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1

Plasma urea, creatinine and uric acid concentrations in response to dehydration in racing pigeons (Columba Livia Domestica)  

Microsoft Academic Search

Plasma urea, creatinine and uric acid concentrations were determined in six racing pigeons that had been deprived of water for 3 days. Plasma urea concentration showed a 6.5? to 15.3?fold increase, creatinine a 1.2? to 1.5?fold increase and uric acid a 1.4? to 2?fold increase when compared with values before water deprivation. Although these increases were significant, plasma urea and

J. T. Lumeij

1987-01-01

2

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

3

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

4

The effects of a probiotic on blood urea nitrogen and creatinine concentrations in large felids.  

PubMed

Chronic kidney disease is a common finding in older captive exotic felids. The purpose of this study was to evaluate the effectiveness of a probiotic to reduce blood urea nitrogen and creatinine in large felids. Fifteen adult, large felids (6 tigers [Panthera tigris], 5 lions [Panthera leo], 3 cougars [Puma concolor], and 1 leopard [Panthera pardus]) were administered a probiotic twice daily after a baseline complete blood cell count and plasma chemistry panel was obtained. Plasma chemistry values were rechecked at 2 mo (n = 14) and 6 mo (n = 9). There was no significant change in blood urea nitrogen over time; however, there was a significant change in creatinine over time (P = 0.04). Creatinine concentration decreased significantly between 2 and 6 mo (P = 0.02), and a decrease was seen between 0 and 6 mo, but this change was not significant (P = 0.05). There was no significant difference noted for creatinine concentration between 0 and 2 mo (P = 0.35). This probiotic may be helpful in large felids with elevated creatinine concentrations because of chronic kidney disease; however, further studies are warranted. PMID:22950314

McCain, Stephanie; Allender, Matthew C; Schumacher, Juergen; Ramsay, Edward

2011-09-01

5

Improved HPLC method for the simultaneous determination of allantoin, uric acid and creatinine in cattle urine  

Microsoft Academic Search

An HPLC procedure developed for the rapid and simultaneous determination of purine derivatives (PD) in ruminants’ urine was investigated, since the adoption of a single method for the simultaneous detection of PD and creatinine was not carried out due to elution of polar co-extractives and also due to overlapping of the peaks of allantoin and creatinine. The experimental conditions chosen

S. K. George; M. T. Dipu; U. R. Mehra; P. Singh; A. K. Verma; J. S. Ramgaokar

2006-01-01

6

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. PMID:22754258

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

2012-01-01

7

Comparing the effects of salts of diclofenac and alminoprofen with aspirin on serum electrolytes, creatinine and urea levels in rabbits.  

PubMed

The effects of diclofenac sodium, diclofenac potassium, alminoprofen and aspirin on serum electrolytes (serum Na(+) and K(+)), urea and creatinine were compared in rabbits in acute and chronic phases of treatment. The data suggested that all the four drugs markedly increased the serum electrolytes, urea and creatinine levels in both post-treatment phases. In conclusion, present study does not present any advantage of diclofenac sodium over diclofenac potassium at electrolyte levels on short and long term treatment. Nevertheless, current data support the evidence of renal function impairment by all the four drug therapies used in the present study, which is generally caused by NSAIDS. PMID:23009994

Syed, Nawazish-I-Husain; Zehra, Farnaz; Syed, Amir Ali-Rizvi; Karim, Sabiha; Khan, Farrakh Zia

2012-10-01

8

Simultaneous determination of plasma creatinine, uric acid, kynurenine and tryptophan by high-performance liquid chromatography: method validation and in application to the assessment of renal function.  

PubMed

A high-performance liquid chromatography with ultraviolet detection method has been developed for the simultaneous determination of a set of reliable markers of renal function, including creatinine, uric acid, kynurenine and tryptophan in plasma. Separation was achieved by an Agilent HC-C18 (2) analytical column. Gradient elution and programmed wavelength detection allowed the method to be used to analyze these compounds by just one injection. The total run time was 25?min with all peaks of interest being eluted within 13?min. Good linear responses were found with correlation coefficient >0.999 for all analytes within the concentration range of the relevant levels. The recovery was: creatinine, 101 ± 1%; uric acid, 94.9 ± 3.7%; kynurenine, 100 ± 2%; and tryptophan, 92.6 ± 2.9%. Coefficients of variation within-run and between-run of all analytes were ?2.4%. The limit of detection of the method was: creatinine, 0.1?µmol/L; uric acid, 0.05?µmol/L; kynurenine, 0.02?µmol/L; and tryptophan, 1?µmol/L. The developed method could be employed as a useful tool for the detection of chronic kidney disease, even at an early stage. Copyright © 2014 John Wiley & Sons, Ltd. PMID:25042392

Zhao, Jianxing

2015-03-01

9

Effects of Bed-Rest on Urea and Creatinine: Correlation with Changes in Fat-Free Mass  

PubMed Central

Background Bed-rest experiments are designed for investigation on catabolic effects of hypokinetic conditions and/or for microgravity simulation in on-ground aerospace research. Bed-rest effects include a reduction in fat-free mass and muscle mass. Urea and creatinine are catabolites of endogenous protein and of muscular energetic metabolism which are excreted mainly by the kidney. The study investigated on urea, creatinine, and kidney function during bed-rest. Methods Twenty healthy young men underwent a 7-day adaptation period (day-6 to day-0) and a 35-day bed-rest experiment (day1 to day35) during normocaloric diet. Urine were collected from day-3 to day0 (baseline) and from day1 to day35. Blood samples and anthropometrical data were collected at day0 (baseline) and bed-rest days 7, 14, 21, 28, and 35. Results Bed-rest reduced plasma volume, weight, fat-free mass, and muscle mass (P<0.001). During bed-rest there was a transient increase in plasma and urinary urea, a decrease in plasma creatinine, and no change in urinary creatinine. The overall integral of changes from day0 to day35 was on average +101.7 mg/dL for plasma urea (95%CI?=?+43.4/+159.9), +82.2 g/24 h for urinary urea (95%CI?=?+55.8/+108.7), ?2.5 mg/dL for plasma creatinine (95%CI?=??3.1/?1.9). Bed-rest reduced plasma cistatyn C also, which was used as mass-independent marker of glomerular filtration rate (?13.1%, P<0.05). Correlations with final reduction in fat-free mass and muscle mass were significant for the overall integral of changes in urinary urea from day0 to day35 (R?=?0.706, P<0.001) and for early changes in urinary urea and plasma urea from day0 to day7 (R?=?0.566, P?=?0.009 and R?=?0.715, P<0.001, respectively). Conclusions Study results shows that urea is a marker of catabolic conditions secondary to hypokinetic conditions. PMID:25265226

Bilancio, Giancarlo; Lombardi, Cinzia; Pisot, Rado; De Santo, Natale G.; Cavallo, Pierpaolo; Cirillo, Massimo

2014-01-01

10

Establishing Standards for Studying Renal Function in Mice through Measurements of Body Size-Adjusted Creatinine and Urea Levels  

PubMed Central

Strategies for obtaining reliable results are increasingly implemented in order to reduce errors in the analysis of human and veterinary samples; however, further data are required for murine samples. Here, we determined an average factor from the murine body surface area for the calculation of biochemical renal parameters, assessed the effects of storage and freeze-thawing of C57BL/6 mouse samples on plasmatic and urinary urea, and evaluated the effects of using two different urea-measurement techniques. After obtaining 24?h urine samples, blood was collected, and body weight and length were established. The samples were evaluated after collection or stored at ?20°C and ?70°C. At different time points (0, 4, and 90 days), these samples were thawed, the creatinine and/or urea concentrations were analyzed, and samples were restored at these temperatures for further measurements. We show that creatinine clearance measurements should be adjusted according to the body surface area, which was calculated based on the weight and length of the animal. Repeated freeze-thawing cycles negatively affected the urea concentration; the urea concentration was more reproducible when using the modified Berthelot reaction rather than the ultraviolet method. Our findings will facilitate standardization and optimization of methodology as well as understanding of renal and other biochemical data obtained from mice. PMID:25243193

Rodrigues, Wellington Francisco; Miguel, Camila Botelho; Napimoga, Marcelo Henrique; Oliveira, Carlo Jose Freire; Lazo-Chica, Javier Emilio

2014-01-01

11

Application of reflectance spectroscopy to the estimation of uric acid, urea and glucose: an evaluation of the Ames Seralyzer  

PubMed Central

An original approach to the measurement of analytes in clinical chemistry has now become available, in which dry reagent strip technology is linked to measurement by reflectance spectroscopy. The present studies have evaluated the performance of the first of these test systems—for uric acid, urea and glucose, in serum—by comparison with conventional liquid chemistry methods. Satisfactory performance in terms of both precision and accuracy was obtained for all three test systems, the current “state-of-the-art” performance criteria being met; the Seralyzer system proved reliable and easy to use in the hands of trained operators. It should find a place as a “Stat” analyser in the laboratory, in specified wards and in Health Centres. PMID:6822683

Stevens, JF; Newall, RG

1983-01-01

12

Interrelationship of ?eta-2 microglobulin, blood urea nitrogen and creatinine in streptozotocin-induced diabetes mellitus in rabbits  

PubMed Central

Measurement of serum creatinine (Cr) and blood urea nitrogen (BUN) are used as indicators of glomerular filtration rate. The increased levels of these biomarkers are usually detectable at advanced stages of kidney complications. The aim of this study was to find the interrelationship of beta-2 microglobulin (?2M), BUN and Cr in streptozotocin (STZ)-induced diabetes mellitus in rabbits. Diabetes was induced by a single intraperitoneal (IP) injection of 65 mg kg-1 of STZ in rabbits. The levels of serum insulin, glucose and three above mentioned biomarkers were measured one day before (day -1) and on days 1-3 after injection of STZ and continued weekly to the end of the experiment (12 weeks). A statistically significant increase of serum ?2M, BUN, Cr and glucose levels, and a significant decrease of insulin levels were observed in diabetic animals. However, ?2M levels increased as early as one day after STZ injection compared to Cr and BUN that elevated at day two, suggesting a probable diagnostic advantage of ?2M over currently used biomarkers in diabetic related kidney complications.

Javadi, Shahram; Asri-Rezaei, Siamak; Allahverdizadeh, Maryam

2014-01-01

13

Relationship between blood urea, protein, creatinine, triglycerides and macro-mineral concentrations with the quality and quantity of milk in dairy Holstein cows  

PubMed Central

Seventy six high and low producer cows were selected to determine the composition of the blood and milk parameters, and their interrelationships to determine the indices which could be useful to improve the milk yield. The highest mean blood concentrations were found in high producer cows. Mean values for blood urea nitrogen (BUN), serum protein (SPtn), creatinine, triglycerides (TGs), cholesterol, and beta-hydroxybutyric acid (BHB) were 25.10 mg dL-1, 10.15 g dL-1, 0.81, 62.30, 177.10 and 0.16 mmol L-1, and for macro-minerals including SCa, SMg, serum in-organic phosphorus (SIP), SNa and SK were 3.85, 2.66, 4.63, 108.00 and 4.34 mmol L-1, respectively. The highest concentrations for milk parameters, were observed in the high producers, and were significant only for MCa, MIP and MMg. Mean values for milk urea nitrogen (MUN), milk protein (MPtn) and lactose were 19.90 mg dL-1, 0.39 g dL-1, and 4.12% and for macro-minerals, 13.24, 3.88, 11.03, 73.30 and 16.90 mmol L-1, respectively. There were significant positive correlations between the blood and milk parameters except for creatinine/BHB, TGs/cholesterol and MNa/MK which were not significant. The correlations between the blood parameters were greater than in the milk parameters. Creatinine and SPtn, MUN and MPtn were the main parameters in that the relationships between MPtn with BUN, SPtn and creatinine were more noticeable than others. The regression analysis showed that BUN with the SIP and creatinine, MPtn with the BUN and creatinine and MUN with the SIP and SMg were the appropriate parameters in improvement studies related to the milk yield. In conclusion, BUN, SPtn, MUN and MPtn concentrations are the most effective indices for predicting the preferred milk yield.

Nozad, Shahram; Ramin, Ali-Gholi; Moghadam, Gholamali; Asri-Rezaei, Siamak; Babapour, Azadeh; Ramin, Sina

2012-01-01

14

Creatinine Index as a Surrogate of Lean Body Mass Derived from Urea Kt/V, Pre-Dialysis Serum Levels and Anthropometric Characteristics of Haemodialysis Patients  

PubMed Central

Background and Objectives Protein-energy wasting is common in long-term haemodialysis (HD) patients with chronic kidney disease and is associated with increased morbidity and mortality. The creatinine index (CI) is a simple and useful nutritional parameter reflecting the dietary skeletal muscle protein intake and skeletal muscle mass of the patient. Because of the complexity of creatinine kinetic modeling (CKM) to derive CI, we developed a more simplified formula to estimate CI in HD patients. Design, Setting, Participants & Measurements A large database of 549 HD patients followed over more than 20 years including monthly CKM-derived CI values was used to develop a simple equation based on patient demographics, predialysis serum creatinine values and dialysis dose (spKt/V) using mixed regression models. Results The equation to estimate CI was developed based on age, gender, pre-dialysis serum creatinine concentrations and spKt/V urea. The equation-derived CI correlated strongly with the measured CI using CKM (correlation coefficient ?=?0.79, p-value <0.001). The mean error of CI prediction using the equation was 13.47%. Preliminary examples of few typical HD patients have been used to illustrate the clinical relevance and potential usefulness of CI. Conclusions The elementary equation used to derive CI using demographic parameters, pre-dialysis serum creatinine concentrations and dialysis dose is a simple and accurate surrogate measure for muscle mass estimation. However, the predictive value of the simplified CI assessment method on mortality deserves further evaluation in large cohorts of HD patients. PMID:24671212

Canaud, Bernard; Granger Vallée, Alexandre; Molinari, Nicolas; Chenine, Leila; Leray-Moragues, Hélène; Rodriguez, Annie; Chalabi, Lotfi; Morena, Marion; Cristol, Jean-Paul

2014-01-01

15

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. PMID:23325460

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

2014-01-01

16

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. PMID:24672331

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

2014-01-01

17

Uric acid - urine  

MedlinePLUS

The urine uric acid test measures the level of uric acid in urine. Uric acid level can also be checked using a blood ... to choose the best medicine to lower uric acid level in the blood. Uric acid is a ...

18

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  

NASA Astrophysics Data System (ADS)

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.

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

2013-08-01

19

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 ... testing. The most common reason for measuring uric acid levels is in the diagnosis or treatment of ...

20

Effect of urea inclusion in diets containing corn dried distillers grains on feedlot cattle performance, carcass characteristics, ruminal fermentation, total tract digestibility, and purine derivatives-to-creatinine index.  

PubMed

Increased availability of rapidly fermentable carbohydrates and a great proportion of corn-derived CP in the diet may result in a degradable intake protein (DIP) deficit. Therefore, ruminal DIP deficit may result from high dietary inclusion of processed corn grain and small to moderate inclusion of corn distillers grains (DG). Two experiments were conducted to evaluate the effect of increasing dietary DIP concentration through the inclusion of urea on feedlot cattle performance, carcass characteristics, ruminal fermentation, total tract digestibility, and purine derivatives-to-creatinine (PDC) index. In Exp. 1, 42 steers (428 ± 5 kg initial BW) were assigned randomly to 1 of 3 diets containing (DM basis) 0 (control [CON]), 0.4 (low urea [LU]), or 0.6% urea (high urea [HU]) to provide 6.4, 7.5, or 8.0% dietary DIP, respectively, and 12% high-moisture corn (HMC), 20% corn dried DG with solubles (DDGS), 10% ryegrass haylage, 2.9% dry supplement, and dry-rolled corn (DRC). Steers were fed ad libitum once daily using a Calan gate system. Carcass-adjusted final BW and DMI were similar among treatments (P ? 0.58). Carcass-adjusted ADG was greater (P ? 0.04) for the HU diet compared with the LU and CON diets and was similar (P = 0.73) between the LU and CON diets. Carcass-adjusted G:F was greater (P = 0.03) for the HU diet compared with the LU diet, tended (P = 0.09) to be greater compared with the CON diet, and was similar (P = 0.61) between the LU and CON diets. Carcass characteristics were similar (P ? 0.34) among treatments. In Exp. 2, 4 ruminally cannulated steers (347 ± 18 kg initial BW) were randomly assigned to a replicated 2 × 2 Latin square design. Steers were fed the same CON or HU diet used in Exp. 1 ad libitum once daily. Differences in the PDC index were used as indicators of differences in microbial CP synthesis. Ruminal pH, OM intake, and starch and CP digestibility were not affected by treatment (P ? 0.13). Digestibility of OM and NDF and ruminal concentration of ammonia-N and total VFA were greater (P ? 0.04) for the HU diet compared with the CON diet. The PDC index was similar (P = 0.81) between treatments at 2 h before feed delivery: 4% lower and 14% greater for the HU diet compared with the CON diet at 4 and 10 h after feed delivery, respectively (P < 0.01). These results suggest that, due to limited DIP supplied by a DRC- and HMC-based feedlot diet containing 20% DDGS, urea supplementation resulted in improved ruminal fermentation and feed digestibility, which may explain the concurrently improved cattle performance. PMID:25412747

Ceconi, I; Ruiz-Moreno, M J; DiLorenzo, N; DiCostanzo, A; Crawford, G I

2015-01-01

21

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

22

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

23

Uric acid - blood  

MedlinePLUS

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

24

Correlation of uric acid and urinary albumin excretion rate in patients with type 2 diabetes mellitus in Taiwan  

Microsoft Academic Search

Correlation of uric acid and urinary albumin excretion rate in patients with type 2 diabetes mellitus in Taiwan.BackgroundUric acid is detrimental to the kidneys in animal models. However, its role in human diabetic nephropathy has not been extensively studied. This study evaluated the association between serum uric acid and urinary albumin-to-creatinine ratio (ACR) among patients with type 2 diabetes mellitus

CHIN-HSIAO TSENG

2005-01-01

25

Creatine and creatinine metabolism.  

PubMed

The goal of this review is to present a comprehensive survey of the many intriguing facets of creatine (Cr) and creatinine metabolism, encompassing the pathways and regulation of Cr biosynthesis and degradation, species and tissue distribution of the enzymes and metabolites involved, and of the inherent implications for physiology and human pathology. Very recently, a series of new discoveries have been made that are bound to have distinguished implications for bioenergetics, physiology, human pathology, and clinical diagnosis and that suggest that deregulation of the creatine kinase (CK) system is associated with a variety of diseases. Disturbances of the CK system have been observed in muscle, brain, cardiac, and renal diseases as well as in cancer. On the other hand, Cr and Cr analogs such as cyclocreatine were found to have antitumor, antiviral, and antidiabetic effects and to protect tissues from hypoxic, ischemic, neurodegenerative, or muscle damage. Oral Cr ingestion is used in sports as an ergogenic aid, and some data suggest that Cr and creatinine may be precursors of food mutagens and uremic toxins. These findings are discussed in depth, the interrelationships are outlined, and all is put into a broader context to provide a more detailed understanding of the biological functions of Cr and of the CK system. PMID:10893433

Wyss, M; Kaddurah-Daouk, R

2000-07-01

26

Effects of the N/L-type calcium channel blocker cilnidipine on nephropathy and uric acid metabolism in hypertensive patients with chronic kidney disease (J-CIRCLE study).  

PubMed

This study assessed the urinary albumin/creatinine ratio (ACR) and uric acid metabolism in 70 hypertensive patients with chronic kidney disease in whom urinary ACR had remained ?30 mg/g under the treatment of the L-type calcium channel blocker amlodipine. Three months after switching to the N/L-type calcium channel blocker cilnidipine, blood pressure (BP) did not change; however, urinary ACR significantly decreased with cilnidipine. Serum uric acid levels showed no significant change. In cases where uric acid production had been high (urinary uric acid/creatinine ratio ?0.5), the urinary uric acid/creatinine ratio decreased significantly after cilnidipine treatment, suggesting that cilnidipine can suppress excessive uric acid formation. These results suggest that switching from amlodipine to cilnidipine results in a significant reduction in urinary ACR as well as significant reduction in uric acid production. Thus, cilnidipine is more useful than amlodipine in improving albuminuria and uric acid metabolism in hypertensive patients with chronic kidney disease. PMID:25264215

Uchida, Shunya; Takahashi, Masato; Sugawara, Masahiro; Saito, Tomoaki; Nakai, Kazuhiko; Fujita, Masami; Mochizuki, Koichi; Shin, Isu; Morita, Takashi; Hikita, Tomoyuki; Itakura, Hironao; Takahashi, Yuko; Mizuno, Shigeki; Ohno, Yasumi; Ito, Kageki; Ito, Takafumi; Soma, Masayoshi

2014-10-01

27

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

28

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

29

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

30

Simple tests of renal function using creatinine, phenolsulphonphthalein, and pitressin  

PubMed Central

The reciprocals of the blood urea nitrogen and plasma creatinine levels, the maximum specific gravity of the urine after vasopressin, and three modified forms of the phenolsulphonphthalein (P.S.P.) excretion test were found to be directly related to the glomerular filtration rate (G.F.R.) in hospital patients. From 34 to 75 patients were studied for each test, and in 21 patients all tests were performed concurrently. The plasma creatinine level and the 15-minute urinary excretion of P.S.P. were found to be the most useful simple tests of renal function and gave sufficiently accurate estimates of total function (G.F.R.) to justify their more extensive use. The G.F.R. (ml./min./1·73 sq. m. of body surface area) could be calculated from each test, using the following equations:— [Formula: see text] G.F.R. = 3·15 × P.S.P.% + 19, where P.S.P.% is the 15-minute urinary excretion of P.S.P., expressed as a percentage of the administered dose. Satisfactory estimates of G.F.R. were also given by the simplified relationships [Formula: see text]. In the presence of impaired renal function more accurate estimates of G.F.R. were obtained from the plasma creatinine and P.S.P. excretion tests (S.D. of estimate 8 and 13 ml./min. respectively). It was thought that these tests could well replace the commonly used blood urea nitrogen estimation as simple tests of renal function. PMID:14207792

Healy, J. K.; Edwards, K. D. G.; Whyte, H. M.

1964-01-01

31

Urinary phosphate\\/creatinine, calcium\\/creatinine, and magnesium\\/creatinine ratios in a healthy pediatric population  

Microsoft Academic Search

Objective: To determine reference values for urinary phosphate\\/creatinine (Cr) concentration ratios and to complete reference values for urinary calcium\\/creatinine and magnesium\\/creatinine ratios in the second morning urine sample of healthy infants, children, and adolescents.Design: Urinary P\\/Cr, Ca\\/Cr, and Mg\\/Cr ratios were determined from the second morning urine sample. Two urine samples were obtained 1 week apart from most subjects to

Vera Matos; Guy van Melle; Olivier Boulat; Michèle Markert; Claude Bachmann; Jean-Pierre Guignard

1997-01-01

32

Uric Acid and Hypertension: Cause or Effect?  

Microsoft Academic Search

Uric acid was first associated with primary hypertension in 1874, yet its role in this condition remains unclear. Historically,\\u000a uric acid was thought to be a secondary response to hypertension or its associated conditions. However, more recent experimental\\u000a and clinical studies suggest that uric acid could have a contributory role in the pathogenesis of elevated blood pressure.\\u000a More studies are

Marilda Mazzali; Mehmet Kanbay; Mark S. Segal; Mohamed Shafiu; Diana Jalal; Daniel I. Feig; Richard J. Johnson

2010-01-01

33

The molecular physiology of uric Acid homeostasis.  

PubMed

Uric acid, generated from the metabolism of purines, has proven and emerging roles in human disease. Serum uric acid is determined by production and the net balance of reabsorption or secretion by the kidney and intestine. A detailed understanding of epithelial absorption and secretion of uric acid has recently emerged, aided in particular by the results of genome-wide association studies of hyperuricemia. Novel genetic and regulatory networks with effects on uric acid homeostasis have also emerged. These developments promise to lead to a new understanding of the various diseases associated with hyperuricemia and to novel, targeted therapies for hyperuricemia. PMID:25422986

Mandal, Asim K; Mount, David B

2015-02-10

34

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

35

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

36

Discovery of an alternate metabolic pathway for urea synthesis in adult Aedes aegypti mosquitoes  

PubMed Central

We demonstrate the presence of an alternate metabolic pathway for urea synthesis in Aedes aegypti mosquitoes that converts uric acid to urea via an amphibian-like uricolytic pathway. For these studies, female mosquitoes were fed a sucrose solution containing 15NH4Cl, [5-15N]-glutamine, [15N]-proline, allantoin, or allantoic acid. At 24 h after feeding, the feces were collected and analyzed in a mass spectrometer. Specific enzyme inhibitors confirmed that mosquitoes incorporate 15N from 15NH4Cl into [5-15N]-glutamine and use the 15N of the amide group of glutamine to produce labeled uric acid. More importantly, we found that [15N2]-uric acid can be metabolized to [15N]-urea and be excreted as nitrogenous waste through an uricolytic pathway. Ae. aegypti express all three genes in this pathway, namely, urate oxidase, allantoinase, and allantoicase. The functional relevance of these genes in mosquitoes was shown by feeding allantoin or allantoic acid, which significantly increased unlabeled urea levels in the feces. Moreover, knockdown of urate oxidase expression by RNA interference demonstrated that this pathway is active in females fed blood or 15NH4Cl based on a significant increase in uric acid levels in whole-body extracts and a reduction in [15N]-urea excretion, respectively. These unexpected findings could lead to the development of metabolism-based strategies for mosquito control. PMID:18182492

Scaraffia, Patricia Y.; Tan, Guanhong; Isoe, Jun; Wysocki, Vicki H.; Wells, Michael A.; Miesfeld, Roger L.

2008-01-01

37

Discovery of an alternate metabolic pathway for urea synthesis in adult Aedes aegypti mosquitoes.  

PubMed

We demonstrate the presence of an alternate metabolic pathway for urea synthesis in Aedes aegypti mosquitoes that converts uric acid to urea via an amphibian-like uricolytic pathway. For these studies, female mosquitoes were fed a sucrose solution containing (15)NH4Cl, [5-(15)N]-glutamine, [(15)N]-proline, allantoin, or allantoic acid. At 24 h after feeding, the feces were collected and analyzed in a mass spectrometer. Specific enzyme inhibitors confirmed that mosquitoes incorporate (15)N from (15)NH4Cl into [5-(15)N]-glutamine and use the (15)N of the amide group of glutamine to produce labeled uric acid. More importantly, we found that [(15)N2]-uric acid can be metabolized to [(15)N]-urea and be excreted as nitrogenous waste through an uricolytic pathway. Ae. aegypti express all three genes in this pathway, namely, urate oxidase, allantoinase, and allantoicase. The functional relevance of these genes in mosquitoes was shown by feeding allantoin or allantoic acid, which significantly increased unlabeled urea levels in the feces. Moreover, knockdown of urate oxidase expression by RNA interference demonstrated that this pathway is active in females fed blood or (15)NH4Cl based on a significant increase in uric acid levels in whole-body extracts and a reduction in [(15)N]-urea excretion, respectively. These unexpected findings could lead to the development of metabolism-based strategies for mosquito control. PMID:18182492

Scaraffia, Patricia Y; Tan, Guanhong; Isoe, Jun; Wysocki, Vicki H; Wells, Michael A; Miesfeld, Roger L

2008-01-15

38

Creatinine clearance versus serum creatinine as a risk factor in cardiac surgery  

Microsoft Academic Search

BACKGROUND: Renal impairment is one of the predictors of mortality in cardiac surgery. Usually a binarized value of serum creatinine is used to assess the renal function in risk models. Creatinine clearance can be easily estimated by the Cockcroft and Gault equation from serum creatinine, gender, age and body weight. In this work we examine whether this estimation of the

Jörg Walter; Amir Mortasawi; Bert Arnrich; Alexander Albert; Inez Frerichs; Ulrich Rosendahl; Jürgen Ennker

2003-01-01

39

Decrease in Urinary Creatinine Excretion in Early Stage Chronic Kidney Disease  

PubMed Central

Background Little is known about muscle mass loss in early stage chronic kidney disease (CKD). We used 24-hour urinary creatinine excretion rate to assess determinants of muscle mass and its evolution with kidney function decline. We also described the range of urinary creatinine concentration in this population. Methods We included 1072 men and 537 women with non-dialysis CKD stages 1 to 5, all of them with repeated measurements of glomerular filtration rate (mGFR) by 51Cr-EDTA renal clearance and several nutritional markers. In those with stage 1 to 4 at baseline, we used a mixed model to study factors associated with urinary creatinine excretion rate and its change over time. Results Baseline mean urinary creatinine excretion decreased from 15.3±3.1 to 12.1±3.3 mmol/24 h (0.20±0.03 to 0.15±0.04 mmol/kg/24 h) in men, with mGFR falling from ?60 to <15 mL/min/1.73 m2, and from 9.6±1.9 to 7.6±2.5 (0.16±0.03 to 0.12±0.03) in women. In addition to mGFR, an older age, diabetes, and lower levels of body mass index, proteinuria, and protein intake assessed by urinary urea were associated with lower mean urinary creatinine excretion at baseline. Mean annual decline in mGFR was 1.53±0.12 mL/min/1.73 m2 per year and that of urinary creatinine excretion rate, 0.28±0.02 mmol/24 h per year. Patients with fast annual decline in mGFR of 5 mL/min/1.73 m2 had a decrease in urinary creatinine excretion more than twice as big as in those with stable mGFR, independent of changes in urinary urea as well as of other determinants of low muscle mass. Conclusions Decrease in 24-hour urinary creatinine excretion rate may appear early in CKD patients, and is greater the more mGFR declines independent of lowering protein intake assessed by 24-hour urinary urea. Normalizing urine analytes for creatininuria may overestimate their concentration in patients with reduced kidney function and low muscle mass. PMID:25401694

Tynkevich, Elena; Flamant, Martin; Haymann, Jean-Philippe; Metzger, Marie; Thervet, Eric; Boffa, Jean-Jacques; Vrtovsnik, François; Houillier, Pascal; Froissart, Marc; Stengel, Bénédicte

2014-01-01

40

Plasma Creatinine Clearance in the Dog  

ERIC Educational Resources Information Center

Lists materials and methods for an experiment that demonstrates the concept of glomerular filtration rate (GFR) using anesthesized dogs. In the dog, GFR is equivalent to the renal plasma clearance of exogenous creatinine. (CS)

Frazier, Loy W.

1977-01-01

41

Theobromine Inhibits Uric Acid Crystallization. A Potential Application in the Treatment of Uric Acid Nephrolithiasis  

PubMed Central

Purpose To assess the capacity of methylxanthines (caffeine, theophylline, theobromine and paraxanthine) to inhibit uric acid crystallization, and to evaluate their potential application in the treatment of uric acid nephrolithiasis. Materials and Methods The ability of methylxathines to inhibit uric acid nucleation was assayed turbidimetrically. Crystal morphology and its modification due to the effect of theobromine were evaluated by scanning electron microscopy (SEM). The ability of theobromine to inhibit uric acid crystal growth on calculi fragments resulting from extracorporeal shock wave lithotripsy (ESWL) was evaluated using a flow system. Results The turbidimetric assay showed that among the studied methylxanthines, theobromine could markedly inhibit uric acid nucleation. SEM images showed that the presence of theobromine resulted in thinner uric acid crystals. Furthermore, in a flow system theobromine blocked the regrowth of post-ESWL uric acid calculi fragments. Conclusions Theobromine, a natural dimethylxanthine present in high amounts in cocoa, acts as an inhibitor of nucleation and crystal growth of uric acid. Therefore, theobromine may be clinically useful in the treatment of uric acid nephrolithiasis. PMID:25333633

Grases, Felix; Rodriguez, Adrian; Costa-Bauza, Antonia

2014-01-01

42

Discovery of an alternate metabolic pathway for urea synthesis in adult Aedes aegypti mosquitoes  

E-print Network

fed a sucrose solution containing 15NH4Cl, [5-15N]-glutamine, [15N]-proline, allantoin, or allantoic, and allantoicase. The functional relevance of these genes in mosquitoes was shown by feeding allantoin or allantoic compounds. In some animals, uric acid can be converted to allantoin, allantoic acid, urea, and ammonia

Wysocki, Vicki H.

43

The cockroach Blattella germanica obtains nitrogen from uric acid through a metabolic pathway shared with its bacterial endosymbiont.  

PubMed

Uric acid stored in the fat body of cockroaches is a nitrogen reservoir mobilized in times of scarcity. The discovery of urease in Blattabacterium cuenoti, the primary endosymbiont of cockroaches, suggests that the endosymbiont may participate in cockroach nitrogen economy. However, bacterial urease may only be one piece in the entire nitrogen recycling process from insect uric acid. Thus, in addition to the uricolytic pathway to urea, there must be glutamine synthetase assimilating the released ammonia by the urease reaction to enable the stored nitrogen to be metabolically usable. None of the Blattabacterium genomes sequenced to date possess genes encoding for those enzymes. To test the host's contribution to the process, we have sequenced and analysed Blattella germanica transcriptomes from the fat body. We identified transcripts corresponding to all genes necessary for the synthesis of uric acid and its catabolism to urea, as well as for the synthesis of glutamine, asparagine, proline and glycine, i.e. the amino acids required by the endosymbiont. We also explored the changes in gene expression with different dietary protein levels. It appears that the ability to use uric acid as a nitrogen reservoir emerged in cockroaches after its age-old symbiotic association with bacteria. PMID:25079497

Patiño-Navarrete, Rafael; Piulachs, Maria-Dolors; Belles, Xavier; Moya, Andrés; Latorre, Amparo; Peretó, Juli

2014-07-01

44

Uric Acid, Hyperuricemia and Vascular Diseases  

PubMed Central

Uric acid is the product of purine metabolism. It is known that hyperuricemia, defined as high levels of blood uric acid, is the major etiological factor of gout. A number of epidemiological reports have increasingly linked hyperuricemia with cardiovascular and neurological diseases. Studies highlighting the pathogenic mechanisms of uric acid point to an inflammatory response as the primary mechanism for inducing gout and possibly contributing to uric acid's vascular effects. Monosodium urate (MSU) crystals induce an inflammatory reaction, which are recognized by Toll-like receptors (TLRs). These TLRs then activate NALP3 inflammasome. MSU also triggers neutrophil activation and further produces immune mediators, which lead to a proinflammatory response. In addition, soluble uric acid can also mediate the generation of free radicals and function as a pro-oxidant. This review summarizes the epidemiological studies of hyperuricemia and cardiovascular disease, takes a brief look at hyperuricemia and its role in neurological diseases, and highlights the studies of the advanced pathological mechanisms of uric acid and inflammation. PMID:22201767

Jin, Ming; Yang, Fan; Yang, Irene; Yin, Ying; Luo, Jin Jun; Wang, Hong; Yang, Xiao-Feng

2011-01-01

45

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

46

SOURCE ASSESSMENT: UREA MANUFACTURE  

EPA Science Inventory

The report gives results of an evaluation of the potential environmental effects of air emissions from the production of urea. Urea production in the U.S. was 3.45 million metric tons in 1975. Major products were urea solution (38%), granulated solid material (53%), and prilled s...

47

Association of uric acid, atherogenic index of plasma and albuminuria in diabetes mellitus  

PubMed Central

Background: The associations of serum uric acid (UA), atherogenic index of plasma (AIP) and albuminuria with cardiovascular disease have been shown. Several studies focused on association of serum UA and dyslipidemia, serum UA and renal impairment, dyslipidemia and renal impairment. However, to date, in literature, there have been no studies demonstrating the relationship between these parameters in diabetic patients together. Aims: We aimed to investigate the association between serum UA, albuminuria and AIP in diabetic patients. Methods: This was a retrospective study involving data of 645 diabetic patients. The patients were separated into groups according to their serum uric acid and AIP levels. The quantitative urine albumin/creatinine ratio in morning spot urine samples were used for standard albuminuria determination. Serum uric acid levels under 6 mg/dL were considered as normal. AIP was calculated as the logarithmically transformed ratio of triglyceride to high density lipoprotein cholesterol. Results: AIP and albuminuria levels were high in high serum UA group compared to normal UA group. Uric acid and albuminuria tended to increase with increasing AIP. Correlation analysis showed that albuminuria, AIP and UA were significantly correlated with each other. Additionally, in binary logistic regression analysis, AIP was found to be independently associated with high UA levels. Conclusions: Present study reveals that serum UA, AIP and albuminuria are closely related. Physicians should be aware that patients with concomitant hyperuricemia, albuminuria and high AIP are at increased risk of developing cardiovascular disease. Our study confirms that there is a need for larger prospective studies to determine the mechanisms underlying the association of serum UA, AIP and albuminuria. PMID:25664100

Akbas, Emin Murat; Timuroglu, Aysu; Ozcicek, Adalet; Ozcicek, Fatih; Demirtas, Levent; Gungor, Adem; Akbas, Nergis

2014-01-01

48

The Aerobic Breakdown of Uric Acid by Certain Pseudomonads  

Microsoft Academic Search

SUMMARY: Four pseudomonad isolates which could use uric acid aerobically as a sole C, N and energy source were isolated from poultry house deep-litter, droppings, and nearby soil. Organisms harvested from media containing uric acid can degrade uric acid completely, with the formation of CO, and NH,. Allantoin, allantoic, glyoxylic and formic acids were completely oxidized. The existence of micro-organisms

U. Bachrach

1957-01-01

49

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

50

Urea for hyponatremia?  

PubMed

Once the standard of care for cerebral edema, urea can also be used to treat hyponatremia. The 2014 European Clinical Practice Guidelines recommend urea for the treatment of the syndrome of inappropriate antidiuretic hormone, while discouraging use of vasopressin antagonists. Although there is evidence that urea can diminish hypertonic injury to brain cells caused by rapid correction of hyponatremia, clinical trials are needed that include patients at high risk to develop complications from overcorrection. PMID:25635717

Sterns, Richard H; Silver, Stephen M; Hix, John K

2015-02-01

51

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

52

Serum uric acid is inversely proportional to estimated stroke volume and cardiac output in a large sample of pharmacologically untreated subjects: data from the Brisighella Heart Study.  

PubMed

Serum uric acid is representative for xanthine-oxidase, the key enzyme involved in the production of uric acid, which is up-regulated in the failing heart, and may play an important role in the pathophysiologic process that leads to heart failure. In our study, we investigated the relation between stroke volume, cardiac output and serum uric acid in a large sample of overall healthy pharmacologically untreated subjects. The Brisighella Heart Study included 2,939 men and women between the ages of 14-84 without prior coronary heart disease or cerebrovascular disease who were not taking antihypertensive therapy at baseline. For this study, we selected 734 adult subjects enrolled in the last Brisighella population survey not taking antihypertensive, antidiabetic, lipid-lowering and uric acid-lowering drugs, and who were also not affected by chronic heart failure or by gout. The main predictors of cardiac functionality parameters were mean arterial pressure (MAP), HR, SUA and age (all p < 0.001), while gender, BMI, LDL-cholesterol, HDL-cholesterol, triglycerides, fasting plasma glucose, creatinine, estimated glomerular filtration rate, physical activity and smoking habit were not significantly associated (all p > 0.05). In particular, there is a strong relation between estimated cardiac output and serum uric acid (B = -0.219, p < 0.001) and between stroke volume and serum uric acid (B = -3.684, p < 0.001). These observations might have an impact on future considerations about serum uric acid as an early inexpensive marker of heart function decline in the general population. PMID:24214336

Cicero, Arrigo Francesco Giuseppe; Rosticci, Martina; Parini, Angelo; Baronio, Cristina; D'Addato, Sergio; Borghi, Claudio

2014-09-01

53

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. PMID:25050113

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

2014-01-01

54

Compact optical microfluidic uric acid analysis system  

Microsoft Academic Search

We designed, fabricated and tested a novel compact fluorescence analysis system for quantification of uric acid (UA) in clinical samples at the point-of-care. To perform an analysis, diluted saliva, urine or blood samples are simply placed in a disposable thin-film sample holder using a dropper. A new enzyme immobilization technique was developed to retain within the sample holder two enzymes

Chia-Pin Chang; David J. Nagel; Manuel T. Velasquez; Mona E. Zaghloul

2011-01-01

55

Role of insulin resistance in uric acid nephrolithiasis  

PubMed Central

Metabolic syndrome has been implicated in the pathogenesis of uric acid stones. Although not completely understood, its role is supported by many studies demonstrating increased prevalence of uric acid stones in patients with metabolic syndrome and in particular insulin resistance, a major component of metabolic syndrome. This review presents epidemiologic studies demonstrating the association between metabolic syndrome and nephrolithiasis in general as well as the relationship between insulin resistance and uric acid stone formation, in particular. We also review studies that explore the pathophysiologic relationship between insulin resistance and uric acid nephrolithiasis. PMID:25374817

Li, Hanhan; Klett, Dane E; Littleton, Raymond; Elder, Jack S; Sammon, Jesse D

2014-01-01

56

Phenindione interference in enzymatic creatinine assay - A case report.  

PubMed

Enzymatic creatinine assays are considered superior to Jaffe assays due to greater analytical specificity. We report a case of phenindione interference with an enzymatic assay resulting in significant misclassification in a patient with chronic kidney disease (CKD). Analysis of creatinine values of a further 36 patients who were treated with phenindione showed significant negative interference of phenindione with the Roche enzymatic creatinine assay. PMID:24361058

Natarajan, Balan; Hart, Tanya; Smith, Sophy; Parry, Robin Geoffrey

2015-02-01

57

21 CFR 862.1225 - Creatinine test system.  

Code of Federal Regulations, 2014 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....

2014-04-01

58

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. PMID:17581641

Peake, *Michael; Whiting, Malcolm

2006-01-01

59

Nasal secretion of the ozone scavenger uric acid  

SciTech Connect

Uric acid, an important scavenger of ozone, has been identified as the major low molecular weight antioxidant in baseline and cholinergically induced nasal secretions. The purpose of this study was to determine the specific tissue source of uric acid in airway secretions. The secretion of uric acid is increased by cholinergic stimulation and correlates closely with the secretion of lactoferrin (a nasal glandular protein), suggesting that submucosal glands are involved. Indeed, nasal turbinate tissue was found to contain uric acid. However, careful analysis of nasal turbinate tissue failed to reveal the presence of xanthine oxidase, the enzyme responsible for uric acid synthesis. These data suggest that uric acid might be taken up secondarily by glands from plasma. This possibility was strengthened by the observation that lowering the plasma urate level with probenecid concomitantly lowered urate secretion. These findings are consistent with the hypotheses that the principal source of uric acid in nasal secretions is plasma and that uric acid is taken up, concentrated, and secreted by nasal glands.

Peden, D.B.; Swiersz, M.; Ohkubo, K.; Hahn, B.; Emery, B.; Kaliner, M.A. (Univ. of North Carolina, Chapel Hill (United States))

1993-08-01

60

Ancient insights into uric acid metabolism in primates  

E-print Network

such as gout and hypertension have plagued us for centu- ries. The prevalence of gout in the United States has, a key enzyme that metabolizes uric acid, leaving us vulnerable to diseases such as gout rise to the well-known joint pain associated with gout. Elevated uric acid levels have also been

Chang, Belinda

61

A Potentiometric Indirect Uric Acid Sensor Based on ZnO Nanoflakes and Immobilized Uricase  

PubMed Central

In the present work zinc oxide nanoflakes (ZnO-NF) structures with a wall thickness around 50 to 100 nm were synthesized on a gold coated glass substrate using a low temperature hydrothermal method. The enzyme uricase was electrostatically immobilized in conjunction with Nafion membrane on the surface of well oriented ZnO-NFs, resulting in a sensitive, selective, stable and reproducible uric acid sensor. The electrochemical response of the ZnO-NF-based sensor vs. a Ag/AgCl reference electrode was found to be linear over a relatively wide logarithmic concentration range (500 nM to 1.5 mM). In addition, the ZnO-NF structures demonstrate vast surface area that allow high enzyme loading which results provided a higher sensitivity. The proposed ZnO-NF array-based sensor exhibited a high sensitivity of ?66 mV/ decade in test electrolyte solutions of uric acid, with fast response time. The sensor response was unaffected by normal concentrations of common interferents such as ascorbic acid, glucose, and urea. PMID:22736977

Usman Ali, Syed M.; Ibupoto, Zafar Hussain; Kashif, Muhammad; Hashim, Uda; Willander, Magnus

2012-01-01

62

Linking uric acid metabolism to diabetic complications  

PubMed Central

Hyperuricemia have been thought to be caused by the ingestion of large amounts of purines, and prevention or treatment of hyperuricemia has intended to prevent gout. Xanthine dehydrogenase/xanthine oxidase (XDH/XO) is rate-limiting enzyme of uric acid generation, and allopurinol was developed as a uric acid (UA) generation inhibitor in the 1950s and has been routinely used for gout prevention since then. Serum UA levels are an important risk factor of disease progression for various diseases, including those related to lifestyle. Recently, other UA generation inhibitors such as febuxostat and topiroxostat were launched. The emergence of these novel medications has promoted new research in the field. Lifestyle-related diseases, such as metabolic syndrome or type 2 diabetes mellitus, often have a common pathological foundation. As such, hyperuricemia is often present among these patients. Many in vitro and animal studies have implicated inflammation and oxidative stress in UA metabolism and vascular injury because XDH/XO act as one of the major source of reactive oxygen species Many studies on UA levels and associated diseases implicate involvement of UA generation in disease onset and/or progression. Interventional studies for UA generation, not UA excretion revealed XDH/XO can be the therapeutic target for vascular injury and renal dysfunction. In this review, the relationship between UA metabolism and diabetic complications is highlighted. PMID:25512781

Kushiyama, Akifumi; Tanaka, Kentaro; Hara, Shigeko; Kawazu, Shoji

2014-01-01

63

Linking uric acid metabolism to diabetic complications.  

PubMed

Hyperuricemia have been thought to be caused by the ingestion of large amounts of purines, and prevention or treatment of hyperuricemia has intended to prevent gout. Xanthine dehydrogenase/xanthine oxidase (XDH/XO) is rate-limiting enzyme of uric acid generation, and allopurinol was developed as a uric acid (UA) generation inhibitor in the 1950s and has been routinely used for gout prevention since then. Serum UA levels are an important risk factor of disease progression for various diseases, including those related to lifestyle. Recently, other UA generation inhibitors such as febuxostat and topiroxostat were launched. The emergence of these novel medications has promoted new research in the field. Lifestyle-related diseases, such as metabolic syndrome or type 2 diabetes mellitus, often have a common pathological foundation. As such, hyperuricemia is often present among these patients. Many in vitro and animal studies have implicated inflammation and oxidative stress in UA metabolism and vascular injury because XDH/XO act as one of the major source of reactive oxygen species Many studies on UA levels and associated diseases implicate involvement of UA generation in disease onset and/or progression. Interventional studies for UA generation, not UA excretion revealed XDH/XO can be the therapeutic target for vascular injury and renal dysfunction. In this review, the relationship between UA metabolism and diabetic complications is highlighted. PMID:25512781

Kushiyama, Akifumi; Tanaka, Kentaro; Hara, Shigeko; Kawazu, Shoji

2014-12-15

64

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)

1997-01-01

65

A General Photonic Crystal Sensing Motif: Creatinine in Bodily Fluids  

E-print Network

is rapidly hydrolyzed by the CD enzyme in a reaction which releases OH- . This elevates the steady-state pH relevant creatinine levels, with a detection limit of 6 µM, at physiological pH and salinity. This sensor also determines physiological levels of creatinine in human blood serum samples. This sensing

Asher, Sanford A.

66

Separation methods applicable to urinary creatine and creatinine  

Microsoft Academic Search

Urinary creatinine has been analyzed for many years as an indicator of glomerular filtration rate. More recently, interest in studying the uptake of creatine as a result of creatine supplementation, a practice increasingly common among bodybuilders and athletes, has lead to a need to measure urinary creatine concentrations. Creatine levels are of the same order of magnitude as creatinine levels

Truis Smith-Palmer

2002-01-01

67

Molecular evolution of urea amidolyase and urea carboxylase in fungi  

PubMed Central

Background Urea amidolyase breaks down urea into ammonia and carbon dioxide in a two-step process, while another enzyme, urease, does this in a one step-process. Urea amidolyase has been found only in some fungal species among eukaryotes. It contains two major domains: the amidase and urea carboxylase domains. A shorter form of urea amidolyase is known as urea carboxylase and has no amidase domain. Eukaryotic urea carboxylase has been found only in several fungal species and green algae. In order to elucidate the evolutionary origin of urea amidolyase and urea carboxylase, we studied the distribution of urea amidolyase, urea carboxylase, as well as other proteins including urease, across kingdoms. Results Among the 64 fungal species we examined, only those in two Ascomycota classes (Sordariomycetes and Saccharomycetes) had the urea amidolyase sequences. Urea carboxylase was found in many but not all of the species in the phylum Basidiomycota and in the subphylum Pezizomycotina (phylum Ascomycota). It was completely absent from the class Saccharomycetes (phylum Ascomycota; subphylum Saccharomycotina). Four Sordariomycetes species we examined had both the urea carboxylase and the urea amidolyase sequences. Phylogenetic analysis showed that these two enzymes appeared to have gone through independent evolution since their bacterial origin. The amidase domain and the urea carboxylase domain sequences from fungal urea amidolyases clustered strongly together with the amidase and urea carboxylase sequences, respectively, from a small number of beta- and gammaproteobacteria. On the other hand, fungal urea carboxylase proteins clustered together with another copy of urea carboxylases distributed broadly among bacteria. The urease proteins were found in all the fungal species examined except for those of the subphylum Saccharomycotina. Conclusions We conclude that the urea amidolyase genes currently found only in fungi are the results of a horizontal gene transfer event from beta-, gamma-, or related species of proteobacteria. The event took place before the divergence of the subphyla Pezizomycotina and Saccharomycotina but after the divergence of the subphylum Taphrinomycotina. Urea carboxylase genes currently found in fungi and other limited organisms were also likely derived from another ancestral gene in bacteria. Our study presented another important example showing plastic and opportunistic genome evolution in bacteria and fungi and their evolutionary interplay. PMID:21447149

2011-01-01

68

Amniotic fluid bilirubin and creatinine concentrations in Nigerian pregnant women.  

