public health concern. We examined the possibility of facilitated excretion of uric acid by change in urine pH by managing food materials. METHODS: Within the framework of the Japanese government's health promotion program, we made recipes which consist

Aya Kanbara; Masayuki Hakoda; Issei Seyama

2010-01-01

97

Detection of Interstellar Urea  

NASA Astrophysics Data System (ADS)

Urea, a molecule discovered in human urine by H. M. Rouelle in 1773, has a significant role in prebiotic chemistry. Previous BIMA observations have suggested that interstellar urea [(NH2)2CO] is a compact hot core molecule such as other large molecules (e.g. methyl formate and acetic acid). We have conducted an extensive search for urea toward the high mass hot molecular core Sgr B2(N-LMH) using BIMA, CARMA and the IRAM 30 m. Because the spectral lines of heavy molecules like urea tend to be weak and hot cores display lines from a wide range of molecules, it is necessary to detect a number of urea lines and apply sophisticated statistical tests before having confidence in an identification. The 1 mm resolution of CARMA enables favorable coupling of the source size and synthesized beam size, which was found to be essential for the detection of weak signals. We have detected a total of 65 spectral lines (32 molecular transitions and 33 unidentified transitions), most of which are narrower than the SEST survey (Nummelin et al. 1998) due to the small synthesized beam (2.5" x 2") of CARMA. It significantly resolves out the contamination by extended emission and reveals the eight weak urea lines that were previously blended with nearby transitions. Our analysis indicates that these lines are likely to be urea since the resulting observed line frequencies are coincident with a set of overlapping connecting urea lines, and the observed line intensities are consistent with the expected line strengths of urea. In addition, we have developed a new statistical approach to examine the spatial correlation between the observed lines by applying the Student's t test to the high resolution channel maps obtained from CARMA. The t test shows consistent spatial distributions from all eight candidate lines, suggesting a common molecular origin, urea. Our t test method could have a broad impact on the next generation of arrays, such as ALMA, because the new arrays will require a method to systematically determine the credibility of detections of weaker signals from new and larger interstellar molecules.

Kuo, Hsin-Lun; Remijan, Anthony J.; Snyder, Lewis E.; Looney, Leslie W.; Friedel, Douglas N.; Lovas, Francis J.; McCall, Benjamin J.; Hollis, Jan M.

2010-11-01

98

Reverse iontophoresis of urea in health and chronic kidney disease: a potential diagnostic and monitoring tool?  

PubMed Central

Background Patients with chronic kidney disease (CKD) need regular monitoring, usually by blood urea and creatinine measurements, needing venepuncture, frequent attendances and a healthcare professional, with significant inconvenience. Noninvasive monitoring will potentially simplify and improve monitoring. We tested the potential of transdermal reverse iontophoresis of urea in patients with CKD and healthy controls. Methods Using a MIC 2® Iontophoresis Controller, reverse iontophoresis was applied on the forearm of five healthy subjects (controls) and 18 patients with CKD for 3–5 h. Urea extracted at the cathode was measured and compared with plasma urea. Results Reverse iontophoresis at 250 ?A was entirely safe for the duration. Cathodal buffer urea linearly correlated with plasma urea after 2 h (r = 0·82, P < 0·0001), to 3·5 h current application (r = 0·89, P = 0·007). The linear equations y = 0·24x + 1 and y = 0·21x + 4·63 predicted plasma urea (y) from cathodal urea after 2 and 3 h, respectively. Cathodal urea concentration in controls was significantly lower than in patients with CKD after a minimum current application of 2 h (P < 0·0001), with the separation between the two groups becoming more apparent with longer application (P = 0·003). A cathodal urea cut-off of 30 ?M gave a sensitivity of 83·3% and positive predictive value of 87% CKD. During haemodialysis, the fall in cathodal urea was able to track that of blood urea. Conclusion Reverse iontophoresis is safe, can potentially discriminate patients with CKD and healthy subjects and is able to track blood urea changes on dialysis. Further development of the technology for routine use can lead to an exciting opportunity for its use in diagnostics and monitoring.

Ebah, Leonard M; Read, Ian; Sayce, Andrew; Morgan, Jane; Chaloner, Christopher; Brenchley, Paul; Mitra, Sandip

2012-01-01

99

Luteolin prevents uric acid-induced pancreatic ?-cell dysfunction  

PubMed Central

Abstract Elevated uric acid causes direct injury to pancreatic ?-cells. In this study, we examined the effects of luteolin, an important antioxidant, on uric acid-induced ?-cell dysfunction. We first evaluated the effect of luteolin on nitric oxide (NO) formation in uric acid-stimulated Min6 cells using the Griess method. Next, we performed transient transfection and reporter assays to measure transcriptional activity of nuclear factor (NF)-?B. Western blotting assays were also performed to assess the effect of luteolin on the expression of MafA and inducible NO synthase (iNOS) in uric acid-treated cells. Finally, we evaluated the effect of luteolin on uric acid-induced inhibition of glucose-stimulated insulin secretion (GSIS) in Min6 cells and freshly isolated mouse pancreatic islets. We found that luteolin significantly inhibited uric acid-induced NO production, which was well correlated with reduced expression of iNOS mRNA and protein. Furthermore, decreased activity of NF-?B was implicated in inhibition by luteolin of increased iNOS expression induced by uric acid. Besides, luteolin significantly increased MafA expression in Min6 cells exposed to uric acid, which was reversed by overexpression of iNOS. Moreover, luteolin prevented uric acid-induced inhibition of GSIS in both Min6 cells and mouse islets. In conclusion, luteolin protects pancreatic ?-cells from uric acid-induced dysfunction and may confer benefit on the protection of pancreatic ?-cells in hyperuricemia-associated diabetes.

Ding, Ying; Shi, Xuhui; Shuai, Xuanyu; Xu, Yuemei; Liu, Yun; Liang, Xiubin; Wei, Dong; Su, Dongming

2014-01-01

100

21 CFR 862.1225 - Creatinine test system.  

Code of Federal Regulations, 2012 CFR

...ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1225 Creatinine test system. (a) Identification....

2012-04-01

101

Application of creatinine-sensitive biosensor for hemodialysis control.  

PubMed

The highly sensitive and selective potentiometric biosensor for creatinine determination has been developed by us earlier. In it, pH-sensitive field effect transistors were used as transducer and immobilized creatinine deiminase (EC 3.5.4.21)--as a biosensitive element. In the work presented, we optimized this biosensor for creatinine analysis in real samples of dialysate in patients with renal failure. The optimized version of biosensor was applied for on-line monitoring of the level of creatinine in the patient's dialysate fluid in the course of dialysis session. High correlation between the biosensor analysis and traditional Jaffe method was demonstrated. PMID:22459582

Zinchenko, O A; Marchenko, S V; Sergeyeva, T A; Kukla, A L; Pavlyuchenko, A S; Krasyuk, E K; Soldatkin, A P; El'skaya, A V

2012-05-15

102

Measurement of Serum Creatinine - Current Status and Future Goals  

PubMed Central

The first methods for the measurement of creatinine in serum and plasma were published over a century ago. Today, the Jaffe reaction using alkaline picrate remains the cornerstone of most current routine methods, after continuous refinements attempting to overcome inherent analytical interferences and limitations. With the recent introduction of the reporting of estimated glomerular filtration rate (eGFR), inter-laboratory agreement of serum creatinine results has become an important international priority. Expert professional bodies have recommended that all creatinine methods should become traceable to a reference method based on isotope dilution-mass spectrometry (IDMS). It is important that clinical biochemists have a good understanding of the relative performance of routine creatinine methods. Using a new commutable IDMS-traceable reference material (SRM 967), and a validated tandem IDMS assay developed in our laboratory, we assessed the accuracy of nine routine creatinine methods with assistance from other laboratories in our region. Three methods appeared to have patient sample bias that exceeded 5% in the range of creatinine concentrations where eGFR estimations are most important. Companies are currently recalibrating their creatinine assays. This task should be complete in 2007, and then creatinine results for eGFR calculations will require the use of a modified eGFR equation. Laboratories considering calibration changes before this time can seek advice from the Australasian Creatinine Working Group.

Peake, *Michael; Whiting, Malcolm

2006-01-01

103

Chemiresistor urea sensor  

DOEpatents

A sensor to detect and quantify urea in fluids resulting from hemodialysis procedures, and in blood and other body fluids. The sensor is based upon a chemiresistor, which consists of an interdigitated array of metal fingers between which a resistance measured. The interdigitated array is fabricated on a suitable substrate. The surface of the array of fingers is covered with a coating containing the enzyme urease which catalyzes the hydrolysis of urea to form the ammonium ion, the bicarbonate ion, and hydroxide-chemical products which provide the basis for the measured signal. In a typical application, the sensor could be used at bedside, in conjunction with an appropriate electronics/computer system, in order to determine the hemodialysis endpoint. Also, the chemiresistor used to detect urea, can be utilized with a reference chemiresistor which does not contain urease, and connected in a differential measurement arrangement, such that the reference chemiresistor would cancel out any fluctuations due to background effects.

Glass, Robert S. (Livermore, CA) [Livermore, CA

1997-01-01

104

Uric acid and chronic kidney disease: A time to act?  

PubMed

A role for uric acid in the pathogenesis and progression of renal disease had been proposed almost a century ago, but, too hastily dismissed in the early eighties. A body of evidence, mostly accumulated during the last decade, has led to a reappraisal of the influence of uric acid on hypertension, cardiovascular, and renal disease. The focus of this review will be solely on the relationship between serum uric acid and renal function and disease. We will review experimental evidence derived from animal and human studies, evidence gathered from a number of epidemiological studies, and from the few (up to now) studies of uric-acid-lowering therapy. Some space will be also devoted to the effects of uric acid in special populations, such as diabetics and recipients of kidney allografts. Finally we will briefly discuss the challenges of a trial of uric-acid-lowering treatment, and the recent suggestions on how to conduct such a trial. PMID:24175261

Bellomo, Gianni

2013-05-01

105

Uric acid and chronic kidney disease: A time to act?  

PubMed Central

A role for uric acid in the pathogenesis and progression of renal disease had been proposed almost a century ago, but, too hastily dismissed in the early eighties. A body of evidence, mostly accumulated during the last decade, has led to a reappraisal of the influence of uric acid on hypertension, cardiovascular, and renal disease. The focus of this review will be solely on the relationship between serum uric acid and renal function and disease. We will review experimental evidence derived from animal and human studies, evidence gathered from a number of epidemiological studies, and from the few (up to now) studies of uric-acid-lowering therapy. Some space will be also devoted to the effects of uric acid in special populations, such as diabetics and recipients of kidney allografts. Finally we will briefly discuss the challenges of a trial of uric-acid-lowering treatment, and the recent suggestions on how to conduct such a trial.

Bellomo, Gianni

2013-01-01

106

Serum Uric Acid, Cholesterol and Cortisol Intercorrelations-in-Normoactive Subjects.  

National Technical Information Service (NTIS)

Repeat determinations of serum uric acid, cholesterol, and cortisol were done thrice daily for one week on 8 healthy Navy corpsmen during their routine duties on an aircraft carrier. The intraindividual correlations between uric acid and cholesterol, uric...

R. T. Rubin B. R. Clark R. E. Poland R. J. Arthur

1971-01-01

107

Creatinine metabolism by Clostridium welchii isolated from human faeces  

Microsoft Academic Search

Summary AClostridium welchii has been isolated from human faeces which can deaminate creatinine to N-methyl hydantoin. Evidence suggests the reaction is inducible since the rate of conversion is increased by growth of the organism in creatinine-rich media.

E. ten Krooden; C. W. I. Owens

1975-01-01

108

Amylase creatinine clearance ratio following biliary tract surgery  

Microsoft Academic Search

An increase in the amylase creatinine clearance ratio (ACCR) is considered to be a more specific diagnostic test of acute pancreatitis than elevation of the serum or urine amylase activity. Simultaneous serum and urine samples for the determination of amylase and creatinine were obtained preoperatively and at various intervals postoperatively in 75 patients undergoing surgery. No increase in ACCR was

Francesco Tonelli; Emidio Senati; Marileda Indinnimeo

1981-01-01

109

Increasing the sensitivity of the Jaffe reaction for creatinine  

NASA Technical Reports Server (NTRS)

Study of analytical procedure has revealed that linearity of creatinine calibration curve can be extended by using 0.03 molar picric acid solution made up in 70 percent ethanol instead of water. Three to five times more creatinine concentration can be encompassed within linear portion of calibration curve.

Tom, H. Y.

1973-01-01

110

Immobilization of uricase enzyme on self-assembled gold nanoparticles for application in uric acid biosensor.  

PubMed

An enzyme immobilization matrix is described by preparing a self-assembly of gold nanoparticles (GNPs) over a self-assembled monolayer (SAM) of 3-aminopropyltriethoxysilane (APTES) on an indium-tin-oxide (ITO) coated glass plate. The surface of the GNPs was modified with a mixed (1:9) SAM of 11-mercaptoundecanoic acid (MUA) and 3-mercapto-propionic acid (MPA). The enzyme, uricase was covalently immobilized to the carboxyl groups of the mixed SAM of MUA/MPA through carbodiimide coupling reaction. The whole assembly was constructed on 1 cm2 area of ITO-glass plate and was tested as an amperometric biosensor for the detection of uric acid in aqueous solution. The biosensor assembly was characterized by atomic force microscopy (AFM) and electrochemical techniques. The AFM of the enzyme biosensor assembly reveals an asymmetrical sharp regular island-like structure with an average roughness parameter value of 2.81 nm. Chronoamperometric response was measured as a function of uric acid concentration in aqueous solution (pH 7.4), which exhibits a linear response over a concentration range of 0.07 to 0.63 mM with a sensitivity of 19.27 microAmM(-1) and a response of 25 s with excellent reproducibility. These results are not influenced by the presence of interfering reagents such as ascorbic acid, urea and glucose. GNPs-biomolecule assemblies constructed using this method may facilitate development of new hybrid biosensing materials. PMID:21770094

Ahuja, T; Tanwar, V K; Mishra, S K; Kumar, D; Biradar, A M; Rajesh

2011-06-01

111

Clinical and biochemical aspects of uric acid overproduction  

Microsoft Academic Search

Purine nucleotides are synthesized and degraded through a regulated series of reactions which end in the formation of uric acid. Increased uric acid synthesis may be the result of two major pathophysiological disorders: increasedde novo purine synthesis and enhanced purine nucleotide degradation, both of which may be the result of an increased or decreased enzyme activity. In addition, some conditions

J. García Puig; F. Antón Mateos

1994-01-01

112

Fluorometric Method for Determination of Uric Acid in Flour.  

National Technical Information Service (NTIS)

A fluorescence technique is described for the determination of uric acid content in flour and its use as an index of insect infestation. Uric acid, a major component of the excreta of adult Tribolium used in this study for natural infestation, accumulates...

L. G. Holmes L. W. Smith

1980-01-01

113

Serum Uric Acid Levels and Leadership in the Marine Corps.  

National Technical Information Service (NTIS)

Serum uric acid levels were determined in men graduating from O.C.S., men dropped from O.C.S., enlisted men with good records and enlisted men who were serving sentences in the brig. There were no significant differences in the mean serum uric acid levels...

P. J. Rasch J. S. Bird J. W. Hamby H. J. Burns

1968-01-01

114

Urinary creatinine to serum creatinine ratio and renal failure index in dogs infected with Babesia canis.  

PubMed

Urinary creatinine to serum creatinine (UCr/SCr) ratio and renal failure index (RFI) are useful indices of renal damage. Both UCr/SCr ratio and RFI are used in differentiation between prerenal azotaemia and acute tubular necrosis. In this work the authors calculated the UCr/SCr ratio and RFI in dogs infected with Babesia canis and the values of these indices in azotaemic dogs infected with the parasite. The results of this study showed significantly lower UCr/SCr ratio in dogs infected with B. canis than in healthy dogs. Moreover, in azotaemic dogs infected with B. canis the UCr/SCr ratio was significantly lower and the RFI was significantly higher than in non-azotaemic dogs infected with B. canis. The calculated correlation between RFI and duration of the disease before diagnosis and treatment was high, positive and statistically significant (r = 0.89, p < 0.001). The results of this study showed that during the course of canine babesiosis caused by B. canis in Poland acute tubular necrosis may develop. PMID:23990425

Zygner, Wojciech; Gójska-Zygner, Olga; Weso?owska, Agnieszka; W?drychowicz, Halina

2013-09-01

115

Validation of high-throughput methods for measuring blood urea nitrogen and urinary albumin concentrations in mice  

Microsoft Academic Search

Chronic kidney disease is a substantial medical and economic burden. Animal models, including mice, are a crucial component of kidney disease research; however, recent studies disprove the ability of autoanalyzer methods to accurately quantify plasma creatinine levels, an established marker of kidney disease, in mice. Therefore, we validated autoanalyzer methods for measuring blood urea nitrogen (BUN) and urinary albumin concentrations,

S Grindle; C Garganta; S Sheehan; J Gile; A Lapierre; H Whitmore; B Paigen; K DiPetrillo

2006-01-01

116

Effect of urea and uric acid on influenza virus type C  

Microsoft Academic Search

Summary The replication of influenza type C\\/1233 virus following inoculation into the amniotic sac of embryonated hen's eggs is significantly greater than that seen in the allantoic cavity. However, optimal growth condition for amniotically propagated C\\/1233 occur in the allantois of 8-day old embryos incubated post-inoculation at 32° C. Differences in pH levels between the amniotic and allantoic cavities did

A. K. Prasad; J. W. Czekalowski; R. Jennings

1984-01-01

117

Quinine and Urea  

NSDL National Science Digital Library

The WebWare molecules of the month are discussed in two laboratory articles in this issue. Quinine is studied in the article "A Fluorimetric Approach to Studying the Effects of Ionic Strength on Reaction Rates: An Undergraduate Steady-State Fluorescence Laboratory Experiment" by Stephen W. Bigger, Peter J. Watkins, and Bruce Verity. Urea, a typical protein denaturant, is used as a cosolvent in the article "Transfer Free Energy and the Hydrophobic Effect" by Joseph M. Serafin.

118

Chemiresistor urea sensor  

DOEpatents

A sensor is disclosed to detect and quantify urea in fluids resulting from hemodialysis procedures, and in blood and other body fluids. The sensor is based upon a chemiresistor, which consists of an interdigitated array of metal fingers between which a resistance measured. The interdigitated array is fabricated on a suitable substrate. The surface of the array of fingers is covered with a coating containing the enzyme urease which catalyzes the hydrolysis of urea to form the ammonium ion, the bicarbonate ion, and hydroxide-chemical products which provide the basis for the measured signal. In a typical application, the sensor could be used at bedside, in conjunction with an appropriate electronics/computer system, in order to determine the hemodialysis endpoint. Also, the chemiresistor used to detect urea, can be utilized with a reference chemiresistor which does not contain urease, and connected in a differential measurement arrangement, such that the reference chemiresistor would cancel out any fluctuations due to background effects. 16 figs.

Glass, R.S.

1997-12-16

119

Urine Test: Microalbumin-to-Creatinine Ratio (For Parents)  

MedlinePLUS

... in the urine called cretonne. The body normally filters out creatinine in the urine at a steady ... to obtain the urine specimen. A urine collection bag with adhesive tape on one end might instead ...

120

Quantitative analysis of creatinine in urine by metalized nanostructured parylene  

NASA Astrophysics Data System (ADS)

A highly accurate, real-time multisensor agent monitor for biomarker detection is required for early detection of kidney diseases. Urine creatinine level can provide useful information on the status of the kidney. We prepare nanostructured surface-enhanced Raman spectroscopy (SERS) substrates without template or lithography, which provides controllable, well-organized nanostructures on the surface, for the quantitative analysis of creatinine concentration in urine. We present our work on sensitivity of the SERS substrate to urine samples collected from diabetic patients and healthy persons. We report the preparation of a new type of SERS substrate, which provides fast (<10 s), highly sensitive (creatinine concentration <0.5 ?g/mL) and reproducible (<5% variation) detection of urine. Our method to analyze the creatinine level in urine is in good agreement with the enzymatic method.

Wang, Hui; Malvadkar, Niranjan; Koytek, S.; Bylander, J.; Reeves, W. Brian; Demirel, Melik C.

2010-03-01

121

Correlations between renal interstitium and level of serum creatinine  

Microsoft Academic Search

Morphometric investigations in 40 patients suffering from perimembranous glomerulonephritis at different stages showed that there is no certain relationship between the severity of glomerular lesions and the serum creatinine level. In 19 cases in stages I–III, with serum creatinine level less than 1.2 mg\\/100 ml on biopsy, the renal interstitium was less enlarged than in 21 cases in the same

A. Bohle; K. E. Grund; S. Mackensen; M. Tolon

1977-01-01

122

Renal Excretion of Uric Acid. Alterations during Stressful Underwater Demolition Team Training.  

National Technical Information Service (NTIS)

Serum uric acid and 24-hour uric acid excretion were determined in 16 men during various phases of U.S. Navy Underwater Demolition Team training activities. Elevations of serum uric acid were associated with decreases in uric acid clearance and decreases ...

L. M. Zir W. B. McHugh R. H. Rahe R. J. Arthur R. T. Rubin

1973-01-01

123

Prolonged winter undernutrition and the interpretation of urinary allantoin: creatinine ratios in ungulates  

USGS Publications Warehouse

The urinary allantoin:creatinine (A:C) ratio (expressed in micromoles of allantoin to micromoles of creatinine) has shown potential as an index of recent winter energy intake in preliminary controlled studies of elk (Cervus elaphus) involving mild condition deterioration (up to 11% loss of body mass). To ensure reliable nutritional assessments of free-ranging cervids by measuring A:C ratios of urine in snow, it is essential to extend this work. We assessed the effect of moderate and severe winter nutritional restriction on urinary A:C ratios of captive white-tailed deer (Odocoileus virginianus) that lost up to 32% body mass and related these ratios to metabolizable energy intake (MEI), body-mass loss, and other reported nutritional indicators. Deer in the control group were fed a low-protein, low-energy diet ad libitum, whereas deer in the treatment group were fed restricted amounts of the same diet. MEI was below the winter maintenance requirement for all deer, but was lower (P = 0.029) in treatment deer than in control deer. Percent body-mass loss differed between the two groups as the study progressed, and represented the full range of physiological tolerance (0-32% loss). Mean A:C ratios of control deer, which lost up to 17.4% body mass, showed a slight increasing (P = 0.086) trend, whereas initially similar A:C ratios of severely restricted deer increased (P = 0.0002) markedly by the eighth week (0.52 vs. 0.09 |mol:|mol). The urinary A:C ratio was not related (P = 0.839) to recent (2 days prior to urine sampling) MEI, but there was a marginally significant relation (r2 = 0.42, P = 0.110) between the A:C ratio and cumulative percent mass loss. The urinary A:C ratio was directly related to urinary urea nitrogen: creatinine (r2 = 0.59, P < 0.0001) and 3-methylhistidine:creatinine (r2 = 0.43, P < 0.0001) ratios. This study confirms that elevated and increasing A:C ratios may be due either to increasing energy intake or to accelerated tissue catabolism and increased endogenous contributions to urinary allantoin excretion.

DelGiudice G. G.; Kerr, K. D.; Mech, L. D.; Seal, U. S.

2000-01-01

124

Low serum urea level in dehydrated patients with central diabetes insipidus.  

PubMed Central

Dehydrated patients usually present with an elevated serum urea level, owing in part to increased renal reabsorption of urea mediated by antidiuretic hormone (ADH). We carried out a study to examine whether, during dehydration, the variations in the serum urea level could discriminate patients with central diabetes insipidus (CDI) from those with dehydration not due to CDI. We studied retrospectively 27 episodes of dehydration in 23 patients with CDI and 14 episodes in 14 patients without CDI. The mean serum urea level was 2.9 mmol/L in the CDI group and 15.4 mmol/L in the patients without CDI (p less than 0.001); the mean serum sodium level was 155 mmol/L in both groups. All the patients with CDI had a sodium/urea ratio greater than 24.2, whereas the ratio was less than 21.7 in all the patients without CDI. In the patients with CDI a positive correlation was found between the magnitude of diuresis and the percentage decrease in the serum urea level compared with the level before dehydration (p less than 0.001). In the patients with CDI the serum urea level returned to the level before dehydration after the administration of vasopressin; a striking increase in the clearance of urea, which exceeded the creatinine clearance, was observed during dehydration in the three patients in whom clearance studies were done. The results suggest that serum urea values can be used to distinguish patients dehydrated because of CDI from those with hypertonic dehydration but without ADH deficiency and that during dehydration the net reabsorption of urea is dependent on the renal action of ADH.

Comtois, R; Bertrand, S; Beauregard, H; Vinay, P

1988-01-01

125

Serum uric acid and metabolic syndrome in Taiwanese adults.  

PubMed

A positive association between serum uric acid and metabolic syndrome has been reported, but little information is available about the association between serum uric acid and metabolic syndrome in Taiwanese adults. The purpose of this study was to investigate the association between serum uric acid levels and metabolic syndrome in Taiwanese adults. We performed a cross-sectional study of 2085 men and 1557 women. All of the participants underwent a health screening during the period from January 2005 to December 2005 at a health center of the Shin Kong Wu Ho-Su Memorial Hospital. Metabolic syndrome was defined according to the National Cholesterol Education Program Adult Treatment Panel III criteria. The results showed that hyperuricemia was significantly associated with increased risk for hypertriglyceridemia, low high-density lipoprotein cholesterol level, and high blood pressure in men and women. The risk of metabolic syndrome was significantly higher in the fourth quartile than in the first quartile of uric acid level in men (odds ratio [OR], 1.50; 95% confidence interval [CI], 1.06-2.14) and women (OR, 2.33; 95% CI, 1.39-3.93). In addition, uric acid level was inversely associated with hyperglycemia in men. The ORs of hyperglycemia for the second, third, and fourth quartile of uric acid were 0.69 (95% CI, 0.46-1.03), 0.55 (95% CI, 0.37-0.83), and 0.45 (95% CI, 0.29-0.69), respectively, compared with the lowest quartile of uric acid. The results demonstrate that there is a positive association between serum uric acid levels and metabolic syndrome and an inverse association between uric acid and fasting plasma glucose in Taiwanese adults. PMID:20005536

Liu, Pei-Wen; Chang, Tsui-Yen; Chen, Jong-Dar

2010-06-01

126

The relationship between the regional abdominal adipose tissue distribution and the serum uric acid levels in people with type 2 diabetes mellitus  

PubMed Central

Background Hyperuricemia is associated with obesity. The visceral adiposity and subcutaneous adiposity may be associated with the differential metabolic risk, and the distribution of abdominal adipose tissue was significantly altered in people with type 2 diabetes mellitus (DM) compared to healthy people. Our study was performed to determine to the association between the regional abdominal adipose tissue distribution and serum uric acid levels in people with type 2 DM. Methods A total of 699 people with type 2 DM and who had undergone abdominal computed tomography assessment of the visceral fat area and subcutaneous fat area were included. The serum uric acid levels were measured by the uricase method. Hyperuricemia was defined by cut-off value of > 7 mg/dl for men and > 6 mg/dl for women. Results The visceral fat area was positively associated with the serum uric acid levels after adjustment for age, sex, systolic blood pressure, diastolic blood pressure, serum creatinine, hemoglobin, serum albumin, serum high-density lipoprotein, serum triglyceride and hemoglobin A1c (?-coefficient = 0.117, p < 0.001). The logistic regression analysis showed that the visceral fat area was the significant independent predictor of hyperuricemia (OR 2.33, 95% CI, 1.21-4.50, p = 0.012). But there was no significant association between the subcutaneous fat area and the serum uric acid levels (?-coefficient = 0.061, p = 0.255). Conclusions our data shows that the visceral fat area was positively associated with the serum uric acid levels, but the subcutaneous fat area was not in people with type 2 DM.

2012-01-01

127

Uric acid is a risk factor for ischemic stroke and all-cause mortality in the general population: a gender specific analysis from The Troms? Study  

PubMed Central

Background The role of serum uric acid as an independent predictor of cardiovascular disease and death is uncertain in the general population. Adjustments for additional cardiovascular risk factors have not been consistent. We examined the association of serum uric acid with all-cause mortality, ischemic stroke and myocardial infarction in a prospective population based study, with several traditional and non-traditional risk factors for cardiovascular disease included in the model. Methods A population-based prospective cohort study was performed among 2696 men and 3004 women. Endpoints were all-cause mortality after 15 years, and fatal or non-fatal myocardial infarction (MI) and ischemic stroke after 12 years. Results 1433 deaths, 659 MIs and 430 ischemic strokes occurred during follow-up. Fully adjusted Cox regression analyses showed that per 1 SD (87 ?mol/L) increase in serum uric acid level, the risk of all-cause mortality increased in both genders (hazard ratios, HR men; 1.11, 95% CI 1.02-1.20, women; 1.16, 1.05-1.29). HRs and 95% CI for stroke were 1.31, 1.14-1.50 in men, 1.13, 0.94-1.36 in women, and 1.22 (1.09, 1.35) in the overall population. No independent associations were observed with MI. Conclusion Serum uric acid was associated with all-cause mortality in men and women, even after adjustment for blood pressure, estimated GFR, urinary albumin/creatinine ratio, drug intake and traditional cardiovascular risk factors. After the same adjustments, serum uric acid was associated with 31% increased risk of stroke in men.

2013-01-01

128

The metabolic syndrome and uric acid nephrolithiasis: Novel features of renal manifestation of insulin resistance  

Microsoft Academic Search

The metabolic syndrome and uric acid nephrolithiasis: Novel features of renal manifestation of insulin resistance.BackgroundUric acid nephrolithiasis primarily results from low urinary pH, which increases the concentration of the insoluble undissociated uric acid, causing formation of both uric acid and mixed uric acid\\/calcium oxalate stones. These patients have recently been described as exhibiting features of insulin resistance. This study was

NICOLA ABATE; MANISHA CHANDALIA; Alberto V. Cabo-Chan; Orson W. Moe; KHASHAYAR SAKHAEE

2004-01-01

129

Dicarboxylic Acid-Urea Complexes.  

National Technical Information Service (NTIS)

A study of the reaction of several acids with urea resulted in a series of compounds of varying stoichiometry and structure. The acids having the structure HO2C(CH2)nCO2H produced saltlike compounds with urea when n = 0 and 1 and H-bonded complexes for n ...

J. Radell B. W. Brodman J. J. Domanski

1966-01-01

130

21 CFR 862.1775 - Uric acid test system.  

Code of Federal Regulations, 2012 CFR

...ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1775 Uric acid test system. (a) Identification....

2012-04-01

131

SERS quantitative urine creatinine measurement of human subject  

NASA Astrophysics Data System (ADS)

SERS method for biomolecular analysis has several potentials and advantages over traditional biochemical approaches, including less specimen contact, non-destructive to specimen, and multiple components analysis. Urine is an easily available body fluid for monitoring the metabolites and renal function of human body. We developed surface-enhanced Raman scattering (SERS) technique using 50nm size gold colloidal particles for quantitative human urine creatinine measurements. This paper shows that SERS shifts of creatinine (104mg/dl) in artificial urine is from 1400cm-1 to 1500cm-1 which was analyzed for quantitative creatinine measurement. Ten human urine samples were obtained from ten healthy persons and analyzed by the SERS technique. Partial least square cross-validation (PLSCV) method was utilized to obtain the estimated creatinine concentration in clinically relevant (55.9mg/dl to 208mg/dl) concentration range. The root-mean square error of cross validation (RMSECV) is 26.1mg/dl. This research demonstrates the feasibility of using SERS for human subject urine creatinine detection, and establishes the SERS platform technique for bodily fluids measurement.

Wang, Tsuei Lian; Chiang, Hui-hua K.; Lu, Hui-hsin; Hung, Yung-da

2005-03-01

132

Two novel creatinine adducts of andrographolide in human urine.  

PubMed

Andrographolide is a major labdane diterpenoid of the traditional Chinese and Ayurvedic medicine. Andrographis paniculate (Burm) Nees, is used in clinical situations in China mainly to treat fever, cold, and inflammation. In our previous study, fifteen metabolites of andrographolide were identified in human urine. However, there are still two other unknown metabolites. The aim of this study was to elucidate the structures of these two metabolites. 3. The two metabolites which are probably epimers were identified as creatinine adducts, and their structures were determined to be 14-deoxy-12-(creatinine-5-yl)-andrographolide-19-O-?-D-glucuronide A (Metabolite 1) and 14-deoxy-12-(creatinine-5-yl)-andrographolide-19-O-?-D-glucuronide B (Metabolite 2) by means of spectroscopic evidences. 4. It is for the first time that the formation of creatinine adducts as a novel metabolic pathway is reported. The mechanism was presumed that ?-carbon (C-12) of ?, ?-unsaturated carbonyl was attacked by a 5-anion intermediate of creatinine formed through elimination of a proton, followed by the double bond migration from 12(13) to 13(14) and elimination of the hydroxyl group at C-14. PMID:22568631

Qiu, Feng; Cui, Liang; Chen, Lixia; Sun, Jiawen; Yao, Xinsheng

2012-09-01

133

Uric Acid and Incident Kidney Disease in the Community  

Microsoft Academic Search

Uric acid may mediate aspects of the relationship between hypertension and kidney disease via renal vasoconstriction and systemic hypertension. To investigate the relationship between uric acid and subsequent reduced kidney function, limited-access data of 13,338 participants with intact kidney function in two community-based cohorts, the Atherosclerosis Risks in Communities and the Cardiovas- cular Health Study, were pooled. Mean baseline serum

Daniel E. Weiner; Hocine Tighiouart; Essam F. Elsayed; John L. Griffith; Deeb N. Salem; Andrew S. Levey

2008-01-01

134

Non-enzymatic cyclization of creatine ethyl ester to creatinine.  

PubMed

Creatine ethyl ester was incubated at 37 degrees C in both water and phosphate-buffered saline and the diagnostic methylene resonances in the (1)H NMR spectrum were used to identify the resultant products. It was found that mild aqueous conditions result in the cyclization of creatine ethyl ester to provide inactive creatinine as the exclusive product, and this transformation becomes nearly instantaneous as the pH approaches 7.4. This study demonstrates that mild non-enzymatic conditions are sufficient for the cyclization of creatine ethyl ester into creatinine, and together with previous results obtained under enzymatic conditions suggests that there are no physiological conditions that would result in the production of creatine. It is concluded that creatine ethyl ester is a pronutrient for creatinine rather than creatine under all physiological conditions encountered during transit through the various tissues, thus no ergogenic effect is to be expected from supplementation. PMID:19660433

Giese, Matthew W; Lecher, Carl S

2009-10-16

135

Creatinine, Diet, Micronutrients, and Arsenic Methylation in West Bengal, India  

PubMed Central

Background: Ingested inorganic arsenic (InAs) is methylated to monomethylated (MMA) and dimethylated metabolites (DMA). Methylation may have an important role in arsenic toxicity, because the monomethylated trivalent metabolite [MMA(III)] is highly toxic. Objectives: We assessed the relationship of creatinine and nutrition—using dietary intake and blood concentrations of micronutrients—with arsenic metabolism, as reflected in the proportions of InAS, MMA, and DMA in urine, in the first study that incorporated both dietary and micronutrient data. Methods: We studied methylation patterns and nutritional factors in 405 persons who were selected from a cross-sectional survey of 7,638 people in an arsenic-exposed population in West Bengal, India. We assessed associations of urine creatinine and nutritional factors (19 dietary intake variables and 16 blood micronutrients) with arsenic metabolites in urine. Results: Urinary creatinine had the strongest relationship with overall arsenic methylation to DMA. Those with the highest urinary creatinine concentrations had 7.2% more arsenic as DMA compared with those with low creatinine (p < 0.001). Animal fat intake had the strongest relationship with MMA% (highest tertile animal fat intake had 2.3% more arsenic as MMA, p < 0.001). Low serum selenium and low folate were also associated with increased MMA%. Conclusions: Urine creatinine concentration was the strongest biological marker of arsenic methylation efficiency, and therefore should not be used to adjust for urine concentration in arsenic studies. The new finding that animal fat intake has a positive relationship with MMA% warrants further assessment in other studies. Increased MMA% was also associated, to a lesser extent, with low serum selenium and folate.

Basu, Arin; Mitra, Soma; Chung, Joyce; Guha Mazumder, D.N.; Ghosh, Nilima; Kalman, David; von Ehrenstein, Ondine S.; Steinmaus, Craig; Liaw, Jane

2011-01-01

136

Serum Uric Acid and Non-Alcoholic Fatty Liver Disease in Non-Diabetic Chinese Men  

PubMed Central

Increased serum uric acid (SUA) levels may be involved in the development of non-alcoholic fatty liver disease (NAFLD) in men presenting with metabolic syndrome (MetS) and/or insulin resistance. We aimed to determine the independent relationship between SUA and NAFLD in non-diabetic Chinese male population, and to explore the determinants of SUA levels among indexes of adiposity, lipid, and genotypes pertaining to triglycerides metabolism, inflammation, oxidative stress, and SUA concentrations. A total of 1440 men, classified depending on the presence of ultrasonographically detected NAFLD, underwent a complete healthy checkup program. Genotypes were extracted from our previously established genome-wide association study database. After adjusting for age, smoking, drinking, body mass index, homeostasis model assessment of insulin resistance, C-reactive protein, creatinine, alanine aminotransferase (ALT) and components of metabolic syndrome, the odds ratio for NAFLD, comparing the highest with the lowest SUA quartile, was 2.81 (95% confidence interval 1.66–4.76). A stepwise multivariate linear regression analysis (R2?=?0.238, P<0.001) retained age, waist circumference, serum creatinine, triglycerides, the Q141K variant in ABCG2 (rs2231142) and NAFLD as significant predictors of SUA levels (all P<0.001). Besides, ALT and Met196Arg variant in TNFRSF1B (rs1061622) additionally associated with SUA among individuls with NAFLD. Our data suggest that in Chinese men, elevated SUA is significantly associated with NAFLD, independent of insulin resistance and other metabolic disorders, such as central obesity or hypertriglyceridemia. Meanwhile, among subjects with NAFLD, index of liver damage, such as elevated ALT combined with genetic susceptibility to inflammation associated with increased SUA levels.

Tan, Aihua; Gao, Yong; Liang, Zhengjia; Shi, Deyi; Huang, Zhang; Zhang, Haiying; Yang, Xiaobo; Lu, Zheng; Wu, Chunlei; Liao, Ming; Sun, Yu; Qin, Xue; Hu, Yanling; Li, Li; Peng, Tao; Li, Zhixian; Yang, Xiaoli; Mo, Zengnan

2013-01-01

137

Interaction between dietary content of protein and sodium chloride on milk urea concentration, urinary urea excretion, renal recycling of urea, and urea transfer to the gastrointestinal tract in dairy cows.  

PubMed

Dietary protein and salt affect the concentration of milk urea nitrogen (MUN; mg of N/dL) and the relationship between MUN and excretion of urea nitrogen in urine (UUN; g of N/d) of dairy cattle. The aim of the present study was to examine the effects of dietary protein and sodium chloride (NaCl) intake separately, and their interaction, on MUN and UUN, on the relationship between UUN and MUN, on renal recycling of urea, and on urea transfer to the gastrointestinal tract. Twelve second-parity cows (body weight of 645±37 kg, 146±29 d in milk, and a milk production of 34.0±3.28 kg/d), of which 8 were previously fitted with a rumen cannula, were fitted with catheters in the urine bladder and jugular vein. The experiment had a split-plot arrangement with dietary crude protein (CP) content as the main plot factor [116 and 154 g of CP/kg of dry matter (DM)] and dietary NaCl content as the subplot factor (3.1 and 13.5 g of Na/kg of DM). Cows were fed at 95% of the average ad libitum feed intake of cows receiving the low protein diets. Average MUN and UUN were, respectively, 3.90 mg of N/dL and 45 g of N/d higher for the high protein diets compared with the low protein diets. Compared with the low NaCl diets, MUN was, on average, 1.74 mg of N/dL lower for the high NaCl diets, whereas UUN was unaffected. We found no interaction between dietary content of protein and NaCl on performance characteristics or on MUN, UUN, urine production, and renal clearance characteristics. The creatinine clearance rate was not affected by dietary content of protein and NaCl. Urea transfer to the gastrointestinal tract, expressed as a fraction of plasma urea entry rate, was negatively related to dietary protein, whereas it was not affected by dietary NaCl content. We found no interaction between dietary protein and NaCl content on plasma urea entry rate and gastrointestinal urea entry rate or their ratio. The relationship between MUN and UUN was significantly affected by the class variable dietary NaCl content: UUN=-17.7±7.24 + 10.09±1.016 × MUN + 2.26±0.729 × MUN (for high NaCl); R(2)=0.85. Removal of the MUN × NaCl interaction term lowered the coefficient of determination from 0.85 to 0.77. In conclusion, dietary protein content is positively related to MUN and UUN, whereas dietary NaCl content is negatively correlated to MUN but NaCl content is not related to UUN. We found no interaction between dietary protein and NaCl content on performance, MUN, UUN, or renal urea recycling, nor on plasma urea entry rate and urea transfer to the gastrointestinal tract. For a proper interpretation of the relationship between MUN and UUN, the effect of dietary NaCl should be taken into account, but we found no evidence that the effect of dietary NaCl on MUN is dependent on dietary protein content. PMID:23871366

Spek, J W; Bannink, A; Gort, G; Hendriks, W H; Dijkstra, J

2013-09-01

138

Urinary kidney injury biomarkers and urine creatinine normalization: a false premise or not?  

PubMed

Substantial research has focused on the discovery of urinary biomarkers to detect acute kidney injury (AKI) before a rise in serum creatinine. As in chronic kidney diseases, the concentrations of urinary AKI biomarkers have been normalized to urine creatinine concentration to account for creatinine clearance and urine flow. Waikar et al. challenge the assumption that normalization to creatinine clearance in a chronic disease state can be extrapolated to an acute state, in which creatinine clearance is, by definition, changing acutely. PMID:20706215

Goldstein, Stuart L

2010-09-01

139

Low temperature Raman and DFT study of creatinine  

NASA Astrophysics Data System (ADS)

The Raman spectra of creatinine powder in the wavenumber region of 500-3500 cm-1 have been recorded as a function of temperature ranging from 293 K to 83 K and different clusters of creatinine were optimized with DFT method to determine hydrogen bonding network in crystalline creatinine. The accurate vibrational assignment of all vibrational bands of creatinine has been done on the basis of the calculated vibrational spectra and the potential energy distribution. The calculated Raman spectra of hydrogen bonded tetramer cluster matches nicely with the experimentally observed spectra confirming four molecules in unit cell as reported by crystallographic data. In addition signature of dimer, which is just half of the tetramer, has also been observed. The bands associated with sbnd CH3, sbnd CH2, ?(Cdbnd O), ?(Cdbnd N) and ?(Csbnd H) have been given more focus to see the behavior of hydrogen bond network with temperature. The analysis of these bands reveals that a gradual change (increase/decrease) in linewidth and peak position occurs with temperature as a consequence of the anharmonic coupling of internal modes with phonon mode and intermolecular interaction. The behavior of hydrogen bond network on cooling has been explained in terms of contraction of unit cell.