PubMed

Amniotic fluid bilirubin and creatinine levels were determined in 143 pregnant patients of known maturity. The bilirubin values did not bear any significant relationship with the gestational age. The creatinine levels however, showed a rise as pregnancy progressed. Amiotic fluid mean creatinine values were below 1 mg/100 ml before 30 weeks and around 2 mg/100 ml close to term. Eighty per cent of all creatinine values at 37 weeks gestation and over were 1.6 mg/100 ml or more. The mean level of creatinine in amniotic fluid correlated with gestational age. This test can therefore be applied antenatally along with other clinical data to distinguish between the premature and mature infants. PMID:16296133

Ogunbode, T; Ayeni, O; Adadevoh, B K

1976-04-01

69

Evidence for urea cycle activity in Sporosarcina ureae  

Microsoft Academic Search

Sporosarcina ureae BS 860, a motile, sporeforming coccus, possesses the enzymes required for a functioning urea (ornithine) cycle. This is only the second known example of urea cycle activity in a prokaryote. Specific activities are reported for ornithine carbamoyltransferase, argininosuccinase, arginase, and urease. Although argininosuccinate synthetase activity could not be detected directly in crude cell extracts, indirect evidence from radiocarbon

Stephen E. Gruninger; Manuel Goldman

1988-01-01

70

Uric acid is a risk factor for ischemic stroke and all-cause mortality in the general population: a gender specific analysis from The Tromsø 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. PMID:24330812

2013-01-01

71

21 CFR 862.1775 - Uric acid test system.  

Code of Federal Regulations, 2012 CFR

...DRUG 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. A...

2012-04-01

72

21 CFR 862.1225 - Creatinine test system.  

Code of Federal Regulations, 2012 CFR

...DRUG 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. A...

2012-04-01

73

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

74

Urine Creatinine Excretion and Clinical Outcomes in CKD  

PubMed Central

Summary Background and objectives Twenty-four–hour urine creatinine excretion is a reliable approximation of muscle mass. Whether changes in urine creatinine predict clinical outcomes in persons with CKD is unknown. This work studied the relationship between urine creatinine and patient and renal survival in people with CKD not requiring renal replacement therapy. Design, setting, participants, & measurements This longitudinal cohort study included incident stages 3–5 CKD patients referred to the renal clinic at the University Federico II in Naples between January of 1995 and December of 2005. Clinical data and urine creatinine were updated at each visit. Main outcomes were all-cause mortality and kidney failure requiring dialysis. Results This study enrolled 525 individuals and followed them for a median of 6 years (range of 4 months to 15 years). Urine creatinine excretion declined by 16 mg/d per year (95% confidence interval, 14 to 19) in participants with CKD stages 3a, 3b, and 4, and it remained stable in participants with stage 5 CKD. Per each 20 mg/d decline in urine creatinine, mortality increased by 3% (adjusted hazard ratio, 1.03; 95% confidence interval, 1.01 to 1.05), and the risk of initiating dialysis increased by 2% (adjusted hazard ratio, 1.02; 95% confidence interval, 1.01 to 1.03). These associations were independent of body mass index and GFR. Conclusions In persons with CKD stages 3 and 4, urine creatinine declines at a rate of 16 mg/d per year. Lower urine creatinine excretion predicts greater risk of kidney failure and patient mortality. PMID:24158796

Di Micco, Lucia; Quinn, Robert Ross; Ronksley, Paul Everett; Bellizzi, Vincenzo; Lewin, Adriane Marlene; Cianciaruso, Bruno

2013-01-01

75

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

76

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

77

Original article Partition of nitrogenous substances in the urine  

E-print Network

and urea, allantoin, free amino acids, uric acid, hippuric acid, creatinine, creatine and ammo- nia were% during low dietary protein intakes and allantoin excretion increases in such a way that allantoin may

Paris-Sud XI, Université de

78

[Tables estimating glomerular filtration rate from plasma creatinine].  

PubMed

Chronic kidney disease (CKD) and its related complications have become an important health and social problem. Very expensive resources are required in end-stage renal disease, and both complications of CKD as well as the important associated cardiovascular risk demand for interventions long before renal substitution therapies are needed. Thus, early diagnosis of CKD is currently considered of paramount importance, and it is based essentially upon the estimation of the glomerular filtration rate by formulae such as the abbreviated equation of the MDRD study. Nevertheless, in spite of international published recommendations, an automatic calculation to estimate the glomerular filtration rate (GFR) from serum creatinine is not reported by most laboratories yet and the need for creatinine assay standardisation is far from being implemented. Thus, we have designed some tables to show the creatinine value corresponding to different GFR for ages between 20 and 90 y/o, at 5 years intervals and in both sexes with both the MDRD-4 and MDRD-IDMS equations (Modification of Diet in Renal Disease-Isotope Dilution Mass Spectrometry). Moreover, we have created a global table including an estimation of GFR from plasma creatinine, age and sex by the MDRD-IDMS formula, the recommended for those laboratories which measure serum creatinine with assays aligned to the reference method. These tables aim to increase the awareness of the different assays for serum creatinine and to facilitate the diagnosis of CKD converting serum creatinine into GFR. This action should allow not only the early detection but also the possibility to establish the appropriate medical actions recommended after CKD detection. PMID:18590499

Canal, C; Pellicer, R; Rocha, C I; Calero, F; Gracia, S; Montañés, R; Ballarín, J; Bover, J

2008-01-01

79

Calibrationless determination of creatinine and ammonia by coulometric flow titration.  

PubMed

A precise and sensitive working microflow titration procedure was developed to determine creatinine and ammonia in urine samples. This procedure is based on enzymatic conversion of creatinine, gas diffusional membrane separation of the released ammonia into an acid acceptor stream, and coulometric titration of ammonia with hypobromite. The hypobromite is formed after the electrogeneration of bromine in an electrolyte containing 1.0 M NaBr and 0.1 M sodium borate adjusted to pH 8.5. The electrolysis current follows a triangle-programmed current-time course. An amperometric flow detector records the resulting mirror symmetrical titration curves, which show two equivalence points. The analyte concentration is calculated from the time difference between the equivalence points. For quantitative conversion of creatinine and quantitative separation of present and released ammonia no calibration is necessary to get accurate results. Both ammonia/ammonium and creatinine were determined in the range between 2 microM and 2 mM with relative standard deviations between 3.0 and 1.0% (n = 5). High recoveries were obtained for the analysis of diluted urine samples for both creatinine and ammonia. PMID:10906237

He, Z K; Fuhrmann, B; Spohn, U

2000-08-01

80

Epidemiology and clinical pathophysiology of uric acid kidney stones.  

PubMed

There is global diversity in the prevalence of uric acid (UA) nephrolithiasis. UA nephrolithiasis comprises 8-10 % of all kidney stones in the United States. However, its prevalence is higher in patients with type 2 diabetes mellitus and those with obesity. Three significant urinary abnormalities have been described as the main etiologic factors for the development of UA nephrolithiasis; low urinary pH, hyperuricosuria and low urinary volume. However, an unduly acidic urine below the ionization constant of uric acid (pKa < 5.5) increases the urinary content of undissociated uric acid and thereby uric acid precipitation. Previous studies have shown the two major pathogenic mechanisms for unduly urinary pH are increased net acid excretion (NAE) and reduced renal ammonium (NH4 (+)), with a combination resulting in overly acidic urine. The impaired ammonium excretion has been demonstrated in a steady state in 24-hour urine and also following an oral ammonium chloride (NH4Cl) challenge to amplify ammoniogenic defects in this population. Similar abnormalities have been disclosed in normal populations and also in T2DM populations without kidney stones. To date, the underlying mechanism of increased acid production, source and nature of putative organic acid anions have not been fully elucidated. One plausible mechanism is the production of organic acid by intestinal and aerobic metabolism. This may occur in obese, diabetic and uric acid stone formers due to the differences in gut microflora. PMID:24497296

Sakhaee, Khashayar

2014-06-01

81

Uric Acid Nephrolithiasis: Recent Progress and Future Directions  

PubMed Central

The prevalence of urolithiasis has been increasing for the past few decades in industrialized nations. Uric acid calculi account for a significant percentage of urinary stones. Certain risk factors may be involved in the pathogenesis of uric acid nephrolithiasis, including hyperuricosuria, low urinary volume, and persistently low urinary pH. Patients with medical conditions that promote profound hyperuricosuria are at high risk of developing uric acid calculi. These conditions include chronic diarrheal states; myeloproliferative disorders; insulin resistance, including diabetes mellitus; and monogenic metabolic disorders, such as Lesch-Nyhan syndrome. Computed tomography can provide a definitive diagnosis. Except in cases in which there is severe obstruction, progressive azotemia, serious infection, or unremitting pain, the initial treatment of patients with uric acid nephrolithiasis should be medical dissolution therapy because this approach is successful in the majority of cases. A thorough review of the epidemiology and pathophysiology of uric acid nephrolithiasis is crucial for the diagnosis, treatment, and prevention of stones in patients with this condition. PMID:17396168

Ngo, Tin C; Assimos, Dean G

2007-01-01

82

Utility of endogenous creatinine clearance as a measure of renal function in mice  

Microsoft Academic Search

Utility of endogenous creatinine clearance as a measure of renal function in mice.BackgroundThe use of endogenous plasma creatinine levels and creatinine clearance as a tool to evaluate renal function in mice has come under scrutiny as prior studies have reported that the Jaffé alkaline picrate method grossly overestimates true plasma creatinine in mice. As members of the NIDDK Animal Models

Stephen R. Dunn; Zhonghua Qi; Erwin P. Bottinger; Matthew D. Breyer; Kumar Sharma

2004-01-01

83

MANAGING UREA-CONTAINING FERTILIZERS  

E-print Network

-- 83 Urea 16 122 UAN solution (28%) 12 125 Ammonium nitrate 2 132 Oberle & Bundy, 1988. Data from one, Lancaster, WI N source Ammonia loss (%) Yield (tons/acre) None -- 0.74 Urea 19 1.09 Ammonium nitrate 1 1 1993 1994 1995 ----------- bu/acre --------- Ammonium nitrate 118 a 177 a 163 a UAN spray 94 bc 140 b

Balser, Teri C.

84

Phylogenetic Status of Sporosarcina ureae  

Microsoft Academic Search

The taxonomic position of Sporosarcina ureae has been historically controversial: in the seventh edition of Bergey's Manual (21, it is as- signed to the genus Sarcina in the family Mi- crococcaceae, whereas in the most recent edi- tion it is placed in the family Bacillaceae (3). The controversy originates from the fact that the vegetative cells of S. ureae resemble

KENNETH J. PECHMAN; BOBBY J. LEWIS; CARL R. WOESE

85

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. PMID:24511458

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

2014-01-01

86

Serum creatinine and prostate cancer risk in a prospective study  

PubMed Central

Background Several studies have examined serum creatinine as a marker for prostate cancer stage, recurrence, and prognosis. We evaluated whether serum creatinine concentration was associated with risk of developing prostate cancer in a prospective cohort of male smokers. Methods A nested case-control study within the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study of 50–69 year old Finnish men was conducted. Two controls (n=464) were matched to each case (n=232) on study center, intervention group, date of baseline blood draw (±45 days), and age (±5 years). Conditional logistic regression was used to calculate odds ratios (OR) and 95% confidence intervals (CI). All p-values were two-sided. Results Cases had significantly higher pre-diagnostic serum creatinine concentrations compared with controls (medians of 1.13 vs 1.10 mg/dL, respectively; p=0.004). Serum creatinine was associated with a significantly greater risk of prostate cancer (multivariate OR=2.23, 95% CI 1.33–3.75 for highest vs. lowest quartile), with a significant trend (p-trend = 0.0008). Exclusion of subjects with a reported history of diabetes, benign prostatic hyperplasia, or hypertension, or whose cancer was diagnosed within the first five years of follow-up, did not alter the association. Risk did not differ by disease stage or time from blood draw to diagnosis. Conclusion Prospectively measured serum creatinine, within normal ranges, is positively related to prostate cancer risk. Future research should reexamine the association in other populations, including any inter-relationship with serum prostate-specific antigen. PMID:19755655

Weinstein, Stephanie J.; Mackrain, Katrina; Stolzenberg-Solomon, Rachael Z.; Selhub, Jacob; Virtamo, Jarmo; Albanes, Demetrius

2009-01-01

87

Serum uric acid level, blood pressure, and vascular angiotensin II responsiveness in healthy men and women.  

PubMed

Uric acid is associated with hypertension and increased renin-angiotensin system activity, although this relationship diminishes after chronic exposure to high levels. Uric acid is more strongly associated with poor outcomes in women compared to men, although whether this is due to a sex-specific uric acid-mediated pathophysiology or reflects sex differences in baseline uric acid levels remains unknown. We examined the association between uric acid and vascular measures at baseline and in response to angiotensin-II challenge in young healthy humans. Fifty-two subjects (17 men, 35 premenopausal women) were studied in high-salt balance. Serum uric acid levels were significantly higher in men compared to women (328 ± 14 ?mol/L vs. 248 ± 10 ?mol/L, P < 0.001), although all values were within normal sex-specific range. Men demonstrated no association between uric acid and blood pressure, either at baseline or in response to angiotensin-II. In stark contrast, a significant association was observed between uric acid and blood pressure at baseline (systolic blood pressure, P = 0.005; diastolic blood pressure, P = 0.02) and in response to angiotensin-II (systolic blood pressure, P = 0.035; diastolic blood pressure, P = 0.056) in women. However, this sex difference lost significance after adjustment for baseline uric acid. When all subjects were stratified according to high (>300 ?mol/L) or low (?300 ?mol/L) uric acid levels, only the low uric acid group showed a positive association between uric acid and measures of vascular tone at baseline and in response to angiotensin-II. Differences in uric acid-mediated outcomes between men and women likely reflect differences in exposure to increased uric acid levels, rather than a sex-specific uric acid-mediated pathophysiology. PMID:25501427

Samimi, Arian; Ramesh, Sharanya; Turin, Tanvir C; MacRae, Jennifer M; Sarna, Magdalena A; Reimer, Raylene A; Hemmelgarn, Brenda R; Sola, Darlene Y; Ahmed, Sofia B

2014-12-01

88

Acute obstructive uric acid nephropathy after treatment of neoplastic adenopathy.  

PubMed

Patients with lymphoma and leukemia are at increased risk of therapy-related sudden increase in the serum uric acid level, with resultant precipitation and obstruction in the more acidic and concentrated distal nephron. Appropriate pretreatment measures can prevent intrarenal crystal formation. The acute obstruction responds well to treatment, and aggressive measures are indicated. PMID:7221659

Fitzgerald, R H; Wallace, K M; Baker, A S

1981-04-01

89

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.

90

Influence of ascorbic acid on BUN, creatinine, resistive index in canine renal ischemia-reperfusion injury.  

PubMed

Renal ischemia as a course of renal transplantation is a common cause of renal dysfunction as renal failure. The purpose of this study was to investigate the influence of ascorbic acid on blood urea nitrogen (BUN), creatinine (Cr) and resistive index (RI) for dog models with renal ischemia-reperfusion (I/R) injury. Renal ischemia was induced on 6 Beagle dogs. The left kidney was exposed to normothermic ischemia for a short period at 30 min followed by reperfusion. On the blood Cr level and RI, there was no significant difference comparing both groups. 14 days after I/R injury a significant reduction on the blood BUN level was observed in the vehicle group (34.06 mg/dl) compared to that of ischemia induced treated group (10.3 mg/dl) (p < 0.05). In conclusion, administration of ascorbic acid for renal ischemic-reperfusion injury had influence on blood BUN level, but it was not revealed the influence on blood Cr and RI. PMID:16434855

Lee, Jae-il; Kim, Myung-jin; Park, Chang-sik; Kim, Myung-cheol

2006-03-01

91

AC OMPARISON OF URIC ACID LEVELS IN BLACK AFRICAN VS CAUCASIAN WOMEN FROM SOUTH AFRICA: THE POWIRS STUDY  

Microsoft Academic Search

Objectives: Elevated levels of uric acid are often associated with cardiometabolic risk factors. The aim of this study was to determine whether uric acid levels differ between African and Caucasian women and whether uric acid is associated with cardiometabolic risk factors within the two ethnic groups. Methods: Women from African (N5102) and Caucasian (N5115) descent were recruited and their uric

I. M. Palmer; A. E. Schutte; H. W. Huisman; J. M. Van Rooyen; R. Schutte; L. Malan; N. T. Malan

92

Urea biosensor for hemodialysis monitoring  

Microsoft Academic Search

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

1999-01-01

93

Urea biosensor for hemodialysis monitoring  

Microsoft Academic Search

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

Robert S

1999-01-01

94

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

95

Contribution of the organic anion transporter OAT2 to the renal active tubular secretion of creatinine and mechanism for serum creatinine elevations caused by cobicistat.  

PubMed

Many xenobiotics including the pharmacoenhancer cobicistat increase serum creatinine by inhibiting its renal active tubular secretion without affecting the glomerular filtration rate. This study aimed to define the transporters involved in creatinine secretion, applying that knowledge to establish the mechanism for xenobiotic-induced effects. The basolateral uptake transporters organic anion transporter OAT2 and organic cation transporters OCT2 and OCT3 were found to transport creatinine. At physiologic creatinine concentrations, the specific activity of OAT2 transport was over twofold higher than OCT2 or OCT3, establishing OAT2 as a likely relevant creatinine transporter and further challenging the traditional view that creatinine is solely transported by a cationic pathway. The apical multidrug and toxin extrusion transporters MATE1 and MATE2-K demonstrated low-affinity and high-capacity transport. All drugs known to affect creatinine inhibited OCT2 and MATE1. Similar to cimetidine and ritonavir, cobicistat had the greatest effect on MATE1 with a 50% inhibition constant of 0.99??M for creatinine transport. Trimethoprim potently inhibited MATE2-K, whereas dolutegravir preferentially inhibited OCT2. Cimetidine was unique, inhibiting all transporters that interact with creatinine. Thus, the clinical observation of elevated serum creatinine in patients taking cobicistat is likely a result of OCT2 transport, facilitating intracellular accumulation, and MATE1 inhibition. PMID:24646860

Lepist, Eve-Irene; Zhang, Xuexiang; Hao, Jia; Huang, Jane; Kosaka, Alan; Birkus, Gabriel; Murray, Bernard P; Bannister, Roy; Cihlar, Tomas; Huang, Yong; Ray, Adrian S

2014-08-01

96

Contribution of the organic anion transporter OAT2 to the renal active tubular secretion of creatinine and mechanism for serum creatinine elevations caused by cobicistat  

PubMed Central

Many xenobiotics including the pharmacoenhancer cobicistat increase serum creatinine by inhibiting its renal active tubular secretion without affecting the glomerular filtration rate. This study aimed to define the transporters involved in creatinine secretion, applying that knowledge to establish the mechanism for xenobiotic-induced effects. The basolateral uptake transporters organic anion transporter OAT2 and organic cation transporters OCT2 and OCT3 were found to transport creatinine. At physiologic creatinine concentrations, the specific activity of OAT2 transport was over twofold higher than OCT2 or OCT3, establishing OAT2 as a likely relevant creatinine transporter and further challenging the traditional view that creatinine is solely transported by a cationic pathway. The apical multidrug and toxin extrusion transporters MATE1 and MATE2-K demonstrated low-affinity and high-capacity transport. All drugs known to affect creatinine inhibited OCT2 and MATE1. Similar to cimetidine and ritonavir, cobicistat had the greatest effect on MATE1 with a 50% inhibition constant of 0.99??M for creatinine transport. Trimethoprim potently inhibited MATE2-K, whereas dolutegravir preferentially inhibited OCT2. Cimetidine was unique, inhibiting all transporters that interact with creatinine. Thus, the clinical observation of elevated serum creatinine in patients taking cobicistat is likely a result of OCT2 transport, facilitating intracellular accumulation, and MATE1 inhibition. PMID:24646860

Lepist, Eve-Irene; Zhang, Xuexiang; Hao, Jia; Huang, Jane; Kosaka, Alan; Birkus, Gabriel; Murray, Bernard P; Bannister, Roy; Cihlar, Tomas; Huang, Yong; Ray, Adrian S

2014-01-01

97

Estimation of glomerular filtration rate from serum creatinine and cystatin C in octogenarians and nonagenarians  

PubMed Central

Background Equations to estimate GFR have not been well validated in the elderly and may misclassify persons with chronic kidney disease (CKD). We measured GFR and compared the performance of the Modification of Diet in Renal Disease (MDRD), the Chronic Kidney Disease-Epidemiology Collaboration (CKD-Epi) and the Berlin Initiative Study (BIS) equations based on creatinine and/or cystatin C in octogenarians and nonagenarians. Methods Using cross-sectional analysis we assessed 95 very elderly persons (mean 85 years) living in the community. GFR was measured by iohexol (mGFR) and compared with estimates using six equations: MDRD, CKD-Epi_creatinine, CKD-Epi_cystatin, CKD-Epi_creatinine-cystatin, BIS_creatinine and BIS_creatinine-cystatin. Results Mean mGFR was 55 (range,19–86) ml/min/1.73 m2. Bias was smaller with the CKD-Epi_creatinine-cystatin and the CKD-Epi_creatinine equations (-4.0 and 1.7 ml/min/1.73 m2). Accuracy (percentage of estimates within 30% of mGFR) was greater with the CKD-Epi_creatinine-cystatin, BIS_creatinine-cystatin and BIS_creatinine equations (85%, 83% and 80%, respectively). Among the creatinine-based equations, the BIS_creatinine had the greatest accuracy at mGFR?creatinine was superior at higher GFRs (79% and 90%, respectively). The CKD-Epi_creatinine-cystatin, BIS_creatinine-cystatin and CKD-Epi_cystatin equations yielded the greatest areas under the receiver operating characteristic curve at GFR threshold?=?60 ml/min/1.73 m2 (0.88, 0.88 and 0.87, respectively). In participants classified based on the BIS_creatinine, CKD-Epi_cystatin, or BIS_creatinine-cystatin equations, the CKD-Epi_creatinine-cystatin equation tended to improve CKD classification (net reclassification index: 12.7%, p?=?0.18; 6.7%, p?=?0.38; and 15.9%; p?=?0.08, respectively). Conclusions GFR-estimating equations CKD-Epi_creatinine-cystatin and BIS_creatinine-cystatin showed better accuracy than other equations using creatinine or cystatin C alone in very elderly persons. The CKD-Epi_creatinine-cystatin equation appears to be advantageous in CKD classification. If cystatin C is not available, both the BIS_cr equation and the CKD-Epi_cr equation could be used, although at mGFR?

2013-01-01

98

Crystal-matrix interrelations in brushite and uric acid calculi.  

PubMed

Brushite and uric acid calculi were studied by means of scanning electron microscopy with the partial dissolution method and transmission electron microscopy. Brushite calculi consist of radially oriented columnar crystals which have sheet-like substructure. The organic matrix is identified chiefly at the outside of the crystals but partly included between the substructure. The concentric matrix bands are often dislocated between the neighbouring crystals. Uric acid calculi also consist of radially oriented columnar crystals, and a fine meshwork of the organic matrix is incorporated within the crystals. The concentric matrix layers of different density are angled according to the crystal lattice. These findings indicate that the organic matrix arose from a mucinous surface coat, at least in the radially striated calculi. The crystals continued to grow in this gel-state milieu, either thrusting the matrix aside or incorporating it within the crystals. PMID:3944880

Iwata, H; Abe, Y; Nishio, S; Wakatsuki, A; Ochi, K; Takeuchi, M

1986-02-01

99

Effect of nutrition level and diets on creatinine excretion by sheep  

Microsoft Academic Search

In this experiment, creatinine (C) excretion by sheep was measured when they were fed different diets at different levels of intake. Creatinine excretion was not affected by the level of feed intake or the addition of salt to lucerne-based diets. However, differences between individual animals were significant. Creatinine excretion was significantly affected by diets, which were formulated by combining different

Z. J. Liu; N. P. McMeniman

2006-01-01

100

Sugar, uric acid, and the etiology of diabetes and obesity.  

PubMed

The intake of added sugars, such as from table sugar (sucrose) and high-fructose corn syrup has increased dramatically in the last hundred years and correlates closely with the rise in obesity, metabolic syndrome, and diabetes. Fructose is a major component of added sugars and is distinct from other sugars in its ability to cause intracellular ATP depletion, nucleotide turnover, and the generation of uric acid. In this article, we revisit the hypothesis that it is this unique aspect of fructose metabolism that accounts for why fructose intake increases the risk for metabolic syndrome. Recent studies show that fructose-induced uric acid generation causes mitochondrial oxidative stress that stimulates fat accumulation independent of excessive caloric intake. These studies challenge the long-standing dogma that "a calorie is just a calorie" and suggest that the metabolic effects of food may matter as much as its energy content. The discovery that fructose-mediated generation of uric acid may have a causal role in diabetes and obesity provides new insights into pathogenesis and therapies for this important disease. PMID:24065788

Johnson, Richard J; Nakagawa, Takahiko; Sanchez-Lozada, L Gabriela; Shafiu, Mohamed; Sundaram, Shikha; Le, Myphuong; Ishimoto, Takuji; Sautin, Yuri Y; Lanaspa, Miguel A

2013-10-01

101

Sugar, Uric Acid, and the Etiology of Diabetes and Obesity  

PubMed Central

The intake of added sugars, such as from table sugar (sucrose) and high-fructose corn syrup has increased dramatically in the last hundred years and correlates closely with the rise in obesity, metabolic syndrome, and diabetes. Fructose is a major component of added sugars and is distinct from other sugars in its ability to cause intracellular ATP depletion, nucleotide turnover, and the generation of uric acid. In this article, we revisit the hypothesis that it is this unique aspect of fructose metabolism that accounts for why fructose intake increases the risk for metabolic syndrome. Recent studies show that fructose-induced uric acid generation causes mitochondrial oxidative stress that stimulates fat accumulation independent of excessive caloric intake. These studies challenge the long-standing dogma that “a calorie is just a calorie” and suggest that the metabolic effects of food may matter as much as its energy content. The discovery that fructose-mediated generation of uric acid may have a causal role in diabetes and obesity provides new insights into pathogenesis and therapies for this important disease. PMID:24065788

Johnson, Richard J.; Nakagawa, Takahiko; Sanchez-Lozada, L. Gabriela; Shafiu, Mohamed; Sundaram, Shikha; Le, Myphuong; Ishimoto, Takuji; Sautin, Yuri Y.; Lanaspa, Miguel A.

2013-01-01

102

Update on the Pathophysiology and Management of Uric Acid Renal Stones  

Microsoft Academic Search

Idiopathic uric acid nephrolithiasis appears to be increasing in prevalence. While it has long been known that low urine pH\\u000a is associated with uric acid stones, only recently has the pathophysiological basis for this disease emerged. Excessively\\u000a acidic urine is the decisive risk for uric acid lithogenesis, and patients with diabetes and the metabolic syndrome often\\u000a hold the company of

Jon-Emile S. Kenny; David S. Goldfarb

2010-01-01

103

Petroleum Pollution Bioremediation Using Water-Insoluble Uric Acid as the Nitrogen Source  

PubMed Central

The biodegradation of hydrocarbon pollutants in open systems is limited by the availability of a utilizable nitrogen source. This limitation can be overcome by using uric acid. Enrichment cultures grown on crude oil-uric acid media yielded mixed and pure cultures that degraded petroleum. In a simulated open system, uric acid bound to crude oil and was available for bacterial growth and petroleum biodegradation. PMID:14532103

Koren, Omry; Knezevic, Vishnia; Ron, Eliora Z.; Rosenberg, Eugene

2003-01-01

104

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

105

Pro-inflammatory effects of uric acid in the gastrointestinal tract.  

PubMed

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. PMID:24377830

Crane, John K; Mongiardo, Krystin M

2014-01-01

106

What Is a Urea Cycle Disorder?  

MedlinePLUS

... urea cycle. These enzymes are responsible for removing ammonia from the blood stream. The urea cycle involves ... disorders, the nitrogen accumulates in the form of ammonia, a highly toxic substance, resulting in hyperammonemia (elevated ...

107

Detection of urinary creatinine using gold nanoparticles after solid phase extraction.  

PubMed

Label-free gold nanoparticles (AuNPs) were utilized in the detection of creatinine in human urine after a sample preparation by extraction of creatinine on sulfonic acid functionalized silica gel. With the proposed sample preparation method, the interfering effects of the urine matrix on creatinine detection by AuNPs were eliminated. Parameters affecting creatinine extraction were investigated. The aggregation of AuNPs induced by creatinine resulted in a change in the surface plasmon resonance signal with a concomitant color change that could be observed by the naked eye and quantified spectrometrically. The effect of AuNP concentration and reaction time on AuNP aggregation was investigated. The method described herein provides a determination of creatinine in a range of 15-40mgL(-1) with a detection limit of 13.7mgL(-1) and it was successfully used in the detection of creatinine in human urine samples. PMID:25546357

Sittiwong, Jarinya; Unob, Fuangfa

2015-03-01

108

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

109

Relative efficiency of prilled urea and urea-supergranules in Java citronella ( Cymbopogon winterianus Jowitt)  

Microsoft Academic Search

A two-year field study was carried out to compare the efficiency of prilled urea and urea-supergranules in the cultivation of a perennial aromatic grass, citronella (Cymbopogon winterianus Jowitt) in a sandy loam soil. Application of 300kg Nha-1 year-1 increased the herb and essential oil yields. Urea-supergranules significantly increased the yields over prilled urea.

EVS Prakasa Rao; Munnu Singh; Narayana; G Chandrasekhara

1984-01-01

110

Expression of urea transporters and their regulation.  

PubMed

UT-A and UT-B families of urea transporters consist of multiple isoforms that are subject to regulation of both acutely and by long-term measures. This chapter provides a brief overview of the expression of the urea transporter forms and their locations in the kidney. Rapid regulation of UT-A1 results from the combination of phosphorylation and membrane accumulation. Phosphorylation of UT-A1 has been linked to vasopressin and hyperosmolality, although through different kinases. Other acute influences on urea transporter activity are ubiquitination and glycosylation, both of which influence the membrane association of the urea transporter, again through different mechanisms. Long-term regulation of urea transport is most closely associated with the environment that the kidney experiences. Low-protein diets may influence the amount of urea transporter available. Conditions of osmotic diuresis, where urea concentrations are low, will prompt an increase in urea transporter abundance. Although adrenal steroids affect urea transporter abundance, conflicting reports make conclusions tenuous. Urea transporters are upregulated when P2Y2 purinergic receptors are decreased, suggesting a role for these receptors in UT regulation. Hypercalcemia and hypokalemia both cause urine concentration deficiencies. Urea transporter abundances are reduced in aging animals and animals with angiotensin-converting enzyme deficiencies. This chapter will provide information about both rapid and long-term regulation of urea transporters and provide an introduction into the literature. PMID:25298340

Klein, Janet D

2014-01-01

111

40 CFR 721.9892 - Alkylated urea.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 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...

2010-07-01

112

40 CFR 721.9892 - Alkylated urea.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 2011-07-01 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...

2011-07-01

113

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. PMID:24827988

Stib?rková, Blanka; Pavlíková, Markéta; Sokolová, Jitka; Kožich, Viktor

2014-01-01

114

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. PMID:22384520

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

2012-01-01

115

Effect of cigarette smoking on plasma uric acid concentrations  

Microsoft Academic Search

Objectives  The purpose of this study was to examine the effect of cigarette smoking on plasma uric acid concentration and to determine\\u000a the correlation between this parameter and the biological tobacco markers, plasma thiocyanate and urinary cotinine.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  The initial study was conducted on 300 subjects; 138 of them were nonsmokers (62 men and 76 women) aged 14–72 years and 162\\u000a were current

Dhouha Haj Mouhamed; Asma Ezzaher; Fadoua Neffati; Wahiba Douki; Lotfi Gaha; Mohamed Fadhel Najjar

116

Cognitive function at 2443 ?mol/l creatinine  

PubMed Central

Background One hallmark of uremia is the impairment of neuro-cognitive function. Anecdotal clinical description from the early days of chronic dialysis therapy impressively illustrates the improvement of those functions by chronic hemodialysis treatment. Fortunately, today, uremia is only rarely observed in industrialized countries as many patients seek medical/nephrological attention prior to the occurrence of deadly complications of uremia. Case presentation We report a rare case of severe uremia and describe the day to day improvement in neuro-cognitive function by dialysis using state of the arte test battery – starting at a serum creatinine of 2443 ?mol/l. Conclusions Especially executive functions, which are assumed to be localized in the frontal cerebral regions, are impaired in severe uremia and improve remarkably with the correction of severe uremia, i.e. initiation of dialysis. PMID:22894168

2012-01-01

117

Rare mutations associating with serum creatinine and chronic kidney disease.  

PubMed

Chronic kidney disease (CKD) is a complex disorder with a strong genetic component. A number of common sequence variants have been found to associate with serum creatinine (SCr), estimated glomerular filtration rate (eGFR) and/or CKD. We imputed 24 million single-nucleotide polymorphisms and insertions/deletions identified by whole-genome sequencing of 2230 Icelanders into 81 656 chip-typed individuals and 112 630 relatives of genotyped individuals over the age of 18 with SCr measurements. The large set of sequenced individuals allowed accurate imputation of variants to a minor allele frequency (MAF) of 0.1%. We tested the imputed variants for association with SCr. In addition to replicating established loci, we discovered missense and loss-of-function variants associating with SCr in three solute carriers (SLC6A19, SLC25A45 and SLC47A1) and two E3 ubiquitin ligases (RNF186 and RNF128). All the variants are within coding sequences and all but one are rare (MAF <2%) with SCr effects between 0.085 and 0.129 standard deviations. These rare variants have a larger effect on SCr than previously reported common variants, explaining 0.5% of the variability of SCr in Icelanders in addition to the 1% already accounted for. We tested the five variants associating with SCr for association with CKD in an Icelandic sample of 15 594 cases and 291 428 controls. Three of the variants also associated with CKD. These variants may either affect kidney function or creatinine synthesis and excretion. Of note were four mutations in SLC6A19 that associate with reduced SCr, three of which have been shown to cause Hartnup disease. PMID:25082825

Sveinbjornsson, Gardar; Mikaelsdottir, Evgenia; Palsson, Runolfur; Indridason, Olafur S; Holm, Hilma; Jonasdottir, Aslaug; Helgason, Agnar; Sigurdsson, Snaevar; Jonasdottir, Adalbjorg; Sigurdsson, Asgeir; Eyjolfsson, Gudmundur Ingi; Sigurdardottir, Olof; Magnusson, Olafur Th; Kong, Augustine; Masson, Gisli; Sulem, Patrick; Olafsson, Isleifur; Thorsteinsdottir, Unnur; Gudbjartsson, Daniel F; Stefansson, Kari

2014-12-20

118

Plasma Uric Acid and the Risk of Type 2 Diabetes in a Chinese Community  

Microsoft Academic Search

BACKGROUND: Previous cross-sectional studies have shown hyperuricemia to be prevalent among individ- uals with metabolic syndrome, but the evidence from prospective studies of an association between uric acid and diabetes risk is limited. We prospectively investi- gated the association between plasma concentrations of uric acid and the incidence of type 2 diabetes in Chinese individuals. METHODS: We conducted a community-based

Kuo-Liong Chien; Ming-Fong Chen; Hsiu-Ching Hsu; Wei-Tien Chang; Ta-Chen Su; Yuan-Teh Lee; Frank B. Hu

119

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

120

Close correlation between visceral fat accumulation and uric acid metabolism in healthy men  

Microsoft Academic Search

We evaluated the effect of accumulation of intraabdominal visceral fat on the metabolism of uric acid in 50 healthy male subjects to elucidate any relationship between such obesity and hyperuricemia. The area of abdominal fat (visceral fat and subcutaneous fat) was measured at the level of the umbilicus by abdominal computed tomographic scanning. Serum and urinary concentrations of uric acid

S. Takahashi; T. Yamamoto; Z. Tsutsumi; Y. Moriwaki; J. Yamakita; K. Higashino

1997-01-01

121

Effect of Infused Glutamine on Uric Acid Synthesis in Chickens Fed High and Low Protein Diets  

Microsoft Academic Search

This study was carried out to clarify the physiological role of glutamine in uric acid synthesis in the metabolic process of chickens. The feeding of a high ( 20% ) protein diet resulted in higher concentration of plasma uric acid and lower concentration of plasma glutamine than the feeding of a low (5%) protein diet. This phenomenon seems to result

YUTAKA KARASAWA; IWAO TASAKI

122

Noninvasive Differentiation of Uric Acid versus Non-Uric Acid Kidney Stones Using Dual-Energy CT  

PubMed Central

Rationale and Objectives To determine the accuracy and sensitivity for dual-energy computed tomography (DECT) discrimination of uric acid (UA) stones from other (non-UA) renal stones in a commercially implemented product. Materials and Methods Forty human renal stones comprising uric acid (n = 16), hydroxyapatite (n = 8), calcium ox-alate (n = 8), and cystine (n = 8) were inserted in four porcine kidneys (10 each) and placed inside a 32-cm water tank anterior to a cadaver spine. Spiral dual-energy scans were obtained on a dual-source, 64-slice computed tomography (CT) system using a clinical protocol and automatic exposure control. Scanning was performed at two different collimations (0.6 mm and 1.2 mm) and within three phantom sizes (medium, large, and extra large) resulting in a total of six image datasets. These datasets were analyzed using the dual-energy software tool available on the CT system for both accuracy (number of stones correctly classified as either UA or non-UA) and sensitivity (for UA stones). Stone characterization was correlated with micro-CT. Results For the medium and large phantom sizes, the DECT technique demonstrated 100% accuracy (40/40), regardless of collimation. For the extra large phantom size and the 0.6-mm collimation (resulting in the noisiest dataset), three (two cystine and one small UA) stones could not be classified (93% accuracy and 94% sensitivity). For the extra large phantom size and the 1.2-mm collimation, the dual-energy tool failed to identify two small UA stones (95% accuracy and 88% sensitivity). Conclusions In an anthropomorphic phantom model, dual-energy CT can accurately discriminate uric acid stones from other stone types. PMID:18035274

Primak, Andrew N.; Fletcher, Joel G.; Vrtiska, Terri J.; Dzyubak, Oleksandr P.; Lieske, John C.; Jackson, Molly E.; Williams, James C.; McCollough, Cynthia H.

2009-01-01

123

Determination of Urinary Creatinine in Washington State Residents via Liquid Chromatography/Tandem Mass Spectrometry  

PubMed Central

A viable, quick, and reliable method for determining urinary creatinine by liquid chromatography/tandem mass spectrometry (LC/MS/MS) was developed and used to evaluate spot urine samples collected for the Washington Environmental Biomonitoring Survey (WEBS): part of the Washington State Department of Health, Public Health Laboratories (PHL). 50?µL of urine was mixed with a 1?:?1 acetonitrile/water solution containing deuterated creatinine as the internal standard and then analyzed by LC/MS/MS. Utilizing electrospray ionization (ESI) in positive mode, the transition ions for creatinine and creatinine-d3 were determined to be 114.0 to 44.1 (quantifier), 114.0 to 86.1 (qualifier), and 117.0 to 47.1 (creatinine-d3). The retention time for creatinine was 0.85 minutes. The linear calibration range was 20–4000?mg/L, with a limit of detection at 1.77?mg/L and a limit of quantitation at 5.91?mg/L. LC/MS/MS and the colorimetric Jaffé reaction were associated significantly (Pearson r = 0.9898 and R2 = 0.9797, ? ? 0.0001). The LC/MS/MS method developed at the PHL to determine creatinine in the spot urine samples had shorter retention times, and was more sensitive, reliable, reproducible, and safer than other LC/MS/MS or commercial methods such as the Jaffé reaction or modified versions thereof.

West, Caroline E.; Rhodes, Blaine N.

2014-01-01

124

Evaluating an alternative method for rapid urinary creatinine determination.  

PubMed

Creatinine (CR) is an endogenously produced chemical that is routinely assayed in urine specimens to assess kidney function and sample dilution. The industry-standard method for CR determination, known as the kinetic Jaffé (KJ) method, relies on an exponential rate of a colorimetric change, and can therefore require automated processing equipment for moderate- to high-throughput analysis (hundreds to thousands of samples per day). This study evaluates an alternative colorimetric method, the "plateau Jaffé" (PJ) method, which utilizes the chemistry of the KJ method, a commercially available kit, and a multipoint calibration curve. This method is amenable to moderate-throughput sample analysis and does not require automated processing equipment. Thirty-two spot urine samples from healthy adult volunteers were analyzed for creatinine concentration (CRc) using the KJ and PJ methods. Samples were also analyzed using a liquid chromatography time-of-flight mass spectrometry (LC-TOF/MS) method, which acted as an analytical control. Replicate measurements of spot samples (natural log-transformed values) were used to estimate method precision, and linear regression models were used to evaluate method accuracy (LC-TOF/MS measurements were considered the analytical benchmark). Measurement precision was comparable across all three methods, with coefficent of variation estimates ranging from 3 to 6%. Regression models generally showed good agreement across methods with R(2) estimates ranging from .996 to .998, slope estimates ranging from .944 to .986, and y-intercept estimates ranging from 0.111 to 0.303. Minor bias (between 2 and 16%) was observed across methods at the tails of the measurement distributions. The provided regression equations can be used to adjust for this bias and to improve CR measurement comparisons across studies employing different methods. Considering these results, the PJ method is a suitable alternative to the industry standard KJ method for urinary CRc determination. It can be implemented for moderate-throughput sample analysis using modest and commonly available lab instrumentation and manual sample preparation techniques. PMID:25072898

Andersen, Erik M; Sobus, Jon R; Strynar, Mark J; Pleil, Joachim D; Nakayama, Shoji F

2014-01-01

125

Characterization of urease from Sporosarcina ureae  

Microsoft Academic Search

Alkaline stable (pH 7.75–12.5) urease from Sporosarcina ureae was purified over 400-fold by ion exchange and hydrophobic interaction chromatography. The cytoplasmic enzyme was remarkably\\u000a active with a specific activity of greater than 9300 ?mol urea degraded min-1 mg protein-1 at pH 7.5, where it has optimal activity. Although S. ureae is closely related to Bacillus pasteurii, known to posses a

Deborah D. McCoy; Aysegul Cetin; Robert P. Hausinger

1992-01-01

126

Simultaneous measurement of diazolidinyl urea, urea, and allantoin in cosmetic samples by hydrophilic interaction chromatography  

Microsoft Academic Search

A new HPLC method for simultaneous measurement of diazolidinyl urea (DU), urea, and allantoin by hydrophilic interaction chromatography using a column packed with triazol-bonded silica particles is described. The calibration curves of DU, urea, and allantoin were linear over the ranges 2.5–125.0, 30–1250, and 0.25–18.75mg\\/L, respectively. The recoveries of DU, urea, and allantoin from homemade cosmetic samples ranged from 92.84%

Takahiro Doi; Keiji Kajimura; Satoshi Takatori; Naoki Fukui; Shuzo Taguchi; Shozo Iwagami

2009-01-01

127

Empirical relationships among oliguria, creatinine, mortality, and renal replacement therapy in the critically ill  

PubMed Central

Purpose The observation periods and thresholds on serum creatinine and urine output defined in the Acute Kidney Injury Network (AKIN) criteria were not empirically derived. By continuously varying creatinine/urine output thresholds as well as observation period, we sought to investigate the empirical relationships among creatinine, oliguria, in-hospital mortality, and receipt of renal replacement therapy (RRT). Methods Using a high-resolution database (MIMIC-II), we extracted data from 17,227 critically ill patients with an in-hospital mortality rate of 10.9%. 14,526 patients had urine output measurements. Various combinations of creatinine/urine output thresholds and observation periods were investigated by building multivariate logistic regression models for in-hospital mortality and RRT predictions. For creatinine, both absolute and percentage increases were analyzed. To visualize the dependence of adjusted mortality and RRT rate on creatinine, urine output, and observation period, we generated contour plots. Results Mortality risk was high when absolute creatinine increase was high regardless of observation period, when percentage creatinine increase was high and observation period was long, and when oliguria was sustained for a long period of time. Similar contour patterns emerged for RRT. The variability in predictive accuracy was small across different combinations of thresholds and observation periods. Conclusions The contour plots presented in this article complement the AKIN definition. A multi-center study should confirm the universal validity of the results presented in this article. PMID:23223822

Mandelbaum, Tal; Lee, Joon; Scott, Daniel J.; Mark, Roger G.; Malhotra, Atul; Howell, Michael D.; Talmor, Daniel

2012-01-01

128

Rate of Kidney Function Decline in Older Adults: A Comparison Using Creatinine and Cystatin C  

Microsoft Academic Search

Background\\/Aims: The aim of this study was to determine the decline in the estimated glomerular filtration rate (eGFR) in elderly persons and to compare estimates based on creatinine and cystatin C. Methods: In the Cardiovascular Health Study, GFR changes in an elderly cohort were estimated from serum creatinine and cystatin C measured at baseline, year 3 and year 7 in

Michael G. Shlipak; Ronit Katz; Bryan Kestenbaum; Linda F. Fried; Anne B. Newman; David S. Siscovick; Lesley Stevens; Mark J. Sarnak

2009-01-01

129

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

130

MECHANISMS OF UREA TOLERANCE IN UREA-ADAPTED POPULATIONS OF DROSOPHILA MELANOGASTER  

Microsoft Academic Search

When behavioral avoidance cannot prevent an animal from being exposed to novel environmental toxins, physiological mechanisms must cope with the toxin and its effects. We are investigating the basis of urea tolerance in populations of Drosophila melanogaster that have been selected to survive and develop in food containing 300 mmol l-1 urea. Previous research has demonstrated that the urea-selected larvae

REGINE ETIENNE; KECHENER FORTUNAT; VALERIE PIERCE

131

Serum creatinine role in predicting outcome after cardiac surgery beyond acute kidney injury  

PubMed Central

Serum creatinine is still the most important determinant in the assessment of perioperative renal function and in the prediction of adverse outcome in cardiac surgery. Many biomarkers have been studied to date; still, there is no surrogate for serum creatinine measurement in clinical practice because it is feasible and inexpensive. High levels of serum creatinine and its equivalents have been the most important preoperative risk factor for postoperative renal injury. Moreover, creatinine is the mainstay in predicting risk models and risk factor reduction has enhanced its importance in outcome prediction. The future perspective is the development of new definitions and novel tools for the early diagnosis of acute kidney injury largely based on serum creatinine and a panel of novel biomarkers. PMID:25276301

Najafi, Mahdi

2014-01-01

132

Urea in rainwater and atmospheric aerosol  

NASA Astrophysics Data System (ADS)

The measurement of urea (CO(NH 2) 2) in rainwater samples from predominantly marine-influenced locations in Bermuda, and Ireland, and in rains and aqueous aerosol extracts from a rural site at UEA, Norwich indicates that urea is not generally a major contributor to atmospheric water-soluble organic nitrogen. At UEA, where anthropogenic and natural sources of urea are expected to be most intense, urea accounts for <10% of rainwater dissolved organic nitrogen (DON), and <1% of the water-soluble fraction of aerosol organic nitrogen. The analysis of size-segregated aerosol samples indicates that the size distribution of urea is quite different from those of ammonium and nitrate. In the less anthropogenically impacted Atlantic sites, rainwater urea was below the detection limits of the colorimetric method used in this study, consistent with expected dilution processes or reaction of urea during transport. However, in a small set of rain samples collected in Tahiti, urea concentrations ranged from 1 to 8 ?mol l -1, accounting for >40% of the DON measured in those samples. This may be a consequence of strong local sources, or it could possibly result from the partial breakdown of other DON compounds to urea during sample transport and storage. However, the similarity in urea concentrations observed in Pacific samples in this present study and in a previous one ( Timperley et al., 1985, Canadian Journal of Fisheries and Aquatic Science42, 1171-1177) suggests that this may reflect a difference in rain chemistry between Atlantic and Pacific rains, perhaps resulting from differences in levels of agricultural urea usage between Asia and the rest of the world.

Cornell, S. E.; Jickells, T. D.; Thornton, C. A.

133

SGLT2 inhibitor lowers serum uric acid through alteration of uric acid transport activity in renal tubule by increased glycosuria.  

PubMed

Sodium glucose cotransporter 2 (SGLT2) inhibitors have been reported to lower the serum uric acid (SUA) level. To elucidate the mechanism responsible for this reduction, SUA and the urinary excretion rate of uric acid (UE(UA)) were analysed after the oral administration of luseogliflozin, a SGLT2 inhibitor, to healthy subjects. After dosing, SUA decreased, and a negative correlation was observed between the SUA level and the UE(UA), suggesting that SUA decreased as a result of the increase in the UE(UA). The increase in UE(UA) was correlated with an increase in urinary D-glucose excretion, but not with the plasma luseogliflozin concentration. Additionally, in vitro transport experiments showed that luseogliflozin had no direct effect on the transporters involved in renal UA reabsorption. To explain that the increase in UE(UA) is likely due to glycosuria, the study focused on the facilitative glucose transporter 9 isoform 2 (GLUT9?N, SLC2A9b), which is expressed at the apical membrane of the kidney tubular cells and transports both UA and D-glucose. It was observed that the efflux of [(14) C]UA in Xenopus oocytes expressing the GLUT9 isoform 2 was trans-stimulated by 10 mm D-glucose, a high concentration of glucose that existed under SGLT2 inhibition. On the other hand, the uptake of [(14) C]UA by oocytes was cis-inhibited by 100 mm D-glucose, a concentration assumed to exist in collecting ducts. In conclusion, it was demonstrated that the UE(UA) could potentially be increased by luseogliflozin-induced glycosuria, with alterations of UA transport activity because of urinary glucose. PMID:25044127

Chino, Yukihiro; Samukawa, Yoshishige; Sakai, Soichi; Nakai, Yasuhiro; Yamaguchi, Jun-ichi; Nakanishi, Takeo; Tamai, Ikumi

2014-10-01

134

SGLT2 inhibitor lowers serum uric acid through alteration of uric acid transport activity in renal tubule by increased glycosuria  

PubMed Central

Sodium glucose cotransporter 2 (SGLT2) inhibitors have been reported to lower the serum uric acid (SUA) level. To elucidate the mechanism responsible for this reduction, SUA and the urinary excretion rate of uric acid (UEUA) were analysed after the oral administration of luseogliflozin, a SGLT2 inhibitor, to healthy subjects. After dosing, SUA decreased, and a negative correlation was observed between the SUA level and the UEUA, suggesting that SUA decreased as a result of the increase in the UEUA. The increase in UEUA was correlated with an increase in urinary d-glucose excretion, but not with the plasma luseogliflozin concentration. Additionally, in vitro transport experiments showed that luseogliflozin had no direct effect on the transporters involved in renal UA reabsorption. To explain that the increase in UEUA is likely due to glycosuria, the study focused on the facilitative glucose transporter 9 isoform 2 (GLUT9?N, SLC2A9b), which is expressed at the apical membrane of the kidney tubular cells and transports both UA and d-glucose. It was observed that the efflux of [14C]UA in Xenopus oocytes expressing the GLUT9 isoform 2 was trans-stimulated by 10 mm d-glucose, a high concentration of glucose that existed under SGLT2 inhibition. On the other hand, the uptake of [14C]UA by oocytes was cis-inhibited by 100 mm d-glucose, a concentration assumed to exist in collecting ducts. In conclusion, it was demonstrated that the UEUA could potentially be increased by luseogliflozin-induced glycosuria, with alterations of UA transport activity because of urinary glucose. PMID:25044127

Chino, Yukihiro; Samukawa, Yoshishige; Sakai, Soichi; Nakai, Yasuhiro; Yamaguchi, Jun-ichi; Nakanishi, Takeo; Tamai, Ikumi

2014-01-01

135

40 CFR 721.9925 - Aminoethylethylene urea methacrylamide.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Aminoethylethylene urea methacrylamide. 721.9925 Section...Substances § 721.9925 Aminoethylethylene urea methacrylamide. (a) Chemical substance...identified generically as an aminoethylethylene urea methacrylamide (PMN...

2010-07-01

136

40 CFR 721.9925 - Aminoethylethylene urea methacrylamide.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 false Aminoethylethylene urea methacrylamide. 721.9925 Section...Substances § 721.9925 Aminoethylethylene urea methacrylamide. (a) Chemical substance...identified generically as an aminoethylethylene urea methacrylamide (PMN...

2011-07-01

137

Combining creatinine and volume kinetics identifies missed cases of acute kidney injury following cardiac arrest  

PubMed Central

Introduction Fluid resuscitation in the critically ill often results in a positive fluid balance, potentially diluting the serum creatinine concentration and delaying diagnosis of acute kidney injury (AKI). Methods Dilution during AKI was quantified by combining creatinine and volume kinetics to account for fluid type, and rates of fluid infusion and urine output. The model was refined using simulated patients receiving crystalloids or colloids under four glomerular filtration rate (GFR) change scenarios and then applied to a cohort of critically ill patients following cardiac arrest. Results The creatinine concentration decreased during six hours of fluid infusion at 1 litre-per-hour in simulated patients, irrespective of fluid type or extent of change in GFR (from 0% to 67% reduction). This delayed diagnosis of AKI by 2 to 9 hours. Crystalloids reduced creatinine concentration by 11 to 19% whereas colloids reduced concentration by 36 to 43%. The greatest reduction was at the end of the infusion period. Fluid dilution alone could not explain the rapid reduction of plasma creatinine concentration observed in 39 of 49 patients after cardiac arrest. Additional loss of creatinine production could account for those changes. AKI was suggested in six patients demonstrating little change in creatinine, since a 52 ± 13% reduction in GFR was required after accounting for fluid dilution and reduced creatinine production. Increased injury biomarkers within a few hours of cardiac arrest, including urinary cystatin C and plasma and urinary Neutrophil-Gelatinase-Associated-Lipocalin (biomarker-positive, creatinine-negative patients) also indicated AKI in these patients. Conclusions Creatinine and volume kinetics combined to quantify GFR loss, even in the absence of an increase in creatinine. The model improved disease severity estimation, and demonstrated that diagnostic delays due to dilution are minimally affected by fluid type. Creatinine sampling should be delayed at least one hour following a large fluid bolus to avoid dilution. Unchanged plasma creatinine post cardiac arrest signifies renal injury and loss of function. Trial registration Australian and New Zealand Clinical Trials Registry ACTRN12610001012066. PMID:23327106

2013-01-01

138

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

139

Deoxyribonucleic acid base composition of Sporosarcina ureae  

Microsoft Academic Search

The guanine + cytosine (GC) content of the DNAs of 11 cultures of Sporosarcina ureae and one culture of Bacillus pasteurii was determined using the methods of Marmur and Doty (1962), Frédéricqet al. (1961), and paper chromatography. The GC content in DNA of Sporosarcina ureae ranges from 39.3 to 44%. Bacillus pasteurii contained 40.4% GC in DNA. Our results support

J. Bohá?ek; M. Kocur; T. Martinec

1968-01-01

140

The GLUT9 Gene Is Associated with Serum Uric Acid Levels  

E-print Network

of America High serum uric acid levels elevate pro-inflammatory­state gout crystal arthropathy and place in individuals at risk of cardiovascular disease [2,3]. High UA levels are causal in gout crystal arthropathy

Abecasis, Goncalo

141

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

142

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. PMID:25061289

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

143

Electrocatalytic characteristics of uric acid oxidation at graphite–zeolite-modified electrode doped with iron (III)  

Microsoft Academic Search

A new method is developed for the catalytic oxidation of uric acid at graphite–zeolite-modified electrode doped with iron (III) (Fe3+Y\\/ZCME). Iron (III) exchanged in zeolite Y act as catalyst to oxidize uric acid. First, the electrochemical behavior of iron (III) incorporated in the zeolite Y-modified electrode was studied. The results illustrate that diffusion controls the ferric\\/ferrous redox process at the

M. Mazloum Ardakani; Z. Akrami; H. Kazemian; H. R. Zare

2006-01-01

144

Renal Handling of Uric Acid in Normal Subjects by Means of the Pyrazinamide and Probenecid Tests  

Microsoft Academic Search

Pyrazinamide and probenecid tests were used to study the renal mechanisms for urate excretion in 10 normal subjects in the state of low serum uric acid levels (below 3.5 mg\\/dl), normal serum urate concentrations (between 3.6 and 6.4 mg\\/dl) and high serum uric acid levels (above 6.5 mg\\/dl). Presecretory reabsorption of urate was above 99% in all three conditions of

García Puig; Mateos Anton; Muñoz Sanz; G. Gaspar; A. Lesmes; T. Ramos; Ortíz Vázquez

1983-01-01

145

Disposable luminol copolymer-based biosensor for uric acid in urine  

Microsoft Academic Search

A new electrochemiluminescent (ECL) disposable biosensor for uric acid was manufactured by immobilization in a double-layer design of luminol as a copolymer with 3,3?,5,5?-tetramethylbenzidine (TMB) and the enzyme uricase in chitosan on gold screen-printed cells. The good mechanical and improved electroluminescent characteristics of the new copolymer poly(luminol–TMB) make it possible to determine uric acid by measuring the growing ECL emission

J. Ballesta-Claver; I. F. Díaz Ortega; M. C. Valencia-Mirón; L. F. Capitán-Vallvey

2011-01-01

146

Uric Acid Promotes Left Ventricular Diastolic Dysfunction in Mice Fed a Western Diet.  

PubMed

The rising obesity rates parallel increased consumption of a Western diet, high in fat and fructose, which is associated with increased uric acid. Population-based data support that elevated serum uric acids are associated with left ventricular hypertrophy and diastolic dysfunction. However, the mechanism by which excess uric acid promotes these maladaptive cardiac effects has not been explored. In assessing the role of Western diet-induced increases in uric acid, we hypothesized that reductions in uric acid would prevent Western diet-induced development of cardiomyocyte hypertrophy, cardiac stiffness, and impaired diastolic relaxation by reducing growth and profibrotic signaling pathways. Four-weeks-old C57BL6/J male mice were fed excess fat (46%) and fructose (17.5%) with or without allopurinol (125 mg/L), a xanthine oxidase inhibitor, for 16 weeks. The Western diet-induced increases in serum uric acid along with increases in cardiac tissue xanthine oxidase activity temporally related to increases in body weight, fat mass, and insulin resistance without changes in blood pressure. The Western diet induced cardiomyocte hypertrophy, myocardial oxidative stress, interstitial fibrosis, and impaired diastolic relaxation. Further, the Western diet enhanced activation of the S6 kinase-1 growth pathway and the profibrotic transforming growth factor-?1/Smad2/3 signaling pathway and macrophage proinflammatory polarization. All results improved with allopurinol treatment, which lowered cardiac xanthine oxidase as well as serum uric acid levels. These findings support the notion that increased production of uric acid with intake of a Western diet promotes cardiomyocyte hypertrophy, inflammation, and oxidative stress that lead to myocardial fibrosis and associated impaired diastolic relaxation. PMID:25489061

Jia, Guanghong; Habibi, Javad; Bostick, Brian P; Ma, Lixin; DeMarco, Vincent G; Aroor, Annayya R; Hayden, Melvin R; Whaley-Connell, Adam T; Sowers, James R

2014-12-01

147

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. PMID:23441187

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

2013-01-01

148

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. PMID:22900135

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

2012-01-01

149

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. PMID:24877124

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

2014-01-01

150

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. H.; Champion, Paolo C.; Glickman, Randolph D.; Wollin, Timothy A.; Denstedt, John D.

1999-06-01

151

Serum uric acid and the risk of respiratory disease: a population-based cohort study  

PubMed Central

Introduction Uric acid is the most abundant molecule with antioxidant properties found in human blood serum. We examined the relationship between serum uric acid and the incidence of respiratory disease including any effect modification by smoking status. Methods A cohort with serum uric acid measured between 1 January 2000 and 31 December 2012 was extracted from The Health Improvement Network primary care research database. New diagnoses of COPD and lung cancer were ascertained based on diagnostic codes entered into the medical records. Results During 1?002?496 person years (PYs) of follow-up, there were 3901 COPD diagnoses and 1015 cases of lung cancer. After multivariable adjustment, strong interactions with smoking status were detected (p<0.001) for both outcomes with significant negative relationships between serum uric acid and respiratory disease for current smokers but no strong relationships for never-smokers or ex-smokers. The relationships were strongest for lung cancer in heavy smokers (?20 cigarettes per day) with predicted incidence rates 97 per 10?000 PYs (95% CI 68 to 126) in the lowest serum uric acid quintile (100–250?µmol/L) compared with a predicted 28 per 10?000 PYs (95% CI 14 to 41) in the highest quintile (438–700?µmol/L). Conclusions Low levels of serum uric acid are associated with higher rates of COPD and lung cancer in current smokers after accounting for conventional risk factors. PMID:24904021

Horsfall, Laura J; Nazareth, Irwin; Petersen, Irene

2014-01-01

152

The influence of the extracellular fluid volume on the tubular reabsorption of uric acid.  

PubMed Central

Changes is tubular reabsorption of uric acid in response to alterations in the extracellular fluid volume (ECFV) were examined in rats by clearance studies and by direct intratubular microinjections. Contraction of the ECFV led to a rise in the serum uric acid concentration and a 47% decrease in the clearance of uric acid. The ratio of uric acid to inulin clearance also fell, indicating an increase in the net tubular reabsorption of urate. Volume expansion resulted in an increase in the urate clearance and a 37% decrease in the net tubular reabsorption of uric acid. To localize the site in the nephron where these changes occur, microinjections of [2-14C]urate were performed. The lack of conversion of radioactive urate to allantoin after microinjections was demonstrated by thin-layer chromatography. After contraction of the ECFV, urinary recoveries of uric acid were significantly decreased after microinjections into proximal tubular sites. In contrast, recoveries were increased from these proximal sites after volume expansion. No evidence for distral reabsorption was obtained in any group of animals. These studies demonstrate that net urate reabsorption is influenced by the state of hydration of the ECFV and that these alterations are mediated by changes in the rates of reabsorption in the proximal tubule. PMID:1127100

Weinman, E J; Eknoyan, G; Suki, W N

1975-01-01

153

Estimated Glomerular Filtration Rate —A More Stable Indicator than Creatinine Clearance in Peritoneal Dialysis Practice  

PubMed Central

Objective: The usefulness of estimated glomerular filtration rate may not be restricted to pre-dialysis patients, since we reported that estimated glomerular filtration rate was well correlated with measured total creatinine clearance in peritoneal dialysis patients. To clarify the clinical usefulness of estimated glomerular filtration rate as a parameter for peritoneal dialysis adequacy, we retrospectively surveyed estimated glomerular filtration rate and total creatinine clearance in peritoneal dialysis patients treated at JA Toride Medical Center. Patients and Methods: A total of 114 data sets of estimated glomerular filtration rate and total creatinine clearance from 21 PD patients treated at JA Toride Medical Center were collected from November 2010 to October 2011. The patients consisted of 15 men and six women with an average age of 66.6 ± 12.6 years (46–95 years old). The average number of samples was 5.4 ± 1.5 (2 to 7) per patient. Results: The collected data showed less correlation of estimated glomerular filtration rate and total creatinine clearance (r. = 0.435) than that of a previous cross-sectional study (r. = 0.836). As reported in pre-dialysis patients, the differences between estimated glomerular filtration rate and total creatinine clearance were correlated with total creatinine excretion in urine and PD effluent (r. = 0.821). The differences were also correlated with normalized protein catabolic rate, which was one of the main determinant factors for total creatinine excretion (r. = 0.636). A similar tendency was apparently observed in one patient with poor compliance to diet therapy and fluctuating dietary intake. From the analysis of these data, serum creatinine seemed to fluctuate less possibly due to compensatory capacity of the residual renal function in small solute clearance. Conclusions: Consequently, estimated glomerular filtration rate was turned out to be a more stable parameter than total creatinine clearance, which might be a desirable feature in long-term follow-up of peritoneal dialysis patients.

Maeda, Yoshitaka; Yoshida, Sayaka; Hirai, Toshiyuki; Kawasaki, Tomoki; Kuyama, Tamaki

2013-01-01

154

Comparative transport efficiencies of urea analogues through urea transporter UT-B.  

PubMed

Expression of urea transporter UT-B confers high urea permeability to mammalian erythrocytes. Erythrocyte membranes also permeate various urea analogues, suggesting common transport pathways for urea and structurally similar solutes. In this study, we examined UT-B-facilitated passage of urea analogues and other neutral small solutes by comparing transport properties of wildtype to UT-B-deficient mouse erythrocytes. Stopped-flow light-scattering measurements indicated high UT-B permeability to urea and chemical analogues formamide, acetamide, methylurea, methylformamide, ammonium carbamate, and acrylamide, each with P(s)>5.0 x 10(-6) cm/s at 10 degrees C. UT-B genetic knockout and phloretin treatment of wildtype erythrocytes similarly reduced urea analogue permeabilities. Strong temperature dependencies of formamide, acetamide, acrylamide and butyramide transport across UT-B-null membranes (E(a)>10 kcal/mol) suggested efficient diffusion of these amides across lipid bilayers. Urea analogues dimethylurea, acryalmide, methylurea, thiourea and methylformamide inhibited UT-B-mediated urea transport by >60% in the absence of transmembrane analogue gradients, supporting a pore-blocking mechanism of UT-B inhibition. Differential transport efficiencies of urea and its analogues through UT-B provide insight into chemical interactions between neutral solutes and the UT-B pore. PMID:17506977

Zhao, Dan; Sonawane, N D; Levin, Marc H; Yang, Baoxue

2007-07-01

155

Nitrogen in stored poultry litter: uric Acid and xanthine.  

PubMed

Laboratory incubations of four broiler litter (BL) samples at 30°C were performed to investigate the effect of water content on the decay of uric acid nitrogen (UAN) and xanthine nitrogen (XN). UAN and XN concentrations increased in all samples during a period of 1 to 8 d before declining for the remaining 30 d. The increases may be the result of guanine and adenine catabolism. The slopes of linear equations fit to the natural log of the observations from 16 sampling points over 38 d were compared using the GLM procedure in SAS and results indicate that both UAN and XN decay significantly ( = 0.05) more rapidly with increasing water content (?). A second study showed significant effects in one of three samples on the decay rate of UAN with additions of flue-gas desulfurization (FGD) gypsum or alum at a water content of 750 g kg BL. The decay rate of XN was not significantly affected. Finally, a simple two-point sampling study on the effect of water potential for the estimation of first order rate equation constants showed a positive relationship between the rate of UAN and XN decay over 28 d as a function of water potential (?): UAN = 0.0054 × ? + 0.1010 ( = 0.9987) and XN = 0.0066 × ? + 0.1101 ( = 0.9285). This is the first study of UAN and XN decay in BL and the findings add to our understanding of mineralizable N from BL. PMID:25602230

Mowrer, Jake; Cabrera, Miguel; Rasmussen, Todd; Cassity-Duffey, Kate

2014-11-01

156

Enzymatic Characterization of a Prokaryotic Urea Carboxylase  

PubMed Central

We identified the first prokaryotic urea carboxylase (UCA) from a member of the alpha subclass of the class Proteobacteria, Oleomonas sagaranensis. This enzyme (O. sagaranensis Uca) was composed of 1,171 amino acids, and its N-terminal region resembled the biotin carboxylase domains of various biotin-dependent carboxylases. The C-terminal region of the enzyme harbored the Met-Lys-Met motif found in biotin carboxyl carrier proteins. The primary structure of the enzyme was 45% identical to that of the urea carboxylase domain of urea amidolyase from Saccharomyces cerevisiae. O. sagaranensis Uca did not harbor the allophanate hydrolase domain found in the yeast enzyme, but a separate gene with structural similarity was found to be adjacent to the uca gene. Purified recombinant O. sagaranensis Uca displayed ATP-dependent carboxylase activity towards urea (Vmax = 21.2 ?mol mg?1 min?1) but not towards acetyl coenzyme A (acetyl-CoA) and propionyl-CoA, indicating that the gene encoded a bona fide UCA and not an acetyl-CoA or propionyl-CoA carboxylase. The enzyme also exhibited high levels of activity towards acetamide and formamide. Kinetic parameters of the enzyme reaction were determined with ATP, urea, acetamide, and formamide. O. sagaranensis could grow on urea, acetamide, and formamide as sole nitrogen sources; moreover, ATP-dependent urea-degrading activity was found in cells grown with urea but not in cells grown with ammonia. The results suggest that the UCA of this organism may be involved in the assimilation of these compounds as nitrogen sources. Furthermore, orthologues of the O. sagaranensis uca gene were found to be widely distributed among Bacteria. This implies that there are two systems of urea degradation in Bacteria, a pathway catalyzed by the previously described ureases and the UCA-allophanate hydrolase pathway identified in this study. PMID:15090492

Kanamori, Takeshi; Kanou, Norihisa; Atomi, Haruyuki; Imanaka, Tadayuki

2004-01-01

157

Incidence, risk factors and prognosis of changes in serum creatinine early after aortic abdominal surgery  

Microsoft Academic Search

Objective  To determine the incidence, risk factors, and prognostic implications of serum creatinine changes following major vascular surgery.Design  Observational study.Settings  University hospital.Patients  Cohort of 599 consecutive patients undergoing elective abdominal aortic surgery.Interventions  Review of prospectively collected data from 1993 to 2004.Measurements and results  The receiver-operator characteristic (ROC) curve analysis was used to detect the best threshold for postoperative elevation in serum creatinine (? Creat) in relation

Christoph Ellenberger; Alexandre Schweizer; John Diaper; Afksendiyos Kalangos; Nicolas Murith; Gregory Katchatourian; Aristote Panos; Marc Licker

2006-01-01

158

Ethnicity is important for creatinine excretion among Inuit and Caucasians in Greenland.  

PubMed

Abstract Background. Human nutrition, contamination and renal function are commonly assessed by the analysis of urine. A complete 24-hour urine sample is the ideal but it is inconvenient and unreliable. Thus, spot urine sampling with creatinine adjustment is widely used. Stratification for age and gender is recommended. Still, ethnicity may influence creatinine excretion. Methods. We collected 104 24-h urine samples among Inuit and non-Inuit living in Greenland. Completeness of sampling was checked by using para-amino benzoic acid (PABA) that also allowed for compensation of creatinine excretion when sampling was incomplete. We measured creatinine using the Jaffe method and PABA by the HPLC method. Results. Participants were recruited from the capital city, a major town and a settlement (n = 36/48/20). They were aged 30-69 years with 78 Inuit and 26 non-Inuit. Inuit were smaller than non-Inuit (Caucasians): height, 163 vs. 177 cm, p < 0.001; weight, 71 vs. 84 kg, p = 0.001 with similar BMI. Creatinine excretion was lower in Inuit compared to non-Inuit (men, 1344/1807 mg/24 h; women 894/1259 mg/24 h; p = 0.002; 0.02). It was influenced by age (p < 0.001), gender (p < 0.001), weight (p = 0.001) and ethnicity (p = 0.030) while not by the intake of the protein-rich Inuit diet in the adjusted analysis. Creatinine excretion was described by: Inuit men, 1925 mg - (13.1 × age); Inuit women, 1701 mg - (17.0 × age). Conclusion. Inuit and Caucasians have different creatinine excretion. It is recommended to stratify by ethnicity in addition to adjustment for age and gender when using creatinine correction of spot urine samples. PMID:25347361

Andersen, Stig; Dehnfeld, Marie; Laurberg, Peter

2015-01-01

159

Elevated uric acid increases blood pressure in the rat by a novel crystal-independent mechanism.  

PubMed

An elevation in circulating serum uric acid is strongly associated with the development of hypertension and renal disease, but whether uric acid has a causal role or whether it simply indicates patients at risk for these complications remains controversial. We tested the hypothesis that uric acid may have a causal role in the development of hypertension and renal disease by examining the effects of mild hyperuricemia in rats. Mild hyperuricemia was induced in rats by providing a uricase inhibitor (oxonic acid) in the diet. Hyperuricemic rats developed elevated blood pressure after 3 weeks, whereas control rats remained normotensive. The development of hypertension was prevented by concurrent treatment with either a xanthine oxidase inhibitor (allopurinol) or a uricosuric agent (benziodarone), both of which lowered uric acid levels. Blood pressure could also be lowered by reducing uric acid levels with either allopurinol or oxonic acid withdrawal. A direct relationship was found between blood pressure and uric acid (r=0.75, n=69), with a 10-mm Hg blood pressure increase for each 0.03-mmol/L (0.5-mg/dL) incremental rise in serum uric acid. The kidneys were devoid of urate crystals and were normal by light microscopy. However, immunohistochemical stains documented an ischemic type of injury with collagen deposition, macrophage infiltration, and an increase in tubular expression of osteopontin. Hyperuricemic rats also exhibited an increase in juxtaglomerular renin and a decrease in macula densa neuronal NO synthase. Both the renal injury and hypertension were reduced by treatment with enalapril or L-arginine. In conclusion, mild hyperuricemia causes hypertension and renal injury in the rat via a crystal-independent mechanism, with stimulation of the renin-angiotensin system and inhibition of neuronal NO synthase. PMID:11711505

Mazzali, M; Hughes, J; Kim, Y G; Jefferson, J A; Kang, D H; Gordon, K L; Lan, H Y; Kivlighn, S; Johnson, R J

2001-11-01

160

Association of Elevated first Trimester Serum Uric Acid Levels with Development of GDM  

PubMed Central

Background: Early intervention and appropriate treatment in patients with GDM will help in preventing the adverse maternal and fetal outcome and protect them from long term complications. Several studies have shown the association of hyperuricemia with GDM. This study was undertaken to find out the association of elevated first trimester uric acid with development of GDM. Materials and Methods: This prospective observational study was conducted in Mahatma Gandhi Medical Collage and Research Institute, Pondicherry, India, between November 2010 and May 2012. A total of 70 pregnant women were included and parameters like age, parity, BMI, history of DM, serum uric acid at <15 weeks and at 24 to 28 weeks and one step test at 24 to 28 weeks were noted and compared. Results: There was no significant correlation between the demographic variables and GDM, but a moderate significance noted between the family history of DM and one step test (p=0.048). Though there is a proportional increase in the serum uric acid with increase in the BMI, it was not statistically significant. A significant correlation was seen between BMI and risk of development of GDM (p= 0.001). Though there is a significant correlation between serum uric acid at <15 weeks and at 24 to 28 weeks, serum uric acid at <15 weeks of gestation is a better predictor of GGI and GDM (Pearson’s correlation = 0.735). Conclusion: There is increase in the risk of development of GDM with increased levels of serum uric acid in the first trimester. Uric acid levels at <15 weeks of gestation is more significantly associated with risk of development of GDM than it’s levels at 24 to 28 weeks of gestation. PMID:25653992

C, Rasika; Ghose, Seetesh

2014-01-01

161

Uric acid suppresses 1 alpha hydroxylase in vitro and in vivo  

PubMed Central

Objective Patients with gout have lower calcitriol levels that improve when uric acid is lowered. The mechanism of these observations is unknown. We hypothesized that uric acid inhibits 1- ?hydroxylase. Materials and methods In vivo, Sprague Dawley rats were randomized to control (n=5), allantoxanamide (n=8), febuxostat (n=5), or allantoxanamide+febuxostat (n=7). Vitamin D, PTH, and 1-?hydroxylase protein were evaluated. In order to directly evaluate the effect of uric acid on 1-?hydroxylase, we conducted a series of dose response and time course experiments in vitro. Nuclear factor ?-B (NF?B) was inhibited pharmacologically. Finally, to evaluate the potential implications of these findings in humans, the association between uric acid and PTH in humans was evaluated in a cross-sectional analysis of data from the NHANES (2003-2006); n= 9773. Results 1,25(OH)2D and 1-?hydroxylase protein were reduced in hyperuricemic rats and improved with febuxostat treatment. Uric acid suppressed 1-?hydroxylase protein and mRNA expression in proximal tubular cells. This was prevented by NF?B inhibition. In humans, for every 1 mg/dL increase in uric acid, the adjusted odds ratio for an elevated PTH (>65 pg/mL) was 1.21 (95% C.I. 1.14, 1.28; P< 0.0001), 1.15 (95% C.I. 1.08, 1.22; P<0.0001), and 1.16 (95% C.I. 1.03, 1.31; P=0.02) for all subjects, subjects with estimated GFR ?60, and subjects with estimated GFR <60 mL/min/1.73 m2 respectively. Conclusion Hyperuricemia suppresses 1-?hydroxylase leading to lower 1,25(OH)2D and higher PTH in rats. Our results suggest this is mediated by NF?B. The association between uric acid and PTH in NHANES suggests potential implications for human disease. PMID:24269076

Chen, Wei; Roncal-Jimenez, Carlos; Lanaspa, Miguel; Smits, Gerard; Chonchol, Michel; Johnson, Richard J; Jalal, Diana

2013-01-01

162

Stable cystatin C serum levels confirm normal renal function in patients with dronedarone-associated increase in serum creatinine.  

PubMed

Dronedarone is a new antiarrhythmic drug for patients with nonpermanent atrial fibrillation (AF). A relatively consistent finding in all trials studying dronedarone was a moderate but significant elevation of serum creatinine. Since dronedarone competes for the same organic cation transporter in the distal renal tubule with creatinine, serum creatinine and its derived estimated glomerular filtration rate might not reflect true renal function in patients on dronedarone. We therefore investigated alternative markers for renal function in these patients. We prospectively included 20 patients with nonpermanent AF in whom dronedarone 400 mg twice daily was started. Patients had normal renal function and serum creatinine; serum cystatin C and creatinine clearance were measured before treatment and 10 and 90 days after treatment started. Mean serum creatinine level for all 20 patients at baseline (day 0) was 84.55 ± 12.14 and 87.8 ± 17.59 µmol/L on day 10. This slight increase in all patients was not significant. Patients were now divided into the predefined groups of "increased creatinine" (increase in serum creatinine level > 1 standard deviation) and "not increased creatinine." Patients with increased creatinine levels (n = 5) showed a significant elevation of serum creatinine levels from day 0 to day 10 (82.4 ± 9.18 to 104.4 ± 12.74 µmol/L; P = .003), whereas change in serum creatinine levels in the not increased creatinine group (n = 15) was not significant. Serum cystatin C levels remained stable in both of these groups (increased creatinine group: 0.76 ± 0.08 to 0.78 ± 0.08 mg/L; P = .65; not increased creatinine group: 0.77 ± 0.108 to 0.77 ± 0.107 mg/L; P = .906). In conclusion, cystatin C represents an easily available and reliable biomarker for estimation of true renal function in patients on dronedarone treatment. PMID:22837540

Duncker, David; Oswald, Hanno; Gardiwal, Ajmal; Lüsebrink, Ulrich; König, Thorben; Schreyer, Hendrik; Klein, Gunnar

2013-03-01

163

Higher baseline serum uric acid is associated with poorer cognition but not rates of cognitive decline in women.  

PubMed

Serum uric acid is a powerful antioxidant that may have neuroprotective properties. While some studies have found that greater serum uric acid is associated with better cognition in older adults, it is also associated with numerous vascular risk factors that increase risk for dementia. Women may also be particularly vulnerable to the vascular effects of elevated uric acid. We previously found that mildly elevated serum uric acid is a biomarker of cognitive dysfunction in older adults, and that this likely is mediated by cerebral ischemic burden. Here we examine both cross-sectional and longitudinal associations between serum uric acid and declines in cognition and functioning in 423 cognitively healthy community-dwelling older women in the Women's Health and Aging Study (WHAS II). We hypothesized that higher serum uric acid would be associated with poorer concurrent functioning and greater declines over 9 years. In linear regression analyses, higher baseline serum uric acid was associated with poorer working memory, with a trend toward slower manual speed and dexterity before and after adjusting for baseline serum uric acid, demographic and health/cardiovascular variables. However, there were no associations for global cognitive functioning, learning/memory, sequencing, verbal fluency, or visuoconstruction. Mixed effects models also revealed no association with subsequent cognitive declines. Future research should examine changes in serum uric acid at earlier periods in the lifespan and their relationships with later cognitive declines. PMID:25446978

Vannorsdall, Tracy D; Kueider, Alexandra M; Carlson, Michelle C; Schretlen, David J

2014-12-01

164

Temporal relationship between uric acid concentration and risk of diabetes in a community-based study population.  

PubMed

Some observational studies have identified elevated uric acid concentration as a risk factor for diabetes, while others have found an inverse relationship. We examined both the association of uric acid level with incident diabetes and the change in uric acid concentration after a diabetes diagnosis. We analyzed data from the Atherosclerosis Risk in Communities (ARIC) Study and quantified the independent association between uric acid level and incident diabetes via Cox proportional hazards models. The association between duration of diabetes and change in uric acid level was examined via linear regression. Among 11,134 participants without diagnosed diabetes at baseline (1987-1989), there were 1,294 incident cases of diabetes during a median of 9 years of follow-up (1987-1998). Uric acid level was associated with diabetes even after adjustment for risk factors (per 1 mg/dL, hazard ratio = 1.18, 95% confidence interval: 1.13, 1.23), and the association remained significant after adjustment for fasting glucose and insulin levels. Among participants with diabetes (n = 1,510), every additional 5 years' duration of diabetes was associated with a 0.10-mg/dL (95% confidence interval: 0.04, 0.15) lower uric acid level after adjustment. We conclude that uric acid concentration rises prior to diagnosis of diabetes and then declines with diabetes duration. Future studies investigating uric acid as a risk factor for cardiovascular disease should adequately account for the impact and timing of diabetes development. PMID:24418684

Juraschek, Stephen P; McAdams-Demarco, Mara; Miller, Edgar R; Gelber, Allan C; Maynard, Janet W; Pankow, James S; Young, Hunter; Coresh, Josef; Selvin, Elizabeth

2014-03-15

165

Successive determination of urinary bilirubin and creatinine employing simultaneous injection effective mixing flow analysis.  

PubMed

A novel four-channel simultaneous injection effective mixing flow analysis (SIEMA) system has been assembled for successive determination of bilirubin and creatinine in urinary samples. The chemical variables and physical parameters in the flow system were optimized for the enhancement of successive analytical performances. The interferences from urine matrices on the determination of bilirubin and creatinine were eliminated to dilute urine samples. The calibration graphs with the optimum conditions were achieved to be in 0.024-5.0 mg L(-1) for bilirubin and 2-100 mg L(-1) for creatinine. The relative standard deviations (RSDs) at 3 mg L(-1) of bilirubin and at 50 mg L(-1) of creatinine for 11 runs were 1.5 and 1.0%, respectively. The limits of detections (3? of blank) for bilirubin and creatinine were 7 µg L(-1) and 0.6 mg L(-1), respectively. The sample throughput for stepwise detection was 22 h(-1). The proposed method was applied to the successive determination of bilirubin and creatinine in urine samples. PMID:25435229

Ponhong, Kraingkrai; Teshima, Norio; Grudpan, Kate; Vichapong, Jitlada; Motomizu, Shoji; Sakai, Tadao

2015-02-01

166

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

167

Gut bacteria recycle uric acid nitrogen in termites: A strategy for nutrient conservation  

PubMed Central

Reticulitermes flavipes termites synthesize uric acid via purine-nucleoside phosphorylase (purine-nucleoside: orthophosphate ribosyltransferase, EC 2.4.2.1) and xanthine dehydrogenase (xanthine:NAD+ oxidoreductase, EC 1.2.1.37), but their tissues lack uricase (urate:oxygen oxidoreductase, EC 1.7.3.3) or any other enzyme that degrades uric acid. Nevertheless, uricolysis occurs in termites, but as an anaerobic process mediated by hindgut bacteria. 14C-Tracer experiments showed that termites transport uric acid from the site of synthesis and storage (fat body tissue) to the site of degradation (hindgut microbiota) via Malpighian tubules. Moveover, [1,3-15N]uric acid dissimilated by gut bacteria in vivo leads to assimilation of 15N into termite tissues. NH3, a product of uricolysis, is a potential N source for termites, either directly via glutamine synthetase [L-glutamate:ammonia ligase (ADP-forming), EC 6.3.1.2] activity of fat body tissue or indirectly through microbe assimilation. Symbiotic recycling of uric acid N appears to be important to N conservation in these oligonitrotrophic insects. PMID:16593064

Potrikus, Catherine J.; Breznak, John A.

1981-01-01

168

Disposable luminol copolymer-based biosensor for uric acid in urine.  

PubMed

A new electrochemiluminescent (ECL) disposable biosensor for uric acid was manufactured by immobilization in a double-layer design of luminol as a copolymer with 3,3',5,5'-tetramethylbenzidine (TMB) and the enzyme uricase in chitosan on gold screen-printed cells. The good mechanical and improved electroluminescent characteristics of the new copolymer poly(luminol-TMB) make it possible to determine uric acid by measuring the growing ECL emission with the analyte concentration. The combination of enzymatic selectivity with ECL sensitivity results in a disposable analytical device with a linear range for uric acid from 1.5×10(-6) to 1.0×10(-4) M, a limit of detection of 4.4×10(-7) M and a precision of 13.1% (1.0×10(-5) M, n=10) as relative standard deviation. Satisfactory results were obtained for uric acid determination in 24h-urine samples compared to a reference procedure. This uric acid biosensor can be used as a low-cost alternative to conventional methods. PMID:21839206

Ballesta-Claver, J; Díaz Ortega, I F; Valencia-Mirón, M C; Capitán-Vallvey, L F

2011-09-30

169

Epitaxial relationships between uric acid crystals and mineral surfaces: a factor in urinary stone formation.  

PubMed

Uric acid (C5H4N4O3) is one of the final products of purine metabolism. Its concentration balance is maintained in the kidneys, but compromised kidney function can result in its crystallization either in the renal tract or in the interstitial fluid of joints. In physiological deposits, crystalline uric acid is most frequently found either in a protonated state (anhydrous or dihydrate phases) or as a deprotonated urate ion (sodium or ammonium salts). Often these precipitates are found in association with a number of mineral phases (e.g., calcium oxalates, calcium phosphates, and magnesium phosphates). Their frequent and common coexistence suggests that synergistic relationships between these crystalline phases may exist. A comprehensive list of different heterogeneous uric acid/uric acid and uric acid/mineral interfaces that are epitaxially matched was generated with the lattice-matching program EpiCalc. Two hundred twenty-five coincident epitaxial matches and four commensurate epitaxial matches were identified using this screening procedure. PMID:15274547

Frincu, M Crina; Fogarty, Caitlin E; Swift, Jennifer A

2004-08-01

170

Back-Calculating Baseline Creatinine with MDRD Misclassifies Acute Kidney Injury in the Intensive Care Unit  

PubMed Central

Background and objectives: The purpose of this study was to assess the viability of back-calculation with the Modification of Diet in Renal Disease (MDRD) formula to determine baseline creatinine on the basis of acute kidney injury (AKI) metrics, RIFLE criteria, and Acute Kidney Injury Network (AKIN) criteria for the purpose of clinical trial outcomes or epidemiology. Design, setting, participants, & measurements: This study was a retrospective analysis of prospectively collected data from patients with measured baseline creatinines before entry to the intensive care unit (ICU). The AKI status was determined using five different baseline creatinines: the measured creatinine (the standard) and an estimated creatinine determined by back-calculation using MDRD assuming a GFR of 75 ml/min (epCr75), 100 ml/min (epCr100), randomly generating a value on a lognormal curve (epCrRnd), and choosing the lowest creatinine value within the first week in the ICU (epCrlow). A subgroup of patients without chronic kidney disease (CKD) was similarly analyzed. Results: Of 224 patients, 70 (31%) had AKI according to RIFLE and 93 (42%) according to AKIN. The epCr75 and epCr100 distributions greatly overestimated the proportion with AKI. The epCrlow overestimated AKI according to AKIN but correctly estimated AKI according to RIFLE. The mean of 1000 epCrRnd distributions correctly estimated AKI according to RIFLE and AKIN. Each estimated distribution performed better in the non-CKD population with the exception of epCrRnd. However, only the epCrlow distribution accurately determined the proportion with AKI. Conclusions: A measured rather than estimated value should be used for baseline creatinine in trials or epidemiologic studies of AKI. PMID:20498242

Endre, Zoltán H.

2010-01-01

171

Serum albumin and creatinine clearance rate among smear positive pulmonary tuberculosis patients in Bangladesh.  

PubMed

This case control study was carried out in the Department of Biochemistry, Mymensingh Medical College in cooperation with the Outpatient Department and Medicine Units of Mymensingh Medical College Hospital, Fulbaria Upazilla Health Complex, Mymensingh and some DOTS centers of BRAC, a non-government organization during the period of July 2006 to June 2007. The aim of the study was to explore the status of serum albumin & creatinine clearance levels in smear positive Bangladeshi pulmonary tuberculosis patients as a means to monitor the possibility of management of these patients as these levels decrease significantly. Serum albumin level was investigated in TB patients for monitoring the nutritional status of TB patients and also for the adjustment of serum calcium level. Creatinine clearance rate was investigated in TB patients for monitoring the impairment of renal function and nutritional depletion in tuberculosis patients. A total of 120 people of different age groups were included in this study. Subjects were divided into two groups- Group I (Control; n=60) - apparently healthy people selected matching by age, sex and socioeconomic status with the cases and Group II (Case; n=60) - people with smear positive pulmonary tuberculosis. Serum albumin was estimated by colorimetric principle. Serum creatinine was also estimated by colorimetric principle & creatinine clearance rate was estimated from serum creatinine by Cockcroft- Gault equation. Statistical analysis was done by using SPSS windows package. Among the groups, mean±SD of serum albumin in Group II (3.74±0.44gm/dl) was significantly lower (p<0.001) than that in Group I (4.85±0.31gm/dl). Mean±SD of creatinine clearance rate in Group II (35.36±8.29ml/min) was also significantly lower than that in Group I (84.16±20.20ml/min). It is evident from the study that serum albumin & creatinine clearance rate levels significantly decrease in smear positive Bangladeshi pulmonary tuberculosis patients. PMID:25178592

Hoque, M R; Chakraborty, P K; Paul, U K; Sarkar, S; Akhter, S; Shahidullah, S M; Gautam, B; Sultana, S; Ferdous, N; Samsunnahar, M

2014-07-01

172

Interference with the Jaffé Method for Creatinine Following 5-Aminolevulinic Acid Administration  

PubMed Central

Background The photosensitizer pro-drug 5-aminolevulinic acid (5-ALA) has been administered systemically for photodynamic therapy. Although several toxicities have been reported, nephrotoxicity has never been observed. Materials and Methods Patients with head and neck mucosal dysplasia have been treated on a phase 1 study of escalating light doses in combination with 60 mg/kg of oral 5-ALA. Serum creatinine was measured with the modified Jaffe method or an enzymatic method in the first 24 hours after 5-ALA. Interference by 5-ALA, as well as by its photosensitizing product protoporphyrin IX, was assessed. Results Among 11 subjects enrolled to date, 9 of 11 had blood chemistries collected within the first 5 hours with 7 demonstrating significant grade 3 creatinine elevations (p=0.030). There was no additional evidence of compromised renal function or increased PDT-induced mucositis. Creatinine levels measured by the Jaffe assay increased linearly as a function of the ex-vivo addition of ALA (p<.0001). The exogenous addition of PpIX did not alter creatinine levels. ALA did not interfere with creatinine levels as measured by an enzymatic assay. A total of 4 of the 11 subjects had creatinine levels prospectively measured by both the Jaffe and the enzymatic assays. Only the Jaffe method demonstrated significant elevations as a function of time after ALA administration. Conclusions The transient increase in creatinine after systematic ALA can be attributed, in part, if not entirely, to interference of ALA in the Jaffe reaction. Alternative assays should be employed in situations calling for monitoring of kidney function after systemic ALA. PMID:21112550

Quon, Harry; Grossman, Craig E.; King, Rebecca L.; Putt, Mary; Donaldson, Keri; Kricka, Larry; Finlay, Jarod; Malloy, Kelly; Cengel, Keith A.; Busch, Theresa M.

2013-01-01

173

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

Technology Transfer Automated Retrieval System (TEKTRAN)

Slow release nitrogen (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 conventional aqueous urea-ammonium nitrate (UAN) [(NH2)2CO, NH4NO3]...

174

An investigation of urea decomposition and selective non-catalytic removal of nitric oxide with urea  

E-print Network

The use of urea (NH2CONH2) to remove nitric oxide (NO) from exhaust streams was investigated using a laboratory laminar-flow reactor. The experiments used a number of gas compositions to simulate different combustion exhaust gases. The urea...

Park, Yong Hun

2004-09-30

175

Ratio of 11-desoxy 17-oxosteroids to creatinine in a population screened for breast cancer.  

PubMed Central

During a population-based screening project for breast cancer, almost 15,000 women aged 50 years and over have provided a 12 h (overnight) sample of urine for research purposes. In 3,789 women the excretion of 11-desoxy-17-oxosteroids (DOOS) and creatinine was measured. Results were analysed in terms of urinary concentrations and of a ratio between DOOS and creatinine. Age had an effect on DOOS, creatinine and their ratio. Body weight and body surface area had an effect on creatinine excretion and therefore on the ratio. The following variables did not have an appreciable effect on the above-mentioned ratio: a family history of breast cancer, parity and age at first pregnancy, menopause and oestrogenic drugs, and parenchymal pattern of the breast as observed on the xeromammogram. Breast cancer was found at first screening in 106 out of 14,697 women. In 100 of these cases DOOS and creatinine were measured. Excretion values expressed as the ratio between the two, allowing for body surface area, did not differ materially from those of 100 age-matched controls. These results lead the authors to the conclusion that the determination of androgen metabolite excretion in women over 50 years of age is of no help in selecting a group at high risk of breast cancer. PMID:444408

Poortman, J.; van der Smissen, J.; Collette, H. J.; de Waard, F.

1979-01-01

176

Plasma creatinine in dogs: intra- and inter-laboratory variation in 10 European veterinary laboratories  

PubMed Central

Background There is substantial variation in reported reference intervals for canine plasma creatinine among veterinary laboratories, thereby influencing the clinical assessment of analytical results. The aims of the study was to determine the inter- and intra-laboratory variation in plasma creatinine among 10 veterinary laboratories, and to compare results from each laboratory with the upper limit of its reference interval. Methods Samples were collected from 10 healthy dogs, 10 dogs with expected intermediate plasma creatinine concentrations, and 10 dogs with azotemia. Overlap was observed for the first two groups. The 30 samples were divided into 3 batches and shipped in random order by postal delivery for plasma creatinine determination. Statistical testing was performed in accordance with ISO standard methodology. Results Inter- and intra-laboratory variation was clinically acceptable as plasma creatinine values for most samples were usually of the same magnitude. A few extreme outliers caused three laboratories to fail statistical testing for consistency. Laboratory sample means above or below the overall sample mean, did not unequivocally reflect high or low reference intervals in that laboratory. Conclusions In spite of close analytical results, further standardization among laboratories is warranted. The discrepant reference intervals seem to largely reflect different populations used in establishing the reference intervals, rather than analytical variation due to different laboratory methods. PMID:21477356

2011-01-01

177

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

178

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

179

Analysis of oxonic acid, uric acid, creatine, allantoin, xanthine and hypoxanthine in poultry litter by reverse phase HPLC  

Microsoft Academic Search

A separation method has been developed to extract organic compounds from poultry manure and litter and subsequently analyze these extracts using reverse phase high-pressure liquid chromatography. Specifically, the method may be used to quantify oxonic acid, allantoin, creatine, uric acid, xanthine and hypoxanthine in poultry manure samples. In a representative sample of fresh poultry manure, oxonic acid, allantoin, creatine, uric

M. A. Eiteman; R. M. Gordillo; M. L. Cabrera

1994-01-01

180

The rate and pattern of urea infusion into the rumen of wethers alters nitrogen balance and plasma ammonia.  

PubMed

Changes in N balance, urinary excretion of purine derivative (PD), urea, creatinine and ammonia and plasma ammonia, glucose, urea, insulin and IGF-1 were examined in four wethers (37 ± 2.6 kg BW). The animals were fitted with permanent ruminal catheters, fed lucerne hay (9.4 MJ/day; 23 g N/day; 7 g soluble N/day, 6 equal meals/day) and treated with contrasting rates of urea infusion into the rumen: first, a continuous infusion (CT), at 3.2 mg urea-N/min for 10 days and then a discontinuous infusion (DT) at 156 mg urea-N/min for 4 min; in 6 daily doses with the meals for 7 days. N balance was calculated from pooled samples of faeces and urine. Jugular blood samples were collected before and 1.5 h after the morning meal (M1) on days CT10, DT2, DT4 and DT6. N retention decreased during DT (p = 0.01) due to a significant increase of N excretion in urine (4 g/day; p = 0.009) and faeces (1 g/day; p = 0.02). Dry matter (p < 0.001) and N digestibility in vivo (p = 0.01) decreased significantly during DT. Urinary urea and PD excretion were not altered by treatment. Significant linear (p = 0.004) and quadratic (p = 0.001) effects were observed for plasma ammonia in M1 (from 170 CT10 to 235 ?m DT2 and returned to 120 ?m DT6). No changes were observed in plasma glucose, urea, insulin and IGF-1. Results indicate that changes from CT to DT reduced N retention in sheep due to enhanced urinary N excretion, but it was not associated with changes in urinary urea or PD excretion; or plasma concentrations of insulin and IGF-1. As the dry matter (DM) an N digestibility could account a 0.23 of the decrease in N retention; the largest fraction of the reduction in N retention remained unexplained by the results. PMID:24611997

Recavarren, M I; Milano, G D

2014-12-01

181

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

182

The relationship between uric acid and its oxidative product allantoin: a potential indicator for the evaluation of oxidative stress in birds  

Microsoft Academic Search

Uric acid is the main nitrogenous waste product in birds but it is also known to be a potent antioxidant. Hominoid primates and birds lack the enzyme urate oxidase, which oxidizes uric acid to allantoin. Consequently, the presence of allantoin in their plasma results from non-enzymatic oxidation. In humans, the allantoin to uric acid ratio in plasma increases during oxidative

Ella Tsahar; Zeev Arad; Ido Izhaki; Christopher G. Guglielmo

2006-01-01

183

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

184

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. PMID:23638369

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

2013-01-01

185

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

186

Raman spectroscopic approach to monitor the in vitro cyclization of creatine ? creatinine  

NASA Astrophysics Data System (ADS)

The creatine ? creatinine cyclization, an important metabolic phenomenon has been initiated in vitro at acidic pH and studied through Raman spectroscopic and DFT approach. The equilibrium composition of neutral, zwitterionic and protonated microspecies of creatine has been monitored with time as the reaction proceeds. Time series Raman spectra show clear signature of creatinine formation at pH 3 after ?240 min at room temperature and reaction is faster at higher temperature. The spectra at pH 1 and pH 5 do not show such signature up to 270 min implying faster reaction rate at pH 3.

Gangopadhyay, Debraj; Sharma, Poornima; Singh, Sachin Kumar; Singh, Pushkar; Tarcea, Nicolae; Deckert, Volker; Popp, Jürgen; Singh, Ranjan K.

2015-01-01

187

Undernutrition and serum and urinary urea nitrogen of white-tailed deer during winter  

USGS Publications Warehouse

Direct, practical means of assessing undernutrition in deer (Odocoileus spp.) and other ungulates during winter are needed in areas of research and management. We examined the relationship between mass loss and serum urea nitrogen (SUN) and urinary urea nitrogen:creatinine (U:C) in captive white-tailed deer (O. virginianus). During 4 February-5 May 1988, we maintained 7 adult white-tailed deer on various feeding regimes to simulate natural nutritional restriction during winter. Mass loss was greater (P = 0.037) in deer (17.0-32.2%) fed restricted amounts of a low protein low energy diet versus control deer (7.0-17.4%) fed the same diet ad libitum. Serum triiodothyronine (T3) concentrations did not differ (P = 0.191) between groups, but declined (P = 0.001) as nutrition declined. Slopes of percent mass lossSUN and urinary U:C relationships were positive (P = 0.008 and 0.055) in 7 and 6 deer, respectively. Mean U:C was directly related (r2 = 0.52, P = 0.040) to mean cumulative mass loss, whereas mean SUN was not (r2 = 0.29, P = 0.125). Data presented support the potential of urinary U:C as an index of winter nutritional condition of white-tailed deer; however, additional research is required to provide a complete understanding of this index's utility under field conditions.

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

1994-01-01

188

Comparison of serum creatinine and serum cystatin C as biomarkers to detect sepsis-induced acute kidney injury and to predict mortality in CD-1 mice.  