Vikram, K.; Mishra, Shivangi; Srivastava, S. K.; Singh, Ranjan K.

2012-03-01

140

Urine Creatinine Excretion: Variability and Volume Dependency during Sleep Deprivation.  

National Technical Information Service (NTIS)

Continuous 6-hour urine samples were collected from 4 healthy young adult men during 4 control days and 9 days of sleep deprivation. Considerable variation in creatinine levels was present in the samples from all 4 subjects, and there was a significant di...

R. T. Rubin

1971-01-01

141

Elevated blood urea, independent of glomerular filtration rate (GFR), confers increased risk of adverse functional outcome in elderly hip fracture patients  

Microsoft Academic Search

This retrospective cohort study investigated the possible interrelations of GFR and functional outcome in elderly hip fracture patients. The final analyses comprised 499 consecutive patients undergoing standard medical, surgical and rehabilitation treatment in an orthogeriatric unit of a tertiary care hospital. Functional outcomes were assessed by Functional Independence Measurement (FIM™) scores. Kidney function was assessed by blood urea and creatinine,

Abraham Adunsky; Eliyahu H. Mizrahi; Alexander Kaplan; Elena Purits; Anna Waitzman; Marina Arad

2011-01-01

142

A general photonic crystal sensing motif: creatinine in bodily fluids.  

PubMed

We developed a new sensing motif for the detection and quantification of creatinine, which is an important small molecule marker of renal dysfunction. This novel sensor motif is based on our intelligent polymerized crystalline colloidal array (IPCCA) materials, in which a three-dimensional crystalline colloidal array (CCA) of monodisperse, highly charged polystyrene latex particles are polymerized within lightly cross-linked polyacrylamide hydrogels. These composite hydrogels are photonic crystals in which the embedded CCA diffracts visible light and appears intensely colored. Volume phase transitions of the hydrogel cause changes in the CCA lattice spacings which change the diffracted wavelength of light. We functionalized the hydrogel with two coupled recognition modules, a creatinine deiminase (CD) enzyme and a 2-nitrophenol (2NPh) titrating group. Creatinine within the gel is rapidly hydrolyzed by the CD enzyme in a reaction which releases OH(-). This elevates the steady-state pH within the hydrogel as compared to the exterior solution. In response, the 2NPh is deprotonated. The increased solubility of the phenolate species as compared to that of the neutral phenols causes a hydrogel swelling which red-shifts the IPCCA diffraction. This photonic crystal IPCCA senses physiologically relevant creatinine levels, with a detection limit of 6 microM, at physiological pH and salinity. This sensor also determines physiological levels of creatinine in human blood serum samples. This sensing technology platform is quite general. It may be used to fabricate photonic crystal sensors for any species for which there exists an enzyme which catalyzes it to release H(+) or OH(-). PMID:14995215

Sharma, Anjal C; Jana, Tushar; Kesavamoorthy, Rasu; Shi, Lianjun; Virji, Mohamed A; Finegold, David N; Asher, Sanford A

2004-03-10

143

Urea Concentration and Haemodialysis Dose  

PubMed Central

Background. Dialysis dose is commonly defined as a clearance scaled to some measure of body size, but the toxicity of uraemic solutes is probably associated more to their concentrations than to their clearance. Methods. 619 dialysis sessions of 35 patients were modified by computer simulations targeting a constant urea clearance or a constant urea concentration. Results. Urea generation rate G varied widely in dialysis patients, rather independently of body size. Dialysing to eKt/V 1.2 in an unselected patient population resulted in great variations in time-averaged concentration (TAC) and average predialysis concentration (PAC) of urea (5.9–40.2 and 8.6–55.8?mmol/L, resp.). Dialysing to equal clearance targets scaled to urea distribution volume resulted in higher concentrations in women. Dialysing to the mean HEMO-equivalent TAC or PAC (17.7 and 25.4?mmol/L) required extremely short or long treatment times in about half of the sessions. Conclusions. The relation between G and V varies greatly and seems to be different in women and men. Dialysing to a constant urea concentration may result in unexpected concentrations of other uraemic toxins and is not recommended, but high concentrations may justify increasing the dose despite adequate eKt/V, std?EKR, or std?K/V.

Vartia, Aarne

2013-01-01

144

Reference Ranges for Serum Uric Acid among Healthy Assamese People.  

PubMed

This study was designed to establish reference ranges for serum uric acid among healthy adult Assamese population. Samples from 1470 aged 35-86 years were used to establish age and sex related reference range by the centile method (central 95 percentile) for serum uric acid level. There were 51% (n = 754) males and 49% (n = 716) females; 75.9% (n = 1115) of them were from urban area and the rest 24.1% (n = 355) were from the rural area. Majority of the population were nonvegetarian (98.6%, n = 1450) and only 1.4% (n = 20) were vegetarian. The mean age, weight, height, and uric acid of the studied group were 53.6 ± 11.3 years, 62.6 ± 10.5?kg, 160 ± 9.4?cm, and 5.5 ± 1.4?mg/dL, respectively. There is a statistically significant difference in the mean value of the abovementioned parameters between male and female. The observed reference range of uric acid in the population is 2.6-8.2?mg/dL which is wider than the current reference range used in the laboratory. Except gender (P < 0.0001), we did not find any significant relation of uric acid with other selected factors. PMID:24672726

Das, Madhumita; Borah, N C; Ghose, M; Choudhury, N

2014-01-01

145

Renal Transport of Uric Acid: Evolving Concepts and Uncertainties  

PubMed Central

In addition to its role as a metabolic waste product, uric acid has been proposed to be an important molecule with multiple functions in human physiology and pathophysiology and may be linked to human diseases beyond nephrolithiasis and gout. Uric acid homeostasis is determined by the balance between production, intestinal secretion, and renal excretion. The kidney is an important regulator of circulating uric acid levels, by reabsorbing around 90% of filtered urate, while being responsible for 60–70% of total body uric acid excretion. Defective renal handling of urate is a frequent pathophysiologic factor underpinning hyperuricemia and gout. In spite of tremendous advances over the past decade, the molecular mechanisms of renal urate transport are still incompletely understood. Many transport proteins are candidate participants in urate handling, with URAT1 and GLUT9 being the best characterized to date. Understanding these transporters is increasingly important for the practicing clinician as new research unveils their physiology, importance in drug action, and genetic association with uric acid levels in human populations. The future may see the introduction of new drugs that specifically act on individual renal urate transporters for the treatment of hyperuricemia and gout.

Bobulescu, Ion Alexandru; Moe, Orson W.

2013-01-01

146

Uric Acid and Insulin Sensitivity and Risk of Incident Hypertension  

PubMed Central

Background Uric acid, insulin sensitivity, and endothelial dysfunction may be important in the development of hypertension. Corresponding circulating biomarkers are associated with risk of hypertension in many studies. However, because these factors may be interrelated, whether they independently influence risk is unknown. Methods Among 1,496 young women who did not have hypertension at baseline, we prospectively analyzed the association between fasting plasma levels of uric acid, insulin, triglycerides, the insulin sensitivity index, two biomarkers associated with endothelial dysfunction (homocysteine and soluble intercellular adhesion molecule-1), and the odds of incident hypertension. Odds ratios were adjusted for standard risk factors, and then for all biomarkers, plus estimated glomerular filtration rate and total cholesterol. The population attributable risk was estimated for biomarkers significantly associated with hypertension. Results All biomarkers were associated with incident hypertension after adjustment for standard hypertension risk factors. However, after simultaneously controlling for all biomarkers, eGFR, and total cholesterol, only uric acid and insulin were independently associated with incident hypertension. Comparing the highest to lowest quartile of uric acid, the OR was 1.89 (1.26-2.82). A similar comparison yielded an OR=2.03 (1.35-3.05) for insulin. Using an estimated basal incidence rate of 14.6 per 1000/year, 30.8% of all hypertension occurring in young women annually is associated with uric acid levels ?3.4 mg/dL. For insulin levels ?2.9 ?IU/mL, this proportion is 24.2%. Conclusions Differences in uric acid and insulin robustly and substantially influence the risk of developing hypertension among young women. Measuring these biomarkers in clinical practice may identify higher risk individuals.

Forman, John P.; Choi, Hyon; Curhan, Gary C.

2009-01-01

147

Adherence to uric acid treatment guidelines in a rheumatology clinic.  

PubMed

The aim of this study was to evaluate adherence to recommended serum uric acid levels in the rheumatology outpatients department of a university teaching hospital. We performed a retrospective study of all patients with a definitive diagnosis of gout attending our subspecialty gout clinic between 1 January 2010 and 31 December 2010. We evaluated adherence with two recently suggested uric acid thresholds, <300 ?mol/L (<5 mg/dL) and <360 ?mol/L (<6 mg/dL). Patient management was judged to adhere to the guidelines if either (1) the latest serum uric acid level was less than the specified guideline targets or (2) uric acid-lowering therapy was titrated upwards or the agent changed if the serum uric acid was above the guideline targets. One hundred two patients with a definitive diagnosis of gout attended the outpatients department between 1 January 2010 and 31 December 2010 and were included in the study. Median serum uric acid level was 331 ?mol/L (IQR 276-456 ?mol/L). Eighty-six patients (84 %) were treated with allopurinol, six patients (6 %) were treated with febuxostat (one of whom also received probenecid), and one with rasburicase. In 80 patients (78 %), the management adhered to a target guideline of <360 ?mol/L (<6 mg/dL). In 66 patients (65 %), the management adhered to a target guideline of <300 ?mol/L (<5 mg/dL). A treat-to-target approach has the potential to improve patient outcomes in the management of gouty arthritis. Our study shows encouraging results with the majority of patients on appropriate therapy and reaching recommended targets. PMID:22948225

Conway, Richard; Coughlan, Robert J; Carey, John J

2012-12-01

148

Serum uric acid and target organ damage in essential hypertension  

PubMed Central

Background Hypertension is a major risk factor for cardiovascular mortality, as it acts through its effects on target organs, such as the heart and kidneys. Hyperuricemia increases cardiovascular risk in patients with hypertension. Objective To assess the relationship between serum uric acid and target organ damage (left ventricular hypertrophy and microalbuminuria) in untreated patients with essential hypertension. Patients and methods: A cross-sectional study was carried out in 130 (85 females, 45 males) newly diagnosed, untreated patients with essential hypertension. Sixty-five healthy age- and sex-matched non-hypertensive individuals served as controls for comparison. Left ventricular hypertrophy was evaluated by cardiac ultrasound scan, and microalbuminuria was assessed in an early morning midstream urine sample by immunoturbidimetry. Blood samples were collected for assessing uric acid levels. Results Mean serum uric acid was significantly higher among the patients with hypertension (379.7±109.2 ?mol/L) than in the controls (296.9±89.8 ?mol/L; P<0.001), and the prevalence of hyperuricemia was 46.9% among the hypertensive patients and 16.9% among the controls (P<0.001). Among the hypertensive patients, microalbuminuria was present in 54.1% of those with hyperuricemia and in 24.6% of those with normal uric acid levels (P=0.001). Similarly, left ventricular hypertrophy was more common in the hypertensive patients with hyperuricemia (70.5% versus 42.0%, respectively; P=0.001). There was a significant linear relationship between mean uric acid levels and the number of target organ damage (none versus one versus two: P=0.012). Conclusion These results indicate that serum uric acid is associated with target organ damage in patients with hypertension, even at the time of diagnosis; thus, it is a reliable marker of cardiovascular damage in our patient population.

Ofori, Sandra N; Odia, Osaretin J

2014-01-01

149

Stable carbon and nitrogen isotope analysis of avian uric acid.  

PubMed

We report results obtained using a new technique developed to measure the stable-isotope composition of uric acid isolated from bird excreta (guano). Results from a diet-switch feeding trial using zebra finches suggest that the delta(13)C of uric acid in the guano equilibrates with the diet of the bird within 3 days of a change in diet, while the equilibration time for delta(15)N may be longer. The average carbon isotope discrimination between uric acid and food before the diet switch was +0.34 +/- 1 per thousand (1sigma) while after the diet switch this increased slightly to +0.83 +/- 0.7 per thousand (1sigma). Nitrogen isotope discrimination was +1.3 +/- 0.3 per thousand (1sigma) and +0.3 +/- 0.3 per thousand (1sigma) before and after the diet switch; however, it is possible that the nitrogen isotope values did not fully equilibrate with diet switch over the course of the experiment. Analyses of other chemical fractions of the guano (organic residue after uric acid extraction and non-uric acid organics solubilised during extraction) suggest a total range of up to 3 per thousand for both delta(13)C and delta(15)N values in individual components of a single bulk guano sample. The analysis of natural samples from a range of terrestrial and marine species demonstrates that the technique yields isotopic compositions consistent with the known diets of the birds. The results from natural samples further demonstrate that multiple samples from the same species collected from the same location yield similar results, while different species from the same location exhibit a range of isotopic compositions indicative of different dietary preferences. Given that many samples of guano can be rapidly collected without any requirement to capture specimens for invasive sampling, the stable-isotope analysis of uric acid offers a new, simple and potentially powerful tool for studying avian ecology and metabolism. PMID:18837063

Bird, Michael I; Tait, Elaine; Wurster, Christopher M; Furness, Robert W

2008-11-01

150

Milk and soy-protein ingestion: acute effect on serum uric acid concentration13  

Microsoft Academic Search

Acute effect of the ingestion of 80 g each of casein, lactalbumin, and soybean isolate on serum and urinary uric acid concentrations was investigated in 10 healthy subjects. Serum and urinary uric acid concentrations were measured be- fore and after the ingestion ofproteins. Serum uric acid decreased significantly 3 h after ingestion of lactalbumin and casein but increased after soybean

Dominique R Garrel; Maurice Verdy; Claude PetitClerc; Christophe Martin; Danielle Brul; Pavel Hamet

151

Effect of Oestrogen Therapy on Plasma and Urinary Levels of Uric Acid  

Microsoft Academic Search

Uric acid clearance studies were carried out on a low-purine diet in 22 trans-sexual men before and during oestrogen therapy for this condition (stilboestrol in 21 cases, ethinyloestradiol in one). Plasma uric acid fell in 15 of the subjects and urinary uric acid rose in 17 of 20 subjects in whom satisfactory collections were obtained. These changes are significant and

Anne Nicholls; M. L. Snaith; J. T. Scott

1973-01-01

152

[Amylase-creatinine clearance ratios in burned patients (author's transl)].  

PubMed

The amylase/creatinine clearance ratio (ACCR) has been examined every 3 days, in 34 burned patients during the 20 days following the accident. This ratio was often abnormal since it was found increased at least on one occasion, in 75% of these patients, to be compared with 23 and 13% for amylase in serum and urine respectively. In another group of 9 burned patients, the ACCR was monitored for time-period between 10 to 52 days. It was observed that a high frequency in increased ACCR was associated with a fatal outcome. Finally simultaneous measurements of ACCR and of the beta2 microglobulin/creatinine clearance ratio (MCCR) showed that increased ACCR were statistically associated with increased MCCR suggesting a decreased renal tubular reabsorption of low molecular weight proteins in these burned patients. PMID:360162

Minaire, Y; Marichy, J; Forichon, J; Motin, J

1978-09-01

153

A Double-edged Sword: Uric Acid and Neurological Disorders  

PubMed Central

Uric Acid (UA), historically considered as a waste of cellular metabolism, has now received increasing attention because it was found to directly participate in the pathogenesis of many human diseases including neurological disorders. On one hand, low levels of UA are detrimental to the neurons because of its induction it impairs antioxidant capacity in the cell. High levels of UA, on the other hand, lead to an inflammatory response contributing to gout or neuroprotection. In this review, we summarize this biphasic function of uric acid and highlight potential therapeutic targets to treat UA-related neurological diseases.

Fang, Pu; Li, Xinyuan; Luo, Jin Jun; Wang, Hong; Yang, Xiao-feng

2014-01-01

154

UV-induced effects on chlorination of creatinine.  

PubMed

Ultraviolet (UV) irradiation is commonly employed for water treatment in swimming pools to complement conventional chlorination, and to reduce the concentration of inorganic chloramine compounds. The approach of combining UV irradiation and chlorination has the potential to improve water quality, as defined by microbial composition. However, relatively little is known about the effects of this process on water chemistry. To address this issue, experiments were conducted to examine the effects of sequential UV254 irradiation/chlorination, as will occur in recirculating system of swimming pools, on disinfection byproduct (DBP) formation. Creatinine, which is present in human sweat and urine, was selected as the target precursor for these experiments. Enhanced formation of dichloromethylamine (CH3NCl2) and inorganic chloramines was observed to result from post-chlorination of UV-irradiated samples. Chlorocreatinine was found to be more sensitive to UV254 irradiation than creatinine; UV254 irradiation of chlorocreatinine resulted in opening of the ring structure, thereby yielding a series of intermediates that were more susceptible to free chlorine attack than their parent compound. The quantum yields for photodegradation of creatinine and chlorocreatinine at 254 nm were estimated at 0.011 ± 0.002 mol/E and 0.144 ± 0.011 mol/E, respectively. The N-Cl bond was found to be common to UV-sensitive chlorinated compounds (e.g., inorganic chloramines, CH3NCl2, and chlorocreatinine); compounds that were less susceptible to UV-based attack generally lacked the N-Cl bond. This suggested that the N-Cl bond is susceptible to UV254 irradiation, and cleavage of the N-Cl bond appears to open or promote reaction pathways that involve free chlorine, thereby enhancing formation of some DBPs and promoting loss of free chlorine. Proposed reaction mechanisms to describe this behavior based on creatinine as a precursor are presented. PMID:23863372

Weng, Shih Chi; Li, Jing; Wood, Karl V; Kenttämaa, Hilkka I; Williams, Peggy E; Amundson, Lucas M; Blatchley, Ernest R

2013-09-15

155

Serum creatinine concentrations SGOT and SGPT activities and lead exposure  

Microsoft Academic Search

Summary In a group of workers exposed to lead and a group of people representing the general urban and rural population of Finland the serum creatinine (S-Great) concentrations of 1342 men and 377 women, glutamic oxaloacetic acid transaminase (S-GOT) activities of 1464 men and 510 women, and glutamic pyruvic acid transaminase (S-GPT) activities of 377 men and 235 women were

Sakari Tola; Clae's-Henrik Nordman

1977-01-01

156

Enzymeless creatinine estimation using poly(3,4-ethylenedioxythiophene) -?-cyclodextrin  

Microsoft Academic Search

A novel enzymeless biosensor has been constructed for the quantitative estimation of creatinine using ?-cyclodextrin (?CD) incorporated poly-3,4-ethylenedioxythiophene (PEDOT) modified glassy carbon electrode (GCE). The PEDOT film with and without ?CD was deposited on a GCE by electropolymerization of EDOT from an aqueous solution containing lithium perchlorate and ?CD. Polymer films were characterized by UV–visible spectroscopy, cyclic voltammetry and scanning

Thangavel Naresh Kumar; Arjunan Ananthi; Jayaraman Mathiyarasu; James Joseph; Kanala Lakshminarasimha Phani; Venkatraman Yegnaraman

2011-01-01

157

Creatinine Kinetics and the Definition of Acute Kidney Injury  

PubMed Central

Acute kidney injury (AKI) is a common and devastating medical condition, but no widely accepted definition exists. A recent classification system by the Acute Dialysis Quality Initiative (RIFLE) defines AKI largely by percentage increases in serum creatinine (SCr) over baseline. The Acute Kidney Injury Network defines the first stage by either an absolute or a percentage increase in SCr. To examine the implications of various definitions, we solved differential equations on the basis of mass balance principles. We simulated creatinine kinetics after AKI in the setting of normal baseline kidney function and stages 2, 3, and 4 chronic kidney disease (CKD). The percentage changes in SCr after severe AKI are highly dependent on baseline kidney function. Twenty-four hours after a 90% reduction in creatinine clearance, the rise in SCr was 246% with normal baseline kidney function, 174% in stage 2 CKD, 92% in stage 3 CKD, and only 47% in stage 4 CKD. By contrast, the absolute increase was nearly identical (1.8 to 2.0 mg/dl) across the spectrum of baseline kidney function. Time to reach a 50% increase in SCr was directly related to baseline kidney function: From 4 h (normal baseline) up to 27 h for stage 4 CKD. By contrast, the time to reach a 0.5-mg/dl increase in SCr was virtually identical after moderate to severe AKI (>50% reduction in creatinine clearance). We propose an alternative definition of AKI that incorporates absolute changes in SCr over a 24- to 48-h time period.

Waikar, Sushrut S.; Bonventre, Joseph V.

2009-01-01

158

Creatinine kinetics and the definition of acute kidney injury.  

PubMed

Acute kidney injury (AKI) is a common and devastating medical condition, but no widely accepted definition exists. A recent classification system by the Acute Dialysis Quality Initiative (RIFLE) defines AKI largely by percentage increases in serum creatinine (SCr) over baseline. The Acute Kidney Injury Network defines the first stage by either an absolute or a percentage increase in SCr. To examine the implications of various definitions, we solved differential equations on the basis of mass balance principles. We simulated creatinine kinetics after AKI in the setting of normal baseline kidney function and stages 2, 3, and 4 chronic kidney disease (CKD). The percentage changes in SCr after severe AKI are highly dependent on baseline kidney function. Twenty-four hours after a 90% reduction in creatinine clearance, the rise in SCr was 246% with normal baseline kidney function, 174% in stage 2 CKD, 92% in stage 3 CKD, and only 47% in stage 4 CKD. By contrast, the absolute increase was nearly identical (1.8 to 2.0 mg/dl) across the spectrum of baseline kidney function. Time to reach a 50% increase in SCr was directly related to baseline kidney function: From 4 h (normal baseline) up to 27 h for stage 4 CKD. By contrast, the time to reach a 0.5-mg/dl increase in SCr was virtually identical after moderate to severe AKI (>50% reduction in creatinine clearance). We propose an alternative definition of AKI that incorporates absolute changes in SCr over a 24- to 48-h time period. PMID:19244578

Waikar, Sushrut S; Bonventre, Joseph V

2009-03-01

159

Contact allergy to diazolidinyl urea (Germall II).  

PubMed

4 cases of contact allergy to diazolidinyl urea (Germall II) in a "hypoallergenic" brand of cosmetics are described. 2 patients sensitized by these cosmetics were not allergic to formaldehyde. 2 other patients already sensitive to formaldehyde had exacerbations of dermatitis due to diazolidinyl urea. The following tentative conclusions were drawn. (i) Contact allergy to diazolidinyl urea may or may not be due to formaldehyde sensitivity. (ii) Patients allergic to formaldehyde may suffer contact allergic reactions from the use of cosmetics containing diazolidinyl urea. (iii) Patients sensitized to diazolidinyl urea may cross-react to imidazolidinyl urea and vice-versa. (iv) It is suggested that the sensitizing potential of diazolidinyl urea is greater than that of imidazolidinyl urea. (v) Aq. solutions may be preferable to pet. for patch testing with diazolidinyl urea. PMID:3378427

de Groot, A C; Bruynzeel, D P; Jagtman, B A; Weyland, J W

1988-04-01

160

Acute urea toxicity in sheep.  

PubMed Central

Twenty-seven sheep were assigned to three groups in order to study acute urea toxicity. Groups I, II and III were dosed with 0.5, 0.6 annd 0.75 g/kg of urea, respectively. The mean survival times were 165, 109 and 60 minutes, respectively. The following clinical signs such as pronounced muscle fasciculation, trembling, grinding teeth, ataxia, lateral recumbency, bloating, regurgitation, hyperesthesia, mydriasis and convulsions were observed. Anuria and lack of salivation were also present. The primary cause of death in this study was due to respiratory arrest and not cardiovascular collapse. Plasma examinations showed a marked increase in glucose, ammonia and urea levels but no change in ketone body concentration.

Edjtehadi, M; Szabuniewicz, M; Emmanuel, B

1978-01-01

161

Uric acid and xanthine oxidoreductase in wound healing.  

PubMed

Chronic wounds are an important health problem because they are difficult to heal and treatment is often complicated, lengthy and expensive. For a majority of sufferers the most common outcomes are long-term immobility, infection and prolonged hospitalisation. There is therefore an urgent need for effective therapeutics that will enhance ulcer healing and patient quality of life, and will reduce healthcare costs. Studies in our laboratory have revealed elevated levels of purine catabolites in wound fluid from patients with venous leg ulcers. In particular, we have discovered that uric acid is elevated in wound fluid, with higher concentrations correlating with increased wound severity. We have also revealed a corresponding depletion in uric acid precursors, including adenosine. Further, we have revealed that xanthine oxidoreductase, the enzyme that catalyses the production of uric acid, is present at elevated levels in wound fluid. Taken together, these findings provide evidence that xanthine oxidoreductase may have a function in the formation or persistence of chronic wounds. Here we describe the potential function of xanthine oxidoreductase and uric acid accumulation in the wound site, and the effect of xanthine oxidoreductase in potentiating the inflammatory response. PMID:24357442

Fernandez, Melissa L; Upton, Zee; Shooter, Gary K

2014-02-01

162

Uric acid as radical scavenger and antioxidant in the heart  

Microsoft Academic Search

Uric acid (UA) is released from the heart of many species, including man, and its site of formation has been shown to be the microvascular endothelium. Since UA reacts with oxygen radicals in vitro, experiments were conducted on guinea pig hearts perfused with Krebs-Henseleit buffer (KHB) to evaluate whether the formation of UA could afford protection from damage by radicals

B. F. Becker; N. Reinholz; T. Özçelik; B. Leipert; E. Gerlach

1989-01-01

163

Elevated serum uric acid — a facet of hyperinsulinaemia  

Microsoft Academic Search

Summary  In a representative sample of the adult Jewish population in Israel (n=1016) excluding known diabetic patients and individuals on antihypertensive medications, serum uric acid showed a positive association with plasma insulin response (sum of 1- and 2-hour post glucose load levels) in both males (r=0.316, pr=0.236, pp

M. Modan; H. Halkin; A. Karasik; A. Lusky

1987-01-01

164

Relationship between Uric Acid Level and Achievement Motivation. Final Report.  

ERIC Educational Resources Information Center

In an investigation of the relationship of uric acid (a metabolic end product) to achievement, this study hypothesized that a person's serum urate level (a factor often associated with gout) is positively related to achievement need as well as indicators of actual achievement. (Speed of promotion and number of yearly publications were chosen as…

Mueller, Ernst F.; French, John R. P., Jr.

165

Effects of Strenuous Physical Training on Serum Uric Acid Levels.  

National Technical Information Service (NTIS)

In this study a fall in serum uric acid (SUA) concentration was associated with the intensive physical exercise over a period of 12 weeks. It was concluded that the chronic effects of a physical training program do not necessarily mimic the temporary effe...

L. H. Cronau P. J. Rasch J. W. Hamby H. J. Burns

1972-01-01

166

Chemodissolution of Urinary Uric Acid Stones by Alkali Therapy  

Microsoft Academic Search

Experience with chemodissolution of uric acid stones in 30 patients is presented. Chemodissolution was achieved either with infusion of 0.16 M i.v. lactate or oral sodium bicarbonate, in addition to liberal fluid intake and allopurinol wherever indicated. In some cases direct chemodissolution by in situ irrigation with sodium bicarbonate solution was done after an initial percutaneous nephrostomy. Seven patients presented

S. K. Sharma; R. Indudhara

1992-01-01

167

Uric acid as one of the important factors in multifactorial disorders - facts and controversies  

PubMed Central

With considering serum concentration of the uric acid in humans we are observing hyperuricemia and possible gout development. Many epidemiological studies have shown the relationship between the uric acid and different disorders such are obesity, metabolic syndrome, hypertension and coronary artery disease. Clinicians and investigators recognized serum uric acid concentration as very important diagnostic and prognostic factor of many multifactorial disorders. This review presented few clinical conditions which are not directly related to uric acid, but the concentrations of uric acid might have a great impact in observing, monitoring, prognosis and therapy of such disorders. Uric acid is recognized as a marker of oxidative stress. Production of the uric acid includes enzyme xanthine oxidase which is involved in producing of radical-oxigen species (ROS). As by-products ROS have a significant role in the increased vascular oxidative stress and might be involved in atherogenesis. Uric acid may inhibit endothelial function by inhibition of nitric oxide-function under conditions of oxidative stress. Down regulation of nitric oxide and induction of endothelial dysfunction might also be involved in pathogenesis of hypertension. The most important and well evidenced is possible predictive role of uric acid in predicting short-term outcome (mortality) in acute myocardial infarction (AMI) patients and stroke. Nephrolithiasis of uric acid origin is significantly more common among patients with the metabolic syndrome and obesity. On contrary to this, uric acid also acts is an “antioxidant”, a free radical scavenger and a chelator of transitional metal ions which are converted to poorly reactive forms.

Pasalic, Daria; Marinkovic, Natalija; Feher-Turkovic, Lana

2012-01-01

168

Serum creatinine levels in the US population: Third National Health and Nutrition Examination Survey  

Microsoft Academic Search

This report describes the distribution of serum creatinine levels by sex, age, and ethnic group in a representative sample of the US population. Serum creatinine level was evaluated in the third National Health and Nutrition Examination Survey (NHANES III) in 18,723 participants aged 12 years and older who were examined between 1988 and 1994. Differences in mean serum creatinine levels

CA Jones; GM McQuillan; JW Kusek; Eberhardt; WH Herman; J Coresh; M Salive; LY Agodoa

1998-01-01

169

Association of serum uric acid with ischemic stroke.  

PubMed

The present study has examined the association between ischemic stroke and hyperuricemia in Bangladeshi population. This age and sex matched case control study was carried out in the Department of Neurology, Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, Bangladesh during the period of January 2007 to December 2008. A total of 120 subjects were included in this study, among them 60 were cases and another 60 were controls. Data were collected purposively. Multiple logistic regressions were done to identify the risk factors for ischemic stroke. In this study 68.3% were male and 31.7% were female in both the groups. Male and female ratio of stroke patients was 2.16:1. Mean±SD of serum uric acid level of case and control group was 4.94±1.76 and 3.72±1.09 respectively. Among the case group 76.7% had normal and 23.3% had abnormal serum uric acid level. On the other hand, 93.3% respondents of control group had normal and 6.7% had abnormal serum uric acid (SUA) level. Significant differences was found between case and control group in term of SUA level (p<0.05). Since SUA level is a quantitative numerical variable, an increase in 1mg/dl has a 47.0% (95% CI 1.0% to 2.16%) increase in odds ratio (OR) of having ischemic stroke. This 47.0% is obtained by taking OR for uric acid-1. Elevated serum uric acid level is not significant for ischemic stroke among the Bangladeshi population. PMID:23715356

Khalil, M I; Islam, M J; Ullah, M A; Khan, R K; Munira, S; Haque, M A; Mamun, M A; Islam, M T; Khan, M H

2013-04-01

170

Urea Biosynthesis Using Liver Slices  

ERIC Educational Resources Information Center

Presented is a practical scheme to enable introductory biology students to investigate the mechanism by which urea is synthesized in the liver. The tissue-slice technique is discussed, and methods for the quantitative analysis of metabolites are presented. (Author/SL)

Teal, A. R.

1976-01-01

171

Hyperfiltration Affects Accuracy of Creatinine eGFR Measurement  

PubMed Central

Summary Background and objectives Surrogate markers such as creatinine, cystatin C (CysC), and beta trace protein (BTP) have been used to estimate GFR (eGFR). The accuracy of eGFR may be altered with hyperfiltration and differences in filtration fraction (FF). It is hypothesized that the accuracy of creatinine for eGFR may be affected by hyperfiltration and different effective renal plasma flow (ERPF). Design, setting, participants, & measurements A total of 127 pediatric patients with various renal diseases underwent simultaneous measurements of GFR using 51Cr-EDTA renal scan and ERPF (131I-hippurate clearance) to calculate the FF (FF = GFR/ERPF). The eGFRs were calculated using the commonly used Schwartz (creatinine), Filler (CysC), and Benlamri (BTP) formulas. Agreement of the eGFRs with the measured isotope GFRs was assessed by Bland–Altman plots. Correlation analysis was performed using nonparametric tests to compare FF with eGFR ? GFR. Results The 127 children at a median age (with 25th percentile, 75th percentile) of 11.9 (8.5, 14.9) years had a mean 51Cr EDTA-GFR of 100.6 ± 32.1 ml/min per 1.73 m2 and a median 131I-hippurate clearance (ERPF) of 588 (398,739) ml/min per 1.73 m2. Mean FF was 17.7 ± 4.5% with no correlation between the FF and the error (eGFR ? GFR) for CysC and BTP eGFR, whereas there was a significant negative correlation between the error for Schwartz eGFR and FF. Conclusions There is a significant negative correlation between the error for the Schwartz eGFR and the FF. CysC and BTP are not affected by differences in FF.

Huang, Shih-Han S.; Sharma, Ajay P.; Yasin, Abeer; Lindsay, Robert M.; Clark, William F.

2011-01-01

172

Decreased abundance of collecting duct urea transporters UT-A1 and UT-A3 with ECF volume expansion.  

PubMed

Clinical disorders of extracellular fluid (ECF) volume regulation are often associated with changes in plasma urea concentration. To investigate possible renal causes, we measured the relative abundance of the urea transporters UT-A1, UT-A2, and UT-A3 in renal medulla of rats with aldosterone-induced NaCl retention. ECF volume-expanded rats received aldosterone by osmotic minipump plus a diet containing a high level of NaCl. Control rats received the same infusion of aldosterone plus a virtually NaCl-free diet, which prevented ECF volume expansion. Preliminary measurements demonstrated transient positive Na and water balance, decreased serum urea concentration, and increased urea clearance, but no change in creatinine clearance. Immunoblotting of homogenates from inner medulla showed a marked decrease in the abundance of the collecting duct urea transporters UT-A1 and UT-A3. There were no differences in the abundance of UT-A2, aquaporin (AQP)-2, AQP-3, or AQP-4 in ECF volume-expanded rats vs. controls. Time course experiments demonstrated that changes in UT-A1 abundance paralleled the fall in serum urea concentration after the switch from a low-NaCl to a high-NaCl diet, whereas the fall in UT-A3 abundance was delayed. Candesartan administration markedly decreased the abundance of UT-A1 and UT-A3 in the renal inner medulla, which is consistent with a role for the angiotensin II type 1 receptor in urea transport regulation. The results support the view that ECF-related changes in serum urea concentration are mediated, at least in part, through altered urea transporter abundance. PMID:11880317

Wang, Xiao-Yan; Beutler, Kathleen; Nielsen, Jakob; Nielsen, Søren; Knepper, Mark A; Masilamani, Shyama

2002-04-01

173

40 CFR 721.9892 - Alkylated urea.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Alkylated urea. 721.9892 Section 721.9892 ...Chemical Substances § 721.9892 Alkylated urea. (a) Chemical substance and significant...substance identified generically as an alkylated urea (PMN P-93-1649) is subject to...

2013-07-01

174

Urea kinetic modeling for CRRT.  

PubMed

Urea kinetic modeling (UKM) for dialysis quantification and prescription, although widely used in chronic renal failure (CRF), has been largely absent in the acute setting. A quantitative approach to prescription of continuous renal replacement therapies (CRRTs) for acute renal failure (ARF) based on UKM is presented. For patients with a relatively constant urea generation rate, G, who are receiving a fixed dose of CRRT, blood urea nitrogen (BUN) falls in an exponential fashion, approaching a plateau level after 3 to 4 days of continuous treatment. The CRRT clearance, K, necessary to achieve a desired plateau value of BUN, Cgoal, may be computed as G/Cgoal x K for all but predilutional CRRT modalities may be calculated as equal to the effluent (dialysate plus ultrafiltrate) flow rate from the filter. Urea mass balance equations are proposed for the determination of patient G value either during the pretreatment rise in BUN or during the decline in BUN with CRRT. In the absence of a reliable estimate of patient G, a reasonable CRRT starting prescription is to set the filter effluent rate in liters per hour (approximately K) to 1.2 times the patient's body weight in kilograms divided by the desired Cgoal in milligrams per deciliter. This relationship assumes moderate hypercatabolism (normalized protein catabolic rate = 2.0 g/kg/d) and patient urea distribution volume equal to 60% of body weight. For Cgoal = 60 mg/dL, this reduces to an easily remembered formula for K (in L/hr) of twice the patient's body weight divided by 100. PMID:9372972

Garred, L; Leblanc, M; Canaud, B

1997-11-01

175

The SLC14 gene family of urea transporters  

Microsoft Academic Search

Carrier-mediated urea transport allows rapid urea movement across the cell membrane, which is particularly important in the process of urinary concentration and for rapid urea equilibrium in non-renal tissues. Urea transporters mediate passive urea uptake that is inhibited by phloretin and urea analogues. Facilitated urea transporters are divided into two classes: (1) the renal tubular\\/testicular type of urea transporter, UT-A1

Chairat Shayakul; Matthias A. Hediger

2004-01-01

176

Altered Nitrogen Balance and Decreased Urea Excretion in Male Rats Fed Cafeteria Diet Are Related to Arginine Availability  

PubMed Central

Hyperlipidic diets limit glucose oxidation and favor amino acid preservation, hampering the elimination of excess dietary nitrogen and the catabolic utilization of amino acids. We analyzed whether reduced urea excretion was a consequence of higher NOx; (nitrite, nitrate, and other derivatives) availability caused by increased nitric oxide production in metabolic syndrome. Rats fed a cafeteria diet for 30 days had a higher intake and accumulation of amino acid nitrogen and lower urea excretion. There were no differences in plasma nitrate or nitrite. NOx and creatinine excretion accounted for only a small part of total nitrogen excretion. Rats fed a cafeteria diet had higher plasma levels of glutamine, serine, threonine, glycine, and ornithine when compared with controls, whereas arginine was lower. Liver carbamoyl-phosphate synthetase I activity was higher in cafeteria diet-fed rats, but arginase I was lower. The high carbamoyl-phosphate synthetase activity and ornithine levels suggest activation of the urea cycle in cafeteria diet-fed rats, but low arginine levels point to a block in the urea cycle between ornithine and arginine, thereby preventing the elimination of excess nitrogen as urea. The ultimate consequence of this paradoxical block in the urea cycle seems to be the limitation of arginine production and/or availability.

Sabater, David; Arriaran, Sofia; Fernandez-Lopez, Jose-Antonio; Romero, Maria del Mar; Remesar, Xavier

2014-01-01

177

Altered nitrogen balance and decreased urea excretion in male rats fed cafeteria diet are related to arginine availability.  

PubMed

Hyperlipidic diets limit glucose oxidation and favor amino acid preservation, hampering the elimination of excess dietary nitrogen and the catabolic utilization of amino acids. We analyzed whether reduced urea excretion was a consequence of higher NO x ; (nitrite, nitrate, and other derivatives) availability caused by increased nitric oxide production in metabolic syndrome. Rats fed a cafeteria diet for 30 days had a higher intake and accumulation of amino acid nitrogen and lower urea excretion. There were no differences in plasma nitrate or nitrite. NO x and creatinine excretion accounted for only a small part of total nitrogen excretion. Rats fed a cafeteria diet had higher plasma levels of glutamine, serine, threonine, glycine, and ornithine when compared with controls, whereas arginine was lower. Liver carbamoyl-phosphate synthetase I activity was higher in cafeteria diet-fed rats, but arginase I was lower. The high carbamoyl-phosphate synthetase activity and ornithine levels suggest activation of the urea cycle in cafeteria diet-fed rats, but low arginine levels point to a block in the urea cycle between ornithine and arginine, thereby preventing the elimination of excess nitrogen as urea. The ultimate consequence of this paradoxical block in the urea cycle seems to be the limitation of arginine production and/or availability. PMID:24707502

Sabater, David; Agnelli, Silvia; Arriarán, Sofía; Fernández-López, José-Antonio; Romero, María Del Mar; Alemany, Marià; Remesar, Xavier

2014-01-01

178

The amylase creatinine clearance ratio in acute pancreatitis.  

PubMed

One hundred and twenty-two patients have been studied in order to evaluate the usefulness of the amylase creatinine clearance ratio (ACCR) as a simple diagnostic test for acute pancreatitis. Sixteen out of 17 patients with acute pancreatitis had significant elevations in ACCR; in only 10 of these 17 cases was the serum amylase greater than 1200iu/l. The mean ACCR was within the normal range in control patients, in patients with chronic gastro-intestinal disease and in patients with acute abdominal conditions excluding pancreatitis; however, the mean serum amylase was significantly greater in patients with acute abdominal conditions than in the control group (P less than 0-05). The ACCR remained significantly elevated in patients with acute pancreatitis for longer than either serum or urine amylase values. The findings of the study suggest that the amylase creatinine clearance ratio is a simple yet reliable diagnostic test which could be used when screening patients suspected of having acute pancreatitis. PMID:890263

Murray, W R; Mackay, C

1977-03-01

179

Relationship Between Serum Uric Acid Levels, Metabolic Syndrome, and Arterial Stiffness in Korean  

PubMed Central

Background and Objectives Associations have been reported between the serum uric acid (SUA) level, metabolic syndrome (MS), and atherosclerosis. We have determined the relationship between the SUA level, MS, and arterial stiffness in Korean. Subjects and Methods Cross-sectional data from 1,276 adults who underwent routine laboratory tests and pulse wave velocity (PWV) measurements during a health check-up were analyzed in a gender-specific manner. None of the participants had atherosclerotic cardiovascular disease, diabetes, renal disease, or systemic disease, or were under treatment which would affect SUA levels, or taking medications for hypertension or dyslipidemia. Results After adjustment for age, smoking status, total cholesterol (TC), and creatinine, the odds ratios (ORs, 95% confidence interval) of gender-specific quartiles of SUA for MS were 1.0, 1.28 (0.66-2.47), 1.46 (0.76-2.82), and 2.21 (1.15-4.26) in females, and 1.0, 1.33 (0.82-2.17), 1.60 (0.96-2.66), and 2.03 (1.21-3.40) in males. However, after adjustment for waist circumference, there were no significant differences in the ORs among the SUA quartile groups in females and males (both, p=NS). The Pearson's correlation coefficients for the relationship between SUA levels and heart-femoral (hf) PWVs or brachial-ankle (ba) PWVs were not significant in females and males (r=0.054 and r=0.015, respectively, in females; r=-0.036 and r=-0.015, respectively, in males; all, p=NS). Conclusion An elevated SUA level is associated with abdominal obesity among the MS components, but the SUA level is not associated with PWV in females or males.

Lim, Ji Hyon; Kim, Yong-Seok; Na, Sang-Hoon; Rhee, Moo-Yong; Lee, Myoung-Mook

2010-01-01

180

Urea biosensor for hemodialysis monitoring  

DOEpatents

This research discloses an electrochemical sensor capable of detecting and quantifying urea in fluids resulting from hemodialysis procedures. The sensor is based upon measurement of the pH change produced in an aqueous environment by the products of the enzyme-catalyzed hydrolysis of urea. The sensor may be fabricated using methods amenable to mass fabrication, resulting in low-cost sensors and thus providing the potential for disposable use. In a typical application, the sensor could be used in treatment centers, in conjunction with an appropriate electronics/computer system, in order to determine the hemodialysis endpoint. The sensor can also be utilized to allow at-home testing to determine if dialysis was necessary. Such a home monitor is similar, in principle, to devices used for blood glucose testing by diabetics, and would require a blood droplet sample by using a finger prick. 9 figs.