PubMed

Acute kidney injury (AKI) dramatically increases sepsis mortality, but AKI diagnosis is delayed when based on serum creatinine (SCr) changes, due in part, to decreased creatinine production. During experimental sepsis, we compared serum cystatin C (sCysC), SCr, and blood urea nitrogen (BUN) to inulin glomerular filtration rate (iGFR) before or 3-18 h after cecal ligation and puncture (CLP)-induced sepsis in CD-1 mice. sCysC had a faster increase and reached peak levels more rapidly than SCr in both sepsis and bilateral nephrectomy (BiNx) models. sCysC was a better surrogate of iGFR than SCr during sepsis. Combining sCysC with SCr values into a composite biomarker improved correlation with iGFR better than any biomarker alone or any other combination. We determined the renal contribution to sCysC handling with BiNx. sCysC and SCr were lower post-BiNx/CLP than post-BiNx alone, despite increased inflammatory and nonrenal organ damage biomarkers. Sepsis decreased CysC production in nephrectomized mice without changing body weight or CysC space. Sepsis decreased sCysC production and increased nonrenal clearance, similar to effects of sepsis on SCr. sCysC, SCr, and BUN were measured 6 h postsepsis to link AKI with mortality. Mice with above-median sCysC, BUN, or SCr values 6 h postsepsis died earlier than mice with below-median values, corresponding to a substantial AKI association with sepsis mortality in this model. sCysC performs similarly to SCr in classifying mice at risk for early mortality. We conclude that sCysC detects AKI early and better reflects iGFR in CLP-induced sepsis. This study shows that renal biomarkers need to be evaluated in specific contexts. PMID:25143457

Leelahavanichkul, Asada; Souza, Ana Carolina P; Street, Jonathan M; Hsu, Victor; Tsuji, Takayuki; Doi, Kent; Li, Lingli; Hu, Xuzhen; Zhou, Hua; Kumar, Parag; Schnermann, Jürgen; Star, Robert A; Yuen, Peter S T

2014-10-15

189

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. PMID:23562957

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

190

Urea recycling from the renal pelvis in sheep: A study with ( sup 14 C)urea  

SciTech Connect

To test the hypothesis that urea can be recycled from the renal pelvis, (14C)urea diluted in native urine (1 microCi/ml) was perfused (0.5 ml/min) into one of the pelvises of sheep fed either normal (NP) or low (LP)-protein diets. Blood samples were obtained from the ipsilateral renal vein and from the carotid artery throughout the perfusions. 14C activity determinations in urine and plasma demonstrated a flux of (14C)urea from the pelvis to renal vein blood (40,000 in NP and 130,000 disintegrations/min in LP sheep, P less than 0.01). The corresponding flux of native urea was only 1.5 times higher in NP than in LP sheep (6.8 +/- 1.1 vs. 4.7 +/- 2.9 mumol/min, not significant) despite their 8 times higher urinary concentration of urea. The fraction of filtered urea that was reabsorbed in the pelvis was larger in LP sheep (7.5 +/- 3.7 vs. 1.9 +/- 0.7% in NP sheep, P less than 0.05). A fraction of urea is thus actually recycled from the renal pelvis in sheep, and this pelvic retention is enhanced in LP animals. The importance of this phenomenon in the nitrogen economy is discussed.

Cirio, A.; Boivin, R. (Ecole Nationale Veterinaire de Lyon, Marcy l'Etoile (France))

1990-05-01

191

All Solid-State Potentiometric Biosensors for Creatinine Determination Based on pH and Ammonium Electrodes  

Microsoft Academic Search

This work investigates a disposable creatinine potentiometric biosensor based on a pH-sensitive electrode and an ammonium ion-selective electrode. An enzyme, creatinine iminohydrolase (CIH) was immobilized directly onto the surface of the electrodes by the entrapment method. According to the experimental results, the creatinine biosensors based on the pH-sensitive electrode and ammonium ion-selective electrode show a rapid response time (t95 <

Nien-Hsuan Chou; Jung-Chuan Chou; Tai-Ping Sun; Shen-Kan Hsiung

2009-01-01

192

Urea synthesis in enterocytes of developing pigs.  

PubMed Central

Urea synthesis from ammonia, glutamine and arginine was determined in enterocytes from newborn (0-day-old), 2-21-day-old suckling, and 29-58-day-old post-weaning pigs. Pigs were weaned at 21 days of age. Cells were incubated for 30 min at 37 degrees C in Krebs-Henseleit bicarbonate buffer (pH 7.4) containing (i) 0.5-2 mM NH4Cl plus 0.05-2 mM ornithine and 2 mM aspartate, (ii) 1-5 mM glutamine, or (iii) 0.5-2 mM arginine. In enterocytes from newborn and suckling pigs, there was no measurable synthesis of urea from ammonia, glutamine or arginine, and analysis of amino acids by a sensitive fluorimetric HPLC method revealed the formation of negligible amounts of ornithine from arginine. In contrast, in cells from post-weaning pigs, relatively large amounts of urea and ornithine were produced from ammonia, glutamine and arginine in a dose-dependent manner. To elucidate the mechanism of the developmental change of urea synthesis in pig enterocytes, the activities of urea-cycle enzymes were determined. The activities of enterocyte carbamoyl phosphate synthase I and ornithine carbamoyltransferase were lower in post-weaning pigs than in suckling ones, whereas there was no difference in arginino-succinate lyase. The activities of argininosuccinate synthase and arginase were increased by 4-fold and 50-100-fold, respectively, in enterocytes from post-weaning pigs compared with suckling pigs. The induction of arginase appears to be sufficient to account for the formation of urea from ammonia, glutamine and arginine in post-weaning pig enterocytes. These results demonstrate for the first time the presence of synthesis of urea from extracellular or intramitochondrially generated ammonia in enterocytes of post-weaning pigs. This hitherto unrecognized urea synthesis in these cells may be a first line of defence against the potential toxicity of ammonia produced by the extensive intestinal degradation of glutamine (a major fuel for enterocytes) and derived from diet and luminal micro-organisms. PMID:8554511

Wu, G

1995-01-01

193

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. PMID:24783172

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

2014-01-01

194

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

195

Uric Acid in the Tapetum Lucidum of Mooneyes Hiodon (Hiodontidae Teleostei)  

Microsoft Academic Search

Tapeta lucida (ocular reflectors) of mooneyes, Hiodon tergisus and H. alosoides, lie in the pigment epithelium, the processes of which are packed with reflecting particles and also contain melanin granules. The reflecting particles are tiny birefringent crystals. On the basis of chromatography, u.v. spectroscopy and enzymic degradation (with uricase), it is concluded that the reflecting material contains uric acid. Mooneye

E. S. Zyznar; F. B. Cross; J. A. C. Nicol

1978-01-01

196

21 CFR 862.1770 - Urea nitrogen test system.  

Code of Federal Regulations, 2014 CFR

...Identification. A urea nitrogen test system is a device intended to measure urea nitrogen (an end-product of nitrogen metabolism) in whole blood, serum, plasma, and urine. Measurements obtained by this device are used in the diagnosis and...

2014-04-01

197

21 CFR 862.1770 - Urea nitrogen test system.  

Code of Federal Regulations, 2013 CFR

...Identification. A urea nitrogen test system is a device intended to measure urea nitrogen (an end-product of nitrogen metabolism) in whole blood, serum, plasma, and urine. Measurements obtained by this device are used in the diagnosis and...

2013-04-01

198

Urea retranslocation from senescing Arabidopsis leaves is promoted by DUR3-mediated urea retrieval from leaf apoplast.  

PubMed

In plants, urea derives either from root uptake or protein degradation. Although large quantities of urea are released during senescence, urea is mainly seen as a short-lived nitrogen (N) catabolite serving urease-mediated hydrolysis to ammonium. Here, we investigated the roles of DUR3 and of urea in N remobilization. During natural leaf senescence urea concentrations and DUR3 transcript levels showed a parallel increase with senescence markers like ORE1 in a plant age- and leaf age-dependent manner. Deletion of DUR3 decreased urea accumulation in leaves, whereas the fraction of urea lost to the leaf apoplast was enhanced. Under natural and N deficiency-induced senescence DUR3 promoter activity was highest in the vasculature, but was also found in surrounding bundle sheath and mesophyll cells. An analysis of petiole exudates from wild-type leaves revealed that N from urea accounted for >13% of amino acid N. Urea export from senescent leaves further increased in ureG-2 deletion mutants lacking urease activity. In the dur3 ureG double insertion line the absence of DUR3 reduced urea export from leaf petioles. These results indicate that urea can serve as an early metabolic marker for leaf senescence, and that DUR3-mediated urea retrieval contributes to the retranslocation of N from urea during leaf senescence. PMID:25440717

Bohner, Anne; Kojima, Soichi; Hajirezaei, Mohammad; Melzer, Michael; von Wirén, Nicolaus

2015-02-01

199

Difficulties in diagnosing acute kidney injury post liver transplantation using serum creatinine based diagnostic criteria  

PubMed Central

Renal function in patients with advanced cirrhosis is an important prognostic factor for survival both prior to and following liver transplantation. The importance of renal function is reflected by the introduction of the model for end stage liver disease (MELD) score, which includes serum creatinine. The MELD score has been shown to predict the short term risk of death for transplant wait listed patients and is currently used by many countries to allocate liver transplants on the basis of severity of underlying illness. Changes in serum creatinine are also used to stage acute kidney injury. However prior to liver transplantation the serum creatinine typically over estimates underlying renal function, particularly when a colorimetric Jaffe based assay is used, and paradoxically then under estimates renal function post liver transplantation, particularly when immunophyllins are started early as part of transplant immunosuppression. As acute kidney injury is defined by changes in serum creatinine, this potentially leads to over estimation of the incidence and severity of acute kidney injury in the immediate post-operative period. PMID:25349641

Agarwal, Banwari; Davenport, Andrew

2014-01-01

200

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. PMID:20555318

Waikar, Sushrut S.; Sabbisetti, Venkata S.; Bonventre, Joseph V.

2011-01-01

201

A Comparison of Daily Rhythm of Creatinine and Creatine Kinase in the Sedentary and Athlete Horse  

Microsoft Academic Search

The goal of this study was to investigate the existence of a daily rhythm of creatinine or creatine kinase (CK) and the influence of physical exercise on these rhythms. Blood samples from 20 Sella Italiana horses were collected every 4 hours for 48 consecutive hours via an intravenous cannula inserted into the jugular vein. The horses were divided into two

Giuseppe Piccione; Claudia Giannetto; Francesco Fazio; Stefania Casella; Giovanni Caola

2009-01-01

202

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...

203

Creatinine Measurements in 24 h Urine by Liquid Chromatography-Tandem Mass Spectrometry  

E-print Network

Creatinine Measurements in 24 h Urine by Liquid Chromatography-Tandem Mass Spectrometry EUN, Davis, California 95616 A simple, sensitive, and specific liquid chromatography-tandem mass spectrometry chromatography (HPLC) (17­19), and liquid chromatography-tandem mass spectrometry (LC-MS/MS) (20, 21) method. LC

Hammock, Bruce D.

204

Uric Acid Promotes Apoptosis in Human Proximal Tubule Cells by Oxidative Stress and the Activation of NADPH Oxidase NOX 4  

PubMed Central

Mild hyperuricemia has been linked to the development and progression of tubulointerstitial renal damage. However the mechanisms by which uric acid may cause these effects are poorly explored. We investigated the effect of uric acid on apoptosis and the underlying mechanisms in a human proximal tubule cell line (HK-2). Increased uric acid concentration decreased tubule cell viability and increased apoptotic cells in a dose dependent manner (up to a 7-fold increase, p<0.0001). Uric acid up-regulated Bax (+60% with respect to Ctrl; p<0.05) and down regulated X-linked inhibitor of apoptosis protein. Apoptosis was blunted by Caspase-9 but not Caspase-8 inhibition. Uric acid induced changes in the mitochondrial membrane, elevations in reactive oxygen species and a pronounced up-regulation of NOX 4 mRNA and protein (p<0.05). In addition, both reactive oxygen species production and apoptosis was prevented by the NADPH oxidase inhibitor DPI as well as by Nox 4 knockdown. URAT 1 transport inhibition by probenecid and losartan and its knock down by specific siRNA, blunted apoptosis, suggesting a URAT 1 dependent cell death. In summary, our data show that uric acid increases the permissiveness of proximal tubule kidney cells to apoptosis by triggering a pathway involving NADPH oxidase signalling and URAT 1 transport. These results might explain the chronic tubulointerstitial damage observed in hyperuricaemic states and suggest that uric acid transport in tubular cells is necessary for urate-induced effects. PMID:25514209

Verzola, Daniela; Ratto, Elena; Villaggio, Barbara; Parodi, Emanuele Luigi; Pontremoli, Roberto; Garibotto, Giacomo; Viazzi, Francesca

2014-01-01

205

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

206

Uric Acid Promotes Apoptosis in Human Proximal Tubule Cells by Oxidative Stress and the Activation of NADPH Oxidase NOX 4.  

PubMed

Mild hyperuricemia has been linked to the development and progression of tubulointerstitial renal damage. However the mechanisms by which uric acid may cause these effects are poorly explored. We investigated the effect of uric acid on apoptosis and the underlying mechanisms in a human proximal tubule cell line (HK-2). Increased uric acid concentration decreased tubule cell viability and increased apoptotic cells in a dose dependent manner (up to a 7-fold increase, p<0.0001). Uric acid up-regulated Bax (+60% with respect to Ctrl; p<0.05) and down regulated X-linked inhibitor of apoptosis protein. Apoptosis was blunted by Caspase-9 but not Caspase-8 inhibition. Uric acid induced changes in the mitochondrial membrane, elevations in reactive oxygen species and a pronounced up-regulation of NOX 4 mRNA and protein (p<0.05). In addition, both reactive oxygen species production and apoptosis was prevented by the NADPH oxidase inhibitor DPI as well as by Nox 4 knockdown. URAT 1 transport inhibition by probenecid and losartan and its knock down by specific siRNA, blunted apoptosis, suggesting a URAT 1 dependent cell death. In summary, our data show that uric acid increases the permissiveness of proximal tubule kidney cells to apoptosis by triggering a pathway involving NADPH oxidase signalling and URAT 1 transport. These results might explain the chronic tubulointerstitial damage observed in hyperuricaemic states and suggest that uric acid transport in tubular cells is necessary for urate-induced effects. PMID:25514209

Verzola, Daniela; Ratto, Elena; Villaggio, Barbara; Parodi, Emanuele Luigi; Pontremoli, Roberto; Garibotto, Giacomo; Viazzi, Francesca

2014-01-01

207

Uric acid induces fat accumulation via generation of endoplasmic reticulum stress and SREBP-1c activation in hepatocytes.  

PubMed

Non-alcoholic fatty liver disease (NAFLD) is currently one of the most common types of chronic liver injury. Elevated serum uric acid is a strong predictor of the development of fatty liver as well as metabolic syndrome. Here we demonstrate that uric acid induces triglyceride accumulation by SREBP-1c activation via induction of endoplasmic reticulum (ER) stress in hepatocytes. Uric acid-induced ER stress resulted in an increase of glucose-regulated protein (GRP78/94), splicing of the X-box-binding protein-1 (XBP-1), the phosphorylation of protein kinase RNA-like ER kinase (PERK), and eukaryotic translation initiation factor-2? (eIF-2?) in cultured hepatocytes. Uric acid promoted hepatic lipogenesis through overexpression of the lipogenic enzyme, acetyl-CoA carboxylase 1 (ACC1), fatty acid synthase (FAS), and stearoyl-CoA desaturase 1 (SCD1) via activation of SREBP-1c, which was blocked by probenecid, an organic anion transport blocker in HepG2 cells and primary hepatocytes. A blocker of ER stress, tauroursodeoxycholic acid (TUDCA), and an inhibitor of SREBP-1c, metformin, blocked hepatic fat accumulation, suggesting that uric acid promoted fat synthesis in hepatocytes via ER stress-induced activation of SREBP-1c. Uric acid-induced activation of NADPH oxidase preceded ER stress, which further induced mitochondrial ROS production in hepatocytes. These studies provide new insights into the mechanisms by which uric acid stimulates fat accumulation in the liver. PMID:25111690

Choi, Yea-Jin; Shin, Hyun-Soo; Choi, Hack Sun; Park, Joo-Won; Jo, Inho; Oh, Eok-Soo; Lee, Kang-Yo; Lee, Byung-Hoon; Johnson, Richard J; Kang, Duk-Hee

2014-10-01

208

Determination of uric acid level by polyaniline and poly (allylamine): Based biosensor  

PubMed Central

The uric acid biosensor has been much developed by immobilizing uricase enzyme into the membrane of conductive polymer and the membrane of polyelectrolyte such as polyaniline (PANI) and poly (allylamine) (PAA) respectively. The purpose of this research was to create a new amperometric uric acid biosensor by immobilization of uricase in combination between PANI and PAA membranes. The working electrode was Pt plate (0.5 mm). The auxiliary and the reference electrode were Pt wire 0.4 mm and Ag/AgCl respectively. Uricase, uric acid, PAA, pyrrole and glutaraldehyde were supplied from Sigma. All other chemical was obtained from Merck. The biosensor was created by immobilizing of uricase by a glutaraldehyde crosslinking procedure on PANI composite film on the surface of a platinum electrode while the polyelectrolyte layer of PAA were prepared via layer-by-layer assembly on the electrode, functioning as H2O2-selective film. Standard of deviation, coefficient of variation (CV) and coefficient of correlation (r) analysis were used in this study. The biosensor had a good linearity with a correlation coefficient of 0.993 and it could be used up to 27 times with the CV value of 3.97%. The presence of other compounds such as glucose and ascorbic acid gave 1.3 ± 1.13% and 3.27 ± 2.29% respectively on the interference effect toward the current response of uric acid biosensor. The polymer combination of PANI and PAA can be used as a selective matrix of uric acid biosensor. PMID:24696812

Wathoni, Nasrul; Hasanah, Aliya Nur; Gozali, Dolih; Wahyuni, Yeni; Fauziah, Lia Layusa

2014-01-01

209

Uridine - an indicator of post-exercise uric acid concentration and blood pressure.  

PubMed

Studies have shown that uridine concentration in plasma may be an indicator of uric acid production in patients with gout. It has been also postulated that uridine takes part in blood pressure regulation. Since physical exercise is an effective tool in treatment and prevention of cardio-vascular diseases that are often accompanied by hyperuricemia and hypertension, it seemed advisable to attempt to evaluate the relationship between oxypurine concentrations (Hyp, Xan and UA) and that of Urd and BP after physical exercise in healthy subjects. Sixty healthy men (17.2+/-1.71 yr, BMI 23.2+/-2.31 kg m(-2), VO(2max) 54.7+/-6.48 ml kg(-1) min(-1)) took part in the study. The subjects performed a single maximal physical exercise on a bicycle ergometer. Blood for analyses was sampled three times: immediately before exercise, immediately after exercise, and in the 30th minute of rest. Concentrations of uridine and hypoxanthine, xanthine and uric acid were determined in whole blood using high-performance liquid chromatography. We have shown in this study that the maximal exercise-induced increase of uridine concentration correlates with the post-exercise increase of uric acid concentration and systolic blood pressure. The results of our study show a relationship between uridine concentration in blood and uric acid concentration and blood pressure. We have been the first to demonstrate that a maximal exercise-induced increase in uridine concentration is correlated with the post-exercise and recovery-continued increase of uric acid concentration in healthy subjects. Thus, it appears that uridine may be an indicator of post-exercise hyperuricemia and blood pressure. PMID:25470512

Dudzinska, W; Lubkowska, A; Dolegowska, B; Suska, M; Janiak, M

2014-12-01

210

Disposition of exogenous urea and effects of diet in rats.  

PubMed

Although breath test using 13C-labeled urea (CAS 57-13-6, UBT) is becoming popular for the diagnosis of Helicobacter pylori (H. pylori) infection, disposition of exogenously given urea is not fully understood. The purpose of the present study is to elucidate the disposition of exogenous urea and to consider its relation with the UBT safety and biobehavior of endogenous urea. With 14C-labeled urea ([14C]urea), the absorption, distribution, metabolism and excretion including that into breathed air after its administration in trace to large doses in rats were investigated. [14C]Urea was given to fasted and non-fasted rats through intravenous and oral routes. It was found that the disposition of exogenous [14C]urea behaves in a similar way as endogenous urea, and a sufficiently large capacity for disposing urea in rats was suggested from the linear pharmacokinetics within the wide dose range of [14C]urea (2-1000 mg/kg). The safety of urea in UBT was also revealed by consideration of its dose and human urea body pool. It was also suggested that diet stimulates both systemic (as observed after the intravenous dose) and pre-systemic (as with the oral route) decompositions of urea into carbon dioxide and ammonia, but does not affect the renal elimination and distribution pattern in rat tissues. The findings in this study provide us with the quantitative information concerning not only the safety and disposition of urea as a diagnostic agent, but also the biobehavior of endogenous urea in ureotelism. PMID:16618019

Nomura, Naruaki; Matsumoto, Satoshi; Nishimura, Yuka; Terauchi, Yoshiaki; Fujii, Toshihiko

2006-01-01

211

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

212

Characterization of urease from Sporosarcina ureae.  

PubMed

Alkaline stable (pH 7.75-12.5) urease from Sporosarcina ureae was purified over 400-fold by ion exchange and hydrophobic interaction chromatography. The cytoplasmic enzyme was remarkably active with a specific activity of greater than 9300 mumol urea degraded min-1 mg protein-1 at pH 7.5, where it has optimal activity. Although S. ureae is closely related to Bacillus pasteurii, known to possess a homopolymeric urease containing 1 nickel per subunit [M(r) = 65000], the S. ureae enzyme is comprised of three subunits [apparent M(r) = 63,100 (alpha), 14,500 (beta), and 8500 (gamma)] in an estimated alpha beta gamma 2 stoichiometry and contains 2.1 +/- 0.6 nickel ions per alpha beta gamma 2 unit as measured by atomic absorption spectrometry. Stationary phase cultures sometimes possessed low levels of urease activity, but the specific activity of cell extracts of partially purified urease preparations from such cultures could be elevated by heat treatment, dilution, or dialysis to values comparable to those observed in samples from exponentially grown cells. PMID:1510567

McCoy, D D; Cetin, A; Hausinger, R P

1992-01-01

213

Reproductive Factors and Serum Uric Acid Levels in Females from the General Population: The KORA F4 Study  

PubMed Central

Objective Hyperuricemia is associated with an increased risk of metabolic and cardiovascular diseases. There are pronounced sex differences in the levels of uric acid. It is largely unknown whether or not reproductive parameters which induce hormonal changes are responsible for this. We examined if there are associations between reproductive parameters and uric acid levels in a female population-based sample. Methods In this cross-sectional analysis, data of 1530 women aged 32 to 81 years participating in the KORA F4 study, conducted between 2006 and 2008 in Southern Germany were used. Reproductive parameters were obtained by standardized interviews. Uric acid levels were tested by the uricase method. The whole study sample and stratified in pre- and postmenopausal women was analyzed. Results Menopausal status and earlier age at menarche were associated with higher serum uric acid levels (age-adjusted: p-values 0.003, <0.001 respectively; after multivariable adjustment, including BMI: p-values 0.002, 0.036). A history of oral contraceptive use showed an association with uric acid levels only after multivariable adjustment (p-value 0.009). Hot flushes showed an association with uric acid levels only after age-adjustment (p-value 0.038), but lost significance after adding other confounders. Other reproductive factors, including parity, current or ever use of hormone replacement therapy, current use of oral contraceptives, hysterectomy, bilateral oophorectomy, or depressive mood related to menopausal transition were not associated with uric acid levels. Conclusions Postmenopausal status, earlier age at menarche and a history of oral contraceptive use were independently associated with higher serum uric acid concentrations in women from the general population. Further studies, especially longitudinal population-based studies investigating the relationship of female reproductive parameters with uric acid levels are necessary to confirm our findings. PMID:22427861

Stöckl, Doris; Döring, Angela; Thorand, Barbara; Heier, Margit; Belcredi, Petra; Meisinger, Christa

2012-01-01

214

76 FR 15339 - Solid Urea From Russia and Ukraine  

Federal Register 2010, 2011, 2012, 2013, 2014

...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

215

76 FR 77015 - Solid Urea From Russia and Ukraine  

Federal Register 2010, 2011, 2012, 2013, 2014

...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

216

75 FR 74746 - Solid Urea From Russia and Ukraine  

Federal Register 2010, 2011, 2012, 2013, 2014

...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

217

21 CFR 176.320 - Sodium nitrate-urea complex.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2009-04-01 true 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...

2010-04-01

218

Investigating the Hydrogen-Bonding Model of Urea Denaturation  

E-print Network

Investigating the Hydrogen-Bonding Model of Urea Denaturation Laura B. Sagle, Yanjie Zhang@mail.chem.tamu.edu Abstract: The direct binding mechanism for urea-based denaturation of proteins was tested-induced denaturation of proteins. Introduction Although urea was first shown to denature proteins in 1900

219

21 CFR 176.320 - Sodium nitrate-urea complex.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 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...

2011-04-01

220

MICROWAVE-ASSISTED PREPARATION OF CYCLIC UREAS FROM DIAMINES  

EPA Science Inventory

Rajender S. Varma* and Yong-Jin Kim Cyclic ureas are useful intermediates for a variety of pharmaceuticals and pesticides. One of the attractive approaches for the synthesis of cyclic ureas uses condensation of diamines with urea as a carbonyl source under dynamic evacuation. ...

221

Concentration levels of urea in swimming pool water and reactivity of chlorine with urea  

Microsoft Academic Search

This study investigated the reactivity of chlorine with urea which is the main nitrogen contaminant introduced into swimming pool water by bathers. In the first part of this study, analyses showed that the mean concentrations of urea and TOC determined from 50 samples of municipal swimming pool were equal to 18.0 ?M (s.d. 11.7) and 3.5 mg C L?1 (s.d. 1.6), respectively. The mean

Joseph De Laat; Wentao Feng; Diab Adams Freyfer; Florence Dossier-Berne

2011-01-01

222

Sensitive Specialization Analysis of Urea in Human Blood by Surface Acoustic Wave Urea Sensor System  

Microsoft Academic Search

A novel and sensitive enzymatic method for the determination of micro amounts of urea in human blood has been developed based on the surface acoustic wave (SAW) urea sensor system, which was prepared by combining a SAW device with urease (E.C. 3.5.1.5) extracted directly from watermelon seeds. The Michaelis constant and maximum rate of the urease were estimated as 1.77

Liu Dezhong; Ge Kai; Chen Kang; Nie Lihua; Yao Shouzhuo

1996-01-01

223

HEMATOLOGY AND SERUM CHEMISTRY OF COTTONTAIL RABBITS OF SOUTHERN ILLINOIS  

Microsoft Academic Search

In 1983 and 1984 blood was collected from 79 cottontail rabbits (Sylvilagus floridanus) confined to an outdoor enclosure in southern Illinois to establish reference values for hematology and serum chemistry. Packed cell volume, sodium, potassium, chloride, g!ucose, calcium, carbon dioxide, blood urea nitrogen, creatinine, uric acid, cholesterol, albumin, bilirubin, alkaline phos- phatase, aspartate transaminase, alanine aminotransaminase, total protein, albumin\\/globulin ratio,

Dwayne A. W. Lepitzki; Alan Woolf

224

Urea transformation and the adaptability of three leafy vegetables to urea as a source of nitrogen in hydroponic culture  

Microsoft Academic Search

Substitution of urea for commonly used nitrate fertilizers in hydroponic culture of vegetables would not only avoid excessive accumulation of nitrate in plants but would also reduce the cost of production. This substitution, however, might have adverse effects, such as a dramatic decrease in solution pH, reduced nutrient uptake and possibly urea toxicity per se. Differences in adaptability to urea

Jian Luo; Zhaohuang Lian; Xiaolong Yan

1993-01-01

225

Preliminary Findings of Serum Creatinine and Estimated Glomerular Filtration Rate (eGFR) in Adolescents with Intellectual Disabilities  

ERIC Educational Resources Information Center

The present study aimed to describe the kidney function profile--serum creatinine and estimated glomerular filtration rate (eGFR), and to examine the relationships of predisposing factors to abnormal serum creatinine in people with intellectual disabilities (ID). Data were collected by a cross-sectional study of 827 aged 15-18 years adolescents…

Lin, Jin-Ding; Lin, Lan-Ping; Hsieh, Molly; Lin, Pei-Ying

2010-01-01

226

Direct Determination of Urinary Creatinine by Reactive-Thermal Desorption-Extractive Electrospray-Ion Mobility-Tandem Mass Spectrometry.  

PubMed Central

A direct, ambient ionization method has been developed for the determination of creatinine in urine that combines derivatization and thermal desorption with extractive electrospray ionization and ion mobility-mass spectrometry. The volatility of creatinine was enhanced by a rapid on-probe aqueous acylation reaction, using a custom-made thermal desorption probe, allowing thermal desorption and ionization of the monoacylated derivative. The monoacyl creatinine [M + H]+ ion (m/z 156) was subjected to mass-to-charge selection and collision induced dissociation to remove the acyl group, generating the protonated creatinine [M + H]+ product ion at m/z 114 before an ion mobility separation was applied to reduce chemical noise. Stable isotope dilution using creatinine-d3 as internal standard was used for quantitative measurements. The direct on-probe derivatization allows high sample throughput with a typical cycle time of 1 min per sample. The method shows good linearity (R2 = 0.986) and repeatability (%RSD 8–10%) in the range of 0.25–2.0 mg/mL. The creatinine concentrations in diluted urine samples from a healthy individual were determined to contain a mean concentration of 1.44 mg/mL creatinine with a precision (%RSD) of 9.9%. The reactive ambient ionization approach demonstrated here has potential for the determination of involatile analytes in urine and other biofluids. PMID:24279641

2013-01-01

227

Beating the system: a study of a creatinine assay and its efficacy in authenticating human urine specimens.  

PubMed

Creatinine concentration is commonly used to verify the authenticity of urine specimens submitted for illicit drug screening. This study evaluated creatinine screening of donor urine specimens as a tool for detecting substituted and/or tampered specimens. The study carried out creatinine assay of animal urine, fruit juices, and urine from creatine-supplemented subjects by a modified version of the Jaffe reaction. All specimens were analyzed for creatinine concentration in a chemistry-immuno analyzer. Results showed that urine specimens from common domestic pets, including cats, dogs, and horses, have creatinine values similar to normal human values. Most fruit juices tested contained no detectable creatinine, and the few that did showed poor "urine" chemical integrity. Creatine supplementation by donors was found not to provide an effective means of elevating creatinine concentration in urine when attempting to flush out water-soluble drugs in the body. Thus, the assay for creatinine proved useful for the detection of some but not all adulterated urine specimens. PMID:20109301

Villena, Vincent P

2010-01-01

228

Isolation of a novel uric-acid-degrading microbe Comamonas sp. BT UA and rapid biosensing of uric acid from extracted uricase enzyme.  

PubMed

Uric-acid-utilizing soil bacteria were isolated, and 16s rRNA sequence was studied for strain identification. The most prominent uricase-producing bacterium was identified as Comamonas sp BT UA. Crude enzyme was extracted, freeze-dried and its Km and Vmax were determined as 40 meu M and 0.047 meu M min-1ml-1 using Line-weaver Burke plot. An activity of 80 U/mg of total protein was observed when cultured at 37 degree C for 84 h at pH 7. The purified enzyme was used to measure uric acid by spectrophotometric method and electrochemical biosensor. In the biosensing system the enzyme was immobilized on the platinum electrode with a biodegradable glutaraldehyde-crosslinked gelatin film having a swelling percentage of 109+/- 3.08, and response was observed by amperometry applying fixed potential. The electrochemical process as obtained by the anodic peak current and scan rate relationship was further configured by electrochemical impedance spectroscopy (EIS). The polymer matrix on the working electrode gave capacitive response for the electrode-electrolyte interaction. The sensitivity of the biosensor was measured as 6.93 meu A meu M -1 with a sensor affinity [Km(app)] of 50 mu M and 95 percent reproducibility after 50 measurements. The spectrophotometric method could be used in the range of 6-1000 mu M, whereas the biosensor generated linear response in the 1.5- 1000 mu M range with a response time of 24 s and limit of detection of 0.56 meu M. Uric acid was estimated in human blood samples by the biosensor and satisfactory results were obtained. PMID:25431410

Ghosh, Tanushree; Sarkar, Priyabrata

2014-12-01

229

Uric Acid: A Danger Signal From the RNA World That May Have a Role in the Epidemic of Obesity, Metabolic  

E-print Network

that are less regulatable and can be readily influenced by diet. This increases our risk for gout and kidney levels are at increased risk for de- veloping gout and uric acid kidney stones. More impor- tantly

Gaucher, Eric

230

Urea-induced denaturation of PreQ1-riboswitch  

E-print Network

Urea, a polar molecule with a large dipole moment, not only destabilizes the folded RNA structures, but can also enhance the folding rates of large ribozymes. Unlike the mechanism of urea-induced unfolding of proteins, which is well understood, the action of urea on RNA has barely been explored. We performed extensive all atom molecular dynamics (MD) simulations to determine the molecular underpinnings of urea-induced RNA denaturation. Urea displays its denaturing power in both secondary and tertiary motifs of the riboswitch (RS) structure. Our simulations reveal that the denaturation of RNA structures is mainly driven by the hydrogen bonds and stacking interactions of urea with the bases. Through detailed studies of the simulation trajectories, we found that geminate pairs between urea and bases due to hydrogen bonds and stacks persist only ~ (0.1-1) ns, which suggests that urea-base interaction is highly dynamic. Most importantly, the early stage of base pair disruption is triggered by penetration of water molecules into the hydrophobic domain between the RNA bases. The infiltration of water into the narrow space between base pairs is critical in increasing the accessibility of urea to transiently disrupted bases, thus allowing urea to displace inter base hydrogen bonds. This mechanism, water-induced disruption of base-pairs resulting in the formation of a "wet" destabilized RNA followed by solvation by urea, is the exact opposite of the two-stage denaturation of proteins by urea. In the latter case, initial urea penetration creates a dry-globule, which is subsequently solvated by water penetration leading to global protein unfolding. Our work shows that the ability to interact with both water and polar, non-polar components of nucleotides makes urea a powerful chemical denaturant for nucleic acids.

Jeseong Yoon; D. Thirumalai; Changbong Hyeon

2013-07-20

231

Small-Molecule Inhibitors of Urea Transporters  

PubMed Central

Urea transporter (UT) proteins, which include isoforms of UT-A in kidney tubule epithelia and UT-B in vasa recta endothelia and erythrocytes, facilitate urinary concentrating function. Inhibitors of urea transporter function have potential clinical applications as sodium-sparing diuretics, or ‘urearetics,’ in edema from different etiologies, such as congestive heart failure and cirrhosis, as well as in syndrome of inappropriate antidiuretic hormone (SIADH). High-throughput screening of drug-like small molecules has identified UT-A and UT-B inhibitors with nanomolar potency. Inhibitors have been identified with different UT-A versus UT-B selectivity profiles and putative binding sites on UT proteins. Studies in rodent models support the utility of UT inhibitors in reducing urinary concentration, though testing in clinically relevant animal models of edema has not yet been done. PMID:25298345

Verkman, Alan S.; Esteva-Font, Cristina; Cil, Onur; Anderson, Marc O.; Li, Fei; Li, Min; Lei, Tianluo; Ren, Huiwen; Yang, Baoxue

2015-01-01

232

Determination of serum creatinine by reaction with methyl-3,5-dinitrobenzoate in Methyl Sulfoxide.  

PubMed

Creatinine in serum is determined with a new reagent system consisting of methyl-3,5-dinitrobenzoate and tetramethyl ammonium hydroxide in 50% methyl sulfoxide. The method shows excellent correlation with manual and automated alkaline picrate procedures and has comparable sensitivity. The proposed method has advantages over the dinitrobenzoyl chloride assay system in terms of sensitivity, reagent stability and precision. The day-to-day coefficient of variation is 2.9-3.8%, while within day is 1.5-2.1%. The standard curve is linear beyond 20 mg/dl creatinine. Compared to the picrate method, the proposed assay is less than one half as susceptible to a combination of known interfering agents. Based on the present studies, it is recommended as an excellent alternative to the commonly used picrate procedures. PMID:20028

Sims, C; Parekh, A C

1977-07-01

233

A reciprocal graph to plot the reciprocal serum creatinine over time.  

PubMed

In patients who have a linear decline in renal function over time, plotting the reciprocal serum creatinine versus time has been found to be useful in monitoring renal disease progression and predicting the start of dialysis. Unfortunately, producing such plots is cumbersome because of the inherent difficulties of plotting a reciprocal number on standard graph paper. This technical note presents a graph in which the y-axis is represented as a reciprocal axis. In this manner, one is able to directly plot the serum creatinine over time and must not rely on plotting the reciprocal value. This approach may make the plotting of such data easier for the nephrologist and make this clinical tool more useful. PMID:10469872

Bleyer, A J

1999-09-01

234

Genes and proteins of urea transporters.  

PubMed

A urea transporter protein in the kidney was first proposed in 1987. The first urea transporter cDNA was cloned in 1993. The SLC14a urea transporter family contains two major subgroups: SLC14a1, the UT-B urea transporter originally isolated from erythrocytes; and SLC14a2, the UT-A group originally isolated from kidney inner medulla. Slc14a1, the human UT-B gene, arises from a single locus located on chromosome 18q12.1-q21.1, which is located close to Slc14a2. Slc14a1 includes 11 exons, with the coding region extending from exon 4 to exon 11, and is approximately 30 kb in length. The Slc14a2 gene is a very large gene with 24 exons, is approximately 300 kb in length, and encodes 6 different isoforms. Slc14a2 contains two promoter elements: promoter I is located in the typical position, upstream of exon 1, and drives the transcription of UT-A1, UT-A1b, UT-A3, UT-A3b, and UT-A4; while promoter II is located within intron 12 and drives the transcription of UT-A2 and UT-A2b. UT-A1 and UT-A3 are located in the inner medullary collecting duct, UT-A2 in the thin descending limb and liver, UT-A5 in testis, UT-A6 in colon, UT-B1 primarily in descending vasa recta and erythrocytes, and UT-B2 in rumen. PMID:25298338

Sands, Jeff M; Blount, Mitsi A

2014-01-01

235

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

236

A longitudinal study of urea cycle disorders.  

PubMed

The Urea Cycle Disorders Consortium (UCDC) is a member of the NIH funded Rare Diseases Clinical Research Network and is performing a longitudinal study of 8 urea cycle disorders (UCDs) with initial enrollment beginning in 2006. The consortium consists of 14 sites in the U.S., Canada and Europe. This report summarizes data mining studies of 614 patients with UCDs enrolled in the UCDC's longitudinal study protocol. The most common disorder is ornithine transcarbamylase deficiency, accounting for more than half of the participants. We calculated the overall prevalence of urea cycle disorders to be 1/35,000, with 2/3rds presenting initial symptoms after the newborn period. We found the mortality rate to be 24% in neonatal onset cases and 11% in late onset cases. The most common precipitant of clinical hyperammonemic episodes in the post-neonatal period was intercurrent infections. Elevations in both blood ammonia and glutamine appeared to be biomarkers for neurocognitive outcome. In terms of chronic treatment, low protein diet appeared to result in normal weight but decreased linear growth while N-scavenger therapy with phenylbutyrate resulted in low levels of branched chain amino acids. Finally, we found an unexpectedly high risk for hepatic dysfunction in patients with ornithine transcarbamylase deficiency. This natural history study illustrates how a collaborative study of a rare genetic disorder can result in an improved understanding of morbidity and disease outcome. PMID:25135652

Batshaw, Mark L; Tuchman, Mendel; Summar, Marshall; Seminara, Jennifer

2014-01-01

237

A monitoring of allantoin, uric acid, and malondialdehyde levels in plasma and erythrocytes after ten minutes of running activity.  

PubMed

Uric acid is the final product of human purine metabolism. It was pointed out that this compound acts as an antioxidant and is able to react with reactive oxygen species forming allantoin. Therefore, the measurement of allantoin levels may be used for the determination of oxidative stress in humans. The aim of the study was to clarify the antioxidant effect of uric acid during intense exercise. Whole blood samples were obtained from a group of healthy subjects. Allantoin, uric acid, and malondialdehyde levels in plasma and erythrocytes were measured using a HPLC with UV/Vis detection. Statistical significant differences in allantoin and uric acid levels during short-term intense exercise were found. Immediately after intense exercise, the plasma allantoin levels increased on the average of 200 % in comparison to baseline. Plasma uric acid levels increased slowly, at an average of 20 %. On the other hand, there were no significant changes in plasma malondialdehyde. The results suggest that uric acid, important antioxidant, is probably oxidized by reactive oxygen species to allantoin. Therefore allantoin may be suitable candidate for a marker of acute oxidative stress. PMID:25157658

Kan?ár, R; Štramová, X; Drábková, P; K?enková, J

2014-12-23

238

Association between Serum Uric Acid Levels and Sleep Variables: Results from the National Health and Nutrition Survey 2005–2008  

PubMed Central

Sleep disordered breathing as well as high serum uric acid levels are independent risk factors for cardiovascular disease. However, studies evaluating the relationship between sleep-disordered breathing and hyperuricemia are limited. We examined the 2005–2008 National Health and Nutrition Examination survey's sleep variables and high serum uric acid among 6491 participants aged ?20 years. The sleep variables included sleep duration, snoring, snorting, and daytime sleepiness. The main outcome was high serum uric acid level, defined as levels of serum uric acid >6.8?mg/dL in males and >6.0?mg/dL in females. We found that snoring more than 5 nights per week, daytime sleepiness, and an additive composite score of sleep variables were associated with high serum uric acid in the age- , sex-adjusted model and in a multivariable model adjusting for demographic and lifestyle/behavioral risk factors. The association was attenuated with the addition of variables related to clinical outcomes such as depression, diabetes, hypertension, and high-cholesterol levels. Our results indicate a positive relationship between sleep variables, including the presence of snoring, snorting, and daytime sleepiness, and high serum uric acid levels. PMID:22970407

Wiener, R. Constance; Shankar, Anoop

2012-01-01

239

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

240

?2?Microglobulin, Cystatin C, and Creatinine and Risk of Symptomatic Peripheral Artery Disease  

PubMed Central

Background ?2?Microglobulin and cystatin C may have advantages over creatinine in assessing risk associated with kidney function. We therefore investigated whether emerging filtration markers, ?2?microglobulin and cystatin C, are prospectively associated with risk of the development of peripheral artery disease (PAD). Methods and Results We conducted nested case?control studies among women within the Nurses’ Health Study (1990–2010) and among men within the Health Professionals Follow?up Study (1994–2008) with the use of archived blood samples collected before PAD diagnosis. During follow?up, symptomatic PAD was confirmed in 144 women and 143 men. Controls were matched 3:1 based on age, race, smoking status, fasting status, and date of blood sampling. Conditional logistic regression models were used to estimate relative risks (RRs) and were adjusted for plasma creatinine and cardiovascular risk factors. In women, the RRs (95% CI) per 1?SD) increment were 1.16 (0.85 to 1.58) for ?2?microglobulin and 0.94 (0.69 to 1.28) for cystatin C. Corresponding RRs in men were 1.50 (1.08 to 2.09) for ?2?microglobulin and 1.54 (1.07 to 2.22) for cystatin C. There was no association between creatinine and PAD risk in women, whereas the association in men (RR 1.41, 95% CI 1.10 to 1.81) disappeared after adjustment for either ?2?microglobulin or cystatin C. In pooled analyses of men and women, only ?2?microglobulin was associated with PAD risk (RR 1.31, 95% CI 1.04 to 1.64). Conclusions In pooled analyses, ?2?microglobulin was associated with an increased risk of symptomatic PAD; a similar association with cystatin C was observed only in men. The findings suggest that ?2?microglobulin may capture the atherosclerosis?promoting or atherosclerosis?related elements of kidney dysfunction better than creatinine. PMID:24980133

Joosten, Michel M.; Pai, Jennifer K.; Bertoia, Monica L.; Gansevoort, Ron T.; Bakker, Stephan J. L.; Cooke, John P.; Rimm, Eric B.; Mukamal, Kenneth J.

2014-01-01

241

Simultaneous determination of uric acid and ascorbic acid using glassy carbon electrodes in acetate buffer solution  

Microsoft Academic Search

The present work reports the simultaneous determination of uric acid (UA) and ascorbic acid (AA) in 0.2M, pH 4.0, acetate buffer solution using glassy carbon (GC) electrode by square wave voltammetry. Selective detection of UA in the presence of 200-fold excess of AA is achieved at the GC electrode in acetate buffer solution. The GC electrode separates the voltammetric signal

S. Abraham John

2005-01-01

242

Preliminary investigations on a new disposable potentiometric biosensor for uric acid  

Microsoft Academic Search

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

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

2006-01-01

243

Detection of serum uric acid using the optical polymeric enzyme biochip system  

Microsoft Academic Search

An optical polymeric biochip system based on the complementary metal oxide semiconductor (CMOS) photo array sensor and polymeric enzyme biochip for rapidly quantitating uric acid in a one-step procedure was developed. The CMOS sensor was designed with N+\\/P-well structure and manufactured using a standard 0.5?m CMOS process. The polymeric enzyme biochip was immobilized with uricase–peroxidase and used to fill the

Su-Hua Huang; Yu-Chuan Shih; Chung-Yu Wu; Chiun-Jye Yuan; Yuh-Shyong Yang; Yaw-Kuen Li; Tung-Kung Wu

2004-01-01

244

Capillary electrophoresis with contactless conductivity detection for uric acid determination in biological fluids  

Microsoft Academic Search

The suitability of capillary electrophoresis (CE) with capacitively coupled contactless conductivity detection (C4D) for the direct determination of uric acid in human plasma and urine was investigated. It was found that a careful optimization of the buffer composition and pH was necessary to achieve selective determination in the complex sample matrices. An electrolyte solution consisting of 10mM 2-morpholinoethanesulfonic acid (MES),

Worapan Pormsila; Stephan Krähenbühl; Peter C. Hauser

2009-01-01

245

Paradoxical increase in uric acid level with allopurinol use in pyrazinamide-induced hyperuricaemia.  

PubMed

We report the case of a 36-year-old man with psoriatic arthritis and miliary tuberculosis, whose serum uric acid (SUA) level increased after the initiation of antituberculosis treatment, which included pyrazinamide. Most strikingly and paradoxically, the patient's SUA level increased after treatment with allopurinol. On cessation of allopurinol, his SUA level decreased substantially, and complete normalisation was observed following the discontinuation of pyrazinamide treatment. PMID:23677428

Gerdan, Vedat; Akkoc, Nurullah; Ucan, Eyup Sabri; Bulac Kir, Serpil

2013-06-01

246

Role of elevated serum uric acid levels at the onset of overt nephropathy in the risk for renal function decline in patients with type 2 diabetes  

PubMed Central

Aims/Introduction Despite the use of intensive therapies, declining renal function is often observed during the overt nephropathy stage of type 2 diabetes. We aimed at investigating the role of serum uric acid (SUA) levels at the onset of overt nephropathy in the risk of renal function decline in type 2 diabetes patients. Materials and Methods The present cohort study included 290 type 2 diabetes patients who were followed from the onset of overt nephropathy. The relationship between SUA and declining renal function was assessed using Cox regression models after adjusting for known risk factors. Results Over a median 4.8-year follow-up period, 85 patients (4.9/100 person-years) showed serum creatinine (Cr) doubling with a total cumulative incidence of 71.9% at 20 years of follow up. The highest SUA tertile resulted in significantly a higher incidence (7.7/100 person-years) and cumulative incidence at 20 years (85.7%) than the middle (3.9/100 person-years, 54.2%) and lowest (3.0/100 person-years, 55.5%) tertiles. The univariate Cox hazard model resulted in significant risks for Cr doubling related to female sex, short diabetes duration, smoking and elevated levels of low-density lipoprotein cholesterol (LDL-c), glycated hemoglobin and SUA tertiles. SUA tertiles remained statistically significant in the multivariate model (highest vs lowest hazard ratio 2.68, 95% confidence interval 1.48?5.00, P = 0.0009). Conclusions Elevated SUA levels within the normal range (men >6.3 mg/dL, women >5.1) at the onset of overt nephropathy resulted in an increased risk for declining renal function in type 2 diabetes patients.

Tanaka, Kentaro; Hara, Shigeko; Hattori, Masakazu; Sakai, Ken; Onishi, Yukiko; Yoshida, Yoko; Kawazu, Shoji; Kushiyama, Akifumi

2015-01-01

247

Blood pressure and creatinine clearance in lead-exposed children: the effect of treatment  

SciTech Connect

The authors speculated that normal growth might cause the release of stored lead in children, providing an endogenous source of exposure for years after the acute toxic episode had resolved. The purpose of this study was to answer the following two questions: (1) is a chelation-responsive lead burden present 2 to 5 yr after therapy for acute poisoning; and (2) does blood pressure or creatinine clearance correlate with body lead burden, as demonstrated by chelation. Thirty-eight children who had undergone ethylene diamine tetraacetic acid mobilization testing at least one time during the course of treatment in a lead clinic returned for follow-up care within 2-5 yr. All were asymptomatic. To determine the current level of body lead burden, a single-dose oral chelation with penicillamine was performed. Blood pressure and creatinine clearences were measured. From the data obtained for each child, we generated a geometric ''area'' representing the magnitude of lead burden integrated over the length of carriage of this burden. Multiple regression analysis indicated that after adjustment for the background variables of age, sex, height, and weight, none of the three parameters-mobilization ratio ''area,'' blood lead level, or FEP level-was a significant contributor to the variation observed in the blood pressures or creatinine clearances of the 38 lead-exposed children (P>.05).

Friedlander, M.A. (Univ. of Iowa Hospitals and Clinics, Iowa City); Brooks, C.T.; Sheehe, P.R.

1981-01-01

248

Exposure assessment approach through mycotoxin/creatinine ratio evaluation in urine by GC-MS/MS.  

PubMed

In this pilot survey human urine samples were analyzed for presence of 15 mycotoxins and some of their metabolites using a novel urinary multi-mycotoxin GC-MS/MS method following salting-out liquid-liquid extraction. Fifty-four urine samples from children and adults residents in Valencia were analyzed for presence of urinary mycotoxin and expressed in gram of creatinine. Three out of 15 mycotoxins were detected namely, HT-2 toxin, nivalenol and deoxynivalenol (DON). 37 samples showed quantifiable values of mycotoxins. Co-occurrence of these contaminants was also observed in 20.4% of assayed samples. DON was the most frequently detected mycotoxin (68.5%) with mean levels of 23.3 ?g/g creatinine (range: 2.8-69.1 ?g/g creatinine). The levels of urinary DON were used to carry out an exposure assessment approach. 8.1% of total subjects were estimated to exceed the DON provisional maximum tolerable daily intake (PMTDI) (1 ?g/kg b.w.). Two out of 9 exposed children exceeded the DON PMTDI thus, making them the most exposed based on the urinary results. PMID:25042512

Rodríguez-Carrasco, Yelko; Moltó, Juan Carlos; Mañes, Jordi; Berrada, Houda

2014-10-01

249

Serum uric acid levels and different phases of illness in bipolar I patients treated with lithium.  