Glass, R.S.

1999-01-12

181

Urea biosensor for hemodialysis monitoring  

DOEpatents

An electrochemical sensor capable of detecting and quantifying urea in fluids resulting from hemodialysis procedures. The sensor is based upon measurement of the pH change produced in an aqueous environment by the products of the enzyme-catalyzed hydrolysis of urea. The sensor may be fabricated using methods amenable to mass fabrication, resulting in low-cost sensors and thus providing the potential for disposable use. In a typical application, the sensor could be used in treatment centers, in conjunction with an appropriate electronics/computer system, in order to determine the hemodialysis endpoint. The sensor can also be utilized to allow at-home testing to determine if dialysis was necessary. Such a home monitor is similar, in principle, to devices used for blood glucose testing by diabetics, and would require a blood droplet sample by using a finger prick.

Glass, Robert S. (Livermore, CA) [Livermore, CA

1999-01-01

182

Uric Acid and Dementia in Community-Dwelling Older Persons  

Microsoft Academic Search

Background: The biological action of uric acid (UA) in humans is controversial. UA is considered an antioxidant compound, but preclinical evidence suggests a proinflammatory action. Epidemiological studies found that hyperuricemia is associated with conditions leading to dementia. Our aim is to investigate the relationship between UA levels and dementia in older persons. Methods: Cross-sectional study performed in 1,016 community-dwelling older

Carmelinda Ruggiero; Antonio Cherubini; Fulvio Lauretani; Stefania Bandinelli; Marcello Maggio; Angelo Di Iorio; Giovanni Zuliani; Charalampos Dragonas; Umberto Senin; Luigi Ferrucci

2009-01-01

183

Chronic hyperuricemia, uric acid deposit and cardiovascular risk.  

PubMed

Hyperuricemia is commonly associated with traditional risk factors such as dysglicemia, dyslipidemia, central obesity and abnormal blood pressure, i.e. the metabolic syndrome. Concordantly, recent studies have revived the controversy over the role of circulating uric acid, hyperuricemia, and gout as an independent prognostic factor for cardiovascular morbidity and mortality. In this regard, different studies also evaluated the possible role of xanthine inhibitors in inducing blood pressure reduction, increment in flow-mediated dilation, and improved cardiovascular prognosis in various patient settings. The vast majority of these studies have been conducted with either allopurinol or its active metabolite oxypurinol, i.e. two purine-like non-selective inhibitors of xanthine oxidase. More recently, the role of uric acid as a risk factor for cardiovascular disease and the possible protective role exerted by reduction of hyperuricemia to normal level have been evaluated by the use of febuxostat, a selective, non purine-like xanthine oxidase inhibitor. In this review, we will report current evidence on hyperuricemia in cardiovascular disease. The value of uric acid as a biomarker and as a potential therapeutic target for tailored old and novel "cardiometabolic" treatments will be also discussed. PMID:23173592

Grassi, Davide; Ferri, Livia; Desideri, Giovambattista; Di Giosia, Paolo; Cheli, Paola; Del Pinto, Rita; Properzi, Giuliana; Ferri, Claudio

2013-01-01

184

Chronic Hyperuricemia, Uric Acid Deposit and Cardiovascular Risk  

PubMed Central

Hyperuricemia is commonly associated with traditional risk factors such as dysglicemia, dyslipidemia, central obesity and abnormal blood pressure, i.e. the metabolic syndrome. Concordantly, recent studies have revived the controversy over the role of circulating uric acid, hyperuricemia, and gout as an independent prognostic factor for cardiovascular morbidity and mortality. In this regard, different studies also evaluated the possible role of xanthine inhibitors in inducing blood pressure reduction, increment in flow-mediated dilation, and improved cardiovascular prognosis in various patient settings. The vast majority of these studies have been conducted with either allopurinol or its active metabolite oxypurinol, i.e. two purine-like non-selective inhibitors of xanthine oxidase. More recently, the role of uric acid as a risk factor for cardiovascular disease and the possible protective role exerted by reduction of hyperuricemia to normal level have been evaluated by the use of febuxostat, a selective, non purine-like xanthine oxidase inhibitor. In this review, we will report current evidence on hyperuricemia in cardiovascular disease. The value of uric acid as a biomarker and as a potential therapeutic target for tailored old and novel “cardiometabolic” treatments will be also discussed.

Grassi, Davide; Ferri, Livia; Desideri, Giovambattista; Giosia, Paolo Di; Cheli, Paola; Pinto, Rita Del; Properzi, Giuliana; Ferri, Claudio

2013-01-01

185

Uric Acid as a Target of Therapy in CKD  

PubMed Central

The prevalence of chronic kidney disease (CKD) has risen and will continue to rise in the United States and worldwide. This is alarming considering that CKD remains an irreversible condition and patients who progress to chronic kidney failure suffer reduced quality of life and high mortality rates. As such, it is imperative to identify modifiable risk factors to develop strategies to slow CKD progression. One such factor is hyperuricemia. Recent observational studies have associated hyperuricemia with kidney disease. In addition, hyperuricemia is largely prevalent in patients with CKD. Data from experimental studies have revealed several potential mechanisms by which hyperuricemia may contribute to the development and progression of CKD. In this manuscript we offer a critical review of the experimental evidence linking hyperuricemia to CKD, we highlight the gaps in our knowledge on the topic as it stands today, and we review the observational and interventional studies that have examined the potential nephro-protective effect of lowering uric acid in CKD patients . While uric acid may also be linked to cardiovascular disease and mortality in patients with CKD, this review will focus only on uric acid as a potential therapeutic target to prevent kidney disease onset and progression.

Jalal, Diana I.; Chonchol, Michel; Chen, Wei; Targher, Giovanni

2012-01-01

186

Creatinine biomaterial thin films grown by laser techniques.  

PubMed

Creatinine thin films were synthesised by matrix assisted pulsed laser deposition (PLD) techniques for enzyme-based biosensor applications. An UV KrF* (lambda=248 nm, tau approximately 10 ns) excimer laser source was used for the irradiation of the targets at incident fluence values in the 0.3-0.5 J/cm2 range. For the matrix assisted PLD the targets consisted on a frozen composite obtained by dissolving the biomaterials in distilled water. The surface morphology, chemical composition and structure of the obtained biomaterial thin films were investigated by scanning electron microscopy, Fourier transform infrared spectroscopy, and electron dispersive X-ray spectroscopy as a function of the target preparation procedure and incident laser fluence. PMID:17914621

György, E; Axente, E; Mihailescu, I N; Predoi, D; Ciuca, S; Neamtu, J

2008-03-01

187

Relationship between serum uric acid levels and ventricular function in patients with idiopathic pulmonary hypertension  

PubMed Central

OBJECTIVE: To investigate the relationship between serum uric acid levels and pulmonary hypertension in patients with idiopathic pulmonary artery hypertension (IPAH). METHODS: Serum uric acid levels were measured in 86 patients (mean [± SD] age 35.2±12.3 years; 36 men) with IPAH. Pulmonary arterial pressure and ventricular function were assessed using echocardiography. Serum uric acid levels were also measured in 40 healthy subjects (35.9±11.6 years of age; 15 men). RESULTS: Serum uric acid levels in IPAH patients were higher compared with control subjects (405±130 ?mol/L versus 344±96 ?mol/L; P<0.05). Fifty-two (60.4%) of the 86 patients with IPAH had elevated serum uric acid levels. The pulmonary systolic pressure and mean pulmonary pressure in the high uric acid group were higher than in the normal uric acid group (P<0.05). The left and right ventricular ejection fractions were lower in the high uric acid group compared with the normal uric acid group (P<0.05). Serum uric acid levels were correlated with the mean pulmonary arterial pressure (r=0.387; P<0.01) and New York Heart Association class (r=0.41; P<0.01). There was also an inverse correlation between uric acid levels and the left (r=?0.550; P<0.01) and right ventricular ejection fractions (r=?0.481; P<0.05). CONCLUSION: Serum uric acid levels are associated with IPAH severity and the severity of ventricular dysfunction.

Zhang, Chun-Yan; Ma, Long-Le; Wang, Le-Xin

2013-01-01

188

Testosterone replacement elevates the serum uric acid levels in patients with female to male gender identity disorder.  

PubMed

Gender identity disorder (GID) results from a disagreement between a person's biological sex and the gender to which he or she identifies. With respect to the treatment of female to male GID, testosterone replacement therapy (TRT) is available. The uric acid (UA) level can be influenced by testosterone; however, the early effects and dose-dependency of TRT on the serum UA concentration have not been evaluated in this population. We herein conducted a dose-response analysis of TRT in 160 patients with female to male GID. The TRT consisted of three treatment groups who received intramuscular injections of testosterone enanthate: 125 mg every two weeks, 250 mg every three weeks and 250 mg every two weeks. Consequently, serum UA elevation was observed after three months of TRT and there was a tendency toward testosterone dose-dependency. The onset of hyperuricemia was more prevalent in the group who received the higher dose. We also demonstrated a positive correlation between increased levels of serum UA and serum creatinine. Since the level of serum creatinine represents an individual's muscle volume and the muscle is a major source of purine, which induces UA upregulation, the serum UA elevation observed during TRT is at least partially attributed to an increase in muscle mass. This is the first study showing an association between serum UA elevation and a TRT-induced increase in muscle mass. The current study provides important information regarding TRT for the follow-up and management of the serum UA levels in GID patients. PMID:24047564

Kurahashi, Hiroaki; Watanabe, Masami; Sugimoto, Morito; Ariyoshi, Yuichi; Mahmood, Sabina; Araki, Motoo; Ishii, Kazushi; Nasu, Yasutomo; Nagai, Atsushi; Kumon, Hiromi

2013-01-01

189

Pro-inflammatory effects of uric acid in the gastrointestinal tract  

PubMed Central

Uric acid can be generated in the gastrointestinal (GI) tract from the breakdown of nucleotides ingested in the diet or from purines released from host cells as a result of pathogen-induced cell damage. Xanthine oxidase (XO) is the enzyme that converts hypoxanthine or xanthine into uric acid, a reaction that also generates hydrogen peroxide. It has been assumed that the product of XO responsible for the pro-inflammatory effects of this enzyme is hydrogen peroxide. Recent literature on uric acid, however, has indicated that uric acid itself may have biological effects. We tested whether uric acid itself has detectable pro-inflammatory effects using an in vivo model using ligated rabbit intestinal segments (“loops”) as well as in vitro assays using cultured cells. Addition of exogenous uric acid increased the influx of heterophils into rabbit intestinal loops, as measured by myeloperoxidase activity. In addition, white blood cells adhered avidly to uric acid crystals, forming large aggregates of cells. Uric acid acts as a leukocyte chemoattractant in the GI tract. The role of uric acid in enteric infections and in non-infectious disorders of the GI tract deserves more attention.

Crane, John K.; Mongiardo, Krystin M.

2014-01-01

190

Two-stage magnetic orientation of uric acid crystals as gout initiators  

NASA Astrophysics Data System (ADS)

The present study focuses on the magnetic behavior of uric acid crystals, which are responsible for gout. Under a sub-Tesla (T)-level magnetic field, rotational motion of the crystals, which were caused by diamagnetic torque, was observed. We used horizontal magnetic fields with a maximum magnitude of 500 mT generated by an electromagnet to observe the magnetic orientation of the uric acid microcrystals by a microscope. The uric acid crystals showed a perpendicular magnetic field orientation with a minimum threshold of 130 mT. We speculate that the distinct diamagnetic anisotropy in the uric acid crystals resulted in their rotational responses.

Takeuchi, Y.; Miyashita, Y.; Mizukawa, Y.; Iwasaka, M.

2014-01-01

191

Analysis of serum creatinine using an immobilized enzyme nylon tube reactor incorporating a four-enzyme system  

Microsoft Academic Search

Index Entries: Serum creatinine, immobilized enzyme analysis of; creatinine, immobilized enzyme analysis of; immobilized enzyme analysis, of serum creatininc; nylon tube reactor, in immobilized enzyme analysis of creatinine. Ginman et al. (l) recently described the use of a single nylon reactor with four immobilized enzymes for the analysis of creatinine in urine. The tube was incorporated in a continuous flow

Ron Ginman; Janet S. Colliss

1983-01-01

192

Continuous monitoring of urea levels during hemodialysis.  

PubMed

An ammonium ion-specific electrode system is evaluated for analysis of blood urea nitrogen from serum, plasma ultrafiltrate, or hemodialyzer dialysate fluid. The electrode shows a high sensitivity over clinically useful concentration ranges. Free serum ammonia, volatile amines, or urea ammonia after hydrolysis can be measured. In a double blind study excellent correlation was found for 187 blood urea nitrogen samples measured with the electrode with standard auto-analyzer techniques. Continuous monitoring of urea in dialysate fluid is described. Urea clearances were measured from dialysate effluent from an in vitro dialysis using conventional equipment. These values show excellent correlation to those from stnadard analysis methods. A continuous urea sensor for on-line hemodialysis application which can provide quantification of therapy is described. PMID:357303

Klein, E; Montalvo, J G; Wawro, R; Holland, F F; Lebeouf, A

1978-05-01

193

Use of the Albumin\\/Creatinine Ratio to Detect Microalbuminuria: Implications of Sex and Race  

Microsoft Academic Search

The recommended albumin (g)\\/creatinine (mg) ra- tio (ACR) (30 g\\/mg) to detect microalbuminuria does not account for sex or racial differences in creatinine excretion. In a nationally representative sample of subjects, the distribution of urine albumin and creatinine concentrations was examined by using one ACR value (30 g\\/mg) and sex-specific cut- points (17 g\\/mg in men and 25 g\\/mg in

HOLLY J. MATTIX; CHI-YUAN HSU; SHIMON SHAYKEVICH; GARY CURHAN

194

Conductometric uric acid and urea biosensor prepared from electroconductive polyaniline–poly( n-butyl methacrylate) composites  

Microsoft Academic Search

Polyaniline–poly(n-butyl methacrylate) (PAn–PBMA) composite films were obtained by casting. The homogeneous films were prepared with poly(vinyl methyl ether) (PVME) and poly(vinyl ethyl ether) (PVEE) as dispersants, and the electric conductivity, mechanical properties and morphology were studied. The PAn integration to the composite is better when PVEE is used as dispersant, but the conductivity is higher when PVME is used. The

M. M. Castillo-Ortega; D. E. Rodriguez; J. C. Encinas; M. Plascencia; F. A. Méndez-Velarde; R. Olayo

2002-01-01

195

Chemical Structure and Curing Behavior of Phenol–Urea–Formaldehyde Cocondensed Resins of High Urea Content  

Microsoft Academic Search

Phenol–urea–formaldehyde cocondensed (PUF) resins of high urea content were prepared by adding different forms of urea to the reaction system. The structure, curing behavior, and water resistance of the PUF resins were investigated, and their relations were also discussed by liquid C nuclear magnetic resonance (NMR) and different scanning calorimetry (DSC). The liquid C-NMR analysis showed that urea added in

Dongbin Fan; Jianzhang Li; Jianmin Chang; Jinsheng Gou; Jinxue Jiang

2009-01-01

196

Spectroscopic characterization of urea aqueous solutions: experimental phase diagram of the urea-water binary system.  

PubMed

Raman spectroscopy was used to analyze mixtures of urea and water in order to identify the influence of the urea concentration on the solution's freezing point. Our approach consisted in the analysis of urea aqueous solutions and the determination of their phase transitions at low temperatures. Hence, Raman spectra of these solutions were acquired in a -30 to 10 °C temperature range. This enabled us to build the experimental phase diagram of the urea-water binary system. PMID:24067578

Durickovic, Ivana; Thiébaud, Laura; Bourson, Patrice; Kauffmann, Thomas; Marchetti, Mario

2013-10-01

197

Nitrogen and urea metabolism during continuous ambulatory peritoneal dialysis  

Microsoft Academic Search

Nitrogen and urea metabolism during continuous ambulatory peritoneal dialysis. During continuous ambulatory peritoneal dialysis (CAPD), concentrations of serum urea nitrogen (SUN) have been reported that are lower than what would be predicted from estimated dietary protein intake and the calculated urea clearance by dialysis. Net urea generation (urea nitrogen appearance) and losses of various nitrogenous constituents were measured during 12

Michael J Blumenkrantz; Joel D Kopple; John K Moran; Gerald P Grodstein; Jack W Coburn

1981-01-01

198

Metabolic Syndrome, Alcohol Consumption and Genetic Factors Are Associated with Serum Uric Acid Concentration  

PubMed Central

Objective Uric acid is the end product of purine metabolism in humans, and increased serum uric acid concentrations lead to gout. The objective of the current study was to identify factors that are independently associated with serum uric acid concentrations in a cohort of Czech control individuals. Methods The cohort consisted of 589 healthy subjects aged 18–65 years. We studied the associations between the serum uric acid concentration and the following: (i) demographic, anthropometric and other variables previously reported to be associated with serum uric acid concentrations; (ii) the presence of metabolic syndrome and the levels of metabolic syndrome components; and (iii) selected genetic variants of the MTHFR (c.665C>T, c.1286A>C), SLC2A9 (c.844G>A, c.881G>A) and ABCG2 genes (c.421C>A). A backward model selection procedure was used to build two multiple linear regression models; in the second model, the number of metabolic syndrome criteria that were met replaced the metabolic syndrome-related variables. Results The models had coefficients of determination of 0.59 and 0.53. The serum uric acid concentration strongly correlated with conventional determinants including male sex, and with metabolic syndrome-related variables. In the simplified second model, the serum uric acid concentration positively correlated with the number of metabolic syndrome criteria that were met, and this model retained the explanatory power of the first model. Moderate wine drinking did not increase serum uric acid concentrations, and the urate transporter ABCG2, unlike MTHFR, was a genetic determinant of serum uric acid concentrations. Conclusion Metabolic syndrome, moderate wine drinking and the c.421C>A variant in the ABCG gene are independently associated with the serum uric acid concentration. Our model indicates that uric acid should be clinically monitored in persons with metabolic syndrome.

Stiburkova, Blanka; Pavlikova, Marketa; Sokolova, Jitka; Kozich, Viktor

2014-01-01

199

Uric acid as one of the important factors in multifactorial disorders--facts and controversies.  

PubMed

With considering serum concentration of the uric acid in humans we are observing hyperuricemia and possible gout development. Many epidemiological studies have shown the relationship between the uric acid and different disorders such are obesity, metabolic syndrome, hypertension and coronary artery disease. Clinicians and investigators recognized serum uric acid concentration as very important diagnostic and prognostic factor of many multifactorial disorders. This review presented few clinical conditions which are not directly related to uric acid, but the concentrations of uric acid might have a great impact in observing, monitoring, prognosis and therapy of such disorders. Uric acid is recognized as a marker of oxidative stress. Production of the uric acid includes enzyme xanthine oxidase which is involved in producing of radical-oxigen species (ROS). As by-products ROS have a significant role in the increased vascular oxidative stress and might be involved in atherogenesis. Uric acid may inhibit endothelial function by inhibition of nitric oxide-function under conditions of oxidative stress. Down regulation of nitric oxide and induction of endothelial dysfunction might also be involved in pathogenesis of hypertension. The most important and well evidenced is possible predictive role of uric acid in predicting short-term outcome (mortality) in acute myocardial infarction (AMI) patients and stroke. Nephrolithiasis of uric acid origin is significantly more common among patients with the metabolic syndrome and obesity. On contrary to this, uric acid also acts is an "antioxidant", a free radical scavenger and a chelator of transitional metal ions which are converted to poorly reactive forms. PMID:22384520

Pasalic, Daria; Marinkovic, Natalija; Feher-Turkovic, Lana

2012-01-01

200

Characterization of the Complete Uric Acid Degradation Pathway in the Fungal Pathogen Cryptococcus neoformans  

PubMed Central

Degradation of purines to uric acid is generally conserved among organisms, however, the end product of uric acid degradation varies from species to species depending on the presence of active catabolic enzymes. In humans, most higher primates and birds, the urate oxidase gene is non-functional and hence uric acid is not further broken down. Uric acid in human blood plasma serves as an antioxidant and an immune enhancer; conversely, excessive amounts cause the common affliction gout. In contrast, uric acid is completely degraded to ammonia in most fungi. Currently, relatively little is known about uric acid catabolism in the fungal pathogen Cryptococcus neoformans even though this yeast is commonly isolated from uric acid-rich pigeon guano. In addition, uric acid utilization enhances the production of the cryptococcal virulence factors capsule and urease, and may potentially modulate the host immune response during infection. Based on these important observations, we employed both Agrobacterium-mediated insertional mutagenesis and bioinformatics to predict all the uric acid catabolic enzyme-encoding genes in the H99 genome. The candidate C. neoformans uric acid catabolic genes identified were named: URO1 (urate oxidase), URO2 (HIU hydrolase), URO3 (OHCU decarboxylase), DAL1 (allantoinase), DAL2,3,3 (allantoicase-ureidoglycolate hydrolase fusion protein), and URE1 (urease). All six ORFs were then deleted via homologous recombination; assaying of the deletion mutants' ability to assimilate uric acid and its pathway intermediates as the sole nitrogen source validated their enzymatic functions. While Uro1, Uro2, Uro3, Dal1 and Dal2,3,3 were demonstrated to be dispensable for virulence, the significance of using a modified animal model system of cryptococcosis for improved mimicking of human pathogenicity is discussed.

Lee, I. Russel; Yang, Liting; Sebetso, Gaseene; Allen, Rebecca; Doan, Thi H. N.; Blundell, Ross; Lui, Edmund Y. L.; Morrow, Carl A.; Fraser, James A.

2013-01-01

201

The amylase-creatinine clearance ratio following cardiopulmonary bypass.  

PubMed

The incidence of unexplained pancreatitis in patients dying after cardiac operations has been recorded as 16%, with evidence to implicate ischemia in the pathogenesis of the pancreatitis. Increased amylase--to--creatinine clearance ratios (ACCR), suggesting pancreatic dysfunction, have been reported in patients following nonpulsatile cardiopulmonary bypass (CPB). Pulsatile CPB is increasingly recognized to be a more physiological form of perfusion, particularly with respect to capillary blood flow. In this study the ACCR has been determined before, during, and after cardiac operations performed with both nonpulsatile and pulsatile CPB. Twenty patients undergoing elective cardiac operations were studied. Ten patients had nonpulsatile CPB (nonpulsatile group) and 10 had pulsatile CPB (pulsatile group). The two groups were comparable as regards perioperative variables and perfusion parameters. In both groups the ACCR was estimated preoperatively, on three occasions during the operation, and daily on the first 5 postoperative days. A significant elevation in ACCR was observed in nine of 10 patients in the nonpulsatile group but in only one of 10 patients in the pulsatile group (p less than 0.001). The significant improvement of ACCR stability following pulsatile CPB may indicate that this form of perfusion will reduce the risk of pancreatitis following cardiac operations performed with CPB. PMID:6166815

Murray, W R; Mittra, S; Mittra, D; Roberts, L B; Taylor, K M

1981-08-01

202

Precipitation diagrams and solubility of uric acid dihydrate  

NASA Astrophysics Data System (ADS)

The solubility of uric acid dihydrate (UA·2H 2O) and the precipitation of UA·2H 2O and anhydrous uric acid (UA) from solutions containing sodium hydroxide and hydrochloric acid have been investigated. For the solubility studies, crystals of pure UA·2H 2O were prepared and equilibrated with water and with solutions of HCl or NaOH for 60 min or 20 h, respectively. The equilibrium pH (pH = 2-6.25) and uric acid concentration were determined. For the precipitation experiments, commercial UA was dissolved in NaOH in a 1:1.1 molar ratio and UA·2H 2O and/or UA were precipitated with hydrochloric acid. The precipitates and/or supernatants were examined 24 h after sample preparation. The results are represented in the form of tables, precipitation diagrams and "chemical potential" diagrams. Solubility measurements with 60 min equilibration times yielded the solubility products of UA·2H 2O, K sp(298 K) = (0.926 ± 0.025) × 10 -9mol2dm-6 and K sp(310 K) = (2.25 ± 0.05) × 10 -9mol2dm-6 and the first dissociation constants of uric acid, K 1(298 K) = (2.45 ± 0.07) × 10 -6moldm-3 and K 1(310 K) = (3.63 ± 0.08) × 10 -6moldm-3. Precipitation diagrams show that under the given experimental conditions, at 298 K, UA·2H 2O is stable for 24 h while at 310 K this was true only for precipitates formed from solutions of high supersaturations. At lower supersaturations, mixtures of UA·2H 2O and UA formed. Consequently, while the Ksp value determined from precipitation data obtained at 298 K (K sp = 1.04 × 10 -9mol2dm-6) was consistent with the respective solubility product, the 310 K precipitation boundary yielded an ion activity product, AP, the value of which fulfills the conditions Ksp(UA) < AP < Ksp (UA·2H 2O). Similar ion activity products were obtained from solubility measurements in pure water at 20 h equilibration time.

Babi?-Ivan?i?, V.; Füredi-Milhofer, H.; Brown, W. E.; Gregory, T. M.

1987-07-01

203

Role of uric acid in hypertension, renal disease, and metabolic syndrome  

Microsoft Academic Search

? ABSTRACT Hyperuricemia has long been known to be associated with cardiovascular disease, and it is particularly common in people with hypertension, metabolic syndrome, or kidney disease. Most authorities have viewed elevated uric acid as a secondary phenomenon that is either innocuous or perhaps even beneficial, since uric acid can be an antioxidant. However, recent experiments have challenged this viewpoint.

MARCELO HEINIG; RICHARD J. JOHNSON

2006-01-01

204

Uric Acid Puzzle: Dual Role as Anti-oxidantand Pro-oxidant  

PubMed Central

Hyperuricemia is known to be associated with the presence of cardiovascular and metabolic syndrome and with the development of incipient kidney disease and an accelerated renal progression. However, an elevated uric acid level was not generally regarded as a true etiology or mediator, but an indicator of these diseases. Uric acid has recently regained the clinical interest and popularity based on emerging data suggesting the causative role of hyperuricemia in cardiovascular and renal disease. Experimental data demonstrates oxidative stress is one of the earliest phenomena observed in vascular, renal, liver cells and adipocytes exposed to uric acid. Since uric acid is one of the major antioxidants of plasma acting as a free radical scavenger and a chelator of transitional metal ion, uric acid-induced oxidative stress seems paradoxical. Data regarding the clinical implication of hyperuricemia is even more confusing, which defines hyperuricemia as a useless parameter to be eliminated from routine follow-up or a major risk factor to be therapeutic target. With a review of experimental and epidemiologic data, the presence of molecular switch to regulate the role of uric acid as anti- or pro-oxidant in different compartment of our body is suggested, which may shed light on understanding the paradoxical role of uric acid and solving the "uric acid debate".

Kang, Duk-Hee

2014-01-01

205

Effect of insulin on renal sodium and uric acid handling in essential hypertension  

Microsoft Academic Search

In normal subjects, insulin decreases the urinary excretion of sodium, potassium, and uric acid. We tested whether these renal effects of insulin are altered in insulin resistant hypertension. In 37 patients with essential hypertension, we measured the changes in urinary excretion of sodium, potassium, and uric acid in response to physiological euglycemic hyperinsulinemia (by using the insulin clamp technique at

Elza Muscelli; Andrea Natali; Stefano Bianchi; Roberto Bigazzi; Alfredo Quiñones Galvan; Anna Maria Sironi; Silvia Frascerra; Demetrio Ciociaro; Ele Ferrannini; E. Ferrannini

1996-01-01

206

Serum uric acid as an index of impaired oxidative metabolism in chronic heart failure  

Microsoft Academic Search

Background Elevated serum uric acid concentrations have been observed in clinical conditions associated with hypoxia. Since chronic heart failure is a state of impaired oxidative metabolism, we sought to determine whether serum uric acid concentrations correlate with measures of functional capacity and disease severity. Methods Fifty nine patients with a diagnosis of chronic heart failure due to coronary heart disease

F. Leyva; S. Anker; J. W. Swan; T.-P. Chua; J. C. Stevensonf; A. J. S. Coats

207

Uric Acid, a Natural Scavenger of Peroxynitrite, in Experimental Allergic Encephalomyelitis and Multiple Sclerosis  

Microsoft Academic Search

Uric acid, the naturally occurring product of purine metabolism, is a strong peroxynitrite scavenger, as demonstrated by the capacity to bind peroxynitrite but not nitric oxide (NO) produced by lipopolysaccharide-stimulated cells of a mouse monocyte line. In this study, we used uric acid to treat experimental allergic encephalomyelitis (EAE) in the PLSJL strain of mice, which develop a chronic form

D. C. Hooper; S. Spitsin; R. B. Kean; J. M. Champion; G. M. Dickson; I. Chaudhry; H. Koprowski

1998-01-01

208

Uric acid secretion from adipose tissue and its increase in obesity.  

PubMed

Obesity is often accompanied by hyperuricemia. However, purine metabolism in various tissues, especially regarding uric acid production, has not been fully elucidated. Here we report, using mouse models, that adipose tissue could produce and secrete uric acid through xanthine oxidoreductase (XOR) and that the production was enhanced in obesity. Plasma uric acid was elevated in obese mice and attenuated by administration of the XOR inhibitor febuxostat. Adipose tissue was one of major organs that had abundant expression and activities of XOR, and adipose tissues in obese mice had higher XOR activities than those in control mice. 3T3-L1 and mouse primary mature adipocytes produced and secreted uric acid into culture medium. The secretion was inhibited by febuxostat in a dose-dependent manner or by gene knockdown of XOR. Surgical ischemia in adipose tissue increased local uric acid production and secretion via XOR, with a subsequent increase in circulating uric acid levels. Uric acid secretion from whole adipose tissue was increased in obese mice, and uric acid secretion from 3T3-L1 adipocytes was increased under hypoxia. Our results suggest that purine catabolism in adipose tissue could be enhanced in obesity. PMID:23913681

Tsushima, Yu; Nishizawa, Hitoshi; Tochino, Yoshihiro; Nakatsuji, Hideaki; Sekimoto, Ryohei; Nagao, Hirofumi; Shirakura, Takashi; Kato, Kenta; Imaizumi, Keiichiro; Takahashi, Hiroyuki; Tamura, Mizuho; Maeda, Norikazu; Funahashi, Tohru; Shimomura, Iichiro

2013-09-20

209

A comparison of the metabolic profiles of diabetic and non-diabetic uric acid stone formers  

PubMed Central

Introduction: The aim of this study was to compare the metabolic profiles of diabetic and non-diabetic patients with uric acid stones to understand whether preventive strategies should be tailored to reflect different causative factors. Methods: The results of the metabolic evaluation of patients with uric acid stones identified prospectively from the Metabolic Stone Clinic at St. Joseph’s Hospital, London, Canada were reviewed. Information included patients’ clinical histories, 24 hour urine collections, blood chemistry and stone analysis. Results: Complete data were obtained from 68 patients with uric acid stones. Twenty-two patients had diabetes. There were no statistically significant differences in mean age, body mass index, or history of gout. Among diabetics, pure uric acid stones were identified in 14 patients (63%) and mixed uric acid in 8 (36%). Pure uric acid stones were more common in the diabetic cohort (63% vs. 46%, p = 0.16). Urine pH, serum and urine uric acid levels and 24-hour urine volumes were similar in both groups. The diabetic group had an increased average oxalate excretion (424 ?mol/d vs. 324 ?mol/d, p = 0.003). Conclusion: The exact etiological basis for the higher oxalate excretion in diabetic uric acid stone formers is unclear. Whether this is a metabolic feature of diabetes, due to dietary indiscretion or the iatrogenic consequence of dietary advice requires further investigation.

Fernandez, Alfonso; Fuller, Andrew; Al-Bareeq, Reem; Nott, Linda; Razvi, Hassan

2013-01-01

210

Effects of Marine Corps Officer Candidate School Training on Serum Uric Acid Levels.  

National Technical Information Service (NTIS)

Serum uric acid levels were measured in successful Marine Corps Officer Candidate School students before and after the 12 weeks' intensive physical training. There was a significant fall in the serum uric acid level of 52 subjects from 6.01 mg percent to ...

L. H. Cronau P. J. Rasch J. W. Hamby H. J. Burns

1970-01-01

211

Postnatal Development of the Urine Cortisol\\/Creatinine Ratio in the Dog  

Microsoft Academic Search

Vostatková K., P. Štarha, P. Kaláb, J. blahová, E. baranyiová: Postnatal Development of the Urine Cortisol\\/Creatinine ratio in the Dog. acta Vet. brno 77, 2008: 509-513. the objective of this experiment was to study the age changes of cortisol to creatinine ratio in urine of growing puppies between birth and the age of 8 weeks. beagle puppies (n = 14)

K. Vostatková; P. Štarha; P. Kaláb; J. Blahová; E. Baranyiová

2008-01-01

212

Albumin:Creatinine Ratio – A Flawed Measure? The Merits of Estimated Albuminuria Reporting  

Microsoft Academic Search

Current guidelines illogically recommend that a different approach is taken to the correction for creatinine generation rate when estimating glomerular filtration rate (GFR) and when interpreting urine albumin:creatinine ratio (ACR). Age, gender and race are routinely used to adjust for predicted muscle mass in GFR estimation, even though estimated GFR is expressed per unit body surface area. Conversely, ACR is

Timothy J. Ellam

2011-01-01

213

Normal Values for Random Urinary Calcium to Creatinine Ratio in Iranian Children  

Microsoft Academic Search

Objective: Due to worldwide variations, reference values of urinary calcium to creatinine ratio in pediatric population are not yet well established. To determine normal values for urinary calcium to creatinine ratio and its relation to urinary sodium or potassium, a descriptive (correlation type) study was conducted in 7 to 12 years old healthy children in Urmia, Iran. Methods: Primary school

Ahmadali Nikibakhsh; Pediatric Nephrologist; Abolhassan Seyedzadeh; Hashem Mahmoodzadeh; Zahra Yekta; Mohammadtaghi Zadieh; Mohammad Karamyar; Pediatric Infectious; Diseases Specialist; Ahad Ghozavi

214

Certification of Creatinine in a Human Serum Reference Material by GC-MS and LCMS  

Microsoft Academic Search

Background: To meet recommendations given by the Laboratory Working Group of the National Kidney Disease Education Program (NKDEP) for improving serum creatinine measurements, NIST developed stan- dard reference material (SRM) 967 Creatinine in Frozen Human Serum. SRM 967 is intended for use by labora- tories and in vitro diagnostic equipment manufacturers for the calibration and evaluation of routine clinical methods.

Nathan G. Dodder; Susan S.-C. Tai; Lorna T. Sniegoski; Nien F. Zhang; Michael J. Welch

215

Automated urinalysis technique determines concentration of creatine and creatinine by colorimetry  

NASA Technical Reports Server (NTRS)

Continuous urinalysis technique is useful in the study of muscle wastage in primates. Creatinine concentration in urine is determined in an aliquot mixture by a color reaction. Creatine is determined in a second aliquot by converting it to creatinine and measuring the difference in color intensity between the two aliquots.

Rho, J. H.

1967-01-01

216

When laboratories report estimated glomerular filtration rates in addition to serum creatinines, nephrology consults increase  

Microsoft Academic Search

Serum creatinine alone can be difficult to interpret as a measure of kidney function such that chronic kidney disease might be under-recognized in the general population. In the province of Ontario, Canada, all outpatient laboratories now report estimated glomerular filtration rate (eGFR) in addition to serum creatinine. To determine the impact of this reporting on clinical practice, we linked health

Arsh K Jain; Ian McLeod; Cindy Huo; Meaghan S Cuerden; Ayub Akbari; Marcello Tonelli; Carl van Walraven; Rob R Quinn; Brenda Hemmelgarn; Matt J Oliver; Ping Li; Amit X Garg

2009-01-01

217

Reliability of urinary creatinine as a parameter used to adjust values of urinary biological indicators  

Microsoft Academic Search

The values of biological indicators used in biological monitoring are usually determined on spot samples of urine. In order to reduce the variations due to dilution, it is common practice to correct the values according to reference parameters, such as urinary creatinine concentration and specific gravity. The aim of the present study was to verify whether creatinine possesses the necessary

L. Alessio; A. Dell'Orto; F. Toffoletto; I. Ghezzi

1985-01-01

218

Worsening renal function: What is a clinically meaningful change in creatinine during hospitalization with heart failure?  

Microsoft Academic Search

Introduction: Worsening renal function during hospitalization for heart failure, defined as elevation in creatinine during admission, predicts adverse outcomes. Prior studies define worsening renal function using various creatinine elevations, but the relative value of definitions is unknown. Methods and Results: In a prospective cohort of 412 patients hospitalized for heart failure, we compared a spectrum of worsening renal function definitions

Grace L. Smith; Viola Vaccarino; Mikhail Kosiborod; Judith H. Lichtman; Susan Cheng; Suzanne G. Watnick; Harlan M. Krumholz

2003-01-01

219

Creatinine generation rate and lean body mass: A critical analysis in peritoneal dialysis patients  

Microsoft Academic Search

Creatinine generation rate and lean body mass: A critical analysis in peritoneal dialysis patients. Calculation of creatinine generation rate (CGR) has been reintroduced as a method to estimate lean body mass (LBM) in dialysis patients. It has also been suggested that it be used to identify noncompliance with dialysis prescription. In order to evaluate this method, LBM calculated from CGR

Ann-Cathrine Johansson; Per-Ola Attman; Börje Haraldsson

1997-01-01

220

Variability of Creatinine Measurements in Clinical Laboratories: Results from the CRIC Study  

Microsoft Academic Search

Objectives: Estimating equations using serum creatinine (SCr) are often used to assess glomerular filtration rate (GFR). Such creatinine (Cr)-based formulae may produce biased estimates of GFR when using Cr measurements that have not been calibrated to reference laboratories. In this paper, we sought to examine the degree of this variation in Cr assays in several laboratories associated with academic medical

Marshall Joffe; Chi-yuan Hsu; Harold I. Feldman; Matthew Weir; J. R. Landis; L. Lee Hamm

2010-01-01

221

Chronic progressive renal disease: Rate of change of serum creatinine concentration  

Microsoft Academic Search

Chronic progressive renal disease : Rate of change of serum concentration. The rate of change of the serum creatinine concentrations in 63 patients with chronic progressive renal disease of varied etiology was examined by linear regression analysis using the logarithm or the reciprocal of the serum creatinine concentration versus time. A single straight line was described by one or the

W Ernest Rutherford; Joan Blondin; J Philip Miller; Allen S Greenwalt; John D Vavra

1977-01-01

222

Urea Transporter Physiology Studied in Knockout Mice  

PubMed Central

In mammals, there are two types of urea transporters; urea transporter (UT)-A and UT-B. The UT-A transporters are mainly expressed in kidney epithelial cells while UT-B demonstrates a broader distribution in kidney, heart, brain, testis, urinary tract, and other tissues. Over the past few years, multiple urea transporter knockout mouse models have been generated enabling us to explore the physiological roles of the different urea transporters. In the kidney, deletion of UT-A1/UT-A3 results in polyuria and a severe urine concentrating defect, indicating that intrarenal recycling of urea plays a crucial role in the overall capacity to concentrate urine. Since UT-B has a wide tissue distribution, multiple phenotypic abnormalities have been found in UT-B null mice, such as defective urine concentration, exacerbated heart blockage with aging, depression-like behavior, and earlier male sexual maturation. This review summarizes the new insights of urea transporter functions in different organs, gleaned from studies of urea transporter knockout mice, and explores some of the potential pharmacological prospects of urea transporters.

Li, Xuechen; Chen, Guangping; Yang, Baoxue

2012-01-01

223

Extraction of urea and ammonium ion  

NASA Technical Reports Server (NTRS)

Water purification system keeps urea and ammonium ion concentration below toxic limits in recirculated water of closed loop aquatic habitat. Urea is first converted to ammonium ions and carbon dioxide by enzygmatic action. Ammonium ions are removed by ion exchange. Bioburden is controlled by filtration through 0.45 micron millipore filters.

Anselmi, R. T.; Husted, R. R.; Schulz, J. R.

1977-01-01

224

40 CFR 721.9925 - Aminoethylethylene urea methacrylamide.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Aminoethylethylene urea methacrylamide. 721.9925 Section...Substances § 721.9925 Aminoethylethylene urea methacrylamide. (a) Chemical substance...identified generically as an aminoethylethylene urea methacrylamide (PMN...

2013-07-01

225

Uric Acid: A Novel Risk Factor for Acute Kidney Injury in High-Risk Cardiac Surgery Patients?  

Microsoft Academic Search

Background: Uric acid has been reported to be a risk factor for the development of chronic kidney disease; however, no study has examined whether uric acid may confer a risk for acute kidney injury. Methods: We investigated the relation between serum uric acid and the incidence of postoperative acute kidney injury in patients undergoing high-risk cardiovascular surgery (cardiac valve and

A. Ahsan Ejaz; Thomas M. Beaver; Michiko Shimada; Puneet Sood; Vijaykumar Lingegowda; Jesse D. Schold; Tad Kim; Richard J. Johnson

2009-01-01

226

The effect of a vegetarian and different omnivorous diets on urinary risk factors for uric acid stone formation  

Microsoft Academic Search

Summary. Background: About 10–15% of all urinary stones are composed of uric acid. A high urinary uric acid excretion, a low urine volume and an acidic urinary pH value are suggested to be the most important risk factors for uric acid stone formation. Aim of the study: The effect of a vegetarian diet and different omnivorous diets on the risk

Roswitha Siener; Albrecht Hesse

2003-01-01

227

Serum uric acid as an independent predictor of mortality in patients with angiographically proven coronary artery disease  

Microsoft Academic Search

It is a matter of controversy as to whether uric acid is an independent predictor of mortality in patients with coronary artery disease (CAD) or whether it represents only an indirect marker of adverse outcome by reflecting the association between uric acid and other cardiovascular risk factors. Therefore, we studied the influence of uric acid levels on mortality in patients

Christoph Bickel; Hans J Rupprecht; Stefan Blankenberg; Gerd Rippin; Gerd Hafner; Alexander Daunhauer; Klaus-Peter Hofmann; Jürgen Meyer

2002-01-01

228

Could Uric Acid be a Modifiable Risk Factor in Subjects with Pulmonary Hypertension?  

PubMed Central

A high serum uric acid is common in subjects with pulmonary hypertension. The increase in serum uric acid may be a consequence of the local tissue ischemia and/or hypoxia, and it may also result from other factors independent of ischemia or hypoxia that occur in various forms of pulmonary hypertension. While classically viewed as a secondary phenomenon, recent studies suggest that hyperuricemia may also have a role in mediating the local vasoconstriction and vascular remodeling in the pulmonary vasculature. If uric acid does have a contributory role in pulmonary hypertension, we may see an increasing prevalence of pulmonary hypertension as hyperuricemia is common in subjects with obesity and metabolic syndrome. We propose studies to investigate the role of uric acid in pulmonary hypertension and to determine if lowering serum uric acid may have clinical benefit in this condition.

Zharikov, Sergey I; Swenson, Erik R; Lanaspa, Miguel; Block, Edward R; Patel, Jawaharlal M; Johnson, Richard J

2010-01-01

229

Uric acid and xanthine oxidase: future therapeutic targets in the prevention of cardiovascular disease?  

PubMed Central

Serum uric acid may be an independent risk factor for cardiovascular disease. This review examines this association, potential mechanisms, and explores whether strategies to reduce uric acid will improve outcomes. The recent studies of xanthine oxidase inhibition are given particular focus. Epidemiological evidence supports the theory that uric acid is an independent risk factor for cardiovascular disease. Recent studies of losartan, atorvastatin and fenofibrate suggest that uric acid reduction contributes to the risk reduction offered by these therapies. Several small studies of xanthine oxidase inhibition have shown improvements in measures of cardiovascular function of a similar magnitude to that of other proven preventative treatments. These trial data and the convincing epidemiological evidence mandate that large clinical trials of uric acid-lowering strategies are performed in patients with or at high risk of cardiovascular disease. If such approaches are shown to be effective in reducing cardiovascular events, they would represent a novel and cost-effective preventative approach.

Dawson, Jesse; Walters, Matthew

2006-01-01

230

Urea transport through composite polyallylamine membranes  

NASA Technical Reports Server (NTRS)

Polyallylamine composite reverse osmosis membranes were prepared by plasma polymerization and deposition onto small-pored cellulose acetate/cellulose nitrate films. The polyallylamine coated the porous substrate with a thin uniform polymer film which exhibited water permeability and urea rejection, of interest because of the potential application of reverse osmosis to urine purification in closed environmental systems. The flux of C-14 labeled urea was studied under the influence of osmotic gradients provided by sodium chloride solutions. The urea flux was found to be enhanced by an osmotic pressure gradient in the same direction and diminished, but not prevented, by an opposing osmotic pressure gradient. Consideration is given to the mechanism of the urea transport, as well as to the influence of concentration polarization on the experimental results. The minimization of coupled flow in pores of a critical size range is apparently necessary to improve urea rejection.

Ballou, E. V.; Kubo, L. Y.; Spitze, L. A.; Wydeven, T.; Clark, J. A.

1977-01-01

231

High plasma uric acid concentration: causes and consequences  

PubMed Central

High plasma uric acid (UA) is a precipitating factor for gout and renal calculi as well as a strong risk factor for Metabolic Syndrome and cardiovascular disease. The main causes for higher plasma UA are either lower excretion, higher synthesis or both. Higher waist circumference and the BMI are associated with higher insulin resistance and leptin production, and both reduce uric acid excretion. The synthesis of fatty acids (tryglicerides) in the liver is associated with the de novo synthesis of purine, accelerating UA production. The role played by diet on hyperuricemia has not yet been fully clarified, but high intake of fructose-rich industrialized food and high alcohol intake (particularly beer) seem to influence uricemia. It is not known whether UA would be a causal factor or an antioxidant protective response. Most authors do not consider the UA as a risk factor, but presenting antioxidant function. UA contributes to > 50% of the antioxidant capacity of the blood. There is still no consensus if UA is a protective or a risk factor, however, it seems that acute elevation is a protective factor, whereas chronic elevation a risk for disease.

2012-01-01

232

LC-MS-MS Measurements of Urinary Creatinine and the Application of Creatinine Normalization Technique on Cotinine in Smokers' 24 Hour Urine  

PubMed Central

A simple and sensitive high performance liquid chromatography-tandem mass spectrometry (HPLC-ESI-MS-MS) method was developed and validated for the quantification of creatinine in human urine. The analysis was carried out on an Agilent Zorbax Eclipse XDB-C18 column (2.1 × 150?mm, 3.5??m). The mobile phase was 0.1% formic acid in water and 0.1% formic acid in acetonitrile (50/50, v/v). Linear calibration curves were obtained in the concentration range of 1–2000.0?ng/mL, with a lower limit of quantification of 0.99?ng/mL. The intra- and interday precision (RSD) values were below 3%. The method was successfully applied to a bioequivalence study of creatinine in Chinese smokers and nonsmokers. The total cotinine in 24?h urine and cotinine?:?creatinine ratio were also positively associated (Pearson R = 0.942, P < 0.0001). However, cotinine?:?creatinine ratio varied significantly across smoking groups for the difference of individual. 24?h urinary cotinine was more appropriate for expressing correlation with tar than cotinine?:?creatinine ratio.

Hou, Hongwei; Xiong, Wei; Zhang, Xiaotao; Song, Dongkui; Tang, Gangling; Hu, Qingyuan

2012-01-01

233

Evaluation of a handheld creatinine measurement device for real-time determination of serum creatinine in radiology departments  

PubMed Central

AIM: To assess the feasibility/accuracy of a commercial handheld device in the context of increased demand for point-of-care serum creatinine (SCr) determination. METHODS: In this institutional review board-approved, prospective study, 401 patients referred for contrast-enhanced computed tomography were included at two centres. Capillary (c)SCr was determined using two devices A+B and venous (v)SCr was determined in the centre’s laboratory. Method comparison statistics for both centres and for vSCr<>1.2 mg/dL, receiver operating characteristic analysis, negative predictive values (NPV), sensitivity and specificity were calculated pre-/post-curve offset correction with vSCr. RESULTS: Pearson’s coefficients for cSCr vs vSCr were: centre 1-A:0.93/B:0.92; centre 2-A:0.85/B:0.82 (all P < 0.0001). Overall correlation was better for vSCr > 1.2 mg/dL. The area under the receiver operating characteristic curves showed a high accuracy for cSCr, but the device underestimated SCr, which was confirmed by Bland-Altman plot. Addition of the offset correction factor to the original data from centre 1 resulted in an improvement in sensitivity for detecting patients at risk (> 1.2 mg/dL), whilst maintaining acceptable specificity and improving NPV. CONCLUSION: This study showed the feasibility of SCr determination using the evaluated handheld device in a routine clinical setting. The device showed high sensitivity and high NPV, but may significantly underestimate SCr without offset correction to local laboratories.

Haneder, Stefan; Gutfleisch, Alexandra; Meier, Claudia; Brade, Joachim; Hannak, Dieter; Schoenberg, Stefan O; Becker, Christoph R; Michaely, Henrik J

2012-01-01

234

Ammonia sanitisation of sewage sludge using urea.  

PubMed

The aim of the study was to develop a simple, low-cost treatment for sewage sludge using urea as a sanitising agent. Sewage sludge was spiked with Enterococcus faecalis and Salmonella typhimurium, treated with 0.5, 1, 1.5 and 2% w/w urea at laboratory scale, and the viability was monitored during 4 months of storage at 4, 10 and 22 °C (only 0.5%). A linear relationship was identified between Salmonella spp. inactivation rate and ammonia (NH3) concentration. Temperature had a positive impact on Salmonella spp. inactivation at higher temperatures, but in the range 4-10 °C temperature influenced this inactivation merely by its impact on the ammonia equilibrium. Enterococcus spp. was more persistent and a lag phase of up to 11 weeks was observed. Higher temperature and ammonia concentration reduced the lag phase duration significantly, and also had a clear effect on the inactivation rate for the treatments with 0.5% urea at 22 °C and 2% urea at 4 and 10 °C. Urea sanitisation of sewage sludge can give a 2 log10 reduction of Enterococcus spp. and more than a 5 log10 reduction of Salmonella spp. within 6 weeks with either 0.5% w/w urea at 22 °C or 2% urea at 10 °C. PMID:24185072

Fidjeland, Jørgen; Lalander, Cecilia; Jönsson, Håkan; Vinnerås, Björn

2013-01-01

235

Serum uric acid: a forgotten prognostic marker in acute coronary syndromes?  

PubMed Central

Background: Serum uric acid (UA) has been shown to be an independent predictor of outcome in the general population and in patients with heart failure. There are, however, limited data regarding the prognostic value of UA in the context of acute coronary syndromes (ACS) particularly in medium-term follow up and the available results are contradictory. Materials and methods: Study of consecutive patients admitted with an ACS (with and without ST-segment elevation) at a single-centre coronary care unit. Primary endpoint was all-cause mortality at 1-year follow up. We evaluated if serum UA is an independent predictor of outcome and if it has any added value on top of GRACE risk score for risk prediction. Results: We included 683 patients, mean age 64±13 years, 69% males. In-hospital and 1-year mortality were 4.5 and 7.6% respectively. The best cut-off of UA to predict 1-year mortality was 6.25 mg/dl (sensitivity 59%, specificity 72%) and 30.2% of the patients had an increased UA according to this cut off. Independent predictors of UA were male gender (?= 0.078), body mass index (?=0.163), diuretics before admission (?=0.142), and admission serum creatinine (?=0.403). One-year mortality was significantly higher in patients with increased UA (15.5 vs. 4.2%, p<0.001; log rank, p<0.001). After adjustment, both increased UA as a categorical variable (HR 2.25, 95% CI 1.23–4.13, p=0.008) and as a continuous variable (HR 1.26, 95% CI 1.13–1.41, p<0.001) are independent predictors of mortality. The AUC increases only slightly after inclusion of UA in the model with GRACE risk score (from 0.78 to 0.79, p=0.350). Both models had a good fit; however, model fit worsened after inclusion of UA. Overall, the inclusion of UA in the original was associated with an improvement in both the net reclassification improvement (continuous NRI=44%), and the integrated discrimination improvement (IDI=0.052) suggesting effective reclassification. Conclusions: Serum UA is an independent predictor of all-cause mortality in medium-term after the whole spectrum of ACS and has an added value for risk stratification.

Lousinha, Ana; Labandeiro, Jorge; Miranda, Fernando; Papoila, Ana L; Oliveira, Jose A; Ferreira, Maria L; Ferreira, Rui C

2013-01-01

236

Serum uric acid level and its association with cardiometabolic risk factors in prediabetic subjects  

PubMed Central

Background: Excess serum uric acid (UA) accumulation can lead to various diseases. Increasing evidences reveal that UA may have a key role in the pathogenesis of metabolic syndrome. Little is known about the associations of UA levels with cardiometabolic risk factors in prediabetic individuals. This study was designed to evaluate the association between UA and cardiometabolic risk factors in prediabetic subjects with family history of diabetes compared with those with normal glucose tolerance (NGT). Materials and Methods: In a cross-sectional setting, a sample containing 643 (302 prediabetic subjects and 341 normal) of the first-degree relatives of diabetic patients aged 35-55-years old were investigated. Samples were assessed in prediabetic and normal groups using glucose tolerance categories. Prediabetes was defined based on American Diabetes Association (ADA) criteria. Body weight and height, systolic and diastolic blood pressure (SBP and DBP), UA, creatinine (Cr), albumin (Alb), fasting blood glucose (FBG), hemoglobin A1c (HbA1c), and lipid profiles were measured and compared between two groups. Results: Prediabetic persons were older and obese than normal persons. Also, prediabetic persons (5.2 ± 1.3 mg/dl) had significantly higher UA than normal persons (4.9 ± 1.4 mg/dl) (P < 0.05). FBG after 0, 30, 60, and 120 min in prediabetic were higher than normal persons (P < 0.001). With respect to metabolic parameters, the patients in the higher UA quartiles exhibited higher levels of body mass index (BMI), SBP, FBG and triglycerides (TG). The higher quartiles of UA tended to be associated with higher BMI and higher total cholesterol (TC) in females prediabetic persons. Based on logistic regression analysis in different models, UA was positively (odds ratio (OR) >1, P < 0.05) associated with glucose tolerance categories. This association remained statistically significant after adjusting the effects of age and BMI. Also, the association between glucose tolerance categories and UA were positively significant in both genders. Conclusion: High UA level was associated with some cardiometabolic risk factors in prediabetic individuals compared with normal person. UA level was also a significant predictor for prediabetes condition.

Iraj, Bijan; Feizi, Awat; Abdar-Esfahani, Morteza; Heidari-Beni, Motahar; Zare, Maryam; Amini, Masoud; Parsa, Fatemeh

2014-01-01

237

Creatinine as a measure of lean body mass during treatment of acute lymphoblastic leukemia in childhood.  

PubMed

Protein energy malnutrition is well-recognized in children with acute leukemia and may result in loss of lean body mass (LBM) with attendant morbidities. Much of the LBM consists of skeletal muscle, the mass of which is reflected in urinary creatinine excretion. As accurate 24 hours urine collections are challenging in children, we investigated the prospect that serum creatinine concentration provides a measure of LBM. Eleven children with acute lymphoblastic leukemia were assessed at 7 time points (6-mo intervals) from diagnosis to 1 year after the completion of therapy. LBM was measured as fat-free mass by dual energy x-ray absorptiometry (DXA scans) and correlated with serum creatinine concentration and 24 hours urine creatinine excretion. As expected, there was a strong correlation between 24 hours urinary creatinine excretion and LBM from DXA scans (r=0.79, P<0.001). Serum creatinine concentration also correlated with LBM (r=0.52, P<0.001). Serum creatinine concentration provides a surrogate measure of LBM in children with acute lymphoblastic leukemia. This will be especially useful in countries with limited resources in which more sophisticated measures, such as DXA scans, are seldom available. PMID:21178703

Morrison, Judy; Nayiager, Trishana; Webber, Colin E; Sala, Alessandra; Barr, Ronald

2011-01-01

238

Array of potentiometric sensors for the analysis of creatinine in urine samples.  

PubMed

The development of potentiometric biosensors for creatinine based on creatinine iminohydrolase (E.C. 3.5.4.21) immobilized on chitosan membranes coupled to a nonactin based ammonium ion selective electrode is described. The response characteristics of three types of biosensors with the enzyme immobilized by three different procedures were evaluated. The biosensors with better response characteristics were obtained by coupling the ammonium ion selective electrodes to chitosan membranes with the enzyme immobilized by adsorption. The linear response range of these biosensors to creatinine was 10(-4) to 10(-2) M, the response time was between 30 and 60 s, they showed an operational lifetime of 44 days and the slope of the response to creatinine in the first day varied between 50 and 52 mV decade-1. An array of six potentiometric sensors, constituted by two creatinine biosensors and four ion selective electrodes for potassium, sodium, ammonium and calcium was calibrated and a multivariate model based on PLS1 for the response to creatinine was obtained and validated. The array was used for the analysis of creatinine in urine samples and the results were compared with the results of a clinical analysis laboratory, based on the Jaffé reaction. PMID:12195948

Magalhães, Júlia M C S; Machado, Adélio A S C

2002-08-01

239

Colorimetric test-systems for creatinine detection based on composite molecularly imprinted polymer membranes.  

PubMed

An easy-to-use colorimetric test-system for the efficient detection of creatinine in aqueous samples was developed. The test-system is based on composite molecularly imprinted polymer (MIP) membranes with artificial receptor sites capable of creatinine recognition. A thin MIP layer was created on the surface of microfiltration polyvinylidene fluoride (PVDF) membranes using method of photo-initiated grafting polymerization. The MIP layer was obtained by co-polymerization of a functional monomer (e.g. 2-acrylamido-2-methyl-1-propanesulfonic acid, itaconic acid or methacrylic acid) with N, N'-methylenebisacrylamide as a cross-linker. The choice of the functional monomer was based on the results of computational modeling. The creatinine-selective composite MIP membranes were used for measuring creatinine in aqueous samples. Creatinine molecules were selectively adsorbed by the MIP membranes and quantified using color reaction with picrates. The intensity of MIP membranes staining was proportional to creatinine concentration in an analyzed sample. The colorimetric test-system based on the composite MIP membranes was characterized with 0.25 mM detection limit and 0.25-2.5mM linear dynamic range. Storage stability of the MIP membranes was estimated as at least 1 year at room temperature. As compared to the traditional methods of creatinine detection the developed test-system is characterized by simplicity of operation, small size and low cost. PMID:23498699

Sergeyeva, T A; Gorbach, L A; Piletska, E V; Piletsky, S A; Brovko, O O; Honcharova, L A; Lutsyk, O D; Sergeeva, L M; Zinchenko, O A; El'skaya, A V

2013-04-01

240

Reference ranges for plasma cystatin C and creatinine measurements in premature infants, neonates, and older children  

PubMed Central

AIM—To establish a reference range in the paediatric population for the new glomerular filtration rate (GFR) marker, cystatin C, and to compare it with that of creatinine.?METHODS—Cystatin C and creatinine were measured by particle enhanced nephelometric immunoassay (PENIA) and fixed interval Jaffé methods, respectively, in 291 children aged 1 day to 17 years, including 30 premature infants with gestational ages ranging from 24 to 36weeks.?RESULTS—In the premature infants, concentrations of both cystatin C and creatinine were significantly raised compared with term infants, with cystatin C concentrations being between 1.10 and 2.06 mg/litre and creatinine between 32 and 135 µmol/litre. In premature infants, there was no significant relation between gestational age and cystatin C or creatinine concentration. Creatinine concentrations fell to a nadir at 4 months of age, rising gradually to adult values by about 15-17 years of age, in contrast to cystatin C, which fell to a mean concentration of 0.80 mg/litre by the 1st year of life, and remained constant throughout adulthood up to the age of 50 years. Neither analyte showed any influence of sex.?CONCLUSION—The measurement of cystatin C, rather than creatinine, is more practical for monitoring GFR changes in the paediatric population.?

Finney, H; Newman, D; Thakkar, H; Fell, J; Price, C

2000-01-01

241

Inexpensive purification of urea waste streams  

US Patent & Trademark Office Database

Urea is destroyed in aqueous waste streams containing various anions and cations plus urea by contacting the stream with a cation exchange resin, then reacting the resulting stream with nitric oxide, nitrous acid or a nitrite salt to convert the urea to nitrogen, carbon dioxide and water and treating the resulting stream with an anion exchange resin. A pure aqueous stream is obtained which does not adversely affect the environment and which may be recycled to a plant as fresh water resulting in large monetary savings in fresh water cost.

1980-02-12

242

Gasification of wood to produce urea  

SciTech Connect

A study is described which examines the economic feasibility of producing urea by the gasification of wood. The process includes an oxygen blown fluidized bed gasifier, an air separation plant supplying both oxygen and nitrogen to the process, the use of a water gas process for hydrogen production, an Amine Guard AG/T carbon dioxide removal system, and a pressure swing absorption system for purifying the hydrogen used in the ammonia synthesis. Ammonia combined with carbon dioxide produces ammonium carbamate which is dehydrated to urea. The economic analysis shows that urea can be produced from wood at a profit. 5 references, 5 figures, 4 tables.

Bettinger, J.A.; Kosstrin, H.M.

1984-06-01

243

Differences in urine cadmium associations with kidney outcomes based on serum creatinine and cystatin C  

SciTech Connect

Cadmium is a well-known nephrotoxicant; chronic exposure increases risk for chronic kidney disease. Recently, however, associations between urine cadmium and higher creatinine-based estimated glomerular filtration rate (eGFR) have been reported. Analyses utilizing alternate biomarkers of kidney function allow evaluation of potential mechanisms for these observations. We compared associations of urine cadmium with kidney function measures based on serum cystatin C to those with serum creatinine in 712 lead workers. Mean (standard deviation) molybdenum-corrected urine cadmium, Modification of Diet in Renal Disease (MDRD) eGFR and multi-variable cystatin C eGFR were 1.02 (0.65) {mu}g/g creatinine, and 97.4 (19.2) and 112.0 (17.7) mL/min/1.73 m{sup 2}, respectively. The eGFR measures were moderately correlated (r{sub s}=0.5; p<0.001). After adjustment, ln (urine cadmium) was not associated with serum cystatin-C-based measures. However, higher ln (urine cadmium) was associated with higher creatinine-based eGFRs including the MDRD and an equation incorporating serum cystatin C and creatinine (beta-coefficient=4.1 mL/min/1.73 m{sup 2}; 95% confidence interval=1.6, 6.6). Urine creatinine was associated with serum creatinine-based but not cystatin-C-based eGFRs. These results support a biomarker-specific, rather than a kidney function, effect underlying the associations observed between higher urine cadmium and creatinine-based kidney function measures. Given the routine use of serum and urine creatinine in kidney and biomarker research, additional research to elucidate the mechanism(s) for these associations is essential.

Weaver, Virginia M., E-mail: vweaver@jhsph.edu [Division of Occupational and Environmental Health, Department of Environmental Health Sciences, Johns Hopkins University Bloomberg School of Public Health, 615N. Wolfe St., Rm. 7041, Baltimore, MD 21205 (United States); Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD (United States); Welch Center for Prevention, Epidemiology and Clinical Research, Johns Hopkins Medical Institutions, Baltimore, MD (United States); Kim, Nam-Soo; Lee, Byung-Kook [Institute of Industrial Medicine, SoonChunHyang University, Asan (Korea, Republic of)] [Institute of Industrial Medicine, SoonChunHyang University, Asan (Korea, Republic of); Parsons, Patrick J. [Laboratory of Inorganic and Nuclear Chemistry, Wadsworth Center, New York State Department of Health, Albany, NY (United States) [Laboratory of Inorganic and Nuclear Chemistry, Wadsworth Center, New York State Department of Health, Albany, NY (United States); Department of Environmental Health Sciences, School of Public Health, University at Albany, Albany, NY (United States); Spector, June [Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA (United States)] [Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA (United States); Fadrowski, Jeffrey [Welch Center for Prevention, Epidemiology and Clinical Research, Johns Hopkins Medical Institutions, Baltimore, MD (United States) [Welch Center for Prevention, Epidemiology and Clinical Research, Johns Hopkins Medical Institutions, Baltimore, MD (United States); Department of Pediatrics, Johns Hopkins School of Medicine, Baltimore, MD (United States); Jaar, Bernard G. [Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD (United States) [Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD (United States); Welch Center for Prevention, Epidemiology and Clinical Research, Johns Hopkins Medical Institutions, Baltimore, MD (United States); Department of Epidemiology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD (United States); Steuerwald, Amy J. [Laboratory of Inorganic and Nuclear Chemistry, Wadsworth Center, New York State Department of Health, Albany, NY (United States) [Laboratory of Inorganic and Nuclear Chemistry, Wadsworth Center, New York State Department of Health, Albany, NY (United States); Department of Environmental Health Sciences, School of Public Health, University at Albany, Albany, NY (United States); Todd, Andrew C. [Department of Preventive Medicine, Mount Sinai School of Medicine, New York, NY (United States)] [Department of Preventive Medicine, Mount Sinai School of Medicine, New York, NY (United States); and others

2011-11-15

244

Differences in urine cadmium associations with kidney outcomes based on serum creatinine and cystatin C  

PubMed Central

Cadmium is a well known nephrotoxicant; chronic exposure increases risk for chronic kidney disease. Recently, however, associations between urine cadmium and higher creatinine-based estimated glomerular filtration rate (eGFR) have been reported. Analyses utilizing alternate biomarkers of kidney function allow evaluation of potential mechanisms for these observations. We compared associations of urine cadmium with kidney function measures based on serum cystatin C to those with serum creatinine in 712 lead workers. Mean (standard deviation) molybdenum-corrected urine cadmium, Modification of Diet in Renal Disease (MDRD) eGFR and multi-variable cystatin C eGFR were 1.02 (0.65) ?g/g creatinine, and 97.4 (19.2) and 112.0 (17.7) mL/min/1.73 m2, respectively. The eGFR measures were moderately correlated (rs = 0.5; p less than 0.001). After adjustment, ln(urine cadmium) was not associated with serum cystatin-C-based measures. However, higher ln(urine cadmium) was associated with higher creatinine-based eGFRs including the MDRD and an equation incorporating serum cystatin C and creatinine (beta-coefficient = 4.1 ml/min/1.73 m2; 95% confidence interval =1.6, 6.6). Urine creatinine was associated with serum creatinine-based but not cystatin-C-based eGFRs. These results support a biomarker-specific, rather than a kidney function, effect underlying the associations observed between higher urine cadmium and creatinine-based kidney function measures. Given the routine use of serum and urine creatinine in kidney and biomarker research, additional research to elucidate the mechanism(s) for these associations is essential.

Weaver, Virginia M.; Kim, Nam-Soo; Lee, Byung-Kook; Parsons, Patrick J.; Spector, June; Fadrowski, Jeffrey; Jaar, Bernard G.; Steuerwald, Amy J.; Todd, Andrew C.; Simon, David; Schwartz, Brian S.

2011-01-01

245

Uric acid deposits and estivation in the invasive apple-snail, Pomacea canaliculata.  

PubMed

The physiological ability to estivate is relevant for the maintenance of population size in the invasive Pomacea canaliculata. However, tissue reoxygenation during arousal from estivation poses the problem of acute oxidative stress. Uric acid is a potent antioxidant in several systems and it is stored in specialized tissues of P. canaliculata. Changes in tissue concentration of thiobarbituric acid reactive substances (TBARS), uric acid and allantoin were measured during estivation and arousal in P. canaliculata. Both TBARS and uric acid increased two-fold during 45 days estivation, probably as a consequence of concomitant oxyradical production during uric acid synthesis by xanthine oxidase. However, after arousal was induced, uric acid and TBARS dropped to or near baseline levels within 20 min and remained low up to 24h after arousal induction, while the urate oxidation product allantoin continuously rose to a maximum at 24h after induction, indicating the participation of uric acid as an antioxidant during reoxygenation. Neither uric acid nor allantoin was detected in the excreta during this 24h period. Urate oxidase activity was also found in organs of active snails, but activity shut down during estivation and only a partial and sustained recovery was observed in the midgut gland. PMID:21182978

Giraud-Billoud, Maximiliano; Abud, María A; Cueto, Juan A; Vega, Israel A; Castro-Vazquez, Alfredo

2011-04-01

246

The diurnal variation in urine acidification differs between normal individuals and uric acid stone formers  

PubMed Central

Many biologic functions follow circadian rhythms driven by internal and external cues that synchronize and coordinate organ physiology to diurnal changes in the environment and behavior. Urinary acid-base parameters follow diurnal patterns and it is thought these changes are due to periodic surges in gastric acid secretion. Abnormal urine pH is a risk factor for specific types of nephrolithiasis and uric acid stones are typical of excessively low urine pH. Here we placed 9 healthy volunteers and 10 uric acid stone formers on fixed metabolic diets to study the diurnal pattern of urinary acidification. All showed clear diurnal trends in urinary acidification but none of the patterns were affected by inhibitors of the gastric proton pump. Uric acid stone formers had similar patterns of change through the day but their urine pH was always lower compared to healthy volunteers. Uric acid stone formers excreted more acid (normalized to acid ingestion) with the excess excreted primarily as titratable acid rather than ammonium. Urine base excretion was also lower in uric acid stone formers (normalized to base ingestion) along with lower plasma bicarbonate concentrations during part of the day. Thus, increased net acid presentation to the kidney and the preferential use of buffers, other than ammonium, result in much higher concentrations of un-dissociated uric acid throughout the day and consequently an increased risk of uric acid stones.

Cameron, Mary Ann; Maalouf, Naim M.; Poindexter, John; Adams-Huet, Beverley; Sakhaee, Khashayar; Moe, Orson W.

2012-01-01

247

Serum Uric Acid Level and Endothelial Dysfunction in Patients with Nondiabetic Chronic Kidney Disease  

PubMed Central

Background An elevated serum uric acid level is strongly associated with endothelial dysfunction and inflammation, both of which are common in chronic kidney disease (CKD). We hypothesized that endothelial dysfunction in subjects with CKD would correlate with uric acid levels. Materials and Methods We evaluated the association between serum uric acid level and ultrasonographic flow-mediated dilatation (FMD) in 263 of 486 patients with recently diagnosed CKD (stage 3–5) (48% male, age 52 ± 12 years). To minimize confounding, 233 patients were excluded because they were diabetic, had established cardiovascular complications or were taking drugs (renin-angiotensin system blockers, statins) interfering with vascular function. Results Serum uric acid level was significantly increased in all stages of CKD and strongly correlated with estimated glomerular filtration rate (eGFR-MDRD); FMD was inversely associated with serum uric acid (r = ?0.49, p < 0.001). The association of serum uric acid with FMD remained after adjustment for age, gender, smoking, LDL cholesterol, eGFR, high-sensitivity C-reactive protein, systolic blood pressure, proteinuria, and homeostatic model assessment index (? = ?0.27, p < 0.001). Conclusion Increased serum uric acid is an independent predictor of endothelial dysfunction in subjects with CKD.

Kanbay, Mehmet; Yilmaz, Mahmut Ilker; Sonmez, Alper; Turgut, Faruk; Saglam, Mutlu; Cakir, Erdinc; Yenicesu, Mujdat; Covic, Adrian; Jalal, Diana; Johnson, Richard J.

2011-01-01

248

Serum uric acid and appropriate cutoff value for prediction of metabolic syndrome among Chinese adults  

PubMed Central

The relation between serum uric acid and metabolic syndrome is observed not only with frank hyperuricemia but also with serum uric acid levels within the normal range. The current “normal” range set for hyperuricemia often fails to identify patients with potential metabolic disorders. We investigate the association between serum uric acid within the normal range and incident metabolic syndrome risk, and further to determine the optimal cut-off value of serum uric acid for the diagnosis or prediction of metabolic syndrome. A total of 7399 Chinese adults (2957 men and 4442 women; ?20 years) free of metabolic syndrome were followed for 3 years. During the 3-year follow-up, 1190 normouricemic individuals developed metabolic syndrome (16.1%). After adjusting the associated variables, the top quartile of serum uric acid levels was associated with higher metabolic syndrome development compared with the bottom quartile in men (hazard ratio (HR), 1.29; p<0.05) and women (HR, 1.62; p<0.05). ROC curve analysis indicated that the optimal cut-off values for serum uric acid to identify metabolic syndrome were 6.3 mg/dl in men and 4.9 mg/dl in women. Our results suggested that high baseline serum uric acid levels within the normal range predict future development of metabolic syndrome after 3 y of follow-up.

Zhang, Mei-lin; Gao, Yu-xia; Wang, Xuan; Chang, Hong; Huang, Guo-wei

2013-01-01

249

Uric acid-induced endothelial dysfunction is associated with mitochondrial alterations and decreased intracellular ATP concentrations  

PubMed Central

Background/Aims Endothelial dysfunction is associated with mitochondrial alterations. We hypothesized that uric acid, which can induce endothelial dysfunction in vitro and in vivo, might also alter mitochondrial function. Methods Human aortic endothelial cells were exposed to soluble uric acid and measurements of oxidative stress, nitric oxide, mitochondrial density, ATP production, aconitase-2 and enoyl co-A hydratase-1 expression, and aconitase-2 activity in isolated mitochondria were determined. The effect of hyperuricemia upon renal mitochondrial integrity was also assessed in rats treated with oxonic acid that inhibits the enzyme uricase that degrades uric acid. Results Uric acid induced endothelial dysfunction was associated with reduced mitochondrial mass and ATP production. Uric acid also decreased aconitase-2 activity and lowered enoyl CoA hydratase-1 expression. Hyperuricemic rats showed increased mitDNA damage in association with higher levels of intrarenal uric acid and oxidative stress. Conclusions Uric acid induced endothelial dysfunction is associated with mitochondrial alterations and decreased intracellular ATP. These studies provide additional evidence for a deleterious effect of UA on vascular function that could be important in the pathogenesis and progression of hypertension, vascular disease and renal disease.

Sanchez-Lozada, Laura Gabriela; Lanaspa, Miguel A.; Cristobal-Garcia, Magdalena; Garcia-Arroyo, Fernando; Soto, Virgilia; Cruz-Robles, David; Nakagawa, Takahiko; Yu, Min-A; Kang, Duk-Hee; Johnson, Richard J

2013-01-01

250

An amperometric uric acid biosensor based on chitosan-carbon nanotubes electrospun nanofiber on silver nanoparticles.  

PubMed

A novel amperometric uric acid biosensor was fabricated by immobilizing uricase on an electrospun nanocomposite of chitosan-carbon nanotubes nanofiber (Chi-CNTsNF) covering an electrodeposited layer of silver nanoparticles (AgNPs) on a gold electrode (uricase/Chi-CNTsNF/AgNPs/Au). The uric acid response was determined at an optimum applied potential of -0.35 V vs Ag/AgCl in a flow-injection system based on the change of the reduction current for dissolved oxygen during oxidation of uric acid by the immobilized uricase. The response was directly proportional to the uric acid concentration. Under the optimum conditions, the fabricated uric acid biosensor had a very wide linear range, 1.0-400 ?mol L(-1), with a very low limit of detection of 1.0 ?mol L(-1) (s/n?=?3). The operational stability of the uricase/Chi-CNTsNF/AgNPs/Au biosensor (up to 205 injections) was excellent and the storage life was more than six weeks. A low Michaelis-Menten constant of 0.21 mmol L(-1) indicated that the immobilized uricase had high affinity for uric acid. The presence of potential common interfering substances, for example ascorbic acid, glucose, and lactic acid, had negligible effects on the performance of the biosensor. When used for analysis of uric acid in serum samples, the results agreed well with those obtained by use of the standard enzymatic colorimetric method (P?>?0.05). PMID:24718436

Numnuam, Apon; Thavarungkul, Panote; Kanatharana, Proespichaya

2014-06-01

251

Systemic uric acid administration increases serum antioxidant capacity in healthy volunteers.  

PubMed

Oxidative stress plays an important role in the development of atherosclerosis and contributes to tissue damage that occurs as a consequence, particularly in myocardial infarction and acute stroke. Antioxidant properties of uric acid have long been recognized and, as a result of its comparatively high serum concentrations, it is the most abundant scavenger of free radicals in humans. Elevation of serum uric acid concentration occurs as a physiologic response to increased oxidative stress-for example, during acute exercise-thus providing a counter-regulatory increase in antioxidant defenses. In view of its antioxidant properties, uric acid may have potentially important and beneficial effects within the cardiovascular system. We wished to investigate whether administration of uric acid was feasible and if it could have an impact on antioxidant function in vivo. We have, therefore, performed a randomized, placebo-controlled double-blind study of the effects of systemic administration of uric acid, 1,000 mg, in healthy volunteers, compared with vitamin C, 1,000 mg. We observed a significant increase in serum free-radical scavenging capacity from baseline during uric acid and vitamin C infusion, using two methodologically distinct antioxidant assays. The effect of uric acid was substantially greater than that of vitamin C. PMID:11486241

Waring, W S; Webb, D J; Maxwell, S R

2001-09-01

252

Defining the at risk patients for contrast induced nephropathy after coronary angiography; 24-h urine creatinine versus Cockcroft-Gault equation or serum creatinine level  

PubMed Central

Background: Definitions of chronic kidney disease (CKD) in many catheterization laboratories have relied on the serum creatinine (Scr) rather than glomerular filtration rate (GFR). Regarding that CKD is the primary predisposing factor for contrast induced nephropathy (CIN), we compared the sensitivity of calculated GFR by 24-h Urine creatinine with Cockcroft-Gault (CG) equation and Scr level to define at risk patients for CIN who were undergone coronary angiography (CAG). Materials and Methods: Two hundred fifty four subjects who were candidate for CAG and had normal creatinine level were enrolled. Before CAG, GFR was calculated from a 24-h urine collection, CG equation and a single Scr sample regarding to previously described protocol. Contrast volume used for each case <100 ml. CIN was defined as a 0.5 mg/dL or 25% elevation in the Scr. Results: CIN occurred in 10.6%. Baseline GFR, the volume of contrast agent, and diabetes were the independent risk factors for CIN. GFR was less than 60 ml/min/1.73 m2 in 28% and 23.2% of patients regarding to 24-h urine creatinine and CG equation, respectively. In CIN prediction, 24-h urine creatinine estimated GFR had 85.2%, 59.3% and CG equation GFR had 78.9%, 81.1% sensitivity and specificity, respectively. Conclusion: Although, GFR estimated by CG equation has less sensitivity than GFR calculated from 24-h creatinine in CIN probability, but it is better than Scr alone and because of cost-effectiveness and convenience using of this method, we suggest at least using CG equation for GFR calculation before CIN, especially in diabetic and/or older than 60 years cases.

Assareh, Ahmadreza; Yazdankhah, Saeed; Ahmadzadeh, Ahmad; Yadollahzadeh, Mahdi; Nasehi, Nasim; Haybar, Habib

2012-01-01

253

Uric acid synthesis by rat liver supernatants from purine bases, nucleosides and nucleotides. Effect of allopurinol.  

PubMed

The synthesis of uric acid from purine bases, nucleosides and nucleotides has been measured in reaction mixtures containing rat liver supernatant and each one of the following compounds at 1 mM concentration (except xanthine, 0.5 mM and guanosine and guanine, 0.1 mM). The rates of the reaction, expressed as nanomoles of uric acid synthesized g-1 of wet liver min-1 were: ATP, 10; ADP, 37; AMP, 62; adenosine, 108; adenine 6; adenylosuccinate, 9; IMP 32; inosine, 112; hypoxanthine, 50; GTP, 19; GDP, 19; GMP, 27; guanosine, 34; guanine, 72; XMP, 10; xanthosine, 24; xanthine, 144. These figures divided by 55 correspond to nanomoles of uric acid synthesized min-1 per mg-1 of protein. The rate of synthesis of uric acid obtained with each one of those compounds at 0.1 and 0.05 mM concentrations was also determined. ATP (1 mM) strongly inhibited uric acid synthesis from 0.05 mM AMP (91 per cent) and from 0.05 mM ADP (88 per cent), but not from adenosine. CTP or UTP (1 mM) also inhibited (by more than 90 per cent) the synthesis of uric acid from 0.05 mM AMP. Xanthine oxidase was inhibited by concentrations of hypoxanthine higher than 0.012 mM. The results favour the view that the level of uric acid in plasma may be an index of the energetic state of the organism. Allopurinol, besides inhibiting uric acid synthesis, reduced the rate of degradation of AMP. The ability of crude extracts to catabolize purine nucleotides to uric acid is an important factor to be considered when some enzymes related to purine nucleotide metabolism, particularly CTP synthase, are measured in crude liver extracts. PMID:7834812

Bleisch, S; Sillero, M A; Torrecilla, A; Sillero, A

1994-12-01

254

Uric acid, a nucleic acid degradation product, down-regulates dsRNA-triggered arthritis.  

PubMed

Uric acid, the naturally occurring degradation product of purine metabolism, is a danger signal, driving maturation of dendritic cells. It is well known that uric acid crystals display potent proinflammatory properties--the cause of gout--whereas the biological properties of soluble uric acid are less well documented. We have demonstrated previously that nucleic acids of endogenous and exogenous origin display proinflammatory properties. The aim of the present study was to assess the impact of soluble uric acid on in vivo inflammatory responses. Mice were administered with uric acid suspension in saline or saline alone prior to induction of neutrophil-mediated inflammation, delayed-type hypersensitivity, histamin-induced edema (measure of vasodilation capacity), as well as double-stranded (ds)RNA-triggered arthritis. Frequency and severity of arthritis were decreased significantly in mice exposed to dsRNA and simultaneously treated with uric acid as compared with saline-treated controls. Also, granulocyte-mediated inflammatory response and vasodilation capacity were reduced significantly in mice treated with uric acid as compared with their control group. The data suggest that down-regulation of inflammation was mediated by skewing the inflammatory response from the peripheral sites to the peritoneal cavity and down-regulating vasodilatatory capacity and thereby affecting leukocyte migration. In contrast, the T cell-mediated delayed-type hypersensitivity reaction was not affected significantly in mice exposed to uric acid. These findings demonstrate that uric acid displays a potent, distant anti-inflammatory effect in vivo. This property seems to be mediated by down-regulation of neutrophil influx to the site of inflammatory insult. PMID:16387838

Zare, Fariba; Magnusson, Mattias; Bergström, Tomas; Brisslert, Mikael; Josefsson, Elisabet; Karlsson, Anna; Tarkowski, Andrej

2006-03-01

255

Is it time to revise the normal range of serum uric acid levels?  

PubMed

The actual reference range of serum uric acid has been assessed according to its variations among healthy individuals. i.e. those without clinical evidence of gout. By this approach, serum uric acid values between 3.5 and 7.2 mg/dL in adult males and postmenopausal women and between 2.6 and 6.0 mg/dL in premenopausal women have been identified as normal in many countries. However, this definition of normal range of serum uric acid in the general population is inevitably influenced by what we consider as "normal", since the absence of gout flares does not necessarily imply the absence of uric acid-related damage. Indeed, a growing body of evidence indicates that silent deposition of monosodium urate crystals as a result of hyperuricaemia may occur and lead to early destructive skeletal changes. In addition, a growing body of evidences demonstrates that uric acid might play a pathophysiological role in many "cardio-nephro-metabolic" disorders, which seems to be independent of the deposition of monosodium urate crystals, since it is evident also for serum uric acid concentrations below the saturation point for monosodium urate. Taken together, these findings strongly suggest to carefully reconsider the concept of "asymptomaticity" for chronic hyperuricemia and to consequently revise the normal range of serum uric acid levels also considering the progressive worldwide increase of circulating levels of uric acid, which could lead to a "shift to right" (i.e. toward higher values) of normal range. In the light of the new scientific knowledge on the pathophysiological role of uric acid in human disease, a threshold value < 6.0 mg/dL (< 360 µmol/L) seems to better identify true "healthy subjects" and should reasonably be considered for all subjects. PMID:24867507

Desideri, G; Castaldo, G; Lombardi, A; Mussap, M; Testa, A; Pontremoli, R; Punzi, L; Borghi, C

2014-05-01

256

Serum Uric Acid Levels and Cerebral Microbleeds in Patients with Acute Ischemic Stroke  

PubMed Central

Unlike experimental studies indicating a neuroprotective property of uric acid, clinical studies have shown that elevated levels of uric acid are associated with a risk of ischemic stroke. However, the association of uric acid with cerebral hemorrhage has seldom been tested. We aimed to elucidate the association between uric acid and cerebral microbleeds (CMBs), a hemorrhage-prone cerebral microangiopathy. Seven hundred twenty-four patients with ischemic stroke who were consecutively admitted to our hospital were included in this study. We collected demographic, clinical, and laboratory data, including uric acid level, and examined the presence of CMBs using T2*-weighted gradient-echo MRI. We used logistic regression analysis to examine an independent association between uric acid and CMBs. Two-hundred twenty-six patients had CMBs (31.2%). After adjusting for possible confounders, elevated uric acid was independently associated with the presence of CMBs (the highest quartile vs. lowest quartile, adjusted odd ratio [OR], 1.98; 95% confidence interval [CI], 1.16–3.39). This association retained in patients with deep or infratentorial CMBs (with or without lobar CMBs) but not among those with lobar CMBs. In addition, this association was robust among patients with hypertension (the highest quartile vs. lowest quartile, adjusted OR, 2.74; 95% CI, 1.43–5.24). In contrast, we did not find the association in patients without hypertension. We demonstrated that serum uric acid is independently associated with the presence of CMBs. In particular, the relation between uric acid and CMBs was robust in hypertensive patients.