PubMed

Recent findings support the role of purinergic system dysfunction in the pathophysiology of bipolar disorder (BD). The present study aimed to evaluate the pattern of serum uric acid levels in a sample of 98 BD I patients followed-up prospectively in a naturalistic study and treated with lithium monotherapy or in association with other mood stabilizers (valproate or carbamazepine), in relation to different phases of illness and to pharmacological treatment. The results showed that uric acid levels were significantly higher in patients suffering from a manic/mixed episode, than in those euthymic or during a depressive phase. Further, these levels were related to the Clinical Global Impression-Bipolar Version (CGI-BP) scale score for the severity of manic symptoms. A positive correlation was found also with male sex and with serum lithium levels. These findings suggest that a dysregulation of the purinergic system may occur during manic/mixed episodes, and they support a possible role of serum uric acid levels as a state-dependent marker of BD manic phases. PMID:25547850

Muti, Matteo; Del Grande, Claudia; Musetti, Laura; Marazziti, Donatella; Turri, Milo; Cirronis, Marco; Pergentini, Irene; Corsi, Martina; Dell'Osso, Liliana; Corsini, Giovanni Umberto

2015-02-28

250

Complement C5a potentiates uric acid crystal-induced IL-1? production.  

PubMed

Anaphylatoxin C5a released upon complement activation is associated with both acute and chronic inflammations such as gout. The pathogenesis of gout was identified as uric acid crystal deposition in the joints that activates inflammasome, leading to IL-1? release. However, little is known about the interaction between complement activation and monosodium urate/uric acid (MSU) crystal-induced inflammasome activation or IL-1? production. Here, we report that MSU crystal-induced proinflammatory cytokines/chemokines in human whole blood is predominantly regulated by C5a through its interaction with C5a receptor. C5a induces pro-IL-1? and IL-1? production in human primary monocytes, and potentiates MSU or cholesterol crystals in IL-1? production. This potentiation is caspase-1 dependent and requires intracellular Ca(2+) mobilization, K(+) efflux, and cathepsin B activity. Our results provide insight into the role of C5a as an endogenous priming signal that is required for the initiation of uric acid crystal-induced IL-1? production. C5a could potentially be a therapeutic target together with IL-1? antagonists for the treatment of complement-dependent and inflammasome-associated diseases. PMID:25229885

An, Ling-Ling; Mehta, Payal; Xu, Linda; Turman, Sean; Reimer, Thornik; Naiman, Brian; Connor, Jane; Sanjuan, Miguel; Kolbeck, Roland; Fung, Michael

2014-12-01

251

Correlation Between Hypertension, C-Reactive Protein and Serum Uric Acid With Psychological Well-being  

PubMed Central

Background: Multiple population-based human studies have established a strong association between increasing levels of serum C-reactive protein, uric acid and subsequent development of hypertension. Objectives: We aimed to investigate the association between mental well-being with presence of hypertension, hyperuricemia and hs-CRP levels. ?? Patients and Methods: This was a cross sectional study of 801 individuals aged 35-85 years old in Broujerd, Iran, included by randomized cluster sampling. General Health Questionnaire (GHQ-12) for assessing mental health/distress level, MONICA standard questions for evaluating hypertension history, serum hs-CRP and Serum Uric Acid (SUA) were evaluated Data were analyzed by appropriate statistical test such as chi-square, T-test and correlation. Results: One hundred eighty five patients (23.1%) had high distress/minor psychiatric disorders. SUA had significant association with hypertension (r = 0.64, P = 0.034). No significant relation was observed between hs-CRP and hypertension. The correlation between GHQ and hs-CRP was not significant but a weak and negative correlation was found between GHQ and SUA SUA (P = 0.012, r = -0.089). Conclusions: The weak and strong correlation among these parameters indicate that mental wellbeing relays on physical wellness and interact with each other; therefore, controlling hypertension along with uric acid control may effect mental health of any kind of patients. PMID:25237581

Maleki, Ali; Samandari, Saeid; Almeida, Osvaldo; Jafarian Kerman, Scott Reza; Abdolvand, Mahdi; Aliyari, Farshid; Foroughi, Saeid

2014-01-01

252

Comparison of Associations of Urine Protein-Creatinine Ratio Versus Albumin-Creatinine Ratio With Complications of CKD: A Cross-sectional Analysis  

PubMed Central

Background Urine albumin-creatinine ratio (ACR) and protein-creatinine ratio (PCR) are important markers of kidney damage and are utilized for prognosis in persons with chronic kidney disease (CKD). Despite how commonly these measurements are done in clinical practice, relatively few studies have directly compared the performance of these two measures with regard to associations with clinical outcomes, which may inform clinicians about which measure of urinary protein excretion is best. We studied the association of ACR and PCR with common complications of CKD. Study Design Cross-sectional study. Setting & Participants 3,481 participants with CKD in the Chronic Renal Insufficiency Cohort (CRIC) study. Predictors ACR and PCR. Outcomes We examined the association between ACR and PCR with measures of common CKD complications: serum hemoglobin, bicarbonate, parathyroid hormone, phosphorus, potassium and albumin. Measurements Restricted cubic spline analyses adjusted for estimated glomerular filtration rate (eGFR; calculated by the MDRD [Modification of Diet in Renal Disease] Study Equation) were performed to study the continuous association with our predictors with each outcome. Results Mean eGFR was 43 ± 13 (SD) ml/min/1.73 m2 and median levels of PCR and ACR were 140 and 46 mg/g, respectively. In continuous analyses adjusted for eGFR, higher ACR and PCR were comparable and both were associated with lower levels of serum hemoglobin, bicarbonate, and albumin and higher levels of parathyroid hormone, phosphorus, and potassium. Across all outcomes, the associations of ACR and PCR were comparable with only small, absolute differences in the outcome measure. Similar associations were seen in patients with diabetes mellitus. Limitations Participants largely had moderate CKD with low levels of ACR and PCR, so results may not be generalizable to all CKD populations. Conclusions In persons with CKD, ACR and PCR are relatively comparable in their associations with common complications of CKD. Thus routine measurement of PCR may provide similar information as ACR in managing immediate complications of CKD. PMID:24041612

Fisher, Herrick; Hsu, Chi-yuan; Vittinghoff, Eric; Lin, Feng; Bansal, Nisha

2013-01-01

253

Fasting Urinary Calcium-to-Creatinine and Oxalate-to-Creatinine Ratios in Dogs with Calcium Oxalate Urolithiasis and Breed-Matched Controls  

PubMed Central

Background Hypercalciuria and hyperoxaluria are risk factors for calcium oxalate (CaOx) urolithiasis, but breed-specific reports of urinary metabolites and their relationship with stone status are lacking. Objective To compare urinary metabolites (calcium and oxalate) and blood ionized calcium (iCa) concentrations between CaOx stone formers and breed-matched stone-free controls for the Miniature Schnauzer, Bichon Frise, and Shih Tzu breeds. Animals Forty-seven Miniature Schnauzers (23 cases and 24 controls), 27 Bichons Frise (14 cases and 13 controls), and 15 Shih Tzus (7 cases and 8 controls). Methods Prospective study. Fasting spot urinary calcium-to-creatinine and oxalate-to-creatinine ratios (UCa/Cr and UOx/Cr, respectively) and blood iCa concentrations were measured and compared between cases and controls within and across breeds. Regression models were used to test the effect of patient and environmental factors on these variables. Results UCa/Cr was higher in cases than controls for each of the 3 breeds. In addition to stone status, being on a therapeutic food designed to prevent CaOx stone recurrence was associated with higher UCa/Cr. UOx/Cr did not differ between cases and controls for any of the breeds. Blood iCa was higher in cases than controls in the Miniature Schnauzer and Bichon Frise breeds and had a moderate correlation with UCa/Cr. Conclusions and Clinical Importance Hypercalciuria is associated with CaOx stone status in the Miniature Schnauzer, Bichon Frise, and Shih Tzu breeds. UOx/Cr did not correlate with stone status in these 3 breeds. These findings may influence breed-specific stone prevention recommendations. PMID:25581880

Furrow, E.; Patterson, E.E.; Armstrong, P.J.; Osborne, C.A.; Lulich, J.P.

2015-01-01

254

Identification of a Proteinaceous Component in the Leaf of Moringa Oleifera lam. with Effects on High Serum Creatinine.  

PubMed

Moringa oleifera Lam. has been an important plant in the history of mankind, both for its nutritional and medicinal uses. Apart from bactericidal effects, the parts of this plant have been effectively used in the treatment of circulatory, respiratory, endocrine, digestive as well as neural disorders. Till date, though, there has been no reported activity of the involvement of any proteinaceous extract from M. oleifera on high levels of serum creatinine. To address this issue, blood samples with high levels of serum creatinine (2 mg/dl and above) were treated with leaf extract from M. oleifera. The crude extract was partially purified initially and eventually purified to completion as well. All these proteinaceous fractions were used to treat samples with high levels of serum creatinine as mentioned above. While the treatment of serum sample having high creatinine with crude extract and partially purified protein fractions showed a decrease of approximately 20% in the levels of serum creatinine over a period of 24 h, the samples treated with purified protein fraction reduced the serum creatinine level by 50%. In light of the fact that increased level of serum creatinine levels have adverse downstream effects on the heart, lungs and other organs, this communication assumes significance because it suggests a way of reducing the level of serum creatinine as an emergency measure. Further, the identification and characterisation of this proteinaceous component and possible in vivo experiments would provide a major tool for the treatment of downstream complications associated with increased serum creatinine via a new sources, albeit a natural one. PMID:24799742

Sahoo, S; Raghavendra, K M; Biswas, S

2014-01-01

255

Subchronic toxicity of croton oil (Croton tiglium L.) to sheep  

E-print Network

dehydrogenase; and serum levels of albumin, creatinine, glucose, inorganic phosphorus, total protein, urea nitrogen, and uric acid were determined by automated instrumental procedures. ' An atomic absorption spectrophotometer was k, l m used to determine.... Hematological and serum biochemical changes were most evident in higher dosages of croton with declines in levels of serum minerals and electrolytes (potassium, magnesium, sodium, copper) and albumin from control values. Blood urea nitrogen levels...

Harvey, Roger Bruce

2012-06-07

256

Uric Acid Stimulates Monocyte Chemoattractant Protein1 Production in Vascular Smooth Muscle Cells Via Mitogen-Activated Protein Kinase and Cyclooxygenase2  

Microsoft Academic Search

Previous studies have reported that uric acid stimulates vascular smooth muscle cell (VSMC) proliferation in vitro. We hypothesized that uric acid may also have direct proinflammatory effects on VSMCs. Crystal- and endotoxin-free uric acid was found to increase VSMC monocyte chemoattractant protein-1 (MCP-1) expression in a time- and dose-dependent manner, peaking at 24 hours. Increased mRNA and protein expression occurred

John Kanellis; Susumu Watanabe; Jin H. Li; Duk Hee Kang; Ping Li; Takahiko Nakagawa; Ann Wamsley; David Sheikh-Hamad; Hui Y. Lan; Lili Feng; Richard J. Johnson

2010-01-01

257

The electrophoresis of transferrins in urea/polyacrylamide gels.  

PubMed Central

The denaturation of transferrin by urea has been studied by (a) electrophoresis in polyacrylamide gels incorporating a urea gradient, (b) measurements of the loss of iron-binding capacity and (c) u.v. difference spectrometry. In human serum transferrin and hen ovotransferrin the N-terminal and C-terminal domains of the iron-free protein were found to denature at different urea concentrations. Images Fig. 1. Fig. 2. Fig. 3. Fig. 4. Fig. 7. PMID:7213345

Evans, R W; Williams, J

1980-01-01

258

14C-urea breath test in C pylori gastritis  

Microsoft Academic Search

14C-urea breath test was used to detect Campylobacter pylori colonisation in 129 consecutive non-ulcer dyspepsia patients. Fasting patients were given 3 microCi (110 kBq) of 14C-labelled urea after a test meal. Breath samples were collected at 10 minute intervals for 90 minutes and the C-14 activity was counted on a liquid scintillation analyser. Urea derived 14CO2 appears in the exhaled

E A Rauws; E A Royen; W Langenberg; J V Woensel; A A Vrij; G N Tytgat

1989-01-01

259

Common genetic variants of the human UMOD gene are functional on transcription and predict plasma uric acid in two distinct populations  

PubMed Central

Uromodulin (UMOD) genetic variants cause familial juvenile hyperuricemic nephropathy, characterized by hyperuricemia, decreased renal excretion of UMOD and uric acid; such findings suggest a role for UMOD in the regulation of plasma uric acid. We screened common variants across the UMOD locus in two populations, one from a community-based Chinese population, the other from California twins and siblings. Transcriptional activity of promoter variants was estimated in luciferase reporter plasmids transfected into HEK293 cells and mlMCD3 cells. By variance components in twin pairs, uric acid concentration and excretion were heritable traits. In the primary population from Beijing, we identified that carriers of haplotype GCC displayed higher plasma uric acid, and 3 UMOD promoter variants associated with plasma uric acid. UMOD promoter variants displayed reciprocal effects on urine uric acid excretion and plasma uric acid concentration, suggesting a primary effect on renal tubular handling of urate. These UMOD genetic marker-on-trait associations for uric acid were replicated in an independent American population sample. Site-directed mutagenesis at trait-associated UMOD promoter variants altered promoter activity in transfected luciferase reporter plasmids. These results suggest that UMOD promoter variants seem to initiate a cascade of transcriptional and biochemical changes influencing UMOD secretion, eventuating in elevation of plasma uric acid. PMID:23344472

Han, Jia; Liu, Ying; Rao, Fangwen; Nievergelt, Caroline M.; O’Connor, Daniel T.; Wang, Xingyu; Liu, Lisheng; Bu, Dingfang; Liang, Yu; Wang, Fang; Zhang, Luxia; Zhang, Hong; Chen, Yuqing; Wang, Haiyan

2013-01-01

260

Daily rhythm of salivary and serum urea concentration in sheep  

PubMed Central

Background In domestic animals many biochemical and physiological processes exhibit daily rhythmicity. The aim of the present study was to investigate the rhythmic pattern of salivary and serum urea concentrations in sheep. Methods Six 3-year-old female sheep kept in the same environmental conditions were used. Sheep were sampled at 4 hour intervals for 48 consecutive hours starting at 08:00 of the first day and finishing at 04:00 of the second day. Blood samples were collected via intravenous cannulae inserted into the jugular vein; saliva samples were collected through a specific tube, the "Salivette". Salivary and serum urea concentrations were assayed by means of UV spectrophotometer. ANOVA was used to determine significant differences. The single Cosinor procedure was applied to the results showing significant differences over time. Results ANOVA showed a significant effect of time on salivary and serum urea concentrations. Serum and salivary urea peaked during the light phase. In the dark phase serum and salivary urea concentrations decreased, and the diurnal trough occurred at midnight. Cosinor analysis showed diurnal acrophases for salivary and serum urea concentrations. Daily mean levels were significantly higher in the serum than in the saliva. Conclusion In sheep both salivary and serum urea concentrations showed daily fluctuations. Urea is synthesized in the liver and its production is strongly influenced by food intake. Future investigation should clarify whether daily urea rhythms in sheep are endogenous or are simply the result of the temporal administration of food. PMID:17123442

Piccione, Giuseppe; Foà, Augusto; Bertolucci, Cristiano; Caola, Giovanni

2006-01-01

261

Urea Impedes the Hydrophobic Collapse of Partially Unfolded Proteins  

PubMed Central

Proteins are denatured in aqueous urea solution. The nature of the molecular driving forces has received substantial attention in the past, whereas the question how urea acts at different phases of unfolding is not yet well understood at the atomic level. In particular, it is unclear whether urea actively attacks folded proteins or instead stabilizes unfolded conformations. Here we investigated the effect of urea at different phases of unfolding by molecular dynamics simulations, and the behavior of partially unfolded states in both aqueous urea solution and in pure water was compared. Whereas the partially unfolded protein in water exhibited hydrophobic collapses as primary refolding events, it remained stable or even underwent further unfolding steps in aqueous urea solution. Further, initial unfolding steps of the folded protein were found not to be triggered by urea, but instead, stabilized. The underlying mechanism of this stabilization is a favorable interaction of urea with transiently exposed, less-polar residues and the protein backbone, thereby impeding back-reactions. Taken together, these results suggest that, quite generally, urea-induced protein unfolding proceeds primarily not by active attack. Rather, thermal fluctuations toward the unfolded state are stabilized and the hydrophobic collapse of partially unfolded proteins toward the native state is impeded. As a result, the equilibrium is shifted toward the unfolded state. PMID:19413980

Stumpe, Martin C.; Grubmüller, Helmut

2009-01-01

262

Functional Nanomaterials from Bis-urea Macrocycles  

NASA Astrophysics Data System (ADS)

Self-assembly of bis-urea macrocycles usually give tubular crystals with nano-sized channels that we use as molecular container. These molecular containers alter the reactivity, stability, and chemical behavior of the reactants entrapped within them. This dissertation is focused on bulk synthesis, material characterization and applications of a self-assembled tubular molecular container. This crystalline straw-like container is developed from cyclic bis-urea macrocycles containing two C-shaped phenylethynylene units and two urea groups. These macrocycles afford a large open channel with a diameter of ˜9 A and it can accommodate larger solid guests such as coumarin and its methylated derivatives, stilbenes, acenaphthylene and styrenes. We developed the method to introduce these solid guests into the channel from its solution. We characterized the tubular host as well as different host*guest complexes by solid-state techniques including PXRD, CP MAS 13C NMR, fluorescence and UV-vis spectroscopy. These guests usually undergo non selective photoreaction in solid-state with very low percent conversion and produce different photodimers and/or isomers. Within our molecular container, a number of guests showed photo-dimerization with amazing selectivity and enhanced conversion in the solid-state. We also performed molecular modeling studies to find out the reason behind this unprecedented selectivity. We found the orientation of the guest molecules inside the channel as well as the stability of the photoproducts within the confinement determines the outcome of the reactions. We also developed a 5,5'-bipyridine containing bis-urea macrocycle and formed its complexes with metals. These complexes have potential to further assemble through dative bonds, hydrogen bonding and aryl stacking interactions to afford metal organic framework (MOF). We found the Ag complex forms oligomers and polymers. In the polymer structure it forms infinite chains comprised of "box" like unit cell. In one unit cell, two silver atoms are 3.13 A apart suggesting a very interesting Ag-Ag bond interaction. We probed the Ag-Ag interaction by solid-state spectroscopic techniques as well as ESI-MS and Raman spectroscopy. The results indicate that there is indeed an interaction between the two silver atoms and their proximity is not merely a packing artifact.

Dawn, Sandipan

263

Urea formaldehyde foam: a dangerous insulation  

SciTech Connect

Insulating a home with urea formaldehyde foam can lead to severe health problems due to poisoning from formaldehyde gas. Respiratory problems, allergies, memory loss, and mental problems can result from exposure to foam insulation fumes. Research is now under way at the Chemical Industry Inst., Univ. of Washington, and other institutions to learn more about the health effects of formaldehyde foam and to develop possible remedies to these problems. Several states are either banning or controlling the use of this type of home insulation.

Keough, C.

1980-12-01

264

Effect of organic matter and urease inhibitors on urea hydrolysis and immobilization of urea nitrogen in an alkaline soil  

Microsoft Academic Search

Laboratory incubation experiments with 15N-labelled urea were conducted on a Aquic Udifluvent Belgian soil amended with barley straw, in, order to study the influence of three urease inhibitors, hydroquinone, phenyl phosphorodiamidate and N-(n-butyl) phosphorothioic triamide on urea hydrolysis and N transformations. The results demonstrated that the urea was hydrolyzed more rapidly when the soil was amended with ground barley straw.

Wang Zhengping; O. Van Cleemput; Li Liantie; L. Baert

1991-01-01

265

Renal Drug Dosage Adjustment According to Estimated Creatinine Clearance in Hospitalized Patients With Heart Failure.  

PubMed

It is of clinical importance to determine creatinine clearance and adjust doses of prescribed drugs accordingly in patients with heart failure to prevent untoward effects. There is a scarcity of studies in the literature investigating this issue particularly in patients with heart failure, in whom many have impaired kidney function. The purpose of this study was to determine the degree of awareness of medication prescription as to creatinine clearance in patients hospitalized with heart failure. Patients hospitalized with a diagnosis of heart failure were retrospectively evaluated. Among screened charts, patients with left ventricular ejection fraction <40% and an estimated glomerular filtration rate (eGFR) of ?50 mL/min were included in the analysis. The medications and respective doses prescribed at discharge were recorded. Medications requiring renal dose adjustment were determined and evaluated for appropriate dosing according to eGFR. A total of 388 patients with concomitant heart failure and renal dysfunction were included in the study. The total number of prescribed medications was 2808 and 48.3% (1357 medications) required renal dose adjustment. Of the 1357 medications, 12.6% (171 medications) were found to be inappropriately prescribed according to eGFR. The most common inappropriately prescribed medications were famotidine, metformin, perindopril, and ramipril. A significant portion of medications used in heart failure requires dose adjustment. Our results showed that in a typical cohort of patients with heart failure, many drugs are prescribed at inappropriately high doses according to creatinine clearance. Awareness should be increased among physicians caring for patients with heart failure to prevent adverse events related to medications. PMID:24263162

Altunbas, Gokhan; Yazc, Mehmet; Solak, Yalcin; Gul, Enes E; Kayrak, Mehmet; Kaya, Zeynettin; Akilli, Hakan; Aribas, Alpay; Gaipov, Abduzhappar; Yazc, Raziye; Ozdemir, Kurtulus

2013-11-20

266

KEY COMPARISON: CCQM-K12: The determination of creatinine in serum  

NASA Astrophysics Data System (ADS)

A Key Comparison on the determination of creatinine in human serum organized by the Consultative Committee on Amount of Substance (CCQM) was carried out in 2001. To address the measurement traceability needs of the clinical chemistry community, the CCQM is undertaking Key Comparisons to document the capabilities of national metrology institutes (NMIs) that provide measurement services in this area. This Key Comparison, along with two others recently completed, CCQM-K6 and CCQM-K11, determination of total cholesterol and glucose, respectively, in serum, will provide a basis for evaluating the capabilities of NMIs for the determination of well-defined, organic substances of similar molecular weights and concentrations in human serum. Participants in CCQM-K12 included: National Institute of Standards and Technology (NIST) [USA], Coordinating Laboratory; Institute for Reference Materials and Measurements (IRMM) [EU]; Korea Research Institute of Standards and Science (KRISS) [S Korea]; Laboratory of the Government Chemist, (LGC) [UK]; and Physikalisch-Technische Bundesanstalt (PTB) [Germany]. Two frozen human serum materials were analyzed by each of the participants using either ID-GC/MS-based methods (three laboratories) or ID-LC/MS-based methods (two laboratories). Agreement of results among the participants was excellent, in accordance with the agreement found in a pilot study (CCQM-P9) for creatinine in serum. The resulting Key Comparison Reference Values had expanded uncertainties of less than 1% for both materials. In conclusion, five NMIs have demonstrated their ability to make reference measurements of creatinine in serum using isotope dilution-based methods that, when executed properly, provide measurements that are precise, accurate and SI traceable. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the Mutual Recognition Arrangement (MRA).

Welch, Michael J.; Phinney, Curtis P.; Parris, Reenie M.; May, Willie E.; Heo, Gwi Suk; Henrion, Andre; O'Conner, Gavin; Schimmel, Heinz

2003-01-01

267

Assessment of Density Functionals, Semiempirical Methods, and SCC-DFTB for Protonated Creatinine Geometries  

PubMed Central

Creatinine concentrations in blood and urine can be used to detect renal insufficiencies and muscle diseases, but current chemical sensors cannot measure creatinine with sufficient selectivity and robustness because they lack a receptor that binds protonated creatinine (creatininium) selectively enough. As a first step toward identifying potential receptors for creatininium, we examine the accuracy of density functional theory (DFT) and wave function theory (WFT) calculations for creatininium cation geometries, evaluated against reference parameters from experiment. We tested twenty-one local and nonlocal density functionals, Hartree-Fock theory, four semiempirical molecular orbital (SEMO) methods of the neglect of differential overlap (NDO) type, and one self-consistent-field nonorthogonal tight-binding method (SCC-DFTB) as implemented in two closely related software packages. DFT and HF calculations were carried out with the MG3S augmented polarized triple-zeta basis set. We find that DFT significantly outperforms SEMO methods for our dataset, and both SCC-DFTB releases we tested (which gave almost identical results) were less accurate than 81% of the density functionals evaluated. The top five functionals for the creatininium structures we examined were MPW1B95, PBEh, mPW1PW, SVWN5, and B97?2, with MMUEs in bond length of 0.0126 Å, 0.0129 Å, 0.0133 Å, 0.0142 Å, and 0.0144 Å respectively, which indicates that all five functionals are similarly suitable for creatininium. The popular B3LYP functional has a MMUE of 0.0178 Å, which ranks it 16th overall. B3LYP also performs less favorably than the best local functional (SVWN5), which is less expensive. PMID:19122761

Settergren, Nicole M.; Bühlmann, Philippe; Amin, Elizabeth A.

2008-01-01

268

Development of an isotope dilution GC-MS procedure for the routine determination of creatinine in complex serum samples.  

PubMed

The accurate determination of creatinine in serum is essential for the diagnosis and treatment of kidney diseases. The determination of serum creatinine in clinical laboratories is routinely carried out by the Jaffe method or by enzymatic methods that may suffer from interferences. So, the development of reliable, fast and interference-free routine methods for complex serum samples is required. A fast method using isotope dilution mass spectrometry (IDMS) and gas chromatography mass spectrometry (GC-MS) was developed using minimally (13)C labeled creatinine analogs, multiple linear regression and rapid derivatization of creatinine with acetylacetone in 2 min by using focused microwave technology. The proposed method was validated with the analyses of two Certified Reference Materials (ERM-DA252a and ERM-DA253a) and compared with the Jaffe and enzymatic methods when analyzing real serum samples containing variable levels of bilirubin The proposed method is capable of providing accurate serum creatinine concentrations in less than 45 min from sample arrival to full data treatment and can be an alternative routine procedure for creatinine determinations in complex serum samples. PMID:24508629

Fernández-Fernández, Mario; González-Antuña, Ana; Rodríguez-González, Pablo; Añón Álvarez, M Elena; Álvarez, Francisco V; García Alonso, J Ignacio

2014-04-20

269

Effect of urea and urea-gamma treatments on cellulose degradation of Thai rice straw and corn stalk  

NASA Astrophysics Data System (ADS)

Cellulose degradation of 20% urea treated and 20% urea-10 kGy gamma treated Thai rice straw and corn stalk showed that combination effect of urea and gamma radiation gave a higher % decrease in neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), cellulose, hemicellulose, and lignin and cutin in comparison with urea effect only for both room temperature storage and room temperature +258 K storage. The results also indicated that cellulose degradation proceeded with time, even at 258 K. A drastic drop to less than half of the original contents in NDF, ADF, and ADL could not be obtained in this study.

Banchorndhevakul, Siriwattana

2002-08-01

270

Soluble Ligand CD40 and Uric Acid as Markers of Atheromatosis in Patients with Obstructive Sleep Apnea.  

PubMed

The aim of the study was to evaluate the risk of atheromatosis in patients with obstructive sleep apnea (OSA), as based on the concentration of the pro-atherogenic soluble CD40L ligand (sCD40L) in relation to the level of uric acid. The serum levels of sCD40L and uric acid were measured in 79 OSA patients (mean apnea/hypopnea index - AHI 34.4?±?20.9) and in 40 healthy controls. We found that sCD40L was higher in the OSA patients with hyperuricemia than that in the patients with uric acid in the normal range (sCD40L: 9.0 ng/ml vs. 8.0 ng/ml, respectively, p?Uric acid correlated negatively with the mean and minimal SaO2 and positively with the oxygen desaturation index (p?uric acid concentration have increased risk of atheromatosis, as indicated by a higher level of soluble pro-atherogenic ligand CD40, and a higher prevalence of cardiovascular adverse events. PMID:25315617

Kosacka, M; Brzecka, A; Piesiak, P; Korzeniewska, A; Jankowska, R

2015-01-01

271

Lessons from comparative physiology: could uric acid represent a physiologic alarm signal gone awry in western society?  

PubMed Central

Uric acid has historically been viewed as a purine metabolic waste product excreted by the kidney and gut that is relatively unimportant other than its penchant to crystallize in joints to cause the disease gout. In recent years, however, there has been the realization that uric acid is not biologically inert but may have a wide range of actions, including being both a pro- and anti-oxidant, a neurostimulant, and an inducer of inflammation and activator of the innate immune response. In this paper, we present the hypothesis that uric acid has a key role in the foraging response associated with starvation and fasting. We further suggest that there is a complex interplay between fructose, uric acid and vitamin C, with fructose and uric acid stimulating the foraging response and vitamin C countering this response. Finally, we suggest that the mutations in ascorbate synthesis and uricase that characterized early primate evolution were likely in response to the need to stimulate the foraging “survival” response and might have inadvertently had a role in accelerating the development of bipedal locomotion and intellectual development. Unfortunately, due to marked changes in the diet, resulting in dramatic increases in fructose- and purine-rich foods, these identical genotypic changes may be largely responsible for the epidemic of obesity, diabetes and cardiovascular disease in today’s society. PMID:18649082

Sautin, Yuri Y.; Oliver, William J.; Roncal, Carlos; Mu, Wei; Sanchez-Lozada, L. Gabriela; Rodriguez-Iturbe, Bernardo; Nakagawa, Takahiko; Benner, Steven A.

2009-01-01

272

Quantitative detection of uric Acid by electrochemical-surface enhanced Raman spectroscopy using a multilayered au/ag substrate.  

PubMed

Uric acid is a potential important biomarker in urine and serum samples for early diagnosis of preeclampsia, a life-threatening hypertensive disorder that occurs during pregnancy. Preeclampsia is a leading cause of maternal death, especially in developing nation settings. Quantitative detection of uric acid for rapid and routine diagnosis of early preeclampsia using electrochemical-surface enhanced Raman spectroscopy (EC-SERS) is presented herein. A uniform EC-SERS active Au/Ag substrate was developed by depositing nearly monodisperse gold and silver nanoparticles on the carbon working electrode surface of screen printed electrodes. The multilayered Au/Ag substrates were characterized by electron microscopy and used for quantitative detection of uric acid in 0.1 M NaF and synthetic urine at clinically relevant concentrations. These results showed a linear relationship between the EC-SERS signal intensity and the uric acid concentration. Relative errors calculated for selected concentrations were all within the Clinical Laboratory Improvement Amendments (CLIA) criterion for uric acid analysis (±17%). It is believed that routine and early diagnosis of disease could be possible through such quantitative detection of biomarkers in patient samples using this EC-SERS method. PMID:25483146

Zhao, Lili; Blackburn, Jonathan; Brosseau, Christa L

2015-01-01

273

Effects of a fermented barley extract on subjects with slightly high serum uric acid or mild hyperuricemia.  

PubMed

The uric acid-lowering effect and safety of a fermented barley extract P (FBEP) prepared from barley-shochu distillery by-products were investigated in a randomized, placebo-controlled, parallel-group, double-blinded study. A total of 111 subjects with serum uric acid levels of 6.0-7.9 mg/dl were provided with either a drink containing 2 g/d of FBEP (test group) or a placebo drink. After 12 weeks, the serum uric acid levels changed by -0.21+/-0.56 mg/dl in the test group, showing a significant decrease in comparison to those of the placebo group (+0.02+/-0.54 mg/dl). Additionally, the uric acid clearance in the test group showed a tendency to increase after 12 weeks more than in the placebo group (p=0.054). No abnormalities in the physical and clinical tests were observed, and no adverse diagnostic findings were attributed to the intake of the test meal. These results demonstrated the benefits and safety of the FBEP treatment to subjects with slightly high serum uric acid or mild hyperuricemia. PMID:20378966

Hokazono, Hideki; Omori, Toshiro; Yamamoto, Tetsuro; Akaoka, Ieo; Ono, Kazuhisa

2010-01-01

274

Relationship between Serum Concentration of Uric Acid and Insulin Secretion among Adults with Type 2 Diabetes Mellitus  

PubMed Central

To determine the relationship between serum concentrations of uric acid and insulin secretion with hyperglycaemic clamp technique among adults with type 2 diabetes mellitus (DM2) without hyperuricemia, we carried out a cross-sectional study on 45 patients of both gender. We observed correlation between uric acid with male gender r = 0.710 (P = 0.001). Also correlation between uric acid and total insulin secretion was positive r = 0.295 (P = 0.049). As well as a positive correlation adjusted for body mass index was demonstrated for the first, second, and total phases of insulin secretion, respectively, r = 0.438 (P = 0.022), r = 0.433 (P = 0.022), and r = 0.439 (P = 0.024). Serum concentration of uric acid showed a positive relationship with the total phase of insulin secretion; even in states prior to hyperuricemia, uric acid can play an important role in the function of the beta cell in patients with DM2. PMID:22216028

Robles-Cervantes, J. A.; Ramos-Zavala, M. G.; González-Ortiz, M.; Martínez-Abundis, E.; Valencia-Sandoval, C.; Torres-Chávez, A.; Espinel-Bermúdez, C.; Santiago-Hernández, N. J.; Hernández-González, S. O.

2011-01-01

275

Activation of human fibroblast-like synoviocytes by uric acid crystals in rheumatoid arthritis  

PubMed Central

Hyperuricemia-mediated uric acid crystal formation may cause joint inflammation and provoke the destruction of joints through the activation of inflammasome-mediated innate immune responses. However, the immunopathological effects and underlying intracellular regulatory mechanisms of uric acid crystal-mediated activation of fibroblast-like synoviocytes (FLS) in rheumatoid arthritis (RA) have not been elucidated. Therefore, we investigated the in vitro effects of monosodium urate crystals, alone or in combination with the inflammatory cytokines tumor-necrosis factor (TNF)-? or interleukin (IL)-1?, on the activation of human FLS from RA patients and normal control subjects and the underlying intracellular signaling mechanisms of treatment with these crystals. Monosodium urate crystals were able to significantly increase the release of the inflammatory cytokine IL-6, the chemokine CXCL8 and the matrix metalloproteinase (MMP)-1 from both normal and RA-FLS (all P<0.05). Moreover, the additive or synergistic effect on the release of IL-6, CXCL8 and MMP-1 from both normal and RA-FLS was observed following the combined treatment with monosodium urate crystals and TNF-? or IL-1?. Further experiments showed that the release of the measured inflammatory cytokine, chemokine and MMP-1 stimulated by monosodium urate crystals were differentially regulated by the intracellular activation of extracellular signal-regulated kinase and c-Jun N-terminal kinase pathways but not the p38 mitogen-activated protein kinase pathway. Our results therefore provide a new insight into the uric acid crystal-activated immunopathological mechanisms mediated by distinct intracellular signal transduction pathways leading to joint inflammation in RA. PMID:21946433

Chen, Da P; Wong, Chun K; Tam, Lai S; Li, Edmund K; Lam, Christopher WK

2011-01-01

276

Glycosuria-mediated urinary uric acid excretion in patients with uncomplicated type 1 diabetes mellitus.  

PubMed

Plasma uric acid (PUA) is associated with metabolic, cardiovascular, and renal abnormalities in patients with type 2 diabetes but is less well understood in type 1 diabetes (T1D). Our aim was to compare PUA levels and fractional uric acid excretion (FEUA) in patients with T1D vs. healthy controls (HC) during euglycemia and hyperglycemia. PUA, FEUA, blood pressure (BP), glomerular filtration rate (GFR-inulin), and effective renal plasma flow (ERPF-paraaminohippurate) were evaluated in patients with T1D (n = 66) during clamped euglycemia (glucose 4-6 mmol/l) and hyperglycemia (9-11 mmol/l), and in HC (n = 41) during euglycemia. To separate the effects of hyperglycemia vs. increased glycosuria, parameters were evaluated during clamped euglycemia in a subset of T1D patients before and after sodium glucose cotransporter 2 (SGLT2) inhibition for 8 wk. PUA was lower in T1D vs. HC (228 ± 62 vs. 305 ± 75 ?mol/l, P < 0.0001). In T1D, hyperglycemia further decreased PUA (228 ± 62 to 199 ± 65 ?mol/l, P < 0.0001), which was accompanied by an increase in FEUA (7.3 ± 3.8 to 11.6 ± 6.7, P < 0.0001). In T1D, PUA levels correlated positively with SBP (P = 0.029) and negatively with ERPF (P = 0.031) and GFR (P = 0.028). After induction of glycosuria with SGLT2 inhibition while maintaining clamped euglycemia, PUA decreased (P < 0.0001) and FEUA increased (P < 0.0001). PUA is lower in T1D vs. HC and positively correlates with SBP and negatively with GFR and ERPF in T1D. Glycosuria rather than hyperglycemia increases uricosuria in T1D. Future studies examining the effect of uric acid-lowering therapies should account for the impact of ambient glycemia, which causes an important uricosuric effect. PMID:25377916

Lytvyn, Yuliya; Škrti?, Marko; Yang, Gary K; Yip, Paul M; Perkins, Bruce A; Cherney, David Z I

2015-01-15

277

[Dual energy x-ray absorptiometry: progress in the radiological identification of uric acid stones].  

PubMed

The prospect for a treatment by chemical lysis and the effective disease prevention appropriateness are the purposes of the early recognition of the uric acid stones, which counts up to 10% of all kidney stones. Until now, this characterization was possible only afterwards by the chemical analysis of an expelled stone. Neither biology nor radiology contributed as a valid share on this subject. CT with "dual energy" mode seems to fill this gap. This concept, known since the seventies, reaches the clinical routine now thanks for the use of a "dual source CT". PMID:18986626

Vandervaeren, D; Kirsch, J

2008-10-01

278

40 CFR 721.9920 - Urea, (hexahydro-6-methyl-2-oxopyrimidinyl)-.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Urea, (hexahydro-6-methyl-2-oxopyrimidinyl...Specific Chemical Substances § 721.9920 Urea, (hexahydro-6-methyl-2-oxopyrimidinyl...reporting. (1) The chemical substance urea,...

2010-07-01

279

40 CFR 721.9920 - Urea, (hexahydro-6-methyl-2-oxopyrimidinyl)-.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 2011-07-01 false Urea, (hexahydro-6-methyl-2-oxopyrimidinyl...Specific Chemical Substances § 721.9920 Urea, (hexahydro-6-methyl-2-oxopyrimidinyl...reporting. (1) The chemical substance urea,...

2011-07-01

280

40 CFR 418.30 - Applicability; description of the urea subcategory.  

Code of Federal Regulations, 2011 CFR

...true Applicability; description of the urea subcategory. 418.30 Section 418...FERTILIZER MANUFACTURING POINT SOURCE CATEGORY Urea Subcategory § 418.30 Applicability; description of the urea subcategory. The provisions of...

2011-07-01

281

Urinary BDNF-to-creatinine ratio is associated with aerobic fitness.  

PubMed

Circulating levels of brain-derived neurotrophic factor (BDNF) are known to be affected by aerobic exercise. As the previous research focus in humans has been to examine peripheral BDNF levels through blood, serum, and platelet assay, the present study investigated the association between basal urinary BDNF concentration and indices of aerobic fitness in a sample of young adults (n=52). Aerobic fitness was evaluated with self-report of exercise habits and heart rate (HR) assessment during a sub-maximal Step Test. BDNF concentration was determined by enzyme-linked immunosorbent assay and adjusted for creatinine. Results indicated that the basal BDNFlog/creatinine ratio was positively associated with greater frequency of exercise and, during aerobic challenge, a quicker rise in HR upon exercise, lower peak HR during exercise, and lower HR during the recovery period, each indicative of enhanced fitness. These results highlight the utility of urine capture as a non-invasive technique to assess for exercise-mediated changes in peripheral BDNF. PMID:24334166

Collins, Larisa R; Koven, Nancy S

2014-01-24

282

Ocean urea fertilization for carbon credits poses high ecological risks  

Microsoft Academic Search

The proposed plan for enrichment of the Sulu Sea, Philippines, a region of rich marine biodiversity, with thousands of tonnes of urea in order to stimulate algal blooms and sequester carbon is flawed for multiple reasons. Urea is preferentially used as a nitrogen source by some cyanobacteria and dinoflagellates, many of which are neutrally or positively buoyant. Biological pumps to

Patricia M. Glibert; Rhodora Azanza; Michele Burford; Ken Furuya; Eva Abal; Adnan Al-Azri; Faiza Al-Yamani; Per Andersen; Donald M. Anderson; John Beardall; G. Mine Berg; Larry Brand; Deborah Bronk; Justin Brookes; JoAnn M. Burkholder; Allan Cembella; William P. Cochlan; Jackie L. Collier; Yves Collos; Robert Diaz; Martina Doblin; Thomas Drennen; Sonya Dyhrman; Yasuwo Fukuyo; Miles Furnas; James Galloway; Edna Granéli; Dao Viet Ha; Gustaaf Hallegraeff; John Harrison; Paul J. Harrison; Cynthia A. Heil; Kirsten Heimann; Robert Howarth; Cécile Jauzein; Austin A. Kana; Todd M. Kana; Hakgyoon Kim; Raphael Kudela; Catherine Legrand; Michael Mallin; Margaret Mulholland; Shauna Murray; Judith O’Neil; Grant Pitcher; Yuzao Qi; Nancy Rabalais; Robin Raine; Sybil Seitzinger; Paulo S. Salomon; Caroline Solomon; Diane K. Stoecker; Gires Usup; Joanne Wilson; Kedong Yin; Mingjiang Zhou; Mingyuan Zhu

2008-01-01

283

Measuring urea persistence, distribution and transport on coastal plain soils  

Technology Transfer Automated Retrieval System (TEKTRAN)

The persistence and mobility of urea, an organic form of nitrogen present in animal manures and commercial fertilizers, has rarely been studied and measured, because it is assumed to undergo rapid hydrolysis to ammonia. However, preliminary studies have shown urea to exist in leachate and runoff sev...

284

Variability of urea concentration in camel milk in Kazakhstan  

E-print Network

Note Variability of urea concentration in camel milk in Kazakhstan Bernard FAYE 1*, Gaukhar-protein nitrogen in milk. The variability of its concentration was never reported in camel milk. The present communication aimed to give some reference values on urea content in camel milk and to explore some

Paris-Sud XI, Université de

285

Branchial and renal urea transport mechanisms in three teleost fish  

Microsoft Academic Search

Physiological and pharmacological approaches were used to characterize the pulsatile, facilitated diffusion urea transport mechanism (tUT) known from molecular evidence to be present in the gills of the facultatively ureotelic gulf toadfish (Opsanus beta). Using those findings, potential urea transport mechanisms in the kidney of the toadfish and in both excretory organs of the ammoniotelic plainfin midshipman (Porichthys notatus), closely

M. Danielle McDonald

2002-01-01

286

Molecular Basis of the Apparent Near Ideality of Urea Solutions.  

SciTech Connect

The research described in this product was performed in part in the Environmental Molecular Sciences Laboratory, a national scientific user facility sponsored by the Department of Energy's Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory. Activity coefficients of urea solutions are calculated to explore the mechanism of its solution properties, which form the basis for its well-known use as a strong protein denaturant. We perform free energy simulations of urea solutions in different urea concentrations using two urea models (OPLS and KBFF models) to calculate and decompose the activity coefficients. For the case of urea, we clarify the concept of the ideal solution in different concentration scales and standard states and its effect on our subsequent analysis. The analytical form of activity coefficients depends on the concentration units and standard states. For both models studied, urea displays a weak concentration dependence for excess chemical potential. However, for the OPLS force-field model, this results from contributions that are independent of concentration to the van der Waals and electrostatic components whereas for the KBFF model those components are nontrivial but oppose each other. The strong ideality of urea solutions in some concentration scales (incidentally implying a lack of water perturbation) is discussed in terms of recent data and ideas on the mechanism of urea denaturation of proteins.

Kokubo, Hironori; Rosgen, Jorg; Bolen, D Wayne; Pettitt, Bernard M.

2007-11-01

287

Managing Urea-Containing Fertilizers1 Larry G. Bundy2  

E-print Network

Nitrogen fertilizer use in Wisconsin as anhydrous ammonia, urea-ammonium nitrate solutions, and urea ranged such as ammonium nitrate, ammonium sulfate, ammonium thiosulfate, aqua ammonia, calcium nitrate and others. Utilization as ammonium nitrate plus ammonium sulfate ranged from about 24,000 tons of N in 1999 to 13

Balser, Teri C.

288

Ammonium assimilation in Proteus vulgaris, Bacillus pasteurii , and Sporosarcina ureae  

Microsoft Academic Search

No active uptake of ammonium was detected in Proteus vulgaris, Bacillus pasteurii, and Sporosarcina ureae, which indicates that these bacteria depend on the passive diffusion of ammonia across the cell membrane. In P. vulgaris the glutamine synthetase-glutamate synthase (GS-GOGAT) pathway and glutamate dehydrogenase (GDH) were present, and these enzymes exhibited high affinities for ammonium. In B. pasteurii and S. ureae,

Gerhard Miirsdorf; Heinrich Kaltwasser

1989-01-01

289

Rapid method for detection of urea hydrolysis by yeasts.  

PubMed Central

A method is described for the rapid detection of urea hydrolysis by yeasts, using the Berthelot color reaction. The results could be determined within 30 to 50 min with this method, compared with 8 to 72 h usually required with Christensen urea agar. PMID:322609

Paliwal, D K; Randhawa, H S

1977-01-01

290

Structure and permeation mechanism of a mammalian urea transporter  

SciTech Connect

As an adaptation to infrequent access to water, terrestrial mammals produce urine that is hyperosmotic to plasma. To prevent osmotic diuresis by the large quantity of urea generated by protein catabolism, the kidney epithelia contain facilitative urea transporters (UTs) that allow rapid equilibration between the urinary space and the hyperosmotic interstitium. Here we report the first X-ray crystal structure of a mammalian UT, UT-B, at a resolution of 2.36 {angstrom}. UT-B is a homotrimer and each protomer contains a urea conduction pore with a narrow selectivity filter. Structural analyses and molecular dynamics simulations showed that the selectivity filter has two urea binding sites separated by an approximately 5.0 kcal/mol energy barrier. Functional studies showed that the rate of urea conduction in UT-B is increased by hypoosmotic stress, and that the site of osmoregulation coincides with the location of the energy barrier.

Levin, Elena J.; Cao, Yu; Enkavi, Giray; Quick, Matthias; Pan, Yaping; Tajkhorshid, Emad; Zhou, Ming (UIUC); (Columbia)

2012-09-17

291

The Association between Serum Uric Acid Level and Incidence of Metabolic Syndrome according to Menopausal Status in Korean Women  

PubMed Central

Objectives The aim of this study is to investigate the association between serum uric acid level and metabolic syndrome according to menopausal status in Korean women. Methods A total of 2,241 women who visited to the health promotion center at Pusan National University Hospital from 2010 to 2014 were included in this cross-sectional study. Self-report questionnaires and interviews with healthcare providers were used to assess disease history, medication history, menstrual history and body size measuring. Anthropometric measurements and laboratory results were compared as presence of metabolic syndrome and menopausal status by student-t test. Logistic regression analysis was performed between presence of metabolic syndrome and presumable predictive factors, such as age, menopause and serum uric acid. Results The prevalence rate of metabolic syndrome were 7.45% (63/846) in pre-menopausal group and 23.87% (333/1395) in menopausal group. Serum uric acid level was higher in menopausal women than premenopausal women (4.6 ± 1.1 vs. 4.3 ± 0.9. P = 0.000). And, its concentration was also higher in metabolic syndrome than normal women regarding of menopausal statue (premenopause 4.7 ± 1.1 vs. 4.2 ± 0.8, P = 0.001, menopause 4.9 ± 1.3 vs. 4.5 ± 1.0, P = 0.000). Multiple logistic regression analysis showed serum uric acid and age have relationship with metabolic syndrome (OR: 1.453, 95% confidence interval [CI]: 1.074-1.111, P = 0.000; OR: 1.092, 95% CI: 1.305-1.619, P = 0.000). Conclusion We could find out some potential of uric acid as predictive factor for metabolic syndrome in premenopausal and menopausal group. Further investigation is required to clarify the relationship between serum uric acid, menopause and metabolic syndrome. PMID:25580424

Joo, Jong Kil; Hong, Gil Pyo; Han, Si Eun; Lee, Young Ju; Kim, Seung Chul; Kim, Chang Woon

2014-01-01

292

Renal ammonium excretion after an acute acid load: blunted response in uric acid stone formers but not in patients with type 2 diabetes  

PubMed Central

Idiopathic uric acid nephrolithiasis is characterized by elevated urinary net acid excretion and insufficient buffering by ammonium, resulting in excessively acidic urine and titration of the relatively soluble urate anion to insoluble uric acid. Patients with type 2 diabetes have similar changes in urinary pH, net acid excretion, and ammonium in 24-h urine collections at baseline, even after controlling for dietary factors, and are at increased risk for uric acid nephrolithiasis. However, not all patients with type 2 diabetes develop kidney stones, suggesting that uric acid stone formers may have additional urinary defects, perhaps not apparent at baseline. We performed a metabolic study of 14 patients with idiopathic uric acid nephrolithiasis, 13 patients with type 2 diabetes, and 8 healthy control subjects of similar body mass index. After equilibration on a fixed diet for 5 days, subjects were given a single oral acid load (50 meq ammonium chloride), and urine was collected hourly for 4 h. Uric acid stone formers had a lower ammonium excretory response to acute acid loading compared with diabetic and nondiabetic nonstone formers, suggesting that an ammonium excretory defect unique to uric acid stone formers was unmasked by the acid challenge. The Zucker diabetic fatty rat also did not show impaired urinary ammonium excretion in response to acute acid challenge. A blunted renal ammonium excretory response to dietary acid loads may contribute to the pathogenesis of idiopathic uric acid nephrolithiasis. PMID:24026180

Bobulescu, I. Alexandru; Maalouf, Naim M.; Capolongo, Giovanna; Adams-Huet, Beverley; Rosenthal, Tara R.; Moe, Orson W.