Ryu, Wi-Sun; Kim, Chi Kyung; Kim, Beom Joon; Lee, Seung-Hoon

2013-01-01

257

Diagnostic accuracy of urinary spot protein:creatinine ratio for proteinuria in hypertensive pregnant women: systematic review  

Microsoft Academic Search

Objective To review the spot protein:creatinine ratio and albumin:creatinine ratio as diagnostic tests for significant proteinuria in hypertensive pregnant women.Design Systematic review.Data sources Medline and Embase, the Cochrane Library, reference lists, and experts.Review methods Literature search (1980-2007) for articles of the spot protein:creatinine ratio or albumin:creatinine ratio in hypertensive pregnancy, with 24 hour proteinuria as the comparator.Results 13 studies concerned

Anne-Marie Côté; Mark A Brown; Elaine Lam; Peter von Dadelszen; Tabassum Firoz; Robert M Liston; Laura A Magee

2008-01-01

258

Coulometric titration of urea with electrogenerated hypobromite.  

PubMed

A definitive method is described for the indirect assay of several tens of milligrams of urea by coulometric titration. Urea was decomposed in concentrated sulfuric acid using a Kjeldahl flask. Subsequently, the formed ammonium ion was titrated with electrogenerated hypobromite ion in a sodium bromide-sodium tetraborate medium of pH 8.6, with amperometric end-point detection. Parameters affecting the pretreatment procedure were evaluated. The optimized conditions included the heating of 2 g of urea at around 300°C for 2 h with 10 cm(3) of sulfuric acid. Under the proposed conditions, the assay value with expanded uncertainty (k = 2), 99.870 ± 0.026%, agreed well with the certified value of NIST SRM 912a urea, 99.9 ± 0.1%. PMID:23842420

Kato, Jun; Koseki, Takuma; Aoki, Yukie; Yamada, Ayako; Tanaka, Tatsuhiko

2013-01-01

259

Perfluoroalkyl chemicals and elevated serum uric acid in US adults  

PubMed Central

Background: Perfluoroalkyl chemicals, including perfluorooctanoic acid and perfluorooctane sulfonate, are man-made chemicals that have been detected in the blood of over 98% of the US population. Serum uric acid is a novel biomarker, even mild elevations of which has been implicated in the development of hypertension, diabetes mellitus, cardiovascular disease, and chronic kidney disease. We examined the relationship of serum perfluoroalkyl chemicals, including perfluorooctanoic acid and perfluorooctane sulfonate, and elevated uric acid levels in a representative sample of US adults. Methods: We examined 3883 participants from the 1999–2000 and 2003–2006 National Health and Nutritional Examination Surveys, a representative, multiethnic population-based survey of noninstitutionalized US adults. Serum perfluorooctanoic acid and perfluorooctane sulfonate were analyzed as quartiles. The main outcome was hyperuricemia. Results: We found that serum levels of perfluoroalkyl chemicals, including perfluorooctanoic acid and perfluorooctane sulfonate, were positively associated with hyperuricemia. This association appeared to be independent of confounders such as age, gender, race-ethnicity, body mass index, diabetes, hypertension, and serum cholesterol. Compared with subjects in quartile 1 (referent), the multivariate odds ratio for hyperuricemia among subjects in quartile 4 was 1.97 (95% confidence interval 1.44–2.70, P < 0.0001) for perfluorooctanoic acid and 1.48% (95% confidence interval 0.99–2.22, P = 0.0433) for perfluorooctane sulfonate. This observed association persisted in subgroup analysis by gender and body mass index. Conclusion: Our results demonstrate that elevated levels of perfluoroalkyl chemicals are associated with hyperuricemia even at low perfluoroalkyl chemical exposure levels as seen in the US general population.

Shankar, Anoop; Xiao, Jie; Ducatman, Alan

2011-01-01

260

Detection of Interstellar Urea with Carma  

NASA Astrophysics Data System (ADS)

Urea, a molecule discovered in human urine by H. M. Rouelle in 1773, has a significant role in prebiotic chemistry. Previous BIMA observations have suggested that interstellar urea [(NH_2)_2CO] is a compact hot core molecule such as other large molecules, e.g. methyl formate and acetic acid (2009, 64th OSU Symposium On Molecular Spectroscopy, WI05). We have conducted an extensive search for urea toward the high mass hot molecular core Sgr B2(N-LMH) using CARMA and the IRAM 30 m. Because the spectral lines of heavy molecules like urea tend to be weak and hot cores display lines from a wide range of molecules, a major problem in identifying urea lines is confusion with lines of other molecules. Therefore, it is necessary to detect a number of urea lines and apply sophisticated statistical tests before having confidence in an identification. The 1 mm resolution of CARMA enables favorable coupling of the source size and synthesized beam size, which was found to be essential for the detection of weak signals. The 2.5^"×2^" synthesized beam of CARMA significantly resolves out the contamination by extended emission and reveals the eight weak urea lines that were previously blended with nearby transitions. Our analysis indicates that these lines are likely to be urea since the resulting observed line frequencies are coincident with a set of overlapping connecting urea lines, and the observed line intensities are consistent with the expected line strengths of urea. In addition, we have developed a new statistical approach to examine the spatial correlation between the observed lines by applying the Student T-test to the high resolution channel maps obtained from CARMA. The T-test shows similar spatial distributions from all eight candidate lines, suggesting a common molecular origin, urea. Our T-test method could have a broad impact on the next generation of arrays, such as ALMA, because the new arrays will require a method to systematically determine the credibility of detections of weaker signals from new and larger interstellar molecules.

Kuo, H.-L.; Snyder, L. E.; Friedel, D. N.; Looney, L. W.; McCall, B. J.; Remijan, A. J.; Lovas, F. J.; Hollis, J. M.

2010-06-01

261

A stable three enzyme creatinine biosensor. 2. Analysis of the impact of silver ions on creatine amidinohydrolase  

Microsoft Academic Search

The enzyme creatine amidinohydrolase is a clinically important enzyme used in the determination of creatinine in blood and urine. Continuous use biosensors are becoming more important in the clinical setting; however, long-use creatinine biosensors have not been commercialized due to the complexity of the three-enzyme creatinine biosensor and the lack of stability of its components. This paper, the second in

Jason A. Berberich; Lee Wei Yang; Ivet Bahar; Alan J. Russell

2005-01-01

262

The role of creatinine and histidine in Benedict's qualitative test for reducing sugar in urine  

PubMed Central

The statement made in some standard textbooks that Benedict's qualitative test gives a green, yellow, or orange-red precipitate with pure solutions of glucose of varying strength has been shown to be incorrect. Pure solutions of glucose give only a bright red precipitate at all concentrations. These changes in the colour of the suspensions are observed with urinary glucose only. The difference in the action of glucose in water and in urine has been shown to be mostly due to creatinine and to a small extent to the histidine content of urine. The colour of the precipitate depends not only on the concentration of glucose but also on that of creatinine. An increase in concentration of creatinine tends to make the precipitate more yellow. Histidine has a similar though much smaller effect. Attention has been drawn to possible errors in the semi-quantitative assay of urinary glucose by Benedict's test arising out of variation in concentration of creatinine and histidine.

Sur, B. K.; Shukla, R. K.; Agashe, V. S.

1972-01-01

263

ESTIMATES OF AGE-SPECIFIC URINARY EXCRETION RATES FOR CREATININE AMONG CHILDREN  

EPA Science Inventory

The results of this study suggest that naïve adjustment by creatinine concentration, without consideration of the age-dependence of the physiological mechanisms controlling its excretion, may introduce sizeable error and is inappropriate when comparing metabolite concentrations a...

264

EVALUATION OF DISPOSABLE DIAPERS FOR QUANTATIVE MEASUREMENTS OF PESTICIDE METABOLITES AND CREATININE IN URINE SAMPLES  

EPA Science Inventory

This project consisted of a laboratory study to evaluate an extraction and analysis method for quantifying biomarkers of pesticide exposure and creatinine in urine samples collected with commercially-available disposable diapers. For large exposure studies, such as the National ...

265

The clinical application of a urine albumin:creatinine ratio point-of-care device  

Microsoft Academic Search

Introduction: Microalbuminuria is an accepted predictive marker for the early detection of renal disease and the identification of patients at high risk of developing complications of diabetes and hypertension. The Bayer Clinitek 50 is a urine chemistry point-of-care analyser for the semi-quantitative measurement of albumin and creatinine and calculation of albumin:creatinine ratio (ACR). Method: Urine samples were obtained from 252

Bernard L Croal; W. J Mutch; B. M Clark; A Dickie; J Church; D Noble; I. S Ross

2001-01-01

266

The marker of cobalamin deficiency, plasma methylmalonic acid, correlates to plasma creatinine  

Microsoft Academic Search

Abstract. Hvas AM, Juul S, Gerdes LU, Nexø E (Aarhus University and Aarhus University Hospital, Aarhus, Denmark). The marker of cobalamin deficiency, plasma methylmalonic acid, correlates to plasma,creatinine. J Intern Med 2000; 247: 507? 512. Objective. To examine,the relationship between,the two diagnostic tests, plasma methylmalonic acid and plasma cobalamins, and their association with plasma creatinine, age and sex. Design.,Cross-sectional study,of

A. M. Hvas; S. Juul; L. U. Gerdes; E. Nexo

2000-01-01

267

An enzymeless electrochemical sensor for the selective determination of creatinine in human urine  

Microsoft Academic Search

Determination of creatinine in various biological fluids is useful for evaluation of renal, muscular and thyroid dysfunctions. An enzymeless electrochemical approach for the selective and quantitative recognition of creatinine in human urine has been demonstrated by using a preanodized screen-printed carbon electrode (SPE*). During a preconcentration step (at 1.8V versus Ag\\/AgCl), the formation of a stable carbon–carbon bond between the

J.-C. Chen; A. S. Kumar; H.-H. Chung; S.-H. Chien; M.-C. Kuo; J.-M. Zen

2006-01-01

268

Urine albumin to creatinine ratio-response to exercise in diabetes  

Microsoft Academic Search

Albuminuria was studied in 40 diabetic children before and after a standardised exercise test, and also in 21 normal children; the results are expressed as geometric mean (95% range) of urine albumin:urine creatinine ratio (mg\\/mg). There was no significant difference between the mean resting albumin:creatinine ratio in the two groups, or between these ratios before and after exercise in the

I G Jefferson; S A Greene; M A Smith; R F Smith; N K Griffin; J D Baum

1985-01-01

269

Prediction of glomerular filtration rate from serum creatinine concentration in advanced chronic renal failure  

Microsoft Academic Search

Prediction of glomerular filtration rate from serum creatinine concentration in advanced chronic renal failure. In 85 patients with established chronic renal failure, as manifested by serum creatinine concentration ([Cr]) > 0.177 mM (> 2 mg\\/dl), urinary clearance of 99mTc-DTPA (GFR) and [Cr] were determined one to four times and averaged. GFR was expressed per 3 m2 of height2 rather than

Mackenzie Walser; Helen H Drew; Joanna L Guldan

1993-01-01

270

Variation in the serum creatinine assay calibration: A practical application to glomerular filtration rate estimation  

Microsoft Academic Search

Variation in the serum creatinine assay calibration: A practical application to glomerular filtration rate estimation.BackgroundVariation among clinical laboratories in calibration of serum creatinine assays is a source of error in glomerular filtration rate (GFR) estimation equations. We evaluated impact of this variation on GFR estimates.MethodsErrors in GFR estimates were computed based on the range of calibration differences from the 1994

KALYANI MURTHY; LESLEY A STEVENS; PAUL C STARK; ANDREW S LEVEY

2005-01-01

271

Evaluation of Trial Outcomes in Acute Kidney Injury by Creatinine Modeling  

PubMed Central

Background and objectives: Clinical trials of acute kidney injury (AKI) use changes in creatinine as outcome metrics. This study investigated how outcome metrics and baseline creatinine affect trial outcome. Design, setting, participants, & measurements: A one-compartment pharmacokinetic model of creatinine change resulting from a decrease in GFR was applied to a population of 10,000 simulated virtual inpatients. Treatment was simulated as an amelioration of GFR decrease by a specified percentage, the treatment efficacy, in 50%. Three categorical and two continuous outcome metrics were calculated and compared. Outcomes were compared for measured and estimated baseline creatinine levels that were back-calculated assuming a GFR of 100 or 75 ml/min. Results: The continuous metrics, the average value of creatinine and the average value of creatinine relative to baseline decreased approximately linearly with increase in treatment efficacy. The categorical metrics displayed a sigmoidal decrease and erroneously suggested perfect treatment when GFR decrease was ameliorated by only 60 to 80%. Using an estimate of baseline creatinine increased the number of patients who were classified as having AKI. Conclusions: When used to determine clinical trial outcome, continuous metrics correctly detected the extent of intervention. At low treatment efficacy, categorical metrics underestimated and at high treatment efficacy overestimated the effect of treatment. These effects were exaggerated when the population contained a high proportion of patients with more severe AKI. An estimated baseline creatinine level will overestimate AKI prevalence compared with a measured baseline value. Clinical trials of AKI should use a continuous outcome metric and a measured baseline and report baseline median and interquartile range.

Frampton, Christopher M.; Endre, Zoltan H.

2009-01-01

272

Seasonal levels of minerals, enzymes, nutrients and metabolic products in plasma of intact and castrated adult male white-tailed deer (Odocoileus virginianus).  

PubMed

1. Alkaline phosphatase (AP), cholesterol, creatinine, uric acid, total protein, albumin, bilirubin, urea nitrogen, calcium, glucose, lactic dehydrogenase (LDH) and serum glutamic-oxalacetic transaminase (SGOT) were measured in the plasma of three intact and three castrated male deer. 2. A statistically significant seasonal cycle of AP, cholesterol, creatinine and uric acid was found in intact but not in castrated animals. 3. Monthly levels of total protein, albumin, urea nitrogen, bilirubin and calcium were significantly higher in castrated deer. 4. On the other hand, monthly levels of LDH and SGOT were higher in intact animals. PMID:6130880

Morris, J M; Bubenik, G A

1983-01-01

273

Renal clearance of pancreatic and salivary amylase relative to creatinine in patients with chronic renal insufficiency.  

PubMed Central

Pancreatic and salivary amylase/creatinine clearance ratios in patients with various degrees of renal impairment were compared with those obtained for control subjects. In chronic renal insufficiency (mean GFR 30 ml/min +/- 15 SD; n = 13) the clearance ratios for pancreatic (mean 3.5 +/- 1.85 SD) and salivary (mean 2.3 +/- 1.3 SD) amylase were significantly higher (P less than 0.05) than those in controls. Corresponding control values (n = 26) were 2.64 +/- 0.86 (pancreatic) and 1.64 +/- 0.95 (salivary). Three patients showed values above the normal limit. In the diabetic group (mean GFR 41 ml/min +/- 22 SD; n = 10) salivary amylase/creatinine clearance ratios (mean 2.36 +/- 1.55 SD) were significantly higher than in controls (P less than 0.05). Three patients showed raised values. Pancreatic amylase clearance was raised in only one of these patients. Three patients with terminal disease (mean GFR 10 ml/min) showed markedly raised (two- to threefold) clearance ratios for both salivary and pancreatic amylase. Of a total of 26 patients, eight had increased total amylase/creatinine clearance ratios. Pancreatic amylase/creatinine clearance was increased in seven patients, while nine patients showed raised salivary amylase/creatinine ratios. Patients with raised clearance ratios did not have clinical evidence of pancreatitis. We suggest that, in the presence of impaired renal function, a high amylase/creatinine clearance ratio need not be indicative of pancreatic disease.

Keogh, J B; McGeeney, K F; Drury, M I; Counihan, T B; O'Donnell, M D

1978-01-01

274

N-Acetylcysteine Effect on Serum Creatinine and Cystatin C Levels in CKD Patients  

PubMed Central

Background and objectives: N-acetylcysteine (NAC) has been widely used as a prophylactic therapy for contrast-induced nephropathy (CIN). Its efficacy is controversial because of heterogeneity in study results and because of evidence that NAC can alter serum creatinine levels without affecting glomerular filtration rate. This confounding effect of N-acetylcysteine on serum creatinine has not been rigorously tested, however, in a population at risk for CIN and following doses of NAC currently recommended for prophylaxis of CIN. Design, setting, participants, & measurements: “Double-dose” NAC was administered in the absence of iodinated contrast media to 29 stage 3 to 5 stable chronic kidney disease patients. Serum creatinine and cystatin C were measured before and 4 h and 48 h after the last dose of NAC. Results: There was no effect of NAC on either serum creatinine or cystatin C levels. Conclusion: NAC, in doses currently recommended for prophylaxis of CIN, has no effect on serum creatinine or cystatin C levels. It is therefore unlikely that the heterogeneity seen in clinical trials of NAC prophylaxis for CIN is related to a confounding effect on serum creatinine.

Rehman, Tariq; Fought, Jason; Solomon, Richard

2008-01-01

275

Random Urinary Calcium/Creatinine Ratio for Screening Hypercalciuria in Children with Hematuria  

PubMed Central

Background Hypercalciuria is one of the most common causes of unexplained isolated hematuria. The diagnostic methods for hypercalciuria have not yet been standardized. The aim of this study was to assess whether random urinary calcium/creatinine ratio could be used as a screening tool for hypercalciuria in children with hematuria. Methods This prospective study included 264 children with primary hematuria for whom both random and 24 hr urinary evaluations were performed. Pearson correlation and ROC curve were used to assess the correlations. A multiple linear regression model was used to analyze effects of age, weight, height, body mass index, and body surface area on random urinary calcium/creatinine ratio. Results There was a moderately strong correlation between random urinary calcium/creatinine ratio and 24 hr urinary calcium excretion (r=0.584, P<0.001). The most appropriate cutoff value of random urinary calcium/creatinine ratio for the estimation of hypercalciuria was 0.075 mg/mg (sensitivity, 77.8%; specificity, 64.3%; area under the curve, 0.778). Body mass index and 24 hr urinary calcium excretion significantly affected random urinary calcium/creatinine ratio with a low coefficient of determination (r2=0.380, P<0.001). Conclusions Random urinary calcium/creatinine ratio is not suitable for screening hypercalciuria in children with hematuria. Twenty-four hour urinary analysis should be performed to diagnose hypercalciuria in children with hematuria.

Choi, In Su; Jung, Eui Seok; Choi, Young Earl; Cho, Young Kuk; Kim, Chan Jong

2013-01-01

276

Serum uric acid is a GFR-independent long-term predictor of acute and chronic renal insufficiency: the Jerusalem Lipid Research Clinic cohort study  

PubMed Central

Background. Kidney disease is commonly accompanied by hyperuricemia. However, the contribution of serum uric acid (SUA) to kidney injury is debated. Our objective was to assess the long-term prediction of renal failure by SUA. Methods. Visit 2 participants in the Jerusalem Lipid Research Clinic cohort with normal baseline kidney function were followed for 24–28 years. SUA levels were assessed for associations with acute renal failure (ARF) and chronic renal failure (CRF) as defined by hospital discharge records, and mortality, ascertained through linkage with the national population registry. Results. Among 2449 eligible participants (1470 men, 979 women aged 35–78 years in 1976–79), SUA was positively linked with male sex, serum creatinine and components of the metabolic syndrome but was lower in smokers and in diabetic subjects. The 22- to 25-year incidence of hospital-diagnosed kidney failure (145 first events, 67% CRF) and the 24- to 28-year mortality (587 events) were higher in subject with hyperuricemia (>6.5 mg/dL in men and >5.3 mg/dL in women, reflecting the upper quintiles), independent of baseline kidney function and covariates. Hyperuricemia conferred adjusted hazard ratios of 1.36 (P = 0.003), 2.14 (P < 0.001) and 2.87 (P = 0.003) for mortality, CRF and ARF, respectively. Conclusions. SUA predicts renal failure incidence and all-cause mortality independently of demographic and clinical covariates. These results lend support to the undertaking of clinical trials to examine the effect of uric acid-lowering strategies on kidney outcomes.

Kark, Jeremy D.

2011-01-01

277

Discovery of 1-oxa-4,9-diazaspiro[5.5]undecane-based trisubstituted urea derivatives as highly potent soluble epoxide hydrolase inhibitors and orally active drug candidates for treating of chronic kidney diseases.  

PubMed

We identified 1-oxa-4,9-diazaspiro[5.5]undecane-based trisubstituted ureas as highly potent soluble epoxide hydrolase (sEH) inhibitors and orally active agents for treating chronic kidney diseases. Compound 19 exhibited excellent sEH inhibitory activity and bioavailability. When administered orally at 30 mg/kg, 19 lowered serum creatinine in a rat model of anti-glomerular basement membrane glomerulonephritis but 2,8-diazaspiro[4.5]decane-based trisubstituted ureas did not. These results suggest that 19 is an orally active drug candidate for treating chronic kidney diseases. PMID:24373724

Kato, Yuko; Fuchi, Nobuhiro; Nishimura, Yutaka; Watanabe, Ayano; Yagi, Mai; Nakadera, Yasuhito; Higashi, Eriko; Yamada, Masateru; Aoki, Takumi; Kigoshi, Hideo

2014-01-15

278

The Effect of Rate of Gland Function on Parotid Fluid Uric Acid Levels.  

National Technical Information Service (NTIS)

Paired parotid fluid samples were collected without exogenous stimulation and at 5 different gustation-induced rates of flow. Enzymatic uric acid analyses were carried out to ascertain which of the collection procedures was least susceptible to the effect...

H. H. Chauncey I. L. Shannon

1967-01-01

279

Synthesis of positively charged CdTe quantum dots and detection for uric acid  

NASA Astrophysics Data System (ADS)

The CdTe dots (QDs) coated with 2-Mercaptoethylamine was prepared in aqueous solution and characterized with fluorescence spectroscopy, UV-Vis absorption spectra, high-resolution transmission electron microscopy and infrared spectroscopy. When the ?ex = 350 nm, the fluorescence peak of positively charged CdTe quantum dots is at 592 nm. The uric acid is able to quench their fluorescence. Under optimum conditions, the change of fluorescence intensity is linearly proportional to the concentration of uric acid in the range 0.4000-3.600 ?mol L -1, and the limit of detection calculated according to IUPAC definitions is 0.1030 ?mol L -1. Compared with routine method, the present method determines uric acid in human serum with satisfactory results. The mechanism of this strategy is due to the interaction of the tautomeric keto/hydroxyl group of uric acid and the amino group coated at the CdTe QDs.

Zhang, Tiliang; Sun, Xiangying; Liu, Bin

2011-09-01

280

Plasma Uric Acid Levels Correlate with Inflammation and Disease Severity in Malian Children with Plasmodium falciparum Malaria  

PubMed Central

Background Plasmodium falciparum elicits host inflammatory responses that cause the symptoms and severe manifestations of malaria. One proposed mechanism involves formation of immunostimulatory uric acid (UA) precipitates, which are released from sequestered schizonts into microvessels. Another involves hypoxanthine and xanthine, which accumulate in parasitized red blood cells (RBCs) and may be converted by plasma xanthine oxidase to UA at schizont rupture. These two forms of ‘parasite-derived’ UA stimulate immune cells to produce inflammatory cytokines in vitro. Methods and Findings We measured plasma levels of soluble UA and inflammatory cytokines and chemokines (IL-6, IL-10, sTNFRII, MCP-1, IL-8, TNF?, IP-10, IFN?, GM-CSF, IL-1?) in 470 Malian children presenting with uncomplicated malaria (UM), non-cerebral severe malaria (NCSM) or cerebral malaria (CM). UA levels were elevated in children with NCSM (median 5.74 mg/dl, 1.21-fold increase, 95% CI 1.09–1.35, n?=?23, p?=?0.0007) and CM (median 5.69 mg/dl, 1.19-fold increase, 95% CI 0.97–1.41, n?=?9, p?=?0.0890) compared to those with UM (median 4.60 mg/dl, n?=?438). In children with UM, parasite density and plasma creatinine levels correlated with UA levels. These UA levels correlated with the levels of seven cytokines [IL-6 (r?=?0.259, p<0.00001), IL-10 (r?=?0.242, p<0.00001), sTNFRII (r?=?0.221, p<0.00001), MCP-1 (r?=?0.220, p<0.00001), IL-8 (r?=?0.147, p?=?0.002), TNF? (r?=?0.132, p?=?0.006) and IP-10 (r?=?0.120, p?=?0.012)]. In 39 children, UA levels were 1.49-fold (95% CI 1.34–1.65; p<0.0001) higher during their malaria episode [geometric mean titer (GMT) 4.67 mg/dl] than when they were previously healthy and aparasitemic (GMT 3.14 mg/dl). Conclusions Elevated UA levels may contribute to the pathogenesis of P. falciparum malaria by activating immune cells to produce inflammatory cytokines. While this study cannot identify the cause of elevated UA levels, their association with parasite density and creatinine levels suggest that parasite-derived UA and renal function may be involved. Defining pathogenic roles for parasite-derived UA precipitates, which we have not directly studied here, requires further investigation. Trial Registration ClinicalTrials.gov NCT00669084

Lopera-Mesa, Tatiana M.; Mita-Mendoza, Neida K.; van de Hoef, Diana L.; Doumbia, Saibou; Konate, Drissa; Doumbouya, Mory; Gu, Wenjuan; Traore, Karim; Diakite, Seidina A. S.; Remaley, Alan T.; Anderson, Jennifer M.; Rodriguez, Ana; Fay, Michael P.; Long, Carole A.; Diakite, Mahamadou; Fairhurst, Rick M.

2012-01-01

281

Highly sensitive and selective uric acid biosensor based on RF sputtered NiO thin film  

Microsoft Academic Search

Present study highlights the importance of RF sputtered NiO thin film deposited on platinum coated glass substrate (NiO\\/Pt\\/Ti\\/glass) as a potential matrix for the realization of highly sensitive and selective uric acid biosensor. Uricase has been immobilized successfully onto the surface of NiO matrix by physical adsorption technique. The prepared bioelectrode (uricase\\/NiO\\/Pt\\/Ti\\/glass) is utilized for sensing uric acid using the

Kashima Arora; Monika Tomar; Vinay Gupta

2011-01-01

282

Amperometric uric acid biosensors fabricated of various types of uricase enzymes  

Microsoft Academic Search

Preparation process of an enzyme-based bipotentiostatic amperometric uric acid sensor has been investigated. The suitability of three different Uricase (EC 1.7.3.3) enzymes (from porcine liver, Candida Utilis, Bacillus Fastidiosus) is described in this paper. The sensor fabricated of Uricase from Candida Utilis showed a linear response to uric acid in the 0-0.9 mM concentration range and the response current range

Hunor Sántha; Róbert Dobay; Gábor Harsányi

2003-01-01

283

Hypothesis: Uric acid, nephron number, and the pathogenesis of essential hypertension  

Microsoft Academic Search

Hypothesis: Uric acid, nephron number, and the pathogenesis of essential hypertension.BackgroundEssential hypertension affects more than 25% of the world's population. Genetic, physiologic, and epidemiologic studies provide clues to its origins, but a clear understanding has been elusive. Recent experimental and clinical studies have implicated uric acid in the onset of essential hypertension.MethodsIn a retrospective chart review, we identified 95 children

Daniel I. Feig; TAKAHIKO NAKAGAWA; S. Ananth Karumanchi; William J. Oliver; DUK-HEE KANG; JENNIFER FINCH; Richard J. Johnson

2004-01-01

284

Uric Acid Spherulites in the Reflector Layer of Firefly Light Organ  

PubMed Central

Background In firefly light organs, reflector layer is a specialized tissue which is believed to play a key role for increasing the bioluminescence intensity through reflection. However, the nature of this unique tissue remains elusive. In this report, we investigated the role, fine structure and nature of the reflector layer in the light organ of adult Luciola cerata. Principal Findings Our results indicated that the reflector layer is capable of reflecting bioluminescence, and contains abundant uric acid. Electron microscopy (EM) demonstrated that the cytosol of the reflector layer's cells is filled with densely packed spherical granules, which should be the uric acid granules. These granules are highly regular in size (?700 nm in diameter), and exhibit a radial internal structure. X-ray diffraction (XRD) analyses revealed that an intense single peak pattern with a d-spacing value of 0.320 nm is specifically detected in the light organ, and is highly similar to the diffraction peak pattern and d-spacing value of needle-formed crystals of monosodium urate monohydrate. However, the molar ratio evaluation of uric acid to various cations (K+, Na+, Ca2+ and Mg2+) in the light organ deduced that only a few uric acid molecules were in the form of urate salts. Thus, non-salt uric acid should be the source of the diffraction signal detected in the light organ. Conclusions In the light organ, the intense single peak diffraction signal might come from a unique needle-like uric acid form, which is different from other known structures of non-salt uric acid form. The finding of a radial structure in the granules of reflector layer implies that the spherical uric acid granules might be formed by the radial arrangement of needle-formed packing matter.

Goh, King-Siang; Sheu, Hwo-Shuenn; Hua, Tzu-En; Kang, Mei-Hua; Li, Chia-Wei

2013-01-01

285

Benfotiamine attenuates nicotine and uric acid-induced vascular endothelial dysfunction in the rat  

Microsoft Academic Search

The study has been designed to investigate the effect of benfotiamine, a thiamine derivative, in nicotine and uric acid-induced vascular endothelial dysfunction (VED) in rats. Nicotine (2mgkg?1day?1, i.p., 4 weeks) and uric acid (150mgkg?1day?1, i.p., 3 weeks) were administered to produce VED in rats. The development of VED was assessed by employing isolated aortic ring preparation and estimating serum and

Pitchai Balakumar; Ramica Sharma; Manjeet Singh

2008-01-01

286

A new approach for noninvasive transdermal determination of blood uric acid levels  

PubMed Central

The aims of this study were to investigate the most effective combination of physical forces from laser, electroporation, and reverse iontophoresis for noninvasive transdermal extraction of uric acid, and to develop a highly sensitive uric acid biosensor (UAB) for quantifying the uric acid extracted. It is believed that the combination of these physical forces has additional benefits for extraction of molecules other than uric acid from human skin. A diffusion cell with porcine skin was used to investigate the most effective combination of these physical forces. UABs coated with ZnO2 nanoparticles and constructed in an array configuration were developed in this study. The results showed that a combination of laser (0.7 W), electroporation (100 V/cm2), and reverse iontophoresis (0.5 mA/cm2) was the most effective and significantly enhanced transdermal extraction of uric acid. A custom-designed UAB coated with ZnO2 nanoparticles and constructed in a 1×3 array configuration (UAB-1×3-ZnO2) demonstrated enough sensitivity (9.4 ?A/mM) for quantifying uric acid extracted by the combined physical forces of laser, electroporation, and RI. A good linear relationship (R2=0.894) was demonstrated to exist between the concentration of uric acid (0.2–0.8 mM) inside the diffusion cell and the current response of the UAB-1×3-ZnO2. In conclusion, a new approach to noninvasive transdermal extraction and quantification of uric acid has been established.

Ching, Congo Tak-Shing; Yong, Kok-Khun; Yao, Yan-Dong; Shen, Huan-Ting; Hsieh, Shiu-Man; Jheng, Deng-Yun; Sun, Tai-Ping; Shieh, Hsiu-Li

2014-01-01

287

The Relationship between Serum Uric Acid and Spirometric Values in Participants in a Health Check: The Takahata Study  

PubMed Central

Background: Tissue hypoxia induces the degradation of adenosine triphosphate, resulting in the production of uric acid (UA). Patients with chronic obstructive pulmonary disease (COPD) have been reported to have high serum levels of UA (sUA), compared with control subjects. However, the relationship between sUA levels and spirometric measures has not been investigated in detail in a general population. Methods: Subjects aged 40 years or older (n = 2,917), who had participated in a community-based annual health check in Takahata, Japan, in 2004 and 2005, were enrolled in the study. These subjects performed spirometry, their blood pressure was measured, and a blood sample was taken. Results: sUA levels were significantly higher in males than in females. Percent predicted forced vital capacity [FVC %predicted] (r = -0.13) and forced expiratory volume in 1 s [FEV1 %predicted] (r = -0.118) were inversely correlated with sUA levels in females but not in males. Univariate regression analysis indicated that age, body mass index (BMI), ethanol intake, mean blood pressure (BP), and serum creatinine (sCr) were significantly associated with sUA levels in males. In females, age, BMI, mean BP, hemoglobin A1c, sCr, FVC %predicted, and FEV1 %predicted were significantly associated with sUA levels. Multiple linear regression analysis showed that for both genders, FVC %predicted and FEV1 %predicted were predictive for sUA levels, independently of the other clinical parameters. Subjects with lung restriction had higher sUA levels than subjects without lung restriction. In addition, subjects with moderate and severe airflow limitation had higher sUA levels than subjects without airflow limitation or those with mild airflow limitation. Conclusion: FVC %predicted and FEV1 %predicted were significantly associated with sUA levels in a general population.

Aida, Yasuko; Shibata, Yoko; Osaka, Daisuke; Abe, Shuichi; Inoue, Sumito; Fukuzaki, Koji; Tokairin, Yoshikane; Igarashi, Akira; Yamauchi, Keiko; Nemoto, Takako; Nunomiya, Keiko; Kishi, Hiroyuki; Sato, Masamichi; Watanabe, Tetsu; Konta, Tsuneo; Kawata, Sumio; Kato, Takeo; Kubota, Isao

2011-01-01

288

Urea handling by the medullary collecting duct of the rat kidney during hydropenia and urea infusion  

Microsoft Academic Search

Previous micropuncture studies of distal tubule fluid and ureteral urine have indicated a varying degree of urea reabsorption in the collecting duct. In the present experiments the microcatheterization technique was used to directly determine urea, Na, K, total solute and fluid reabsorption along the length of the medullary collecting duct in anaesthetized hydropenic rats and in rats given low dose

H. Sonnenberg; D. R. Wilson

1981-01-01

289

Urea release rate from a scoop of coated pure urea beads: Unified extreme analysis  

Microsoft Academic Search

Urea release from a scoop of coated beads in a given volume of a well stirred liquid has been investigated analytically and experimentally. A method for determining the fractional cumulative release and fractional release rate curves for the scoop without knowing particle number and radii is presented. The representative D\\/Kb for a scoop of urea beads spray coated with ethyl

S. M. Lu; Szu-Lin Chang; Wen-Yu Ku; Hou-Chien Chang; Jiunn-Yau Wang; Duu-Jong Lee

2007-01-01

290

Serum uric acid: an early indicator of oxidative stress in beta thalassemia population.  

PubMed

Iron induced alteration in the redox balance is a major complication in the beta thalassemia major patients receiving regular blood transfusion. Variable degrees of association between uric acid level with the free iron and its storage form ferritin in thalassemic patients are suggested to play a significant role in this alteration by an unclear mechanism. In the present study, we made an effort to analyze the association of serum uric acid with oxidative stress and to evaluate the predictive value of serum iron, serum ferritin and serum uric acid level on oxidative stress induced lipid peroxidation in beta thalassemic patients. For this we assayed these parameters in 61 patients of ? thalassemia major and 51 age and sex matched controls of a rural area of West Bengal. Serum TBARS, serum Uric acid, serum Ferritin and serum Iron levels were significantly higher in the patient group (p<0.001 for all of them). Significant correlations existed between serum levels of TBARS, Uric acid, Ferritin and Iron levels in the patient group whereas only serum TBARS levels showed significant correlation with serum iron level in the control group. Regression analysis revealed that uric acid levels have a better predictive value (?=0.3, p=0.001) than serum ferritin value (?=0.013, p=0.871) for indicating TBARS production. PMID:23982550

Dasgupta, S; Dasgupta, A; Mukhopadhayay, T; Bhattacharya, S; Swaika, B; Banarjee, U; Chakrabarty, P

2013-07-01

291

The Role of Uric Acid as an Endogenous Danger Signal in Immunity and Inflammation  

PubMed Central

Gout is an ancient disease that still plagues us. Its pathogenic culprit, uric acid crystal deposition in tissues, is a strong inflammatory stimulant. In recent years, the mechanisms through which uric acid crystals promote inflammation have been a subject of increasing interest among rheumatologists and immunologists. Uric acid has been identified as an endogenous adjuvant that drives immune responses in the absence of microbial stimulation. Because uric acid is a ubiquitous metabolite that is produced in high quantities upon cellular injury, the ramifications of its effects may be considerable in health and in disease. Uric acid crystals also have been shown to trigger interleukin-1?–mediated inflammation via activation of the NOD-like receptor protein (NLRP)3 inflammasome, a multimolecular complex whose activation appears to be central to many pathological inflammatory conditions. In this article, we review the possible mechanisms of uric acid–mediated inflammation and offer some historical perspectives on what has been learned about the complex effects of a relatively simple substance.

Ghaemi-Oskouie, Faranak

2011-01-01

292

Uric acid is a danger signal of increasing risk for osteoarthritis through inflammasome activation  

PubMed Central

Uric acid (UA) is known to activate the NLRP3 (Nacht, leucine-rich repeat and pyrin domain containing protein 3) inflammasome. When activated, the NLRP3 (also known as NALP3) inflammasome leads to the production of IL-18 and IL-1?. In this cohort of subjects with knee osteoarthritis (OA), synovial fluid uric acid was strongly correlated with synovial fluid IL-18 and IL-1?. Synovial fluid uric acid and IL-18 were strongly and positively associated with OA severity as measured by both radiograph and bone scintigraphy, and synovial fluid IL-1? was associated with OA severity but only by radiograph. Furthermore, synovial fluid IL-18 was associated with a 3-y change in OA severity, on the basis of the radiograph. We conclude that synovial fluid uric acid is a marker of knee OA severity. The correlation of synovial fluid uric acid with the two cytokines (IL-18 and IL-1?) known to be produced by uric acid-activated inflammasomes and the association of synovial fluid IL-18 with OA progression, lend strong support to the potential involvement of the innate immune system in OA pathology and OA progression.

Denoble, Anna E.; Huffman, Kim M.; Stabler, Thomas V.; Kelly, Susan J.; Hershfield, Michael S.; McDaniel, Gary E.; Coleman, R. Edward; Kraus, Virginia B.

2011-01-01

293

Association between serum uric acid level and diabetic peripheral neuropathy (A case control study).  

PubMed

Background: The role of uric acid is well known for the development of nephropathy and retinopathy in diabetic patients. The aim of this study was to evaluate the serum uric acid levels in patients with or without diabetic neuropathy (DPN). Methods: Forty-two patients with DPN (case group) and 42 patients without DPN (control group) matched with regard to age, gender, body mass index (BMI) and duration of their disease were entered into the study. The diagnosis of DPN was based on the nerve conduction studies on sural, peroneal and tibial nerves in lower limbs. Serum uric acid was measured in these two groups. Results: The mean age of the patients in the case group was 54.6±6.9 and in the control group was 55.8±5.8 years (p=0.389). The demographic characteristics of the patients in these two groups were equal, but only the history of diabetic foot ulcer was higher in patients with DPN (p<0.05). The mean serum uric acid was 4.70±0.96 in diabetic patients with DPN and 4.36±0.89 mg/dl in patients without DPN (p=0.019). Conclusion: The results show the higher level of serum uric acid level in diabetic patients with diabetic neuropathy. Further studies are required to determine the role of uric acid in the development and progression of DPN. PMID:24490008

Kiani, Javad; Habibi, Zahra; Tajziehchi, Ali; Moghimbeigi, Abbas; Dehghan, Arash; Azizkhani, Homeyra

2014-01-01

294

The Role of Uric Acid in Kidney Fibrosis: Experimental Evidences for the Causal Relationship  

PubMed Central

Hyperuricemia is a common finding in chronic kidney disease due to decreased uric acid clearance. The role of uric acid as a risk factor for chronic kidney disease has been largely debated, and recent studies suggested a role of uric acid in the causation and progression of kidney fibrosis, a final common pathway in chronic kidney disease. Uric acid and xanthine oxidase may contribute to kidney fibrosis mainly by inducing inflammation, endothelial dysfunction, oxidative stress, and activation of the renin-angiotensin system. Besides, hyperuricemia induces alterations in renal hemodynamics via afferent arteriolopathy and contributes to the onset and progression of kidney fibrosis. Xanthine oxidase inhibitors may prevent kidney damage via lowering uric acid and/or inhibiting xanthine oxidase. However, there is still no sufficient evidence from interventional clinical researches supporting the causal relationship between uric acid and kidney fibrosis. The effect and role of xanthine oxidase inhibitors in preventing kidney fibrosis and chronic kidney disease progression must be further explored by performing future large scale clinical trials.

Kim, Il Young; Lee, Dong Won; Kwak, Ihm Soo

2014-01-01

295

Serum uric acid and hypertension in adults: a paradoxical relationship in type 1 diabetes.  

PubMed

Adults with type 1 diabetes have lower serum uric acid levels compared with nondiabetic adults. Little is known about the relationship between serum uric acid and blood pressure in type 1 diabetes and whether it differs from the positive relationship found in nondiabetic adults. The authors assessed the cross-sectional and longitudinal relationships over 6 years between serum uric acid and blood pressure in adults with (35±9 years [n=393]) and without (38±9 years [n=685]) type 1 diabetes in the Coronary Artery Calcification in Type 1 Diabetes study. In nondiabetic adults, serum uric acid was associated with systolic blood pressure in multivariable models adjusted for cardiovascular risk factors. In adults with type 1 diabetes, a negative association was observed between serum uric acid and systolic blood pressure after multivariable adjustments. A positive association was observed between serum uric acid and systolic blood pressure in nondiabetic adults. In contrast, an inverse relationship was demonstrated after multivariable adjustments in type 1 diabetes. PMID:24667019

Bjornstad, Petter; Paul Wadwa, R; Sirota, Jeffrey C; Snell-Bergeon, Janet K; McFann, Kimberly; Rewers, Marian; Rivard, Christopher J; Jalal, Diana; Chonchol, Michel B; Johnson, Richard J; Maahs, David M

2014-04-01

296

Low uric acid levels in patients with Parkinson's disease: evidence from meta-analysis  

PubMed Central

Objective The association between Parkinson's disease (PD) and uric acid levels has gained intensive interest in recent years. We applied meta-analysis to investigate serum uric acid levels in patients with PD in comparison with healthy controls. Design We searched three electronic databases and reference lists up to January 2013. Two collaborators reviewed all the articles and data disagreement was resolved through discussion. Six studies met the eligibility criteria and were included in the meta-analysis of uric acid levels in patients with PD in comparison with controls. Participants 1217 patients with PD and 1276 matched healthy controls. Results The meta-analysis results showed that patients with PD had lower levels of uric acid than healthy controls (summary standardised mean difference (SMD)=?0.52, 95% CI (?0.72 to ?0.31)). Further gender subgroup analysis (summary SMD=?0.56, 95% CI (?0.72 to ?0.41) for women; summary SMD=?0.62, 95% CI (?0.94 to ?0.31) for men) indicated lower uric acid levels in patients with PD than healthy controls in women and men. Conclusions It was found that patients with PD had lower serum levels of uric acid than healthy controls and this association was more significant in men than in women. More efforts are encouraged to explore the prognostic and therapeutic implications for PD of the present findings.