2013-01-01

293

Monitoring of antioxidant properties of uric acid in humans for a consideration measuring of levels of allantoin in plasma by liquid chromatography  

Microsoft Academic Search

Uric acid is the end product of purine metabolism in humans. It has been pointed out that uric acid acts as an antioxidant and is capable to react with biologically relevant oxidants to form allantoin. Therefore, measurement of allantoin in humans was proposed as a marker of oxidative stress. We estimated allantoin in human plasma obtained from the patients with

Roman Kand'ár; Pavla Žáková; Vladimíra Mužáková

2006-01-01

294

Functionalized multilayered graphene platform for urea sensor.  

PubMed

Multilayered graphene (MLG) is an interesting material for electrochemical sensing and biosensing because of its very large 2D electrical conductivity and large surface area. We propose a less toxic, reproducible, and easy method for producing functionalized multilayer graphene from multiwalled carbon nanotubes (MWCNTs) in mass scale using only concentrated H(2)SO(4)/HNO(3). Electron microscopy results show the MLG formation, whereas FTIR and XPS data suggest its carboxylic and hydroxyl-functionalized nature. We utilize this functionalized MLG for the fabrication of a novel amperometric urea biosensor. This biosensor shows linearity of 10-100 mg dL(-1), sensitivity of 5.43 ?A mg(-1) dL cm(-2), lower detection limit of 3.9 mg dL(-1), and response time of 10 s. Our results suggest that MLG is a promising material for electrochemical biosensing applications. PMID:22117758

Srivastava, Rajesh K; Srivastava, Saurabh; Narayanan, Tharangattu N; Mahlotra, Bansi D; Vajtai, Robert; Ajayan, Pulickel M; Srivastava, Anchal

2012-01-24

295

Nanoparticulate silver increases uric acid and allantoin excretion in rats, as identified by metabolomics.  

PubMed

Metabolomic investigation of rat urine was employed to identify mammalian metabolites affected by ionic or nanoparticulate silver. Female and male Wistar rats were administered silver nanoparticles (2.25, 4.5 or 9.0 mg kg(-1) body weight per day) or ionic silver (silver acetate, 9.0 mg silver kg(-1) bw per day) by oral gavage for 28 days. On day 18, urine was collected for 24 h and subjected to metabolomics with high performance liquid chromatography-quadropole time-of-flight mass spectrometry (HPLC-QTOF-MS)-based separation and detection. Principal component analysis was subsequently applied to the data. Metabolomic differences in urine composition were found in female rats but not in male rats. Several metabolites were identified by the use of elemental composition calculated from the exact mass combined with searches in the Human Metabolome Database.The metabolite identities were eventually verified by co-chromatography with authentic standards. Differences were found in uric acid and its degradation product, allantoin. Administration of nanoparticulate silver increased both metabolites, whereas ionic silver only increased allantoin. In conclusion, metabolomic investigation of rat urine showed that increased levels of uric acid and allantoin were associated with exposure to nanoparticulate silver. PMID:22610381

Hadrup, Niels; Lam, Henrik R; Loeschner, Katrin; Mortensen, Alicja; Larsen, Erik H; Frandsen, Henrik

2012-11-01

296

Enzyme-entrapped mesoporous silica for treatment of uric acid disorders.  

PubMed

Gout is an abnormality in the body resulting in the accumulation of uric acid mainly in joints. Dissolution of uric acid crystals into soluble allantoin by the enzyme uricase might provide a better alternative for the treatment of gout. This work aims to investigate the feasibility of a transdermal patch loaded with uricase for better patient compliance. Mesoporous silica (SBA-15) was chosen as the matrix for immobilisation of uricase. Highly oriented mesoporous SBA-15 was synthesized, characterized and uricase was physisorbed in the mesoporous material. The percentage adsorption and release of enzyme in borate buffer was monitored. The release followed linear kinetics and greater than 80% enzyme activity was retained indicating the potential of this system as an effective enzyme immobilization matrix. The enzyme permeability was studied with Wistar rat skin and human cadaver skin. It was found that in case of untreated rat skin 10% of enzyme permeated through skin in 100 h. The permeation increased by adding permeation enhancer (combination of oleic acid in propylene glycol (OA in PG)). The permeation enhancement was studied under two concentrations of OA in PG (1%, 5%) in both rat and human cadaver skin and it was found that 1% OA in PG showed better result in rat skin and 5% OA in PG showed good results in human cadaver skin. PMID:23802423

Muthukoori, Shanthini; Narayanan, Naagarajan; Chandra, Manuguri Sesha Sarath; Sethuraman, Swaminathan; Krishnan, Uma Maheswari

2013-05-01

297

Comparison of plasma uric acid levels in five varieties of the domestic turkey, Meleagris gallopavo.  

PubMed

Plasma uric acid (PUA) is a consensus physiological biomarker for many phenotypes in vertebrates because it is a reliable indicator for processes such as oxidative stress and tubular function. In birds, it is considered a major antioxidant and is also the primary endproduct of nitrogen metabolism. Despite this importance, knowledge of baseline levels of PUA in physiologically normal birds, including the turkey, Meleagris gallopavo, is limited. Here, we compared PUA levels in a total of 106 apparently normal male and female birds at 8 and 32 wk of age from 5 strains of the domestic turkey, including Bourbon Red, Narragansett, Blue Slate, Royal Palm, and Spanish Black. Though differences in PUA were not significant at 8 and 32 wk of age, BW, variety, and sex effects were highly significant. When adjusted for BW, female birds had, on average, a higher PUA per kilogram of BW than male birds. When adjusted for both sex and BW, Royal Palm birds had the lowest average PUA, and Blue Slate had the highest PUA. Results of these investigations represent the first comparative analysis of PUA in physiologically normal turkey varieties. They suggest that differences in basal plasma levels of uric acid in physiologically normal turkeys are influenced by sex, weight, and genetic background but may be independent of age. PMID:17012170

Hartman, S; Taleb, S A; Geng, T; Gyenai, K; Guan, X; Smith, E

2006-10-01

298

Bilateral uric acid nephrolithiasis and ureteral hypertrophy in a free-ranging river otter (Lontra canadensis)  

USGS Publications Warehouse

We report the first case of uric acid nephrolithiasis in a free-ranging river otter (Lontra canadensis). A 7 yr old male river otter collected from the Skagit River of western Washington (USA) had bilateral nephrolithiasis and severely enlarged ureters (one of 305 examined [0.33%]). The uroliths were 97% uric acid and 3% protein. Microscopic changes in the kidney were confined to expansion of renal calyces, minor loss of medullary tissue, and multifocal atrophy of the cortical tubules. No inflammation was observed in either kidney or the ureters. The ureters were enlarged due to marked hypertrophy of smooth muscle plus dilation of the lumen. Fusion of the major calyces into a single ureteral lumen was several cm distal to that of two adult male otters used as histopathologic control specimens. This case report is part of a large contaminant study of river otters collected from Oregon and Washington. It is important to understand diseases and lesions of the otter as part of our overall evaluation of this population.

Grove, Robert A.; Bildfell, Rob; Henny, Charles J.; Buhler, D.R.

2003-01-01

299

Association of rheumatoid factor and uric acid with psoriatic arthritis: a review.  

PubMed

Psoriatic arthritis is a condition that causes inflammation of the joints of psoriatic patients. Psoriatic arthritis also affects tissues surrounding the joints including tendon and ligaments. Psoriatic arthritis (PsA), recognized for over 100 years, is the second most frequent diagnostic category after Rhematoid Arthritis (RA) and occurring up to 10% of patients with skin psoriasis. Although PsA is a sero-negative arthritis and the absence of rheumatoid factor is a characteristic laboratory finding, it may be present in 3% of psoriatic arthritis (PsA) patients. Hyperuricaemia has been generally accepted as a frequent accompaniment of psoriasis and psoriatic arthritis. It has been postulated that the hyperuricaemia results from increased purine synthesis from the rapid epidermal cell turnover. With its uniquely diverse pathophysiologic and clinical features and the ability to progress into one of the most destructive arthritis known as, psoriatic arthritis (PsA), remains a challenging disease deserving of the attention in recent years. High level of serum uric acid is a risk factor for many diseases like gout, hypertension, coronary heart diseases etc. Patients with PsA remain vulnerable for many diseases like above mentioned one. So, hyperurecemia may play a vicious link with PsA and gout, hypertension and so many diseases. This article may help all dermatologists and researchers for further evaluation of serum uric acid and RA factor in psoriatic arthritis (PsA) patients. PMID:25178623

Khondker, L; Khan, S I

2014-07-01

300

Comparatve uric acid lowering studies of allopurinol with an indigenous medicinal plant in rabbits.  

PubMed

The aim of this research was to carry out a comparative study of lowering of uric acid by the use of dried powder of Colchicum luteum and allopathic drug (allopurinol) in rabbits, to determine whether herbal drugs can be used by patients instead of allopathic drugs. The herbal medicine, dried corm powder of Colchicum luteum 2.5 mg/kg/day and dried powder of allopurinol 2 mg/kg/day an allopathic medicine, was used in the study. The results of these medicines were observed in animal model, using 12 adult rabbits, which were divided into three groups A, B and C, respectively, where group C was taken as control. The SPSS version 17 was used for statistical analysis and analysis of variance (ANOVA) was used for comparing the data in different groups and the level of significance was 5%. It was resulted that dried corm of Colchicum luteum significantly reduced the uric acid in adult rabbits as reduced by allopathic medicine--allopurinol. In the light of present research we concluded that the herbal medicines can be used in lieu of allopathic drugs. Thus, the risk of side effects that are associated with the prolonged use of allopathic drugs can be minimized. PMID:25362814

Mohammad, Imran Shair; Latif, Sana; Yar, Muhammad; Nasar, Faiza; Ahmad, Irshad; Naeem, Muhammad

2014-01-01

301

Association of Serum Uric Acid and Coronary Artery Disease in Premenopausal Women  

PubMed Central

Objective To date, no study in the published literature has investigated the role of various serum uric acid (SUA) concentrations in the development of angiographically-proven coronary artery disease (CAD) in premenopausal women. Therefore, the aim of this study was to investigate the role SUA levels may play in the prevalence, severity, and prognosis of CAD in premenopausal women. Methods This cross-sectional retrospective study included 607 premenopausal women who had undergone coronary angiography. The CAD diagnosis was based upon stenosis affecting ?50% of the luminal diameter. Association of the SUA levels with CAD prevalence, severity, and clinical outcomes were assessed by statistical analysis. Results In total, 369 (60.8%) of the patients were diagnosed with CAD. The CAD patients had significantly higher SUA levels than those without CAD (5.3±1.9 vs. 4.8±1.7 mg/dL, P?=?0.001). The SUA levels were found to be significantly associated with CAD prevalence (P?=?0.013). Patients with higher levels of SUA also showed increased rates of multivessel disease and composite end-points, such as major adverse cardiac events. Furthermore, multivariate analysis identified abnormally high levels of uric acid (hyperuricemia) as an independent risk factor for CAD (OR 1.51 (1.11–2.53), P<0.05). Conclusions The SUA levels are significantly associated with the prevalence of CAD. The SUA levels may be a predictor for incidence of major cardiovascular events in premenopausal women. PMID:25184207

Zhang, Jian-wei; He, Ling-jie; Cao, Shu-jun; Yang, Qing; Yang, Shi-wei; Zhou, Yu-jie

2014-01-01

302

Carbon nanoparticles with tosyl functional group for distinguishing voltammetric peaks of ascorbic acid and uric acid.  

PubMed

In this approach, electro-oxidation of a mixture of uric acid and ascorbic acid at the surface of tosyl surface carbon nanoparticles/glassy carbon electrode has been performed. The electro-oxidation of these compounds at bare electrode is sluggish and there is no suitable peak separation between them. However, using functionalized carbon nanoparticles, two well-defined anodic peaks with a considerable enhancement in the peak current and a remarkable peak potential separation near 452 mV is obtained. The porous interfacial layer of the carbon nanoparticles modified electrode with a high specific surface area increases the conductive area; molecules can penetrate through the conductive porous channels onto the electrode more easily so leading to higher sensitivity and selectivity. The dynamic linear ranges of 1.0 × 10(-5) to 3.0 × 10(-3)M and 1.0 × 10(-7) to 1.0 × 10(-4)M with detection limits 1.0 × 10(-5)M and 2.0 × 10(-8)M (for S/N=3) were obtained for ascorbic acid and uric acid, respectively. Analytical utility of the modified electrode has been examined successfully using human urine samples and vitamin C commercial tablets. PMID:25492188

Amiri, Mandana; Imanzadeh, Hamideh; Banaei, Alireza

2015-02-01

303

FRET-Aptamer Assays for Bone Marker Assessment, C-Telopeptide, Creatinine, and Vitamin D  

NASA Technical Reports Server (NTRS)

Astronauts lose 1.0 to 1.5% of their bone mass per month on long-duration spaceflights. NASA wishes to monitor the bone loss onboard spacecraft to develop nutritional and exercise countermeasures, and make adjustments during long space missions. On Earth, the same technology could be used to monitor osteoporosis and its therapy. Aptamers bind to targets against which they are developed, much like antibodies. However, aptamers do not require animal hosts or cell culture and are therefore easier, faster, and less expensive to produce. In addition, aptamers sometimes exhibit greater affinity and specificity vs. comparable antibodies. In this work, fluorescent dyes and quenchers were added to the aptamers to enable pushbutton, one-step, bind-and-detect fluorescence resonance energy transfer (FRET) assays or tests that can be freeze-dried, rehydrated with body fluids, and used to quantitate bone loss of vitamin D levels with a handheld fluorometer in the spacecraft environment. This work generated specific, rapid, one-step FRET assays for the bone loss marker C-telopeptide (CTx) when extracted from urine, creatinine from urine, and vitamin D congeners in diluted serum. The assays were quantified in nanograms/mL using a handheld fluorometer connected to a laptop computer to convert the raw fluorescence values into concentrations of each analyte according to linear standard curves. DNA aptamers were selected and amplified for several rounds against a 26- amino acid form of CTx, creatinine, and vitamin D. The commonalities between loop structures were studied, and several common loop structures were converted into aptamer beacons with a fluorophore and quencher on each end. In theory, when the aptamer beacon binds its cognate target (CTx bone peptide, creatinine, or vitamin D), it is forced open and no longer quenched, so it gives off fluorescent light (when excited) in proportion to the amount of target present in a sample. This proportional increase in fluorescence is called a "lights on" FRET response. The vitamin D aptamer beacon gives a "lights off" or inversely proportional fluorescence response to the amount of vitamin D present in diluted serum. These FRET-aptamer assays are rapid (<30 minutes), sensitive (low ng/mL detection limits), and quite easy to carry out (add sample, mix, and detect in the handheld reader). Benefits include the speed of the assays as well as the small amount of space taken up by the handheld reader and cuvette assays. The aptamer DNA sequences represent novel additional features of the existing (patent-pending) FRET-aptamer assay platform.

Bruno, John G.

2013-01-01

304

Trehalose protects urea-induced unfolding of ?-chymotrypsin.  

PubMed

Trehalose, a naturally occurring osmolyte, appears to be one of the most effective protectants for enzymes under various stress conditions while urea, a classical denaturant, destabilizes the activity, function, and alters the native structure of proteins. Herein, we have characterized the counteracting effects of trehalose on the deleterious effect of urea on ?-chymotrypsin (CT) through the calorimetric data (transition temperature (T(m)), enthalpy change (?H), heat capacity change (?C(p)) and Gibbs free energy of unfolding (?G(u)) by using differential scanning calorimeter (DSC) and circular dichroism (CD) techniques, respectively, at a 1:2 ratio of trehalose and urea, as well as various urea concentration (up to 6 M) in the presence of 1 M trehalose. Our parallel experimental results explicitly elucidate that trehalose strongly offset the deleterious actions of urea on CT at 1:2 molar ratio of trehalose and urea, however, trehalose (1 M) some how failed to counteract the perturbation effects of urea (3-6 M) on CT. PMID:20691724

Kumar, Awanish; Attri, Pankaj; Venkatesu, Pannuru

2010-11-01

305

Administration of tomato juice ameliorates lactate dehydrogenase and creatinine kinase responses to anaerobic training.  

PubMed

Creatinine phosphokinase (CPK) and lactate dehydrogenase (LDH) are important biological markers of various myocardial disorders and exercise-induced muscle damage. Lycopene, on the other side, is a natural anti-oxidant with protective action against cardiovascular risk. Fifteen anaerobically trained athletes with elevated LDH and CPK baseline levels were enrolled in this study after undergoing thorough biochemical and cardiovascular evaluation with echocardiocraphy. In nine athletes tomato juice, a lycopene plain juice, was administered during and after exercise, replacing the carbohydrate supplementation beverages commonly used during training for over a 2-month period. Tomato juice administration significantly reduced LDH and CPK levels, which returned back to almost normal levels. At the same time homocysteine and C-reactive protein were also attenuated. No changes were observed in the control group, where the usual carbohydrate supplementation had been followed. PMID:23291317

Tsitsimpikou, Christina; Kioukia-Fougia, Nassia; Tsarouhas, Konstantinos; Stamatopoulos, Panagiotis; Rentoukas, Elias; Koudounakos, Aris; Papalexis, Peter; Liesivuori, Jyrki; Jamurtas, Athanasios

2013-11-01

306

Effect of visceral fat accumulation on uric acid metabolism in male obese subjects: Visceral fat obesity is linked more closely to overproduction of uric acid than subcutaneous fat obesity  

Microsoft Academic Search

We investigated the relationship between uric acid (UA) metabolism and fat distribution in 36 obese men with a mean ± SD age of 38 ± 16 years and mean body-mass index (BMI) of 34 ± 4 kg\\/m2. Subjects were divided into two groups: subcutaneous fat obesity (SFO) and visceral fat obesity (VFO), according to their abdominal fat distribtion based on

Fumihiko Matsuura; Shizuya Yamashita; Tadashi Nakamura; Makoto Nishida; Shuichi Nozaki; Tohru Funahashi; Yuji Matsuzawa

1998-01-01

307

Early and small changes in serum creatinine concentrations are associated with mortality in mechanically ventilated patients.  

PubMed

Emerging evidence suggests that minor changes in serum creatinine concentrations are associated with increased hospital mortality rates. However, whether serum creatinine concentration (SCr) on admission and its change are associated with an increased mortality rate in mechanically ventilated patients is not known. We have conducted an international, prospective, observational cohort study enrolling adult intensive care unit patients under mechanical ventilation (MV). Recursive partitioning was used to determine the values of SCr at the start of MV (SCr0) and the change in SCr ([DeltaSCr] defined as the maximal difference between the value at start of MV [day 0] and the value on MV day 2 at 8:00 am) that best discriminate mortality. In-hospital mortality, adjusted by a proportional hazards model, was the primary outcome variable. A total of 2,807 patients were included; median age was 59 years and median Simplified Acute Physiology Score II was 44. All-cause in-hospital mortality was 44%. The variable that best discriminated outcome was a SCr0 greater than 1.40 mg/dL (mortality, 57% vs. 36% for patients with SCr0

Nin, Nicolás; Lombardi, Raúl; Frutos-Vivar, Fernando; Esteban, Andrés; Lorente, José A; Ferguson, Niall D; Hurtado, Javier; Apezteguia, Carlos; Brochard, Laurent; Schortgen, Fréderique; Raymondos, Konstantinos; Tomicic, Vinko; Soto, Luis; González, Marco; Nightingale, Peter; Abroug, Fekri; Pelosi, Paolo; Arabi, Yaseen; Moreno, Rui; Anzueto, Antonio

2010-08-01

308

Validation of creatinine assays utilizing HPLC and IDMS traceable standards in sera of children  

PubMed Central

The purpose of this study was to validate serum creatinine (SCr) concentrations assayed in the Central Biochemistry Laboratory of the National Institutes of Health (NIH)-funded Chronic Kidney Disease in Children (CKiD) study utilizing an enzymatic assay (Siemens Advia 2400) against a method traceable to reference isotope dilution mass spectroscopy (IDMS) developed by the National Institute of Standards and Technology (NIST). High-performance liquid chromatography (HPLC) measured SCr after external validation utilizing IDMS-based standard reference materials. Sera from the first 201 subjects enrolled in CKiD were analyzed and compared for creatinine concentration by enzymatic and HPLC methods. Fifty “normal” pediatric sera were subsequently analyzed. Finally, a “pediatric” reference standard was prepared and examined for accuracy and precision. Enzymatic SCr concentrations (median 1.4 mg/dl) of CKiD subjects were well correlated with HPLC (r=0.984) but were slightly higher (+7%; p<0.001). Agreement was poorer at lower SCr (median 0.4 mg/dl) when using samples from normal children and the “pediatric” reference standard. However, the Roche enzymatic assay was comparable with HPLC in accuracy and precision. Referring physicians should be aware of the accuracy and reproducibility of their laboratory's SCr assay. Our enzymatic assay agreed well with HPLC in CKiD subjects with elevated SCr. We suggest that NIST develop a pediatric SCr standard reference material for use by assay manufacturers to improve accuracy and precision of assays at the low SCr levels observed in most pediatric patients. PMID:18769945

Kwong, Tai; Erway, Brian; Warady, Bradley; Sokoll, Lori; Hellerstein, Stanley; Dharnidharka, Vikas; Furth, Susan; Muñoz, Alvaro

2009-01-01

309

Urea encapsulation in modified starch matrix for nutrients retention  

NASA Astrophysics Data System (ADS)

It has been estimated that 20-70% of the used urea goes to the environment via leaching, nitrification and volatilization which not only harms the environment but also reduces the urea efficiency. By coating the urea granules, the farmers can achieve high urea performance through controlling the excess release of nitrogen. Up until now, different materials have been tested for nutrients retention. However, most of them are either expensive or unfriendly to the environment. Being cheap and biodegradable materials, the starches may also be used to coat the urea fertilizer for controlling the nutrients release. However, the pure starches do not meet the standards set by many industrial processes due to their slow tacking and too low viscosities and should be modified for getting smooth, compact and mechanically stronger coatings. In these studies, the tapioca starch was modified by reacting it with urea and different masses of borax. The prepared solutions were used to coat the urea granules of 3.45 mm average diameter. Different volumes (1, 1.5 and 2 mL) of each solution were used to coat 30 g of urea fluidized above the minimum level of fluidization. It was noticed that the coating thickness, percent coating, dissolution rate and percent release follow an increasing trend with an increase of solution volume; however, some random results were obtained while investigating the solution volume effects on the percent release. It was seen that the nutrients percent release over time increases with an increase in solution volume from 1 to 1.5 mL and thereafter reaches to a steady state. It confirms that the 1.5 mL of solution for 30 g urea samples will give the optimized coating results.

Naz, Muhammad Yasin; Sulaiman, Shaharin Anwar; Ariff, Mohd. Hazwan Bin Mohd.; Ariwahjoedi, Bambang

2014-10-01

310

Comparison of Serum Concentrations of ?-Trace Protein, ?2-Microglobulin, Cystatin C, and Creatinine in the US Population  

PubMed Central

Summary Background and objectives ?-trace protein (?TP), ?2-microglobulin (?2M), and cystatin C (CysC) have advantages over creatinine for estimating GFR and prognosis. This study compares the distribution of all four markers in the general population and their associations with possible determinants of GFR. Design, setting, participants, & measurements ?TP and ?2M were measured in 7596 participants (aged ?12 years) of the Third National Health and Nutrition Examination Survey (1988–1994). ?TP and ?2M concentrations and the proportion of persons with elevated (?99th percentile for young healthy participants) ?TP (?0.81 mg/L), ?2M (?2.80 mg/L), standardized CysC (?1.03 mg/L), and creatinine (?1.2 mg/dl for men and ?1.0 mg/dl for women) were compared across demographic and clinical factors. Results Elevated ?TP, ?2M, and CysC showed stronger associations with age than elevated serum creatinine, the prevalence of elevated levels reaching 47%, 44%, 58%, and 26%, respectively, by age 80 years. ?TP, CysC, and creatinine were higher in men but ?2M was not associated with sex. Mexican Americans had lower ?TP, ?2M, CysC, and creatinine compared with non-Hispanic whites. Hypertension and higher C-reactive protein were associated with elevations in all markers, whereas non-Hispanic black race, body mass index, diabetes, smoking status, triglycerides, HDL cholesterol, and education were not associated in a consistent manner across the different markers. Conclusions ?TP, ?2M, CysC, and creatinine differ in their associations with demographic and clinical factors, suggesting variation in their non-GFR determinants. Future studies should examine these markers with measured GFR to determine their diagnostic and prognostic utility. PMID:23335043

Juraschek, Stephen P.; Coresh, Josef; Inker, Lesley A.; Levey, Andrew S.; Köttgen, Anna; Foster, Meredith C.; Astor, Brad C.; Eckfeldt, John H.

2013-01-01

311

Effect of processing parameters for electrocatalytic properties of SnO(2) thin film matrix for uric acid biosensor.  

PubMed

RF sputtered tin oxide (SnO2) thin film matrix has been efficiently exploited for the detection of uric acid. The deposition parameters for SnO2 thin film have been optimized to yield better electrocatalytic properties. A correlation between its electrocatalytic properties with the structural and electrical properties has been made. SnO2 thin film prepared under optimized growth parameter (70% argon in reactive gas ambient of Ar and O2) exhibits higher mobility of charge carrier and high carrier concentration thereby resulting in enhanced charge transfer characteristics. High surface coverage of uricase onto SnO2 thin films (4.28 × 10(-4) mole cm(-2)), low value of Michaelis-Menten constant (km) 0.18 mM, good linearity in detection of uric acid in the range 0.05-1.00 mM and a fast response of 5 s are attractive features of prepared SnO2 thin film based bioelectrodes for efficient detection of uric acid. The nanoporous and rough surface morphology of SnO2 thin film besides its high carrier mobility in comparison to that of ITO is responsible for the obtained enhanced sensitivity (?700 ?A mM(-1)) and improved sensing response characteristics towards uric acid. PMID:24396852

Arora, Kashima; Tomar, Monika; Gupta, Vinay

2014-02-21

312

Disposable biosensor based on cathodic electrochemiluminescence of tris(2,2-bipyridine)ruthenium(II) for uric acid determination.  

PubMed

A new method for uric acid (UA) determination based on the quenching of the cathodic ECL of the tris(2,2-bipyridine)ruthenium(II)-uricase system is described. The biosensor is based on a double-layer design containing first tris(2,2-bipyridine)ruthenium(II) (Ru(bpy)3(2+)) electrochemically immobilized on graphite screen-printed cells and uricase in chitosan as a second layer. The uric acid biosensing is based on the ECL quenching produced by uric acid over the cathodic ECL caused by immobilized Ru(bpy)3(2+) in the presence of uricase. The use of a -1.1 V pulse for 1s with a dwelling time of 10s makes it possible to estimate the initial enzymatic rate, which is used as the analytical signal. The Stern-Volmer type calibration function shows a dynamic range from 1.0×10(-5) to 1.0×10(-3)M with a limit of detection of 3.1×10(-6)M and an accuracy of 13.6% (1.0×10(-4)M, n=5) as relative standard deviation. Satisfactory results were obtained for urine samples, creating an affordable alternative for uric acid determination. PMID:23498698

Ballesta-Claver, J; Rodríguez-Gómez, R; Capitán-Vallvey, L F

2013-04-01

313

Uric acid concentration in subjects at risk of type 2 diabetes mellitus: Relationship to components of the metabolic syndrome  

Microsoft Academic Search

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

A. Costa; J. Bedini; I. Conget

2002-01-01

314

Simultaneous determination of uric acid metabolites allantoin, 6-aminouracil, and triuret in human urine using liquid chromatography–mass spectrometry  

Microsoft Academic Search

Uric acid (UA) can be directly converted to allantoin enzymatically by uricase in most mammals except humans or by reaction with superoxide. UA can react directly with nitric oxide to generate 6-aminouracil and with peroxynitrite to yield triuret; both of these metabolites have been identified in biological samples. We now report a validated high-performance liquid chromatography and tandem mass spectrometry

Kyung Mee Kim; George N. Henderson; Reginald F. Frye; Cheryl D. Galloway; Nancy J. Brown; Mark S. Segal; Witcha Imaram; Alexander Angerhofer; Richard J. Johnson

2009-01-01

315

Intake of Added Sugar and Sugar-Sweetened Drink and Serum Uric Acid Concentration in US Men and Women  

Technology Transfer Automated Retrieval System (TEKTRAN)

Fructose-induced hyperuricemia might have a causal role in metabolic syndrome, hypertension, and other chronic disease. However, no study has investigated whether sugar added to foods or sugar-sweetened beverages, which are major sources of fructose, are associated with serum uric acid concentration...

316

Genome-wide association analysis confirms and extends the association of SLC2A9 with serum uric acid levels to Mexican Americans  

PubMed Central

Increased serum uric acid (SUA) is a risk factor for gout and renal and cardiovascular disease (CVD). The purpose of this study was to identify genetic factors that affect the variation in SUA in 632 Mexican Americans participants of the San Antonio Family Heart Study (SAFHS). A genome-wide association (GWA) analysis was performed using the Illumina Human Hap 550K single nucleotide polymorphism (SNP) microarray. We used a linear regression-based association test under an additive model of allelic effect, while accounting for non-independence among family members via a kinship variance component. All analyses were performed in the software package SOLAR. SNPs rs6832439, rs13131257, and rs737267 in solute carrier protein 2 family, member 9 (SLC2A9) were associated with SUA at genome-wide significance (p < 1.3 × 10?7). The minor alleles of these SNPs had frequencies of 36.2, 36.2, and 38.2%, respectively, and were associated with decreasing SUA levels. All of these SNPs were located in introns 3–7 of SLC2A9, the location of the previously reported associations in European populations. When analyzed for association with cardiovascular-renal disease risk factors, conditional on SLC2A9 SNPs strongly associated with SUA, significant associations were found for SLC2A9 SNPs with BMI, body weight, and waist circumference (p < 1.4 × 10?3) and suggestive associations with albumin-creatinine ratio and total antioxidant status (TAS). The SLC2A9 gene encodes an urate transporter that has considerable influence on variation in SUA. In addition to the primary association locus, suggestive evidence (p < 1.9 × 10?6) for joint linkage/association (JLA) was found at a previously-reported urate quantitative trait locus (Logarithm of odds score = 3.6) on 3p26.3. In summary, our GWAS extends and confirms the association of SLC2A9 with SUA for the first time in a Mexican American cohort and also shows for the first time its association with cardiovascular-renal disease risk factors. PMID:24379826

Voruganti, Venkata Saroja; Kent, Jack W.; Debnath, Subrata; Cole, Shelley A.; Haack, Karin; Göring, Harald H. H.; Carless, Melanie A.; Curran, Joanne E.; Johnson, Matthew P.; Almasy, Laura; Dyer, Thomas D.; MacCluer, Jean W.; Moses, Eric K.; Abboud, Hanna E.; Mahaney, Michael C.; Blangero, John; Comuzzie, Anthony G.

2013-01-01

317

The relationship between uric acid and its oxidative product allantoin: a potential indicator for the evaluation of oxidative stress in birds.  

PubMed

Uric acid is the main nitrogenous waste product in birds but it is also known to be a potent antioxidant. Hominoid primates and birds lack the enzyme urate oxidase, which oxidizes uric acid to allantoin. Consequently, the presence of allantoin in their plasma results from non-enzymatic oxidation. In humans, the allantoin to uric acid ratio in plasma increases during oxidative stress, thus this ratio has been suggested to be an in vivo marker for oxidative stress in humans. We measured the concentrations of uric acid and allantoin in the plasma and ureteral urine of white-crowned sparrows (Zonotrichia leucophrys gambelii) at rest, immediately after 30 min of exercise in a hop/hover wheel, and after 1 h of recovery. The plasma allantoin concentration and the allantoin to uric acid ratio did not increase during exercise but we found a positive relationship between the concentrations of uric acid and allantoin in the plasma and in the ureteral urine in the three activity phases. In the plasma, the slope of the regression describing the above positive relationships was significantly higher immediately after activity. We suggest that the slope indicates the rate of uric acid oxidation and that during activity this rate increases as a result of higher production of free radicals. The present study demonstrates that allantoin is present in the plasma and in the ureteral urine of white-crowned sparrows and therefore might be useful as an indicator of oxidative stress in birds. PMID:16705445

Tsahar, Ella; Arad, Zeev; Izhaki, Ido; Guglielmo, Christopher G

2006-09-01

318

CONTROL OF DIESEL ENGINE UREA SELECTIVE CATALYTIC REDUCTION SYSTEMS.  

E-print Network

??A systematic nonlinear control methodology for urea-SCR systems applicable for light-to-heavy-duty Diesel engine platforms in a variety of on-road, off-road, and marine applications is developed… (more)

Hsieh, Ming-Feng

2010-01-01

319

21 CFR 862.1770 - Urea nitrogen test system.  

Code of Federal Regulations, 2012 CFR

...DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1770 Urea nitrogen test system. (a) Identification....

2012-04-01

320

IRIS TOXICOLOGICAL REVIEW OF UREA (EXTERNAL REVIEW DRAFT)  

EPA Science Inventory

EPA is conducting a peer review and public comment of the scientific basis supporting the human health hazard and dose-response assessment of Urea that when finalized will appear on the Integrated Risk Information System (IRIS) database. ...

321

Microdetermination of urea in urine using p-dimethylaminobenzaldehyde /PDAB/  

NASA Technical Reports Server (NTRS)

Adaptation of the p-dimethylaminobenzaldehyde method for determining urea concentration in urine is an improved micromechanical method. Accuracy and precision are satisfactory. This method avoids extra steps of deproteinizing or removing normal urinary chromogens.

Geiger, P. J.

1969-01-01

322

IRIS Toxicological Review of Urea (Interagency Science Discussion Draft)  

EPA Science Inventory

EPA is releasing the draft report, Toxicological Review of Urea, , that was distributed to Federal agencies and White House Offices for comment during the Science Discussion step of the IRIS Assessment Development Process. C...

323

Hydrogen production via urea electrolysis using a gel electrolyte  

NASA Astrophysics Data System (ADS)

A technology was demonstrated for the production of hydrogen and other valuable products (nitrogen and clean water) through the electrochemical oxidation of urea in alkaline media. In addition, this process remediates toxic nitrates and prevents gaseous ammonia emissions. Improvements to urea electrolysis were made through replacement of aqueous KOH electrolyte with a poly(acrylic acid) gel electrolyte. A small volume of poly(acrylic acid) gel electrolyte was used to accomplish the electrochemical oxidation of urea improving on the previous requirement for large amounts of aqueous potassium hydroxide. The effect of gel composition was investigated by varying polymer content and KOH concentrations within the polymer matrix in order to determine which is the most advantageous for the electrochemical oxidation of urea and production of hydrogen.

King, Rebecca L.; Botte, Gerardine G.

2011-03-01

324

Reinvestigation of growth of thiourea urea zinc sulfate crystal  

NASA Astrophysics Data System (ADS)

Reinvestigation of the growth of thiourea urea zinc sulfate crystal is reported. Aqueous reaction of thiourea, urea and zinc sulfate in 1:1:1 mol ratio results in the formation of the well known [Zn(tu)3(SO4)] (1) (tu = thiourea) crystal and not the 'so called' novel semiorganic nonlinear optical thiourea urea zinc sulfate (2) crystal, as claimed by Redrothu Hanumantha Rao, S. Kalainathan, Spectroscopic investigation, nucleation, growth, optical, thermal and second harmonic studies of novel semi-organic nonlinear optical crystal - Thiourea urea zinc sulfate, Spectrochim. Acta A97 (2012) 456-463. In this work, we demonstrate the usefulness of elemental analytical data, infrared and NMR spectra and X-ray powder pattern, for accurate product characterization.

Srinivasan, Bikshandarkoil R.; Naik, Teja A.; Tylczy?ski, Zbigniew; Priolkar, K. R.

2014-01-01

325

Correcting Nitrogen Deficiencies in Cotton with Urea-Based Products  

E-print Network

Correcting nitrogen deficiency is important for cotton plant growth. This publication explains nitrogen requirements, the problems associated with nitrogen deficiency, and ways to correct deficiencies using urea as a source of nitrogen....

Livingston, Stephen; Stichler, Charles

1995-11-22

326

Solid-state urea biosensor based on the differential method  

Microsoft Academic Search

In this paper, the solid-state urea biosensor was successfully fabricated based on the differential method, which contains three parts: the SnO2\\/ITO glass electrode used as the pseudoreference electrode; the SnO2\\/ITO glass electrode used as the contrast electrode; and the urease\\/SnO2\\/ITO glass electrode used as the enzyme electrode. Correspondingly, this solid-state urea biosensor was fabricated based on the SnO2\\/ITO glass electrode,

Chung-We Pan; Jung-Chuan Chou; Tai-Ping Sun; Shen-Kan Hsiung

2006-01-01

327

Comparison of Uric Acid Quantity with Different Food in Human Urine by Flow Injection Chemiluminescence Analysis  

PubMed Central

Based on the inhibitory effect of uric acid (UA) on luminol-Co2+ chemiluminescence (CL) system, a sensitive method for the determination of UA at nanomolar level by flow injection (FI) CL was proposed. The proposed method was successfully applied to real-time monitoring of UA excretion in human 24?h urine with different food intake, showing that meats, vegetables, and porridge intake caused differential UA excretions of 879, 798, and 742?mg, respectively. It was also found that UA concentrations in urine under the three kinds of food intake simultaneously reached maximum at 2?h after meals with the values of 417, 318, and 288??g?mL?1, respectively. The UA concentration in human serum was also determined by this approach, and the possible mechanism of luminol-Co2+-UA?CL reaction was discussed in detail. PMID:24251067

Wang, Jiajia; Tan, Xijuan; Song, Zhenghua

2013-01-01

328

Uric acid, joint morbidity, and streptococcal antibodies in Maori and European teenagers. Rotorua Lakes study 3.  

PubMed Central

Two hundred and ninety-four New Zealand secondary school students were examined by questionnaire, and physical and biochemical methods. The sample contained almost equal numbers of Maoris and Europeans. The findings related to joint conditions are presented. Past injury and rheumatic disease accounted for some of the reported morbidity, but no important sex or race differences in these factors emerged. There were, however, significant differences in serum uric acid levels with the Maori having higher levels than the Europeans. A significant correlation with body mass was present in both race and sex groups but a correlation with haemoglobin was present only in the European females. While hyperuricaemia was not associated with morbidity in this young sample, ethnic differences anticipated the higher prevalence of gout already observed in Maori men. PMID:1190855

Stanhope, J M; Prior, I A

1975-01-01

329

Serum uric acid and disorders of glucose metabolism: the role of glycosuria  

PubMed Central

Hyperuricemia has been associated with hypertension, diabetes mellitus, and metabolic syndrome. We studied the association between hyperuricemia and glycemic status in a nonrandomized sample of primary care patients. This was a cross-sectional study of adults ?20 years old who were members of a community-based health care program. Hyperuricemia was defined as a value >7.0 mg/dL for men and >6.0 mg/dL for women. The sample comprised 720 participants including controls (n=257) and patients who were hypertensive and euglycemic (n=118), prediabetic (n=222), or diabetic (n=123). The mean age was 42.4±12.5 years, 45% were male, and 30% were white. The prevalence of hyperuricemia increased from controls (3.9%) to euglycemic hypertension (7.6%) and prediabetic state (14.0%), with values in prediabetic patients being statistically different from controls. Overall, diabetic patients had an 11.4% prevalence of hyperuricemia, which was also statistically different from controls. Of note, diabetic subjects with glycosuria, who represented 24% of the diabetic participants, had a null prevalence of hyperuricemia, and statistically higher values for fractional excretion of uric acid, Na excretion index, and prevalence of microalbuminuria than those without glycosuria. Participants who were prediabetic or diabetic but without glycosuria had a similarly elevated prevalence of hyperuricemia. In contrast, diabetic patients with glycosuria had a null prevalence of hyperuricemia and excreted more uric acid and Na than diabetic subjects without glycosuria. The findings can be explained by enhanced proximal tubule reabsorption early in the course of dysglycemia that decreases with the ensuing glycosuria at the late stage of the disorder. PMID:25250631

Andrade, J.A.M.; Kang, H.C.; Greffin, S.; Garcia Rosa, M.L.; Lugon, J.R.

2014-01-01

330

Serum uric acid and disorders of glucose metabolism: the role of glycosuria.  

PubMed

Hyperuricemia has been associated with hypertension, diabetes mellitus, and metabolic syndrome. We studied the association between hyperuricemia and glycemic status in a nonrandomized sample of primary care patients. This was a cross-sectional study of adults ? 20 years old who were members of a community-based health care program. Hyperuricemia was defined as a value >7.0 mg/dL for men and >6.0 mg/dL for women. The sample comprised 720 participants including controls (n=257) and patients who were hypertensive and euglycemic (n=118), prediabetic (n=222), or diabetic (n=123). The mean age was 42.4 ± 12.5 years, 45% were male, and 30% were white. The prevalence of hyperuricemia increased from controls (3.9%) to euglycemic hypertension (7.6%) and prediabetic state (14.0%), with values in prediabetic patients being statistically different from controls. Overall, diabetic patients had an 11.4% prevalence of hyperuricemia, which was also statistically different from controls. Of note, diabetic subjects with glycosuria, who represented 24% of the diabetic participants, had a null prevalence of hyperuricemia, and statistically higher values for fractional excretion of uric acid, Na excretion index, and prevalence of microalbuminuria than those without glycosuria. Participants who were prediabetic or diabetic but without glycosuria had a similarly elevated prevalence of hyperuricemia. In contrast, diabetic patients with glycosuria had a null prevalence of hyperuricemia and excreted more uric acid and Na than diabetic subjects without glycosuria. The findings can be explained by enhanced proximal tubule reabsorption early in the course of dysglycemia that decreases with the ensuing glycosuria at the late stage of the disorder. PMID:25250631

Andrade, J A M; Kang, H C; Greffin, S; Garcia Rosa, M L; Lugon, J R

2014-10-01

331

Uric formaldehyde levels are negatively correlated with cognitive abilities in healthy older adults.  

PubMed

Recent studies have shown that the abnormal accumulation of endogenous formaldehyde could be a critical factor in age-related cognitive decline. The aim of this study was to estimate the correlation between uric formaldehyde and general cognitive abilities in a community-based elderly population, and to measure the extent and direction in which the correlation varied with demographic characteristics. Using a double-blind design, formaldehyde in human urine was analyzed by high-performance liquid chromatography (n = 604), and general cognitive abilities were measured using the Montreal Cognitive Assessment (MoCA). Demographic characteristics, in terms of age, gender, residential region, and education were taken into consideration. We found that uric formaldehyde levels were inversely correlated with the MoCA score, and the concentration varied with demographic features: higher odds of a high formaldehyde level occurred among the less educated and those living in old urban or rural areas. In cytological experiments, the level of cellular formaldehyde released into the medium increased as SH-SY5Y and BV2 cells were incubated for three days. Formaldehyde in excess impaired the processes of N2a cells and neurites of primary cultured rat hippocampal cells. However, removal of formaldehyde markedly rescued and regenerated the processes of N2a cells. These results demonstrated a negative correlation between the endogenous formaldehyde and general cognitive abilities. High formaldehyde levels could be a risk factor for cognitive impairment in older adults, and could be developed as a non-invasive marker for detection and monitoring of age-related cognitive impairment. PMID:24733650

Yu, Jing; Su, Tao; Zhou, Ting; He, Yingge; Lu, Jing; Li, Juan; He, Rongqiao

2014-04-01

332

Potent human uric acid transporter 1 inhibitors: in vitro and in vivo metabolism and pharmacokinetic studies  

PubMed Central

Human uric acid transporter 1 (hURAT1; SLC22A12) is a very important urate anion exchanger. Elevated urate levels are known to play a pivotal role in cardiovascular diseases, chronic renal disease, diabetes, and hypertension. Therefore, the development of potent uric acid transport inhibitors may lead to novel therapeutic agents to combat these human diseases. The current study investigates small molecular weight compounds and their ability to inhibit 14C-urate uptake in oocytes expressing hURAT1. Using the most promising drug candidates generated from our structure–activity relationship findings, we subsequently conducted in vitro hepatic metabolism and pharmacokinetic (PK) studies in male Sprague-Dawley rats. Compounds were incubated with rat liver microsomes containing cofactors nicotinamide adenine dinucleotide phosphate and uridine 5?-diphosphoglucuronic acid. In vitro metabolism and PK samples were analyzed using liquid chromatography/mass spectrometry-mass spectrometry methods. Independently, six different inhibitors were orally (capsule dosing) or intravenously (orbital sinus) administered to fasting male Sprague-Dawley rats. Blood samples were collected and analyzed; these data were used to compare in vitro and in vivo metabolism and to compute noncompartmental model PK values. Mono-oxidation (Phase I) and glucuronidation (Phase II) pathways were observed in vitro and in vivo. The in vitro data were used to compute hepatic intrinsic clearance, and the in vivo data were used to compute peak blood concentration, time after administration to achieve peak blood concentration, area under the curve, and orally absorbed fraction. The experimental data provide additional insight into the hURAT1 inhibitor structure–activity relationship and in vitro–in vivo correlation. Furthermore, the results illustrate that one may successfully prepare potent inhibitors that exhibit moderate to good oral bioavailability. PMID:23152669

Wempe, Michael F; Lightner, Janet W; Miller, Bettina; Iwen, Timothy J; Rice, Peter J; Wakui, Shin; Anzai, Naohiko; Jutabha, Promsuk; Endou, Hitoshi

2012-01-01

333

Analysis of the Sub-Millimeter Rotational Spectrum of Urea  

NASA Astrophysics Data System (ADS)

Urea, ((NH_{2})_{2}CO), has broad presence in biological species. As a byproduct of human metabolism, this molecule is commonly tested for in blood to diagnose different pathologies. Furthermore, urea is seen in interstellar medium and its detection could yield valuable insight into the mechanisms governing star formation. Despite the prevalence of urea, an absence exists in recorded frequencies of this molecule. The new generation of the sub-millimeter telescopes, such as ALMA, HERSCHEL, and SOFIA, allows detection of interstellar molecular spectra at unprecedented spatial and spectral resolutions. The knowledge of the precise frequencies of spectra transitions present in interstellar molecular clouds would alleviate the problem of spectral congestion and aid in molecular identification. This paper reports the most recent investigation of the submillimeter/terahertz gas phase spectrum of urea. Up until now, only the microwave laboratory spectrum of urea's vibrational ground state has been available. This paper reports the high-resolution spectra of urea in the sub-millimeter range, and extends the spectroscopic assignment of the rotational transitions in the vibrational ground state. Additionally, the assignment of the first vibrational state and tentative assignments of two additional vibrational states have been made.

Thomas, Jessica R.; Fosnight, Alyssa M.; Medvedev, Ivan R.

2013-06-01

334

Serum cystatin C measured by automated immunoassay: A more sensitive marker of changes in GFR than serum creatinine  

Microsoft Academic Search

Serum cystatin C measured by automated immunoassay: A more sensitive marker of changes in GFR than serum creatinine. Serum cystatin C has been suggested as a new marker of GFR. For the introduction of this marker into clinical use a rapid and automated method is required. We have developed and validated an assay for serum cystatin C using latex particle-enhanced

David J Newman; Hansa Thakkar; Robert G Edwards; Martin Wilkie; Thomas White; Anders O Grubb; Christopher P Price

1995-01-01

335

Serum cystatin C is superior to serum creatinine as a marker of kidney function: A meta-analysis  

Microsoft Academic Search

Background: Serum cystatin C (Cys C) has been proposed as a simple, accurate, and rapid endogenous marker of glomerular filtration rate (GFR) in research and clinical practice. However, there are conflicting reports regarding the superiority of Cys C over serum creatinine (Cr), with a few studies suggesting no significant difference. Methods: We performed a meta-analysis of available data from various

Vikas R. Dharnidharka; Charles Kwon; Gary Stevens

2002-01-01

336

Using Serum Creatinine To Estimate Glomerular Filtration Rate: Accuracy in Good Health and in Chronic Kidney Disease  

Microsoft Academic Search

Background: The National Kidney Foundation has advocated the use of the abbreviated Modification of Diet in Renal Disease (MDRD) equation to estimate glomerular filtration rate (GFR) from serum creatinine measurements in clinical laboratories. However, healthy persons were not included in the development of the MDRD equation. Objectives: To assess the accuracy of the MDRD equation in patients with chronic kidney

Andrew D. Rule; Timothy S. Larson; Erik J. Bergstralh; Jeff M. Slezak; Steven J. Jacobsen; Fernando G. Cosio

2004-01-01

337

Tandem measurements of iron and creatinine by cross injection analysis with application to urine from thalassemic patients.  

PubMed

This work presents development of a method for the dual determination of Fe(III) and creatinine using cross injection analysis (CIA). Two CIA platforms connected in series accommodated sample and reagents plugs aspirated via y-direction channels while water was pumped through the x-direction channel toward a flow-through cell of a diode array UV-vis. detector. Iron was detected from the colorimetric reaction between Fe(II) and 2-(5-bromo-2-pyridylazo)-5-(N-propyl-N-(3-sulfopropyl)amino) aniline (5-Br-PSAA), with prior reduction of Fe(III) to Fe(II) by ascorbic acid. The Jaffe's reaction was employed for the detection of creatinine. Under the optimal conditions, good linearity ranges were achieved for iron in the range 0.5 to 7 mg L(-1) and creatinine in the range 50 to 800 mg L(-1). The CIA system was applied to spot urine samples from thalassemic patients undergoing iron chelation therapy, and was successfully validated with ICP-OES and batchwise Jaffe's method. Normalization of urinary iron excretion with creatinine is useful for correcting the iron concentration between urine samples due to variation of the collected urine volume. PMID:25435226

Choengchan, N; Mantim, T; Inpota, P; Nacapricha, D; Wilairat, P; Jittangprasert, P; Waiyawat, W; Fucharoen, S; Sirankpracha, P; Morales, N Phumala

2015-02-01

338

[Simultaneous determination of melamine and creatinine in milk and milk products by gas chromatography-mass spectrometry].  

PubMed

A method established for determining melamine and creatinine in milk and milk products. The samples were extracted with 1% trichloracetic acid solution. The extract was cleaned-up by using a mixed-mode cation ion exchange SPE column and evaporated to dryness under nitrogen. The residue was derived by bis (trimethylsilyl) trifluoroacetamide-chlorotrimethylsilane (BSTFA-TMCS), then determined by gas chromatography-mass spectrometry (GC-MS) in selected ion monitoring (SIM) mode. Melamine and creatinine had good linearity in the range of 0.1 - 50 mg/L with the correlation coefficients higher than 0.99, and the limits of quantification were 0.10 mg/kg and 0.20 mg/kg, respectively. The recoveries of melamine and creatinine were 80.7% - 116.8% and 77.6% - 107.5% with RSD no more than 9.4% and 8.5% in the spiked range of 10 - 100 mg/kg and 0.1 - 5.0 mg/kg, respectively. The method is accurate, sensitive, and suitable for the determination of creatinine in milk and milk products. PMID:24010350

Zeng, Kai; Liu, Zhirong; Ning, Yajun; Li, Jinlin; Tang, Jun; Zhang, Min

2013-05-01

339

Limitations of Early Serum Creatinine Variations for the Assessment of Kidney Injury in Neonates and Infants with Cardiac Surgery  

PubMed Central

Background Changes in kidney function, as assessed by early and even small variations in serum creatinine (?sCr), affect survival in adults following cardiac surgery but such associations have not been reported in infants. This raises the question of the adequate assessment of kidney function by early ?sCr in infants undergoing cardiac surgery. Methodology The ability of ?sCr within 2 days of surgery to assess the severity of kidney injury, accounted for by the risk of 30-day mortality, was explored retrospectively in 1019 consecutive neonates and infants. Patients aged ? 10 days were analyzed separately because of the physiological improvement in glomerular filtration early after birth. The Kml algorithm, an implementation of k-means for longitudinal data, was used to describe creatinine kinetics, and the receiver operating characteristic and the reclassification methodology to assess discrimination and the predictive ability of the risk of death. Results Three clusters of ?sCr were identified: in 50% of all patients creatinine decreased, in 41.4% it increased slightly, and in 8.6% it rose abruptly. Mortality rates were not significantly different between the first and second clusters, 1.6% [0.0–4.1] vs 5.9% [1.9–10.9], respectively, in patients aged ? 10 days, and 1.6% [0.5–3.0] vs 3.8% [1.9–6.0] in older ones. Mortality rates were significantly higher when creatinine rose abruptly, 30.3% [15.1–46.2] in patients aged ? 10 days, and 15.1% [5.9–25.5] in older ones. However, only 41.3% of all patients who died had an abrupt increase in creatinine. ?sCr improved prediction in survivors, but not in patients who died, and did not improve discrimination over a clinical mortality model. Conclusions The present results suggest that a postoperative decrease in creatinine represents the normal course in neonates and infants with cardiac surgery, and that early creatinine variations lack sensitivity for the assessment of the severity of kidney injury. PMID:24244476

Bojan, Mirela; Lopez-Lopez, Vanessa; Pouard, Philippe; Falissard, Bruno; Journois, Didier

2013-01-01

340

Application of creatinine- and/or cystatin C-based glomerular filtration rate estimation equations in elderly Chinese  

PubMed Central

Background No conventional creatinine- or cystatin C-based glomerular filtration rate (GFR) estimation equation performed consistently outstandingly in elderly Chinese in our previous studies. This research aimed to further evaluate the performance of some recently proposed estimation equations based on creatinine and cystatin C, alone or combined, in this specific population. Materials and methods The equations were validated in a population totaling 419 participants (median age 68 [range 60–94] years). The estimated GFR (eGFR) calculated separately by ten equations was compared with the reference GFR (rGFR) measured by the 99mTc-DTPA renal dynamic imaging method. Results Median serum creatinine, cystatin C, and rGFR levels were 0.93 mg/L, 1.13 mg/L, and 74.20 mL/min/1.73 m2, respectively. The Chinese population-developed creatinine- and cystatin C-based (Cscr-cys) equation yielded the least median absolute difference (8.81 vs range 9.53–16.32, P<0.05, vs the Chronic Kidney Disease Epidemiology Collaboration serum creatinine equation), the highest proportion of eGFR within 15% and 30% of rGFR (P15 and P30, 55.13 and 85.44, P<0.05 and P<0.01, vs the Chronic Kidney Disease Epidemiology Collaboration serum creatinine equation), and the lowest root mean square error (14.87 vs range 15.30–22.45) in the whole cohort. A substantial agreement of diagnostic consistency between eGFR and rGFR (with a kappa 0.61–0.80) was also observed with the Cscr-cys equation. Moreover, measures of performance in the Cscr-cys equation were consistent across normal to mildly injured GFR strata and individuals aged ?80 years. Among all the Cscr-cys equations, the elderly Chinese-developed creatinine-based (CEscr) equation performed best in this specific population. Nevertheless, none of the equations achieved ideal manifestation in the moderately to severely GFR-injured group or in individuals aged ?80 years. Conclusion The Cscr-cys equation appeared to be optimal in elderly Chinese among the investigated equations. If cystatin C is not available, the CEscr equation is an acceptable alternative. A multicenter study with abundant subjects to develop an apposite formula for elderly Chinese is assumed to be essential. PMID:25246780

Ye, Xiaoshuang; Wei, Lu; Pei, Xiaohua; Zhu, Bei; Wu, Jianqing; Zhao, Weihong

2014-01-01

341

Diurnal Variation of Rumen Ammonia, Serum Urea, and Milk Urea in Dairy Cows at High and Low Yields1  

Microsoft Academic Search

ABSTRACT Milk urea content as an indicator of nutritional status may,be a useful tool if major,sources of variation are consid- ered. Blood and milk samples were col- lected frequently during 16 to 19 h from four Holstein cows to study diurnal vari- ation of urea content. Corn silage, alfalfa hay, and concentrates were fed. Rumen ammonia, VFA, and pH were

D. L. Palmquist

1993-01-01

342

Detection of decreased glomerular filtration rate in intensive care units: serum cystatin C versus serum creatinine  

PubMed Central

Background Detecting impaired glomerular filtration rate (GFR) is important in intensive care units (ICU) in order to diagnose acute kidney injuries and adjust the dose of renally excreted drugs. Whether serum Cystatin C (SCysC) may better reflect glomerular filtration rate than serum creatinine (SCr) in the context of intensive care medicine is uncertain. Methods We compared the performance of SCysC and SCr as biomarkers of GFR in 47 critically ill patients (median SOFA (Sepsis-related Organ Failure Assessment) score of 5) for whom GFR was measured by a reference method (urinary clearance of iohexol). Results Mean Iohexol clearance averaged 96?±?54 mL/min and was under 60 mL/min in 28% of patients. Mean SCr and SCysC concentrations were 0.70?±?0.33 mg/dL and 1.26?±?0.61 mg/L, respectively. Area under the ROC curve for a GFR threshold of 60 mL/min was 0.799 and 0.942 for SCr and SCysC, respectively (p = 0.014). Conclusions We conclude that ScysC significantly outperfoms SCr for the detection of an impaired GFR in critically ill patients. Trial registration ClinicalTrials.gov: B7072006347 PMID:24410757

2014-01-01

343

The Effect of Hibiscus Sabdariffa on Lipid Profile, Creatinine, and Serum Electrolytes: A Randomized Clinical Trial  

PubMed Central

Background. Hibiscus Sabdariffa L. (HS), a member of malvaceae family, is a medicinal plant with a worldwide fame. Its effect on reducing serum lipids is mentioned in several studies. The purpose of this study was to assess the efficacy of this plant in reducing the serum's lipids in hypertensive patients. Materials and Methods. Ninety hypertensive patients were randomly assigned to receive Hibiscus Sabdariffa (HS) tea or black tea for 15 days. The patients were asked to drink the tea within 20 minutes following its preparation. This process had to be repeated two times, daily. Patient's FBS and lipid profile were collected at the first visit day (day 0) and on the day 30. Results. There was no significant differences between pre and post experiment values within the two groups. An upward trend in total cholesterol, HDL, and LDL cholesterol was evident in both groups. The increase in total and HDL cholesterol in both groups relative to their initial values were significant. Conclusion. Hibiscus Sabdariffa is probably a safe medicinal plant. No significant harmful changes in cholesterol, triglyceride, BUN, serum creatinine, Na and K levels were observed within 15 days after the discontinuation of the medication. PMID:21991538

Mohagheghi, Abbas; Maghsoud, Shirin; Khashayar, Patricia; Ghazi-Khansari, Mohammad

2011-01-01

344

Plasma exogenous creatinine excretion for the assessment of renal function in avian medicine--pharmacokinetic modeling in racing pigeons (Columba livia).  

PubMed

The diagnostic evaluation of the glomerular filtration rate by urinary clearance has significant practical limitations in birds because urine is excreted together with feces. Thus, pharmacokinetic modeling of an exogenous plasma creatinine clearance could be useful for assessing renal creatinine excretion in birds. For this study, creatinine (50 mg/kg) was administered to 2 groups of 15 pigeons (Columba livia) each; in one group by the intravenous (IV) route and in the second by the intramuscular (IM) route. The time series of the plasma creatinine concentrations were analyzed by pharmacokinetic models. Body mass-specific creatinine excretion was determined for IV and IM administration to be between 6.30 and 6.44 mL/min per kg, respectively. Body surface area-specific creatinine clearance, which is related to the metabolic rate, was calculated between 0.506 and 0.523 mL/min per dm2, respectively. The results showed that IV as well as IM administration can be used for assessing renal creatinine excretion in pigeons. For practical reasons, IM administration is recommended, with the use of the Bateman function to calculate creatinine elimination. PMID:24344507

Scope, Alexandra; Schwendenwein, Ilse; Schauberger, Günther

2013-09-01

345

A simple and sensitive fluorescence based biosensor for the determination of uric acid using H2O2-sensitive quantum dots/dual enzymes.  

PubMed

A novel optical detection system consisting of combination of uricase/HRP-CdS quantum dots (QDs) for the determination of uric acid in urine sample is described. The QDs was used as an indicator to reveal fluorescence property of the system resulting from enzymatic reaction of uricase and HRP (horseradish peroxidase), which is involved in oxidizing uric acid to allaintoin and hydrogen peroxide. The hydrogen peroxide produced was able to quench the QDs fluorescence, which was proportional to uric acid concentration. The system demonstrated sufficient activity of uricase and HRP at a ratio of 5U:5U and pH 7.0. The linearity of the system toward uric acid was in the concentration range of 125-1000µM with detection limit of 125µM. PMID:25113659

Azmi, Nur Ellina; Ramli, Noor Izaanin; Abdullah, Jaafar; Abdul Hamid, Mohammad Azmi; Sidek, Hamidah; Abd Rahman, Samsulida; Ariffin, Nurhayati; Yusof, Nor Azah

2015-05-15

346

Crystal structure of a bacterial homologue of the kidney urea transporter  

SciTech Connect

Urea is highly concentrated in the mammalian kidney to produce the osmotic gradient necessary for water re-absorption. Free diffusion of urea across cell membranes is slow owing to its high polarity, and specialized urea transporters have evolved to achieve rapid and selective urea permeation. Here we present the 2.3 {angstrom} structure of a functional urea transporter from the bacterium Desulfovibrio vulgaris. The transporter is a homotrimer, and each subunit contains a continuous membrane-spanning pore formed by the two homologous halves of the protein. The pore contains a constricted selectivity filter that can accommodate several dehydrated urea molecules in single file. Backbone and side-chain oxygen atoms provide continuous coordination of urea as it progresses through the filter, and well-placed {alpha}-helix dipoles provide further compensation for dehydration energy. These results establish that the urea transporter operates by a channel-like mechanism and reveal the physical and chemical basis of urea selectivity.

Levin, Elena J.; Quick, Matthias; Zhou, Ming; (Columbia)

2010-03-19

347

Hypoxanthine, Uric Acid and Allantoin as Indicators of in Vivo Free Radical Reactions. Description of a HPLC Method and Human Brain Microdialysis Data  

Microsoft Academic Search

Summary  ¶?A practical one-step high performance liquid chromatography (HPLC) method was developed for the simultaneous determination\\u000a of hypoxanthine, uric acid and allantoin in small (4 ?L) microdialysis samples. The rationale for this work was the current\\u000a interest in hypoxanthine as a marker for energy perturbation in hypoxia\\/ischemia, in uric acid as an endogenous antioxidant,\\u000a and in allantoin as a marker for

N. Marklund; B. Östman; L. Nalmo; L. Persson; L. Hillered

2000-01-01

348

Ammonium assimilation in Proteus vulgaris, Bacillus pasteurii, and Sporosarcina ureae.  

PubMed

No active uptake of ammonium was detected in Proteus vulgaris, Bacillus pasteurii, and Sporosarcina ureae, which indicates that these bacteria depend on the passive diffusion of ammonia across the cell membrane. In P. vulgaris the glutamine synthetase-glutamate synthase (GS-GOGAT) pathway and glutamate dehydrogenase (GDH) were present, and these enzymes exhibited high affinities for ammonium. In B. pasteurii and S. ureae, however, no GS activity was detected, and GOGAT activity was only present in S. ureae. GDH enzymes were present in these two organisms, but showed only low affinity for ammonium, with apparent Km-values of 55.2 mM in B. pasteurii and 36.7 mM in S. ureae, respectively. These observations explain why P. vulgaris is able to grow at neutral pH and low ammonium concentration (2 mM), while B. pasteurii and S. ureae require high ammonium concentration (40 mM) and alkaline pH for growth. PMID:2570557

Mörsdorf, G; Kaltwasser, H

1989-01-01

349

Effect of creatine, creatinine, and creatine ethyl ester on TLR expression in macrophages  

PubMed Central

Despite the widespread availability and use of dietary supplements, minimal work has been performed to assess the potential dangers many of these supplements may have on the host’s well-being, in particular the host’s ability to respond to infection. One supplement extensively used by both adolescents and adults is creatine. Using Real-time PCR, we examined the impact of short-term exposure of a mouse macrophage cell line (RAW 264.7 cells) to two readily available forms of creatine used in supplements – creatine monohydrate (CR) and creatine ethyl ester (CEE) as well as the end product of creatine metabolism, creatinine (CRN), on expression of toll-like receptor-2 (TLR-2), TLR-3, TLR-4, and TLR-7. CR down-regulated TLR-2, TLR-3, TLR-4 and TLR-7 mRNA levels in RAW cells. Similar results were observed following exposure of RAW cells to CRN. Conversely CEE appears to possess immunostimulatory properties and increases expression of TLR-2, TLR-3, TLR-4, and TLR-7 in RAW cells. These data are supported by immunostaining using antibodies specific for the individual TLRs before and after exposure of RAW cells to CR, CRN, or CEE. To extend these findings, we isolated murine splenocytes and exposed the cells to CR, CEE, or CRN for 24 hours and performed immunofluorescent staining for TLR-2, TLR-3, TLR-4 and TLR-7. The results obtained from this study with primary splenocytes were consistent with the studies using RAW cells. Together, these data suggest that creatine and creatine derivatives may impact the ability of immune cells to sense a wide array of viral and bacterial pathogens. Of great interest, CRN - largely considered to be a waste product of the argenine biosynthesis pathway may also have immunosuppressive properties similar to those of CR. PMID:21575742

Leland, Korey M.; McDonald, Thomas L.; Drescher, Kristen M.

2011-01-01

350

Effects on milk urea concentration, urine output, and drinking water intake from incremental doses of potassium bicarbonate fed to mid-lactation dairy cows.  

PubMed

Large variation exists in the potassium content of dairy cow feeds and also within a feed type due to soil type and fertilization. Increased ration K concentration causes a subsequent increase in urinary volume and could be expected to also lower milk urea concentration. Six multiparous mid-lactation Swedish Red dairy cows, all fitted with rumen cannulas, were subjected to 3 different levels of K intake in a Latin square experiment with three 2-wk periods to evaluate the effects on concentrations of milk urea and rumen ammonia, urinary output, and drinking water intake. The treatments were achieved by K supplementation on top of a low-K basal ration fed at individual allowances fixed throughout the experiment. The basal ration, consumed at 20.2 kg of dry matter (DM)/d, provided 165 g of crude protein/kg of DM and consisted of grass silage, concentrates, and urea in the proportions 39.3:60.0:0.7 on a DM basis. Potassium bicarbonate supplementation was 0, 616, and 1,142 g/d, respectively, to give total ration K concentrations that were low (LO; 12 g/kg of DM), medium (MED; 23 g/kg of DM), or high (HI; 32 g/kg of DM). Production and composition of milk was not affected by treatment. A linear effect on milk urea concentration was detected, being 4.48, 4.18, and 3.77 mM for LO, MED, and HI, respectively, and a linear tendency for rumen ammonia concentration with 6.65, 6.51, and 5.84 mg of NH?-N/dL for LO, MED, and HI, respectively. Milk urea concentration peaked about 3h after the rumen ammonia peak from the morning feeding, at a level 1.3mM over the baseline. Urinary urea excretion declined linearly (105, 103, and 98 g of urea-N/d for LO, MED, and HI, respectively). Linear increases occurred in urinary output (0.058 ± 0.001 kg of urine/g of K intake; no intercept; coefficient of determination=0.997) and drinking water intake (65.9 ± 2.02 + 0.069 ± 0.004 kg of water/g of K intake; coefficient of determination=0.95). Urinary K concentration leveled off at 12.4 g/L. Urinary creatinine excretion was not affected by K addition, but allantoin excretion increased linearly by 27% from LO to HI, suggesting increased rumen microbial growth. Rumen pH, acetate proportion of total volatile fatty acids, and digestibility of DM, organic matter, and neutral detergent fiber increased linearly with increasing potassium intake. We concluded that increased ration K concentration lowers milk urea concentration with a magnitude significant for the interpretation of milk urea values, but other sources of variation, such as sampling time relative to feeding, may be even more important. PMID:24835966

Eriksson, T; Rustas, B-O

2014-07-01

351

Association between serum uric acid levels and cardiovascular disease in middle-aged and elderly Chinese individuals  

PubMed Central

Background A link between uric acid (UA) levels and cardiovascular diseases has been previously reported. However, its importance as a risk factor is still controversial. This study sought to determine whether elevated serum uric acid levels are associated with cardiovascular disease (CVD) in middle-aged and elderly Chinese individuals. Methods We conducted a population-based cross-sectional study in Shanghai, with a total of 8510 participants aged ?40 years. The CVD included diagnosed coronary heart disease (CHD) and stroke. MetS was defined according to the updated National Cholesterol Education Program Adult Treatment Panel III criteria for Asian Americans. Results Uric acid levels were positively associated with BMI, waist circumference, triglycerides, systolic blood pressure, diastolic blood pressure, glycohemoglobin, fasting plasma glucose, postprandial 2-hour plasma glucose (all P?uric acid level was associated with CVD, independent of conventional cardiovascular disease risk factors and metabolic syndrome. PMID:24568132

2014-01-01

352

Simultaneous determination of tryptophan, uric acid and ascorbic acid at iron(III) doped zeolite modified carbon paste electrode  

Microsoft Academic Search

A new chemically modified electrode is constructed based on iron(III) doped zeolite modified carbon paste electrode (Fe3+Y\\/ZCME). The electrode was evaluated as a sensor for sub-micromolar determination of tryptophan (Trp), uric acid (UA) and ascorbic acid (AA) in aqueous solutions. The measurements were carried out by application of the differential pulse voltammetry (DPV) method in phosphate buffer solution with pH

Ali Babaei; Mojgan Zendehdel; Balal Khalilzadeh; Alireza Taheri

2008-01-01

353

Simultaneous measurement of allantoin, uric acid, xanthine and hypoxanthine in blood by high-performance liquid chromatography  

Microsoft Academic Search

A high-performance liquid chromatographic method for determining catabolism products of nucleic acids and purines, such as oxypurines (i.e. uric acid, xanthine and hypoxanthine) and allantoin in the blood plasma of ruminants was developed. The plasma was deproteinized with 10% trichloroacetic acid. The method enabled determination of oxypurines without derivatization. Allantoin was determined after conversion with 2,4-dinitrophenylhydrazine to a hydrazone (GLX-DNPH).

M Czauderna; J Kowalczyk

1997-01-01

354

Recapture of [S]-allantoin, the product of the two-step degradation of uric acid, by urate oxidase  

Microsoft Academic Search

Urate oxidase from Aspergillus flavus catalyzes the degradation of uric acid to [S]-allantoin through 5-hydroxyisourate as a metastable intermediate. The second degradation step is thought either catalyzed by another specific enzyme, or spontaneous. The structure of the enzyme was known at high resolution by X-ray diffraction of I222 crystals complexed with a purine-type inhibitor (8-azaxanthin). Analyzing the X-ray structure of

Laure Gabison; Mohamed Chiadmi; Nathalie Colloc’h; Bertrand Castro; Mohamed El Hajji; Thierry Prangé

2006-01-01

355

Enzymatic Method for Assaying Uric Acid in Serum with a New Tetrazolium Salt Produces Water-Soluble Formazan Dye  

Microsoft Academic Search

Objectives: To apply an enzymatic method for assaying uric acid in serum based on the uricase (EC 1.7.3.3)-catalase (EC 1.11.1.6)-formaldehyde dehydrogenase (FADH, EC 1.2.1.46) coupled with the new tetrazolium salt producing a water-soluble formazan dye as an indicator system. Unlike the traditional tetrazolium salts, e.g., iodonitrotetrazolium (INT) and nitrotetrazolium blue (NTB), the corresponding formazan dye produced did not absorb to

Yuzo Kayamori; Yoshiaki Katayama; Tatsuo Matsuyama; Takeyoshi Urata

1997-01-01

356

Expression and purification of a functional uric acid-xanthine transporter (UapA).  

PubMed

The Nucleobase-Ascorbate Transporters (NATs) family includes carriers with fundamental functions in uptake of key cellular metabolites, such as uric acid or vitamin C. The best studied example of a NAT transporter is the uric acid-xanthine permease (UapA) from the model ascomycete Aspergillus nidulans. Detailed genetic and biochemical analyses have revealed much about the mechanism of action of this protein; however, the difficulties associated with handling eukaryotic membrane proteins have limited efforts to elucidate the precise structure-function relationships of UapA by structural analysis. In this manuscript, we describe the heterologous overexpression of functional UapA as a fusion with GFP in different strains of Saccharomyces cerevisiae. The UapA-GFP construct expressed to 2.3 mg/L in a pep4Delta deletion strain lacking a key vacuolar endopeptidase and 3.8 mg/L in an npi1-1 mutant strain with defective Rsp5 ubiquitin ligase activity. Epifluorescence microscopy revealed that the UapA-GFP was predominately localized to the plasma membrane in both strains, although a higher intensity of fluorescence was observed for the npi1-1 mutant strain plasma membrane. In agreement with these observations, the npi1-1 mutant strain demonstrated a approximately 5-fold increase in uptake of [(3)H]-xanthine compared to the pep4Delta deletion strain. Despite yielding the best results for functional expression, in-gel fluorescence of the UapA-GFP expressed in the npi1-1 mutant strain revealed that the protein was subject to significant proteolytic degradation. Large scale expression of the protein using the pep4Delta deletion strain followed by purification produced mg quantities of pure, monodispersed protein suitable for further structural and functional studies. In addition, this work has generated a yeast cell based system for performing reverse genetics and other targeted approaches, in order to further understand the mechanism of action of this important model protein. PMID:20153431

Leung, James; Karachaliou, Mayia; Alves, Claudia; Diallinas, George; Byrne, Bernadette

2010-07-01

357

Amperometric uric acid biosensor based on poly(vinylferrocene)-gelatin-carboxylated multiwalled carbon nanotube modified glassy carbon electrode.  

PubMed

In this study, a new uric acid biosensor was constructed based on ferrocene containing polymer poly(vinylferrocene) (PVF), carboxylated multiwalled carbon nanotubes (c-MWCNT) and gelatin (GEL) modified glassy carbon electrode (GCE). Uricase enzyme (UOx) was immobilized covalently through N-ethyl-N'-(3-dimethyaminopropyl) carbodiimide (EDC) and N-hydroxyl succinimide (NHS) chemistry onto c-MWCNT/GEL/PVF/GCE. The c-MWCNT/GEL/PVF composite was characterized by scanning electron microscopy, cyclic voltammetry and electrochemical impedance spectroscopy. Various experimental parameters such as pH, applied potential, enzyme loading, PVF and c-MWCNT concentration were investigated in detail. Under the optimal conditions the dynamic linear range of uric acid was 2.0×10(-7)M-7.1×10(-4)M (R=0.9993) with the detection limit low to 2.3×10(-8)M. With good selectivity and sensitivity, the biosensor was successfully applied to determine the uric acid in human serum. The results of the biosensor were in good agreement with those obtained from standard method. Therefore, the presented biosensor could be a good promise for practical applications in real samples. PMID:25618698

Erden, P?nar Esra; Kaçar, Ceren; Öztürk, Funda; K?l?ç, Esma

2015-03-01

358

Melinjo (Gnetum gnemon L.) Seed Extract Decreases Serum Uric Acid Levels in Nonobese Japanese Males: A Randomized Controlled Study  

PubMed Central

Melinjo (Gnetum gnemon L.) seed extract (MSE) containing trans-resveratrol (3,5,4?-trihydroxy-trans-stilbene) and other derivatives exerts various beneficial effects. However, its mechanism of action in humans remains unknown. In this study, we aimed to investigate beneficial effects of MSE in healthy adult males. In this double-blind, randomized controlled study, 30 males aged 35–70 years with ?10% flow-mediated dilatation received placebo or 750?mg MSE powder for 8 weeks, and twenty-nine males (45.1 ± 8.8 years old) completed the trial. There was a significant difference in the melinjo and placebo groups. Compared with the placebo control, MSE significantly reduced serum uric acid at 4 weeks and 8 weeks (n = 14 and 15, resp.). HDL cholesterol was significantly increased in the melinjo group. To clarify the mechanism of MSE for reducing uric acid, we investigated xanthine oxidase inhibitory activity, angiotensin II type 1 (AT1) receptor binding inhibition rate, and agonistic activities for PPAR? and PPAR?. MSE, trans-resveratrol, and a resveratrol dimer, gnetin C (GC), significantly inhibit AT1 receptor binding and exhibit mild agonistic activities for PPAR? and PPAR?. In conclusion, MSE may decrease serum uric acid regardless of insulin resistance and may improve lipid metabolism by increasing HDL cholesterol. PMID:24454499

Kanai, Yoshiaki; Katagiri, Mikiyuki; Mori, Akemi; Tatefuji, Tomoki

2013-01-01

359

Altered serum selenium and uric acid levels and dyslipidemia in hemodialysis patients could be associated with enhanced cardiovascular risk.  

PubMed

In the present study, the first objective was to follow up serum selenium (Se) concentrations in 117 hemodialysis patients (HPs) during a 2-year longitudinal study, relating concentrations to biochemical indexes (n?=?6; namely lipoprotein profile, uric acid, and total protein levels). It was also evaluated whether the disease is associated with an enhanced cardiovascular risk. A healthy control group (n?=?50) was also studied. Mean serum Se levels were significantly lower in HPs than in the controls (p?=?0.002); mean levels significantly increased from the first to third blood sampling (p?uric acid levels (inflammation biomarker; p?uric acid levels in these patients could imply an enhanced cardiovascular risk. PMID:21789541

Martí del Moral, Loreto; Agil, Ahmad; Navarro-Alarcón, Miguel; López-Ga de la Serrana, Herminia; Palomares-Bayo, Magdalena; Oliveras-López, María Jesús

2011-12-01

360

Central Obesity, Incident Microalbuminuria, and Change in Creatinine Clearance in the Epidemiology of Diabetes Interventions and Complications Study  

PubMed Central

Weight gain and central obesity are associated with insulin resistance, hypertension, and dyslipidemia in type 1 diabetes. These metabolic abnormalities are risk factors for kidney disease in the general population, but data addressing the relationship of central obesity with kidney disease in type 1 diabetes are limited. Whether waist circumference is associated with incident microalbuminuria and change in creatinine clearance was examined among 1279 participants who had type 1 diabetes and were enrolled in the Epidemiology of Diabetes Interventions and Complications Study, the observational extension of the Diabetes Control and Complications Trial (DCCT). Ninety-three of 1105 participants with normal albumin excretion rate (AER) at DCCT closeout developed incident microalbuminuria over 5.8 yr of follow-up. The hazard ratio for incident microalbuminuria that was associated with each 10-cm greater waist circumference at DCCT closeout was 1.34 (95% confidence interval 1.07 to 1.68), after adjustment for DCCT closeout age, gender, duration of diabetes, treatment group, smoking status, glycosylated hemoglobin, and AER. This increased risk was modestly attenuated when additional adjustment was made for levels of BP and serum lipids. Creatinine clearance declined by an average of 0.34 ml/min per 1.73 m2 each yr over 8 yr of follow-up. Greater rate of decline in creatinine clearance was associated with greater age, conventional insulin therapy during the DCCT, smoking, and greater glycosylated hemoglobin and AER at DCCT closeout but not with waist circumference. In conclusion, waist circumference predicts the subsequent development of microalbuminuria in type 1 diabetes. In contrast, no association of waist circumference with decline in creatinine clearance was observed. PMID:17151331

de Boer, Ian H.; Sibley, Shalamar D.; Kestenbaum, Bryan; Sampson, Joshua N.; Young, Bessie; Cleary, Patricia A.; Steffes, Michael W.; Weiss, Noel S.; Brunzell, John D.

2009-01-01

361

The Association of African Ancestry and Elevated Creatinine in the Coronary Artery Risk Development in Young Adults (CARDIA) Study  

Microsoft Academic Search

Whether genetic factors account for differences in early kidney disease among blacks in a young healthy population is not well known. We evaluated the association of self-reported race and genetic African ancestry with elevated creatinine (?1.3 mg\\/dl for men, ?1.1 mg\\/dl for women) among 3,113 black and white participants in the Coronary Artery Risk Development in Young Adults (CARDIA) study,

Carmen A. Peralta; Neil Risch; Feng Lin; Michael G. Shlipak; Alex Reiner; Elad Ziv; Hua Tang; David Siscovick; Kirsten Bibbins-Domingo

2010-01-01

362

Monitoring of Urea and Potassium by Reverse Iontophoresis In Vitro  

Microsoft Academic Search

Purpose  Reverse iontophoresis is an alternative to blood sampling for the monitoring of endogenous molecules. Here, the potential\\u000a of the technique to measure urea and potassium levels non-invasively, and to track their concentrations during hemodialysis,\\u000a has been examined.\\u000a \\u000a \\u000a \\u000a Materials and Methods  \\u000a In vitro experiments were performed to test (a) a series of subdermal urea and potassium concentrations typical of the pathophysiologic

Valentine Wascotte; M. Begoña Delgado-Charro; Eric Rozet; Pierre Wallemacq; Philippe Hubert; Richard H. Guy; Véronique Préat

2007-01-01

363

Theoretical study on the structures and properties of mixtures of urea and choline chloride.  

PubMed

In this work, we investigated in detail the structural characteristics of mixtures of choline chloride and urea with different urea contents by performing molecular dynamic (MD) simulations, and offer possible explanations for the low melting point of the eutectic mixture of choline chloride and urea with a ratio of 1:2. The insertion of urea molecules was found to change the density distribution of cations and anions around the given cations significantly, disrupting the long-range ordered structure of choline chloride. Moreover, with increasing urea concentration, the hydrogen bond interactions between choline cations and Cl(-) anions decreased, while those among urea molecules obviously increased. From the hydrogen bond lifetimes, it was found that a ratio of 1:2 between choline chloride and urea is necessary for a reasonable strength of hydrogen bond interaction to maintain the low melting point of the mixture of choline chloride with urea. In addition, it was also deduced from the interaction energies that a urea content of 67.7 % may make the interactions of cation-anion, cation-urea and anion-urea modest, and thus results in the lower melting point of the eutectic mixture of choline chloride and urea. The present results may offer assistance to some extent for understanding the physicochemical properties of the eutectic mixture of choline chloride and urea, and give valuable information for the further development and application of deep eutectic solvents. PMID:23435478

Sun, Hui; Li, Yan; Wu, Xue; Li, Guohui

2013-06-01

364

Effects of high ambient temperature on urea-nitrogen recycling in lactating dairy cows.  

PubMed

Effects of exposure to hot environment on urea metabolism were studied in lactating Holstein cows. Four cows were fed ad libitum a total mixed ration and housed in a temperature-controlled chamber at constant moderate (18°C) or high (28°C) ambient temperatures in a cross-over design. Urea nitrogen (N) kinetics was measured by determining urea isotopomer in urine after single injection of [(15) N(2) ]urea into the jugular vein. Both dry matter intake and milk yield were decreased under high ambient temperature. Intakes of total N and digestible N were decreased under high ambient temperature but urinary urea-N excretion was increased. The ratio of urea-N production to digestible N was increased, whereas the proportion of gut urea-N entry to urea-N production tended to be decreased under high ambient temperature. Neither return to the ornithine cycle, anabolic use nor fecal excretion of urea-N recycled to the gut was affected by ambient temperature. Under high ambient temperature, renal clearance of plasma urea was not affected but the gut clearance was decreased. Increase of urea-N production and reduction of gut urea-N entry, in relative terms, were associated with increased urinary urea-N excretion of lactating dairy cows in higher thermal environments. PMID:21794010

Obitsu, Taketo; Kamiya, Mitsuru; Kamiya, Yuko; Tanaka, Masahito; Sugino, Toshihisa; Taniguchi, Kohzo

2011-08-01

365

Antioxidant status of bilirubin and uric acid in patients with myasthenia gravis.  

PubMed

Oxidative stress and changes in antioxidant status have been implicated in the pathogenesis of inflammatory and autoimmune diseases, and free radicals can cause considerable damage to the acetylcholine receptors. 388 individuals, including 97 patients with myasthenia gravis (MG), 135 patients with multiple sclerosis (MS) and 156 healthy controls, were assessed for serum levels of bilirubin and uric acid (UA), in order to determine the levels of these natural antioxidants in the serum. We found that serum UA levels in patients with MG were significantly lower (266.03 ± 93.09 ?mol/l) compared with those of the healthy control group (338.87 ± 107.10 ?mol/l, p = 0.001). However, there was no significant difference of serum UA levels between patients with MG and those with MS (p = 0.071). We also found that serum levels of total, direct and indirect bilirubin in patients with MG were significantly lower, compared with those in the healthy control group, whether male or female. From this study, we conclude that serum levels of bilirubin and UA are lower in MG patients. PMID:22067621

Fuhua, Peng; Xuhui, Deng; Zhiyang, Zhou; Ying, Jiang; Yu, Yang; Feng, Tan; Jia, Liu; Lijia, Gu; Xueqiang, Hu

2012-01-01

366

Does uric acid qualify as an independent risk factor for cardiovascular mortality?  

PubMed

UA (uric acid) is the final product of purine metabolism in humans and is implicated in many disease conditions. Sustained hyperuricaemia has putative adverse roles in cardiovascular diseases. Despite strong evidence emerging from large epidemiological studies supporting the hypothesis that UA independently influences cardiovascular disease outcomes and mortality, a causal role is yet to be established. Serum UA is also considered as a useful biomarker for mortality in high-risk patients with acute coronary syndromes, heart failure and hypertension and in patients with Type 2 diabetes mellitus. Post-hoc analyses of clinical trial data suggest beneficial effects of reducing serum UA. However, these findings are inconclusive and are only hypothesis-generating. In the present issue of Clinical Science, Ndrepepa and co-workers have investigated the prognostic role of UA in high-risk Type 2 diabetic patients with established coronary artery disease in predicting 1-year survival and cardiovascular mortality. These results support the independent role of serum UA in predicting survival in Type 2 diabetic patients. However, long-term follow-up studies are required with serial UA measurement to establish the time-dependent association of UA with mortality outcomes. PMID:23043434

Jeemon, Panniyammakal; Prabhakaran, Dorairaj

2013-02-01

367

Blood groups, serum cholesterol, serum uric acid, blood pressure, and obesity in adolescents.  

PubMed Central

To assess the association of blood groups with coronary risk factors, data were examined from the third cycle of the National Health Examination Survey. In a nationwide sample of more than 6000 black and white adolescents aged 12 to 17 years, ABO blood group, haptoglobin phenotype, selected other genetic markers of blood and secretions, and coronary risk factor levels were measured. Blood group A1 was associated with significantly higher serum total cholesterol levels in white females independent of multiple potential confounders, in white males independent of age and weight, and in southern black females independent of age and weight. ABO blood group was not significantly associated with blood pressure, resting heart rate, or subscapular skinfold thickness. An association with serum uric acid in white males was not independent of weight. In white males only, haptoglobin phenotype 2-2 was associated with significantly higher serum cholesterol levels than 1-1 or 2-1 adjusting for age and weight. No consistent associations were found between Rh types, ABH secretor ability, or group-specific component types and risk factors. This analysis of national data confirms previously reported associations of blood group A with higher serum total cholesterol levels in white adults and adolescents. PMID:1956079

Gillum, R. F.

1991-01-01

368

The relationship between serum uric acid levels and ?-cell functions in nondiabetic subjects.  

PubMed

High serum uric acid (UA) levels are believed to be an independent risk factor for the development of diabetes. We aimed to investigate the relationship between serum UA concentrations and early-phase insulin secretion following a 75 g oral glucose tolerance test (OGTT) in nondiabetic subjects. We enrolled 570 Japanese subjects (354 males and 216 females, aged 50.5 ± 8.9 years and 52.6 ± 7.3 years, respectively), who underwent the 75 g OGTT during their annual health examination. The OGTT confirmed their nondiabetic status. Insulin secretion was estimated by the disposition index (DI) [(? insulin/? glucose (0-30 min) × (1/HOMA-IR)], which is an adjusted measure of ?-cell function relative to variations in insulin sensitivity. Simple linear regression analysis showed negative correlations between serum UA levels and DI, when examined in the whole study population and female subjects only (r = -0.209, p < 0.001 and r = -0.232, p < 0.001, respectively). However, in male subjects, UA levels did not correlate with DI. In females, multivariate linear regression analysis revealed that serum UA levels were the major predictors of DI, explaining 16.4% of its variation (p < 0.001). Serum UA levels significantly correlate with early-phase insulin secretion in nondiabetic Japanese women. It may be an independent risk factor for predicting ?-cell function in women. PMID:25295417

Shimodaira, M; Niwa, T; Nakajima, K; Kobayashi, M; Hanyu, N; Nakayama, T

2014-12-01

369

The Association between Serum Uric Acid and Residual ?-Cell Function in Type 2 Diabetes  

PubMed Central

The aim of this study was to investigate the relationship of serum uric acid (sUA) with residual ?-cell function in type 2 diabetes. Oral glucose tolerance tests (OGTT) were performed on 1021 type 2 diabetes patients. The ratio of area under curve of insulin to glucose during 0 to 30?min and 0 to 120?min of the OGTT was calculated as indices of insulin secretion function. The products of insulin secretion indices multiplied by Matsuda insulin sensitivity index were used as disposition indices. After correlation and multiple linear regression analysis, sUA was significantly associated with insulin secretion and disposition indices in male, female, and total groups adjusted for confounding factors (including metabolic indicators like sex, age, course of the disease, blood glucose, blood pressure, serum lipids, and so on). Superficially steeper time-dependent decline of insulin secretion function was found in patients with sUA above the median than those below it. In conclusion, our results suggest an independent positive association between sUA and residual ?-cell function in type 2 diabetes. Patients with higher sUA have greater insulin secretion ability than those with lower sUA at the early stage of disease, but their residual ?-cell function seems to decay more rapidly. PMID:24971368

Tang, Wei; Fu, Qi; Zhang, Qingqing; Sun, Min; Gao, Yuan; Liu, Xuan; Qian, Li; Shan, Shan; Yang, Tao

2014-01-01

370

Serum Uric Acid and Nigral Iron Deposition in Parkinson’s Disease: A Pilot Study  

PubMed Central

Background Uric acid (UA) is an endogenous antioxidant which is known to reduce oxidative stress and also chelate iron ion. Recent studies have provided evidence that UA may play a neuroprotective role in Parkinson’s disease (PD). However, it is unknown whether UA relates to nigral iron deposition, which is a characteristic pathophysiological alteration in PD. The aim of this study was to determine the potential relationship of these two markers in patients with PD. Methods A total of 30 patients of PD and 25 age- and gender- matched healthy controls underwent 3-Tesla MRI and laboratory tests including serum UA levels. We assessed iron levels by measuring phase shift values using susceptibility-weighted image. Mean phase shift values of the substantia nigra (SN), red nucleus, head of the caudate nucleus, globus pallidus, putamen, thalamus, and frontal white matter were calculated and correlated with serum UA levels. Results Serum UA levels were significantly decreased in the PD patients than in the controls. Phase shift values in bilateral SN were significantly increased in the PD patients than in the controls. There was no significant correlation between serum UA levels and nigral phase shift values. Conclusions As previous studies, low serum UA level and increased nigral iron content in the PD was reconfirmed in this study. However, we failed to find the relationship between these two markers. Our data suggest that serum UA may not be important determinant of nigral iron deposition in PD. PMID:25386854

Kim, Tae-Hyoung; Lee, Jae-Hyeok

2014-01-01

371

pH-Dependent urea-induced unfolding of stem bromelain: unusual stability against urea at neutral pH.  

PubMed

Equilibrium unfolding of stem bromelain (SB) with urea as a denaturant has been monitored as a function of pH using circular dichroism and fluorescence emission spectroscopy. Urea-induced denaturation studies at pH 4.5 showed that SB unfolds through a two-state mechanism and yields DeltaG (free energy difference between the fully folded and unfolded forms) of approximately 5.0 kcal/mol and C(m) (midpoint of the unfolding transition) of approximately 6.5 M at 25 degrees C. Very high concentration of urea (9.5 M) provides unusual stability to the protein with no more structural loss and transition to a completely unfolded state. PMID:19961414

Ahmad, B; Rathar, G M; Varshney, A; Khan, R H

2009-12-01

372

40 CFR 721.9900 - Urea, condensate with poly[oxy(methyl-1,2-ethanediyl)]-?- (2-aminomethylethyl)-?-(2-amino...  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Urea, condensate with poly[oxy(methyl-1...Specific Chemical Substances § 721.9900 Urea, condensate with poly[oxy(methyl-1...reporting. (1) The chemical substance urea, condensate with...

2010-07-01

373

40 CFR 721.9900 - Urea, condensate with poly[oxy(methyl-1,2-ethanediyl)]-?- (2-aminomethylethyl)-?-(2-amino...  

Code of Federal Regulations, 2011 CFR

...2011-07-01 2011-07-01 false Urea, condensate with poly[oxy(methyl-1...Specific Chemical Substances § 721.9900 Urea, condensate with poly[oxy(methyl-1...reporting. (1) The chemical substance urea, condensate with...

2011-07-01

374

Common Variants Related to Serum Uric Acid Concentrations Are Associated with Glucose Metabolism and Insulin Secretion in a Chinese Population  

PubMed Central

Background Elevated serum uric acid concentration is an independent risk factor and predictor of type 2 diabetes (T2D). Whether the uric acid-associated genes have an impact on T2D remains unclear. We aimed to investigate the effects of the uric acid-associated genes on the risk of T2D as well as glucose metabolism and insulin secretion. Method We recruited 2,199 normal glucose tolerance subjects from the Shanghai Diabetes Study I and II and 2,999 T2D patients from the inpatient database of Shanghai Diabetes Institute. Fifteen single nucleotide polymorphisms (SNPs) mapped in or near 11 loci (PDZK1, GCKR, LRP2, SLC2A9, ABCG2, LRRC16A, SLC17A1, SLC17A3, SLC22A11, SLC22A12 and SF1) were genotyped and serum biochemical parameters related to uric acid and T2D were determined. Results SF1 rs606458 showed strong association to T2D in both males and females (p = 0.034 and 0.0008). In the males, LRRC16A was associated with 2-h insulin and insulin secretion (p = 0.009 and 0.009). SLC22A11 was correlated with HOMA-B and insulin secretion (p = 0.048 and 0.029). SLC2A9 rs3775948 was associated with 2-h glucose (p = 0.043). In the females, LRP2 rs2544390 and rs1333049 showed correlations with fasting insulin, HOMA-IR and insulin secretion (p = 0.028, 0.033 and 0.052 and p = 0.034, 0.047 and 0.038, respectively). SLC2A9 rs11722228 was correlated with 2-h glucose, 2-h insulin and insulin secretion (p = 0.024, 0.049 and 0.049, respectively). Conclusions Our results indicated that the uric acid-associated genes have an impact on the risk of T2D, glucose metabolism and insulin secretion in a Chinese population. PMID:25617895

Sun, Xue; Zhang, Rong; Jiang, Feng; Tang, Shanshan; Chen, Miao; Peng, Danfeng; Yan, Jing; Wang, Tao; Wang, Shiyun; Bao, Yuqian; Hu, Cheng; Jia, Weiping

2015-01-01

375

Creatinine and specific gravity normalization in biological monitoring of occupational exposures.  

PubMed

Reference values for the biological monitoring of occupational exposures are generally normalized on the basis of creatinine (CR) concentration or specific gravity (SG) to account for fluctuations in urine dilution. For instance, the American Conference of Governmental Industrial Hygienists (ACGIH®) uses a reference value of 1g/L for CR. The comparison of urinary concentrations of biomarkers between studies requires the adjustment of results based on a reference CR and/or SG value, although studies have suggested that age, sex, muscle mass, and time of the day can exert non-negligible influences on CR excretion, while SG appears to be less affected. The objective of this study was to propose reference values for urinary CR and SG based on the results of samples sent for analysis by occupational health practitioners to the laboratory of the Occupational Health and Safety Research Institute of Québec (IRSST). We analyzed a database containing 20,395 urinary sample results collected between 1985 and 2010. Linear mixed-effects models with worker as a random effect were used to estimate the influence of sex and collection period on urinary CR and SG. Median CR concentrations were 25-30% higher in men (1.6 g/L or 14.4 mmol/L) than in women (1.2 g/L or 10.2 mmol/L). Four percent of the samples for men and 12% for women were below the acceptable threshold for CR (4.4 mmol/L). For SG, 5% of samples for men and 12% for women were below the threshold of 1.010. The difference in SG levels between sexes was lower than for CR, with a median of 1.024 for men compared to 1.020 for women. Our results suggest that the normalization of reference values based on a standard CR value of 1 g/L as proposed by the ACGIH is a conservative approach. According to the literature, CR excretion is more influenced by physiological parameters than SG. We therefore suggest that correction based on SG should be favored in future studies involving the proposal of reference values for the biological monitoring of occupational exposures. PMID:25192246

Sauvé, Jean-François; Lévesque, Martine; Huard, Mélanie; Drolet, Daniel; Lavoué, Jérôme; Tardif, Robert; Truchon, Ginette

2015-02-01

376

The expression of aflatoxicosis in broiler chicks with respect to supplemental dietary lysine and methionine levels  

E-print Network

phosphorous, total protein, triglycerides, uric acid, and increased blood urea nitrogen but did not affect creatinine levels. Response surface regression suggests that in the presence of aflatoxin, maximum body weight and feed efficiency could be obtained... that poultry recover readily even though rate and level of recovery may be dose related. Changes in clinical chemistry blood values have been noted by many to be associated with liver function (Norred, 1986; Richard et al. , 1975; Thurston et al. , 1980...

Mills, John Salazar

2012-06-07

377

Effect of fenugreek ( Trigonella foenum-graecum L) seeds on serum parameters in normal and streptozotocin-induced diabetic rats  

Microsoft Academic Search

Many herbal medicines have been recommended for the treatment of diabetes. The antidiabetic effect of fenugreek ethanolic extract (Trigonella-foenum graecum L) was investigated in normal and streptozotocin-induced diabetic rats. Oral administration of fenugreek extract (0.1, 0.25, and 0.5 g\\/kg body weight) for 14 days on the level of serum glucose, total cholesterol, triacylglycerol, urea, uric acid, creatinine, aspartate aminotransferase (AST)

Akram Eidi; Maryam Eidi; Mousa Sokhteh

2007-01-01

378

Oligomeric Structure and Functional Characterization of the Urea Transporter from Actinobacillus pleuropneunomiae  

PubMed Central

Urea transporters facilitate urea permeation across cell membranes in prokaryotes and eukaryotes. Bacteria use urea either as a means to survive in acidic environments and/or as a nitrogen source. The urea transporter ApUT from Actinobacillus pleuropneumoniae, the pathogen that causes porcine pleurisy and pneumonia, was expressed in E. coli and purified. Analysis of the recombinant protein using cross-linking and blue-native gel electrophoresis established that ApUT is a dimer in detergent solution. To determine the urea transport kinetics of ApUT, purified protein was reconstituted into proteoliposomes, and urea efflux was measured by stopped-flow fluorometry. The measured urea flux was saturable, could be inhibited by phloretin, and was not affected by pH. Two-dimensional crystals of the biologically active ApUT show that it is also dimeric in a lipid membrane and provide the first structural information on a member of the urea transporter family. PMID:19361419

Raunser, Stefan; Mathai, John C.; Abeyrathne, Priyanka D.; Rice, Amanda J.; Zeidel, Mark L.; Walz, Thomas

2009-01-01

379

40 CFR 721.6440 - Polyamine urea-for-malde-hyde condensate (specific name).  

Code of Federal Regulations, 2010 CFR

...Environment 30 2010-07-01 2010-07-01 false Polyamine urea-for-malde-hyde condensate (specific name). 721.6440...Uses for Specific Chemical Substances § 721.6440 Polyamine urea-for-malde-hyde condensate (specific name)....

2010-07-01

380

Urea destabilizes RNA by forming stacking interactions and multiple hydrogen bonds with nucleic acid bases  

E-print Network

Urea titration of RNA by urea is an effective approach to investigate the forces stabilizing this biologically important molecule. We used all atom molecular dynamics simulations using two urea force fields and two RNA constructs to elucidate in atomic detail the destabilization mechanism of folded RNA in aqueous urea solutions. Urea denatures RNA by forming multiple hydrogen bonds with the RNA bases and has little influence on the phosphodiester backbone. Most significantly we discovered that urea engages in stacking interactions with the bases. We also estimate, for the first time, m-value for RNA, which is a measure of the strength of urea-RNA interactions. Our work provides a conceptual understanding of the mechanism by which urea enhances RNA folding rates.

Priyakumar, U Deva; Thirumalai, D; MacKerell, Alexander D

2009-01-01

381

Urea destabilizes RNA by forming stacking interactions and multiple hydrogen bonds with nucleic acid bases  

E-print Network

Urea titration of RNA by urea is an effective approach to investigate the forces stabilizing this biologically important molecule. We used all atom molecular dynamics simulations using two urea force fields and two RNA constructs to elucidate in atomic detail the destabilization mechanism of folded RNA in aqueous urea solutions. Urea denatures RNA by forming multiple hydrogen bonds with the RNA bases and has little influence on the phosphodiester backbone. Most significantly we discovered that urea engages in stacking interactions with the bases. We also estimate, for the first time, m-value for RNA, which is a measure of the strength of urea-RNA interactions. Our work provides a conceptual understanding of the mechanism by which urea enhances RNA folding rates.