Shen, Liang; Ji, Hong-Fang

2013-01-01

297

Uric Acid - Key Ingredient in the Recipe for Cardiorenal Metabolic Syndrome  

PubMed Central

Elevated serum uric acid levels are a frequent finding in persons with obesity, hypertension, cardiovascular and kidney disease as well as in those with the cardiorenal metabolic syndrome (CRS). The increased consumption of a fructose-rich Western diet has contributed to the increasing incidence of the CRS, obesity and diabetes especially in industrialized populations. There is also increasing evidence that supports a causal role of high dietary fructose driving elevations in uric acid in association with the CRS. Animal and epidemiological studies support the notion that elevated serum uric acid levels play an important role in promoting insulin resistance and hypertension and suggest potential pathophysiological mechanisms that contribute to the development of the CRS and associated cardiovascular disease and chronic kidney disease. To this point, elevated serum levels of uric acid appear to contribute to impaired nitric oxide production/endothelial dysfunction, increased vascular stiffness, inappropriate activation of the renin-angiotensin-aldosterone system, enhanced oxidative stress, and maladaptive immune and inflammatory responses. These abnormalities, in turn, promote vascular, cardiac and renal fibrosis as well as associated functional abnormalities. Small clinical trials have suggested that uric acid-lowering therapies may be beneficial in such patients; however, a consensus on the treatment of asymptomatic hyperuricemia is lacking. Larger randomized controlled trials need to be performed in order to critically evaluate the beneficial effect of lowering serum uric acid in patients with the CRS and those with diabetes and/or hypertension.

Chaudhary, Kunal; Malhotra, Kunal; Sowers, James; Aroor, Annayya

2013-01-01

298

Photothermal laser lithotripsy of uric acid calculi: clinical assessment of the effects of cyanide production  

NASA Astrophysics Data System (ADS)

The mechanism of holmium:YAG lithotripsy is photothermal. Holmium:YAG lithotripsy of uric acid calculi produces cyanide, which is a known, thermal decomposition produce of uric acid. we review our experience with holmium:YAG lithotripsy of uric acid to determine if there is any clinical evidence of cyanide toxicity. A retrospective analysis of all of our cases of holmium:YAG lithotripsy of uric acid calculi was done. Anesthetic and postoperative data were reviewed. A total of 18 patients with uric acid calculi were tread with holmium:YAG lithotripsy by urethroscopy (5), retrograde nephroscopy (2), percutaneous nephrolithotomy (5) or cystolithotripsy (6). Total holmium:YAG irradiation ranged from 1.2 to 331 kJ. No patient had evidence of increased end-tidal carbon dioxide, change sin electrocardiogram or significant decrease in postoperative serum bicarbonate. An 84 year old woman had decreased diastolic pressure of 30 mm Hg while under general anesthesia. No cyanide related neurologic, cardiac or respiratory complications were noted. These data suggest no significant cyanide toxicity from holmium:YAG lithotripsy or uric acid calculi in typical clinical settings. More specific studies in animals are warranted to characterize the risk.

Teichman, Joel M.; Champion, Paolo C.; Glickman, Randolph D.; Wollin, Tim A.; Denstedt, John D.

1999-06-01

299

Association between serum uric acid level and diabetic peripheral neuropathy (A case control study)  

PubMed Central

Background: The role of uric acid is well known for the development of nephropathy and retinopathy in diabetic patients. The aim of this study was to evaluate the serum uric acid levels in patients with or without diabetic neuropathy (DPN). Methods: Forty-two patients with DPN (case group) and 42 patients without DPN (control group) matched with regard to age, gender, body mass index (BMI) and duration of their disease were entered into the study. The diagnosis of DPN was based on the nerve conduction studies on sural, peroneal and tibial nerves in lower limbs. Serum uric acid was measured in these two groups. Results: The mean age of the patients in the case group was 54.6±6.9 and in the control group was 55.8±5.8 years (p=0.389). The demographic characteristics of the patients in these two groups were equal, but only the history of diabetic foot ulcer was higher in patients with DPN (p<0.05). The mean serum uric acid was 4.70±0.96 in diabetic patients with DPN and 4.36±0.89 mg/dl in patients without DPN (p=0.019). Conclusion: The results show the higher level of serum uric acid level in diabetic patients with diabetic neuropathy. Further studies are required to determine the role of uric acid in the development and progression of DPN.

Kiani, Javad; Habibi, Zahra; Tajziehchi, Ali; Moghimbeigi, Abbas; Dehghan, Arash; Azizkhani, Homeyra

2014-01-01

300

Plasmodium falciparum-Derived Uric Acid Precipitates Induce Maturation of Dendritic Cells  

PubMed Central

Malaria is characterized by cyclical fevers and high levels of inflammation, and while an early inflammatory response contributes to parasite clearance, excessive and persistent inflammation can lead to severe forms of the disease. Here, we show that Plasmodium falciparum-infected erythrocytes contain uric acid precipitates in the cytoplasm of the parasitophorous vacuole, which are released when erythrocytes rupture. Uric acid precipitates are highly inflammatory molecules that are considered a danger signal for innate immunity and are the causative agent in gout. We determined that P. falciparum-derived uric acid precipitates induce maturation of human dendritic cells, increasing the expression of cell surface co-stimulatory molecules such as CD80 and CD86, while decreasing human leukocyte antigen-DR expression. In accordance with this, uric acid accounts for a significant proportion of the total stimulatory activity induced by parasite-infected erythrocytes. Moreover, the identification of uric acid precipitates in P. falciparum- and P. vivax-infected erythrocytes obtained directly from malaria patients underscores the in vivo and clinical relevance of our findings. Altogether, our data implicate uric acid precipitates as a potentially important contributor to the innate immune response to Plasmodium infection and may provide a novel target for adjunct therapies.

van de Hoef, Diana L.; Coppens, Isabelle; Holowka, Thomas; Ben Mamoun, Choukri; Branch, OraLee; Rodriguez, Ana

2013-01-01

301

Variation in Serum Creatinine Level Is Correlated to Risk of Type 2 Diabetes  

PubMed Central

Background Skeletal muscle is well established as a major target organ of insulin action, and is associated with the pathogenesis of type 2 diabetes. Therefore, we attempted to determine whether a variation in serum creatinine is related to the development of type 2 diabetes and other risk factors for diabetes. Methods A total of 2,676 nondiabetic subjects with stable and normal renal function (estimated glomerular filtration rate >60 mL/min/1.73 m2) were followed up for approximately 4.5 years. New onset diabetes was defined as fasting plasma glucose (FPG) ?7.0 mmol/L, glycated hemoglobin (HbA1c) ?6.5%, or subjects taking antidiabetic agents. Variation of serum creatinine (?Cre) was defined as a difference between follow-up and baseline creatinine. In subgroup analysis, body composition was examined by bioelectric impedance analysis method. Results A total of 106 subjects were diagnosed with new-onset diabetes during the follow-up period. Baseline serum creatinine was not different between the new-onset diabetes and no diabetes groups. Negative ?Cre (?Cre <0) showed an association with increased risk of type 2 diabetes after adjusting for age, sex, body mass index, systolic blood pressure, FPG, HbA1c, triglyceride, high density lipoprotein cholesterol, and ?-glutamyl transpeptidase (odds ratio, 1.885; 95% confidence interval, 1.127 to 3.153). Serum creatinine level demonstrated positive correlation with muscle mass and negative correlation with percentage of body fat in body composition analysis. Conclusion Serum creatinine reflected body muscle mass and the decrease of serum creatinine might be regarded as a risk factor for type 2 diabetes.

Moon, Jun Sung

2013-01-01

302

High Prevalence of Stage 3 Chronic Kidney Disease in Older Adults Despite Normal Serum Creatinine  

PubMed Central

BACKGROUND Serum creatinine is commonly used to diagnose chronic kidney disease (CKD), but may underestimate CKD in older adults when compared with using glomerular filtration rates (eGFR). The magnitude of this underestimation is not clearly defined. OBJECTIVE Using the Modification of Diet in Renal Disease (MDRD) equation, to describe both the prevalence and the magnitude of underestimation of stage 3 CKD (GFR 30–59 ml/min/1.73 m2), as well as ideal serum creatinine cutoff values to diagnose stage 3 CKD among Americans ?65 years of age. DESIGN Cross-sectional. PARTICIPANTS A total of 3,406 participants ?65 years of age from the 1999–2004 National Health and Nutrition Examination Surveys (NHANES). MEASUREMENTS Serum creatinine levels were used to determine eGFR from the MDRD equation. Information on clinical conditions was self-reported. RESULTS Overall, 36.1% of older adults in the US have stage 3 or greater CKD as defined by eGFR values. Among older adults with stage 3 CKD, 80.6% had creatinine values ?1.5 mg/dl, and 38.6% had creatinine values ?1.2 mg/dl. Optimal cutoff values for serum creatinine in the diagnosis of stage 3 CKD in older adults were ?1.3 mg/dl for men and ?1.0 mg/dl for women, regardless of the presence or absence of hypertension, diabetes, or congestive heart failure. CONCLUSION Use of serum creatinine underestimates the presence of advanced (stage 3 or greater) CKD among older adults in the US. Automated eGFR reporting may improve the accuracy of risk stratification for older adults with CKD.

Vargas, Roberto B.; Kermah, Dulcie; Nissenson, Allen R.; Norris, Keith C.

2008-01-01

303

A perfusion study of the handling of urea and urea analogues by the gills of the dogfish shark (Squalus acanthias)  

PubMed Central

The branchial mechanism of urea retention in elasmobranchs was investigated using an in vitro isolated-perfused head preparation, as well as in vivo samples, in the spiny dogfish shark. Both in vivo and in control saline perfusions containing 350 mmol L?1 urea, calculated intracellular urea concentrations in gill epithelial cells were close to extracellular concentrations. Urea efflux to the external water fell only non-significantly, and calculated gill intracellular urea concentration did not change when perfusate urea concentration was reduced from 350 to 175 mmol?L?1 with osmotic compensation by 175 mmol L?1 mannitol. However, when the urea analogues thiourea or acetamide were present in the perfusate at concentrations equimolar (175 mmol L?1) to those of urea (175 mmol L?1), urea efflux rates were increased 4-fold and 6.5-fold respectively, and calculated gill intracellular urea concentrations were depressed by about 55%. Analogue efflux rates were similar to urea efflux rates. Previous studies have argued that either the basolateral or apical membranes provided the limiting permeability barrier, and/or that a back-transporter on the basolateral membranes of gill cells is responsible for urea retention. The present results provide new evidence that the apical membrane is the limiting factor in maintaining gill urea impermeability, and raise the prospect that a urea back-transporter, which can be competitively inhibited by thiourea and acetamide, operates at the apical membrane.

Liew, Hon Jung; De Boeck, Gudrun; Walsh, Patrick J.

2013-01-01

304

Quantitation of proteinuria using protein-creatinine ratio in random urine samples.  

PubMed

Estimation of proteinuria in children is cumbersome when a 24 h urine collection is needed. In the presence of a stable glomerular filtration rate, the ratio of urinary protein and creatinine should reflect the protein excretion. One hundred samples of urine (24 h and random samples) were collected from 50 children with nephrotic syndrome, 25 with nephrotic syndrome in remission and 25 normal children. The 24 h urine total protein and random urine protein-creatinine ratio were assessed on these samples. Linear regression analysis of the results showed excellent correlation between the values (r = 0.81, p less than 0.001). A random urine protein-creatinine ratio of greater than 3.5 correlated with massive proteinuria, while a ratio less than 0.2 was suggestive of physiological values. The sensitivity, specificity, positive and negative predictive values of the protein-creatinine ratio in massive proteinuria were very high. We conclude that the random urine protein-creatinine ratio can be used reliably to assess the degree of proteinuria in children. PMID:1752671

Iyer, R S; Shailaja, S N; Bhaskaranand, N; Baliga, M; Venkatesh, A

1991-05-01

305

Amylase:creatinine clearance ratios, serum amylase, and lipase after operations with cardiopulmonary bypass.  

PubMed

Forty-two adults who underwent cardiac operations were studied prospectively for evidence of clinical or subclinical pancreatitis. Clinically detectable pancreatitis was not seen. Serum amylase and lipase levels did not change significantly following operation. The amylase:creatinine clearance ratio (ACCR) immediately following operation was abnormally elevated in 31% of the samples obtained, and the mean ACCR increased from 2.08 +/- 1.85% before operation to 6.2% +/- 6.77% (P less than 0.05). An abnormally elevated ACCR was most often associated with a low urine creatinine concentration. The mean urine creatinine level decreased significantly from 78 +/- 53 mg/dl before operation to 38 +/- 49 mg/dl immediately following operation (P less than 0.02), and 73% of the samples obtained at that time had an abnormally low urine creatinine level (P less than 0.01). The abnormalities observed in ACCR and urine creatinine could not be related to any of several variables presumed to reflect the degree of perioperative physiologic stress, nor could they be related to postoperative hemodynamic performance. It was concluded that ACCR rises following cardiac operation because of perioperative changes in renal function, and not as a reflection of subclinical pancreatic injury. PMID:6193594

Smith, C R; Schwartz, S I

1983-09-01

306

Reduced creatinine clearance is associated with early development of subcutaneous tophi in people with gout  

PubMed Central

Background Although typically a late feature of gout, tophi may present early in the course of disease. The aim of this study was to identify factors associated with the presence of early tophaceous disease. Methods People with gout for <10 years were prospectively recruited, and had a comprehensive clinical assessment including examination for subcutaneous tophi. The clinical factors independently associated with the presence and number of tophi were analyzed using regression models. Results Of the 290 participants, there were 47 (16.2%) with clinically apparent tophi. In univariate analysis, those with tophi were older, were more frequently taking diuretics and colchicine prophylaxis, and had lower creatinine clearance. The association between the presence of tophi and creatinine clearance was strongest in those with creatinine clearance ?30 ml/min. In logistic regression analysis, creatinine clearance ?30 ml/min was associated with the presence of tophi, even after adjusting for ethnicity, corticosteroid use, colchicine use and diuretic use (multivariate adjusted odds ratio 7.0, p?=?0.005). Participants with tophi reported higher frequency of gout flares, pain scores, patient global assessment scores, and HAQ scores. Conclusions The presence of tophi is associated with more symptomatic disease in people with gout for <10 years. Creatinine clearance is independently associated with early presentation of subcutaneous tophi.

2013-01-01

307

Uric Acid and Dementia in Community-Dwelling Older Persons  

PubMed Central

Background The biological action of uric acid (UA) in humans is controversial. UA is considered an antioxidant compound, but preclinical evidence suggests a proinflammatory action. Epidemiological studies found that hyperuricemia is associated with conditions leading to dementia. Our aim is to investigate the relationship between UA levels and dementia in older persons. Methods Cross-sectional study performed in 1,016 community-dwelling older persons participating in the InCHIANTI study. Participants underwent determination of circulating UA levels and neuropsychological evaluation. A multivariate logistic regression model was used to estimate the probability of participants belonging to the highest and middle UA tertile to be affected by dementia compared to those in the lowest tertile. Results Demented persons had higher UA levels (p = 0.001) and the prevalence of persons affected by dementia increased across UA tertiles (p < 0.0001). Independent of several confounders, persons belonging to the highest UA tertile had a threefold (OR = 3.32; 95% CI: 1.06–10.42) higher probability to suffer from a dementia syndrome while those in the middle UA tertile tended to have a higher probability of being demented compared to those in the lowest tertile. Conclusion In a population-based sample, high circulating UA levels are associated with an increased likelihood to be affected by a dementia syndrome.

Ruggiero, Carmelinda; Cherubini, Antonio; Lauretani, Fulvio; Bandinelli, Stefania; Maggio, Marcello; Di Iorio, Angelo; Zuliani, Giovanni; Dragonas, Charalampos; Senin, Umberto; Ferrucci, Luigi

2009-01-01

308

Schlieren photography study of energy absorption by uric acid nuclei.  

PubMed

Previous studies using microfocus x-ray radiography on concentric laminated uric acid calculi following in vitro extracorporeal shock-wave lithotripsy (ESWL) has demonstrated the enlargement of the matrix layers. The Schlieren technique was used to verify the hypothesis that the incident energy would be concentrated in the matrix layers by total internal reflection. Because of the rough surface of the stone, the ultrasonic beam (4 MHz) was incident at various angles. At the critical Rayleigh angle (45.9 degrees +/- 0.5 degrees ), the reflected beam consisted of a spectacularly reflected lobe and a reradiated leaky Rayleigh wave. Different critical Lamb angles, theta(L), of 30.8 degrees, 38.1 degrees and 50.8 degrees (experimental uncertainty 0.5 degrees ) were also determined. Depending on the angle of incidence on the stone surface, a Rayleigh wave can be produced and/or one or more layers, as a whole, are set into vibration (Lamb excitation), with the result that shell-like fragments consisting of one or more layers, break off the stones at sites of weaker bonding, as has been noted in previous in vitro lithotripsy experiments by our group. PMID:10722923

Lafaut, J P; Leroy, O; Wevers, M; Devolder, S; Baert, L

2000-02-01

309

Serum uric Acid is associated with coronary artery calcification.  

PubMed

Uric acid (UA) is associated with atherosclerosis, and coronary artery calcium (CAC) is a marker of atherosclerosis. The authors studied the association between UA and CAC. A total of 663 asymptomatic patients (564 men; mean age, 55±7 years) were evaluated for the presence of CAC. The study population was divided into three tertiles according to their UA levels, and the prevalence of CAC was compared between the tertiles. CAC was detected in 349 (53%) patients. Levels of UA were significantly higher in those with CAC than in those without CAC (5.6+1.2 vs 5.3+1.3; P=.003). The odds ratio for the presence of CAC in the highest vs lowest UA tertile was 1.72 (95% confidence interval, 1.17-2.51). The highest UA tertile remained associated with the presence of CAC after adjustment for known cardiovascular risk factors. The results show that high serum UA levels are associated with the presence of CAC. PMID:24739097

Grossman, Chagai; Shemesh, Joseph; Koren-Morag, Nira; Bornstein, Gil; Ben-Zvi, Ilan; Grossman, Ehud

2014-06-01

310

Uric acid inhibition of dipeptidyl peptidase IV in vitro is dependent on the intracellular formation of triuret.  

PubMed

Uric acid affects endothelial and adipose cell function and has been linked to diseases such as hypertension, metabolic syndrome, and cardiovascular disease. Interestingly uric acid has been shown to increase endothelial progenitor cell (EPC) mobilization, a potential mechanism to repair endothelial injury. Since EPC mobilization is dependent on activity of the enzyme CD26/dipeptidyl peptidase (DPP)IV, we examined the effect uric acid will have on CD26/DPPIV activity. Uric acid inhibited the CD26/DPPIV associated with human umbilical vein endothelial cells but not human recombinant (hr) CD26/DPPIV. However, triuret, a product of uric acid and peroxynitrite, could inhibit cell associated and hrCD26/DPPIV. Increasing or decreasing intracellular peroxynitrite levels enhanced or decreased the ability of uric acid to inhibit cell associated CD26/DPPIV, respectively. Finally, protein modeling demonstrates how triuret can act as a small molecule inhibitor of CD26/DPPIV activity. This is the first time that uric acid or a uric acid reaction product has been shown to affect enzymatic activity and suggests a novel avenue of research in the role of uric acid in the development of clinically important diseases. PMID:24925478

Mohandas, Rajesh; Sautina, Laura; Beem, Elaine; Schuler, Anna; Chan, Wai-Yan; Domsic, John; McKenna, Robert; Johnson, Richard J; Segal, Mark S

2014-08-01

311

Differentiation of uric acid versus non-uric acid kidney stones in the presence of iodine using dual-energy CT  

NASA Astrophysics Data System (ADS)

In this study, the feasibility of differentiating uric acid from non-uric acid kidney stones in the presence of iodinated contrast material was evaluated using dual-energy CT (DECT). Iodine subtraction was accomplished with a commercial three material decomposition algorithm to create a virtual non-contrast (VNC) image set. VNC images were then used to segment stone regions from tissue background. The DE ratio of each stone was calculated using the CT images acquired at two different energies with DECT using the stone map generated from the VNC images. The performance of DE ratio-based stone differentiation was evaluated at five different iodine concentrations (21, 42, 63, 84 and 105 mg/ml). The DE ratio of stones in iodine solution was found larger than those obtained in non-iodine cases. This is mainly caused by the partial volume effect around the boundary between the stone and iodine solution. The overestimation of the DE ratio leads to substantial overlap between different stone types. To address the partial volume effect, an expectation-maximization (EM) approach was implemented to estimate the contribution of iodine and stone within each image pixel in their mixture area. The DE ratio of each stone was corrected to maximally remove the influence of iodine solutions. The separation of uric-acid and non-uric-acid stone was improved in the presence of iodine solution.

Wang, J.; Qu, M.; Leng, S.; McCollough, C. H.

2010-03-01

312

Wood plastic composite at different urea concentrations  

NASA Astrophysics Data System (ADS)

Wood plastic composite (WPC) has been prepared with a low grade wood simul ( Salmalia malabarica) of Bangladesh under Co-60 gamma irradiation using MMA as the bulk monomer combined with methanol as the swelling solvent at different urea concentrations. Effect of a second solute such as NVP, TPGDA and TMPTA in the impregnating solution is evaluated. NVP appears to be the best co-additive/second solute among all the additives used to yield the composite with the highest polymer loading (PL) and tensile strength (TS) at 0.5% urea concentration.

Husain, M. M.; Khan, Mubarak A.; Ali, K. M. Idriss; Hasan, A. J. M. Moynul

1995-04-01

313

1-(o-Tol-yl)thio-urea  

PubMed Central

In the title compound, C8H10N2S, the o-tolyl group and the thio­urea core are planar. The mean planes of the two groups are almost perpendicular [82.19?(8)°]. The thio­urea group is in the thio­amide form, in which resonance is present. In the crystal structure, mol­ecules are linked by inter­molecular N—H?S hydrogen bonds, forming two infinite chains parallel to the (110) and (10) planes.

Correa, Rodrigo S.; Ribeiro, Leandro; Ellena, Javier; Estevez-Hernandez, Osvaldo; Duque, Julio

2008-01-01

314

Vitamin C Intake and Serum Uric Acid Concentration in Men1  

PubMed Central

Objective We examined associations between vitamin C intake and serum uric acid in a population-based study. Methods We included 1,387 men without hypertension, and Body Mass Index <30 kg/m2 in the Health Professional Follow-up Study. Dietary intake was assessed with a semi-quantitative food frequency questionnaire validated for use in this population. Serum uric acid concentrations were measured. Results Greater intakes of total vitamin C were significantly associated with lower serum uric acid concentrations, after adjustment for smoking, BMI, ethnicity, blood pressure, presence of gout, use of aspirin, and intake of energy, alcohol, dairy protein, fructose, meat, seafood, and coffee. An inverse dose-response association was observed through vitamin C intake of 400–500 mg/d, and then reached a plateau. Adjusted mean uric acid concentrations across total vitamin C intake categories (<90, 90–249, 250–499, 500–999, or ? 1000 mg/d) were 6.4, 6.1, 6.0, 5.7, and 5.7 mg/dl, respectively (P for trend<0.001). Greater vitamin C intake was associated with lower prevalence of hyperuricemia (serum uric acid > 6 mg/dl). The multivariate ORs for hyperuricemia across total vitamin C intake categories were 1 (reference), 0.58, 0.57, 0.38, and 0.34 (95% CI: 0.20–0.58; P-trend< 0.001). When we used dietary data, which were assessed 4–8 years before blood collection, as predictors, we observed similar inverse associations between vitamin C intake and uric acid. Conclusions These population-based data indicate that vitamin C intake is inversely associated with serum uric acid concentrations. These findings support a potential role of vitamin C in the prevention of hyperuricemia and gout.

Gao, Xiang; Curhan, Gary; Forman, John P.; Ascherio, Alberto; Choi, Hyon K.

2009-01-01

315

Serum Uric Acid and Chronic Kidney Disease: The Role of Hypertension  

PubMed Central

Background There are inconsistent findings on the role of hyperuricemia as an independent risk factor for chronic kidney disease (CKD). Hypertension has been implicated as a factor influencing the association between serum uric acid and CKD. In this population-based study we investigated the association between serum uric acid and decline in renal function and tested whether hypertension moderates this association. Methods We included 2601 subjects aged 55 years and over from the Rotterdam Study. Serum uric acid and estimated glomerular filtration rate (eGFR) were assessed at baseline. After average 6.5 years of follow-up, second eGFR was assessed. CKD was defined as eGFR<60 ml/min/1.73 m2. All associations were corrected for socio-demographic and cardiovascular factors. Results Each unit (mg/dL) increase in serum uric acid was associated with 0.19 ml/min per 1.73 m2 faster annual decline in eGFR. While the association between serum uric acid and incidence of CKD was not significant in our study population (Hazard Ratio: 1.12, 95% confidence interval [CI]: 0.98–1.28), incorporating our results in a meta-analysis with eleven published studies revealed a significant association (Relative Risk: 1.18, 95%CI: 1.15–1.22). In the stratified analyses, we observed that the associations of serum uric acid with eGFR decline and incident CKD were stronger in hypertensive subjects (P for interaction?=?0.046 and 0.024, respectively). Conclusions Our findings suggest that hyperuricemia is independently associated with a decline in renal function. Stronger association in hypertensive individuals may indicate that hypertension mediates the association between serum uric acid and CKD.

Sedaghat, Sanaz; Hoorn, Ewout J.; van Rooij, Frank J. A.; Hofman, Albert; Franco, Oscar H.; Witteman, Jacqueline C. M.; Dehghan, Abbas

2013-01-01

316

Role of thin descending limb urea transport in renal urea handling and the urine concentrating mechanism  

PubMed Central

Urea transporters UT-A2 and UT-B are expressed in epithelia of thin descending limb of Henle's loop and in descending vasa recta, respectively. To study their role and possible interaction in the context of the urine concentration mechanism, a UT-A2 and UT-B double knockout (UT-A2/B knockout) mouse model was generated by targeted deletion of the UT-A2 promoter in embryonic stem cells with UT-B gene knockout. The UT-A2/B knockout mice lacked detectable UT-A2 and UT-B transcripts and proteins and showed normal survival and growth. Daily urine output was significantly higher in UT-A2/B knockout mice than that in wild-type mice and lower than that in UT-B knockout mice. Urine osmolality in UT-A2/B knockout mice was intermediate between that in UT-B knockout and wild-type mice. The changes in urine osmolality and flow rate, plasma and urine urea concentration, as well as non-urea solute concentration after an acute urea load or chronic changes in protein intake suggested that UT-A2 plays a role in the progressive accumulation of urea in the inner medulla. These results suggest that in wild-type mice UT-A2 facilitates urea absorption by urea efflux from the thin descending limb of short loops of Henle. Moreover, UT-A2 deletion in UT-B knockout mice partially remedies the urine concentrating defect caused by UT-B deletion, by reducing urea loss from the descending limbs to the peripheral circulation; instead, urea is returned to the inner medulla through the loops of Henle and the collecting ducts.

Lei, Tianluo; Zhou, Lei; Layton, Anita T.; Zhou, Hong; Zhao, Xuejian; Bankir, Lise

2011-01-01

317

An improved electrochemical creatinine detection method via a Jaffe-based procedure.  

PubMed

The detection of creatinine via an enzymeless electrochemical method is reported through an indirect electrochemical system in which the picrate anion consumed upon the reaction with creatinine is electrochemically measured. After careful optimisation it is found that in pH 13 two linear analytical ranges are possible utilising an Edge Plane Pyrolytic Graphite (EPPG) electrode: 0-6 mM and 7.5-11.5 mM, with a limit of detection (3?) corresponding to 0.27 mM; all measurements were taken after a five minute reaction time. Furthermore, screen printed carbon electrodes were applied to the same system and yielded remarkably similar linear ranges to the case of the EPPG electrode: 0-6 mM and 6-11 mM, with a limit of detection (3?) of 0.72 mM. These results are critically analysed and contrasted with the previous literature. This electrochemical protocol is applied to the detection of urinary creatinine where we find creatinine content of three samples falling well within our reported linear ranges and more importantly indicating correct kidney function. Additionally our electrochemical results are 'benchmarked' against UV/Vis spectrometry. The devised electroanalytical protocols have the potential to serve as a more solid foundation for electrochemical creatinine testing and have potential to be applied as a point-of-care diagnostics system through the use of screen printing technology, especially considering urinary creatinine concentrations fall within our reported linear ranges for both healthy adults and adults with deficient glomerular filtration. PMID:24051600

Randviir, Edward P; Kampouris, Dimitrios K; Banks, Craig E

2013-11-01

318

Effect of urea concentration on aggregation of amyloidogenic hexapeptides (NFGAIL).  

PubMed

We have performed large-scale all-atom molecular dynamics (MD) simulations to study the aggregation behavior of four NFGAIL hexapeptides in the aqueous urea solution, with a urea concentration ranging from 0 to 5 M. We find that urea in general suppresses the peptide aggregation, but suppression slows down in the intermediation concentration regime around 3 M. Two competing mechanisms of urea are determined: urea molecules accumulated near the first solvation shell (FSS) tend to unfold the hexapeptide, which favors aggregation; on the other hand, the tight hydrogen bonds formed between urea and peptide mainchains hinder the association of peptides which disfavors the formation of the ?-sheet. Furthermore, the different nonlinear urea concentration dependences of the urea-peptide and peptide-peptide hydrogen bonds lead to a nonmonotonic behavior, with a weak enhancement in the peptide aggregation around 3 M. PMID:24328094

Cai, Zhuowei; Li, Jingqiang; Yin, Chunji; Yang, Zaixing; Wu, Jianlan; Zhou, Ruhong

2014-01-01

319

On the relationship between glomerular filtration rate and serum creatinine in children  

Microsoft Academic Search

The Schwartz formula (eGFR?=?kL\\/Scr, with k?=?0.55) to determine the estimated glomerular filtration rate (eGFR) in children\\u000a with chronic kidney disease (CKD), based on length (L) and serum creatinine (Scr) has recently been updated for enzymatic\\u000a serum creatinine concentrations, resulting in k?=?0.413. Based on a meta-analysis, we evaluated the validity of this updated\\u000a equation and other published equations for healthy children.

Hans Pottel; Felix M. Mottaghy; Zahur Zaman; Frank Martens

2010-01-01

320

Liposomal Doxorubicin in Suspected Ovarian Carcinoma Patient With Very Low Creatinine Clearance Test Value  

PubMed Central

A 74-year-old woman presented with moderate ascites with diagnostic features of adenocarcinoma of the ovary. She was given 1 course of cisplatin- and paclitaxel-based chemotherapy but did not have her creatinine clearance tested, which was consequently found to be very low. She subsequently presented with gross debilitating symptoms and toxicity. However, she tolerated 20 mg/m2 dose of liposomal doxorubicin every 4 weeks and was a good responder. Only 1 previous study of use of doxorubicin was found in such a low level of creatinine clearance.

Bose, Chinmoy K.; Bose, Banani; Basu, Amit; Basu, Srabani

2008-01-01

321

Degradability of creatinine under sewer conditions affects its potential to be used as biomarker in sewage epidemiology.  

PubMed

Creatinine was proposed to be used as a population normalising factor in sewage epidemiology but its stability in the sewer system has not been assessed. This study thus aimed to evaluate the fate of creatinine under different sewer conditions using laboratory sewer reactors. The results showed that while creatinine was stable in wastewater only, it degraded quickly in reactors with the presence of sewer biofilms. The degradation followed first order kinetics with significantly higher rate in rising main condition than in gravity sewer condition. Additionally, daily loads of creatinine were determined in wastewater samples collected on Census day from 10 wastewater treatment plants around Australia. The measured loads of creatinine from those samples were much lower than expected and did not correlate with the populations across the sampled treatment plants. The results suggested that creatinine may not be a suitable biomarker for population normalisation purpose in sewage epidemiology, especially in sewer catchment with high percentage of rising mains. PMID:24631876

Thai, Phong K; O'Brien, Jake; Jiang, Guangming; Gernjak, Wolfgang; Yuan, Zhiguo; Eaglesham, Geoff; Mueller, Jochen F

2014-05-15

322

Aldehyde-containing urea-absorbing polysaccharides  

NASA Technical Reports Server (NTRS)

A novel aldehyde containing polymer (ACP) is prepared by reaction of a polysaccharide with periodate to introduce aldehyde groups onto the C2 - C3 carbon atoms. By introduction of ether and ester groups onto the pendant primary hydroxyl solubility characteristics are modified. The ACP is utilized to absorb nitrogen bases such as urea in vitro or in vivo.

Mueller, W. A.; Hsu, G. C.; Marsh, H. E., Jr. (inventors)

1977-01-01

323

Wood plastic composite at different urea concentrations  

Microsoft Academic Search

Wood plastic composite (WPC) has been prepared with a low grade wood simul (Salmalia malabarica) of Bangladesh under Co-60 gamma irradiation using MMA as the bulk monomer combined with methanol as the swelling solvent at different urea concentrations. Effect of a second solute such as NVP, TPGDA and TMPTA in the impregnating solution is evaluated. NVP appears to be the

M. M. Husain; Mubarak A. Khan; K. M. Idriss Ali; A. J. M. Moynul Hasan

1995-01-01

324

EDTA assisted synthesis of hydroxyapatite nanoparticles for electrochemical sensing of uric acid.  

PubMed

Hydroxyapatite nanoparticles have been synthesized using EDTA as organic modifier by a simple microwave irradiation method and its application for the selective determination of uric acid (UA) has been demonstrated. Electrochemical behavior of uric acid at HA nanoparticle modified glassy carbon electrode (E-HA/GCE) has been investigated by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), linear sweep voltammetry (LSV) and amperometry. The E-HA modified electrode exhibits efficient electrochemical activity towards uric acid sensing without requiring enzyme or electron mediator. Amperometry studies revealed that the fabricated electrode has excellent sensitivity for uric acid with the lowest detection limit of 142nM over a wide concentration range from 1×10(-7) to 3×10(-5)M. Moreover, the studied E-HA modified GC electrode exhibits a good reproducibility and long-term stability and an admirable selectivity towards the determination of UA even in the presence of potential interferents. The analytical performance of this sensor was evaluated for the detection of uric acid in human urine and blood serum samples. PMID:25063159

Kanchana, P; Sekar, C

2014-09-01

325

Covalent immobilization of uricase inside a plastic vial for uric acid determination in serum and urine.  

PubMed

Uricase from Candida species was immobilized covalently onto the inner wall of a plasticized polyvinyl chloride (PVC/plastic) vial through glutraldehyde coupling with a 65.23% retention of its initial activity and a conjugation yield of 0.37 mg/cm(2). The vial-bound enzyme showed the optimum activity at pH 7.2, when incubated at 45°C for 5 min. There was a linear relationship between the immobilized uricase activity and the uric acid concentration in the range of 0.01 to 1.2 mM with an apparent Km for uric acid of 0.17 mM. The vial-bound enzyme was employed for an enzymic colorimetric determination of uric acid in serum and urine. The minimum detection limit of the method was 0.01 mM. The analytical recoveries of added uric acid in serum (10 and 20 mM) were 98.0 and 96.5%, respectively. Within and between assays, the coefficients of variation (CVs) for urate in sera determinations were 5.6 and 4.7%, respectively. A good correlation (r = 0.997) was obtained between the serum uric acid values by the standard enzymic colorimetric method using free enzyme and the present method. The vial was reused 200-times over a period of 4 months, when stored at 4°C. PMID:24717661

Chauhan, Nidhi; Preeti; Pinky; Pundir, C S

2014-01-01

326

Gold nanoparticles - enhanced capillary electrophoresis- chemiluminescence assay of trace uric acid  

PubMed Central

A sensitive method based on gold nanoparticle-enhanced capillary electrophoresis-chemiluminescence detection was developed for quantifying uric acid in serum. In this work, gold nanoparticles were added into the running buffer of capillary electrophoresis to catalyze the post-column chemiluminescence reaction between luminol and hydrogen peroxide, achieving highly efficient chemiluminescence emission. Negative peaks were produced due to the inhibitory effects on chemiluminescence emission from uric acid eluted from the electrophoretic capillary. The decrease in chemiluminescence intensity was proportional to the concentration of uric acid in the range of 2.5 × 10?7 ~ 1.0 × 10?5 M. Detection limit was 4.6 × 10?8 M uric acid. Ten human serum samples were analyzed by the presented method. Serum level of uric acid was found to be in the range from 204 to 324 ?M for healthy subjects (n=5), and from 464 to 497 ?M for diabetic patients (n=5). The two groups were significantly different (p < 0.05). The results suggested a potential application of the proposed assay in rapid primary diagnosis of diseases such as diabetes.

Zhao, Shulin; Lan, Xuehua; Liu, Yi-Ming

2009-01-01

327

Uric Acid Stimulates Fructokinase and Accelerates Fructose Metabolism in the Development of Fatty Liver  

PubMed Central

Excessive dietary fructose intake may have an important role in the current epidemics of fatty liver, obesity and diabetes as its intake parallels the development of these syndromes and because it can induce features of metabolic syndrome. The effects of fructose to induce fatty liver, hypertriglyceridemia and insulin resistance, however, vary dramatically among individuals. The first step in fructose metabolism is mediated by fructokinase (KHK), which phosphorylates fructose to fructose-1-phosphate; intracellular uric acid is also generated as a consequence of the transient ATP depletion that occurs during this reaction. Here we show in human hepatocytes that uric acid up-regulates KHK expression thus leading to the amplification of the lipogenic effects of fructose. Inhibition of uric acid production markedly blocked fructose-induced triglyceride accumulation in hepatocytes in vitro and in vivo. The mechanism whereby uric acid stimulates KHK expression involves the activation of the transcription factor ChREBP, which, in turn, results in the transcriptional activation of KHK by binding to a specific sequence within its promoter. Since subjects sensitive to fructose often develop phenotypes associated with hyperuricemia, uric acid may be an underlying factor in sensitizing hepatocytes to fructose metabolism during the development of fatty liver.

Lanaspa, Miguel A.; Sanchez-Lozada, Laura G.; Cicerchi, Christina; Li, Nanxing; Roncal-Jimenez, Carlos A.; Ishimoto, Takuji; Le, Myphuong; Garcia, Gabriela E.; Thomas, Jeffrey B.; Rivard, Christopher J.; Andres-Hernando, Ana; Hunter, Brandi; Schreiner, George; Rodriguez-Iturbe, Bernardo; Sautin, Yuri Y.; Johnson, Richard J.

2012-01-01

328

Synergetic effects of nanoporous support and urea on enzyme activity.  

PubMed

We report synergetic effects of functionalized mesoporous silica (FMS) and urea to promote favorable protein conformational changes. The specific activity of glucose isomerase (GI) entrapped in FMS in the presence of urea was approximately double that of GI in solution in the absence of urea. Rather than losing all activity in a denaturing solution of 8.0 M urea, the specific activity of GI entrapped in FMS remained higher than the highest specific activity of GI free in solution. PMID:17341123

Lei, Chenghong; Shin, Yongsoon; Liu, Jun; Ackerman, Eric J

2007-04-01

329

Is uric acid an indicator of metabolic syndrome in the first-degree relatives of patients with type 2 diabetes?  

PubMed Central

Background: To determine whether uric acid levels are associated with the components of metabolic syndrome and whether uric acid is a significant factor for development of metabolic syndrome in the first-degree relatives of type 2 diabetic patients as high risk group. Materials and Methods: A total of 694 (182 male and 512 female, aged 30-69 years) first-degree relatives of type 2 diabetic patients during 2007-2011 were enrolled. The height, weight, waist circumference, blood pressure, fasting plasma glucose, lipid profile and uric acid concentrations were measured. Metabolic syndrome was defined by NCEP-ATP III. Results: Uric acid was associated with waist circumference, blood pressure, triglyceride and HDL-cholesterol level in both sexes (r = 0.1-0.3, P < 0.05). The prevalence of metabolic syndrome in the fourth quartile of uric acid (64.4% of male and 60.2% of female population) was significantly more than those in the first (25.5% of male and 31.2% of female population) and second quartiles (33.3% of male and 32.0% of female population). The mean of uric acid in people with metabolic syndrome was significantly higher than in those without (6.6 ± 1.2 mg/dL vs. 5.8 ± 1.2 mg/dL; P = 0.0001). The age-adjusted odds ratios (95% confidence interval) of uric acid for metabolic syndrome in univariate analysis were [1.60 (1.23-2.07); P = 0.008] for men and [1.61 (1.34-1.92); P = 0.0001] for women but the effect of uric acid in multivariate logistic regression was not significant. Conclusions: Uric acid is associated with majority of the metabolic syndrome components. People with metabolic syndrome have higher uric acid levels. However, uric acid probably is not an independent factor to predict the metabolic syndrome.

Salehidoost, Rezvan; Aminorroaya, Ashraf; Zare, Maryam; Amini, Massoud

2012-01-01

330

Association of plasma uric acid with ischaemic heart disease and blood pressure: mendelian randomisation analysis of two large cohorts  

PubMed Central

Objectives To assess the associations between both uric acid levels and hyperuricaemia, with ischaemic heart disease and blood pressure, and to explore the potentially confounding role of body mass index. Design Mendelian randomisation analysis, using variation at specific genes (SLC2A9 (rs7442295) as an instrument for uric acid; and FTO (rs9939609), MC4R (rs17782313), and TMEM18 (rs6548238) for body mass index). Setting Two large, prospective cohort studies in Denmark. Participants We measured levels of uric acid and related covariables in 58?072 participants from the Copenhagen General Population Study and 10?602 from the Copenhagen City Heart Study, comprising 4890 and 2282 cases of ischaemic heart disease, respectively. Main outcome Blood pressure and prospectively assessed ischaemic heart disease. Results Estimates confirmed known observational associations between plasma uric acid and hyperuricaemia with risk of ischaemic heart disease and diastolic and systolic blood pressure. However, when using genotypic instruments for uric acid and hyperuricaemia, we saw no evidence for causal associations between uric acid, ischaemic heart disease, and blood pressure. We used genetic instruments to investigate body mass index as a potentially confounding factor in observational associations, and saw a causal effect on uric acid levels. Every four unit increase of body mass index saw a rise in uric acid of 0.03 mmol/L (95% confidence interval 0.02 to 0.04), and an increase in risk of hyperuricaemia of 7.5% (3.9% to 11.1%). Conclusion By contrast with observational findings, there is no strong evidence for causal associations between uric acid and ischaemic heart disease or blood pressure. However, evidence supports a causal effect between body mass index and uric acid level and hyperuricaemia. This finding strongly suggests body mass index as a confounder in observational associations, and suggests a role for elevated body mass index or obesity in the development of uric acid related conditions.

2013-01-01

331

[The features of uric acid metabolism in women in climacterium].  