U. Deva Priyakumar; Changbong Hyeon; D. Thirumalai; Alexander D. MacKerell Jr

2009-12-07

382

40 CFR 721.6440 - Polyamine urea-for-malde-hyde condensate (specific name).  

Code of Federal Regulations, 2011 CFR

...Environment 31 2011-07-01 2011-07-01 false Polyamine urea-for-malde-hyde condensate (specific name). 721.6440...Uses for Specific Chemical Substances § 721.6440 Polyamine urea-for-malde-hyde condensate (specific name)....

2011-07-01

383

40 CFR 418.30 - Applicability; description of the urea subcategory.  

Code of Federal Regulations, 2013 CFR

...418.30 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS FERTILIZER MANUFACTURING POINT SOURCE CATEGORY Urea Subcategory § 418.30 Applicability; description of the urea...

2013-07-01

384

40 CFR 418.30 - Applicability; description of the urea subcategory.  

Code of Federal Regulations, 2010 CFR

...418.30 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS FERTILIZER MANUFACTURING POINT SOURCE CATEGORY Urea Subcategory § 418.30 Applicability; description of the urea...

2010-07-01

385

The uric acid transporter SLC2A9 is a direct target gene of the tumor suppressor p53 contributing to antioxidant defense.  

PubMed

Only humans and higher primates have high uric acid blood levels. Although high uric acid causes gout, it has been linked with human longevity because of its hypothetical antioxidant function. Recent studies reveal that p53 has significant roles in cellular metabolism. One example of this is an antioxidant function that potentially contributes to tumor suppression. Here, we reported a first beneficial link between p53 and uric acid. We identified the uric acid transporter SLC2A9 (also known as GLUT9) as a direct p53 target gene and a key downstream effector in the reduction of reactive oxygen species (ROS) through transporting uric acid as a source of antioxidant. Oxidative stress induced SLC2A9 expression in a p53-dependent manner, and inhibition of SLC2A9 by small interfering RNA (siRNA) or anti-gout drugs such as probenecid significantly increased ROS levels in an uric acid-dependent manner and greatly sensitized cancer cells to chemotherapeutic drugs. Conversely, expression of SLC2A9 reduced ROS and protected against DNA damage and cell death, suggesting its antioxidant function. The increased production of ROS because of p53 loss was rescued by SLC2A9 expression. Furthermore, decreased SLC2A9 expression was observed in several cancer types and was associated with a poorer prognosis. Our findings suggest that the p53-SLC2A9 pathway is a novel antioxidant mechanism that uses uric acid to maintain ROS homeostasis and prevent accumulation of ROS-associated damage that potentially contributes to cancer development.Oncogene advance online publication, 26 May 2014; doi:10.1038/onc.2014.119. PMID:24858040

Itahana, Y; Han, R; Barbier, S; Lei, Z; Rozen, S; Itahana, K

2014-05-26

386

Performance of cellulose acetate butyrate membranes in hyperfiltration of sodium chloride and urea feed solution  

NASA Technical Reports Server (NTRS)

Cellulose acetate butyrate (CAB) membranes are shown to give high salt and urea rejection with water flux of about 3 gallons/sq ft per day at 600 psig. Membranes prepared from a formulation containing glyoxal show a significant increase in flux and decrease in salt and urea rejection with drying time. Zero drying time gives maximum urea and salt rejection and is therefore most suitable for hyperfiltration of sodium chloride and urea feed solution.

Wydeven, T.; Leban, M.

1973-01-01

387

Piezoelectric urea biosensor based on immobilization of urease onto nanoporous alumina membranes  

Microsoft Academic Search

The urease was immobilized onto nanoporous alumina membranes prepared by the two-step anodization method, and a novel piezoelectric urea sensing system with separated porous alumina\\/urease electrode has been developed through measuring the conductivity change of immobilized urease\\/urea reaction. The process of urease immobilization was optimized and the performance of the developed urea biosensor was evaluated. The obtained urea biosensor presented

Zhengpeng Yang; Shihui Si; Hongjuan Dai; Chunjing Zhang

2007-01-01

388

Reduction in slow intercompartmental clearance of urea during dialysis  

SciTech Connect

The kinetics of urea and inulin were analyzed in five anesthetized dogs during sequential 2-hour periods before, during, and after hemodialysis. The distribution of both compounds after simultaneous intravenous injection was characterized by three-compartment models, and the total volumes of urea (0.66 +/- 0.05 L/kg) and inulin (0.19 +/- 0.01 L/kg) distribution were similar to expected values for total body water and extravascular space, respectively. Intercompartmental clearances calculated before dialysis were used to estimate blood flows to the fast and slow equilibrating compartments. In agreement with previous results, the sum of these flows was similar to cardiac output, averaging 101% of cardiac output measured before dialysis (range 72% to 135%). Dialysis was accompanied by reductions in the slow intercompartmental clearances of urea (81%) and inulin (47%), which reflected a 90% attenuation in blood flow supplying the slow equilibrating compartments. This was estimated to result in a 10% average reduction in the efficiency with which urea was removed by dialysis (range 2.0% to 16.4%). Mean arterial pressure fell by less than 5% during dialysis, but total peripheral resistance increased by 47% and cardiac output fell by 35%. In the postdialysis period, total peripheral resistance and cardiac output returned toward predialysis values, but blood flow to the slow equilibrating peripheral compartment was still reduced by 80%. These changes parallel activation of the renin-angiotensin system, but further studies are required to establish causality.

Bowsher, D.J.; Krejcie, T.C.; Avram, M.J.; Chow, M.J.; Del Greco, F.; Atkinson, A.J. Jr.

1985-04-01

389

Tailoring of analytical performances of urea biosensors using nanomaterials  

NASA Astrophysics Data System (ADS)

This paper is a contribution to the study of enzymatic sensors based on nanoparticles of iron oxide (FeNPs). Urease enzyme was immobilized on FeNPs using layer-by-layer (LbL) deposition method. FeNPs were first coated with polyelectrolytes (PE): Poly (allylamine hydrochloride), PAH and Poly (sodium 4-styrenesulfonate), PSS for enzyme immobilization and then with enzyme. It has been confirmed through zeta potential measurements of FeNPs that the enzyme is immobilized on the surface. We evaluated the sensitivity of biosensors for urea by potentiometric and capacitive measurements on silicon / silica / FeNP-LBL-urease structures. The recorded capacity-potential curves (C-V) show a significant shift of flat band potential towards negative potentials in the presence of urea, the observed values of sensitivity vary between 30 and 40 mV/p[urea]. It has been shown that the proposed method for the immobilization of urease can increase the dynamic range of urea detection (10-4M to 10-1M) compared to the immobilization of urease without FeNP (10-3.5 M to 10-2.5 M). When the number of PAH-PSS layers was increased the sensitivity of detection was modified. This effect is due to partial inhibition of the enzyme in presence of FeNPs, which was shown by measurements in homogeneous phase.

Nouira, W.; Barhoumi, H.; Maaref, A.; Jaffrézic Renault, N.; Siadat, M.

2013-03-01

390

IRIS Toxicological Review of Urea (Interagency Science Consultation Draft)  

EPA Science Inventory

On September 28, 2010, the Toxicological Review of Urea and the charge to external peer reviewers were released for external peer review and public comment. The Toxicological Review and charge were reviewed internally by EPA and by other federal agencies and White House Of...

391

Some studies on starch–urea–acid reaction mechanism  

Microsoft Academic Search

Starch reacted with urea in the absence or presence of mineral acids or mineral acid salts at 150°C for various reaction durations. The acids used were phosphoric, nitric, and sulphuric and the salts used were ammonium sulphate, ammonium nitrate, ammonium chloride and magnesium sulphate. The reaction extent was followed by monitoring nitrogen content. Carrying out the reaction of starch and

M. I Khalil; S Farag; A. A Aly; A Hebeish

2002-01-01

392

Pt nanoflower/polyaniline composite nanofibers based urea biosensor.  

PubMed

Hybrid materials with special structures are of great interest because of their superior properties compared with their pure counterparts. Hybrid polyaniline (PANi) nanofibers with integrated Pt nanoflowers are studied in this research. PANi is prepared by in situ polymerization of aniline on an electrospun nanofiber template in an acidic solution with ammonium persulfate (APS) as the oxidant. Pt nanoflowers are further electrodeposited onto the PANi nanofibers backbone by cyclic voltammetry (CV), resulting in novel functionalized hybrid nanofibers. The coverage of Pt nanoflowers on PANi nanofibers can be facilely controlled by adjusting the electrodeposition conditions. The factors affecting Pt nanoflowers formation are further investigated. As a demonstration, urease is immobilized onto the Pt/PANi hybrid nanofibers and the composite was employed as the sensing platform for urea detection in a flow-injection-analysis (FIA) system. The detection of urea shows a wide linear range (up to 20 mM), a good limit of detection of 10 ?M (S/N=3), and an excellent anti-interference property against chloride ion. In addition, it was found that the response to urea was attributed not only to the conductivity change of PANi due to the interaction between PANi and ammonia (liberated from the enzymatic reaction), but also to the interaction between Pt nanoflowers and amine groups in urea. The strategy developed in this study can be extended to synthesize other composite nanofibers consisting of conducting polymer and metal nanoparticles for a wide range of sensing applications. PMID:21986562

Jia, Wenzhao; Su, Liang; Lei, Yu

2011-12-15

393

Using urea to decompose polylactic acid in bark compost  

Microsoft Academic Search

Polylactic acid (PLA) is a plastic of plant origin. Because it is biodegradable, it is used for various environmentally friendly materials, such as sand bags and mulching sheets for agriculture and construction. However, PLA biodegrades very slowly and only a few microorganisms can biodegrade it. We tested a biodegrading method that uses urea to accelerate the decomposition of PLA cloth

Kenji Nakamura

394

New urea-absorbing polymers for artificial kidney machines  

NASA Technical Reports Server (NTRS)

Etherified polymer is made from modified cellulose derivative which is reacted with periodate. It will absorb 2 grams of urea per 100 grams of polymer. Indications are that polymers could be used to help remove uremic wastes in artificial kidneys, or they could be administered orally as therapy for uremia.

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

1975-01-01

395

Crystal growth and nonlinear optical studies of m-dinitrobenzene doped urea  

Microsoft Academic Search

Urea is an attractive material for frequency conversion of high power lasers to UV but the frequent use of urea (U) crystal at normal atmosphere is troublesome due to its hygroscopic nature. The hygroscopic character of urea has been modified by making the solid solution with m-dinitrobenzene (DNB). The phase diagram of DNB and U shows the formation of a

R. N. Rai; S. R. Mudunuri; R. S. B. Reddi; V. S. A. Kumar Satuluri; S. Ganeshmoorthy; P. K. Gupta

2011-01-01

396

Urea-Induced Denaturation of PreQ1Riboswitch Jeseong Yoon,  

E-print Network

components of nucleotides makes urea a powerful chemical denaturant for nucleic acids. INTRODUCTION Neutral with the bases. Through detailed studies of the simulation trajectories, we found that geminate pairs between urea and bases due to hydrogen bonds and stacks persist only 0.1-1 ns, which suggests that the urea-base

Thirumalai, Devarajan

397

Judith Beekman and Ronald L. Thune Evaluation of the Role of Ammonia and Urea  

E-print Network

1 Judith Beekman and Ronald L. Thune Evaluation of the Role of Ammonia and Urea Transporters and ammonia transporters in a urease gene cluster · Hypothesis: The E. ictaluri urea and ammonia transporters are actively expressed ­Aim 1. Demonstrate transcription of the E. ictaluri urea and ammonia transporters ­Aim

Kane, Andrew S.

398

Urea cycling and ammonia absorption in vivo in the digestive tract of the rat  

E-print Network

Urea cycling and ammonia absorption in vivo in the digestive tract of the rat C. DEMIGNÃ? C. RÃ?MÃ?SY. The transfer of blood urea into the digestive tract and ammonia absorption at that site have been studied in vivo in anesthetized rats. The vein-artery differences in urea and ammonia absorption were greater

Paris-Sud XI, Université de

399

ORIGINAL PAPER Urea-induced hypometabolism in the hibernating wood frog  

E-print Network

ORIGINAL PAPER Urea-induced hypometabolism in the hibernating wood frog (Rana sylvatica-induced hypometabolism observed in hibernating R. sylvatica results from inhibition of energy-utilizing processes urea depresses metabolic rate. Keywords Mitochondria Á Metabolism Á Urea Á Hibernation Á Rana sylvatica

Lee Jr., Richard E.

400

Growth and properties of urea-doped triglycine sulfate (UrTGS) crytals  

Microsoft Academic Search

This paper discusses the growth and properties of triglycine sulfate (TGS) crystals doped with urea. It was found that the normalized growth yield and pyroelectric and dielectric constants could be increased significantly by urea additions. TGS crystals doped with 5 and 10 wt% urea exhibited up to five times higher material figures of merit for infrared pyroelectric detectors compared with

Jiann-Min Chang; A. K. Batra; R. B. Lal

1996-01-01

401

75 FR 78243 - Propionic Acid and Salts, Urea Sulfate, Methidathion, and Methyl Parathion; Registration Review...  

Federal Register 2010, 2011, 2012, 2013, 2014

...EPA-HQ-OPP-2010-0650; FRL-8855-5] Propionic Acid and Salts, Urea Sulfate, Methidathion, and Methyl...decisions for the pesticides propionic acid and salts, case no. 4078, urea sulfate, case...the table below--propionic acid and salts, case 4078, urea sulfate, case...

2010-12-15

402

Effect of the Protein Denaturants Urea and Guanidinium on Water Structure: A Structural and Thermodynamic Study  

E-print Network

Effect of the Protein Denaturants Urea and Guanidinium on Water Structure: A StructuralVania 19104-6059 ReceiVed May 4, 1998 Abstract: The mechanism of the denaturing effects of urea of denaturation is discussed. Introduction The mechanism by which urea and the guanidinium ion denature proteins

Sharp, Kim

403

Urea denaturation by stronger dispersion interactions with proteins than water implies a 2-stage unfolding  

E-print Network

Urea denaturation by stronger dispersion interactions with proteins than water implies a 2-stage of denaturation of proteins by urea is explored by using all-atom microseconds molecular dynamics simulations mechanism'' whereby urea has a stronger dispersion interaction with protein than water. denaturing mechanism

Thirumalai, Devarajan

404

Detailed modeling of the evaporation and thermal decomposition of urea-water-solution in SCR systems  

E-print Network

Detailed modeling of the evaporation and thermal decomposition of urea-water-solution in SCRE Journal. Keywords: Multi-component, , evaporation, UWS, Adbue, urea decomposition, thermolysis SCR, kinetics Abstract This work aims to develop a multi-component evaporation model for droplets of urea

Boyer, Edmond

405

PHYSIOLOGY AND YIELD RESPONSES OF COTTON TO FOLIAR UREA WITH NBPT  

Technology Transfer Automated Retrieval System (TEKTRAN)

Urea is the most recommended foliar N source, due to its relatively low toxicity, quick absorption, and low cost. However, in the literature reports of yield increments with foliar urea application are not consistent. The objectives of this research were to study foliar urea assimilation in cotton...

406

CONTRAST ENHANCED SPIRAL COMPUTERIZED TOMOGRAPHY IN PATIENTS WITH CHRONIC OBSTRUCTIVE UROPATHY AND NORMAL SERUM CREATININE: A SINGLE SESSION FOR ANATOMICAL AND FUNCTIONAL ASSESSMENT  

Microsoft Academic Search

Purpose:We evaluated contrast enhanced spiral computerized tomography (CT) as a single session for the anatomical and functional assessment of patients with chronic obstructive uropathy and normal serum creatinine.

MOHAMED E. ABO EL-GHAR; AHMED A. SHOKEIR; TAREK A. EL-DIASTY; HODA F. REFAIE; HOSSAM M. GAD; AHMED B. SHEHAB EL-DEIN

2004-01-01

407

Simultaneous electrochemical detection of dopamine and uric acid over ceria supported three dimensional gold nanoclusters  

NASA Astrophysics Data System (ADS)

CeO2 is well known for being an active material to support the growth of Au nanoclusters (Au NCs). In this work, three dimensional (3D) Au NCs were deposited on three different shaped CeO2 nanostructures such as nanoparticles (NPs), nanorod arrays (NRAs) and nanoflowers (NFs) modified Ti substrate for electrochemical simultaneous detection of dopamine (DA) and uric acid (UA). The electrodeposition of 3D Au NCs were carried out via cyclic voltammetric (CV) method at over-potential, while CeO2 nanostructures were deposited by galvanostatic constant current method under the optimized conditions. The morphology and elemental composition analysis of 3D Au NCs with CeO2 nanostructures were characterized by SEM, XRD, XPS and EDAX measurements. The electrocatalytic activity of 3D Au NCs on different CeO2 supports were thoroughly investigated by using voltammetric and amperometric techniques. According to the obtained results, CeO2 NPs supported 3D Au NCs (3D Au NCs@CeO2 NPs) displayed strong signal for DA as compared to that of CeO2 NRAs (3D Au NCs@CeO2 NRAs) and CeO2 NFs supported 3D Au NCs (3D Au NCs@CeO2 NFs). In addition, the 3D Au NCs@CeO2 NPs electrode resulted in more sensitive and simultaneous detection of DA in the presence of excess UA. Thus, the 3D Au NCs@CeO2 NPs electrode can practically be applied for the detection of DA using biological samples.

Palanisamy, Sivakumar

2014-12-01

408

Serum Uric Acid Predicts Declining of Circulating Proangiogenic Mononuclear Progenitor Cells in Chronic Heart Failure Patients  

PubMed Central

Introduction: Serum uric acid (SUA) is considered a marker for natural progression of chronic heart failure (CHF) mediated cardiovascular remodelling. CHF associates with declining of circulating mononuclear progenitor cells (MPCs). The objective of this study was to evaluate the interrelationship between SUA concentrations and proangiogenic MPCs in ischemic CHF patients. Methods: The study population was structured retrospectively after determining the coronary artery disease (CAD) by contrast-enhanced spiral computed tomography angiography in 126 subjects with symptomatic ischemic mild-to-severe CHF and 128 CAD subjects without CHF. Baseline biomarkers were measured in all patients. Cox proportional multivariate hazard ratio was calculated for predictors of MPCs declining in both CHF and non-CHF patient population predictors of MPCs declining in CHF subjects were examined in stepwise logistic regression. C-statistics, integrated discrimination indices (IDI) and net-reclassification improvement were utilized for prediction performance analyses. Results: Cox proportional adjusted hazard ratio analyses for CD14+CD309+ and CD14+CD309+Tie2+ MPCs by SUA has shown that the higher quartiles (Q3 and Q4) of SUA compared to the lower quartiles (Q1 and Q2) are associated with increased risks of depletion of both CD14+CD309+ and CD14+CD309+Tie2+ MPCs. The addition of Q4 SUA to the ABC model improved the relative IDI by 13.8% for depletion of CD14+CD309+ MPCs and by 14.5% for depletion of CD14+CD309+Tie2+ MPCs. Conclusion: Circulating levels of proangiogenic MPCs are declined progressively depending on the levels of SUA in the HF subjects with CHF. We suggest that even mild elevations of SUA might be used to predict of relative depletion of proangiogenic MPCs among chronic HF patients. PMID:25320662

Berezin, Alexander E.; Kremzer, Alexander A.; Samura, Tatyana A.; Berezina, Tatyana A.; Martovitskaya, Yulia V.

2014-01-01

409

On the mechanism of d-amphetamine-induced changes in glutamate, ascorbic acid and uric acid release in the striatum of freely moving rats  

PubMed Central

The effects of systemic, intrastriatal or intranigral administration of d-amphetamine on glutamate, aspartate, ascorbic acid (AA), uric acid, dopamine (DA), dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA) concentrations in dialysates from the striatum of freely-moving rats were evaluated using microdialysis. d-Amphetamine (2?mg?kg?1) given subcutaneously (s.c.) increased DA, AA and uric acid and decreased DOPAC+HVA, glutamate and aspartate dialysate concentrations over a 3?h period after d-amphetamine. 5-HIAA concentrations were unaffected. Individual changes in glutamate and AA dialysate concentrations were negatively correlated. d-Amphetamine (0.2?mM), given intrastriatally, increased DA and decreased DOPAC+HVA and aspartate dialysate concentrations, but failed to change those of glutamate, AA uric acid or 5-HIAA, over a 2?h period after d-amphetamine. Haloperidol (0.1?mM), given intrastriatally, increased aspartate concentrations without affecting those of glutamate or AA. d-Amphetamine (0.2?mM), given intranigrally, increased AA and uric acid dialysate concentrations and decreased those of glutamate, aspartate and DA; DOPAC+HVA and 5-HIAA concentrations were unaffected. These results suggest that d-amphetamine-induced increases in AA and uric acid and decreases in glutamate concentrations are triggered at nigral sites. The changes in aspartate levels may be evoked by at least two mechanisms: striatal (mediated by inhibitory dopaminergic receptors) and nigral (activation of amino acid carrier-mediated uptake). PMID:10711358

Miele, Maddalena; Mura, Maria A; Enrico, Paolo; Esposito, Giovanni; Serra, Pier A; Migheli, Rossana; Zangani, Danilo; Miele, Egidio; Desole, Maria S

2000-01-01

410

Comparison of time-dependent effects of (+)-methamphetamine or forced swim on monoamines, corticosterone, glucose, creatine, and creatinine in rats  

PubMed Central

Background Methamphetamine (MA) use is a worldwide problem. Abusers can have cognitive deficits, monoamine reductions, and altered magnetic resonance spectroscopy findings. Animal models have been used to investigate some of these effects, however many of these experiments have not examined the impact of MA on the stress response. For example, numerous studies have demonstrated (+)-MA-induced neurotoxicity and monoamine reductions, however the effects of MA on other markers that may play a role in neurotoxicity or cell energetics such as glucose, corticosterone, and/or creatine have received less attention. In this experiment, the effects of a neurotoxic regimen of (+)-MA (4 doses at 2 h intervals) on brain monoamines, neostriatal GFAP, plasma corticosterone, creatinine, and glucose, and brain and muscle creatine were evaluated 1, 7, 24, and 72 h after the first dose. In order to compare MA's effects with stress, animals were subjected to a forced swim test in a temporal pattern similar to MA administration [i.e., (30 min/session) 4 times at 2 h intervals]. Results MA increased corticosterone from 1–72 h with a peak 1 h after the first treatment, whereas glucose was only increased 1 h post-treatment. Neostriatal and hippocampal monoamines were decreased at 7, 24, and 72 h, with a concurrent increase in GFAP at 72 h. There was no effect of MA on regional brain creatine, however plasma creatinine was increased during the first 24 h and decreased by 72 h. As with MA treatment, forced swim increased corticosterone more than MA initially. Unlike MA, forced swim reduced creatine in the cerebellum with no change in other brain regions while plasma creatinine was decreased at 1 and 7 h. Glucose in plasma was decreased at 7 h. Conclusion Both MA and forced swim increase demand on energy substrates but in different ways, and MA has persistent effects on corticosterone that are not attributable to stress alone. PMID:18513404

Herring, Nicole R; Schaefer, Tori L; Tang, Peter H; Skelton, Matthew R; Lucot, James P; Gudelsky, Gary A; Vorhees, Charles V; Williams, Michael T

2008-01-01

411

Dipyrone and diclofenac do not influence creatinine-clearance, inulin-clearance or PAH-clearance in healthy male volunteers.  

PubMed

The effects of the non-steroidal anti-inflammatory drug diclofenac and the pyrazolone derivative dipyrone on renal function were compared with those of placebo in 12 healthy male volunteers in a randomized, controlled, triple-crossover study with a wash-out period of 4 days between each of the 3 trial periods (dipyrone, diclofenac and placebo) which lasted three days each. The volunteers received dipyrone (1 g, 3 times/day for 2 days, followed by twice 1 g on the main trial day, which was day 3 of each study period) or diclofenac (50 mg, 3 times/day for 2 days, followed by twice 50 mg on the main trial day) or placebo orally. Standardized meals (50 mEq sodium per day) were given from one week before the start until the end of the study and on the main trial days a protein-rich lunch (2 g protein/kg body weight) was taken. Renal function was assessed in each study period by measurement of creatinine-clearance, inulin-clearance and p-aminohippurate (PAH)-clearance to characterize glomerular filtration rate and renal plasma flow. High protein intake induced glomerular hyperfiltration (increased creatinine-clearance, inulin-clearance and PAH-clearance) in all 3 study periods (dipyrone, diclofenac, placebo). Dipyrone and diclofenac had no effect on renal clearance of creatinine, inulin or PAH in comparison to placebo. These results show that dipyrone and diclofenac at therapeutic dosages over 3 days do not decrease glomerular filtration and renal plasma flow in healthy individuals. Furthermore, it is unlikely that prostaglandins play a major role in protein-induced glomerular hyperfiltration. PMID:7599909

Farker, K; Nassr, N; Huck, F; Zerle, G; Rosenkranz, B; Schmieder, G; Hoffmann, A

1995-03-01

412

Synthesis and stacked conformations of symmetrical and unsymmetrical oligo-ureas of metaphenylenediamine.  

PubMed

The addition of substituted anilines to nitro-substituted isocyanates followed by reduction generates new aniline-substituted ureas, which can be further extended in a one- or two-directional iterative manner to form oligomeric ureas based on a m-phenylenediamine monomer. Oligo-ureas with up to eight urea linkages are reported. Fully N-substituted oligo-ureas are crystalline, and the X-ray crystal structures display ring-stacked conformations. 1H NMR studies indicate that the stacked conformation persists in solution. PMID:17343415

Clayden, Jonathan; Lemiègre, Loïc; Helliwell, Madeleine

2007-03-30

413

Accuracy of GFR estimating equations combining standardized cystatin C and creatinine assays: a cross-sectional study in Sweden.  

PubMed

Abstract Background: The recently established international cystatin C calibrator makes it possible to develop non-laboratory specific glomerular filtration rate (GFR) estimating (eGFR) equations. This study compares the performance of the arithmetic mean of the revised Lund-Malmö creatinine and CAPA cystatin C equations (MEANLM-REV+CAPA), the arithmetic mean of the Chronic Kidney Disease Epidemiology Collaboration equation (CKD-EPI) creatinine and cystatin C equations (MEANCKD-EPI), and the composite CKD-EPI equation (CKD-EPICREA+CYSC) with the corresponding single marker equations using internationally standardized calibrators for both cystatin C and creatinine. Methods: The study included 1200 examinations in 1112 adult Swedish patients referred for measurement of GFR (mGFR) 2008-2010 by plasma clearance of iohexol (median 51 mL/min/1.73 m2). Bias, precision (interquartile range, IQR) and accuracy (percentage of estimates ±30% of mGFR; P30) were compared. Results: Combined marker equations were unbiased and had higher precision and accuracy than single marker equations. Overall results of MEANLM-REV+CAPA/MEANCKD-EPI/CKD-EPICREA+CYSC were: median bias -2.2%/-0.5%/-1.6%, IQR 9.2/9.2/8.8 mL/min/1.73 m2, and P30 91.3%/91.0%/91.1%. The P30 figures were about 7-14 percentage points higher than the single marker equations. The combined equations also had a more stable performance across mGFR, age and BMI intervals, generally with P30 ?90% and never <80%. Combined equations reached P30 of 95% when the difference between eGFRCREA and eGFRCYSC was <10% but decreased to 82% at a difference of ?40%. Conclusions: Combining cystatin C and creatinine assays improves GFR estimations with P30 ?90% in adults. Reporting estimates of both single and combined marker equations in clinical settings makes it possible to assess the validity of the combined equation based on the agreement between the single marker equations. PMID:25274955

Björk, Jonas; Grubb, Anders; Larsson, Anders; Hansson, Lars-Olof; Flodin, Mats; Sterner, Gunnar; Lindström, Veronica; Nyman, Ulf

2014-10-01

414

Quantifying why urea is a protein denaturant, whereas glycine betaine is a protein stabilizer  

PubMed Central

To explain the large, opposite effects of urea and glycine betaine (GB) on stability of folded proteins and protein complexes, we quantify and interpret preferential interactions of urea with 45 model compounds displaying protein functional groups and compare with a previous analysis of GB. This information is needed to use urea as a probe of coupled folding in protein processes and to tune molecular dynamics force fields. Preferential interactions between urea and model compounds relative to their interactions with water are determined by osmometry or solubility and dissected using a unique coarse-grained analysis to obtain interaction potentials quantifying the interaction of urea with each significant type of protein surface (aliphatic, aromatic hydrocarbon (C); polar and charged N and O). Microscopic local-bulk partition coefficients Kp for the accumulation or exclusion of urea in the water of hydration of these surfaces relative to bulk water are obtained. Kp values reveal that urea accumulates moderately at amide O and weakly at aliphatic C, whereas GB is excluded from both. These results provide both thermodynamic and molecular explanations for the opposite effects of urea and glycine betaine on protein stability, as well as deductions about strengths of amide NH—amide O and amide NH—amide N hydrogen bonds relative to hydrogen bonds to water. Interestingly, urea, like GB, is moderately accumulated at aromatic C surface. Urea m-values for protein folding and other protein processes are quantitatively interpreted and predicted using these urea interaction potentials or Kp values. PMID:21930943

Guinn, Emily J.; Pegram, Laurel M.; Capp, Michael W.; Pollock, Michelle N.; Record, M. Thomas

2011-01-01

415

Urea uptake enhances barrier function and antimicrobial defense in humans by regulating epidermal gene expression  

PubMed Central

Urea is an endogenous metabolite, known to enhance stratum corneum hydration. Yet, topical urea anecdotally also improves permeability barrier function, and it appears to exhibit antimicrobial activity. Hence, we hypothesized that urea is not merely a passive metabolite, but a small-molecule regulator of epidermal structure and function. In 21 human volunteers, topical urea improved barrier function in parallel with enhanced antimicrobial peptide (LL-37 and ?-defensin-2) expression. Urea both stimulates expression of, and is transported into keratinocytes by two urea transporters, UT-A1 and UT-A2, and by aquaporin 3, 7 and 9. Inhibitors of these urea transporters block the downstream biological effects of urea, which include increased mRNA and protein levels for: (i) transglutaminase-1, involucrin, loricrin and filaggrin; (ii) epidermal lipid synthetic enzymes, and (iii) cathelicidin/LL-37 and ?-defensin-2. Finally, we explored the potential clinical utility of urea, showing that topical urea applications normalized both barrier function and antimicrobial peptide expression in a murine model of atopic dermatitis (AD). Together, these results show that urea is a small-molecule regulator of epidermal permeability barrier function and antimicrobial peptide expression after transporter uptake, followed by gene regulatory activity in normal epidermis, with potential therapeutic applications in diseased skin. PMID:22418868

Grether-Beck, Susanne; Felsner, Ingo; Brenden, Heidi; Kohne, Zippora; Majora, Marc; Marini, Alessandra; Jaenicke, Thomas; Rodriguez-Martin, Marina; Trullas, Carles; Hupe, Melanie; Elias, Peter M.; Krutmann, Jean

2012-01-01

416

Choline chloride/urea as an effective plasticizer for production of cellulose films.  

PubMed

Recently, choline chloride/urea (ChCl/urea), a typical deep eutectic solvent (DES), has been found to possess various applications in organic synthesis, electrochemistry, and nanomaterial preparation. Herein we reported the first attempt to plasticize regenerated cellulose film (RCF) using ChCl/urea as an effective plasticizer. Meanwhile, RCFs plasticized with glycerol and sorbitol were also prepared for comparison. The plasticized RCFs were investigated by Fourier transform infrared (FT-IR) spectroscopy, wide-angle X-ray diffraction (XRD), atomic force microscopy (AFM), and mechanical testing. Transparent and soft RCFs could be successfully prepared in the presence of ChCl/urea, and high elongation at break (34.88%) suggested a significant plasticizing efficiency. No new crystal and phase separation occurred to ChCl/urea plasticized RCFs. The thermal stability of ChCl/urea plasticized RCF was lowered. These results indicated that ChCl/urea was an effective plasticizer for producing cellulose films. PMID:25498618

Wang, Sha; Peng, Xinwen; Zhong, Linxin; Jing, Shuangshuang; Cao, Xuefei; Lu, Fachuang; Sun, Runcang

2015-03-01

417

Serum uric acid levels correlate with left atrial function and systolic right ventricular function in patients with newly diagnosed heart failure: the hellenic heart failure study.  

PubMed

The authors sought to investigate whether serum uric acid levels are associated with systolic left and right ventricular function, as well as left atrial function in patients with newly diagnosed heart failure. The authors enrolled 106 consecutive patients (mean age 65+/-13 years). Echocardiographic and biochemical assessment was performed during the third day of hospitalization. Pulsed tissue Doppler imaging of the systolic function of mitral and tricuspid annulus was characterized by the systolic waves (Smv and Stv, respectively), expressed in cm/s, and the left atrial function by the Amv wave. Left atrial kinetics was calculated using an equation. Serum uric acid levels were inversely correlated with Stv (P=.005) and left atrial kinetics (P=.05), after controlling for potential confounders. Uric acid levels appear to be correlated with more impaired right ventricular systolic function and decreased left atrial work in patients with heart failure. PMID:18983284

Chrysohoou, Christina; Pitsavos, Christos; Barbetseas, John; Brili, Stella; Kotroyiannis, Iason; Papademetriou, Labros; Metallinos, George; Skoumas, John; Tentolouris, Costas; Stefanadis, Christodoulos

2008-01-01

418

Highly specific and sensitive non-enzymatic determination of uric acid in serum and urine by extended gate field effect transistor sensors.  

PubMed

A potentiometric non-enzymatic sensor using off-chip extended-gate field effect transistor (EGFET) with a ferrocenyl-alkanethiol modified gold electrode is demonstrated for determining the uric acid concentration in human serum and urine. Hexacyanoferrate (II) and (III) ions are used as redox reagent. This potentiometric sensor measures the interface potential on the ferrocene immobilized gold electrode, which is modulated by the redox reaction between uric acid and hexacyanoferrate ions. The device shows a near Nernstian response to uric acid and is highly specific. The interference that comes from glucose, bilirubin, ascorbic acid and hemoglobin is negligible in normal concentration range of these interferents. The sensor also exhibits excellent long term reliability. This extended gate field effect transistor based sensors can be used as a point of care UA testing tool, due to the small size, low cost, and low sample volume consumption. PMID:23968728

Guan, Weihua; Duan, Xuexin; Reed, Mark A

2014-01-15

419

Computer experiment on aqueous solution. IV. Molecular dynamics calculation on the hydration of urea in an infinitely dilute aqueous solution with a new urea-water pair potential  

NASA Astrophysics Data System (ADS)

A molecular dynamics calculation on aqueous solution of urea has been carried out using constant temperature technique. The total number of molecules was 216, one of which was urea and the temperature was set to 298.15 K and an experimental value was used for the density. For water-water interaction, the MCY (Matsuoka-Clementi-Yoshimine) potential was used, whereas a new potential function was determined for urea-water interaction from SCF LCAO calculations for more than 800 different dimeric configurations with an STO-3G basis set and subsequent multiparameter fitting of the MO results thus obtained to an appropriate functional form by a nonlinear optimization method. The molecular dynamics calculation has been carried out up to 64 000 time steps and from the final 40 000 time steps, thermodynamic quantities, structural and energetic distribution functions, and time-dependent properties were obtained. The original water structure in the vicinity of urea molecule is slightly changed energetically by incorporation of the urea molecule. However, this energy difference is insignificant for the whole system. Instead of the possibility to form strong hydrogen bonding as estimated from the potential function, it is found that urea molecule could enter into the water structure without any appreciable distortion. This fact was confirmed by the angular dependence of any distribution function around the urea molecule. The hydrophilic region does not show a large energetic stabilization between water molecules and the system is stabilized slightly by including urea-water interaction. In contrast to this, the energy for water molecules in the hydrophobic region (above and below the plane containing urea molecule) becomes lower than that of pure water, although this region is small and water molecules cannot form a strong hydrogen bond with urea. This fact reveals that the role of each functional region, which may be either hydrophobic or hydrophilic, is similar to that of alcohol in aqueous solution, although the whole hydration structure of urea molecule is somewhat different from that of alcohol. Reflecting strong interaction of urea-water, the diffusion coefficient for shell water molecules in the vicinity of urea (within 5 Å from urea molecule) becomes smaller by 10%. Moreover, the hydration structure around urea continues for a long time (16 ps), though the energetic relaxation time is very short.

Tanaka, H.; Touhara, Hidekazu; Nakanishi, Koichiro; Watanabe, Nobuatsu

1984-05-01

420

Molecular-dynamics simulations of urea nucleation from aqueous solution.  

PubMed

Despite its ubiquitous character and relevance in many branches of science and engineering, nucleation from solution remains elusive. In this framework, molecular simulations represent a powerful tool to provide insight into nucleation at the molecular scale. In this work, we combine theory and molecular simulations to describe urea nucleation from aqueous solution. Taking advantage of well-tempered metadynamics, we compute the free-energy change associated to the phase transition. We find that such a free-energy profile is characterized by significant finite-size effects that can, however, be accounted for. The description of the nucleation process emerging from our analysis differs from classical nucleation theory. Nucleation of crystal-like clusters is in fact preceded by large concentration fluctuations, indicating a predominant two-step process, whereby embryonic crystal nuclei emerge from dense, disordered urea clusters. Furthermore, in the early stages of nucleation, two different polymorphs are seen to compete. PMID:25492932

Salvalaglio, Matteo; Perego, Claudio; Giberti, Federico; Mazzotti, Marco; Parrinello, Michele

2015-01-01

421

The xanthine oxidase inhibitor Febuxostat reduces tissue uric acid content and inhibits injury-induced inflammation in the liver and lung.  

PubMed

Necrotic cell death in vivo induces a robust neutrophilic inflammatory response and the resulting inflammation can cause further tissue damage and disease. Dying cells induce this inflammation by releasing pro-inflammatory intracellular components, one of which is uric acid. Cells contain high levels of intracellular uric acid, which is produced when purines are oxidized by the enzyme xanthine oxidase. Here we test whether a non-nucleoside xanthine oxidase inhibitor, Febuxostat (FBX), can reduce intracellular uric acid levels and inhibit cell death-induced inflammation in two different murine tissue injury models; acid-induced acute lung injury and acetaminophen liver injury. Infiltration of inflammatory cells induced by acid injection into lungs or peritoneal administration of acetaminophen was evaluated by quantification with flow cytometry and tissue myeloperoxidase activity in the presence or absence of FBX treatment. Uric acid levels in serum and tissue were measured before giving the stimuli and during inflammation. The impact of FBX treatment on the peritoneal inflammation caused by the microbial stimulus, zymosan, was also analyzed to see whether FBX had a broad anti-inflammatory effect. We found that FBX reduced uric acid levels in acid-injured lung tissue and inhibited acute pulmonary inflammation triggered by lung injury. Similarly, FBX reduced uric acid levels in the liver and inhibited inflammation in response to acetaminophen-induced hepatic injury. In contrast, FBX did not reduce inflammation to zymosan, and therefore is not acting as a general anti-inflammatory agent. These results point to the potential of using agents like FBX to treat cell death-induced inflammation. PMID:25449036

Kataoka, Hiroshi; Yang, Ke; Rock, Kenneth L

2015-01-01

422

The effect of coffee, tea, and caffeine consumption on serum uric acid and the risk of hyperuricemia in Korean Multi-Rural Communities Cohort.  

PubMed

Caffeine, a commonly consumed food constituent, is known to exert beneficial physiological effects in humans. There is a lack of comprehensive population data for the effects of caffeine intake on urate metabolism. Therefore, the aim of this study was to determine whether coffee, tea, and caffeine intake influences serum uric acid and the risk of hyperuricemia in the Korean Multi-Rural Communities Cohort. We enrolled 9,400 participants in this study. An assessment of various dietary intake amounts of substances such as coffee and tea was performed using a food frequency questionnaire. The content of caffeine was calculated from coffee (74 mg/cup) and tea (15 mg/cup) intake information from the past year. Multivariate logistic regression models, multiple linear regression models, and analysis of covariance were applied to identify any association of dietary intake with serum uric acid levels or the risk of hyperuricemia. No trends for coffee, tea, or caffeine intake were found according to each quintile with serum uric acid in males, although there were weak, marginally significant trends between the content of coffee and caffeine intake and serum uric acid level in females (p = 0.07 for both). Tea intake in males and caffeine intake in females were significantly different between non-hyperuricemia and hyperuricemia (p = 0.04 and p = 0.04, respectively). In addition, a significant association of serum uric acid level with tea intake in males (? = 0.0006, p = 0.02) and with tea intake and caffeine intake in females (? = 0.0003, p = 0.04 and ? = 0.0006, p = 0.02, respectively) was observed. There was no effect of coffee, tea, or caffeine intake on the risk of hyperuricemia in either males or females. This study suggests that caffeine consumption might have an effect on serum uric acid in females. However, coffee, tea, and caffeine intake amounts were not associated with the risk of hyperuricemia. PMID:24929540

Bae, Jisuk; Park, Pil Sook; Chun, Byung-Yeol; Choi, Bo Youl; Kim, Mi Kyung; Shin, Min-Ho; Lee, Young-Hoon; Shin, Dong Hoon; Kim, Seong-Kyu

2015-02-01

423

Urinary hydroxyproline to creatinine ratio as a biological effect marker for exposure to NO 2 and tobacco smoke  

NASA Astrophysics Data System (ADS)

In order to study the relationship between NO 2 exposure and effects, we monitored personal NO 2 exposures and the hydroxyproline to creatinine ratio in urine of about 800 women in two communities near Tokyo. Monitoring was conducted during two seasons, winter and summer 1982. The hydroxyproline to creatinine ratio (HOP:C) was determined from urine samples collected in the early morning. Daily average personal NO 2 exposures (ENO 2) were measured by using a filter badge. In both seasons, HOP:C was found to have significant correlation with ENO 2 and active and passive smoking. In addition, subjects living near major roads had significantly higher HOP:C levels in the summer compared with those living far from them. We hypothesize that these higher HOP:C levels in the summer were due to higher air exchange rates resulting in infiltration of automobile exhaust into homes. ENO 2, however, did not correlate with either the distance of the subject's house from major roads or with the amount of smoking. Stepwise multiple regression analysis revealed that HOP:C could be predicted by personal NO 2 exposures and smoking variables with a high level of confidence.

Yanagisawa, Yukio; Nishimura, Hajime; Matsuki, Hideaki; Osaka, Fumio; Kasuga, Hitoshi

424

Potent Urea and Carbamate Inhibitors of Soluble Epoxide Hydrolases  

Microsoft Academic Search

The soluble epoxide hydrolase (sEH) plays a significant role in the biosynthesis of inflammation mediators as well as xenobiotic transformations. Herein, we report the discovery of substituted ureas and carbamates as potent inhibitors of sEH. Some of these selective, competitive tightbinding inhibitors with nanomolar Ki values interacted stoichiometrically with the homogenous recombinant murine and human sEHs. These inhibitors enhance cytotoxicity

Christophe Morisseau; Marvin H. Goodrow; Deanna Dowdy; Jiang Zheng; Jessica F. Greene; James R. Sanborn; Bruce D. Hammock

1999-01-01

425

Dicyanidobis(thio­urea-?S)cadmium(II) monohydrate  

PubMed Central

In the title compound, [Cd(CN)2(CH4N2S)2]·H2O, the Cd atom lies on a twofold rotation axis and is bonded to two S atoms of thio­urea and two C atoms of the cyanide anions in a distorted tetra­hedral environment. The crystal structure is stabilized by N—H?N(CN), N—H?O, O—H?N and N—H?S hydrogen bonds. PMID:21588216

Fettouhi, Mohammed; Riaz Malik, Muhammad; Ali, Saqib; A. Isab, Anvarhusein; Ahmad, Saeed

2010-01-01

426

Growth of urea crystals by physical vapor transport  

NASA Technical Reports Server (NTRS)

This work demonstrates that high optical quality crystals of urea can be grown by the physical vapor transport method. The unique features of this method are compared with growth from methanol/water solutions. High growth rates, exceeding 2.5 mm/day, were achieved, and cm-size optical quality single crystals were obtained. Details of the growth technique and the physical properties of the crystals are presented.

Feigelson, R. S.; Route, R. K.; Kao, T.-M.

1985-01-01

427

Reverse osmosis membrane of high urea rejection properties. [water purification  

NASA Technical Reports Server (NTRS)

Polymeric membranes suitable for use in reverse osmosis water purification because of their high urea and salt rejection properties are prepared by generating a plasma of an unsaturated hydrocarbon monomer and nitrogen gas from an electrical source. A polymeric membrane is formed by depositing a polymer of the unsaturated monomer from the plasma onto a substrate, so that nitrogen from the nitrogen gas is incorporated within the polymer in a chemically combined form.

Johnson, C. C.; Wydeven, T. J. (inventors)

1980-01-01

428

A novel disposable electrochemical immunosensor for phenyl urea herbicide diuron  

Microsoft Academic Search

A disposable electrochemical immunosensor has been developed for the determination of phenyl urea herbicide-diuron using a low cost laser ablated gold electrodes (LC-LAGE) fabricated on polystyrene substrate. The electrodes were electrochemically deposited with prussian blue-gold nanoparticle (PB-GNP) film, and a competitive inhibition immunoassay was performed on LC-LAGE by using a specific hapten–protein conjugate. The binding of available diuron specific antibody

Priyanka Sharma; Kavita Sablok; Vijayender Bhalla; C. Raman Suri

2011-01-01

429

A Potential Role for Plasma Uric Acid in the Endothelial Pathology of Plasmodium falciparum malaria  

PubMed Central

Background Inflammatory cytokinemia and systemic activation of the microvascular endothelium are central to the pathogenesis of Plasmodium falciparum malaria. Recently, ‘parasite-derived’ uric acid (UA) was shown to activate human immune cells in vitro, and plasma UA levels were associated with inflammatory cytokine levels and disease severity in Malian children with malaria. Since UA is associated with endothelial inflammation in non-malaria diseases, we hypothesized that elevated UA levels contribute to the endothelial pathology of P. falciparum malaria. Methodology/Principal Findings We measured levels of UA and soluble forms of intercellular adhesion molecule-1 (sICAM-1), vascular cell adhesion molecule-1 (sVCAM-1), E-selectin (sE-Selectin), thrombomodulin (sTM), tissue factor (sTF) and vascular endothelial growth factor (VEGF) in the plasma of Malian children aged 0.5–17 years with uncomplicated malaria (UM, n?=?487) and non-cerebral severe malaria (NCSM, n?=?68). In 69 of these children, we measured these same factors once when they experienced a malaria episode and twice when they were healthy (i.e., before and after the malaria transmission season). We found that levels of UA, sICAM-1, sVCAM-1, sE-Selectin and sTM increase during a malaria episode and return to basal levels at the end of the transmission season (p<0.0001). Plasma levels of UA and these four endothelial biomarkers correlate with parasite density and disease severity. In children with UM, UA levels correlate with parasite density (r?=?0.092, p?=?0.043), sICAM-1 (r ?=?0.255, p<0.0001) and sTM (r?=?0.175, p?=?0.0001) levels. After adjusting for parasite density, UA levels predict sTM levels. Conclusions/Significance Elevated UA levels may contribute to malaria pathogenesis by damaging endothelium and promoting a procoagulant state. The correlation between UA levels and parasite densities suggests that parasitized erythrocytes are one possible source of excess UA. UA-induced shedding of endothelial TM may represent a novel mechanism of malaria pathogenesis, in which activated thrombin induces fibrin deposition and platelet aggregation in microvessels. This protocol is registered at clinicaltrials.gov (NCT00669084). PMID:23349902

Mita-Mendoza, Neida K.; van de Hoef, Diana L.; Lopera-Mesa, Tatiana M.; Doumbia, Saibou; Konate, Drissa; Doumbouya, Mory; Gu, Wenjuan; Anderson, Jennifer M.; Santos-Argumedo, Leopoldo; Rodriguez, Ana; Fay, Michael P.; Diakite, Mahamadou; Long, Carole A.; Fairhurst, Rick M.

2013-01-01

430

Association of Uric Acid with Metabolic Syndrome in Men, Premenopausal Women and Postmenopausal Women  

PubMed Central

Objective: To explore the relationship between serum uric acid (SUA) and metabolic syndrome (MS) in men, premenopausal women and postmenopausal women. Methods: A cross-sectional study was conducted in 1,834 community-based Southern Chinese participants from June to October 2012. Sex-specific SUA quartiles were used as follows: <345, 345–<400, 400–<468, ?468 µmol/L in males; and <248, 248–<288, 288–<328, ?328 µmol/L in females. MS was defined by the National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) Criteria. The association between SUA and MS was then analyzed using the STATA software. Results: The odds ratio (OR) for having MS in the highest versus lowest quartiles of SUA levels was 2.46 (95% confidence interval [CI], 1.39 to 4.34, p = 0.002) in men after adjusting for age, sex, history of coronary heart disease, history of stroke, current current smoking, current alcohol use, physical inactivity, education status, and BMI. Further adjusting for above confounders, hypertension and diabetes, the OR for having MS in the highest versus lowest quartiles of SUA was 3.06 (95% CI, 1.64 to 5.70, p < 0.001). The OR for having MS in the highest versus lowest quartiles of SUA was 3.45 (95% CI, 1.38 to 8.64, p = 0.008) and 1.98 (95% CI, 1.16 to 3.37, p = 0.08) in premenopausal women and postmenopausal women after adjusting for age, sex, history of coronary heart disease, history of stroke, current smoking, current alcohol use, physical inactivity, education status, and BMI. Further adjusting for above confounders, hypertension and diabetes, the OR for having MS in the highest versus lowest quartiles of SUA was 3.42 (95% CI, 1.15 to 10.18, p = 0.03) and 1.87 (95% CI, 1.05 to 3.33, p = 0.03) in premenopausal women and postmenopausal women. Conclusions: Higher SUA levels are positively associated with the presence of MS in males and females. Higher SUA levels had a higher risk of having MS in premenopausal women than in postmenopausal women. PMID:24619122

Li, Yongqiang; Chen, Shanying; Shao, Xiaofei; Guo, Jia; Liu, Xinyu; Liu, Aiqun; Zhang, Ying; Wang, Honglei; Li, Bin; Deng, Kangping; Liu, Qin; Holthöfer, Harry; Zou, Hequn

2014-01-01