PubMed

The purpose of the study was to establish the prevalence of uric acid (UA) metabolism disturbances as a possible risk factor of urate nephropathy in women of various age groups. The authors carried out a retrospective analysis of 757 case histories and performed uricemia and uricosuria screening in women aged 18 to 69 years. The study revealed significant age-dependent elevation of uricemia, with hyperuricemia (HUE) at the age of 60 to 69 years old. The study also found age-dependent increase of HUE rate with its significant elevation in postmenopausal women (older than 50 years), compared with HUE rate in reproductive age women (18 to 49 years old) -37.9% vs. 11.4%. For the first time the researchers established UA excretion level and found a significant tendency of uricosuria to decrease with age (p < 0.016 between the groups of 40 to 49 and 50 to 59 years old). The highest rate of hyperuricosuria was revealed in women of 40 to 49 years old (22.2%), while in women of 18 to 29 and 60 to 69 years old it was 10.1% to 12.1%. For the first time the authors established the rate of hypouricosuria in women, which culminated in women older than 50 (22% of cases). The increase of HUE rate, which is most prominent in postmenopausal women, is associated with the decrease in UA excretion, accompanied by the decrease of hyperuricosuria rate and increase of hypouricosuria rate. Taking into account high prevalence of UA metabolism disturbances in women older than 50, menopause may be considered a risk factor of HUE and urate nephropathy. PMID:15984582

Solov'eva, O A; Balkarov, I M; Smetnik, V P; Eliseeva, N A; Lebedeva, M V; Shovskaia, T N; Aleksandrovskaia, T N

2005-01-01

332

Molecular recognition: A simple dinaphthyridine receptor for urea  

Microsoft Academic Search

A new dinaphthyridine receptor 1 is designed that efficiently binds to urea probably by six hydrogen bonds forming a chloroform soluble 1:1 complex and selectively extracts urea into chloroform from its mixture with thiourea. The receptor 1 has fifteen fold higher binding constant for urea than the truncated receptor 2 possibly due to formation of greater number of hydrogen bonds

Shyamaprosad Goswami; Rakhi Mukherjee

1997-01-01

333

Tracer Studies of Urea Kinetics in Growing Pigs: I. The Effect of Intravenous Infusion of Urea on Urea Recycling and the Site of Urea Secretion into the Gastrointestinal Tract  

Microsoft Academic Search

Four gilts (average BW 80 kg) were used in the first experiment to study the effect of i.v. infusion of urea on urea kinetics by means of a radioisotope dilution technique. The pigs were fed twice daily 600 g of a cornstarch-based diet formulated to contain 16% CP by supplementation with isolated soy protein. Infusion of urea, com- pared with

W. C. Sauers R. Mosenthinz; C. F. M. de Lange

2010-01-01

334

75 FR 74746 - Solid Urea From Russia and Ukraine  

Federal Register 2010, 2011, 2012, 2013

...731-TA-340-E and 340-H (Third Review)] Solid Urea From Russia and Ukraine AGENCY: United...concerning the antidumping duty orders on solid urea from Russia and Ukraine...of the antidumping duty orders on solid urea from Russia and Ukraine would be...

2010-12-01

335

76 FR 15339 - Solid Urea From Russia and Ukraine  

Federal Register 2010, 2011, 2012, 2013

...731-TA-340-E and 340-H (Third Review)] Solid Urea From Russia and Ukraine AGENCY: United...concerning the antidumping duty orders on solid urea from Russia and Ukraine...of the antidumping duty orders on solid urea from Russia and Ukraine would be...

2011-03-21

336

76 FR 77015 - Solid Urea From Russia and Ukraine  

Federal Register 2010, 2011, 2012, 2013

...340-E and 340-H (Third Review)] Solid Urea From Russia and Ukraine Determination On...of the antidumping duty orders on solid urea from Russia and Ukraine would be likely...4279 (December 2011), entitled Solid Urea from Russia and Ukraine:...

2011-12-09

337

Synergetic Effects of Nanoporous Support and Urea on Enzyme Activity  

SciTech Connect

Here we report that synergetic effects of functionalized nanoporous support and urea on enzyme activity enhancement. Even in 8.0 M urea, the specific activity of GI entrapped in FMS was still higher than the highest specific activity of GI free in solution, indicating the strong tolerance of GI in FMS to the high concentration of urea.

Lei, Chenghong; Shin, Yongsoon; Liu, Jun; Ackerman, Eric J.

2007-02-01

338

21 CFR 176.320 - Sodium nitrate-urea complex.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Sodium nitrate-urea complex. 176.320 Section 176.320 Food...and Paperboard § 176.320 Sodium nitrate-urea complex. Sodium nitrate-urea complex may be safely used as a component...

2013-04-01

339

Incorporation of nitrification inhibitors with urea and urea-ammonium nitrate for irrigated corn  

Microsoft Academic Search

Nitrapyrin [2-chloro-6-(trichloromethyl)pyridine] has been shown to delay nitrification and may increase nitrogen (N) utilization efficiency of crops under N loss conditions. Current application recommendations suggest immediate incorporation. With fertilizer N sources such as urea and urea-ammonium nitrate (UAN) solution, immediate incorporation may not be practical. Experiments were conducted with irrigated corn (Zea mays L.) over 3 years to determine if

G. L. Malzer

1988-01-01

340

Winter Wheat and Maize Response to Urea Ammonium Nitrate and a New Urea Formaldehyde Polymer Fertilizer  

Microsoft Academic Search

Slow release N fertilizers have potential to improve yield and nitrogen use efficiency (NUE) in winter wheat (Triticum aestivum L.) and maize (Zea mays L.). A slow release urea formaldehyde polymer (UFP) was compared with aqueous urea ammonium nitrate (UAN) ((NH2)2CO, NH4NO3) during a 2-yr field experiment in North Carolina. Crops were grown on Candor (sandy, siliceous, thermic Grossarenic Kandiudults),

Sheri Cahill; Deanna Osmond; Carl Crozier; Daniel Israel; Randy Weisz

2007-01-01

341

Choice of urea-spray models in CFD simulations of urea-SCR systems  

Microsoft Academic Search

The sensitivity of modeling choices to obtained results for Eulerian–Lagrangian CFD simulations of urea-SCR systems has been investigated for a system consisting of an AdBlue-spray located at the exhaust pipe wall, directed into the exhaust gas flow. The decomposition of urea is modeled as being heat transfer limited and taking place at a constant temperature (425K). It is shown that

Henrik Ström; Andreas Lundström; Bengt Andersson

2009-01-01

342

Serum Cystatin C as a Marker of Renal Function in Critically Ill Patients With Normal Serum Creatinine  

PubMed Central

Background: Serum creatinine as a classic marker of renal function has several limitations in the detection of renal dysfunction. Objectives: This study assessed the validity of serum cystatin C as a marker of renal function in critically ill patients with normal serum creatinine. Patients and Methods: Eighty adult patients referred to intensive care units with serum creatinine levels < 1.5 mg/dL and without hemodynamic instability were chosen and their serum creatinine and cystatin C levels were measured. A 24-hour urine sample was collected to calculate creatinine clearance (Ccr). Renal dysfunction was defined as Ccr < 80 mL/min/1.73 m2. Results: There were significant correlations between measured Ccr and 1/serum creatinine (R = 0.51, P < 0.001) and 1/serum cystatin C (R = 0.25, P = 0.028). The difference between false negative rates of serum creatinine (93.33%) and cystatin C (80%) in the detection of renal dysfunction was significant (P = 0.032). Receiver operating characteristic curve analysis illustrated that area under the curve of serum creatinine and cystatin C for detecting renal dysfunction were 0.711 and 0.607, respectively; however, this difference was not significant (P = 0.222). Conclusions: Our data demonstrated that serum cystatin C is not superior to serum creatinine in the early detection of renal dysfunction in critically ill patients.

Sagheb, Mohammad Mahdi; Namazi, Soha; Geramizadeh, Bita; Karimzadeh, Amin; Oghazian, Mohammad Bagher; Karimzadeh, Iman

2014-01-01

343

Comparison between the enzymatic vitros assay for creatinine determination and three other methods adapted on the Olympus analyzer.  

PubMed

To evaluate the relationship between the enzymatic Vitros assay for creatinine determination and other methods, we determined creatinine concentration in 400 heparin samples. Plasma creatinine level was successively determined on the Vitros 750 analyzer (Johnson & Johnson Co., Rochester, NY) and on the Olympus AU2700 analyzer (Olympus France, Rungis, France), using three reagents in the same assay: Olympus-Jaffé and two enzymatic commercial kits-Crea Plus (Roche Diagnostics, Meylan, France) and Enzymatic Creatinine (Randox, Mauguio, France). Comparison of Jaffé and enzymatic measurements of plasma creatinine levels revealed a high correlation when considering all values ranged from 20-1000 micromol/l (r > 0.99). However, for values <60 micromol/l, enzymatic reagents provided best results. Enzymatic methodology is a better clinical choice for the accurate measurement of creatinine, especially for neonates, pediatrics, and hematology units. Because analytical performance and the costs of Randox creatinine were satisfactory for our laboratory, this method, adapted on the Olympus analyzer, was chosen for routine determination of creatinine levels. According to the Valtec protocol (8), no interferences such as hemolysis, lipemia, or bilirubin were detected for Enzymatic Creatinine Randox. PMID:14614747

Badiou, S; Dupuy, A M; Descomps, B; Cristolead, J P

2003-01-01

344

Protecting group free synthesis of urea-linked glycoconjugates: efficient synthesis of ?-urea glycosides in aqueous solution.  

PubMed

A method for the protecting group free synthesis of ?-urea-linked glycoconjugates has been developed. The one step process, involving reactions between urea and d-glucose, N-acetyl-d-glucosamine or d-xylose in acidic aqueous solution, furnishes the corresponding ?-urea glycosides in modest yields. This simple and efficient procedure is applicable to the synthesis of ?-urea tethered amino acid-carbohydrate conjugates. PMID:24796538

Ichikawa, Yoshiyasu; Minami, Takahiro; Kusaba, Shohei; Saeki, Nobuyoshi; Tonegawa, Yuta; Tomita, Yumiko; Nakano, Keiji; Kotsuki, Hiyoshizo; Masuda, Toshiya

2014-05-21

345

Uric acid protects membranes and linolenic acid from ozone-induced oxidation  

SciTech Connect

Aqueous preparations of linolenic acid, bovine serum albumin, and bovine erythrocyte membrane fragments were bubbled with ozone in the presence or absence of uric acid. Ozonation of the membrane fragments or the bovine serum albumin did not result in protein degradation. After 15 min of ozonation, the absorbance of the thiobarbituric acid-reactive material increased by 0.34 in the linolenic acid preparation and by 0.08 in the suspension of membrane fragments. In the presence of uric acid, these changes in absorbance were reduced to 0.14 for the fatty acid and to 0.01 for the membrane fragments. This result indicates that uric acid protects lipids from ozone-induced oxidation.

Meadows, J.; Smith, R.C.; Reeves, J.

1986-05-29

346

Electronic structures and spectra of two antioxidants: uric acid and ascorbic acid  

NASA Astrophysics Data System (ADS)

Electronic absorption and fluorescence spectra of aqueous solutions of two well known antioxidants, uric acid and ascorbic acid (vitamin C), have been studied at different pH. The observed spectra have been interpreted in terms of neutral and anionic forms of the molecules with the help of molecular orbital calculations. The N 3 site of uric acid has been shown to be the most acidic. Fluorescence of uric acid seems to originate from an anion of the molecule in a wide pH range. Around pH 3, both the neutral and anionic forms of ascorbic acid appear to be present in aqueous solutions. In aqueous media, ascorbic acid appears to get converted easily to its dehydro form and this conversion does not seem to be reversible. An anion of dehydroascorbic acid seems to be formed on heating dehydroascorbic acid in aqueous solutions.

Shukla, M. K.; Mishra, P. C.

1996-04-01

347

Uric acid provides an antioxidant defense in humans against oxidant- and radical-caused aging and cancer: a hypothesis  

Microsoft Academic Search

During primate evolution, a major factor in lengthening life-span and decreasing age-specific cancer rates may have been improved protective mechanisms against oxygen radicals. We propose that one of these protective systems is plasma uric acid, the level of which increased markedly during primate evolution as a consequence of a series of mutations. Uric acid is a powerful antioxidant and is

B. N. Ames; R. Cathcart; E. Schwiers; P. Hochstein

1981-01-01

348

Uric acid has a J-shaped association with cardiovascular and all-cause mortality in kidney transplant recipients.  

PubMed

The association between serum uric acid and kidney graft and recipient survival is uncertain. During 2000-2011, we measured serum uric acid at week 10 after transplantation. Of 2748 transplanted patients, 2200 (80.1%) attended this visit. After a median follow-up of 7.4 yr, 378 patients had died, 143 from a cardiovascular cause, and 185 patients lost their graft. The third quintile of uric acid levels (357-405 ?M) had the lowest mortality risk and was used as reference group. In Cox proportional hazard models adjusting for graft and patient characteristics, the fifth quintile of uric acid levels (>474 ?M) was independently associated with cardiovascular mortality (hazard ratio [HR] = 2.87 [1.55-5.32], p = 0.001) and all-cause mortality (HR = 1.57 [1.09-2.25], p = 0.02). Also, the lowest quintile of uric acid levels (<309 ?M) showed a trend toward increased risk of cardiovascular mortality (HR = 1.79 [0.90-3.58], p = 0.10) and all-cause mortality (HR = 1.31 [0.89-1.93], p = 0.18). The increased risk at low uric acid levels was confined to diabetic recipients. Uric acid was not associated with death-censored graft loss. In conclusion, uric acid has a J-shaped association with cardiovascular and all-cause mortality in kidney transplant recipients. PMID:24372653

Dahle, Dag Olav; Jenssen, Trond; Holdaas, Hallvard; Leivestad, Torbjørn; Vårdal, Mari; Mjøen, Geir; Reisaeter, Anna V; Toft, Ingrid; Hartmann, Anders

2014-01-01

349

Uric acid reduces brain damage and improves the benefits of rt-PA in a rat model of thromboembolic stroke  

Microsoft Academic Search

Uric acid is a natural antioxidant that protects the brain in a model of transient focal ischemia in rats. Here we sought to investigate whether uric acid was protective in a model of thromboembolic brain ischemia in rats, and whether the global benefit of recombinant tissue plasminogen activator (rt-PA) was improved by the combined treatment. Adult male Sprague–Dawley rats underwent

Eduardo Romanos; Anna M Planas; Sergio Amaro; Ángel Chamorro

2007-01-01

350

Association of three genetic loci with uric acid concentration and risk of gout: a genome-wide association study  

Microsoft Academic Search

Background: Hyperuricaemia, a highly heritable trait, is a key risk factor for gout. We aimed to identify novel genes associated with serum uric acid concentration and gout. Methods: Genome-wide association studies were done for serum uric acid in 7699 participants in the Framingham cohort and in 4148 participants in the Rotterdam cohort. Genome-wide significant single nucleotide polymorphisms (SNPs) were replicated

Abbas Dehghan; Anna Köttgen; Qiong Yang; Shih-Jen Hwang; WH Linda Kao; Fernando Rivadeneira; Eric Boerwinkle; Daniel Levy; Albert Hofman; Brad C Astor; Emelia J Benjamin; Cornelia M van Duijn; Jacqueline C Witteman; Josef Coresh; Caroline S Fox

2008-01-01

351

Comparative semiempirical and ab initio study of the structural and chemical properties of uric acid and its anions  

NASA Astrophysics Data System (ADS)

Semiempirical, density functional theory (DFT), and ab initio calculations have been performed to assess the relative stabilities of 15 possible tautomer forms of neutral uric acid, and of the different urate mono- and dianion forms. These methods have also been used to compute ionization potentials (IPs) for uric acid and its derived anions. Overall, we have found that semiempirical calculations, in particular PM3, perform well as compared with B3LYP or MP2 computations toward these different structural and chemical properties of uric acid: the triketo form of uric acid is the most stable tautomer form of neutral uric acid. Three other tautomer forms are relatively close in energy, within the range 2-6 kcal/mol above the triketo form, with a mean energy deviation of only 1.3 kcal/mol between PM3 and DFT or ab initio results; the monoanion form of uric acid obtained by abstracting one proton in position 3 (denoted UAN3-) is the most stable form among all four possible urate monoanions both in gas phase and in solution; the dianion form of uric acid obtained by abstracting two protons, respectively, in positions 3 and 9 of uric acid (denoted UAN3-N9-) is the most stable urate dianion form both in gas phase and in solution. However, these two most stable species do not have the lowest IPs in solution: among monoanions and dianions, respectively, the species with the lowest IPs are UAN7- and UAN7-N9-.

Altarsha, Muhannad; Monard, Gérald; Castro, Bertrand

352

PHYSICAL ACTIVITY ALTERS URINARY ALBUMIN\\/ CREATININE RATIO IN TYPE 1 DIABETIC PATIENT  

Microsoft Academic Search

While the best way to identify microalbuminuria is to determine albumin excretion rate (AER) in a 24 h urine sample. Published data have shown that calculation of an albumin\\/creatinine ratio (ACR) in a spot urine sample has reasonable rate of sensitivity and specificity. We aimed to evaluate the effect of daily exercise on ACR and estimate the best time for

Ercan Tuncel; Erdinc Erturk; Canan Ersoy; Sinem Kiyici; Cevdet Duran; Nesrin Kuru; Sazi Imamoglu

2004-01-01

353

Urinary catecholamine and metadrenaline to creatinine ratios in dogs with a phaeochromocytoma  

Microsoft Academic Search

Urinary adrenaline (epinephrine), noradrenaline, dopamine, metadrenaline (metanephrine) and normetadrenaline to creatinine ratios were measured from spot samples of seven client-owned dogs with a histologically confirmed phaeochromocytoma. Urine was collected on day 0 in the hospital in six dogs, and additionally on days 2, 6 and 7 after discharge in two of these dogs. In one dog, urine was sampled on

P. H. Kook; P. Grest; S. Quante; F. S. Boretti; C. E. Reusch

2010-01-01

354

Urinary corticoid : creatinine ratios in dogs with pituitary-dependent hypercortisolism during trilostane treatment  

Microsoft Academic Search

Background: The adrenocorticotropic hormone (ACTH) stimulation test is used to evaluate trilostane treatment in dogs with hypercortisolism. Hypothesis: The urinary corticoid : creatinine ratio (UCCR) is a good alternative to the ACTH stimulation test to determine optimal trilostane dose. Animals: Eighteen dogs with pituitary-dependent hypercortisolism. Methods: In this prospective study, the dose of trilostane was judged to be optimal on

S. Galac; J. J. C. W. M. Buijtels; H. S. Kooistra

2009-01-01

355

Renal failure in a patient with postpolio syndrome and a normal creatinine level.  

PubMed

Patients with renal failure who are taking trimethoprim have an increased risk of developing hyperkalemia, which can cause muscle weakness. In patients with postpolio syndrome, a normal creatinine level could be abnormally high, renal failure is possible because of lack of creatinine production, and the muscle weakness from resultant hyperkalemia could be more severe because of their underlying condition. This abnormally high creatinine level has been termed from this point relative renal failure. The objective of the study was to review a case in which relative renal failure and hyperkalemia caused muscle weakness that manifested as shortness of breath and confusion with electrocardiographic changes. A dehydrated patient with relative renal failure and postpolio syndrome had taken trimethoprim-sulfamethoxazole that caused symptomatic hyperkalemia. The patient presented with muscle weakness, shortness of breath, and confusion, with her postpolio syndrome compounding the situation and likely making the muscle weakness more severe. A patient on trimethoprim with renal failure is at an increased risk of developing hyperkalemia. Patients with postpolio syndrome could have severe muscle weakness from the hyperkalemia and could have renal failure even with a normal creatinine level. This case report will remind treating physicians to evaluate such patients for hyperkalemia if they present with muscle weakness, especially if the patient has renal failure and is on trimethoprim. PMID:20950983

Leming, Melissa K; Breyer, Michael J

2012-01-01

356

In severe acute kidney injury, a higher serum creatinine is paradoxically associated with better patient survival  

Microsoft Academic Search

Lack of precise, reliable and consistent measures of kidney dysfunction in acute kidney injury (AKI) causes uncertainty in the definition and management of this important condition and interferes with treat- ment standardization. Serum creatinine (SCr) remains a key determinant in the management of renal dysfunction. In disparate populations, previous authors suggested a paradoxical association between higher SCr and better survival.

Jorge Cerda ´; Magdalena Cerda ´; Patricia Kilcullen; Jayne Prendergast

2007-01-01

357

INTERPRETATION OF URINE RESULTS USED TO ASSESS CHEMICAL EXPOSURE WITH EMPHASIS ON CREATININE ADJUSTMENTS: A REVIEW  

Microsoft Academic Search

This paper reviews the process of elimination of creatinine (CRE), and the limitations presented when using it to express urine concentrations. This literature review leads to three conclusions: (1) CRE excretion is subject to wide fluctuations due to specific internal and external factors; (2) the use of CRE to correct chemical concentrations in urine will not necessarily improve the correlation

Mark Frederick Boeniger; Larry K. Lowry; Jon Rosenberg

1993-01-01

358

Tailored reference limits for urine corticoid:creatinine ratio in dogs to answer distinct clinical questions  

Microsoft Academic Search

To establish reference intervals for the urinary corticoid:creatinine ratio (UCCR) determined by chemiluminometric immunoassay, UCCR was measured by this method in 50 healthy dogs. To assess the diagnostic performance of different cut-off levels, the UCCR of 66 dogs with hyperadrenocorticism and 87 dogs with diseases mimicking hyperadrenocorticism were used to construct a receiver operating characteristic (ROC) curve. The upper reference

F. Zeugswetter; N. Bydzovsky; D. Kampner; I. Schwendenwein

2010-01-01

359

Minimal Changes of Serum Creatinine Predict Prognosis in Patients after Cardiothoracic Surgery: A Prospective Cohort Study  

Microsoft Academic Search

Acute renal failure increases risk of death after car- diac surgery. However, it is not known whether more subtle changes in renal function might have an impact on outcome. Thus, the association between small serum creatinine changes after surgery and mortality, independent of other established perioperative risk indicators, was analyzed. In a prospective cohort study in 4118 patients who underwent

ANDREA LASSNIGG; DANIEL SCHMIDLIN; MOHAMED MOUHIEDDINE; LUCAS M. BACHMANN; WILFRED DRUML; PETER BAUER; MICHAEL HIESMAYR

2004-01-01

360

HOME AIR NICOTINE LEVELS AND URINE COTININE-CREATININE RATIOS IN PRESCHOOL CHILDREN  

EPA Science Inventory

We studied urine cotinine excretion in 27 children who attended a research day care center to determine the extent of correlation between urine cotinine-creatinine ratios (CCR) and intensity of nicotine exposure in the home. verage nicotine levels in home air were determined by a...

361

"Bite-and-Switch" approach using computationally designed molecularly imprinted polymers for sensing of creatinine.  

PubMed

A method for the selective detection of creatinine is reported, which is based on the reaction between polymerised hemithioacetal, formed by allyl mercaptan, o-phthalic aldehyde, and primary amine leading to the formation of fluorescent isoindole complex. This method has been demonstrated previously for the detection of creatine using creatine-imprinted molecularly imprinted polymers (MIPs) Since MIPs created using traditional methods were unable to differentiate between creatine and creatinine, a new approach to the rational design of a molecularly imprinted polymer (MIP) selective for creatinine was developed using computer simulation. A virtual library of functional monomers was assigned and screened against the target molecule, creatinine, using molecular modelling software. The monomers giving the highest binding score were further tested using simulated annealing in order to mimic the complexation of the functional monomers with template in the monomer mixture. The result of this simulation gave an optimised MIP composition. The computationally designed polymer demonstrated superior selectivity in comparison to the polymer prepared using traditional approach, a detection limit of 25 microM and good stability. The "Bite-and-Switch" approach combined with molecular imprinting can be used for the design of assays and sensors, selective for amino containing substances. PMID:11679238

Subrahmanyam, S; Piletsky, S A; Piletska, E V; Chen, B; Karim, K; Turner, A P

2001-12-01

362

Normalization of urinary biomarkers to creatinine during changes in glomerular filtration rate  

PubMed Central

Urinary biomarkers, such as albumin and other markers of kidney injury, are frequently reported as a normalized ratio to urinary creatinine (UCr) concentration [UCr] to control for variations in urine flow rate. The implicit assumption is that UCr excretion is constant across and within individuals, such that changes in the ratio will reflect changes in biomarker excretion. Using computer simulations of creatinine kinetics, we found that normalized levels of a biomarker reflecting tubular injury can be influenced by dynamic changes in the UCr excretion rate when the glomerular filtration rate changes. Actual timed urine collections from hospitalized patients with changing glomerular filtration rates and/or critical illness exhibited variability in UCr excretion rates across and within individuals. Normalization by [UCr] may, therefore, result in an underestimation or overestimation of the biomarker excretion rate depending on the clinical context. Lower creatinine excretion in the setting of acute kidney injury or poor renal allograft function may amplify a tubular injury biomarker signal, thereby increasing its clinical utility. The variability of creatinine excretion, however, will complicate the determination of a threshold value for normalized biomarkers of acute or chronic kidney disease, including albumin. Thus, we suggest that the most accurate method to quantify biomarkers requires the collection of timed urine specimens to estimate the actual excretion rate, provided that the biomarker is stable over the period of collection. This ideal must be balanced, however, against practical considerations.

Waikar, Sushrut S.; Sabbisetti, Venkata S.; Bonventre, Joseph V.

2011-01-01

363

Urinary Creatinine Excretion as an Index of the Fat-Free Mass Composition in Rats.  

National Technical Information Service (NTIS)

The relationship between urinary creatinine excretion and fat-free mass was studied in 70 male (39 to 247 days old) and 20 female (45 to 108 days old) albino rats. Fat-free mass, water, muscle protein, non-muscle protein and mineral were highly correlated...

K. S. K. Chinn

1967-01-01

364

Association Between Serum Soluble CD30 and Serum Creatinine Before and After Renal Transplantation  

Microsoft Academic Search

ObjectiveThere is increasing evidence that circulating levels of soluble CD30 (sCD30) may represent a biomarker for outcome in kidney transplantation. The aim of this study was to measure the pre- and posttransplantation serum levels of sCD30 in cadaveric kidney transplant recipients and correlate them with serum creatinine.

M. López-Hoyos; D. San Segundo; M. J. Benito; G. Fernández-Fresnedo; J. C. Ruiz; E. Rodrigo; C. Gómez-Alamillo; A. Benito; M. Arias

2008-01-01

365

Normalization of urinary biomarkers to creatinine during changes in glomerular filtration rate.  

PubMed

Urinary biomarkers, such as albumin and other markers of kidney injury, are frequently reported as a normalized ratio to urinary creatinine (UCr) concentration [UCr] to control for variations in urine flow rate. The implicit assumption is that UCr excretion is constant across and within individuals, such that changes in the ratio will reflect changes in biomarker excretion. Using computer simulations of creatinine kinetics, we found that normalized levels of a biomarker reflecting tubular injury can be influenced by dynamic changes in the UCr excretion rate when the glomerular filtration rate changes. Actual timed urine collections from hospitalized patients with changing glomerular filtration rates and/or critical illness exhibited variability in UCr excretion rates across and within individuals. Normalization by [UCr] may, therefore, result in an underestimation or overestimation of the biomarker excretion rate depending on the clinical context. Lower creatinine excretion in the setting of acute kidney injury or poor renal allograft function may amplify a tubular injury biomarker signal, thereby increasing its clinical utility. The variability of creatinine excretion, however, will complicate the determination of a threshold value for normalized biomarkers of acute or chronic kidney disease, including albumin. Thus, we suggest that the most accurate method to quantify biomarkers requires the collection of timed urine specimens to estimate the actual excretion rate, provided that the biomarker is stable over the period of collection. This ideal must be balanced, however, against practical considerations. PMID:20555318

Waikar, Sushrut S; Sabbisetti, Venkata S; Bonventre, Joseph V

2010-09-01

366

FIELD AND LABORATORY STUDIES COMPARING NUTRISPHERE-NITROGEN UREA WITH UREA IN NORTH DAKOTA, ARKANSAS, AND MISSISSIPPI  

Microsoft Academic Search

Nitrification and ammonia volatility are two important impediments to nitrogen (N) use efficiency and crop uptake around the world. Nutrisphere® is a relatively new product whose manufacturer claims both nitrification and urea volatilization inhibiting properties. Urea coated with Nutrisphere is and the resulting fertilizer is called Nutrisphere®-N urea, or Nutrisphere-N (NSN). Eight field studies on spring (Triticum aestivum L.) or

David Franzen; R. Jay Goos; Richard J. Norman; Timothy W. Walker; Trenton L. Roberts; Nathan A. Slaton; Gregory Endres; Roger Ashley; James Staricka; John Lukach

2011-01-01

367

Uric Acid Levels and All-Cause and Cardiovascular Mortality in the Hemodialysis Population  

PubMed Central

Summary Background and objectives Hyperuricemia is associated with hypertension, coronary artery disease, and chronic kidney disease. However, there are no specific data on the relationship of uric acid to cardiovascular disease in the chronic hemodialysis setting. Design, setting, participants, & measurements Data from 5827 patients on chronic hemodialysis from six countries affiliated with the Dialysis Outcomes and Practice Patterns Study (DOPPS) were analyzed. All laboratory data were based upon the initial cross-section of patients in DOPPS I and II. Cox regression was used to calculate the hazard ratio (HR) of all-cause and cardiovascular (CV) mortality with adjustments for case-mix including 14 classes of comorbidity. Results There were no clinically significant differences in baseline characteristics between those who had measured uric acid (n = 4637) and those who did not (n = 1190). Uric acid level was associated with lower all-cause mortality (HR: 0.95, 95% confidence interval [CI]: 0.90 to 1.00 per 1 mg/dl higher uric acid level) and CV mortality (HR: 0.92, 95% CI: 0.86 to 0.99). When analyzed as a dichotomous variable, the adjusted HR at uric acid ?8.2 mg/dl compared with >8.2 mg/dl was 1.24 (95% CI: 1.03 to 1.49) for all-cause mortality and 1.54 (95% CI: 1.15 to 2.07) for CV mortality. Conclusions Higher uric acid levels were associated with lower risk of all-cause and CV mortality in the hemodialysis population. These results are in contrast to the association of hyperuricemia with higher cardiovascular risk in the general population and should be the subject of further research.

Latif, Walead; Karaboyas, Angelo; Tong, Lin; Winchester, James F.; Arrington, Charlotte J.; Pisoni, Ronald L.; Marshall, Mark R.; Kleophas, Werner; Levin, Nathan W.; Sen, Ananda; Robinson, Bruce M.

2011-01-01

368

Computed phase diagrams for the system: Sodium hydroxide-uric acid-hydrochloric acid-water  

NASA Astrophysics Data System (ADS)

Renal stone formation is made complex by the variety of solid phases that are formed, by the number of components in the aqueous phase, and by the multiplicity of ionic dissociation and association processes that are involved. In the present work we apply phase diagrams calculated by the use of equilibrium constants from the ternary system sodium hydroxide-uric acid-water to simplify and make more rigorous the understanding of the factors governing dissolution and precipitation of uric acid (anhydrous and dihydrate) and sodium urate monohydrate. The system is then examined in terms of four components. Finally, procedures are described for fluids containing more than four components. The isotherms, singular points, and fields of supersaturation and undersaturation are shown in various forms of phase diagrams. This system has two notable features: (1) in the coordinates -log[H 2U] versus -log[NaOH], the solubility isotherms for anhydrous uric acid and uric acid dihydrate approximate straight lines with slopes equal to +1 over a wide range of concentrations. As a result, substantial quantities of sodium acid urate monohydrate can precipitate from solution or dissolve without changing the degree of saturation of uric acid significantly. (2) The solubility isotherm for NaHU·H 2O has a deltoid shape with the low-pH branch having a slope of infinity. As a result of the vertical slope of this isotherm, substantial quantities of uric acid can dissolve or precipitate without changing the degree of saturation of sodium acid urate monohydrate significantly. The H 2U-NaOH singular point has a pH of 6.87 at 310 K in the ternary system.

Brown, W. E.; Gregory, T. M.; Füredi-Milhofer, H.

1987-07-01

369

Serum Uric Acid Is Not an Independent Risk Factor for Premature Coronary Artery Disease  

PubMed Central

Background/Aim There is still debate on the role of serum uric acid as an independent risk factor for coronary artery disease (CAD), particularly premature CAD. This study aimed to investigate whether serum uric acid is a risk factor for premature CAD and whether it can influence the severity of coronary artery stenosis. Methods Candidates for coronary artery angiography (age <45 years for men and <55 years for women) who met the inclusion criteria were enrolled in this study. Clinical data of the patients as well as their serum uric acid levels were compared with the presence of premature CAD. Results In total, 473 patients were included and divided into two groups: the premature CAD group consisted of 245 patients (age = 46.2 ± 5.7 years; males = 110, 44.9%) and the normal coronary group consisted of 228 subjects (age = 45.7 ± 6.4 years; males = 62, 27.2%). Uric acid was significantly related to the presence of CAD, but this relationship was not significant after adjustment for confounding variables, including classic CAD risk factors. CAD patients were then categorized based on the extent of the disease (from minimal CAD to three-vessel disease); however, unlike the classic risk factors of CAD, uric acid was not significantly different between these groups (p = 0.10), and a similar result was observed after adjustment for confounders. Conclusion Uric acid is not an independent risk factor for premature CAD but is weakly correlated with the extent of the disease; nevertheless, this relationship requires further investigation.

Zand, Sara; Shafiee, Akbar; Boroumand, Mohammadali; Jalali, Arash; Nozari, Younes

2013-01-01

370

Benfotiamine attenuates nicotine and uric acid-induced vascular endothelial dysfunction in the rat.  

PubMed

The study has been designed to investigate the effect of benfotiamine, a thiamine derivative, in nicotine and uric acid-induced vascular endothelial dysfunction (VED) in rats. Nicotine (2 mg kg(-1)day(-1), i.p., 4 weeks) and uric acid (150 mg kg(-1)day(-1), i.p., 3 weeks) were administered to produce VED in rats. The development of VED was assessed by employing isolated aortic ring preparation and estimating serum and aortic concentration of nitrite/nitrate. Further, the integrity of vascular endothelium was assessed using the scanning electron microscopy (SEM) of thoracic aorta. Moreover, the oxidative stress was assessed by estimating serum thiobarbituric acid reactive substances (TBARS) and aortic superoxide anion generation. The administration of nicotine and uric acid produced VED by impairing the integrity of vascular endothelium and subsequently decreasing serum and aortic concentration of nitrite/nitrate and attenuating acetylcholine-induced endothelium dependent relaxation. Further, nicotine and uric acid produced oxidative stress, which was assessed in terms of increase in serum TBARS and aortic superoxide generation. However, treatment with benfotiamine (70 mg kg(-1)day(-1), p.o.) or atorvastatin (30 mg kg(-1)day(-1) p.o., a standard agent) markedly prevented nicotine and uric acid-induced VED and oxidative stress by improving the integrity of vascular endothelium, increasing the concentration of serum and aortic nitrite/nitrate, enhancing the acetylcholine-induced endothelium dependent relaxation and decreasing serum TBARS and aortic superoxide anion generation. Thus, it may be concluded that benfotiamine reduces the oxidative stress and consequently improves the integrity of vascular endothelium and enhances the generation of nitric oxide to prevent nicotine and uric acid-induced experimental VED. PMID:18951979

Balakumar, Pitchai; Sharma, Ramica; Singh, Manjeet

2008-01-01

371

Predictive Value of 8 Genetic Loci for Serum Uric Acid Concentration  

PubMed Central

Aim To investigate the value of genomic information in prediction of individual serum uric acid concentrations. Methods Three population samples were investigated: from isolated Adriatic island communities of Vis (n?=?980) and Kor?ula (n?=?944), and from general population of the city of Split (n?=?507). Serum uric acid concentration was correlated with the genetic risk score based on 8 previously described genes: PDZK1, GCKR, SLC2A9, ABCG2, LRRC16A, SLC17A3, SLC16A9, and SLC22A12, represented by a total of 16 single-nucleotide polymorphisms (SNP). The data were analyzed using classification and regression tree (CART) and general linear modeling. Results The most important variables for uric acid prediction with CART were genetic risk score in men and age in women. The percent of variance for any single SNP in predicting serum uric acid concentration varied from 0.0%-2.0%. The use of genetic risk score explained 0.1%-2.5% of uric acid variance in men and 3.9%-4.9% in women. The highest percent of variance was obtained when age, sex, and genetic risk score were used as predictors, with a total of 30.9% of variance in pooled analysis. Conclusion Despite overall low percent of explained variance, uric acid seems to be among the most predictive human quantitative traits based on the currently available SNP information. The use of genetic risk scores is a valuable approach in genetic epidemiology and increases the predictability of human quantitative traits based on genomic information compared with single SNP approach.

Gunjaca, Grgo; Boban, Mladen; Pehlic, Marina; Zemunik, Tatijana; Budimir, Danijela; Kolcic, Ivana; Lauc, Gordan; Rudan, Igor; Polasek, Ozren

2010-01-01

372

Uric acid-induced arrestment as a possible bird host cue (kairomone) in nymphs and adults of the lone star tick, Amblyomma americanum (L.)  

Microsoft Academic Search

Nymphs and adults of the lone star tick, Amblyomma americanum (L.), respond to uric acid by arrestment, but not attraction. When placed on uric acid treated surfaces, ~ 60% of 100 ticks engaged in rigorous search behavior ceased ambulatory activity, became akinetic and curled their legs, and grouped in small clusters. This response has biological significance because uric acid is

Jay A. Yoder; Jeff L. Domingus; Gregory C. Luerman

2003-01-01

373

Preliminary Use of Uric Acid as a Biomarker for Wading Birds on Everglades Tree Islands, Florida, United States  

USGS Publications Warehouse

Concentrations of organic biomarkers and concentrations of phosphorus in soil cores can potentially be used as proxies for historic population densities of wading birds on tree islands in the Florida Everglades. This report focuses on establishing a link between the organic biomarker uric acid found in wading bird guano and the high phosphorus concentrations in tree island soils in the Florida Everglades. Uric acid was determined in soil core sections, in surface samples, and in bird guano by using a method of high-performance liquid chromatography-mass spectrometry (HPLC-MS) developed for this purpose. Preliminary results show an overall correlation between uric acid and total phosphorus in three soil cores, with a general trend of decreasing concentrations of both uric acid and phosphorus with depth. However, we have also found no uric acid in a soil core having high concentrations of phosphorus. We believe that this result may be explained by different geochemical circumstances at that site.

Bates, Anne.L.; Orem, William H.; Newman, Susan; Gawlik, Dale E.; Lerch, Harry E.; Corum, Margo D.; Van Winkle, Monica

2010-01-01

374

An amperomertic uric acid biosensor based on immobilization of uricase onto polyaniline-multiwalled carbon nanotube composite film.  

PubMed

A highly sensitive, amperometric uric acid biosensor possessing unique physical, electro-conductive properties of carbon nanotubes is described for determination of uric acid level in serum. A uric acid biosensor was constructed after immobilization of uricase onto a polyaniline/CNT matrix by carbonamide linkage. The scanning electron micrographs confirmed the immobilization of globular enzyme onto the electroploymerized polyaniline/CNT composite. Employment of carbon nanotubes composite in the present electrode leads to a very quick response time of 8 sec with the minimum detection limit of 5 microM along with an increase in shelf-life of electrode system to >180 days with slight loss of enzyme activity. Efficiency of the present amperometric uric acid biosensor was validated by quantitative estimation of uric acid level in biological serum of healthy individuals and the persons suffering from hyperuricemia and gout. PMID:20367113

Bhambi, Manu; Sumana, G; Malhotra, B D; Pundir, C S

2010-08-01

375

Performance of Creatinine and Cystatin C GFR Estimating Equations in an HIV-positive population on Antiretrovirals  

PubMed Central

Objective To evaluate the performance of CKD-EPI creatinine, cystatin C and creatinine-cystatin C estimating equations in HIV-positive patients. Methods We evaluated the performance of the MDRD Study and CKD-EPI creatinine 2009, CKD-EPI cystatin C 2012 and CKD-EPI creatinine-cystatin C 2012 glomerular filtration rate (GFR) estimating equations compared to GFR measured using plasma clearance of iohexol in 200 HIV-positive patients on stable antiretroviral therapy. Creatinine and cystatin C assays were standardized to certified reference materials. Results Of the 200 participants, median (IQR) CD4 count was 536 (421) and 61% had an undetectable HIV-viral load. Mean (SD) measured GFR (mGFR) was 87 (26) ml/min/1.73m2. All CKD-EPI equations performed better than the MDRD Study equation. All three CKD-EPI equations had similar bias and precision. The cystatin C equation was not more accurate than the creatinine equation. The creatinine-cystatin C equation was significantly more accurate than the cystatin C equation and there was a trend toward greater accuracy than the creatinine equation. Accuracy was equal or better in most subgroups with the combined equation compared to either alone. Conclusions The CKD-EPI cystatin C equation does not appear to be more accurate than the CKD-EPI creatinine equation in patients who are HIV-positive, supporting the use of the CKD-EPI creatinine equation for routine clinical care for use in North American populations with HIV. The use of both filtration markers together as a confirmatory test for decreased estimated GFR based on creatinine in individuals who are HIV-positive requires further study.

INKER, Lesley A; WYATT, Christina; CREAMER, Rebecca; HELLINGER, James; HOTTA, Matthew; LEPPO, Maia; LEVEY, Andrew S; OKPARAVERO, Aghogho; GRAHAM, Hiba; SAVAGE, Karen; SCHMID, Christopher H; TIGHIOUART, Hocine; WALLACH, Fran; KRISHNASAMI, Zipporah

2013-01-01

376

Phase transition and epitaxies between hydrated orthorhombic and anhydrous monoclinic uric acid crystals  

NASA Astrophysics Data System (ADS)

Anhydrous monoclinic and hydrated orthorhombic uric acid crystals can be nucleated and grown from pure water solutions either separately or together with epitaxial relationships. When crystals of one modification exist in the solution they can act as nucleation substrate for the crystals of the other modification. In both cases the new phase grows epitaxially on the substrate; the mutual orientations are the same but the contact planes are different. In addition, the anhydrous modification grows into the hydrated one which undergoes a phase transition by a dissolution-recrystallization process. It is likely that the same processes occur in human stones made up of uric acids.

Boistelle, R.; Rinaudo, C.

1981-05-01

377

Inactivation of Maize Phosphoenolpyruvate Carboxylase by Urea 1  

PubMed Central

Phosphoenolpyruvate carboxylase purified from leaves of maize (Zea mays, L.) is sensitive to the presence of urea. Exposure to 2.5 m urea for 30 min completely inactivates the enzyme, whereas for a concentration of 1.5 m urea, about 1 h is required. Malate appears to have no effect on inactivation by urea of phosphoenolpyruvate carboxylase. However, the presence of 20 mm phosphoenolpyruvate or 20 mm glucose-6-phosphate prevents significant inactivation by 1.5 m urea for at least 1 h. The inactivation by urea is reversible by dilution. The inhibition by urea and the protective effects of phosphoenolpyruvate and glucose-6-phosphate are associated with changes in aggregation state.

Wedding, Randolph T.; Dole, Paul; Chardot, Thierry P.; Wu, Min-Xian

1992-01-01

378

Uric acid is associated with the prevalence but not disease progression of multiple system atrophy in Chinese population.  

PubMed

Oxidative stress is involved in the pathogenesis of multiple system atrophy (MSA). Uric acid has an antioxidative effect. Our aim is to clarify the correlations between serum uric acid and MSA in Chinese population. A total of 234 patients with probable MSA and 240 age- and gender- matched healthy controls were included in the study. The serum uric acid levels of all the patients and controls were evaluated. The Unified MSA Rating Scale (UMSARS) was used to assess the severity and the mean rate of annualized changes of UMSARS to assess the progression of MSA. The mean age of MSA patients was 58.90 ± 9.00 years and the mean disease duration was 2.60 ± 1.75 years. The serum uric acid levels of MSA patients were significantly lower than that of controls in males (p = 0.0001). The occurrence of MSA was increased in the lowest uric acid quartiles compared with the highest uric acid quartiles (p = 0.005). In a gender-specific analysis, increased occurrence was found in the lowest quartiles and second quartiles compared with the highest quartiles in males (p = 0.001 and p = 0.0001 respectively), but not in females. No correlation was found between the mean rate of annualized changes and serum levels of uric acid, as well as other independent factors, such as age, BMI, gender, subtype (C-type or P-type) and disease duration at the initial visit in 107 followed-up patients. MSA patients have lower levels of serum uric acid than controls. High levels of serum uric acid may be associated with a lower prevalence of MSA in the Chinese population, especially in males. However, serum uric acid does not deteriorate or ameliorate the progression of MSA. PMID:23801150

Cao, Bei; Guo, Xiaoyan; Chen, Ke; Song, Wei; Huang, Rui; Wei, Qian-Qian; Zhao, Bi; Shang, Hui-Fang

2013-10-01

379

Association between Vitamin D Insufficiency and Elevated Serum Uric Acid among Middle-Aged and Elderly Chinese Han Women  

PubMed Central

Background Association between vitamin D insufficiency and hyperuricemia has not been reported so far. We aimed to study the association of vitamin D insufficiency with elevated serum uric acid among middle-aged and elderly Chinese Han women. Methods We collected data from participants residing in Jinchang district of Suzhou from January to May, 2010. Serum uric acid, 25-hydroxy vitamin D and other traditional biomarkers including fasting plasma glucose and blood lipids were determined in 1726 women aged above 30 years. Association between vitamin D insufficiency and elevated uric acid was analyzed in premenopausal and postmenopausal women, respectively. Results Among postmenopausal women, 25-hydroxy vitamin D level of participants with elevated uric acid was lower than that of those with normal uric acid (median [interquartile range]: 35[28–57] vs 40[32–58], µg/L; P?=?0.006). Elevated uric acid was more prevalent in participants with vitamin D insufficiency compared to those without vitamin D insufficiency (16.50% vs 8.08%; P<0.001). Association between vitamin D insufficiency and elevated uric acid was not significant among premenopausal women. However, participants with vitamin D insufficiency were more likely to have elevated uric acid compared with those without vitamin D insufficiency among postmenopausal women (OR, 95% CI: 2.38, 1.47–3.87). Moreover, after excluding individuals with diabetes and/or hypertension, the association of vitamin D insufficiency with elevated uric acid was still significant (OR, 95% CI: 2.48, 1.17–5.44). Conclusions Vitamin D insufficiency was significantly associated with elevated uric acid among postmenopausal Chinese Han women. This study suggested that a clinical trial should be conducted to confirm the association of vitamin D insufficiency with hyperuricemia.

Li, Chao; Chao, Xiangqin; Zhang, Qiu; Zhang, Yonghong

2013-01-01

380

Creatinine - urine  

MedlinePLUS

... include: Antibiotics, such as cefoxitin or trimethoprim Cimetidine Cisplatin Do not stop taking any medicine before talking ... GS, Brendler CB. Evaluation of the urologic patient: history, physical examination, and urinalysis. In: Wein AJ, Kavoussi ...

381

1-Furfuryl-3-furoylthio-urea  

PubMed Central

The title compound, C11H10N2O3S, was synthesized from furoyl isothio­cyanate and furfurylamine in dry acetone. The thio­urea group is in the thio­amide form. The trans–cis geometry of the thio­urea group is stabilized by intra­molecular hydrogen bonding between the carbonyl and cis-thio­amide and results in a pseudo-S(6) planar ring which makes dihedral angles of 2.5?(3) and 88.1?(2)° with the furoyl and furfuryl groups, respectively. There is also an intra­molecular hydrogen bond between the furan O atom and the other thio­amide H atom. In the crystal structure, mol­ecules are linked by two inter­molecular N—H?O hydrogen bonds, forming dimers. These dimers are stacked within the crystal structure along the [010] direction.

Estevez-Hernandez, O.; Duque, J.; Ellena, J.; Correa, Rodrigo S.

2008-01-01

382

Blood biochemical factors in humans resistant and susceptible to formation of venous gas emboli during decompression  

Microsoft Academic Search

Summary  Blood biochemical parameters were measured in 12 male human subjects before and after exposure to a staged decompression protocol, with simulated extravehicular activity, during 3 days. Following the exposure, significant changes occurred in several parameters, including increases in blood urea nitrogen, inorganic phosphate, potassium, and osmolality, and decreases in uric acid and creatinine. Pre-exposure blood samples from subjects who were

James R. Jauchem; James M. Waligora; Johnny Conkin; David J. Horrigan; Philip C. Johnson

1986-01-01

383

Ammonium and urea removal by Spirulina platensis  

Microsoft Academic Search

Different concentrations either of ammonium chloride or urea were used in batch and fed-batch cultivations of Spirulina platensis to evaluate the possibility of substituting nitrate by cheaper reduced nitrogen sources in wastewaters biotreatment. The\\u000a maximum nitrogen concentration able to sustain the batch growth of this microalga without inhibition was 1.7 mM in both cases.\\u000a Ammonium chloride was limiting for the growth

A. Converti; S. Scapazzoni; A. Lodi; J. C. M. Carvalho

2006-01-01

384

Thienopyridine urea inhibitors of KDR kinase  

Microsoft Academic Search

A series of substituted thienopyridine ureas was prepared and evaluated for enzymatic and cellular inhibition of KDR kinase activity. Several of these analogs, such as 2, are potent inhibitors of KDR (<10nM) in both enzymatic and cellular assays. Further characterization of inhibitor 2 indicated that this analog possessed excellent in vivo potency (ED50 2.1mg\\/kg) as measured in an estradiol-induced mouse

H. Robin Heyman; Robin R. Frey; Peter F. Bousquet; George A. Cunha; Maria D. Moskey; Asma A. Ahmed; Niru B. Soni; Patrick A. Marcotte; Lori J. Pease; Keith B. Glaser; Melinda Yates; Jennifer J. Bouska; Daniel H. Albert; Candace L. Black-Schaefer; Peter J. Dandliker; Kent D. Stewart; Paul Rafferty; Steven K. Davidsen; Michael R. Michaelides; Michael L. Curtin

2007-01-01

385

Calibration and random variation of the serum creatinine assay as critical elements of using equations to estimate glomerular filtration rate  

Microsoft Academic Search

Equations using serum creatinine level, age, sex, and other patient characteristics often are used to estimate glomerular filtration rate (GFR) in both clinical practice and research studies. However, the critical dependence of these equations on serum creatinine assay calibration often is overlooked, and the reproducibility of estimated GFR is rarely discussed. We address these issues in frozen samples from 212

Josef Coresh; Brad C. Astor; Geraldine McQuillan; John Kusek; Tom Greene; Frederick Van Lente; Andrew S. Levey

2002-01-01

386

The relationships of proteinuria, serum creatinine, glomerular filtration rate with cardiovascular disease mortality in Japanese general population  

Microsoft Academic Search

Proteinuria, high serum creatinine, and reduced glomerular filtration rate (GFR) have been associated with increased mortality from cardiovascular disease (CVD) and all causes. However, the combined effect of proteinuria with serum creatinine and GFR on CVD or all-cause mortality has not been well investigated. We conducted a 10-year prospective cohort study of 30 764 men and 60 668 women aged

F Irie; H Iso; T Sairenchi; N Fukasawa; K Yamagishi; S Ikehara; M Kanashiki; Y Saito; H Ota; T Nose

2006-01-01

387

Expressing the Modification of Diet in Renal Disease Study Equation for Estimating Glomerular Filtration Rate with Standardized Serum Creatinine Values  

Microsoft Academic Search

Purpose: We sought to reexpress the 4-variable Modifi- cation of Diet in Renal Disease (MDRD) Study equation for estimation of glomerular filtration rate (GFR) using serum creatinine (Scr) standardized to reference methods. Methods: Serum specimens included creatinine refer- ence materials prepared by the College of American Pathologists (CAP), traceable to primary reference ma- terial at the NIST, with assigned values

Andrew S. Levey; Josef Coresh; Tom Greene; Jane Marsh; Lesley A. Stevens

388

Paired measurement of urinary creatinine in neonates based on a Jaffe and an enzymatic IDMS-traceable assay  

PubMed Central

Background Urinary creatinine can be quantified by Jaffe or enzymatic assays and is commonly used as denominator of urinary excretion of electrolytes or protein. Paired analysis in pediatric and adult samples documented inter-assay differences (up to 80%). We verified the interchangeability of two IDMS-traceable assays (Jaffe and enzymatic) for neonatal urine and report on neonatal urinary creatinine values using these IDMS-traceable methods. Methods Creatinine was measured in 84 neonatal urine samples from 46 neonates by an IDMS traceable Jaffe and enzymatic assay (Roche Diagnostics, Cobas c702 module). Creatinine values, differences in urinary creatinine and clinical characteristics were described and covariates of between assay difference were explored (Wilcoxon, Bland-Altman, correlation, multiple regression). Results Median Jaffe and enzymatic urinary creatinine concentrations were 9.25 (range 3.7-42.2) and 9.15 (range 3.8-42.9) mg/dL respectively, resulting in a median difference of 0.08 (SD 0.6, range ?2.4 to 0.96) mg/dL. In a multiple regression model, urinary enzymatic creatinine concentration (r?=?0.45) and postnatal age (r?=??0.59) remained independent variables of the difference between both assays (r2 adj?=?0.45). Conclusions The tested IDMS-traceable assays showed interchangeable in heterogeneous neonatal urine samples. Using these assays, neonatal urinary creatinine showed 5–20 fold lower values than those observed in children or adults with a significant negative correlation with postnatal age.

2014-01-01

389

Serum uric acid in relation to endogenous reproductive hormones during the menstrual cycle: findings from the BioCycle study  

PubMed Central

STUDY QUESTION Do uric acid levels across the menstrual cycle show associations with endogenous estradiol (E2) and reproductive hormone concentrations in regularly menstruating women? SUMMARY ANSWER Mean uric acid concentrations were highest during the follicular phase, and were inversely associated with E2 and progesterone, and positively associated with FSH. WHAT IS KNOWN ALREADY E2 may decrease serum levels of uric acid in post-menopausal women; however, the interplay between endogenous reproductive hormones and uric acid levels among regularly menstruating women has not been elucidated. STUDY DESIGN, SIZE, DURATION The BioCycle study was a prospective cohort study conducted at the University at Buffalo research centre from 2005 to 2007, which followed healthy women for one (n = 9) or 2 (n = 250) menstrual cycle(s). PARTICIPANTS/MATERIALS, SETTING, METHODS Participants were healthy women aged 18–44 years. Hormones and uric acid were measured in serum eight times each cycle for up to two cycles. Marginal structural models with inverse probability of exposure weights were used to evaluate the associations between endogenous hormones and uric acid concentrations. MAIN RESULTS AND THE ROLE OF CHANCE Uric acid levels were observed to vary across the menstrual cycle, with the lowest levels observed during the luteal phase. Every log-unit increase in E2 was associated with a decrease in uric acid of 1.1% (? = ?0.011; 95% confidence interval (CI): ?0.019, ?0.004; persistent-effects model), and for every log-unit increase in progesterone, uric acid decreased by ?0.8% (? = ?0.008; 95% CI: ?0.012, ?0.004; persistent-effects model). FSH was positively associated with uric acid concentrations, such that each log-unit increase was associated with a 1.6% increase in uric acid (? = 0.016; 95% CI: 0.005, 0.026; persistent-effects model). Progesterone and FSH were also associated with uric acid levels in acute-effects models. Of 509 cycles, 42 were anovulatory (8.3%). Higher uric acid levels were associated with increased odds of anovulation (odds ratio 2.39, 95% CI: 1.25, 4.56). LIMITATIONS, REASONS FOR CAUTION The change in uric acid levels among this cohort of healthy women was modest, and analysis was limited to two menstrual cycles. The women in this study were healthy and regularly menstruating, and as such there were few women with high uric acid levels and anovulatory cycles. WIDER IMPLICATIONS OF THE FINDINGS These findings demonstrate the importance of taking menstrual cycle phase into account when measuring uric acid in premenopausal women, and confirm the hypothesized beneficial lowering effects of endogenous E2 on uric acid levels. These findings suggest that there could be an underlying association affecting both sporadic anovulation and high uric acid levels among young, regularly menstruating women. Further studies are needed to confirm these findings and elucidate the connection between uric acid and reproductive and later cardiovascular health. STUDY FUNDING/COMPETING INTEREST(S) This work was supported by the Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health (contract # HHSN275200403394C). No competing interests declared.

Mumford, Sunni L.; Dasharathy, Sonya S.; Pollack, Anna Z.; Perkins, Neil J.; Mattison, Donald R.; Cole, Stephen R.; Wactawski-Wende, Jean; Schisterman, Enrique F.

2013-01-01

390

Dichloridobis(thio-urea-?S)nickel(II)  

PubMed Central

The title complex, [NiCl2(CH4N2S)2], has been synthesized from the previously reported (diamino­methyl­idene)sulfonium chloride–thio­urea (3/2) salt [Zouihri (2012b ?). Acta Cryst. E68, o257]. The NiII ion is coordinated in a distorted tetra­hedral geometry by two mol­ecules of thio­urea [Ni—S = 2.3079?(7) and 2.3177?(6)?Å] and two chloride anions [Ni—Cl = 2.2516?(7) and 2.2726?(7)?Å]. The bond angles at the Ni atom lie between 96.69?(2) and 115.40?(3)°, while the dihedral angle between the mean planes of the two thio­urea ligands is 6.36?(15)°. The crystal structure is characterized by intra- and inter­molecular N—H?Cl hydrogen bonds, which lead to the formation of two-dimensional networks lying parallel to the ab plane. The networks are linked via classical N—H?Cl and N—H?S hydrogen bonds, forming a three-dimensional arrangement.

Zouihri, Hafid

2012-01-01

391

Dichloridobis(thio-urea-?S)nickel(II).  

PubMed

The title complex, [NiCl(2)(CH(4)N(2)S)(2)], has been synthesized from the previously reported (diamino-methyl-idene)sulfonium chloride-thio-urea (3/2) salt [Zouihri (2012b ?). Acta Cryst. E68, o257]. The Ni(II) ion is coordinated in a distorted tetra-hedral geometry by two mol-ecules of thio-urea [Ni-S = 2.3079?(7) and 2.3177?(6)?Å] and two chloride anions [Ni-Cl = 2.2516?(7) and 2.2726?(7)?Å]. The bond angles at the Ni atom lie between 96.69?(2) and 115.40?(3)°, while the dihedral angle between the mean planes of the two thio-urea ligands is 6.36?(15)°. The crystal structure is characterized by intra- and inter-molecular N-H?Cl hydrogen bonds, which lead to the formation of two-dimensional networks lying parallel to the ab plane. The networks are linked via classical N-H?Cl and N-H?S hydrogen bonds, forming a three-dimensional arrangement. PMID:22412454

Zouihri, Hafid

2012-03-01

392

[Calcium antagonists: current and future applications based on new evidence. The mechanisms on lowering serum uric acid level by calcium channel blockers].  

PubMed

In hypertensive subjects, their serum uric acid levels tend to be higher because of decreasing urinary secretion or overproduction of uric acid. Among calcium channel blockers (CCBs) , long acting nifedipine and cilnidipine reveal serum uric acid lowering action. They decrease the production of uric acid precursor in skeletal muscles under anaerobic condition induced by hypertension or insulin resistance. Hyperuricemia is considered to be a risk factor of not only gout but also renal and cardiovascular diseases, thus, it is important to use CCBs without adverse effect on uric acid metabolisms. PMID:20048433

Mizuta, Einosuke; Hamada, Toshihiro; Igawa, Osamu; Shigemasa, Chiaki; Hisatome, Ichiro

2010-01-01

393

Long-Term Regulation of Renal Urea Transporters during Antidiuresis  

PubMed Central

To produce a concentrated urine, the renal medulla needs hypertonicity for the reabsorption of free water from collecting duct. The single effect that increases interstitial tonicity in the outer medulla is the active NaCl reabsorption in the thick ascending limb, while the single effect in the inner medulla is the passive efflux of NaCl through the thin ascending limb. The passive mechanism in the inner medulla requires high interstitial urea concentration. Two main groups of urea transporters (UT-A, UT-B) are present in the kidney, which maintains the high concentration of urea in the deepest portion of the inner medulla by intra-renal urea recycling. Recent studies suggest that UT-A1 in the terminal inner medullary collecting duct is up-regulated when urine or inner medullary interstitial urea is depleted in order to enhance the reabsorption of urea, while UT-A2 in the descending thin limb of loops of Henle and UT-B in the descending vasa recta are increased when outer medullary interstitial urea concentration is high, in order to prevent the loss of urea from the medulla to the systemic circulation, thereby increasing intra-renal urea recycling. This review will summarize the functions of the renal urea transporters in urine concentration mechanism and the recent knowledge about their long-term regulation.

2006-01-01

394

Uric acid deposits and estivation in the invasive apple-snail, Pomacea canaliculata  

Microsoft Academic Search

The physiological ability to estivate is relevant for the maintenance of population size in the invasive Pomacea canaliculata. However, tissue reoxygenation during arousal from estivation poses the problem of acute oxidative stress. Uric acid is a potent antioxidant in several systems and it is stored in specialized tissues of P. canaliculata. Changes in tissue concentration of thiobarbituric acid reactive substances

Maximiliano Giraud-Billoud; María A. Abud; Juan A. Cueto; Israel A. Vega; Alfredo Castro-Vazquez

2011-01-01

395

Free Radical Scavenging, DNA Protection, and Inhibition of Lipid Peroxidation Mediated by Uric Acid  

Microsoft Academic Search

Uric acid (UA) has been proposed to be the dominant antioxidant in birds. The objective of this study was to investigate the quenching effect of varying concentrations of UA, including those found in avian plasma, on specific reactive oxygen species (ROS) and to determine the ability of UA to protect DNA and cellular membranes from ROS-mediated damage. Hydroxyl (•OH) and

Beth Stinefelt; Stephen S. Leonard; Kenneth P. Blemings; Xianglin Shi; Hillar Klandorf

2005-01-01

396

CuO thin film based uric acid biosensor with enhanced response characteristics.  

PubMed

An efficient reagentless uric acid biosensor has been realized using a copper oxide (CuO) thin film matrix grown onto platinum (Pt) coated corning glass substrates by pulsed laser deposition (PLD) technique. The p-type CuO matrix successfully introduces redox property in the electrode and provides enhanced electron communication features. Sensing response obtained by the bioelectrocatalytic oxidation of uric acid by uricase/CuO/Pt/glass electrode was studied without any external mediator using cyclic voltammetry (CV) and photometric assay. The studies reveal that the uricase/CuO/Pt/glass bio-electrode exhibits good linearity over a wide range of 0.05 mM to 1.0mM uric acid concentration with enhanced response of 2.7 mA/mM and high shelf life (>14 weeks). A low Michaelis-Menten constant (K(m)) of 0.12 mM, indicate that the immobilized enzyme (uricase) has enhanced affinity towards its analyte (uric acid). The results confirm promising application of the p-type CuO thin film matrix for the realization of a reagentless integrated implantable biosensor. PMID:22647533

Jindal, Kajal; Tomar, Monika; Gupta, Vinay

2012-01-01

397

Inhibition of bovine kidney low molecular mass phosphotyrosine protein phosphatase by uric acid.  

PubMed

Uric acid inhibited 50% of the activity of bovine kidney low molecular mass phosphotyrosine protein phosphatase at concentrations of 1.0, 0.4, 1.3, and 0.2 mM, respectively for p-nitrophenyl phosphate (p-NPP), flavine mononucleotide, beta-naphthyl phosphate and tyrosine phosphate (Tyr-P) as substrates. The mixed type inhibition of p-NPP hydrolysis was fully reversible, with Kic and Kiu values of 0.4 and 1.1 mM, respectively; the inhibition by uric acid shifted the pH optimum from 5.0 to 6.5. When Tyr-P was the substrate, competitive inhibition was observed with a Ki value of 0.05 mM. Inhibition studies by uric acid in the presence of thiol compounds, and preincubation studies in the presence of inorganic phosphate suggest that the interaction of uric acid with the enzyme occurred at the active site, but did not involve SH residues, and that the mechanism of inhibition depended on the structure of the substrates. PMID:12683751

Granjeiro, José Mauro; Ferreira, Carmen Verissima; Granjeiro, Paulo Afonso; Da Silva, Cinthia Celestino; Taga, Eulázio Mikio; Volpe, Pedro Luiz Onofre; Aoyama, Hiroshi

2002-10-01

398

Influence of Recanalization on Uric Acid Patterns in Acute Ischemic Stroke  

Microsoft Academic Search

Background: Most epidemiological studies have reported a significant association between elevated serum levels of uric acid (UA) and increased cardiovascular disease. On the other hand, UA is the most abundant antioxidant in the human body. We hypothesized that UA levels would change noticeably in association with the degree of oxidative stress in acute ischemic stroke. Methods: We analyzed consecutive patients

Ji Man Hong; Oh Young Bang; Chin-Sang Chung; In Soo Joo; Byoung Joo Gwag; Bruce Ovbiagele

2010-01-01

399

Serum uric acid and cardiovascular disease: Recent developments, and where do they leave us?  

Microsoft Academic Search

The relationship between serum uric acid (SUA) and cardiovascular disease has been controversial. Here we review recent literature assessing whether hyperuricemia is an independent risk factor for adverse cardiovascular outcomes. Studies from the past 6 years evaluating the association of SUA with cardiovascular disease were identified through MEDLINE, EMBASE, and Cochrane library searches, bibliography cross-referencing, and review articles. Twenty-one cohort

Joshua F. Baker; Eswar Krishnan; Lan Chen; H. Ralph Schumacher

2005-01-01

400

Uric acid in chronic heart failure: a marker of chronic inflammation  

Microsoft Academic Search

Background Chronic heart failure is associated with hyperuricaemia and elevations in circulating markers of inflammation. Activation of xanthine oxidase, through free radical release, causes leukocyte and endothelial cell acti- vation. Associations could therefore be expected between serum uric acid level, as a marker of increased xanthine oxidase activity, and markers of inflammation. We have explored these associations in patients with

F. Leyva; S. D. Anker; I. F. Godsland; M. Teixeira; P. G. Hellewell; W. J. Kox; P. A. Poole-Wilson; A. J. S. Coats

1998-01-01

401

Uric Acid, Hominoid Evolution, and the Pathogenesis of Salt-Sensitivity  

Microsoft Academic Search

Humans have elevated serum uric acid as a result of a mutation in the urate oxidase (uricase) gene that occurred during the Miocene. We hypothesize that the mutation provided a survival advantage because of the ability of hyperuricemia to maintain blood pressure under low-salt dietary conditions, such as prevailed during that period. Mild hyperuricemia in rats acutely increases blood pressure

Susumu Watanabe; Duk-Hee Kang; Lili Feng; Takahiko Nakagawa; John Kanellis; Hui Lan; Marilda Mazzali; Richard J. Johnson

2010-01-01

402

Is There a Pathogenetic Role for Uric Acid in Hypertension and Cardiovascular and Renal Disease?  

Microsoft Academic Search

Hyperuricemia is associated with hypertension, vascular disease, renal disease, and cardiovascular events. In this report, we review the epidemiologic evidence and potential mechanisms for this association. We also summarize experimental studies that demonstrate that uric acid is not inert but may have both beneficial functions (acting as an antioxidant) as well as detrimental actions (to stimulate vascular smooth muscle cell

Richard J. Johnson; Duk-Hee Kang; Daniel Feig; Salah Kivlighn; John Kanellis; Susumu Watanabe; Katherine R. Tuttle; Bernardo Rodriguez-Iturbe; Jaime Herrera-Acosta; Marilda Mazzali

2010-01-01

403

Volatile disinfection byproducts resulting from chlorination of uric acid: implications for swimming pools.  

PubMed

Cyanogen chloride (CNCl) and trichloramine (NCl3) are important disinfection byproducts in chlorinated swimming pools. However, some unknowns exist regarding the precursors of their formation. In this study, uric acid is shown to be an efficient precursor to formation of CNCl and NCl3. The molar yields of CNCl and NCl3 were observed to be as high as 44% (pH = 6.0, chlorine/precursor molar ratio [Cl/P] = 6.4) and 108% (pH = 7.0, Cl/P = 30), respectively, both being strong functions of Cl/P, pH, and temperature. Analysis of swimming pool water samples, combined with the results of experiments involving chlorination of uric acid, and chlorination of body fluid analog mixtures, indicated that uric acid chlorination may account for a large fraction of CNCl formation in swimming pools. Moreover, given that uric acid introduction to pools is attributable to urination, a voluntary action for most swimmers, these findings indicate important benefits to pool water and air chemistry that could result from improved hygiene habits on the part of swimmers. PMID:24568660

Lian, Lushi; E, Yue; Li, Jing; Blatchley, Ernest R

2014-03-18

404

Serum Uric Acid, Hyperuricemia and Body Mass Index in Children and Adolescents with Intellectual Disabilities  

ERIC Educational Resources Information Center

The aims of the preset study were to describe the profile of serum uric acid, the prevalence of hyperuricemia and its risk factors among children and adolescents with intellectual disabilities. We conducted a cross-sectional study of 941 children and adolescents with intellectual disabilities (aged 4-18 years) who participated in annual health…

Lin, Jin-Ding; Lin, Pei-Ying; Lin, Lan-Ping; Hsu, Shang-Wei; Yen, Chia-Feng; Fang, Wen-Hui; Wu, Sheng-Ru; Chien, Wu-Chien; Loh, Ching-Hui; Chu, Cordia M.

2009-01-01

405

Effect of Uricosuric Drug Administration on Uric Acid Levels in Unstimulated Parotid Fluid.  

National Technical Information Service (NTIS)

Parotid fluid was collected twice daily without exogenous stimulation from 6 healthy young adult males, both before and during a 5-day period of uricosuric drug dosage. A highly significant decrease in serum uric acid concentration was brought about by dr...

I. L. Shannon H. H. Chauncey

1967-01-01

406

Serum Uric Acid, Cholesterol, and Psychological Moods Throughout Stressful Naval Training.  

National Technical Information Service (NTIS)

Fifty-one Navy recruits, all volunteers for a preliminary underwater demolition team (UDT) training program, were followed through four weeks of training. Twenty-seven men passed and 24 failed the training course. Serum uric acid and serum cholesterol lev...

R. H. Rahe D. H. Ryman R. J. Biersner

1976-01-01

407

Graphene-carbon nanotube composite aerogel for selective detection of uric acid  

NASA Astrophysics Data System (ADS)

Graphene and single-walled carbon nanotube (SWNT) composite aerogel has been prepared by hydrothermal synthesis. The restacking of graphene is effectively reduced by SWNTs inserted in between graphene layers in order to make available more active sites and reactive surface area. Electrochemical experiments show that the graphene-SWNT composite electrode has superior catalytic performance in selective detection of uric acid (UA).

Zhang, Feifei; Tang, Jie; Wang, Zonghua; Qin, Lu-Chang

2013-12-01

408

Spectrophotometric determination of uric acid and some redeterminations of its solubility  

USGS Publications Warehouse

The present study was initiated in order to develop a rapid and accurate method for the determination of uric acid in fresh, brackish, and sea water. It was found that the spectrophotometric determination of uric acid based upon its reaction with arsenophosphotungstic acid reagent in the presence of cyanide ion meets this objective. The absorbancy of the blue complex was measured at 890 m??. Slight variations from Beer's law were generally found. The results show the effects of pH, reaction time, concentration of reagents, and temperature upon color development and precipitate formation. Disodium dihydrogen ethylenediamine tetraacetate (Versene) was used as a buffering and complexirig agent. The results are significant in that they give the absorption spectrum of the blue complex and the effects of variables upon its absorbancy. Studies were made with the method to determine the stability of reagents and standard solutions and to determine the rate of bacterial decomposition of uric acid. Measurements of the solubility of uric acid are reported.

Norton, D. R.; Plunkett, M. A.; Richards, F. A.

1954-01-01

409

Further characterization of photothermal breakdown products of uric acid stones following holmium:YAG laser lithotripsy  

NASA Astrophysics Data System (ADS)

Previously we found that Ho:YAG laser (2120 nm) lithotripsy of uric acid stones produced cyanide, a known thermal breakdown product of uric acid. We now report that alloxan, another thermal breakdown product, is also likely produced. Uric acid stones (approximately 98% pure) of human origin were placed in distilled water and subjected to one of the following experimental treatments: unexposed control, exposed to Ho:YAG laser, Nd:YAG laser, or mechanically crushed. Samples were then processed for HPLC analysis with UV detection. Peaks were identified by comparison to authentic standards. All samples contained uric acid, with retention time (RT) about 6 min. All of the laser-exposed samples contained a peak that eluted at 2.5 min, identical to the RT of authentic alloxan. Ho:YAG laser irradiation, however, produced a larger presumed alloxan peak than did the Nd:YAG laser. The peak at 2.5 min, as well as unidentified later-eluting peaks, were present in the laser-exposed, but not the unexposed or mechanically crushed, samples. These results confirm the thermal nature of lithotripsy performed with long-pulse IR lasers.

Glickman, Randolph D.; Weintraub, Susan E.; Kumar, Neeru; Corbin, Nicole S.; Lesani, Omid; Teichman, Joel M.

2000-06-01

410

Adaptation to multiday ozone exposure is associated with a sustained increase of bronchoalveolar uric acid.  

PubMed

The phenomenon of ozone tolerance is described, but the underlying mechanisms remain unknown. We tested whether adaptation to multiday ozone exposure was related to an upregulated pulmonary antioxidant defence. Six calves were exposed to 0.75 ppm ozone, 12 h day(-1) for seven consecutive days. Pulmonary function tests and bronchoalveolar lavage (BAL) were performed before, after the first (D1), third (D3) and seventh (D7) exposure. Differential cell count, total proteins, 8-epi-PGF2alpha, glutathione and uric acid were determined in BAL. Dynamic lung compliance and arterial oxygen tension were significantly decreased and lung oedema impaired pulmonary function on D1. By repeating ozone exposures, progressive functional adaptation occurred. Ozone induced a significant increase of BAL neutrophil percentage on D1. On D3 and D7, neutrophil percentage was progressively decreased, but remained significantly elevated. BAL total proteins were significantly increased on D1 and decreased progressively until D7. 8-Epi-PGF2alpha was significantly increased on D1 and was returned to baseline on D3 and D7, whilst glutathione significantly increased on D3 and returned to baseline on D7. Uric acid was increased ten-fold on D1. On D3, uric acid was increased six-fold and was persistently elevated at D7. This study suggests that ozone adaptation of functional and inflammatory variables is accompanied with sustained BAL uric acid elevation. PMID:11999700

Kirschvink, Nathalie; Fiévez, Laurence; Bureau, Fabrice; Degand, Guy; Maghuin-Rogister, Guy; Smith, Nicola; Art, Tatiana; Lekeux, Pierre

2002-01-01

411

Dietary fructose in relation to blood pressure and serum uric acid in adolescent boys and girls.  

PubMed

Evidence that fructose intake may modify blood pressure is generally limited to adult populations. This study examined cross-sectional associations between dietary intake of fructose, serum uric acid and blood pressure in 814 adolescents aged 13-15 years participating in the Western Australian Pregnancy Cohort (Raine) Study. Energy-adjusted fructose intake was derived from 3-day food records, serum uric acid concentration was assessed using fasting blood and resting blood pressure was determined using repeated oscillometric readings. In multivariate linear regression models, we did not see a significant association between fructose and blood pressure in boys or girls. In boys, fructose intake was independently associated with serum uric acid (P<0.01), and serum uric acid was independently associated with systolic blood pressure (P<0.01) and mean arterial pressure (P<0.001). Although there are independent associations, there is no direct relationship between fructose intake and blood pressure. Our data suggest that gender may influence these relationships in adolescence, with significant associations observed more frequently in boys than girls. PMID:22971754

Bobridge, K S; Haines, G L; Mori, T A; Beilin, L J; Oddy, W H; Sherriff, J; O'Sullivan, T A

2013-04-01

412

Serum biochemical values of farmed ostrich (Struthio camelus) in Botswana.  

PubMed

Reference biochemical values for serum analytes of 126 clinically normal farmed ostriches on one farm in Botswana were established. These included sodium, potassium, chloride, total protein, albumin, urea, creatinine, uric acid, cholesterol, total bilirubin, conjugated bilirubin, glucose, triglyceride, calcium, phosphorus, manganese, copper, zinc, alkaline phosphatase, gamma glutamyl transferase and creatinine kinase. The values obtained in this study can be used as reference values. PMID:9809323

Mushi, E Z; Binta, M G; Chabo, R G; Isa, J F; Modisa, L

1998-09-01

413

Plasma uric acid level indicates tubular interstitial leisions at early stage of IgA nephropathy  

PubMed Central

Background Hyperuricemia appeared to be a common symptom in IgA nephropathy (IgAN), even in those with normal eGFR. IgAN was characterized by variation of pathological features, especially variable tubulointerstitial lesions. Since tubular reabsorption and excretion appeared to be more important in determination of plasma uric acid levels in persons without obvious decrease of glomerular filtration rate, we took advantage of our IgAN cohort to investigate whether plasma uric acid level associated with tubular interstitial lesions, and could be considered as a maker for tubular interstitial lesions, especially at early stage with normal eGFR. Methods 623 IgAN patients were involved in the present study. Morphological changes were evaluated with Oxford classification scoring system as well as Beijing classification system of IgAN. Statistical analysis was done with SPSS 13.0. Results We found that plasma uric acid level associated with percentage of interstitial fibrosis/tubular atrophy. Higher plasma uric acid levels indicated higher tubulointerstitial scores, either with Oxford system (P?=?0.012) or with Beijing classification system (P?=?4.8*10-4) in the whole cohort. We also found that in the subgroup of 258 IgAN cases with normal baseline eGFR (eGFR?>?=90 ml/min/1.73 M2), higher plasma uric acid associated with more severe tubulointerstitial lesions with Beijing scoring system (P?=?3.4*10-5). The risk of having more than 10% tubulointerstitial lesions in patients with hyperuricemia increased 58% compared with normal uric acid level. In subgroup with normal eGFR, only hyperuricemia predicted tubulointerstitial leisions, and the risk of having more tubulointerstitial changes increased 100%. Among these patients, hyperuricemia was associated with more tubulointerstitial lesions with a specificity of 60.3%. Specificity increased to 65% among those patients with eGFR?>?=90 ml/min/1.73 m2. Conclusions Plasma uric acid levels indicate tubular interstitial lesions in IgAN and hyperuricemia may be considered as a marker for tubulointerstitial lesions.

2014-01-01

414

Uric acid concentration in subjects at risk of type 2 diabetes mellitus: relationship to components of the metabolic syndrome.  

PubMed

High uric acid concentration is a common finding in subjects with risk factors for cardiovascular disease (CVD), including some characteristics of the metabolic syndrome. However, its exact role in this setting and in the progression to type 2 diabetes mellitus (DM) is not well understood and could be affected by confounding factors such as hypertriglyceridemia. Our study aimed to establish the relationship between uric acid (avoiding the interference of high triglyceride levels), insulin sensitivity, and components of the metabolic syndrome in a group of subjects at high risk of developing DM. Among 201 subjects included in the study, 111 (55.2%) showed an abnormal oral glucose tolerance and uric acid levels higher than those measured in subjects with normal glucose tolerance. Body mass index (BMI), triglycerides, diastolic blood pressure (DBP), and 2-hour glycemia in the oral glucose tolerance test (OGTT) contributed independently to uric acid concentration (R2 =.59). However, uric acid did not affect either insulin sensitivity or glucose tolerance. The recovery tests revealed that a triglyceride concentration > or = 3 mmol/L interfered with the measurement of uric acid level when a colorimetric method was used, but not when a dry-chemistry method was used. In conclusion, uric acid concentration is higher in subjects at high risk of DM with abnormal glucose tolerance and is independently determined by various components of the metabolic syndrome. PMID:11887176

Costa, A; Igualá, I; Bedini, J; Quintó, L; Conget, I

2002-03-01

415

Inhibition of UV-induced uric acid production using allopurinol prevents suppression of the contact hypersensitivity response.  

PubMed

Exposure to solar ultraviolet (UV) radiation suppresses adaptive immune responses. This contributes to skin carcinogenesis but may protect from some autoimmune diseases. However, the molecular changes occurring within UV-exposed skin that precipitate the downstream events leading to immune suppression are not fully understood. Using a combination of in vitro and in vivo mouse models, we have discovered that UV induces significant cutaneous production of immune suppressive uric acid. The ability of UV-induced uric acid to inhibit a contact hypersensitivity response was successfully blocked by the gout-treating drug Allopurinol. Up-regulation of NLRP3 mRNA by UV was also found to be dependent on UV-induced uric acid. This suggested that the target of UV-induced uric acid included proteins involved in the formation and activation of the NLRP3-inflammasome. However, in contrast to NLRP3, the adaptor protein ASC, which is required for formation of the NLRP3-inflammasome, was significantly down-regulated. Furthermore, this down-regulation was not dependent on UV-induced uric acid production because Allopurinol treatment failed to prevent the reduction in ASC. Hence, our results identify uric acid as an important molecule involved in sterile UV-induced inflammation and immune suppression. UV-induced uric acid may therefore offer a unique therapeutic target for preventing and treating skin cancer. PMID:23387472

Leighton, Sarah; Kok, Lai-Fong; Halliday, Gary M; Byrne, Scott N

2013-03-01

416

Use of urine albumin/creatinine ratio for estimation of proteinuria in cats and dogs.  

PubMed

The clinical utility of the urine albumin/creatinine ratio (UAC) using a simplified analyzer for estimation of proteinuria was studied in cats and dogs. Measurement results for diluted feline and canine albumin standard solutions showed linearity. Although conversion formulas (y=1.28x+1.04 and y=1.67x+10.47 for cats and dogs, respectively) were necessary, urine albumin concentrations could be determined in both animals. In cats and dogs with proteinuria, the UAC changed parallel with the urine protein/ creatinine ratio (UPC), and the Log UAC and Log UPC were significantly correlated (r=0.803 (p<0.01) in cats, r=0.801 (p<0.01) in dogs). The UAC using an UAC analyzer could be used clinically as one of the basic in-hospital laboratory tests for estimation of proteinuria in cats and dogs. PMID:18772568

Kuwahar, Yasuhito; Nishii, Naohito; Takasu, Masaki; Ohba, Yasunori; Maeda, Sadatoshi; Kitagawa, Hitoshi

2008-08-01

417

Relation of albumin\\/creatinine ratio to C-reactive protein and to the metabolic syndrome  

Microsoft Academic Search

We hypothesized that the association of high sensitivity C-reactive protein (CRP) with urinary albumin excretion (UAE) is predominately mediated through its correlation with the metabolic syndrome. Serum CRP and urine albumin:creatinine ratios (ACR) from 720 preventive cardiology patients were analyzed to estimate age- and gender-adjusted relative risk of high CRP and metabolic syndrome for high ACR. These data demonstrate that

Adrian W. Messerli; Niranjan Seshadri; Gregory L. Pearce; Ravish Sachar; Byron J. Hoogwerf; Dennis L. Sprecher

2003-01-01

418

Association between urinary sodium, creatinine, albumin, and long-term survival in chronic kidney disease.  

PubMed

Dietary sodium intake is associated with hypertension and cardiovascular risk in the general population. In patients with chronic kidney disease, sodium intake has been associated with progressive renal disease, but not independently of proteinuria. We studied the relationship between urinary sodium (UNa) excretion and UNa to creatinine ratio and mortality or requirement for renal replacement therapy in chronic kidney disease. Adult patients attending a renal clinic who had ?1 24-hour UNa measurement were identified. Twenty-four-hour UNa measures were collected and UNa to creatinine ratio calculated. Time to renal replacement therapy or death was recorded. Four hundred twenty-three patients were identified with mean estimated glomerular filtration rate of 48 mL/min per 1.73 m(2). Ninety patients required renal replacement therapy and 102 patients died. Mean slope decline in estimated glomerular filtration rate was -2.8 mL/min per 1.73 m(2) per year. Median follow-up was 8.5 years. Patients who died or required renal replacement therapy had significantly higher UNa excretion and UNa to creatinine ratio, but the association with these parameters and poor outcome was not independent of renal function, age, and albuminuria. When stratified by albuminuria, UNa to creatinine ratio was a significant cumulative additional risk for mortality, even in patients with low-level albuminuria. There was no association between low UNa and risk, as observed in some studies. This study demonstrates an association between UNa excretion and mortality in chronic kidney disease, with a cumulative relationship between sodium excretion, albuminuria, and reduced survival. These data support reducing dietary sodium intake in chronic kidney disease, but additional study is required to determine the target sodium intake. PMID:24732890

McQuarrie, Emily P; Traynor, Jamie P; Taylor, Alison H; Freel, E Marie; Fox, Jonathan G; Jardine, Alan G; Mark, Patrick B

2014-07-01

419

Biomarkers and creatinine in AKI: the trough of disillusionment or the slope of enlightenment?  

PubMed

Assessment of acute kidney biomarkers against changes in plasma creatinine is beset by issues of heterogeneity of study cohorts and timing of sampling. Siew and colleagues attempt to minimize these issues in a case-control study of three biomarkers in the intensive care unit. The results highlight the inherent methodological difficulties and the need to reference structural injury biomarkers against more meaningful outcomes. PMID:24080874

Endre, Zoltán H; Pickering, John W

2013-10-01

420

Inflammation and dietary protein intake exert competing effects on serum albumin and creatinine in hemodialysis patients  

Microsoft Academic Search

Inflammation and dietary protein intake exert competing effects on serum albumin and creatinine in hemodialysis patients.BackgroundCross-sectional studies have shown an inverse correlation between serum C-reactive protein (CRP) and serum albumin concentration in hemodialysis patients. The net effects of inflammation and dietary protein intake on nutritional markers over time are unknown.MethodsTo explore the effects of CRP and normalized protein catabolic rate

George A Kaysen; Glenn M Chertow; Rohini Adhikarla; Belinda Young; Claudio Ronco; Nathan W Levin

2001-01-01